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1.
Oxid Med Cell Longev ; 2020: 6401341, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33014275

RESUMO

Human SARS-CoV-2 infection is characterized by a high mortality rate due to some patients developing a large innate immune response associated with a cytokine storm and acute respiratory distress syndrome (ARDS). This is characterized at the molecular level by decreased energy metabolism, altered redox state, oxidative damage, and cell death. Therapies that increase levels of (R)-beta-hydroxybutyrate (R-BHB), such as the ketogenic diet or consuming exogenous ketones, should restore altered energy metabolism and redox state. R-BHB activates anti-inflammatory GPR109A signaling and inhibits the NLRP3 inflammasome and histone deacetylases, while a ketogenic diet has been shown to protect mice from influenza virus infection through a protective γδ T cell response and by increasing electron transport chain gene expression to restore energy metabolism. During a virus-induced cytokine storm, metabolic flexibility is compromised due to increased levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) that damage, downregulate, or inactivate many enzymes of central metabolism including the pyruvate dehydrogenase complex (PDC). This leads to an energy and redox crisis that decreases B and T cell proliferation and results in increased cytokine production and cell death. It is hypothesized that a moderately high-fat diet together with exogenous ketone supplementation at the first signs of respiratory distress will increase mitochondrial metabolism by bypassing the block at PDC. R-BHB-mediated restoration of nucleotide coenzyme ratios and redox state should decrease ROS and RNS to blunt the innate immune response and the associated cytokine storm, allowing the proliferation of cells responsible for adaptive immunity. Limitations of the proposed therapy include the following: it is unknown if human immune and lung cell functions are enhanced by ketosis, the risk of ketoacidosis must be assessed prior to initiating treatment, and permissive dietary fat and carbohydrate levels for exogenous ketones to boost immune function are not yet established. The third limitation could be addressed by studies with influenza-infected mice. A clinical study is warranted where COVID-19 patients consume a permissive diet combined with ketone ester to raise blood ketone levels to 1 to 2 mM with measured outcomes of symptom severity, length of infection, and case fatality rate.


Assuntos
Infecções por Coronavirus/terapia , Síndrome da Liberação de Citocina/terapia , Dieta Cetogênica/métodos , Cetonas/administração & dosagem , Pneumonia Viral/terapia , Ácido 3-Hidroxibutírico/metabolismo , Imunidade Adaptativa , Animais , Betacoronavirus , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/metabolismo , Síndrome da Liberação de Citocina/imunologia , Síndrome da Liberação de Citocina/metabolismo , Metabolismo Energético , Humanos , Imunidade Inata , Cetonas/metabolismo , Oxirredução , Pandemias , Pneumonia Viral/imunologia , Pneumonia Viral/metabolismo
2.
Tumour Biol ; 42(10): 1010428320965284, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33028168

RESUMO

Glucose, as the main consuming nutrient of the body, faces different destinies in cancer cells. Glycolysis, oxidative phosphorylation, and pentose phosphate pathways produce different glucose-derived metabolites and thus affect cells' bioenergetics differently. Tumor cells' dependency to aerobic glycolysis and other cancer-specific metabolism changes are known as the cancer hallmarks, distinct cancer cells from normal cells. Therefore, these tumor-specific characteristics receive the limelight as targets for cancer therapy. Glutamine, serine, and fatty acid oxidation together with 5-lipoxygenase are main pathways that have attracted lots of attention for cancer therapy. In this review, we not only discuss different tumor metabolism aspects but also discuss the metabolism roles in the promotion of cancer cells at different stages and their difference with normal cells. Besides, we dissect the inhibitors potential in blocking the main metabolic pathways to introduce the effective and non-effective inhibitors in the field.


