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1.
Chem Biol Interact ; 329: 109222, 2020 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-32771325

RESUMO

Extensive application of methylene blue (MB) for therapeutic and diagnostic purposes, and reports for unwanted side effects, demand better understanding of the mechanisms of biological action of this thiazine dye. Because MB is redox-active, its biological activities have been attributed to transfer of electrons, generation of reactive oxygen species, and antioxidant action. Results of this study show that MB is more toxic to a superoxide dismutase-deficient Escherichia coli mutant than to its SOD-proficient parent, which indicates that superoxide anion radical is involved. Incubation of E. coli with MB induced the enzymes fumarase C, SOD, nitroreductase A, and glucose-6-phosphate dehydrogenase, all controlled by the soxRS regulon. Induction of these enzymes was prevented by blocking protein synthesis with chloramphenicol and was not observed when soxRS-negative mutants were incubated with MB. These results show that MB is capable of inducing the soxRS regulon of E. coli, which plays a key role in protecting bacteria against oxidative stress and redox-cycling compounds. Irrespective of the abundance of heme-containing proteins in living cells, which are preferred acceptors of electrons from the reduced form of MB, reduction of oxygen to superoxide radical still takes place. Induction of the soxRS regulon suggests that in humans, beneficial effects of MB could be attributed to activation of redox-sensitive transcription factors like Nrf2 and FoxO. If defense systems are compromised or genes coding for protective proteins are not induced, MB would have deleterious effects.


Assuntos
Proteínas de Bactérias/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Azul de Metileno/farmacologia , Regulon/efeitos dos fármacos , Transativadores/metabolismo , Fatores de Transcrição/metabolismo , Proteínas de Bactérias/genética , Cloranfenicol/farmacologia , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Fumarato Hidratase/genética , Fumarato Hidratase/metabolismo , Glucosefosfato Desidrogenase/metabolismo , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Biossíntese de Proteínas/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo , Transativadores/genética , Fatores de Transcrição/genética
2.
Toxicol Lett ; 332: 118-129, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32659471

RESUMO

Silver-based antimicrobials are widely used topically to treat infections associated with multi-drug resistant (MDR) pathogens. Expanding this topical use to aerosols to treat lung infections requires understanding and preventing silver toxicity in the respiratory tract. A key mechanism resulting in silver-induced toxicity is the production of reactive oxygen species (ROS). In this study, we have verified ROS generation in silver-treated bronchial epithelial cells prompting evaluation of three antioxidants, N-acetyl cysteine (NAC), ascorbic acid, and melatonin, to identify potential prophylactic agents. Among them, NAC was the only candidate that abrogated the ROS generation in response to silver acetate exposure resulting in the rescue of these cells from silver-associated toxicity. Further, this protective effect directly translated to preservation of metabolic activity, as demonstrated by the normal levels of citric acid cycle metabolites in NAC-pretreated silver acetate-exposed cells. Because the citric acid cycle remained functional, silver-exposed cells pre-incubated with NAC demonstrated significantly higher levels of adenosine triphosphate levels compared with NAC-free controls. Moreover, we found that this prodigious capacity of NAC to rescue silver acetate-exposed cells was due not only to its antioxidant activity, but also to its ability to directly bind silver. Despite binding to silver, NAC did not alter the antimicrobial activity of silver acetate.


Assuntos
Acetilcisteína/farmacologia , Antibacterianos/farmacologia , Depuradores de Radicais Livres/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Prata/farmacologia , Prata/toxicidade , Acetatos/farmacologia , Trifosfato de Adenosina/metabolismo , Ácido Ascórbico/farmacologia , Linhagem Celular , Cromatografia Gasosa-Espectrometria de Massas , Glutationa/metabolismo , Humanos , Melatonina/farmacologia , Testes de Sensibilidade Microbiana , Compostos de Prata/farmacologia , Superóxidos/metabolismo
3.
Postepy Biochem ; 66(2): 91-99, 2020 06 27.
Artigo em Polonês | MEDLINE | ID: mdl-32700506

RESUMO

Cytochromes bc1 and c b6f are part of respiratory or photosynthetic machinery. The main role of these enzymes is to build proton motive force across the bioenergetic membranes by coupling the proton translocations with electron transfer from the pool of membrane-soluble quinones to water-soluble redox proteins. Despite many years of research, the mechanism of quinol oxidation is not fully understood. It is assumed that unstable form of a partially oxidized quinol ­ semiquinone is an intermediate state of this process and that it is also a potential electron donor in the side reaction of superoxide generation. This semiquinone has remained experimentally elusive over years but recently a semiquinone interacting with the reduced iron-sulfur cluster was identified as a new state of the enzyme. The results indicate that semiquinone coupled to the iron-sulfur cluster is most probably an additional state that can prevent side reactions, including superoxide generation.


