114798-26-4PSIFNNKUMBGKDQ-UHFFFAOYSA-NPSIFNNKUMBGKDQ-UHFFFAOYSA-N
Losartan1H-Imidazole-5-methanol, 2-butyl-4-chloro-1-[[2'-(1H-tetrazol-5-yl)[1,1'-biphenyl]-4-yl]methyl]-
DTXSID7023227CHEBI:3815collagenCHEBI:26523reactive oxygen speciesFMA:84050CytokineFMA:241981ChemokineFMA:86578InterleukinPR:000003622angiotensin-converting enzyme 2GO:0032964collagen biosynthetic processGO:1903409reactive oxygen species biosynthetic processGO:0043122regulation of I-kappaB kinase/NF-kappaB signalingGO:0002534cytokine production involved in inflammatory responseGO:0090195chemokine secretionGO:0006956complement activationGO:0009299mRNA transcriptionGO:0004180carboxypeptidase activityGO:0034394protein localization to cell surface1increased2decreasedPM 2.52020-03-02T05:42:162020-03-02T05:42:16Streptozocin2020-04-26T05:50:052020-04-26T05:50:05Losartan2020-04-26T05:51:102020-04-26T05:51:10DX6002021-02-11T10:25:482021-02-11T10:25:48cationic polyamidoamine dendrimer (nanoparticle)2021-02-11T10:29:082021-02-11T10:29:08Reactive oxygen species2017-06-16T08:32:102017-08-15T10:43:27Sars-CoV-2<p>Virus from the coronaviridae family related to SARS-CoV, 229E, NL63, OC43, HKU1 and MERS.</p>
<p>Transmitted by aerosols</p>
2021-02-23T04:50:402022-09-09T05:09:36SARS-CoV2020-03-01T10:42:462020-03-01T10:42:46Influenza Virus2021-12-05T12:32:162021-12-05T12:32:16WCS_9606human10116Rattus norvegicus10090mouseWikiUser_28Vertebrates9606Homo sapiens10116ratsIncreased Angiotensin II Increased AngIICellular2020-03-17T06:15:012021-04-04T08:00:36Induced dysregulation of ACE2 ACE2 enzymatic inhibitionMolecular2020-03-10T00:54:462022-03-03T08:59:49Accumulation, CollagenAccumulation, CollagenTissue<p>Collagen is mostly found in fibrous tissues such as tendons, ligaments and skin. It is also abundant in corneas, cartilage, bones, blood vessels, the gut, intervertebral discs, and the dentin in teeth. In muscle tissue, it serves as a major component of the endomysium. Collagen is the main structural protein in the extracellular space in the various connective tissues, making up from 25% to 35% of the whole-body protein content. In normal tissues, collagen provides strength, integrity, and structure. When tissues are disrupted following injury, collagen is needed to repair the defect. If too much collagen is deposited, normal anatomical structure is lost, function is compromised, and fibrosis results.</p>
<p>The fibroblast is the most common collagen producing cell. Collagen-producing cells may also arise from the process of transition of differentiated epithelial cells into mesenchymal cells. This has been observed e.g. during renal fibrosis (transformation of tubular epithelial cells into fibroblasts) and in liver injury (transdifferentiation of hepatocytes and cholangiocytes into fibroblasts) (Henderson and Iredale, 2007)<sup>.</sup></p>
<p>There are close to 20 different types of collagen found with the predominant form being type I collagen. This fibrillar form of collagen represents over 90 percent of our total collagen and is composed of three very long protein chains which are wrapped around each other to form a triple helical structure called a collagen monomer. Collagen is produced initially as a larger precursor molecule called procollagen. As the procollagen is secreted from the cell, procollagen proteinases remove the extension peptides from the ends of the molecule. The processed molecule is referred to as collagen and is involved in fiber formation. In the extracellular spaces the triple helical collagen molecules line up and begin to form fibrils and then fibers. Formation of stable crosslinks within and between the molecules is promoted by the enzyme lysyl oxidase and gives the collagen fibers tremendous strength (Diegelmann,2001)<sup>.</sup> The overall amount of collagen deposited by fibroblasts is a regulated balance between collagen synthesis and collagen catabolism. Disturbance of this balance leads to changes in the amount and composition of collagen. Changes in the composition of the extracellular matrix initiate positive feedback pathways that increase collagen production.</p>
<p>Normally, collagen in connective tissues has a slow turn over; degradating enzymes are collagenases, belonging to the family of matrix metalloproteinases. Other cells that can synthesize and release collagenase are macrophages, neutrophils, osteoclasts, and tumor cells (Di Lullo et al., 2002; Kivirikko and Risteli, 1976; Miller and Gay, 1987; Prockop and Kivirikko, 1995).</p>
<p> </p>
<p> </p>
<p>Determination of the amount of collagen produced in vitro can be done in a variety of ways ranging from simple colorimetric assays to elaborate chromatographic procedures using radioactive and non-radioactive material. What most of these procedures have in common is the need to destroy the cell layer to obtain solubilized collagen from the pericellular matrix. Rishikof et al. describe several methods to assess the in vitro production of type I collagen: Western immunoblotting of intact alpha1(I) collagen using antibodies directed to alpha1(I) collagen amino and carboxyl propeptides, the measurement of alpha1(I) collagen mRNA levels using real-time polymerase chain reaction, and methods to determine the transcriptional regulation of alpha1(I) collagen using a nuclear run-on assay (Rishikof et al., 2005). </p>
<p><span style="color:red"><span style="font-family:"Arial",sans-serif">Histological staining with stains such as Masson Trichrome, Picro-sirius red are used to identify the tissue/cellular distribution of collagen, which can be quantified using morphometric analysis both in vivo and in vitro. The assays are routinely used and are quantitative.</span></span></p>
<p><em><strong><span style="color:red"><span style="font-family:"Arial",sans-serif">Sircol Collagen Assay for collagen quantification:</span></span></strong></em></p>
<p><span style="color:red"><span style="font-family:"Arial",sans-serif">The Serius dye has been used for many decades to detect collagen in histology samples. The Serius Red F3BA selectively binds to collagen and the signal can be read at 540 nm (Chen and Raghunath, 2009; Nikota et al., 2017).</span></span></p>
<p><em><strong><span style="color:red"><span style="font-family:"Arial",sans-serif">Hydroxyproline assay:</span></span></strong></em></p>
<p><span style="color:red"><span style="font-family:"Arial",sans-serif">Hydroxyproline is a non-proteinogenic amino acid formed by the prolyl-4-hydroxylase. Hydroxyproline is only found in collagen and thus, it serves as a direct measure of the amount of collagen present in cells or tissues. Colorimetric methods are readily available and have been extensively used to quantify collagen using this assay (Chen and Raghunath, 2009; Nikota et al., 2017).</span></span></p>
<p><strong><em><span style="color:red"><span style="font-family:"Arial",sans-serif">Ex vivo precision cut tissue slices</span></span></em></strong></p>
<p><span style="color:red"><span style="font-family:"Arial",sans-serif">Precision cut tissue slices mimic the whole organ response and allow histological assessment, an endpoint of interest in regulatory decision making. While this technique uses animals, the number of animals required to conduct a dose-response study can be reduced to 1/4<sup>th</sup> of what will be used in whole animal exposure studies (Rahman et al., 2020). </span></span></p>
<p> </p>
<pre>
</pre>
<p>Humans: Bataller and Brenner, 2005; Decaris et al., 2015. </p>
<p>Mice: Dalton et al., 2009; Leung et al., 2008; Nan et al., 2013.</p>
<p>Rats: Hamdy and El-Demerdash, 2012; Li, Li et al., 2012; Luckey and Petersen, 2001; Natajaran et al., 2006.</p>
<p> </p>
UBERON:0002384connective tissueNot SpecifiedUnspecificNot SpecifiedAll life stagesHighHighHigh<ol>
<li>Bataller R, Brenner DA. Liver fibrosis. J Clin Invest. 2005 Feb;115(2):209-18. doi: 10.1172/JCI24282. </li>
<li>Chen CZ, Raghunath M. Focus on collagen: in vitro systems to study fibrogenesis and antifibrosis state of the art. Fibrogenesis Tissue Repair. 2009 Dec 15;2:7. doi: 10.1186/1755-1536-2-7. </li>
<li>Dalton SR, Lee SM, King RN, Nanji AA, Kharbanda KK, Casey CA, McVicker BL. Carbon tetrachloride-induced liver damage in asialoglycoprotein receptor-deficient mice. Biochem Pharmacol. 2009 Apr 1;77(7):1283-90. doi: 10.1016/j.bcp.2008.12.023. </li>
<li>Decaris ML, Emson CL, Li K, Gatmaitan M, Luo F, Cattin J, Nakamura C, Holmes WE, Angel TE, Peters MG, Turner SM, Hellerstein MK. Turnover rates of hepatic collagen and circulating collagen-associated proteins in humans with chronic liver disease. PLoS One. 2015 Apr 24;10(4):e0123311. doi: 10.1371/journal.pone.0123311.</li>
