Abstract We developed a new approach for combined analysis of calcium (Ca2+) handling and beating forces in contractile cardiomyocytes. We employed human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) from dilated cardiomyopathy (DCM) patients carrying an inherited mutation in the sarcomeric protein troponin T (TnT), and isogenic TnT-KO iPSC-CMs generated via CRISPR/Cas9 gene editing. In these cells, Ca2+ handling as well as beating forces and –rates using single-cell atomic force microscopy (AFM) were assessed. We report impaired Ca2+ handling and reduced contractile force in DCM iPSC-CMs compared to healthy WT controls. TnT-KO iPSC-CMs display no contractile force or Ca2+ transients but generate Ca2+ sparks. We apply our analysis strategy to Ca2+ traces and AFM deflection recordings to reveal maximum rising rate, decay time, and duration of contraction with a multi-step background correction. Our method provides adaptive computing of signal peaks for different Ca2+ flux or force levels in iPSC-CMs, as well as analysis of Ca2+ sparks. Moreover, we report long-term measurements of contractile force dynamics on human iPSC-CMs. This approach enables deeper and more accurate profiling of disease-specific differences in cardiomyocyte contraction profiles using patient-derived iPSC-CMs.

中文翻译：

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人 iPSC 衍生心肌细胞中的综合 Ca2+ 通量和 AFM 力分析

摘要 我们开发了一种新方法，用于对收缩性心肌细胞中的钙 (Ca2+) 处理和搏动力进行组合分析。我们采用了来自扩张型心肌病 (DCM) 患者的人类诱导多能干细胞衍生心肌细胞 (iPSC-CMs)，这些患者携带肌节蛋白肌钙蛋白 T (TnT) 的遗传突变，以及通过 CRISPR/Cas9 基因产生的同基因 TnT-KO iPSC-CMs编辑。在这些细胞中，使用单细胞原子力显微镜 (AFM) 评估了 Ca2+ 处理以及搏动力和速率。我们报告了与健康的 WT 对照相比，DCM iPSC-CM 中 Ca2+ 处理受损和收缩力降低。TnT-KO iPSC-CM 不显示收缩力或 Ca2+ 瞬变，但会产生 Ca2+ 火花。我们将我们的分析策略应用于 Ca2+ 迹线和 AFM 偏转记录，以揭示最大上升速率、衰减时间、和多步背景校正的收缩持续时间。我们的方法提供了 iPSC-CM 中不同 Ca2+ 通量或力水平的信号峰值的自适应计算，以及 Ca2+ 火花的分析。此外，我们报告了人类 iPSC-CM 收缩力动力学的长期测量结果。这种方法可以使用源自患者的 iPSC-CM 更深入、更准确地分析心肌细胞收缩曲线中疾病特异性差异。