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1.
Nat Commun ; 11(1): 4940, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33009411

RESUMO

The HUSH complex represses retroviruses, transposons and genes to maintain the integrity of vertebrate genomes. HUSH regulates deposition of the epigenetic mark H3K9me3, but how its three core subunits - TASOR, MPP8 and Periphilin - contribute to assembly and targeting of the complex remains unknown. Here, we define the biochemical basis of HUSH assembly and find that its modular architecture resembles the yeast RNA-induced transcriptional silencing complex. TASOR, the central HUSH subunit, associates with RNA processing components. TASOR is required for H3K9me3 deposition over LINE-1 repeats and repetitive exons in transcribed genes. In the context of previous studies, this suggests that an RNA intermediate is important for HUSH activity. We dissect the TASOR and MPP8 domains necessary for transgene repression. Structure-function analyses reveal TASOR bears a catalytically-inactive PARP domain necessary for targeted H3K9me3 deposition. We conclude that TASOR is a multifunctional pseudo-PARP that directs HUSH assembly and epigenetic regulation of repetitive genomic targets.


Assuntos
Elementos de DNA Transponíveis/genética , Epigênese Genética , Complexos Multiproteicos/metabolismo , Proteínas Nucleares/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Sequência de Aminoácidos , Antígenos de Neoplasias/metabolismo , Sítios de Ligação , Éxons/genética , Genoma , Células HEK293 , Células HeLa , Histonas/metabolismo , Humanos , Lisina/metabolismo , Espectroscopia de Ressonância Magnética , Metilação , NAD/metabolismo , Proteínas Nucleares/química , Fosfoproteínas/metabolismo , Ligação Proteica , Domínios Proteicos , RNA/metabolismo , Processamento Pós-Transcricional do RNA , Transcrição Genética
3.
Anticancer Res ; 40(9): 4895-4905, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32878777

RESUMO

BACKGROUND/AIM: Nicotinamide phosphoribosyl-transferase (NAMPT) is a rate-limiting enzyme in the pathway synthesizing nicotinamide adenine dinucleotide (NAD (+)) from nicotinamide (NAM). Glioma tissues exhibit up-regulated NAMPT expression associated with a poor prognosis of patients. To determine if NAMPT can be a molecular therapeutic target, we investigated the effects of short hairpin RNA (shRNA)-mediated NAMPT down-regulation. MATERIALS AND METHODS: We designed shRNA to NAMPT and transfected to T98G cells. The characteristics of these cells were analyzed. RESULTS: The NAMPT shRNA-transfected cells exhibited delayed cell growth. However, there was no difference in the increase of sensitivity to temozolomide (TMZ) or X-ray irradiation between the NAMPT and scramble shRNA-transfected cells. The expression of NAMPT in the NAMPT shRNA-transfected cells increased with cell passage. Additionally, the shRNA-mediated transfection was associated with enhanced expression of quinolinic acid phosphoribo-syltransferase (QPRT). CONCLUSION: shRNA-mediated NAMPT down-regulation may not decrease the NADt to a sufficient level to increase TMZ/radiation sensitivity.


Assuntos
Citocinas/metabolismo , Regulação para Baixo , Glioma/enzimologia , Nicotinamida Fosforribosiltransferase/metabolismo , Antineoplásicos Alquilantes/farmacologia , Linhagem Celular Tumoral , Proliferação de Células , Citocinas/genética , Glioma/metabolismo , Glioma/patologia , Humanos , NAD/metabolismo , Nicotinamida Fosforribosiltransferase/genética , Pentosiltransferases/genética , Pentosiltransferases/metabolismo , RNA Interferente Pequeno/genética , Temozolomida/farmacologia
4.
Nature ; 585(7826): 609-613, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32939087

