YAP dysregulation triggers hypertrophy by CCN2 secretion and TGFβ uptake in human pluripotent stem cell-derived cardiomyocytes
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ABSTRACT: Our research has demonstrated the following: (1) Confirmed that MYH7 mutations D239N, H251N, G256E lead to hypercontractility in hiPSC-derived cardiomyocytes (hiPSC-CMs); (2) Increase in YAP’s nuclear localization in both hiPSC-CMs and patient tissue with MYH7 HCM mutations; (3) A correlation between YAP's nuclear localization and enhanced force generation; (4) Nuclear deformation as a mechanism enabling YAP's nuclear entry and activation; (5) Transcriptomic changes resulting from positive and negative modifications in force generation; and (6) A distinctive paracrine hypertrophic signal reliant on cardiomyocyte-cardiac fibroblast crosstalk. Our unique insights to the intricacies of hypertrophic cardiomyopathy phenotypes hold the potential to provide mechanistic clarity, informing potential therapeutic strategies.
Project description:Background: Cardiomyocytes (CMs) induced 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 regulation of 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 phenotype from hiPSCs by intervening with specific concentrations of retinoic acid (RA) during hiPSC differentiation towards CM. Methods: hiPSC were derived by reprogramming skin fibroblasts. Different concentrations of RA (Control group without RA, LRA group with 0.05 µM and HRA group with 0.1 µM) were administered during 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-qPRC and immunofluorescence staining analysis. RNA sequencing was conducted on EHTs to examine how RA affects both 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 and ventricular development genes, NPPA and MYH7, were 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 paved the way for future studies on in vitro left ventricular or right ventricular function, personalized drug screening, and precision medicine.
Project description:ABSTRACT Background: Viral myocarditis is a life-threatening illness that may lead to heart failure or cardiac arrhythmias. This study examined whether human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) could be used to model the pathogenic processes of coxsackievirus-induced viral myocarditis and to screen antiviral therapeutics for efficacy. Methods and Results: Human iPSC-CMs were infected with a luciferase-expressing mutant of the coxsackievirus B3 strain (CVB3-Luc). Brightfield microscopy, immunofluorescence, and calcium imaging were used to characterize virally infected hiPSC-CMs. Viral proliferation on hiPSC-CMs was subsequently quantified using bioluminescence imaging. For drug screening, select antiviral compounds including interferon beta 1 (IFNβ1), ribavirin, pyrrolidine dithiocarbamate (PDTC), and fluoxetine were tested for their capacity to abrogate CVB3-Luc proliferation in hiPSC-CMs in vitro. The ability of some of these compounds to reduce CVB3-Luc proliferation in hiPSC-CMs was consistent with the reported drug effects in previous studies. Finally, mechanistic analyses via gene expression profiling of hiPSC-CMs infected with CVB3-Luc revealed an activation of viral RNA and protein clearance pathways within these hiPSC-CMs after IFNβ1 treatment. Conclusions: This study demonstrates that hiPSC-CMs express the coxsackievirus and adenovirus receptor, are susceptible to coxsackievirus infection, and can be used to confirm antiviral drug efficacy. Our results suggest that the hiPSC-CM/CVB3-Luc assay is a sensitive platform that could be used to screen novel antiviral therapeutics for their effectiveness in a high-throughput fashion. For this experiment, human induced pluripotent stem cell derived cardiomyocytes were infected with coxsackievirus at multiplicity of infection (MOI) of 5 for 8 hours. Cells were treated with and without interferon beta 1 in order to determine if treatment activates antiviral response genes and/or viral clearance pathways. 4 total samples (2 for each condition) were analyzed
Project description:Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have wide potential application in basic research, drug discovery, and regenerative medicine, but functional maturation remains challenging. Here, we present a simple method whereby maturation of hiPSC-CMs can be accelerated by simultaneous application of physiological Ca 2+ and frequency-ramped electrical pacing in culture. This combination produces realistic force-frequency relationship, physiological twitch kinetics, robust β-adrenergic response, improved Ca 2+ handling, and cardiac troponin I expression within 25 days. This study provides insights into the role of Ca 2+ in hiPSC-CM maturation and offers a scalable platform for translational and clinical research.
