Department of Cellular and Molecular Medicine, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.
J Cell Mol Med. 2011 Jun;15(6):1379-92. doi: 10.1111/j.1582-4934.2011.01330.x.
Skeletal muscle interstitium is crucial for regulation of blood flow, passage of substances from capillaries to myocytes and muscle regeneration. We show here, probably, for the first time, the presence of telocytes (TCs), a peculiar type of interstitial (stromal) cells, in rat, mouse and human skeletal muscle. TC features include (as already described in other tissues) a small cell body and very long and thin cell prolongations-telopodes (Tps) with moniliform appearance, dichotomous branching and 3D-network distribution. Transmission electron microscopy (TEM) revealed close vicinity of Tps with nerve endings, capillaries, satellite cells and myocytes, suggesting a TC role in intercellular signalling (via shed vesicles or exosomes). In situ immunolabelling showed that skeletal muscle TCs express c-kit, caveolin-1 and secrete VEGF. The same phenotypic profile was demonstrated in cell cultures. These markers and TEM data differentiate TCs from both satellite cells (e.g. TCs are Pax7 negative) and fibroblasts (which are c-kit negative). We also described non-satellite (resident) progenitor cell niche. In culture, TCs (but not satellite cells) emerge from muscle explants and form networks suggesting a key role in muscle regeneration and repair, at least after trauma.
骨骼肌间质对于调节血液流动、毛细血管物质向肌细胞的传递以及肌肉再生至关重要。我们在这里首次展示了，在大鼠、小鼠和人类骨骼肌中存在着一种特殊的间质（基质）细胞—— 间质细胞（TCs）。TC 的特征包括（如在其他组织中已经描述过的）小细胞体和非常长而细的细胞突起——telopodes（Tps），呈念珠状、二叉分枝和 3D 网络分布。透射电子显微镜（TEM）显示 Tps 与神经末梢、毛细血管、卫星细胞和肌细胞非常接近，这表明 TCs 在细胞间信号传递（通过脱落小泡或外泌体）中发挥作用。原位免疫标记显示，骨骼肌 TCs 表达 c-kit、 caveolin-1 并分泌 VEGF。细胞培养也证明了相同的表型特征。这些标志物和 TEM 数据将 TCs 与卫星细胞（例如 TCs 为 Pax7 阴性）和成纤维细胞（c-kit 阴性）区分开来。我们还描述了非卫星（固有）祖细胞龛。在培养中，TCs（而非卫星细胞）从肌肉外植体中出现并形成网络，这表明它们在肌肉再生和修复中至少在创伤后起着关键作用。
