National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China.
Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.
IUBMB Life. 2022 Nov;74(11):1081-1093. doi: 10.1002/iub.2670. Epub 2022 Aug 27.
Traumatic heterotopic ossification (HO) refers to the abnormal ectopic osteogenesis following trauma, causing limb dysfunction and seriously lowering the life quality of patients. Aberrant osteogenic behavior of progenitor cells that ectopically accumulated within the soft tissues are believed to be responsible for HO formation. However, the detailed mechanism still remained to be clarified. Here in this study, we successfully isolated osteoprogenitors from human heterotopic ossification tissues (HO-ops) and identified their stemness and multi-directional differentiation potential. Using alkaline phosphatase staining together with alizarin red staining, we confirmed that the HO-ops in the heterotopic ossified tissues gained greater osteogenic potential than the normal human bone marrow mesenchymal stem cells (HBMSCs). RT-qPCR also indicated that HO-ops obtained more gene transcriptions of critical osteogenic determinators than HBMSCs. In addition, through Western blot, we proved that ERK signaling pathway and hedgehog signaling pathway were significantly activated in the HO-ops. When U0126 and cyclopamine were used to inhibit ERK signaling and hedgehog signaling respectively, the osteogenic potential of HO-ops decreased significantly. The hedgehog signaling and ERK signaling also showed cross-talk in HO-ops during osteogenic differentiation in HO-ops during osteogenic differentiation. The elevated ERK signaling and hedgehog signaling were further confirmed in the human traumatic HO sample sections by immunohistochemical staining. In sum, our results showed that the activation of ERK and hedgehog signaling pathway jointly enhanced the osteogenic potential of HO-ops to induce the formation of traumatic HO, which provides novel insights into the molecular basis of HO formation and offers promising targets for future therapeutic strategy.
创伤性异位骨化（HO）是指创伤后异常的异位成骨，导致肢体功能障碍，严重降低患者的生活质量。异常的祖细胞成骨行为被认为是异位积聚在软组织中导致 HO 形成的原因。然而，其详细机制仍有待阐明。在这项研究中，我们成功地从人类异位骨化组织（HO-ops）中分离出成骨前体细胞，并鉴定了它们的干性和多向分化潜能。通过碱性磷酸酶染色和茜素红染色，我们证实异位骨化组织中的 HO-ops 获得了比正常人骨髓间充质干细胞（HBMSCs）更强的成骨潜能。实时定量 PCR 也表明 HO-ops 获得了更多关键成骨决定因子的基因转录。此外，通过 Western blot，我们证明 ERK 信号通路和 Hedgehog 信号通路在 HO-ops 中被显著激活。当使用 U0126 和环巴胺分别抑制 ERK 信号通路和 Hedgehog 信号通路时，HO-ops 的成骨潜能显著降低。在 HO-ops 的成骨分化过程中，Hedgehog 信号通路和 ERK 信号通路也表现出交叉对话。免疫组织化学染色进一步证实了人类创伤性 HO 样本切片中升高的 ERK 信号通路和 Hedgehog 信号通路。总之，我们的研究结果表明，ERK 和 Hedgehog 信号通路的激活共同增强了 HO-ops 的成骨潜能，导致创伤性 HO 的形成，为 HO 形成的分子基础提供了新的见解，并为未来的治疗策略提供了有希望的靶点。
