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1.
New Phytol ; 225(3): 1047-1048, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31894589
2.
Nat Commun ; 11(1): 586, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31996681

RESUMO

The endothelial to haematopoietic transition (EHT) is the process whereby haemogenic endothelium differentiates into haematopoietic stem and progenitor cells (HSPCs). The intermediary steps of this process are unclear, in particular the identity of endothelial cells that give rise to HSPCs is unknown. Using single-cell transcriptome analysis and antibody screening, we identify CD44 as a marker of EHT enabling us to isolate robustly the different stages of EHT in the aorta-gonad-mesonephros (AGM) region. This allows us to provide a detailed phenotypical and transcriptional profile of CD44-positive arterial endothelial cells from which HSPCs emerge. They are characterized with high expression of genes related to Notch signalling, TGFbeta/BMP antagonists, a downregulation of genes related to glycolysis and the TCA cycle, and a lower rate of cell cycle. Moreover, we demonstrate that by inhibiting the interaction between CD44 and its ligand hyaluronan, we can block EHT, identifying an additional regulator of HSPC development.


Assuntos
Biomarcadores , Endotélio/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Receptores de Hialuronatos/metabolismo , Transcriptoma , Animais , Aorta , Artérias , Ciclo Celular , Ciclo do Ácido Cítrico/genética , Biologia Computacional , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Regulação para Baixo , Glicólise/genética , Gônadas , Hematopoese/fisiologia , Receptores de Hialuronatos/sangue , Receptores de Hialuronatos/genética , Ácido Hialurônico , Mesonefro , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator de Crescimento Transformador beta/metabolismo
3.
Exp Parasitol ; 208: 107792, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31707003

RESUMO

Nitazoxanide (NTZ) is a broad-spectrum drug used in intestinal infections, but still poorly explored in the treatment of parasitic tissular infections. This study aimed to evaluate the in vitro responses of the energetic metabolism of T. crassiceps cysticerci induced by NTZ. The organic acids of the tricarboxylic acid cycle, products derived from fatty acids oxidation and protein catabolism were analyzed. These acids were quantified after 24 h of in vitro exposure to different NTZ concentrations. A positive control group was performed with albendazole sulfoxide (ABZSO). The significant alterations in citrate, fumarate and malate concentrations showed the NTZ influence in the tricarboxylic acid (TCA) cycle. The non-detection of acetate confirmed that the main mode of action of NTZ is effective against T. crassiceps cysticerci. The statistical differences in fumarate, urea and beta-hydroxybutyrate concentrations showed the NTZ effect on protein catabolism and fatty acid oxidation. Therefore, the main energetic pathways such as the TCA cycle, protein catabolism and fatty acids oxidation were altered after in vitro NTZ exposure. In conclusion, NTZ induced a significant metabolic stress in the parasite indicating that it may be used as an alternative therapeutic choice for cysticercosis treatment. The use of metabolic approaches to establish comparisons between anti parasitic drugs mode of actions is proposed.


Assuntos
Antiparasitários/farmacologia , Taenia/efeitos dos fármacos , Tiazóis/farmacologia , Albendazol/análogos & derivados , Albendazol/farmacologia , Análise de Variância , Animais , Anti-Helmínticos/farmacologia , Citratos/metabolismo , Ciclo do Ácido Cítrico/efeitos dos fármacos , Meios de Cultura/química , Cysticercus/efeitos dos fármacos , Cysticercus/metabolismo , Metabolismo Energético/efeitos dos fármacos , Fumaratos/metabolismo , Ácidos Cetoglutáricos/metabolismo , Malatos/metabolismo , Neurocisticercose/tratamento farmacológico , Ácido Oxaloacético/metabolismo , Ácido Succínico/metabolismo , Taenia/metabolismo
4.
Biochim Biophys Acta Bioenerg ; 1861(2): 148137, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31825809

RESUMO

Electron transfer from all respiratory chain dehydrogenases of the electron transport chain (ETC) converges at the level of the quinone (Q) pool. The Q redox state is thus a function of electron input (reduction) and output (oxidation) and closely reflects the mitochondrial respiratory state. Disruption of electron flux at the level of the cytochrome bc1 complex (cIII) or cytochrome c oxidase (cIV) shifts the Q redox poise to a more reduced state which is generally sensed as respiratory stress. To cope with respiratory stress, many species, but not insects and vertebrates, express alternative oxidase (AOX) which acts as an electron sink for reduced Q and by-passes cIII and cIV. Here, we used Ciona intestinalis AOX xenotopically expressed in mouse mitochondria to study how respiratory states impact the Q poise and how AOX may be used to restore respiration. Particularly interesting is our finding that electron input through succinate dehydrogenase (cII), but not NADH:ubiquinone oxidoreductase (cI), reduces the Q pool almost entirely (>90%) irrespective of the respiratory state. AOX enhances the forward electron transport (FET) from cII thereby decreasing reverse electron transport (RET) and ROS specifically when non-phosphorylating. AOX is not engaged with cI substrates, however, unless a respiratory inhibitor is added. This sheds new light on Q poise signaling, the biological role of cII which enigmatically is the only ETC complex absent from respiratory supercomplexes but yet participates in the tricarboxylic acid (TCA) cycle. Finally, we delineate potential risks and benefits arising from therapeutic AOX transfer.


Assuntos
Aldeído Oxidase/metabolismo , Ciona intestinalis/genética , Expressão Gênica , Mitocôndrias Cardíacas/enzimologia , Espécies Reativas de Oxigênio/metabolismo , Aldeído Oxidase/genética , Animais , Ciclo do Ácido Cítrico/genética , Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/metabolismo , Camundongos , Mitocôndrias Cardíacas/genética , Consumo de Oxigênio/genética , Succinato Desidrogenase/genética , Succinato Desidrogenase/metabolismo
5.
Food Chem ; 308: 125621, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31644969

RESUMO

Yellowing of rice during storage is a highly concerned issue for managing rice quality whereas the yellowing mechanism is not clearly elucidated so far. Thus, the comparative untargeted metabolomic analysis was performed in this study. The results revealed that glycolysis pathway and tricarboxylic acid cycle (TCA) were significantly enhanced in yellowed rice, indicating the activated energy metabolism was trigged during the yellowing process. In addition, the increased aromatic compounds (4-hydroxycinnamic acid and benzoic acid) and their precursors (phenylalanine, tyrosine) suggested the activation of shikimate-phenylpropanoid biosynthesis in yellowed rice, which is an antioxidant defense related pathway. In particular, the pathways involved in the metabolism of glutamate and arginine also significantly altered in yellowed rice. Therefore, the enriched pathways of increased amino acids, sugars, sugar alcohols, and intermediates of the TCA cycle during yellowing process are proposed to be associated with the response of heat and dry induced by the yellowing process.


Assuntos
Oryza/metabolismo , Antioxidantes/metabolismo , Ciclo do Ácido Cítrico , Cor , Metabolômica
6.
Food Chem ; 305: 125439, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31499287

RESUMO

Compared to the control longans, hydrogen peroxide (H2O2)-treated longans exhibited higher index of pulp breakdown, higher fruit respiration rate, higher activities of pulp phosphohexose isomerase (PGI), succinate dehydrogenase (SDH), cytochrome C oxidase (CCO), ascorbic acid oxidase (AAO) and polyphenol oxidase (PPO), but lower activity of pulp nicotinamide adenine dinucleotide kinase (NADK). H2O2-treated longans also exhibited lower total activities of pulp glucose-6-phosphate dehydrogenase (G-6-PDH) and 6-phosphogluconate dehydrogenase (6-PGDH), lower levels of pulp NADP(H), but higher levels of pulp NAD(H). These data indicated that H2O2-stimulated longan pulp breakdown was owing to a decreased proportion of pentose phosphate pathway (PPP), the increased proportions of Embden-Meyerhof-Parnas pathway (EMP), tricarboxylic acid (TCA) cycle and cytochrome pathway (CCP) in total respiratory pathways. These findings further revealed that H2O2 could enhance respiration rate, and thus accelerate pulp breakdown occurrence and shorten the shelf life of longan fruit.