<li>Di Lullo GA, Sweeney SM, Korkko J, Ala-Kokko L, San Antonio JD. Mapping the ligand-binding sites and disease-associated mutations on the most abundant protein in the human, type I collagen. J Biol Chem. 2002 Feb 8;277(6):4223-31. doi: 10.1074/jbc.M110709200.</li>
<li>
<p><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">Diegelmann R. Collagen Metabolism. Wounds. 2001;13:177-82. Available at www.medscape.com/viewarticle/423231 (accessed on 20 January 2016).</span></span></p>
</li>
<li>Hamdy N, El-Demerdash E. New therapeutic aspect for carvedilol: antifibrotic effects of carvedilol in chronic carbon tetrachloride-induced liver damage. Toxicol Appl Pharmacol. 2012 Jun 15;261(3):292-9. doi: 10.1016/j.taap.2012.04.012. </li>
<li>Henderson NC, Iredale JP. Liver fibrosis: cellular mechanisms of progression and resolution. Clin Sci (Lond). 2007 Mar;112(5):265-80. doi: 10.1042/CS20060242.</li>
<li>Kivirikko KI, Risteli L. Biosynthesis of collagen and its alterations in pathological states. Med Biol. 1976 Jun;54(3):159-86.</li>
<li>Leung TM, Tipoe GL, Liong EC, Lau TY, Fung ML, Nanji AA. Endothelial nitric oxide synthase is a critical factor in experimental liver fibrosis. Int J Exp Pathol. 2008 Aug;89(4):241-50. doi: 10.1111/j.1365-2613.2008.00590.x. </li>
<li>Li L, Hu Z, Li W, Hu M, Ran J, Chen P, Sun Q. Establishment of a standardized liver fibrosis model with different pathological stages in rats. Gastroenterol Res Pract. 2012;2012:560345. doi: 10.1155/2012/560345. </li>
<li>Luckey SW, Petersen DR. Activation of Kupffer cells during the course of carbon tetrachloride-induced liver injury and fibrosis in rats. Exp Mol Pathol. 2001 Dec;71(3):226-40. doi: 10.1006/exmp.2001.2399.</li>
<li>Miller EJ, Gay S. The collagens: an overview and update. Methods Enzymol. 1987;144:3-41. doi: 10.1016/0076-6879(87)44170-0. </li>
<li>Nan YM, Kong LB, Ren WG, Wang RQ, Du JH, Li WC, Zhao SX, Zhang YG, Wu WJ, Di HL, Li Y, Yu J. Activation of peroxisome proliferator activated receptor alpha ameliorates ethanol mediated liver fibrosis in mice. Lipids Health Dis. 2013 Feb 6;12:11. doi: 10.1186/1476-511X-12-11.</li>
<li>Natarajan SK, Thomas S, Ramamoorthy P, Basivireddy J, Pulimood AB, Ramachandran A, Balasubramanian KA. Oxidative stress in the development of liver cirrhosis: a comparison of two different experimental models. J Gastroenterol Hepatol. 2006 Jun;21(6):947-57. doi: 10.1111/j.1440-1746.2006.04231.x.</li>
<li>Nikota J, Banville A, Goodwin LR, Wu D, Williams A, Yauk CL, Wallin H, Vogel U, Halappanavar S. Stat-6 signaling pathway and not Interleukin-1 mediates multi-walled carbon nanotube-induced lung fibrosis in mice: insights from an adverse outcome pathway framework. Part Fibre Toxicol. 2017 Sep 13;14(1):37. doi: 10.1186/s12989-017-0218-0. </li>
<li>Prockop DJ, Kivirikko KI. Collagens: molecular biology, diseases, and potentials for therapy. Annu Rev Biochem. 1995;64:403-34. doi: 10.1146/annurev.bi.64.070195.002155. </li>
<li>Rahman L, Williams A, Gelda K, Nikota J, Wu D, Vogel U, Halappanavar S. 21st Century Tools for Nanotoxicology: Transcriptomic Biomarker Panel and Precision-Cut Lung Slice Organ Mimic System for the Assessment of Nanomaterial-Induced Lung Fibrosis. Small. 2020 Sep;16(36):e2000272. doi: 10.1002/smll.202000272.</li>
<li>Rishikof DC, Kuang PP, Subramanian M, Goldstein RH. Methods for measuring type I collagen synthesis in vitro. Methods Mol Med. 2005;117:129-40. doi: 10.1385/1-59259-940-0:129. </li>
</ol>
2016-11-29T18:41:222023-04-25T11:56:49Lung fibrosisLung fibrosisOrgan<p>This consecutive KE resulting in the acquisition of the accumulation of excess fibrous connective tissue, the adverse outcome on pulmonary fibrosis. Scar formation, the accumulation of excess fibrous connective tissue (the process called fibrosis), leads to thickening of the walls, and causes reduced oxygen supply in the blood. As a consequence patients suffer from perpetual shortness of breath.</p>
2017-02-15T02:55:562017-12-26T02:10:27Binding of agonist, Angiotensin II receptor type 1 receptor (AT1R)Binding of agonist, Angiotensin II receptor type 1 receptor (AT1R)Molecular2021-03-30T12:38:502021-03-30T12:38:50Increased, Reactive oxygen speciesIncreased, Reactive oxygen speciesCellular<p>Biological State: increased reactive oxygen species (ROS)</p>
<p>Biological compartment: an entire cell -- may be cytosolic, may also enter organelles.</p>
<p>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). <br />
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). </p>
<p>Photocolorimetric assays (Sharma et al. 2017; Griendling et al. 2016) or through commercial kits purchased from specialized companies.</p>
<p>ROS is a normal constituent found in all organisms.</p>
HighUnspecificHighAll life stagesHigh<p>Bedard, Karen, and Karl-Heinz Krause. 2007. “The NOX Family of ROS-Generating NADPH Oxidases: Physiology and Pathophysiology.” Physiological Reviews 87 (1): 245–313.</p>
<p>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.</p>
<p>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.</p>
<p>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.</p>
<p>Parrish, A. R. 2010. “2.27 - Hypoxia/Ischemia Signaling.” In Comprehensive Toxicology (Second Edition), edited by Charlene A. McQueen, 529–42. Oxford: Elsevier.</p>
<p>Bisht, Shilpa, Muneeb Faiq, Madhuri Tolahunase, and Rima Dada. 2017. “Oxidative Stress and Male Infertility.” Nature Reviews. Urology 14 (8): 470–85.</p>
<p>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.</p>
<p>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.</p>
<p>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.</p>
2016-11-29T18:41:292023-04-10T14:01:30Increase activation, Nuclear factor kappa B (NF-kB)Increase activation, Nuclear factor kappa B (NF-kB)Cellular<p>The NF-kB pathway consists of a series of events where the transcription factors of the NF-kB family play a key role. The proinflammatory cytokine (IL-1beta) can be activated by NF-kB , including Reactive Oxygen Species produced by NADPH oxidase (NOX). Upon pathway activation, the IKK complex will be phosphorylated, which in turn phosphorylates IkBa. There, this transcription factor can express pro-inflammatory and pro-fibrotic genes. This can be achieved by ROS, IKK enhancer or nuclear translocation enhancer. </p>
<p>NF-kB transcriptional activity: Beta lactamase reporter gene assay (Miller et al. 2010). NF-kB transcription: Lentiviral NF-kB GFP reporter with flow cytometry (Moujalled et al. 2012)</p>
<p>NF-κB translocation: RelA-GFP reporter assay (Frederiksson 2012) (Huppelschoten 2017)</p>
<p>IκBa phosphorylation: Western blotting (Miller et al. 2010)</p>
<p>NF-κB p65 (Total/Phospho) ELISA</p>
<p>ELISA for IL-6, IL-8, and Cox</p>
<p>The ROS directly influences NF-κB signalling, resulting in differential production of cytokines and chemokines (McKay and Cidlowski, 1999; Pernis, 2007). NF-κB regulates pro-inflammatory responses that are transcriptionally mediated by NF‑κB.</p>
UBERON:0000479tissueCL:0000066epithelial cellNot SpecifiedMixedModerateNot Otherwise SpecifiedHigh2016-11-29T18:41:302021-03-30T13:17:17Increased, secretion of proinflammatory mediatorsIncreased proinflammatory mediatorsCellular<p><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">Pro-inflammatory mediators are the chemical and biological molecules that initiate and regulate inflammatory reactions. Pro-inflammatory mediators are secreted following exposure to an inflammogen in a gender/sex or developmental stage independent manner. They are secreted during inflammation in all species. Different types of pro-inflammatory mediators are secreted during innate or adaptive immune responses across various species (Mestas and Hughes, 2004). Cell-derived pro-inflammatory mediators include cytokines, chemokines, and growth factors. Blood derived pro-inflammatory mediators include vasoactive amines, complement activation products and others. These modulators can be grouped based on the cell type that secrete them, their cellular localisation and also based on the type of immune response they trigger. For example, members of the interleukin (IL) family including <a href="https://bioregistry.io/genecards:IL2">IL-2</a>, <a href="https://bioregistry.io/genecards:IL4">IL-4</a>, <a href="https://bioregistry.io/genecards:IL7">IL-7</a>, <a href="https://bioregistry.io/genecards:IL9">IL-9</a>, <a href="https://bioregistry.io/genecards:IL15">IL-15</a>, <a href="https://bioregistry.io/genecards:IL21">IL-21</a>, <a href="https://bioregistry.io/genecards:IL3">IL-3</a>, <a href="https://bioregistry.io/genecards:IL5">IL-5</a> and Granulocyte-macrophage colony stimulating factor (<a href="https://bioregistry.io/genecards:CSF2">GM-CSF</a>) are