Dataset Information

Myocardial-intrinsic defects underlie an Rbfox-mediated zebrafish model of hypoplastic left heart syndrome

ABSTRACT: Hypoplastic left heart syndrome (HLHS) is characterized by underdevelopment of left sided structures including the ventricle, valves, and aorta1. Although the mechanisms of disease pathogenesis remain elusive due to a paucity of candidate genes and animal models, prevailing paradigm suggests that HLHS is a multigenic disease of co-occurring phenotypes2,3. Here, we report that zebrafish lacking two orthologs of the RNA binding protein RBFOX2, a gene previously linked to HLHS in humans4,5, display cardiovascular defects overlapping those in HLHS patients. In contrast to current models, we demonstrate that co-existing ventricular, valve, and aortic deficiencies in rbfox mutant zebrafish arise secondary to impaired myocardial function as all three phenotypes are rescued when Rbfox is expressed specifically in the myocardium. On a molecular and cellular level, we find diminished expression and alternative splicing of sarcomere and mitochondrial components in rbfox-deficient hearts that compromise sarcomere assembly and mitochondrial respiration, respectively. Injection of human RBFOX2 mRNA restores ventricular structure and function in rbfox mutant zebrafish, while HLHS-linked RBFOX2 variants fail to rescue. Taken together, our data suggest that mutations in RBFOX2 are causal for HLHS pathogenesis and provide a complimentary paradigm for HLHS emergence where co-existing ventricular, valve, and aortic deficiencies have a monogenic etiology caused by myocardial dysfunction.

INSTRUMENT(S): Liquid Chromatography MS - negative - hilic

SUBMITTER: Shakchhi Joshi

PROVIDER: MTBLS4176 | MetaboLights | 2022-07-12

REPOSITORIES: MetaboLights

ACCESS DATA

Similar Datasets

Project description:Background Sunitinib is a small molecule tyrosine kinase inhibitor approved for the treatment of diverse cancers. Despite widespread clinical approval the associated cardiovascular toxicity sequelae are of concern; high grade toxicities may lead to dose reduction, interruption or discontinuation. Thus, an effective strategy for the early detection of cardiac damage in the context of sunitinib treatment is warranted. Although yet to be fully elucidated, molecular pathways and kinases implicate include those related to cardiac energy metabolism. We hypothesised that plasticity in cardiac metabolism could represent a novel early marker of cardiotoxicity. Methods and Results Female Balb/CJ mice (n = 36) or Sprague-Dawley rat (n = 12) models were treated with sunitinib. Physiological parameters were measured. An hypothesis driven cardiac positron emission tomography (PET) approach was implemented to investigate alterations in myocardial glucose, fatty acid and oxidative metabolism. Following treatment, blood pressure increased, whilst left ventricular ejection fraction decreased in both models. Increased myocardial glucose uptake after 48 hours indicated early perturbations in glucose metabolism. Myocardial fatty acid metabolism appeared increased as a result of sunitinib treatment indicated by PET but electron microscopy revealed significantly increased storage of lipids in the myocardium. Proteomic analyses indicated that oxidative metabolism, fatty acid β-oxidation and mitochondrial dysfunction were among the top cardiac signalling pathways perturbed by sunitinib treatment. [11C]Acetate-PET data suggested a decrease in myocardial perfusion following 5 days of treatment. Conclusions Data implicates sunitinib as a mediator of compromised myocardial energy metabolism. Increased reliance on glycolysis, increases in myocardial lipid deposition and perturbed mitochondrial function may ultimately result in a fundamental energy crisis manifesting as compromised cardiac function, the long term effects of which are unknown. Our data support the utility of an hypothesis driven PET approach to monitor cardiac metabolic pathway remodelling in response to sunitinib, which may ultimately have clinical utility as a novel safety imaging biomarker strategy.

Project description:The cellular and molecular aspects of post-infarct left-ventricle remodeling in presence of type-2 diabetes is poorly understood. In this study we have addressed the cellular and molecular aspects underlying post-infarct left-ventricle remodeling in type 2 diabetic (T2DM) mice using genome-wide mRNA-sequencing. Myocardial infarction was induced by ligating left-anterior descending artery (LAD) in 12-14 month old T2DM and control mice. Cardiac MRI was performed at baseline, day 7 and 14 post-LAD ligation. Blood and tissue samples were collected for biochemical and immunohistochemical, molecular biology analysis after sacrification at day 7 and 14. Genome-wide mRNA sequencing analysis was performed from left-ventricular tissues collected at day 7 post-LAD ligation. Mitochondrial dynamics, Leukocyte recruitment and Collagen I deposition were analyzed using electron microscopy, fluorescent assisted cell sorting (FACS) and fourier-transform infra-red (FTIR) spectroscopy from left ventricular tissues collected at day 7 and 14 post-LAD ligation. Cardiac ejection fraction (EF) and stroke volume (SV) were significantly reduced along with increased mortality in T2DM compared to controls. Ingenuity pathway analyses of differentially expressed genes were enriched for mitochondrial dysfunction, TCA cycle and fatty acid oxidation. Additionally, upstream transcription factor analysis showed inhibition of PGC1a, PGC1b, ESRRA, ESRRB and TFAM in infarcted myocardium of T2DM mice. Electron microscopy analysis showed an altered mitochondrial dynamics and cardiomyocyte death in ischemic myocardium of T2DM mice. Leukocytes exhibited an altered phenotype in ischemic myocardium of T2DM mice. Neovascularization was impaired and collagen deposition was increased in ischemic myocardium of T2DM mice. We conclude that an altered mitochondrial dynamics, cell death modalities, leukocyte phenotype, neovascularization responses and fibrosis may contribute to an increased mortality after myocardial infarction in T2DM. Modulation of mitochondrial dynamics and cardiomyocyte cell death modalities may offer a novel therapeutic target.

Dataset Information

Myocardial-intrinsic defects underlie an Rbfox-mediated zebrafish model of hypoplastic left heart syndrome

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure