Dataset Information

Genome-wide association mapping for cardiomyocyte ploidy identifies Shroom3 as responsible for hyperpolyploidy and ventricular dilation

ABSTRACT: Cardiomyocyte (CM) polyploidization has been associated with cardiac injury responses, including regeneration and heart failure. However, our understanding of the comprehensive mechanisms governing CM ploidy and its influence on heart physiology has been hindered by a lack of experimental tools. To address this issue and uncover novel genetic regulators, we surveyed CM ploidy across a new genetic resource known as the Hybrid Rat Diversity Panel and find significant variation in ploidy phenotypes across the panel. Using select rat strains with divergent displays of CM ploidy, we found that hyperpolyploidization (≥8N) positively correlates with various physiological parameters namely left ventricular dilation and reduced ejection fraction. Genome-wide association mapping identifies several loci significantly associated with frequency of hyperpolyploid CMs. Investigation of genes harboring damaging protein coding variants identified enrichment of cytoarchitectural genes, of which the ACTIN-binding protein, Shroom3, was found to be strongly and specifically expressed in CMs and harbor 7 damaging protein coding variants. Indeed, CM-specific deletion of Shroom3 increased hyperpolyploidization in adult mice, while also promoting left ventricular dilation and reducing cardiac function. Furthermore, functional characterization of single nucleotide variants resulting in amino acid changes within SHROOM3 confirmed two protein coding variants that disrupted SHROOM3-ACTIN interaction. This study elucidates the genetic determinants of CM ploidy phenotypes and solidifies a relationship between CM ploidy and left ventricular function. Importantly, CM intrinsic expression of at least one gene mapped in this study, Shroom3, is confirmed to regulate CM hyperpolyploidization and cardiac function.

ORGANISM(S): Rattus norvegicus

PROVIDER: GSE307551 | GEO | 2026/03/25

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Project description:Background: We had shown that cardiomyocytes (CMs) were more efficiently differentiated from human induced pluripotent stem cells (hiPSCs) when the hiPSCs were reprogrammed from cardiac fibroblasts rather than dermal fibroblasts or blood mononuclear cells. Here, we continued to investigate the relationship between somatic-cell lineage and hiPSC-CM production by comparing the yield and functional properties of CMs differentiated from iPSCs reprogrammed from human atrial or ventricular cardiac fibroblasts (AiPSC or ViPSC, respectively). Methods: Atrial and ventricular heart tissues were obtained from the same patient, reprogrammed into AiPSCs or ViPSCs, and then differentiated into CMs (AiPSC-CMs or ViPSC-CMs, respectively) via established protocols. Results: The time-course of expression for pluripotency genes (OCT4, NANOG, and SOX2), the early mesodermal marker Brachyury, the cardiac mesodermal markers MESP1 and Gata4, and the cardiovascular progenitor-cell transcription factor NKX2.5 were broadly similar in AiPSC-CMs and ViPSC-CMs during the differentiation protocol. Flow-cytometry analyses of cardiac troponin T expression also indicated that purity of the two differentiated hiPSC-CM populations (AiPSC-CMs: 88.23±4.69%, ViPSC-CMs: 90.25±4.99%) was equivalent. While the field-potential durations were significantly longer in ViPSC-CMs than in AiPSC-CMs, measurements of action potential duration, beat period, spike amplitude, conduction velocity, and peak calcium-transient amplitude did not differ significantly between the two hiPSC-CM populations. Yet, our cardiac-origin iPSC-CM showed higher ADP and conduction velocity than previously reported iPSC-CM derived from non-cardiac tissues. Transcriptomic data comparing iPSC and iPSC-CMs showed similar gene expression profiles between AiPSC-CMs and ViPSC-CMs with significant differences when compared to iPSC-CM derived from other tissues. This analysis also pointed to several genes involved in electrophysiology processes to be responsible for the physiological differences observed between cardiac and non-cardiac-derived cardiomyocytes. ¬ Conclusions: AiPSC and ViPSC were differentiated into CMs with equal efficiency. Detected differences in electrophysiological properties, calcium handling activity, and transcription profiles between cardiac and non-cardiac derived cardiomyocytes demonstrated that 1) tissue of origin matters to generate a better-featured iPSC-CMs, 2) the sublocation within the cardiac tissue has marginal effects on the differentiation process.