involved in the adaptive immune responses. The pro-inflammatory cytokines include IL-1 family (<a href="https://bioregistry.io/genecards:IL1a">IL-1</a></span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">α</span></span><span style="color:blue"><u><span style="font-size:11.0pt"><span style="font-family:"Calibri",sans-serif"> </span></span></u></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">, <a href="https://bioregistry.io/genecards:IL1b">IL-1</a></span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">β</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">, <a href="https://bioregistry.io/genecards:IL1ra">IL-1r</a></span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">α</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">, <a href="https://bioregistry.io/genecards:IL18">IL-18</a>, <a href="https://bioregistry.io/genecards:IL36a">IL-36</a></span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">α</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">, <a href="https://bioregistry.io/genecards:IL36b">IL-36</a></span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">β</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">, <a href="https://bioregistry.io/genecards:IL36g">IL-36</a></span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">γ</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">, <a href="https://bioregistry.io/genecards:IL36Ra">IL-36R</a></span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">α</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">, <a href="https://bioregistry.io/genecards:IL37">IL-37</a>), <a href="https://bioregistry.io/genecards:IL6">IL-6 </a>family, Tumor necrosis factor (<a href="https://bioregistry.io/genecards:TNF">TNF</a>) family, <a href="https://bioregistry.io/genecards:IL17">IL-17</a>, and Interferon gamma (<a href="https://bioregistry.io/genecards:IFNg">IFN</a>-</span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">γ</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">) (Turner et al., 2014). While <a href="https://bioregistry.io/genecards:IL4">IL-4</a> and <a href="https://bioregistry.io/genecards:IL5">IL-5</a> are considered T helper (Th) cell type 2 response, <a href="https://bioregistry.io/genecards:IFNg">IFN</a>-</span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">γ</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif"> is suggested to be Th1 type response.</span></span></p>
<p><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">Different types of pro-inflammatory mediators are secreted during innate or adaptive immune responses across various species (Mestas and Hughes, 2004). However, <a href="https://bioregistry.io/genecards:IL1">IL-1</a> family cytokines, <a href="https://bioregistry.io/genecards:IL4">IL-4</a>, <a href="https://bioregistry.io/genecards:IL5">IL-5</a>, <a href="https://bioregistry.io/genecards:IL6">IL-6</a>, <a href="https://bioregistry.io/genecards:TNFa">TNF</a>-</span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">α</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">, IFN-</span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">γ</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif"> are the commonly measured mediators in experimental animals and in humans. Similar gene expression patterns involving inflammation and matrix remodelling are observed in human patients of pulmonary fibrosis and mouse lungs exposed to bleomycin (Kaminski, 2002). </span></span></p>
<p><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif"><strong><em><span style="color:red">Literature evidence for its perturbation:</span></em></strong></span></span></p>
<p><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif"><span style="color:red">Several studies show increased proinflammatory mediators in rodent lungs and bronchoalveolar lavage fluid, and in cell culture supernatants following exposure to a variety of carbon nanotube (CNT) types and other materials</span>. Poland et al., 2008 showed that long and thin CNTs (>5 µm) can elicit asbestos-like pathogenicity through the continual release of pro-inflammatory cytokines and reactive oxygen species. Exposure to crystalline silica induces release of inflammatory cytokines (TNF-</span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">α</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">, IL-1, IL-6), transcription factors (Nuclear factor kappa B [NF-</span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">κ</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">B], Activator protein-1 [AP-1]) and kinase signalling pathways in mice that contain NF-</span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">κ</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">B luciferase reporter (Hubbard et al., 2002). Boyles et al., 2015 found that lung responses to long multi-walled carbon nanotubes (MWCNTs) included high expression levels of pro-inflammatory mediators Monocyte Chemoattractant Protein 1 (MCP-1), Transforming growth factor beta 1 (TGF-β1), and TNF-α (Boyles et al., 2015). Bleomycin administration in rodents induces lung inflammation and increased expression of pro-inflammatory mediators (Park et al., 2019). Inflammation induced by bleomycin, paraquat and CNTs is characterised by the altered expression of pro-inflammatory mediators. A large number of nanomaterials induce expression of cytokines and chemokines in lungs of rodents exposed via inhalation (Halappanavar et al., 2011; Husain et al., 2015a). Similarities are observed in gene programs involving pro-inflammatory event is observed in both humans and experimental mice (Zuo et al., 2002).</span></span></p>
<p><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">The selection of pro-inflammatory mediators for investigation varies based on the expertise of the lab, cell types studied and the availability of the specific antibodies.</span></span></p>
<p><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif"><u>Real-time reverse transcription-polymerase chain reaction (qRT-PCR)</u> – will measure the abundance of cytokine mRNA in a given sample. The method involves three steps: conversion of RNA into cDNA by reverse transcription method, amplification of cDNA using the PCR, and the real-time detection and quantification of amplified products (amplicons) (Nolan T et al., 2006). Amplicons are detected using fluorescence, increase in which is directly proportional to the amplified PCR product. The number of cycles required per sample to reach a certain threshold of fluorescence (set by the user – usually set in the linear phase of the amplification, and the observed difference in samples to cross the set threshold reflects the initial amount available for amplification) is used to quantify the relative amount in the samples. The amplified products are detected by the DNA intercalating minor groove-binding fluorophore SYBR green, which produces a signal when incorporated into double-stranded amplicons. Since the cDNA is single stranded, the dye does not bind enhancing the specificity of the results. There are other methods such as nested fluorescent probes for detection, but SYBR green is widely used. RT-PCR primers specific to several pro-inflammatory mediators in several species including mouse, rat and humans, are readily available commercially.</span></span></p>
<p><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif"><u>Enzyme-linked immunosorbent assays (ELISA)</u> – permit quantitative measurement of antigens in biological samples. The method is the same as described for the MIE. Both ELISA and qRT-PCR assays are used in vivo and are readily applicable to in vitro cell culture models, where cell culture supernatants or whole cell homogenates are used for ELISA or mRNA assays. Both assays are straight forward, quantitative and require relatively a small amount of input sample. </span></span></p>
<p><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">Apart from assaying single protein or gene at a time, cytokine bead arrays or cytokine PCR arrays can also be used to detect a whole panel of inflammatory mediators in a multiplex method (Husain et al., 2015b). This method is quantitative and especially advantageous when the sample amount available for testing is scarce. Lastly, immunohistochemistry can also be used to detect specific immune cell types producing the pro-inflammatory mediators and its downstream effectors in any given tissue (Costa et al., 2017). Immunohistochemistry results can be used as weight of evidence; however, the technique is not quantitative and depending on the specific antibodies used, the assay sensitivity may also become an issue (Amsen and De Visser, 2009).</span></span></p>