Assuntos
Peróxido de Hidrogênio/farmacologia , Sapindaceae/efeitos dos fármacos , Aldeído Oxidase/metabolismo , Ciclo do Ácido Cítrico/efeitos dos fármacos , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Armazenamento de Alimentos , Frutas/metabolismo , Glucosefosfato Desidrogenase/metabolismo , Glicólise/efeitos dos fármacos , NAD/metabolismo , Via de Pentose Fosfato/efeitos dos fármacos , Sapindaceae/metabolismo
7.
Int. microbiol ; 22(4): 461-470, dic. 2019. graf, tab
Artigo em Inglês | IBECS | ID: ibc-185064

RESUMO

To date, tripartite tricarboxylate transport (TTT) systems are not well characterized in most organisms. To investigate which carbon sources are transported by the TTT system of A. mimigardefordensis DPN7T, single deletion mutants were generated lacking either completely both sets of genes encoding for these transport systems tctABCDE1 and tctABDE2 in the organism or the two genes encoding for the regulatory components of the third chosen TTT system, tctDE3. Deletion of tctABCDE1 (MIM_c39170-MIM_c39210) in Advenella mimigardefordensis strain DPN7T led to inhibition of growth of the cells with citrate indicating that TctABCDE1 is the transport system for the uptake of citrate. Because of the negative phenotype, it was concluded that this deletion cannot be substituted by other transporters encoded in the genome of strain DPN7T. A triple deletion mutant of A. mimigardefordensis lacking both complete TTT transport systems and the regulatory components of the third chosen system (ΔTctABCDE1 ΔTctABDE2 ΔTctDE3) showed a leaky growth with alpha-ketoglutarate in comparison with the wild type. The other investigated TTT (TctABDE3, MIM_c17190-MIM_c17220) is most probably involved in the transport of alpha-ketoglutarate. Additionally, thermoshift assays with TctC1 (MIM_c39190) showed a significant shift in the melting temperature of the protein in the presence of citrate whereas no shift occurred with alpha-ketoglutarate. A dissociation constant Kd for citrate of 41.7 μM was determined. Furthermore, alternative alpha-ketoglutarate transport was investigated via in silico analysis


No disponible


Assuntos
Ácidos Tricarboxílicos/metabolismo , Bordetella/genética , Betaproteobacteria/enzimologia , Propionatos/metabolismo , Succinato-CoA Ligases/metabolismo , Transportadores de Ácidos Dicarboxílicos/genética , Ácidos Dicarboxílicos/metabolismo , Espectrometria de Massas/métodos , Ciclo do Ácido Cítrico , Betaproteobacteria/classificação , Propionatos/química , Succinato-CoA Ligases/genética
8.
Immunity ; 51(6): 997-1011.e7, 2019 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-31851905

RESUMO

Toll-like receptor (TLR) activation induces inflammatory responses in macrophages by activating temporally defined transcriptional cascades. Whether concurrent changes in the cellular metabolism that occur upon TLR activation influence the quality of the transcriptional responses remains unknown. Here, we investigated how macrophages adopt their metabolism early after activation to regulate TLR-inducible gene induction. Shortly after TLR4 activation, macrophages increased glycolysis and tricarboxylic acid (TCA) cycle volume. Metabolic tracing studies revealed that TLR signaling redirected metabolic fluxes to generate acetyl-Coenzyme A (CoA) from glucose resulting in augmented histone acetylation. Signaling through the adaptor proteins MyD88 and TRIF resulted in activation of ATP-citrate lyase, which in turn facilitated the induction of distinct LPS-inducible gene sets. We postulate that metabolic licensing of histone acetylation provides another layer of control that serves to fine-tune transcriptional responses downstream of TLR activation. Our work highlights the potential of targeting the metabolic-epigenetic axis in inflammatory settings.


