Rubic Tina, Lorenz Reinhard L
Institute for Prophylaxis of Cardiovascular Diseases, University of Munich, Germany, Pettenkoferstrasse 9, D-80336 Munich, Germany.
Cardiovasc Res. 2006 Feb 1;69(2):527-35. doi: 10.1016/j.cardiores.2005.10.018. Epub 2005 Dec 5.
Marked anti-atheromatous effects of the anti-inflammatory cytokine interleukin-10 (IL-10) were observed in several lipid-driven animal models of arteriosclerosis. We therefore investigated whether IL-10 affects macrophage cholesterol handling.
Human THP-1 cells and peripheral monocytes served as macrophage models. Specific mRNA was quantified by real-time RT-PCR, protein expression by flow cytometry and Western blotting. Cellular cholesterol handling was studied by lipoprotein-facilitated uptake and efflux assays. IL-10 effects were also studied in cells transfected with liver X receptor alpha (LXRalpha)-siRNA or a LXRalpha response element (LXRE) reporter construct.
Picomolar IL-10 suppressed basal and peroxisome proliferator-activated receptor gamma (PPARgamma)-stimulated transcription of the scavenger receptor CD36 due to reduced PPARgamma protein expression. In contrast, IL-10 stimulated transcription of the active cellular cholesterol exporters ATP-binding cassette transporters A1 and G1 (ABCA1, ABCG1) and the LDL receptor, whereas scavenger receptor-BI (SR-BI) was unchanged. The reduction of CD36 and stimulation of ABCA1 expression was confirmed in human monocytes. Thereby, IL-10 prevented cellular cholesterol overloading from oxidized LDL (oxLDL) and enhanced efflux to apoA-containing particles initiating reverse cholesterol transport. Experiments with inhibitors, LXRalpha silencing and the LXRE reporter gene construct supported the proximal transmission of the IL-10 effect on ABCA1 by the IL-10 receptor/signal transducer and activator of transcription 3 (STAT3) pathway and distal cross-talk to the LXRalpha and PPARalpha/retinoic acid X receptor (RXR) and cAMP/protein kinase A (PKA) pathways.
In addition to immune and anti-inflammatory actions, IL-10 redirects macrophage cholesterol handling towards reverse cholesterol transport, which contributes to its anti-atherosclerotic action.
在几种脂质驱动的动脉粥样硬化动物模型中观察到抗炎细胞因子白细胞介素-10（IL-10）具有显著的抗动脉粥样硬化作用。因此，我们研究了IL-10是否影响巨噬细胞胆固醇处理。
人THP-1细胞和外周血单核细胞作为巨噬细胞模型。通过实时逆转录聚合酶链反应（RT-PCR）定量特异性mRNA，通过流式细胞术和蛋白质印迹法检测蛋白质表达。通过脂蛋白促进的摄取和流出试验研究细胞胆固醇处理。还在转染了肝脏X受体α（LXRα）小干扰RNA（siRNA）或LXRα反应元件（LXRE）报告基因构建体的细胞中研究了IL-10的作用。
皮摩尔浓度的IL-10由于PPARγ蛋白表达降低，抑制了清道夫受体CD36的基础转录以及过氧化物酶体增殖物激活受体γ（PPARγ）刺激的转录。相反，IL-10刺激活性细胞胆固醇转运蛋白ATP结合盒转运体A1和G1（ABCA1、ABCG1）以及低密度脂蛋白受体的转录，而清道夫受体-BI（SR-BI）则无变化。在人单核细胞中证实了CD36的减少和ABCA1表达的增加。由此，IL-10可防止细胞因氧化型低密度脂蛋白（oxLDL）导致胆固醇过载，并增强向含载脂蛋白A颗粒的流出，从而启动逆向胆固醇转运。使用抑制剂、LXRα沉默和LXRE报告基因构建体进行的实验支持了IL-10通过IL-10受体/信号转导及转录激活因子3（STAT3）途径对ABCA1产生的近端效应，以及与LXRα和PPARα/视黄酸X受体（RXR）和环磷酸腺苷/蛋白激酶A（PKA）途径的远端相互作用。
除免疫和抗炎作用外，IL-10还将巨噬细胞胆固醇处理导向逆向胆固醇转运，这有助于其抗动脉粥样硬化作用。
