Project description:Heart failure (HF) is a global concern, marked by limited therapeutic options. While existing studies primarily focus on cardiomyocytes, there is a notable absence of drugs targeting noncardiomyocytes for HF. We focused on cardiac fibroblasts (CFs), utilising single-cell RNA-sequencing analysis. The analysis of murine hearts revealed one subcluster exclusive to the HF stage. The transcription factor c-Myc is specifically expressed in heart failure-specific fibroblasts (HF-Fibro). Cardiac fibroblast-specific deletion of c-Myc ameliorates pressure overload-induced cardiac dysfunction without affecting fibrosis. To elucidate the molecular function of c-Myc in HF-Fibro, transcriptome analysis by RNA-seq was conducted, in vivo.
Project description:Heart failure (HF) is a major global problem with increasing numbers of patients and deaths in many countries. Existing studies on HF have focused primarily on cardiomyocytes, with few studies targeting non-cardiomyocytes. This study focused on cardiac fibroblasts (CFs) as a cause of HF. Single-cell RNA sequencing of mouse hearts revealed six distinct subclusters of CFs at various stages after pressure overload, with one subcluster being specific to the HF stage. The transcription factor c-Myc is specifically expressed in HF-specific CFs. CFs-specific deletion of c-Myc ameliorates pressure overload-induced cardiac dysfunction without affecting fibrosis. The chemokine Cxcl1 is highly expressed in HF-specific CFs and downregulated in CFs-specific c-Myc knockout mice. Chromatin immunoprecipitation analysis revealed that c-Myc binds to the promoter region of Cxcl1 in CFs. Cxcr2, the receptor for Cxcl1, is expressed in cardiomyocytes, and blockade of the Cxcl1-Cxcr2 signalling pathway prevents pressure overload-induced cardiac dysfunction. The addition of CXCL1 reduces the contractility of cardiomyocytes of neonatal rats and human iPS-derived cardiomyocyte organoids. Human CFs from failing hearts expressed c-MYC and CXCL1, while CFs from control hearts did not. These findings suggest that HF-specific CFs play an important role in inducing HF by upregulating c-Myc and Cxcl1 and that CFs could be a novel therapeutic target for HF.
Project description:Aim - Pathological cardiac remodeling is characterized by cardiomyocyte hypertrophy and fibroblast activation, which can ultimately lead to heart failure (HF). Genome-wide expression analysis on heart tissue has been instrumental for the identification of molecular mechanisms at play. However, these data were based on signals derived from all cardiac cell types. Here we aimed for a more detailed view on molecular changes driving cardiomyocyte hypertrophy and failure to aid in the development of therapies to reverse maladaptive remodeling. Methods and results - Utilizing cardiomyocyte-specific reporter mice exposed to pressure overload by transverse aortic banding (TAB), we obtained gene expression profiles of hypertrophic (one-week TAB) and failing (eight-weeks TAB) cardiomyocytes. We identified subsets of genes differentially regulated and specific for either stage. Among these, we found upregulation of known marker genes for HF, such as Nppb and Myh7. Additionally, we identified a set of genes specifically upregulated in failing cardiomyocytes and that so far have not been studied in HF, including the platelet isoform of phosphofructokinase (PFKP). Human cardiomyocytes subjected to 7-day NE/AngII treatment recapitulated the upregulation of the failure-induced genes indicating conservation. RNA-seq on failing and healthy human hearts confirmed increased expression for several failure-induced genes and allowed for expressional correlation to NPPB/MYH7. Finally, suppression of Pfkp in PE-treated primary cardiomyocytes reduced stress-induced gene expression and hypertrophy, suggesting a role in cardiomyocyte failure. Conclusion - Using cardiomyocyte-specific transcriptomic analysis we identified novel failure-induced genes relevant for human HF, and show that PFKP is a conserved failure-induced gene that can modulate cardiomyocyte stress response.
Project description:The microtubule (MT) cytoskeleton can provide a mechanical resistance that can impede the motion of contracting cardiomyocytes. Yet a role of the MT network in human heart failure is unexplored. Here we utilize mass spectrometry to characterize changes to the cytoskeleton in human heart failure. Proteomic analysis of left ventricle tissue reveals a consistent upregulation and stabilization of intermediate filaments and MTs in human heart failure. This dataset includes left ventricular (LV) myocardium from 34 human hearts – either non-failing (NF) or failing hearts. NF hearts are subdivided into normal or compensated hypertrophy (cHyp), while failing hearts are subdivided into ischemic cardiomyopathy (ICM), dilated cardiomyopathy (DCM), and hypertrophic cardiomyopathy with preserved or reduced ejection fraction (HCMpEF and HCMrEF, respectively). Further details on patient classification and in vivo parameters on each heart are listed in sample details.txt.
