Takeuchi Shiho, Nakano Shin-Ichi, Nakamura Katsuyuki, Ozoe Atsufumi, Chien Peggie, Yoshihara Hidehito, Hakuno Fumihiko, Matsuwaki Takashi, Saeki Yasushi, Takahashi Shin-Ichiro, Yamanouchi Keitaro, Nishihara Masugi
Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Department of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Exp Cell Res. 2016 Oct 1;347(2):367-77. doi: 10.1016/j.yexcr.2016.08.023. Epub 2016 Aug 28.
Intramuscular adipose tissue and fibrous tissue are observed in some skeletal muscle pathologies such as Duchenne muscular dystrophy and sarcopenia, and affect muscle strength and myogenesis. They originate from common fibrogenic/adipogenic cells in the skeletal muscle. Thus, elucidating the regulatory mechanisms underlying fibrogenic/adipogenic cell differentiation is an important step toward the mediation of these disorders. Previously, we established a highly adipogenic progenitor clone, 2G11, from rat skeletal muscle and showed that basic fibroblast growth factor (bFGF) is pro-adipogenic in these cells. Here, we demonstrated that 2G11 cells give rise to fibroblasts upon transforming growth factor (TGF)-β1 stimulation, indicating that they possess mesenchymal progenitor cells (MPC)-like characteristics. The previously reported MPC marker PDGFRα is expressed in other cell populations. Accordingly, we produced monoclonal antibodies that specifically bind to 2G11 cell surface antigens and identified chondroitin sulfate proteoglycan 4 (CSPG4) as a potential MPC marker. Based on an RNA interference analysis, we found that CSPG4 is involved in both the pro-adipogenic effect of bFGF and in TGF-β-induced alpha smooth muscle actin expression and stress fiber formation. By establishing an additional marker for MPC detection and characterizing its role in fibrogenic/adipogenic differentiation, these results will facilitate the development of effective treatments for skeletal muscle pathologies.
在一些骨骼肌疾病如杜氏肌营养不良症和肌肉减少症中可观察到肌内脂肪组织和纤维组织，它们会影响肌肉力量和肌生成。它们起源于骨骼肌中常见的纤维生成/脂肪生成细胞。因此，阐明纤维生成/脂肪生成细胞分化的调控机制是调节这些疾病的重要一步。此前，我们从大鼠骨骼肌中建立了一个高度脂肪生成的祖细胞克隆2G11，并表明碱性成纤维细胞生长因子（bFGF）在这些细胞中具有促脂肪生成作用。在此，我们证明2G11细胞在转化生长因子（TGF）-β1刺激下可产生成纤维细胞，表明它们具有间充质祖细胞（MPC）样特征。先前报道的MPC标志物血小板衍生生长因子受体α（PDGFRα）在其他细胞群体中表达。因此，我们制备了特异性结合2G11细胞表面抗原的单克隆抗体，并鉴定硫酸软骨素蛋白聚糖4（CSPG4）为潜在的MPC标志物。基于RNA干扰分析，我们发现CSPG4既参与bFGF的促脂肪生成作用，也参与TGF-β诱导的α平滑肌肌动蛋白表达和应力纤维形成。通过建立用于MPC检测的额外标志物并表征其在纤维生成/脂肪生成分化中的作用，这些结果将有助于开发针对骨骼肌疾病的有效治疗方法。
