RESUMO
The hexosamine biosynthetic pathway (HBP) generates uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) for glycan synthesis and O-linked GlcNAc (O-GlcNAc) protein modifications. Despite the established role of the HBP in metabolism and multiple diseases, regulation of the HBP remains largely undefined. Here, we show that spliced X-box binding protein 1 (Xbp1s), the most conserved signal transducer of the unfolded protein response (UPR), is a direct transcriptional activator of the HBP. We demonstrate that the UPR triggers HBP activation via Xbp1s-dependent transcription of genes coding for key, rate-limiting enzymes. We further establish that this previously unrecognized UPR-HBP axis is triggered in a variety of stress conditions. Finally, we demonstrate a physiologic role for the UPR-HBP axis by showing that acute stimulation of Xbp1s in heart by ischemia/reperfusion confers robust cardioprotection in part through induction of the HBP. Collectively, these studies reveal that Xbp1s couples the UPR to the HBP to protect cells under stress.
Assuntos
Vias Biossintéticas , Proteínas de Ligação a DNA/metabolismo , Hexosaminas/metabolismo , Fatores de Transcrição/metabolismo , Resposta a Proteínas não Dobradas , Animais , Glutamina-Frutose-6-Fosfato Transaminase (Isomerizante) , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Isquemia Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/metabolismo , Miócitos Cardíacos/metabolismo , Transferases de Grupos Nitrogenados/genética , Fatores de Transcrição de Fator Regulador X , Proteína 1 de Ligação a X-BoxRESUMO
A major factor in the progression to heart failure in humans is the inability of the adult heart to repair itself after injury. We recently demonstrated that the early postnatal mammalian heart is capable of regeneration following injury through proliferation of preexisting cardiomyocytes1,2 and that Meis1, a three amino acid loop extension (TALE) family homeodomain transcription factor, translocates to cardiomyocyte nuclei shortly after birth and mediates postnatal cell cycle arrest3. Here we report that Hoxb13 acts as a cofactor of Meis1 in postnatal cardiomyocytes. Cardiomyocyte-specific deletion of Hoxb13 can extend the postnatal window of cardiomyocyte proliferation and reactivate the cardiomyocyte cell cycle in the adult heart. Moreover, adult Meis1-Hoxb13 double-knockout hearts display widespread cardiomyocyte mitosis, sarcomere disassembly and improved left ventricular systolic function following myocardial infarction, as demonstrated by echocardiography and magnetic resonance imaging. Chromatin immunoprecipitation with sequencing demonstrates that Meis1 and Hoxb13 act cooperatively to regulate cardiomyocyte maturation and cell cycle. Finally, we show that the calcium-activated protein phosphatase calcineurin dephosphorylates Hoxb13 at serine-204, resulting in its nuclear localization and cell cycle arrest. These results demonstrate that Meis1 and Hoxb13 act cooperatively to regulate cardiomyocyte maturation and proliferation and provide mechanistic insights into the link between hyperplastic and hypertrophic growth of cardiomyocytes.
Assuntos
Calcineurina/metabolismo , Proliferação de Células , Proteínas de Homeodomínio/metabolismo , Proteína Meis1/metabolismo , Miócitos Cardíacos/citologia , Animais , Animais Recém-Nascidos , Feminino , Deleção de Genes , Regulação da Expressão Gênica , Coração/fisiologia , Proteínas de Homeodomínio/genética , Masculino , Camundongos , Miocárdio/citologia , Ligação Proteica , RegeneraçãoRESUMO
The physiological importance of cardiac myosin regulatory light chain (RLC) phosphorylation by its dedicated cardiac myosin light chain kinase has been established in both humans and mice. Constitutive RLC-phosphorylation, regulated by the balanced activities of cardiac myosin light chain kinase and myosin light chain phosphatase (MLCP), is fundamental to the biochemical and physiological properties of myofilaments. However, limited information is available on cardiac MLCP. In this study, we hypothesized that the striated muscle-specific MLCP regulatory subunit, MYPT2, targets the phosphatase catalytic subunit to cardiac myosin, contributing to the maintenance of cardiac function in vivo through the regulation of RLC-phosphorylation. To test this hypothesis, we generated a floxed-PPP1R12B mouse model crossed with a cardiac-specific Mer-Cre-Mer to conditionally ablate MYPT2 in adult cardiomyocytes. Immunofluorescence microscopy using the gene-ablated tissue as a control confirmed the localization of MYPT2 to regions where it overlaps with a subset of RLC. Biochemical analysis revealed an increase in RLC-phosphorylation in vivo. The loss of MYPT2 demonstrated significant protection against pressure overload-induced hypertrophy, as evidenced by heart weight, qPCR of hypertrophy-associated genes, measurements of myocyte diameters, and expression of ß-MHC protein. Furthermore, mantATP chase assays revealed an increased ratio of myosin heads distributed to the interfilament space in MYPT2-ablated heart muscle fibers, confirming that RLC-phosphorylation regulated by MLCP, enhances cardiac performance in vivo. Our findings establish MYPT2 as the regulatory subunit of cardiac MLCP, distinct from the ubiquitously expressed canonical smooth muscle MLCP. Targeting MYPT2 to increase cardiac RLC-phosphorylation in vivo may improve baseline cardiac performance, thereby attenuating pathological hypertrophy.
