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1.
PLoS Biol ; 18(9): e3000866, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32881857

RESUMO

The small GTPase RhoA is a central signaling enzyme that is involved in various cellular processes such as cytoskeletal dynamics, transcription, and cell cycle progression. Many signal transduction pathways activate RhoA-for instance, Gαq-coupled Histamine 1 Receptor signaling via Gαq-dependent activation of RhoGEFs such as p63. Although multiple upstream regulators of RhoA have been identified, the temporal regulation of RhoA and the coordination of different upstream components in its regulation have not been well characterized. In this study, live-cell measurement of RhoA activation revealed a biphasic increase of RhoA activity upon histamine stimulation. We showed that the first and second phase of RhoA activity are dependent on p63 and Ca2+/PKC, respectively, and further identified phosphorylation of serine 240 on p115 RhoGEF by PKC to be the mechanistic link between PKC and RhoA. Combined approaches of computational modeling and quantitative measurement revealed that the second phase of RhoA activation is insensitive to rapid turning off of the receptor and is required for maintaining RhoA-mediated transcription after the termination of the receptor signaling. Thus, two divergent pathways enable both rapid activation and persistent signaling in receptor-mediated RhoA signaling via intricate temporal regulation.


Assuntos
Histamina/farmacologia , Proteína rhoA de Ligação ao GTP/metabolismo , Animais , Sinalização do Cálcio/efeitos dos fármacos , Células Cultivadas , Ativação Enzimática/efeitos dos fármacos , Células HeLa , Humanos , Camundongos , Fosforilação/efeitos dos fármacos , Proteína Quinase C/metabolismo , Receptores Histamínicos/metabolismo , Fatores de Troca de Nucleotídeo Guanina Rho/metabolismo , Transdução de Sinais/efeitos dos fármacos
2.
Am J Med Sci ; 360(3): 279-286, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32829780

RESUMO

BACKGROUND: The essential role of 6-phosphogluconate dehydrogenase (6PGD), the enzyme catalyzing the oxidative pentose phosphate pathway, in tumor growth and metabolism has garnered attention in recent years. In this work, we are the first to demonstrate that aberrant activation of 6PGD is a feature in renal cell carcinoma (RCC) and is critically involved in renal carcinogenesis and chemo- and immuno-resistance. MATERIALS AND METHODS: 6PGD expression and activity were systematically analyzed in normal and malignant renal cells and tissues. The roles of 6PGD and its downstream mechanism were investigated using gain-of-function and loss-of-function approaches. RESULTS: 6PGD expression and enzyme activity were increased in RCC cells and patients' samples. Activation of 6PGD via gain-of-function approach promoted growth of normal kidney but not RCC cells, and alleviated the efficacy of chemotherapeutic (e.g., 5-FU) and immunotherapeutic (e.g., IFN-α) agents. In contrast, 6PGD inhibition using siRNA knockdown and pharmacological inhibitor physcion augmented the inhibitory effects of 5-FU and IFN-α in RCC. Mechanistic studies demonstrated that 6PGD inhibition activated AMPK signaling, leading to ACC1 enzyme inhibition and reduction of lipid synthesis. In addition, 6PGD inhibition disrupted NADPH and NADH homeostasis in RCC cells as shown by the decreased level of NADPH and NADH, and suppressed SIRT-1 activity. AMPK inhibition by siRNA knockdown reversed the inhibitory effects of physcion, demonstrating that the effect of 6PGD inhibition is AMPK activation dependent. CONCLUSIONS: Our work provides preclinical evidence that 6PGD inhibition may represent a potential therapeutic strategy to augment the efficacy of RCC standard of care drugs.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Carcinoma de Células Renais/terapia , Reprogramação Celular/fisiologia , Neoplasias Renais/terapia , Fosfogluconato Desidrogenase/metabolismo , Transdução de Sinais/fisiologia , Proteínas Quinases Ativadas por AMP/genética , Carcinoma de Células Renais/tratamento farmacológico , Carcinoma de Células Renais/patologia , Linhagem Celular , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/fisiologia , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Fluoruracila/uso terapêutico , Técnicas de Silenciamento de Genes , Humanos , Imunoterapia , Interferon-alfa/uso terapêutico , Rim/patologia , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/patologia , NADP/fisiologia , Fosfogluconato Desidrogenase/antagonistas & inibidores , Fosfogluconato Desidrogenase/genética , RNA Interferente Pequeno , Regulação para Cima
3.
Med Hypotheses ; 143: 110142, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32759013

RESUMO

BACKGROUND: Pulmonary hypertension is a significant complication for some patients with COVID-19 pneumonia, especially those requiring intensive care. Tachyphylaxis to the current therapy, inhaled nitric oxide (iNO), is also common. In vitro, folic acid directly increases nitric oxide (NO) production and extends its duration of action; effects which could be of benefit in reversing pulmonary hypertension and severe hypoxaemia. Our work has shown that, in the systemic circulation, folic acid in high dose rapidly improves nitric oxide mediated vasodilation, by activating endothelial nitric oxide synthase (eNOS). HYPOTHESIS: A similar effect of high dose folic acid on pulmonary endothelial function would be expected from the same mechanism and would lead to improvement in pulmonary perfusion. We therefore hypothesise that folic acid, 5 mg or greater, is a useful therapeutic option for pulmonary hypertension and/or refractory severe hypoxaemia, in patients with severe COVID-19 associated pneumonia in whom NO therapy is considered, with a very low risk of adverse effects.


Assuntos
Betacoronavirus , Infecções por Coronavirus/complicações , Ácido Fólico/uso terapêutico , Hipertensão Pulmonar/tratamento farmacológico , Óxido Nítrico/metabolismo , Pandemias , Pneumonia Viral/complicações , Administração por Inalação , Animais , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/fisiologia , Ativação Enzimática/efeitos dos fármacos , Ácido Fólico/administração & dosagem , Ácido Fólico/farmacologia , Humanos , Hipertensão Pulmonar/complicações , Hipóxia/tratamento farmacológico , Hipóxia/etiologia , Camundongos , Óxido Nítrico/administração & dosagem , Óxido Nítrico/uso terapêutico , Óxido Nítrico Sintase Tipo III/efeitos dos fármacos , Taquifilaxia
4.
PLoS Biol ; 18(6): e3000732, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32603375

RESUMO

Coordination of gene expression with nutrient availability supports proliferation and homeostasis and is shaped by protein acetylation. Yet how physiological/pathological signals link acetylation to specific gene expression programs and whether such responses are cell-type-specific is unclear. AMP-activated protein kinase (AMPK) is a key energy sensor, activated by glucose limitation to resolve nutrient supply-demand imbalances, critical for diabetes and cancer. Unexpectedly, we show here that, in gastrointestinal cancer cells, glucose activates AMPK to selectively induce EP300, but not CREB-binding protein (CBP). Consequently, EP300 is redirected away from nuclear receptors that promote differentiation towards ß-catenin, a driver of proliferation and colorectal tumorigenesis. Importantly, blocking glycogen synthesis permits reactive oxygen species (ROS) accumulation and AMPK activation in response to glucose in previously nonresponsive cells. Notably, glycogen content and activity of the ROS/AMPK/EP300/ß-catenin axis are opposite in healthy versus tumor sections. Glycogen content reduction from healthy to tumor tissue may explain AMPK switching from tumor suppressor to activator during tumor evolution.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Neoplasias Colorretais/metabolismo , Proteína p300 Associada a E1A/metabolismo , Glucose/farmacologia , Animais , Proteína de Ligação a CREB/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Neoplasias Colorretais/patologia , Ativação Enzimática/efeitos dos fármacos , Glicogênio/metabolismo , Camundongos Endogâmicos C57BL , Ligação Proteica/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , beta Catenina/metabolismo
5.
Life Sci ; 258: 118151, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32726661

RESUMO

AIMS: Hepatic glucose metabolism involves a variety of catabolic and anabolic pathways, and the dynamic balance of glucose metabolism is regulated in response to environmental and nutritional changes. The molecular mechanism of glucose metabolism in liver is complex and has not been fully elucidated so far. In this study, we hope to elucidate the target and mechanism of cinnamaldehyde (CA) in regulating glucose metabolism. MATERIALS AND METHODS: Molecular image tracing and magnetic capture in combination with an alkynyl-CA probe (Al-CA) was used to show CA covalently binds to α-enolase (ENO1) in both mouse liver and HepG2 cells. Accurate metabolic flow assays subsequently demonstrated that the utilization of glycogenic amino acids and the biosynthesis of tricarboxylic acid (TCA) cycle intermediates were strengthened, which was detected using nontargeted and targeted metabolomics analyses. KEY FINDINGS: Our study shows that CA covalently bonds with ENO1, which affects the stability and activity of ENO1 and changes the dynamic balance of glucose metabolism. The interruption of gluconeogenic reflux by ENO1 enhanced TCA cycle, and eventually led to a decrease in blood glucose and the improvement of mitochondrial efficiency. SIGNIFICANCE: These results provide a detailed description of how CA maintains the dynamic balance of glucose utilization and improves energy metabolism.


Assuntos
Acroleína/análogos & derivados , Biomarcadores Tumorais/metabolismo , Proteínas de Ligação a DNA/metabolismo , Ativação Enzimática/efeitos dos fármacos , Aromatizantes/farmacologia , Gluconeogênese/efeitos dos fármacos , Glucose/metabolismo , Fosfopiruvato Hidratase/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Acroleína/farmacologia , Animais , Ciclo do Ácido Cítrico/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Células Hep G2 , Humanos , Camundongos , Simulação de Acoplamento Molecular
6.
Rev Bras Parasitol Vet ; 29(2): e019819, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32609242

