Volumetric muscle loss (VML) occurs when skeletal muscle injury is too large for the body to fully self-repair. Typically, fibrotic tissue fills the void, which reduces muscle functionality and limb movement. Although a wide variety of natural and synthetic scaffolds have been studied with the purpose of providing the appropriate structural support, to date no scaffold has significantly restored muscle functionality after VML. Satellite cells, adult stem cells within the muscle capable of restoring smaller injuries, are sensitive to the stiffness and composition of the surrounding environment. Scaffolds that only address structural support are not sufficient to restore functionality and instead need to be designed to both promote satellite cell activation and prevent excessive fibroblast recruitment. The objective of this study was to design a scaffold that mimicked the regenerative environment and determine how the biomechanical properties differentially influence myogenic precursor and connective tissue cells. One of the main extracellular matrix (ECM) molecules upregulated during regeneration is hyaluronic acid (HA). Therefore, thiol-modified HA and poly(ethylene glycol) diacrylate hydrogels were generated and functionalized with peptides based on ECM known to influence regeneration, including fibronectin, laminin and tenascin-C. Scaffolds with different stiffness were created by varying HA content. The influence of HA stiffness and peptide functionalization on myogenic precursor and connective tissue cell proliferation, migration and gene expression was quantified. Our results indicated that HA hydrogels functionalized with the laminin peptide, IKVAV, show potential due to the enhanced promotion of myogenic cell behaviors including migration, proliferation and an increase in relevant transcription factors. STATEMENT OF SIGNIFICANCE: The goal of this study was to identify hyaluronic acid (HA) hydrogels with peptide and stiffness combinations that will direct muscle-derived cells towards regenerating phenotypes. While the interaction of skeletal muscle with RGD-functionalized HA hydrogels has been investigated, none of the other peptides described in this study had been used in the context of HA-based scaffolds and skeletal muscle-derived cells. Notably, the response of cells to variations in mechanics was dependent on ECM coating and lineage. The 3% HA functionalized with the laminin peptide, IKVAV, showed the most promise for future in vivo studies, as these hydrogels best promoted myoblast cell proliferation, attachment and spreading, enhanced migration over connective tissue cells and upregulated transcription factors associated with activated satellite cells.

中文翻译：

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透明质酸水凝胶与ECM衍生肽的功能化，以控制成肌细胞的行为。

当骨骼肌损伤太大而无法完全自我修复时，就会发生体积性肌肉丢失（VML）。典型地，纤维化组织填充了空隙，这降低了肌肉功能和四肢运动。尽管已经研究了各种各样的天然和合成支架以提供适当的结构支持，但是迄今为止，没有支架在VML后能显着恢复肌肉功能。卫星细胞是肌肉中能够恢复较小损伤的成年干细胞，对周围环境的僵硬和组成敏感。仅解决结构支持的支架不足以恢复功能，而是需要设计为既促进卫星细胞活化又防止过度的成纤维细胞募集。这项研究的目的是设计一种模仿再生环境的支架，并确定生物力学特性如何差异性地影响成肌前体细胞和结缔组织细胞。再生过程中上调的主要细胞外基质（ECM）分子之一是透明质酸（HA）。因此，基于已知影响再生的ECM肽（包括纤连蛋白，层粘连蛋白和肌腱蛋白-C）生成并巯基修饰了巯基修饰的HA和聚乙二醇（二甘醇）二丙烯酸酯水凝胶。通过改变HA的含量来创建具有不同刚度的脚手架。定量HA刚度和肽功能化对成肌前体和结缔组织细胞增殖，迁移和基因表达的影响。我们的结果表明，用层粘连蛋白肽IKVAV功能化的HA水凝胶显示出潜力，原因是肌原细胞行为的增强促进，包括迁移，增殖和相关转录因子的增加。重要性声明：这项研究的目的是鉴定具有肽和刚度组合的透明质酸（HA）水凝胶，这些水凝胶将指导肌肉来源的细胞趋向再生表型。虽然已经研究了骨骼肌与RGD官能化的HA水凝胶的相互作用，但本研究中描述的其他肽均未用于基于HA的支架和骨骼肌衍生的细胞。值得注意的是，细胞对力学变化的反应取决于ECM涂层和谱系。用层粘连蛋白肽IKVAV功能化的3％HA