Assuntos
Miócitos Cardíacos , Quinase de Cadeia Leve de Miosina , Animais , Humanos , Camundongos , Hipertrofia/metabolismo , Miócitos Cardíacos/metabolismo , Cadeias Leves de Miosina/genética , Cadeias Leves de Miosina/metabolismo , Quinase de Cadeia Leve de Miosina/genética , Quinase de Cadeia Leve de Miosina/metabolismo , Fosfatase de Miosina-de-Cadeia-Leve/metabolismo , Fosforilação , Camundongos Endogâmicos C57BLRESUMO
BACKGROUND: Recent interest in understanding cardiomyocyte cell cycle has been driven by potential therapeutic applications in cardiomyopathy. However, despite recent advances, cardiomyocyte mitosis remains a poorly understood process. For example, it is unclear how sarcomeres are disassembled during mitosis to allow the abscission of daughter cardiomyocytes. METHODS: Here, we use a proteomics screen to identify adducin, an actin capping protein previously not studied in cardiomyocytes, as a regulator of sarcomere disassembly. We generated many adeno-associated viruses and cardiomyocyte-specific genetic gain-of-function models to examine the role of adducin in neonatal and adult cardiomyocytes in vitro and in vivo. RESULTS: We identify adducin as a regulator of sarcomere disassembly during mammalian cardiomyocyte mitosis. α/γ-adducins are selectively expressed in neonatal mitotic cardiomyocytes, and their levels decline precipitously thereafter. Cardiomyocyte-specific overexpression of various splice isoforms and phospho-isoforms of α-adducin in identified Thr445/Thr480 phosphorylation of a short isoform of α-adducin as a potent inducer of neonatal cardiomyocyte sarcomere disassembly. Concomitant overexpression of this α-adducin variant along with γ-adducin resulted in stabilization of the adducin complex and persistent sarcomere disassembly in adult mice, which is mediated by interaction with α-actinin. CONCLUSIONS: These results highlight an important mechanism for coordinating cytoskeletal morphological changes during cardiomyocyte mitosis.