RESUMO

We investigated the in vitro acaricide activity of the methanolic extract (ME) and alkaloid-rich fraction (AF) of Prosopis juliflora on Rhipicephalus microplus and correlated this effect with acetylcholinesterase (AChE) inhibition. The acaricide activity was evaluated using adult and larval immersion tests. Also, we studied the possible interaction mechanism of the major alkaloids present in this fraction via molecular docking at the active site of R. microplus AChE1 (RmAChE1). Higher reproductive inhibitory activity of the AF was recorded, with effective concentration (EC50) four times lower than that of the ME (31.6 versus 121 mg/mL). The AF caused mortality of tick larvae, with lethal concentration 50% (LC50) of 13.8 mg/mL. Both ME and AF were seen to have anticholinesterase activity on AChE of R. microplus larvae, while AF was more active with half-maximal inhibitory concentration (IC50) of 0.041 mg/mL. The LC-MS/MS analyses on the AF led to identification of three alkaloids: prosopine (1), juliprosinine (2) and juliprosopine (3). The molecular docking studies revealed that these alkaloids had interactions at the active site of the RmAChE1, mainly relating to hydrogen bonds and cation-pi interactions. We concluded that the alkaloids of P. juliflora showed acaricide activity on R. microplus and acted through an anticholinesterase mechanism.


Assuntos
Alcaloides , Colinesterases , Extratos Vegetais , Prosopis , Rhipicephalus , Acaricidas/farmacologia , Alcaloides/farmacologia , Animais , Colinesterases/metabolismo , Cromatografia Líquida , Ativação Enzimática/efeitos dos fármacos , Larva , Simulação de Acoplamento Molecular , Extratos Vegetais/farmacologia , Prosopis/química , Rhipicephalus/efeitos dos fármacos , Rhipicephalus/enzimologia , Espectrometria de Massas em Tandem
7.
Arch Microbiol ; 202(8): 2105-2115, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32500253

RESUMO

In this study, the antibacterial, anti-efflux, anti-biofilm, anti-slime (exopolysaccharide) production and urease inhibitory efficacies of green synthesized gold nanoparticles (AuNPs) coated Anthemis atropatana extract against multidrug- resistant (MDR) Klebsiella pneumoniae strains were evaluated. The green synthesized AuNPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffractometer (XRD), particle size distribution, zeta potential and Fourier-transform infrared spectroscopy (FTIR). Then, antibacterial, anti-slime (exopolysaccharide) production, anti-biofilm and anti-efflux activities of AuNPs were investigated using micro-dilation, Congored agar, microtiter plate and MIC of ethidium bromide methods, respectively. Subsequently, the expression of mrkA, wzm and acrB genes was evaluated using quantitative Real-Time PCR (qRT-PCR). The synthesized AuNPs exhibited antibacterial activity against MDR strains of K. pneumoniae (minimum inhibitory concentration (MIC) of 6.25-50 µg/ml), as well as showed significant anti-slime (exopolysaccharide) production, anti-biofilm and anti-efflux activities against MDR strains. AuNPs showed significant inhibition against jack-bean urease and down-regulated the expression of mrkA, wzm and acrB genes. Moreover, the in vitro cytotoxic activity confirmed by MTT assay on the HEK-293 normal cell line showed negligible cytotoxicity. Thus, the present study suggests the potential use of AuNPs in the development of novel therapeutics for the prevention of biofilm-associated K. pneumoniae infections.


Assuntos
Anthemis/química , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Ouro/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , Nanopartículas Metálicas , Extratos Vegetais/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Ouro/química , Células HEK293 , Humanos , Nanopartículas Metálicas/química , Testes de Sensibilidade Microbiana , Extratos Vegetais/química , Urease/metabolismo
8.
Int J Nanomedicine ; 15: 3291-3302, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32494130

RESUMO

Background: Inhaled nanoparticles can cross pulmonary air-blood barrier into circulation and cause vascular endothelial injury and progression of cardiovascular disease. However, the molecular mechanism underlying the vascular toxicity of copper oxide nanoparticles (CuONPs) remains unclear. We have recently demonstrated that the release of copper ions and the accumulation of superoxide anions contributed to CuONPs-induced cell death in human umbilical vein endothelial cells (HUVECs). Herein, we further demonstrate the mechanism underlying copper ions-induced cell death in HUVECs. Methods and Results: CuONPs were suspended in culture medium and vigorously vortexed for several seconds before exposure. After treatment with CuONPs, HUVECs were collected, and cell function assays were conducted to elucidate cellular processes including cell viability, oxidative stress, DNA damage and cell signaling pathways. We demonstrated that CuONPs uptake induced DNA damage in HUVECs as evidenced by γH2AX foci formation and increased phosphorylation levels of ATR, ATM, p53 and H2AX. Meanwhile, we showed that CuONPs exposure induced oxidative stress, indicated by the increase of cellular levels of superoxide anions, the upregulation of protein levels of heme oxygenase-1 (HO-1) and glutamate-cysteine ligase modifier subunit (GCLM), the elevation of the levels of malondialdehyde (MDA), but the reduction of glutathione to glutathione disulfide ratio. We also found that antioxidant N-acetyl-L-cysteine (NAC) could ameliorate CuONPs-induced oxidative stress and cell death. Interestingly, we demonstrated that p38 mitogen-activated protein kinase (MAPK) signaling pathway was activated in CuONPs-treated HUVECs, while p38α MAPK knockdown by siRNA significantly rescued HUVECs from CuONPs-induced DNA damage and cell death. Importantly, we showed that copper ions chelator tetrathiomolybdate (TTM) could alleviate CuONPs-induced oxidative stress, DNA damage, p38 MAPK pathway activation and cell death in HUVECs. Conclusion: We demonstrated that CuONPs induced oxidative DNA damage and cell death via copper ions-mediated p38 MAPK activation in HUVECs, suggesting that the release of copper ions was the upstream activator for CuONPs-induced vascular endothelial toxicity, and the copper ions chelator TTM can alleviate CuONPs-associated cardiovascular disease.