Assuntos
ATP Citrato (pro-S)-Liase/metabolismo , Acetilcoenzima A/metabolismo , Histonas/metabolismo , Macrófagos/metabolismo , Receptor 4 Toll-Like/metabolismo , Acetilação , Proteínas Adaptadoras de Transporte Vesicular/genética , Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Animais , Ciclo do Ácido Cítrico/fisiologia , Glicólise/fisiologia , Humanos , Lipopolissacarídeos/metabolismo , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/metabolismo , Transdução de Sinais , Transcrição Genética/genética
9.
BMC Plant Biol ; 19(1): 592, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31881988

RESUMO

BACKGROUND: The tricarboxylic acid (TCA) cycle is crucial for cellular energy metabolism and carbon skeleton supply. However, the detailed functions of the maize TCA cycle genes remain unclear. RESULTS: In this study, 91 TCA genes were identified in maize by a homology search, and they were distributed on 10 chromosomes and 1 contig. Phylogenetic results showed that almost all maize TCA genes could be classified into eight major clades according to their enzyme families. Sequence alignment revealed that several genes in the same subunit shared high protein sequence similarity. The results of cis-acting element analysis suggested that several TCA genes might be involved in signal transduction and plant growth. Expression profile analysis showed that many maize TCA cycle genes were expressed in specific tissues, and replicate genes always shared similar expression patterns. Moreover, qPCR analysis revealed that some TCA genes were highly expressed in the anthers at the microspore meiosis phase. In addition, we predicted the potential interaction networks among the maize TCA genes. Next, we cloned five TCA genes located on different TCA enzyme complexes, Zm00001d008244 (isocitrate dehydrogenase, IDH), Zm00001d017258 (succinyl-CoA synthetase, SCoAL), Zm00001d025258 (α-ketoglutarate dehydrogenase, αKGDH), Zm00001d027558 (aconitase, ACO) and Zm00001d044042 (malate dehydrogenase, MDH). Confocal observation showed that their protein products were mainly localized to the mitochondria; however, Zm00001d025258 and Zm00001d027558 were also distributed in the nucleus, and Zm00001d017258 and Zm00001d044042 were also located in other unknown positions in the cytoplasm. Through the bimolecular fluorescent complimentary (BiFC) method, it was determined that Zm00001d027558 and Zm00001d044042 could form homologous dimers, and both homologous dimers were mainly distributed in the mitochondria. However, no heterodimers were detected between these five genes. Finally, Arabidopsis lines overexpressing the above five genes were constructed, and those transgenic lines exhibited altered primary root length, salt tolerance, and fertility. CONCLUSION: Sequence compositions, duplication patterns, phylogenetic relationships, cis-elements, expression patterns, and interaction networks were investigated for all maize TCA cycle genes. Five maize TCA genes were overexpressed in Arabidopsis, and they could alter primary root length, salt tolerance, and fertility. In conclusion, our findings may help to reveal the molecular function of the TCA genes in maize.


Assuntos
Ciclo do Ácido Cítrico/genética , Genes de Plantas , Zea mays/genética , Sequência de Aminoácidos , Arabidopsis/genética , Biologia Computacional , Lycopersicon esculentum/genética , Filogenia , Proteínas de Plantas/genética , Alinhamento de Sequência , Transcriptoma , Zea mays/metabolismo
10.
Metabolism ; 101: 153993, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31672442

RESUMO

BACKGROUND: Therapies targeting altered activity of pyruvate dehydrogenase (PDH) and pyruvate carboxylase (PC) have been proposed for hepatomas. However, the activities of these pathways in hepatomas in vivo have not been distinguished. Here we examined pyruvate entry into the tricarboxylic acid (TCA) cycle through PDH versus PC in vivo using hepatoma-bearing rats. METHODS: Hepatoma-bearing rats were generated by intrahepatic injection of H4IIE cells. Metabolism of 13C-labeled glycerol, a physiological substrate for both gluconeogenesis and energy production, was measured with 13C NMR analysis. The concentration of key metabolites and the expression of relevant enzymes were measured in hepatoma, surrounding liver, and normal liver. RESULTS: In orthotopic hepatomas, pyruvate entry into the TCA cycle occurred exclusively through PDH and the excess PDH activity compared to normal liver was attributed to downregulated pyruvate dehydrogenase kinase (PDK) 2/4. However, pyruvate carboxylation via PC and gluconeogenesis were minimal, which was linked to downregulated forkhead box O1 (FoxO1) by Akt activity. In contrast to many studies of cancer metabolism, lactate production in hepatomas was not increased which corresponded to reduced expression of lactate dehydrogenase. The production of serine and glycine in hepatomas was enhanced, but glycine decarboxylase was downregulated. CONCLUSIONS: The combination of [U-13C3]glycerol and NMR analysis enabled investigation of multiple biochemical processes in hepatomas and surrounding liver. We demonstrated active PDH and other related metabolic alterations in orthotopic hepatomas that differed substantially not only from the host organ but also from many earlier studies with cancer cells.


