PLIN2通过调控SREBP2促进RAW264.7巨噬细胞脂质蓄积  

PLIN2 promotes lipid accumulation in RAW264.7 macrophages by regu⁃lating SREBP2

作　　者：蒋思怦 张瑞 李晓歌 张荣 郭东铭[1] 袁中华[1] JIANG Si-peng;ZHANG Rui;LI Xiao-ge;ZHANG Rong;GUO Dong-ming;YUAN Zhong-hua(Institute of Cardiovascular Disease,Key Laboratory for Arteriosclerology of Hunan Province,Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic diseases,Hengyang 421001,China)

机构地区：[1]南华大学心血管疾病研究所,动脉硬化学湖南省重点实验室,湖南省动脉硬化性疾病国际科技创新合作基地,湖南衡阳421001

出　　处：《中国病理生理杂志》2021年第1期1-9,共9页Chinese Journal of Pathophysiology

基　　金：国家自然科学基金资助项目(No.81973326)。

摘　　要：目的:探讨脂滴包被蛋白2(PLIN2)是否通过调控固醇调节元件结合蛋白2(SREBP2)影响小鼠RAW264.7巨噬细胞中脂质蓄积。方法:采用氧化低密度脂蛋白(ox-LDL)处理RAW264.7巨噬细胞不同时间(0、6、12、24和48 h),Western blot检测PLIN2和SREBP2蛋白表达水平;过表达或敲减PLIN2,RT-qPCR和Western blot检测SREBP2、3-羟基-3-甲基戊二酰辅酶A还原酶(HMGCR)和葡萄糖调节蛋白78(GRP78)表达水平,油红O染色检测细胞脂质蓄积情况;采用免疫荧光和氧化酶法分别检测PLIN2对SREBP2核转位和细胞内游离胆固醇(FC)的影响;采用内质网应激(ERS)抑制剂4-苯基丁酸(4-PBA)处理细胞,Western blot和RT-qPCR检测GRP78、SREBP2和HMGCR表达水平。结果:ox-LDL处理24 h后,PLIN2和SREBP2表达水平显著增加(P<0.05)。过表达PLIN2能上调SREBP2和HMGCR表达,增加细胞内FC水平(P<0.05),促进细胞内脂质蓄积;敲减PLIN2则相反。此外,过表达PLIN2能增加GRP78表达水平(P<0.05),说明过表达能促进细胞ERS;同时,过表达PLIN2能激活SREBP2并促进其核转位;ERS抑制剂4-PBA可显著抑制SREBP2及HMGCR蛋白表达水平的上升(P<0.05)。结论:PLIN2通过上调SREBP2表达,从而促进RAW264.7巨噬细胞脂质蓄积。AIM:To investigate whether perilipin 2(PLIN2)promotes lipid accumulation by regulating the expression of sterol regulatory element binding protein 2(SREBP2)in mouse RAW264.7 macrophages.METHODS:Oxidized low-density lipoprotein(ox-LDL)was used to treat RAW264.7 macrophages for different time(0,6,12,24 and 48 h),and Western blot was used to detect the protein levels of PLIN2 and SREBP2.The expression levels of SREBP2,3-hydroxy-3-methylglutaryl-coenzyme A reductase(HMGCR)and glucose-regulated protein 78(GRP78)were detected by RT-qPCR and Western blot in RAW264.7 macrophages withPLIN2 over-expression or knock-down,and lipid accumulation in the cells was observed by oil red O staining.The effects of PLIN2 on SREBP2 nuclear translocation and intracellular free cholesterol(FC)were detected by immunofluorescence and oxidase methods,respectively.The RAW264.7 cells were treated with endoplasmic reticulum stress(ERS)inhibitor 4-phenylbutyric acid(4-PBA)for 2 h,and the expression levels of GRP78,SREBP2 and HMGCR were detected by RT-qPCR and Western blot.RESULTS:Pretreatment with oxLDL at 50 mg/L for 24 h significantly increased the protein levels of PLIN2 and SREBP2.Over-expression of PLIN2 upregulated the expression of SREBP2 and HMGCR,and increased the FC content and lipid accumulation in the cells,while knock-down ofPLIN2 had an opposite result.In addition,the protein level of GRP78 was decreased,and the nuclear translocation of SREBP2 was increased in the cells with PLIN2 over-expression.Treatment with ERS inhibitor 4-PBA for 2 h significantly decreased the protein levels of SREBP2 and HMGCR in the cells.CONCLUSION:PLIN2 promotes lipid accumulation in RAW264.7 macrophages by up-regulating SREBP2 signaling.

关 键 词：脂滴包被蛋白2 内质网应激 固醇调节元件结合蛋白2 3-羟基-3-甲基戊二酰辅酶A还原酶 葡萄糖调节蛋白78 

分 类 号：R363.2[医药卫生—病理学] R543.5[医药卫生—基础医学]