Assuntos
Cobre/toxicidade , Dano ao DNA , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/patologia , Nanopartículas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Morte Celular/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Modelos Biológicos , Molibdênio/química , Nanopartículas/ultraestrutura
9.
Toxicol Appl Pharmacol ; 401: 115102, 2020 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-32512071

RESUMO

PURPOSE: Cadmium (Cd) is reported to be associated with carcinogenesis. The molecular mechanisms associated with Cd-induced prostate cancer (PCa) remain elusive. MATERIALS AND METHODS: RWPE1, PWR1E and DU 145 cells were used. RT2 Profiler Array, real-time-quantitative-PCR, immunofluorescence, cell cycle, apoptosis, proliferation and colony formation assays along with Gene Set Enrichment Analysis (GSEA) were performed. RESULT: Chronic Cd exposure of non-malignant RWPE1 and PWR1E cells promoted cell survival, proliferation and colony formation with inhibition of apoptosis. Even a two-week Cd exposure of PCa cell line (DU 145) significantly increased the proliferation and decreased apoptosis. RT2 profiler array of 84 genes involved in the Erk/MAPK pathway revealed induction of gene expression in Cd-RWPE1 cells compared to RWPE1. This was confirmed by individual TaqMan gene expression analysis in both Cd-RWPE1 and Cd-PWR1E cell lines. GSEA showed an enrichment of the Erk/MAPK pathway along with other pathways such as KEGG-ERBB, KEGG-Cell Cycle, KEGG-VEGF, KEGG-Pathways in cancer and KEGG-prostate cancer pathway. We randomly selected upregulated genes from Erk/MAPK pathway and performed profile analysis in a PCa data set from the TCGA/GDC data base. We observed upregulation of these genes in PCa compared to normal samples. An increase in phosphorylation of the Erk1/2 and Mek1/2 was observed in Cd-RWPE1 and Cd-PWR1E cells compared to parental cells, confirming that Cd-exposure induces activation of the Erk/MAPK pathway. CONCLUSION: This study demonstrates that Erk/MAPK signaling is a major pathway involved in Cd-induced malignant transformation of normal prostate cells. Understanding these dominant oncogenic pathways may help develop optimal therapeutic strategies for PCa.


Assuntos
Cádmio/toxicidade , Sistema de Sinalização das MAP Quinases/fisiologia , Próstata/efeitos dos fármacos , Próstata/enzimologia , Neoplasias da Próstata/induzido quimicamente , Neoplasias da Próstata/enzimologia , Carcinogênese/efeitos dos fármacos , Carcinogênese/metabolismo , Linhagem Celular Tumoral , Estudos de Coortes , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Próstata/patologia , Neoplasias da Próstata/patologia
10.
PLoS One ; 15(6): e0233563, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32497050

RESUMO

Activation of the steroidogenic enzyme CYP11A1 was shown to be necessary for the development of peanut-induced intestinal anaphylaxis and IL-13 production in allergic mice. We determined if levels of CYP11A1 in peripheral blood T cells from peanut-allergic (PA) children compared to non-allergic controls were increased and if levels correlated to IL-13 production and oral challenge outcomes to peanut. CYP11A1 mRNA and protein levels were significantly increased in activated CD4+ T cells from PA patients. In parallel, IL-13 production was significantly increased; IFNγ levels were not different between groups. There were significant correlations between expression levels of CYP11A1 mRNA and levels of IL13 mRNA and protein, levels of serum IgE anti-Ara h 2 and to outcomes of peanut challenge. The importance of CYP11A1 on cytokine production was tested using a CYP11A1 CRISPR/Cas9 KO plasmid or an inhibitor of enzymatic CYP11A1 activity. Inhibition of CYP11A1 activation in patient cells treated with the inhibitor, aminoglutethimide, or CD4+ T cell line transfected with the CYP11A1 KO plasmid resulted in reduced IL-13 production. These data suggest that the CYP11A1-CD4+Tcell-IL-13 axis in activated CD4+ T cells from PA children is associated with development of PA reactions. CYP11A1 may represent a novel target for therapeutic intervention in PA children.


