Sun Haige, Shen Jiangang, Liu Tingrong, Tan Ying, Tian Di, Luo Tiantian, Lai Wenyan, Dai Meng, Guo Zhigang
Division of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, PR China.
School of Chinese Medicine, The University of Hong Kong, 10 Sassoon Road, Hong Kong.
Atherosclerosis. 2014 Dec;237(2):853-61. doi: 10.1016/j.atherosclerosis.2014.10.012. Epub 2014 Oct 31.
To explicit whether the functions of high density lipoprotein (HDL) are impaired in murine atherosclerosis by subcutaneous immunization with recombinant mycobacterial heat shock protein 65 (HSP65).
C57BL/6 mice were fed a normal chow-diet with non immunization as normal group. ApoE knockout (ApoE(-/-)) mice on high-fat diet were randomly divided into three groups (n = 8) and immunized subcutaneously with different concentrations of HSP65 or phosphate-buffered saline (PBS). All animals were treated for 16 weeks. Reverse cholesterol efflux, the anti-oxidant and anti-inflammatory functions of HDL were assayed. Hepatocytes and peritoneal macrophages were isolated to examine the expression of cholesterol transport regulating proteins, including SR-B1, ABCA1, ABCG1, PPAR-γ and LXR-α.
In HSP65-immunized mice, paraoxonase1 (PON1) activity and the expression of IL-10 were reduced, while High-density lipoprotein inflammatory index (HII), myeloperoxidase (MPO) activity, and the expression of IFN-γ were elevated gradually. The MPO/PON1 ratio amount was significantly higher in HSP65-immunized group than in normal or PBS-immunized group. In addition, compared with normal or PBS-immunized group, cholesterol efflux rate and the expression of regulating proteins were markedly decreased in HSP65-immunized group. The mice immunized with HSP65 developed significantly larger aorta atherosclerotic plaques when compared with PBS-treated littermates. The high MPO/PON1 ratio was correlated with HII, cholesterol efflux rate and atherosclerotic plaques.
This study demonstrates that subcutaneous immunization with HSP65 impairs the properties of HDL, which may contribute to its important pathogenic role of HSP65 in atherogenesis. Also, MPO/PON1 ratio may be a predictor of AS.
通过皮下注射重组分枝杆菌热休克蛋白65（HSP65），明确高密度脂蛋白（HDL）功能在小鼠动脉粥样硬化中是否受损。
C57BL/6小鼠喂食普通饲料且不进行免疫作为正常组。高脂饮食的载脂蛋白E基因敲除（ApoE(-/-)）小鼠随机分为三组（n = 8），分别皮下注射不同浓度的HSP65或磷酸盐缓冲液（PBS）。所有动物均接受16周治疗。检测HDL的胆固醇逆向转运、抗氧化和抗炎功能。分离肝细胞和腹腔巨噬细胞，检测胆固醇转运调节蛋白包括SR-B1、ABCA1、ABCG1、PPAR-γ和LXR-α的表达。
在HSP65免疫的小鼠中，对氧磷酶1（PON1）活性和白细胞介素10（IL-10）表达降低，而高密度脂蛋白炎症指数（HII）、髓过氧化物酶（MPO）活性和干扰素-γ（IFN-γ）表达逐渐升高。HSP65免疫组的MPO/PON1比值显著高于正常组或PBS免疫组。此外，与正常组或PBS免疫组相比，HSP65免疫组的胆固醇流出率和调节蛋白表达明显降低。与PBS处理的同窝小鼠相比，HSP65免疫的小鼠主动脉粥样硬化斑块明显更大。高MPO/PON1比值与HII、胆固醇流出率和动脉粥样硬化斑块相关。
本研究表明，皮下注射HSP65会损害HDL的特性，这可能是HSP65在动脉粥样硬化发生中重要致病作用的原因。此外，MPO/PON1比值可能是动脉粥样硬化的一个预测指标。
