Biochemistry and Molecular Biology Department, Research Division, Dasman Diabetes Institute, Kuwait City 15462, Kuwait.
Research Division, Dasman Diabetes Institute, Kuwait City 15462, Kuwait.
Int J Mol Sci. 2020 Mar 17;21(6):2056. doi: 10.3390/ijms21062056.
Epoxide hydrolase 2 (EPHX2) is an emerging therapeutic target in several immunometabolic disorders. EPHX2 metabolizes anti-inflammatory epoxyeicosatrienoic acids into pro-inflammatory diols. The contribution of EPHX2 activity to human obesity remains unexplored. We compared the expression of EPHX2 between lean and obese humans ( = 20 each) in subcutaneous adipose tissue (SAT) and peripheral blood mononuclear cells (PBMCs) using RT-PCR, Western Blot analysis, immunohistochemistry, and confocal microscopy before and after a 3-month physical activity regimen. We also assessed EPHX2 levels during preadipocyte differentiation in humans and mice. EPHX2 mRNA and protein expression were significantly elevated in obese subjects, with concomitant elevated endoplasmic reticulum (ER) stress components (the 78-kDa glucose-regulated protein; GRP78, and the Activating transcription factor 6; ATF6) and inflammatory markers (Tumor necrosis factor-α; TNFα, and Interleukin 6; IL6) as compared to controls ( < 0.05). EPHX2 mRNA levels strongly correlated with adiposity markers. In obese individuals, physical activity attenuated EPHX2 expression levels in both the SAT and PBMCs, with a parallel decrease in ER stress and inflammation markers. EPHX2 expression was also elevated during differentiation of both human primary and 3T3-L1 mouse preadipocytes. Mediators of cellular stress (palmitate, homocysteine, and macrophage culture medium) also increased EPHX2 expression in 3T3-L1 preadipocytes. Our findings suggest that EPHX2 upregulation is linked to ER stress in adiposity and that physical activity may attenuate metabolic stress by reducing EPHX2 expression.
环氧水解酶 2（EPHX2）是几种免疫代谢疾病的新兴治疗靶标。EPHX2 将抗炎性环氧二十碳三烯酸代谢为促炎二醇。EPHX2 活性对人类肥胖的贡献仍未得到探索。我们使用 RT-PCR、Western Blot 分析、免疫组织化学和共聚焦显微镜，比较了瘦人和肥胖者（每组各 20 人）在下腹部脂肪组织（SAT）和外周血单核细胞（PBMC）中的 EPHX2 表达，在进行 3 个月的体育锻炼方案前后。我们还评估了人类和小鼠前体脂肪细胞分化过程中的 EPHX2 水平。与对照组相比，肥胖患者的 EPHX2 mRNA 和蛋白表达显着升高，同时内质网（ER）应激成分（78 kDa 葡萄糖调节蛋白；GRP78 和激活转录因子 6；ATF6）和炎症标志物（肿瘤坏死因子-α；TNFα 和白细胞介素 6；IL6）也升高（<0.05）。EPHX2 mRNA 水平与肥胖标志物强烈相关。在肥胖个体中，体育锻炼可减弱 SAT 和 PBMC 中 EPHX2 的表达水平，同时 ER 应激和炎症标志物也降低。EPHX2 的表达也在人类原代和 3T3-L1 小鼠前体脂肪细胞的分化过程中升高。细胞应激的介质（棕榈酸、同型半胱氨酸和巨噬细胞培养基）也增加了 3T3-L1 前体脂肪细胞中的 EPHX2 表达。我们的研究结果表明，EPHX2 的上调与肥胖中的 ER 应激有关，而体育锻炼可能通过降低 EPHX2 表达来减轻代谢应激。
