Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, China.
Department of Orthopedic, Xiangya Hospital of Central South University, Changsha, China.
Biochim Biophys Acta Mol Basis Dis. 2024 Aug;1870(6):167251. doi: 10.1016/j.bbadis.2024.167251. Epub 2024 May 23.
Exposure of articular cartilage to excessive mechanical loading is closely related to the pathogenesis of osteoarthritis (OA). However, the exact molecular mechanism by which excessive mechanical loading drives OA remains unclear. In vitro, primary chondrocytes were exposed to cyclic tensile strain at 0.5 Hz and 10 % elongation for 30 min to simulate excessive mechanical loading in OA. In vivo experiments involved mice undergoing anterior cruciate ligament transection (ACLT) to model OA, followed by interventions on Rcn2 expression through adeno-associated virus (AAV) injection and tamoxifen-induced gene deletion. 10 μL AAV2/5 containing AAV-Rcn2 or AAV-shRcn2 was administered to the mice by articular injection at 1 week post ACLT surgery, and Col2a1-creERT: Rcn2 mice were injected with tamoxifen intraperitoneally to obtain Rcn2-conditional knockout mice. Finally, we explored the mechanism of Rcn2 affecting OA. Here, we identified reticulocalbin-2 (Rcn2) as a mechanosensitive factor in chondrocytes, which was significantly elevated in chondrocytes under mechanical overloading. PIEZO type mechanosensitive ion channel component 1 (Piezo1) is a critical mechanosensitive ion channel, which mediates the effect of mechanical loading on chondrocytes, and we found that increased Rcn2 could be suppressed through knocking down Piezo1 under excessive mechanical loading. Furthermore, chondrocyte-specific deletion of Rcn2 in adult mice alleviated OA progression in the mice receiving the surgery of ACLT. On the contrary, articular injection of Rcn2-expressing adeno-associated virus (AAV) accelerated the progression of ACLT-induced OA in mice. Mechanistically, Rcn2 accelerated the progression of OA through promoting the phosphorylation and nuclear translocation of signal transducer and activator of transcription 3 (Stat3).
关节软骨暴露于过度机械负荷与骨关节炎（OA）的发病机制密切相关。然而，过度机械负荷驱动 OA 的确切分子机制尚不清楚。在体外，原代软骨细胞在 0.5 Hz 和 10%伸长率下暴露于循环拉伸应变 30 分钟，以模拟 OA 中的过度机械负荷。体内实验涉及前交叉韧带切断（ACLT）的小鼠，以建立 OA 模型，然后通过腺相关病毒（AAV）注射和他莫昔芬诱导的基因缺失干预 Rcn2 的表达。在 ACLT 手术后 1 周，通过关节内注射向小鼠给予 10 μL AAV2/5 包含 AAV-Rcn2 或 AAV-shRcn2，并用他莫昔芬腹腔内注射 Col2a1-creERT:Rcn2 小鼠获得 Rcn2 条件性敲除小鼠。最后，我们探讨了 Rcn2 影响 OA 的机制。在这里，我们确定了网状钙结合蛋白-2（Rcn2）为软骨细胞中的机械敏感因子，其在机械超负荷下的软骨细胞中显著升高。PIEZO 型机械敏感离子通道成分 1（Piezo1）是一种关键的机械敏感离子通道，介导机械负荷对软骨细胞的影响，我们发现，在过度机械负荷下，通过敲低 Piezo1 可以抑制 Rcn2 的增加。此外，成年小鼠软骨细胞特异性敲除 Rcn2 可减轻接受 ACLT 手术小鼠的 OA 进展。相反，在关节内注射表达 Rcn2 的腺相关病毒（AAV）加速了 ACLT 诱导的 OA 在小鼠中的进展。从机制上讲，Rcn2 通过促进信号转导和转录激活因子 3（Stat3）的磷酸化和核易位来加速 OA 的进展。
