Abstract: Objective To analyze the expression of miRNAs in stored apheresis platelets and their effects on protein levels associated with platelet aggregation. Methods Healthy male donor platelets were collected and stored at（22±2）℃. The expression profile and changes of miRNA in these platelets were detected by human miRNA array and qRT-PCR. Flow cytometry（FCM）was used to test P2Y12,VASP,GPⅡb/Ⅲa and apoptosis rate in stored platelets. Results Compared the microarray of microRNA expression in platelets stored on the 2nd with 5th days,47 miRNAs expression increased and 120 decreased. Compared the 8th storage day with 2nd day,28 miRNAs increased and 202 miRNAs decreased. Differentially expressed miRNAs were found to be associated with platelet activation,degranulation,PDGF receptor signaling pathway differentiation. As for miRNAs related to platelet aggregation,miR-155,miR-21-5p and miR-21-3p decreased on the 5th day of storage（P<0.05）,while let-7b,miR-223 and miR-3162 increased（P<0.05）. The apoptotic rate of apheresis platelets increased continuously with the increase of storage days. Proteins related to aggregation were also assayed, P2Y12 was activated and then induced the dephosphorylation of VASP. PLT GPⅡb/Ⅲa stayed relatively stable during storage. Conclusion miRNA expressions were found in banked platelets and the expressions changed over time. The changes of miRNA are associated with the corresponding protein level,and eventually lead to the change of platelet aggregation function. Some miRNA expression shows the potential role as biomarkers for platelet lesion during storage in blood bank condition.

Key words: Platelet, MicroRNA, Storage lesion, Apoptosis, GPⅡb/Ⅲa, VASP, P2Y12