Assuntos
Enzima de Clivagem da Cadeia Lateral do Colesterol/genética , Enzima de Clivagem da Cadeia Lateral do Colesterol/metabolismo , Interleucina-13/biossíntese , Hipersensibilidade a Amendoim/imunologia , Células Th2/imunologia , Adolescente , Aminoglutetimida/farmacologia , Linhagem Celular , Criança , Pré-Escolar , Enzima de Clivagem da Cadeia Lateral do Colesterol/antagonistas & inibidores , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/genética , Feminino , Técnicas de Inativação de Genes , Humanos , Ativação Linfocitária , Masculino , Hipersensibilidade a Amendoim/sangue , RNA Mensageiro/genética , Transfecção , Adulto Jovem
11.
Chem Biol Interact ; 325: 109109, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32376239

RESUMO

A series of 10 natural and semisynthetic flavonoids (1 to 10) were obtained from Gardenia oudiepe (Rubiaceae), an endemic plant from New Caledonia. Most of them were polymethoxylated flavones (PMFs) of rare occurrence. After a cell viability screening test, PMFs 2 and 3 showed significant cytotoxic activity against A2058 human melanoma cells (IC50 = 3.92 and 8.18 µM, respectively) and were selected for in-depth pharmacological assays. Both compounds inhibited cell migration and induced apoptosis and cell cycle arrest after 72h of treatment. Immunofluorescence assays indicated that these outcomes were possibly related to the induction of cytoskeleton disruption associated to actin and tubulin depolymerization. These data were confirmed by molecular docking studies, which showed a good interaction between PMFs 2 and 3 and tubulin, particularly at the colchicine binding site. As A2058 are considered as chemoresistant to conventional chemotherapy, compounds 2 and 3 (½IC50) were associated to clinically-used antimelanoma drugs (vemurafenib and dacarbazine) and combined therapies efficacy was assessed by the MTT assay. PMFs 2 restored the sensitivity of A2058 cells to dacarbazine treatment (IC50 = 49.38 µM vs. >100 µM). Taken together, these data suggest that PMFs from G. oudiepe could be potential leaders for the design of new antimelanoma drugs.


Assuntos
Apoptose/efeitos dos fármacos , Citoesqueleto/efeitos dos fármacos , Flavonas/farmacologia , Gardenia/química , Melanoma/patologia , Mutação , Proteínas Proto-Oncogênicas B-raf/genética , Antineoplásicos/farmacologia , Caspase 3/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Citoesqueleto/metabolismo , Sinergismo Farmacológico , Ativação Enzimática/efeitos dos fármacos , Flavonas/química , Flavonas/metabolismo , Humanos , Simulação de Acoplamento Molecular , Conformação Proteica , Relação Estrutura-Atividade , Tubulina (Proteína)/química , Tubulina (Proteína)/metabolismo
12.
J Med Microbiol ; 69(5): 689-696, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32375980

RESUMO

Introduction. Rhein (4, 5-dihydroxyanthraquinone-2-carboxylic acid) has various properties, including anti-inflammatory, antioxidant and anticancer activities. However, the mechanism underlying the role of rhein in antimicrobial activity remains largely unknown.Aim. This study aims to identify potential natural compounds of rhein that are capable of inhibiting Cutibacterium acnes and elucidate the effects of rhein on NADH dehydrogenase-2 activity in C. acnes.Methodology. The anti-C. acnes activity of compounds was analysed using minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), the paper disc diffusion test and the checkerboard dilution test. To check whether rhein was inhibitory, putative type II NADH dehydrogenase (NDH-2) of C. acnes was analysed, cloned and expressed in Escherichia coli, and then NDH-2 purification was assessed with Ni-NTA before rhein inhibition of NADH dehydrogenase-2 activity was checked with ferricyanide [K3Fe(CN)6] as a substrate.Results. The results showed that the MIC of rhein against C. acnes was 6.25 µg ml-1, while the MBC was 12.5 µg ml-1, and there was a 38 mm inhibition zone in the paper disc diffusion test. Rhein showed an additive two- to fourfold reduction of the MIC value with four antibiotics on the checkerboard dilution test. The purified NADH dehydrogenase gene product showed a size of approximately 51 kDa and had a V max of 23 µmol and a K m of 280 µm. The inhibitory effect of rhein against NADH dehydrogenase-2 activity was non-competitive with ferricyanide [K3Fe(CN)6] with a K i value of 3.5-4.5 µm.Conclusion. This study provided evidence of the inhibitory effects of rhein on the growth of C. acnes by blocking of NADH dehydrogenase-2 activity. This mechanism of inhibitory activity in the reduction of ROS formation and ATP productivity should be further tested in C. acnes and the question of whether rhein inhibits the natural growth of C. acnes should be investigated.


