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1.
Artigo em Inglês | MEDLINE | ID: mdl-32361631

RESUMO

Accumulation of Immune Responsive Gene 1(IRG1) in macrophage induced by lipopolysaccharide (LPS) and interferon gamma (IFN-γ) leads to production of itaconate by decarboxylation of cis-aconitate. The biology associated with IRG1 and itaconate is not fully understood. A rapid and sensitive method for measurement of itaconate will benefit the study of IRG1 biology. Multiple HPLC and derivatization methods were tested. An ion pairing LC-MS/MS method using tributylamine/formic acid as ion pairing agents and a HypercarbTM guard column we proposed demonstrated better peak shape and better sensitivity for itaconate. The current protocol allows baseline separation of itaconate, citraconate, and cis-aconitate without derivatization and direct analysis of analytes in 80% methanol/water solution to avoid the dry-down step. It provides the limit of quantitation (LOQ) of 30 pg itaconate on column with a 4.5-minute run time. This method is validated for measurement of itaconate and cis-aconitate in RAW264.7 cell extract and cell media in a 96-well plate format. We applied this method to successfully measure the increase of itaconate and the decrease of cis-aconitate in RAW cell extract and cell media after LPS/IFN-γ treatment.


Assuntos
Ácido Aconítico/análise , Extratos Celulares/análise , Succinatos/análise , Espectrometria de Massas em Tandem/métodos , Animais , Técnicas Biossensoriais , Butilaminas/química , Cromatografia Líquida de Alta Pressão , Formiatos/química , Hidroxilaminas/química , Interferon gama/química , Limite de Detecção , Lipopolissacarídeos/química , Macrófagos/química , Camundongos , Células RAW 264.7 , Sensibilidade e Especificidade
2.
Chemosphere ; 247: 125844, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32069708

RESUMO

Biphenyl 2,3-dioxygenase (BphA), a Rieske-type and first enzyme in the aerobic degradation process, plays a key role in the metabolizing process of biphenyl/polychlorinated biphenyl aromatic pollutants in the environment. To understand the catalytic mechanism of biphenyl 2,3-dioxygenase, the conversions leading to the cis-diols are investigated by means of quantum mechanics/molecular mechanics (QM/MM) method. A hydroperoxo-iron (III) species is involved in the enzyme-catalyzed reaction. Herein, we explored the direct reaction mechanism of hydroperoxo-iron (III) species with biphenyl and 4-4'-dichlorobiphenyl. The reaction process involves an epoxide intermediate, it could develop into a carbocation intermediate, and ultimately evolve into a cis-diol product. The important roles of several residues during the dioxygenation process were highlighted. This study may provide theoretical support for further directed mutations and enzymatic engineering of BphA, as well as promote the development of degrading environmentally persistent biphenyl/polychlorinated biphenyl aromatic contaminants.


Assuntos
Compostos de Bifenilo/química , Dioxigenases/metabolismo , Poluentes Ambientais/química , Bifenilos Policlorados/química , Catálise , Dioxigenases/genética , Hidroxilaminas , Hidroxilação , Oxigenases/metabolismo , Bifenilos Policlorados/metabolismo
3.
Sci Total Environ ; 717: 137030, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32062250

RESUMO

Anammox bacteria play an important role in the global nitrogen cycle, but research on anammoxosome structure is still in its initial stages. In particular, the anammox bacteria genome contains nanocompartments gene loci. However, the function and structure of the nanocompartments in anammox bacteria is poorly understood. We apply genetic engineering to demonstrate the self-assembled nanocompartments of anammox bacteria. The encapsulin shell protein (cEnc) and cargo protein hydroxylamine oxidoreductase (HAO) can self-assemble to form regular nanocompartments (about 128 nm in diameter) in vitro. Cell growth curve tests show that nanocompartments help model bacteria resist hydroxylamine (NH2OH) stress. Batch test results and transcriptional data show that cEnc and HAO are highly expressed in response to the negative effects of NH2OH on anammox efficiency, predicting a potential role of nanocompartments in helping anammox bacteria resist NH2OH stress. These findings improve our understanding of the mechanisms by which anammox bacteria respond to harmful environmental metabolites.


