RESUMO
Quantitative subcellular metabolomic measurements can explain the roles of metabolites in cellular processes but are subject to multiple confounding factors. We developed stable isotope labeling of essential nutrients in cell culture-subcellular fractionation (SILEC-SF), which uses isotope-labeled internal standard controls that are present throughout fractionation and processing to quantify acyl-coenzyme A (acyl-CoA) thioesters in subcellular compartments by liquid chromatography-mass spectrometry. We tested SILEC-SF in a range of sample types and examined the compartmentalized responses to oxygen tension, cellular differentiation, and nutrient availability. Application of SILEC-SF to the challenging analysis of the nuclear compartment revealed a nuclear acyl-CoA profile distinct from that of the cytosol, with notable nuclear enrichment of propionyl-CoA. Using isotope tracing, we identified the branched chain amino acid isoleucine as a major metabolic source of nuclear propionyl-CoA and histone propionylation, thus revealing a new mechanism of crosstalk between metabolism and the epigenome.
Assuntos
Acil Coenzima A/metabolismo , Compartimento Celular , Núcleo Celular/metabolismo , Metabolismo Energético , Histonas/metabolismo , Metabolômica , Processamento de Proteína Pós-Traducional , Animais , Diferenciação Celular , Cromatografia Líquida , Citosol/metabolismo , Epigênese Genética , Células Hep G2 , Humanos , Isoleucina , Metaboloma , Camundongos , Mitocôndrias/metabolismo , Oxigênio/metabolismo , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Heart failure encompasses a heterogeneous set of clinical features that converge on impaired cardiac contractile function1,2 and presents a growing public health concern. Previous work has highlighted changes in both transcription and protein expression in failing hearts3,4, but may overlook molecular changes in less prevalent cell types. Here we identify extensive molecular alterations in failing hearts at single-cell resolution by performing single-nucleus RNA sequencing of nearly 600,000 nuclei in left ventricle samples from 11 hearts with dilated cardiomyopathy and 15 hearts with hypertrophic cardiomyopathy as well as 16 non-failing hearts. The transcriptional profiles of dilated or hypertrophic cardiomyopathy hearts broadly converged at the tissue and cell-type level. Further, a subset of hearts from patients with cardiomyopathy harbour a unique population of activated fibroblasts that is almost entirely absent from non-failing samples. We performed a CRISPR-knockout screen in primary human cardiac fibroblasts to evaluate this fibrotic cell state transition; knockout of genes associated with fibroblast transition resulted in a reduction of myofibroblast cell-state transition upon TGFß1 stimulation for a subset of genes. Our results provide insights into the transcriptional diversity of the human heart in health and disease as well as new potential therapeutic targets and biomarkers for heart failure.
Assuntos
Cardiomiopatia Dilatada , Cardiomiopatia Hipertrófica , Núcleo Celular , Perfilação da Expressão Gênica , Insuficiência Cardíaca , Análise de Célula Única , Sistemas CRISPR-Cas , Cardiomiopatia Dilatada/genética , Cardiomiopatia Dilatada/patologia , Cardiomiopatia Hipertrófica/genética , Cardiomiopatia Hipertrófica/patologia , Estudos de Casos e Controles , Núcleo Celular/genética , Células Cultivadas , Técnicas de Inativação de Genes , Insuficiência Cardíaca/genética , Insuficiência Cardíaca/patologia , Ventrículos do Coração/metabolismo , Ventrículos do Coração/patologia , Humanos , Miocárdio/metabolismo , Miocárdio/patologia , Miofibroblastos/metabolismo , Miofibroblastos/patologia , RNA-Seq , Transcrição Gênica , Fator de Crescimento Transformador beta1RESUMO
BACKGROUND: Cardiac hypertrophy increases demands on protein folding, which causes an accumulation of misfolded proteins in the endoplasmic reticulum (ER). These misfolded proteins can be removed by the adaptive retrotranslocation, polyubiquitylation, and a proteasome-mediated degradation process, ER-associated degradation (ERAD), which, as a biological process and rate, has not been studied in vivo. To investigate a role for ERAD in a pathophysiological model, we examined the function of the functional initiator of ERAD, valosin-containing protein-interacting membrane protein (VIMP), positing that VIMP would be adaptive in pathological cardiac hypertrophy in mice. METHODS: We developed a new method involving cardiac myocyte-specific adeno-associated virus serovar 9-mediated expression of the canonical ERAD substrate, TCRα, to measure the rate of ERAD, ie, ERAD flux, in the heart in vivo. Adeno-associated virus serovar 9 was also used to either knock down or overexpress VIMP in the heart. Then mice were subjected to transverse aortic constriction to induce pressure overload-induced cardiac hypertrophy. RESULTS: ERAD flux was slowed in both human heart failure and mice after transverse aortic constriction. Surprisingly, although VIMP adaptively contributes to ERAD in model cell lines, in the heart, VIMP knockdown increased ERAD and ameliorated transverse aortic constriction-induced cardiac hypertrophy. Coordinately, VIMP overexpression exacerbated cardiac hypertrophy, which was dependent on VIMP engaging in ERAD. Mechanistically, we found that the cytosolic protein kinase SGK1 (serum/glucocorticoid regulated kinase 1) is a major driver of pathological cardiac hypertrophy in mice subjected to transverse aortic constriction, and that VIMP knockdown decreased the levels of SGK1, which subsequently decreased cardiac pathology. We went on to show that although it is not an ER protein, and resides outside of the ER, SGK1 is degraded by ERAD in a noncanonical process we call ERAD-Out. Despite never having been in the ER, SGK1 is recognized as an ERAD substrate by the ERAD component DERLIN1, and uniquely in cardiac myocytes, VIMP displaces DERLIN1 from initiating ERAD, which decreased SGK1 degradation and promoted cardiac hypertrophy. CONCLUSIONS: ERAD-Out is a new preferentially favored noncanonical form of ERAD that mediates the degradation of SGK1 in cardiac myocytes, and in so doing is therefore an important determinant of how the heart responds to pathological stimuli, such as pressure overload.
