Skillin Nathaniel P, Kirkpatrick Bruce E, Herbert Katie M, Nelson Benjamin R, Hach Grace K, Günay Kemal Arda, Khan Ryan M, DelRio Frank W, White Timothy J, Anseth Kristi S
Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80303, USA.
The BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, 80303, USA.
bioRxiv. 2023 Aug 11:2023.08.08.552197. doi: 10.1101/2023.08.08.552197.
In skeletal muscle tissue, injury-related changes in stiffness activate muscle stem cells through mechanosensitive signaling pathways. Functional muscle tissue regeneration also requires the effective coordination of myoblast proliferation, migration, polarization, differentiation, and fusion across multiple length scales. Here, we demonstrate that substrate stiffness anisotropy coordinates contractility-driven collective cellular dynamics resulting in C2C12 myotube alignment over millimeter-scale distances. When cultured on mechanically liquid crystalline polymer networks (LCNs) lacking topographic features that could confer contact guidance, C2C12 myoblasts collectively polarize in the stiffest direction of the substrate. Cellular coordination is amplified through reciprocal cell-ECM dynamics that emerge during fusion, driving global myotube-ECM ordering. Conversely, myotube alignment was restricted to small local domains with no directional preference on mechanically LCNs of same chemical formulation. These findings reveal a role for stiffness anisotropy in coordinating emergent collective cellular dynamics, with implications for understanding skeletal muscle tissue development and regeneration.
在骨骼肌组织中，与损伤相关的硬度变化通过机械敏感信号通路激活肌肉干细胞。功能性肌肉组织再生还需要成肌细胞在多个长度尺度上的增殖、迁移、极化、分化和融合的有效协调。在这里，我们证明底物硬度各向异性协调收缩驱动的集体细胞动力学，导致C2C12肌管在毫米尺度距离上排列。当在缺乏可提供接触导向的地形特征的机械液晶聚合物网络（LCNs）上培养时，C2C12成肌细胞在底物最硬的方向上集体极化。细胞协调通过融合过程中出现的相互细胞-细胞外基质动力学得到放大，驱动全局肌管-细胞外基质有序排列。相反，在相同化学配方的机械LCNs上，肌管排列局限于小的局部区域，没有方向偏好。这些发现揭示了硬度各向异性在协调新兴集体细胞动力学中的作用，对理解骨骼肌组织发育和再生具有重要意义。