RESUMO

Breaks in DNA strands recruit the protein PARP1 and its paralogue PARP2 to modify histones and other substrates through the addition of mono- and poly(ADP-ribose) (PAR)1-5. In the DNA damage responses, this post-translational modification occurs predominantly on serine residues6-8 and requires HPF1, an accessory factor that switches the amino acid specificity of PARP1 and PARP2 from aspartate or glutamate to serine9,10. Poly(ADP) ribosylation (PARylation) is important for subsequent chromatin decompaction and provides an anchor for the recruitment of downstream signalling and repair factors to the sites of DNA breaks2,11. Here, to understand the molecular mechanism by which PARP enzymes recognize DNA breaks within chromatin, we determined the cryo-electron-microscopic structure of human PARP2-HPF1 bound to a nucleosome. This showed that PARP2-HPF1 bridges two nucleosomes, with the broken DNA aligned in a position suitable for ligation, revealing the initial step in the repair of double-strand DNA breaks. The bridging induces structural changes in PARP2 that signal the recognition of a DNA break to the catalytic domain, which licenses HPF1 binding and PARP2 activation. Our data suggest that active PARP2 cycles through different conformational states to exchange NAD+ and substrate, which may enable PARP enzymes to act processively while bound to chromatin. The processes of PARP activation and the PARP catalytic cycle we describe can explain mechanisms of resistance to PARP inhibitors and will aid the development of better inhibitors as cancer treatments12-16.


Assuntos
Proteínas de Transporte/metabolismo , Quebras de DNA de Cadeia Dupla , Proteínas Nucleares/metabolismo , Nucleossomos/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Biocatálise , Proteínas de Transporte/química , Proteínas de Transporte/ultraestrutura , Microscopia Crioeletrônica , DNA/metabolismo , Reparo do DNA , Ativação Enzimática , Humanos , Modelos Moleculares , NAD/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/ultraestrutura , Nucleossomos/química , Nucleossomos/ultraestrutura , Poli(ADP-Ribose) Polimerases/química , Poli(ADP-Ribose) Polimerases/ultraestrutura , Domínios Proteicos
5.
Nat Protoc ; 15(9): 2813-2836, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32747820

RESUMO

Several noncanonical initial nucleotides (NCINs) have been found to cap RNAs and possibly regulate RNA stability, transcription and translation. NAD+ is one of the NCINs that has recently been discovered to cap RNAs in a wide range of species. Identification of the NAD+-capped RNAs (NAD-RNAs) could help to unveil the cap-mediated regulation mechanisms. We previously reported a method termed NAD tagSeq for genome-wide analysis of NAD-RNAs. NAD tagSeq is based on the previously published NAD captureSeq protocol, which applies an enzymatic reaction and a click chemistry reaction to label NAD-RNAs with biotin followed by enrichment with streptavidin resin and identification by RNA sequencing. In the current NAD tagSeq method, NAD-RNAs are labeled with a synthetic RNA tag and identified by direct RNA sequencing based on Oxford Nanopore technology. Compared to NAD captureSeq, NAD tagSeq provides a simpler procedure for direct sequencing of NAD-RNAs and noncapped RNAs and affords information on the whole sequence organization of NAD-RNAs and the ratio of NAD-RNAs to total transcripts. Furthermore, NAD-RNAs can be enriched by hybridizing a complementary DNA probe to the RNA tag, thus increasing the sequencing coverage of NAD-RNAs. The strategy of tagging RNAs with a synthetic RNA tag and identifying them by direct RNA sequencing might be employed in analyzing other NCIN-capped RNAs. The experimental procedure of NAD tagSeq, including RNA extraction, RNA tagging and direct RNA sequencing, takes ~5 d, and initial data analysis can be completed within 2 d.


Assuntos
Perfilação da Expressão Gênica , NAD/metabolismo , Capuzes de RNA/genética , Capuzes de RNA/metabolismo , Análise de Sequência de RNA/métodos , Coloração e Rotulagem
6.
Life Sci ; 259: 118171, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32738362

RESUMO

Hypoxia, an important feature of the tumor microenvironment, is responsible for the chemo-resistance and metastasis of malignant solid tumors. Recent studies indicated that mitochondria undergo morphological transitions as an adaptive response to maintain self-stability and connectivity under hypoxic conditions. NAD+ may not only provide reducing equivalents for biosynthetic reactions and in determining energy production, but also functions as a signaling molecule in mitochondrial dynamics regulation. In this review, we describe the upregulated KDAC deacetylase expression in the mitochondria and cytoplasm of tumor cells that results from sensing the changes in NAD+ to control mitochondrial dynamics and distribution, which is responsible for survival and metastasis in hypoxia.


