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1.
Elife ; 102021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34608863

RESUMO

The Connexin43 gap junction gene GJA1 has one coding exon, but its mRNA undergoes internal translation to generate N-terminal truncated isoforms of Connexin43 with the predominant isoform being only 20 kDa in size (GJA1-20k). Endogenous GJA1-20k protein is not membrane bound and has been found to increase in response to ischemic stress, localize to mitochondria, and mimic ischemic preconditioning protection in the heart. However, it is not known how GJA1-20k benefits mitochondria to provide this protection. Here, using human cells and mice, we identify that GJA1-20k polymerizes actin around mitochondria which induces focal constriction sites. Mitochondrial fission events occur within about 45 s of GJA1-20k recruitment of actin. Interestingly, GJA1-20k mediated fission is independent of canonical Dynamin-Related Protein 1 (DRP1). We find that GJA1-20k-induced smaller mitochondria have decreased reactive oxygen species (ROS) generation and, in hearts, provide potent protection against ischemia-reperfusion injury. The results indicate that stress responsive internally translated GJA1-20k stabilizes polymerized actin filaments to stimulate non-canonical mitochondrial fission which limits ischemic-reperfusion induced myocardial infarction.


Assuntos
Conexina 43/metabolismo , Mitocôndrias/metabolismo , Dinâmica Mitocondrial/genética , Animais , Conexina 43/genética , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Dinâmica Mitocondrial/fisiologia , Infarto do Miocárdio , Miócitos Cardíacos/metabolismo , Espécies Reativas de Oxigênio/metabolismo
2.
Ann N Y Acad Sci ; 2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34414571

RESUMO

There is an increasing appreciation for the role of metabolism in cell signaling and cell decision making. Precise metabolic control is essential in development, as evident by the disorders caused by mutations in metabolic enzymes. The metabolic profile of cells is often cell-type specific, changing as cells differentiate or during tumorigenesis. Recent evidence has shown that changes in metabolism are not merely a consequence of changes in cell state but that metabolites can serve to promote and/or inhibit these changes. Metabolites can link metabolic pathways with cell signaling pathways via several mechanisms, for example, by serving as substrates for protein post-translational modifications, by affecting enzyme activity via allosteric mechanisms, or by altering epigenetic markers. Unraveling the complex interactions governing metabolism, gene expression, and protein activity that ultimately govern a cell's fate will require new tools and interactions across disciplines. On March 24 and 25, 2021, experts in cell metabolism, developmental biology, and human disease met virtually for the Keystone eSymposium, "Metabolic Decisions in Development and Disease." The discussions explored how metabolites impact cellular and developmental decisions in a diverse range of model systems used to investigate normal development, developmental disorders, dietary effects, and cancer-mediated changes in metabolism.

3.
EMBO Rep ; 22(10): e51991, 2021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34351705

RESUMO

Peroxisomal biogenesis disorders (PBDs) are genetic disorders of peroxisome biogenesis and metabolism that are characterized by profound developmental and neurological phenotypes. The most severe class of PBDs-Zellweger spectrum disorder (ZSD)-is caused by mutations in peroxin genes that result in both non-functional peroxisomes and mitochondrial dysfunction. It is unclear, however, how defective peroxisomes contribute to mitochondrial impairment. In order to understand the molecular basis of this inter-organellar relationship, we investigated the fate of peroxisomal mRNAs and proteins in ZSD model systems. We found that peroxins were still expressed and a subset of them accumulated on the mitochondrial membrane, which resulted in gross mitochondrial abnormalities and impaired mitochondrial metabolic function. We showed that overexpression of ATAD1, a mitochondrial quality control factor, was sufficient to rescue several aspects of mitochondrial function in human ZSD fibroblasts. Together, these data suggest that aberrant peroxisomal protein localization is necessary and sufficient for the devastating mitochondrial morphological and metabolic phenotypes in ZSDs.