Assuntos
Cardiomegalia , Degradação Associada com o Retículo Endoplasmático , Animais , Humanos , Camundongos , Cardiomegalia/metabolismo , Retículo Endoplasmático/metabolismo , Degradação Associada com o Retículo Endoplasmático/fisiologia , Miócitos Cardíacos/metabolismo , Resposta a Proteínas não Dobradas/fisiologiaRESUMO
BACKGROUND: The human heart primarily metabolizes fatty acids, and this decreases as alternative fuel use rises in heart failure with reduced ejection fraction (HFrEF). Patients with severe obesity and diabetes are thought to have increased myocardial fatty acid metabolism, but whether this is found in those who also have heart failure with preserved ejection fraction (HFpEF) is unknown. METHODS: Plasma and endomyocardial biopsies were obtained from HFpEF (n=38), HFrEF (n=30), and nonfailing donor controls (n=20). Quantitative targeted metabolomics measured organic acids, amino acids, and acylcarnitines in myocardium (72 metabolites) and plasma (69 metabolites). The results were integrated with reported RNA sequencing data. Metabolomics were analyzed using agnostic clustering tools, Kruskal-Wallis test with Dunn test, and machine learning. RESULTS: Agnostic clustering of myocardial but not plasma metabolites separated disease groups. Despite more obesity and diabetes in HFpEF versus HFrEF (body mass index, 39.8 kg/m2 versus 26.1 kg/m2; diabetes, 70% versus 30%; both P<0.0001), medium- and long-chain acylcarnitines (mostly metabolites of fatty acid oxidation) were markedly lower in myocardium from both heart failure groups versus control. In contrast, plasma levels were no different or higher than control. Gene expression linked to fatty acid metabolism was generally lower in HFpEF versus control. Myocardial pyruvate was higher in HFpEF whereas the tricarboxylic acid cycle intermediates succinate and fumarate were lower, as were several genes controlling glucose metabolism. Non-branched-chain and branched-chain amino acids (BCAA) were highest in HFpEF myocardium, yet downstream BCAA metabolites and genes controlling BCAA metabolism were lower. Ketone levels were higher in myocardium and plasma of patients with HFrEF but not HFpEF. HFpEF metabolomic-derived subgroups were differentiated by only a few differences in BCAA metabolites. CONCLUSIONS: Despite marked obesity and diabetes, HFpEF myocardium exhibited lower fatty acid metabolites compared with HFrEF. Ketones and metabolites of the tricarboxylic acid cycle and BCAA were also lower in HFpEF, suggesting insufficient use of alternative fuels. These differences were not detectable in plasma and challenge conventional views of myocardial fuel use in HFpEF with marked diabetes and obesity and suggest substantial fuel inflexibility in this syndrome.