RESUMO
BACKGROUND: Cardiomyocyte growth is coupled with active protein synthesis, which is one of the basic biological processes in living cells. However, it is unclear whether the unfolded protein response transducers and effectors directly take part in the control of protein synthesis. The connection between critical functions of the unfolded protein response in cellular physiology and requirements of multiple processes for cell growth prompted us to investigate the role of the unfolded protein response in cell growth and underlying molecular mechanisms. METHODS: Cardiomyocyte-specific inositol-requiring enzyme 1α (IRE1α) knockout and overexpression mouse models were generated to explore its function in vivo. Neonatal rat ventricular myocytes were isolated and cultured to evaluate the role of IRE1α in cardiomyocyte growth in vitro. Mass spectrometry was conducted to identify novel interacting proteins of IRE1α. Ribosome sequencing and polysome profiling were performed to determine the molecular basis for the function of IRE1α in translational control. RESULTS: We show that IRE1α is required for cell growth in neonatal rat ventricular myocytes under prohypertrophy treatment and in HEK293 cells in response to serum stimulation. At the molecular level, IRE1α directly interacts with eIF4G and eIF3, 2 critical components of the translation initiation complex. We demonstrate that IRE1α facilitates the formation of the translation initiation complex around the endoplasmic reticulum and preferentially initiates the translation of transcripts with 5' terminal oligopyrimidine motifs. We then reveal that IRE1α plays an important role in determining the selectivity and translation of these transcripts. We next show that IRE1α stimulates the translation of epidermal growth factor receptor through an unannotated terminal oligopyrimidine motif in its 5' untranslated region. We further demonstrate a physiological role of IRE1α-governed protein translation by showing that IRE1α is essential for cardiomyocyte growth and cardiac functional maintenance under hemodynamic stress in vivo. CONCLUSIONS: These studies suggest a noncanonical, essential role of IRE1α in orchestrating protein synthesis, which may have important implications in cardiac hypertrophy in response to pressure overload and general cell growth under other physiological and pathological conditions.
RESUMO
Heart failure with preserved ejection fraction (HFpEF) is a common syndrome with high morbidity and mortality for which there are no evidence-based therapies. Here we report that concomitant metabolic and hypertensive stress in mice-elicited by a combination of high-fat diet and inhibition of constitutive nitric oxide synthase using Nω-nitro-L-arginine methyl ester (L-NAME)-recapitulates the numerous systemic and cardiovascular features of HFpEF in humans. Expression of one of the unfolded protein response effectors, the spliced form of X-box-binding protein 1 (XBP1s), was reduced in the myocardium of our rodent model and in humans with HFpEF. Mechanistically, the decrease in XBP1s resulted from increased activity of inducible nitric oxide synthase (iNOS) and S-nitrosylation of the endonuclease inositol-requiring protein 1α (IRE1α), culminating in defective XBP1 splicing. Pharmacological or genetic suppression of iNOS, or cardiomyocyte-restricted overexpression of XBP1s, each ameliorated the HFpEF phenotype. We report that iNOS-driven dysregulation of the IRE1α-XBP1 pathway is a crucial mechanism of cardiomyocyte dysfunction in HFpEF.
Assuntos
Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/fisiopatologia , Estresse Nitrosativo , Volume Sistólico , Animais , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Endorribonucleases/metabolismo , Insuficiência Cardíaca/prevenção & controle , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Miócitos Cardíacos/enzimologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/deficiência , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Fenótipo , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Proteína 1 de Ligação a X-Box/genética , Proteína 1 de Ligação a X-Box/metabolismoRESUMO
Heart failure with preserved ejection fraction (HFpEF) is now the most common form of heart failure and a significant public health concern for which limited effective therapies exist. Inflammation triggered by comorbidity burden is a critical element of HFpEF pathophysiology. Here, we discuss evidence for comorbidity-driven systemic and myocardial inflammation and the mechanistic role of inflammation in pathological myocardial remodeling in HFpEF.
Assuntos
Insuficiência Cardíaca , Humanos , Insuficiência Cardíaca/epidemiologia , Insuficiência Cardíaca/patologia , Volume Sistólico/fisiologia , Miocárdio , Comorbidade , Inflamação/patologiaRESUMO
Heart failure with preserved ejection fraction (HFpEF) represents one of the greatest challenges facing cardiovascular medicine today. Despite being the most common form of heart failure worldwide, there has been limited success in developing therapeutics for this syndrome. This is largely due to our incomplete understanding of the biology driving its systemic pathophysiology and the heterogeneity of clinical phenotypes, which are increasingly being recognized as distinct HFpEF phenogroups. Development of efficacious therapeutics fundamentally relies on robust preclinical models that not only faithfully recapitulate key features of the clinical syndrome but also enable rigorous investigation of putative mechanisms of disease in the context of clinically relevant phenotypes. In this review, we propose a preclinical research strategy that is conceptually grounded in model diversification and aims to better align with our evolving understanding of the heterogeneity of clinical HFpEF. Although heterogeneity is often viewed as a major obstacle in preclinical HFpEF research, we challenge this notion and argue that embracing it may be the key to demystifying its pathobiology. Here, we first provide an overarching guideline for developing HFpEF models through a stepwise approach of comprehensive cardiac and extra-cardiac phenotyping. We then present an overview of currently available models, focused on the 3 leading phenogroups, which are primarily based on aging, cardiometabolic stress, and chronic hypertension. We discuss how well these models reflect their clinically relevant phenogroup and highlight some of the more recent mechanistic insights they are providing into the complex pathophysiology underlying HFpEF.