Assuntos
Carcinoma Hepatocelular/metabolismo , Gluconeogênese , Neoplasias Hepáticas/metabolismo , Complexo Piruvato Desidrogenase/metabolismo , Animais , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13/métodos , Carcinoma Hepatocelular/enzimologia , Ciclo do Ácido Cítrico , Glicerol/metabolismo , Fígado/enzimologia , Neoplasias Hepáticas/enzimologia , Ratos
11.
Nat Ecol Evol ; 3(12): 1715-1724, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31712697

RESUMO

It has been suggested that a deep memory of early life is hidden in the architecture of metabolic networks, whose reactions could have been catalyzed by small molecules or minerals before genetically encoded enzymes. A major challenge in unravelling these early steps is assessing the plausibility of a connected, thermodynamically consistent proto-metabolism under different geochemical conditions, which are still surrounded by high uncertainty. Here we combine network-based algorithms with physico-chemical constraints on chemical reaction networks to systematically show how different combinations of parameters (temperature, pH, redox potential and availability of molecular precursors) could have affected the evolution of a proto-metabolism. Our analysis of possible trajectories indicates that a subset of boundary conditions converges to an organo-sulfur-based proto-metabolic network fuelled by a thioester- and redox-driven variant of the reductive tricarboxylic acid cycle that is capable of producing lipids and keto acids. Surprisingly, environmental sources of fixed nitrogen and low-potential electron donors are not necessary for the earliest phases of biochemical evolution. We use one of these networks to build a steady-state dynamical metabolic model of a protocell, and find that different combinations of carbon sources and electron donors can support the continuous production of a minimal ancient 'biomass' composed of putative early biopolymers and fatty acids.


Assuntos
Ciclo do Ácido Cítrico , Redes e Vias Metabólicas , Biomassa , Carbono , Enxofre
12.
Elife ; 82019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31610847

RESUMO

Alzheimer's disease (AD) is the most common neurodegenerative disease affecting the elderly worldwide. Mitochondrial dysfunction has been proposed as a key event in the etiology of AD. We have previously modeled amyloid-beta (Aß)-induced mitochondrial dysfunction in a transgenic Caenorhabditis elegans strain by expressing human Aß peptide specifically in neurons (GRU102). Here, we focus on the deeper metabolic changes associated with this Aß-induced mitochondrial dysfunction. Integrating metabolomics, transcriptomics and computational modeling, we identify alterations in Tricarboxylic Acid (TCA) cycle metabolism following even low-level Aß expression. In particular, GRU102 showed reduced activity of a rate-limiting TCA cycle enzyme, alpha-ketoglutarate dehydrogenase. These defects were associated with elevation of protein carbonyl content specifically in mitochondria. Importantly, metabolic failure occurred before any significant increase in global protein aggregate was detectable. Treatment with an anti-diabetes drug, Metformin, reversed Aß-induced metabolic defects, reduced protein aggregation and normalized lifespan of GRU102. Our results point to metabolic dysfunction as an early and causative event in Aß-induced pathology and a promising target for intervention.


Assuntos
Peptídeos beta-Amiloides/genética , Caenorhabditis elegans/metabolismo , Ciclo do Ácido Cítrico/genética , Mitocôndrias/metabolismo , Neurônios/metabolismo , Estresse Fisiológico/genética , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/genética , Ciclo do Ácido Cítrico/efeitos dos fármacos , Modelos Animais de Doenças , Humanos , Hipoglicemiantes/farmacologia , Complexo Cetoglutarato Desidrogenase/genética , Complexo Cetoglutarato Desidrogenase/metabolismo , Análise do Fluxo Metabólico , Metformina/farmacologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Neurônios/efeitos dos fármacos , Neurônios/patologia , Agregados Proteicos/efeitos dos fármacos , Carbonilação Proteica , Estresse Fisiológico/efeitos dos fármacos
13.
Se Pu ; 37(8): 887-896, 2019 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-31642260