<p><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif"><span style="color:red"><u>Cell models</u> - of varying complexity have been used to assess the expression of pro-inflammatory mediators. Two dimensional submerged monocultures of the main fibrotic effector cells – lung epithelial cells, macrophages, and fibroblasts – have routinely been used <em>in vitro</em> due to the large literature base, and ease of use, but do not adequately mimic the <em>in vivo</em> condition (Sundarakrishnan <em>et al.,</em> 2018, Sharma <em>et al.,</em> 2016). Recently, the EpiAlveolar <em>in vitro</em> lung model (containing epithelial cells, endothelial cells, and fibroblasts) was used to predict the fibrotic potential of MWCNT, and researchers noted increases in the pro-inflammatory molecules TNF-</span></span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">α</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif"><span style="color:red">, IL-1</span></span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">β</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif"><span style="color:red">, and the pro-fibrotic TGF-</span></span></span><span style="font-size:11.0pt"><span style="font-family:"Arial",sans-serif">β</span></span><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif"><span style="color:red"> using ELISA (Barasova <em>et al.,</em> 2020). A similar, but less complicated co-culture model of immortalized human alveolar epithelial cells and idiopathic pulmonary fibrosis patient derived fibroblasts was used to assess pro-fibrotic signalling, and noted enhanced secretion of Platelet derived growth factor (PDGF) and Basic fibroblast growth factor (bFGF), as well as evidence for epithelial to mesenchymal transition of epithelial cells in this system (Prasad et al., 2014). Models such as these better capitulate the <em>in vivo</em> pulmonary alveolar capillary, but have lower reproducibility as compared to traditional submerged mono-culture experiments. </span></span></span></p>
<p><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif"><span style="color:red">Human, mouse, rat</span></span></span></p>
<p><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">Cytokines are the common pro-inflammatory mediators secreted following inflammogenic stimuli. Cytokines can be defined as diverse group of signaling protein molecules. They are secreted by different cell types in different tissues and in all mammalian species, irrespective of gender, age or sex. A lot of literature is available to support cross species, gender and developmental stage application for this KE. The challenge is the specificity; most cytokines exhibit redundant functions and many are pleotropic.</span></span></p>
CL:0000255eukaryotic cellHighMaleHighFemaleHighAdultsHighHighHigh<p><span style="color:#000000"><span style="font-family:Calibri">1. </span></span>Amsen D, de Visser KE, Town T. Approaches to determine expression of inflammatory cytokines. Methods Mol Biol. 2009;511:107-42. doi: 10.1007/978-1-59745-447-6_5. </p>
<p><span style="color:red"><span style="font-family:Calibri">2. </span></span>Barosova H, Maione AG, Septiadi D, Sharma M, Haeni L, Balog S, O'Connell O, Jackson GR, Brown D, Clippinger AJ, Hayden P, Petri-Fink A, Stone V, Rothen-Rutishauser B. Use of EpiAlveolar Lung Model to Predict Fibrotic Potential of Multiwalled Carbon Nanotubes. ACS Nano. 2020 Apr 28;14(4):3941-3956. doi: 10.1021/acsnano.9b06860. </p>
<p><span style="color:#000000"><span style="font-family:Calibri">3. </span></span>Boyles MS, Young L, Brown DM, MacCalman L, Cowie H, Moisala A, Smail F, Smith PJ, Proudfoot L, Windle AH, Stone V. Multi-walled carbon nanotube induced frustrated phagocytosis, cytotoxicity and pro-inflammatory conditions in macrophages are length dependent and greater than that of asbestos. Toxicol In Vitro. 2015 Oct;29(7):1513-28. doi: 10.1016/j.tiv.2015.06.012. </p>
<p><span style="color:#000000"><span style="font-family:Calibri">4. </span></span>Costa PM, Gosens I, Williams A, Farcal L, Pantano D, Brown DM, Stone V, Cassee FR, Halappanavar S, Fadeel B. Transcriptional profiling reveals gene expression changes associated with inflammation and cell proliferation following short-term inhalation exposure to copper oxide nanoparticles. J Appl Toxicol. 2018 Mar;38(3):385-397. doi: 10.1002/jat.3548.</p>
<p><span style="color:#000000"><span style="font-family:Calibri">5. </span></span>Halappanavar S, Jackson P, Williams A, Jensen KA, Hougaard KS, Vogel U, Yauk CL, Wallin H. Pulmonary response to surface-coated nanotitanium dioxide particles includes induction of acute phase response genes, inflammatory cascades, and changes in microRNAs: a toxicogenomic study. Environ Mol Mutagen. 2011 Jul;52(6):425-39. doi: 10.1002/em.20639. </p>
<p><span style="color:#000000"><span style="font-family:Calibri">6. </span></span>Hubbard AK, Timblin CR, Shukla A, Rincón M, Mossman BT. Activation of NF-kappaB-dependent gene expression by silica in lungs of luciferase reporter mice. Am J Physiol Lung Cell Mol Physiol. 2002 May;282(5):L968-75. doi: 10.1152/ajplung.00327.2001.</p>
<p><span style="color:#000000"><span style="font-family:Calibri">7. </span></span>Husain M, Kyjovska ZO, Bourdon-Lacombe J, Saber AT, Jensen KA, Jacobsen NR, Williams A, Wallin H, Halappanavar S, Vogel U, Yauk CL. Carbon black nanoparticles induce biphasic gene expression changes associated with inflammatory responses in the lungs of C57BL/6 mice following a single intratracheal instillation. Toxicol Appl Pharmacol. 2015a Dec 15;289(3):573-88. doi: 10.1016/j.taap.2015.11.003.</p>
<p><span style="color:#000000"><span style="font-family:Calibri">8. </span></span>Husain M, Wu D, Saber AT, Decan N, Jacobsen NR, Williams A, Yauk CL, Wallin H, Vogel U, Halappanavar S. Intratracheally instilled titanium dioxide nanoparticles translocate to heart and liver and activate complement cascade in the heart of C57BL/6 mice. Nanotoxicology. 2015b;9(8):1013-22. doi: 10.3109/17435390.2014.996192.</p>
<p><span style="color:#000000"><span style="font-family:Calibri">9. </span></span>Kaminski N. Microarray analysis of idiopathic pulmonary fibrosis. Am J Respir Cell Mol Biol. 2003 Sep;29(3 Suppl):S32-6.</p>
<p><span style="color:#000000"><span style="font-family:Calibri">10. </span></span>Mestas J, Hughes CC. Of mice and not men: differences between mouse and human immunology. J Immunol. 2004 Mar 1;172(5):2731-8. doi: 10.4049/jimmunol.172.5.2731.</p>
<p><span style="color:#000000"><span style="font-family:Calibri">11. </span></span>Nolan T, Hands RE, Bustin SA. Quantification of mRNA using real-time RT-PCR. Nat Protoc. 2006;1(3):1559-82. doi: 10.1038/nprot.2006.236.</p>
<p><span style="color:#000000"><span style="font-family:Calibri">12. </span></span>Park SJ, Im DS. Deficiency of Sphingosine-1-Phosphate Receptor 2 (S1P<sub>2</sub>) Attenuates Bleomycin-Induced Pulmonary Fibrosis. Biomol Ther (Seoul). 2019 May 1;27(3):318-326. doi: 10.4062/biomolther.2018.131.</p>
<p><span style="color:#000000"><span style="font-family:Calibri">13. </span></span>Poland CA, Duffin R, Kinloch I, Maynard A, Wallace WA, Seaton A, Stone V, Brown S, Macnee W, Donaldson K. Carbon nanotubes introduced into the abdominal cavity of mice show asbestos-like pathogenicity in a pilot study. Nat Nanotechnol. 2008 Jul;3(7):423-8. doi: 10.1038/nnano.2008.111.</p>
<p><span style="color:red"><span style="font-family:Calibri">14. </span></span>Prasad S, Hogaboam CM, Jarai G. Deficient repair response of IPF fibroblasts in a co-culture model of epithelial injury and repair. Fibrogenesis Tissue Repair. 2014 Apr 29;7:7. doi: 10.1186/1755-1536-7-7. </p>
<p><span style="color:red"><span style="font-family:Calibri">15. </span></span>Sharma M, Nikota J, Halappanavar S, Castranova V, Rothen-Rutishauser B, Clippinger AJ. Predicting pulmonary fibrosis in humans after exposure to multi-walled carbon nanotubes (MWCNTs). Arch Toxicol. 2016 Jul;90(7):1605-22. doi: 10.1007/s00204-016-1742-7. </p>
<p><span style="color:red"><span style="font-family:Calibri">16. </span></span>Sundarakrishnan A, Chen Y, Black LD, Aldridge BB, Kaplan DL. Engineered cell and tissue models of pulmonary fibrosis. Adv Drug Deliv Rev. 2018 Apr;129:78-94. doi: 10.1016/j.addr.2017.12.013.</p>
<p><span style="color:#000000"><span style="font-family:Calibri">17. </span></span>Turner MD, Nedjai B, Hurst T, Pennington DJ. Cytokines and chemokines: At the crossroads of cell signalling and inflammatory disease. Biochim Biophys Acta. 2014 Nov;1843(11):2563-2582. doi: 10.1016/j.bbamcr.2014.05.014. </p>
