Wu Sha, Zhou Haiqi, Ling Huixian, Sun Yuyan, Luo Ziyu, Ngo ThaiNamanh, Fu Yuanyuan, Wang Wen, Kong Ying
Department of Rehabilitation, The Second Xiangya Hospital of Central South University, Changsha, China.
Apoptosis. 2024 Jun;29(5-6):785-798. doi: 10.1007/s10495-024-01950-9. Epub 2024 Mar 22.
Osteoarthritis (OA) is a common disease in middle-aged and elderly people. An imbalance in calcium ion homeostasis will contribute to chondrocyte apoptosis and ultimately lead to the progression of OA. Transient receptor potential channel 4 (TRPV4) is involved in the regulation of intracellular calcium homeostasis. TRPV4 is expressed in primary cilia, which can sense mechanical stimuli from outside the cell, and its abnormal expression is closely related to the development of OA. Low-intensity pulsed ultrasound (LIPUS) can alleviate chondrocyte apoptosis while the exact mechanism is unclear. In this project, with the aim of revealing the mechanism of action of LIPUS, we proposed to use OA chondrocytes and animal models, LIPUS intervention, inhibition of primary cilia, use TRPV4 inhibitors or TRPV4 agonist, and use Immunofluorescence (IF), Immunohistochemistry (IHC), Western Blot (WB), Quantitative Real-time PCR (QP) to detect the expression of cartilage synthetic matrix and endoplasmic reticulum stress markers. The results revealed that LIPUS altered primary cilia expression, promoted synthetic matrix metabolism in articular chondrocytes and was associated with primary cilia. In addition, LIPUS exerted a active effect on OA by activating TRPV4, inducing calcium inward flow, and facilitating the entry of NF-κB into the nucleus to regulate synthetic matrix gene transcription. Inhibition of TRPV4 altered primary cilia expression in response to LIPUS stimulation, and knockdown of primary cilia similarly inhibited TRPV4 function. These results suggest that LIPUS mediates TRPV4 channels through primary cilia to regulate the process of knee osteoarthritis in mice.
骨关节炎（OA）是中老年人的常见疾病。钙离子稳态失衡会导致软骨细胞凋亡，并最终导致OA的进展。瞬时受体电位通道4（TRPV4）参与细胞内钙稳态的调节。TRPV4在初级纤毛中表达，初级纤毛可感知细胞外的机械刺激，其异常表达与OA的发展密切相关。低强度脉冲超声（LIPUS）可减轻软骨细胞凋亡，但其确切机制尚不清楚。在本项目中，为了揭示LIPUS的作用机制，我们建议使用OA软骨细胞和动物模型，进行LIPUS干预、抑制初级纤毛、使用TRPV4抑制剂或TRPV4激动剂，并使用免疫荧光（IF）、免疫组织化学（IHC）、蛋白质免疫印迹（WB）、定量实时PCR（QP）来检测软骨合成基质和内质网应激标志物的表达。结果显示，LIPUS改变了初级纤毛的表达，促进了关节软骨细胞的合成基质代谢，且与初级纤毛有关。此外，LIPUS通过激活TRPV4、诱导钙内流以及促进NF-κB进入细胞核来调节合成基质基因转录，从而对OA发挥积极作用。抑制TRPV4会改变LIPUS刺激下的初级纤毛表达，而敲除初级纤毛同样会抑制TRPV4功能。这些结果表明，LIPUS通过初级纤毛介导TRPV4通道，从而调节小鼠膝骨关节炎的进程。
