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1.
Int J Mol Sci ; 25(3)2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38339063

RESUMO

Here we use the SCIREQ InExpose system to simulate a biologically relevant vaping model in mice to investigate the role of calcium signaling in vape-dependent pulmonary disease as well as to investigate if there is a gender-based difference of disease. Male and female mice were vaped with JUUL Menthol (3% nicotine) using the SCIREQ InExpose system for 2 weeks. Additionally, 2-APB, a known calcium signaling inhibitor, was administered as a prophylactic for lung disease and damage caused by vaping. After 2 weeks, mice were exposed to lipopolysaccharide (LPS) to mimic a bacterial infection. Post-infection (24 h), mice were sacrificed, and bronchoalveolar lavage fluid (BALF) and lungs were taken. Vaping primed the lungs for worsened disease burden after microbial challenge (LPS) for both males and females, though females presented increased neutrophilia and inflammatory cytokines post-vape compared to males, which was assessed by flow cytometry, and cytokine and histopathological analysis. This increased inflammatory burden was controlled by calcium signaling inhibition, suggesting that calcium dysregulation may play a role in lung injury caused by vaping in a gender-dependent manner.


Assuntos
Pneumopatias , Pneumonia , Vaping , Masculino , Feminino , Camundongos , Animais , Vaping/efeitos adversos , Lipopolissacarídeos/toxicidade , Pneumonia/etiologia , Pneumonia/patologia , Pulmão/patologia , Líquido da Lavagem Broncoalveolar , Citocinas , Inflamação
2.
Chem Res Toxicol ; 35(12): 2194-2209, 2022 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-36480683

RESUMO

The chemosensory experiences evoked by flavors encompass a number of unique sensations that include olfactory stimuli (smell), gustatory stimuli (taste, i.e., salty, sweet, sour, bitter, and umami (also known as "savoriness")), and chemesthesis (touch). As such, the responses evoked by flavors are complex and, as briefly stated above, involve multiple perceptive mechanisms. The practice of adding flavorings to tobacco products dates back to the 17th century but is likely much older. More recently, the electronic cigarette or "e-cigarette" and its accompanying flavored e-liquids emerged on to the global market. These new products contain no combustible tobacco but often contain large concentrations (reported from 0 to more than 50 mg/mL) of nicotine as well as numerous flavorings and/or flavor chemicals. At present, there are more than 400 e-cigarette brands available along with potentially >15,000 different/unique flavored products. However, surprisingly little is known about the flavors/flavor chemicals added to these products, which can account for >1% by weight of some e-liquids, and their resultant chemosensory experiences, and the US FDA has done relatively little, until recently, to regulate these products. This article will discuss e-cigarette flavors and flavor chemicals, their elicited responses, and their sensory effects in some detail.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina , Produtos do Tabaco , Vaping , Aromatizantes , Nicotiana , Sensação , Percepção
3.
Food Chem Toxicol ; 163: 112923, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35318090

RESUMO

It is currently understood that tobacco smoking is a major cause of pulmonary disease due to pulmonary/lung inflammation. However, due to a highly dynamic market place and an abundance of diverse products, less is known about the effects of e-cigarette (E-cig) use on the lung. In addition, varieties of E-cig liquids (e-liquids), which deliver nicotine and numerous flavor chemicals into the lungs, now number in the 1000s. Thus, a critical need exists for safety evaluations of these E-cig products. Herein, we employed a "2-stage in vivo screening platform" (zebrafish to mouse) to assess the safety profiles of e-liquids. Using the zebrafish, we collected embryo survival data after e-liquid exposure as well as neutrophil migration data, a key hallmark for a pro-inflammatory response. Our data indicate that certain e-liquids induce an inflammatory response in our zebrafish model and that e-liquid exposure alone results in pro-inflammatory lung responses in our C57BL/6J model, data collected from lung staining and ELISA analysis, respectively, in the mouse. Thus, our platform can be used as an initial assessment to ascertain the safety profiles of e-liquid using acute inflammatory responses (zebrafish, Stage 1) as our initial metric followed by chronic studies (C57BL/6J, Stage 2).