Assuntos
Benzoquinonas/química , Benzoquinonas/metabolismo , Elétrons , Citocromos/metabolismo , Transporte de Elétrons , Oxirredução , Superóxidos/metabolismo
4.
Food Chem ; 332: 127409, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32615388

RESUMO

This work reports a new method to evaluate the antioxidant capacity of infusions and beverages, based on superoxide radicals. Radicals produced by the enzymatic reaction between acetylcholinesterase and hypoxanthine oxidized antioxidant molecules present in commercially available samples or standard solutions, which was monitored by means of cyclic voltammetry using a carbon paste electrode. The Trolox equivalent antioxidant capacity (TEAC) of red wine, coffee and green tea determined using this method were: (1.20 ± 0.06), (0.90 ± 0.02), and (0.65 ± 0.02), respectively. This method suggested TEACred wine > TEACcoffee > TEACgreen tea, which is the same as DPPH, spectrophotometric method. However, the electrochemical one proposed here is rapid and simple.


Assuntos
Antioxidantes/química , Bebidas/análise , Técnicas Eletroquímicas/métodos , Superóxidos/química , Antioxidantes/metabolismo , Café/química , Eletrodos , Concentração de Íons de Hidrogênio , Hipoxantina/química , Hipoxantina/metabolismo , Oxirredução , Superóxidos/metabolismo , Chá/química , Vinho/análise , Xantina Oxidase/metabolismo
5.
Chemosphere ; 259: 127258, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32585458

RESUMO

This is the first study to investigate the reduction mechanism of Tl (III) to Tl(I) in the presence of plants, especially rice. Smaller plant density could effectively reduce the content of organic acids in the hydroponic system to keep the stability of Tl(III). As the plant density was reduced from 40 seedlings to 10 seedlings in 100 mL Tl(III) solution, the content of oxalate was declined to one-third of the original, and the ratio of Tl(III)/total Tl was increased from 39.6% to 81.0% in the first 2 h treatment. Then the differences in antioxidant capacity of rice exposed to the two Tl species were studied. The contents of malondialdehyde (MDA), hydrogen peroxide (H2O2) and superoxide anion (O2˙-) of rice roots exposed to Tl(III) were all higher than those to Tl(I). Meanwhile, the catalase (CAT) activity was significantly depressed and peroxidase (POD) was increased by Tl(III), whereas superoxide dismutase (SOD) showed a rise in both Tl(I) and Tl(III) with no significant difference between them. The expression of metallothionein gene OsMT1a to Tl(I) was upregulated to 255.5 times of Tl(III) though OsMT2c was downregulated to 0.39 times of Tl(III). Overall, the different responses in metallothionein gene expression and antioxidative enzyme activation might result in more ROS accumulation to rice roots by Tl(III) treatment than those by Tl(I).


Assuntos
Metalotioneína/genética , Oryza/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Tálio/toxicidade , Antioxidantes/metabolismo , Catalase/metabolismo , Peróxido de Hidrogênio/metabolismo , Hidroponia , Malondialdeído/metabolismo , Metalotioneína/metabolismo , Oryza/genética , Oryza/metabolismo , Peroxidase/metabolismo , Peroxidases/metabolismo , Raízes de Plantas/metabolismo , Plântula/metabolismo , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo
6.
PLoS One ; 15(6): e0234435, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32574221

RESUMO

This study was designed to investigate the antioxidant properties of the extracts and subfractions of various polarities from Clerodendrum cyrtophyllum Turcz leaves and the related phenolic compound profiles. The ethyl acetate fraction (EAF) showed the most potent radical-scavenging activity for DPPH radicals, ABTS radicals, and superoxide anion (O2·-) radicals as well as the highest reducing power of the fractions tested; the n-butyl alcohol fraction (BAF) was the most effective in scavenging hydroxyl radical (OH·), and the dichloromethane fraction (DMF) exhibited the highest ferrous ion chelating activity. Twelve phenolic components were identified from the EAF of C. cyrtophyllum. Additionally, acteoside (1) was found to be a major component (0.803 g, 0.54%) and show DPPH and ABTS radical scavenging activities with IC50 values of 79.65±3.4 and 23.00±1.5 µg/ml, indicating it is principally responsible for the significant total antioxidant effect of C. cyrtophyllum. Our work offers a theoretical basis for further utilization of C. cyrtophyllum as a potential source of natural, green antioxidants derived from plants.


Assuntos
Antioxidantes/farmacologia , Clerodendrum/química , Glucosídeos/farmacologia , Fenóis/farmacologia , Extratos Vegetais/farmacologia , Antioxidantes/análise , Antioxidantes/isolamento & purificação , Glucosídeos/análise , Glucosídeos/isolamento & purificação , Radical Hidroxila/metabolismo , Fenóis/análise , Fenóis/isolamento & purificação , Extratos Vegetais/análise , Extratos Vegetais/isolamento & purificação , Folhas de Planta/química , Superóxidos/metabolismo
7.
Nat Commun ; 11(1): 2738, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32483131

