摘要
目的:探讨胰高血糖素样肽-1(GLP-1)受体激动剂exendin-4对内质网应激(ERS)诱导剂衣霉素(TM)介导的3T3-L1脂肪细胞胰岛素抵抗(IR)的影响。方法:体外培养3T3-L1脂肪细胞,分别用TM、内质网应激抑制剂牛磺熊脱氧胆酸(TUDCA)及exendin-4进行干预,以MTT法检测不同干预条件下脂肪细胞的存活情况,以葡萄糖氧化酶法检测不同干预条件下脂肪细胞的葡萄糖消耗量情况,利用Western blot法检测不同干预条件下p-Akt、Akt及ERS关键信号标志蛋白肌醇需求蛋白1(IRE1)、p-IRE1、c-Jun末端激酶(JNK)、p-JNK、蛋白激酶R样内质网激酶(PERK)、p-PERK、真核生物翻译起始因子2的α亚单位(eIF2a)、p-eIF2a和转录激活因子(ATF)-6的蛋白水平。结果:单独TUDCA或exendin-4作用,可协同胰岛素作用,增加胰岛素刺激的脂肪细胞葡萄糖消耗量(P<0.05)。TM(5 mg/L)作用5 h后可减少胰岛素刺激的3T3-L1脂肪细胞萄糖消耗量(P<0.05)及p-Akt的蛋白水平(P<0.05)。TUDCA(1 mmol/L)或exendin-4(100 nmol/L)预处理24 h后,均可拮抗TM对胰岛素刺激的3T3-L1脂肪细胞萄糖消耗量(P<0.05)及p-Akt蛋白水平的改变(P<0.05),二者效价相当。TM(5 mg/L)作用5 h后可显著提高ERS标志蛋白的表达。而exendin-4(100 nmol/L)预处理24 h后,可降低TM诱导的ERS标志蛋白的表达,其效价与应用内质网应激抑制剂TUDCA(1 mmol/L)预处理24 h相当。不同的处理因素对于总IRE1、JNK、PERK及eIF2a的表达情况并无显著性影响。结论:Exendin-4可改善内质网应激介导的3T3-L1脂肪细胞的胰岛素抵抗。
AIM： To explore the effects of exendin-4 （EX-4） on endoplasmic reticulum stress （ERS）-media-ted insulin resistance in the 3T3-L1 adipocytes. METHODS： In vitro 3T3-L1 pre-adipocytes were differentiated into adipo-cytes, and the cells were treated with tunicamycin （TM） , tauroursodeoxycholic acid （TUDCA） or EX4, respectively. The cell viability was measured by MTT assay. The glucose consumption was determined by glucose oxidase assay to evaluate insulin sensitivity of the 3T3-L1 adipocytes with different interventions. The protein levels of p-Akt, Akt and endoplasmic reticulum stress markers, including inositol requiring enzyme-1 （IRE1） , p - IRE1 , JNK, p-JNK, protein kinase R-like en-doplasmic reticulum kinase （PERK） , p-PERK, eukaryotic initation factor2 alpha （eIF2a） , p-eIF2a, activating transcrip-tion factor-6 （ ATF-6 ） were detected by Western blot. RESULTS ： The insulin-stimulated glucose consumption and the pro-tein level of p-Akt were inhibited by TM at 5 mg/L for 5 h （ P 〈 0. 05 ） , while they were increased when the cells were trea-ted with TUDCA at 1 mmol/L or EX-4 at 100 nmol/L for 24 h （ P 〈 0. 05 ） . The effects above induced by TM （ 5 mg/L for 5 h） were also blunted by pretreating with TUDCA at 1 mmol/L or EX^l at 100 nmol/L for 24 h （P 〈0. 05）. The protein levels of ERS markers such as p-IREl, p-JNK, p-PERK, p-eIF2a and ATF-6 were significantly increased by treating with TM at 5 mg/L for 5 h, whereas 24 h pre-treatment with TUDCA or KxA alleviated the ERS of the 3T3-L1 adipocytes in-duced by TM. The expression of total IRE1 , JNK, PERK and eIF2a was not changed in different groups. CONCLU-SION ： Exendin improves endoplasmic reticulum stress mediated insulin resistance in 3T3-L1 adipocytes.
出处
《中国病理生理杂志》
CAS
CSCD
北大核心
2017年第7期1258-1263,共6页
Chinese Journal of Pathophysiology
基金
福建省科技重点项目(No.2013Y0041)
福建省卫生厅青年课题(No.2009-2-24)
国家重点学科老年医学项目资助(No.2015-GJLN-2-04)
福建省卫计委青年项目(No.2014-1-43
No.2015-1-38)
