P53-dependent mitochondrial compensation in heart failure with preserved ejection fraction
Ontology highlight
ABSTRACT: BACKGROUND: Heart failure with preserved ejection fraction (HFpEF) accounts for 50% of heart failure patients. Clinically, HFpEF prevalence show age and gender biases. Although the majority of HFpEF patients are elderly, there is an emergence of young HFpEF patients. A better understanding of the underlying pathogenic mechanism is urgently needed. Here, we aimed to determine the role of aging in the pathogenesis of HFpEF. METHODS AND RESULTS: HFpEF dietary regimen (HFD + L-NAME) was used to induce HFpEF in wildtype and telomerase RNA knockout mice (mTRG2 and mTRG3), an aging murine model. First, both male and female animals develop HFpEF equally. Second, cardiac wall thickening preceded diastolic dysfunction in all HFpEF animals. Third, accelerated HFpEF onset was observed in mTRG2 (at 6-weeks) and mTRG3 (at 4-weeks) compared to wildtype (8-weeks). Fourth, we demonstrate that mitochondrial respiration transitioned from compensatory state (normal basal yet loss of maximal respiratory capacity) to dysfunction (loss of both basal and maximal respiratory capacity) in a p53 dosage dependent manner. Last, using myocardial-specific p53 knockout animals, we demonstrate that p53 is necessary for the development of HFpEF. CONCLUSIONS: Here we demonstrate that p53 activation is critical for the pathogenesis of HFpEF. We show that short telomere animals exhibit a basal level of p53 activation, mitochondria upregulate mtDNA encoded genes as a mean to compensate for blocked mitochondrial biogenesis, and loss of myocardial p53 prevents HFpEF upon HFD + L-NAME challenge.
Project description:Left ventricular (LV) diastolic dysfunction is a hallmark of Heart Failure with preserved Ejection Fraction (HFpEF), an escalating global health challenge. We demonstrated selective depletion of the oxidized form of nicotinamide adenine dinucleotide (NAD+) and the rate-limiting enzyme of the NAD+ biosynthetic salvage pathway, nicotinamide phosphoribosyltransferase (NAMPT), in human myocardium with LV diastolic dysfunction. We showed that NAD+ can be replenished in human myocardium with diastolic impairment ex vivo, despite reduced NAMPT expression. In a murine model of HFpEF [a combination exposure to high-fat diet (HFD) and L-NG-Nitro arginine methyl ester (L-NAME)], we compared the benefits of NAD+ precursor supplementation versus dietary intervention. We tested NAD+ repletion by nicotinamide riboside (NR) supplementation using two clinically-relevant strategies: 1) Prophylactic NR repletion before HFpEF onset, and 2) Therapeutic NR repletion after the development of HFpEF. We found that dietary intervention (replacement of HFD and L-NAME with healthy diet) restored myocardial insulin-dependent glucose uptake and glycolysis but did not rescue HFpEF. In contrast, both NAD+ repletion strategies prevented or rescued HFpEF, respectively, plausibly due to restoration of myocardial iron homeostasis, recoupling of glycolysis to the TCA cycle, and upregulation of antioxidant defense.
