Project description:Significance Heart disease accounts for 1 in 4 deaths in the United States annually, making it one of the leading causes of death and related morbidity resents a significant economic burden. Mammalian cardiomyocytes are terminally differentiated with low turnover rate, insufficient to repopulate myocardium after heart attack caused by myocardial infarction (MI). As such, there is an urgent need for the development of non-invasive, effective, and efficient therapeutic approaches for treating MI. One strategy is to promote proliferation in mature cardiomyocytes, inspired by the observation of a transient regenerative window in neonatal mouse cardiomyocytes. During postnatal development, it is believed that cardiomyocytes exit cell cycle in response to high oxygen environment and a metabolic shift to oxidative phosphorylation. Strategies to lower oxidative stress in neonatal mouse hearts to prolong regenerative time window have been reported. While many studies have focused on mitigating injury-related ROS, it is not clear whether the developmental ROS increase in neonatal cardiomyocytes plays a role during postnatal myocardial maturation and establishment of injury response. The following study details the crucial role of neonatal ROS as signaling molecules in cardiomyocyte injury response after MI.
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: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: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:Mutations or decreased expression of RNA-binding proteins (mRBPs) can lead to cardiomyopathies in humans. Here we defined RBPs in healthy and diseased primary cardiomyocytes at a system-wide level by RNA Interactome Capture. This identified 67 novel cardiomyocyte specific RBPs including several contractile proteins. Furthermore, we evaluated dynamic binding capacities of RBPs during pathologyical cardiac hypertrophy and identified Cytoplasmic polyadenylation element binding protein 4 (Cpeb4) as a dynamic RBP, regulating cardiac growth both in vitro and in vivo.
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.
Project description:Evaluate the change in transcription factors that have a role in human mesenchymal stem cell (hMSC) commitment to a cardiomyocyte lineage when co-cultured for 4 days with rat neonatal cardiomyocytes and before acquiring a recognizable cardiac phenotype. A myocardial microenvironment was generated by dissociating neonatal rat hearts and establishing cardiomyocyte primary cultures. HumanMSCs constitutively labeled with dsRed localized to the cell's mitochondria were either grown separately (control) or added to the cardiomyocyte primary cultures and grown for 4 days. dsRed fluorescent hMSCs were harvested from co-cultures at 4 days using a FACscan flow cytometer. The RNA for the microarray analysis was prepared from three biologically separate samples of hMSCs co-cultured for 4 days and from hMSCs grown separately for 4 days (control).
Project description:Mammalian cardiomyocytes rapidly mature after birth, with hallmarks such as cell-cycle exit, binucleation, and metabolic switch to oxidative phosphorylation of lipids. The causes and transcriptional programs regulating cardiomyocyte maturation are not fully understood yet. Thus, we performed single cell RNA-seq of neonatal and postnatal day 7 rat hearts to identify the key factors for this process and found AP-1 as a key factor to regulate cardiomyocyte maturation. To find the mechanism of AP-1 during cardiomyocyte maturation, we performed RNA-seq analysis of neonatal rat ventricular cardiomyocytes and found Ap-1 promote cardiomyocyte maturation by regulating cardiomyocyte metabolism.