Assuntos
Diabetes Mellitus , Insuficiência Cardíaca , Humanos , Insuficiência Cardíaca/metabolismo , Volume Sistólico , Miocárdio/metabolismo , Diabetes Mellitus/patologia , Obesidade/patologia , Ácidos GraxosRESUMO
AIMS: Genetic hypertrophic cardiomyopathy (HCM) is caused by mutations in sarcomere protein-encoding genes (i.e. genotype-positive HCM). In an increasing number of patients, HCM occurs in the absence of a mutation (i.e. genotype-negative HCM). Mitochondrial dysfunction is thought to be a key driver of pathological remodelling in HCM. Reports of mitochondrial respiratory function and specific disease-modifying treatment options in patients with HCM are scarce. METHODS AND RESULTS: Respirometry was performed on septal myectomy tissue from patients with HCM (n = 59) to evaluate oxidative phosphorylation and fatty acid oxidation. Mitochondrial dysfunction was most notably reflected by impaired NADH-linked respiration. In genotype-negative patients, but not genotype-positive patients, NADH-linked respiration was markedly depressed in patients with an indexed septal thickness ≥10 compared with <10. Mitochondrial dysfunction was not explained by reduced abundance or fragmentation of mitochondria, as evaluated by transmission electron microscopy. Rather, improper organization of mitochondria relative to myofibrils (expressed as a percentage of disorganized mitochondria) was strongly associated with mitochondrial dysfunction. Pre-incubation with the cardiolipin-stabilizing drug elamipretide and raising mitochondrial NAD+ levels both boosted NADH-linked respiration. CONCLUSION: Mitochondrial dysfunction is explained by cardiomyocyte architecture disruption and is linked to septal hypertrophy in genotype-negative HCM. Despite severe myocardial remodelling mitochondria were responsive to treatments aimed at restoring respiratory function, eliciting the mitochondria as a drug target to prevent and ameliorate cardiac disease in HCM. Mitochondria-targeting therapy may particularly benefit genotype-negative patients with HCM, given the tight link between mitochondrial impairment and septal thickening in this subpopulation.
Assuntos
Cardiomiopatia Hipertrófica , Miócitos Cardíacos , Humanos , Miócitos Cardíacos/patologia , NAD/genética , Cardiomiopatia Hipertrófica/genética , Mutação , Mitocôndrias Cardíacas/patologia , RespiraçãoRESUMO
Osteogenesis imperfecta (OI) is an extracellular matrix disorder characterized by defects in collagen-1 transport or synthesis, resulting in bone abnormalities. Although reduced collagen in OI hearts has been associated with reduced myocardial stiffness and left ventricular remodeling, its impact on cardiomyocyte (CM) function has not been studied. Here, we explore the tissue-level and CM-level properties of a heart from a deceased organ donor with OI type I. Proteomics and histology confirmed strikingly low expression of collagen 1. Trabecular stretch confirmed low stiffness on the tissue level. However, CMs retained normal viscoelastic properties as revealed by nanoindentation. Interestingly, OI CMs were hypercontractile relative to nonfailing controls after 24 h of culture. In response to 48 h of culture on surfaces with physiological (10 kPa) and pathological (50 kPa) stiffness, OI CMs demonstrated a greater reduction in contractility than nonfailing CMs, suggesting that OI CMs may have an impaired stress response. Levels of detyrosinated α-tubulin, known to be responsive to extracellular stiffness, were reduced in OI CMs. Together these data confirm multiple CM-level adaptations to low stiffness that extend our understanding of OI in the heart and how CMs respond to extracellular stiffness.NEW & NOTEWORTHY In a rare donation of a heart from an individual with osteogenesis imperfecta (OI), we explored cardiomyocyte (CM) adaptations to low stiffness. This represents the first assessment of cardiomyocyte mechanics in OI. The data reveal the hypercontractility of OI CMs with rapid rundown when exposed to acute stiffness challenges, extending our understanding of OI. These data demonstrate that the impact of OI on myocardial mechanics includes cardiomyocyte adaptations beyond known direct effects on the extracellular matrix.
Assuntos
Osteogênese Imperfeita , Humanos , Adulto , Osteogênese Imperfeita/metabolismo , Osteogênese Imperfeita/patologia , Miócitos Cardíacos/metabolismo , Colágeno/metabolismo , Colágeno Tipo I/metabolismo , Matriz Extracelular/metabolismo , OsteogêneseRESUMO
BACKGROUND: Mural cells in ascending aortic aneurysms undergo phenotypic changes that promote extracellular matrix destruction and structural weakening. To explore this biology, we analyzed the transcriptional features of thoracic aortic tissue. METHODS: Single-nuclear RNA sequencing was performed on 13 samples from human donors, 6 with thoracic aortic aneurysm, and 7 without aneurysm. Individual transcriptomes were then clustered based on transcriptional profiles. Clusters were used for between-disease differential gene expression analyses, subcluster analysis, and analyzed for intersection with genetic aortic trait data. RESULTS: We sequenced 71 689 nuclei from human thoracic aortas and identified 14 clusters, aligning with 11 cell types, predominantly vascular smooth muscle cells (VSMCs) consistent with aortic histology. With unbiased methodology, we found 7 vascular smooth muscle cell and 6 fibroblast subclusters. Differentially expressed genes analysis revealed a vascular smooth muscle cell group accounting for the majority of differential gene expression. Fibroblast populations in aneurysm exhibit distinct behavior with almost complete disappearance of quiescent fibroblasts. Differentially expressed genes were used to prioritize genes at aortic diameter and distensibility genome-wide association study loci highlighting the genes JUN, LTBP4 (latent transforming growth factor beta-binding protein 1), and IL34 (interleukin 34) in fibroblasts, ENTPD1, PDLIM5 (PDZ and LIM domain 5), ACTN4 (alpha-actinin-4), and GLRX in vascular smooth muscle cells, as well as LRP1 in macrophage populations. CONCLUSIONS: Using nuclear RNA sequencing, we describe the cellular diversity of healthy and aneurysmal human ascending aorta. Sporadic aortic aneurysm is characterized by differential gene expression within known cellular classes rather than by the appearance of novel cellular forms. Single-nuclear RNA sequencing of aortic tissue can be used to prioritize genes at aortic trait loci.