Project description:Human iPSC-derived cardiomyocytes (hiPSC-CMs) have proven invaluable for cardiac disease modeling and cardiac regeneration. Challenges with quality, inter-batch consistency, cryopreservation and scale remain, reducing experimental reproducibility and clinical translation. Here, we report a robust stirred suspension cardiac differentiation protocol with careful functional characterization of the resulting hiPSC-CMs. In a bioreactor, the protocol produced 1.2E6/mL hiPSC-CMs with ~94% purity from 14 iPSC lines. Bioreactor-differentiated CMs (bCMs) showed high viability after cryo-recovery (>90%) and predominantly ventricular identity. Compared to standard monolayer-differentiated CMs (mCMs), bCMs had greater reproducibility and more mature functional properties, including pacing capture to 4 Hz and greater force production in 3D engineered heart tissues. In more readily available magnetically stirred spinner flasks, the protocol yielded 1.8E6/mL spinner-differentiated CMs (sCMs) with 94% purity. Differentiation scaled readily in spinner flasks, as a 3.8-fold increase in cultured volume yielded 3.4E6/ml sCMs. sCMs had intermediate functional properties between mCMs and bCMs. Minor protocol modifications generated the first bioreactor-derived cardiac organoids (bCOs) fully generated in suspension. These reproducible, scalable, and resource efficient approaches to generate cardiac cells and organoids with well-characterized properties will expand the applications of hiPSC-CMs.
Project description:Anesthetic management of heart failure patients undergoing noncardiac surgery remains challenging due to cardiac suppressive properties of anesthetics. Due to varying electrophysiological properties, small and large animals are not good models for studying human myocardial anesthetic responses. Here we use hypertrophic (HCM), dilated (DCM) and healthy human induced pluripotent stem cells derived cardiomyocytes (hiPSC-CMs) to evaluate the cardiac suppression of propofol and etomidate. We demonstrate that propofol and etomidate act through GABAA receptors and contractile inhibition can occur without cell-cell junction. At supraphysiological dosage (100mM), we discovered that cardiac suppression induced by etomidate is reversible while propofol is not. Using transcriptome profiling, we uncover that etomidate was capable of inducing autophagy, likely through induction of cytosolic calcium. Lack of autophagy induction in propofol treated cardiomyocytes were associated with increased apoptosis. Together, we provide the robustness of using hiPSC-CMs as an in vitro cardiotoxicity platform for anesthetics. To delineate how etomidate confers cardioprotection during contraction inhibition, we performed transcriptome profiling on DCM hiPSC-CMs treated with either 10 μM propofol, 10 μM etomidate or DMSO control.
Project description:Embryonic signaling pathways exert stage-specific effects during cardiac development, yet the precise cues for proliferation or maturation remain elusive. To address this, we utilized spontaneously beating human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) at day 12 of differentiation and performed a combinatory screen for various dosages of the glycogen synthase kinase-3 (GSK3) inhibitor CHIR99021 and Insulin for the analysis of cell cycle in hiPSC-CMs. Our combinatory screen for proliferation, subsequential downstream sarcomere development and RNA-seq analyses for Insulin/Akt and CHIR99021/Wnt demonstrate synergistic effects on proliferation of immature hiPSC-CMs. Conversely, removal of the Wnt and Insulin stimuli leads to rapid cell cycle exit and facilitates the terminal differentiation of immature hiPSC-CMs. Detailed characterization reveals that Wnt/CHIR99021, but not Insulin, regulates sarcomere homeostasis and architecture of immature hiPSC-CMs. Moreover, we further identify a temporal interplay between CHIR99021/Wnt via TCF and Insulin via FoxO signaling as regulators between proliferation and maturation in immature hiPSC-CMs. This work describes the cues that control proliferation versus terminal differentiation in functional immature hiPSC-CMs, and provides molecular mechanistic understanding between proliferation and maturation development of hiPSC-CMs.