RESUMO

Speckle type BTB/POZ protein (SPOP) is one of the most frequently mutated protein in prostate cancer. In this study, proteomics and metabolomics were integrated to study the effects of SPOP mutation on metabolism. First, LNCaP control (CON), SPOP wild-type (SPOP_WT), and SPOP mutation (SPOP_Y87N and SPOP_F133L) cells were subjected to a metabolomics study. The metabolomics data of LNCaP CON, SPOP_WT, SPOP_Y87N, and SPOP_F133L cells were evaluated by partial least squares-discriminant analysis (PLS-DA). Four groups could be clearly differentiated with an explanation ability of R2X=0.512, R2Y=0.616 and predictive ability of Q2=0.475. Totally, 36 differential metabolites were defined with variable importance for the projection (VIP) value > 1. Then, the 36 metabolites were subjected to one-way ANOVA analysis. Fumaric acid, malic acid, citric acid, aspartic acid, and asparagine were increased in LNCaP SPOP mutation cells compared to that in LNCaP SPOP_WT cells. Using a proteomics study, 909 differential proteins were found in LNCaP SPOP_Y87N and SPOP_F133L cells. MetaboAnalyst 3.0 was used to enrich metabolic pathways by using differential metabolites. KOBAS 3.0 was used to enrich metabolic pathways by using differential proteins. Both metabolomics and proteomics analysis showed that the tricarboxylic acid (TCA) cycle and aminoacyl-tRNA biosynthesis were significantly changed. To validate these findings, gas chromatography-mass spectrometry (GC-MS)-based metabolomics was performed in Du145 SPOP knock-out cells. The results indicated that the TCA cycle was activated in Du145 SPOP knock-out cells. Collectively, this study found that SPOP mutation significantly promoted TCA cycle in prostate cancer cells.


Assuntos
Domínio BTB-POZ , Metabolômica , Proteínas Nucleares/genética , Neoplasias da Próstata/genética , Proteômica , Proteínas Repressoras/genética , Linhagem Celular Tumoral , Ciclo do Ácido Cítrico , Humanos , Masculino , Redes e Vias Metabólicas , Mutação
14.
Nat Commun ; 10(1): 4639, 2019 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-31604954

RESUMO

Isocitrate lyase is important for lipid utilisation by Mycobacterium tuberculosis but its ICL2 isoform is poorly understood. Here we report that binding of the lipid metabolites acetyl-CoA or propionyl-CoA to ICL2 induces a striking structural rearrangement, substantially increasing isocitrate lyase and methylisocitrate lyase activities. Thus, ICL2 plays a pivotal role regulating carbon flux between the tricarboxylic acid (TCA) cycle, glyoxylate shunt and methylcitrate cycle at high lipid concentrations, a mechanism essential for bacterial growth and virulence.


Assuntos
Acetilcoenzima A/metabolismo , Isocitrato Liase/metabolismo , Mycobacterium tuberculosis/enzimologia , Acetilcoenzima A/fisiologia , Acil Coenzima A/metabolismo , Carbono/metabolismo , Ciclo do Ácido Cítrico , Cristalografia por Raios X , Isocitrato Liase/química , Metabolismo dos Lipídeos , Espectroscopia de Ressonância Magnética , Simulação de Acoplamento Molecular , Domínios Proteicos
15.
Life Sci ; 239: 116966, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31626790

RESUMO

AIMS: Enhanced aerobic glycolysis is an essential hallmark of malignant cancer. Blocking the glycolytic pathway has been suggested as a therapeutic strategy to impair the proliferation of tumor cells. Metformin, a widely used anti-diabetes drug, exhibits anti-tumor properties. However, the underlying molecular mechanism of its action linking glucose metabolism with the suppression of proliferation has not been fully clarified. MAIN METHODS: Stable isotope tracing technology and gas chromatography-mass spectrometry method were utilized to analyze the effect of metformin on glycolytic flux in HCC cells. Western blot and immunohistochemistry were utilized to analyze the expression of phosphofructokinase-1 (PFK1) and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) in HCC cells or xenograft tumor tissues. Lactate measurement and glucose uptake assay were used to analyze the level of lactate and glucose in the presence of frucose-2,6-diphosphate (F2,6BP) in HCC cells treated with metformin. KEY FINDINGS: We found that metformin significantly impaired hepatoma cell proliferation by inhibiting the glycolytic flux via PFK1 blockade. Interestingly, activation of PFK1 by F2,6BP reverses the inhibitory effect of metformin on hepatoma cell proliferation and glycolysis. Mechanistically, PFKFB3,a potent allosteric activator of PFK1, was markedly suppressed through inhibiting hypoxia-induced factor 1 (HIF-1α) accumulation mediated by metformin. SIGNIFICANCE: Taken together these data indicate that HIF-1α/PFKFB3/PFK1 regulatory axis is a vital determinant of glucose metabolic reprogramming in hepatocellular carcinoma, which gives new insights into the action of metformin in combatting liver cancer.


