Department of Cardiology, Southwest Hospital, The Third Military Medical University, Chongqing, China.
BMC Biochem. 2013 Aug 3;14:20. doi: 10.1186/1471-2091-14-20.
Studies have shown that inflammation promoted atherosclerotic progression; however, it remains unclear whether inflammation promoted atherosclerotic progression properties by altering cholesterol metabolism in human macrophages. In the present study, we evaluated a potential mechanism of inflammation on atherogenic effects. We evaluated the ability of TNFa to affect Reverse cholesterol transport (RCT) and cholesterol uptake and its mechanism(s) of action in human macrophages.
We initially determined the potential effects of TNFa on cholesterol efflux in the human macrophages. We also determined alterations in mRNA and protein levels of ABCA1, ABCG1, LXRa, CD-36, SR-A in human macrophages using quantitative real-time polymerase chain reaction (PCR) and Western immunoblot analyses. The cholesterol efflux rate and protein expression of ABCA1, ABCG1, LXRa, CD-36, SR-A were quantified in human macrophages under PKC-θ inhibition using PKC-θ siRNA. Our results showed that TNFa inhibited the rate of cholesterol efflux and down-regulation the expression levels of ABCA1, ABCG1 and LXRa and up-regulation the expression levels of CD-36, SR-A in human macrophages; PKC-θ inhibition by PKC-θ siRNA attenuated the effect of TNFa on ABCA1, ABCG1, LXRa, SR-A, CD-36 expression.
Our results suggest TNFa alter cholesterol metabolism in human macrophages through the inhibition of Reverse cholesterol transport and enhancing cholesterol uptake via PKC-θ-dependent pathway, implicating a potential mechanism of inflammation on atherogenic effects.
研究表明炎症促进动脉粥样硬化的进展；然而，目前尚不清楚炎症是否通过改变人巨噬细胞中的胆固醇代谢来促进动脉粥样硬化的进展。在本研究中，我们评估了炎症对动脉粥样硬化作用的潜在机制。我们评估了 TNFa 影响胆固醇逆转运（RCT）和胆固醇摄取的能力及其在人巨噬细胞中的作用机制。
我们首先确定了 TNFa 对人巨噬细胞胆固醇外排的潜在影响。我们还使用定量实时聚合酶链反应（PCR）和 Western 免疫印迹分析确定了人巨噬细胞中 ABCA1、ABCG1、LXRa、CD-36、SR-A 的 mRNA 和蛋白水平的变化。使用 PKC-θ siRNA 抑制 PKC-θ 抑制人巨噬细胞中的胆固醇外排率和 ABCA1、ABCG1、LXRa、CD-36、SR-A 的蛋白表达。我们的结果表明，TNFa 抑制胆固醇外排率，并下调 ABCA1、ABCG1 和 LXRa 的表达水平，上调 CD-36、SR-A 的表达水平在人巨噬细胞中；PKC-θ siRNA 抑制 PKC-θ 减弱了 TNFa 对 ABCA1、ABCG1、LXRa、SR-A、CD-36 表达的影响。
我们的结果表明，TNFa 通过抑制胆固醇逆转运并通过 PKC-θ 依赖性途径增强胆固醇摄取来改变人巨噬细胞中的胆固醇代谢，提示炎症对动脉粥样硬化作用的潜在机制。
