Yu Jia, Liu Qian, Zhang Yuejiao, Xu Lingfeng, Chen Xiaohua, He Feng, Zhang Mian, Yang Hongxu, Yu Shibin, Liu Xin, Wu Yaoping, Wang Meiqing
Department of Oral Anatomy and Physiology and TMD, College of Stomatology, the Fourth Military Medical University, Xi'an, China.
Department of Stomatology, Air Force Medical Center, PLA, the Fourth Military Medical University, Beijing, China.
Osteoarthritis Cartilage. 2025 Mar;33(3):351-363. doi: 10.1016/j.joca.2024.08.015. Epub 2024 Dec 25.
Abnormal mechanical stress is intimately coupled with osteoarthritis. Microtubules play a vital role in the regulation of mechanotransduction and intracellular transport. The purpose of the present study was to investigate the impact of stress-induced microtubule impairment on intracellular transport and lipid droplet (LD) accumulation in chondrocytes.
Rats were subjected to unilateral anterior crossbite (UAC), which is inducible for degeneration of temporomandibular joint (TMJ) cartilage. Chondrocytes derived from rat TMJ cartilage were subjected to fluid flow shear stress (FFSS) and analyzed via LCMS/MS-based proteomics. The microtubule destabilization agent nocodazole and/or the microtubule stabilizer docetaxel were used in the UAC and FFSS models.
In both FFSS- and UAC-treated chondrocytes, decreased acetylated α-Tubulin (ac-Tubulin) expression and LD accumulation were observed. Proteomic data revealed increased levels of the LD-associated protein perilipin 3 (Plin3) and decreased levels of cytoskeleton components in FFSS-treated chondrocytes. Live-cell imaging revealed that the colocalization of LDs with lysosomes was significantly decreased after FFSS treatment. Impairment of microtubules by nocodazole reduced the protein level of ac-Tubulin and disrupted the Hsc70-mediated interaction between Plin3 and Lamp2a, as shown by co-IP assays. In contrast, docetaxel reversed the suppression of ac-Tubulin expression, reduced the accumulation of LDs, and decreased the expression of Plin3 in chondrocytes exposed to FFSS and UAC, and docetaxel ameliorated UAC-induced osteoarthritic lesions in the TMJ cartilage.
Microtubule impairment under aberrant stress conditions disrupts intracellular transport and blocks lipophagy, causing LD accumulation in chondrocytes. Microtubule stabilization could be a new approach for treating stress-induced cartilage degeneration.
异常机械应力与骨关节炎密切相关。微管在机械转导和细胞内运输的调节中起着至关重要的作用。本研究的目的是探讨应激诱导的微管损伤对软骨细胞内运输和脂滴（LD）积累的影响。
对大鼠进行单侧前牙反咬合（UAC），这可诱导颞下颌关节（TMJ）软骨退变。对源自大鼠TMJ软骨的软骨细胞施加流体流动剪切应力（FFSS），并通过基于液相色谱-质谱联用（LCMS/MS）的蛋白质组学进行分析。在UAC和FFSS模型中使用微管去稳定剂诺考达唑和/或微管稳定剂多西他赛。
在FFSS处理和UAC处理的软骨细胞中，均观察到乙酰化α-微管蛋白（ac-Tubulin）表达降低和LD积累。蛋白质组学数据显示，FFSS处理的软骨细胞中，与LD相关的蛋白围脂滴蛋白3（Plin3）水平升高，细胞骨架成分水平降低。活细胞成像显示，FFSS处理后，LD与溶酶体的共定位显著降低。共免疫沉淀分析表明，诺考达唑对微管的损伤降低了ac-Tubulin的蛋白水平，并破坏了热休克蛋白70（Hsc70）介导的Plin3与溶酶体相关膜蛋白2a（Lamp2a）之间的相互作用。相反，多西他赛可逆转FFSS处理和UAC处理的软骨细胞中ac-Tubulin表达的抑制，减少LD的积累，并降低Plin3的表达，且多西他赛可改善UAC诱导的TMJ软骨骨关节炎病变。
异常应激条件下的微管损伤会破坏细胞内运输并阻断脂肪自噬，导致软骨细胞中LD积累。微管稳定化可能是治疗应激诱导的软骨退变的一种新方法。