Assuntos
Antraquinonas/farmacologia , Antibacterianos/farmacologia , Inibidores Enzimáticos/farmacologia , Infecções por Bactérias Gram-Positivas/microbiologia , NADH Desidrogenase/antagonistas & inibidores , Propionibacterium acnes/efeitos dos fármacos , Propionibacterium acnes/enzimologia , Antraquinonas/uso terapêutico , Antibacterianos/uso terapêutico , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/uso terapêutico , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Humanos , Cinética , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Propionibacterium acnes/crescimento & desenvolvimento , Espécies Reativas de Oxigênio/metabolismo , Proteínas Recombinantes
13.
Chem Biol Interact ; 325: 109126, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32430275

RESUMO

Alzheimer's disease (AD) is a common neurodegenerative disease, and its pathogenesis is closely related to ß-amyloid (Aß) peptide. The deposition of Aß in the brain due to impaired Aß clearance is considered as an important cause of AD. The decrease in Aß clearance is closely related to the autophagy dysfunction in brains of AD patients. It is feasible to treat AD by increasing the autophagy level of cells such as microglia and neurons to accelerate Aß clearance. In this article we explored the ability of graphene oxide (GO) to clear Aß through activating autophagy. Our work demonstrated that GO could inhibit the mTOR signaling pathway by activating AMPK to induce the autophagy of microglial and neurons. As expected, with the improvement of autophagy ability of microglia, GO promoted microglia-mediated Aß phagocytosis. Under the conditions of co-culture of microglia and neurons, GO induced the autophagy of microglia and neurons, especially the autophagy of microglia, thereby promoting the clearance of Aß, and ultimately achieved the effect of protecting neurons. Moreover, GO was not only non-cytotoxic to microglia and neurons but also able to reduce the toxicity of Aß to neurons through its clearance. These results have shown the potential of GO in treating Alzheimer's disease.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Autofagia/efeitos dos fármacos , Grafite/farmacologia , Microglia/citologia , Microglia/efeitos dos fármacos , Neurônios/citologia , Neurônios/efeitos dos fármacos , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Linhagem Celular Tumoral , Ativação Enzimática/efeitos dos fármacos , Humanos , Camundongos , Microglia/metabolismo , Neurônios/metabolismo , Fagocitose/efeitos dos fármacos
14.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 32(3): 290-293, 2020 Apr 26.
Artigo em Chinês | MEDLINE | ID: mdl-32468792

RESUMO

OBJECTIVE: To evaluate the effects of Cu2+ and Cd2+ at different concentrations on superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity in Oncomelania hupensis. METHODS: Cu2+- and Cd2+-containing solutions were prepared at 7 concentrations, and O. hupensis snails were exposed to the solutions for 24 h, of 15 snails in each concentration. Then, the snail body was collected following removal of the snail shell and homogenated, and the SOD, CAT and POS activities were detected in the supernatants. RESULTS: With the increase of the Cu2+ concentration, the SOD activity appeared a rise followed by a reduction in O. hupensis snails, and the CTA activity appeared a decline-rise-decline tendency, while the POD activity showed a tendency towards rise followed by decline. With the increase of the Cd2+ concentration, the SOD activity appeared a rise followed by a reduction in O. hupensis snails, and the CTA activity appeared a decline- rise- decline tendency, while the POD activity showed a decline-rise-decline tendency. CONCLUSIONS: Exposure to Cu2+ and Cd2+ at high concentrations results in a decline in the activity of SOD, CAT and POD in O. hupensis at the same time.


Assuntos
Cádmio , Cobre , Oxirredutases , Caramujos , Animais , Cádmio/toxicidade , Catalase/metabolismo , Cobre/toxicidade , Ativação Enzimática/efeitos dos fármacos , Íons/toxicidade , Oxirredutases/metabolismo , Peroxidase/metabolismo , Caramujos/efeitos dos fármacos , Caramujos/enzimologia , Superóxido Dismutase/metabolismo
15.
Artigo em Inglês | MEDLINE | ID: mdl-32361224

RESUMO

Split application could improve nitrogen (N) uptake and increase sweetpotato yields under reduced N supply; however, little is known about how it affects the process of starch production in storage roots. An experiment was conducted to determine the effects of three N management strategies [conventional basal N management; 80% of the conventional N rate applied as a basal fertilizer; 80% of the conventional N rate equally split at transplanting and 35 days after transplanting] on starch accumulation, enzyme activity and genes expression in the conversion of sucrose to starch and the relationships among them. The results showed that, compared with conventional basal N management, split application decreased sucrose accumulation by 11.78%, but increased starch accumulation by 11.12% through improving the starch accumulation rate under reduced N supply. The ratio of sucrose synthetase to sucrose phosphate synthase, the enzymatic activity of ADP-glucose pyrophosphorylase (AGPP), starch synthase, and the expression of their corresponding genes were promoted by split application under reduced N supply and were positively correlated with starch accumulation rate. AGPP is the rate-limiting enzyme in starch synthesis in storage roots under different N management strategies. These results indicate that starch accumulation was enhanced by split application through regulating the activity and gene expression of key enzymes involved in the conversion of sucrose to starch under reduced N supply.


