[Abnormal structure and dysfunction of platelets in CD226 knockout mice]

Objective To study the regulatory effect of co-stimulatory molecule CD226 on platelet function in mice. Methods The 40-week-old CD226 knockout (CD226KO) mice were used as an experimental group and the wild wild-type (WT)C57BL/6 mice at the same age were designated as a control group. Caudal venous blood was taken for platelet counting. Tail tips of the mice were snipped for the bleeding time measurement. Ultrastructure of platelets was examined by transmission electron microscope. Carotid artery thrombosis model was established by the induction of ferric chloride in mice, to test the difference of platelet function in CD226KO and WT mice. Human platelet protein was harvested for immunoprecipitation (IP) and mass spectrometry analyses to screen the CD226-interactive proteins. Results Aged mice in CD226KO group had significantly lower platelet counts and longer bleeding time compared with the mice in WT group at the same age. Moreover, the scanning electron microscopic image of platelet also indicated that CD226 knockout induced the shrinkage and distortion of platelet endoplasmic reticulum. The FeCl₃-induced thrombosis model showed that the thrombosis time was significantly longer in CD226KO mice, and thrombus stability was significantly reduced. Mass spectrometry indicated that platelet CD226 interacted with BDNF, FABP5, ApoA1 and other proteins. Conclusion Knockout of CD226 gene significantly affects platelet function in mice, and CD226 molecules are involved in the exertion of biological activity of platelets.