Center for Translational Medicine, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, China; School of Pharmaceutical Sciences, Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine, Shiyan, Hubei, China.
Center for Translational Medicine, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, China.
Int Immunopharmacol. 2024 Apr 20;131:111893. doi: 10.1016/j.intimp.2024.111893. Epub 2024 Mar 20.
This study aims to investigate the role and underlying mechanisms of Sirt1 in the pathophysiological process of OA. Safranine O and HE staining were utilized to identify pathological changes in the cartilage tissue. Immunohistochemistry was employed to evaluate the expression levels of proteins. IL-1β treatment and TamCartSirt1 mice were utilized to induce OA model both in vitro and in vivo. Key autophagy-related transcription factors, autophagy-related genes, and chondrocyte extracellular matrix (ECM) breakdown enzyme markers were examined using multi assays. Immunofluorescence staining revealed subcellular localization and gene expression patterns. ChIP assay and Co-immunoprecipitation assay were conducted to investigate the interactions between FoxO1 and the promoter regions of Atg7 and Sirt1. Our results demonstrate that Sirt1 deficiency exhibited inhibitory effects on ECM synthesis and autophagy, as well as exacerbated angiogenesis. Moreover, Atg7, Foxo1, and Sirt1 could form a protein complex. Sirt1 was observed to facilitate nuclear translocation of FoxO1, enhancing its transcriptional activity. Furthermore, FoxO1 was found to bind to the promoter regions of Atg7 and Sirt1, potentially regulating their expression. This study provides valuable insights into the involvement of Sirt1-Atg7-FoxO1 loop in OA, opening new avenues for targeted therapeutic interventions aiming to mitigate cartilage degradation and restore joint function.
本研究旨在探讨 Sirt1 在 OA 病理生理过程中的作用和潜在机制。番红 O 和 HE 染色用于鉴定软骨组织的病理变化。免疫组织化学用于评估蛋白表达水平。采用 IL-1β 处理和 TamCartSirt1 小鼠在体外和体内诱导 OA 模型。使用多种检测方法评估关键自噬相关转录因子、自噬相关基因和软骨细胞细胞外基质（ECM）降解酶标志物。免疫荧光染色显示亚细胞定位和基因表达模式。ChIP 检测和 Co-immunoprecipitation 检测用于研究 FoxO1 与 Atg7 和 Sirt1 启动子区域之间的相互作用。我们的结果表明，Sirt1 缺失对 ECM 合成和自噬具有抑制作用，并加剧了血管生成。此外，Atg7、Foxo1 和 Sirt1 可以形成一个蛋白质复合物。观察到 Sirt1 促进 FoxO1 的核转位，增强其转录活性。此外，发现 FoxO1 与 Atg7 和 Sirt1 的启动子区域结合，可能调节它们的表达。本研究为 Sirt1-Atg7-FoxO1 环在 OA 中的作用提供了有价值的见解，为旨在减轻软骨降解和恢复关节功能的靶向治疗干预开辟了新途径。