Assuntos
Fármacos Cardiovasculares , Insuficiência Cardíaca , Insuficiência Cardíaca/genética , Insuficiência Cardíaca/terapia , Humanos , Volume Sistólico/fisiologiaRESUMO
BACKGROUND: Cellular redox control is maintained by generation of reactive oxygen/nitrogen species balanced by activation of antioxidative pathways. Disruption of redox balance leads to oxidative stress, a central causative event in numerous diseases including heart failure. Redox control in the heart exposed to hemodynamic stress, however, remains to be fully elucidated. METHODS: Pressure overload was triggered by transverse aortic constriction in mice. Transcriptomic and metabolomic regulations were evaluated by RNA-sequencing and metabolomics, respectively. Stable isotope tracer labeling experiments were conducted to determine metabolic flux in vitro. Neonatal rat ventricular myocytes and H9c2 cells were used to examine molecular mechanisms. RESULTS: We show that production of cardiomyocyte NADPH, a key factor in redox regulation, is decreased in pressure overload-induced heart failure. As a consequence, the level of reduced glutathione is downregulated, a change associated with fibrosis and cardiomyopathy. We report that the pentose phosphate pathway and mitochondrial serine/glycine/folate metabolic signaling, 2 NADPH-generating pathways in the cytosol and mitochondria, respectively, are induced by transverse aortic constriction. We identify ATF4 (activating transcription factor 4) as an upstream transcription factor controlling the expression of multiple enzymes in these 2 pathways. Consistently, joint pathway analysis of transcriptomic and metabolomic data reveal that ATF4 preferably controls oxidative stress and redox-related pathways. Overexpression of ATF4 in neonatal rat ventricular myocytes increases NADPH-producing enzymes' whereas silencing of ATF4 decreases their expression. Further, stable isotope tracer experiments reveal that ATF4 overexpression augments metabolic flux within these 2 pathways. In vivo, cardiomyocyte-specific deletion of ATF4 exacerbates cardiomyopathy in the setting of transverse aortic constriction and accelerates heart failure development, attributable, at least in part, to an inability to increase the expression of NADPH-generating enzymes. CONCLUSIONS: Our findings reveal that ATF4 plays a critical role in the heart under conditions of hemodynamic stress by governing both cytosolic and mitochondrial production of NADPH.
Assuntos
Insuficiência Cardíaca , Estresse Oxidativo , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Animais , Insuficiência Cardíaca/metabolismo , Camundongos , Miócitos Cardíacos/metabolismo , NADP/metabolismo , Estresse Oxidativo/fisiologia , Ratos , Espécies Reativas de Oxigênio/metabolismoRESUMO
Large-scale clinical trials are essential in cardiology and require rapid, accurate publication, and dissemination. Whereas conference presentations, press releases, and social media disseminate information quickly and often receive considerable coverage by mainstream and healthcare media, they lack detail, may emphasize selected data, and can be open to misinterpretation. Preprint servers speed access to research manuscripts while awaiting acceptance for publication by a journal, but these articles are not formally peer-reviewed and sometimes overstate the findings. Publication of trial results in a major journal is very demanding but the use of existing checklists can help accelerate the process. In case of rejection, procedures such as easing formatting requirements and possibly carrying over peer-review to other journals could speed resubmission. Secondary publications can help maximize benefits from clinical trials; publications of secondary endpoints and subgroup analyses further define treatment effects and the patient populations most likely to benefit. These rely on data access, and although data sharing is becoming more common, many challenges remain. Beyond publication in medical journals, there is a need for wider knowledge dissemination to maximize impact on clinical practice. This might be facilitated through plain language summary publications. Social media, websites, mainstream news outlets, and other publications, although not peer-reviewed, are important sources of medical information for both the public and for clinicians. This underscores the importance of ensuring that the information is understandable, accessible, balanced, and trustworthy. This report is based on discussions held on December 2021, at the 18th Global Cardiovascular Clinical Trialists meeting, involving a panel of editors of some of the top medical journals, as well as members of the lay press, industry, and clinical trialists.
