{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T05:38:28Z","timestamp":1789623508217,"version":"build-2803163510"},"reference-count":30,"publisher":"Georg Thieme Verlag KG","funder":[{"DOI":"10.13039\/100000049","name":"National Institute on Aging","doi-asserted-by":"crossref","award":["1R01AG068623"],"award-info":[{"award-number":["1R01AG068623"]}],"id":[{"id":"10.13039\/100000049","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Thromb Haemost"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Human platelets express protease-activated receptor (PAR) 1 and 4 on the platelet membrane. PAR1 activation is crucial for hemostasis, while PAR4 activation produces a prolonged pro-inflammatory platelet response. Once activated, the PAR receptors cause platelet activation and aggregation. The PARs are activated by proteolytic cleavage of their N-terminus, revealing a new N-terminus called the tethered ligand. This tethered ligand folds back and activates the receptor. PAR1 and PAR4 differ in their tethered ligand sequence as well as their signaling cascades; however, they are both activated by various serine proteases, specifically thrombin.<\/jats:p>\n                  <jats:p>Much is known about PAR4 activation via thrombin activation; however, little is known about activation by other proteases. Thrombin cleavage of PAR4 and subsequent activation leads to G proteins, G\u03b1q and G\u03b112\/13, and \u03b2-arrestin signaling. The objective of this study is to characterize trypsin activation of PAR4 on human platelets.<\/jats:p>\n                  <jats:p>Platelets were isolated from the whole blood of healthy human volunteers by centrifugation. Platelets were utilized in flow cytometry assays, calcium mobilization assays, and western blot experiments to characterize trypsin activation of human platelets.<\/jats:p>\n                  <jats:p>Here, we demonstrate that trypsin activates human platelets solely through PAR4. Trypsin activation of PAR4 signaling through both G\u03b1q and G\u03b112\/13 is as effective as \u03b1-thrombin activation of PAR4.<\/jats:p>\n                  <jats:p>Thrombin may be the main protease to activate PAR4 under typical conditions; however, under pathological conditions such as acute pancreatitis (AP), trypsin activation of PAR4 may be a main driver of platelet activation and disease progression.<\/jats:p>","DOI":"10.1055\/a-2747-9083","type":"journal-article","created":{"date-parts":[[2025,11,18]],"date-time":"2025-11-18T00:10:23Z","timestamp":1763424623000},"source":"Crossref","is-referenced-by-count":3,"title":["Trypsin Activates Human Platelets via Proteolytic Cleavage of Protease-Activated Receptor 4"],"prefix":"10.1055","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0281-3326","authenticated-orcid":false,"given":"Emma M.","family":"Webb","sequence":"additional","affiliation":[{"name":"Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kendal","family":"Seymour","sequence":"additional","affiliation":[{"name":"Department of Neuroscience, Vanderbilt University, Nashville, Tennessee, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Heidi E.","family":"Hamm","sequence":"additional","affiliation":[{"name":"Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, United States"},{"name":"Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"194","published-online":{"date-parts":[[2025,12,4]]},"reference":[{"issue":"01","key":"ref1","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1053\/ejvs.2002.1794","article-title":"Increased platelet aggregation and activation in peripheral arterial disease","volume":"25","author":"P A Robless","year":"2003","journal-title":"Eur J Vasc Endovasc Surg"},{"issue":"06","key":"ref2","doi-asserted-by":"crossref","first-page":"509","DOI":"10.1177\/1074248419861437","article-title":"Role of platelet activation and oxidative stress in the evolution of myocardial infarction","volume":"24","author":"E Fuentes","year":"2019","journal-title":"J Cardiovasc Pharmacol Ther"},{"issue":"05","key":"ref3","doi-asserted-by":"crossref","first-page":"270","DOI":"10.1097\/00062752-200109000-00002","article-title":"Mechanisms of platelet aggregation","volume":"8","author":"B Savage","year":"2001","journal-title":"Curr Opin Hematol"},{"issue":"01","key":"ref4","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1093\/eurheartj\/ehp504","article-title":"Platelet thrombin receptor antagonism and atherothrombosis","volume":"31","author":"D J Angiolillo","year":"2010","journal-title":"Eur Heart J"},{"key":"ref5","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1186\/s12959-019-0194-8","article-title":"Protease-activated receptors (PARs): mechanisms of action and potential therapeutic modulators in PAR-driven inflammatory diseases","volume":"17","author":"D M Heuberger","year":"2019","journal-title":"Thromb J"},{"issue":"20","key":"ref6","doi-asserted-by":"crossref","first-page":"2952","DOI":"10.1111\/bph.13455","article-title":"Protease-activated receptor 4: from structure to function and back again","volume":"173","author":"S L French","year":"2016","journal-title":"Br J Pharmacol"},{"issue":"14","key":"ref7","doi-asserted-by":"crossref","first-page":"4000","DOI":"10.1111\/febs.16406","article-title":"The Yin-Yang roles of protease-activated receptors in inflammatory signalling and diseases","volume":"289","author":"X Zhuo","year":"2022","journal-title":"FEBS