PGC1/PPAR Drive Cardiomyocyte Maturation through Regulation of Yap1 and SF3B2

Abstract

Cardiomyocytes undergo significant levels of structural and functional changes after birth-fundamental processes essential for the heart to produce the volume and contractility to pump blood to the growing body. However, due to the challenges in isolating single postnatal/adult myocytes, how individual newborn cardiomyocytes acquire multiple aspects of mature phenotypes remains poorly understood. Here we implemented large-particle sorting and analyzed single myocytes from neonatal to adult hearts. Early myocytes exhibited a wide-ranging transcriptomic and size heterogeneity, maintained until adulthood with a continuous transcriptomic shift. Gene regulatory network analysis followed by mosaic gene deletion revealed that peroxisome proliferator-activated receptor coactivator-1 signaling-activated in vivo but inactive in pluripotent stem cellderived cardiomyocytes-mediates the shift. The signaling regulated key aspects of cardiomyocyte maturation simultaneously through previously unrecognized regulators, including Yap1 and SF3B2. Our study provides a single-cell roadmap of heterogeneous transitions coupled to cellular features and unveils a multifaceted regulator controlling cardiomyocyte maturation. bioRxiv | February 6, 2020 1-16

Trajectory reconstruction identifies dysregulation of perinatal maturation programs in pluripotent stem cell-derived cardiomyocytes

“…To understand the gene expression changes over CM maturation at the single cell level, we performed trajectory reconstruction using Monocle 3 (23) ( Figure 1B, Supplementary Note 2 ). Monocle 3 recovered a unidirectional, non-branching trajectory, matching earlier reports (5, 11, 24). Trajectory reconstruction enables calculation of “pseudotime,” a metric of progression along an inferred biological process.…”

“…Many of the dysregulated maturation TFs were identified as being important regulators of in vivo CM maturation in our above analysis ( Figure 1K ). Additionally, almost all have been previously directly implicated in either CM differentiation, maturation, or disease response (11, 29–32, 45–51). The STRING protein database identified significant connectivity between these TFs ( Figure S4E ), with a protein-protein interaction enrichment p-value of 1.75 × 10 -8 .…”

“…We subsequently compared the establishment of gene regulatory networks (GRNs) between PSC-CMs and endogenous CMs. However, this work was done using bulk samples, while CM maturation occurs heterogeneously across time both in vivo and in vitro (5, 11), suggesting a need for further data.…”

Transcriptomic entropy benchmarks stem cell-derived cardiomyocyte maturation against endogenous tissue at single cell level

“…At the single cell level, CM maturation proceeds heterogeneously along a unidirectional trajectory (33). We were therefore curious to know the extent to which entropy score could capture single cell positioning along this trajectory, in effect functioning as a pseudotime metric.…”

hiPSC-Derived Cardiac Tissue for Disease Modeling and Drug Discovery

“…Such factors include the heterodimers formed by peroxisome proliferator-activated receptors (PPARs)/retinoid X receptors (RXRs) and estrogen-related receptors α, β, and γ (ERRs) [ 150 , 151 ]. Both PPARs and ERRs directly interact with PGC1α/β (PPARγ coactivator α/β), the master regulators of FAO and mitochondrial respiration [ 152 , 153 , 154 ].…”