COL3A1 Signaling Pathway

7440-43-9

BDOSMKKIYDKNTQ-UHFFFAOYSA-N

Cadmium

Cadimium CADMIUM BLUE CADMIUM, IN PLATTEN, STANGEN, BROCKEN,KOERNER

DTXSID1023940

67-66-3

HEDRZPFGACZZDS-UHFFFAOYSA-N

Chloroform

Trichloromethane Methane, trichloro- CARBON TRICHLORIDE Chloroforme cloroformo Formyl trichloride Methane trichloride Methane,trichloro- NSC 77361 Trichloroform UN 1888

DTXSID1020306

110-00-9

YLQBMQCUIZJEEH-UHFFFAOYSA-N

Furan

Divinylene oxide furanne Furfuran Oxacyclopentadiene Tetrole UN 2389

DTXSID6020646

FMA:84050

FMA Cytokine

CHEBI:26523

CHEBI reactive oxygen species

GO:0031012

GO extracellular matrix

CL:0000066

CL epithelial cell

CL:0000077

CL mesothelial cell

UBERON:0002107

UBERON liver

HP:0012852

HP Hepatic bridging fibrosis

GO:0050663

GO cytokine secretion

GO:1903409

GO reactive oxygen species biosynthetic process

GO:0070265

GO necrotic cell death

GO:0006915

GO apoptotic process

GO:0008283

GO cell proliferation

MP:0003333

MP liver fibrosis

WIKI increased

WIKI morphological change

WIKI occurrence

Cadmium

2017-10-25T08:33:12

Ionizing Radiation Ionizing radiation can vary in energy, dose, charge, and in the spatial distributions of energy transferred to other matter (linear energy transfer per unit length or LET) (ICRU 1970). At the same dose, low and high LET both generate energy deposition events, including many higher energy events (Goodhead and Nikjoo 1989). However, they differ in the spatial distribution and upper range of intensity of energy deposited. Lower LET such as gamma rays sparsely deposit many individual excitations or small clusters of excitations of low energy (Goodhead 1988). In contrast, high LET such as alpha particles have fewer tracks but readily transfer their energy to matter and therefore deposit their energy over a much smaller area (Goodhead 1994). Consequently, alpha and other high LET particles penetrate less deeply into tissue, interactions are densely focused on a narrow track, and individual energy depositions can be large (Goodhead 1988). These different energy deposition patterns can lead to differences in radiation effects including the pattern of DNA damage.

Exposure to ionizing radiation can come from natural and industrial sources. Space and terrestrial radiation includes a range of LET particles, while diagnostic radiation methods such as X-ray imaging, mammography and CT scans use low LET X-rays. Radiation therapy can use an external beam to direct radiation on a focused tissue area, or deposit solid or liquid radioactive materials in the body that release (mostly gamma) radiation internally. External radiotherapy typically uses X-rays but is moving towards higher LET charged particles such as protons and heavy ions (Durante, Orecchia et al. 2017).

2019-05-03T12:36:36

2019-05-07T12:12:13

Chloroform

2016-11-29T18:42:27

furan

2020-05-01T14:35:22

too many stressors to list

2020-05-01T14:58:07

9606

NCBI Homo sapiens

10090

NCBI mouse

WCS_9606

common toxicological species human

WikiUser_28

Vertebrates

WikiUser_25

Wikiuser: Cyauk human and other cells in culture

WCS_35525

common ecological species crustaceans

WCS_4472

common ecological species Lemna minor

WCS_7955

common ecological species zebrafish

10090

NCBI Mus musculus

10116

NCBI Rattus norvegicus

6239

NCBI Caenorhabditis elegans

10116

NCBI rat

WikiUser_26

ApacheUser rodents

WikiUser_17

mammals

COL3A1 Signaling Pathway

Molecular

This key event is characterised by the abnormal transcriptional activation and protein upregulation of Collagen Type III Alpha 1 (COL3A1). As a core structural component of the extracellular matrix (ECM) in various organs, including the liver, the enrichment and activation of the COL3A1 signalling cascade serve as a critical molecular initiating signalling event that drives tissue remodelling and structural stiffening [1-3].

Gene Expression Analysis (Transcriptional Level): RT-qPCR (Reverse Transcription-Quantitative Polymerase Chain Reaction): Widely used to quantify the relative mRNA expression levels of the Col3a1 gene in tissue samples or cultured cells. Transcriptomics (RNA-Seq / Microarray): High-throughput sequencing can detect the global enrichment of the COL3A1 pathway and related extracellular matrix (ECM)-receptor interaction gene sets via Gene Set Enrichment Analysis (GSEA) or KEGG pathway analysis.

The structural organization of Collagen Type III are known to be highly conserved throughout mammalian evolution[4].

Not Specified Unspecific

Not Specified

Not Otherwise Specified

High High

1. Xu, Y., Mu, W., Li, J., Ba, Q., & Wang, H. (2021). Chronic cadmium exposure at environmental-relevant level accelerates the development of hepatotoxicity to hepatocarcinogenesis. Science of The Total Environment, 783. doi:10.1016/j.scitotenv.2021.146958 2. Li Y, Jian Y, Zhou J, Zhang M, Zhou Y, Ge Y, Wang H, Mu W. Molecular regulatory networks of microplastics and cadmium mediated hepatotoxicity from NAFLD to tumorigenesis via integrated approaches. Ecotoxicol Environ Saf. 2025 Jul 15;300:118431. doi: 10.1016/j.ecoenv.2025.118431. 3. Chen J, Ge J, Chen W, Zhao Y, Song T, Fu K, Li X, Zheng Y. UPLC-Q-TOF-MS based investigation into the bioactive compounds and molecular mechanisms of Lamiophlomis Herba against hepatic fibrosis. Phytomedicine. 2023 Dec;121:155085. doi: 10.1016/j.phymed.2023.155085. Epub 2023 Sep 16. PMID: 37757709. 4.Gelse K, Pöschl E, Aigner T. Collagens--structure, function, and biosynthesis. Adv Drug Deliv Rev. 2003 Nov 28;55(12):1531-46. doi: 10.1016/j.addr.2003.08.002. PMID: 14623400. AOPWiki 2026-03-25T08:17:22

2026-06-04T02:17:02

Release, Cytokine

Cellular

Cytokines are small, soluble molecules secreted by cells to enable intercellular communication. Cytokines may act on the cells that secrete them (autocrine action), on nearby cells (paracrine action), as well as on distant cells (endocrine action). Cytokines can act synergistically or antagonistically, and secretion from one cell can trigger upregulation of a further range of cytokines from the same cell or others <a href="#cite_note-1">[1]</a>. Most cells in the body are able to secrete them, and several subfamilies belong to the group of cytokines, such as chemokines, interferons, interleukins, tumor necrosis factors (TNF), transforming growth factors (TGF) and colony-stimulating factors. They are important players in modulating fundamental biological processes, including body growth, adiposity, lactation, hematopoiesis, and also inflammation and immunity<a href="#cite_note-Braunersreuther2012-2">[2]</a>. Damaged cells, such as apoptotic cells, can trigger the upregulation and release of cytokines to induce the inflammatory response. An important receptor responsible for cell death-related cytokine regulation is Fas, a cell surface glycoprotein which belongs to the tumor necrosis factor (TNF) receptor family. The role of Fas in the onset of inflammation by upregulating inflammatory cytokines is increasingly discussed. Fas-activation can trigger the production of MCP-1 and IL-8 and its associated chemotaxis of phagocytes toward apoptotic cells<a href="#cite_note-Cullen2013-3">[3]</a>. TNF-α is an inflammatory mediator that can be secreted by many cell types, including hepatocytes and Kupffer cells. TNF-induced cytokines and chemokines, such as IL-6, IL-8, GMCSF, CXCL1, and RANTES, can trigger immune responses by producing acute phase proteins and recruitment of inflammatory cells such as neutrophils, macrophages, and basophils to the site of inflammation. Moreover, an increased production of monocytes/macrophages from bone marrow is triggered<a href="#cite_note-Cullen2013-3">[3]</a>. On the other hand, inflammation can be suppressed by cytokines and mediators such as IL-10 and TGF-β. In the liver, TGF-β1 is the most abundant isoform and is secreted by immune cells, stellate cells, and epithelial cells. IL-10 inhibits T cell-, monocyte-, and macrophage-mediated functions and has been detected in several liver cells, in¬cluding hepatocytes, stellate cells, and Kupffer cells <a href="#cite_note-Braunersreuther2012-2">[2]</a>.

Methods that have been previously reviewed and approved by a recognized authority should be included in the Overview section above. All other methods, including those well established in the published literature, should be described here. Consider the following criteria when describing each method: 1. Is the assay fit for purpose? 2. Is the assay directly or indirectly (i.e. a surrogate) related to a key event relevant to the final adverse effect in question? 3. Is the assay repeatable? 4. Is the assay reproducible? mRNA expression levels of inflammatory cytokines can be determined by using real-time PCR as described in <a href="#cite_note-Cui2011-4">[4]</a>. Equally, In Situ Hybridization of mRNA in liver tissue can be used <a href="#cite_note-Faouzi2001-5">[5]</a>. Plasma levels of pro-inflammatory cytokines, or levels in cell supernatants can be analysed by enzyme linked immunosorbent assay (ELISA) using commercial kits <a href="#cite_note-Ma2009-6">[6]</a><a href="#cite_note-Cullen2013-3">[3]</a>. A more advanced system was described recently by using a multiplex immunoassay platform. In a 96 well plate format the authors describe the analysis of blood, urine and breath samples of human volunteers in a Meso Scale Discovery (MSD) multiplex electrochemiluminescent immunoassay system <a href="#cite_note-Stiegel2015-7">[7]</a>.

<a href="#cite_note-Cui2011-4">[4]</a><a href="#cite_note-Ma2009-6">[6]</a><a href="#cite_note-Faouzi2001-5">[5]</a>: mouse <a href="#cite_note-Cullen2013-3">[3]</a><a href="#cite_note-Stiegel2015-7">[7]</a>: human

CL:0000255

CL eukaryotic cell

High High

<ol class="references"> <li id="cite_note-1"><a href="#cite_ref-1">↑</a> Zhang JM, An J. Cytokines, inflammation, and pain. Int Anesthesiol Clin. 2007 Spring;45(2):27-37 </li> <li id="cite_note-Braunersreuther2012-2">↑ <a href="#cite_ref-Braunersreuther2012_2-0">2.0</a> <a href="#cite_ref-Braunersreuther2012_2-1">2.1</a> Braunersreuther V, Viviani GL, Mach F, Montecucco F. Role of cytokines and chemokines in non-alcoholic fatty liver disease. World J Gastroenterol. 2012 Feb 28;18(8):727-35 </li> <li id="cite_note-Cullen2013-3">↑ <a href="#cite_ref-Cullen2013_3-0">3.0</a> <a href="#cite_ref-Cullen2013_3-1">3.1</a> <a href="#cite_ref-Cullen2013_3-2">3.2</a> <a href="#cite_ref-Cullen2013_3-3">3.3</a> Cullen SP, Henry CM, Kearney CJ, Logue SE, Feoktistova M, Tynan GA, Lavelle EC, Leverkus M, Martin SJ. Fas/CD95-induced chemokines can serve as "find-me" signals for apoptotic cells. Mol Cell. 2013 Mar 28;49(6):1034-48 </li> <li id="cite_note-Cui2011-4">↑ <a href="#cite_ref-Cui2011_4-0">4.0</a> <a href="#cite_ref-Cui2011_4-1">4.1</a> Cui Y, Liu H, Zhou M, Duan Y, Li N, Gong X, Hu R, Hong M, Hong F. Signaling pathway of inflammatory responses in the mouse liver caused by TiO2 nanoparticles. 2011; J. Biomed. Mater. Res. - Part A 96 A:221–229 </li> <li id="cite_note-Faouzi2001-5">↑ <a href="#cite_ref-Faouzi2001_5-0">5.0</a> <a href="#cite_ref-Faouzi2001_5-1">5.1</a> Faouzi S, Burckhardt BE, Hanson JC, Campe CB, Schrum LW, Rippe RA, Maher JJ. Anti-Fas induces hepatic chemokines and promotes inflammation by an NF-kappa B-independent, caspase-3-dependent pathway. J Biol Chem. 2001 Dec 28;276(52):49077-82 </li> <li id="cite_note-Ma2009-6">↑ <a href="#cite_ref-Ma2009_6-0">6.0</a> <a href="#cite_ref-Ma2009_6-1">6.1</a> Ma L, Zhao J, Wang J, Liu J, Duan Y, Liu H, Li N, Yan J, Ruan J, Wang H, Hong F. The Acute Liver Injury in Mice Caused by Nano-Anatase TiO2. Nanoscale Res Lett. 2009 Aug 1;4(11):1275-85 </li> <li id="cite_note-Stiegel2015-7">↑ <a href="#cite_ref-Stiegel2015_7-0">7.0</a> <a href="#cite_ref-Stiegel2015_7-1">7.1</a> Stiegel MA, Pleil JD, Sobus JR, Morgan MK, Madden MC. Analysis of inflammatory cytokines in human blood, breath condensate, and urine using a multiplex immunoassay platform. Biomarkers. 2015 Feb;20(1):35-46 </li> </ol> AOPWiki 2016-11-29T18:41:22