Assuntos
Ipomoea batatas , Nitrogênio , Amido , Sacarose , Ativação Enzimática/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glucose-1-Fosfato Adenililtransferase/genética , Glucose-1-Fosfato Adenililtransferase/metabolismo , Ipomoea batatas/efeitos dos fármacos , Ipomoea batatas/enzimologia , Ipomoea batatas/genética , Ipomoea batatas/metabolismo , Nitrogênio/farmacologia , Amido/biossíntese , Sacarose/metabolismo
16.
J Neurosci ; 40(23): 4609-4619, 2020 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-32350039

RESUMO

Idebenone is a synthetic quinone that on reduction in cells can bypass mitochondrial Complex I defects by donating electrons to Complex III. The drug is used clinically to treat the Complex I disease Leber's hereditary optic neuropathy (LHON), but has been less successful in clinical trials for other neurodegenerative diseases. NAD(P)H:quinone oxidoreductase 1 (NQO1) appears to be the main intracellular enzyme catalyzing idebenone reduction. However, NQO1 is not universally expressed by cells of the brain. Using primary rat cortical cells pooled from both sexes, we tested the hypotheses that the level of endogenous NQO1 activity limits the ability of neurons, but not astrocytes, to use idebenone as an electron donor to support mitochondrial respiration. We then tested the prediction that NQO1 induction by pharmacological activation of the transcription factor nuclear erythroid 2-related factor 2 (Nrf2) enables idebenone to bypass Complex I in cells with poor NQO1 expression. We found that idebenone stimulated respiration by astrocytes but reduced the respiratory capacity of neurons. Importantly, idebenone supported mitochondrial oxygen consumption in the presence of a Complex I inhibitor in astrocytes but not neurons, and this ability was reversed by inhibiting NQO1. Conversely, recombinant NQO1 delivery to neurons prevented respiratory impairment and conferred Complex I bypass activity. Nrf2 activators failed to increase NQO1 in neurons, but carnosic acid induced NQO1 in COS-7 cells that expressed little endogenous enzyme. Carnosic acid-idebenone combination treatment promoted NQO1-dependent Complex I bypass activity in these cells. Thus, combination drug strategies targeting NQO1 may promote the repurposing of idebenone for additional disorders.SIGNIFICANCE STATEMENT Idebenone is used clinically to treat loss of visual acuity in Leber's hereditary optic neuropathy. Clinical trials for several additional diseases have failed. This study demonstrates a fundamental difference in the way idebenone affects mitochondrial respiration in cortical neurons compared with cortical astrocytes. Cortical neurons are unable to use idebenone as a direct mitochondrial electron donor due to NQO1 deficiency. Our results suggest that idebenone behaves as an NQO1-dependent prodrug, raising the possibility that lack of neuronal NQO1 activity has contributed to the limited efficacy of idebenone in neurodegenerative disease treatment. Combination therapy with drugs able to safely induce NQO1 in neurons, as well as other brain cell types, may be able to unlock the neuroprotective therapeutic potential of idebenone or related quinones.


Assuntos
Antioxidantes/farmacologia , Astrócitos/enzimologia , Respiração Celular/fisiologia , Mitocôndrias/enzimologia , NAD(P)H Desidrogenase (Quinona)/metabolismo , Ubiquinona/análogos & derivados , Animais , Animais Recém-Nascidos , Astrócitos/efeitos dos fármacos , Células COS , Respiração Celular/efeitos dos fármacos , Células Cultivadas , Chlorocebus aethiops , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Feminino , Masculino , Mitocôndrias/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Ubiquinona/farmacologia
17.
PLoS One ; 15(5): e0233180, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32437392

RESUMO

Lipoprotein lipase (LPL) is upregulated in atherosclerotic lesions and it may promote the progression of atherosclerosis, but the mechanisms behind this process are not completely understood. We previously showed that the phosphorylation of Akt within THP-1 macrophages is increased in response to the lipid hydrolysis products generated by LPL from total lipoproteins. Notably, the free fatty acid (FFA) component was responsible for this effect. In the present study, we aimed to reveal more detail as to how the FFA component may affect Akt signalling. We show that the phosphorylation of Akt within THP-1 macrophages increases with total FFA concentration and that phosphorylation is elevated up to 18 hours. We further show that specifically the palmitoleate component of the total FFA affects Akt phosphorylation. This is tied with changes to the levels of select molecular species of phosphoinositides. We further show that the total FFA component, and specifically palmitoleate, reduces apolipoprotein A-I-mediated cholesterol efflux, and that the reduction can be reversed in the presence of the Akt inhibitor MK-2206. Overall, our data support a negative role for the FFA component of lipoprotein hydrolysis products generated by LPL, by impairing macrophage cholesterol efflux via Akt activation.


Assuntos
Colesterol/metabolismo , Macrófagos/metabolismo , Ácido Palmítico/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Apolipoproteína A-I/metabolismo , Ativação Enzimática/efeitos dos fármacos , Compostos Heterocíclicos com 3 Anéis/farmacologia , Humanos , Lipase Lipoproteica/metabolismo , Macrófagos/citologia , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Células THP-1
18.
Phys Chem Chem Phys ; 22(15): 7942-7951, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32232288

