Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27.241
Filtrar
1.
Physiol Rev ; 102(1): 339-341, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-34494892

RESUMO

During the COVID-19 pandemic, efforts have been made worldwide to develop effective therapies to address the devastating immune-mediated effects of SARS-CoV-2. With the exception of monoclonal antibody-mediated therapeutics and preventive approaches such as mass immunization, most experimental or repurposed drugs have failed in large randomized clinical trials (https://www.who.int/publications/i/item/therapeutics-and-covid-19-living-guideline). The worldwide spread of SARS-CoV-2 virus revealed specific susceptibilities to the virus among the elderly and individuals with age-related syndromes. These populations were more likely to experience a hyperimmune response characterized by a treatment-resistant acute lung pathology accompanied by multiple organ failure. These observations underscore the interplay between the virus, the biology of aging, and outcomes observed in the most severe cases of SARS-CoV-2 infection. The ectoenzyme CD38 has been implicated in the process of "inflammaging" in aged tissues. In a current publication, Horenstein et al. present evidence to support the hypothesis that CD38 plays a central role in altered immunometabolism resulting from COVID-19 infection. The authors discuss a critical but underappreciated trifecta of CD38-mediated NAD+ metabolism, aging, and COVID-19 immune response and speculate that the CD38/NAD+ axis is a promising therapeutic target for this disease.


Assuntos
ADP-Ribosil Ciclase 1/metabolismo , COVID-19/fisiopatologia , Glicoproteínas de Membrana/metabolismo , SARS-CoV-2 , ADP-Ribosil Ciclase 1/genética , Envelhecimento , Regulação Enzimológica da Expressão Gênica , Humanos , Glicoproteínas de Membrana/genética , NAD/metabolismo
2.
Extremophiles ; 25(5-6): 513-526, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34647163

RESUMO

Thermoanaerobacter kivui is an acetogenic model organism that reduces CO2 with electrons derived from H2 or CO, or from organic substrates in the Wood-Ljugdahl pathway (WLP). For the calculation of ATP yields, it is necessary to know the electron carriers involved in coupling of the oxidative and reductive parts of metabolism. Analyses of key catabolic oxidoreductases in cell-free extract (CFE) or with purified enzymes revealed the physiological electron carriers involved. The glyceraldehyde-3-phosphate dehydrogenase (GA3P-DH) assayed in CFE was NAD+-specific, NADP+ was used with less than 4% and ferredoxin (Fd) was not used. The methylene-THF dehydrogenase was NADP+-specific, NAD+ or Fd were not used. A Nfn-type transhydrogenase that catalyzes reduced Fd-dependent reduction of NADP+ with NADH as electron donor was also identified in CFE. The electron carriers used by the potential electron-bifurcating hydrogenase (HydABC) could not be unambiguously determined in CFE for technical reasons. Therefore, the enzyme was produced homologously in T. kivui and purified by affinity chromatography. HydABC contained 33.9 ± 4.5 mol Fe/mol of protein and FMN; it reduced NADP+ but not NAD+. The methylene-THF reductase (MetFV) was also produced homologously in T. kivui and purified by affinity chromatography. MetFV contained 7.2 ± 0.4 mol Fe/mol of protein and FMN; the complex did neither use NADPH nor NADH as reductant but only reduced Fd. In sum, these analysis allowed us to propose a scheme for entire electron flow and bioenergetics in T. kivui.


Assuntos
Elétrons , Hidrogenase , Processos Autotróficos , Hidrogenase/metabolismo , NAD/metabolismo , NADP , Oxirredução , Thermoanaerobacter/metabolismo
3.
J Biomed Opt ; 26(10)2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34628733