Assuntos
Transtornos Peroxissômicos , Síndrome de Zellweger , Humanos , Mitocôndrias/genética , Peroxinas/metabolismo , Transtornos Peroxissômicos/genética , Transtornos Peroxissômicos/metabolismo , Peroxissomos/metabolismo , Síndrome de Zellweger/genética , Síndrome de Zellweger/metabolismo
4.
Nat Commun ; 12(1): 3440, 2021 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-34103529

RESUMO

The multi-subunit translation initiation factor eIF2B is a control node for protein synthesis. eIF2B activity is canonically modulated through stress-responsive phosphorylation of its substrate eIF2. The eIF2B regulatory subcomplex is evolutionarily related to sugar-metabolizing enzymes, but the biological relevance of this relationship was unknown. To identify natural ligands that might regulate eIF2B, we conduct unbiased binding- and activity-based screens followed by structural studies. We find that sugar phosphates occupy the ancestral catalytic site in the eIF2Bα subunit, promote eIF2B holoenzyme formation and enhance enzymatic activity towards eIF2. A mutant in the eIF2Bα ligand pocket that causes Vanishing White Matter disease fails to engage and is not stimulated by sugar phosphates. These data underscore the importance of allosteric metabolite modulation for proper eIF2B function. We propose that eIF2B evolved to couple nutrient status via sugar phosphate sensing with the rate of protein synthesis, one of the most energetically costly cellular processes.


Assuntos
Fator de Iniciação 2B em Eucariotos/metabolismo , Estresse Fisiológico , Fosfatos Açúcares/metabolismo , Regulação Alostérica , Sítios de Ligação , Sequência Conservada , Microscopia Crioeletrônica , Fator de Iniciação 2B em Eucariotos/química , Fator de Iniciação 2B em Eucariotos/ultraestrutura , Evolução Molecular , Guanosina Difosfato/metabolismo , Células HEK293 , Humanos , Leucoencefalopatias/patologia , Ligantes , Metaboloma , Modelos Moleculares , Mutação/genética , Subunidades Proteicas/química , Subunidades Proteicas/metabolismo , Especificidade por Substrato , Fosfatos Açúcares/química
5.
Mol Cell ; 81(4): 642-644, 2021 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-33606971

RESUMO

Luengo et al. (2020) demonstrate that pyruvate dehydrogenase (PDH) overactivation blunts NAD+ regeneration by overcharging the mitochondrial membrane potential and driving ATP synthesis beyond demand. Under these conditions, some cells prioritize aerobic glycolysis to meet the need for oxidized cofactors in biosynthetic metabolism.


Assuntos
NAD , Complexo Piruvato Desidrogenase , Trifosfato de Adenosina , Glucose , Glicólise , NAD/metabolismo , Complexo Piruvato Desidrogenase/metabolismo , Estações do Ano
6.
Trends Biochem Sci ; 46(5): 348-350, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33618948

RESUMO

Recently, three groups, Girardi et al., Kory et al., and Luongo et al., independently identified solute carrier (SLC) 25A51 as the long-sought, major mitochondrial NAD+ transporter in mammalian cells. These studies not only deorphan an uncharacterized transporter of the SLC25A family, but also shed light on other aspects of NAD+ biology.


Assuntos
NAD , Nitrazepam , Animais , Transporte Biológico , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Nitrazepam/metabolismo
7.
Biochimie ; 183: 100-107, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33476699

RESUMO

The folate and methionine cycles, constituting one-carbon metabolism, are critical pathways for cell survival. Intersecting these two cycles, 5,10-methylenetetrahydrofolate reductase (MTHFR) directs one-carbon units from the folate to methionine cycle, to be exclusively used for methionine and S-adenosylmethionine (AdoMet) synthesis. MTHFR deficiency and upregulation result in diverse disease states, rendering it an attractive drug target. The activity of MTHFR is inhibited by the binding of AdoMet to an allosteric regulatory domain distal to the enzyme's active site, which we have previously identified to constitute a novel fold with a druggable pocket. Here, we screened 162 AdoMet mimetics using differential scanning fluorimetry, and identified 4 compounds that stabilized this regulatory domain. Three compounds were sinefungin analogues, closely related to AdoMet and S-adenosylhomocysteine (AdoHcy). The strongest thermal stabilisation was provided by (S)-SKI-72, a potent inhibitor originally developed for protein arginine methyltransferase 4 (PRMT4). Using surface plasmon resonance, we confirmed that (S)-SKI-72 binds MTHFR via its allosteric domain with nanomolar affinity. Assay of MTHFR activity in the presence of (S)-SKI-72 demonstrates inhibition of purified enzyme with sub-micromolar potency and endogenous MTHFR from HEK293 cell lysate in the low micromolar range, both of which are lower than AdoMet. Nevertheless, unlike AdoMet, (S)-SKI-72 is unable to completely abolish MTHFR activity, even at very high concentrations. Combining binding assays, kinetic characterization and compound docking, this work indicates the regulatory domain of MTHFR can be targeted by small molecules and presents (S)-SKI-72 as an excellent candidate for development of MTHFR inhibitors.