J"},{"key":"ref8","doi-asserted-by":"crossref","first-page":"67","DOI":"10.3389\/fendo.2014.00067","article-title":"Biased signaling of protease-activated receptors","volume":"5","author":"P Zhao","year":"2014","journal-title":"Front Endocrinol (Lausanne)"},{"issue":"10","key":"ref9","doi-asserted-by":"crossref","first-page":"1809","DOI":"10.1161\/ATVBAHA.117.310068","article-title":"Protease-activated receptor-1 signaling the big picture","volume":"37","author":"R Flaumenhaft","year":"2017","journal-title":"Arterioscler Thromb Vasc Biol"},{"issue":"26","key":"ref10","doi-asserted-by":"crossref","first-page":"19728","DOI":"10.1074\/jbc.M909960199","article-title":"Structure-function analysis of protease-activated receptor 4 tethered ligand peptides. Determinants of specificity and utility in assays of receptor function","volume":"275","author":"T R Faruqi","year":"2000","journal-title":"J Biol Chem"},{"issue":"06","key":"ref11","doi-asserted-by":"crossref","first-page":"1241","DOI":"10.1160\/TH13-03-0189","article-title":"Trypsin causes platelet activation independently of known protease-activated receptors","volume":"110","author":"Y Mao","year":"2013","journal-title":"Thromb Haemost"},{"issue":"14","key":"ref12","doi-asserted-by":"crossref","first-page":"13532","DOI":"10.1074\/jbc.M312090200","article-title":"Trypsin IV, a novel agonist of protease-activated receptors 2 and 4","volume":"279","author":"G S Cottrell","year":"2004","journal-title":"J Biol Chem"},{"issue":"05","key":"ref13","doi-asserted-by":"crossref","first-page":"1236","DOI":"10.1111\/jth.15669","article-title":"Human and mouse PAR4 are functionally distinct receptors: studies in novel humanized mice","volume":"20","author":"S A Renna","year":"2022","journal-title":"J Thromb Haemost"},{"issue":"02","key":"ref14","doi-asserted-by":"crossref","first-page":"F219","DOI":"10.1152\/ajprenal.00162.2023","article-title":"Role of protease-activated receptor 4 in mouse models of acute and chronic kidney injury","volume":"326","author":"K Erreger","year":"2024","journal-title":"Am J Physiol Renal Physiol"},{"issue":"05","key":"ref15","first-page":"325","article-title":"Pancreatic cancer and thromboembolic disease, 150 years after Trousseau","volume":"4","author":"D Ansari","year":"2015","journal-title":"Hepatobiliary Surg Nutr"},{"issue":"01","key":"ref16","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1124\/mol.116.106666","article-title":"Contributions of protease-activated receptors PAR1 and PAR4 to thrombin-induced GPIIbIIIa activation in human platelets","volume":"91","author":"M T Duvernay","year":"2017","journal-title":"Mol 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Merali","year":"2022","journal-title":"Platelets"},{"issue":"13","key":"ref20","doi-asserted-by":"crossref","first-page":"8843","DOI":"10.1021\/acs.jmedchem.2c00359","article-title":"Discovery of two novel antiplatelet clinical candidates (BMS-986120 and BMS-986141) that antagonize protease-activated receptor 4","volume":"65","author":"E S Priestley","year":"2022","journal-title":"J Med Chem"},{"issue":"01","key":"ref21","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1038\/sj.bjp.0705008","article-title":"Unproductive cleavage and the inactivation of protease-activated receptor-1 by trypsin in vascular endothelial cells","volume":"138","author":"T Nakayama","year":"2003","journal-title":"Br J Pharmacol"},{"issue":"05","key":"ref22","doi-asserted-by":"crossref","first-page":"762","DOI":"10.1111\/j.1365-2141.2007.06503.x","article-title":"Higher thrombin concentrations are required to induce platelet apoptosis than to induce platelet activation","volume":"136","author":"V 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Soslau","year":"2004","journal-title":"Platelets"},{"issue":"26","key":"ref26","doi-asserted-by":"crossref","first-page":"25048","DOI":"10.1074\/jbc.M414090200","article-title":"Functional selectivity of G protein signaling by agonist peptides and thrombin for the protease-activated receptor-1","volume":"280","author":"J N McLaughlin","year":"2005","journal-title":"J Biol Chem"},{"issue":"04","key":"ref27","doi-asserted-by":"crossref","first-page":"439","DOI":"10.1007\/s11605-007-0128-9","article-title":"Platelet function in acute experimental pancreatitis","volume":"11","author":"T Hackert","year":"2007","journal-title":"J Gastrointest Surg"},{"issue":"01","key":"ref28","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1159\/000077024","article-title":"Alterations of platelet function, number and indexes during acute pancreatitis","volume":"4","author":"K Mimidis","year":"2004","journal-title":"Pancreatology"},{"issue":"11","key":"ref29","doi-asserted-by":"crossref","first-page":"1189","DOI":"10.1111\/j.1365-2982.2009.01310.x","article-title":"Protease-activated receptor-4 (PAR 4): a role as inhibitor of visceral pain and hypersensitivity","volume":"21","author":"C Aug\u00e9","year":"2009","journal-title":"Neurogastroenterol Motil"},{"issue":"01","key":"ref30","doi-asserted-by":"crossref","first-page":"206","DOI":"10.1186\/s12876-023-02837-w","article-title":"Clinical significance of reactive thrombocytosis in the course of acute pancreatitis","volume":"23","author":"N Chiba","year":"2023","journal-title":"BMC Gastroenterol"}],"container-title":["Thrombosis and 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