RESUMO

SIGNIFICANCE: Deranged metabolism and dysregulated growth factor signaling are closely associated with abnormal levels of proliferation, a recognized hallmark in tumorigenesis. Fluorescence lifetime imaging microscopy (FLIM) of endogenous nicotinamide adenine dinucleotide (NADH), a key metabolic coenzyme, offers a non-invasive, diagnostic indicator of disease progression, and treatment response. The model-independent phasor analysis approach leverages FLIM to rapidly evaluate cancer metabolism in response to targeted therapy. AIM: We combined lifetime and phasor FLIM analysis to evaluate the influence of human epidermal growth factor receptor 2 (HER2) inhibition, a prevalent cancer biomarker, on both nuclear and cytoplasmic NAD(P)H of two squamous cell carcinoma (SCC) cultures. While better established, the standard lifetime analysis approach is relatively slow and potentially subject to intrinsic fitting errors and model assumptions. Phasor FLIM analysis offers a rapid, model-independent alternative, but the sensitivity of the bound NAD(P)H fraction to growth factor signaling must also be firmly established. APPROACH: Two SCC cultures with low- and high-HER2 expression, were imaged using multiphoton-excited NAD(P)H FLIM, with and without treatment of the HER2 inhibitor AG825. Cells were challenged with mitochondrial inhibition and uncoupling to investigate AG825's impact on the overall metabolic capacity. Phasor FLIM and lifetime fitting analyses were compared within nuclear and cytoplasmic compartments to investigate epigenetic and metabolic impacts of HER2 inhibition. RESULTS: NAD(P)H fluorescence lifetime and bound fraction consistently decreased following HER2 inhibition in both cell lines. High-HER2 SCC74B cells displayed a more significant response than low-HER2 SCC74A in both techniques. HER2 inhibition induced greater changes in nuclear than cytoplasmic compartments, leading to an increase in NAD(P)H intensity and concentration. CONCLUSIONS: The use of both, complementary FLIM analysis techniques together with quantitative fluorescence intensity revealed consistent, quantitative changes in NAD(P)H metabolism associated with inhibition of growth factor signaling in SCC cell lines. HER2 inhibition promoted increased reliance on oxidative phosphorylation in both cell lines.


Assuntos
Carcinoma de Células Escamosas , NAD , Carcinoma de Células Escamosas/diagnóstico por imagem , Carcinoma de Células Escamosas/tratamento farmacológico , Epigênese Genética , Humanos , Microscopia de Fluorescência , NAD/metabolismo , Receptor ErbB-2
4.
Int J Mol Sci ; 22(19)2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34638936

RESUMO

Nicotinamide adenine dinucleotide (NAD+) and its reduced form (NADH) are coenzymes employed in hundreds of metabolic reactions. NAD+ also serves as a substrate for enzymes such as sirtuins, poly(ADP-ribose) polymerases (PARPs) and ADP-ribosyl cyclases. Given the pivotal role of NAD(H) in health and disease, studying NAD+ metabolism has become essential to monitor genetic- and/or drug-induced perturbations related to metabolic status and diseases (such as ageing, cancer or obesity), and its possible therapies. Here, we present a strategy based on liquid chromatography-tandem mass spectrometry (LC-MS/MS), for the analysis of the NAD+ metabolome in biological samples. In this method, hydrophilic interaction chromatography (HILIC) was used to separate a total of 18 metabolites belonging to pathways leading to NAD+ biosynthesis, including precursors, intermediates and catabolites. As redox cofactors are known for their instability, a sample preparation procedure was developed to handle a variety of biological matrices: cell models, rodent tissues and biofluids, as well as human biofluids (urine, plasma, serum, whole blood). For clinical applications, quantitative LC-MS/MS for a subset of metabolites was demonstrated for the analysis of the human whole blood of nine volunteers. Using this developed workflow, our methodology allows studying NAD+ biology from mechanistic to clinical applications.


