Project description:Cardiomyocyte poly(A) RNA was sequenced from purified bulk cardiomyocytes collected from one male and female murine heart at postnatal day 2 (P2). Neonatal cardiomyocytes were isolated and purified (96% cardiomyocytes at P2) by Langendorff retrograde perfusion and immunomagnetic cell separation, respectively. We found evidence of sexual dimorphism with 9 differentially expressed genes (FDR<0.05) encoded on XY chromosomes in this RNA-Seq dataset.
Project description:Cardiac maturation lays the foundation for postnatal heart development and disease, yet little is known about the contributions of the microenvironment to cardiomyocyte maturation. By integrating single-cell RNA-sequencing data of mouse hearts at multiple postnatal stages, we construct cellular interactomes and regulatory signaling networks. Here we report switching of fibroblast subtypes from a neonatal to adult state and this drives cardiomyocyte maturation. Molecular and functional maturation of neonatal mouse cardiomyocytes and human embryonic stem cell-derived cardiomyocytes are considerably enhanced upon coculture with corresponding adult cardiac fibroblasts. Further, single-cell analysis of in vivo and in vitro cardiomyocyte maturation trajectories identify highly conserved signaling pathways, pharmacological targeting of which substantially delays cardiomyocyte maturation in postnatal hearts, and markedly enhances cardiomyocyte proliferation and improves cardiac function in infarcted hearts. Together, we identify cardiac fibroblasts as a key constituent in the microenvironment promoting cardiomyocyte maturation, providing insights into how the manipulation of cardiomyocyte maturity may impact on disease development and regeneration.
Project description:Since the proliferative capacity of cardiomyocytes is extremely limited in the adult mammalian hearts, the irreversible loss of cardiomyocytes following cardiac injury markedly reduces cardiac function, leading to cardiac remodeling and heart failure. However, the early neonatal mice have a strong ability in cardiomyocyte proliferation and cardiac regeneration after heart damage such as apical resection. Besides of cardiomyocytes, non-myocytes in heart tissue also play important roles in the regeneration process. Previous studies showed that cardiac macrophages, regulatory T cells and CD4+ T cells are all involved in regulating the myocardial regeneration process. However, the roles of other cardiac immune cells in cardiac regeneration remains to be elucidated. B cells is a prominent immune cell in injured heart; here we discovered the indispensable function of cardiac B cells in improving cardiomyocyte proliferation and heart regeneration in neonatal mice.
Project description:Infected neonatal mouse cardiomyocyte; COMMENT: Submitter has not provided GEO with full dataset as described in Nat Genet. 2004 Feb;36(2):123-30.
Project description:We used a transcriptomic approach to systematically compare the response to inflammatory stimuli for two murine cardiomyocyte models. Our results indicate that murine neonatal cardiomyocytes (NNC) are able to exhibit a pronounced response upon inflammatory stimuli, while HL-1 cells were predominantly recruiting transcripts corresponding to Jak-Stat-signalling. RNA from murine HL-1 cardiomyocytes and isolated neonatal cardiomyocytes (NNC) stimulated by infectious (PCI) serum or LPS or a cytokine mix (CM) were extracted (n=4 each group) and subjected to microarray analysis for comparison of transcriptomic responses.
Project description:The adult mammalian heart is incapable of regeneration following injury. In contrast, the neonatal mouse heart has a transient ability to regenerate, however the molecular mechanism that mediates this regenerative response is not fully understood. Here, by single-nucleus RNA sequencing we map the transcriptome landscape of cardiomyocytes in neonatal mouse hearts at healthy, regenerative, and remodeling conditions. We show that an immature cardiomyocyte population enters cell-cycle in response to injury. Absence of this cardiomyocyte population overtime is associated with the loss of the ability of the heart to regenerate. We show a defined injury response in these cardiomyocytes, including activation of transcription factors NFYa and NFE2L1, which play proliferative and protective roles, respectively. We further show that overexpression of these two factors in vivo promotes heart regeneration. Thus, these findings refined our understanding of cellular basis of neonatal heart regeneration and reveal dynamic transcriptome landscape of cardiomyocytes in response to injury.
Project description:Background: The adult mammalian heart has limited capacity for regeneration following injury, whereas the neonatal heart can readily regenerate within a short period after birth. To uncover the molecular mechanisms underlying neonatal heart regeneration, we compared the transcriptomes and epigenomes of regenerative and non-regenerative mouse hearts over a 7-day time period following myocardial infarction. Methods: RNA-Seq, H3K27ac ChIP-Seq and H3K27me3 ChIP-Seq were performed on ventricular samples from regenerative P1 or non-regenerative P8 mouse hearts at +1.5d, +3d and +7d after MI or Sham surgery to assemble the transcriptome, active chromatin and repressed chromatin landscapes during neonatal heart regeneration. Dynamic enhancer landscapes from mouse hearts during cardiac development were analyzed using data from ENCODE. Effects on cardiomyocyte proliferation and cardiac function from selected factors identified in this study were tested using BrdU/EdU pulse-labeling or mouse models coupled with immunohistochemistry and echocardiography. Results: By integrating gene expression profiles with histone marks associated with active or repressed chromatin, we identified transcriptional programs underlying neonatal heart regeneration and the blockade to regeneration in later life. Our results reveal a unique immune response in regenerative hearts and an embryonic cardiogenic gene program that remains active during neonatal heart regeneration. Among the unique immune factors and embryonic genes associated with cardiac regeneration, we identified Ccl24, which encodes a cytokine, and Igf2bp3, which encodes an RNA-binding protein, as previously unrecognized regulators of cardiomyocyte proliferation. Conclusions: Our data provide insights into the molecular basis of neonatal heart regeneration and identify genes that might be modulated to promote heart regeneration.
Project description:To investigate the role of the glucocorticoid receptor (GR) in the regulation of cardiomyocyte maturation and proliferation, we established a cardiomyocyte-specific GR knock-out (GR-cKO) mouse model by Cre-Lox technology. We thus performed gene expression profiling analysis using data obtained from RNA-seq of cardiomyocytes isolated from GR-cKO and control mouse models at neonatal stage and cultured in vitro. Our analyses unveiled a role for GR in regulating gene networks related to the energetic metabolism, which in turn may impact on cardiomyocyte proliferative and regenerative ability.