RESUMO

Almost half of all enzymes utilize a metal cofactor. However, the features that dictate the metal utilized by metalloenzymes are poorly understood, limiting our ability to manipulate these enzymes for industrial and health-associated applications. The ubiquitous iron/manganese superoxide dismutase (SOD) family exemplifies this deficit, as the specific metal used by any family member cannot be predicted. Biochemical, structural and paramagnetic analysis of two evolutionarily related SODs with different metal specificity produced by the pathogenic bacterium Staphylococcus aureus identifies two positions that control metal specificity. These residues make no direct contacts with the metal-coordinating ligands but control the metal's redox properties, demonstrating that subtle architectural changes can dramatically alter metal utilization. Introducing these mutations into S. aureus alters the ability of the bacterium to resist superoxide stress when metal starved by the host, revealing that small changes in metal-dependent activity can drive the evolution of metalloenzymes with new cofactor specificity.


Assuntos
Proteínas de Bactérias/metabolismo , Ferro/metabolismo , Manganês/metabolismo , Metaloproteínas/metabolismo , Staphylococcus aureus/enzimologia , Superóxido Dismutase/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Domínio Catalítico , Evolução Molecular , Ferro/química , Isoenzimas/classificação , Isoenzimas/genética , Isoenzimas/metabolismo , Manganês/química , Metaloproteínas/química , Metaloproteínas/genética , Mutação , Oxirredução , Filogenia , Homologia de Sequência de Aminoácidos , Staphylococcus aureus/genética , Superóxido Dismutase/química , Superóxido Dismutase/genética , Superóxidos/metabolismo
8.
Am J Physiol Heart Circ Physiol ; 319(1): H51-H65, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32412791

RESUMO

Although there is a strong association between cigarette smoking exposure (CSE) and vascular endothelial dysfunction (VED), the underlying mechanisms by which CSE triggers VED remain unclear. Therefore, studies were performed to define these mechanisms using a chronic mouse model of cigarette smoking (CS)-induced cardiovascular disease mirroring that in humans. C57BL/6 male mice were subjected to CSE for up to 48 wk. CSE impaired acetylcholine (ACh)-induced relaxation of aortic and mesenteric segments and triggered hypertension, with mean arterial blood pressure at 32 and 48 wk of exposure of 122 ± 6 and 135 ± 5 mmHg compared with 99 ± 4 and 102 ± 6 mmHg, respectively, in air-exposed mice. CSE led to monocyte activation with superoxide generation in blood exiting the pulmonary circulation. Macrophage infiltration with concomitant increase in NADPH oxidase subunits p22phox and gp91phox was seen in aortas of CS-exposed mice at 16 wk, with further increase out to 48 wk. Associated with this, increased superoxide production was detected that decreased with Nox inhibition. Tetrahydrobiopterin was progressively depleted in CS-exposed mice but not in air-exposed controls, resulting in endothelial nitric oxide synthase (eNOS) uncoupling and secondary superoxide generation. CSE led to a time-dependent decrease in eNOS and Akt expression and phosphorylation. Overall, CSE induces vascular monocyte infiltration with increased NADPH oxidase-mediated reactive oxygen species generation and depletes the eNOS cofactor tetrahydrobiopterin, uncoupling eNOS and triggering a vicious cycle of oxidative stress with VED and hypertension. Our study provides important insights toward understanding the process by which smoking contributes to the genesis of cardiovascular disease and identifies biomarkers predictive of disease.NEW & NOTEWORTHY In a chronic model of smoking-induced cardiovascular disease, we define underlying mechanisms of smoking-induced vascular endothelial dysfunction (VED). Smoking exposure triggered VED and hypertension and led to vascular macrophage infiltration with concomitant increase in superoxide and NADPH oxidase levels as early as 16 wk of exposure. This oxidative stress was accompanied by tetrahydrobiopterin depletion, resulting in endothelial nitric oxide synthase uncoupling with further superoxide generation triggering a vicious cycle of oxidative stress and VED.


Assuntos
Endotélio Vascular/metabolismo , Leucócitos/metabolismo , Estresse Oxidativo , Lesão por Inalação de Fumaça/metabolismo , Poluição por Fumaça de Tabaco/efeitos adversos , Vasodilatação , Animais , Aorta/metabolismo , Aorta/fisiopatologia , Pressão Sanguínea , Endotélio Vascular/fisiopatologia , Masculino , Artérias Mesentéricas/metabolismo , Artérias Mesentéricas/fisiopatologia , Camundongos , Camundongos Endogâmicos C57BL , NADPH Oxidases/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Lesão por Inalação de Fumaça/etiologia , Lesão por Inalação de Fumaça/fisiopatologia , Superóxidos/metabolismo
9.
Oncology ; 98(7): 478-486, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32434184