2017-09-16T10:14:42

Increase, Reactive oxygen species

Increase, ROS

Cellular

Biological State: increased reactive oxygen species (ROS) Biological compartment: an entire cell -- may be cytosolic, may also enter organelles. Reactive oxygen species (ROS) are O2- derived molecules that can be both free radicals (e.g. superoxide, hydroxyl, peroxyl, alcoxyl) and non-radicals (hypochlorous acid, ozone and singlet oxygen) (Bedard and Krause 2007; Ozcan and Ogun 2015). ROS production occurs naturally in all kinds of tissues inside various cellular compartments, such as mitochondria and peroxisomes (Drew and Leeuwenburgh 2002; Ozcan and Ogun 2015). Furthermore, these molecules have an important function in the regulation of several biological processes – they might act as antimicrobial agents or triggers of animal gamete activation and capacitation (Goud et al. 2008; Parrish 2010; Bisht et al. 2017).  However, in environmental stress situations (exposure to radiation, chemicals, high temperatures) these molecules have its levels drastically increased, and overly interact with macromolecules, namely nucleic acids, proteins, carbohydrates and lipids, causing cell and tissue damage (Brieger et al. 2012; Ozcan and Ogun 2015).  <div> Reactive oxygen species (ROS) refers to the chemical species superoxide, hydrogen peroxide, and their secondary reactive products. In the biological context, ROS are signaling molecules with important roles in cell energy metabolism, cell proliferation, and fate. Therefore, balancing ROS levels at the cellular and tissue level is an important part of many biological processes. Disbalance, mainly an increase in ROS levels, can cause cell dysfunction and irreversible cell damage. ROS are produced from both exogenous stressors and normal endogenous cellular processes, such as the mitochondrial electron transport chain (ETC). Inhibition of the ETC can result in the accumulation of ROS. Exposure to chemicals, heavy metal ions, or ionizing radiation can also result in increased production of ROS. Chemicals and heavy metal ions can deplete cellular antioxidants reducing the cell’s ability to control cellular ROS and resulting in the accumulation of ROS. Cellular antioxidants include glutathione (GSH), protein sulfhydryl groups, superoxide dismutase (SOD). ROS are radicals, ions, or molecules that have a single unpaired electron in their outermost shell of electrons, which can be categorized into two groups: free oxygen radicals and non-radical ROS [Liou et al., 2010]. <Free oxygen radicals> <div> <table cellspacing="0" class="MsoTableGrid" style="border-collapse:collapse; border:none"> <tbody> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:2px solid black; vertical-align:top; width:290px"> superoxide </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:2px solid black; vertical-align:top; width:290px"> O2·- </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> hydroxyl radical </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> ·OH </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> nitric oxide </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> NO· </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> organic radicals </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> R· </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> peroxyl radicals </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> ROO· </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> alkoxyl radicals </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> RO· </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> thiyl radicals </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> RS· </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> sulfonyl radicals </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> ROS· </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> thiyl peroxyl radicals </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> RSOO· </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> disulfides </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> RSSR </td> </tr> </tbody> </table> </div> <Non-radical ROS> <div> <table cellspacing="0" class="MsoTableGrid" style="border-collapse:collapse; border:none"> <tbody> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:2px solid black; vertical-align:top; width:290px"> hydrogen peroxide </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:2px solid black; vertical-align:top; width:290px"> H2O2 </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> singlet oxygen </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> 1O2 </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> ozone/trioxygen </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> O3 </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> organic hydroperoxides </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> ROOH </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> hypochlorite </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> ClO- </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> peroxynitrite </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> ONOO- </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> nitrosoperoxycarbonate anion </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> O=NOOCO2- </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> nitrocarbonate anion </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> O2NOCO2- </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> dinitrogen dioxide </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> N2O2 </td> </tr> <tr> <td style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> nitronium </td> <td style="border-bottom:2px solid black; border-left:none; border-right:2px solid black; border-top:none; vertical-align:top; width:290px"> NO2+ </td> </tr> <tr> <td colspan="2" style="border-bottom:2px solid black; border-left:2px solid black; border-right:2px solid black; border-top:none; vertical-align:top; width:580px"> highly reactive lipid- or carbohydrate-derived carbonyl compounds </td> </tr> </tbody> </table> </div> Potential sources of ROS include NADPH oxidase, xanthine oxidase, mitochondria, nitric oxide synthase, cytochrome P450, lipoxygenase/cyclooxygenase, and monoamine oxidase [Granger et al., 2015]. ROS are generated through NADPH oxidases consisting of p47phox and p67phox. ROS are generated through xanthine oxidase activation in sepsis [Ramos et al., 2018]. Arsenic produces ROS [Zhang et al., 2011]. Mitochondria-targeted paraquat and metformin mediate ROS production [Chowdhury et al., 2020]. ROS are generated by bleomycin [Lu et al., 2010]. Radiation induces dose-dependent ROS production [Ji et al., 2019]. ROS are generated in the course of cellular respiration, metabolism, cell signaling, and inflammation [Dickinson and Chang 2011; Egea et al. 2017]. Hydrogen peroxide is also made by the endoplasmic reticulum in the course of protein folding. Nitric oxide (NO) is produced at the highest levels by nitric oxide synthase in endothelial cells and phagocytes. NO production is one of the main mechanisms by which phagocytes kill bacteria [Wang et al., 2017]. The other species are produced by reactions with superoxide or peroxide, or by other free radicals or enzymes. ROS activity is principally local. Most ROS have short half-lives, ranging from nano- to milliseconds, so diffusion is limited, while reactive nitrogen species (RNS) nitric oxide or peroxynitrite can survive long enough to diffuse across membranes [Calcerrada et al. 2011]. Consequently, local concentrations of ROS are much higher than average cellular concentrations, and signaling is typically controlled by colocalization with redox buffers [Dickinson and Chang 2011; Egea et al. 2017]. Although their existence is limited temporally and spatially, ROS interact with other ROS or with other nearby molecules to produce more ROS and participate in a feedback loop to amplify the ROS signal, which can increase RNS. Both ROS and RNS also move into neighboring cells, and ROS can increase intracellular ROS signaling in neighboring cells [Egea et al. 2017]. In the primary event, photoreactive chemicals are excited by the absorption of photon energy.  The energy of the photoactivated chemicals transfer to oxygen and then generates the reactive oxygen species (ROS), including superoxide (O2−) via type I reaction and singlet oxygen (1O2) via type II reaction, as principal intermediate species in phototoxic reaction (Foote, 1991, Onoue et al. , 2009). </div>

Photocolorimetric assays (Sharma et al. 2017; Griendling et al. 2016) or through commercial kits purchased from specialized companies. Yuan, Yan, et al., (2013) described ROS monitoring by using H2-DCF-DA, a redox-sensitive fluorescent dye. Briefly, the harvested cells were incubated with H2-DCF-DA (50 µmol/L final concentration) for 30 min in the dark at 37°C. After treatment, cells were immediately washed twice, re-suspended in PBS, and analyzed on a BD-FACS Aria flow cytometry. ROS generation was based on fluorescent intensity which was recorded by excitation at 504 nm and emission at 529 nm. Lipid peroxidation (LPO) can be measured as an indicator of oxidative stress damage Yen, Cheng Chien, et al., (2013). Chattopadhyay, Sukumar, et al. (2002) assayed the generation of free radicals within the cells and their extracellular release in the medium by addition of yellow NBT salt solution (Park et al., 1968). Extracellular release of ROS converted NBT to a purple colored formazan. The cells were incubated with 100 ml of 1 mg/ml NBT solution for 1 h at 37 °C and the product formed was assayed at 550 nm in an Anthos 2001 plate reader. The observations of the ‘cell-free system’ were confirmed by cytological examination of parallel set of explants stained with chromogenic reactions for NO and ROS. On the basis of the pathogenesis of drug-induced phototoxicity, a reactive oxygen species (ROS) assay was proposed to evaluate the phototoxic risk of chemicals. The ROS assay can monitor generation of ROS, such as singlet oxygen and superoxide, from photoirradiated chemicals, and the ROS data can be used to evaluate the photoreactivity of chemicals (Onoue et al. , 2014, Onoue et al. , 2013, Onoue and Tsuda, 2006).  The ROS assay is a recommended approach by guidelines to evaluate the phototoxic risk of chemicals (ICH, 2014, PCPC, 2014). <div> <Direct detection> Many fluorescent compounds can be used to detect ROS, some of which are specific, and others are less specific. ・ROS can be detected by fluorescent probes such as p-methoxy-phenol derivative [Ashoka et al., 2020]. ・Chemiluminescence analysis can detect the superoxide, where some probes have a wider range for detecting hydroxyl radical, hydrogen peroxide, and peroxynitrite [Fuloria et al., 2021]. ・ROS in the blood can be detected using superparamagnetic iron oxide nanoparticles (SPION)-based biosensor [Lee et al., 2020]. ・Hydrogen peroxide (H2O2) can be detected with a colorimetric probe, which reacts with H2O2 in a 1:1 stoichiometry to produce a bright pink colored product, followed by the detection with a standard colorimetric microplate reader with a filter in the 540-570 nm range. ・The levels of ROS can be quantified using multiple-step amperometry using a stainless steel counter electrode and non-leak Ag|AgCl reference node [Flaherty et al., 2017]. ・Singlet oxygen can be measured by monitoring the bleaching of p-nitrosodimethylaniline at 440 nm using a spectrophotometer with imidazole as a selective acceptor of singlet oxygen [Onoue et al., 2014]. <Indirect Detection> Alternative methods involve the detection of redox-dependent changes to cellular constituents such as proteins, DNA, lipids, or glutathione [Dickinson and Chang 2011; Wang et al. 2013; Griendling et al. 2016]. However, these methods cannot generally distinguish between the oxidative species behind the changes and cannot provide good resolution for the kinetics of oxidative activity. </div>

ROS is a normal constituent found in all organisms, lifestages, and sexes.