Project description:Clinical management of heart failure with preserved ejection fraction (HFpEF) is hindered by a lack of disease-modifying therapies capable of altering its distinct pathophysiology. Despite the widespread implementation of a “two-hit” model of cardiometabolic HFpEF to inform precision therapy, which utilizes ad libitum high-fat and 0.5% N(ω)-nitro-L-arginine methyl ester (HFD+L-NAME) diet, we observe that C57BL6/J mice exhibit less cardiac diastolic dysfunction in response to HFD+L-NAME. Genetic strain-specific single-nucleus transcriptomic analysis identified disease-relevant genes that enrich oxidative metabolic pathways within cardiomyocytes. Because C57BL/6J mice are known to harbor a loss-of-function mutation affecting the inner mitochondrial membrane protein nicotinamide nucleotide transhydrogenase (Nnt), we used an isogenic model of Nnt loss-of-function to determine whether intact NNT is necessary for the pathological cardiac manifestations of HFD+L-NAME. Twelve-week-old mice cross-bred to isolate wild-type (Nnt+/+) or loss-of-function (Nnt-/-) Nnt in the C57BL/6N background, were challenged with HFD+L-NAME for 9 weeks (n = 6-10). Nnt+/+ mice exhibited impaired ventricular diastolic relaxation and pathological remodeling, as assessed via E/e’ (42.8 vs. 21.5, P = 1.2e-10), E/A (2.3 vs 1.4, P = 4.1e-2), diastolic stiffness (0.09 vs 0.04 mmHg/μL, P = 5.1e-3), and myocardial fibrosis (P = 2.3e-2). Liquid chromatography and mass spectroscopy exposed a 40.0% reduction in NAD+ (P = 8.4e-3) and a 38.8% reduction in GSH:GSSG (P = 2.6e-2) among Nnt+/+ mice after HFD+L-NAME feeding. Using single-nucleus ligand-receptor analysis, we implicate fibroblast growth factor 1 (Fgf1) as a putative NNT-dependent mediator of cardiomyocyte-to-fibroblast signaling of myocardial fibrosis. Together, these findings underscore the pivotal role of mitochondrial dysfunction in HFpEF pathogenesis and position both NNT and Fgf1 as novel therapeutic targets.
Project description:In this project we explore the cellular heterogeneity of a mouse model of heart failure with preserved ejection fraction (HFpEF) involving a two-hit model of feeding a high fat diet (HFD) along with L-NAME administration. Healthy adult male mice (C57BL/6J inbred) were fed either a normal chow diet or HFD/L-NAME for 10 weeks or 15 weeks before performing sequencing experiments. Both cardiomyocytes (CMs) and total interstitial population (TIP) were captured using a protocol to jointly capture and sequence single-nuclei (for cardiomyocytes) and single-cells (for TIP) using the 10x Genomics Chromium system.
Project description:Aims: Heart failure with preserved ejection fraction (HFpEF) is a multifactorial disease that constitutes several distinct phenotypes, including a common cardiometabolic phenotype with obesity and type 2 diabetes mellitus. Treatment options for HFpEF are limited, and development of novel therapeutics is hindered by the paucity of suitable preclinical HFpEF models that recapitulate the complexity of human HFpEF. Metabolic drugs, like Glucagon Like Peptide Receptor Agonist (GLP-1RA) and Sodium Glucose Transporter 2 inhibitors (SGLT2i), have emerged as promising drugs to restore metabolic perturbations and may have value in the treatment of the cardiometabolic HFpEF phenotype. We aimed to develop a multifactorial HFpEF mouse model that closely resembles the cardiometabolic HFpEF phenotype, and evaluated the GLP-1 RA liraglutide and a SGLT2i dapagliflozin. Methods&Results: Aged (18-22 months old) female C57BL/6J mice were fed a standardized chow (CTRL) or high fat diet (HFD) for 12 weeks. After 8 weeks HFD, Angiotensin-II (ANGII), was administered for 4 weeks via osmotic mini-pumps. HFD+ANGII resulted in a cardiometabolic HFpEF phenotype, including obesity, impaired glucose handling and metabolic dysregulation with inflammation. The multiple-hit resulted in typical clinical HFpEF features, including cardiac hypertrophy and fibrosis with preserved fractional shortening but with impaired myocardial deformation, atrial enlargement lung congestion, and elevated blood pressures. Treatment with liraglutide attenuated the cardiometabolic dysregulation and improved cardiac function, with reduced cardiac hypertrophy, less myocardial fibrosis, and attenuation of atrial weight, natriuretic peptide levels, and lung congestion. Dapagliflozin treatment improved glucose handling, but had mild effects on the HFpEF phenotype. Conclusions: We developed a mouse model that recapitulates the human HFpEF disease, providing a novel opportunity to study disease pathogenesis and development of enhanced therapeutic approaches. We furthermore show that attenuation of cardiometabolic dysregulation may represent a novel therapeutic target for treatment of HFpEF.