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina , Pneumonia , Vaping , Animais , Estudos de Viabilidade , Inflamação/induzido quimicamente , Camundongos , Camundongos Endogâmicos C57BL , Pneumonia/induzido quimicamente , Vaping/efeitos adversos , Peixe-Zebra
4.
Biology (Basel) ; 10(10)2021 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-34681152

RESUMO

Pulmonary diseases present a significant burden worldwide and lead to severe morbidity and mortality. Lung inflammation caused by interactions with either viruses, bacteria or fungi is a prominent characteristic of many pulmonary diseases. Tobacco smoke and E-cig use ("vaping") are considered major risk factors in the development of pulmonary disease as well as worsening disease prognosis. However, at present, relatively little is known about the mechanistic actions by which smoking and vaping may worsen the disease. One theory suggests that long-term vaping leads to Ca2+ signaling dysregulation. Ca2+ is an important secondary messenger in signal transduction. Cellular Ca2+ concentrations are mediated by a complex series of pumps, channels, transporters and exchangers that are responsible for triggering various intracellular processes such as cell death, proliferation and secretion. In this review, we provide a detailed understating of the complex series of components that mediate Ca2+ signaling and how their dysfunction may result in pulmonary disease. Furthermore, we summarize the recent literature investigating the negative effects of smoking and vaping on pulmonary disease, cell toxicity and Ca2+ signaling. Finally, we summarize Ca2+-mediated pharmacological interventions that could potentially lead to novel treatments for pulmonary diseases.

5.
PLoS One ; 16(8): e0256166, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34383849

RESUMO

As electronic cigarette (E-cig) use, also known as "vaping", has rapidly increased in popularity, data regarding potential pathologic effects are recently emerging. Recent associations between vaping and lung pathology have led to an increased need to scrutinize E-cigs for adverse health impacts. Our previous work (and others) has associated vaping with Ca2+-dependent cytotoxicity in cultured human airway epithelial cells. Herein, we develop a vaped e-liquid pulmonary exposure mouse model to evaluate vaping effects in vivo. Using this model, we demonstrate lung pathology through the use of preclinical measures, that is, the lung wet: dry ratio and lung histology/H&E staining. Further, we demonstrate that acute vaping increases macrophage chemotaxis, which was ascertained using flow cytometry-based techniques, and inflammatory cytokine production, via Luminex analysis, through a Ca2+-dependent mechanism. This increase in macrophage activation appears to exacerbate pulmonary pathology resulting from microbial infection. Importantly, modulating Ca2+ signaling may present a therapeutic direction for treatment against vaping-associated pulmonary inflammation.


Assuntos
Cálcio/metabolismo , Misturas Complexas/efeitos adversos , Infecções por Klebsiella/etiologia , Klebsiella pneumoniae/patogenicidade , Pneumonia Bacteriana/etiologia , Vaping/efeitos adversos , Animais , Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/imunologia , Quimiotaxia/imunologia , Sistemas Eletrônicos de Liberação de Nicotina , Expressão Gênica , Humanos , Interferon gama/genética , Interferon gama/imunologia , Interleucina-6/genética , Interleucina-6/imunologia , Infecções por Klebsiella/imunologia , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/patologia , Klebsiella pneumoniae/fisiologia , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Pulmão/patologia , Ativação de Macrófagos/imunologia , Macrófagos/imunologia , Macrófagos/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Estresse Oxidativo , Pneumonia Bacteriana/imunologia , Pneumonia Bacteriana/microbiologia , Pneumonia Bacteriana/patologia , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologia
6.
MethodsX ; 8: 101383, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34430279