Assuntos
Inibidores Enzimáticos/química , Metilenotetra-Hidrofolato Redutase (NADPH2)/antagonistas & inibidores , Metilenotetra-Hidrofolato Redutase (NADPH2)/química , S-Adenosilmetionina/química , Regulação Alostérica , Humanos , Domínios Proteicos
8.
Cell Metab ; 33(3): 629-648.e10, 2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33333007

RESUMO

The metabolic rewiring of cardiomyocytes is a widely accepted hallmark of heart failure (HF). These metabolic changes include a decrease in mitochondrial pyruvate oxidation and an increased export of lactate. We identify the mitochondrial pyruvate carrier (MPC) and the cellular lactate exporter monocarboxylate transporter 4 (MCT4) as pivotal nodes in this metabolic axis. We observed that cardiac assist device-induced myocardial recovery in chronic HF patients was coincident with increased myocardial expression of the MPC. Moreover, the genetic ablation of the MPC in cultured cardiomyocytes and in adult murine hearts was sufficient to induce hypertrophy and HF. Conversely, MPC overexpression attenuated drug-induced hypertrophy in a cell-autonomous manner. We also introduced a novel, highly potent MCT4 inhibitor that mitigated hypertrophy in cultured cardiomyocytes and in mice. Together, we find that alteration of the pyruvate-lactate axis is a fundamental and early feature of cardiac hypertrophy and failure.

9.
J Nat Prod ; 83(11): 3381-3386, 2020 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-33151675

RESUMO

Callyspongiolide is a marine-derived macrolide that kills cells in a caspase-independent manner. NCI COMPARE analysis of human tumor cell line toxicity data for synthetic callyspongiolide indicated that its pattern of cytotoxicity correlated with that seen for concanamycin A, an inhibitor of the vacuolar-type H+-ATPase (V-ATPase). Using yeast as a model system, we report that treatment with synthetic callyspongiolide phenocopied a loss of V-ATPase activity including (1) inability to grow on a nonfermentable carbon source, (2) rescue of cell growth via supplementation with Fe2+, (3) pH-sensitive growth, and (4) a vacuolar acidification defect visualized using the fluorescent dye quinacrine. Crucially, in an in vitro assay, callyspongiolide was found to dose-dependently inhibit yeast V-ATPase (IC50 = 10 nM). Together, these data identify callyspongiolide as a new and highly potent V-ATPase inhibitor. Notably, callyspongiolide is the first V-ATPase inhibitor known to be expelled by Pdr5p.

11.
EMBO Rep ; 21(11): e50085, 2020 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-33043581

RESUMO

The cultured brown adipocytes can oxidize glucose in vitro, but it is still not fully clear whether brown adipose tissue (BAT) could completely oxidize glucose in vivo. Although positron emission tomography (PET) with 18 F-fluorodeoxyglucose (18 F-FDG) showed a high level of glucose uptake in the activated BAT, the non-metabolizable 18 F-FDG cannot fully demonstrate intracellular glucose metabolism. Through in vivo [U-13 C]glucose tracing, here we show that chronic cold exposure dramatically activates glucose oxidation in BAT and the browning/beiging subcutaneous white adipose tissue (sWAT). Specifically, chronic cold exposure enhances glucose flux into the mitochondrial TCA cycle. Metabolic flux analysis models that ß3-adrenergic receptor (ß3-AR) agonist significantly enhances the flux of mitochondrial pyruvate uptake through mitochondrial pyruvate carrier (MPC) in the differentiated primary brown adipocytes. Furthermore, in vivo MPC inhibition blocks cold-induced glucose oxidation and impairs body temperature maintenance in mice. Together, mitochondrial pyruvate uptake and oxidation serve an important energy source in the chronic cold exposure activated BAT and beige adipose tissue, which supports a role for glucose oxidation in brown fat thermogenesis.