Project description:Mitochondrial proteomics was used to identify energy metabolic derangements that occur during the early stages of heart failure in well-defined mouse models. Levels of β-hydroxybutyrate dehydrogenase 1 (BDH1), a key enzyme in ketone oxidation, was upregulated. 13C-substrate flux studies and metabolomic profiling confirmed that the hypertrophied and early stage failing heart shifts to ketone bodies as a fuel source in the context of reduced oxidation of fatty acids, the chief substrate for the normal heart. This fuel shift is associated with an expansion of the acetyl pool and reduced levels of NAD+ levels resulting in increased mitochondrial protein acetylation. Myocardium of humans with heart failure also exhibited mitochondrial protein hyperacetylation. We propose that a shift to ketones as a fuel source leads to maladaptive bioenergetic consequences during the development of heart failure.
Project description:Epigenetic status has been linked to cardiac hypertrophy and heart failure. Histone deacetylase inhibitors are promising drugs for preventing cardiac remodeling. We previously demonstrated very different patterns of histone H3 lysine 9 trimethylation (H3K9me3) and histone H3 lysine 4 trimethylation (H3K4me3) in failing hearts compared to control hearts in both animal models and clinical heart specimens. Here, we focused on a heart failure-specific histone modification, H3K9me3, and investigated the prognostic efficacy of administering a histone H3K9 methyltransferase inhibitor, chaetocin, to Dahl salt-sensitive rats, an animal model of heart failure. Chaetocin delayed the timing of transition from cardiac hypertrophy to heart failure, and prolonged survival in this animal model. Mitochondrial dysfunction was improved with inhibitor use in the failing heart. ChIP-seq analysis demonstrated that heart failure caused an increase in H3K9me3 alignments in thousands of repetitive elements, including regions neighboring mitochondrial genes, and a corresponding reduction of this effect with inhibitor use. However, at 35 loci, heart failure was conversely associated with a reduction in H3K9me3 alignments, and inhibitor use reversed this effect. These data suggest that excessive heterochromatinization of repetitive elements in the failing heart might impair pumping function with mitochondrial gene silencing. H3K9 methyltransferase inhibitors may be a promising novel therapy for chronic heart failure.
Project description:To identify a novel target for the treatment of heart failure, we examined gene expression in the failing heart. Among the genes analyzed, 12/15 lipoxygenase (12/15-LOX) was markedly up-regulated in heart failure. To determine whether increased expression of 12/15-LOX causes heart failure, we established transgenic mice that overexpressed 12/15-LOX in cardiomyocytes. Echocardiography showed that 12/15-LOX transgenic mice developed systolic dysfunction. Cardiac fibrosis increased in 12/15-LOX transgenic mice with advancing age, and was associated with the infiltration of macrophages. Consistent with these observations, cardiac expression of monocyte chemoattractant protein-1 (Mcp-1) was up-regulated in 12/15-LOX transgenic mice compared with wild-type mice. Treatment with 12-hydroxy-eicosatetraenotic acid, a major metabolite of 12/15-LOX, increased MCP-1 expression in cardiac fibroblasts and endothelial cells, but not in cardiomyocytes. Inhibition of Mcp-1 reduced the infiltration of macrophages into the myocardium and prevented both systolic dysfunction and cardiac fibrosis in 12/15-LOX transgenic mice. Likewise, disruption of 12/15-LOX significantly reduced cardiac Mcp-1 expression and macrophage infiltration, thereby improving systolic dysfunction induced by chronic pressure overload. Our results suggest that cardiac 12/15-LOX is involved in the development of heart failure and that inhibition of 12/15-LOX could be a novel treatment for this condition. Heart failure is still one of the leading causes of death worldwide. Therefore, it is important to elucidate the underlying mechanisms of heart failure and develop more effective treatments for this condition. To clarify the molecular mechanisms of heart failure, we performed microarray analysis using cardiac tissue samples obtained from a hypertensive heart failure model (Dahl salt-sensitive rats). ~300 genes showed significant changes of expression in the failing hearts compared with control hearts. Among the genes analyzed, 12/15-lipoxygenase (12/15-LOX) was most markedly up-regulated in failing hearts compared with control hearts .
Project description:We have utilized the RNA-Seq technology to identify genes with distinct expression patterns between failing and non-failing hearts. In an era of next-generation sequencing studies, our study demonstrates how knowledge gained from a small set of samples with accurately measured gene expressions using RNA-Seq can be leveraged as a complementary strategy to discern the genetics of complex disorders. Identify the signature genes based on RNA-seq come from six Heart Failure and healthy individuals. Validation is based on Affymetrix microarray of a total of 313 individuals with/without Heart Failure.