Assuntos
Carcinoma Hepatocelular/tratamento farmacológico , Glicólise/efeitos dos fármacos , Metformina/farmacologia , Animais , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ciclo do Ácido Cítrico , Glucose/metabolismo , Células Hep G2 , Humanos , Hipoglicemiantes , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Masculino , Metformina/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Fosfofrutoquinase-1/metabolismo , Fosfofrutoquinase-2/metabolismo , Fosforilação , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
16.
Plant Physiol Biochem ; 143: 265-274, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31525604

RESUMO

Horticulture nitrogen (N) runoffs are major environmental and health concerns, but current farming practices cannot detect ineffective N applications. Hence, we set to recognize high N conditions and characterize their effects on the physiology of almond trees grown in drainage lysimeters. Water and nutrients mass balances exhibited that N benefitted almond trees in a limited range (below 60 mg N L-1 in irrigation), while higher N conditions (over a 100 mg N L-1) reduced evapotranspiration (ET) by 50% and inherently constrained N uptake. Respectively, whole-tree hydraulic conductance reduced by 37%, and photosynthesis by 17%, which implied that high N concentrations could damage trees. Through gas-chromatography, we realized that high N conditions also affected components of the citric acid cycle (TCA) and carbohydrates availability. Such changes in the metabolic composition of roots and leaves probably interfered with N assimilation and respiration. It also determined the proportions between N and starch in almond leaves, which formed a new index (N:ST) that starts at 0.4 in N deficiency and reaches 0.6-0.8 in optimal N conditions. Importantly, this index continues to increase in higher N conditions (as starch reduces) and essentially indicates to excessive N applications when it exceeds 1.1.


Assuntos
Prunus dulcis/metabolismo , Ciclo do Ácido Cítrico/genética , Ciclo do Ácido Cítrico/fisiologia , Fotossíntese/genética , Fotossíntese/fisiologia , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Transpiração Vegetal/fisiologia , Prunus dulcis/fisiologia
17.
Chemosphere ; 236: 124420, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31545208

RESUMO

The combined effects of exposure to increasing temperature and copper (Cu) concentrations were evaluated in the zooxanthellate scleractinian coral Mussismilia harttii. Endpoints analyzed included activity of enzymes involved in glycolysis (pyruvate kinase, PK; lactate dehydrogenase, LDH), Krebs cycle (citrate synthase, CS; isocitrate dehydrogenase; IDH), electron transport chain (electron transport system, ETS) and pentose phosphate pathway (glucose-6-phosphate dehydrogenase, G6PDH). Coral polyps were kept under control conditions (25.0 ±â€¯0.1 °C; 2.9 ±â€¯0.7 µg/L Cu) or exposed to combined treatments of increasing temperature (26.6 ±â€¯0.1 °C and 27.3 ±â€¯0.1 °C) and concentrations of dissolved Cu (5.4 ±â€¯0.9 and 8.6 ±â€¯0.3 µg/L) for 4 and 12 days using a mesocosm system. PK activity was not affected by stressors. LDH, CS, IDH, ETS and G6PDH activities were temporally inhibited by stressors alone. CS, ETS and G6PDH activities remained inhibited by the combination of stressors after 12 days. Furthermore, all combinations between increasing temperature and exposure Cu were synergistic after prolonged exposure. Taken together, stressors applied alone led to temporary inhibitory effects on energy metabolism enzymes of the coral M. harttii, however, prolonged exposure reveals strong deleterious effects over the metabolism of corals due to the combination of stressors. The present study is the first one to give insights into the combined effects of increasing temperature and Cu exposure in the energy metabolism enzymes of a scleractinian coral. Findings suggest that moderate Cu contamination in future increasing temperature scenarios can be worrying for aerobic and oxidative metabolism of M. harttii.