Assuntos
Tecido Adiposo Marrom , Glucose , Tecido Adiposo Branco , Animais , Temperatura Baixa , Fluordesoxiglucose F18 , Camundongos , Termogênese
12.
Nat Metab ; 2(11): 1248-1264, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33106689

RESUMO

In addition to fatty acids, glucose and lactate are important myocardial substrates under physiologic and stress conditions. They are metabolized to pyruvate, which enters mitochondria via the mitochondrial pyruvate carrier (MPC) for citric acid cycle metabolism. In the present study, we show that MPC-mediated mitochondrial pyruvate utilization is essential for the partitioning of glucose-derived cytosolic metabolic intermediates, which modulate myocardial stress adaptation. Mice with cardiomyocyte-restricted deletion of subunit 1 of MPC (cMPC1-/-) developed age-dependent pathologic cardiac hypertrophy, transitioning to a dilated cardiomyopathy and premature death. Hypertrophied hearts accumulated lactate, pyruvate and glycogen, and displayed increased protein O-linked N-acetylglucosamine, which was prevented by increasing availability of non-glucose substrates in vivo by a ketogenic diet (KD) or a high-fat diet, which reversed the structural, metabolic and functional remodelling of non-stressed cMPC1-/- hearts. Although concurrent short-term KDs did not rescue cMPC1-/- hearts from rapid decompensation and early mortality after pressure overload, 3 weeks of a KD before transverse aortic constriction was sufficient to rescue this phenotype. Together, our results highlight the centrality of pyruvate metabolism to myocardial metabolism and function.


Assuntos
Adaptação Fisiológica/fisiologia , Proteínas de Transporte de Ânions/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Miocárdio/metabolismo , Estresse Fisiológico/fisiologia , Adaptação Fisiológica/genética , Animais , Proteínas de Transporte de Ânions/genética , Cardiomegalia/diagnóstico por imagem , Cardiomegalia/genética , Cardiomegalia/metabolismo , Cardiomiopatia Dilatada/genética , Cardiomiopatia Dilatada/metabolismo , Constrição Patológica , Citosol/metabolismo , Dieta Hiperlipídica , Dieta Cetogênica , Ecocardiografia , Técnicas In Vitro , Camundongos , Camundongos Knockout , Mitocôndrias Cardíacas/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/genética , Miócitos Cardíacos/metabolismo , Ácido Pirúvico/metabolismo , Estresse Fisiológico/genética
13.
Elife ; 92020 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-32804083

RESUMO

Cells harbor two systems for fatty acid synthesis, one in the cytoplasm (catalyzed by fatty acid synthase, FASN) and one in the mitochondria (mtFAS). In contrast to FASN, mtFAS is poorly characterized, especially in higher eukaryotes, with the major product(s), metabolic roles, and cellular function(s) being essentially unknown. Here we show that hypomorphic mtFAS mutant mouse skeletal myoblast cell lines display a severe loss of electron transport chain (ETC) complexes and exhibit compensatory metabolic activities including reductive carboxylation. This effect on ETC complexes appears to be independent of protein lipoylation, the best characterized function of mtFAS, as mutants lacking lipoylation have an intact ETC. Finally, mtFAS impairment blocks the differentiation of skeletal myoblasts in vitro. Together, these data suggest that ETC activity in mammals is profoundly controlled by mtFAS function, thereby connecting anabolic fatty acid synthesis with the oxidation of carbon fuels.