Assuntos
Hipóxia/metabolismo , Mitocôndrias/metabolismo , Dinâmica Mitocondrial , NAD/metabolismo , Metástase Neoplásica , Neoplasias/metabolismo , Animais , Resistencia a Medicamentos Antineoplásicos , Humanos , Microambiente Tumoral
7.
Nat Commun ; 11(1): 4135, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32811817

RESUMO

Complex I is the first and the largest enzyme of respiratory chains in bacteria and mitochondria. The mechanism which couples spatially separated transfer of electrons to proton translocation in complex I is not known. Here we report five crystal structures of T. thermophilus enzyme in complex with NADH or quinone-like compounds. We also determined cryo-EM structures of major and minor native states of the complex, differing in the position of the peripheral arm. Crystal structures show that binding of quinone-like compounds (but not of NADH) leads to a related global conformational change, accompanied by local re-arrangements propagating from the quinone site to the nearest proton channel. Normal mode and molecular dynamics analyses indicate that these are likely to represent the first steps in the proton translocation mechanism. Our results suggest that quinone binding and chemistry play a key role in the coupling mechanism of complex I.


Assuntos
Complexo I de Transporte de Elétrons/química , Simulação de Dinâmica Molecular , Quinonas/química , Thermus thermophilus/enzimologia , Regulação Alostérica , Proteínas de Bactérias/química , Microscopia Crioeletrônica , Cristalografia por Raios X , Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/metabolismo , Complexo I de Transporte de Elétrons/ultraestrutura , Modelos Moleculares , NAD/química , NAD/metabolismo , Redes Neurais de Computação , Conformação Proteica , Prótons , Quinonas/metabolismo , Thermus thermophilus/genética
8.
Viruses ; 12(8)2020 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-32722574

RESUMO

COVID-19 is a pandemic health emergency faced by the entire world. The clinical treatment of the severe acute respiratory syndrome (SARS) CoV-2 is currently based on the experimental administration of HIV antiviral drugs, such as lopinavir, ritonavir, and remdesivir (a nucleotide analogue used for Ebola infection). This work proposes a repurposing process using a database containing approximately 8000 known drugs in synergy structure- and ligand-based studies by means of the molecular docking and descriptor-based protocol. The proposed in silico findings identified new potential SARS CoV-2 main protease (MPRO) inhibitors that fit in the catalytic binding site of SARS CoV-2 MPRO. Several selected structures are NAD-like derivatives, suggesting a relevant role of these molecules in the modulation of SARS CoV-2 infection in conditions of cell chronic oxidative stress. Increased catabolism of NAD(H) during protein ribosylation in the DNA damage repair process may explain the greater susceptibility of the elderly population to the acute respiratory symptoms of COVID-19. The molecular modelling studies proposed herein agree with this hypothesis.


Assuntos
Antivirais/química , Antivirais/farmacologia , Betacoronavirus/efeitos dos fármacos , Betacoronavirus/enzimologia , Infecções por Coronavirus/tratamento farmacológico , Cisteína Endopeptidases/química , NAD/metabolismo , Pandemias , Pneumonia Viral/tratamento farmacológico , Inibidores de Proteases/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Proteínas não Estruturais Virais/química , Envelhecimento/metabolismo , Sítios de Ligação , Simulação por Computador , Infecções por Coronavirus/metabolismo , Infecções por Coronavirus/virologia , Dano ao DNA , Reposicionamento de Medicamentos , Inibidores da Protease de HIV/química , Inibidores da Protease de HIV/farmacologia , Humanos , Modelos Moleculares , Simulação de Acoplamento Molecular , Oxirredução , Pneumonia Viral/metabolismo , Pneumonia Viral/virologia , Inibidores de Proteases/química
9.
Nature ; 585(7824): 288-292, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32641834