Assuntos
Bactérias , Hidroxilamina/farmacologia , Anaerobiose , Proteínas de Bactérias , Hidroxilaminas , Oxirredução , Estresse Fisiológico
4.
Chemosphere ; 250: 126150, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32088614

RESUMO

The pipe deposits from water distribution network are iron-wastes, which could be used as a catalyst of advanced oxidation processes (AOPs). This paper prepared one main composition (α-FeOOH) of pipe deposits and compared the difference of chloramphenicol (CAP) degradation by α-FeOOH-activated hydrogen peroxide/persulfate and α-FeOOH-activated hydrogen peroxide/peroxymonosulfate with hydroxylamine assistance. Several key affecting factors were investigated. The results revealed that the double-oxidant system has a synergy effect in CAP degradation process. The hydroxyl radicals were identified as the predominant radicals in two different degradation processes via electron paramagnetic resonance (EPR) technique. The possible degradation pathways and products were confirmed by liquid chromatography-mass spectrometry (LC-MS). This study provided a theoretic research for pollutant removal by taking full advantage of pipe deposits and advance the development of water quality security in water distribution network in future.


Assuntos
Cloranfenicol/química , Hidroxilamina/química , Poluentes Químicos da Água/química , Catálise , Cloranfenicol/análise , Compostos Férricos/química , Peróxido de Hidrogênio/química , Radical Hidroxila , Hidroxilamina/análise , Hidroxilaminas/química , Ferro/química , Compostos de Ferro , Minerais , Modelos Químicos , Oxidantes , Peróxidos , Poluentes Químicos da Água/análise
5.
J Chromatogr A ; 1609: 460512, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31542208

RESUMO

The simultaneous use of nitrite and sorbate as preservatives in meat products may produce mutagenic compounds such as the ethylnitrolic acid and 2-methyl-1,4-dinitro-pyrrole. We developed a sensitive analytical method with high metrological reliability. After assessing several extraction approaches and chromatographic separation modes, a modified Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) approach was chosen for sample preparation, which were analyzed by reversed-phase liquid chromatography (with C18 as stationary phase) coupled to tandem mass spectrometry. After validation, we confirmed that this method is fit-for-purpose, since it was applied to the analysis of several meat products. Limits of detection were set from 5 to 20 µg kg-1. Satisfactory results were obtained for both compounds, such as precision (CV > 20%) and recoveries (77-92%). This method determine these carcinogenic compounds in processed meats, contributing to the preservation of public health and the improvement of food regulation and control.


Assuntos
Métodos Analíticos de Preparação de Amostras , Hidroxilaminas/análise , Produtos da Carne/análise , Mutagênicos/análise , Nitrilos/análise , Pirróis/química , Espectrometria de Massas em Tandem/métodos , Calibragem , Cromatografia Líquida , Cromatografia de Fase Reversa , Reprodutibilidade dos Testes
6.
Food Chem Toxicol ; 136: 110964, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31730879

RESUMO

Processed meats are classified by the International Agency for Research on Cancer (IARC) as carcinogenic to humans. However, information on the responsible agents and the influence of industrial processing on the increased risk of cancer is still lacking. This study aimed to use cultures of Lactobacillus delbrueckii subsp. bulgaricus LB-UFSC 01 to biodegrade harmful C-nitrous, N-nitro, and C-nitro compounds in processed meat matrix. Firstly, positive results for ethylnitrolic acid (ENA) (>5.00 µg kg-1) and 2-methyl-1,4-dinitro-pyrrole (DNMP) (>12.0 µg kg-1) were obtained in mortadellas produced under different experimental conditions employing preservatives and antioxidants. Mortadellas containing nitrite and sorbate in the ratio of 8:1 (w/w) yielded the highest concentrations of mutagens. However, the treatment with the LB-UFSC 01 culture was able to modulate the harmful compounds in the mortadella samples. Several analytical methods employing liquid chromatography coupled to mass spectrometry and statistical models were employed to identify the metabolites and reaction routes during microbial biotransformation. For the first time, relevant information regarding the formation and degradation of ENA and DNMP in a processed meat model simulating real conditions was presented.


