Abstract

Islet transplantation (ITx) is being developed as a treatment for type 1 diabetes mellitus, but hypoxic damage to transplanted islet grafts is an important factor affecting successful transplantation. To investigate the role of sirtuin-1 (SIRT1) under hypoxic injury in INS-1 cells, one type of pancreatic β-cell lines, we used SRT1720 and GW4064 for SIRT1 activation. The small interfering RNA SIRT1 (si-SIRT1) was used to suppress SIRT1 gene expression. We measured cell viability, apoptosis, and the levels of inflammatory cytokines, including tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6), and reactive oxygen species (ROS), under hypoxic conditions. Real-time PCR and Western blot analysis were performed. Cell viability was significantly reduced to 71% and 40% after 4 and 6 h of hypoxic conditions, respectively. Apoptosis increased significantly 2.8-fold and 5.3-fold after 4 and 6 h of hypoxia, respectively. SIRT1 expression was significantly reduced at the mRNA and protein levels during hypoxia. Hypoxic damage significantly increased the TNF-α, IL-6 and ROS levels in INS-1 cells. However, the reduced cell viability and increased inflammatory cytokines from hypoxic damage were ameliorated by SIRT1 activation in INS-1 cells. These results suggest that SIRT1 is a potential target for the protection of pancreatic β-cells against hypoxic damage during ITx.

摘要

胰岛移植 (ITx) 正在开发用于治疗 1 型糖尿病，但移植胰岛移植物的缺氧损伤是影响移植成功的重要因素。为了研究 INS-1 细胞（一种胰腺 β 细胞系）中缺氧损伤下 Sirtuin-1 (SIRT1) 的作用，我们使用 SRT1720 和 GW4064 激活 SIRT1。小干扰 RNA SIRT1 (si-SIRT1) 用于抑制 SIRT1 基因表达。我们在缺氧条件下测量了细胞活力、细胞凋亡和炎性细胞因子的水平，包括肿瘤坏死因子-α (TNF-α)、白细胞介素-6 (IL-6) 和活性氧 (ROS)。进行实时 PCR 和蛋白质印迹分析。在缺氧条件下 4 小时和 6 小时后，细胞活力分别显着降低至 71% 和 40%。缺氧 4 小时和 6 小时后，细胞凋亡分别显着增加 2.8 倍和 5.3 倍。缺氧期间 SIRT1 表达在 mRNA 和蛋白质水平上显着降低。缺氧损伤显着增加了 INS-1 细胞中的 TNF-α、IL-6 和 ROS 水平。然而，在 INS-1 细胞中激活 SIRT1 可以改善缺氧损伤导致的细胞活力降低和炎症细胞因子增加。这些结果表明 SIRT1 是在 ITx 期间保护胰腺 β 细胞免受缺氧损伤的潜在靶标。INS-1 细胞中的 SIRT1 激活可改善缺氧损伤引起的细胞活力降低和炎症细胞因子增加。这些结果表明 SIRT1 是在 ITx 期间保护胰腺 β 细胞免受缺氧损伤的潜在靶标。INS-1 细胞中的 SIRT1 激活可改善缺氧损伤引起的细胞活力降低和炎症细胞因子增加。这些结果表明 SIRT1 是在 ITx 期间保护胰腺 β 细胞免受缺氧损伤的潜在靶标。