Geometric control of muscle stem cell self-renewal

成人骨骼肌组织包含常驻干细胞，称为卫星细胞，它们存在于一个专门的位置(利基)，并在一生中保持组织的完整性。我们对卫星细胞调节的生物化学信号，如生长因子、细胞因子和受体配体的理解，过去和现在都是由加拿大研究人员的优雅研究推动的。包括生物力学(僵硬)、建筑和地形在内的生物物理生态位线索对成体干细胞调节的影响正在得到重视，但在很大程度上仍未被探索。我们先前的工作揭示了底物硬度对卫星细胞行为和命运的深刻影响。将小鼠卫星细胞培养在与骨骼肌柔软匹配的合成生物材料(仿生)上，与传统的刚性塑料培养相比，显示出更高的存活率和更多的干细胞(自我更新)。在这里，我们将结合严格的干细胞生物学、生物材料、计算机科学和显微镜方法来评估三维(3D)结构对肌肉干细胞调节的影响，三维(3D)结构是利基的第二个生物物理特征。生态位架构对卫星细胞形态施加几何限制，我们将利用这一新的观察结果(1)阐明通过2D仿生底物和通过工程(2)2D生态位“架构阵列”来指导成年干细胞命运的卫星细胞调控的细胞和分子机制；以及(3)3D生态位架构模型以系统地评估3D卫星细胞的调控。除了基础知识外，我们的研究还将提供新的发现工具：识别培养中自我更新事件的指标，诱导所需卫星细胞命运的培养平台，以及成人骨骼肌组织的3D模型。我们的综合方法为吸引和培训未来的学术界、医学界和生物技术领导者提供了一个理想的环境；这是一个核心优先事项。我们的研究计划确保商业化机会和高素质的人员作为加拿大的可交付利益。

Adult skeletal muscle tissue contains resident stem cells, termed satellite cells, which exist in a specialized location (niche) and maintain tissue integrity throughout life. Our understanding of satellite cell regulation by biochemical niche cues such as growth factors, cytokines and receptor ligands was and continues to be advanced by the elegant studies of Canadian researchers. The influence of biophysical niche cues including biomechanics (stiffness), architecture and topography on adult stem cell regulation is gaining appreciation, but remains largely unexplored. Our prior work revealed the profound impact of substrate stiffness on satellite cell behavior and fate. Murine satellite cells cultured on a synthetic biomaterial matching the softness of skeletal muscle (biomimetic) exhibited improved survival and generated more stem cells (self-renewed) compared with culture on traditional rigid plastic. Here we will integrate rigorous stem cell biology, biomaterials, computer science, and microscopy approaches to evaluate the influence of three-dimensional (3D) architecture, a second biophysical feature of the niche, on muscle stem cell regulation. Niche architecture imposes geometric constraints on satellite cell morphology and we will leverage this novel observation (1) to elucidate cellular and molecular mechanisms underlying satellite cell regulation by 2D biomimetic substrates and by engineering (2) 2D niche 'architecture arrays' to direct adult stem cell fate; and (3) 3D niche architecture models to systematically evaluate satellite cell regulation in 3D. Our studies will deliver novel tools for discovery in addition to fundamental knowledge: a metric to identify self-renewal events in culture, a culture platform to induce desired satellite cell fates and a 3D model of adult skeletal muscle tissue. Our integrative approach provides an ideal setting to engage and train future leaders of academia, medicine and biotech; a central priority. Our Research Program ensures commercialization opportunities and highly qualified personnel as deliverable benefits to Canada.