UBERON:0000062

UBERON organ

CL:0000000

CL cell

High Unspecific High Mixed

High

All life stages

High Moderate Moderate Moderate High High High

Akai, K., et al. (2004). "Ability of ferric nitrilotriacetate complex with three pH-dependent conformations to induce lipid peroxidation." Free Radic Res. Sep;38(9):951-62. doi: 10.1080/1071576042000261945 Ashoka, A. H., et al. (2020). "Recent Advances in Fluorescent Probes for Detection of HOCl and HNO." ACS omega, 5(4), 1730-1742. doi:10.1021/acsomega.9b03420 B.H. Park, S.M. Fikrig, E.M. Smithwick Infection and nitroblue tetrazolium reduction by neutrophils: a diagnostic aid Lancet, 2 (1968), pp. 532-534 Bedard, Karen, and Karl-Heinz Krause. 2007. “The NOX Family of ROS-Generating NADPH Oxidases: Physiology and Pathophysiology.” Physiological Reviews 87 (1): 245–313. Bisht, Shilpa, Muneeb Faiq, Madhuri Tolahunase, and Rima Dada. 2017. “Oxidative Stress and Male Infertility.” Nature Reviews. Urology 14 (8): 470–85. Brieger, K., S. Schiavone, F. J. Miller Jr, and K-H Krause. 2012. “Reactive Oxygen Species: From Health to Disease.” Swiss Medical Weekly 142 (August): w13659. Calcerrada, P., et al. (2011). "Nitric oxide-derived oxidants with a focus on peroxynitrite: molecular targets, cellular responses and therapeutic implications." Curr Pharm Des 17(35): 3905-3932. Chattopadhyay, Sukumar, et al. "Apoptosis and necrosis in developing brain cells due to arsenic toxicity and protection with antioxidants." Toxicology letters 136.1 (2002): 65-76. Chowdhury, A. R., et al. (2020). "Mitochondria-targeted paraquat and metformin mediate ROS production to induce multiple pathways of retrograde signaling: A dose-dependent phenomenon." Redox Biol. doi: 10.1016/j.redox.2020.101606. PMID: 32604037; PMCID: PMC7327929. Dickinson, B. C. and Chang C. J. (2011). "Chemistry and biology of reactive oxygen species in signaling or stress responses." Nature chemical biology 7(8): 504-511. Drew, Barry, and Christiaan Leeuwenburgh. 2002. “Aging and the Role of Reactive Nitrogen Species.” Annals of the New York Academy of Sciences 959 (April): 66–81. Egea, J., et al. (2017). "European contribution to the study of ROS: A summary of the findings and prospects for the future from the COST action BM1203 (EU-ROS)." Redox biology 13: 94-162. Flaherty, R. L., et al. (2017). "Glucocorticoids induce production of reactive oxygen species/reactive nitrogen species and DNA damage through an iNOS mediated pathway in breast cancer." Breast Cancer Research, 19(1), 1–13. https://doi.org/10.1186/s13058-017-0823-8 Foote CS. Definition of type I and type II photosensitized oxidation. Photochem Photobiol. 1991;54:659. Fuloria, S., et al. (2021). "Comprehensive Review of Methodology to Detect Reactive Oxygen Species (ROS) in Mammalian Species and Establish Its Relationship with Antioxidants and Cancer." Antioxidants (Basel, Switzerland) 10(1) 128. doi:10.3390/antiox10010128 Go, Y. M. and Jones, D. P. (2013). "The redox proteome." J Biol Chem 288(37): 26512-26520. Goud, Anuradha P., Pravin T. Goud, Michael P. Diamond, Bernard Gonik, and Husam M. Abu-Soud. 2008. “Reactive Oxygen Species and Oocyte Aging: Role of Superoxide, Hydrogen Peroxide, and Hypochlorous Acid.” Free Radical Biology & Medicine 44 (7): 1295–1304. Granger, D. N. and Kvietys, P. R. (2015). "Reperfusion injury and reactive oxygen species: The evolution of a concept" Redox Biol. doi: 10.1016/j.redox.2015.08.020. PMID: 26484802; PMCID: PMC4625011. Griendling, K. K., et al. (2016). "Measurement of Reactive Oxygen Species, Reactive Nitrogen Species, and Redox-Dependent Signaling in the Cardiovascular System: A Scientific Statement From the American Heart Association." Circulation research 119(5): e39-75. Griendling, Kathy K., Rhian M. Touyz, Jay L. Zweier, Sergey Dikalov, William Chilian, Yeong-Renn Chen, David G. Harrison, Aruni Bhatnagar, and American Heart Association Council on Basic Cardiovascular Sciences. 2016. “Measurement of Reactive Oxygen Species, Reactive Nitrogen Species, and Redox-Dependent Signaling in the Cardiovascular System: A Scientific Statement From the American Heart Association.” Circulation Research 119 (5): e39–75. ICH. ICH Guideline S10 Guidance on Photosafety Evaluation of Pharmaceuticals.: International Council on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use; 2014. Itziou, A., et al. (2011). "In vivo and in vitro effects of metals in reactive oxygen species production, protein carbonylation, and DNA damage in land snails Eobania vermiculata." Archives of Environmental Contamination and Toxicology, 60(4), 697–707. https://doi.org/10.1007/s00244-010-9583-5 Ji, W. O., et al. "Quantitation of the ROS production in plasma and radiation treatments of biotargets." Sci Rep. 2019 Dec 27;9(1):19837. doi: 10.1038/s41598-019-56160-0. PMID: 31882663; PMCID: PMC6934759. Kruk, J. and Aboul-Enein, H. Y. (2017). "Reactive Oxygen and Nitrogen Species in Carcinogenesis: Implications of Oxidative Stress on the Progression and Development of Several Cancer Types." Mini-Reviews in Medicinal Chemistry, 17:11. doi:10.2174/1389557517666170228115324 Lee, D. Y., et al. (2020). "PEGylated Bilirubin-coated Iron Oxide Nanoparticles as a Biosensor for Magnetic Relaxation Switching-based ROS Detection in Whole Blood." Theranostics, 10(5), 1997-2007. doi:10.7150/thno.39662 Li, Z., et al. (2020). "Inhibition of MiR-25 attenuates doxorubicin-induced apoptosis, reactive oxygen species production and DNA damage by targeting pten." International Journal of Medical Sciences, 17(10), 1415–1427. https://doi.org/10.7150/ijms.41980 Liou, G. Y. and Storz, P. "Reactive oxygen species in cancer." Free Radic Res. 2010 May;44(5):479-96. doi:10.3109/10715761003667554. PMID: 20370557; PMCID: PMC3880197. Lu, Y., et al. (2010). "Phosphatidylinositol-3-kinase/akt regulates bleomycin-induced fibroblast proliferation and collagen production." American journal of respiratory cell and molecular biology, 42(4), 432–441. https://doi.org/10.1165/rcmb.2009-0002OC Onoue, S., et al. (2013). "Establishment and intra-/inter-laboratory validation of a standard protocol of reactive oxygen species assay for chemical photosafety evaluation." J Appl Toxicol. 33(11):1241-50. doi: 10.1002/jat.2776. Epub 2012 Jun 13. PMID: 22696462. Onoue S, Hosoi K, Toda T, Takagi H, Osaki N, Matsumoto Y, et al. Intra-/inter-laboratory validation study on reactive oxygen species assay for chemical photosafety evaluation using two different solar simulators. Toxicology in vitro : an international journal published in association with BIBRA. 2014;28:515-23. Onoue S, Hosoi K, Wakuri S, Iwase Y, Yamamoto T, Matsuoka N, et al. Establishment and intra-/inter-laboratory validation of a standard protocol of reactive oxygen species assay for chemical photosafety evaluation. Journal of applied toxicology : JAT. 2013;33:1241-50. Onoue S, Kawamura K, Igarashi N, Zhou Y, Fujikawa M, Yamada H, et al. Reactive oxygen species assay-based risk assessment of drug-induced phototoxicity: classification criteria and application to drug candidates. J Pharm Biomed Anal. 2008;47:967-72. Onoue S, Seto Y, Gandy G, Yamada S. Drug-induced phototoxicity; an early in vitro identification of phototoxic potential of new drug entities in drug discovery and development. Current drug safety. 2009;4:123-36. Onoue S, Tsuda Y. Analytical studies on the prediction of photosensitive/phototoxic potential of pharmaceutical substances. Pharmaceutical research. 2006;23:156-64. Ozcan, Ayla, and Metin Ogun. 2015. “Biochemistry of Reactive Oxygen and Nitrogen Species.” In Basic Principles and Clinical Significance of Oxidative Stress, edited by Sivakumar Joghi Thatha Gowder. Rijeka: IntechOpen. Parrish, A. R. 2010. “2.27 - Hypoxia/Ischemia Signaling.” In Comprehensive Toxicology (Second Edition), edited by Charlene A. McQueen, 529–42. Oxford: Elsevier. PCPC. PCPC 2014 safety evaluation guidelines; Chapter 7: Evaluation of Photoirritation and Photoallergy potential. Personal Care Products Council; 2014. Ramos, M. F. P., et al. (2018). "Xanthine oxidase inhibitors and sepsis." Int J Immunopathol Pharmacol. 32:2058738418772210. doi:10.1177/2058738418772210 Ravanat, J. L., et al. (2014). "Radiation-mediated formation of complex damage to DNA: a chemical aspect overview." Br J Radiol 87(1035): 20130715. Schutzendubel, A. and Polle, A. (2002). "Plant responses to abiotic stresses: heavy metal-induced oxidative stress and protection by mycorrhization." Journal of Experimental Botany, 53(372), 1351–1365. https://doi.org/10.1093/jexbot/53.372.1351 Seto Y, Kato M, Yamada S, Onoue S. Development of micellar reactive oxygen species assay for photosafety evaluation of poorly water-soluble chemicals. Toxicology in vitro : an international journal published in association with BIBRA. 2013;27:1838-46. Sharma, Gunjan, Nishant Kumar Rana, Priya Singh, Pradeep Dubey, Daya Shankar Pandey, and Biplob Koch. 2017. “p53 Dependent Apoptosis and Cell Cycle Delay Induced by Heteroleptic Complexes in Human Cervical Cancer Cells.” Biomedicine & Pharmacotherapy = Biomedecine & Pharmacotherapie 88 (April): 218–31. Silva, R., et al. (2019). "Light exposure during growth increases riboflavin production, reactive oxygen species accumulation and DNA damage in Ashbya gossypii riboflavin-overproducing strains." FEMS Yeast Research, 19(1), 1–7. https://doi.org/10.1093/femsyr/foy114 Tsuchiya K, et al. (2005). "Oxygen radicals photo-induced by ferric nitrilotriacetate complex." Biochim Biophys Acta. 1725(1):111-9. doi:10.1016/j.bbagen.2005.05.001 Wang, J., et al. (2017). "Glucocorticoids Suppress Antimicrobial Autophagy and Nitric Oxide Production and Facilitate Mycobacterial Survival in Macrophages." Scientific reports, 7(1), 982. https://doi.org/10.1038/s41598-017-01174-9 Wang, X., et al. (2013). "Imaging ROS signaling in cells and animals." Journal of molecular medicine 91(8): 917-927. Yen, Cheng Chien, et al. "Inorganic arsenic causes cell apoptosis in mouse cerebrum through an oxidative stress-regulated signaling pathway." Archives of toxicology 85 (2011): 565-575. Yuan, Yan, et al. "Cadmium-induced apoptosis in primary rat cerebral cortical neurons culture is mediated by a calcium signaling pathway." PloS one 8.5 (2013): e64330. Zhang, Z., et al. (2011). "Reactive oxygen species mediate arsenic induced cell transformation and tumorigenesis through Wnt/β-catenin pathway in human colorectal adenocarcinoma DLD1 cells. " Toxicology and Applied Pharmacology, 256(2), 114-121. doi:10.1016/j.taap.2011.07.016 AOPWiki 2016-11-29T18:41:29

2025-06-12T01:27:08

modulation, Extracellular Matrix Composition

Cellular

Collagen is a structural protein in the supramolecular structure of the extracellular matrix (ECM). The expression of COL3A1 is closely associated with the remodelling of the ECM [1]. Meanwhile, integrin receptors serve as the primary molecular link between cells and the ECM, mediating intercellular interactions [2]. Hepatic fibrosis is characterized by excessive deposition of ECM proteins [3].

Histochemical Staining and Morphometric Analysis

Collagen-mediated extracellular matrix assembly is known to be highly conserved throughout metazoan evolution and is evolutionarily ubiquitous from humans to lower invertebrates [4].

CL:0000255

CL eukaryotic cell

Not Specified Unspecific

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1. Xu, R., Yang, E., Liang, H., Luo, S., Liu, Y., Khoong, Y., . . . Zan, T. (2024). ALKBH5‐mediated m6A demethylation ameliorates extracellular matrix deposition in cutaneous pathological fibrosis. Clinical and Translational Medicine, 14(9). doi:10.1002/ctm2.70016 2. Chastney, M. R., Kaivola, J., Leppänen, V.-M., & Ivaska, J. (2024). The role and regulation of integrins in cell migration and invasion. Nature Reviews Molecular Cell Biology, 26(2), 147-167. doi:10.1038/s41580-024-00777-1 3. Akkız, H., Gieseler, R. K., & Canbay, A. (2024). Liver Fibrosis: From Basic Science towards Clinical Progress, Focusing on the Central Role of Hepatic Stellate Cells. International Journal of Molecular Sciences, 25(14). doi:10.3390/ijms25147873 4. Exposito JY, Cluzel C, Garrone R, Lethias C. Evolution of collagens. Anat Rec. 2002 Nov 1;268(3):302-16. doi: 10.1002/ar.10162. PMID: 12382326. AOPWiki 2016-11-29T18:41:30

2026-06-04T02:24:03

Necrosis

Tissue

Not Specified Unspecific

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AOPWiki 2017-02-07T13:22:14

2017-02-07T13:22:14

Pyroptosis

Cellular

Pyroptosis is an inflammatory form of programmed cell death. Pore-forming protein gasdermins (GSDM) are crucial factors for pyroptosis execution whereby GSDMD and GSDME are most deeply studied [1]. Pyroptosis is initiated through inflammasome activation resulting to activation of caspase-1 (CASP1). Active CASP1 cleaves GSDMD, and also cleaves and thus activates pro-inflammatory cytokines interleukin-1B (IL1B) and IL18 [2]. N-terminal cleaved domain of GSDMD forms pores in the plasma membrane leading to cell swelling and pyroptotic cell death [3, 4]. IL1B and IL18 are released through the pores contributing to inflammatory and pyroptotic processes.

A common way to measure pyroptosis is through enzymatic assays for detection of lactate hydrogenase (LDH). LDH is released when plasma membrane is damaged and is a common measure of cytotoxicity. LDH release assays using commercially available kit and a quick, cost-effective method adapted from Decker et al [8] are described by Rayamajhi and colleagues [9]. Den Hartigh and Fink also describe LDH release assay as well as fluorescent microscopy method for visualization of loss of membrane integrity during pyroptosis [10]. Pyroptosis initiation can be inferred from CASP1 activation hence the CASP1 Fluorescein Assay (FLICA) is also used by researchers as detection method [11, 12]. Furthermore, Hoechst 33342 (chromatin condensation detection) and propidium iodide (probe for membrane damage) double staining can be used for pyroptotic cell detection although this method also detects other cell death types (e.g. apoptotis) [11, 13].

