Diversity Supplement for: Engineered Asymmetric Hydrogel for Muscle Stem Cell Polarity and Fate Specification

项目摘要 纤维脂肪生成祖细胞（FAP）是肌肉驻留的间充质基质细胞， 卫星细胞（MuSC）功能，包括活化、增殖和分化。与MuSC不同，这些细胞 存在于肌肉间质空间内，因此通过旁分泌因子与MuSC通信。在 在正常肌肉再生时，激活的FAP随着炎症消退和再生而经历凋亡。 收益。然而，在慢性肌肉损伤和疾病中，激活的FAP持续存在并分化为 肌成纤维细胞或脂肪细胞，其分别驱动纤维化和脂肪浸润。然而，到目前为止， 对FAP如何与其微环境相互作用以调节其激活的理解有限， 扩散和命运决定。在这个多样性补充应用程序中，我们将确定 FAP通过机械敏感性PIEZO 1离子通道响应被动和主动机械信号的作用。 这项研究通过揭示FAP如何整合，加强和扩大了父R 01项目的范围 来源于其合成生态位的生物物理信号，并提供额外的手段来控制MuSC极性， 细胞分裂在工程不对称生态位。为了实现这一目标，目标1将确定PIEZO 1如何调节 FAP的活化、增殖和分化。目标2将确定FAP中的PIEZO 1如何调节 细胞外基质硬度机械传感。目标3将确定FAP中的PIEZO 1如何调节响应度 拉伸加载和卸载。本研究的成果将进一步丰富对FAP的认识 生物学，确定药物靶点，以减轻骨骼肌损伤和疾病中的纤维化和脂肪浸润， 并告知用于扩增MuSC和/或生产FAP的离体FAP制造平台的设计 用于无细胞疗法的分泌蛋白质组。

PROJECT ABSTRACT Fibro-adipogenic progenitors (FAPs) are muscle-resident mesenchymal stromal cells that support muscle satellite cell (MuSC) function, including activation, proliferation, and differentiation. Unlike MuSCs, these cells reside within the muscle interstitial space and thus communicate with MuSCs through paracrine factors. In normal muscle regeneration, activated FAPs undergo apoptosis as the inflammation resolves and regeneration proceeds. However, in chronic muscle injuries and diseases, activated FAPs persist and differentiate into either myofibroblasts or adipocytes that drive fibrosis and fatty infiltration, respectively. However, to date, there is a limited understanding of how the FAPs interact with their microenvironment to regulate their activation, proliferation, and fate determination. In this Diversity Supplement application, we will determine the mechanistic role by which FAPs respond to passive and active mechanical signals via mechanosensitive PIEZO1 ion channel. This research strengthens and expands the scope of the parent R01 project by revealing how FAPs integrate biophysical signals derived from their synthetic niche and provide additional means to control MuSC polarity and cell divisions in the engineered asymmetric niche. Towards this goal, Aim 1 will determine how PIEZO1 regulates FAPs activation, proliferation, and differentiation. Aim 2 will determine how PIEZO1 in FAPs regulates extracellular matrix stiffness mechanosensing. Aim 3 will determine how PIEZO1 in FAPs regulates responsivity to tensile loading and unloading. The outcomes of this research will advance the current knowledge of FAPs biology, identify druggable targets to mitigate fibrosis and fatty infiltration in skeletal muscle injuries and diseases, and inform the design of ex vivo FAPs manufacturing platform for expanding MuSCs and/or producing FAPs secretome for acellular therapies.