Assuntos
Complexo de Proteínas da Cadeia de Transporte de Elétrons/metabolismo , Ácidos Graxos/biossíntese , Mitocôndrias/metabolismo , Mioblastos/fisiologia , Animais , Diferenciação Celular , Linhagem Celular , Complexo de Proteínas da Cadeia de Transporte de Elétrons/genética , Células HEK293 , Humanos , Lipoilação/genética , Camundongos , Oxirredução
14.
Elife ; 92020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32795388

RESUMO

Brown adipose tissue (BAT) is composed of thermogenic cells that convert chemical energy into heat to maintain a constant body temperature and counteract metabolic disease. The metabolic adaptations required for thermogenesis are not fully understood. Here, we explore how steady state levels of metabolic intermediates are altered in brown adipose tissue in response to cold exposure. Transcriptome and metabolome analysis revealed changes in pathways involved in amino acid, glucose, and TCA cycle metabolism. Using isotopic labeling experiments, we found that activated brown adipocytes increased labeling of pyruvate and TCA cycle intermediates from U13C-glucose. Although glucose oxidation has been implicated as being essential for thermogenesis, its requirement for efficient thermogenesis has not been directly tested. We show that mitochondrial pyruvate uptake is essential for optimal thermogenesis, as conditional deletion of Mpc1 in brown adipocytes leads to impaired cold adaptation. Isotopic labeling experiments using U13C-glucose showed that loss of MPC1 led to impaired labeling of TCA cycle intermediates. Loss of MPC1 in BAT increased 3-hydroxybutyrate levels in blood and BAT in response to the cold, suggesting that ketogenesis provides an alternative fuel source to compensate. Collectively, these studies highlight that complete glucose oxidation is essential for optimal brown fat thermogenesis.


Assuntos
Tecido Adiposo Marrom/fisiologia , Proteínas de Transporte de Ânions/genética , Temperatura Baixa , Glucose/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/genética , Transportadores de Ácidos Monocarboxílicos/genética , Termogênese , Adipócitos Marrons/metabolismo , Animais , Proteínas de Transporte de Ânions/metabolismo , Masculino , Metabolômica , Camundongos , Camundongos Endogâmicos C57BL , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Transportadores de Ácidos Monocarboxílicos/metabolismo , Oxirredução , Soro/química
15.
IUCrJ ; 7(Pt 4): 693-706, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32695416

RESUMO

DHTKD1 is a lesser-studied E1 enzyme among the family of 2-oxoacid de-hydrogenases. In complex with E2 (di-hydro-lipo-amide succinyltransferase, DLST) and E3 (dihydrolipo-amide de-hydrogenase, DLD) components, DHTKD1 is involved in lysine and tryptophan catabolism by catalysing the oxidative de-carboxyl-ation of 2-oxoadipate (2OA) in mitochondria. Here, the 1.9 Šresolution crystal structure of human DHTKD1 is solved in complex with the thi-amine diphosphate co-factor. The structure reveals how the DHTKD1 active site is modelled upon the well characterized homologue 2-oxoglutarate (2OG) de-hydrogenase but engineered specifically to accommodate its preference for the longer substrate of 2OA over 2OG. A 4.7 Šresolution reconstruction of the human DLST catalytic core is also generated by single-particle electron microscopy, revealing a 24-mer cubic scaffold for assembling DHTKD1 and DLD protomers into a megacomplex. It is further demonstrated that missense DHTKD1 variants causing the inborn error of 2-amino-adipic and 2-oxoadipic aciduria impact on the complex formation, either directly by disrupting the interaction with DLST, or indirectly through destabilizing the DHTKD1 protein. This study provides the starting framework for developing DHTKD1 modulators to probe the intricate mitochondrial energy metabolism.