Assuntos
Hidroxilaminas/metabolismo , Lactobacillus delbrueckii/metabolismo , Produtos da Carne/microbiologia , Mutagênicos/metabolismo , Nitrilos/metabolismo , Pirróis/metabolismo , Antioxidantes/química , Ácido Ascórbico/química , Microbiologia de Alimentos , Conservantes de Alimentos/química , Nitrito de Sódio/química , Ácido Sórbico/química
7.
Water Res ; 168: 115093, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31606557

RESUMO

Hydroxylamine showed an outstanding performance on enhancing the oxidation of pollutants in Fe(II) involved advanced oxidation processes, while the detailed reaction schemes have not been fully revealed. Specific functions of hydroxylamine in the oxidation of benzoic acid with Fe(II)/persulfate (PDS) system were explored. With the addition of hydroxylamine, degradation kinetics of benzoic acid deviated from both two-stage kinetics and pseudo first order kinetics, but could be interpreted well with binomial regression analysis. Degradation rate constant (kobs) of benzoic acid was calculated and showed the same variation trend with [hydroxylamine][Fe(III)]2/([Fe(II)][H+])2, the value of which was changed during reaction processes. A detailed kinetic model for simulating the degradation profile of benzoic acid with hydroxylamine acceleration was proposed for the first time and indicated that interactions of hydroxylamine and Fe(III) were fast equilibrium reactions, which was a dominant factor influencing the oxidation kinetics of benzoic acid in Fe(II)/hydroxylamine/PDS system. Comparative study showed that when 1.4 mM of ascorbic acid was added into Fe(II)/PDS system, degradation kinetics of benzoic acid was similar to that enhanced by hydroxylamine. However, when 0.6 mM or 1.0 mM of ascorbic acid was added, oxidation kinetics still presented as the two-stage profile. Kinetic simulations indicated that Fe(II) was produced slower from Fe(III)-ascorbic acid complexes than that with hydroxylamine, which caused the difference in oxidation kinetics. This study could improve our understanding about the effect of hydroxylamine and other reductants in promoting pollutants elimination in Fe(II)/PDS system.


Assuntos
Compostos Ferrosos , Poluentes Químicos da Água , Compostos Férricos , Hidroxilamina , Hidroxilaminas , Cinética , Oxirredução
8.
Bioresour Technol ; 294: 122183, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31683455

RESUMO

Sewage nitritation is a promising process for nitrogen removal, but its practical application is limited by long start-up period and unstable operation. In this study, hydroxylamine (NH2OH) addition and real-time aeration control strategies were adopted for the promotion of sewage nitritation in a sequencing batch reactor. Initially, 4.5 mg/L NH2OH was added into reactor every 24 h to establish nitritation, increasing the nitrite accumulation ratio (NAR) from 1.7% to 93% in 19 d. In the following period, NH2OH addition was stopped and nitritation remained stable over 55 d, with NAR of 97% by real-time aeration control. The aeration duration was determined by characteristic points on pH curve. The main genera of nitrite oxidizing bacteria, Nitrobacter and Nitrospira, were both eliminated from the system, supporting the long-term stability of nitritation. Overall, NH2OH addition and real-time aeration control is an excellent strategy for establishing and maintaining effective sewage nitritation.


Assuntos
Reatores Biológicos , Esgotos , Hidroxilamina , Hidroxilaminas , Nitritos , Nitrogênio , Oxirredução
9.
Exp Eye Res ; 188: 107792, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31499034

RESUMO

Oxidative stress and subsequent chronic inflammation result in dysfunction of the retinal pigment epithelium (RPE) and represent therapeutic targets in the context of age-related macular degeneration (AMD). However, molecular mechanisms that linked oxidative stress and inflammation still unclear. As an important byproduct of oxidative stress, 4-hydroxynonenal (4-HNE) induces apoptosis and lysosome dysregulation of RPE cells. In the present study, we evaluated cytokines production of RPE cells induced by 4-HNE by using cytokine array and confirmed that 4-HNE induced IL-6, IL-1ß and TNF-α production in a concentration dependent manner. Specifically, 4-HNE also induced IL-10 and TGF-ß production in low concentration. Molecular analysis revealed that intracellular HSP70 inhibited 4-HNE-induced production of pro-inflammatory cytokines, and 4-HNE exerted proinflammatory effects in RPE cells by enhancing extracellular release of HSP70, as efflux inhibitor Methyl-ß-cyclodextrin (MBC) treatment significantly blocked the release of HSP70 and decreased IL-6 production of RPE cells induced by 4-HNE. Meanwhile, HSP70 inducer arimoclomol increased intracellular HSP70 production, but showed no influence on its extracellular level, also performed anti-inflammatory effects in 4-HNE-stimulated RPE cells. Whereas the anti-inflammatory effects of paeoniflorin, an HSP70 inducer simultaneously promoted its extracellular efflux, was lower than arimoclomol. In addition, we further confirmed that MBC exhibited synergetic effect with both paeoniflorin and arimoclomol to inhibit the production of proinflammatory cytokines induced by 4-HNE. Taken together, these results indicate that HSP70 plays a vital role in regulating inflammation of RPE cells induced by oxidative stress and might be a potential novel target for clinical treatment of AMD.


Assuntos
Aldeídos/farmacologia , Inibidores de Cisteína Proteinase/farmacologia , Citocinas/metabolismo , Proteínas de Choque Térmico HSP70/metabolismo , Epitélio Pigmentado da Retina/efeitos dos fármacos , Aldeídos/antagonistas & inibidores , Western Blotting , Células Cultivadas , Relação Dose-Resposta a Droga , Humanos , Hidroxilaminas/farmacologia , Epitélio Pigmentado da Retina/metabolismo , Transfecção , beta-Ciclodextrinas/farmacologia
10.
Bioprocess Biosyst Eng ; 42(12): 1983-1992, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31420725

RESUMO

N2O production from NH2OH oxidation involved in a heterotrophic nitrifier Alcaligenes faecalis strain NR was studied. 15N-labeling experiments showed that biological NH2OH consumption by strain NR played a dominant role in N2O production, although chemical reaction between NH2OH and O2 indeed existed. Hydroxylamine oxidoreductase (HAO) from strain NR was partially purified by (NH4)2SO4 fractionation and DEAE Cartridge chromatography. The maximum activity of HAO was 9.60 mU with a specific activity of 92.04 mU/(mg protein) when K3Fe(CN)6 was used as an electron acceptor. The addition of Ca2+ promoted the HAO activity, while the presence of Mn2+ inhibited the enzyme activity. The optimal temperature and pH for HAO activity were 30 °C and 8. Analysis of enzyme-catalyzed products demonstrated that NH2OH oxidation catalyzed by HAO from strain NR played significant role in the production of N2O.


Assuntos
Alcaligenes faecalis/enzimologia , Microbiologia Industrial , Óxido Nitroso/metabolismo , Oxirredutases/biossíntese , Aerobiose , Cálcio/química , Catálise , Cromatografia , Meios de Cultura , Elétrons , Concentração de Íons de Hidrogênio , Hidroxilaminas , Íons , Manganês/química , Espectrometria de Massas , Isótopos de Nitrogênio , Oxirredução , Temperatura
11.
Curr Opin Neurol ; 32(5): 758-763, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31335338

RESUMO

PURPOSE OF REVIEW: To review new developments in the field of amyotrophic lateral sclerosis (ALS) clinical trial design and to review the implications of the latest ALS clinical trials. RECENT FINDINGS: There has been substantial reflection on how clinical trials in ALS are best conducted. The revised Airlie House recommendations are an important milestone and should guide trial design. In addition, innovations using individualized risk-based eligibility criteria, adaptive designs, joint modelling, patient-centred approaches, and remote collection of data show real promise. Edaravone was shown to have benefit on function in a well defined subset of patients with ALS, although there are concerns about the generalizability of the findings. Studies of arimoclomol, inosine, and cellular therapies have demonstrated promising signals in early phase work and are being taken forward into larger studies. Well conducted studies of rasagaline did not show an effect on primary outcome measures. SUMMARY: For many decades there has been regular disappointment with the results of clinical trials. With the innovations in trial design and advances in our basic understanding of the biology of ALS, the prospects for a step change in treatments for people affected by ALS are strong.


Assuntos
Esclerose Amiotrófica Lateral/tratamento farmacológico , Ensaios Clínicos como Assunto , Edaravone/uso terapêutico , Hidroxilaminas/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Humanos , Projetos de Pesquisa , Resultado do Tratamento
12.
Mol Pharmacol ; 96(1): 99-108, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31036695

RESUMO

C-terminal binding proteins (CtBP1/2) are oncogenic transcriptional coregulators and dehydrogenases often overexpressed in multiple solid tumors, including breast, colon, and ovarian cancer, and associated with poor survival. CtBPs act by repressing expression of genes responsible for apoptosis (e.g., PUMA, BIK) and metastasis-associated epithelial-mesenchymal transition (e.g., CDH1), and by activating expression of genes that promote migratory and invasive properties of cancer cells (e.g., TIAM1) and genes responsible for enhanced drug resistance (e.g., MDR1). CtBP's transcriptional functions are also critically dependent on oligomerization and nucleation of transcriptional complexes. Recently, we have developed a family of CtBP dehydrogenase inhibitors, based on the parent 2-hydroxyimino-3-phenylpropanoic acid (HIPP), that specifically disrupt cancer cell viability, abrogate CtBP's transcriptional function, and block polyp formation in a mouse model of intestinal polyposis that depends on CtBP's oncogenic functions. Crystallographic analysis revealed that HIPP interacts with CtBP1/2 at a conserved active site tryptophan (W318/324; CtBP1/2) that is unique among eukaryotic D2-dehydrogenases. To better understand the mechanism of action of HIPP-class inhibitors, we investigated the contribution of W324 to CtBP2's biochemical and physiologic activities utilizing mutational analysis. Indeed, W324 was necessary for CtBP2 self-association, as shown by analytical ultracentrifugation and in vivo cross-linking. Additionally, W324 supported CtBP's association with the transcriptional corepressor CoREST, and was critical for CtBP2 induction of cell motility. Notably, the HIPP derivative 4-chloro-HIPP biochemically and biologically phenocopied mutational inactivation of CtBP2 W324. Our data support further optimization of W318/W324-interacting CtBP dehydrogenase inhibitors that are emerging as a novel class of cancer cell-specific therapeutic.


Assuntos
Oxirredutases do Álcool/química , Oxirredutases do Álcool/genética , Antineoplásicos/farmacologia , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Inibidores Enzimáticos/farmacologia , Polipose Intestinal/tratamento farmacológico , Triptofano/metabolismo , Oxirredutases do Álcool/antagonistas & inibidores , Animais , Antineoplásicos/química , Domínio Catalítico , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Proteínas de Ligação a DNA/antagonistas & inibidores , Inibidores Enzimáticos/química , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HCT116 , Humanos , Hidroxilaminas/química , Hidroxilaminas/farmacologia , Polipose Intestinal/metabolismo , Camundongos , Mutagênese Sítio-Dirigida , Fenilpropionatos/química , Fenilpropionatos/farmacologia , Multimerização Proteica/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
13.
J Biol Chem ; 294(25): 9722-9733, 2019 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-31068415

RESUMO

Bone is a highly metabolic organ that undergoes continuous remodeling to maintain its structural integrity. During development, bones, in particular osteoblasts, rely on glucose uptake. However, the role of glucose metabolism in osteocytes is unknown. Osteocytes are terminally differentiated osteoblasts orchestrating bone modeling and remodeling. In these cells, parathyroid hormone (PTH) suppresses Sost/sclerostin expression (a potent inhibitor of bone formation) by promoting nuclear translocation of class IIa histone deacetylase (HDAC) 4 and 5 and the repression of myocyte enhancer factor 2 (MEF2) type C. Recently, Scriptaid, an HDAC complex co-repressor inhibitor, has been shown to induce MEF2 activation and exercise-like adaptation in mice. In muscles, Scriptaid disrupts the HDAC4/5 co-repressor complex, increases MEF2C function, and promotes cell respiration. We hypothesized that Scriptaid, by affecting HDAC4/5 localization and MEF2C activation, might affect osteocyte functions. Treatment of the osteocytic Ocy454-12H cells with Scriptaid increased metabolic gene expression, cell respiration, and glucose uptake. Similar effects were also seen upon treatment with PTH, suggesting that both Scriptaid and PTH can promote osteocyte metabolism. Similar to PTH, Scriptaid potently suppressed Sost expression. Silencing of HDAC5 in Ocy454-12H cells abolished Sost suppression but not glucose transporter type 4 (Glut4) up-regulation induced by Scriptaid. These results demonstrate that Scriptaid increases osteocyte respiration and glucose uptake by mechanisms independent of HDAC complex inhibition. In osteocytes, Scriptaid, similar to PTH, increases binding of HDAC5 to Mef2c with suppression of Sost but only partially increases receptor activator of NF-κB ligand (Rankl) expression, suggesting a potential bone anabolic effect.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Transportador de Glucose Tipo 4/metabolismo , Inibidores de Histona Desacetilases/farmacologia , Hidroxilaminas/farmacologia , Osteócitos/metabolismo , Hormônio Paratireóideo/farmacologia , Quinolinas/farmacologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Hormônios e Agentes Reguladores de Cálcio/farmacologia , Células Cultivadas , Feminino , Transportador de Glucose Tipo 4/genética , Histona Desacetilases/genética , Histona Desacetilases/metabolismo , Fatores de Transcrição MEF2/genética , Fatores de Transcrição MEF2/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Osteócitos/citologia , Osteócitos/efeitos dos fármacos
14.
J Colloid Interface Sci ; 551: 1-9, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31071490

RESUMO

Ultrasound-responsive chemistry was exploited in manufacture of drug delivery nanoparticulates for pursuit of on-demand ultrasound-stimulated drug release function. In principle, the ultrasound-labile oxyl-alkylhydroxylamine (-oa-) linkage was tailored between the segments of amphiphiles. Consequently, the hydrophobic chemotherapeutic doxorubicin could be readily assembled with the hydrophobic segments of amphiphiles into interior compartments, whereas the hydrophilic segments represented as the external surroundings. Upon ultrasonication, the proposed phase-segregated self-assemblies were determined to be subjected to evident structural rearrangement as a consequence of -oa- cleavage. Simultaneously, the release rate of doxorubicin payloads appeared to accelerate due to the ultrasound-induced structural destabilization, consequently eliciting potent cytotoxic efficacy at the affected cells. Another noteworthy characteristic of the proposed self-assemblies was poly (lactobionamidoethyl methacrylate) (pLAMA) as the hydrophilic components of the amphiphiles, characterized to possess galactosylated residues. In view of the specific affinity of galactosylated residues (and lactosylated residues) to asialoglycoprotein receptors (overexpressed on the surface of intractable hepatocellular carcinoma), the proposed self-assemblies were determined to impart preferential affinities to hepatocellular carcinoma. Together with the strategic ultrasound-stimulated drug release property, our proposed drug delivery system demonstrated appreciably pharmaceutical efficacy on hepatocellular carcinoma.


Assuntos
Antineoplásicos/administração & dosagem , Carcinoma Hepatocelular/tratamento farmacológico , Portadores de Fármacos/química , Hidroxilaminas/química , Neoplasias Hepáticas/tratamento farmacológico , Nanopartículas/química , Ácidos Polimetacrílicos/química , Ondas Ultrassônicas , Sobrevivência Celular/efeitos dos fármacos , Doxorrubicina/administração & dosagem , Liberação Controlada de Fármacos , Galactose/química , Células Hep G2 , Humanos , Interações Hidrofóbicas e Hidrofílicas , Cinética , Polimerização
15.
Int J Mol Sci ; 20(8)2019 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-31010057

RESUMO

The interactions between neuronal, glial, and vascular cells play a key role in regulating blood flow in the retina. In the present study, we examined the role of the interactions between neuronal and glial cells in regulating the retinal vascular tone in rats upon stimulation of retinal neuronal cells by intravitreal injection of N-methyl-d-aspartic acid (NMDA). The retinal vascular response was assessed by measuring the diameter of the retinal arterioles in the in vivo fundus images. Intravitreal injection of NMDA produced retinal vasodilation that was significantly diminished following the pharmacological inhibition of nitric oxide (NO) synthase (nNOS), loss of inner retinal neurons, or intravitreal injection of glial toxins. Immunohistochemistry revealed the expression of nNOS in ganglion and calretinin-positive amacrine cells. Moreover, glial toxins significantly prevented the retinal vasodilator response induced by intravitreal injection of NOR3, an NO donor. Mechanistic analysis revealed that NO enhanced the production of vasodilatory prostanoids and epoxyeicosatrienoic acids in glial cells in a ryanodine receptor type 1-dependent manner, subsequently inducing the retinal vasodilator response. These results suggest that the NO released from stimulated neuronal cells acts as a key messenger in neuron-glia signaling, thereby causing neuronal activity-dependent and glial cell-mediated vasodilation in the retina.


