Project description:Cardiac fibrosis occurs in most cardiac diseases, which reduces cardiac muscle compliance, impairs both systolic and diastolic heart function and, ultimately, leads to heart failure. Using unbiased transcriptome profiling in a mouse model of myocardial infarction, we identified a cardiac-fibroblast enriched lncRNA (AK048087) named cardiac fibroblast-associated transcript (Cfast), which is significantly elevated after myocardial infarction. Here, we show that silencing Cfast expression by lentiviral shRNAs resulted in suppression of fibrosis-related gene expression and transdifferentiation of myofibroblasts into cardiac fibroblasts. We performed the RNA-seq profiling in both lentivirus Cfast knockdown and lentivirus scramble group in cardiac fibroblasts. Finally, the transcriptome analysis indicates that genes related to cell differentiation, cell migration, extracellular matrix organization downregulated in Cfast knockdown group.
Project description:Gβγ subunits are involved in many different signalling processes in various compartments of the cell, including the nucleus. To gain insight into the functions of nuclear Gβγ, we investigated the functional role of Gβγ signalling in regulation of GPCR-mediated gene expression in primary rat neonatal cardiac fibroblasts. Following activation of the angiotensin II type I receptor in these cells, Gβγ dimers interact with RNA polymerase II (RNAPII). Our findings suggest that Gβ1γ recruitment to RNAPII negatively regulates the fibrotic transcriptional response, which can be overcome by strong fibrotic stimuli. In these specific proteomics experiments, we compared the differential protein abundance in Gβ1 knockdown and WT cardiac fibroblasts following angiotensin II treatment using a bottom-up data-dependent approach.
Project description:Four transcription factors, GATA4, Hand2, MEF2C, Tbx5 (GHMT) activated cardiac gene expression in cardiac fibroblasts, suggesting that these factors are able to reprogram fibroblasts toward a cardaic cell fate. Total RNA isolated from adult cardiac fibroblasts transduced with empty retroviral vector or GHMT-retroviruses for 2, and 4 weeks.
Project description:Growth and expansion of ventricular chambers is essential during cardiogenesis and is achieved by proliferation of cardiac progenitors that are not fully differentiated. Disruption of this process can lead to prenatal lethality. In contrast, adult cardiomyocytes achieve growth through hypertrophy rather than hyperplasia. Although epicardial-derived signals may contribute to the proliferative process in myocytes, the factors and cell types responsible for development of the ventricular myocardial thickness are unclear. Moreover, the function of embryonic cardiac fibroblasts, derived from epicardium, and their secreted factors are largely unknown. Using a novel co-culture system, we found that embryonic cardiac fibroblasts induced proliferation of cardiomyocytes, in contrast to adult cardiac fibroblasts that promoted myocyte hypertrophy. We identified fibronectin, collagen and heparin-binding EGF-like growth factor as embryonic cardiac fibroblast-specific signals that collaboratively promoted cardiomyocyte proliferation in a paracrine fashion. b1 integrin was required for this proliferative response, and ventricular cardiomyocyte-specific deletion of b1 integrin in mice resulted in reduced myocardial proliferation and impaired ventricular compaction. These findings reveal a previously unrecognized paracrine function of embryonic cardiac fibroblasts in regulating cardiomyocyte proliferation. To identify candidate fibroblast-derived factors that promote myocyte proliferation, we isolated RNA from Nkx-YFP+ cardiomyocytes, embryonic cardiac fibroblasts, and adult cardiac fibroblasts and profiled mRNA expressions by microarray analyses. Arrays were performed using Affymetrix mouse Gene 1.0 ST arrays. Analysis was performed on three biological replicates of mouse embyonic cardiomyocytes, fibroblasts and adult cardiac fibroblasts.