Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
Anim Sci J. 2020 Jan-Dec;91(1):e13368. doi: 10.1111/asj.13368.
Accumulation of intramuscular adipose tissue (IMAT) and development of fibrous tissues due to accumulation of collagen both affect meat quality such as tenderness, texture, and flavor. Thus, it is important for the production of high-quality meat to regulate the amount of adipose and fibrous tissues in skeletal muscle. IMAT is comprised of adipocytes, while collagens included in fibrous tissues are mainly produced by activated fibroblasts. Both adipocytes and fibroblasts are differentiated from their common ancestors, called mesenchymal progenitor cells (MPC). We previously established rat MPC clone, 2G11 cells. As several reports implicated the plasticity of fibroblast differentiation, in the present study, using 2G11 cells, we asked whether myofibroblasts differentiated from MPC are capable of re-gaining adipogenic potential in vitro. By treating with bFGF, their αSMA expression was reduced and adipogenic potential was restored partially. Furthermore, by lowering cell density together with bFGF treatment, 2G11 cell-derived myofibroblasts lost αSMA expression and showed the highest adipogenic potential, and this was along with their morphological change from flattened- to spindle-like shape, which is typically observed with MPC. These results indicated that MPC-derived myofibroblasts could re-acquire adipogenic potential, possibly mediated through returning to an undifferentiated MPC-like state.
肌肉内脂肪组织（IMAT）的积累和胶原积累导致的纤维组织的发育都会影响肉质的嫩度、质地和风味等。因此，调节骨骼肌中脂肪和纤维组织的数量对于生产高质量的肉类非常重要。IMAT 由脂肪细胞组成，而纤维组织中包含的胶原主要由激活的成纤维细胞产生。脂肪细胞和成纤维细胞都由其共同的祖细胞，称为间充质祖细胞（MPC）分化而来。我们之前建立了大鼠 MPC 克隆 2G11 细胞。由于有几份报告暗示了成纤维细胞分化的可塑性，在本研究中，我们使用 2G11 细胞，询问了从 MPC 分化而来的肌成纤维细胞是否能够在体外重新获得脂肪生成潜能。通过用 bFGF 处理，它们的αSMA 表达减少，部分恢复了脂肪生成潜能。此外，通过降低细胞密度并结合 bFGF 处理，2G11 细胞衍生的肌成纤维细胞失去了αSMA 表达，并显示出最高的脂肪生成潜能，并且形态从扁平状转变为典型的 MPC 样梭形。这些结果表明，MPC 衍生的肌成纤维细胞可以重新获得脂肪生成潜能，可能是通过回到未分化的 MPC 样状态来介导的。