Assuntos
Neuroglia/metabolismo , Neurônios/metabolismo , Vasos Retinianos/metabolismo , Transdução de Sinais , Animais , Gangliosídeos/metabolismo , Hidroxilaminas , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Masculino , Modelos Biológicos , N-Metilaspartato/metabolismo , N-Metilaspartato/farmacologia , Neuroglia/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Óxido Nítrico Sintase Tipo I/metabolismo , Prostaglandinas/metabolismo , Ratos Wistar , Vasos Retinianos/patologia , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Transdução de Sinais/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos
16.
Bioorg Med Chem ; 27(7): 1430-1436, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30792103

RESUMO

Class C ß-lactamases have previously been shown to be efficiently inactivated by O-aryloxycarbonyl hydroxamates. O-Phenoxycarbonyl-N-benzyloxycarbonylhydroxylamine (1) and O-phenoxycarbonyl-N-(R)-[(4-amino-4-carboxy-1-butyl)oxycarbonyl]hydroxylamine (2), for example, were found to be effective inactivators. The present paper describes a structure-activity study of these molecules to better define the important structural elements for high inhibitory activity. The results show that a well-positioned hydrophobic element (which may interact with the Tyr221 residue of the enzyme) and a negatively charged element, e.g. a carboxylate group (which may interact with Arg204), are required for high reactivity with the enzyme. The new compounds were found to inactivate by forming a carbonyl cross-linked enzyme (probably Ser64OCONHLys 315) as for 1 rather than the inert hydroxamoyl derivative observed with 2.


Assuntos
Ácidos Hidroxâmicos/farmacologia , Inibidores de beta-Lactamases/farmacologia , beta-Lactamases/metabolismo , Relação Dose-Resposta a Droga , Enterobacter cloacae/enzimologia , Ácidos Hidroxâmicos/síntese química , Ácidos Hidroxâmicos/química , Hidroxilaminas/síntese química , Hidroxilaminas/química , Hidroxilaminas/farmacologia , Cinética , Estrutura Molecular , Relação Estrutura-Atividade , Inibidores de beta-Lactamases/síntese química , Inibidores de beta-Lactamases/química
17.
Org Lett ; 21(5): 1325-1330, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30762372

RESUMO

The limited scope of DNA-compatible chemistry restricts the types of chemical features that can be incorporated into DNA-encoded libraries (DELs). Here, a method to synthesize DNA-conjugated polycyclic isoxazolidines via a [3 + 2] nitrone-olefin cycloaddition is described. The reaction is compatible with many olefin-containing substrates and diverse N-alkylhydroxylamines. The ability to perform subsequent DNA ligation and PCR amplification was also confirmed. This methodology facilitates the synthesis of DELs containing topographically complex compounds with underexplored chemical features.


Assuntos
Alcenos/química , DNA/química , Óxidos de Nitrogênio/química , Reação de Cicloadição/métodos , Descoberta de Drogas , Hidroxilaminas/química , Estrutura Molecular , Bibliotecas de Moléculas Pequenas/química , Temperatura
18.
Water Res ; 153: 274-283, 2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30735957

RESUMO

This study has demonstrated that hydroxylamine (HA) could greatly enhance Cu nanoparticles (nCu) in activating molecular oxygen and significantly elevate the diclofenac (DCF) degradation rate about two orders of magnitude in neutral circumstances. Effects of several important parameters on the DCF degradation such as nCu loading, HA dosage, pH and reaction temperature were investigated in the nCu/HA/O2 system. Multiple examinations revealed that the reactive Cu(III) species instead of OH• would be predominant in the nCu/HA/O2 system, despite their similar DCF degradation pathways. Based on a HA-enhanced copper cycle depending on the pristine Cu0@Cu(I) (hydro)oxides core-shell structure, the heterogeneous-homogeneous reaction mechanism was proposed. It included solid-liquid interfacial and bulk reactions, e.g. heterogeneous activation of O2 by Cu(I) to produce H2O2 and homogeneous Cu(I)-catalytic generation of Cu(III) from H2O2. Further quantitative investigation of the main reactive species in the cycle revealed that the Cu(I) regeneration instead of the O2 activation would be rate-limited. Besides, nCu could be recycled to effectively degrade DCF in four consecutive cycles in the raw neural nCu/HA/O2 system. It suggested that the nCu/HA/O2 system with a more efficient copper cycle would be a good alternative Fenton-like system in treating neutral recalcitrant organic wastewaters.