RESUMO
[Figure: see text].
Assuntos
Insuficiência Cardíaca Diastólica/terapia , Mitocôndrias Cardíacas/metabolismo , Miopatias Mitocondriais/terapia , NAD/biossíntese , Niacinamida/análogos & derivados , Compostos de Piridínio/administração & dosagem , Acetilação , Acil-CoA Desidrogenase/metabolismo , Animais , Modelos Animais de Doenças , Regulação para Baixo , Ácidos Graxos/metabolismo , Humanos , Cetona Oxirredutases/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Miopatias Mitocondriais/metabolismo , NAD/análise , NAD/deficiência , NAD/genética , Niacinamida/administração & dosagem , Oxirredução , Consumo de Oxigênio , Sirtuína 3/metabolismoRESUMO
[Figure: see text].
Assuntos
Células Endoteliais/metabolismo , Endotélio Vascular/citologia , Morfogênese , Mioblastos/metabolismo , Proteína Proto-Oncogênica c-fli-1/metabolismo , Animais , Diferenciação Celular , Células Cultivadas , Células Endoteliais/citologia , Endotélio Vascular/embriologia , Endotélio Vascular/metabolismo , Mesoderma/citologia , Mesoderma/embriologia , Mesoderma/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Proteína MyoD/genética , Proteína MyoD/metabolismo , Mioblastos/citologia , Fator Regulador Miogênico 5/genética , Fator Regulador Miogênico 5/metabolismo , Proteína Proto-Oncogênica c-fli-1/genéticaRESUMO
[Figure: see text].
Assuntos
Infarto do Miocárdio/metabolismo , Miofibroblastos/metabolismo , Pirofosfatases/metabolismo , Animais , Células Cultivadas , Fibrose , Células HEK293 , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Infarto do Miocárdio/patologia , Miocárdio/metabolismo , Miocárdio/patologia , Miofibroblastos/patologia , Pirofosfatases/genéticaRESUMO
[Figure: see text].
Assuntos
Autofagia , Proteína Beclina-1/farmacologia , Traumatismo por Reperfusão Miocárdica/metabolismo , Miócitos Cardíacos/metabolismo , Animais , Proteína 7 Relacionada à Autofagia/genética , Proteína 7 Relacionada à Autofagia/metabolismo , Proteína Beclina-1/uso terapêutico , Células Cultivadas , Camundongos , Camundongos Endogâmicos C57BL , Contração Miocárdica , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/fisiologia , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Proteínas Recombinantes/farmacologia , Proteínas Recombinantes/uso terapêuticoRESUMO
The adult mammalian heart is incapable of regeneration following cardiomyocyte loss, which underpins the lasting and severe effects of cardiomyopathy. Recently, it has become clear that the mammalian heart is not a post-mitotic organ. For example, the neonatal heart is capable of regenerating lost myocardium, and the adult heart is capable of modest self-renewal. In both of these scenarios, cardiomyocyte renewal occurs via the proliferation of pre-existing cardiomyocytes, and is regulated by aerobic-respiration-mediated oxidative DNA damage. Therefore, we reasoned that inhibiting aerobic respiration by inducing systemic hypoxaemia would alleviate oxidative DNA damage, thereby inducing cardiomyocyte proliferation in adult mammals. Here we report that, in mice, gradual exposure to severe systemic hypoxaemia, in which inspired oxygen is gradually decreased by 1% and maintained at 7% for 2 weeks, results in inhibition of oxidative metabolism, decreased reactive oxygen species production and oxidative DNA damage, and reactivation of cardiomyocyte mitosis. Notably, we find that exposure to hypoxaemia 1 week after induction of myocardial infarction induces a robust regenerative response with decreased myocardial fibrosis and improvement of left ventricular systolic function. Genetic fate-mapping analysis confirms that the newly formed myocardium is derived from pre-existing cardiomyocytes. These results demonstrate that the endogenous regenerative properties of the adult mammalian heart can be reactivated by exposure to gradual systemic hypoxaemia, and highlight the potential therapeutic role of hypoxia in regenerative medicine.
