Project description:In order to understand the transcriptional regulatory program of cardiomyocytes perinatal transition, we mapped chromatin accessibility, transcription-centered long-range chromatin interactions as well as gene expression in cardiomyocyte undergoing perinatal transition.
Project description:β-Catenin signaling pathway regulates cardiomyocytes proliferation and differentiation, though its involvement in metabolic regulation of cardiomyocytes remains unknown. We used one-day-old mice with cardiac-specific knockout of β-catenin and neonatal rat ventricular myocytes treated with β-catenin inhibitor to investigate the role of β-catenin metabolism regulation in perinatal cardiomyocytes. Transcriptomics of perinatal β-catenin-ablated hearts revealed a dramatic shift in the expression of genes involved in metabolic processes. Further analysis indicated an inhibition of lipolysis and glycolysis in both in vitro and in vivo models. Finally, we showed that β-catenin deficiency leads to mitochondria dysfunction via the downregulation of Sirt1/PGC-1α pathway. We conclude that cardiac-specific β-catenin ablation disrupts the energy substrate shift that is essential for postnatal heart maturation, leading to perinatal lethality of homozygous β-catenin knockout mice.
Project description:Epigenetic changes in DNA and chromatin are implicated in organogenesis and cell differentiation. Through a genome-wide chromatin-immunoprecipitation DNA-sequencing approach (ChIP-seq) we analyses the enrichment of H3K79me2 and H3K4me3 (histone methylation marks associated with transcriptional activation) and H3K27me3 and H3K9me3 (histone methylation marks associated with transcriptional repression) in neonatal and adult cardiomyocytes. The histone methylation profile obtained was correlated with an Illumina gene expression profile from the same samples. Our results demonstrate that histone methylation, and in particular the DOT1L-mediated H3K79me2 mark, drives cardiomyogenesis through the definition of a specific transcriptional landscape Profiling of H3K79me2, H3K4me3, H3K27me3 and H3K9me3 in neonatal and adult cardiomyocytes
Project description:To date, there have been limited high quality libraries of cardiomyocyte maturation during the perinatal period, in part owing to the difficulty of isolating large perinatal cardiomyocytes. We previously developed a method utilizing large-particle fluorescent activated cell sorting (LP-FACS) to isolate adult cardiomyocytes for single cell RNA-seq (Kannan et al., Circ Res, 2019). We utilize this method to generate a reference of perinatal cardiomyocyte maturation.
Project description:Exclusion of Parkin from mitochondria of perinatal cardiomyocytes interrupts structural and molecular transformations essential to normal perinatal-adult mitochondrial replacement. mRNA-sequencing from cardiac total RNA was performed at P1, P21 and 5-week stages of nontransgenic (ntg) and human-Mfn2-overexpressing (Mfn2wt) hearts, and also of tet-off control (tetoff) and human-Mfn2 T111A/S442A-overexpressing (Mfn2AA) hearts.
Project description:Six2+ cap mesenchyme cells, also called nephron progenitor cells (NPC), are a multipotent stem cell population and precursors of all epithelial cell types of the nephron, the filtering unit of the kidney. In mammals, formation of new nephrons ceases perinatally associated with a surge in NPC differentiation. Current evidence indicates that perinatal “old” NPC have a greater tendency to exit the progenitor niche and differentiate into nascent nephrons than their embryonic “young” counterparts. Understanding the biological underpinnings of NPC aging may offer insights to rejuvenate old NPC and expand the progenitor pool. In the present study, we compared the chromatin landscape of young and old NPC and found common features reflecting their shared lineage but also intrinsic differences in chromatin accessibility and enhancer landscape supporting the view that old NPC and epigenetically poised for differentiation. Annotation of open chromatin regions and active enhancers uncovered the transcription factor Bach2 as a potential link between the pro-renewal MAPK/AP1 and pro-differentiation Six2/b-catenin pathways that might be of critical importance in regulation of NPC fate. Our data provide the first glimpse of the dynamic chromatin landscape of NPC and serve as a platform for future studies of the impact of genetic or environmental perturbations on the epigenome of NPC.
Project description:Epigenetic enzymes play critical roles in embryogenesis by defining higher-order chromatin structures required for the establishment of organ-specific transcriptional networks. In this study we investigated how the landscape of the histone 3 lysine 27 acetylation in absence of the histone methyltransferase Dot1L in cardiomyocytes during development. We conducted chromatin immunoprecipitation experiments for H3K27ac in embryonic (E16.5) and neonatal (P1) cardiomyocytes from Dot1L cardiomyocyte-specific conditional knock out and control mice. Overall, we identified alteration in the enrichment of acetylation of H3K27 in regulatory regions associated wih genes essential for cardiac patterning and cardiomyocyte maturation.
Project description:Exclusion of Parkin from mitochondria of perinatal cardiomyocytes interrupts structural and molecular transformations essential to normal perinatal-adult mitochondrial replacement. mRNA-sequencing from cardiac total RNA was performed at P1, P21 and 5-week stages of nontransgenic (ntg) and human-Mfn2-overexpressing (Mfn2wt) hearts, and also of tet-off control (tetoff) and human-Mfn2 T111A/S442A-overexpressing (Mfn2AA) hearts. Libraries from all P1 samples were prepared and analyzed together, and similarly all P21 libraries, and all 5-week libraries together. To facilitate comparison across time points by accounting for batch effect, new libraries were prepared starting from total RNA from selected P21 ntg and 5-week ntg hearts subjected to prior analysis, during the same batch preparation as all P1 samples, and analyzed together. Correction for differences observed between libraries prepared from the same total RNA, but at different times, allows comparison across timepoints.
Project description:Epigenetic changes in DNA and chromatin are implicated in organogenesis and cell differentiation. Through a genome-wide chromatin-immunoprecipitation DNA-sequencing approach (ChIP-seq) we analyses the enrichment of H3K79me2 and H3K4me3 (histone methylation marks associated with transcriptional activation) and H3K27me3 and H3K9me3 (histone methylation marks associated with transcriptional repression) in neonatal and adult cardiomyocytes. The histone methylation profile obtained was correlated with an Illumina gene expression profile from the same samples. Our results demonstrate that histone methylation, and in particular the DOT1L-mediated H3K79me2 mark, drives cardiomyogenesis through the definition of a specific transcriptional landscape