1. Yu, P., et al., Pyroptosis: mechanisms and diseases. Signal Transduct Target Ther, 2021. 6(1): p. 128.  2. Kelley, N., et al., The NLRP3 Inflammasome: An Overview of Mechanisms of Activation and Regulation. Int J Mol Sci, 2019. 20(13).  3. He, W.T., et al., Gasdermin D is an executor of pyroptosis and required for interleukin-1β secretion. Cell Res, 2015. 25(12): p. 1285-98.  4. Sborgi, L., et al., GSDMD membrane pore formation constitutes the mechanism of pyroptotic cell death. Embo j, 2016. 35(16): p. 1766-78.  5. Farag, N.S., et al., Viroporins and inflammasomes: A key to understand virus-induced inflammation. Int J Biochem Cell Biol, 2020. 122: p. 105738.  6. Shah, A., Novel Coronavirus-Induced NLRP3 Inflammasome Activation: A Potential Drug Target in the Treatment of COVID-19. Front Immunol, 2020. 11: p. 1021.  7. Xu, H., et al., SARS-CoV-2 viroporin triggers the NLRP3 inflammatory pathway. bioRxiv, 2020: p. 2020.10.27.357731.  8. Decker, T. and M.L. Lohmann-Matthes, A quick and simple method for the quantitation of lactate dehydrogenase release in measurements of cellular cytotoxicity and tumor necrosis factor (TNF) activity. J Immunol Methods, 1988. 115(1): p. 61-9.  9. Rayamajhi, M., Y. Zhang, and E.A. Miao, Detection of pyroptosis by measuring released lactate dehydrogenase activity. Methods Mol Biol, 2013. 1040: p. 85-90.  10. den Hartigh, A.B. and S.L. Fink, Pyroptosis Induction and Detection. Curr Protoc Immunol, 2018. 122(1): p. e52.  11. Chen, A., et al., Rosuvastatin protects against coronary microembolization-induced cardiac injury via inhibiting NLRP3 inflammasome activation. Cell Death Dis, 2021. 12(1): p. 78.  12. Wang, Y., et al., Caspase-1-Dependent Pyroptosis of Peripheral Blood Mononuclear Cells Is Associated with the Severity and Mortality of Septic Patients. Biomed Res Int, 2020. 2020: p. 9152140.  13. Chen, A., et al., Liraglutide attenuates NLRP3 inflammasome-dependent pyroptosis via regulating SIRT1/NOX4/ROS pathway in H9c2 cells. Biochem Biophys Res Commun, 2018. 499(2): p. 267-272.  AOPWiki 2022-01-18T03:05:05

2022-01-19T05:03:39

Apoptosis

Cellular

Apoptosis, the process of programmed cell death, is characterized by distinct morphology with DNA fragmentation and energy dependency [Elmore, 2007]. Apoptosis, also called “physiological cell death”, is involved in cell turnover, physiological involution, and atrophy of various tissues and organs [Kerr et al., 1972]. The formation of apoptotic bodies involves marked condensation of both nucleus and cytoplasm, nuclear fragmentation, and separation of protuberances [Kerr et al., 1972]. Apoptosis is characterized by DNA ladder and chromatin condensation. Several stimuli such as hypoxia, nucleotides deprivation, chemotherapeutical drugs, DNA damage, and mitotic spindle damage induce p53 activation, leading to p21 activation and cell cycle arrest [Pucci et al., 2000]. The SAHA or TSA treatment on neonatal human dermal fibroblasts (NHDFs) for 24 or 72 hrs inhibited proliferation of the NHDF cells [Glaser et al., 2003]. Considering that the acetylation of histone H4 was increased by the treatment of SAHA for 4 hrs, histone deacetylase inhibition may be involved in the inhibition of the cell proliferation [Glaser et al., 2003]. The impaired proliferation was observed in HDAC1-/- ES cells, which was rescued with the reintroduction of HDAC1 [Zupkovitz et al., 2010]. An AOP focuses existes on p21 pathway leading to apoptosis, however, alternative pathways such as NF-kappaB signaling pathways may be involved in the apoptosis of spermatocytes [Wang et al., 2017]. Apoptosis is defined as a programmed cell death.  A decrease in apoptosis or a resistance to cell death is noted is described as a hallmark of cancer by Hanahan et al. It is widely admitted as an essential step in tumor proliferation (Adams, Lowe).  Apoptosis occurs after activation of a number of intrinsic and extrinsic signals which activate the protease caspase system which in turn activates the destruction of the cell.    In mammals, the foetal ovary produces hundreds of thousands of oocytes. But most of them die before birth due to apoptosis (Kaur, S., & Kurokawa, M., 2023). The apoptotic process has a specific pattern at different stages: in foetal ovaries, the majority of apoptotic activity was found in germ cells, whereas in adult quiescent cortical follicles, apoptosis occurred from both granulosa and oocyte cells. The oocyte has been shown to be the one that triggers the apoptotic process and causes follicular atresia (Jin, X., et al. (2011). In humans, the primordial follicles' ovarian endowment is formed throughout foetal development. Apoptotic cell death, which is carried out with the assistance of multiple players and routes conserved from worms to humans, depletes this endowment by at least two-thirds prior to birth. As of right now, apoptosis has been linked to atresia, oocyte loss/selection, folliculogenesis, and oogenesis (Hussein MR, 2005) The Bcl-2 is a protein family suppressing apoptosis by binding and inhibiting two proapoptotic proteins (Bax and Bak) and transferring them to the mitochondrial outer membrane. In the absence of inhibition by Bcl2, Bax and Bak destroy the mitochondrial membrane and releases proapoptotic signaling proteins, such as cytochrome c which activated the caspase system. An increased expression of these antiapoptotic proteins (Bcl-2, Bcl-xL) occurs in cancer (Hanahan, Adams, Lowe). Several others pathways such as the loss of TP53 tumor suppressor function, or the increase of survival signals (Igf1/2), or decrease of proapoptotic factors (Bax, Bim, Puma) can also increase tumor growth (Hanahan, Juntilla). In breast cancer a decrease in apoptosis and a resistance to cell death has been described thoroughly, especially using a dysregulation of the Bcl2 system or TP53 (Parton, Williams, Shahbandi).

Apoptosis is characterized by many morphological and biochemical changes such as homogenous condensation of chromatin to one side or the periphery of the nuclei, membrane blebbing and formation of apoptotic bodies with fragmented nuclei, DNA fragmentation, enzymatic activation of pro-caspases, or phosphatidylserine translocation that can be measured using electron and cytochemical optical microscopy, proteomic and genomic methods, and spectroscopic techniques [Archana et al., 2013; Martinez et al., 2010; Taatjes et al., 2008; Yasuhara et al., 2003]. ・DNA fragmentation can be quantified with comet assay using electrophoresis, where the tail length, head size, tail intensity, and head intensity of the comet are measured [Yasuhara et al., 2003]. ・The apoptosis is detected with the expression alteration of procaspases 7 and 3 by Western blotting using antibodies [Parajuli et al., 2014]. ・The apoptosis is measured with down-regulation of anti-apoptotic gene baculoviral inhibitor of apoptosis protein repeat containing 2 (BIRC2, or cIAP1) [Parajuli et al., 2014]. ・Apoptotic nucleosomes are detected using Cell Death Detection ELISA kit, which was calculated as absorbance subtraction at 405 nm and 490 nm [Parajuli et al., 2014]. ・Cleavage of PARP is detected with Western blotting [Parajuli et al., 2014]. ・Caspase-3 and caspase-9 activity is measured with the enzyme-catalyzed release of p-nitroanilide (pNA) and quantified at 405 nm [Wu et al., 2016]. ・Apoptosis is measured with Annexin V-FITC probes, and the relative percentage of Annexin V-FITC-positive/PI-negative cells is analyzed by flow cytometry [Wu et al., 2016]. ・Apoptosis is detected with the Terminal dUTP Nick End-Labeling (TUNEL) method to assay the endonuclease cleavage products by enzymatically end-labeling the DNA strand breaks [Kressel and Groscurth, 1994]. ・For the detection of apoptosis, the testes are fixed in neutral buffered formalin and embedded in paraffin. Germ cell death is visualized in testis sections by Terminal dUTP Nick End-Labeling (TUNEL) staining method [Wade et al., 2008]. The incidence of TUNEL-positive cells is expressed as the number of positive cells per tubule examined for one entire testis section per animal [Wade et al., 2008]

・Apoptosis is induced in human prostate cancer cell lines (Homo sapiens) [Parajuli et al., 2014]. ・Apoptosis occurs in B6C3F1 mouse (Mus musculus) [Elmore, 2007]. ・Apoptosis occurs in Sprague-Dawley rat (Rattus norvegicus) [Elmore, 2007]. ・Apoptosis occurs in the nematode (Caenorhabditis elegans) [Elmore, 2007]. <ul> <li>Apoptosis occurs in breast cancer cells, human and mouse (Parton)</li> <li style="text-align:justify">Apoptosis applicable to fishes, hence be used to study as models (dos Santos, N. M., et al. (2008).</li> <li style="text-align:justify">Apoptosis in humans and baboon ovaries (Kugu, K., et al. (1998)</li> <li style="text-align:justify">Apoptosis in amphibians during metamorphosis (Ishizuya-Oka, A., et al. (2010).</li> <li style="text-align:justify">Apoptosis in Drosophila melanogaster (Steller, H. (2008)</li> <li style="text-align:justify">Apoptosis is a highly conserved and essential process across a broad taxonomic range, from unicellular eukaryotes to complex multicellular animals, it is also evident in metazoans (Suraweera, C. D., et al. (2022).</li> <li> Sex Applicability: Both sexes. Apoptosis occurs in male and female systems (e.g., oocyte and sperm cell turnover). </li> <li> Life Stage Applicability: All stages. Especially critical during embryonic development and in maintaining adult tissue homeostasis. </li> </ul>

UBERON:0000062

UBERON organ

CL:0000000

CL cell

High Unspecific

High

Not Otherwise Specified

High High High High

Archana, M. et al. (2013), "Various methods available for detection of apoptotic cells", Indian J Cancer 50:274-283 Elmore, S. (2007), "Apoptosis: a review of programmed cell death", Toxicol Pathol 35:495-516 Glaser, K.B. et al. (2003), "Gene expression profiling of multiple histone deacetylase (HDAC) inhibitors: defining a common gene set produced by HDAC inhibition in T24 and MDA carcinoma cell lines", Mol Cancer Ther 2:151-163 Kerr, J.F.R. et al. (1972), "Apoptosis: a basic biological phenomenon with wide-ranging implications in tissue kinetics", Br J Cancer 26:239-257 Kressel, M. and Groscurth, P. (1994), "Distinction of apoptotic and necrotic cell death by in situ labelling of fragmented DNA", Cell Tissue Res 278:549-556 Martinez, M.M. et al. (2010), "Detection of apoptosis: A review of conventioinal and novel techniques", Anal Methods 2:996-1004 Parajuli, K.R. et al. (2014), "Methoxyacetic acid suppresses prostate cancer cell growth by inducing growth arrest and apoptosis", Am J Clin Exp Urol 2:300-313 Pucci, B. et al. (2000), "Cell cycle and apoptosis", Neoplasia 2:291-299 Taatjes, D.J. et al. (2008), "Morphological and cytochemical determination of cell death by apoptosis", Histochem Cell Biol 129:33-43 Wade, M.G. et al. (2008), "Methoxyacetic acid-induced spermatocyte death is associated with histone hyperacetylation in rats", Biol Reprod 78:822-831 Wang, C. et al. (2017), "CD147 regulates extrinsic apoptosis in spermatocytes by modulating NFkB signaling pathways", Oncotarget 8:3132-3143 Wu, R. et al. (2016), "microRNA-497 induces apoptosis and suppressed proliferation via the Bcl-2/Bax-caspase9-caspase 3 pathway and cyclin D2 protein in HUVECs", PLoS One 11:e0167052 Yasuhara, S. et al. (2003), "Comparison of comet assay, electron microscopy, and flow cytometry for detection of apoptosis", J Histochem Cytochem 51:873-885 Zupkovitz, G. et al. (2010), "The cyclin-dependent kinase inhibitor p21 is a crucial target for histone deacetylase 1 as a regulator of cellular proliferation", Mol Cell Biol 30:1171-1181   Hanahan D, Weinberg RA. Hallmarks of cancer: the next generation. Cell. 2011 Mar 4;144(5):646-74. doi: 10.1016/j.cell.2011.02.013. PMID: 21376230 Adams JM, Cory S. The Bcl-2 apoptotic switch in cancer development and therapy. Oncogene. 2007 Feb 26;26(9):1324-37. doi: 10.1038/sj.onc.1210220. PMID: 17322918; PMCID: PMC2930981. Lowe, S., Cepero, E. & Evan, G. Intrinsic tumour suppression. Nature 432, 307–315 (2004). <a href="https://doi.org/10.1038/nature03098" style="color:#467886; text-decoration:underline">https://doi.org/10.1038/nature03098</a> Parton M, Dowsett M, Smith I. Studies of apoptosis in breast cancer. BMJ. 2001 Jun 23;322(7301):1528-32. doi: 10.1136/bmj.322.7301.1528. PMID: 11420276; PMCID: PMC1120573. Junttila MR, Evan GI. p53--a Jack of all trades but master of none. Nat Rev Cancer. 2009 Nov;9(11):821-9. doi: 10.1038/nrc2728. Epub 2009 Sep 24. PMID: 19776747. Williams MM, Cook RS. Bcl-2 family proteins in breast development and cancer: could Mcl-1 targeting overcome therapeutic resistance? Oncotarget. 2015 Feb 28;6(6):3519-30. doi: 10.18632/oncotarget.2792. PMID: 25784482; PMCID: PMC4414133. Shahbandi A, Nguyen HD, Jackson JG. TP53 Mutations and Outcomes in Breast Cancer: Reading beyond the Headlines. Trends Cancer. 2020 Feb;6(2):98-110. doi: 10.1016/j.trecan.2020.01.007. Epub 2020 Feb 5. PMID: 32061310; PMCID: PMC7931175. Hanahan D, Weinberg RA. Hallmarks of cancer: the next generation. Cell. 2011 Mar 4;144(5):646-74. doi: 10.1016/j.cell.2011.02.013. PMID: 21376230 Adams JM, Cory S. The Bcl-2 apoptotic switch in cancer development and therapy. Oncogene. 2007 Feb 26;26(9):1324-37. doi: 10.1038/sj.onc.1210220. PMID: 17322918; PMCID: PMC2930981. Lowe, S., Cepero, E. & Evan, G. Intrinsic tumour suppression. Nature 432, 307–315 (2004). <a href="https://doi.org/10.1038/nature03098" style="color:#467886; text-decoration:underline">https://doi.org/10.1038/nature03098</a> Parton M, Dowsett M, Smith I. Studies of apoptosis in breast cancer. BMJ. 2001 Jun 23;322(7301):1528-32. doi: 10.1136/bmj.322.7301.1528. PMID: 11420276; PMCID: PMC1120573. Junttila MR, Evan GI. p53--a Jack of all trades but master of none. Nat Rev Cancer. 2009 Nov;9(11):821-9. doi: 10.1038/nrc2728. Epub 2009 Sep 24. PMID: 19776747. Williams MM, Cook RS. Bcl-2 family proteins in breast development and cancer: could Mcl-1 targeting overcome therapeutic resistance? Oncotarget. 2015 Feb 28;6(6):3519-30. doi: 10.18632/oncotarget.2792. PMID: 25784482; PMCID: PMC4414133. Shahbandi A, Nguyen HD, Jackson JG. TP53 Mutations and Outcomes in Breast Cancer: Reading beyond the Headlines. Trends Cancer. 2020 Feb;6(2):98-110. doi: 10.1016/j.trecan.2020.01.007. Epub 2020 Feb 5. PMID: 32061310; PMCID: PMC7931175.   Parton M, Dowsett M, Smith I. Studies of apoptosis in breast cancer. BMJ. 2001 Jun 23;322(7301):1528-32. doi: 10.1136/bmj.322.7301.1528. PMID: 11420276; PMCID: PMC1120573.   <ul> <li>Kaur S, Kurokawa M. Regulation of Oocyte Apoptosis: A View from Gene Knockout Mice. Int J Mol Sci. 2023;24(2).</li> <li>Jin X, Xiao LJ, Zhang XS, Liu YX. Apotosis in ovary. Front Biosci (Schol Ed). 2011;3(2):680-97.</li> <li>Hussein MR. Apoptosis in the ovary: molecular mechanisms. Hum Reprod Update. 2005;11(2):162-77.</li> <li>dos Santos NM, do Vale A, Reis MI, Silva MT. Fish and apoptosis: molecules and pathways. Curr Pharm Des. 2008;14(2):148-69.</li> <li>Kugu K, Ratts VS, Piquette GN, Tilly KI, Tao XJ, Martimbeau S, et al. Analysis of apoptosis and expression of bcl-2 gene family members in the human and baboon ovary. Cell Death Differ. 1998;5(1):67-76.</li> <li>Ishizuya-Oka A, Hasebe T, Shi YB. Apoptosis in amphibian organs during metamorphosis. Apoptosis. 2010;15(3):350-64.</li> <li>Steller H. Regulation of apoptosis in Drosophila. Cell Death & Differentiation. 2008;15(7):1132-8.</li> <li>Suraweera CD, Banjara S, Hinds MG, Kvansakul M. Metazoans and Intrinsic Apoptosis: An Evolutionary Analysis of the Bcl-2 Family. International Journal of Molecular Sciences. 2022;23(7):3691.</li> </ul> AOPWiki 2017-02-07T13:21:50

