PNPLA3对棕榈酸引起的肝细胞凋亡的影响  

The influence of patatin-like phospholipase domain-containing protein 3 on palmitic acid-induced hepatocyte apoptosis

作　　者：袁淑华[1] 梁华[1] 蔡梦茵[1] 徐芬[1] 袁丁[1] 郑晓彬[1] 李麦心悦 翁建平[1] 

机构地区：[1]中山大学附属第三医院内分泌与代谢病学科广东省糖尿病防治重点实验室,广州510630

出　　处：《中华医学杂志》2016年第19期1535-1539,共5页National Medical Journal of China

基　　金：国家自然科学基金（81370909）

摘　　要：目的研究含patatin样磷脂酶域3（PNPLA3）对棕榈酸（PA）引起的肝细胞凋亡的影响及相关机制。方法以人肝癌细胞株HepG2为研究对象，分为过表达空载体（NC）组，过表达野生型PNPLA3（PNPLA3 WT）组以及过表达突变型PNPLA3（PNPLA3 I148M）组，PA处理24h，油红染色检测细胞内脂质沉积，原位缺口末端标记法（TUNEL）检测细胞凋亡，蛋白印迹法检测内质网应激及相关凋亡蛋白水平；酶联免疫吸附法（ELISA）检测细胞上清溶血卵磷脂（LPC）水平。结果PA处理24h后，3组细胞脂肪沉积差异无统计学意义（P〉0．05）。与NC组相比，PNPLA3 WT和PNPLA3 I148M 组细胞凋亡率分别增加了2倍和3倍。内质网应激相关的蛋白激酶R样内质网激酶（PERK）通路激活，免疫球蛋白结合蛋白（BIP）、p-PERK、p-eIF2α蛋白表达增加，内质网应激凋亡通路CCAAT增强子结合蛋白（CHOP）、线粒体凋亡通路相关蛋白p53上调凋亡因子（PUMA）、Bax、caspase-3表达增加，且PNPLA3 I148M组增加更明显。PNPLA3wT和PNPLA3 I148M组在PA干预前后细胞上清LPC水平分约别为NC组的5倍和1．5倍。结论PNPLA3可能通过调节LPC的代谢继而激活内质网应激相关凋亡途径参与PA诱导的肝细胞凋亡。Objective To explore the influence of patatin-like phospholipase domain-containing protein 3 （PNPLA3） on palmitie acid （PA）-induced hepatoeyte apoptosis and its mechanism. Methods Human hepatoearcinoma cell line HepG2 cells were transfeeted with PNPLA3WT-peDNA3.1 （ PNPLA3wT group） and PNPLA3IlgSM-pcDNA3.1 （PNPLA3n4sM group） plasmids respectively to overexpress wild type or mutant type PNPLA3, and cells transfected with empty vector peDNA3.1 （NC group） were set as control group. After 24 h PA incubation, Oil red staining was used to determine lipid deposition, and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay （TUNEL） was used to measure apoptosis. Western blot was used to detect the protein level of endoplasmic reticulum （ ER ） stress and associated apoptosis. Enzyme-linked immunosorbent assay （ ELISA ） was used to test lysolecithin （ LPC ） levels in the cellular supematant. Results After 24 h PA incubation, there was no significant difference in lipid deposition among three groups. Compared to NC group, the cell apoptosis rates of PNPLA 3 WT and PNPLA3 I148M groups were increased by 2 times and 3 times respectively. The levels of ER stress PRKR-like endoplasmic reticulum kinase （PERK） pathway associated proteins, immunoglobulin-binding protein （BIP）, p-PERK, p-eIF2α, and ER stress associated apoptosis pathway proteins, CCAAT/enhancer binding homologous protein （ CHOP）, 1：63 upregulated modulator of apoptosis （ PUMA）, Bax, easpase-3 were higher, and were more significant in PNPLA3 I148M group. The LPC level in the supematant of PNPLA3 WT and PNPLA3 I148M groups were about 5 times and 1.5 times of NC group respectively after PA incubation. Conclusion PNPLA3 may be involved in palmitic acid-induced apoptosis mediated by hepatocyte ER stress through regulating LPC metabolism.

关 键 词：非酒精性脂肪肝 PNPLA3 溶血磷脂酰胆碱 棕榈酸 细胞凋亡 

分 类 号：R575[医药卫生—消化系统]