<p><span style="color:#000000"><span style="font-family:Calibri">18. </span></span>Zuo F, Kaminski N, Eugui E, Allard J, Yakhini Z, Ben-Dor A, Lollini L, Morris D, Kim Y, DeLustro B, Sheppard D, Pardo A, Selman M, Heller RA. Gene expression analysis reveals matrilysin as a key regulator of pulmonary fibrosis in mice and humans. Proc Natl Acad Sci U S A. 2002 Apr 30;99(9):6292-7. doi: 10.1073/pnas.092134099.</p>
2018-01-02T13:12:112023-04-21T09:51:32Dysregulation, ACE2 expression and activityACE2 dysregulationMolecular<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">The angiotensin-converting enzyme 2 (ACE2) is a membrane-anchored protein with wide tissue distribution </span><a href="https://www.proteinatlas.org/ENSG00000130234-ACE2" style="color:#0563c1; text-decoration:underline"><span style="background-color:white">https://www.proteinatlas.org/ENSG00000130234-ACE2</span></a><span style="background-color:white">. </span>ACE2 has multiple functions, and is highly regulated at the transcriptional, post-transcriptional and post-translational levels. Modulation of the expression levels or functional activity of the ACE2 receptor is described in this KE. </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"> ACE2 is bound to cell membranes, and in polarized cells it is exclusively targeted to the apical surface (Werner 2005; Ren 2006) [for more detailed description of the expression patterns of ACE2 see the applicability domain section]. </span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">ACE2 FUNCTIONS</span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">Enzymatic function of ACE2 in interlinked bioactive peptide systems </span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">ACE2 is mainly known and studied as a type I ectoenzyme i.e. a transmembrane protein with an extracellular amino-terminal domain harbouring a carboxypeptidase active site. ACE2 cleaves the carboxyterminal amino acid from a number of biologically active peptides (Figure 1 and 2), thus activating or deactivating them as agonists within the Renin Angiotensin System (RAS) (Santos et al., 2019) and within the</span> <span style="background-color:white">Kinin–kallikrein system (KKS) (Kakoki & Oliver, 2009) in mammals. </span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">The extracellular domain of ACE2 can itself be cleaved (shedding) in vitro and in vivo, releasing a soluble and catalytically active sACE2 (Guy et al., 2008 in human cardiac myofibroblasts; Peng Jia et al., 2009 in human lung epithelial cells and BALF; Werner et al., 2005 in canine</span> epithelial polarised kidney <span style="background-color:white">MDCKII cells stabilly expressing ACE2). Constitutive shedding of ACE2 from the cellular membrane is mediated by another membrane-bound metalloprotease from the adamalysin family, ADAM17 (Iwata et al., 2009) also known as TACE, TNFalpha Converting Enzyme (Zunke 2017). Other proteins may also be involved in ACE2 protolithic modulation (Lambert et al, 2008). </span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">The exact role of ACE2 shedding in modulating its function is not well understood, however, being catalytically active, the released sACE2 can, as the membrane-anchored full length ACE2, generate biologically active peptides which activate specific receptors in different cells/tissues/organs. Thus, the ACE2 function in the organism is mediated via its peptide products activating specific receptors on the same, (autocrine), nearby (paracrine) and potentially distant cells. </span><a name="_heading=h.gjdgxs"></a></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"> </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">ACE2 is a homologue of angiotensin-converting enzyme (ACE), with whom it shares significant sequence similarity (Tipnis, 2000; Donoghue 2000), yet exhibits very distinct enzymatic activity. ACE2, as ACE, is a zink-metallopeptid</span><span style="background-color:white">a</span><span style="background-color:white">se, however ACE2 is strictly a carboxypeptidase while ACE is an dipeptidase. Furthermore, the main substrate of ACE2 is the octopeptide Angiotensin II (Ang II), the enzymatic product of its homologue ACE. By cleaving a single amino acid from the C-terminus of Ang II, ACE2 generates a functionally different bioactive peptide Angiotensin 1-7 (Ang1-7) (Figure 1). ACE2 is key to the regulation of local and systemic Ang II levels. </span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">Ultimately, the function of ACE2 at tissue level is mediated via the interaction of its main active product Ang1-7 with the Angiotensin II receptor 2 (AT2R), balanced by the activity of its homologue ACE and other peptidases in the RAS.</span></span></span></p>
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<p> </p>
<p> </p>
<p> </p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">Figure1: Enzymatic activity of ACE2 compared to its homologue ACE and another protease relevant to the RAS (from Rice et al., 2004)</span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">[to add]</span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Figure 2: Simplified representation of the biological function of the enzymatic products of ACE2 activity in the KKS (adopted from Kakoki & Oliver, 2009). </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">[to add]</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Although most studies have focused on the role of ACE2 in angiotensin metabolism in the RAS, the enzyme has broad substrate specificity and it also hydrolyses a number of other biologically active peptides including des-Arg9-bradykinin (DABK), apelin-13, neurotensin(1–11), dynorphin A-1–13), β-casomorphin-(1–7), and ghrelin (Vickers 2002, Humming, 2007.</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">ACE2 cleavage of DABK to bradykinin 1-7 <span style="background-color:white">(Figure 2) has been demonstrated in chemico (</span>Donoghue 2000, Vickers 2002)<span style="background-color:white">, with human polarised primary lung cells in vitro and in mice broncho-alveolar lavage (BALF) </span>(Sodhi 2018<span style="background-color:white">). Deactivation of DBAK, a preferencial bradikynin receptor 1 (B1K) agonist (</span>Coulson et al., 2019), <span style="background-color:white">is an important regulatory function of ACE2 in </span>the <span style="background-color:white">KKS (Figure 2).</span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">1.2 ACE2 chaperone function for transporters of amino acid transfer (B0AT1)</span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Somewhat less known is the RAS independent function of ACE2 in the gut, where it regulates intestinal amino acid homeostasis, expression of antimicrobial peptides, and the gut microbiome (Camargo et al., 2020). ACE2 was identified as an important regulator of dietary amino acid homeostasis, innate immunity, gut microbial ecology, and transmissible susceptibility to colitis in mice (Hashimoto et al., 2012). The mechanism by which ACE2 regulates amino acid transport in the intestine involves interaction with the broad neutral (0) amino acid transporter 1 (B0AT1) (Slc6a19) which mediates the uptake of neutral dietary amino acids, such as tryptophan and glutamine, into intestinal cells in a sodium-dependent manner (Camargo et al, 2009). A crystal structure study revealed a complex dimer of ACE2/ B0AT1 heterodimers (Yan et al., 2020), previously suggested by immunoprecipitation of intestinal membrane proteins in mice (Fairweather et al., 2012). Immunofluorescence showed co-localization of B0AT1 with ACE2 at the luminal surface of human small intestine (Vuille-dit-Bille et al., 2015). ACE2 seems to be necessary not only for the amino acid transfer by B0AT1, but also for its membrane expression (Camargo et al., 2008; Hashimoto et al., 2012). </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"> <span style="background-color:white">REGULATION OF ACE2 </span> <span style="background-color:white">LEVELS and ACTIVITY</span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">ACE2 is regulated at the transcriptional, post-transcriptional and post-translational level, <span style="background-color:white">the final potentially differing in the different organisational contexts: cell membrane versus tissue (plasma and/or interstitial). In addition, all of these regulatory processes may be differentially modulated in different tissues.</span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:red">Age, sex and species specific differences</span> in aspects of the regulation, and also tissue specific regulation, have been reported (reviewed in Saponaro 2020). </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">Loss of function of ACE2 in vivo in ACE2 knockout (KO) mice has been associated with elevated levels of Ang II in heart, kidney and plasma as well as histological and functional perturbations in the lungs and in the cardiovascular (Crackower et al, Nature 2002) and renal (Oudit et al, 2010) systems, mostly in the presence of a particular stress factor, in some cases potentiated by aging (reviewed in Humming 2007). </span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Furthermore, Ace2 KO mice exhibited reduced serum levels of tryptophan, together with downregulated expression of small intestinal antimicrobial peptides and altered gut microbiota, which was re-established by tryptophan supplementation (Hashimoto et a., 2012). </span></span></p>