RESUMO

Due to its role in brain development, the DYRK1A kinase (dual-specificity tyrosine phosphorylation-regulated kinase 1a) has been proposed as a drug target for Down syndrome, and diseases associated with neurodegeneration including Alzheimer's and Parkinson's. Other diseases in which DYRK1A is implicated include cancer and diabetes. Hence, there is need for potent and selective DYRK1A inhibitors. To screen large diversity compound libraries versus DYRK1A requires the development of a cost-effective high-throughput screen. In this study, we have taken a commercial time-resolved fluorescence energy transfer (TR-FRET)-based assay for DYRK1A and optimized for smaller volumes and homogenous format at room temperature. Tracer and enzyme concentrations were determined. DYRK1A-GST, anti-GST Ab and tracer were pre-combined and total assay volume reduced 2-fold. The assay was validated using whole plate minimum and maximum signal wells with a Z' of 0.7-0.8 determined. Overall, this method:•Results in an optimized low volume, homogenous and validated assay for DYRK1A.•Delivers a cost effective high-throughput assay format for DYRK1A inhibitor screening.

7.
Data Brief ; 37: 107189, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34141844

RESUMO

The data presented in this article support the accompanying research article "Identification of harmine and ß-carboline analogs from a high-throughput screen of an approved drug collection; profiling as differential inhibitors of DYRK1A and monoamine oxidase A and for in vitro and in vivo anti-cancer studies" [1]. As DYRK1A (dual-specificity tyrosine phosphorylation-regulated kinase 1a) plays a role in the pathophysiology of a number of diseases including diabetes, cancer and neurodegeneration [2], [3], [4], the identification of DYRK1A inhibitors is of significant interest. This data article details the hits identified from a DYRK1A high-throughput screen of a small molecule compound library containing over 95% approved drugs. Twenty-two compounds were identified with >50% inhibition, including harmine and four of its analogs. Subsequent profiling of these harmine analogs using glioma cancer cell lines and high-content image analysis identified those with effects on growth and cytotoxicity.

8.
Front Physiol ; 12: 634839, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34040540

RESUMO

Though the current preponderance of evidence indicates the toxicity associated with the smoking of tobacco products through conventional means, less is known about the role of "vaping" in respiratory disease. "Vaping" is described as the use of electronic cigarettes (E-Cigarettes or E-Cigs), which has only more recently been available to the public (∼10 years) but has quickly emerged as a popular means of tobacco consumption worldwide. The World Health Organization (WHO) declared the SARS-CoV-2 outbreak as a global pandemic in March 2020. SARS-CoV-2 can easily be transmitted between people in close proximity through direct contact or respiratory droplets to develop coronavirus infectious disease 2019 (COVID-19). Symptoms of COVID-19 range from a mild flu-like illness with high fever to severe respiratory distress syndrome and death. The risk factors for increased disease severity remain unclear. Herein, we utilize a murine-tropic coronavirus (beta coronavirus) MHV-A59 along with a mouse model and measures of pathology (lung weight/dry ratios and histopathology) and inflammation (ELISAs and cytokine array panels) to examine whether vaping may exacerbate the pulmonary disease severity of coronavirus disease. While vaping alone did result in some noted pathology, mice exposed with intranasal vaped e-liquid suffered more severe mortality due to pulmonary inflammation than controls when exposed to coronavirus infection. Our data suggest a role for vaping in increased coronavirus pulmonary disease in a mouse model. Furthermore, our data indicate that disease exacerbation may involve calcium (Ca2+) dysregulation, identifying a potential therapeutic intervention.

9.
Biology (Basel) ; 10(4)2021 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33918192

RESUMO

The importance of intracellular calcium (Ca2+) in regulating integral biological functions such as cell division, cell motility, autophagy, apoptosis and gene transcription through its capacity as a ubiquitous second messenger is clear [...].