Assuntos
Metaboloma , NAD/biossíntese , Plasma/metabolismo , Soro/metabolismo , Espectrometria de Massas em Tandem/métodos , Urina/fisiologia , Animais , Doadores de Sangue , Cromatografia Líquida/métodos , Células Hep G2 , Humanos , Interações Hidrofóbicas e Hidrofílicas , Metabolômica/métodos , Camundongos , Camundongos Endogâmicos C57BL , Monitorização Fisiológica/métodos , Oxirredução , Projetos Piloto , Plasma/química , Soro/química , Urina/química
5.
Nature ; 598(7880): 364-367, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34616041

RESUMO

The enzymes of the mitochondrial electron transport chain are key players of cell metabolism. Despite being active when isolated, in vivo they associate into supercomplexes1, whose precise role is debated. Supercomplexes CIII2CIV1-2 (refs. 2,3), CICIII2 (ref. 4) and CICIII2CIV (respirasome)5-10 exist in mammals, but in contrast to CICIII2 and the respirasome, to date the only known eukaryotic structures of CIII2CIV1-2 come from Saccharomyces cerevisiae11,12 and plants13, which have different organization. Here we present the first, to our knowledge, structures of mammalian (mouse and ovine) CIII2CIV and its assembly intermediates, in different conformations. We describe the assembly of CIII2CIV from the CIII2 precursor to the final CIII2CIV conformation, driven by the insertion of the N terminus of the assembly factor SCAF1 (ref. 14) deep into CIII2, while its C terminus is integrated into CIV. Our structures (which include CICIII2 and the respirasome) also confirm that SCAF1 is exclusively required for the assembly of CIII2CIV and has no role in the assembly of the respirasome. We show that CIII2 is asymmetric due to the presence of only one copy of subunit 9, which straddles both monomers and prevents the attachment of a second copy of SCAF1 to CIII2, explaining the presence of one copy of CIV in CIII2CIV in mammals. Finally, we show that CIII2 and CIV gain catalytic advantage when assembled into the supercomplex and propose a role for CIII2CIV in fine tuning the efficiency of electron transfer in the electron transport chain.


Assuntos
Respiração Celular , Mitocôndrias/enzimologia , Complexos Multienzimáticos/química , Complexos Multienzimáticos/metabolismo , Ovinos , Animais , Sítios de Ligação , Conjuntos de Dados como Assunto , Transporte de Elétrons , Camundongos , Mitocôndrias/metabolismo , Modelos Moleculares , NAD/metabolismo , Ácido Succínico/metabolismo
6.
Nanoscale ; 13(36): 15188-15192, 2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34553737

RESUMO

In a typical colloidal synthesis, the molecules of the reducing agent are irreversibly oxidized during nanocrystal growth. Such a scenario is of questionable sustainability when confronted with naturally occurring processes in which reducing agent molecules are cyclically regenerated. Here we show that cofactor molecules once consumed in the nucleation and growth of metallic nanocrystals can be photoregenerated using metallic nanocrystals as photocatalysts and reused in the subsequent nucleation process. Cyclic regeneration of cofactor molecules opens up the possibilities for the sustainable synthesis of inorganic nanoparticles.


Assuntos
Nanopartículas Metálicas , NAD , Catálise , Oxirredução , Regeneração
7.
BMC Res Notes ; 14(1): 372, 2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34556160

RESUMO

OBJECTIVE: The objective of this study was to investigate the variation of NAD and CoA metabolite pools in Saccharomyces cerevisiae cultivated under various cultivation conditions. This study complements a previous report on glycolytic, pentose phosphate pathway, tricarboxylic acid cycle, amino acids, and deoxy-/nucleoside phosphate pools determined under the same cultivation conditions. RESULTS: S. cerevisiae pellets from batch (four carbohydrate sources) and chemostat (carbon-, nitrogen-, phosphate-limited and a range of dilution rates) bioreactor cultivations were extracted and analyzed with two recently established absolute quantitative liquid chromatography mass spectrometry (LC-MS/MS) methods for NAD and CoA metabolites. Both methods apply 13C internal standard dilution strategy for the enhanced analytical accuracy and precision. Individual metabolite pools were relatively constant for the different growth rates within the same mode of cultivation, but large differences were observed among some of the modes, i.e. NAD metabolites were 10 to 100-fold lower in nitrogen limited chemostats compared to the other modes, and phosphate limited chemostats were characterized with much lower CoA metabolite pools. The results complement the previous results and together provide a comprehensive insight into primary metabolite pools variations at a large range in growth and carbon source consumption rates.


