Department of Biochemistry and Molecular Biology, Hengyang Medical School, University of South China, Hengyang 421001, China.
Key Laboratory of Ecological Environment and Critical Human Diseases Prevention of Hunan Province Department of Education, Hengyang Medical School, University of South China, Hengyang 421001, China.
Acta Biochim Biophys Sin (Shanghai). 2022 Mar 25;54(3):370-377. doi: 10.3724/abbs.2022004.
Oxidative stress and endoplasmic reticulum (ER) stress play crucial roles in pancreatic β cell destruction, leading to the development and progression of type 1 diabetes mellitus (T1DM). Curcumin, extracted from plant turmeric, possesses multiple bioactivities such as antioxidant, anti-inflammatory and anti-apoptosis properties and . However, it remains unknown whether curcumin improves ER stress to prevent β cells from apoptosis. In this study, we aim to investigate the role and mechanism of curcumin in ameliorating HO-induced injury in MIN6 (a mouse insulinoma cell line) cells. Cell viability is examined by CCK8 assay. Hoechst 33258 staining, TUNEL and flow cytometric assay are performed to detect cell apoptosis. The relative amounts of reactive oxygen species (ROS) are measured by DCFH-DA. WST-8 is used to determine the total superoxide dismutase (SOD) activity. Protein expressions are determined by western blot analysis and immunofluorescence staining. Pretreatment with curcumin prevents MIN6 cells from HO-induced cell apoptosis. Curcumin decreases ROS generation and inhibits protein kinase like ER kinase (PERK)-C/EBP homologous protein (CHOP) signaling axis, one of the critical branches of ER stress pathway. Moreover, incubation with curcumin activates silent information regulator 1 (SIRT1) expression and subsequently decreases the expression of CHOP. Additionally, EX527, a specific inhibitor of SIRT1, blocks the protective effect of curcumin on MIN6 cells exposed to HO. In sum, curcumin inhibits the PERK-CHOP pathway of ER stress mediated by SIRT1 and thus ameliorates HO-induced MIN6 cell apoptosis, suggesting that curcumin and SIRT1 may provide a potential therapeutic approach for T1DM.
氧化应激和内质网（ER）应激在胰岛β细胞破坏中起关键作用，导致 1 型糖尿病（T1DM）的发生和发展。姜黄素是从植物姜黄中提取的，具有多种生物活性，如抗氧化、抗炎和抗细胞凋亡作用。然而，目前尚不清楚姜黄素是否通过改善 ER 应激来防止β细胞凋亡。在这项研究中，我们旨在研究姜黄素在改善 HO 诱导的 MIN6（一种小鼠胰岛素瘤细胞系）细胞损伤中的作用和机制。通过 CCK8 测定法检测细胞活力。通过 Hoechst 33258 染色、TUNEL 和流式细胞术检测细胞凋亡。通过 DCFH-DA 测定活性氧（ROS）的相对含量。使用 WST-8 测定总超氧化物歧化酶（SOD）活性。通过 Western blot 分析和免疫荧光染色测定蛋白表达。姜黄素预处理可防止 MIN6 细胞受到 HO 诱导的细胞凋亡。姜黄素可减少 ROS 的产生，并抑制蛋白激酶样内质网激酶（PERK）-C/EBP 同源蛋白（CHOP）信号通路，这是 ER 应激途径的关键分支之一。此外，用姜黄素孵育可激活沉默信息调节因子 1（SIRT1）的表达，随后降低 CHOP 的表达。此外，SIRT1 的特异性抑制剂 EX527 阻断了姜黄素对暴露于 HO 的 MIN6 细胞的保护作用。总之，姜黄素通过 SIRT1 抑制 ER 应激的 PERK-CHOP 途径，从而改善 HO 诱导的 MIN6 细胞凋亡，这表明姜黄素和 SIRT1 可能为 T1DM 提供一种潜在的治疗方法。
