Proteomic Analysis of Human Pluripotent Stem Cell-Derived, Fetal and Adult Ventricular Cardiomyocytes Reveals Pathways Crucial for Cardiac Metabolism and Maturation

Abstract

BACKGROUND: -Differentiation of pluripotent human embryonic stem cells (hESCs) to the cardiac lineage represents a potentially unlimited source of ventricular cardiomyocytes ( V: CMs), but hESC- V: CMs are developmentally immature. Previous attempts to profile hESC- V: CMs primarily relied on transcriptomic approaches, but the global proteome has not been examined. Furthermore, most hESC-CM studies focus on pathways important for cardiac differentiation, rather than regulatory mechanisms for CM maturation. We hypothesized that gene products and pathways crucial for maturation can be identified by comparing the proteomes of hESCs, hESC-derived V: CMs, human fetal (hF) and adult (hA) V: and atrial ( A: ) CMs. METHODS AND RESULTS: -Using 2D-Differential-In-Gel Electrophoresis (DIGE), 121 differentially expressed (>1.5-fold, p<0.05) proteins were detected. The dataset implicated a role of the peroxisome proliferator-activated receptor alpha (PPARA) signalling in cardiac maturation. Consistently, WY-14643, a PPARA agonist, increased fatty oxidative enzyme level, hyperpolarized mitochondrial membrane potential and induced a more organized morphology. Along this line, treatment with the thyroid hormone triiodothyronine (T3) increased the dynamic tension developed in engineered human ventricular cardiac microtissue (hvCMT) by 3-folds, signifying their maturation. CONCLUSIONS: -We conclude that the PPARA and thyroid hormone pathways modulate the metabolism and maturation of hESC- V: CMs and their engineered tissue constructs. These results may lead to mechanism-based methods for deriving mature chamber-specific CMs.