<p> </p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">At transcriptional level </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Overall, the transcriptional regulatory elements of the ace2 gene are not well characterised. </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Ace2, human but not mouse, was identified as an Interferon Stimulated Gene (ISG) in airway epithelial cells (Ziegler, 2020), indicating species specific regulation and its importance for human viral infections mediated via ACE2 (e.g. SARS-COV2). Influenza virus infection also induced ACE2 mRNA synthesis in human lung tissue (Ziegler, 2020).</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">In vitro in normal kidney tubular epithelial cell line (HK-2) ACE2 mRNA is down-regulated following Ang II treatment (Koka 2008). The exact transcriptional regulatory mechanism is not clear, but the observed ACE2 mRNA up-regulation in this system appears to be mediated by the activation of the ERK1/2 and p38 MAP kinase pathway and dependent on the activation of AT1R receptor by AngII, as demonstrated by specific AT1R, MAP kinase and ERK1/2 MAP kinase inhibitors (Koka et al., 2008). Regulation of ACE2 expression mediated by AT1R activation is an important endogenous regulatory mechanism for ACE2 activity within the RAS system (<span style="background-color:lightgrey">ref…..).</span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Vitamin D Receptor (VDR) may also emerge as an ACE2 transcriptional regulator/repressor (Saponaro 2020 and Glinsky 2020, unreviewed pre-print). VDR has already been implicated in the transcriptional repression of Renin, at least in vitro (Yuan 2007). </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">17b-estradiol (E2) has also been indicated in the transcriptional regulation of ace2 in a tissue specific manner (recently reviewed by Saponaro 2020). E2 down-regulated ace2 transcription particularly in kidney and differentiated airway epithelial cells. However, in human atrial tissue, E2 appeared to up-regulate ACE2 mRNA and protein. This change was associated with decreased levels of ACE homologue protein. The exact mechanism for this regulation remains to be elucidated as it may represent a significant <span style="background-color:red">modulating factor</span> in the differential <span style="background-color:red">sex</span> susceptibility to ACE2 dysregulation under varied stress conditions (e.g SARS-COV infection).</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Epigenetic transcriptional regulation of ace2 has also been indicated (recently reviewed by Saponaro 2020. Transcription of ace2 is repressed by histone methylation and stimulated by NAD+-dependent deacetylase SIRT1 during cellular energy stress. Interestingly, <span style="background-color:red">in children</span> ACE2 is normally hypermethylated and poorly expressed in the lung and in other organs (Saponaro 2020, ref therein).</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Gut microbiota have also been implicated in the transcriptional regulation of ACE2 expression in the gut (Yang et al., 2020) but also in the lung (Koester et al., 2021). Whether this is directly or indirectly occurring via microbial metabolites remains to be elucidated, but the study by Koester ar e al, 2020 observed variability in intestinal Ace2 expression in gnotobiotic mice colonized with different microbiota, partially attributable to differences in microbiome-encoded proteases and peptidases.</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">At post-transcriptional level</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Generally, modulation of ACE2 mRNA and protein levels appear to follow consistent pattern. However, it has been demonstrated that under certain conditions and in some tissues, mRNA and protein levels appear to follow a different pattern, suggesting important role of post-transcriptional or post-translational (see next section) regulation of ACE2 expression and function.</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">For example, hypertension in humans has been associated with different modulation of mRNA and protein levels in the heart tissue (Koka 2008). Specifically, heart tissue from patients with hypertension showed decreased levels of ACE2 mRNA while protein levels were comparable to normal tissue. In contrast, ACE mRNA and protein levels appeared consistently up-regulated in hart tissue of hypertensive patients (Koka 2008). In the same study, in the kidney tissue from patients with hypertensive nephropathy, both, ACE2 mRNA and protein levels, appeared consistently down-regulated compared to normal kidney tissue (Koka 2008). Significant suppression of ACE2 mRNA and protein expression was also observed in vitro in normal kidney tubular epithelial cell line (HK-2) treated with AngII (linked to hypertension in vivo) in a dose and time dependent manner Koka 2008). AngII treatment in vitro with myocardia- derived cells was not examined in this study and the discrepancy of mRNA and protein level modulation in the hypertensive human heart tissue biopsies was attributed by the authors to limitations of the detecting methods (Koka 2008). </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Clear discrepancy in the modulation of mRNA versus protein level has been observed in vivo in mice in myocardial tissue (Patel 2014). Namely, up-regulation of mRNA synthesis was associated with down-regulation of ACE2 protein levels following 1 or 2 week treatment by exogenous circulating AngII (Patel 2014). In this study, down-regulation of ACE2 protein levels was alleviated by AT1R blockage/inhibitors, while mRNA up-regulation was not dependent on AT1R signalling. This strongly suggests involvement of post-transcriptional mechanism step(s) mediated by AngII/AT1R fot the regulation of ACE2 protein/function, at least in myocardial tissue under certain stress conditions. </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Modulation of ACE2 protein and activity levels by AngII is clinically relevant phenomenon and AngII activity blockers (ACE inhibitors and AT1R blockers) are used to move the balance of the RAS from the ACE/AngII/AT1R axis towards the protective ACE2/Ang1-7/MasR axis. This is particularly relevant in the lung where ACE/ACE2 activity ratio is high (Roca-Ho, 2017-mice, <span style="background-color:yellow">human and other ref……?..).</span> </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">The up-regulation of ACE2 mRNA observed in mouse myocardial tissue by Patel et al., 2014 appears contradictory to the finding of ACE2 mRNA down-regulation observed in the heart of hypertensive patients observed in the study of Koka et al., 2008 (if the latter result is accepted despite potential method limitations). However, it should be noted that the base level of ACE2 and also the relative ACE2/ACE ratio in the case of chronic hypertensive patients, many of whom have been on AT1R inhibitor treatment (Koka 2008), and in healthy mice treated with AngII for relatively short time (Patel 2014), may be different leading to response to the stressor (hypertension and AngII) over time. Consistent with this, distinct ACE/ACE2 activity ratios have been demonstrated in different organs of normal, non-obese diabetic (NOD) and insulin treated NOD mice, which varied additionally over the time course after the onset of diabetes (Roca-Ho et al., 2014). </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Finally, species specific regulatory differences may be involved that would warrant further examination. But, overall, the studies discussed above illustrate the complex regulatory mechanisms of ACE2 mRNA, protein and activity levels in different tissues and under different stress conditions for the RAS system. </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Rapid and transient up-regulation of ACE2 mRNA followed by down-regulation of ACE2 protein levels has been reported in the lung as a result of LPS induced acute inflammation in mice (Sodhi 2018). In this case the increase of ACE2 mRNA appears to be a rapid and transient compensatory effect to ACE2 protein/activity down-regulation mediated by NFk- B signalling in response to acute inflammation. Inhibiting NF- B signaling by Bay11-7082 restored ACE2 activity, again demonstrating post transcriptional or translational regulation of ACE2 in the lungs. In addition, this study examined the effect of ACE2 dysregulation on the KKS and demonstrated that attenuation of ACE2 activity under conditions of LPS induced inflammation leads to impaired DABK inactivation and enhanced BKB1R signalling (Sodhi 2018).