Assuntos
NAD , Saccharomyces cerevisiae , Cromatografia Líquida , Coenzima A , Espectrometria de Massas em Tandem
8.
Talanta ; 235: 122730, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517598

RESUMO

The enzyme sorbitol dehydrogenase (SDH) is an emerging biomarker of drug-induced liver injury (DILI). This paper introduces determination of SDH in microliter samples of human serum at commercial glucose test strips. The determination relies on the oxidation of NADH cofactor, which is used by SDH reacting with its substrates. The strips could detect NADH down to 5.0 µM (5 pmol), which was two orders of magnitude better than the prior relevant limit of detection. The concentration of cofactors (NADH, NAD+) and substrates (fructose, sorbitol) for SDH determination at a strip was optimized via internally-calibrated amperometric assays at a chitosan/nitrogen-doped carbon nanotube electrode. Such an electrode provided reliable assay data for over 3 months with no need for its reactivation. The assays yielded kinetic parameters Km and kcat and demonstrated higher apparent affinity of SDH for NADH and fructose than NAD+ and sorbitol. The glucose strips detected SDH down to 98 pM (98 amol) in buffers and 200 pM (200 amol) in human serum after 20-min incubation with an optimized (c ≥ 10Km) mixture of cofactor + substrate. The charge ΔQ flowing through a strip was linear (R2, 0.994) up to 6.0 nM SDH, which covered enzyme's clinical range. The ΔQ was selective for SDH, independent of sample matrix, and free of interferences from indigenous glucose. The use of glucose strip as an electrolytic microcell to detect picomoles of NADH and attomoles of SDH is a step toward a point-of-care monitoring of DILI.


Assuntos
L-Iditol 2-Desidrogenase , Sorbitol , Frutose , Glucose , Humanos , Cinética , L-Iditol 2-Desidrogenase/metabolismo , NAD
9.
Zhongguo Zhong Yao Za Zhi ; 46(16): 4034-4039, 2021 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-34467712

RESUMO

As anti-aging ingredients, ß-nicotinamide mononucleotide(NMN) and nicotinamide adenine dinucleotide(NAD~+) have attracted worldwide attention in recent years. After oral administration, NMN can be converted into NAD~+ in vivo and the latter is the actual ingredient which exerts anti-aging effect. In order to explore the "rejuvenating and anti-aging" effect of Dendrobium officinale, which was firstly recorded in Shennong's Herbal Classic of Materia Medica, this study established the quantitative method of UPLC-MS/MS for simultaneous determination of NMN and NAD~+ in D. officinale and the congeneric species for the first time, and 34 batches of samples were detected. UPLC conditions are as follows: ACQUITY UPLC HSS T3 column(2.1 mm × 100 mm, 1.8 µm), gradient elution with acetonitrile-0.1% formic acid in water at the flow rate of 0.3 mL·min~(-1), and column temperature of 40 ℃. MS conditions were scanned electrospray ionization source and multiple reaction monitoring mode. The method was verified by systematic methodology. The mean recoveries of NMN and NAD~+ were 77.58% and 80.70%, respectively, with RSD of 3.6% and 4.3%, separately. All results showed that the content of NMN was higher in D. officinale than in the other congeneric species. Particularly, the content in fresh D. officinale stems was as high as 0.931 9 µg·g~(-1). NAD~+ was only found in D. officinale and the content was three times higher than that of NMN. This may be the reason that D. officinale topped the "nine famous anti-aging herbs". In addition, processing method influences the content of NMN and NAD~+ in Dendrobium. Specifically, the content of NMN and NAD~+ was in the order of fresh Dendrobium stems > dried Dendrobium stem segments > spiral or spring-like dried Dendrobium stems.


