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Role of P ‐selectin and P ‐selectin glycoprotein ligand‐1 interaction in the induction of tissue factor expression on human platelets after incubation with porcine aortic endothelial cells
Author(s) -
Ezzelarab Mohamed B.,
Liu Yueh Wei,
Lin Chih Che,
Long Cassandra,
Ayares David,
Dorling Anthony,
Cooper David K. C.
Publication year - 2013
Publication title -
xenotransplantation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.052
H-Index - 61
eISSN - 1399-3089
pISSN - 0908-665X
DOI - 10.1111/xen.12068
Subject(s) - tissue factor , platelet , xenotransplantation , microbiology and biotechnology , p selectin , selectin , coagulation , platelet activation , biology , glycoprotein , antibody , immunology , andrology , transplantation , medicine , inflammation
Development of coagulation disorders remains a major challenge in pig‐to‐primate organ xenotransplantation. Our previous studies demonstrated that porcine aortic endothelial cells ( pAEC ) activate human platelets to express tissue factor ( TF ). In this study, we investigated the molecular interaction between human platelets and p AEC to identify possible targets for further genetic modification and/or systemic therapy. Human platelets were incubated with p AEC from wild‐type ( WT ), α1,3‐galactosyltransferase gene‐knockout ( GTKO ), and GTKO pigs expressing human CD 46, after which the platelets were analyzed for TF expression, TF m RNA level and TF function. p AEC were analyzed for von W illebrand factor (v WF ) expression and m RNA level as well. Neutralizing antibodies for P ‐selectin and P ‐selectin glycoprotein ligand‐1 ( PSGL ‐1) were used to block the molecular interaction between platelets and p AEC . GTKO and GTKO / CD 46 p AEC ‐activated human platelets to induce human TF activity equivalently to WT p AEC . Simultaneously, after incubation with p AEC , platelets co‐expressed TF and P ‐selectin. TF expression was blocked when p AEC and platelets were pre‐incubated with anti‐human P ‐selectin or anti‐human PSGL ‐1 antibodies, but not by anti‐porcine P ‐selectin antibody. Activated p AEC up‐regulated TF on platelets through the interaction of porcine v WF with the human GPI b receptor. Up‐regulation of TF on human platelets by GTKO and GTKO / CD 46 pAEC was comparable to that by WT p AEC , which is associated with concomitant expression of P ‐selectin and PSGL ‐1, forming an auto‐augmented loop of p AEC and platelet activation. Blocking of P ‐selectin and PSGL ‐1 interaction may be required to prevent up‐regulation of recipient TF in vivo after organ xenotransplantation.