Assuntos
Coração/crescimento & desenvolvimento , Hipóxia/metabolismo , Miocárdio/citologia , Miocárdio/metabolismo , Regeneração , Medicina Regenerativa/métodos , Animais , Cardiomiopatias/metabolismo , Cardiomiopatias/patologia , Proliferação de Células , Respiração Celular , Dano ao DNA , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Mitose , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Miocárdio/patologia , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Função Ventricular EsquerdaRESUMO
BACKGROUND: Cardiac hypertrophy is an independent risk factor for heart failure, a leading cause of morbidity and mortality globally. The calcineurin/NFAT (nuclear factor of activated T cells) pathway and the MAPK (mitogen-activated protein kinase)/Erk (extracellular signal-regulated kinase) pathway contribute to the pathogenesis of cardiac hypertrophy as an interdependent network of signaling cascades. How these pathways interact remains unclear and few direct targets responsible for the prohypertrophic role of NFAT have been described. METHODS: By engineering cardiomyocyte-specific ETS2 (a member of the E26 transformation-specific sequence [ETS] domain family) knockout mice, we investigated the role of ETS2 in cardiac hypertrophy. Primary cardiomyocytes were used to evaluate ETS2 function in cell growth. RESULTS: ETS2 is phosphorylated and activated by Erk1/2 on hypertrophic stimulation in both mouse (n=3) and human heart samples (n=8 to 19). Conditional deletion of ETS2 in mouse cardiomyocytes protects against pressure overload-induced cardiac hypertrophy (n=6 to 11). Silencing of ETS2 in the hearts of calcineurin transgenic mice significantly attenuates hypertrophic growth and contractile dysfunction (n=8). As a transcription factor, ETS2 is capable of binding to the promoters of hypertrophic marker genes, such as ANP, BNP, and Rcan1.4 (n=4). We report that ETS2 forms a complex with NFAT to stimulate transcriptional activity through increased NFAT binding to the promoters of at least 2 hypertrophy-stimulated genes: Rcan1.4 and microRNA-223 (=n4 to 6). Suppression of microRNA-223 in cardiomyocytes inhibits calcineurin-mediated cardiac hypertrophy (n=6), revealing microRNA-223 as a novel prohypertrophic target of the calcineurin/NFAT and Erk1/2-ETS2 pathways. CONCLUSIONS: Our findings point to a critical role for ETS2 in calcineurin/NFAT pathway-driven cardiac hypertrophy and unveil a previously unknown molecular connection between the Erk1/2 activation of ETS2 and expression of NFAT/ETS2 target genes.
Assuntos
Calcineurina/metabolismo , Cardiomegalia/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , Fatores de Transcrição NFATC/metabolismo , Proteína Proto-Oncogênica c-ets-2/metabolismo , Animais , Calcineurina/genética , Cardiomegalia/genética , Cardiomegalia/patologia , Células Cultivadas , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Fatores de Transcrição NFATC/genética , Ligação Proteica/fisiologia , Proteína Proto-Oncogênica c-ets-2/genética , Ratos , Ratos Sprague-DawleyRESUMO
While we continue to wrestle with the immense challenge of implementing equitable access to established evidence-based treatments, substantial gaps remain in our pharmacotherapy armament for common forms of cardiovascular disease including coronary and peripheral arterial disease, heart failure, hypertension, and arrhythmia. We need to continue to invest in the development of new approaches for the discovery, rigorous assessment, and implementation of new therapies. Currently, the time and cost to progress from lead compound/product identification to the clinic, and the success rate in getting there reduces the incentive for industry to invest, despite the enormous burden of disease and potential size of market. There are tremendous opportunities with improved phenotyping of patients currently batched together in syndromic "buckets." Use of advanced imaging and molecular markers may allow stratification of patients in a manner more aligned to biological mechanisms that can, in turn, be targeted by specific approaches developed using high-throughput molecular technologies. Unbiased "omic" approaches enhance the possibility of discovering completely new mechanisms in such groups. Furthermore, advances in drug discovery platforms, and models to study efficacy and toxicity more relevant to the human disease, are valuable. Re-imagining the relationships among discovery, translation, evaluation, and implementation will help reverse the trend away from investment in the cardiovascular space, establishing innovative platforms and approaches across the full spectrum of therapeutic development.