Assuntos
Dendrobium , Mononucleotídeo de Nicotinamida , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , NAD , Espectrometria de Massas em Tandem
10.
Mol Cell ; 81(18): 3848-3865.e19, 2021 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-34547241

RESUMO

Metabolic rewiring and redox balance play pivotal roles in cancer. Cellular senescence is a barrier for tumorigenesis circumvented in cancer cells by poorly understood mechanisms. We report a multi-enzymatic complex that reprograms NAD metabolism by transferring reducing equivalents from NADH to NADP+. This hydride transfer complex (HTC) is assembled by malate dehydrogenase 1, malic enzyme 1, and cytosolic pyruvate carboxylase. HTC is found in phase-separated bodies in the cytosol of cancer or hypoxic cells and can be assembled in vitro with recombinant proteins. HTC is repressed in senescent cells but induced by p53 inactivation. HTC enzymes are highly expressed in mouse and human prostate cancer models, and their inactivation triggers senescence. Exogenous expression of HTC is sufficient to bypass senescence, rescue cells from complex I inhibitors, and cooperate with oncogenic RAS to transform primary cells. Altogether, we provide evidence for a new multi-enzymatic complex that reprograms metabolism and overcomes cellular senescence.


Assuntos
Senescência Celular/fisiologia , NAD/metabolismo , Envelhecimento/metabolismo , Envelhecimento/fisiologia , Animais , Linhagem Celular Tumoral , Senescência Celular/genética , Citosol , Glucose/metabolismo , Humanos , Hidrogênio/química , Hidrogênio/metabolismo , Malato Desidrogenase/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos Transgênicos , NAD/fisiologia , Oxirredução , Piruvato Carboxilase/metabolismo , Ácido Pirúvico/metabolismo
11.
J Exp Biol ; 224(18)2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34495320

RESUMO

Endurance exercise is an important way to resist and treat high-fat diet (HFD)-induced lipotoxic cardiomyopathy, but the underlying molecular mechanisms are poorly understood. Here, we used Drosophila to identify whether cardiac Nmnat/NAD+/SIR2 pathway activation mediates endurance exercise-induced resistance to lipotoxic cardiomyopathy. The results showed that endurance exercise activated the cardiac Nmnat/NAD+/SIR2/FOXO pathway and the Nmnat/NAD+/SIR2/PGC-1α pathway, including up-regulating cardiac Nmnat, SIR2, FOXO and PGC-1α expression, superoxide dismutase (SOD) activity and NAD+ levels, and it prevented HFD-induced or cardiac Nmnat knockdown-induced cardiac lipid accumulation, malondialdehyde (MDA) content and fibrillation increase, and fractional shortening decrease. Cardiac Nmnat overexpression also activated heart Nmnat/NAD+/SIR2 pathways and resisted HFD-induced cardiac malfunction, but it could not protect against HFD-induced lifespan reduction and locomotor impairment. Exercise improved lifespan and mobility in cardiac Nmnat knockdown flies. Therefore, the current results confirm that cardiac Nmnat/NAD+/SIR2 pathways are important antagonists of HFD-induced lipotoxic cardiomyopathy. Cardiac Nmnat/NAD+/SIR2 pathway activation is an important underlying molecular mechanism by which endurance exercise and cardiac Nmnat overexpression give protection against lipotoxic cardiomyopathy in Drosophila.


Assuntos
Cardiomiopatias , Proteínas de Drosophila , Envelhecimento , Animais , Cardiomiopatias/genética , Drosophila , Proteínas de Drosophila/genética , NAD
12.
Cells ; 10(9)2021 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-34571983

RESUMO

The metabolic milieu of solid tumors provides a barrier to chimeric antigen receptor (CAR) T-cell therapies. Excessive lactate or hypoxia suppresses T-cell growth, through mechanisms including NADH buildup and the depletion of oxidized metabolites. NADH is converted into NAD+ by the enzyme Lactobacillus brevis NADH Oxidase (LbNOX), which mimics the oxidative function of the electron transport chain without generating ATP. Here we determine if LbNOX promotes human CAR T-cell metabolic activity and antitumor efficacy. CAR T-cells expressing LbNOX have enhanced oxygen as well as lactate consumption and increased pyruvate production. LbNOX renders CAR T-cells resilient to lactate dehydrogenase inhibition. But in vivo in a model of mesothelioma, CAR T-cell's expressing LbNOX showed no increased antitumor efficacy over control CAR T-cells. We hypothesize that T cells in hostile environments face dual metabolic stressors of excessive NADH and insufficient ATP production. Accordingly, futile T-cell NADH oxidation by LbNOX is insufficient to promote tumor clearance.


