Department of Joint Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
Oxid Med Cell Longev. 2022 Aug 5;2022:5781660. doi: 10.1155/2022/5781660. eCollection 2022.
tRNA-derived fragments (tRFs) have been reported to have critical regulatory roles in osteoarthritis (OA). Recent studies have suggested that autophagy promotes the homeostasis of the extracellular matrix of chondrocytes in OA. However, the role of tRFs in posttranscriptional gene regulation during autophagy in OA is unknown. Therefore, we explored the role of tRF-5009A in the posttranscriptional gene regulation of autophagy and cartilage degeneration in OA. Using RNA sequencing, we identified tRF-5009A, the tRNA-derived fragment, in OA tissues and explored its expression by quantitative reverse transcription PCR and fluorescence in situ hybridization. We further investigated the relationship between the expression of tRF-5009A and clinical factors in OA. Chondrocytes were transfected with a tRF-5009A inhibitor or mimic to determine their functions, including in relation to autophagy and the cartilage phenotype. A rescue experiment and dual-luciferase reporter assay were conducted to determine whether the 3'-untranslated region (UTR) of mTOR contains a tRF-5009A-binding site. tRF-5009A was downregulated in the cartilage of OA knees, especially in damaged areas. mTOR was highly expressed in damaged cartilage and negatively correlated with the expression of tRF-5009A; transfection with a tRF-5009A inhibitor promoted the expression of mTOR and suppressed autophagy, whereas transfection with a tRF-5009A mimic had the opposite effect. A dual-luciferase reporter assay showed that tRF-5009A silenced the expression of mTOR by binding to its 3'-UTR. Thus, tRF-5009A regulates autophagy and cartilage degeneration in OA by targeting mTOR. In summary, these findings provide an additional tool for the clinical diagnosis and novel targeted therapy of OA.
tRNA 衍生片段 (tRFs) 在骨关节炎 (OA) 中具有关键的调节作用。最近的研究表明，自噬促进 OA 软骨细胞细胞外基质的动态平衡。然而，tRFs 在 OA 自噬过程中转录后基因调控中的作用尚不清楚。因此，我们探讨了 tRF-5009A 在 OA 自噬和软骨退变中转录后基因调控中的作用。我们使用 RNA 测序技术鉴定了 OA 组织中的 tRF-5009A，并通过定量逆转录 PCR 和荧光原位杂交技术探索其表达情况。我们进一步研究了 tRF-5009A 在 OA 中的表达与临床因素之间的关系。通过转染 tRF-5009A 抑制剂或模拟物来研究软骨细胞的功能，包括自噬和软骨表型。进行了挽救实验和双荧光素酶报告基因检测实验，以确定 mTOR 的 3'-非翻译区 (UTR) 是否含有 tRF-5009A 结合位点。OA 膝关节软骨中 tRF-5009A 表达下调，特别是在受损区域。mTOR 在受损软骨中高表达，与 tRF-5009A 的表达呈负相关；转染 tRF-5009A 抑制剂促进 mTOR 的表达并抑制自噬，而转染 tRF-5009A 模拟物则有相反的效果。双荧光素酶报告基因检测实验表明，tRF-5009A 通过结合 mTOR 的 3'-UTR 来沉默其表达。因此，tRF-5009A 通过靶向 mTOR 来调节 OA 中的自噬和软骨退变。总之，这些发现为 OA 的临床诊断和新型靶向治疗提供了额外的工具。
