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.

中文翻译：

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骨骼肌间充质祖细胞向肌成纤维细胞的分化是可逆的。

肌内脂肪组织（IMAT）的积累和胶原蛋白积累引起的纤维组织的发育都会影响肉质，如嫩度、质地和风味。因此，调节骨骼肌中脂肪和纤维组织的数量对于生产优质肉类非常重要。IMAT 由脂肪细胞组成，而纤维组织中的胶原蛋白主要由活化的成纤维细胞产生。脂肪细胞和成纤维细胞都从它们的共同祖先分化而来，称为间充质祖细胞 (MPC)。我们之前建立了大鼠 MPC 克隆，2G11 细胞。由于几份报告涉及成纤维细胞分化的可塑性，在本研究中，使用 2G11 细胞，我们询问从 MPC 分化的肌成纤维细胞是否能够在体外重新获得脂肪形成潜力。通过用 bFGF 处理，它们的 αSMA 表达降低，脂肪形成潜力部分恢复。此外，通过降低细胞密度和 bFGF 处理，2G11 细胞来源的肌成纤维细胞失去了 αSMA 表达并显示出最高的脂肪形成潜力，这伴随着它们从扁平状到纺锤状的形态变化，这通常是用 MPC 观察到的。这些结果表明，MPC 衍生的肌成纤维细胞可以重新获得脂肪形成潜力，这可能是通过返回到未分化的 MPC 样状态来介导的。这伴随着它们从扁平状到纺锤状的形态变化，这通常是用 MPC 观察到的。这些结果表明，MPC 衍生的肌成纤维细胞可以重新获得脂肪形成潜力，这可能是通过返回到未分化的 MPC 样状态来介导的。这伴随着它们从扁平状到纺锤状的形态变化，这通常是用 MPC 观察到的。这些结果表明，MPC 衍生的肌成纤维细胞可以重新获得脂肪形成潜力，这可能是通过返回到未分化的 MPC 样状态来介导的。