Assuntos
Trifosfato de Adenosina/metabolismo , Complexos Multienzimáticos/metabolismo , NADH NADPH Oxirredutases/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Adulto , Animais , Feminino , Humanos , Lactobacillus brevis/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , NAD/metabolismo , Oxirredução , Linfócitos T/metabolismo
13.
Int J Mol Sci ; 22(18)2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34575829

RESUMO

Bisphenol A (BPA) is largely used as a monomer in some types of plastics. It accumulates in tissues and fluids and is able to bypass the placental barrier, affecting various organs and systems. Due to huge developmental processes, children, foetuses, and neonates could be more sensitive to BPA-induced toxicity. To investigate the multi-systemic effects of chronic exposure to a low BPA dose (100 µg/L), pregnant Wistar rats were exposed to BPA in drinking water during gestation and lactation. At weaning, newborn rats received the same treatments as dams until sex maturation. Free and conjugated BPA levels were measured in plasma and adipose tissue; the size of cerebral ventricles was analysed in the brain; morpho-functional and molecular analyses were carried out in the liver with a focus on the expression of inflammatory cytokines and Sirtuin 1 (Sirt1). Higher BPA levels were found in plasma and adipose tissue from BPA treated pups (17 PND) but not in weaned animals. Lateral cerebral ventricles were significantly enlarged in lactating and weaned BPA-exposed animals. In addition, apart from microvesicular steatosis, liver morphology did not exhibit any statistically significant difference for morphological signs of inflammation, hypertrophy, or macrovesicular steatosis, but the expression of inflammatory cytokines, Sirt1, its natural antisense long non-coding RNA (Sirt1-AS LncRNA) and histone deacetylase 1 (Hdac1) were affected in exposed animals. In conclusion, chronic exposure to a low BPA dose could increase the risk for disease in adult life as a consequence of higher BPA circulating levels and accumulation in adipose tissue during the neonatal period.


Assuntos
Compostos Benzidrílicos/efeitos adversos , Água Potável/química , Exposição Ambiental/efeitos adversos , Avaliação do Impacto na Saúde , Fenóis/efeitos adversos , Poluentes Químicos da Água/efeitos adversos , Tecido Adiposo/metabolismo , Animais , Modelos Animais de Doenças , Água Potável/análise , Feminino , Imuno-Histoquímica , Inflamação/etiologia , Inflamação/metabolismo , Inflamação/patologia , Lactação/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , NAD/metabolismo , Estresse Oxidativo , Gravidez , Ratos , Sirtuína 1/metabolismo , Poluentes Químicos da Água/administração & dosagem , Desmame
14.
Biosensors (Basel) ; 11(9)2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34562924

RESUMO

A SPEC/AuNPs/PMB modified electrode was prepared by electrodeposition and electro-polymerization. The electrochemical behavior of reduced nicotinamide adenine dinucleotide (NADH) on the surface of the modified electrode was studied by cyclic voltammetry. A certain amount of substrate and glutamate dehydrogenase (GLDH) were coated on the modified electrode to form a functional enzyme membrane. The ammonia nitrogen in the water sample could be calculated indirectly by measuring the consumption of NADH in the reaction. The results showed that the strength of electro-catalytic current signal was increased by two times; the catalytic oxidation potential was shifted to the left by 0.5 V, and the anti-interference ability of the sensor was enhanced. The optimum substrate concentration and enzyme loading were determined as 1.3 mM NADH, 28 mM α-Ketoglutarate and 2.0 U GLDH, respectively. The homemade ceramic heating plate controlled the working electrode to work at 37 °C. A pH compensation algorithm based on piecewise linear interpolation could reduce the measurement error to less than 3.29 µM. The biosensor exhibited good linearity in the range of 0~300 µM with a detection limit of 0.65 µM NH4+. Compared with standard Nessler's method, the recoveries were 93.71~105.92%. The biosensor was found to be stable for at least 14 days when refrigerated and sealed at 4 °C.