2025-05-31T08:50:09

Activation of inflammation pathway

Activation, inflammation pathway

Cellular

AOPWiki 2022-05-31T02:47:29

2022-05-31T02:47:29

Increase, Cell Proliferation

Cellular

Throughout their life, cells replicate their organelles and genetic information before dividing to form two new daughter cells, in a process known as cellular proliferation. This replicative process is known as the cell cycle and is subdivided into various stages notably, G1, S, G2, and M in mammals. G1 and G2 are gap phases, separating mitosis and DNA synthesis. Differentiated cells typically remain in G1; however, quiescent cells reside in an optional phase just before G1, known as G0.   Progression through the cycle is dependent on sufficient nutrient availability to provide optimal nucleic acid, protein, and lipid levels, as well as sufficient cell mass. To this end, the cell cycle is mediated by three major checkpoints: the restriction (R) point, or G1/S checkpoint, controlling entry into S phase, the G2/M checkpoint, controlling entry into mitosis, and one more controlling entry into cytokinesis. If conditions are ideal for division, cells will pass the restriction point (G1/S) and begin the activation and expression of genes used for duplicating centrosomes and DNA, eventually leading to proliferation (Cuyàs et al., 2014).   Various protein complexes, known as cyclins, cyclin-dependent kinases (CDKs), and cyclin-dependent kinase inhibitors (CKIs) regulate passage through each phase by activating and inhibiting specific processes (Lovicu et al., 2014). The CDKs are responsible for controlling progression through the cell cycle. They promote DNA synthesis and mitosis, and therefore cell division (Barnum & O’Connell, 2014). Furthermore, growth factors are required to stimulate cell division, but after passing through the restriction point at G1 they are no longer necessary (Lovicu et al., 2014).   In the context of cancer, one hallmark is the sustained and uncontrolled cell proliferation (Hanahan et al., 2011, Portt et al., 2011). When cells obtain a growth advantage due to mutations in critical genes that regulate cell cycle progression, they may begin to proliferate excessively, resulting in hyperplasia and potentially leading to the development of a tumor. This is often achieved through oncogene activation and inactivation of tumor suppressor genes (Hanahan et al., 2011). Cell inactivation and the replacement of these cells can initiate clonal expansion (Heidenreich and Paretzke et al., 2008).  Sustained atrophy/degeneration olfactory epithelium under the influence of a cytotoxic agent leads to adaptive tissue remodeling. Cell types unique to olfactory epithelium, e.g. olfactory neurons, sustentacular cells and Bowmans glands, are replaced by cell types comprising respiratory epithelium or squamous epithelium.

Two common methods of measuring cell proliferation in vivo are the use of Bromodeoxyuridine (5-bromo-2'-deoxyuridine, BrdU) labeling (Pera, 1977), and Ki67 immunostaining (Grogan, 1988). BrdU is a synthetic analogue of the nucleoside Thymidine. BrDu is incorporated into DNA synthesized during the S1 phase of cell replication and is stable for long periods. Labeling of dividing cells by BrdU is accomplished by infusion, bolus injection, or implantation of osmotic pumps containing BrdU for a period of time sufficient to generate measureable numbers of labeled cells. Tissue sections are stained immunhistochemically with antibodies for BrdU and labeled cells are counted as dividing cells. Similarly, 5-iodo-2'-deoxyuridine (IdU) is another analogue of thymidine used to measure cell proliferation as it is also incorporated into DNA during its synthesis (Devine & Behbehani, 2021). Ki67 is a cellular marker of replication not found in quiescent cells (Roche, 2015). Direct immunohistochemical staining of cells for protein Ki67 using antibodies is an alternative to the use of BrdU, with the benefit of not requiring a separate treatment (injection for pulse-labeling). Cells positive for Ki67 are counted as replicating cells. Replicating cell number is reported per unit tissue area or per cell nuclei (Bogdanffy, 1997). Listed below are common methods for detecting the KE, however there may be other comparable methods that are not listed. <table border="1" cellpadding="1" cellspacing="1" style="height:298px; width:595px"> <tbody> <tr> <td style="background-color:#dddddd; text-align:center">Assay Name</td> <td style="background-color:#dddddd; text-align:center">References</td> <td style="background-color:#dddddd; text-align:center">Description</td> <td style="background-color:#dddddd; text-align:center">OECD Approved Assay</td> </tr> <tr> <td>CyQuant Cell Proliferation Assay</td> <td>Jones et al., 2001</td> <td>DNA-binding dye is added to cell cultures, and the dye signal is measured directly to provide a cell count and thus an indication of cellular proliferation</td> <td>N/A</td> </tr> <tr> <td>Nucleotide Analog Incorporation Assays (e.g. BrdU, EdU)</td> <td>Romar et al., 2016, Roche; 2013</td> <td>Nucleoside analogs are added to cells in culture or injected into animals and become incorporated into the DNA at different rates, depending on the level of cellular proliferation; Antibodies conjugated to a peroxidase or fluorescent tag are used for quantification of the incorporated nucleoside analogs using techniques such as ELISA, flow cytometry, or microscopy</td> <td>Yes (No. 442B)</td> </tr> <tr> <td>Cytoplasmic Proliferation Dye Assays</td> <td>Quah & Parish, 2012</td> <td>Cells are incubated with a cytoplasmic dye of a certain fluorescent intensity; Cell divisions decrease the intensity in such a way that the number of divisions can be calculated using flow cytometry measurements</td> <td>N/A</td> </tr> <tr> <td>Colourimetric Dye Assays</td> <td>Vega-Avila & Pugsley, 2011; American Type Culture Collection</td> <td>Cells are incubated with a dye that changes colour following metabolism; Colour change can be measured and extrapolated to cell number and thus provide an indication of cellular proliferation rates</td> <td>N/A</td> </tr> <tr> <td>BrdU, Ki67, IdU Quantification - Flow Cytometry </td> <td>Ligasová et al., 2017; Devine & Behehani, 2021; Kim & Sederstrom, 2015</td> <td>Measurement of cell proliferation biomarkers by flow cytometry, normalized to total levels of BrdU, Ki67 or IdU.   </td> <td>No</td> </tr> </tbody> </table>

Cell proliferation is a central process supporting development, tissue homeostasis and carcinogenesis, each of which occur in all vertebrates. This key event has been observed nasal tissues of rats exposed to the chemical initiator vinyl acetate. In general, cell proliferation is necessary in the biological development and reproduction of most organisms. This KE is thus relevant and applicable to all multicellular cell types, tissue types, and taxa. Life stage applicability: This key event is not life stage specific (Fujimichi and Hamada, 2014; Barnard et al., 2022). Sex applicability: This key event is not sex specific (Markiewicz et al., 2015). Evidence for perturbation by a stressor: There is a large body of evidence supporting the effectiveness of ionizing radiation, UV, and mechanical wounding as stressors for increased cell proliferation. These stressors can be subdivided into X-rays (van Sallmann, 1951; Ramsell and Berry, 1966; Richards, 1966; Riley et al., 1988; Riley et al., 1989; Kleiman et al., 2007; Pendergrass et al., 2010; Fujimichi and Hamada, 2014, Markiewicz et al., 2015; Bahia et al., 2018), 60Co γ-rays (Hanna and O’Brien, 1963; Barnard et al., 2022; McCarron et al., 2021), 137Cs γ-rays (Andley and Spector, 2005), neutrons (Richards, 1966; Riley et al., 1988; Riley et al., 1989), 40Ar (Worgul et al., 1986), 56Fe (Riley et al., 1989), UVB (Söderberg et al., 1986; Andley et al., 1994; Cheng et al., 2019), UVC (Trenton and Courtois, 1981), and mechanical wounding (Riley et al., 1989).