Assuntos
Antineoplásicos/uso terapêutico , Metabolismo Energético/efeitos dos fármacos , Terapia de Alvo Molecular , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Medicina de Precisão , Antineoplásicos/farmacologia , Ciclo do Ácido Cítrico/efeitos dos fármacos , Metabolismo Energético/efeitos da radiação , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Glicólise/efeitos dos fármacos , Humanos , Terapia de Alvo Molecular/métodos , Neoplasias/etiologia , Neoplasias/patologia , Fosforilação Oxidativa/efeitos dos fármacos , Via de Pentose Fosfato/efeitos dos fármacos , Medicina de Precisão/métodos
4.
Nat Commun ; 11(1): 4664, 2020 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-32938919

RESUMO

Cardiorenal syndrome type 4 (CRS4) is a common complication of chronic kidney disease (CKD), but the pathogenic mechanisms remain elusive. Here we report that morphological and functional changes in myocardial mitochondria are observed in CKD mice, especially decreases in oxidative phosphorylation and fatty acid metabolism. High phosphate (HP), a hallmark of CKD, contributes to myocardial energy metabolism dysfunction by downregulating peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α). Furthermore, the transcriptional factor interferon regulatory factor 1 (IRF1) is revealed as the key molecule upregulated by HP through histone H3K9 acetylation, and responsible for the HP-mediated transcriptional inhibition of PGC1α by directly binding to its promoter region. Conversely, restoration of PGC1α expression or genetic knockdown of IRF1 significantly attenuates HP-induced alterations in vitro and in vivo. These findings demonstrate that IRF1-PGC1α axis-mediated myocardial energy metabolism remodeling plays a crucial role in the pathogenesis of CRS4.


Assuntos
Síndrome Cardiorrenal/metabolismo , Fator Regulador 1 de Interferon/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Síndrome Cardiorrenal/patologia , Modelos Animais de Doenças , Regulação para Baixo , Metabolismo Energético , Técnicas de Silenciamento de Genes , Taxa de Filtração Glomerular , Glucuronidase/genética , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/metabolismo , Humanos , Fator Regulador 1 de Interferon/genética , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Mitocôndrias Cardíacas/metabolismo , Mitocôndrias Cardíacas/patologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Fosfatos/metabolismo , Regiões Promotoras Genéticas , Ratos , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/metabolismo , Adulto Jovem
5.
Nat Commun ; 11(1): 4706, 2020 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-32943618

RESUMO

Yeast physiology is temporally regulated, this becomes apparent under nutrient-limited conditions and results in respiratory oscillations (YROs). YROs share features with circadian rhythms and interact with, but are independent of, the cell division cycle. Here, we show that YROs minimise energy expenditure by restricting protein synthesis until sufficient resources are stored, while maintaining osmotic homeostasis and protein quality control. Although nutrient supply is constant, cells sequester and store metabolic resources via increased transport, autophagy and biomolecular condensation. Replete stores trigger increased H+ export which stimulates TORC1 and liberates proteasomes, ribosomes, chaperones and metabolic enzymes from non-membrane bound compartments. This facilitates translational bursting, liquidation of storage carbohydrates, increased ATP turnover, and the export of osmolytes. We propose that dynamic regulation of ion transport and metabolic plasticity are required to maintain osmotic and protein homeostasis during remodelling of eukaryotic proteomes, and that bioenergetic constraints selected for temporal organisation that promotes oscillatory behaviour.


Assuntos
Metabolismo Energético/fisiologia , Células Eucarióticas/fisiologia , Proteostase/fisiologia , Autofagia/fisiologia , Reatores Biológicos , Ritmo Circadiano , Glicogênio/metabolismo , Resposta ao Choque Térmico , Ionomicina , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Metabolômica , Chaperonas Moleculares , Concentração Osmolar , Pressão Osmótica , Oxigênio/metabolismo , Biossíntese de Proteínas , Processamento de Proteína Pós-Traducional , Proteoma , Proteômica , Ribossomos , Leveduras/fisiologia
6.
Oxid Med Cell Longev ; 2020: 8384742, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32963703

RESUMO

H2 has shown anti-inflammatory and antioxidant ability in many clinical trials, and its application is recommended in the latest Chinese novel coronavirus pneumonia (NCP) treatment guidelines. Clinical experiments have revealed the surprising finding that H2 gas may protect the lungs and extrapulmonary organs from pathological stimuli in NCP patients. The potential mechanisms underlying the action of H2 gas are not clear. H2 gas may regulate the anti-inflammatory and antioxidant activity, mitochondrial energy metabolism, endoplasmic reticulum stress, the immune system, and cell death (apoptosis, autophagy, pyroptosis, ferroptosis, and circadian clock, among others) and has therapeutic potential for many systemic diseases. This paper reviews the basic research and the latest clinical applications of H2 gas in multiorgan system diseases to establish strategies for the clinical treatment for various diseases.


