The expression of Toll-like receptor 4 in renal tubular epithelia cells stimulated by Angiotensin II

Abstract

Objective To obese the change of Toll like Receptor 4(TLR4)in renal tubular epithelia cells(NRK-52E)stimulated by angiotensin Ⅱ(AngⅡ),and study the mechanisms of TLR4 in hypertensive renal injury.Methods NRK-52E were incubated with different concentrations of Angll(10-6～10-12M),the optimal concentration of AngⅡ was selected to incubated NRK-52E for 6～48h to choose the best cultivate time.TLR4 RNA interference(RNAi)plasmids were stably transfeeted into NRK-52E.The TLR4 mRNA and protein expressions were detected by Reverse transcription-polymeric chain reaction(RT-PCR)and Western Blotting.The IL-6 and TNF-α supernatant levels were also tested by enzyme linked immunosorbent-assay(ELISA).Results AnglI(10-6～10-9M)can obviously up-regulated TLR4 mRNA(P＜0.05),TLR mRNA increased after induced by AnglI for 6h,and the peak can maintain for 12～24h(P＜0.05).The cell supernatant excretive levels of IL-6 and TNF-α obviously increased when stimulated by 10-7 M AngⅡ for 24h(P＜0.01).TLR4 RNAi plasmids(Si525 and Si526)can obviously inhibited TLR mRNA and protein expression(P＜0.01 or P＜0.05),the silence efficiency of Si526 is better than Si525(P＜0.05).After stimulated by 10-7 M AngⅡ for 24h,supematant excretive levels of IL-6,TNF.ot in NRK-52E which stably transfected Si526 were notably decreased contrasted to the levels that stimulated the normal NRK-52E(P＜0.05).Conclusions AngⅡ can up-regulated the expressions of TLR4,IL-6 and TNF-α in NRK-52E.TLR4 RNAi can depressed the related inflammation factors when stimulated with AngⅡ,which indicate TLR4 may has correlative relationship with inflammatory factors.Thus.it may be one of the mechanisms of inflammatory reaction that induced to hypertensive renal injury. Key words: Receptors,cell surface; Angiotensin Ⅱ; Kidney tubules; Epithelium