Assuntos
Aneurisma da Aorta Torácica , Aneurisma Aórtico , Humanos , Estudo de Associação Genômica Ampla , Músculo Liso Vascular/metabolismo , Actinina/genética , RNA Nuclear/metabolismo , Aorta/patologia , Miócitos de Músculo Liso/metabolismo , Aneurisma da Aorta Torácica/patologia , Aneurisma Aórtico/metabolismo , Análise de Sequência de RNA , Fator de Crescimento Transformador beta/metabolismoRESUMO
Anabolic metabolism of carbon in mammals is mediated via the one- and two-carbon carriers S-adenosyl methionine and acetyl-coenzyme A. In contrast, anabolic metabolism of three-carbon units via propionate has not been shown to extensively occur. Mammals are primarily thought to oxidize the three-carbon short chain fatty acid propionate by shunting propionyl-CoA to succinyl-CoA for entry into the TCA cycle. Here, we found that this may not be absolute as, in mammals, one nonoxidative fate of propionyl-CoA is to condense to two three-carbon units into a six-carbon trans-2-methyl-2-pentenoyl-CoA (2M2PE-CoA). We confirmed this reaction pathway using purified protein extracts provided limited substrates and verified the product via LC-MS using a synthetic standard. In whole-body in vivo stable isotope tracing following infusion of 13C-labeled valine at steady state, 2M2PE-CoA was found to form via propionyl-CoA in multiple murine tissues, including heart, kidney, and to a lesser degree, in brown adipose tissue, liver, and tibialis anterior muscle. Using ex vivo isotope tracing, we found that 2M2PE-CoA also formed in human myocardial tissue incubated with propionate to a limited extent. While the complete enzymology of this pathway remains to be elucidated, these results confirm the in vivo existence of at least one anabolic three- to six-carbon reaction conserved in humans and mice that utilizes propionate.
Assuntos
Carbono , Propionatos , Acetilcoenzima A/metabolismo , Acil Coenzima A/metabolismo , Animais , Carbono/metabolismo , Fígado/metabolismo , Camundongos , OxirreduçãoRESUMO
BACKGROUND: The human heart requires a complex ensemble of specialized cell types to perform its essential function. A greater knowledge of the intricate cellular milieu of the heart is critical to increase our understanding of cardiac homeostasis and pathology. As recent advances in low-input RNA sequencing have allowed definitions of cellular transcriptomes at single-cell resolution at scale, we have applied these approaches to assess the cellular and transcriptional diversity of the nonfailing human heart. METHODS: Microfluidic encapsulation and barcoding was used to perform single nuclear RNA sequencing with samples from 7 human donors, selected for their absence of overt cardiac disease. Individual nuclear transcriptomes were then clustered based on transcriptional profiles of highly variable genes. These clusters were used as the basis for between-chamber and between-sex differential gene expression analyses and intersection with genetic and pharmacologic data. RESULTS: We sequenced the transcriptomes of 287 269 single cardiac nuclei, revealing 9 major cell types and 20 subclusters of cell types within the human heart. Cellular subclasses include 2 distinct groups of resident macrophages, 4 endothelial subtypes, and 2 fibroblast subsets. Comparisons of cellular transcriptomes by cardiac chamber or sex reveal diversity not only in cardiomyocyte transcriptional programs but also in subtypes involved in extracellular matrix remodeling and vascularization. Using genetic association data, we identified strong enrichment for the role of cell subtypes in cardiac traits and diseases. Intersection of our data set with genes on cardiac clinical testing panels and the druggable genome reveals striking patterns of cellular specificity. CONCLUSIONS: Using large-scale single nuclei RNA sequencing, we defined the transcriptional and cellular diversity in the normal human heart. Our identification of discrete cell subtypes and differentially expressed genes within the heart will ultimately facilitate the development of new therapeutics for cardiovascular diseases.