High Unspecific

High

All life stages

High High High

Andley, U. P. et al. (1994), “Modulation of lens epithelial cell proliferation by enhanced prostaglandin synthesis after UVB exposure”, Investigative Ophthalmology & Visual Science, Vol. 35/2, Rockville, pp. 374-381   Andley, U. and A. Spector (2005), “Peroxide resistance in human and mouse lens epithelial cell lines is related to long-term changes in cell biology and architecture”, Free Radical Biology & Medicine, Vol. 39/6, Elsevier B.V, United States, https://doi.org/10.1016/j.freeradbiomed.2005.04.028  Bahia, S. et al. (2018), “Oxidative and nitrative stress-related changes in human lens epithelial cells following exposure to X-rays”, International journal of radiation biology, Vol. 94/4, England, <a href="https://doi.org/10.1080/09553002.2018.1439194" rel="noreferrer noopener" target="_blank">https://doi.org/10.1080/09553002.2018.1439194</a>  Barnard, S. et al. (2022), “Lens Epithelial Cell Proliferation in Response to Ionizing Radiation.”, Radiation Research, Vol. 197/1, Radiation Research Society, United States, <a href="https://doi.org/10.1667/RADE-20-00294.1" rel="noreferrer noopener" target="_blank">https://doi.org/10.1667/RADE-20-00294.1</a>  Barnum, K. and M. O’Connell (2014), “Cell cycle regulation by checkpoints”, in Cell cycle control, Springer, New York, http://doi.org/ 10.1007/978-1-4939-0888-2  Bogdanffy. et al. (1997). “FOUR-WEEK INHALATION CELL PROLIFERATION STUDY OF THE EFFECTS OF VINYL ACETATE ON RAT NASAL EPITHELIUM”, Inhalation Toxicology, Taylor & Francis. 9: 331-350. Cheng, T. et al. (2019), “lncRNA H19 contributes to oxidative damage repair in the early age-related cataract by regulating miR-29a/TDG axis”, Journal of cellular and molecular medicine, Vol. 23/9, Wiley Subscription Services, Inc. England, https://doi.org/10.1111/jcmm.14489  Cuyàs, E. et al. (2014), “Cell cycle regulation by the nutrient-sensing mammalian target of rapamycin (mTOR) pathway”, in Cell cycle control, Springer, New York, http://dx.doi.org/ 10.1007/978-1-4939-0888-2  Devine,R. D, and G. K. Behbehani (2021), “Use of the Pyrimidine Analog, 5-Iodo-2'-Deoxyuridine (IdU) with Cell Cycle Markers to establish Cell Cycle Phases in a Mass Cytometry Platform”, Journal of visualized experiments. (176). doi:10.3791/60556   Fujimichi, Y. and N. Hamada (2014), “Ionizing irradiation not only inactivates clonogenic potential in primary normal human diploid lens epithelial cells but also stimulates cell proliferation in a subset of this population”, PloS one, Vol. 9/5, e98154, Public Library of Science, United States, <a href="https://doi.org/10.1371/journal.pone.0098154" rel="noreferrer noopener" target="_blank">https://doi.org/10.1371/journal.pone.0098154</a>  Grogan. et al. (1988). “Independent prognostic significance of a nuclear proliferation antigen in diffuse large cell lymphomas as determined by the monoclonal antibody Ki-67”, Blood. 71: 1157-1160. Hanna, C. and J. E. O’Brien (1963), “Lens epithelial cell proliferation and migration in radiation cataracts”, Radiation research, Academic Press, Inc, United States, <a href="https://doi.org/10.2307/3571405" rel="noreferrer noopener" target="_blank">https://doi.org/10.2307/3571405</a>  Hanahan, D. & R. A. Weinberg, (2011),” Hallmarks of cancer: the next generation”, Cell. 144(5):646-74. doi: 10.1016/j.cell.2011.02.013. Heidenreich WF, Paretzke HG. (2008) Promotion of initiated cells by radiation-induced cell inactivation. Radiat Res. Nov;170(5):613-7. doi: 10.1667/RR0957.1. PMID: 18959457. Jones, J. L. et al. (2001), Sensitive determination of cell number using the CyQUANT cell proliferation assay. Journal of Immunological Methods. 254(1-2), 85-98. Doi:10.1016/s0022-1759(01)00404-5. Kim, K. H. and Sederstrom J. M. (2015), “Assaying Cell Cycle Status Using Flow Cytometry.” Current protocols in molecular biology, 111:28.6.1-28.6.11., doi:10.1002/0471142727.mb2806s111   Kleiman, N. J. et al. (2007), “Mrad9 and Atm haplinsufficiency enhance spontaneous and X-ray-induced cataractogenesis in mice”, Radiation research, Vol. 168/5, Radiation Research Society, United States, <a href="https://doi.org/10.1667/rr1122.1" rel="noreferrer noopener" target="_blank">https://doi.org/10.1667/rr1122.1</a>  Ligasová, A. et al. (2017), “Cell cycle profiling by image and flow cytometry: The optimised protocol for the detection of replicational activity using 5-Bromo-2'-deoxyuridine, low concentration of hydrochloric acid and exonuclease III.” PloS one, 12(4): e0175880, doi:10.1371/journal.pone.0175880   Lovicu, J. et al (2014), “Lens epithelial cell proliferation”, in Lens epithelium and posterior capsular opacification, Springer, Tokyo, http://dx.doi.org/ 10.1007/978-4-431-54300-8_4  Markiewicz, E. et al. (2015), “Nonlinear ionizing radiation-induced changes in eye lens cell proliferation, cyclin K1 expression and lens shape”, Open biology, Vol. 5/4, The Royal Society, England, <a href="https://doi.org/10.1098/rsob.150011" rel="noreferrer noopener" target="_blank">https://doi.org/10.1098/rsob.150011</a>  McCarron, R. A. et al. (2021), “Radiation-induced lens opacity and cataractogenesis: a lifetime study using mice of varying genetic backgrounds”, Radiation research, Vol. 197/1, Radiation Research Society, United States, https://doi.org/10.1667/RADE-20-00266.1  Pendergrass, W. et al. (2010), “X-ray induced cataract is preceded by LEC loss, and coincident with accumulation of cortical DNA, and ROS; similarities with age-related cataracts”, Molecular vision, Vol. 16, Molecular Vision, United States, pp. 1496-1513  Pera, Mattias and Detzer (1977). “Methods for determining the proliferation kinetics of cells by means of 5-bromodeoxyuridine”, Cell Tissue Kinet.10: 255-264. Doi: 10.1111/j.1365-2184.1977.tb00293.x. Portt, L. et al. (2011), “Anti-apoptosis and cell survival: a review”, Biochim Biophys Acta. 21813(1):238-59. doi: 10.1016/j.bbamcr.2010.10.010. Quah, J. C. B. & R. C. Parish (2012), “New and improved methods for measuring lymphocyte proliferation in vitro and in vivo using CFSE-like fluorescent dyes”, Journal of Immunological Methods. 379(1-2), 1-14. doi: 10.1016/j.jim.2012.02.012. Ramsell, T. G. and R. J. Berry (1966), “Recovery from X-ray damage to the lens. The effects of fractionated X-ray doses observed in rabbit lens epithelium irradiated in vivo”, British Journal of Radiology, Vol. 39/467, England, pp. 853-858  Riley, E. F. et al. (1988), “Recovery of murine lens epithelial cells from single and fractionated doses of X rays and neutrons”, Radiation Research, Vol. 114/3, Academic Press Inc, Oak Brook, https://doi.org/10.2307/3577127  Riley, E. F. et al. (1989), “Comparison of recovery from potential mitotic abnormality in mitotically quiescent lens cells after X, neutron, and 56Fe irradiations”, Radiation Research, Vol. 119/2, United States, pp. 232-254  Richards, R. D. (1966), “Changes in lens epithelium after X-ray or neutron irradiation (mouse and rabbit)”, Transactions of the American Ophthalmological Society, Vol. 64, United States, pp. 700-734  Roche Applied Science, (2013), “Cell Proliferation Elisa, BrdU (Colourmetric) ». Version 16 Romar, A. G., S. T. Kupper & J. S. Divito (2015), “Research Techniques Made Simple: Techniques to Assess Cell Proliferation”,  Journal of Investigative Dermatology. 136(1), e1-7. doi: 10.1016/j.jid.2015.11.020. Söderberg, P. G. et al. (1986), “Unscheduled DNA synthesis in lens epithelium after in vivo exposure to UV radiation in the 300 nm wavelength region”, Acta Ophthalmologica, Vol. 64/2, Blackwell Publishing Ltd, Oxford, UK, https://doi.org/10.1111/j.1755-3768.1986.tb06894.x  Trenton, J. A. and Y. Courtois (1981), “Evolution of the distribution, proliferation and ultraviolet repair capacity of rat lens epithelial cells as a function of maturation and aging”, Mechanisms of Ageing and Development, Vol. 15/3, Elsevier, Ireland, https://doi.org/1016/0047-6374(81)90134-2  Vega-Avila, E. & K. M. Pugsley (2011), “An Overview of Colorimetric Assay Methods Used to Assess Survival or Proliferation of Mammalian Cells”, Proc. West. Pharmacol. Soc. 54, 10-4. von Sallmann, L. (1951), “Experimental studies on early lens changes after x-ray irradiation III. Effect of X-radiation on mitotic activity and nuclear fragmentation of lens epithelium in normal and cysteine-treated rabbits”, Transactions of the American Ophthalmological Society, Vol. 48, United States, pp. 228-242  Worgul, B. V. et al. (1986), “Accelerated heavy particles and the lens II. Cytopathological changes”, Investigative Ophthalmology and Visual Science, Vol 27/1, pp. 108-114  AOPWiki 2016-11-29T18:41:27

2024-12-10T15:01:01

Increase, Liver fibrosis

Organ

Liver fibrosis results from perpetuation of the normal wound healing response, as a result of repeated cycles of hepatocyte injury and repair and is a dynamic process, characterised by an excessive deposition of ECM (extracellular matrix) proteins including glycoproteins, collagens, and proteoglycans. It is usually secondary to hepatic injury and inflammation, and progresses at different rates depending on the aetiology of liver disease and is also influenced by environmental and genetic factors. If fibrosis continues, it disrupts the normal architecture of the liver, altering the normal function of the organ and ultimately leading to liver damage. Cirrhosis represents the final stage of fibrosis. It is characterised by fibrous septa which divide the parenchyma into regenerative nodules which leads to vascular modifications and portal hypertension with its complications of variceal bleeding, hepatic encephalopathy, ascites, and hepatorenal syndrome. In addition, this condition is largely associated with hepatocellular carcinoma with a further increase in the relative mortality rate (Bataller and Brenner, 2005; Merck Manual,2015) Liver fibrosis is an important health issue with clear regulatory relevance. The burden of disease attributable to liver fibrosis is quite high; progressive hepatic fibrosis, ultimately leading to cirrhosis, is a significant contributor to global health burden (Lim and Kim, 2008). In the European Union, 0.1 % of the population is affected by cirrhosis, the most advanced stage of liver fibrosis with full architectural disturbances (Blachier et al., 2013). Besides the epidemiological relevance, liver fibrosis also imposes a considerable economic burden on society. Indeed, the only curative therapy for chronic liver failure is liver transplantation. More than 5.500 orthotopic liver transplantations are currently performed in Europe on a yearly basis, costing up to €100.000 the first year and €10.000 yearly thereafter (Van Agthoven et al., 2001).

Liver biopsy is an important part of the evaluation of patients with a variety of liver diseases. Besides establishing the diagnosis, the biopsy is often used to assess the severity of the disease. Until recently it has been assumed that fibrosis is an irreversible process, so most grading and staging systems have relatively few stages and are not very sensitive for describing changes in fibrosis. In all systems, the stages are determined by both the quantity and location of the fibrosis, with the formation of septa and nodules as major factors in the transition from one stage to the next. The absolute amount of fibrous tissue is variable within each stage, and there is considerable overlap between stages. Commonly used systems are the Knodell score with 4 stages - no fibrosis (score 0) to fibrous portal expansion (score 2) to bridging fibrosis (score 3) and Cirrhosis (score 4) – and the more sensitive Ishak fibrosis score with six stages - from no fibrosis (stage 0) over increasing fibrous expansion on portal areas (stages 1-2), bridging fibrosis (stages 3-4), and nodules (stage 5) to cirrhosis (stage 6) (Goodman, 2007). Liver biopsy is an invasive test with many possible complications and the potential for sampling error. Noninvasive tests become increasingly precise in identifying the amount of liver fibrosis through computer-assisted image analysis. Standard liver tests are of limited value in assessing the degree of fibrosis. Direct serologic markers of fibrosis include those associated with matrix deposition — e.g.procollagen type III amino-terminal peptide (P3NP), type I and IV collagens, laminin, hyaluronic acid, and chondrex. P3NP is the most widely studied marker of hepatic fibrosis. Other direct markers of fibrosis are those associated with matrix degradation, ie, matrix metalloproteinases 2 and 3 (MMP-2, MMP- 3) and tissue inhibitors of metalloproteinases 1 and 2 (TIMP-1, TIMP-2).These tests are not commercially available, and the components are not readily available in most clinical laboratories. Some indirect markers that combine several parameters are available but not very reliable. Conventional imaging studies (ultrasonography and computed tomography) are not sensitive for fibrosis. Hepatic elastography, a method for estimating liver stiffness, is a recent development in the noninvasive measurement of hepatic fibrosis. Currently, elastography can be accomplished by ultrasound or magnetic resonance. Liver biopsy is still needed if laboratory testing and imaging studies are inconclusive (Carey, 2010; Germani et al., 2011) .

Human: Bataller and Brenner, 2005;Merck Manual, 2015; Blachier et al., 2013. Rat, mouse: Liedtke et al., 2013

UBERON:0002107

UBERON liver

Not Specified Unspecific

Not Specified

All life stages

High High High

<ul> <li>Bataller, R. and D.A. Brenner (2005), Liver Fibrosis, J.Clin. Invest, vol. 115, no. 2, pp. 209-218.</li> <li>Merck Manual available at: <a class="external free" href="http://www.merckmanuals.com/professional/hepatic_and_biliary_disorders/fibrosis_and_cirrhosis/hepatic_fibrosis.html,(accessed" rel="nofollow" target="_blank">http://www.merckmanuals.com/professional/hepatic_and_biliary_disorders/fibrosis_and_cirrhosis/hepatic_fibrosis.html,(accessed</a> 10 February 2015).</li> <li>Lim, Y. and W. Kim (2008), The global impact of hepatic fibrosis and end-stage liver disease, Clin Liver Dis, vol. 12, no. 4, pp. 733-746.</li> <li>Blachier, M. et al. (2013), The burden of liver disease in Europe: a review of available epidemiological data, J Hepatol, vol. 58, no. 3, pp. 593-608.</li> <li>Van Agthoven, M. et al. (2001), A comparison of the costs and effects of liver transplantation for acute and for chronic liver failure. Transpl Int, vol. 14, no. 2, pp. 87-94.</li> <li>Goodman, Z.D. (2007), Grading and staging systems for inflammation and fibrosis in chronic liver diseases, Journal of Hepatology, vol. 47, no. 4, pp. 598-607.</li> <li>Carey, E. (2010), Noninvasive tests for liver disease, fibrosis, and cirrhosis: Is liver biopsy obsolete? Cleveland Clinic Journal of Medicine, vol. 77, no. 8, pp. 519-527.</li> <li>Germani, G. et al. (2011), Assessment of Fibrosis and Cirrhosis in Liver Biopsies, Semin Liver Dis, vol. 31, no. 1, pp. 82-90. available at <a class="external free" href="http://www.medscape.com/viewarticle/743946_2,(accessed" rel="nofollow" target="_blank">http://www.medscape.com/viewarticle/743946_2,(accessed</a> 10 February 2015).</li> <li>Liedtke, C. et al. (2013), Experimental liver fibrosis research: update on animal models, legal issues and translational aspects, Fibrogenesis Tissue Repair, vol. 6, no. 1, p. 19.</li> </ul> AOPWiki 2016-11-29T18:41:24

2026-02-11T05:35:21

Liver Cancer

Organ

Liver cancer is among the most common forms of cancer and the second leading cause of cancer death. It is more prevalent in males than females; however, prevalence has been increasing in both genders over the last two decades (Ellison, L.F., Wilkins, K. 2012). Hepatocellular carcinoma (HCC) is a primary cancer of the hepatocytes that is typically a progression from the benign hepatocellular adenoma (HCA). The most common risk factor for developing hepatocellular carcinoma is chronic liver injury and inflammation (caused by persistent infection, fatty liver disease, or chemical exposure). This disease is almost always lethal in the absence of extreme intervention measures (e.g., surgery, liver transplant).

