Retinoic acid modulation guides human-induced pluripotent stem cell differentiation towards left or right ventricle-like cardiomyocytes

Zhang, Hengliang (2024): Retinoic acid modulation guides human-induced pluripotent stem cell differentiation towards left or right ventricle-like cardiomyocytes. Dissertation, LMU München: Medizinische Fakultät

Abstract

Background: Cardiomyocytes (CMs) derived from human induced pluripotent stem cells (hiPSCs) by traditional methods are a mix of atrial and ventricular CMs and many other non-cardiomyocytes. Retinoic acid (RA) plays an important role in regulating the spatiotemporal development of the embryonic heart and high concentrations of RA have been shown to steer differentiation towards atrial CMs, whereas lower concentrations of RA promote a more ventricular-like CM profile. Aim: Create engineered heart tissue (EHT) with left and right ventricular phenotypes from hiPSCs by intervening with specific concentrations of retinoic acid (RA) during hiPSC differentiation towards CM. Methods: hiPSC were derived by reprogramming skin fibroblasts and erythroid progenitors. Different concentrations of RA (Control group without RA, LRA group with 0.05 µM and HRA group with 0.1 µM) were administered during the third to sixth days of the differentiation process. Engineered heart tissues (EHTs) were generated by assembling CMs derived from hiPSC (hiPSC-CM) at high cell density in a low collagen hydrogel. The maturation and growth of EHTs were induced in a customized biomimetic tissue culture system, that provides continuous electrical stimulation, medium agitation and stretch. The function of CMs and EHTs was analyzed under different conditions. Finally, RNA extraction and tissue fixation were performed on CMs and EHTs for RT-qPCR and immunofluorescence staining analysis. RNA sequencing was conducted on EHTs to examine how RA affects signaling involved in the function and structure of EHT Results: In the HRA group, hiPSC-CMs exhibited the first onset of beating and showed the highest expression of maturity genes MYH7 and cTnT. The expression of TBX5, NKX2.5 and CORIN, which are the marker genes for left ventricular CMs, was also the highest in the HRA group. The transcription factor MEF2C associated with RA, was highly expressed in the HRA group, while GATA4 was less expressed in the HRA group. In terms of EHT, the HRA group displayed the highest contraction force, the lowest beating frequency, and the highest sensitivity to hypoxia and isoprenaline, which means it was more functionally similar to the left ventricle. The expression of TBX5 and NKX2.5 was found to be the highest expression in the HRA group of EHT, while expression of TBX20 and ISL1 was found to be the highest expression in control group. When the electrical stimulation frequency of EHT in the HRA group was raised, it correspondingly increased its contractile force. The heightened contractility of EHT within the HRA group can be attributed to the promotion of augmented extracellular matrix strength by RA. Conclusion: By interfering with the differentiation process of hiPSC with a specific concentration of RA at a specific time, we were able to successfully induce CMs and EHT with a phenotype similar to that of the left ventricle or right ventricle. Our research paves the way for future studies on in vitro left ventricular or right ventricular function, personalized drug screening, and precision medicine.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Keywords: Retinoic acid, hiPSC, Cardiomyocyte, Engineered heart tissue, Left ventricle
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften ; 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• Fakultäten: Medizinische Fakultät
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 19. Juli 2024
• 1. Bericht­erstatter:in: Merkus, Daphne