Assuntos
Miocárdio/citologia , Transcrição Gênica , Adipócitos/metabolismo , Adulto , Idoso , Fármacos Cardiovasculares/farmacologia , Fármacos Cardiovasculares/uso terapêutico , Células Endoteliais/classificação , Células Endoteliais/metabolismo , Fibroblastos/classificação , Fibroblastos/metabolismo , Ontologia Genética , Coração/inervação , Átrios do Coração/citologia , Cardiopatias/tratamento farmacológico , Ventrículos do Coração/citologia , Homeostase , Humanos , Subpopulações de Linfócitos/metabolismo , Macrófagos/classificação , Macrófagos/metabolismo , Técnicas Analíticas Microfluídicas , Pessoa de Meia-Idade , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , Miócitos de Músculo Liso/metabolismo , Pericitos/metabolismo , RNA-Seq , Caracteres Sexuais , Análise de Célula Única , TranscriptomaRESUMO
AIMS: C-type natriuretic peptide (CNP) is an essential endothelium-derived signalling species that governs vascular homoeostasis; CNP is also expressed in the heart but an intrinsic role for the peptide in cardiac function is not established. Herein, we employ unique transgenic strains with cell-specific deletion of CNP to define a central (patho)physiological capacity of CNP in maintaining heart morphology and contractility. METHODS AND RESULTS: Cardiac structure and function were explored in wild type (WT), cardiomyocyte (cmCNP-/-), endothelium (ecCNP-/-), and fibroblast (fbCNP-/-)-specific CNP knockout mice, and global natriuretic peptide receptor (NPR)-B-/-, and NPR-C-/- animals at baseline and in experimental models of myocardial infarction and heart failure (HF). Endothelium-specific deletion of CNP resulted in impaired coronary responsiveness to endothelium-dependent- and flow-mediated-dilatation; changes mirrored in NPR-C-/- mice. Ex vivo, global ischaemia resulted in larger infarcts and diminished functional recovery in cmCNP-/- and NPR-C-/-, but not ecCNP-/-, vs. WT. The cardiac phenotype of cmCNP-/-, fbCNP-/-, and NPR-C-/- (but not ecCNP-/- or NPR-B-/-) mice was more severe in pressure overload- and sympathetic hyperactivation-induced HF compared with WT; these adverse effects were rescued by pharmacological CNP administration in WT, but not NPR-C-/-, mice. At a molecular level, CNP/NPR-C signalling is impaired in human HF but attenuates activation of well-validated pro-hypertrophic and pro-fibrotic pathways. CONCLUSION: C-type natriuretic peptide of cardiomyocyte, endothelial and fibroblast origins co-ordinates and preserves cardiac structure, function, and coronary vasoreactivity via activation of NPR-C. Targeting NPR-C may prove an innovative approach to treating HF and ischaemic cardiovascular disorders.
Assuntos
Insuficiência Cardíaca , Peptídeo Natriurético Tipo C , Animais , Fator Natriurético Atrial , Camundongos , Camundongos Knockout , Miócitos Cardíacos , Peptídeo Natriurético Tipo C/genética , Transdução de SinaisRESUMO
Coronary microvascular dysfunction combined with maladaptive cardiomyocyte morphology and energetics is a major contributor to heart failure advancement. Thus, dually enhancing cardiac angiogenesis and targeting cardiomyocyte function to slow, or reverse, the development of heart failure is a logical step towards improved therapy. We present evidence for the potential to repurpose a former anti-cancer Arg-Gly-Asp (RGD)-mimetic pentapeptide, cilengitide, here used at low doses. Cilengitide targets αvß3 integrin and this protein is upregulated in human dilated and ischaemic cardiomyopathies. Treatment of mice after abdominal aortic constriction (AAC) surgery with low-dose cilengitide (ldCil) enhances coronary angiogenesis and directly affects cardiomyocyte hypertrophy with an associated reduction in disease severity. At a molecular level, ldCil treatment has a direct effect on cardiac endothelial cell transcriptomic profiles, with a significant enhancement of pro-angiogenic signalling pathways, corroborating the enhanced angiogenic phenotype after ldCil treatment. Moreover, ldCil treatment of Angiotensin II-stimulated AngII-stimulated cardiomyocytes significantly restores transcriptomic profiles similar to those found in normal human heart. The significance of this finding is enhanced by transcriptional similarities between AngII-treated cardiomyocytes and failing human hearts. Taken together, our data provide evidence supporting a possible new strategy for improved heart failure treatment using low-dose RGD-mimetics with relevance to human disease. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
Assuntos