RESUMO

The mitochondrial electron transport chain (ETC) is necessary for tumour growth1-6 and its inhibition has demonstrated anti-tumour efficacy in combination with targeted therapies7-9. Furthermore, human brain and lung tumours display robust glucose oxidation by mitochondria10,11. However, it is unclear why a functional ETC is necessary for tumour growth in vivo. ETC function is coupled to the generation of ATP-that is, oxidative phosphorylation and the production of metabolites by the tricarboxylic acid (TCA) cycle. Mitochondrial complexes I and II donate electrons to ubiquinone, resulting in the generation of ubiquinol and the regeneration of the NAD+ and FAD cofactors, and complex III oxidizes ubiquinol back to ubiquinone, which also serves as an electron acceptor for dihydroorotate dehydrogenase (DHODH)-an enzyme necessary for de novo pyrimidine synthesis. Here we show impaired tumour growth in cancer cells that lack mitochondrial complex III. This phenotype was rescued by ectopic expression of Ciona intestinalis alternative oxidase (AOX)12, which also oxidizes ubiquinol to ubiquinone. Loss of mitochondrial complex I, II or DHODH diminished the tumour growth of AOX-expressing cancer cells deficient in mitochondrial complex III, which highlights the necessity of ubiquinone as an electron acceptor for tumour growth. Cancer cells that lack mitochondrial complex III but can regenerate NAD+ by expression of the NADH oxidase from Lactobacillus brevis (LbNOX)13 targeted to the mitochondria or cytosol were still unable to grow tumours. This suggests that regeneration of NAD+ is not sufficient to drive tumour growth in vivo. Collectively, our findings indicate that tumour growth requires the ETC to oxidize ubiquinol, which is essential to drive the oxidative TCA cycle and DHODH activity.


Assuntos
Mitocôndrias/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , Ubiquinona/análogos & derivados , Animais , Linhagem Celular Tumoral , Proliferação de Células , Ciona intestinalis/enzimologia , Ciclo do Ácido Cítrico , Citosol/metabolismo , Transporte de Elétrons , Complexo I de Transporte de Elétrons/metabolismo , Complexo II de Transporte de Elétrons/metabolismo , Complexo III da Cadeia de Transporte de Elétrons/deficiência , Complexo III da Cadeia de Transporte de Elétrons/metabolismo , Humanos , Lactobacillus brevis/enzimologia , Masculino , Camundongos , Mitocôndrias/enzimologia , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Complexos Multienzimáticos/genética , Complexos Multienzimáticos/metabolismo , NAD/metabolismo , NADH NADPH Oxirredutases/genética , NADH NADPH Oxirredutases/metabolismo , Neoplasias/enzimologia , Fosforilação Oxidativa , Oxirredutases/genética , Oxirredutases/metabolismo , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ubiquinona/metabolismo
10.
Nat Commun ; 11(1): 3427, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32647171

RESUMO

The contribution of inflammation to the chronic joint disease osteoarthritis (OA) is unclear, and this lack of clarity is detrimental to efforts to identify therapeutic targets. Here we show that chondrocytes under inflammatory conditions undergo a metabolic shift that is regulated by NF-κB activation, leading to reprogramming of cell metabolism towards glycolysis and lactate dehydrogenase A (LDHA). Inflammation and metabolism can reciprocally modulate each other to regulate cartilage degradation. LDHA binds to NADH and promotes reactive oxygen species (ROS) to induce catabolic changes through stabilization of IκB-ζ, a critical pro-inflammatory mediator in chondrocytes. IκB-ζ is regulated bi-modally at the stages of transcription and protein degradation. Overall, this work highlights the function of NF-κB activity in the OA joint as well as a ROS promoting function for LDHA and identifies LDHA as a potential therapeutic target for OA treatment.


Assuntos
Condrócitos/metabolismo , Lactato Desidrogenase 5/metabolismo , Terapia de Alvo Molecular , Osteoartrite/tratamento farmacológico , Espécies Reativas de Oxigênio/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Aerobiose , Animais , Cartilagem Articular/patologia , Células Cultivadas , Condrócitos/efeitos dos fármacos , Condrócitos/patologia , Citoproteção/efeitos dos fármacos , Deleção de Genes , Regulação da Expressão Gênica/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Humanos , Inflamação/metabolismo , Inflamação/patologia , Interleucina-1beta/farmacologia , Articulação do Joelho/patologia , Meniscos Tibiais/cirurgia , Redes e Vias Metabólicas/efeitos dos fármacos , Camundongos Endogâmicos C57BL , NAD/metabolismo , NF-kappa B/metabolismo , Osteoartrite/genética , Osteoartrite/patologia
11.
Nat Commun ; 11(1): 3238, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32591540

