Hazeltine Laurie B, Simmons Chelsey S, Salick Max R, Lian Xiaojun, Badur Mehmet G, Han Wenqing, Delgado Stephanie M, Wakatsuki Tetsuro, Crone Wendy C, Pruitt Beth L, Palecek Sean P
Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706, USA.
Int J Cell Biol. 2012;2012:508294. doi: 10.1155/2012/508294. Epub 2012 May 9.
Human pluripotent stem cell (hPSC-) derived cardiomyocytes have potential applications in drug discovery, toxicity testing, developmental studies, and regenerative medicine. Before these cells can be reliably utilized, characterization of their functionality is required to establish their similarity to native cardiomyocytes. We tracked fluorescent beads embedded in 4.4-99.7 kPa polyacrylamide hydrogels beneath contracting neonatal rat cardiomyocytes and cardiomyocytes generated from hPSCs via growth-factor-induced directed differentiation to measure contractile output in response to changes in substrate mechanics. Contraction stress was determined using traction force microscopy, and morphology was characterized by immunocytochemistry for α-actinin and subsequent image analysis. We found that contraction stress of all types of cardiomyocytes increased with substrate stiffness. This effect was not linked to beating rate or morphology. We demonstrated that hPSC-derived cardiomyocyte contractility responded appropriately to isoprenaline and remained stable in culture over a period of 2 months. This study demonstrates that hPSC-derived cardiomyocytes have appropriate functional responses to substrate stiffness and to a pharmaceutical agent, which motivates their use in further applications such as drug evaluation and cardiac therapies.
人多能干细胞（hPSC）衍生的心肌细胞在药物发现、毒性测试、发育研究和再生医学中具有潜在应用。在能够可靠地利用这些细胞之前，需要对其功能进行表征，以确定它们与天然心肌细胞的相似性。我们追踪了嵌入4.4 - 99.7kPa聚丙烯酰胺水凝胶中的荧光珠，该水凝胶位于收缩的新生大鼠心肌细胞和通过生长因子诱导定向分化从hPSC产生的心肌细胞下方，以测量响应底物力学变化的收缩输出。使用牵引力显微镜确定收缩应力，并通过α - 肌动蛋白的免疫细胞化学和随后的图像分析来表征形态。我们发现，所有类型的心肌细胞的收缩应力都随着底物硬度的增加而增加。这种效应与跳动频率或形态无关。我们证明，hPSC衍生的心肌细胞收缩性对异丙肾上腺素反应适当，并且在培养2个月期间保持稳定。这项研究表明，hPSC衍生的心肌细胞对底物硬度和药物制剂具有适当的功能反应，这促使它们在药物评估和心脏治疗等进一步应用中得到使用。