10.
Eur J Pharm Sci ; 162: 105821, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33781856

RESUMO

DYRK1A (dual-specificity tyrosine phosphorylation-regulated kinase 1a) is highly expressed in glioma, an aggressive brain tumor, and has been proposed as a therapeutic target for cancer. In the current study, we have used an optimized and validated time-resolved fluorescence energy transfer (TR-FRET)-based DYRK1A assay for high-throughput screening (HTS) in 384-well format. A small-scale screen of the FDA-approved Prestwick drug collection identified the ß-carboline, harmine, and four related analogs as DYRK1A inhibitors. Hits were confirmed by dose response and in an orthogonal DYRK1A assay. Harmine's potential therapeutic use has been hampered by its off-target activity for monoamine oxidase A (MAO-A) which impacts multiple nervous system targets. Selectivity profiling of harmine and a broader collection of analogs allowed us to map some divergent SAR (structure-activity relationships) for the DYRK1A and MAO-A activities. The panel of harmine analogs had varying activities in vitro in glioblastoma (GBM) cell lines when tested for anti-proliferative effects using a high content imaging assay. In particular, of the identified analogs, harmol was found to have the best selectivity for DYRK1A over MAO-A and, when tested in a glioma tumor xenograft model, harmol demonstrated a better therapeutic window compared to harmine.


Assuntos
Antineoplásicos/farmacologia , Inibidores da Monoaminoxidase , Neoplasias , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/antagonistas & inibidores , Carbolinas , Harmina/farmacologia , Ensaios de Triagem em Larga Escala , Humanos , Monoaminoxidase , Inibidores da Monoaminoxidase/farmacologia , Quinases Dyrk
11.
Toxicol Lett ; 337: 46-56, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33253780

RESUMO

RATIONALE: The popularity of new and emerging tobacco products such as E-cigarettes (E-cigs) is rapidly expanding worldwide. However, uncertainties surrounding the potential health consequences due to the use of such products exist and warrant further study. METHODS: Cultured A549 and Calu-3 airway epithelia were exposed to three out of the eight types of JUUL brand e-liquids ("Mint", "Virginia Tobacco" and "Menthol", all containing 3% nicotine at 1% and 3% (vol/vol) dilutions) and assessed for viability using a resazurin-based assay. Intracellular Ca2+ levels were measured using fluorescent indicators and pro-inflammatory cytokine levels were monitored by quantitative PCR (qPCR). Cultures were also analyzed by flow cytometry to evaluate apoptotic markers and cell viability. RESULTS: Exposing the airway epithelial cells to the flavored JUUL e-liquids led to significant cytotoxicity, with the "Mint" flavor being the overall most cytotoxic. The "Mint" flavored e-liquid also led to significant elevations in intracellular Ca2+ and upregulation of the pro-inflammatory cytokine IL-6 and early apoptotic marker Annexin V. CONCLUSIONS: JUUL e-liquid challenge resulted in a loss of airway epithelial cell viability, induced pro-inflammatory responses and eventually caused apoptosis.


Assuntos
Sinalização do Cálcio/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Citoplasma/efeitos dos fármacos , Citoplasma/metabolismo , Sistemas Eletrônicos de Liberação de Nicotina , Células Epiteliais/efeitos dos fármacos , Mucosa Respiratória/citologia , Células A549 , Apoptose/efeitos dos fármacos , Cálcio/metabolismo , Linhagem Celular , Citocinas/análise , Citocinas/metabolismo , Aromatizantes/toxicidade , Humanos , Mentha , Nicotina/análise , Mucosa Respiratória/efeitos dos fármacos
12.
J Appl Toxicol ; 41(3): 493-505, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33034066