Assuntos
Compostos de Amônio , Aquicultura , Monitoramento Ambiental/instrumentação , Poluentes Químicos da Água/análise , Técnicas Biossensoriais , Catálise , Eletrodos , Monitoramento Ambiental/métodos , Ouro , Nanopartículas Metálicas , NAD , Oxirredução
15.
Cells ; 10(9)2021 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-34572089

RESUMO

According to the U.S. Special Operations Command (SOCOM), new clinical trials of an anti-aging oral treatment using nicotinamide adenine nucleotide are planned for 2022. All over the globe, the discovery of the fountain of youth is still a great goal to reach, not only among aging researchers, since people desire to stay longer healthy and feel young when reaching old age. Since the 1960s, women delaying pregnancy to pursue higher educational levels and a career path has contributed to drastically diminished overall female fertility rates (e.g., number of born offspring/woman). Consequently, a growing number of advanced-aged women depend on assisted reproductive technologies (ART) to become pregnant. In 2019, the Society for Assisted Reproductive Technology reported 293,672 cycles for oocyte retrieval. This change of demographics influenced women's age of having their first child, which has increased significantly. However, their reproductive tract shows hallmarks of aging very early in life without an effective preventive treatment. Therefore, we will present whether NAD+ could help to prevent oocyte aging.


Assuntos
Envelhecimento , Preservação da Fertilidade/métodos , NAD/farmacologia , Oócitos/fisiologia , Reprodução , Técnicas de Reprodução Assistida/normas , Feminino , Humanos , Oócitos/citologia , Oócitos/efeitos dos fármacos , Gravidez
16.
Curr Opin Pharmacol ; 60: 291-297, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34507029

RESUMO

Nicotinamide adenine dinucleotide (NAD) is essential for cellular physiological processes, directly or indirectly affecting metabolism and gene expression. The decline of NAD+ levels in the heart is accompanied by aging, causing cardiac pathological remodeling and dysfunction. Niacinamide mononucleotide (NMN) has emerged as a precursor to alleviate age-related cardiac pathophysiological changes by improving cardiac NAD+ homeostasis. Preclinical trials on the efficacy and safety of intaking NMN have shown encouraging results, revealing a cardioprotective effect without significant side effects. Strategies for improving the effectiveness of NMN are also evolving. The present review aimed to summarize the potentials of NMN as a nutraceutical against cardiac aging and highlight the relationship between NMN supplementation and cardiac protection.


Assuntos
Envelhecimento , Mononucleotídeo de Nicotinamida , Suplementos Nutricionais , Humanos , NAD , Niacinamida
17.
Redox Biol ; 46: 102112, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34537677

RESUMO

The multifunctional nature of human flavoproteins is critically linked to their ability to populate multiple conformational states. Ligand binding, post-translational modifications and disease-associated mutations can reshape this functional landscape, although the structure-function relationships of these effects are not well understood. Herein, we characterized the structural and functional consequences of two mutations (the cancer-associated P187S and the phosphomimetic S82D) on different ligation states which are relevant to flavin binding, intracellular stability and catalysis of the disease-associated NQO1 flavoprotein. We found that these mutations affected the stability locally and their effects propagated differently through the protein structure depending both on the nature of the mutation and the ligand bound, showing directional preference from the mutated site and leading to specific phenotypic manifestations in different functional traits (FAD binding, catalysis and inhibition, intracellular stability and pharmacological response to ligands). Our study thus supports that pleitropic effects of disease-causing mutations and phosphorylation events on human flavoproteins may be caused by long-range structural propagation of stability effects to different functional sites that depend on the ligation-state and site-specific perturbations. Our approach can be of general application to investigate these pleiotropic effects at the flavoproteome scale in the absence of high-resolution structural models.