Project description:Heart failure with preserved ejection fraction (HFpEF) is increasingly common but its pathogenesis is poorly understood. The ability to assess genetic and pharmacologic interventions is hampered by the lack of robust pre-clinical mouse models of human HFpEF. We have developed a novel “2-hit” mouse model, which combines obesity and insulin resistance with chronic pressure overload to recapitulate clinical features of HFpEF. C57Bl6/NJ mice fed a high fat diet for at least 10 weeks were administered an AAV8-driven vector resulting in constitutive overexpression of mouse Renin1d. Control mice, HFD only, Renin only and HFD-Renin (aka “HFpEF”) littermates underwent a battery of cardiac and extracardiac phenotyping. HFD-Renin mice demonstrated obesity and insulin resistance, a 2-3-fold increase in circulating renin levels and resulted in 30-40% increase in LVH hypertrophy, preserved systolic function, and diastolic dysfunction indicated by altered E/e’, IVRT, and strain measurements; increased left atrial mass; elevated natriuretic peptides; and exercise intolerance. The transcriptomic and metabolomic signature of HFpEF indicates upregulation of fibrotic pathways and downregulation of metabolic pathways, in particular branched chain amino acid catabolism, similar to human HFpEF data. Treatment of these mice with the sodium-glucose cotransporter 2 inhibitor empagliflozin, a powerful but incompletely understood HFpEF therapy, showed improvement in exercise tolerance, left heart enlargement, and insulin homeostasis. The HFD-Renin mouse model recapitulates many critical features of human HFpEF and allows for dissection of how individual pathogenic drivers contribute to cardiac and peripheral metabolic changes. Multiple HFpEF models will also allow for orthogonal studies and increase validity in pre-clinical research efforts.
Project description:Heart failure is a disease with increasing prevalence, while present treatment options, especially for heart failure with preserved ejection fraction (HFpEF), are inadequate. Hypertension and obesity-related metabolic dysfunctions are important risk factors for HFpEF development and progression. Nitro-oleic acid (NO2-OA) impacts metabolic processes by improving glucose tolerance and adipocyte function. We sought to unravel effects of NO2-OA on cardiac function. Mice were fed for 15 weeks with high fat diet combined with endothelial nitric oxide synthase inhibitor (L-NAME). During the last 4 weeks treatment with nitro-oleic acid or vehicle was administered via osmotic pumps. Finally mice were sacrificed, left ventricular tissue harvested, snapfrozen in liquid nitrogen and stored at -80°C until protein isolation.
Project description:Heart failure affects 2–3% of adult Western population. Prevalence of heart failure with preserved left ventricular (LV) ejection fraction (HFpEF) increases. Studies suggest HFpEF patients to have altered myocardial structure and functional changes such as incomplete relaxation and increased cardiac stiffness. We hypothesised that patients undergoing elective coronary bypass surgery (CABG) with HFpEF characteristics will show distinctive gene expression compared to patients with normal LV physiology. Myocardial biopsies for mRNA expression analysis were obtained from sixteen patients with LV ejection fraction ≥ 45%. Five out of 16 patients (31%) had echocardiographic characteristics and increased NTproBNP levels indicative of HFpEF and this group was used as HFpEF proxy, while 11 patients had Normal LV physiology. Utilising principal component analysis, the gene expression data clustered into two groups, corresponding to HFpEF proxy and Normal physiology, and 743 differentially expressed genes were identified. The associated top biological functions were cardiac muscle contraction, oxidative phosphorylation, cellular remodelling and matrix organisation. Our results also indicate that upstream regulatory events, including inhibition of transcription factors STAT4, SRF and TP53, and activation of transcription repressors HEY2 and KDM5A, could provide explanatory mechanisms to observed gene expression differences and ultimately cardiac dysfunction in the HFpEF proxy group. <br> Sequencing data from clinical patients fall under GDPR regulations of sharing of personal data and will be made available through EGA-SE.
