PPAR δ受体激动剂在肾小管上皮细胞发挥抗炎作用的体外研究

Anti-inflammatory effect of a PPARδ agonist on the renal tubular epithelial cells in vitro

目的研究PPAR δ受体激动剂L165041在肾小管上皮细胞中是否能发挥抗炎作用并探讨其作用机制。方法体外培养小鼠近曲小管上皮细胞(mProx)分为4组:对照组、L165041对照组(10μmol L165041,PPARδ受体激动剂)、棕榈酸钠组(150μmol棕榈酸钠)或TNF-α组(10 nmol TNF-α)和L165041干预组(10μmol L165041预处理3 h后加入150μmol棕榈酸钠或10 nmol TNF-α),作用12 h。用RT-PCR方法检测各组MCP-1 mRNA水平。利用PPARδ干扰RNA(siRNA)转染mProx,以scramble为对照,在转染细胞中重复以上实验。结果与对照组相比,棕榈酸钠和TNF-α刺激使MCP-1 mRNA的表达增强(P<0.05),而L165041下调棕榈酸钠和TNF-α诱导的MCP-1 mRNA表达(P<0.05)。与scramble组相比,转染PPARδsiRNA的肾小管上皮细胞PPAR δ受体在蛋白和mRNA水平表达均明显下降(P<0.05)。在PPARδsiRNA转染细胞中,棕榈酸和TNF-α使MCP-1 mRNA的表达明显增强(P<0.05),L165041仍能显著抑制棕榈酸钠和TNF-α诱导的炎症反应(P<0.05)。另外,与scramble组相比,PPARδsiRNA转染细胞在棕榈酸钠的作用下,使MCP-1表达增强更显著(P<0.05)。结论 PPARδ受体激动剂L165041能抑制小鼠近曲小管上皮细胞的炎症反应,其抗炎作用不依赖于PPARδ受体,而PPARδ受体本身对维持细胞对饱和脂肪酸诱导的炎症反应发挥作用。

【Objective】 To investigate whether L165041, a PPAR δ agonist could exert anti-inflammatory effect in renal tubular epithelial cells and explore the underlying mechanism. 【Methods】 Mouse proximal tubular cells（mProx） cultured in vitro were divided into 4 groups, control group, L165041 control group（10 μmol L165041, a PPAR δ agonist）, palmitate group（150 μmol palmitate） or TNF-α group（10 nmol TNF-α） and L165041 pretreated group（150 μmol palmitate/10 nmol TNF-α, pretreated with 10 uM L165041 for 3 hours）, cells were stimulated for 12 hours, then MCP-1 mRNA expression levels were measured by RT-PCR. mProx were transfected with PPAR δ siRNA, the above procedures were repeated in transfected cells compared with scramble group. 【Results】 Both palmitate and TNF-α stimulation elicited a robust increase in mRNA expression of MCP-1 compared with control group（P〈0.05）. L165041 effectively reversed both palmitate and TNF-α-induced expression of MCP-1（P〈0.05）. Both protein and mRNA expression of PPAR δ in PPAR δ siRNA transfected mProx were effectively decreased compared with scramble group（P〈0.05）. In cells transfected with PPAR δ siRNA, both palmitate and TNF-α stimulation elicited a robust increase in mRNA expression of MCP-1 compared with control group（P〈0.05）. L165041 effectively reversed both palmitate and TNF-α-induced expression of MCP-1（P〈0.05）. In addition, in cells transfected with PPAR δ siRNA, palmitate could elicited more obviously increase in MCP-1 expression compared with scramble group（P〈0.05）. 【Conclusion】PPAR δ agonist L165041 could exert anti-inflammatory effect in cultured mouse proximal tubular cells, while its anti-inflammatory effect is not PPARδ-receptor dependent. PPAR δ receptor itself may play a role in maintaining the cellualr reactivity to saturated fatty acid induced inflammation.