Role of Toll -like receptor 4 in lipopolysaccharide-induced platelet apoptosis

doi:10.3969/j.issn.1002-1949.2014.12.007

Abstract：Objecitve To explore the effect of platelet apoptosis induced by lipopolysaccharide (LPS)and the role of Toll-like receptor 4 (TLR4) in this process.Methods Fresh venous blood was drawn from healthy human volunteers to isolate platelet -rich plasma (PRP ) and prepare washed platelets.The washed platelets were randomly divided into 4 groups:the control group (group C), the LPS group (group L), the TLR4mAb pretreatment group (group P) and the thrombin group (group T). Each group was first incubated with the FcγRⅡ monoclonal antibody ( 20 min, room temperature ) . Platelets in group P were pretreated with TLR4mAb, while others with equal amount of MTB (30 min, room temperature ) .Then platelets in group L and P were incubated with LPS for 30 min at room temperature, while platelets in group T with thrombin and platelets in group C with MTB .Platelet lysate was prepared by cell lysis buffer .The expression of apoptosis proteins was detected by Human Apoptosis Antibody Array.Comparison between groups was carried out by using the RayBio ? Analysis Tool. Results Human platelets can express many apoptosis -related proteins .Compared to group C , 36 kinds of apoptosis-related proteins were up -regulated in group L (fold change>1.50), including 16 pro-apoptotic members , 8 anti -apoptotic members and 12 proteins working both ways .29 kinds of proteins increased in group T (fold change >1.50) than group C, which included 15 pro-apoptotic members, 6 anti-apoptotic members and 8 proteins working both ways .29 kinds of apoptosis -related proteins in group P were lower than that in group L (fold change<0.67).But 17 kinds of apoptosis -related proteins in group P were still higher than those in group C (fold change>1.50).Conclusion Apoptosis of human platelet can be induced by LPS in vitro .This effect can be weakened by blocking the pathway of LPS-TLR4.