LXRs/ABCA1调控视网膜色素上皮细胞炎症反应改善脂质过氧化引起的凋亡反应

LXRs/ABCA1 inhibits the apoptotic response induced by lipid peroxidation by reducing the inflammatory response of retinal pigment epithelial cells

目的探讨肝X受体(LXRs)对视网膜色素上皮细胞(RPE)脂质过氧化所致凋亡的调控作用。方法实验研究。体外培养ARPE-19细胞,分为4组,control、DMSO、7 kCh(7-ketocholesterol,7 kCh)、GW3965组;油红O染色、7 kCh免疫荧光染色检测各组ARPE-19细胞脂质堆积。siRNA转染ARPE-19细胞,然后7 kCh(20μM)处理24 h,RT-PCR检测LXRs、ABCA1、IL-1β、Caspase1的表达。Annexin-V/PI染色检测各组细胞凋亡。结果GW3965组ARPE-19细胞内脂滴及7 kCh减少,LXRα、LXRβ(P<0.001)、ABCA1表达(P<0.0001)在mRNA水平上上调。siRNA转染敲低LXRα、LXRβ,发现敲低LXRβ后ARPE-19细胞内IL-1β、Caspase1mRNA表达水平上调,晚期凋亡细胞增加;而敲低LXRα使早期凋亡细胞增多。结论激活LXRs/ABCA1通路可能减轻RPE的炎症反应,从而改善了因视网膜脂质过氧化导致的RPE凋亡。

Objective To investigate the regulation of liver X receptor(LXRs)on apoptosis induced by lipid peroxidation in retinal pigment epithelial cells(RPE).Methods Experimental study.ARPE-19 cells were cultured in vitro and divided into 4 groups:the control,DMSO,7 kCh(7-ketocholesterol,7 kCh)and GW3965 group.Lipid accumulation of ARPE-19 cells was detected by oil red O staining and 7 kCh immunofluorescence staining.ARPE-19 cells were transfected with siRNA,and then the expressions of LXRs,ABCA1,IL-1βand Caspase1 was detected by RT-PCR after treated with 7 kCh(20μM)for 24 h.Annexin V/PI staining was used to detect the apoptosis.Results In the GW3965 group,lipid droplets and 7 kCh in ARPE-19 cells were decreased,and the expression of LXRα,LXRβ(P<0.001)and ABCA1(P<0.0001)were up-regulated at mRNA levels.After LXRαand LXRβwere knocked down by siRNA transfection,the expression levels of IL-1βand Caspase1mRNA in ARPE-19 cells were up-regulated,and the apoptotic cells in late stage increased.The knockdown of LXRαincreased the number of early apoptotic cells.Conclusions Activation of the LXRs/ABCA1 pathway may reduce the inflammatory response of RPE,thereby ameliorating the apoptosis of RPE caused by retinal lipid peroxidation.