RESUMO

INTRODUCTION: Metastatic breast cancer has poor prognosis due to limited therapeutic options. Protein kinase dysregulations have a major role in breast cancer progression and metastasis. In this study, we investigated the anti-cancer activity of sorafenib, a multikinase inhibitor, which targets receptor tyrosine kinases in breast cancer. Although treatment with sorafenib has increased the patient survival and inhibited metastatic migration in hepatocellular carcinoma, its role in breast cancer migration, metastasis, and intracellular signaling modulation is unknown. METHODS: Breast cancer cell lines MCF7 and MDA-MB-231 were treated with sorafenib and its effect on proliferation, migration, invasion and gene expression was analyzed. RESULTS: We found that sorafenib has an anti-proliferative and cytotoxic effect on breast cancer cells. Importantly, sorafenib inhibited the migration and invasion of breast cancer cells in vitro. Mechanistically, sorafenib increased mitochondrial superoxide production, suppressed breast cancer stem cell self-renewal, inhibited epithelial mesenchymal transition and ERK signaling. CONCLUSION: Thus, sorafenib has anti-cancer activity against breast cancer cells and could improve the survival of breast cancer patients by inhibiting their invasive and metastatic properties.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sorafenibe/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Células MCF-7 , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Invasividade Neoplásica/prevenção & controle , Superóxidos/metabolismo
10.
Anticancer Res ; 40(4): 1963-1972, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32234885

RESUMO

BACKGROUND/AIM: The menadione/ascorbate (M/A) combination has attracted attention due to the unusual ability of pro-vitamin/vitamin combination to kill cancer cells without affecting the viability of normal cells. The aim of this study was to elucidate the role of M/A in targeting cancerous mitochondria. MATERIALS AND METHODS: Several cancer and normal cell lines of the same origin were used. Cells were treated with different concentrations of M/A for 24 h. The cell viability, mitochondrial superoxide, mitochondrial membrane potential, and succinate were analyzed using conventional analytical tests. RESULTS: M/A exhibited a highly specific suppression on cancer cell growth and viability, without adversely affecting the viability of normal cells at concentrations attainable by oral or parenteral administration in vivo. This effect was accompanied by: (i) an extremely high production of mitochondrial superoxide in cancer cells, but not in normal cells; (ii) a significant dose-dependent depolarization of mitochondrial membrane and depletion of oncometabolite succinate in cancer cells. CONCLUSION: The anticancer effect of M/A is related to the induction of severe mitochondrial oxidative stress in cancer cells only. Thus, M/A has a potential to increase the sensitivity and vulnerability of cancer cells to conventional anticancer therapy and immune system.


Assuntos
Ácido Ascórbico/farmacologia , Mitocôndrias/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Vitamina K 3/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/patologia , Neoplasias/genética , Neoplasias/patologia , Estresse Oxidativo/efeitos dos fármacos , Superóxido Dismutase/genética , Superóxidos/metabolismo
11.
Mar Drugs ; 18(4)2020 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-32331404

RESUMO

Further chemical investigation of the EtOAc extract of the soft coral Lobophytum varium resulted in the discovery of eleven new diterpenoids lobovarols F-P (1-11) of lobane- and prenyleudesmane-types, along with two known metabolites (12 and 13). The structures of the new metabolites were established by spectroscopic analyses, including 2D NMR experiments. The absolute configuration of 1 was determined using Mosher's method. The complete assignment of 1H and 13C NMR spectroscopic data of 12 and 13 and the identification of pyran-derived moieties in the prenyleudesmanes were reported for the first time. Anti-inflammatory activities of the isolated compounds in suppressing elastase release and superoxide anion generation in human neutrophils were disclosed for 1, 2, 4, 12, and 13. A stereospecific biosynthesis for lobanes and prenyleudesmanes from the related prenylgermacranes could explain the coexistence of lobanes and prenylgermacranes in L. varium.


Assuntos
Antozoários/química , Anti-Inflamatórios/isolamento & purificação , Diterpenos/isolamento & purificação , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Diterpenos/química , Diterpenos/farmacologia , Humanos , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Elastase Pancreática/metabolismo , Estereoisomerismo , Superóxidos/metabolismo
12.
Toxicol Lett ; 327: 19-31, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32234357

RESUMO

Traditional Chinese Medicines (TCMs)-containing aconitine are popular and indispensable home remedies in Asia for thousands of years due to its excellent pharmaceutical effects. Accumulating evidence has identified that repeated-dose of aconitine could cause polymorphic ventricular arrhythmias. However, underlying molecular mechanisms are still not fully understood. Hence, the present study firstly investigated the potential role of Notch1 signaling in aconitine-induced cardiotoxicity, aiming to elaborate possible molecular mechanisms involved in aconitine triggered ventricular arrhythmias. Our results showed that aconitine increased Notch1 signaling and downstream KDM5A expression in human and rat cardiomyocytes at non-detectable cytotoxic doses. Furthermore, aconitine promoted the formation of a new regulatory complex containing NICD and KDM5A in a CK2αHI regime, which then targeted to HCN4 promoter and induced re-expression of HCN4 in mature cardiomyocytes. Ultimately, HCN4-mediated If current contributed to aconitine-caused alterations in beating rate of rat cardiomyocytes. All changes aforementioned were significantly ameliorated by Notch1 inhibitor, suggesting that Notch1-mediated epigenetic regulation of HCN4 contributes to aconitine-induced ventricular myocardial dysrhythmia. Thus, our findings provide a novel toxic mechanism and position Notch1/NICD/KDM5A/HCN4 toxicity pathway as a potential target for the treatments of repeated-dose of medicine containing aconitine induced ventricular arrhythmias.