</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:lightgrey">The underlying mechanisms of post-transcriptional mRNA regulation remain to be elucidated further. There is evidence that small non-coding micro RNAs (</span><span style="background-color:lightgrey">miRNA or miRs) may be involved </span></span><span style="font-family:"Calibri","sans-serif""> <span style="background-color:yellow">(</span>Widiasta 2020; Lu 2020; Fang 2017, Lambert 2014 </span></span><span style="font-family:Calibri,"sans-serif"; font-size:11pt">).</span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">At post-translational level – enzymatic activity including shedding</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">Complexity of analysing the regulation of ACE2 function is emphasized even further when enzymatic activity is considered, including its spatial distribution between cell/tissue versus interstitium/plasma, mediated by shedding.</span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">The exact role of ACE2 shedding is not well understood, but proteolytic ectodomain shedding of membrane proteins is a fundamental post-translational regulatory mechanism of the activity/function of a wide variety of proteins, including growth factors, cytokines, receptors and cell adhesion proteins (Lichtenthaler et al., 2018). </span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">sACE2 activity is increased in patients with heart failure (HF) and correlates with disease severity </span><span style="background-color:white">(Epelman 2008).</span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="background-color:white">In mice in vivo, shedding of ACE2 by TACE was induced by sub-chronic (2 weeks) exogenous AngII treatment (mimicking HF), leading to decreased ACE2 protein level and increased ACE2 mRNA in myocardial tissue </span><span style="background-color:yellow">with concurrent elevated sACE2 activity</span><span style="background-color:white"> (Patel et al., </span><span style="background-color:white">2014). </span> </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif">ACE2 activity </span></span></strong></span></span></p>
<ul>
<li><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:black">using fluorescently labeled peptide <u>substrates</u> (Rice, 2004; Sodhi, 2008; Roca-Ho, 2017 1; Lu and Sun, 2020; Xiao 2017) </span></span></span></li>
<li><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:black">measuring catalytic <u>products</u> (direct) or markers of <u>activation of receptors for the products</u> (indirect) of ACE2 activity (e.g Ferrario 2005)</span></span></span></li>
</ul>
<p> </p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif">ACE2 levels</span></span></strong> </span></span></p>
<ul>
<li><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:black">mRNA by RT-PCR (Sodhi 2018; Roca-Ho, 2017) or scRNA seq (e.g. Qi. et al 2020)</span></span></span></li>
<li><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:black">protein in tissue extracts/preparations by immunoprecipitation or Western blotting (Koka 2008)</span></span></span></li>
<li><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:black">protein in live tissues or cultured cells by immunostaining (Humming 2007; Fraga-Silva et al., 2011; Ren 2006; Warner 2005)</span></span></span></li>
</ul>
<p><span style="font-size:11.0pt"><span style="font-family:"Calibri",sans-serif"><span style="color:black">high throughput and quantitative measurement of protein by quantitative proteomic analysis (Park 2020; Stegbauer 2020)</span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">ACE2 is expressed in a wide variety of tissues affecting their function. </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">ACE2 was initially identified in human lymphoma cDNA library (Tipnis, 2000), and from a human cDNA library of ventricular cells with heart failure (Donoghue 2000). Expression of ACE2 has later been also identified in the heart, kidney, and testis (Donoghue et al. (2000b). However, subsequent studies have shown a much broader distribution, including the upper airways, lungs, gut, and liver (reviewed recently by Saponaro, 2020). </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><em>Tissue and sub-cellular distribution of ACE2 (protein and mRNA)</em></strong></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><em>Protein expression patterns</em></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Immunostaining methods show that ACE2 is chiefly bound to cell membranes, predominantly in the smooth muscle cells and in the endothelium of the vasculature, while negligible levels can be detected in the circulation. In blood cells, it has been observed in platelets and macrophages, but not in B and T lymphocytes (Hamming et al., 2004; Fraga-Silva et al., 2011).</span></span></p>
<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">ACE2 shows differential sub-cellular distribution which can be significant for its basal/constitutive and modulated function. It is mainly detectable at the cell-surface with little intracellular localization, and the protein does not readily internalize (Warner et al., 2005). In polarized cells, ACE2 is exclusively targeted to the apical surface in vivo in kidney (Warner 2005) and in vitro in polarised cells derived from the colon, lung and kidney (Ren 2006). This is in contrast to its sequence homologue and functional “balancer” ACE, which distributes equally between apical and basolateral surfaces (Warner 2005). </span></span></p>
<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">In the small intestines, ACE2 is highly expressed on enterocytes and via its local RAS function participates in the regulation of the intestinal glucose transport. Intestinal ACE2 generates locally Ang 1-7 from luminal Ang II. Ang II was shown to inhibit SGLT1-dependent intestinal glucose uptake in a dose-dependent manner<em> in vitro </em>and<em> in vivo </em>in rats<em> </em>(Wong et al, 2007; 2009) and in human biopsies via AT1R activation (Casselbrant et al., 2015). </span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><em>mRNA expression patterns</em></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">More recently, Qi. et al 2020 analysed 13 human tissues by scRA sequencing and report that ACE2 mRNA was mainly expressed in the ileum enterocytes, kidney proximal tubules and lung AT2 cells. ACE2 mRNA was also detected but to a lesser extent in the colon enterocytes, esophagus and keratinocytes and minimally in the cholangiocytes (biliary cells of the liver). </span></span></p>