RESUMO

The challenge of monitoring in planta dynamic changes of NADP(H) and NAD(H) redox states at the subcellular level is considered a major obstacle in plant bioenergetics studies. Here, we introduced two circularly permuted yellow fluorescent protein sensors, iNAP and SoNar, into Arabidopsis thaliana to monitor the dynamic changes in NADPH and the NADH/NAD+ ratio. In the light, photosynthesis and photorespiration are linked to the redox states of NAD(P)H and NAD(P) pools in several subcellular compartments connected by the malate-OAA shuttles. We show that the photosynthetic increases in stromal NADPH and NADH/NAD+ ratio, but not ATP, disappear when glycine decarboxylation is inhibited. These observations highlight the complex interplay between chloroplasts and mitochondria during photosynthesis and support the suggestions that, under normal conditions, photorespiration supplies a large amount of NADH to mitochondria, exceeding its NADH-dissipating capacity, and the surplus NADH is exported from the mitochondria to the cytosol through the malate-OAA shuttle.


Assuntos
Arabidopsis/fisiologia , Arabidopsis/efeitos da radiação , Luz , Proteínas Luminescentes/metabolismo , NADP/metabolismo , NAD/metabolismo , Fotossíntese/efeitos da radiação , Respiração Celular/efeitos da radiação , Cloroplastos/metabolismo , Citosol/metabolismo , Transporte de Elétrons/efeitos da radiação , Malatos/metabolismo , Mitocôndrias/metabolismo , Modelos Biológicos , Oxirredução , Peroxissomos/metabolismo , Plântula/metabolismo , Plântula/efeitos da radiação
12.
J Infect Public Health ; 13(9): 1196-1201, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32534944

RESUMO

The aging-associated decline of biological functions represents an important contributor to the increase in morbidity and mortality of human beings. Of these biological functions deterioration; there is a significant decline in the heart function, impairments in the lungs gas exchange, and impairments in the immune function. Many alterations in the body humeral and cellular immune response were observed with ageing process: The circulating pro-inflammatory cytokines are increased, the naive lymphocytes are decreased, the numbers of the antigen-presenting cells areelevated and the overall response is impaired. In addition, ageing is associated with a progressive restriction in the telomere length. Telomeres are located at chromosomes ends and play an essential role in preserving chromosome stability. Also, telomere length is very important to the immune system, because of the high sensitivity of the immune cells to the shortening of telomeres. Telomeres shortening adversely affect the immune cells' function and developments. These adverse changes increased the susceptibility for severe infection, risk of hospitalization, and even death. Elderly COVID-19 patients are at a real risk of complications due to impaired immune function, cytokine storm and defective respiratory function. Administration of anti-ageing immunomodulation factors like Nicotinamide Adenine Dinucleotide NAD+ can minimize these changes through its potent immunomodulation and longevity effects. NAD+ has a direct inhibitory effect on PARP-1 and can prevent pro-inflammatory cytokines over-activation. Increasing the NAD+ level will also result in stabilizing telomeres and this has a positive impact on immune cells function.


Assuntos
Envelhecimento/imunologia , Infecções por Coronavirus/imunologia , NAD/imunologia , NAD/metabolismo , Pneumonia Viral/imunologia , Encurtamento do Telômero/imunologia , Doenças Autoimunes/imunologia , Betacoronavirus , Infecções por Coronavirus/tratamento farmacológico , Citocinas/imunologia , Humanos , NAD/uso terapêutico , Pandemias , Pneumonia Viral/tratamento farmacológico , Poli(ADP-Ribose) Polimerase-1/antagonistas & inibidores
13.
Mol Cell ; 78(5): 805-807, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32502419

RESUMO

The amplitude of circadian rhythms dampens with age, but Levine et al. (2020) now show that nicotinamide adenine dinucleotide (NAD+) can restore robust circadian gene expression and behavior in aged mice through SIRT1-dependent deacetylation of the core clock protein PER2.


