Institute of Biomedical Engineering, University of Toronto, Toronto, ON, M5S 3E2, Canada.
Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada.
J Cell Sci. 2024 Mar 15;137(6). doi: 10.1242/jcs.261666. Epub 2024 Mar 27.
Understanding how biophysical and biochemical microenvironmental cues together influence the regenerative activities of muscle stem cells and their progeny is crucial in strategizing remedies for pathological dysregulation of these cues in aging and disease. In this study, we investigated the cell-level influences of extracellular matrix (ECM) ligands and culture substrate stiffness on primary human myoblast contractility and proliferation within 16 h of plating and found that tethered fibronectin led to stronger stiffness-dependent responses compared to laminin and collagen. A proteome-wide analysis further uncovered cell metabolism, cytoskeletal and nuclear component regulation distinctions between cells cultured on soft and stiff substrates. Interestingly, we found that softer substrates increased the incidence of myoblasts with a wrinkled nucleus, and that the extent of wrinkling could predict Ki67 (also known as MKI67) expression. Nuclear wrinkling and Ki67 expression could be controlled by pharmacological manipulation of cellular contractility, offering a potential cellular mechanism. These results provide new insights into the regulation of human myoblast stiffness-dependent contractility response by ECM ligands and highlight a link between myoblast contractility and proliferation.
了解生物物理和生化微环境线索如何共同影响肌肉干细胞及其后代的再生活动，对于制定策略来治疗衰老和疾病中这些线索的病理性失调至关重要。在这项研究中，我们研究了细胞外基质（ECM）配体和培养基板硬度对原代人成肌细胞在接种后 16 小时内的收缩性和增殖的细胞水平影响，发现与层粘连蛋白和胶原蛋白相比，固定化纤连蛋白导致更强的依赖于硬度的反应。蛋白质组学分析还揭示了在软质和硬质基质上培养的细胞之间的细胞代谢、细胞骨架和核成分调节差异。有趣的是，我们发现较软的基质增加了具有皱缩核的成肌细胞的发生率，并且皱缩的程度可以预测 Ki67（也称为 MKI67）的表达。核皱缩和 Ki67 表达可以通过细胞收缩性的药物处理来控制，提供了一种潜在的细胞机制。这些结果为 ECM 配体调节人成肌细胞硬度依赖性收缩反应提供了新的见解，并强调了成肌细胞收缩性和增殖之间的联系。
