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Pluripotent Stem Cell Derived Cardiac Cells for Myocardial Repair
Published on: February 3, 2017
Follistatin From hiPSC-Cardiomyocytes Promotes Myocyte Proliferation in Pigs With Postinfarction LV Remodeling
Yuhua Wei1, Gregory Walcott1,2, Thanh Nguyen1
1Department of Biomedical Engineering, School of Medicine and School of Engineering, University of Alabama at Birmingham, Birmingham (Y.W., G.W., T.N., X.G., B.G., H.Z., A.G., M.R.-G., J.M.R., L.Y., J.Z.).
Background:
When human induced pluripotent stem cells (hiPSCs) that CCND2-OE (overexpressed cyclin-D2) were differentiated into cardiomyocytes (CCND2-OEhiPSC-CMs) and administered to the infarcted hearts of immunodeficient mice, the cells proliferated after administration and repopulated >50% of the scar. Here, we knocked out human leukocyte antigen class I and class II expression in CCND2-OEhiPSC-CMs (KO/OEhiPSC-CMs) to reduce the cells' immunogenicity and then assessed the therapeutic efficacy of KO/OEhiPSC-CMs for the treatment of myocardial infarction.
Methods:
KO/OEhiPSC-CM and wild-type hiPSC-CM (WThiPSC-CM) spheroids were differentiated in shaking flasks, purified, characterized, and intramyocardially injected into pigs after ischemia/reperfusion injury; control animals were injected with basal medium. Cardiac function was evaluated via cardiac magnetic resonance imaging, and cardiomyocyte proliferation was assessed via immunostaining and single-nucleus RNA sequencing.
Results:
Measurements of cardiac function and scar size were significantly better in pigs treated with KO/OEhiPSC-CM spheroids than in animals treated with medium or WThiPSC-CM spheroids. KO/OEhiPSC-CMs were detected for just 1 week after administration, but assessments of cell cycle activity and proliferation were significantly higher in the endogenous pig cardiomyocytes of the hearts from the KO/OEhiPSC-CM spheroid group than in those from the other 2 groups. Single-nucleus RNA-sequencing analysis identified a cluster of proliferating cardiomyocytes that was significantly more prevalent in the KO/OEhiPSC-CM spheroid-treated hearts (3.65%) than in the hearts from the medium (0.89%) or WThiPSC-CM spheroid (1.33%) groups at week 1. YAP (Yes-associated protein) protein levels and nuclear localization were also significantly upregulated in pig cardiomyocytes after treatment with KO/OEhiPSC-CM spheroids. Follistatin, which interacts with the HIPPO/YAP pathway, was significantly more abundant in the medium from KO/OEhiPSC-CM spheroids than WThiPSC-CM spheroids (30.29±2.39 versus 16.62±0.83 ng/mL, P=0.0056). Treatment with follistatin increased WThiPSC-CM cell counts by 28.3% over 16 days in culture and promoted cardiomyocyte proliferation in the infarcted hearts of adult mice.
Conclusions:
KO/OEhiPSC-CM spheroids significantly improved cardiac function and reduced infarct size in pig hearts after ischemia/reperfusion injury by secreting follistatin, which upregulated HIPPO/YAP signaling and proliferation in endogenous pig cardiomyocytes.

