Objective To explore the role of angiotensin Ⅱ type 1 receptor(AT1R)in the promotion of atherosclerosis by trimethylamine N-oxide(TMAO).Methods Molecular docking was used to predict the possible interaction between TMAO and AT1R.Twenty-one 6-week-old ApoE-/-mice were randomly divided into control group,TMAO group,and TMAO + telmisartan group,with 7 mice in each group.The TMAO group was fed with 1%choline in the diet to replicate the high TMAO blood model.The TMAO + telmisartan group was treated with telmisartan 10 mg/(kg·d)by gavage.After 12 weeks,blood was collected,and plasma TMAO levels were determined by high-performance liquid chromatography-tandem mass spectrometry.Oil Red O staining was used to determine the plaque area at the aortic root.Immunohistochemistry was used to detect the infiltration of inflammatory factors monocyte chemoattractant protein-1(MCP-1)and interleukin-6(IL-6)in the plaque.AT1R expression plasmids were constructed,transfected into 293T cells,and treated with TMAO(200 μmol/L)or TMAO(200 μmol/L)+ telmisartan(1 μmol/L)for 0,5,10,15,30,and 60 min.The activation of the downstream signaling pathways ERK and PKC was detected.Results Molecular docking predicted a direct binding site between TMAO and AT1R.The proportion of plaque area at the aortic root,expression of MCP-1,and IL-6 in the plaque were statistically different among the three groups(P<0.05).The TMAO group showed an increase in the proportion of plaque area at the aortic root and an elevation of MCP-1 and IL-6 expression compared to the control group(P<0.05),while the telmisartan group showed a decrease compared to the TMAO group(P<0.05).The expression of AT1R,p-ERK1/2,and p-PKC in aortic tissues differed significantly among the three groups(P<0.05).The TMAO group increased significantly compared to the control group(P<0.05),while the telmisartan group decreased compared to the TMAO group(P<0.05).In 293T cells transfected with AT1R plasmids,the relative expression of p-ERK1/2 and p-PKC protein at different time points in the TMAO group(200 μmol/L)was statistically different(P<0.05).Compared with 0 min,the relative expression of p-ERK1/2 increased at 15 and 30 min(P<0.05),and the relative expression of p-PKC increased at 10 and 15 min(P<0.05).After treatment with telmisartan(1 μmol/L),there was no statistically significant difference in the relative expression of p-ERK1/2 and p-PKC at each time point(P>0.05).Conclusion The mechanism by which TMAO exacerbates atherosclerosis in ApoE-/-mice may involve its action on AT1R.
trimethylamine oxideangiotensin Ⅱ type 1 receptoratherosclerosis
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