Assuntos
Hidrogênio/administração & dosagem , Hidrogênio/farmacologia , Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Betacoronavirus , Infecções por Coronavirus/terapia , Metabolismo Energético/efeitos dos fármacos , Humanos , Estresse Oxidativo/efeitos dos fármacos , Pandemias , Pneumonia Viral/terapia , Substâncias Protetoras/farmacologia
8.
Vasc Health Risk Manag ; 16: 353-365, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32982263

RESUMO

Among the vast number of noncommunicable diseases encountered worldwide, cardiovascular diseases accounted for about 17.8 million deaths in 2017 and ischemic heart disease (IHD) remains the single-largest cause of death in countries across all income groups. Because conventional medications are not without shortcomings and patients still refractory to these medications, scientific investigation is ongoing to advance the management of IHD, and shows a great promise for better treatment modalities, but additional research can warrant improvement in terms of the quality of life of patients. Metabolic modulation is one promising strategy for the treatment of IHD, because alterations in energy metabolism are involved in progression of the disease. Therefore, the purpose of this review was to strengthen attention toward the use of metabolic modulators and to review the current level of knowledge on cardiac energy metabolic pathways.


Assuntos
Fármacos Cardiovasculares/uso terapêutico , Metabolismo Energético/efeitos dos fármacos , Mitocôndrias Cardíacas/efeitos dos fármacos , Isquemia Miocárdica/tratamento farmacológico , Miócitos Cardíacos/efeitos dos fármacos , Animais , Humanos , Mitocôndrias Cardíacas/metabolismo , Terapia de Alvo Molecular , Isquemia Miocárdica/metabolismo , Isquemia Miocárdica/fisiopatologia , Miócitos Cardíacos/metabolismo
9.
Nat Commun ; 11(1): 4837, 2020 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-32973183

RESUMO

ATP synthesis and thermogenesis are two critical outputs of mitochondrial respiration. How these outputs are regulated to balance the cellular requirement for energy and heat is largely unknown. Here we show that major facilitator superfamily domain containing 7C (MFSD7C) uncouples mitochondrial respiration to switch ATP synthesis to thermogenesis in response to heme. When heme levels are low, MSFD7C promotes ATP synthesis by interacting with components of the electron transport chain (ETC) complexes III, IV, and V, and destabilizing sarcoendoplasmic reticulum Ca2+-ATPase 2b (SERCA2b). Upon heme binding to the N-terminal domain, MFSD7C dissociates from ETC components and SERCA2b, resulting in SERCA2b stabilization and thermogenesis. The heme-regulated switch between ATP synthesis and thermogenesis enables cells to match outputs of mitochondrial respiration to their metabolic state and nutrient supply, and represents a cell intrinsic mechanism to regulate mitochondrial energy metabolism.


Assuntos
Trifosfato de Adenosina/metabolismo , Heme/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Mitocôndrias/metabolismo , Receptores Virais/metabolismo , Termogênese/fisiologia , Animais , Deficiência de Citocromo-c Oxidase , Complexo III da Cadeia de Transporte de Elétrons , Complexo IV da Cadeia de Transporte de Elétrons , Metabolismo Energético/fisiologia , Técnicas de Inativação de Genes , Células HEK293 , Humanos , Proteínas de Membrana Transportadoras/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Membranas Mitocondriais/metabolismo , Domínios Proteicos , Receptores Virais/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Transdução de Sinais , Células THP-1
10.
Mar Environ Res ; 160: 104985, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32907723

RESUMO

This study aims at (1) experimentally estimating first sexual maturation of the European sardine S. pilchardus, (2) using the results to calibrate existing bioenergetic models. During the 183 days-experiment, fish growth and body condition were assessed by biometry, and gonads were weighed when present. Age, wet weight and total length at first maturity were estimated at 262 days, 10.79 ± 0.75 g, and 11.26 ± 0.21 cm, respectively. Including these traits in biphasic Von Bertalanffy models did not significantly improve simulations for either length or weight data, meaning that energy allocation was not impacted by these traits. The implementation of the results in the Dynamic Energy Budget (DEB) calibration procedure strengthened the parameter set of the existing model, but resulted in significant changes in the energy allocation. Our results are a first step that will allow the design of new experiments to further quantify maturation and reproduction rates in diverse environmental conditions, consolidating DEB model calibration.