Assuntos
Aconitina/farmacologia , Arritmias Cardíacas/induzido quimicamente , Ventrículos do Coração/efeitos dos fármacos , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/metabolismo , Canais de Potássio/metabolismo , Receptor Notch1/metabolismo , Animais , Animais Recém-Nascidos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Histonas , Humanos , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/genética , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Canais de Potássio/genética , Ratos , Receptor Notch1/genética , Superóxidos/metabolismo
13.
Ecotoxicol Environ Saf ; 196: 110534, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32247242

RESUMO

This study aimed to further understand the toxicity of high concentrations of nitrogen dioxide (NO2) to plants, especially to plant photosynthesis. Tobacco plants in the six-leaf stage were exposed to 16.0 µL L-1 NO2 to determine the activities of photosystem II (PSII) and photosystem I (PSI) reaction centers, the blocking site of PSII electron transport, the degree of membrane peroxidation and the relative expression of PsbA, PsbO and PsaA genes in the third fully expanded leaves by using gas exchange and chlorophyll fluorescence techniques, biochemical and RT-PCR analysis. The results showed that 16.0 µL L-1 NO2 caused necrotic lesions to form on leaves and significantly increased the generation rate of superoxide anions (O2-) and the content of peroxynitrite (ONOO-) in leaves of tobacco seedling, leading to damage to cell membrane, chlorophyll content and net photosynthetic rate reduction, and photosynthetic apparatus destruction. Fumigation with 16.0 µL L-1 NO2 decreased the activity of PSII reaction center and oxygen evolution complex, and the relative expression of PabA in leaves of tobacco seedlings to inhibit the electron transport from the donor side to the receptor side of PSII, especially blocking the electron transport from QA to QB on the receptor side. The activity of the PSI reaction center and the relative expression of PsaA decreased, weakening the ability to accept electrons and inhibiting the electron transfer from PSII to PSI, which further increased the damage of PSII of tobacco seedling leaves caused by 16.0 µL L-1 NO2. Therefore, 16.0 µL L-1 NO2 leaded to the accumulation of O2- and ONOO-, which damaged the cell membrane and thylakoid membrane, inhibit the electron transport, and destroyed the photosynthetic apparatus in leaves of tobacco seedlings. The results from this study emphasized the importance of reducing the NO2 concentration in the atmosphere.


Assuntos
Dióxido de Nitrogênio/toxicidade , Ácido Peroxinitroso/metabolismo , Fotossíntese/efeitos dos fármacos , Superóxidos/metabolismo , Tabaco/efeitos dos fármacos , Poluentes Atmosféricos/toxicidade , Transporte de Elétrons/efeitos dos fármacos , Complexo de Proteína do Fotossistema I/efeitos dos fármacos , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/efeitos dos fármacos , Complexo de Proteína do Fotossistema II/metabolismo , Plântula/efeitos dos fármacos , Plântula/metabolismo , Tabaco/metabolismo
14.
Int J Nanomedicine ; 15: 1939-1950, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32256070

RESUMO

Introduction: Chronic trauma repair is an important issue affecting people's healthy lives. Thermo-sensitive hydrogel is injectable in situ and can be used to treat large-area wounds. In addition, antioxidants play important roles in promoting wound repair. Methods: The purpose of this research was to prepare a novel thermo-sensitive hydrogel-poly(N-isopropyl-acrylamide)/poly(γ-glutamic acid) (PP) loaded with superoxide dismutase (SOD) to improve the effect for trauma treatment. The micromorphology of the hydrogel was observed by scanning electron microscope and the physical properties were measured. The biocompatibility of hydrogel was evaluated by MTT experiment, and the effect of hydrogel on skin wound healing was evaluated by in vivo histological staining. Results: Gelling behavior and differential scanning calorimeter outcomes showed that the PP hydrogels possessed thermo-sensitivity at physiological temperature and the phase transformation temperature was 28.2°C. The high swelling rate and good water retention were conducive to wound healing. The activity of SOD in vitro was up to 85% at 10 h, which was advantageous to eliminate the superoxide anion. MTT assay revealed that this hydrogel possessed good biocompatibility. Dressings of PP loaded with SOD (SOD-PP) had a higher wound closure rate than other treatments in vivo in diabetic rat model. Discussion: The SOD-PP thermo-sensitive hydrogels can effectively promote wound healing and have good application prospects for wound repair.


