摘要
目的探讨艾塞那肽(Exendin-4)对棕榈酸(PA)诱导的脂毒性保护效应是否通过胰岛βTc6细胞Toll样受体4(TLR4)/c-Jun氨基末端激酶(JNK)/Bcl-2相关X蛋白(Bax)通路发挥作用。方法(1)构建βTc6细胞脂毒性模型,观察胰岛素分泌水平和TLR4、p-JNK、JNK、Bax、Bcl-2蛋白表达情况;(2)分别予TLR4阻滞剂(CLI-095)、JNK阻滞剂(SP600125)干预,将细胞分对照组、PA组、CLI-095组、SP600125组、PA+CLI-095组和PA+SP600125组,观察胰岛素分泌水平和Bax、Bcl-2蛋白表达情况;(3)使用Exendin-4,将细胞分为对照组、PA组、Exendin-4组和Exendin-4+PA组,观察胰岛素分泌水平和TLR4、p-JNK、JNK、Bax、Bcl-2蛋白表达情况;(4)使用TLR4激动剂(LPS)或阻滞剂、JNK激动剂(anisomycin)或阻滞剂观察对Exendin-4的脂毒性干预作用,分为对照组、CLI-095组、SP600125组、LPS组、anisomycin组、Exendin-4+PA组、CLI-095+Exendin-4+PA组、SP600125+Exendin-4+PA组、LPS+Exendin-4+PA组、anisomycin+Exendin-4+PA组观察βTC6细胞的胰岛素分泌水平。结果(1)与对照组比较,PA可下调葡萄糖刺激的胰岛素分泌(GSIS)(P<0.05),上调TLR4、p-JNK蛋白表达(P<0.05),下调Bcl-2/Bax(P<0.05);(2)PA诱导的脂毒性损害在应用CLI-095或SP600125后,GSIS改善(P<0.05),Bcl-2/Bax升高(P<0.05);(3)Exendin-4干预后,GSIS改善(P<0.05),TLR4、p-JNK蛋白表达下调(P<0.05),Bcl-2/Bax上调(P<0.05);抑制TLR4或JNK活性可增强Exendin-4改善脂毒性β细胞胰岛素分泌功能的作用,反之增加TLR4或JNK活性则可拮抗Exendin-4对胰岛素分泌的改善作用。结论PA引起胰岛β细胞功能障碍可能与TLR4/JNK/Bax通路有关,Exendin-4对PA的上述作用具有部分拮抗作用。
Objective To explore whether the protective effect of Exendin-4 on lipotoxicity induced by palmitic acid(PA)was mediated by toll-like receptor 4(TLR4)/c-Jun amino-terminal kinase(JNK)/Bcl-2 associated X protein(Bax)pathway inβTC6 cells.Methods The lipotoxic model ofβTc6 was established,insulin secretion and protein expression of TLR4,p-JNK,JNK,Bax and Bcl-2 were detected.(2)TLR4 inhibitor(CLI-095)and JNK inhibitor(SP600125)were added and cells were divided into control group,PA group,CLI-095 group,SP600125 group,PA+CLI-095 group and PA+SP600125 group.Insulin secretion and protein expression of Bax and Bcl-2 were observed.(3)Cells were divided into control group,PA group,Exendin-4 group and Exendin-4+PA group.Insulin secretion and protein expression of TLR4,p-JNK,JNK,Bax and Bcl-2 were detected.(4)The protective effect of Exendin-4 on lipotoxicity was observed using TLR4 agonist(LPS)or inhibitor,JNK agonist(anisomycin)or inhibitor.Cells were divided into control group,CLI-095 group,SP600125 group,LPS group,anisomycin group,Exendin-4+PA group,CLI-095+Exendin-4+PA group,SP600125+Exendin-4+PA group,LPS+Exendin-4+PA group,anisomycin+Exendin-4+PA group and insulin secretion ofβTC6 cells was observed.Results(1)Compared with the control group,PA down-regulated glucose-stimulated insulin secretion(GSIS)(P<0.05),up-regulated TLR4 and p-JNK expression level(P<0.05)and down-regulated the Bcl-2/Bax ratio(P<0.05).(2)CLI-095 or SP600125 improved GSIS(P<0.05)and ratio of Bcl-2/Bax against lipotoxicity induced by PA(P<0.05).(3)Exendin-4 also increased GSIS(P<0.05),decreased the expression of TLR4 and p-JNK(P<0.05)and increased ratio of Bcl-2/Bax(P<0.05).Inhibiting the activity of TLR4 or JNK can enhance the effect of Exendin-4 on improving the insulin secretion ofβ-cells which induced by lipotoxicity,while increasing the activity of TLR4 or JNK antagonizes the effect of Exendin-4 on improving insulin secretion.Conclusions PA may induce the dysfunction ofβcell through TLR4/JNK/Bax signal pathway and Exendin-4 could partly pro
作者
江震
沈喜妹
杨立勇
JIANG Zhen;SHEN Ximei;YANG Liyong(Department of Endocrinology,The First Affiliated Hospital of Fujian Medical University,Fujian Province Clinical Research Center for Metabolic Diseases,Diabetes Research Institute of Fujian Province,Metabolic Diseases Research Institute,Fujian Medical University,Fuzhou 350005,China)
出处
《福建医科大学学报》
2021年第5期367-372,共6页
Journal of Fujian Medical University
基金
国家自然科学基金项目(81870572)。