Assuntos
Cobre , Nanopartículas , Diclofenaco , Peróxido de Hidrogênio , Hidroxilamina , Hidroxilaminas
19.
Toxins (Basel) ; 11(2)2019 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-30736322

RESUMO

Snakebite with hemotoxic venom continues to be a major source of morbidity and mortality worldwide. Our laboratory has characterized the coagulopathy that occurs in vitro in human plasma via specialized thrombelastographic methods to determine if venoms are predominantly anticoagulant or procoagulant in nature. Further, the exposure of venoms to carbon monoxide (CO) or O-phenylhydroxylamine (PHA) modulate putative heme groups attached to key enzymes has also provided mechanistic insight into the multiple different activities contained in one venom. The present investigation used these techniques to characterize fourteen different venoms obtained from snakes from North, Central, and South America. Further, we review and present previous thrombelastographic-based analyses of eighteen other species from the Americas. Venoms were found to be anticoagulant and procoagulant (thrombin-like activity, thrombin-generating activity). All prospectively assessed venom activities were determined to be heme-modulated except two, wherein both CO and its carrier molecule were found to inhibit activity, while PHA did not affect activity (Bothriechis schlegelii and Crotalus organus abyssus). When divided by continent, North and Central America contained venoms with mostly anticoagulant activities, several thrombin-like activities, with only two thrombin-generating activity containing venoms. In contrast, most venoms with thrombin-generating activity were located in South America, derived from Bothrops species. In conclusion, the kinetomic profiles of venoms obtained from thirty-two Pan-American Pit Viper species are presented. It is anticipated that this approach will be utilized to identify clinically relevant hemotoxic venom enzymatic activity and assess the efficacy of locally delivered CO or systemically administered antivenoms.


Assuntos
Anticoagulantes/farmacologia , Coagulação Sanguínea/efeitos dos fármacos , Coagulantes/farmacologia , Venenos de Crotalídeos/farmacologia , Crotalinae , Animais , Anticoagulantes/química , América Central , Coagulantes/química , Venenos de Crotalídeos/química , Humanos , Hidroxilaminas/farmacologia , Cinética , América do Norte , Compostos Organometálicos/farmacologia , Plasma/efeitos dos fármacos , Plasma/fisiologia , América do Sul , Tromboelastografia
20.
Nitric Oxide ; 84: 22-29, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30630055

RESUMO

Garlic has been demonstrated to exert protective effects against oxidative damage using numerous experimental models. The antioxidant effects of garlic are associated with the activation of Nrf2-dependent gene expression. S-1-Propenylcysteine (S1PC) and S-allylcysteine (SAC) are two predominant sulfur amino acids present in aged garlic extract; however, the exact roles of these amino acids within the Keap1/Nrf2 system remain unknown. We hypothesized that sulfur-containing amino acids derived from garlic could activate Nrf2 in the presence of nitric oxide (NO). Neither S1PC nor SAC affected gene expression of either heme oxygenase-1 (HMOX1) or the glutamate-cysteine ligase modifier subunit (GCLM) in human umbilical vein endothelial cells (HUVECs) or human aorta endothelial cells (HAECs). Interestingly, S1PC augmented expression levels induced by nitric oxide donors (NO-donors) such as NOR3 and GSNO. NO-donors were found to induce nuclear accumulation of NRF2 and activation of the eIF2α/ATF4 pathway, whereas S1PC did not further amplify the NO-induced effects on NRF2 or eIF2α/ATF4. Additionally, NO-donors induced the degradation of BTB domain and CNC homolog 1 (BACH1), a transcriptional repressor that can compete with NRF2. In addition, S1PC enhanced BACH1 downregulation within the nucleus. Pretreatment with deferoxamine, an inhibitor of heme synthesis, upregulated BACH1 protein levels and abolished the effect of NO-donors and S1PC on HMOX1 expression. The above results indicate that S1PC could modulate antioxidant gene expression via the NO/heme/BACH1 signaling pathway, thereby suggesting that S1PC-induced degradation of BACH1 may provide a basis for therapeutic applications.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Cisteína/análogos & derivados , Cisteína/farmacologia , Heme Oxigenase-1/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Óxido Nítrico/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/genética , Regulação para Baixo , Glutamato-Cisteína Ligase/metabolismo , Heme Oxigenase-1/genética , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Hidroxilaminas/farmacologia , Fator 2 Relacionado a NF-E2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Regulação para Cima
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