Assuntos
Bandagens , Hidrogéis/química , Hidrogéis/farmacologia , Superóxido Dismutase/administração & dosagem , Superóxido Dismutase/farmacologia , Cicatrização/efeitos dos fármacos , Resinas Acrílicas/química , Animais , Materiais Biocompatíveis/química , Diabetes Mellitus Experimental/fisiopatologia , Masculino , Teste de Materiais , Ácido Poliglutâmico/química , Polímeros/química , Ratos Sprague-Dawley , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo , Temperatura
15.
Nat Commun ; 11(1): 1735, 2020 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-32269223

RESUMO

The therapeutic effect of reactive oxygen species (ROS)-involved cancer therapies is significantly limited by shortage of oxy-substrates, such as hypoxia in photodynamic therapy (PDT) and insufficient hydrogen peroxide (H2O2) in chemodynamic therapy (CDT). Here, we report a H2O2/O2 self-supplying nanoagent, (MSNs@CaO2-ICG)@LA, which consists of manganese silicate (MSN)-supported calcium peroxide (CaO2) and indocyanine green (ICG) with further surface modification of phase-change material lauric acid (LA). Under laser irradiation, ICG simultaneously generates singlet oxygen and emits heat to melt the LA. The exposed CaO2 reacts with water to produce O2 and H2O2 for hypoxia-relieved ICG-mediated PDT and H2O2-supplying MSN-based CDT, acting as an open source strategy for ROS production. Additionally, the MSNs-induced glutathione depletion protects ROS from scavenging, termed reduce expenditure. This open source and reduce expenditure strategy is effective in inhibiting tumor growth both in vitro and in vivo, and significantly improves ROS generation efficiency from multi-level for ROS-involved cancer therapies.


Assuntos
Tratamento Farmacológico , Fotoquimioterapia , Espécies Reativas de Oxigênio/metabolismo , Animais , Circulação Sanguínea , Compostos de Cálcio/química , Linhagem Celular Tumoral , Sobrevivência Celular , Sinergismo Farmacológico , Feminino , Humanos , Peróxido de Hidrogênio/metabolismo , Verde de Indocianina/química , Ácidos Láuricos/sangue , Ácidos Láuricos/química , Imagem por Ressonância Magnética , Manganês/química , Camundongos Endogâmicos BALB C , Nanopartículas/química , Nanopartículas/ultraestrutura , Óxidos/química , Silicatos/química , Superóxidos/metabolismo , Distribuição Tecidual
16.
J Neurosci ; 40(15): 3119-3129, 2020 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-32144179

RESUMO

Mitochondrial fission catalyzed by dynamin-related protein 1 (Drp1) is necessary for mitochondrial biogenesis and maintenance of healthy mitochondria. However, excessive fission has been associated with multiple neurodegenerative disorders, and we recently reported that mice with smaller mitochondria are sensitized to ischemic stroke injury. Although pharmacological Drp1 inhibition has been put forward as neuroprotective, the specificity and mechanism of the inhibitor used is controversial. Here, we provide genetic evidence that Drp1 inhibition is neuroprotective. Drp1 is activated by dephosphorylation of an inhibitory phosphorylation site, Ser637. We identify Bß2, a mitochondria-localized protein phosphatase 2A (PP2A) regulatory subunit, as a neuron-specific Drp1 activator in vivo Bß2 KO mice of both sexes display elongated mitochondria in neurons and are protected from cerebral ischemic injury. Functionally, deletion of Bß2 and maintained Drp1 Ser637 phosphorylation improved mitochondrial respiratory capacity, Ca2+ homeostasis, and attenuated superoxide production in response to ischemia and excitotoxicity in vitro and ex vivo Last, deletion of Bß2 rescued excessive stroke damage associated with dephosphorylation of Drp1 S637 and mitochondrial fission. These results indicate that the state of mitochondrial connectivity and PP2A/Bß2-mediated dephosphorylation of Drp1 play a critical role in determining the severity of cerebral ischemic injury. Therefore, Bß2 may represent a target for prophylactic neuroprotective therapy in populations at high risk of stroke.SIGNIFICANCE STATEMENT With recent advances in clinical practice including mechanical thrombectomy up to 24 h after the ischemic event, there is resurgent interest in neuroprotective stroke therapies. In this study, we demonstrate reduced stroke damage in the brain of mice lacking the Bß2 regulatory subunit of protein phosphatase 2A, which we have shown previously acts as a positive regulator of the mitochondrial fission enzyme dynamin-related protein 1 (Drp1). Importantly, we provide evidence that deletion of Bß2 can rescue excessive ischemic damage in mice lacking the mitochondrial PKA scaffold AKAP1, apparently via opposing effects on Drp1 S637 phosphorylation. These results highlight reversible phosphorylation in bidirectional regulation of Drp1 activity and identify Bß2 as a potential pharmacological target to protect the brain from stroke injury.