Assuntos
Doenças Cardiovasculares/tratamento farmacológico , Descoberta de Drogas/métodos , HumanosRESUMO
Acetyl-coenzyme A (AcCoA) is a major integrator of the nutritional status at the crossroads of fat, sugar, and protein catabolism. Here we show that nutrient starvation causes rapid depletion of AcCoA. AcCoA depletion entailed the commensurate reduction in the overall acetylation of cytoplasmic proteins, as well as the induction of autophagy, a homeostatic process of self-digestion. Multiple distinct manipulations designed to increase or reduce cytosolic AcCoA led to the suppression or induction of autophagy, respectively, both in cultured human cells and in mice. Moreover, maintenance of high AcCoA levels inhibited maladaptive autophagy in a model of cardiac pressure overload. Depletion of AcCoA reduced the activity of the acetyltransferase EP300, and EP300 was required for the suppression of autophagy by high AcCoA levels. Altogether, our results indicate that cytosolic AcCoA functions as a central metabolic regulator of autophagy, thus delineating AcCoA-centered pharmacological strategies that allow for the therapeutic manipulation of autophagy.
Assuntos
Acetilcoenzima A/química , Autofagia , Citosol/enzimologia , Regulação Enzimológica da Expressão Gênica , Trifosfato de Adenosina/química , Animais , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Citosol/metabolismo , Proteína p300 Associada a E1A/química , Proteínas de Fluorescência Verde/metabolismo , Células HCT116 , Células HeLa , Humanos , Ácidos Cetoglutáricos/química , Camundongos , Camundongos Endogâmicos C57BL , Microscopia de Fluorescência , Mitocôndrias/metabolismo , RNA Interferente Pequeno/metabolismoRESUMO
Hypercholesterolaemia is an important risk factor for cardiovascular disease. Both total and LDL cholesterol levels are three-fold higher at the end of the first year of life and about four-fold higher in adulthood compared with the neonatal period. In the USA, only 25% of infants are exclusively breastfed and simple carbohydrate-rich formulas are preferentially consumed. Spikes in fasting glucose and insulin have been reported in formula-fed infants and are associated with higher levels of proprotein convertase subtilisin/kexin type 9, suggesting a potential link between high simple sugar intake and consequent increase in LDL cholesterol in early childhood.
Assuntos
Doenças Cardiovasculares , Hipercolesterolemia , Adulto , Pré-Escolar , LDL-Colesterol , Humanos , Lactente , Recém-Nascido , Pró-Proteína Convertase 9 , Fatores de Risco , AçúcaresRESUMO
Whilst we continue to wrestle with the immense challenge of implementing equitable access to established evidence-based treatments, substantial gaps remain in our pharmacotherapy armament for common forms of cardiovascular disease including coronary and peripheral arterial disease, heart failure, hypertension, and arrhythmia. We need to continue to invest in the development of new approaches for the discovery, rigorous assessment, and implementation of new therapies. Currently, the time and cost to progress from lead compound/product identification to the clinic, and the success rate in getting there reduces the incentive for industry to invest, despite the enormous burden of disease and potential size of market. There are tremendous opportunities with improved phenotyping of patients currently batched together in syndromic 'buckets'. Use of advanced imaging and molecular markers may allow stratification of patients in a manner more aligned to biological mechanisms that can, in turn, be targeted by specific approaches developed using high-throughput molecular technologies. Unbiased 'omic' approaches enhance the possibility of discovering completely new mechanisms in such groups. Furthermore, advances in drug discovery platforms, and models to study efficacy and toxicity more relevant to the human disease, are valuable. Re-imagining the relationships among discovery, translation, evaluation, and implementation will help reverse the trend away from investment in the cardiovascular space, establishing innovative platforms and approaches across the full spectrum of therapeutic development.