Project description:Inflammation, fibrosis and metabolic stress critically promote heart failure with preserved ejection fraction (HFpEF). Exposure to high-fat diet and nitric oxide synthase inhibitor N[w]-nitro-l-arginine methyl ester (L-NAME) recapitulate features of HFpEF in mice. To identify disease specific traits during adverse remodeling, we profiled interstitial cells in early murine HFpEF using single-cell RNAseq (scRNAseq). Diastolic dysfunction and perivascular fibrosis were accompanied by an activation of cardiac fibroblast and macrophage subsets. Integration of fibroblasts from HFpEF with two murine models for heart failure with reduced ejection fraction (HFrEF) identified a catalog of conserved fibroblast phenotypes across mouse models. Moreover, HFpEF specific characteristics included induced metabolic, hypoxic and inflammatory transcription factors and pathways, including enhanced expression of Angiopoietin-like 4 (Angptl4) next to basement membrane compounds, such as collagen IV (Col4a1). Fibroblast activation was further dissected into transcriptional and compositional shifts and thereby highly responsive cell states for each HF model were identified. In contrast to HFrEF, where myofibroblast and matrifibrocyte activation were crucial features, we found that these cell states played a subsidiary role in early HFpEF. These disease-specific fibroblast signatures were corroborated in human myocardial bulk transcriptomes. Furthermore, we identified a potential cross-talk between macrophages and fibroblasts via SPP1 and TNFɑ with estimated fibroblast target genes including Col4a1 and Angptl4. Treatment with recombinant ANGPTL4 ameliorated the murine HFpEF phenotype and diastolic dysfunction by reducing collagen IV deposition from fibroblasts in vivo and in vitro. In line, ANGPTL4, was elevated in plasma samples of HFpEF patients and particularly high levels associated with a preserved global longitudinal strain. Taken together, our study provides a comprehensive characterization of molecular fibroblast activation patterns in murine HFpEF, as well as the identification of Angiopoietin-like 4 as central mechanistic regulator with protective effects.
Project description:As patients with heart failure with preserved ejection fraction (HFpEF) present with multiple comorbidities, we hypothesized, that metabolic syndrome in aging animals could lead to the development of diastolic dysfunction and HFpEF. HFpEF is a common complex morbid syndrome for which there are currently little evidence-based therapies. Obesity-prone rats were exposed to high-fat diet and compared to obesity-resistant rats fed with standard chow. Phenotyping of metabolic syndrome, associated with echocardiographic and cardiac hemodynamic measurements, was performed after 4 and 12 months. Blood and myocardial tissue sampling were performed for pathobiological evaluation. High-fat diet in obesity-prone rats elicited metabolic syndrome, characterized by increased body and abdominal fat weights, glucose intolerance and hyperlipidemia, as well as increased left ventricular (LV) systolic pressure (after 12 months). This was associated with LV diastolic dysfunction (assessed by increased LV end-diastolic pressure) and pulmonary hypertension (assessed by increased right ventricular systolic pressure). Echocardiography revealed significant concentric LV hypertrophy, while LV ejection fraction was preserved. LV remodeling was associated with cardiomyocyte hypertrophy, as well as myocardial and perivascular fibrosis. Circulating levels of soluble ST2 markedly increased in rats with HFpEF, while plasma NT-proBNP levels decreased. RNA-sequencing analysis identified clusters of genes implicated in fatty acid metabolism and calcium-dependent contraction as upregulated pathways in the myocardium of rats with HFpEF. High-fat diet during 12 months in obesity-prone rats led to the development of a relevant preclinical model of HFpEF with multiple comorbidities, suitable for investigating novel therapeutic interventions.