Cardiomegalia/tratamento farmacológico , Fármacos Cardiovasculares/farmacologia , Reposicionamento de Medicamentos , Insuficiência Cardíaca/tratamento farmacológico , Integrina alfaVbeta3/antagonistas & inibidores , Miócitos Cardíacos/efeitos dos fármacos , Venenos de Serpentes/farmacologia , Angiotensina II/farmacologia , Animais , Cardiomegalia/genética , Cardiomegalia/metabolismo , Cardiomegalia/fisiopatologia , Estudos de Casos e Controles , Células Cultivadas , Modelos Animais de Doenças , Fibrose , Regulação da Expressão Gênica , Insuficiência Cardíaca/genética , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/fisiopatologia , Humanos , Integrina alfaVbeta3/metabolismo , Masculino , Camundongos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Neovascularização Fisiológica/efeitos dos fármacos , Recuperação de Função Fisiológica , Transdução de Sinais , TranscriptomaRESUMO
BACKGROUND: The failing human heart is characterized by metabolic abnormalities, but these defects remains incompletely understood. In animal models of heart failure there is a switch from a predominance of fatty acid utilization to the more oxygen-sparing carbohydrate metabolism. Recent studies have reported decreases in myocardial lipid content, but the inclusion of diabetic and nondiabetic patients obscures the distinction of adaptations to metabolic derangements from adaptations to heart failure per se. METHODS AND RESULTS: We performed both unbiased and targeted myocardial lipid surveys using liquid chromatography-mass spectroscopy in nondiabetic, lean, predominantly nonischemic, advanced heart failure patients at the time of heart transplantation or left ventricular assist device implantation. We identified significantly decreased concentrations of the majority of myocardial lipid intermediates, including long-chain acylcarnitines, the primary subset of energetic lipid substrate for mitochondrial fatty acid oxidation. We report for the first time significantly reduced levels of intermediate and anaplerotic acyl-coenzyme A (CoA) species incorporated into the Krebs cycle, whereas the myocardial concentration of acetyl-CoA was significantly increased in end-stage heart failure. In contrast, we observed an increased abundance of ketogenic ß-hydroxybutyryl-CoA, in association with increased myocardial utilization of ß-hydroxybutyrate. We observed a significant increase in the expression of the gene encoding succinyl-CoA:3-oxoacid-CoA transferase, the rate-limiting enzyme for myocardial oxidation of ß-hydroxybutyrate and acetoacetate. CONCLUSIONS: These findings indicate increased ketone utilization in the severely failing human heart independent of diabetes mellitus, and they support the role of ketone bodies as an alternative fuel and myocardial ketone oxidation as a key metabolic adaptation in the failing human heart.
Assuntos
Progressão da Doença , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/metabolismo , Cetonas/metabolismo , Metabolismo dos Lipídeos/fisiologia , Miocárdio/metabolismo , Adulto , Idoso , Estudos de Casos e Controles , Doença Crônica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Miocárdio/patologiaAssuntos
Infecções por Coronavirus/patologia , Miocardite/diagnóstico , Miocárdio/metabolismo , Peptidil Dipeptidase A/genética , Pneumonia Viral/patologia , Enzima de Conversão de Angiotensina 2 , Betacoronavirus/isolamento & purificação , Betacoronavirus/patogenicidade , COVID-19 , Cardiomiopatia Dilatada/genética , Cardiomiopatia Dilatada/patologia , Cardiomiopatia Hipertrófica/genética , Cardiomiopatia Hipertrófica/patologia , Catepsina L/genética , Catepsina L/metabolismo , Infecções por Coronavirus/complicações , Infecções por Coronavirus/virologia , Ventrículos do Coração/metabolismo , Humanos , Miocardite/etiologia , Pandemias , Peptidil Dipeptidase A/química , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/complicações , Pneumonia Viral/virologia , Inibidores de Proteases/farmacologia , RNA-Seq , SARS-CoV-2 , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismo , Regulação para Cima/efeitos dos fármacosRESUMO
Recent studies suggest that metabolic dysregulation in patients with heart failure might contribute to myocardial contractile dysfunction. To understand the correlation between function and energy metabolism, we studied the impact of different fuel substrates on human nonfailing or failing cardiomyocytes. Consistent with the concept of metabolic flexibility, nonfailing myocytes exhibited excellent contractility in all fuels provided. However, impaired contractility was observed in failing myocytes when carbohydrates alone were used but was improved when additional substrates were added. This study demonstrates the functional significance of fuel utilization shifts in failing human cardiomyocytes.
