Cheng Deliang, Zhang Lijun, Liang Xiaoju
Department of Hand Surgery, Honghui Hospital, Xi'an Jiaotong University, Xi'an, China.
Department of Pediatric Orthopedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, China.
Clin Exp Pharmacol Physiol. 2023 Jan;50(1):50-58. doi: 10.1111/1440-1681.13721. Epub 2022 Oct 4.
Dexamethasone (Dex) is reported to cause bone growth retardation in children, which is associated with the increased apoptosis and decreased proliferation of growth plate chondrocytes. Sirtuin 1 (SIRT1) plays an important role in chondrocyte function and homeostasis. Thus, we further explored the regulatory mechanism of SIRT1 in Dex-induced growth plate chondrocyte dysfunction. SIRT1 expression was detected in Dex-treated growth plate chondrocytes using RT-qPCR and western blot assay. The modulation of SIRT1 on SOX2 expression was evaluated. Besides, we identified that SIRT1 was targeted by miR-211-5p using TargetScan and RNA pull-down assay. A loss-of-function assay was performed to evaluate the effects of miR-211-5p on Dex-induced growth plate chondrocyte dysfunction in vitro and in vivo. We found that SIRT1 was downregulated in Dex-treated growth plate chondrocytes. The expression of SOX2 was upregulated by overexpression SIRT1. Meanwhile, downregulation of SOX2 weakened the positive function of SIRT1 overexpression on Dex-induced growth plate chondrocytes dysfunction. Subsequently, we confirmed that SIRT1 was targeted by miR-211-5p. MiR-211-5p inhibitor increased the expression levels of SIRT1 and SOX2, and restored the Dex-treated growth plate chondrocyte function. Animal assays further demonstrated that the effects of miR-211-5p on the growth plate chondrogenesis. In conclusion, our data suggest that SIRT1 exerts a protective effect on growth plate chondrocyte under Dex stimulation. MiR-211-5p/SIRT1/SOX2 axis regulates the process of Dex-inhibited growth plate chondrogenesis.
据报道，地塞米松（Dex）会导致儿童骨骼生长迟缓，这与生长板软骨细胞凋亡增加和增殖减少有关。沉默调节蛋白1（SIRT1）在软骨细胞功能和稳态中起重要作用。因此，我们进一步探讨了SIRT1在地塞米松诱导的生长板软骨细胞功能障碍中的调节机制。使用RT-qPCR和蛋白质免疫印迹法检测地塞米松处理的生长板软骨细胞中SIRT1的表达。评估了SIRT1对SOX2表达的调节作用。此外，我们使用TargetScan和RNA下拉实验确定SIRT1是miR-211-5p的靶标。进行功能丧失实验以评估miR-211-5p在体外和体内对地塞米松诱导的生长板软骨细胞功能障碍的影响。我们发现地塞米松处理的生长板软骨细胞中SIRT1表达下调。过表达SIRT1可上调SOX2的表达。同时，SOX2的下调削弱了SIRT1过表达对地塞米松诱导的生长板软骨细胞功能障碍的正向作用。随后，我们证实SIRT1是miR-211-5p的靶标。miR-211-5p抑制剂可增加SIRT1和SOX2的表达水平，并恢复地塞米松处理的生长板软骨细胞功能。动物实验进一步证明了miR-211-5p对生长板软骨形成的影响。总之，我们的数据表明SIRT1在地塞米松刺激下对生长板软骨细胞具有保护作用。miR-211-5p/SIRT1/SOX2轴调节地塞米松抑制的生长板软骨形成过程。
