The neutrophil serine protease PR3 induces shape change of platelets via the Rho/Rho kinase and Ca2+ signaling pathways
2014 (English)In: Thrombosis Research, ISSN 0049-3848, E-ISSN 1879-2472, Vol. 134, no 2, 418-425 p.Article in journal (Refereed) Published
Introduction: Proteinase 3 (PR3) is released from neutrophil azurophilic granules and exerts complex effects on the inflammatory process. PR3 catalyzes the degradation of a number of macromolecules, but the consequences on blood cells are less well defined. In the present study, the effect of PR3 on human platelets was thoroughly investigated. Methods: The experiments were performed on washed platelets freshly isolated from blood donated by healthy human volunteers. Platelets shape change and aggregation was measured on a Chrono-Log aggregometer. The phosphorylated form of MYPT1 was visualized by immunostaining. Platelet activation was further evaluated by flow cytometry. Results: PR3 induced platelet shape change but not aggregation. Flow cytometry analysis showed that PR3 induced no P-selectin expression or binding of fibrinogen to the platelets, and it did not change the activation in response to PAR1- or PAR4-activating peptides or to thrombin. Furthermore, Fura-2 measurement and immuno-blotting analysis, respectively, revealed that PR3 stimulated small intracellular Ca2+ mobilization and Thr696-specific phosphorylation of the myosin phosphatase target subunit 1 (MYPT1). Separate treatment of platelets with the Rho/Rho kinase inhibitor Y-27632 and the intracellular Ca2+ chelator BAPTA/AM reduced the shape change induced by PR3 whereas concurrent treatment completely inhibited it. Conclusion: The data shows that the neutrophil protease PR3 is a direct modulator of human platelets and causes shape change through activation of the Rho/Rho kinase and Ca2+ signaling pathways. This finding highlights an additional mechanism in the complex interplay between neutrophils and platelets.
Place, publisher, year, edition, pages
Elsevier, 2014. Vol. 134, no 2, 418-425 p.
ANCA-associated vasculitis; Proteinase PR3; Platelet shape change; Rho/Rho kinase signaling pathway; Ca2+ signaling pathway
IdentifiersURN: urn:nbn:se:liu:diva-111292DOI: 10.1016/j.thromres.2014.06.001ISI: 000341309200035PubMedID: 24993595OAI: oai:DiVA.org:liu-111292DiVA: diva2:755332
Funding Agencies|Swedish Renal Foundation; Asp Foundation2014-10-142014-10-142015-03-13