Bone and Joint Surgery, Shenzhen Baoan Shiyan People's Hospital, China.
Department of Sports Medicine, Peking University Shenzhen Hospital, China.
Biochem Biophys Res Commun. 2019 Aug 13;516(1):209-214. doi: 10.1016/j.bbrc.2019.06.016. Epub 2019 Jun 14.
Chondrocyte death due to apoptosis is central for osteoarthritis (OA) pathogenesis. The family with sequence similarity 3A (FAM3A) is a mitochondrial protein that plays an important role for cellular adaptation to stress and cell survival. Yet, whether FAM3A is associated with chondrocyte apoptosis and OA pathogenesis remains uncharacterized. In this study, we found that FAM3A expression was downregulated in cartilage tissue from an experimental OA mouse model. Besides, FAM3A expression was also reduced in chondrocytes treated with interleukin-1β (IL-1β), an inflammatory cytokine that promotes cartilage degradation. Moreover, we discovered that FAM3A attenuated chondrocyte apoptosis induced by IL-1β treatment in vitro, suggesting a protective effect of FAM3A against chondrocyte apoptosis. Moreover, mechanistically, FAM3A activated PI3K/Akt/mTOR pathway in IL-1β-treated chondrocytes, and blockade of PI3K/Akt/mTOR pathway with specific inhibitors, wortmannin and LY294002, diminished FAM3A effect on IL-1β-induced chondrocyte apoptosis, hence demonstrating that FAM3A attenuates IL-1β-induced chondrocyte apoptosis through activating the pro-survival PI3K/Akt/mTOR pathway. In conclusion, our study may identify FAM3A as a potential regulator of chondrocyte apoptosis involved in OA pathogenesis.
软骨细胞凋亡是骨关节炎(OA)发病机制的核心。家族与序列相似性 3A(FAM3A)是一种线粒体蛋白,在细胞适应应激和细胞存活方面发挥着重要作用。然而,FAM3A 是否与软骨细胞凋亡和 OA 发病机制有关尚不清楚。在这项研究中,我们发现 FAM3A 在实验性 OA 小鼠模型的软骨组织中表达下调。此外,FAM3A 在接受白细胞介素 1β(IL-1β)处理的软骨细胞中的表达也降低了,IL-1β 是一种促进软骨降解的炎症细胞因子。此外,我们发现 FAM3A 可减轻 IL-1β 处理诱导的软骨细胞凋亡,表明 FAM3A 对软骨细胞凋亡具有保护作用。此外,从机制上讲,FAM3A 在 IL-1β 处理的软骨细胞中激活了 PI3K/Akt/mTOR 通路,而特异性抑制剂wortmannin 和 LY294002 阻断 PI3K/Akt/mTOR 通路,则减弱了 FAM3A 对 IL-1β 诱导的软骨细胞凋亡的作用,因此表明 FAM3A 通过激活抗凋亡的 PI3K/Akt/mTOR 通路来减轻 IL-1β 诱导的软骨细胞凋亡。总之,我们的研究可能确定 FAM3A 为参与 OA 发病机制的软骨细胞凋亡的潜在调节剂。
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