Department of Pediatrics Ehime University Graduate School of Medicine Ehime Japan.
Department of Diabetes and Molecular Genetics Ehime University Graduate School of Medicine Ehime Japan.
J Diabetes Investig. 2016 May;7(3):312-23. doi: 10.1111/jdi.12434. Epub 2015 Nov 18.
AIMS/INTRODUCTION: Resistin, secreted from adipocytes, causes insulin resistance in mice. In humans, the resistin gene is mainly expressed in monocytes and macrophages. Tunicamycin is known to induce endoplasmic reticulum (ER) stress, and reduce resistin gene expression in 3T3-L1 mouse adipocytes. The aim of the present study was to examine whether ER stress affects resistin gene expression in human monocytes.
The relationship between resistin messenger ribonucleic acid (mRNA) and ER stress markers mRNA was analyzed by reverse transcription polymerase chain reaction in isolated monocytes of 30 healthy volunteers. The effect of endotoxin/lipopolysaccharides or tunicamycin on resistin gene expression was analyzed in THP-1 human monocytes. Signaling pathways leading to resistin mRNA were assessed by the knockdown using small interfering RNA or overexpression of key molecules involved in unfolded protein response.
Resistin mRNA was positively associated with immunoglobulin heavy chain-binding protein (BiP) or CAAT/enhancer binding protein-α homologous protein (CHOP) mRNA in human isolated monocytes. In THP-1 cells, lipopolysaccharides increased mRNA of BiP, pancreatic endoplasmic reticulum eukaryotic initiation factor 2α kinase (PERK) and CHOP, as well as resistin. Tunicamycin also increased resistin mRNA. This induction appeared to be dose- and time-dependent. Tunicamycin-induced resistin mRNA was inhibited by chemical chaperone, 4-phenylbutyric acid. The knockdown of either PERK, activating transcription factor 4 (ATF4) or CHOP reduced tunicamycin-induced resistin mRNA. Conversely, overexpression of ATF4 or CHOP increased resistin mRNA.
Endoplasmic reticulum stress induced by tunicamycin increased resistin mRNA through the PERK-ATF4-CHOP pathway in THP-1 human monocytes. ER stress could lead to insulin resistance through enhanced resistin gene expression in human monocytes.
目的/引言：抵抗素是脂肪细胞分泌的一种蛋白，它会导致小鼠胰岛素抵抗。在人类中，抵抗素基因主要在单核细胞和巨噬细胞中表达。已知衣霉素可诱导内质网（ER）应激，并降低 3T3-L1 小鼠脂肪细胞中的抵抗素基因表达。本研究旨在探讨 ER 应激是否会影响人单核细胞中的抵抗素基因表达。
通过逆转录聚合酶链反应分析 30 名健康志愿者分离的单核细胞中抵抗素信使 RNA（mRNA）与 ER 应激标志物 mRNA 之间的关系。分析内毒素/脂多糖或衣霉素对 THP-1 人单核细胞中抵抗素基因表达的影响。通过使用小干扰 RNA 或过表达参与未折叠蛋白反应的关键分子来评估导致抵抗素 mRNA 的信号通路。
在人分离的单核细胞中，抵抗素 mRNA 与免疫球蛋白重链结合蛋白（BiP）或 CAAT/增强子结合蛋白-α同源蛋白（CHOP）mRNA 呈正相关。在 THP-1 细胞中，脂多糖增加了 BiP、胰腺内质网起始因子 2α 激酶（PERK）和 CHOP 的 mRNA，以及抵抗素的 mRNA。衣霉素也增加了抵抗素 mRNA。这种诱导似乎呈剂量和时间依赖性。化学伴侣 4-苯丁酸可抑制衣霉素诱导的抵抗素 mRNA。PERK、激活转录因子 4（ATF4）或 CHOP 的敲低均降低了衣霉素诱导的抵抗素 mRNA。相反，ATF4 或 CHOP 的过表达增加了抵抗素 mRNA。
衣霉素诱导的内质网应激通过 THP-1 人单核细胞中的 PERK-ATF4-CHOP 通路增加抵抗素 mRNA。ER 应激可通过增强人单核细胞中的抵抗素基因表达导致胰岛素抵抗。