RESUMO

"Pod-based" e-cigarettes such as JUUL are currently the most prevalent electronic nicotine delivery systems (ENDS) in the United States. JUUL-type ENDS utilize nicotine salts protonated with benzoic acid rather than freebase nicotine. However, limited information is available on the cellular effects of these products. Cytoplasmic Ca2+ is a universal second messenger that controls many cellular functions including cell growth and cell death. Of note, dysregulation of cell Ca2+ homeostasis has been linked with several disease processes including autoimmune disease and several types of cancer. We exposed HEK293T cells and THP-1 macrophage-like cells to different JUUL e-liquids. We evaluated their effects on cellular viability and Ca2+ signaling by measuring fluorescence from calcein-AM/propidium iodide and Fluo-4, respectively. E-liquid autofluorescence was used to look for e-liquid permeation into cells. To identify the mechanisms behind the Ca2+ responses, different inhibitors of Ca2+ channels and phospholipase C signaling were used. JUUL e-liquids caused significant cytotoxic effects, with "Mint" flavor being the most cytotoxic. The Mint flavored e-liquid also caused a significant elevation in cytoplasmic Ca2+ . Using autofluorescence, the permeation of JUUL e-liquids into live cells was confirmed, indicating that intracellular organelles are directly exposed to e-liquids. Further studies identified the endoplasmic reticulum as being the source of e-liquid-induced changes in cytoplasmic Ca2+ . Nicotine salt-based e-liquids cause cytotoxicity and elevate cytoplasmic Ca2+ , indicating that they can exert biological effects beyond what would be expected with nicotine alone. These effects are flavor-dependent, and we propose that flavored e-liquids be reassessed for potential lung toxicity.


Assuntos
Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas/efeitos dos fármacos , Vapor do Cigarro Eletrônico/toxicidade , Sistemas Eletrônicos de Liberação de Nicotina , Aromatizantes/toxicidade , Nicotina/toxicidade , Humanos , Estados Unidos
13.
Data Brief ; 15: 577-583, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29071296

RESUMO

The data presented in this article support the accompanying research article "Identification of a DYRK1A-mediated phosphorylation site within the nuclear localization sequence of the hedgehog transcription factor GLI1" (Ehe et al., 2017) [1]. Although it has been demonstrated that DYRK1A (dual-specificity tyrosine-regulated kinase 1A) can phosphorylate the hedgehog pathway transcription factor GLI1 (GLIoma-associated oncogene homolog 1) and promote its nuclear localization, the DYRK1A-mediated sites of phosphorylation on GLI1 involved were not fully known. This article details the mass spectrometry methods and resulting dataset for the peptides identified from GLI1 when incubated with DYRK1A under varying conditions. The data include details of sequence coverage and all phospho-peptides identified.

14.
Biochem Biophys Res Commun ; 491(3): 767-772, 2017 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-28735864

RESUMO

GLI1 is a key downstream transcription effector of the Hedgehog (Hh) signaling pathway that is involved in promoting cell growth, differentiation and tissue patterning in embryonic development. GLI1 over-activation and its nuclear localization has also been linked to the increased aggressiveness of a number of cancers. It has previously been demonstrated that DYRK1A (dual-specificity tyrosine-regulated kinase 1A) can phosphorylate GLI1 and promote GLI1 nuclear localization and its transcriptional activity. Utilizing recombinant human GLI1 and DYRK1A proteins and phospho-peptide mass spectrometry, we demonstrated that GLI1 is phosphorylated by DYRK1A at Ser408, a phospho-site that falls within the putative nuclear localization sequence (NLS) of GLI1, suggesting a possible mechanistic role in modulating its translocation. Further, we showed that the Ser408 site on GLI1 was not phosphorylated in the presence of the selective DYRK1A inhibitor harmine. The data described herein provide the first identification of a DYRK1A-mediated site of phosphorylation on GLI1 within its NLS and may serve as a valuable mechanism for further understanding Hh signaling modulation.