Assuntos
Ritmo Circadiano/genética , Proteínas Circadianas Period/metabolismo , Fatores de Transcrição ARNTL/genética , Fatores Etários , Animais , Relógios Circadianos/fisiologia , Ritmo Circadiano/fisiologia , Citocinas/metabolismo , Humanos , Camundongos , NAD/metabolismo , Proteínas Circadianas Period/genética , Sirtuína 1/metabolismo , Sirtuínas/metabolismo
14.
Sheng Wu Gong Cheng Xue Bao ; 36(5): 992-1001, 2020 May 25.
Artigo em Chinês | MEDLINE | ID: mdl-32567282

RESUMO

In this study, Escherichia coli BL21 (DE3) was used as the host to construct 2 recombinant E. coli strains that co-expressed leucine dehydrogenase (LDH, Bacillus cereus)/formate dehydrogenase (FDH, Ancylobacter aquaticus), or leucine dehydrogenase (LDH, Bacillus cereus)/alcohol dehydrogenase (ADH, Rhodococcus), respectively. L-2-aminobutyric acid was then synthesized by L-threonine deaminase (L-TD) with LDH-FDH or LDH-ADH by coupling with two different NADH regeneration systems. LDH-FDH process and LDH-ADH process were optimized and compared with each other. The optimum reaction pH of LDH-FDH process was 7.5, and the optimum reaction temperature was 35 °C. After 28 h, the concentration of L-2-aminobutyric acid was 161.8 g/L with a yield of 97%, when adding L-threonine in batches for controlling 2-ketobutyric acid concentration less than 15 g/L and using 50 g/L ammonium formate, 0.3 g/L NAD+, 10% LDH-FDH crude enzyme solution (V/V) and 7 500 U/L L-TD. The optimum reaction pH of LDH-ADH process was 8.0, and the optimum reaction temperature was 35 °C. After 24 h, the concentration of L-2-aminobutyric acid was 119.6 g/L with a yield of 98%, when adding L-threonine and isopropanol (1.2 times of L-threonine) in batches for controlling 2-ketobutyric acid concentration less than 15 g/L, removing acetone in time and using 0.3 g/L NAD⁺, 10% LDH-ADH crude enzyme solution (V/V) and 7 500 U/L L-TD. The process and results used in this paper provide a reference for the industrialization of L-2-aminobutyric acid.


Assuntos
Aminobutiratos , Leucina Desidrogenase , NAD , Aminobutiratos/metabolismo , Escherichia coli/genética , Formiato Desidrogenases/metabolismo , Leucina Desidrogenase/metabolismo , NAD/metabolismo
15.
Nat Commun ; 11(1): 2790, 2020 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-32493904

RESUMO

Age-dependent changes in metabolism can manifest as cellular lipid accumulation, but how this accumulation is regulated or impacts longevity is poorly understood. We find that Saccharomyces cerevisiae accumulate lipid droplets (LDs) during aging. We also find that over-expressing BNA2, the first Biosynthesis of NAD+ (kynurenine) pathway gene, reduces LD accumulation during aging and extends lifespan. Mechanistically, this LD accumulation during aging is not linked to NAD+ levels, but is anti-correlated with metabolites of the shikimate and aromatic amino acid biosynthesis (SA) pathways (upstream of BNA2), which produce tryptophan (the Bna2p substrate). We provide evidence that over-expressed BNA2 skews glycolytic flux from LDs towards the SA-BNA pathways, effectively reducing LDs. Importantly, we find that accumulation of LDs does not shorten lifespan, but does protect aged cells against stress. Our findings reveal how lipid accumulation impacts longevity, and how aging cell metabolism can be rewired to modulate lipid accumulation independently from longevity.


