PTEN deficiency facilitates collagen/GPVI-induced platelet activation. (A) Western blot results show that both human and mouse platelets express PTEN. (B) After poly(I:C) treatment for 10 days, washed platelets were prepared from Ptenloxp-loxp/Mx1-Cre− (designated PTEN+/+) and Ptenloxp-loxp/Mx1-Cre+ (designated PTEN−/−), Western blot results showed that PTEN was depleted in PTEN−/− platelets. (C) Hematopoietic depletion of PTEN caused thrombocytosis (Pten+/+ mouse platelet counts 284.8 ± 47.7 × 109/mL, Pten−/− mouse platelet counts 356.8 ± 51.4 × 109/mL). *P < .05. n = 20. (D) The bleeding time in the Pten+/+ mice (206 ± 71 seconds) was statistically different from Pten−/− mice (113 ± 35 seconds). *P < .05. n = 10. (E) PTEN deficiency facilitated collagen-induced platelet ATP secretion. Data were obtained from at least 3 tests. Bars represent the mean plus or minus SD. (F) PTEN deficiency facilitated collagen-induced platelet aggregation. (G) A total of 2 μg/mL collagen-induced platelet aggregation was dependent on GPVI/FcR-γ chain function. (H) Collagen-induced Akt phosphorylation was enhanced in PTEN-deficient platelets. (I) A total of 2 μg/mL collagen-induced Akt phosphorylation was dependent on GPVI/FcR-γ chain function.