Assuntos
Peixes , Alimentos Marinhos , Animais , Metabolismo Energético , Peixes/crescimento & desenvolvimento , Gônadas
11.
Nat Commun ; 11(1): 4509, 2020 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-32908151

RESUMO

Glycolysis is one of the primordial pathways of metabolism, playing a pivotal role in energy metabolism and biosynthesis. Glycolytic enzymes are known to form transient multi-enzyme assemblies. Here we examine the wider protein-protein interactions of plant glycolytic enzymes and reveal a moonlighting role for specific glycolytic enzymes in mediating the co-localization of mitochondria and chloroplasts. Knockout mutation of phosphoglycerate mutase or enolase resulted in a significantly reduced association of the two organelles. We provide evidence that phosphoglycerate mutase and enolase form a substrate-channelling metabolon which is part of a larger complex of proteins including pyruvate kinase. These results alongside a range of genetic complementation experiments are discussed in the context of our current understanding of chloroplast-mitochondrial interactions within photosynthetic eukaryotes.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Cloroplastos/enzimologia , Glicólise/fisiologia , Mitocôndrias/enzimologia , Arabidopsis/citologia , Proteínas de Arabidopsis/genética , Metabolismo Energético/fisiologia , Mutação , Fosfoglicerato Mutase/genética , Fosfoglicerato Mutase/metabolismo , Fosfopiruvato Hidratase/genética , Fosfopiruvato Hidratase/metabolismo , Fotossíntese/fisiologia , Plantas Geneticamente Modificadas , Mapeamento de Interação de Proteínas , Mapas de Interação de Proteínas/fisiologia , Piruvato Quinase/genética , Piruvato Quinase/metabolismo
12.
Nat Commun ; 11(1): 4416, 2020 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-32887881

RESUMO

Despite the clear association between myocardial injury, heart failure and depressed myocardial energetics, little is known about upstream signals responsible for remodeling myocardial metabolism after pathological stress. Here, we report increased mitochondrial calmodulin kinase II (CaMKII) activation and left ventricular dilation in mice one week after myocardial infarction (MI) surgery. By contrast, mice with genetic mitochondrial CaMKII inhibition are protected from left ventricular dilation and dysfunction after MI. Mice with myocardial and mitochondrial CaMKII overexpression (mtCaMKII) have severe dilated cardiomyopathy and decreased ATP that causes elevated cytoplasmic resting (diastolic) Ca2+ concentration and reduced mechanical performance. We map a metabolic pathway that rescues disease phenotypes in mtCaMKII mice, providing insights into physiological and pathological metabolic consequences of CaMKII signaling in mitochondria. Our findings suggest myocardial dilation, a disease phenotype lacking specific therapies, can be prevented by targeted replacement of mitochondrial creatine kinase or mitochondrial-targeted CaMKII inhibition.


Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Cardiomiopatia Dilatada/metabolismo , Infarto do Miocárdio/fisiopatologia , Animais , Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Metabolismo Energético/genética , Metabolismo Energético/fisiologia , Insuficiência Cardíaca/metabolismo , Ventrículos do Coração/fisiopatologia , Camundongos , Camundongos Transgênicos , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Infarto do Miocárdio/cirurgia , Transdução de Sinais
13.
Nat Commun ; 11(1): 4313, 2020 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-32855402

RESUMO

It has been suggested that beige fat thermogenesis is tightly controlled by epigenetic regulators that sense environmental cues such as temperature. Here, we report that subcutaneous adipose expression of the DNA demethylase TET1 is suppressed by cold and other stimulators of beige adipocyte thermogenesis. TET1 acts as an autonomous repressor of key thermogenic genes, including Ucp1 and Ppargc1a, in beige adipocytes. Adipose-selective Tet1 knockout mice generated by using Fabp4-Cre improves cold tolerance and increases energy expenditure and protects against diet-induced obesity and insulin resistance. Moreover, the suppressive role of TET1 in the thermogenic gene regulation of beige adipocytes is largely DNA demethylase-independent. Rather, TET1 coordinates with HDAC1 to mediate the epigenetic changes to suppress thermogenic gene transcription. Taken together, TET1 is a potent beige-selective epigenetic breaker of the thermogenic gene program. Our findings may lead to a therapeutic strategy to increase energy expenditure in obesity and related metabolic disorders.