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</table>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Zunke 2017 - </span></span></span></span><a href="http://dx.doi.org/10.1016/j.bbamcr.2017.07.001"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">http://dx.doi.org/10.1016/j.bbamcr.2017.07.001</span></span></span></span></a></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Tipnis, 2000; doi: 10.1074/jbc.M002615200</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Donoghue 2000 - </span></span></span></span><a href="https://doi.org/10.1161/01.RES.87.5.e1"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">https://doi.org/10.1161/01.RES.87.5.e1</span></span></span></span></a></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Vickers 2002 - DOI 10.1074/jbc.M200581200</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Hamming 2007 – DOI: 10.1002/path.2162</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Rice 2004 - DOI 10.1042/BJ20040634</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Sodhi 218 - DOI 10.1042/BJ20040634</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Fraga-Silva et al., 2011: 10.1590/S1807-59322011000500021</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Qi. et al 2020 - doi.org/10.1016/j.bbrc.2020.03.044</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Ren 2006 - </span></span></span></span><span style="font-size:9.0pt"><span style="font-family:"AdvP4AD05B",serif"><span style="color:#242021">DOI </span></span></span><span style="font-size:9.0pt"><span style="font-family:"AdvP4AD059",serif"><span style="color:#242021">10.1099/vir.0.81749-0</span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Warner 2005 - doi: 10.1074/jbc.M508914200</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Ziegler 2020 - </span></span></span></span><span style="font-size:9.0pt"><span style="font-family:"AdvPSHN-M",serif"><span style="color:#0098d1">doi.org/10.1016/j.cell.2020.04.035</span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Yuan 2007 - DOI 10.1074/jbc.M705495200</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Garvin et al. eLife 2020; 9:e59177. DOI: </span></span></span></span><a href="https://doi.org/10.7554/eLife.59177"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">https://doi.org/10.7554/eLife.59177</span></span></span></span></a></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><a href="https://pubmed.ncbi.nlm.nih.gov/?term=van+de+Veerdonk+FL&cauthor_id=32338605"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">van de Veerdonk</span></span></span></span></a><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121"> 2020 - </span></span></span></span><a href="https://doi.org/10.7554/elife.57555"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">10.7554/eLife.57555</span></span></span></span></a></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Nicolau et al., (2020) </span></span></span></span><a href="https://doi.org/10.1016/j.mehy.2020.109886"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">https://doi.org/10.1016/j.mehy.2020.109886</span></span></span></span></a></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Jiqi Wang 2020 -/doi.org/10.1016/j.pharmthera.2020.107628</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Ziegler, 2020 - </span></span></span></span><a href="https://doi.org/10.1016/j.cell.2020.04.035"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">https://doi.org/10.1016/j.cell.2020.04.035</span></span></span></span></a></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Lu and Sun, 2020 - DOI 10.1074/jbc.RA120.015303</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Saponaro 2020 - doi: 10.3389/fmolb.2020.588618</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Glinsky 2020, unreviewed pre-print </span></span></span></span><a href="https://arxiv.org/abs/2003.13665v1"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">arXiv:2003.13665v1</span></span></span></span></a></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Patel 2014 - dx.doi.org/10.1016/j.yjmcc.2013.11.017</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Roca-Ho, 2017 - doi:10.3390/ijms18030563</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Xie et al., 2006 - doi: </span></span></span></span><a href="https://dx.doi.org/10.1016%2Fj.lfs.2005.09.038"><span style="font-size:8.0pt"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">10.1016/j.lfs.2005.09.038</span></span></span></a></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Lu and Sun, 2020 - DOI 10.1074/jbc.RA120.015303</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Liu 2014 - http://dx.doi.org/10.1016/j.virusres.2014.03.010</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Yang 2014 - DOI: 10.1038/srep07027</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Zou 2014 - DOI: 10.1038/ncomms4594</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Koka 2008 - DOI: 10.2353/ajpath.2008.070762</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Glowacka 2010: </span></span></span></span><span style="font-size:8.0pt"><span style="font-family:Dutch801BT-Roman"><span style="color:#242021">doi:10.1128/JVI.01248-09</span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="font-family:Dutch801BT-Roman"><span style="color:#242021">Guy </span></span></span><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">2008: 10.1113/expphysiol.2007.040139</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Peng Jia 2009: 10.1152/ajplung.00071.2009</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Lambert 2008: 10.1016/j.febslet.2007.11.085</span></span></span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:8.0pt"><span style="background-color:white"><span style="font-family:"Quattrocento Sans""><span style="color:#212121">Hashimoto 2012: 0.1038/nature11228</span></span></span></span></span></span></p>
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2021-03-31T04:33:122023-02-18T12:20:439b0253d7-7cfe-44a3-830a-13a1a24e4775703c0fd7-14ee-4815-9454-aaa55d95b33b2020-03-17T06:17:052020-03-17T06:17:05703c0fd7-14ee-4815-9454-aaa55d95b33bb4a9ef7b-1b13-4b5e-9d84-e5a0a8607bd92022-03-03T11:35:252022-03-03T11:35:25b4a9ef7b-1b13-4b5e-9d84-e5a0a8607bd9ca5e1788-61a5-45e5-9895-497d653cbaea2021-04-10T11:45:462021-04-10T11:45:46ca5e1788-61a5-45e5-9895-497d653cbaeac8059d48-3d8e-4e5d-aabe-f4f7627d21682021-04-10T11:46:102021-04-10T11:46:10c8059d48-3d8e-4e5d-aabe-f4f7627d21689a5cbf70-9e91-449f-964e-d031f6411f322021-03-30T13:01:132021-03-30T13:01:139a5cbf70-9e91-449f-964e-d031f6411f325dd2d1d1-2b5e-4987-bdba-7af584fa0a492021-03-30T12:50:092021-03-30T12:50:095dd2d1d1-2b5e-4987-bdba-7af584fa0a491c41d870-3351-4e3f-927c-9565c7af31d62020-05-15T18:00:132020-05-15T18:00:13Binding to ACE2 leading to lung fibrosisBinding to ACE2 leads to lung fibrosis<p>Young Jun Kim<sup>1</sup>, Ian Choi<sup>1</sup>, Jihun Yang<sup>2</sup>, Chung Seok<sup>2,3</sup> Brigitte Landesmann<sup>4</sup>, Laure-Alix Clerbaux<sup>4</sup> and Penny Nymark<sup>5</sup></p>
<p><sup>1</sup>Korea Institute of Science and Technology (KIST) Europe, Saarbrücken 66123, Germany, <sup>2</sup> NEXT&BIO, South Korea, <sup> 3</sup>KU-KIST Graduate School of Converging Science and Technology, South Korea <sup>4</sup> F3 Chemical Safety and Alternative Methods Unit incorporating EURL ECVAM, Directorate F – Health, Consumers and Reference Materials Joint Research Centre, European Commission <sup>5</sup> Institute of Environmental Medicine, Karolinska Institutet, Solna, Sweden </p>
Open for comment. Do not citeUnder DevelopmentIncluded in OECD Work Plan1.96<p>Lung fibrosis has a distinct point in idiopathic pulmonary fibrosis from the renin-angiotensin pathway. this system is reported in many works of literature to share many immune/inflammatory responses to lung damage. When ACE2 activity is inhibited, Ang II is not effectively converted into Ang-(1-7). Because of this, the levels of proinflammatory Ang II are increased and accumulated, while the levels of anti-inflammatory Ang-(1-7) are reduced. Most importantly, the Inhibition of ACE2 was shown to enhance the level of Ang II peptides which is a ligand for type 1 angiotensin receptor (AT1R) and is considered one of the risk factors for lung fibrosis, vasoconstriction, endothelial dysfunction, and cell death. The imbalance of the renin-angiotensin system (RAS) plays a critical role in the fibrogenesis and inflammation damage of many organs. Especially the inhibition of membrane ACE-2 enzymatic activity has shown promising potential in the Molecular initiation event which leads to pulmonary fibrosis. This AOP describes the role of ACE-2 in fibrotic damage of the lung as an adverse outcome through the fibrogenic components, proinflammatory cytokines, and oxygen deficiency.</p>
<p>ACE2 is an essential enzyme of blood pressure regulation in the renin-angiotensin system. ACE2 is primarily expressed on type II alveolar epithelial cells within the respiratory system. Angiotensin-converting enzyme (ACE) synthesizes the dominant vasoconstriction, inflammatory and profibrotic angiotensin II (Ang II) through its carboxypeptidase function on the decapeptide angiotensin I. In the meantime, Angiotensin-converting enzyme 2 (ACE2) is an exopeptidase that catalyzes the conversion of angiotensin Il to the conversion of angiotensin 1-7 function as vasodilation, anti-inflammation, and anti-fibrotic. This AOP describes the dysfunction of membrane ACE2, which results in a high level of angiotensin Ang II synthesized by ACE, which can further lead to pulmonary fibrosis by excessive collagen deposition as the most potent profibrotic factor.</p>
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adjacentModerateHighadjacentHighHighadjacentModerateModerateadjacentModerateModerateadjacentModerateModerateadjacentModerateModerateadjacentNot SpecifiedLowModerateNot Otherwise SpecifiedHighHighHighHighHighHigh2020-03-01T08:07:542023-04-29T13:02:17