RESUMO

A pharmacophoric motif decorated with supramolecular functionalities (TZT) was designed for potential interaction with biological targets. Main insights of this work include the correlation of supra functionalities of TZT with its binding ability to proteins leading to the modulation of their structure and bioactivity as a promising perspective in the field of cellular protection from oxidative stress. To investigate the role of TZT in obliterating oxidative stress at a molecular level, its binding propensity with bovine serum albumin (BSA) and bovine liver catalase (BLC) was characterized using various biophysical methods. The binding constants of TZT with BSA (Kb = 2.09 × 105 M-1) and BLC (Kb = 2.349 × 105 M-1) indicate its considerable interaction with these proteins. TZT efficiently triggers favourable structural changes in BLC, thereby enhancing its enzyme activity in a dose dependent manner. The enzyme kinetics parameters of TZT binding to BLC were quantified using the Michaelis-Menten model. Both in silico and experimental results suggest that an increased substrate availability could be the reason for enhanced BLC activity. Furthermore, physiological relevance of this interaction was demonstrated by investigating the ability of TZT to attenuate oxidative stress. Treatment with TZT was found to mitigate the inhibition of A549 cell proliferation in the presence of high concentrations of vitamin C. This finding was confirmed at a molecular level by PARP cleavage status, demonstrating that TZT inhibits apoptotic cell death induced by oxidative stress.


Assuntos
Catalase/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Tiazolidinas/farmacologia , Células A549 , Animais , Antioxidantes/farmacologia , Bovinos , Proliferação de Células/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Humanos
19.
PLoS One ; 15(4): e0231212, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32275682

RESUMO

Two major proteolytic systems, the proteasome and the autophagy pathway, are key components of the proteostasis network. The immunoproteasome, a proteasome subtype, and autophagy are upregulated under stress conditions, forming a coordinated unit designed to minimize the effect of cell stress. We investigated how genetic ablation of the LMP2 immunoproteasome subunit affects autophagy in retinal pigment epithelium (RPE) from WT and LMP2 knockout mice. We monitored autophagy regulation by measuring LC3, phosphorylation of AKT (S473), and phosphorylation of S6, a downstream readout of AKT (mTOR) pathway activation. We also evaluated transcription factor EB (TFEB) nuclear translocation, a transcription factor that controls expression of autophagy and lysosome genes. WT and LMP2 KO cells were monitored after treatment with EBSS to stimulate autophagy, insulin to stimulate AKT, or an AKT inhibitor (trehalose or MK-2206). Under basal conditions, we observed hyper-phosphorylation of AKT and S6, as well as lower nuclear-TFEB content in LMP2 KO RPE compared with WT. AKT inhibitors MK-2206 and trehalose significantly inhibited AKT phosphorylation and stimulated nuclear translocation of TFEB. Starvation and AKT inhibition upregulated autophagy, albeit to a lesser extent in LMP2 KO RPE. These data support the idea that AKT hyper-activation is an underlying cause of defective autophagy regulation in LMP2 KO RPE, revealing a unique link between two proteolytic systems and a previously unknown function in autophagy regulation by the immunoproteasome.


Assuntos
Autofagia , Complexo de Endopeptidases do Proteassoma/imunologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Retina/citologia , Animais , Autofagia/efeitos dos fármacos , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Células Cultivadas , Cisteína Endopeptidases/metabolismo , Ativação Enzimática/efeitos dos fármacos , Células HEK293 , Humanos , Insulina/farmacologia , Camundongos Knockout , Fosforilação/efeitos dos fármacos , Transporte Proteico/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Epitélio Pigmentado da Retina/citologia , Transdução de Sinais/efeitos dos fármacos
20.
Plant Physiol Biochem ; 151: 429-437, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32289636

RESUMO

Potassium (K+) has been reported to alleviate ammonium (NH4+) toxicity in rice through some underlying mechanisms, but it still not clear. In addition, K+ is an important cation for activation of plasma membrane (PM) H+-ATPase activity. Here, we hypothesized that K+ alleviated NH4+ toxicity by mediating PM H+-ATPase function in rice root. In this study, rice plants were cultivated in hydroponic solution with various concentrations of K+ and NH4+. By concurrently supplying K+ with NH4+ or re-supplying K+ after NH4+ toxicity, we found that high K+ concentration reduced the NH4+ uptake rate, enhanced the H+ extrusion rate by the roots, and alleviated rice NH4+ toxicity. The gene expression levels of PM H+-ATPase members (OsA1, 3, 7, 8, and 9) were upregulated by application of increasing concentrations of K+ under NH4+ toxicity. The PM H+-ATPase activity and protein expression in rice roots were also enhanced. Furthermore, the enhancement of PM H+-ATPase activity by a specific stimulator (fusicoccin) rescued rice seedlings from NH4+ toxicity. Taken together, these results indicate that K+ can alleviate NH4+ toxicity, possibly by activating PM H+-ATPase to extrude more H+ and inhibit NH4+ uptake by root. Our results may enhance understanding of the strategy of applying K+ fertilizer to mitigate crop NH4+ toxicity in agriculture.


Assuntos
Compostos de Amônio , Oryza , Potássio , ATPases Translocadoras de Prótons , Compostos de Amônio/metabolismo , Compostos de Amônio/toxicidade , Membrana Celular/efeitos dos fármacos , Membrana Celular/enzimologia , Ativação Enzimática/efeitos dos fármacos , Oryza/efeitos dos fármacos , Oryza/enzimologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Potássio/farmacologia , ATPases Translocadoras de Prótons/metabolismo
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