Effect and Mechanism of Mechanical Stretch on Maturation of Induced Pluripotent Stem Cell Derived Cardiomyocytes

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were obtained using standard chemical definitions and small molecule induction protocol (CDM3), and further mechanical stretching was applied to them to explore the effect of mechanical stretch on hiPSC-CMs maturation and the potential mechanism. After recovery, culture, and identification of hiPSCs, hiPSCs were inoculated on traditional culture dishes covered with matrigel. After 24 h, the cell growth was observed by DAPI fluorescence under a fluorescence microscope, and dry identification of hiPSCs was performed by octamer-binding transcription factor 4 (OCT4) fluorescence. CDM3 differentiation medium was replaced when the cell connexion reached 80%. After 6 days of differentiation, hiPSC-CMs obtained were divided into control group and mechanical stretch group. After the stretching, PIEZO1 fluorescence was used to investigate the potential mechanism of PIEZO1 fluorescence. The growth of the cells was observed by DAPI fluorescence under a fluorescence microscope. The hiPSC-CMs myocardial markers were identified by cardiac troponin T (cTnT) and Myosin Light Chain 2 V (MLC2V) fluorescence. The immunofluorescence showed that the expressions of cTnT and MLC2V in mechanical stretch group were higher than those in control group ( P <0.05). Interestingly, the fluorescence expression of PIEZO1 protein was increased in the mechanical stretch group ( P <0.05). Mechanical extension may stimulate the maturation of human induced pluripotent stem cell-derived cardiomyocytes by facilitating the increased expression of the protein PIEZO1.