Assuntos
Sinais de Localização Nuclear/química , Sinais de Localização Nuclear/metabolismo , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Tirosina Quinases/química , Proteínas Tirosina Quinases/metabolismo , Proteína GLI1 em Dedos de Zinco/química , Proteína GLI1 em Dedos de Zinco/metabolismo , Sequência de Aminoácidos , Sítios de Ligação , Células HEK293 , Proteínas Hedgehog/química , Proteínas Hedgehog/metabolismo , Humanos , Fosforilação , Ligação Proteica , Quinases Dyrk
15.
Biochem J ; 470(3): 331-42, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26195823

RESUMO

Autophagy is a complex pathway regulated by numerous signalling events that recycles macromolecules and may be perturbed in lysosomal storage disorders (LSDs). During autophagy, aberrant regulation of the lysosomal Ca(2+) efflux channel TRPML1 [transient receptor potential mucolipin 1 (MCOLN1)], also known as MCOLN1, is solely responsible for the human LSD mucolipidosis type IV (MLIV); however, the exact mechanisms involved in the development of the pathology of this LSD are unknown. In the present study, we provide evidence that the target of rapamycin (TOR), a nutrient-sensitive protein kinase that negatively regulates autophagy, directly targets and inactivates the TRPML1 channel and thereby functional autophagy, through phosphorylation. Further, mutating these phosphorylation sites to unphosphorylatable residues proved to block TOR regulation of the TRPML1 channel. These findings suggest a mechanism for how TOR activity may regulate the TRPML1 channel.


Assuntos
Mucolipidoses/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Canais de Potencial de Receptor Transitório/metabolismo , Proteínas Quinases Ativadas por AMP/antagonistas & inibidores , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Sequência de Aminoácidos , Animais , Animais Geneticamente Modificados , Autofagia , Sítios de Ligação , Sinalização do Cálcio , Proteínas de Drosophila/antagonistas & inibidores , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Feminino , Técnicas de Silenciamento de Genes , Genes de Insetos , Células HEK293 , Humanos , Masculino , Modelos Biológicos , Dados de Sequência Molecular , Mucolipidoses/genética , Mutagênese Sítio-Dirigida , Fosforilação , Interferência de RNA , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Canais de Potencial de Receptor Transitório/genética
16.
J Exp Neurosci ; 9(Suppl 2): 81-91, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-27081317

RESUMO

Autophagy is a complex pathway regulated by numerous signaling events that recycles macromolecules and can be perturbed in lysosomal storage diseases (LSDs). The concept of LSDs, which are characterized by aberrant, excessive storage of cellular material in lysosomes, developed following the discovery of an enzyme deficiency as the cause of Pompe disease in 1963. Great strides have since been made in better understanding the biology of LSDs. Defective lysosomal storage typically occurs in many cell types, but the nervous system, including the central nervous system and peripheral nervous system, is particularly vulnerable to LSDs, being affected in two-thirds of LSDs. This review provides a summary of some of the better characterized LSDs and the pathways affected in these disorders.

17.
Biol Open ; 2(12): 1321-3, 2013 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-24337116

RESUMO

The maintenance of energetic homeostasis in the face of limited available nutrients is a complex problem faced by all organisms. One important mechanism to maintain energetic homeostasis involves the activation of the energy sensor AMP-activated protein kinase (AMPK). AMPK is a cell-autonomous energy sensor that is highly sensitive to and regulated by the ATP to ADP and ATP to AMP ratios. However, the genetic analysis of AMPK signaling in vertebrates has been complicated by the existence of multiple redundant AMPK subunits. Here, we describe the identification of mutations in the single Drosophila melanogaster AMPK catalytic subunit (AMPKα) and their implications for neural maintenance and integrity. This article provides a citation replacement for previously published ampkα alleles, transgenes and neuronal phenotypes, which remain accurate; however, they were used in a previously published study that has subsequently been retracted (Mirouse et al., 2013).