RESUMO
Differentiation of cardiac fibroblasts to myofibroblasts is necessary for matrix remodeling and fibrosis in heart failure. We previously reported that mitochondrial calcium signaling drives α-ketoglutarate-dependent histone demethylation, promoting myofibroblast formation. Here we investigate the role of ATP-citrate lyase (ACLY), a key enzyme for acetyl-CoA biosynthesis, in histone acetylation regulating myofibroblast fate and persistence in cardiac fibrosis. We show that inactivation of ACLY prevents myofibroblast differentiation and reverses myofibroblasts towards quiescence. Genetic deletion of Acly in post-activated myofibroblasts prevents fibrosis and preserves cardiac function in pressure-overload heart failure. TGFß stimulation enhances ACLY nuclear localization and ACLY-SMAD2/3 interaction, and increases H3K27ac at fibrotic gene loci. Pharmacological inhibition of ACLY or forced nuclear expression of a dominant-negative ACLY mutant prevents myofibroblast formation and H3K27ac. Our data indicate that nuclear ACLY activity is necessary for myofibroblast differentiation and persistence by maintaining histone acetylation at TGFß-induced myofibroblast genes. These findings provide targets to prevent and reverse pathological fibrosis.
Assuntos
ATP Citrato (pro-S)-Liase , Diferenciação Celular , Fibrose , Histonas , Miofibroblastos , Proteína Smad2 , Miofibroblastos/metabolismo , Miofibroblastos/efeitos dos fármacos , ATP Citrato (pro-S)-Liase/metabolismo , ATP Citrato (pro-S)-Liase/genética , Animais , Fibrose/metabolismo , Diferenciação Celular/efeitos dos fármacos , Histonas/metabolismo , Proteína Smad2/metabolismo , Proteína Smad2/genética , Acetilação/efeitos dos fármacos , Núcleo Celular/metabolismo , Núcleo Celular/efeitos dos fármacos , Proteína Smad3/metabolismo , Proteína Smad3/genética , Células Cultivadas , Cromatina/metabolismo , Camundongos Knockout , Fator de Crescimento Transformador beta/metabolismo , Modelos Animais de Doenças , Transdução de Sinais , Camundongos Endogâmicos C57BL , Masculino , Camundongos , Regulação da Expressão Gênica/efeitos dos fármacosRESUMO
Heart failure with preserved ejection fraction (HFpEF) is a complex syndrome associated with increased myocardial stiffness and cardiac filling abnormalities. Prior studies implicated increased α-tubulin detyrosination, which is catalyzed by the vasohibin enzymes, as a contributor to increased stabilization of the cardiomyocyte microtubule network (MTN) and stiffness in failing human hearts. We explored whether increased MTN detyrosination contributed to impaired diastolic function in the ZSF1 obese rat model of HFpEF and designed a small-molecule vasohibin inhibitor to ablate MTN detyrosination in vivo. Compared with ZSF1 lean and Wistar Kyoto rats, obese rats exhibited increased tubulin detyrosination concomitant with diastolic dysfunction, left atrial enlargement, and cardiac hypertrophy with a preserved left ventricle ejection fraction, consistent with an HFpEF phenotype. Ex vivo myocardial phenotyping assessed cardiomyocyte mechanics and contractility. Vasohibin inhibitor treatment of isolated cardiomyocytes from obese rats resulted in reduced stiffness and faster relaxation. Acute in vivo treatment with vasohibin inhibitor improved diastolic relaxation in ZSF1 obese rats compared with ZSF1 lean and Wistar Kyoto rats. Vasohibin inhibition also improved relaxation in isolated human cardiomyocytes from both failing and nonfailing hearts. Our data suggest the therapeutic potential for vasohibin inhibition to reduce myocardial stiffness and improve relaxation in HFpEF.
Assuntos
Modelos Animais de Doenças , Insuficiência Cardíaca , Miócitos Cardíacos , Volume Sistólico , Animais , Humanos , Masculino , Ratos , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/antagonistas & inibidores , Diástole/efeitos dos fármacos , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/fisiopatologia , Insuficiência Cardíaca/patologia , Miocárdio/patologia , Miocárdio/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Obesidade/tratamento farmacológico , Obesidade/fisiopatologia , Ratos Endogâmicos WKY , Volume Sistólico/efeitos dos fármacos , Tubulina (Proteína)/metabolismoRESUMO
BACKGROUND: Hypertrophic cardiomyopathy (HCM) is caused by sarcomere gene mutations (genotype-positive HCM) in ≈50% of patients and occurs in the absence of mutations (genotype-negative HCM) in the other half of patients. We explored how alterations in the metabolomic and lipidomic landscape are involved in cardiac remodeling in both patient groups. METHODS: We performed proteomics, metabolomics, and lipidomics on myectomy samples (genotype-positive N=19; genotype-negative N=22; and genotype unknown N=6) from clinically well-phenotyped patients with HCM and on cardiac tissue samples from sex- and age-matched and body mass index-matched nonfailing donors (N=20). These data sets were integrated to comprehensively map changes in lipid-handling and energy metabolism pathways. By linking metabolomic and lipidomic data to variability in clinical data, we explored patient group-specific associations between cardiac and metabolic remodeling. RESULTS: HCM myectomy samples exhibited (1) increased glucose and glycogen metabolism, (2) downregulation of fatty acid oxidation, and (3) reduced ceramide formation and lipid storage. In genotype-negative patients, septal hypertrophy and diastolic dysfunction correlated with lowering of acylcarnitines, redox metabolites, amino acids, pentose phosphate pathway intermediates, purines, and pyrimidines. In contrast, redox metabolites, amino acids, pentose phosphate pathway intermediates, purines, and pyrimidines were positively associated with septal hypertrophy and diastolic impairment in genotype-positive patients. CONCLUSIONS: We provide novel insights into both general and genotype-specific metabolic changes in HCM. Distinct metabolic alterations underlie cardiac disease progression in genotype-negative and genotype-positive patients with HCM.