<ul> <li>In animal models, the presence of HCA and HCC are measured histologically following the standard two-year rodent bioassay, which is conducted according to OECD Test Guideline 451 (OECD 2009).</li> <li>In humans, liver cancer is detected by abdominal CT scan followed by biopsy and pathological examination. Symptoms of liver cancer include: jaundice, abdominal pain, nausea, and liver dysfunction. Liver cancer is more common in patients with risk factors that include: viral hepatitis, non-viral hepatitis, chronic alcoholism, obesity leading to steatohepatitis, cirrhosis, and liver fluke infection (Bonder and Afdhal 2012, Paradis 2013, Venkatesh, et al. 2014).</li> </ul>

Hepatocellular carcinoma occurs in many vertebrate species including birds, fish, and mammals such as humans.

UBERON:0002107

UBERON liver

High Mixed

High

All life stages

High Bonder, A., Afdhal, N., 2012. Evaluation of liver lesions. Clin. Liver Dis. 16, 271-283. Ellison, L.F., Wilkins, K., 2012. Canadian Trends in Cancer Prevalence. Health Reports 23. OECD, 2009. OECD Guideline for the Testing of Chemicals: Carcinogenicity Studies (Test Guideline 451). Paradis, V., 2013. Histopathology of hepatocellular carcinoma. Recent Results Cancer Res. 190, 21-32. Venkatesh, S.K., Chandan, V., Roberts, L.R., 2014. Liver masses: a clinical, radiologic, and pathologic perspective. Clin. Gastroenterol. Hepatol. 12, 1414-1429.   AOPWiki 2017-05-30T14:41:22

2021-06-19T15:00:26

<upstream-id>22508f64-3270-4a26-b709-e21aef10988d</upstream-id> <downstream-id>c3cb3a65-1015-4f51-9f87-32b519b075aa</downstream-id> Collagen is a structural protein in the supramolecular structure of the extracellular matrix (ECM). The expression of COL3A1 is closely associated with the remodelling of the ECM [1]. Meanwhile, integrin receptors serve as the primary molecular link between cells and the ECM, mediating intercellular interactions [2]. Hepatic fibrosis is characterized by excessive deposition of ECM proteins [3]. Therefore, the pathological upregulation of COL3A1 structurally disrupts normal cell-matrix homeostasis via integrin-mediated signaling, directly driving the progressive and excessive deposition of the extracellular matrix.

AOPWiki 2026-03-25T08:36:27

2026-06-04T02:52:05

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AOPWiki 2026-03-25T08:36:45

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AOPWiki 2026-03-25T08:36:56

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AOPWiki 2026-03-25T08:39:35

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AOPWiki 2026-03-25T08:39:52

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AOPWiki 2026-03-25T08:41:08

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AOPWiki 2026-03-25T08:41:31

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AOPWiki 2026-03-25T08:42:05

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AOPWiki 2026-03-25T08:49:17

2026-03-25T08:49:17

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AOPWiki 2026-03-25T08:51:13

2026-03-25T08:51:13

<upstream-id>2ec391d3-7137-4f15-85aa-beb30c0179df</upstream-id> <downstream-id>9159b48b-726f-40cb-a2dd-a9327df8f549</downstream-id>

AOPWiki 2026-03-25T08:51:39

2026-03-25T08:51:39

<upstream-id>2ec391d3-7137-4f15-85aa-beb30c0179df</upstream-id> <downstream-id>ce018273-d7aa-4f66-b8c5-62c05e237a8e</downstream-id> <div> <div> ROS generation in normal cells, including neurons, occurs within homeostatic control. When ROS levels exceed the antioxidant capacity of a cell, a deleterious condition known as oxidative stress occurs (Klein and Ackerman 2003). Unchecked, excessive ROS can lead to the destruction of cellular components including lipids, protein, and DNA, and ultimately cell death via apoptosis or necrosis (Kannan and Jain 2000). </div> </div>

<div> <div> This KER was identified as part of an Environmental Protection Agency effort to represent putative AOPs from peer-reviewed literature which were heretofore unrepresented in the AOP-Wiki. The KER is referenced in publications which were cited in the originating work for the putative AOP "Activation of MEK-ERK1/2 leads to deficits in learning and cognition via ROS and apoptosis", Katherine von Stackelberg & Elizabeth Guzy & Tian Chu & Birgit Claus Henn, 2015. Exposure to Mixtures of Metals and Neurodevelopmental Outcomes: A Multidisciplinary Review Using an Adverse Outcome Pathway Framework, Risk Analysis, John Wiley & Sons, vol. 35(6), pages 971-1016, June. This evidence was assembled from a literature search relying on standard search engines such as PubMed, Web of Science, Google Scholar, Environmental Index, Scopus, Toxline, and Toxnet and the search strategy included terms related to metal mixtures, individual metals (e.g., arsenic, lead, manganese, and cadmium), neurodevelopmental health outcomes, and associated Medical Subject Headings (MeSH) terms. </div> </div>

<div> <div> Reactive oxygen species (ROS) can be derived from exogenous sources or produced in vivo; these include the superoxide anion (O 2��), the hydroxyl radical (�OH), and hydrogen  peroxide (H 2O2). ROS at low levels participate in cell signaling while higher ROS concentrations are deleterious due to the oxidation of proteins, lipids, and DNA. Additionally,  persistent ROS production compromises the cellular antioxidant defense systems and results in oxidative stress and apoptosis (337). ROS can initiate apoptosis via the  mitochondrial and death receptor pathways. In the former, ROS have been shown to induce loss of the ��m, release of mitochondrial pro-apoptotic proteins, and activation of caspase 3 (49). ROS signaling has been shown to mediate cytokine-induced apoptosis (Okouchi et al., 2007). TNF� is a pro-inflammatory cytokine produced by macrophages and is the most studied cytokine in  apoptosis and the pathophysiology of various diseases, including neurodegenerative disorders (Jackson et al., 1999). Mechanistically, the binding of TNF� to its receptor activates the NF-�B and JNK signaling pathways believed to be mediated by ROS (Okouchi et al., 2007).  A role for ROS has also been implicated in death receptor-mediated apoptosis induced by apoptosis signal-regulating kinase 1 (ASK1), an ubquitiously expressed MAP kinase kinase kinase (MAPKKK), that activates JNK and p38 MAP kinase pathways (Okouchi et al., 2007). </div> </div>

<div> <div> Free radical scavenger or antioxidant N-acetyl-L-cysteine, a thiol-containing compound, has been shown to directly reduce the levels of ROS (Aruoma et al., 1989; Kim and Sharma 2004; Poliandri et al., 2003). To confirm that Cd-induced neuronal apoptosis is indeed due to its induction of ROS generation, PC12 and SH-SY5Y cells were pretreated with NAC (5mM) for 1h, and then exposed to Cd (10 and 20μM) for 24h (Long et al., 2008). Chen et al. (2008) found that NAC dramatically blocked Cd-induced ROS generation in PC12 cells and SH-SY5Y cells.  In addition, to further quantify the protective effect of NAC on Cd-induced apoptosis via blockage of ROS in a larger cell population, they performed annexin-V-FITC and propidium iodide staining followed by flow cytometry. They found NAC alone did not affect cell viability. However, it significantly blocked Cd-induced apoptosis. Asit Rai et al. 2010 found that a metal mixture of arsenic, cadmium, and lead triggered ROS generation, reaching its peak after 1 hour of treatment.  They next investigated whether ERK1/2, JNK1/2, [Ca2+]i and ROS signaling resulted in apoptosis by reating the MM-treated astrocytes with α-tocopherol (200 μg/ml), PD98059 (10μM), BAPTA-AM (5μM), or SP600125 (10μM).  They all suppressed apoptosis suggesting that activation of ERK1/2 and JNK1/2, followed by increased [Ca2+]i and ROS generation, resulted in apoptosis in the MM-treated astrocytes. When astrocytes were exposed to H2O2 for 30 min and then incubated without H2O2 for 1–5 days, cell toxicity including apoptosis was observed (Kazuhiro et al., 2004). Furthermore, the reperfusion injury induced by Ca2+ depletion or H2O2 exposure was exacerbated by the catalase inhibitor, 3-amino-1,2,4-triazole, and the GSH synthesis inhibitors, l-buthionine-S,R-sulfoximine and xanthine, while the injury was blocked by GSH, catalase and the iron chelators, 1,10-phenanthroline and deferoxamine (Takuma et al., 1999). These findings indicate that Ca2+ reperfusion-induced apoptosis is mediated by ROS production, especially by hydroxyl radical formation (Kazuhiro et al., 2004). Exposure of cells to 5 �M iAs significantly triggered the expression of ER stress-related molecules, including: the proteins and mRNAs expression of GRP 78, CHOP, XBP-1 in a time-dependent manner (for 6–24 h) as well as the degradation of full-length (55 kDa) caspase-12 (downstream ER stress molecule). However, GRP 94 was not affected by iAs treatment. These effects of iAs-induced ER stress protein responses could be reversed by pre-treatment with NAC. Furthermore,  transfection of Neuro-2a cells with GRP 78- and CHOP-specific si-RNA, respectively, markedly reduced the protein expression levels of GRP 78 and CHOP in the cells treated with iAs and significantly attenuate the iAs-induced caspase-3, -7, and -12 activations. These results indicate that oxidative stress-mediated ER stress activation pathway is also involved in iAs-induced neuronal cell apoptosis (Tien-Hui, et al. 2014). Recent studies have shown that ROS generation induced by toxic metals (including arsenic) causes neuronal apoptosis, which is closely associated with the progression of neurodegenerative diseases (Bharathi and Jagannathan 2006; Flora et al., 2009; Gharibzadeh 2008). Okouchi et. al. (2007) found that peroxide-induced apoptosis in undifferentiated PC12 cells was mediated by an early loss of the cellular glutathione–glutathione disulfide (GSH/GSSG) redox balance that preceded an increase in Bax expression, mitochondrial-to-cytosol cytochrome c translocation, and activation of caspase 3 (Pias and Aw 2002; Pias and Aw 2002; Pias et al., 2003). Apoptosis was  ameliorated by the overexpression of mitochondrial superoxide dismutase, MnSOD (SOD2), and by pretreatment of cells with the antioxidant, N-acetyl cysteine (NAC) (23-25). As first demonstrated in mouse fibrosarcoma cells, TNF� treatment disrupts mitochondrial electron transport and  enhances ROS production (Schulze–Osthoff et al., 1992). Recent studies by Han et al. (2006) showed that modulation of the hepatocyte redox environment by ROS interfered with NF-�B signaling in TNF-induced apoptosis. Notably, cell apoptosis occurred within a certain redox window in which mild redox imbalance inhibited NF-�B activation, but not caspase activity (Okouchi et al., 2007). </div> </div>

<div> <div> ROS and/or oxidative damage can activate gene transcription and transcribed genes may be implicated in either cell survival or cell death (Klein and Ackerman 2003). The increase in reactive oxygen species at As(III) concentrations of 0.5 mg/l or more may play an apoptogenic role and/or be a consequence of events occurring during apoptosis (Rocha et al. 2011). It is generally reported that ROS cause an increase in [Ca2+]i of various cell types, which might be one of the causes for the C17.2 cells to enter apoptosis (Rocha et al. 2011). According to Hool and Corry (2007), the redox control of Ca2+ transport is due to the fact that ROS can react with the thiol groups of protein that form part of the Ca2+ transporters or channels. Alternatively, mitochondrial matrix Ca2+ overload can lead to enhanced generation of reactive oxygen species, triggering the permeability transition pore, dissipation of transmembrane mithocondrial potential, and cytochrome c release (Brookes et al., 2004). In any case, the fact that treatment with various antioxidants (vitamin E, tocopherol, and quercetin) did not rescue the cells from death by apoptosis indicates that oxidative stress was not the main cause of the observed cell death (Rocha et al. 2011). Superoxides and lipid peroxidation are increased during apoptosis induced by myriad stimuli (Bredesen 1995). However, generation of ROS may be a relatively late event, occurring after cells have embarked on a process of caspase activation (Green and Reed 1998). In this regard, attempts to study apoptosis under conditions of anoxia have demonstrated that at least some proapoptotic stimuli function in the absence or near absence of oxygen, which implies that ROSs are not the sine qua non of apoptosis (Jacobson and Raff 1995). However, ROSs can be generated under conditions of virtual anaerobiosis (Degli Esposti and McLennan 1998), and thus their role in apoptosis cannot be excluded solely on this basis (Green and Reed 1998). Okouchi et. al. (2007) found that PC12 apoptosis can be initiated by GSH/GSSG redox imbalance alone independently of ROS generation (Pias et al., 2003), suggesting that a loss of cellular  redox homeostasis is downstream of ROS signaling in neuronal cell apoptosis. </div> </div>