Assuntos
Adipócitos Bege/metabolismo , Proteínas de Ligação a DNA/metabolismo , Epigênese Genética , Obesidade/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Termogênese/genética , Animais , Calorimetria Indireta , Linhagem Celular , Temperatura Baixa/efeitos adversos , Proteínas de Ligação a DNA/genética , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Metabolismo Energético/genética , Regulação da Expressão Gênica/fisiologia , Células HEK293 , Humanos , Resistência à Insulina/genética , Masculino , Camundongos , Camundongos Knockout , Obesidade/etiologia , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Proteínas Proto-Oncogênicas/genética , RNA-Seq , Gordura Subcutânea/citologia , Gordura Subcutânea/metabolismo , Proteína Desacopladora 1/metabolismo
14.
PLoS One ; 15(8): e0236457, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790682

RESUMO

Transgenic mice with selective induction of calreticulin transgene expression in cardiomyocytes (CardiacCRT+) were analyzed. CardiacCRT+ cardiomyocytes showed increased contractility and Ca2+ transients. Yet, in vivo assessment of cardiac performance, and ischemic tolerance of CardiacCRT+ mice demonstrated right ventricle dilation and reduced cardiac output, increased QT interval and decreased P amplitude. Paradoxically, ex vivo working hearts from CardiacCRT+ mice showed enhanced ischemic cardio-protection and cardiac efficiency. Under aerobic conditions, CardiacCRT+ hearts showed less efficient cardiac function than sham control hearts due to an increased ATP production from glycolysis relative to glucose oxidation. During reperfusion, this inefficiency was reversed, with CardiacCRT+ hearts exhibiting better functional recovery and increased cardiac efficiency compared to sham control hearts. On the other hand, mechanical stretching of isolated cardiac fibroblasts activated the IRE1α branch of the unfolded protein response pathway as well as induction of Col1A2 and TGFß gene expression ex vivo, which were all suppressed by tauroursodeoxycholic acid.


Assuntos
Calreticulina/metabolismo , Contração Miocárdica , Isquemia Miocárdica/metabolismo , Miócitos Cardíacos/metabolismo , Animais , Calreticulina/genética , Células Cultivadas , Metabolismo Energético , Frequência Cardíaca , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Isquemia Miocárdica/genética , Isquemia Miocárdica/fisiopatologia , Miócitos Cardíacos/patologia , Regulação para Cima
15.
Nat Commun ; 11(1): 4046, 2020 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-32792488

RESUMO

2-oxoglutarate (2-OG or α-ketoglutarate) relates mitochondrial metabolism to cell function by modulating the activity of 2-OG dependent dioxygenases involved in the hypoxia response and DNA/histone modifications. However, metabolic pathways that regulate these oxygen and 2-OG sensitive enzymes remain poorly understood. Here, using CRISPR Cas9 genome-wide mutagenesis to screen for genetic determinants of 2-OG levels, we uncover a redox sensitive mitochondrial lipoylation pathway, dependent on the mitochondrial hydrolase ABHD11, that signals changes in mitochondrial 2-OG metabolism to 2-OG dependent dioxygenase function. ABHD11 loss or inhibition drives a rapid increase in 2-OG levels by impairing lipoylation of the 2-OG dehydrogenase complex (OGDHc)-the rate limiting step for mitochondrial 2-OG metabolism. Rather than facilitating lipoate conjugation, ABHD11 associates with the OGDHc and maintains catalytic activity of lipoyl domain by preventing the formation of lipoyl adducts, highlighting ABHD11 as a regulator of functional lipoylation and 2-OG metabolism.