Assuntos
Antozoários/enzimologia , Cobre/farmacologia , Metabolismo Energético , Temperatura Ambiente , Animais , Antozoários/efeitos dos fármacos , Ciclo do Ácido Cítrico , Glicólise , L-Lactato Desidrogenase/metabolismo , Via de Pentose Fosfato , Poluentes Químicos da Água/farmacologia
18.
Bioresour Technol ; 292: 121949, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31398545

RESUMO

The aims of this study are to reveal the roles of tricarboxylic acid (TCA) cycle regulators in reducing CO2 emission and promoting humic substance (HS) formation during composting with different materials. The results showed that the addition of adenosine tri-phosphate (ATP) or malonic acid (MA) reduced CO2 emission during chicken manure composting. However, only the addition of MA reduced CO2 emission during lawn waste and garden waste composting. In addition, both of the two inhibitors promoted HS formation, especially for ATP. Structural equation models further confirmed that ATP and MA reduced CO2 emission by inhibiting the decomposition of amino acid by microorganisms. Meanwhile, ATP promoted the conversion of amino acid and soluble sugars to HS, while MA only promoted the conversion of soluble sugars to HS. In summary, this study provides a theoretical basis for the application of inhibitors to reduce CO2 emission and promote HS formation during composting.


Assuntos
Compostagem , Animais , Ciclo do Ácido Cítrico , Substâncias Húmicas , Esterco , Solo
19.
Oncogene ; 38(44): 6970-6984, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31409901

RESUMO

Clinical applications of antiangiogenic agents profoundly affect tumor cell behaviors via the resultant hypoxia. To date, how the hypoxia regulates tumor cells remains unclear. Here, we show that hypoxia promotes the growth of human breast tumorigenic cells that repopulate tumors [tumor-repopulating cells (TRCs)] in vitro and in vivo. This stimulating effect is ascribed to hypoxia-induced reactive oxygen species (ROS) that activates Akt and NF-κB, dependent on the attenuated tricarboxylic acid (TCA) cycle. We find that fumarate is accumulated in the TCA cycle of hypoxic TRCs, leading to glutathione succination, NADPH/NADP+ decrease, and an increase in ROS levels. Mechanistically, hypoxia-increased HIF-1α transcriptionally downregulates the expression of mitochondrial phosphoenolpyruvate carboxykinase (PCK2), leading to TCA cycle attenuation and fumarate accumulation. These findings reveal that hypoxia-reprogrammed TCA cycle promotes human breast TRCs growth via a HIF-1α-downregulated PCK2 pathway, implying a need for a combination of an antiangiogenic therapy with an antioxidant modulator.


Assuntos
Neoplasias da Mama/patologia , Hipóxia Celular/fisiologia , Ciclo do Ácido Cítrico/fisiologia , Neoplasias da Mama/metabolismo , Regulação para Baixo , Feminino , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Células-Tronco Neoplásicas/metabolismo , Fosfoenolpiruvato Carboxiquinase (ATP)/metabolismo , Microambiente Tumoral
20.
Pharm Pat Anal ; 8(4): 117-138, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31414969

RESUMO

Cancer metabolism is currently a hot topic. Since it was first realized that cancer cells rely upon an altered metabolic program to sustain their rapid proliferation, the enzymes that support those metabolic changes have appeared to be good targets for pharmacological intervention. Here, we discuss efforts pertaining to targets in cancer metabolism, focusing upon the tricarboxylic acid cycle and the mechanisms which feed nutrients into it. We describe a broad landscape of small-molecule inhibitors, targeting a dozen different proteins, each implicated in cancer progression. We hope that this will serve as a reference both to the areas being most highly examined today and, relatedly, the areas that are still ripe for novel intervention.


Assuntos
Neoplasias/metabolismo , Animais , Ciclo do Ácido Cítrico , Glicólise , Humanos , Patentes como Assunto
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