Assuntos
Isquemia Encefálica/genética , Isquemia Encefálica/prevenção & controle , Dinaminas/genética , Neurônios/metabolismo , Animais , Cálcio/metabolismo , Dinaminas/metabolismo , Feminino , Homeostase , Infarto da Artéria Cerebral Média/genética , Infarto da Artéria Cerebral Média/patologia , Masculino , Camundongos , Camundongos Knockout , Mitocôndrias/metabolismo , Fosforilação , Cultura Primária de Células , Proteína Fosfatase 2/genética , Acidente Vascular Cerebral/patologia , Acidente Vascular Cerebral/prevenção & controle , Superóxidos/metabolismo
17.
PLoS One ; 15(3): e0230514, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32187237

RESUMO

Several pathological conditions predict the use of glucocorticoids for the management of the inflammatory response; however, chronic or high dose glucocorticoid treatment is associated with hyperglycemia, hyperlipidemia, and insulin resistance and can be considered a risk factor for cardiovascular disease. Therefore, we investigated the mechanisms involved in the vascular responsiveness and inflammatory profile of mesenteric arteries of rats treated with high doses of glucocorticoids. Wistar rats were divided into a control (CO) group and a dexamethasone (DEX) group, that received dexamethasone for 7 days (2mg/kg/day, i.p.). Blood samples were used to assess the lipid profile and insulin tolerance. Vascular reactivity to Phenylephrine (Phe) and insulin, and O2•-production were evaluated. The intracellular insulin signaling pathway PI3K/AKT/eNOS and MAPK/ET-1 were investigated. Regarding the vascular inflammatory profile, TNF-α, IL-6, IL-1ß and IL-18 were assessed. Dexamethasone-treated rats had decreased insulin tolerance test and endothelium-dependent vasodilation induced by insulin. eNOS inhibition caused vasoconstriction in the DEX group, which was abolished by the ET-A antagonist. Insulin-mediated relaxation in the DEX group was restored in the presence of the O2.- scavenger TIRON. Nevertheless, in the DEX group there was an increase in Phe-induced vasoconstriction. In addition, the intracellular insulin signaling pathway PI3K/AKT/eNOS was impaired, decreasing NO bioavailability. Regarding superoxide anion generation, there was an increase in the DEX group, and all measured proinflammatory cytokines were also augmented in the DEX group. In addition, the DEX-group presented an increase in low-density lipoprotein cholesterol (LDL-c) and total cholesterol (TC) and reduced high-density lipoprotein cholesterol (HDL-c) levels. In summary, treatment with high doses of dexamethasone promoted changes in insulin-induced vasodilation, through the reduction of NO bioavailability and an increase in vasoconstriction via ET-1 associated with generation of O2•- and proinflammatory cytokines.


Assuntos
Glucocorticoides/farmacologia , Insulina/farmacologia , Artérias Mesentéricas/efeitos dos fármacos , Artérias Mesentéricas/metabolismo , Vasodilatação/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Glucocorticoides/administração & dosagem , Insulina/administração & dosagem , Interleucina-18/metabolismo , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Masculino , Óxido Nítrico Sintase Tipo III/metabolismo , Óxidos de Nitrogênio/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos , Superóxidos/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
18.
Artigo em Inglês | MEDLINE | ID: mdl-32178576

RESUMO

The objective of present study was to investigate in vitro protective potential of resveratrol in TM3 Leydig cells with induced oxidative stress using hydrogen peroxide (H2O2). Leydig cells experiencing oxidative stress exhibit reduced activities in androgens production, and become hypofunctional with age, which is also related to growing oxidative stress, while resveratrol has received growing attention as a cytoprotective agent. TM3 mouse Leydig cells were cultivated during 24 h in the presence of resveratrol (5, 10, 25, 50 and 100 µM) alone, or in combination with H2O2 (300/600 µM) to induce oxidative stress. Mitochondrial activity was evaluated using MTT test, triple assay was used in order to assess cell viability parameters, intracellular generation of superoxide was determined by the nitroblue-tetrazolium assay, and quantification of steroid hormones was performed by the enzyme- linked immunosorbent assay. Resveratrol alone treatment led to the most significantly improved values of all tested parameters in the cells of experimental group with addition of 10 µM of resveratrol in comparison to the control group. In the case of cells with induced oxidative stress (300 µM H2O2) resveratrol administration resulted in significantly increased (P < 0.05) metabolic activity, as well as cell membrane integrity at concentration 10 µM. Significantly improved (P < 0.001) lysosomal activity showed cells treated with 5 and 10 µM of resveratrol, and the level of both measured hormones was significantly higher (P < 0.05) in cells supplemented with 10 µM of resveratrol. Significant decline of superoxide radical production was observed in all experimental groups in comparison to the control exposed to H2O2 alone. With respect to cells exposed to higher concentration of H2O2 (600 µM), results showed positive effect of resveratrol only in biosynthesis of both androgens with significant increased values in experimental group treated with 5 µM (P < 0.05) and 10 µM (P < 0.01) of resveratrol, in addition, in the case of testosterone we recorded significant higher (P < 0.05) values in cells with addition of 25 and 50 µM resveratrol when compared to H2O2 control. More specific and systematic research focused especially on androgen biosynthesis is necessary related to the biological activity of resveratrol in male reproductive system due to inconsistent results of studies.


