The Role Of Cdc42 In Macrophage Activation And Foam Cell Forming In Atherosclerosis

BackgroundAtherosclerosis?AS?is a type of chronic inflammatory disease characterized by abnormal accumulation of lipids in vascular endothelial,which can induce severe diseases such as stroke,myocardial infarction,peripheral vascular disease,and kidney disease.It is believed that the aggregation and activation of macrophages and forming foam cells are the key pathological changes at the lesion site in the formation of atherosclerosis,the detail pathogenesis is not yet completely clear.According to reports,Cdc42 activation is involved in the migration and phagocytosis of macrophages during the inflammatory reaction,but the role of Cdc42 in the activation of atherosclerotic macrophages and the formation of foam cells has not been reported in detail.In this study,macrophage-specific knockout of Cdc42 gene mice were used to explore the effect and mechanism of macrophage Cdc42 in atherosclerosis.Experimental method1.ApoE-deficient mice were crossed with Lyz2Cre mice?myeloid-specific Cre recombinase-expressing mice?or Cdc42^fl/fl mice for multiple generations to obtain ApoE deletion&Myeloid specific knockout Cdc42 mice.2.Feeding 8-week-old ApoE^-/-Cdc42^fl/fl Lyz2cre⁺knockout mice and control(ApoE^-/-Cdc42^fl/fl LysMcre-)mice on the atherosclerotic diet?D12108C?for 16 weeks to establish the atherosclerosis model,record the changes of body weight weekly.3.Isolating the mouse aorta after 16 weeks feeding,staining with oil red,observing the plaque formation,and measuring the contents of cholesterol,triglyceride,HDL-C and LDL-C in the serum.4.Extracting the primary peritoneal macrophages,observing the phagocytosis in the macrophages under the stimulation of ox-LDL.5.RT-qPCR detection of the expression of lipid metabolism-related receptors ABCA1,CD36 and other genes in the macrophages.6.Western blot analysis of ABCA1,CD36,LXR-?and other related proteins in the macrophages.Experimental results1.Successfully constructing ApoE^-/-Cdc42 macrophage-specific knockout mice and estabolishing the atherosclerotic animal model by feeding the atherosclerotic diet.2.Macrophage-specific knockout of Cdc42 did not significantly affect the changes in the increasing of body weight and routine blood tests,but significantly aggravated atherosclerotic lesions in the atherosclerotic mice model.3.The chemotactic migration were inhibited,but the phagocytosis of ox-LDL were significantly enhanced in Cdc42 specifically knocking out macrophages.4.The expression of CD36 was significantly up-regulated and the expression of ABCA1 was inhibited in Cdc42 specifically knocking out macrophages.ConclusionUnder the background of ApoE deficiency,specifically knocking out macrophage Cdc42 significantly aggravated the atherosclerosis lesions in the mice.At the cellular level,knockout of Cdc42 inhibited the chemotaxis of macrophages.In the meantime,knockout of Cdc42 significantly promoted the phagocytosis of ox-LDL and inhibited the excretion of cholesterol by upregulating CD36 or down-regulating ABCA1 in macrophages.