18.
Mol Biol Cell ; 23(2): 381-9, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22114351

RESUMO

AMP-activated protein kinase (AMPK) is a key energy sensor that regulates metabolism to maintain cellular energy balance. AMPK activation has also been proposed to mimic benefits of caloric restriction and exercise. Therefore, identifying downstream AMPK targets could elucidate new mechanisms for maintaining cellular energy homeostasis. We identified the phosphotransferase nucleoside diphosphate kinase (NDPK), which maintains pools of nucleotides, as a direct AMPK target through the use of two-dimensional differential in-gel electrophoresis. Furthermore, we mapped the AMPK/NDPK phosphorylation site (serine 120) as a functionally potent enzymatic "off switch" both in vivo and in vitro. Because ATP is usually the most abundant cellular nucleotide, NDPK would normally consume ATP, whereas AMPK would inhibit NDPK to conserve energy. It is intriguing that serine 120 is mutated in advanced neuroblastoma, which suggests a mechanism by which NDPK in neuroblastoma can no longer be inhibited by AMPK-mediated phosphorylation. This novel placement of AMPK upstream and directly regulating NDPK activity has widespread implications for cellular energy/nucleotide balance, and we demonstrate in vivo that increased NDPK activity leads to susceptibility to energy deprivation-induced death.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Homeostase , Núcleosídeo-Difosfato Quinase/metabolismo , Fosfosserina/metabolismo , Trifosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Animais , Encéfalo/enzimologia , Linhagem Celular Tumoral , Drosophila melanogaster/enzimologia , Técnicas de Inativação de Genes , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Dados de Sequência Molecular , Mutação , Núcleosídeo-Difosfato Quinase/antagonistas & inibidores , Núcleosídeo-Difosfato Quinase/genética , Fosforilação , Eletroforese em Gel Diferencial Bidimensional
19.
Int J Syst Evol Microbiol ; 57(Pt 10): 2191-2193, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17911280

RESUMO

Strain 39E(T), originally characterized as Clostridium thermohydrosulfuricum strain 39E and later renamed as Thermoanaerobacter ethanolicus strain 39E, shows less than 97 % 16S rRNA gene sequence similarity with the type strain of the type species of the genus Thermoanaerobacter, T. ethanolicus strain JW 200(T). On the basis of a polyphasic analysis that included DNA-DNA hybridization studies with the subspecies of Thermoanaerobacter brockii, its closest phylogenetic relatives, strain 39E(T) represents a novel species of the genus Thermoanaerobacter, for which the name Thermoanaerobacter pseudethanolicus sp. nov. is proposed. The type strain is 39E(T) (=DSM 2355(T)=ATCC 33223(T)).


Assuntos
Thermoanaerobacter/classificação , Anaerobiose , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Genes de RNAr , Temperatura Alta , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Filogenia , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico , Thermoanaerobacter/citologia , Thermoanaerobacter/genética , Thermoanaerobacter/fisiologia
20.
Biochem Biophys Res Commun ; 353(2): 389-93, 2007 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-17178108

RESUMO

NAD(P)H:quinone oxidoreductase (NQO1; EC 1.6.99.2) catalyzes a two-electron transfer involved in the protection of cells from reactive oxygen species. These reactive oxygen species are often generated by the one-electron reduction of quinones or quinone analogs. We report here on the previously unreported Fe(III) reduction activity of human NQO1. Under steady state conditions with Fe(III) citrate, the apparent Michaelis-Menten constant (Km(app)) was approximately 0.3 nM and the apparent maximum velocity (Vmax(app)) was 16 U mg(-1). Substrate inhibition was observed above 5 nM. NADH was the electron donor, Km(app)= 340 microM and Vmax(app) = 46 Umg(-1). FAD was also a cofactor with a Km(app) of 3.1 microM and Vmax(app) of 89 U mg(-1). The turnover number for NADH oxidation was 25 s(-1). Possible physiological roles of the Fe(III) reduction by this enzyme are discussed.


Assuntos
Ferro/química , NAD(P)H Desidrogenase (Quinona)/química , Catálise , Ativação Enzimática , Humanos , Oxirredução , Especificidade por Substrato
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