Ding Jie, Chen Yong, Zhao Ying-Jie, Chen Fan, Dong Lei, Zhang Hai-Lin, Hu Wei-Rong, Li Shu-Fang, Zhou Ren-Peng, Hu Wei
Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei 230601, China.
The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China.
Biochem Pharmacol. 2022 Aug;202:115107. doi: 10.1016/j.bcp.2022.115107. Epub 2022 May 25.
Osteoarthritis (OA) is a common and debilitating chronic joint disease, which is characterized by degeneration of articular cartilage and the aging of chondrocytes. Acid-sensitive ion channel 1a (ASIC1a) is a proton-activated cationic channel abundant in chondrocytes, which senses and regulates joint cavity pH. Our previous study demonstrated that ASIC1a was involved in acid-induced rat articular chondrocyte senescence, but the mechanistic basis remained unclear. In this study, we explored the mechanism of ASIC1a in chondrocyte senescence and OA. The results showed that senescence-related-β-galactosidase, senescence-related markers (p53 and p21) and the autophagy-related protein Beclin-1 were found to be increased, but Lamin B1 was found to be reduced with acid (pH 6.0) treatment. These effects were inhibited by ASIC1a-specific blocker psalmotoxin-1 or ASIC1a-short hairpin RNA respectively in chondrocytes. Moreover, Silencing of Lamin B1 enhanced ASIC1a-mediated chondrocyte senescence, this effect was reversed by overexpression of Lamin B1, indicating that Lamin B1 was involved in ASIC1a-mediated chondrocyte senescence. Further, blockade of ASIC1a inhibits acid-induced autophagosomes and Beclin-1 protein expression, suggesting that ASIC1a is involved in acid-induced chondrocyte autophagy. Blocking autophagy with chloroquine inhibited Beclin-1 and increased Lamin B1 in acid-induced chondrocyte senescence. We further demonstrated that ASIC1a-mediated reduction of Lamin B1 expression was caused by autophagy pathway-dependent protein degradation. Finally, blocking ASIC1a protected cartilage tissue, restored Lamin B1 levels and inhibited chondrocyte senescence in a rat OA model. In summary, these findings suggest that ASIC1a may promote Lamin B1 degradation to mediate osteoarthritis chondrocyte senescence through the autophagy pathway.
骨关节炎（OA）是一种常见且使人衰弱的慢性关节疾病，其特征在于关节软骨退变和软骨细胞老化。酸敏感离子通道1a（ASIC1a）是一种在软骨细胞中丰富的质子激活阳离子通道，可感知并调节关节腔pH值。我们之前的研究表明ASIC1a参与酸诱导的大鼠关节软骨细胞衰老，但其机制基础仍不清楚。在本研究中，我们探究了ASIC1a在软骨细胞衰老和骨关节炎中的作用机制。结果显示，用酸（pH 6.0）处理后，衰老相关β-半乳糖苷酶、衰老相关标志物（p53和p21）以及自噬相关蛋白Beclin-1水平升高，而核纤层蛋白B1水平降低。在软骨细胞中，ASIC1a特异性阻滞剂蜂毒素-1或ASIC1a短发夹RNA分别抑制了这些效应。此外，沉默核纤层蛋白B1增强了ASIC1a介导的软骨细胞衰老，而核纤层蛋白B1的过表达则逆转了这种效应，表明核纤层蛋白B1参与了ASIC1a介导的软骨细胞衰老。此外，阻断ASIC1a可抑制酸诱导的自噬体和Beclin-1蛋白表达，提示ASIC1a参与酸诱导的软骨细胞自噬。用氯喹阻断自噬可抑制酸诱导的软骨细胞衰老中的Beclin-1表达并增加核纤层蛋白B1水平。我们进一步证明，ASIC1a介导的核纤层蛋白B1表达降低是由自噬途径依赖性蛋白降解引起的。最后，在大鼠骨关节炎模型中，阻断ASIC1a可保护软骨组织，恢复核纤层蛋白B1水平并抑制软骨细胞衰老。总之，这些发现表明ASIC1a可能通过自噬途径促进核纤层蛋白B1降解，从而介导骨关节炎软骨细胞衰老。
