替米沙坦改善小胶质细胞炎症与其促进激活表型转化有关

Ameliorative effect of telmisartan on inflammatory reaction in microglia related to promoting activated microglia phenotype transformation

目的：研究替米沙坦改善脂多糖（lipopolysaccharide，LPS）诱导的小胶质细胞炎症反应是否与其激活过氧化物酶体增殖物激活受体γ（peroxisome proliferator-activated receptor γ，PPARγ）进而促进小胶质细胞激活表型转化有关。方法采用荧光素酶报告基因检测方法研究替米沙坦对PPARγ的激动活性；建立LPS诱导的小鼠BV-2小胶质细胞炎症模型，在该模型上用0.1~10 mol/L替米沙坦单独处理BV-2细胞，或者1μmol/L替米沙坦与10μmol/L PPARγ特异性阻断剂GW9662共同处理BV-2细胞，用ELISA法检测细胞上清中肿瘤坏死因子-α（tumor necrosis factor-alpha，TNF-α）的含量，用实时定量PCR法检测BV-2小胶质细胞M1型细胞标志物（CD16、CD11b、iNOS）和M2型细胞标记物IL-10的mRNA表达水平变化。结果与溶剂对照组相比，0.1~10 mol/L替米沙坦能浓度依赖地激活PPARγ，对荧光素酶的诱导倍数分别为1.29、1.36和1.45（均P＆lt;0.01）；在LPS诱导的BV-2小胶质细胞炎症模型上，与溶剂对照组相比，LPS处理组细胞上清中TNF-α的含量显著升高（P＆lt;0.01），小胶质细胞M1型标记物CD16、CD11b和iNOS mRNA表达水平显著上调（P＆lt;0.05）；与LPS处理组相比，0.1~10 mol/L替米沙坦能浓度依赖地降低小胶质细胞上清中TNF-α的含量（P＆lt;0.05），10 mol/L替米沙坦能显著下调小胶质细胞M1型标记物CD16、CD11b和iNOS 的mRNA表达水平（P＆lt;0.01和P＆lt;0.05），且0.1 mol/L替米沙坦能显著上调小胶质细胞M2型标记物IL-10的mRNA表达水平（P＆lt;0.05）；与1 mol/L替米沙坦处理组相比，PPARγ特异性阻断剂GW9662能显著上调CD16的mRNA表达水平（P＆lt;0.05）。结论替米沙坦显著抑制LPS诱导的小胶质细胞激活后TNF-α的释放，其作用机制可能与替米沙坦激活PPARγ并促进小胶质细胞M1/M2激活表型的转化密切相关。

Objective To evaluate the ameliorative effect of telmisartan on the inflammatory reaction induced by lipopolysaccharide（LPS） in microglia cells and investigate its effect on modulation of activated microglia phenotype transformation by activation of the peroxisome proliferator-activated receptor γ （PPARγ） accordingly. Methods The PPARγ agonistic activity of telmisartan was explored using PPARγ-responsive element- lucifarase reporter assay ,and inflammatory model was established through LPS-induced microglia cells. The mice microglia cells （BV-2 microglia cell line） were treated in the presence of telmisartan ranging from 0.1 to 10 μmol/L or in the presence of 1 mol/L telmisartan with 10 μmol/L GW9662, the specific PPARγ antagonist. The contents of tumor necrosis factor-alpha （TNF-α ） in cell supernatants were analyzed by ELISA; the mRNA expression level of M1 phenotype markers CD16, CD11b and iNOS as well as M2 phenotype marker IL-10 were evaluated using the real-time quantitative PCR. Results Compared with control group, telmisartan could concentration-dependently activate the PPARγ ranging from 0.1 to 10 μmol/L and the relative lucifarase activity induced by telmisartan was 1.29, 1.36 and 1.45 folds （P＆lt;0.01）, respectively; in the inflammatory model of BV-2 cells induced by LPS, compared with control group, the content of TNF-α in cell supernatants significantly increased （P＆lt;0.01） and the mRNA expression level of M1 phenotype microglia markers CD16, CD11b and iNOS was significantly up-regulated （P＆lt;0.05） in LPS group; compared with LPS group, telmisartan could concentration-dependently decreased the content of TNF-α in cell supernatants arranging from 0.1 to 10 mol/L （P＆lt;0.05）; 10 mol/L telmisartan could significantly down-regulated the mRNA expression level of M1 phenotype microglia markers CD16, CD11b and iNOS （P＆lt;0.01, P＆lt;0.05 and P＆lt;0.05） ; additionally, 0.1 μmol/L telmisartan could significantly up-regulated the mRNA expression level of M2 phenotype microglia marker IL-10 （P＆lt;0.05）; compared with 1 mol/L telmisartan treated group, the mRNA expression level of CD16 was significantly up-regulated by specific PPARγ antagonist GW9662 （P＆lt;0.05）. Conclusion Telmisartan could markedly reduce the release of TNF-α in LPS-induced activated microglia cells; the mechanism is associated with modulating the transformation of M1/M2 microglia phenotype by the activation of PPARγ.