Liu Ruoxi, Xiao Yi, Huang Sihua, Wu Hao, Dong Jun, Zeng Sixiang, Li Yongwei, Ye Jintao, Wu Wei, Wang Mengxin, Zhang Sanpeng, Lin Zhaoxing, Song Huanjin
Department of Orthopaedics, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
Shaanxi Provincial Center for Disease Control and Prevention, Xi'an, China.
Mol Immunol. 2025 Jun;182:62-75. doi: 10.1016/j.molimm.2025.03.016. Epub 2025 Apr 3.
The primary mechanisms underlying cartilage destruction in Kashin-Beck disease (KBD) involve excessive chondrocyte death and extracellular matrix (ECM) degradation. While long non-coding RNA XIST (lncRNA XIST) has been implicated in promoting chondrocyte injury in osteoarthritis (OA), its role in KBD-related chondrocyte injury remains poorly understood. In this study, joint tissues were collected from four healthy and four KBD-affected children, as well as five healthy and five KBD-affected adults, to assess the expression of lncRNA XIST. The results revealed a significant upregulation of lncRNA XIST in the cartilage tissues of KBD patients. To model KBD-induced chondrocyte damage in vitro, hypertrophic ATDC5 cells were exposed to 10 ng/ml T-2 toxin for 24 hours, which resulted in increased lncRNA XIST expression. Silencing lncRNA XIST was found to mitigate T-2 toxin-induced ECM degradation and chondrocyte apoptosis by alleviating defects in mitochondrial autophagy and dysfunction. Mechanistically, lncRNA XIST promoted the methylation of the BNIP3 promoter by recruiting DNA methyltransferases (DNMTs) to the BNIP3 promoter region, thereby suppressing BNIP3-mediated mitophagy and exacerbating mitochondrial dysfunction. To establish a KBD rat model, rats were fed a low-selenium diet supplemented with T-2 toxin for four weeks. Knockdown of lncRNA XIST in these rats attenuated articular cartilage damage and apoptosis, while enhancing collagen II expression. In conclusion, lncRNA XIST accelerates KBD progression by inhibiting mitophagy and promoting mitochondrial dysfunction through increased BNIP3 promoter methylation.
大骨节病（KBD）中软骨破坏的主要机制包括软骨细胞过度死亡和细胞外基质（ECM）降解。虽然长链非编码RNA XIST（lncRNA XIST）已被证明与骨关节炎（OA）中软骨细胞损伤的发生有关，但其在KBD相关软骨细胞损伤中的作用仍知之甚少。在本研究中，收集了4名健康儿童、4名患KBD儿童、5名健康成年人以及5名患KBD成年人的关节组织，以评估lncRNA XIST的表达。结果显示，KBD患者软骨组织中lncRNA XIST显著上调。为了在体外模拟KBD诱导的软骨细胞损伤，将肥大的ATDC5细胞暴露于10 ng/ml T-2毒素中24小时，这导致lncRNA XIST表达增加。研究发现，沉默lncRNA XIST可通过减轻线粒体自噬缺陷和功能障碍来减轻T-2毒素诱导的ECM降解和软骨细胞凋亡。机制上，lncRNA XIST通过将DNA甲基转移酶（DNMTs）招募到BNIP3启动子区域来促进BNIP3启动子的甲基化，从而抑制BNIP3介导的线粒体自噬并加剧线粒体功能障碍。为建立KBD大鼠模型，给大鼠喂食低硒饮食并补充T-2毒素，持续四周。在这些大鼠中敲低lncRNA XIST可减轻关节软骨损伤和细胞凋亡，同时增强Ⅱ型胶原蛋白的表达。总之，lncRNA XIST通过抑制线粒体自噬并通过增加BNIP3启动子甲基化促进线粒体功能障碍，从而加速KBD的进展。