Moderate Unspecific Moderate

<div> <div> A.H. Poliandri, J.P. Cabilla, M.O. Velardez, C.C. Bodo, B.H. Duvilanski Cadmium induces apoptosis in anterior pituitary cells that can be reversed by treatment with antioxidants Toxicol. Appl. Pharmacol., 190 (2003), pp. 17-24 Asit Rai et al., Characterization of Developmental Neurotoxicity of As, Cd, and Pb Mixture: Synergistic Action of Metal Mixture in Glial and Neuronal Functions, Toxicological Sciences, Volume 118, Issue 2, December 2010, Pages 586–601 Bharathi, Ravid R, Jagannathan Rao KS (2006) Role of metals in neuronal apoptosis: challenges associated with neurodegeneration. Curr Alzheimer Res 3:311–326 Bredesen, Dale E. "Neural apoptosis." Annals of neurology 38.6 (1995): 839-851. Chen, Long, Lei Liu, and Shile Huang. "Cadmium activates the mitogen-activated protein kinase (MAPK) pathway via induction of reactive oxygen species and inhibition of protein phosphatases 2A and 5." Free Radical Biology and Medicine 45.7 (2008): 1035-1044. Degli Esposti, Mauro, and Holly McLennan. "Mitochondria and cells produce reactive oxygen species in virtual anaerobiosis: relevance to ceramide-induced apoptosis." FEBS letters 430.3 (1998): 338-342. Flora SJ, Bhatt K, Mehta A (2009) Arsenic moiety in gallium arsenide is responsible for neuronal apoptosis and behavioral alterations in rats. Toxicol Appl Pharmacol 240:236–244 Gharibzadeh S, Hoseini SS (2008) Arsenic exposure may be a risk factor for Alzheimer’s disease. J Neuropsychiatr Clin Neurosci 20:501 Green, Douglas R., and John C. Reed. "Mitochondria and apoptosis." science 281.5381 (1998): 1309-1312. Han D, Hanawa N, Saberi B, and Kaplowitz N. Hydrogen peroxide and redox modulation sensitize primary mouse hepatocytes to TNF-induced apoptosis. Free Rad Biol Med 41: 627–639, 2006. J. Kim, R.P. Sharma Calcium-mediated activation of c-Jun NH2-terminal kinase (JNK) and apoptosis in response to cadmium in murine macrophages Toxicol. Sci., 81 (2004), pp. 518-527 Jackson CE, Fisher RE, Hsu AP, Anderson SM, Choi YN, Wang J, Dale JK, Fleisher TA, Middelton LA, Sneller MC, Leonardo MJ, Straus SE, and Puck JM. Autoimmune lymphoproliferative syndrome with defective Fas: genotype influences penetrance. Am J Hum Genet 64: 1002–1014, 1999 Jacobson, Michael D., and Martin C. Raff. "Programmed cell death and Bcl-2 protection in very low oxygen." Nature 374.6525 (1995): 814-816. K. Takuma, E. Lee, M. Kidawara, K. Mori, Y. Kimura, A. Baba, T. Matsuda Apoptosis in Ca2+ reperfusion injury of cultured astrocytes: roles of reactive oxygen species and NF-κB  activation Eur. J. Neurosci., 11 (1999), pp. 4204-4212 Kannan, K, Jain, SK. Oxidative stress and apoptosis. Pathophysiology. 2000. 7:153-163. Klein, Jeffrey A., and Susan L. Ackerman. "Oxidative stress, cell cycle, and neurodegeneration." The Journal of clinical investigation 111.6 (2003): 785-793. L.C. Hool, B. Corry Redox control of calcium channels: from mechanisms to therapeutic opportunities Antioxid. Redox Signal, 9 (2007), pp. 409-435 Lu, Tien-Hui, et al. "Arsenic induces reactive oxygen species-caused neuronal cell apoptosis through JNK/ERK-mediated mitochondria-dependent and GRP 78/CHOP-regulated pathways." Toxicology letters 224.1 (2014): 130-140. O.I. Aruoma, B. Halliwell, B.M. Hoey, J. Butler The antioxidant action of N-acetylcysteine: itS reaction with hydrogen peroxide, hydroxyl radical, superoxide, and hypochlorous acid Free Radic. Biol. Med., 6 (1989), pp. 593-597 Okouchi, Masahiro, et al. "Neuronal apoptosis in neurodegeneration." Antioxidants & redox signaling 9.8 (2007): 1059-1096. P.S. Brookes, Y. Yoon, J.L. Robotham, M.W. Anders, S.-S. Shen Calcium ATP and ROS: a mitochondrial love-hate triangle Am. J. Physiol. Cell Physiol., 287 (2004), pp.  817-833 Pias EK and Aw TY. Apoptosis in mitotic competent undifferentiated cells is induced by cellular redox imbalance independent of reactive oxygen species production. FASEB J 16:781–790, 2002 Pias EK and Aw TY. Early redox imbalance mediates hydroperoxide-induced apoptosis in mitotic competent undifferentiated PC-12 cells. Cell Death Differ 9: 1007–1016, 2002. Pias EK, Ekshyyan OY, Rhoads CA, Fuseler J, Harrison L, and Aw TY. Differential effects of superoxide dismutase isoform expression on hydroperoxide-induced apoptosis in PC-12 cells. J Biol Chem 278: 13294–13301, 2003. Pias EK, Ekshyyan OY, Rhoads CA, Fuseler J, Harrison L, and Aw TY. Differential effects of superoxide dismutase isoform expression on hydroperoxide-induced apoptosis in PC-12 cells. J Biol Chem 278: 13294–13301, 2003 Rocha, R. A., et al. "Arsenic and fluoride induce neural progenitor cell apoptosis." Toxicology letters 203.3 (2011): 237-244. Schulze–Osthoff K, Bakker AC, Vanhaesebroeck B, Beyaert R, Jacob WA, and Fiers W. Cytotoxic activity of tumor necrosis factor is mediated by early damage of mitochondrial function. J Biol Chem 267: 5317–5323, 1992. Takuma, Kazuhiro, Akemichi Baba, and Toshio Matsuda. "Astrocyte apoptosis: implications for neuroprotection." Progress in neurobiology 72.2 (2004): 111-127. </div> </div> AOPWiki 2023-07-18T14:52:35

2024-04-11T15:22:32

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AOPWiki 2026-03-25T08:52:42

2026-03-25T08:52:42

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AOPWiki 2026-03-25T08:52:55

2026-03-25T08:52:55

Co-exposure to microplastics and cadmium leading to progression from NAFLD to liver tumorigenesis

MPs & Cd induced inflammation-to-cancer transition in liver

Evgeniia Kazymova

李宇涵，牟为

BY-SA

2.8

This Adverse Outcome Pathway (AOP) describes the pathological transformation of the liver from non-alcoholic fatty liver disease (NAFLD) to cirrhosis and ultimately to hepatocellular carcinoma under the combined exposure of microplastics and cadmium. The Molecular Initiating Events (MIEs) are characterized by COL3A1 signaling pathway, ROS generation, and cytokine aggregation. These triggers lead to a series of Key Events (KEs), including alterations in ECM organization, increased cell proliferation, the occurrence of three distinct types of cell death, and chronic inflammation. This biological cascade eventually results in two primary Adverse Outcomes (AOs): liver cancer and hepatic fibrosis. By delineating these relationships, this AOP provides a novel scientific perspective on the hepatotoxicity induced by the interaction between microplastics and heavy metals. Microplastics (MPs), fragments and particles ≤5 mm in diameter, persistently accumulate in the environment and have been detected in various human tissues and organs, including infant placental tissues. Once ingested via food or water, MPs can deposit in the liver, leading to significant tissue injury. Polystyrene microplastics (PS-MPs), widely used in disposable food packaging, are frequently employed as models to study these environmental effects. Beyond their inherent toxicity, PS-MPs can enter the human body and serve as carriers for other environmental pollutants. Among these co-exposed contaminants, heavy metals such as cadmium (Cd) are of particular concern due to their high carcinogenicity and shared exposure pathways with MPs through aquatic products, agricultural goods, and water resources. Both MPs and Cd are ubiquitous pollutants that accumulate in the liver through food chain transfer and biomagnification, with absorbed dietary Cd exhibiting an exceptionally long biological half-life. As a primary target organ for both stressors, the liver undergoes amplified toxicological outcomes during co-exposure. Individual exposure to either Cd or MPs is known to induce oxidative stress, provoke inflammatory cascades, initiate apoptotic pathways, and disrupt hepatic metabolic homeostasis. When combined, these pollutants may result in a synergistic effect that accelerates pathological progression. External stimuli and a sustained inflammatory microenvironment are key drivers in the development of liver cancer. This tumorigenic process is highly heterogeneous and involves a continuum of metabolic disorders, where Non-Alcoholic Fatty Liver Disease (NAFLD) serves as a significant precursor to liver fibrosis and eventual malignancy. Research indicates that long-term Cd exposure can drive the entire disease progression from NAFLD to fibrosis and liver cancer through the activation of endogenous reactive oxygen species (ROS). Furthermore, higher concentrations of plastic particles have been detected in cirrhotic liver tissues compared to healthy ones, and joint exposure to PS-MPs and Cd has been shown to promote fibrosis by regulating oxidative stress and cell death. Given that the transformation from inflammation to cancer involves complex molecular cascades and extended periods, this AOP is developed as a predictive tool to construct a hazard assessment framework for the synergistic hepatotoxicity of microplastics and heavy metals.

Initial data on chemicals, genes, and disease interactions were collected from the CTD and GeneCards databases, focusing on the progression from NAFLD to liver cirrhosis and liver cancer. These target genes were categorized into three developmental stages and analyzed using GO and KEGG pathways, while protein-protein interaction networks were constructed to establish the molecular foundation. Following this preliminary predictive modeling, in vivo and in vitro experiments were conducted to provide empirical evidence for the proposed biological transitions. Existing knowledge from the AOP-Wiki regarding cadmium and microplastics was further integrated to build a baseline network of pollutant-induced liver injury. By synthesizing enrichment analysis, interaction networks, and experimental results, the upstream and downstream relationships of key genes and pathways were identified and weighted. This approach, combining computational prediction and experimental verification, led to the final construction of the AOP mapping the progression from NAFLD through liver cirrhosis to liver cancer under combined exposure.

From the OECD - GUIDANCE DOCUMENT ON DEVELOPING AND ASSESSING ADVERSE OUTCOME PATHWAYS - Series on Testing and Assessment 18: "...an adverse effect that is of regulatory interest (e.g. repeated dose liver fibrosis)"

Any cancer endpoint is considered to be adverse from a regulatory perspective. Substances causing cancer are regulated such that the general population is not exposed to levels that exceed the carcinogenic dose. The standard assay for carcinogens is the two-year rodent bioassay, which is conducted by the National Toxicology Program in the U.S.A. (https://ntp.niehs.nih.gov/). The International Agency on Research on Cancer (IARC; https://www.iarc.fr/) categorizes substances based on available evidence pointing to their ability to cause cancer in humans and/or animals.

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By integrating bioinformatic analysis and findings from in vivo and in vitro experiments with established AOPs of pollutant-induced hepatic injury, a comprehensive AOP network is constructed to delineate the "inflammation-to-cancer" disease progression under the combined exposure to MPs and Cd. Molecular associations were derived from CTD and GeneCards to reflect environmental impacts on human health. Empirical validation was conducted in vivo using four-week-old male BALB/c mice, and in vitro using murine AML12 hepatocytes and human HepG2 liver cancer cells.

MIEs: COL3A1 signaling pathway; Release, cytokine (MIE: 87); and Increased, ROS (MIE: 1115) The essentiality of these MIEs is supported by the fact that increased reactive oxygen species and cytokine release govern the entire disease trajectory, acting as the indispensable molecular triggers for downstream pathological remodelling. KE1: Modulation, Extracellular Matrix Composition (KE ID: 1195) As a structural protein essential to the ECM, COL3A1 expression is a requirement for ECM remodeling. The modulation of ECM composition is an essential functional transition leading to the adverse outcome of liver fibrosis. KE2-4: Pyroptosis (KE ID: 1967); Necrosis (KE ID: 1263); and Apoptosis (KE ID: 1262) The occurrence of multiple programmed cell death pathways is critical for the "inflammation-to-cancer" transformation. These KEs are essential, as they serve as the bridge linking early oxidative stress and cytokine signaling to chronic tissue damage. KE5: Activation of Inflammation (KE ID: 2009) Inflammatory activation is a necessary driver of the robust immune response and subsequent tissue damage. This KE is mediated by various forms of cell death and cytokines that occur across all disease stages. KE6: Increase, Cell Proliferation (KE ID: 870) Cell proliferation is a fundamental requirement for tumorigenesis following chronic injury. It represents the necessary final step linking chronic inflammatory damage and ECM modulation to the development of liver cancer.

MIEs to Cell Death and Cytokine Release Research indicates that combined exposure to microplastics and Cd significantly increases ROS levels and disrupts mitochondrial homeostasis, directly triggering the release of pro-inflammatory cytokines and initiating programmed cell death pathways. MIEs to KE1 (ECM Modulation) PPI analysis reveals that COL3A1 signaling is a central node impacting both "inflammatory/NAFLD" and "liver cirrhosis" phases. In co-exposure models, COL3A1 is consistently enriched in ECM-related pathways, and the elevation of integrin ITGB5 further confirms the role of cell-ECM interactions. KE2-4 (Cell Death) to KE5 (Inflammation) Analysis shows that necrosis-associated genes (BIRC3, RIPK3) and pyroptosis markers (CASP8) are enriched during disease progression. Necrosis and pyroptosis lead to cellular rupture and the release of intracellular contents, which activate the strong inflammatory response observed in animal models. KE1 & KE5 to KE6 (Cell Proliferation) Bioinformatic evidence demonstrates that cell proliferation pathways are activated following ECM modulation and NF-κB-mediated inflammation. The ECM regulates cellular activities, while persistent inflammation stimulates the growth of initiated cells. Pathway to Adverse Outcomes The integrated relationships among target genes and pathways facilitate the transition from NAFLD to liver fibrosis (defined by excessive ECM deposition) and ultimately to liver cancer (induced by sustained cell proliferation and inflammation).

<div> <table class="table table-bordered table-fullwidth"> <thead> <tr> <th>Modulating Factor (MF)</th> <th>Influence or Outcome</th> <th>KER(s) involved</th> </tr> </thead> <tbody> <tr> <td> </td> <td> </td> <td> </td> </tr> </tbody> </table> </div>

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