Assuntos
Mutação de Sentido Incorreto , NAD(P)H Desidrogenase (Quinona) , Flavina-Adenina Dinucleotídeo/metabolismo , Humanos , NAD , NAD(P)H Desidrogenase (Quinona)/genética , NAD(P)H Desidrogenase (Quinona)/metabolismo , Ligação Proteica , Quinonas
18.
Talanta ; 234: 122681, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364481

RESUMO

Hypoxia refers to the lack of oxygen supply to cells or tissues. The overexpression of nitroreductase has been shown to be closely related to the degree of hypoxia, which leads to the level of nitroreductase (NTR) being used as an indicator of hypoxia. We reported a facile visual detection of NTR based on the aggregation of gold and silver alloy nanoparticles. Compared with gold nanoparticles (AuNPs), the aggregation behavior of Au80Ag20 NPs caused a more prominent color change. Copper ions (Cu2+) can be rapidly reduced by nicotinamide adenine dinucleotide (NADH) under the catalysis of Au80Ag20 NPs. But NADH is consumed as an electron donor during the catalytic reduction reaction of p-nitrophenol (pNP) by NTR. A decrease of NADH amount results in the aggregation of Au80Ag20 NPs by the excess Cu2+ and different aggregation degrees of Au80Ag20 NPs lead to observable color change. A linear correlation of A600/A505 = 0.0285 [NTR]+0.361 (R2 = 0.980) was obtained with a limit of detection (LOD) of 0.23 µg/mL for UV-vis spectrophotometer. For visual detection, the values of R/B against the concentration of NTR obtains a calibration curve of R/B = -0.031 [NTR]+ 1.54 (R2 = 0.985) with a LOD of 0.76 µg/mL, which is of the same order of magnitude as the UV-vis spectrophotometer analysis. As a comparison, Au80Ag20 NPs was replaced by several different composition nanoparticles (Au NPs, Au70Ag30 NPs, Au50Ag50 NPs) to be a chromogenic substrate, and the results suggest the Au80Ag20 NPs is the most sensitive substrate in our assay. Selectivity tests showed that the detection system did not respond to other common substances, and the reaction mechanism was verified by inhibitor research. Finally, the assay was used on the human serum samples with spiking NTR, and the recovery rates of this assay with UV-vis spectrophotometer were basically consistent with RGB analysis.


Assuntos
Nanopartículas Metálicas , Prata , Ligas , Colorimetria , Cobre , Ouro , Ligas de Ouro , Humanos , Íons , NAD , Nitrorredutases
19.
J Enzyme Inhib Med Chem ; 36(1): 1916-1921, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34461785

RESUMO

An earlier described three-component variant of the Castagnoli-Cushman reaction employing homophthalic anhydrides, carbonyl compound and ammonium acetate was applied towards the preparation of 1-oxo-3,4-dihydroisoquinoline-4-carboxamides with variable substituent in position 3. These compounds displayed inhibitory activity towards poly(ADP-ribose) polymerase (PARP), a clinically validated cancer target. The most potent compound (PARP1/2 IC50 = 22/4.0 nM) displayed the highest selectivity towards PARP2 in the series (selectivity index = 5.5), more advantageous ADME prameters compared to the clinically used PARP inhibitor Olaparib.


Assuntos
Acetatos/química , Antineoplásicos/química , Inibidores de Poli(ADP-Ribose) Polimerases/química , Poli(ADP-Ribose) Polimerases/metabolismo , Quinolonas/química , Acetatos/farmacologia , Sequência de Aminoácidos , Antineoplásicos/farmacologia , Sítios de Ligação , Dano ao DNA/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , NAD/metabolismo , Ftalazinas/farmacologia , Piperazinas/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Ligação Proteica , Conformação Proteica , Relação Estrutura-Atividade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...