Assuntos
Metabolismo dos Lipídeos , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Vias Biossintéticas , Temperatura Baixa , Gotículas Lipídicas/metabolismo , Metaboloma , NAD/metabolismo , Saccharomyces cerevisiae/citologia , Proteínas de Saccharomyces cerevisiae/metabolismo , Ácido Chiquímico/metabolismo , Estresse Fisiológico
16.
Nat Commun ; 11(1): 2816, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32499527

RESUMO

The intense arms race between bacteria and phages has led to the development of diverse antiphage defense systems in bacteria. Unlike well-known restriction-modification and CRISPR-Cas systems, recently discovered systems are poorly characterized. One such system is the Thoeris defense system, which consists of two genes, thsA and thsB. Here, we report structural and functional analyses of ThsA and ThsB. ThsA exhibits robust NAD+ cleavage activity and a two-domain architecture containing sirtuin-like and SLOG-like domains. Mutation analysis suggests that NAD+ cleavage is linked to the antiphage function of Thoeris. ThsB exhibits a structural resemblance to TIR domain proteins such as nucleotide hydrolases and Toll-like receptors, but no enzymatic activity is detected in our in vitro assays. These results further our understanding of the molecular mechanism underlying the Thoeris defense system, highlighting a unique strategy for bacterial antiphage resistance via NAD+ degradation.


Assuntos
Bacteriófagos/genética , Escherichia coli/virologia , NAD/metabolismo , Bacillus cereus/metabolismo , Sistemas CRISPR-Cas , Clonagem Molecular , Cristalografia por Raios X , Análise Mutacional de DNA , Escherichia coli/metabolismo , Hidrolases/metabolismo , Cinética , Mutação , Domínios Proteicos , Estrutura Secundária de Proteína , Receptores Toll-Like/metabolismo
17.
Nat Commun ; 11(1): 2600, 2020 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-32451409

RESUMO

Light-dependent or light-stimulated catalysis provides a multitude of perspectives for implementation in technological or biomedical applications. Despite substantial progress made in the field of photobiocatalysis, the number of usable light-responsive enzymes is still very limited. Flavoproteins have exceptional potential for photocatalytic applications because the name-giving cofactor intrinsically features light-dependent reactivity, undergoing photoreduction with a variety of organic electron donors. However, in the vast majority of these enzymes, photoreactivity of the enzyme-bound flavin is limited or even suppressed. Here, we present a flavoprotein monooxygenase in which catalytic activity is controllable by blue light illumination. The reaction depends on the presence of nicotinamide nucleotide-type electron donors, which do not support the reaction in the absence of light. Employing various experimental approaches, we demonstrate that catalysis depends on a protein-mediated photoreduction of the flavin cofactor, which proceeds via a radical mechanism and a transient semiquinone intermediate.


Assuntos
Proteínas de Bactérias/metabolismo , Transporte de Elétrons , Flavina-Adenina Dinucleotídeo/metabolismo , Oxigenases de Função Mista/metabolismo , NAD/metabolismo , Pseudomonas aeruginosa/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Biocatálise , Cristalografia por Raios X , Flavoproteínas Transferidoras de Elétrons/química , Flavoproteínas Transferidoras de Elétrons/genética , Flavoproteínas Transferidoras de Elétrons/metabolismo , Luz , Oxigenases de Função Mista/química , Oxigenases de Função Mista/genética , Modelos Moleculares , NADP/metabolismo , Oxirredução , Processos Fotoquímicos , Pseudomonas aeruginosa/genética
18.
Nature ; 583(7814): 122-126, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32461692

RESUMO

The cellular NADH/NAD+ ratio is fundamental to biochemistry, but the extent to which it reflects versus drives metabolic physiology in vivo is poorly understood. Here we report the in vivo application of Lactobacillus brevis (Lb)NOX1, a bacterial water-forming NADH oxidase, to assess the metabolic consequences of directly lowering the hepatic cytosolic NADH/NAD+ ratio in mice. By combining this genetic tool with metabolomics, we identify circulating α-hydroxybutyrate levels as a robust marker of an elevated hepatic cytosolic NADH/NAD+ ratio, also known as reductive stress. In humans, elevations in circulating α-hydroxybutyrate levels have previously been associated with impaired glucose tolerance2, insulin resistance3 and mitochondrial disease4, and are associated with a common genetic variant in GCKR5, which has previously been associated with many seemingly disparate metabolic traits. Using LbNOX, we demonstrate that NADH reductive stress mediates the effects of GCKR variation on many metabolic traits, including circulating triglyceride levels, glucose tolerance and FGF21 levels. Our work identifies an elevated hepatic NADH/NAD+ ratio as a latent metabolic parameter that is shaped by human genetic variation and contributes causally to key metabolic traits and diseases. Moreover, it underscores the utility of genetic tools such as LbNOX to empower studies of 'causal metabolism'.


