Identification of Muscle-Derived Soluble and Mechanical Cues to Direct Differenti

描述（由申请人提供）：肌腱愈合能力差，断裂时需要用移植物进行手术修复。移植物充满了从失败到供体部位发病的问题，这促使了基于干细胞的组织工程策略用于组织替代。然而，细胞向肌腱谱系分化（肌腱发生）一直具有挑战性，部分原因是对肌腱发育的理解不足。发育生物学研究表明，肌肉在肌腱胚胎发生中起着重要的作用，尽管其贡献的机制还没有很好地理解，因为肌肉组织的相应物理（机械）和可溶性信号因子的影响在复杂的体内环境中一直难以研究。我们的目标是识别和表征肌细胞产生的可溶性和机械性腱生成线索，以指导腱生成。我们推测，肌肉细胞分泌的可溶性因子，作为其发育阶段的函数，将调节肌腱在体外的TPC，这一过程将通过动态机械刺激增强。使用一个独特的体外共培养系统，我们将表征肌肉细胞分泌的假定可溶性因子及其潜在的tenogenic作用（目的1），并研究潜在的机械负荷，以提高化学调节研究TGF 22作为一个模型可溶性因子（目的2）。这项研究的结果将随后在未来的研究中转化，通过控制这些影响的应用，开发基于间充质干细胞的再生策略。我们的长期目标是利用发育生物学作为动机和指导，开发基于间充质干细胞的新组织再生策略，以替代受伤或患病的肌腱和韧带。这项研究工作的结果将显着推进肌腱发育生物学的知识，有助于确定合理的可溶性因子剂量和机械负荷参数的祖细胞分化，并导致先进的策略，工程肌腱与间充质干细胞。

DESCRIPTION (provided by applicant): Tendons have poor healing ability and require surgical repair with grafts when ruptured. The grafts are fraught with problems ranging from failure to donor site morbidity, motivating stem cell-based tissue engineering strategies for tissue replacement. However, differentiation of cells toward the tendon lineage (tenogenesis) has been challenging due in part to a poor understanding of tendon development. Developmental biology studies have demonstrated that muscle plays a significant role in tendon embryogenesis, though the mechanisms of its contributions are not well understood because the respective physical (mechanical) and soluble signaling factor influences of muscle tissue have been difficult to study in a complex in vivo environment. Our objective is to identify and characterize muscle cell-produced soluble and mechanical tenogenic cues to direct tenogenesis. We hypothesize that soluble factors secreted by muscle cells, as a function of their developmental stage, will regulate tenogenesis of TPCs in vitro and that this process will be enhanced by dynamic mechanical stimulation. Using a unique in vitro co-culture system we will characterize muscle cell secretion of putative soluble factors and their potential tenogenic roles (Aim 1), and investigate the potential for mechanical loading to enhance chemoregulation by studying TGF22 as a model soluble factor (Aim 2). The outcomes of this study will subsequently be translated in a future study to develop a mesenchymal stem cell-based regeneration strategy through controlled application of these influences. Our long-range goal is to use developmental biology as motivation and a guide in developing novel mesenchymal stem cell-based strategies in regenerating new tissue to replace injured or diseased tendons and ligaments. The outcome of this research effort would significantly advance knowledge of tendon developmental biology, help define rational soluble factor dosing and mechanical loading parameters for progenitor cell differentiation, and lead to advanced strategies to engineer tendons with mesenchymal stem cells.