16.
Hepatol Commun ; 4(5): 696-707, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32363320

RESUMO

Hyperactivation of sterol regulatory element binding protein 1c (SREBP-1c), which transcriptionally induces expression of enzymes responsible for de novo lipogenesis and triglyceride (TG) formation, is implicated in nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) pathogenesis. Posttranslational SREBP-1c maturation and activation is stimulated by the protein per-arnt-sim kinase (PASK). PASK-knockout mice are phenotypically normal on a conventional diet but exhibit decreased hypertriglyceridemia, insulin resistance, and hepatic steatosis on a high-fat diet. We investigated the effects of pharmacologic PASK inhibition using BioE-1115, a selective and potent oral PASK inhibitor, in Zucker fatty (fa)/fa) rats, a genetic model of obesity, dyslipidemia, and insulin resistance, and in a dietary murine model of NAFLD/NASH. Female Zucker (fa/fa) rats and lean littermate (fa/+) controls received BioE-1115 (3-100 mg/kg/day) and/or omega-3 fatty acids, and blood glucose, hemoglobin A1c, glucose tolerance, insulin, and serum TG were measured. C57BL/6J mice fed a high-fat/high-fructose diet (HF-HFrD) were treated with BioE-1115 (100 mg/kg/day) or vehicle. Body weight and fasting glucose were measured regularly; serum TG, body and organ weights, and liver TG and histology were assessed at sacrifice. Messenger RNA (mRNA) abundance of SREBP-1c target genes was measured in both models. In Zucker rats, BioE-1115 treatment produced significant dose-dependent reductions in blood glucose, insulin, and TG (all greater than omega-3 fatty acids) and dose dependently restored insulin sensitivity assessed by glucose tolerance testing. In HF-HFrD mice, BioE-1115 reduced body weight, liver weight, fasting blood glucose, serum TGs, hepatic TG, hepatic fibrosis, hepatocyte vacuolization, and bile duct hyperplasia. BioE-1115 reduced SREBP-1c target mRNA transcripts in both models. Conclusion: PASK inhibition mitigates many adverse metabolic consequences associated with an HF-HFrD and reduces hepatic fat content and fibrosis. This suggests that inhibition of PASK is an attractive therapeutic strategy for NAFLD/NASH treatment.

17.
Circulation ; 142(3): 259-274, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32351122

RESUMO

BACKGROUND: Significant improvements in myocardial structure and function have been reported in some patients with advanced heart failure (termed responders [R]) following left ventricular assist device (LVAD)-induced mechanical unloading. This therapeutic strategy may alter myocardial energy metabolism in a manner that reverses the deleterious metabolic adaptations of the failing heart. Specifically, our previous work demonstrated a post-LVAD dissociation of glycolysis and oxidative-phosphorylation characterized by induction of glycolysis without subsequent increase in pyruvate oxidation through the tricarboxylic acid cycle. The underlying mechanisms responsible for this dissociation are not well understood. We hypothesized that the accumulated glycolytic intermediates are channeled into cardioprotective and repair pathways, such as the pentose-phosphate pathway and 1-carbon metabolism, which may mediate myocardial recovery in R. METHODS: We prospectively obtained paired left ventricular apical myocardial tissue from nonfailing donor hearts as well as R and nonresponders at LVAD implantation (pre-LVAD) and transplantation (post-LVAD). We conducted protein expression and metabolite profiling and evaluated mitochondrial structure using electron microscopy. RESULTS: Western blot analysis shows significant increase in rate-limiting enzymes of pentose-phosphate pathway and 1-carbon metabolism in post-LVAD R (post-R) as compared with post-LVAD nonresponders (post-NR). The metabolite levels of these enzyme substrates, such as sedoheptulose-6-phosphate (pentose phosphate pathway) and serine and glycine (1-carbon metabolism) were also decreased in Post-R. Furthermore, post-R had significantly higher reduced nicotinamide adenine dinucleotide phosphate levels, reduced reactive oxygen species levels, improved mitochondrial density, and enhanced glycosylation of the extracellular matrix protein, α-dystroglycan, all consistent with enhanced pentose-phosphate pathway and 1-carbon metabolism that correlated with the observed myocardial recovery. CONCLUSIONS: The recovering heart appears to direct glycolytic metabolites into pentose-phosphate pathway and 1-carbon metabolism, which could contribute to cardioprotection by generating reduced nicotinamide adenine dinucleotide phosphate to enhance biosynthesis and by reducing oxidative stress. These findings provide further insights into mechanisms responsible for the beneficial effect of glycolysis induction during the recovery of failing human hearts after mechanical unloading.


