The First Affiliated Hospital, Chongqing Medical University, Chongqing, China.
Department of Orthopaedic Surgery, the Second Affiliated Hospital, Chongqing Medical University, Chongqing, China.
Int J Med Sci. 2020 Jul 2;17(12):1692-1703. doi: 10.7150/ijms.45786. eCollection 2020.
Reconstruction of bone defects is one of the most substantial and difficult clinical challenges in orthopedics. Transforming growth factor beta 1 (TGFβ1) might play an important role in stimulating osteogenic differentiation of bone morphogenetic protein 9 (BMP9)-induced C3H10T1/2 mesenchymal stem cells. In our current study, we examined the potential synergy between TGFβ1 and BMP9 in promoting the osteogenesis of C3H10T1/2 cells, and whether such effects could contribute to bone formation . Our experiment data indicated that TGFβ1 could increase the expression of osteogenic markers and the formation of mineralized calcium nodules in, while suppressing the proliferation of, BMP9-induced C3H10T1/2 cells. Furthermore, mice intramuscularly injected with BMP9/TGFβ1-transduced C3H10T1/2 cells into the gastrocnemius muscle on their tibiae developed ectopic bone masses with more mature osteoid structures, compared to those grafted with cells expressing BMP9/RFP. Subsequent mechanistic studies found that TGFβ1-induced enhancement of osteogenesis in BMP9-overexpressing C3H10T1/2 cells was accompanied by augmented expression of heat shock protein 47 (HSP47), a collagen-specific molecular chaperone essential for collagen biosynthesis, and can be attenuated by pirfenidone, a known anti-fibrotic inhibitor. Interestingly, protein microarray analysis suggested that TGFβ1/BMP9-dependent osteogenesis of C3H10T1/2 cells seemed to involve several non-canonical signaling pathways such as Janus kinase-signal transducer and activator of transcription, phosphoinositide-3-kinase-protein kinase B, and mitogen-activated protein kinase. These results provided further evidence that TGFβ1 could promote bone formation from BMP9-induced C3H10T1/2 cells and shed important light on the underlying molecular mechanisms.
骨缺损的重建是骨科领域最具挑战性和困难的临床问题之一。转化生长因子β 1（TGFβ1）可能在刺激骨形态发生蛋白 9（BMP9）诱导的 C3H10T1/2 间充质干细胞成骨分化中发挥重要作用。在本研究中，我们研究了 TGFβ1 与 BMP9 之间在促进 C3H10T1/2 细胞成骨方面的潜在协同作用，以及这种作用是否有助于骨形成。我们的实验数据表明，TGFβ1 可以增加成骨标志物的表达和矿化钙结节的形成，同时抑制 BMP9 诱导的 C3H10T1/2 细胞的增殖。此外，将 BMP9/TGFβ1 转导的 C3H10T1/2 细胞注射到小鼠胫骨的比目鱼肌中，与转导 BMP9/RFP 的细胞相比，在胫骨中形成了具有更成熟骨样结构的异位骨块。随后的机制研究发现，TGFβ1 诱导的 BMP9 过表达 C3H10T1/2 细胞中的成骨增强伴随着热休克蛋白 47（HSP47）的表达增加，HSP47 是胶原生物合成所必需的胶原特异性分子伴侣，可被已知的抗纤维化抑制剂吡非尼酮减弱。有趣的是，蛋白质微阵列分析表明，TGFβ1/BMP9 依赖的 C3H10T1/2 细胞成骨似乎涉及几种非经典信号通路，如 Janus 激酶-信号转导和转录激活因子、磷酸肌醇 3-激酶-蛋白激酶 B 和丝裂原激活蛋白激酶。这些结果进一步证明 TGFβ1 可以促进 BMP9 诱导的 C3H10T1/2 细胞的骨形成，并为潜在的分子机制提供了重要线索。