Assuntos
Fígado/metabolismo , NAD/metabolismo , Estresse Fisiológico , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Citosol/metabolismo , Modelos Animais de Doenças , Fatores de Crescimento de Fibroblastos/sangue , Variação Genética , Teste de Tolerância a Glucose , Humanos , Resistência à Insulina , Lactobacillus brevis/enzimologia , Lactobacillus brevis/genética , Masculino , Camundongos , Complexos Multienzimáticos/genética , Complexos Multienzimáticos/metabolismo , NADH NADPH Oxirredutases/genética , NADH NADPH Oxirredutases/metabolismo , Oxirredução , Triglicerídeos/sangue
19.
Mol Cell ; 78(5): 835-849.e7, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32369735

RESUMO

Disrupted sleep-wake and molecular circadian rhythms are a feature of aging associated with metabolic disease and reduced levels of NAD+, yet whether changes in nucleotide metabolism control circadian behavioral and genomic rhythms remains unknown. Here, we reveal that supplementation with the NAD+ precursor nicotinamide riboside (NR) markedly reprograms metabolic and stress-response pathways that decline with aging through inhibition of the clock repressor PER2. NR enhances BMAL1 chromatin binding genome-wide through PER2K680 deacetylation, which in turn primes PER2 phosphorylation within a domain that controls nuclear transport and stability and that is mutated in human advanced sleep phase syndrome. In old mice, dampened BMAL1 chromatin binding, transcriptional oscillations, mitochondrial respiration rhythms, and late evening activity are restored by NAD+ repletion to youthful levels with NR. These results reveal effects of NAD+ on metabolism and the circadian system with aging through the spatiotemporal control of the molecular clock.


Assuntos
Relógios Circadianos/fisiologia , Ritmo Circadiano/genética , Proteínas Circadianas Period/metabolismo , Fatores de Transcrição ARNTL/genética , Fatores Etários , Envelhecimento/genética , Animais , Proteínas CLOCK/genética , Ritmo Circadiano/fisiologia , Citocinas/metabolismo , Feminino , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NAD/metabolismo , Proteínas Circadianas Period/genética , Sirtuína 1/metabolismo , Sirtuínas/metabolismo
20.
Nucleic Acids Res ; 48(11): 6136-6148, 2020 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-32374864

RESUMO

In eukaryotes, the DXO/Rai1 enzymes can eliminate most of the incomplete and non-canonical NAD caps through their decapping, deNADding and pyrophosphohydrolase activities. Here, we report that these enzymes can also remove FAD and dephospho-CoA (dpCoA) non-canonical caps from RNA, and we have named these activities deFADding and deCoAping. The crystal structures of mammalian DXO with 3'-FADP or CoA and fission yeast Rai1 with 3'-FADP provide elegant insight to these activities. FAD and CoA are accommodated in the DXO/Rai1 active site by adopting folded conformations. The flavin of FAD and the pantetheine group of CoA contact the same region at the bottom of the active site tunnel, which undergoes conformational changes to accommodate the different cap moieties. We have developed FAD-capQ to detect and quantify FAD-capped RNAs and determined that FAD caps are present on short RNAs (with less than ∼200 nucleotides) in human cells and that these RNAs are stabilized in the absence of DXO.


Assuntos
Coenzima A/metabolismo , Exorribonucleases/metabolismo , Flavina-Adenina Dinucleotídeo/metabolismo , Kluyveromyces/enzimologia , Capuzes de RNA/metabolismo , RNA Mensageiro/química , RNA Mensageiro/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Animais , Flavina-Adenina Dinucleotídeo/análise , Células HEK293 , Humanos , Técnicas In Vitro , Camundongos , Modelos Moleculares , NAD/metabolismo , Capuzes de RNA/análise , Especificidade por Substrato , Transcrição Genética
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