CD163/TWEAK通路对动脉粥样硬化的作用

Role of CD163/TWEAK pathway in atherosclerosis

目的:探讨CD163/肿瘤坏死因子样凋亡弱诱导因子(TWEAK)途径对小鼠动脉粥样硬化的影响。方法:以8～10周的载脂蛋白E基因敲除(APOE^(-/-))及野生型(WT)C57BL/6小鼠为研究对象,分为以下4组(n=10):APOE^(-/-)+普食(ND)组、APOE^(-/-)+高脂饮食(WD)组、WT+ND组和WT+WD组。喂养16周后检测血脂水平,主动脉油红O染色测定主动脉斑块面积以明确成功建立动脉粥样硬化模型;Western blot法检测各组小鼠主动脉CD163和TWEAK的蛋白表达水平;免疫组化法明确动脉粥样硬化斑块CD163与TWEAK的表达及空间分布特征;细胞实验研究CD163对1型巨噬细胞(M1)及泡沫细胞TWEAK的调节作用及其可能的下游作用途径。结果:血脂检测及主动脉油红O染色结果显示,APOE^(-/-)+ND及APOE^(-/-)+WD组小鼠成功建立动脉粥样硬化模型。免疫组化可见CD163主要表达于远离脂质核心的部位,而TWEAK可见于动脉粥样硬化斑块的所有部位。主动脉Western blot检测结果显示,与WT小鼠相比,APOE^(-/-)小鼠主动脉CD163的表达水平显著增加(P<0.05),与之相对应的是APOE^(-/-)小鼠主动脉中TWEAK表达水平较WT小鼠亦显著升高(P<0.05)。细胞实验结果显示CD163可显著抑制TWEAK的蛋白表达,明显下调核因子κB(NF-κB)的水平(P<0.05)。结论:CD163可通过抑制TWEAK/NF-κB途径而发挥抗动脉粥样硬化作用。

AIM: To investigate the effect of CD163/tumor necrosis factor-like weak inducer of apoptosis(TWEAK) pathway on atherosclerosis in mice. METHODS: APOE^-/-mice and wild-type(WT) C57 BL/6 mice were divided into 4 groups(8~10 weeks, n=10): APOE^-/-+normal diet(ND) group, APOE^-/-+western diet(WD) group, WT+ND group, and WT+WD group. Detection of blood lipid levels and oil red O staining of aorta artery were performed to confirm whether the atherosclerotic model was well established in 16 weeks after feeding. The aortic tissues were harvested to measure CD163 and TWEAK protein levels by Western blot, and immunohistochemical staining was also performed to localize CD163 and TWEAK protein expression on atherosclerotic plaque in each group. The cell experiments were conducted to study whether CD163 regulated TWEAK expression in M1 macrophages and foam cells, and the possible downstream pathway was investigated. RESULTS: The blood lipid levels and aorta oil red O staining showed that the animal model of atherosclerosis was successfully established in APOE^-/-+ND group and APOE^-/-+WD group. The protein level of CD163 was significantly increased in the aortic tissue in APOE^-/-mice(P<0.05) as compared with C57 BL/6 mice(P<0.05). Consistently, the protein level of TWEAK was also markedly higher in APOE^-/-+ND group and APOE^-/-+WD group than that in WT+ND group and WT+WD group(P<0.05). Immunohistochemical staining showed that CD163 was mainly expressed in the parts away from the lipid core, and TWEAK was found in all parts of the atherosclerotic plaque. CD163 significantly inhibited the protein expression of TEWAK in the M1 macrophages, and also significantly down-regulated the level of nuclear factor-κΒ(NF-κB) in the M1 macrophages and foam cells(P<0.05). CONCLUSION: The protein levels of CD163 and its ligand TWEAK are significantly increased in atherosclerotic mice. The CD163 positive macrophages are mainly located at the site far away from the lipid core, and CD163 may play an anti-atherosclerotic effect by inhibiting TWEAK/NF-κB pathway.