OBJECTIVE: To investigate the expression of protease-activated receptors (PARs), their potential regulation by anticardiolipin antibodies (aCL), and their association with the expression of other molecules relevant to thrombosis in monocytes obtained from 62 patients with primary antiphospholipid syndrome (APS). METHODS: Monocytes were isolated from peripheral blood mononuclear cells by magnetic depletion of nonmonocytes. Expression of tissue factor (TF) and PARs 1-4 genes was measured by quantitative real-time reverse transcription-polymerase chain reaction. Cell surface TF and PARs 1-4 expression was analyzed by flow cytometry. For in vitro studies, purified normal monocytes were incubated with purified APS patient IgG, normal human serum IgG, or lipopolysaccharide, in the presence or absence of specific monoclonal antibodies anti-PAR-1 (ATAP2) or anti-PAR-2 (SAM11) to test the effect of blocking the active site of PAR-1 or PAR-2. RESULTS: Analysis of both mRNA and protein for the 4 PARs revealed significantly increased expression of PAR-2 as compared with the control groups. PAR-1 was significantly overexpressed in APS patients with thrombosis and in the control patients with thrombosis but without APS. PAR-3 expression was not significantly altered. PAR-4 expression was absent in all groups analyzed. In addition, we demonstrated a correlation between the levels of PAR-2 and the titers of IgG aCL, as well as parallel behavior of TF and PAR-2 expression. In vitro, IgG from APS patients significantly increased monocyte expression of PAR-1 and PAR-2. Inhibition studies suggested that there was direct cross-talk between TF and PAR-2, such that inhibition of PAR-2 prevented the aCL-induced expression of TF. CONCLUSION: These results provide the first demonstration of increased expression of PARs in monocytes from patients with APS. Thus, PAR antagonists might have therapeutic potential as antithrombotic agents in APS.
OBJECTIVE: To investigate the expression of protease-activated receptors (PARs), their potential regulation by anticardiolipin antibodies (aCL), and their association with the expression of other molecules relevant to thrombosis in monocytes obtained from 62 patients with primary antiphospholipid syndrome (APS). METHODS: Monocytes were isolated from peripheral blood mononuclear cells by magnetic depletion of nonmonocytes. Expression of tissue factor (TF) and PARs 1-4 genes was measured by quantitative real-time reverse transcription-polymerase chain reaction. Cell surface TF and PARs 1-4 expression was analyzed by flow cytometry. For in vitro studies, purified normal monocytes were incubated with purified APSpatient IgG, normal human serum IgG, or lipopolysaccharide, in the presence or absence of specific monoclonal antibodies anti-PAR-1 (ATAP2) or anti-PAR-2 (SAM11) to test the effect of blocking the active site of PAR-1 or PAR-2. RESULTS: Analysis of both mRNA and protein for the 4 PARs revealed significantly increased expression of PAR-2 as compared with the control groups. PAR-1 was significantly overexpressed in APSpatients with thrombosis and in the control patients with thrombosis but without APS. PAR-3 expression was not significantly altered. PAR-4 expression was absent in all groups analyzed. In addition, we demonstrated a correlation between the levels of PAR-2 and the titers of IgG aCL, as well as parallel behavior of TF and PAR-2 expression. In vitro, IgG from APSpatients significantly increased monocyte expression of PAR-1 and PAR-2. Inhibition studies suggested that there was direct cross-talk between TF and PAR-2, such that inhibition of PAR-2 prevented the aCL-induced expression of TF. CONCLUSION: These results provide the first demonstration of increased expression of PARs in monocytes from patients with APS. Thus, PAR antagonists might have therapeutic potential as antithrombotic agents in APS.
Authors: A Crilly; E Burns; M B Nickdel; J C Lockhart; M E Perry; P W Ferrell; D Baxter; J Dale; L Dunning; H Wilson; J S Nijjar; J A Gracie; W R Ferrell; I B McInnes Journal: Ann Rheum Dis Date: 2012-01-30 Impact factor: 19.103
Authors: Nadine Müller-Calleja; Anne Hollerbach; Svenja Ritter; Denise G Pedrosa; Dennis Strand; Claudine Graf; Christoph Reinhardt; Susanne Strand; Philippe Poncelet; John H Griffin; Karl J Lackner; Wolfram Ruf Journal: Blood Date: 2019-08-21 Impact factor: 22.113
Authors: Katie Poulton; Vera M Ripoll; Charis Pericleous; Pier Luigi Meroni; Maria Gerosa; Yiannis Ioannou; Anisur Rahman; Ian P Giles Journal: Am J Reprod Immunol Date: 2014-12-02 Impact factor: 3.886
Authors: Vera M Ripoll; Anastasia Lambrianides; Silvia S Pierangeli; Katie Poulton; Yiannis Ioannou; Wendy E Heywood; Kevin Mills; David S Latchman; David A Isenberg; Anisur Rahman; Ian P Giles Journal: Blood Date: 2014-10-09 Impact factor: 22.113