Departments of Orthopedics and Traumatology, Nanjing Lishui District Hospital of Traditional Chinese Medicine, Nanjing, 211200 Jiangsu Province, China.
Department of Orthopedics and Traumatology, Qinhuai District Hospital of Traditional Chinese Medicine, Nanjing, 210006 Jiangsu Province, China.
J Immunol Res. 2022 Mar 8;2022:4370873. doi: 10.1155/2022/4370873. eCollection 2022.
Osteoarthritis (OA) serves as one of the most prevalent types of joint disorders and is a leading cause of symptoms of stiffness, swelling, and arthralgia. Circular RNAs (circRNAs) have been reported to participate in various cellular processes by competing with microRNAs. Meanwhile, cyclinD1 (CCND1) is a key cell cycle regulatory protein and plays a crucial role in OA progression. Nevertheless, the function of circRHOT1 in the modulation of OA progression is still obscure. Here, we explored the effect of circRHOT1 on autophagy and extracellular matrix (ECM) in OA.
The expression of circRHOT1 and autophagy markers was detected in OA samples. The effect of circRHOT1 on OA was analyzed in the OA rat model. The function of circRHOT1 in the regulation of OA was assessed by CCK-8, colony formation, flow cytometry analysis, quantitative real-time PCR, Western blot analysis, and luciferase reporter gene assay in chondrocytes.
We observed that autophagy markers, including LC3 and beclin1, were repressed in clinical OA samples. The expression of circRHOT1 and CCND1 was induced but the miR-142-5p expression was reduced in clinical OA samples. The miR-142-5p expression was negatively correlated with circRHOT1 and CCND1, and the circRHOT1 expression was positively associated with CCND1 in clinical OA samples. Meanwhile, the apoptosis was induced in OA rats but the depletion of circRHOT1 could block the phenotype in the rats. The articular cartilage degeneration was promoted in OA rats, while the knockdown of circRHOT1 repressed the degeneration. The serum levels of CTX-II and COMP were increased in OA rats, and the silencing of circRHOT1 downregulated levels of these proteins. In addition, the expression of collagen II and aggrecan was promoted by the depletion of circRHOT1 in the OA rats. Significantly, the expression of LC3 and beclin1 was suppressed in OA rats, in which the knockdown of circRHOT1 could reverse the effect. Moreover, the depletion of circRHOT1 repressed the cell viability and proliferation but induced apoptosis of chondrocytes. The expression levels of LC3, beclin1, collagen II, and aggrecan were induced by circRHOT1 knockdown. Mechanically, circRHOT1 was able to enhance the CCND1 expression by sponging miR-142-5p in chondrocytes. The overexpression of CCND1 or the inhibition of miR-142-5p reversed circRHOT1 depletion-mediated chondrocyte phenotypes.
Circular RNA RHOT1 enhances the CCND1 expression by sponging miR-142-5p to inhibit chondrocyte autophagy and promote chondrocyte proliferation in osteoarthritis. Our findings provided a promising therapeutic target for OA.
骨关节炎 (OA) 是最常见的关节疾病类型之一，也是导致僵硬、肿胀和关节痛症状的主要原因。环状 RNA (circRNA) 已被报道通过与 microRNA 竞争参与各种细胞过程。同时，细胞周期蛋白 D1 (CCND1) 是细胞周期调控的关键蛋白，在 OA 进展中发挥着关键作用。然而，circRHOT1 在调节 OA 进展中的功能仍然不清楚。在这里，我们探讨了 circRHOT1 对 OA 中自噬和细胞外基质 (ECM) 的影响。
检测 OA 样本中 circRHOT1 和自噬标志物的表达。在 OA 大鼠模型中分析 circRHOT1 对 OA 的影响。通过 CCK-8、集落形成、流式细胞术分析、实时定量 PCR、Western blot 分析和荧光素酶报告基因分析评估 circRHOT1 在调控 OA 中的作用。
我们观察到临床 OA 样本中自噬标志物 LC3 和 beclin1 的表达受到抑制。临床 OA 样本中 circRHOT1 和 CCND1 的表达上调，但 miR-142-5p 的表达降低。miR-142-5p 的表达与 circRHOT1 和 CCND1 呈负相关，与临床 OA 样本中的 CCND1 呈正相关。同时，OA 大鼠中诱导了细胞凋亡，但 circRHOT1 的耗竭可以阻断大鼠中的表型。OA 大鼠中关节软骨退化被促进，而 circRHOT1 的敲低抑制了退化。OA 大鼠中 CTX-II 和 COMP 的血清水平升高，circRHOT1 的沉默下调了这些蛋白质的水平。此外，OA 大鼠中 circRHOT1 的耗竭促进了胶原 II 和聚集蛋白聚糖的表达。显著的是，OA 大鼠中 LC3 和 beclin1 的表达受到抑制，circRHOT1 的敲低可以逆转这种作用。此外，circRHOT1 的耗竭抑制了软骨细胞的活力和增殖，但诱导了其凋亡。circRHOT1 敲低后 LC3、beclin1、胶原 II 和聚集蛋白聚糖的表达水平增加。机制上，circRHOT1 通过海绵吸附 miR-142-5p 增强 CCND1 的表达在软骨细胞中。CCND1 的过表达或 miR-142-5p 的抑制逆转了 circRHOT1 耗竭介导的软骨细胞表型。
环状 RNA RHOT1 通过海绵吸附 miR-142-5p 增强 CCND1 的表达，抑制骨关节炎中的软骨细胞自噬，促进软骨细胞增殖。我们的研究结果为 OA 提供了一个有前途的治疗靶点。