Assuntos
Peróxido de Hidrogênio/toxicidade , Células Intersticiais do Testículo/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Resveratrol/farmacologia , Animais , Antioxidantes/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Suplementos Nutricionais , Relação Dose-Resposta a Droga , Células Intersticiais do Testículo/metabolismo , Masculino , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Superóxidos/metabolismo , Testosterona/biossíntese
19.
Clin Sci (Lond) ; 134(7): 727-746, 2020 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-32202295

RESUMO

We previously identified genomic instability as a causative factor for vascular aging. In the present study, we determined which vascular aging outcomes are due to local endothelial DNA damage, which was accomplished by genetic removal of ERCC1 (excision repair cross-complementation group 1) DNA repair in mice (EC-knockout (EC-KO) mice). EC-KO showed a progressive decrease in microvascular dilation of the skin, increased microvascular leakage in the kidney, decreased lung perfusion, and increased aortic stiffness compared with wild-type (WT). EC-KO showed expression of DNA damage and potential senescence marker p21 exclusively in the endothelium, as demonstrated in aorta. Also the kidney showed p21-positive cells. Vasodilator responses measured in organ baths were decreased in aorta, iliac and coronary artery EC-KO compared with WT, of which coronary artery was the earliest to be affected. Nitric oxide-mediated endothelium-dependent vasodilation was abolished in aorta and coronary artery, whereas endothelium-derived hyperpolarization and responses to exogenous nitric oxide (NO) were intact. EC-KO showed increased superoxide production compared with WT, as measured in lung tissue, rich in endothelial cells (ECs). Arterial systolic blood pressure (BP) was increased at 3 months, but normal at 5 months, at which age cardiac output (CO) was decreased. Since no further signs of cardiac dysfunction were detected, this decrease might be an adaptation to prevent an increase in BP. In summary, a selective DNA repair defect in the endothelium produces features of age-related endothelial dysfunction, largely attributed to loss of endothelium-derived NO. Increased superoxide generation might contribute to the observed changes affecting end organ perfusion, as demonstrated in kidney and lung.


Assuntos
Envelhecimento/genética , Senescência Celular/genética , Dano ao DNA , Reparo do DNA , Proteínas de Ligação a DNA/deficiência , Endonucleases/deficiência , Células Endoteliais/metabolismo , Endotélio Vascular/metabolismo , Fatores Etários , Envelhecimento/metabolismo , Envelhecimento/patologia , Animais , Permeabilidade Capilar , Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Proteínas de Ligação a DNA/genética , Endonucleases/genética , Células Endoteliais/patologia , Endotélio Vascular/patologia , Endotélio Vascular/fisiopatologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Superóxidos/metabolismo , Rigidez Vascular , Vasodilatação
20.
Plant Mol Biol ; 102(6): 603-614, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32052233

RESUMO

The WRKY transcription factor family is involved in responding to biotic and abiotic stresses. Its members contain a typical WRKY domain and can regulate plant physiological responses by binding to W-boxes in the promoter regions of downstream target genes. We identified the sweet sorghum SbWRKY50 (Sb09g005700) gene, which encodes a typical class II of the WRKY family protein that localizes to the nucleus and has transcriptional activation activity. The expression of SbWRKY50 in sweet sorghum was reduced by salt stress, and its ectopic expression reduced the salt tolerance of Arabidopsis thaliana plants. Compared with the wild type, the germination rate, root length, biomass and potassium ion content of SbWRKY50 over-expression plants decreased significantly under salt-stress conditions, while the hydrogen peroxide, superoxide anion and sodium ion contents increased. Real-time PCR results showed that the expression levels of AtSOS1, AtHKT1 and genes related to osmotic and oxidative stresses in over-expression strains decreased under salt-stress conditions. Luciferase complementation imaging and yeast one-hybrid assays confirmed that SbWRKY50 could directly bind to the upstream promoter of the SOS1 gene in A. thaliana. However, in sweet sorghum, SbWRKY50 could directly bind to the upstream promoters of SOS1 and HKT1. These results suggest that the new WRKY transcription factor SbWRKY50 participates in plant salt response by controlling ion homeostasis. However, the regulatory mechanisms are different in sweet sorghum and Arabidopsis, which may explain their different salt tolerance levels. The data provide information that can be applied to genetically modifying salt tolerance in different crop varieties.


Assuntos
Homeostase , Tolerância ao Sal/fisiologia , Sorghum/genética , Sorghum/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Biomassa , Proteínas de Transporte , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Regulação da Expressão Gênica de Plantas , Germinação , Peróxido de Hidrogênio/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , Potássio/metabolismo , Regiões Promotoras Genéticas , Espécies Reativas de Oxigênio/metabolismo , Sementes , Sódio/metabolismo , Trocadores de Sódio-Hidrogênio/genética , Trocadores de Sódio-Hidrogênio/metabolismo , Estresse Fisiológico , Superóxidos/metabolismo , Simportadores/genética , Simportadores/metabolismo
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