Uncovering the influence of niche biomechanics on satellite stem cell fate

揭示生态位生物力学对卫星干细胞命运的影响

• 批准号: RGPIN-2019-07144
• 负责人: Gilbert, Penney
• 金额: $ 3.06万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=739331
• 关键词: Uncovering; influence; niche; biomechanics; satellite

A skeletal muscle contains aligned, cylindrical muscle fibres formed by the fusion of cells during development. Adult skeletal muscles possess self-healing properties due to a small number of tiny cells sprinkled within the tissue that sit atop each muscle fibre and are covered by a thin sheet of proteins known as the basement membrane. By virtue of this anatomical positioning, or niche, these `satellite' stem cells (SCs) reside in a three-dimensional environment where the protein milieu at their fibre and basement membrane surfaces are distinct. Ongoing studies by others show that the polarized nature of biomolecules in the SC niche is important for regulating their behavior. In parallel, our lab engages multidisciplinary collaborators to define and offer niche biomechanical stress as an additional polarized feature of the niche that, together with biomolecules, regulates SC behavior. Skeletal muscles move. We expect that when the muscle fibres contract and relax, that the fibre-associated surface of an SC experiences pushing and pulling forces. By virtue of the closely packed and aligned nature of muscle fibres, the basement membrane-associated surface of an SC is expected to experience squishing forces. We hypothesize that breaking this mechanical homeostasis, as would occur when a muscle is injured, is a direct and localized means to call SCs to reparative action by physically engaging cell surface proteins. In local and international collaborations and lab exchanges, our trainees will work closely with experts in biophysics, microscopy, FRET-based tension sensors, and membrane protein biology to test our hypothesis. We will quantify myogenic cell pulling forces in engineered two-dimensional culture microenvironments to define force generation maxima when the cells are unfettered by a third dimension. We will quantify the degree to which SCs are adhered to their niche and identify key membrane proteins contributing to this attachment. Lastly, we will demonstrate that breaking mechanical homeostasis in a living muscle tissue directly engages membrane proteins that push SCs out of slumber to begin repairing tissue damage. This research will advance fundamental knowledge about SC biology by gazing at the niche through a new lens. Our trainees will gain skillsets in the physics and mathematics of niche stresses, in hi-resolution microscopy, and in stem cell biology, while building a vast scientific network, and thereby poising them for careers in academia, medicine, or industry.

骨骼肌含有排列整齐的圆柱形肌肉纤维，由细胞在发育过程中融合而成。成人骨骼肌具有自我修复能力，因为少量微小细胞散布在组织中，位于每个肌肉纤维的顶部，并被一层被称为基底膜的薄层蛋白质覆盖。通过这种解剖定位，这些“卫星”干细胞(SCs)生活在三维环境中，其纤维和基底膜表面的蛋白质环境是不同的。其他人正在进行的研究表明，SC利基中生物分子的极化性质对于调节它们的行为很重要。同时，我们的实验室聘请了多学科的合作者来定义和提供利基生物力学应力，作为利基的一个额外的极化特征，与生物分子一起，调节SC的行为。骨骼肌会移动。我们预计，当肌肉纤维收缩和放松时，SC的纤维相关表面会经历推力和拉力。由于肌肉纤维紧密堆积和排列的特性，SC的基底膜相关表面预计会受到挤压。我们假设，当肌肉受伤时，打破这种机械动态平衡是一种直接和局部的方式，通过物理地与细胞表面蛋白接触来调用干细胞进行修复行动。在本地和国际合作和实验室交流中，我们的学员将与生物物理学、显微镜、基于FRET的张力传感器和膜蛋白生物学的专家密切合作，以验证我们的假设。我们将量化工程二维培养微环境中肌源性细胞的拉力，以确定当细胞不受第三维约束时产生的力量最大值。我们将量化干细胞在其利基上的附着程度，并确定有助于这种附着的关键膜蛋白。最后，我们将证明，在活的肌肉组织中，打破机械动态平衡直接与膜蛋白结合，将干细胞从睡眠中推出来，开始修复组织损伤。这项研究将通过一种新的视角凝视这一利基，从而推进关于SC生物学的基础知识。我们的受训人员将在小众压力的物理和数学、高分辨率显微镜和干细胞生物学方面获得技能，同时建立一个庞大的科学网络，从而为他们在学术界、医学或行业的职业生涯做好准备。