GSE121234
Distinct TCF7L2 genomic occupancies discern chromatin states in the neonatal and diseased mammalian myocardium [RNA-Seq]
In mammals, Wnt pathway is activated during both heart regeneration post-injury and disease. Our previous work described the role of nuclear Wnt effectors B-catenin and Transcription factor 7-like 2 (TCF7L2) in heart disease progression; revealing GATA4 as a Wnt-repressor in the healthy adult heart. However, there is an urgent need to dissect molecular players distinguishing regenerative vs. disease-specific responses. In this study, we report a GATA4-B-catenin interaction in the regenerative neonatal myocardium, despite high TCF7L2 expression. TCF7L2 displayed strikingly unique genomic occupancies: proximal in neonatal and distal in diseased hearts. Integrative genomic and transcriptomic analyses showed that TCF7L2 differentially occupied and regulated fatty acid metabolic genes in the neonatal; and cardiac developmental and vasculogenesis genes in the diseased hearts, clearly discerning these two cardiac states. De-novo motif search identified TEAD as a commonly enriched motif in both TCF7L2 and GATA4-bound regions in the neonatal hearts, suggesting its potential role in providing a regenerative context to this GATA4-B-catenin interaction. Altogether, our study mapped for the first time, novel genome-wide TCF7L2 and GATA4 targets in the neonatal hearts and identified stage-specific roles for the cardiac Wnt-GATA4 complex. These findings demonstrate strong context-specificity of the cardiac Wnt-nuclear complex, which can be further exploited for therapeutic avenues. Purpose: The aim of this study was to investigate the transcriptome profiles (RNA-seq) of WT postnatal day 6 murine cardiac ventricles; and compare them to our previously published (GSE97762) adult and diseased myocardium transcriptomes. Methods: P6 cardiac ventricular tissue mRNA profiles were obtained using deep sequencing, in triplicates, using Illumina HiSeq4000. The sequence reads that passed quality filters were analyzed at the transcript isoform level with TopHat followed by DESeq2. qPCR validation was performed using TaqMan and SYBR Green assays Conclusions: Our study identified distinct transcriptomic signatures of P6 murine cardiac ventricles, in comparison to healthy or diseased adult heart. Particularly, despite high Wnt signaling activities and cardiomyocytes cell cycling in both P6 and diseased hearts, P6 hearts are regenerative in nature, while the diseased hearts are not. Overall design: Gene expression profiling from murine P6 cardiac ventricles.