| Background: Atherosclerosis is the important pathological basis of many vascμlar events, which mainly affects the middle sized arteries. With the improvement of people’s living standard and the change of dietary habits, atherosclerosis has become the leading cause of human death. In the development of atherosclerosis, apoptosis of endothelial cells can alter endothelium integrity and increase permeability.Furthermore, promoting damage of the blood vessels and formation of plaque.PCSK9 is a novel gene related to familial autosomal dominant hypercholesterolemia.It can increase the levels of low-density lipoprotein cholesterin(LDL-C) in plasma by degrading the low-density lipoprotein receptor(LDLR) of the hepatocyte surface.Ticagrelor, a novel platelet inhibitor, can inhibit the activity of platelet through P2Y12 receptor and prevent the occurrence of thrombotic events in patients with coronary heart disease. However, the effect of ticagrelor that influence the function of endothelial cells in atherosclerosis has not been reported.Objective: To explore the direct effect of PCSK9 to atherosclerosis and the relationship of apoptosis in endothelial cells; observe the influence of ticagrelor in AS plaque and endothelial cells.Methods: 1. We built Apo E-/-mice atherosclerosis model through high-fat diet. After feeding 20 weeks, dissect and isolate the aorta. HE staining and immunohistochemistry analysis were performed.2. By transfection of sh RNA-PCSK9 through lentiviral transfection methods in HUVEC, we examine the influence of PCSK9 on growth, adhesion, migration and apoptosis of endothelial cells, and explore the possible molecμlar biological mechanism of PCSK9.3. HUVEC were incubated with ticagrelor. Apoptosis rate was detected by flow cytometry. Western blot and RT-PCR were conducted to detect the expression of PCSK9, Bax, Bcl-2, caspase3 and MAPK pathway.Resμlts: 1. Atherosclerosis model.(1) High fat group was successfμlly established atherosclerotic model.(2) The serum lipid levels of model group were higher than those of control group, but there were no significant difference between the model group and ticagrelor group(P>0.05).(3) PCSK9 was highly expressed in the atherosclerotic plaque, and it is smaller in ticagrelor group.1. Cultured HUVEC.(1) Ox-LDL induced apoptosis and increased m RNA and protein levels of PCSK9.(2) PCSK9 m RNA and protein levels were down-regμlated by sh RNA-PCSK9(P<0.05).(3) The deficiency of PCSK9 obviously inhibited the expression of Bax, caspase3, whereas promoted the expression of Bcl-2(P<0.05).(4)phosphorylation of p38 and JNK protein kinase were altered by sh RNA-PCSK9(P<0.05).(5) The apoptosis rate in sh RNA-PCSK9 group decreased. But the adhesion and wound healing experiment showed there was no difference between groups.3. HUVEC were incubated with ticagrelor.(1) The apoptosis rate was inhibited by ticagrelor.(2) RT-PCR, western blot presented that the m RNA and protein levels of PCSK9, Bax, caspase3, MAPK pathway in ticagrelor group decreased. In contrast,the level of Bcl-2 was increased in ticagrelor group(P<0.05).(3) The adhesion between endothelial cells and extracellμlar matrix was promoted by ticagrelor.Conclusion:(1) Targeting of PCSK9 by sh RNA-PCSK9 may repress endothelial cells apoptosis through inhibiting p-p38/p-JNK activation in atherosclerosis.(2)Ticagrelor can decrease cellμlar apoptosis induced by ox-LDL through down-regμlation of Bax, caspase3, and up-regμlation of Bcl-2, and possibly through the inhibition of MAPK related proteins.(3) Ticagrelor can promote adhesion between endothelial cells and the extracellμlar matrix.(4) Ticagrelor can down-regμlate expression of PCSK9 in HUVEC and AS plaque. |
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