PPARγ激动剂通过Akt信号转导通路抑制HIV-1Tat诱导的血管炎性反应

摘要

Objective To evaluate the protection effect of peroxisome proliferator‐activated receptor gamma (PPARγ) against HIV‐1 Tat‐induced responses of adhesion molecules in brain microvascular endothelial cells and the possible signaling mechanism .Methods The protein expressions or mRNA levels of intercellular adhesion molecule‐1 ( ICAM‐1 ) and vascular cell adhesion molecule‐1 ( VCAM‐1 ) in human cerebral microvascular endothelial cells (hCMEC/D3 ) were assessed by Western blot or Real‐time‐PCR , with the exposure of HIV‐1 Tat , rosiglitazone (PPARγ agonist) , GW9662 (PPARγ antagonist) and/or KP3721 (Akt inhibitor) .Results HIV‐1 Tat induced upregulation of the protein expression of ICAM‐1 (P< 0.05) ,VCAM‐1 (P< 0.01) in hCMEC/D3 as well as mRNA levels ( P < 0.01 , respectively ) . Exposure to PPARγ agonist rosiglitazone decreased Tat‐induced protein expression of ICAM‐1 (P < 0.05) ,ICAM‐1 mRNA and VCAM‐1 mRNA levels (P < 0.01 , respectively ) . This inhibition was abolished by the addition of PPARγ antagonist GW9662 (P< 0.01 ,respectively) and Akt inhibitor KP3721 (P< 0.01 ,respectively) .Treatment of hCMEC/D3 with rosiglitazone dramatically inhibited the HIV‐1 Tat‐induced inflammatory activation of Akt phosphorylation (P < 0.01 ) .Conclusions PPARγ may inhibit HIV‐1 Tat‐induced responses of adhesion molecules in brain microvascular endothelial cells. Akt signaling pathway plays a key role on the protection effect of PPARγ agonist on vascular inflammatory response that contributes to the destruction of blood brain barrier .%目的：探讨过氧化物酶体增殖物激活受体γ（peroxisome proliferator‐activated receptor gamma ， PPARγ）对人类免疫缺陷病毒‐1型反式转录激活因子（HIV‐1 transactivator of transcription ，HIV‐1 Tat）诱导的脑微血管内皮细胞中黏附分子反应的影响及其作用机制。方法将培养的人脑微血管内皮细胞（human cere‐bral microvascular endothelial cells ，hCMEC／D3）给予 HIV‐1 Tat 、PPARγ激动剂罗格列酮、PPARγ拮抗剂GW9662、蛋白激酶 B（Akt）抑制剂 KP3721进行干预，并设立对照组。分别以蛋白免疫印迹法和实时反转录聚合酶链式反应检测 hCMEC／D3中细胞间黏附分子‐1（intercellular adhesion molecule‐1，ICAM‐1）、血管细胞黏附分子‐1（vascular cell adhesion molecule‐1，VCAM‐1）蛋白和 mRNA 表达。结果 HIV‐1 Tat 可诱导黏附分子ICAM‐1和 VCAM‐1的蛋白（P＜0.05，P＜0.01）及其 mRNA 表达增加（均 P＜0.01），PPARγ激动剂罗格列酮可抑制 HIV‐1 Tat 诱导的 ICAM‐1蛋白（P＜0.05）与 mRNA 以及 VCAM‐1的 mRNA 表达（均 P＜0.01），而这种抑制作用可被 PPARγ拮抗剂 GW9662和 Akt 抑制剂 KP3721逆转（均 P ＜0.01）。罗格列酮可抑制 HIV‐1 Tat 诱导的 Akt 磷酸化反应（P＜0.01）。结论 PPARγ可抑制 HIV‐1 Tat 诱导的脑微血管内皮细胞中黏附分子反应，Akt 信号转导通路在 PPARγ激动剂抑制血管内皮细胞炎性反应中起到重要的作用。