RESUMO
Single-nucleotide variations in C13orf31 (LACC1) that encode p.C284R and p.I254V in a protein of unknown function (called 'FAMIN' here) are associated with increased risk for systemic juvenile idiopathic arthritis, leprosy and Crohn's disease. Here we set out to identify the biological mechanism affected by these coding variations. FAMIN formed a complex with fatty acid synthase (FASN) on peroxisomes and promoted flux through de novo lipogenesis to concomitantly drive high levels of fatty-acid oxidation (FAO) and glycolysis and, consequently, ATP regeneration. FAMIN-dependent FAO controlled inflammasome activation, mitochondrial and NADPH-oxidase-dependent production of reactive oxygen species (ROS), and the bactericidal activity of macrophages. As p.I254V and p.C284R resulted in diminished function and loss of function, respectively, FAMIN determined resilience to endotoxin shock. Thus, we have identified a central regulator of the metabolic function and bioenergetic state of macrophages that is under evolutionary selection and determines the risk of inflammatory and infectious disease.
Assuntos
Artrite Juvenil/genética , Doença de Crohn/genética , Infecções/genética , Hanseníase/genética , Macrófagos/imunologia , Proteínas/genética , Choque Séptico/genética , Trifosfato de Adenosina/metabolismo , Animais , Bacteriólise , Células Cultivadas , Metabolismo Energético , Ácido Graxo Sintase Tipo I/metabolismo , Predisposição Genética para Doença , Humanos , Inflamassomos/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular , Metabolismo dos Lipídeos/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , NADPH Oxidases/metabolismo , Oxirredução , Polimorfismo de Nucleotídeo Único , RiscoRESUMO
Several genetic discoveries robustly implicate five single-nucleotide variants in the progression of non-alcoholic fatty liver disease to non-alcoholic steatohepatitis and fibrosis (NASH-fibrosis), including a recently identified variant in MTARC1. To better understand these variants as potential therapeutic targets, we aimed to characterize their impact on metabolism using comprehensive metabolomics data from two population-based studies. A total of 9135 participants from the Fenland study and 9902 participants from the EPIC-Norfolk cohort were included in the study. We identified individuals with risk alleles associated with NASH-fibrosis: rs738409C>G in PNPLA3, rs58542926C>T in TM6SF2, rs641738C>T near MBOAT7, rs72613567TA>T in HSD17B13 and rs2642438A>G in MTARC1. Circulating levels of 1449 metabolites were measured using targeted and untargeted metabolomics. Associations between NASH-fibrosis variants and metabolites were assessed using linear regression. The specificity of variant-metabolite associations were compared to metabolite associations with ultrasound-defined steatosis, gene variants linked to liver fat (in GCKR, PPP1R3B and LYPLAL1) and gene variants linked to cirrhosis (in HFE and SERPINA1). Each NASH-fibrosis variant demonstrated a specific metabolite profile with little overlap (8/97 metabolites) comprising diverse aspects of lipid metabolism. Risk alleles in PNPLA3 and HSD17B13 were both associated with higher 3-methylglutarylcarnitine and three variants were associated with lower lysophosphatidylcholine C14:0. The risk allele in MTARC1 was associated with higher levels of sphingomyelins. There was no overlap with metabolites that associated with HFE or SERPINA1 variants. Our results suggest a link between the NASH-protective variant in MTARC1 to the metabolism of sphingomyelins and identify distinct molecular patterns associated with each of the NASH-fibrosis variants under investigation.