Assuntos
Complexo Cetoglutarato Desidrogenase/metabolismo , Ácidos Cetoglutáricos/metabolismo , Mitocôndrias/metabolismo , Mutagênese/fisiologia , Serina Proteases/metabolismo , Metabolismo Energético/genética , Metabolismo Energético/fisiologia , Células HeLa , Humanos , Complexo Cetoglutarato Desidrogenase/genética , Modelos Biológicos , Mutagênese/genética , Serina Proteases/genética
16.
Nat Commun ; 11(1): 3794, 2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32732906

RESUMO

Defective rhythmic metabolism is associated with high-fat high-caloric diet (HFD) feeding, ageing and obesity; however, the neural basis underlying HFD effects on diurnal metabolism remains elusive. Here we show that deletion of BMAL1, a core clock gene, in paraventricular hypothalamic (PVH) neurons reduces diurnal rhythmicity in metabolism, causes obesity and diminishes PVH neuron activation in response to fast-refeeding. Animal models mimicking deficiency in PVH neuron responsiveness, achieved through clamping PVH neuron activity at high or low levels, both show obesity and reduced diurnal rhythmicity in metabolism. Interestingly, the PVH exhibits BMAL1-controlled rhythmic expression of GABA-A receptor γ2 subunit, and dampening rhythmicity of GABAergic input to the PVH reduces diurnal rhythmicity in metabolism and causes obesity. Finally, BMAL1 deletion blunts PVH neuron responses to external stressors, an effect mimicked by HFD feeding. Thus, BMAL1-driven PVH neuron responsiveness in dynamic activity changes involving rhythmic GABAergic neurotransmission mediates diurnal rhythmicity in metabolism and is implicated in diet-induced obesity.


Assuntos
Fatores de Transcrição ARNTL/genética , Ritmo Circadiano/fisiologia , Obesidade/patologia , Núcleo Hipotalâmico Paraventricular/metabolismo , Receptores de GABA-A/metabolismo , Animais , Ritmo Circadiano/genética , Dieta Hiperlipídica , Metabolismo Energético/fisiologia , Comportamento Alimentar/fisiologia , Camundongos , Camundongos Knockout , Neurônios/fisiologia , Obesidade/genética , Núcleo Hipotalâmico Paraventricular/citologia
17.
PLoS Comput Biol ; 16(8): e1007966, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32760072

RESUMO

Protein activity is often regulated by ligand binding or by post-translational modifications such as phosphorylation. Moreover, proteins that are regulated in this way often contain multiple ligand binding sites or modification sites, which can operate to create an ultrasensitive dose response. Here, we consider the contribution of the individual modification/binding sites to the activation process, and how their individual values affect the ultrasensitive behavior of the overall system. We use a generalized Monod-Wyman-Changeux (MWC) model that allows for variable conformational free energy contributions from distinct sites, and associate a so-called activation parameter to each site. Our analysis shows that the ultrasensitivity generally increases as the conformational free energy contribution from one or more sites is strengthened. Furthermore, ultrasensitivity depends on the mean of the activation parameters and not on their variability. In some cases, we find that the best way to maximize ultrasensitivity is to make the contribution from all sites as strong as possible. These results provide insights into the performance objectives of multiple modification/binding sites and thus help gain a greater understanding of signaling and its role in diseases.


Assuntos
Sítios de Ligação/fisiologia , Metabolismo Energético/fisiologia , Processamento de Proteína Pós-Traducional/fisiologia , Proteínas , Transdução de Sinais/fisiologia , Ligantes , Modelos Biológicos , Fosforilação/fisiologia , Conformação Proteica , Subunidades Proteicas , Proteínas/química , Proteínas/metabolismo , Termodinâmica
18.
Proc Biol Sci ; 287(1933): 20200431, 2020 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-32811308

