Modulation of platelet activation in vitro by thrombopoietin.

摘要: Effect of human recombinant thrombopoietin (TPO) on platelet activation in vitro was studied. Although TPO itself did not cause aggregation, it upregulated ADP-induced especially the second wave aggregation. This effect dose-dependent for up to 5 ng/ml TPO. When platelets were activated by epinephrine, collagen, or alpha-thrombin, similar observed. However, affect A23187- PMA-induced suggesting that may have modulated signal transduction pathway upstream inositol 1,4,5-trisphosphate and diacylglycerol production. also thrombin-induced alpha-granule secretion. To clarify involvement protein tyrosine phosphorylation, and/or suboptimal concentration ADP, then phosphorylation detected immunoblot analysis, using anti-phosphotyrosine monoclonal antibody. caused significant 146, 130, 122, 108, 97, 94, 88 kDa proteins. Further, antibodies against molecules immunoprecipitation, we observed Jak2 Tyk2 after TPO-stimulation. The results present experiment clearly indicate directly intracellular pathway.