Assuntos
Cardiomiopatia Hipertrófica , Genótipo , Fenótipo , Humanos , Cardiomiopatia Hipertrófica/genética , Cardiomiopatia Hipertrófica/metabolismo , Cardiomiopatia Hipertrófica/patologia , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Miocárdio/metabolismo , Miocárdio/patologia , Metabolômica , Proteômica , Lipidômica , Metabolismo dos Lipídeos/genética , Sarcômeros/metabolismo , Sarcômeros/genética , Metabolismo Energético/genética , Idoso , MultiômicaRESUMO
Ischemic cardiomyopathy (ICM) is the leading cause of heart failure worldwide, yet the cellular and molecular signature of this disease is largely unclear. Using single-nucleus RNA sequencing (snRNA-seq) and integrated computational analyses, we profile the transcriptomes of over 99,000 human cardiac nuclei from the non-infarct region of the left ventricle of 7 ICM transplant recipients and 8 non-failing (NF) controls. We find the cellular composition of the ischemic heart is significantly altered, with decreased cardiomyocytes and increased proportions of lymphatic, angiogenic, and arterial endothelial cells in patients with ICM. We show that there is increased LAMININ signaling from endothelial cells to other cell types in ICM compared with NF. Finally, we find that the transcriptional changes that occur in ICM are similar to those in hypertrophic and dilated cardiomyopathies and that the mining of these combined datasets can identify druggable genes that could be used to target end-stage heart failure.
Assuntos
Cardiomiopatias , Cardiomiopatia Dilatada , Insuficiência Cardíaca , Isquemia Miocárdica , Humanos , Células Endoteliais/metabolismo , Isquemia Miocárdica/genética , Isquemia Miocárdica/metabolismo , Insuficiência Cardíaca/genética , Insuficiência Cardíaca/metabolismo , Análise de Sequência de RNA , Cardiomiopatias/genéticaRESUMO
Heart failure (HF) is a leading cause of mortality. Failing hearts undergo profound metabolic changes, but a comprehensive evaluation in humans is lacking. We integrate plasma and cardiac tissue metabolomics of 678 metabolites, genome-wide RNA-sequencing, and proteomic studies to examine metabolic status in 87 explanted human hearts from 39 patients with end-stage HF compared with 48 nonfailing donors. We confirm bioenergetic defects in human HF and reveal selective depletion of adenylate purines required for maintaining ATP levels. We observe substantial reductions in fatty acids and acylcarnitines in failing tissue, despite plasma elevations, suggesting defective import of fatty acids into cardiomyocytes. Glucose levels, in contrast, are elevated. Pyruvate dehydrogenase, which gates carbohydrate oxidation, is de-repressed, allowing increased lactate and pyruvate burning. Tricarboxylic acid cycle intermediates are significantly reduced. Finally, bioactive lipids are profoundly reprogrammed, with marked reductions in ceramides and elevations in lysoglycerophospholipids. These data unveil profound metabolic abnormalities in human failing hearts.
RESUMO
Pharmacologic activation of branched-chain amino acid (BCAA) catabolism is protective in models of heart failure (HF). How protection occurs remains unclear, although a causative block in cardiac BCAA oxidation is widely assumed. Here, we use in vivo isotope infusions to show that cardiac BCAA oxidation in fact increases, rather than decreases, in HF. Moreover, cardiac-specific activation of BCAA oxidation does not protect from HF even though systemic activation does. Lowering plasma and cardiac BCAAs also fails to confer significant protection, suggesting alternative mechanisms of protection. Surprisingly, activation of BCAA catabolism lowers blood pressure (BP), a known cardioprotective mechanism. BP lowering occurred independently of nitric oxide and reflected vascular resistance to adrenergic constriction. Mendelian randomization studies revealed that elevated plasma BCAAs portend higher BP in humans. Together, these data indicate that BCAA oxidation lowers vascular resistance, perhaps in part explaining cardioprotection in HF that is not mediated directly in cardiomyocytes.