RESUMO

Ground contact duration and stride frequency each affect muscle metabolism and help scientists link walking and running biomechanics to metabolic energy expenditure. While these parameters are often used independently, the product of ground contact duration and stride frequency (i.e. duty factor) may affect muscle contractile mechanics. Here, we sought to separate the metabolic influence of the duration of active force production, cycle frequency and duty factor. Human participants produced cyclic contractions using their soleus (which has a relatively homogeneous fibre type composition) at prescribed cycle-average ankle moments on a fixed dynamometer. Participants produced these ankle moments over short, medium and long durations while maintaining a constant cycle frequency. Overall, decreased duty factor did not affect cycle-average fascicle force (p ≥ 0.252) but did increase net metabolic power (p ≤ 0.022). Mechanistically, smaller duty factors increased maximum muscle-tendon force (p < 0.001), further stretching in-series tendons and shifting soleus fascicles to shorter lengths and faster velocities, thereby increasing soleus total active muscle volume (p < 0.001). Participant soleus total active muscle volume well-explained net metabolic power (r = 0.845; p < 0.001). Therefore, cyclically producing the same cycle-average muscle-tendon force using a decreased duty factor increases metabolic energy expenditure by eliciting less economical muscle contractile mechanics.


Assuntos
Metabolismo Energético/fisiologia , Músculo Esquelético/fisiologia , Tendões/fisiologia , Adulto , Tornozelo/fisiologia , Feminino , Marcha/fisiologia , Humanos , Masculino , Contração Muscular/fisiologia , Corrida/fisiologia , Caminhada/fisiologia
19.
Proc Biol Sci ; 287(1933): 20200995, 2020 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-32811317

RESUMO

Size and metabolism are highly correlated, so that community energy flux might be predicted from size distributions alone. However, the accuracy of predictions based on interspecific energy-size relationships relative to approaches not based on size distributions is unknown. We compare six approaches to predict energy flux in phytoplankton communities across succession: assuming a constant energy use among species (per cell or unit biomass), using energy-size interspecific scaling relationships and species-specific rates (both with or without accounting for density effects). Except for the per cell approach, all others explained some variation in energy flux but their accuracy varied considerably. Surprisingly, the best approach overall was based on mean biomass-specific rates, followed by the most complex (species-specific rates with density). We show that biomass-specific rates alone predict community energy flux because the allometric scaling of energy use with size measured for species in isolation does not reflect the isometric scaling of these species in communities. We also find energy equivalence throughout succession, even when communities are not at carrying capacity. Finally, we discuss that species assembly can alter energy-size relationships, and that metabolic suppression in response to density might drive the allometry of community energy flux as biomass accumulates.


Assuntos
Ecossistema , Fitoplâncton , Biomassa , Tamanho Corporal , Metabolismo Energético , Modelos Biológicos , Densidade Demográfica
20.
Yakugaku Zasshi ; 140(8): 963-968, 2020.
Artigo em Japonês | MEDLINE | ID: mdl-32741869

RESUMO

Metabolome analysis is an approach to investigate cell characteristics from the metabolites that are constantly produced and changed by those cells. We conducted a metabolome analysis of the response of 786-O renal cell carcinoma (RCC) cells to histone deacetylase (HDAC) inhibitors, which are expected to increase anticancer drug sensitivity, and compared the response with that of drug-resistant cells. Trichostatin A (TSA), an HDAC inhibitor, increased the sensitivity of 786-O cells to sunitinib. Moreover, TCA cycle and nucleotide metabolism of the cells were promoted. The findings that acetylated p53 (active form) and early apoptotic cells were increased suggests that the mechanism involved enhancement of mitochondrial metabolism and function. In addition, established sunitinib-resistant RCC cells were exposed to a combination of sunitinib and TSA, resulting in significant growth inhibition. Principal component analysis revealed that the parent and resistant cells were obviously different, but approximately half their fluctuations were illustrated by the same pathways. In summary, it was suggested that TSA reduced sunitinib resistance by triggering intracellular metabolome shifts in energy metabolism. This was the first recognized mechanism of action of TSA as an HDAC inhibitor.


Assuntos
Antineoplásicos/farmacologia , Carcinoma de Células Renais/metabolismo , Carcinoma de Células Renais/patologia , Inibidores de Histona Desacetilases/farmacologia , Ácidos Hidroxâmicos/farmacologia , Neoplasias Renais/metabolismo , Neoplasias Renais/patologia , Metaboloma , Metabolômica , Sunitinibe/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Humanos , Mitocôndrias/metabolismo , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/metabolismo
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