Department of Bioengineering, University of California, San Diego. 2880 Torrey Pines Scenic Drive, La Jolla, CA 92037, USA.
Biomed Microdevices. 2013 Feb;15(1):161-9. doi: 10.1007/s10544-012-9709-9.
Myoblasts are precursor muscle cells that lie nascent to mature skeletal muscle. Once muscle is damaged, these cells migrate, fuse, and regenerate the muscle tissue. It is known that skeletal muscle can partially regenerate in vivo after muscle tissue damage. However, this regeneration does not always occur, especially in more severe injuries. Cellular therapy using tissue-engineering approaches has been shown to improve organ repair and function. To exploit potential benefits of using cell therapy as an avenue for skeletal muscle repair, it is important to understand the cellular dynamics underlying skeletal myocyte formation and growth. Cardiac fibroblasts have been shown to have a major influence on cardiomyocyte function, repair, and overall spatial distribution. However, little is known regarding fibroblasts' role on skeletal myocyte function. In this study, we utilized a reconfigurable co-culture device to understand the contact and paracrine effects of fibroblasts on skeletal myocyte alignment and differentiation using murine myoblast and fibroblast cell lines. We demonstrate that myotube alignment is increased by direct contact with fibroblasts, while myotube differentiation is reduced both in the gap and contact configurations with fibroblasts after 6 days of co-culture. Furthermore, neutralizing antibodies to FGF-2 can block these effects of fibroblasts on myotube differentiation and alignment. Finally, bi-directional signaling is critical to the observed myoblast-fibroblast interactions, since conditioned media could not reproduce the same effects observed in the gap configuration. These findings could have direct implications on cell therapies for repairing skeletal muscle, which have only utilized skeletal myoblasts or stem cell populations alone.
成肌细胞是存在于成熟骨骼肌中的前体细胞肌肉细胞。一旦肌肉受损，这些细胞就会迁移、融合并再生肌肉组织。已知，骨骼肌在肌肉组织损伤后可以在体内部分再生。然而，这种再生并不总是发生，尤其是在更严重的损伤中。使用组织工程方法的细胞疗法已被证明可以改善器官修复和功能。为了利用细胞疗法作为骨骼肌修复的途径的潜在益处，了解骨骼肌细胞形成和生长的细胞动力学非常重要。已经表明，心肌成纤维细胞对心肌细胞的功能、修复和整体空间分布有很大的影响。然而，对于成纤维细胞在骨骼肌细胞功能中的作用知之甚少。在这项研究中，我们利用可重构共培养装置来了解成纤维细胞对骨骼肌细胞排列和分化的接触和旁分泌作用，使用鼠源成肌细胞和成纤维细胞系。我们证明，成肌管的排列通过与成纤维细胞的直接接触而增加，而在共培养 6 天后，与成纤维细胞的间隙和接触配置中，成肌管的分化均减少。此外，中和 FGF-2 的抗体可以阻断成纤维细胞对成肌管分化和排列的这些影响。最后，双向信号对于观察到的成肌细胞和成纤维细胞相互作用至关重要，因为条件培养基无法再现间隙配置中观察到的相同效果。这些发现可能对骨骼肌修复的细胞疗法有直接影响，这些疗法仅使用骨骼肌成肌细胞或干细胞群体。