Assuntos
Glucose/metabolismo , Insuficiência Cardíaca/metabolismo , Miocárdio/metabolismo , Comorbidade , Metabolismo Energético , Glicólise , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/fisiopatologia , Ventrículos do Coração/fisiopatologia , Coração Auxiliar , Humanos , Redes e Vias Metabólicas , Metaboloma , Metabolômica/métodos , Oxirredução , Volume Sistólico
18.
EMBO Rep ; 21(5): e50071, 2020 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-32329174

RESUMO

The metabolic compartmentalization enabled by mitochondria is key feature of many cellular processes such as energy conversion to ATP production, redox balance, and the biosynthesis of heme, urea, nucleotides, lipids, and others. For a majority of these functions, metabolites need to be transported across the impermeable inner mitochondrial membrane by dedicated carrier proteins. Here, we examine the substrates, structural features, and human health implications of four mitochondrial metabolite carrier families: the SLC25A family, the mitochondrial ABCB transporters, the mitochondrial pyruvate carrier (MPC), and the sideroflexin proteins.


Assuntos
Proteínas de Transporte da Membrana Mitocondrial , Membranas Mitocondriais , Transporte Biológico , Proteínas de Transporte/metabolismo , Humanos , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/genética , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Membranas Mitocondriais/metabolismo
19.
Cell Rep ; 30(9): 2889-2899.e6, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32130894

RESUMO

Metabolic pathways regulate T cell development and function, but many remain understudied. Recently, the mitochondrial pyruvate carrier (MPC) was identified as the transporter that mediates pyruvate entry into mitochondria, promoting pyruvate oxidation. Here we find that deleting Mpc1, an obligate MPC subunit, in the hematopoietic system results in a specific reduction in peripheral αß T cell numbers. MPC1-deficient T cells have defective thymic development at the ß-selection, intermediate single positive (ISP)-to-double-positive (DP), and positive selection steps. We find that early thymocytes deficient in MPC1 display alterations to multiple pathways involved in T cell development. This results in preferred escape of more activated T cells. Finally, mice with hematopoietic deletion of Mpc1 are more susceptible to experimental autoimmune encephalomyelitis. Altogether, our study demonstrates that pyruvate oxidation by T cell precursors is necessary for optimal αß T cell development and that its deficiency results in reduced but activated peripheral T cell populations.


Assuntos
Proteínas de Transporte de Ânions/metabolismo , Homeostase , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Transportadores de Ácidos Monocarboxílicos/metabolismo , Linfócitos T/metabolismo , Timo/crescimento & desenvolvimento , Timo/metabolismo , Animais , Proteínas de Transporte de Ânions/deficiência , Deleção de Genes , Glicólise , Hematopoese , Humanos , Inflamação/patologia , Células Jurkat , Contagem de Linfócitos , Camundongos , Camundongos Endogâmicos C57BL , Proteínas de Transporte da Membrana Mitocondrial/deficiência , Transportadores de Ácidos Monocarboxílicos/deficiência , Oxirredução , Fosforilação Oxidativa , Ácido Pirúvico/metabolismo , Timócitos/metabolismo
20.
J Immunol ; 204(8): 2064-2075, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32161096

RESUMO

Aging-related chronic inflammation is a risk factor for many human disorders through incompletely understood mechanisms. Aged mice deficient in microRNA (miRNA/miR)-146a succumb to life-shortening chronic inflammation. In this study, we report that miR-155 in T cells contributes to shortened lifespan of miR-146a-/- mice. Using single-cell RNA sequencing and flow cytometry, we found that miR-155 promotes the activation of effector T cell populations, including T follicular helper cells, and increases germinal center B cells and autoantibodies in mice aged over 15 months. Mechanistically, aerobic glycolysis genes are elevated in T cells during aging, and upon deletion of miR-146a, in a T cell miR-155-dependent manner. Finally, skewing T cell metabolism toward aerobic glycolysis by deleting mitochondrial pyruvate carrier recapitulates age-dependent T cell phenotypes observed in miR-146a-/- mice, revealing the sufficiency of metabolic reprogramming to influence immune cell functions during aging. Altogether, these data indicate that T cell-specific miRNAs play pivotal roles in regulating lifespan through their influences on inflammaging.


Assuntos
Modelos Animais de Doenças , Inflamação/genética , Longevidade/genética , MicroRNAs/genética , Linfócitos T/metabolismo , Fatores Etários , Animais , Feminino , Inflamação/imunologia , Inflamação/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Linfócitos T/imunologia , Linfócitos T/patologia
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