Assuntos
Predisposição Genética para Doença , Cirrose Hepática/patologia , Metaboloma , Hepatopatia Gordurosa não Alcoólica/patologia , Polimorfismo de Nucleotídeo Único , Adulto , Idoso , Feminino , Estudos de Associação Genética , Humanos , Cirrose Hepática/complicações , Cirrose Hepática/genética , Cirrose Hepática/metabolismo , Masculino , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/complicações , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/metabolismo , Prognóstico , Estudos ProspectivosRESUMO
BACKGROUND: Accumulating evidence suggests that individual circulating saturated fatty acids (SFAs) are heterogeneous in their associations with cardio-metabolic diseases, but evidence about associations of SFAs with metabolic markers of different pathogenic pathways is limited. We aimed to examine the associations between plasma phospholipid SFAs and the metabolic markers of lipid, hepatic, glycaemic and inflammation pathways. METHODS: We measured nine individual plasma phospholipid SFAs and derived three SFA groups (odd-chain: C15:0 + C17:0, even-chain: C14:0 + C16:0 + C18:0, and very-long-chain: C20:0 + C22:0 + C23:0 + C24:0) in individuals from the subcohort of the European Prospective Investigation into Cancer and Nutrition (EPIC)-InterAct case-cohort study across eight European countries. Using linear regression in 15,919 subcohort members, adjusted for potential confounders and corrected for multiple testing, we examined cross-sectional associations of SFAs with 13 metabolic markers. Multiplicative interactions of the three SFA groups with pre-specified factors, including body mass index (BMI) and alcohol consumption, were tested. RESULTS: Higher levels of odd-chain SFA group were associated with lower levels of major lipids (total cholesterol (TC), triglycerides, apolipoprotein A-1 (ApoA1), apolipoprotein B (ApoB)) and hepatic markers (alanine transaminase (ALT), aspartate transaminase (AST), gamma-glutamyl transferase (GGT)). Higher even-chain SFA group levels were associated with higher levels of low-density lipoprotein cholesterol (LDL-C), TC/high-density lipoprotein cholesterol (HDL-C) ratio, triglycerides, ApoB, ApoB/A1 ratio, ALT, AST, GGT and CRP, and lower levels of HDL-C and ApoA1. Very-long-chain SFA group levels showed inverse associations with triglycerides, ApoA1 and GGT, and positive associations with TC, LDL-C, TC/HDL-C, ApoB and ApoB/A1. Associations were generally stronger at higher levels of BMI or alcohol consumption. CONCLUSIONS: Subtypes of SFAs are associated in a differential way with metabolic markers of lipid metabolism, liver function and chronic inflammation, suggesting that odd-chain SFAs are associated with lower metabolic risk and even-chain SFAs with adverse metabolic risk, whereas mixed findings were obtained for very-long-chain SFAs. The clinical and biochemical implications of these findings may vary by adiposity and alcohol intake.
Assuntos
Biomarcadores/sangue , Glicemia/metabolismo , Ácidos Graxos/sangue , Inflamação/sangue , Lipídeos/sangue , Adulto , Idoso , Índice de Massa Corporal , HDL-Colesterol , LDL-Colesterol/sangue , Estudos Transversais , Gorduras na Dieta/metabolismo , Europa (Continente) , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Triglicerídeos/sangue , Adulto JovemRESUMO
Cardiomyocytes are vulnerable to hypoxia in the adult, but adapted to hypoxia in utero. Current understanding of endogenous cardiac oxygen sensing pathways is limited. Myocardial oxygen consumption is determined by regulation of energy metabolism, which shifts from glycolysis to lipid oxidation soon after birth, and is reversed in failing adult hearts, accompanying re-expression of several "fetal" genes whose role in disease phenotypes remains unknown. Here we show that hypoxia-controlled expression of the transcription factor Hand1 determines oxygen consumption by inhibition of lipid metabolism in the fetal and adult cardiomyocyte, leading to downregulation of mitochondrial energy generation. Hand1 is under direct transcriptional control by HIF1α. Transgenic mice prolonging cardiac Hand1 expression die immediately following birth, failing to activate the neonatal lipid metabolising gene expression programme. Deletion of Hand1 in embryonic cardiomyocytes results in premature expression of these genes. Using metabolic flux analysis, we show that Hand1 expression controls cardiomyocyte oxygen consumption by direct transcriptional repression of lipid metabolising genes. This leads, in turn, to increased production of lactate from glucose, decreased lipid oxidation, reduced inner mitochondrial membrane potential, and mitochondrial ATP generation. We found that this pathway is active in adult cardiomyocytes. Up-regulation of Hand1 is protective in a mouse model of myocardial ischaemia. We propose that Hand1 is part of a novel regulatory pathway linking cardiac oxygen levels with oxygen consumption. Understanding hypoxia adaptation in the fetal heart may allow development of strategies to protect cardiomyocytes vulnerable to ischaemia, for example during cardiac ischaemia or surgery.
Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Metabolismo Energético/genética , Metabolismo dos Lipídeos/genética , Miocárdio/metabolismo , Consumo de Oxigênio/genética , Trifosfato de Adenosina/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Hipóxia Celular/genética , Linhagem Celular , Regulação da Expressão Gênica no Desenvolvimento , Coração/embriologia , Coração/fisiologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Potencial da Membrana Mitocondrial/genética , Camundongos , Camundongos Transgênicos , Mitocôndrias/metabolismo , Isquemia Miocárdica/genética , Isquemia Miocárdica/metabolismo , Miócitos Cardíacos/metabolismo , Oxigênio/metabolismo , Ativação TranscricionalRESUMO
Compared to replicative lifespan, epigenetic regulation of chronological lifespan (CLS) is less well understood in yeast. Here, by screening all the viable mutants of histone acetyltransferase (HAT) and histone deacetylase (HDAC), we demonstrate that Gcn5, functioning in the HAT module of the SAGA/SLIK complex, exhibits an epistatic relationship with the HDAC Hda1 to control the expression of starvation-induced stress response and respiratory cell growth. Surprisingly, the gcn5Δ mutants lose their colony-forming potential early in the stationary phase but display a longer maximum CLS than their WT counterparts, suggesting the contradictory roles of Gcn5 in lifespan regulation. Integrative analyses of the transcriptome, metabolome and ChIP assays reveal that Gcn5 is necessary for the activation of two regulons upon glucose starvation: the Msn2/4-/Gis1-dependent stress response and the Cat8-/Adr1-mediated metabolic reprogramming, to enable pro-longevity characteristics, including redox homeostasis, stress resistance and maximal storage of carbohydrates. The activation of Cat8-/Adr1-dependent regulon also promotes the pyruvate dehydrogenase (PDH) bypass, leading to acetyl-CoA synthesis, global and targeted H3K9 acetylation. Global H3K9 acetylation levels mediated by Gcn5 and Hda1 during the transition into stationary phase are positively correlated with senescent cell populations accumulated in the aged cell cultures. These data suggest that Gcn5 lies in the centre of a feed-forward loop between histone acetylation and starvation-induced gene expression, enabling stress resistance and homeostasis but also promoting chronological ageing concomitantly.
Assuntos
Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Epigênese Genética , Histona Acetiltransferases/genética , Histona Acetiltransferases/metabolismo , AcetilaçãoRESUMO
Current understanding of tumor immunosuppressive mechanisms forms the basis for modern day immunotherapies. Immunoregulatory role of platelets in cancer remains largely elusive. Platelets from non-small cell lung cancer (NSCLC) patients revealed a distinct activation phenotype. TREM-like transcript 1 (TLT-1), a platelet protein, was increased along with enhanced extracellular release from NSCLC platelets. The increased platelet TLT-1 was also evident in humanized mice with patient-derived tumors. In immunocompetent mice with syngeneic tumors, TLT-1 binding to T cells, in vivo, led to suppression of CD8 T cells, promoting tumor growth. We identified direct interaction between TLT-1 and CD3ε on T cells, implicating the NF-κB pathway in CD8 T cell suppression. Anti-TLT-1 antibody rescued patients' T cells from platelet-induced suppression ex vivo and reduced tumors in mice in vivo. Clinically, higher TLT-1 correlated with reduced survival of NSCLC patients. Our findings thus identify TLT-1 as a platelet-derived immunosuppressor that suppresses CD8 T cells and demonstrate its therapeutic and prognostic significance in cancer.
Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Camundongos , Animais , Receptores Imunológicos/metabolismo , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Neoplasias Pulmonares/metabolismo , Plaquetas/metabolismo , Linfócitos T CD8-PositivosRESUMO
Death receptor 3 (DR3), a member of the TNF receptor (TNFR) superfamily, is induced in human renal tubular epithelial cells (TEC) in response to injury. This study examined the expression and actions of TL1A, the principal ligand for DR3. In histologically normal tissue from biopsy or nephrectomy specimens of renal allografts, TL1A mRNA and protein were expressed in vascular endothelial cells but not in TEC. In specimens of acute or antibody-mediated allograft rejection, vascular endothelial cells and infiltrating leukocytes expressed increased TL1A mRNA and protein, but TEC expressed TL1A protein without mRNA, consistent with uptake of exogenous ligand. Addition of TL1A to organ cultures of human or mouse kidney caused activation of NF-kappaB, expression of TNFR2, activation of caspase-3, and apoptosis in TEC. Inhibition of NF-kappaB activation increased TL1A-mediated caspase-3 activation and apoptosis of TEC, but it did not reduce the induction of TNFR2. In organ culture of DR3-deficient mouse kidneys, addition of TL1A induced TNFR2 but did not activate NF-kappaB and did not increase apoptosis of TEC. These data suggest that TL1A may contribute to renal inflammation and injury through DR3-mediated activation of NF-kappaB and caspase-3, respectively, but that an unidentified receptor may mediate the NF-kappaB-independent induction of TNFR2 in TEC.
Assuntos
Rejeição de Enxerto/fisiopatologia , Transplante de Rim , Nefrite/fisiopatologia , Membro 15 da Superfamília de Ligantes de Fatores de Necrose Tumoral/genética , Membro 15 da Superfamília de Ligantes de Fatores de Necrose Tumoral/imunologia , Animais , Apoptose/fisiologia , Biópsia , Caspase 3/metabolismo , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/patologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , NF-kappa B/metabolismo , Nefrite/imunologia , Nefrite/patologia , Técnicas de Cultura de Órgãos , RNA Mensageiro/metabolismo , Membro 25 de Receptores de Fatores de Necrose Tumoral/genética , Membro 25 de Receptores de Fatores de Necrose Tumoral/metabolismo , Receptores Tipo II do Fator de Necrose Tumoral/genética , Receptores Tipo II do Fator de Necrose Tumoral/metabolismo , Membro 15 da Superfamília de Ligantes de Fatores de Necrose Tumoral/metabolismoRESUMO
BACKGROUND: Smoking and COPD are risk factors for cardiovascular disease, and the pathogenesis may involve endothelial dysfunction. We tested the hypothesis that endothelium-derived epoxyeicosatrienoic acid (EET)-mediated endothelial function is impaired in patients with COPD and that a novel soluble epoxide hydrolase inhibitor, GSK2256294, attenuates EET-mediated endothelial dysfunction in human resistance vessels both in vitro and in vivo. METHODS: Endogenous and stimulated endothelial release of EETs was assessed in 12 patients with COPD, 11 overweight smokers, and two matched control groups, using forearm plethysmography with intraarterial infusions of fluconazole, bradykinin, and the combination. The effects of GSK2256294 on EET-mediated vasodilation in human resistance arteries were assessed in vitro and in vivo in a phase I clinical trial in healthy overweight smokers. RESULTS: Compared with control groups, there was reduced vasodilation with bradykinin (P = .005), a blunted effect of fluconazole on bradykinin-induced vasodilation (P = .03), and a trend toward reduced basal EET/dihydroxyepoxyeicosatrienoic acid ratio in patients with COPD (P = .08). A similar pattern was observed in overweight smokers. In vitro, 10 µM GSK2256294 increased 11,12-EET-mediated vasodilation compared with vehicle (90% ± 4.2% vs 72.6% ± 6.2% maximal dilatation) and shifted the bradykinin half-maximal effective concentration (EC50) (-8.33 ± 0.172 logM vs -8.10 ± 0.118 logM; P = .001 for EC50). In vivo, 18 mg GSK2256294 improved the maximum bradykinin response from 338% ± 46% before a dose to 566% ± 110% after a single dose (P = .02) and to 503% ± 123% after a chronic dose (P = .003). CONCLUSIONS: GSK2256294 attenuates smoking-related EET-mediated endothelial dysfunction, suggesting potential therapeutic benefits in patients with COPD. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01762774; URL: www.clinicaltrials.gov.
Assuntos
Vasos Sanguíneos/efeitos dos fármacos , Cicloexilaminas/farmacologia , Endotélio Vascular/efeitos dos fármacos , Epóxido Hidrolases/antagonistas & inibidores , Sobrepeso/fisiopatologia , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Fumar/fisiopatologia , Triazinas/farmacologia , Vasodilatação/efeitos dos fármacos , Ácido 8,11,14-Eicosatrienoico/análogos & derivados , Ácido 8,11,14-Eicosatrienoico/metabolismo , Adulto , Idoso , Vasos Sanguíneos/fisiopatologia , Bradicinina/farmacologia , Estudos de Casos e Controles , Endotélio Vascular/metabolismo , Endotélio Vascular/fisiopatologia , Fluconazol/farmacologia , Antebraço/irrigação sanguínea , Humanos , Técnicas In Vitro , Masculino , Pessoa de Meia-Idade , Sobrepeso/metabolismo , Pletismografia , Doença Pulmonar Obstrutiva Crônica/metabolismo , Fumar/metabolismo , Vasodilatadores/farmacologiaRESUMO
Preclinical data have shown that rilmenidine can regulate autophagy in models of Huntington's disease (HD), providing a potential route to alter the disease course in patients. Consequently, a 2-year open-label study examining the tolerability and feasibility of rilmenidine in mild-moderate HD was undertaken. 18 non-demented patients with mild to moderate HD took daily doses of 1 mg Rilmenidine for 6 months and 2 mg for a further 18 months followed by a 3-month washout period. The primary outcome was the number of withdrawals and serious adverse events. Secondary outcomes included safety parameters and changes in disease-specific variables, such as motor, cognitive and functional performance, structural MRI and serum metabolomic analysis. 12 patients completed the study; reasons for withdrawal included problems tolerating study procedures (MRI, and venepuncture), depression requiring hospital admission and logistical reasons. Three serious adverse events were recorded, including hospitalisation for depression, but none were thought to be drug-related. Changes in secondary outcomes were analysed as the annual rate of change in the study group. The overall change was comparable to changes seen in recent large observational studies in HD patients, though direct statistical comparisons to these studies were not made. Chronic oral administration of rilmenidine is feasible and well-tolerated and future, larger, placebo-controlled, studies in HD are warranted. TRIAL REGISTRATION: EudraCT number 2009-018119-14.
Assuntos
Agonistas alfa-Adrenérgicos/uso terapêutico , Doença de Huntington/tratamento farmacológico , Oxazóis/uso terapêutico , Adolescente , Adulto , Idoso , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos dos fármacos , Feminino , Humanos , Doença de Huntington/sangue , Doença de Huntington/diagnóstico por imagem , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Metabolômica , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estudos Retrospectivos , Rilmenidina , Fatores de Tempo , Resultado do Tratamento , Adulto JovemRESUMO
OBJECTIVE: To review the metabolomic studies carried out so far to identify metabolic markers associated with surgical and dietary treatments for weight loss in subjects with obesity. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. RESULTS: Thirty-two studies successfully met the eligibility criteria. The metabolic adaptations shared by surgical and dietary interventions mirrored a state of starvation ketoacidosis (increase of circulating ketone bodies), an increase of acylcarnitines and fatty acid ß-oxidation, a decrease of specific amino acids including branched-chain amino acids (BCAA) and (lyso)glycerophospholipids previously associated with obesity, and adipose tissue expansion. The metabolic footprint of bariatric procedures was specifically characterized by an increase of bile acid circulating pools and a decrease of ceramide levels, a greater perioperative decline in BCAA, and the rise of circulating serine and glycine, mirroring glycemic control and inflammation improvement. In one study, 3-hydroxybutyrate was particularly identified as an early metabolic marker of long-term prognosis after surgery and proposed to increase current prognostic modalities and contribute to personalized treatment. CONCLUSIONS: Metabolomics helped in deciphering the metabolic response to weight loss treatments. Moving from association to causation is the next challenge to move to a further level of clinical application.