Project description:Hypoplastic left heart syndrome (HLHS) is the most lethal congenital heart disease (CHD). The pathogenesis of HLHS is poorly understood and due to the likely oligogenic complexity of the disease, definitive HLHS-causing genes have not yet been identified. Postulating that impaired cardiomyocyte proliferation as a likely important contributing mechanism to HLHS pathogenesis, and we conducted a genome-wide siRNA screen to identify genes affecting proliferation of human iPSC-derived cardiomyocytes (hPSC-CMs). This yielded ribosomal protein (RP) genes as the most prominent class of effectors of CM proliferation. In parallel, whole genome sequencing and rare variant filtering of a cohort of 25 HLHS proband-parent trios with poor clinical outcome revealed enrichment of rare variants of RP genes. In addition, in another familial CHD case of HLHS proband we identified a rare, predicted-damaging promoter variant affecting RPS15A that was shared between the proband and a distant relative with CHD. Functional testing with an integrated multi-model system approach reinforced the idea that RP genes are major regulators of cardiac growth and proliferation, thus potentially contributing to hypoplastic phenotype observed in HLHS patients. Cardiac knockdown (KD) of RP genes with promoter or coding variants (RPS15A, RPS17, RPL26L1, RPL39, RPS15) reduced proliferation in generic hPSC-CMs and caused malformed hearts, heart-loss or even lethality in Drosophila. In zebrafish, diminished rps15a function caused reduced CM numbers, heart looping defects, or weakened contractility, while reduced rps17 or rpl39 function caused reduced ventricular size or systolic atrial dysfunction, respectively. Importantly, genetic interactions between RPS15A and core cardiac transcription factors TBX5 in CMs, Drosocross, pannier and tinman in flies, and tbx5 and nkx2-7 (nkx2-5 paralog) in fish, support a specific role for RP genes in heart development. Furthermore, RPS15A KD-induced heart/CM proliferation defects were significantly attenuated by p53 KD in both hPSC-CMs and zebrafish, and by Hippo activation (YAP/yorkie overexpression) in developing fly hearts. Based on these findings, we conclude that RP genes play critical roles in cardiogenesis and constitute an emerging novel class of gene candidates likely involved in HLHS and other CHDs.

Project description:The heart is a complex organ composed of multiple cell and tissue types. During early developmental stages, heart cells from different regions of the heart exhibit different patterns of gene expression, which are thought to significantly contribute to heart development and morphogenesis. Until recently, the lack of adequate tools prevented our ability to systematically profile gene expression in a cell type and anatomically-specific manner during heart development. Single cell RNA sequencing has emerged as a powerful approach that allows genome-wide analysis of gene expression in single cells. Using microfluidic-chip and droplet-based single-cell RNA sequencing platforms, we analyze cardiac cells during the early stages of heart development. We found, by principle component analysis, that the expression of cell cycle genes represents a major determinant of transcriptional variation in all analyzed cardiac cell types. Interestingly, when single cardiomyocytes (CMs) from different heart chambers were analyzed, we found that atrial ventricular canal derived CMs have reduced cell cycle activity compare with CMs from the left and right ventricular chambers. In addition, CMs in the trabecular myocardium exhibit reduced cell cycle activity than CMs in the compact myocardium. When CMs within the same chamber were segregated by their cell cycle phase, we found that CMs in the G2/M phase downregulate their sarcomeric and cytoskeletal markers. Finally, we revealed the expression of a signaling ligand from the endocardium that may repress trabecular CM proliferation, and an epicardial-derived ligand that can promote compact CM proliferation. Together these data highlight the variations in cell cycle activity to selectively promote cardiac chamber growth during development and the profound transcriptional shift within the same cell at different phases of cell cycle. Identifying alterations in the expression of key signaling molecules that drive CM proliferation may lead to greater understanding of the onset or progression of congenital heart disease.

Dataset Information

Genome-wide association mapping for cardiomyocyte ploidy identifies Shroom3 as responsible for hyperpolyploidy and ventricular dilation

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets