Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 116.895
Filtrar
1.
Acta Virol ; 63(3): 278-285, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31507193

RESUMO

Dengue virus (DENV) infection is one of the most widely-spread flavivirus infections with no effective antiviral drugs available. Peptide inhibitors have been considered as one of the best drug candidates due to their high specificity, selectivity in their interactions and minimum side effects. In this study, we employed computational studies using YASARA, HADDOCK server and PyMOL software to generate short and linear peptides based on a reference peptide, CP5-46A, to block DENV NS2B-NS3 protease. The inhibition potencies of the peptides were evaluated using in-house DENV2 serine protease and fluorogenic peptide substrates. In vitro analyses were performed to determine the peptides cytotoxicity and the inhibitory effects against DENV2 replication in WRL-68 cells. Our computational analyses revealed that the docking energy of AYA3, a 16 amino acid (aa) (-81.2 ± 10.6 kcal/mol) and AYA9, a 15 aa peptide (-83.8 ± 6.8 kcal/mol) to DENV NS2B-NS3 protease were much lower than the reference peptide (46 aa; -70.9 ± 7.8 kcal/mol) and the standard protease inhibitor, aprotinin (58 aa; -48.2 ± 10.6 kcal/mol). Both peptides showed significant inhibition against DENV2 NS2B-NS3 protease activity with IC50 values of 24 µM and 23 µM, respectively. AYA3 and AYA9 peptides also demonstrated approximately 68% and 83% of viral plaque reduction without significantly affecting cell viability at 50 µM concentration. In short, we generated short linear peptides with lower cytotoxic effect and substantial antiviral activities against DENV2. Further studies are required to investigate the inhibitory effects of these peptides in vivo. Keywords: peptide inhibitors; dengue virus; NS2B-NS3 protease; plaque reduction.


Assuntos
Antivirais , Vírus da Dengue , Peptídeos , Inibidores de Proteases , Replicação Viral , Antivirais/farmacologia , Biologia Computacional , Vírus da Dengue/enzimologia , Ativação Enzimática/efeitos dos fármacos , Humanos , Peptídeos/síntese química , Peptídeos/farmacologia , Inibidores de Proteases/farmacologia , Replicação Viral/efeitos dos fármacos
2.
Hum Genet ; 138(10): 1183-1200, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31471722

RESUMO

The glutamate pyruvate transaminase 2 (GPT2) gene produces a nuclear-encoded mitochondrial enzyme that catalyzes the reversible transfer of an amino group from glutamate to pyruvate, generating alanine and alpha-ketoglutarate. Recessive mutations in GPT2 have been recently identified in a new syndrome involving intellectual and developmental disability (IDD), postnatal microcephaly, and spastic paraplegia. We have identified additional families with recessive GPT2 mutations and expanded the phenotype to include small stature. GPT2 loss-of-function mutations were identified in four families, nine patients total, including: a homozygous mutation in one child [c.775T>C (p.C259R)]; compound heterozygous mutations in two siblings [c.812A>C (p.N271T)/c.1432_1433delGT (p.V478Rfs*73)]; a novel homozygous, putative splicing mutation [c.1035C>T (p.G345=)]; and finally, a recurrent mutation, previously identified in a distinct family [c.1210C>T (p.R404*)]. All patients were diagnosed with IDD. A majority of patients had remarkably small stature throughout development, many < 1st percentile for height and weight. Given the potential biological function of GPT2 in cellular growth, this phenotype is strongly suggestive of a newly identified clinical susceptibility. Further, homozygous GPT2 mutations manifested in at least 2 of 176 families with IDD (approximately 1.1%) in a Pakistani cohort, thereby representing a relatively common cause of recessive IDD in this population, with recurrence of the p.R404* mutation in this population. Based on variants in the ExAC database, we estimated that approximately 1 in 248 individuals are carriers of moderately or severely deleterious variants in GPT2.


Assuntos
Deficiências do Desenvolvimento/diagnóstico , Deficiências do Desenvolvimento/genética , Genes Recessivos , Predisposição Genética para Doença , Mutação , Fenótipo , Transaminases/genética , Adolescente , Alelos , Substituição de Aminoácidos , Deficiências do Desenvolvimento/metabolismo , Ativação Enzimática , Éxons , Feminino , Frequência do Gene , Estudos de Associação Genética , Genética Populacional , Genótipo , Humanos , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/genética , Imagem por Ressonância Magnética , Masculino , Mitocôndrias/genética , Mitocôndrias/metabolismo , Modelos Moleculares , Linhagem , Conformação Proteica , Sítios de Splice de RNA , Análise de Sequência de DNA , Relação Estrutura-Atividade , Transaminases/química , Transaminases/metabolismo
3.
Pestic Biochem Physiol ; 158: 156-165, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31378352

RESUMO

Culex pipiens is a main vector for Bancroftian filariasis, Rift Valley Fever and diseases caused by other viruses, leaving several peoples with disabilities. In recent years, plant derived compounds have received much attention as potential alternatives to synthetic chemicals due to their low toxicity to mammals and environmental persistence. Twenty-one monoterpenes from different chemical groups (hydrocarbons and oxygenated products) were evaluated against Culex pipiens larvae. In addition, in vivo biochemical studies including effects on acetylcholine esterase (AChE), acid and alkaline phosphatases (ACP and ALP), total adenosine triphosphatase (ATPase) and gamma-aminobutyric acid transaminase (GABA-T) were investigated. Furthermore, in silico studies including pharmacophore elucidation, ADMET analysis and molecular docking of these compounds were performed. Among all tested monoterpenes, hydrocarbons [p-cymene, (R)-(+)-limonene and (+)-α-pinene], acetates (cinnamyl acetate, citronellyl acetate, eugenyl acetate and terpinyl acetate), alcohols [(±)-ß-citronellol and terpineol], aldehydes [citral and (1R)-(-)-myrtenal] and ketone [(R)-(+)-pulegone] exhibited the highest larval toxicity with LC50 = 14.88, 27.97, 26.13, 2.62, 3.81, 2.74, 21.65, 1.64, 21.70, 21.76, 1.68 and 1.90 mg/L after 48 h of exposure, respectively. The compounds proved a significant inhibition of all tested enzymes except total ATPase. The biochemical and molecular docking studies proved that AChE and GABA-T were the main targets for the tested monoterpenes.


Assuntos
Culex/virologia , Inseticidas/farmacologia , Monoterpenos/farmacologia , Fosfatase Alcalina/metabolismo , Animais , Culex/patogenicidade , Filariose Linfática/transmissão , Ativação Enzimática/efeitos dos fármacos , Esterases/metabolismo , Simulação de Acoplamento Molecular , Transaminases/metabolismo
4.
Adv Exp Med Biol ; 1158: 119-142, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31452139

RESUMO

The mitochondrion is a vital organelle that performs diverse cellular functions. In this regard, the cell has evolved various mechanisms dedicated to the maintenance of the mitochondrial proteome. Among them, AAA+ ATPase-associated proteases (AAA+ proteases) such as the Lon protease (LonP1), ClpXP complex, and the membrane-bound i-AAA, m-AAA and paraplegin facilitate the clearance of misfolded mitochondrial proteins to prevent the accumulation of cytotoxic protein aggregates. Furthermore, these proteases have additional regulatory functions in multiple biological processes that include amino acid metabolism, mitochondria DNA transcription, metabolite and cofactor biosynthesis, maturation and turnover of specific respiratory and metabolic proteins, and modulation of apoptosis, among others. In cancer cells, the increase in intracellular ROS levels promotes tumorigenic phenotypes and increases the frequency of protein oxidation and misfolding, which is compensated by the increased expression of specific AAA+ proteases as part of the adaptation mechanism. The targeting of AAA+ proteases has led to the discovery and development of novel anti-cancer compounds. Here, we provide an overview of the molecular characteristics and functions of the major mitochondrial AAA+ proteases and summarize recent research efforts in the development of compounds that target these proteases.


Assuntos
Proteínas Mitocondriais , ATPases Associadas a Diversas Atividades Celulares/metabolismo , Ativação Enzimática , Humanos , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Neoplasias/enzimologia , Neoplasias/fisiopatologia , Neoplasias/terapia , Protease La/metabolismo
5.
J Enzyme Inhib Med Chem ; 34(1): 1178-1185, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31282230

RESUMO

The activation of the ß-class carbonic anhydrases (CAs, EC 4.2.1.1) from the bacteria Brucella suis and Francisella tularensis with amine and amino acids was investigated. BsuCA 1 was sensitive to activation with amino acids and amines, whereas FtuCA was not. The most effective BsuCA 1 activators were L-adrenaline and D-Tyr (KAs of 0.70-0.95 µM). L-His, L-/D-Phe, L-/D-DOPA, L-Trp, L-Tyr, 4-amino-L-Phe, dopamine, 2-pyridyl-methylamine, D-Glu and L-Gln showed activation constants in the range of 0.70-3.21 µM. FtuCA was sensitive to activation with L-Glu (KA of 9.13 µM). Most of the investigated compounds showed a weak activating effect against FtuCA (KAs of 30.5-78.3 µM). Many of the investigated amino acid and amines are present in high concentrations in many tissues in vertebrates, and their role in the pathogenicity of the two bacteria is poorly understood. Our study may bring insights in processes connected with invasion and pathogenic effects of intracellular bacteria.


Assuntos
Aminas/farmacologia , Aminoácidos/farmacologia , Brucella suis/enzimologia , Anidrases Carbônicas/metabolismo , Ativação Enzimática/efeitos dos fármacos , Francisella tularensis/enzimologia , Aminas/química , Aminoácidos/química , Anidrases Carbônicas/genética , Relação Estrutura-Atividade
6.
Phys Chem Chem Phys ; 21(28): 15747-15759, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31276128

RESUMO

The catalytic cofactor of the most common form of nitrogenase contains seven irons and one molybdenum bound together by sulfide bonds. Surprisingly, a central carbide has been demonstrated by experiments. Another noteworthy structural component is a large homocitrate ligand. In recent theoretical studies it has been shown that the central carbide is needed as a place for the incoming protons that are necessary parts of a reduction process. It has also been shown that a role for the homocitrate ligand could be that it may be rotated to release one bond to molybdenum. In the present study, the carbide protonation steps are reinvestigated with similar results to those reported before. The actual activation of N2 in the E4 state is an extremely complicated process. It has been found experimentally that two hydrides should leave as H2, in a reductive elimination process, to allow N2 activation in E4 in an easily reversible step. It is here suggested that after H2 is released, it is necessary for the metal cofactor to get rid of one proton. This is achieved by protonating the homocitrate and then rotating it to release one of the bonds to Mo. After this rotation, N2 can bind. In the E5 step, the homocitrate is rotated back to its original position and remains that way until the end of the catalytic process. The N2 protonation steps are energetically easy. Since a protonated carbide has never been observed experimentally, it is necessary to also have a mechanism for deprotonating the carbon at the end of the catalytic cycles. Such a mechanism is suggested here.


Assuntos
Nitrogenase/metabolismo , Carbono/química , Coenzimas/química , Ativação Enzimática , Metais/química , Nitrogenase/química , Prótons
7.
Cytogenet Genome Res ; 158(1): 17-24, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31261155

RESUMO

Osteoarthritis (OA) is a degenerative disease characterized by progressive articular cartilage destruction and joint marginal osteophyte formation with different degrees of synovitis. Docosahexaenoic acid (DHA) is an unsaturated fatty acid with anti-inflammatory, antioxidant, and antiapoptotic functions. In this study, the human chondrosarcoma cell line SW1353 was cultured in vitro, and an OA cell model was constructed with inflammatory factor IL-1ß stimulation. After cells were treated with DHA, cell apoptosis was measured. Western blot assay was used to detect protein expression of apoptosis-related factors (Bax, Bcl-2, and cleaved caspase-3) and mitogen-activated protein kinase (MAPK) signaling pathway family members, including extracellular signal-regulated kinase (ERK), c-JUN N-terminal kinase (JNK), and p38 MAPK. Our results show that IL-1ß promotes the apoptosis of SW1353 cells, increases the expression of Bax and cleaved caspase-3, and activates the MAPK signaling pathway. In contrast, DHA inhibits the expression of IL-1ß, inhibits IL-1ß-induced cell apoptosis, and has a certain inhibitory effect on the activation of the MAPK signaling pathway. When the MAPK signaling pathway is inhibited by its inhibitors, the effects of DHA on SW1353 cells are weakened. Thus, DHA enhances the apoptosis of SW1353 cells through the MAPK signaling pathway.


Assuntos
Apoptose/efeitos dos fármacos , Neoplasias Ósseas/patologia , Condrossarcoma/patologia , Ácidos Docosa-Hexaenoicos/farmacologia , Interleucina-1beta/antagonistas & inibidores , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Osteoartrite/tratamento farmacológico , Proteínas Reguladoras de Apoptose/biossíntese , Proteínas Reguladoras de Apoptose/genética , Butadienos/farmacologia , Linhagem Celular Tumoral , Avaliação Pré-Clínica de Medicamentos , Ativação Enzimática/efeitos dos fármacos , Indução Enzimática/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Interleucina-1beta/biossíntese , Interleucina-1beta/genética , Interleucina-1beta/farmacologia , Sistema de Sinalização das MAP Quinases/fisiologia , Proteínas Quinases Ativadas por Mitógeno/biossíntese , Proteínas Quinases Ativadas por Mitógeno/genética , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Nitrilos/farmacologia , Inibidores de Proteínas Quinases/farmacologia
8.
Life Sci ; 232: 116679, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31340168

RESUMO

AIMS: Amplified in liver cancer 1 gene (ALC1), a recently identified oncogene, was reported to be overexpressed in esophageal cancer cell lines and identified as a target oncogene in esophageal cancer pathogenesis. However, little literature is available to illustrate its significance in cisplatin resistance of esophageal squamous cell carcinoma (ESCC) cells. The aim of the current study was to investigate the effect of ALC1 on cisplatin cytotoxicity of ESCC cells and to study the potential mechanisms. MAIN METHODS: ALC1 at mRNA and protein levels were detected by qRT-PCR and western blot, respectively. Cell viability was evaluated using CCK-8 assay. Apoptosis was assessed using caspase-3/7 activity assay and flow cytometry analysis. Glycolysis level was evaluated by measuring glucose consumption and lactate production. The protein levels of p-protein kinase B (Akt) and Akt were determined by western blot. KEY FINDINGS: ALC1 was highly expressed in ESCC cells compared with human normal esophageal epithelial Het-1A cells. ALC1 knockdown suppressed the viability, induced apoptosis and enhanced cisplatin cytotoxicity in ESCC cells. In addition, ALC1 knockdown inhibited glycolysis and inactivated the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in ESCC cells. Mechanistically, activation of the PI3K/Akt pathway by 740Y-P blocked the effects of ALC1 knockdown on cisplatin cytotoxicity and glycolysis in ESCC cells. In contrast, inhibition of the PI3K/Akt pathway by LY294002 or glycolysis by 2-deoxyglucose resisted the effect of ALC1 overexpression on cisplatin cytotoxicity in ESCC cells. SIGNIFICANCE: ALC1 knockdown enhanced cisplatin cytotoxicity of ESCC cells by inhibition of glycolysis through inactivation of the PI3K/Akt pathway.


Assuntos
Antineoplásicos/farmacologia , Carcinoma de Células Escamosas/patologia , Cisplatino/farmacologia , DNA Helicases/genética , Proteínas de Ligação a DNA/genética , Neoplasias Esofágicas/patologia , Técnicas de Silenciamento de Genes , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Apoptose , Carcinoma de Células Escamosas/enzimologia , Carcinoma de Células Escamosas/metabolismo , Ativação Enzimática , Neoplasias Esofágicas/enzimologia , Neoplasias Esofágicas/metabolismo , Glicólise , Humanos , Células Tumorais Cultivadas
9.
Pestic Biochem Physiol ; 157: 60-68, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31153478

RESUMO

A series of novel substituted oxazole isoxazole carboxamides derivatives were designed on the basis of active subunit combination. Forty-four novel compounds were synthesized by an efficient one-pot procedure under microwave irradiation. The bioactivity was evaluated as herbicide safener against the injury of chlorsulfuron. It was found that most of the synthesized compounds displayed remarkable protection against chlorsulfuron via enhanced glutathione content and glutathione S transferase activity. Especially compound I-11 exhibited better bioactivity than the safeners isoxadifen-ethyl and R-28725. Molecular docking simulations suggested that the target compounds could compete with chlorsulfuron in the active site of acetolactate synthase, which could explain the protective effects of safeners. The present work demonstrates that the target compounds containing oxazole isoxazole groups could be considered as potential candidates for developing novel safeners in the future.


Assuntos
Herbicidas/química , Herbicidas/farmacologia , Isoxazóis/química , Oxazóis/química , Sulfonamidas/farmacologia , Triazinas/farmacologia , Acetolactato Sintase/genética , Acetolactato Sintase/metabolismo , Ativação Enzimática/efeitos dos fármacos , Glutationa/metabolismo , Glutationa Transferase/metabolismo , Relação Estrutura-Atividade , Zea mays/enzimologia
10.
Int J Oncol ; 55(1): 59-68, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31180529

RESUMO

The present study investigated the effects of the combined treatment of two peptide nucleic acids (PNAs), directed against microRNAs involved in caspase­3 mRNA regulation (miR­155­5p and miR­221­3p) in the temozolomide (TMZ)­resistant T98G glioma cell line. These PNAs were conjugated with an octaarginine tail in order to obtain an efficient delivery to treated cells. The effects of singularly administered PNAs or a combined treatment with both PNAs were examined on apoptosis, with the aim to determine whether reversion of the drug­resistance phenotype was obtained. Specificity of the PNA­mediated effects was analyzed by reverse transcription­quantitative polymerase­chain reaction, which demonstrated that the effects of R8­PNA­a155 and R8-PNA-a221 anti­miR PNAs were specific. Furthermore, the results obtained confirmed that both PNAs induced apoptosis when used on the temozolomide­resistant T98G glioma cell line. Notably, co­administration of both anti­miR­155 and anti­miR­221 PNAs was associated with an increased proapoptotic activity. In addition, TMZ further increased the induction of apoptosis in T98G cells co­treated with anti­miR­155 and anti­miR­221 PNAs.


Assuntos
Caspase 3/metabolismo , Glioma/tratamento farmacológico , Glioma/genética , MicroRNAs/antagonistas & inibidores , Ácidos Nucleicos Peptídicos/farmacologia , Temozolomida/farmacologia , Antineoplásicos Alquilantes/farmacologia , Apoptose/efeitos dos fármacos , Caspase 3/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Sinergismo Farmacológico , Ativação Enzimática/efeitos dos fármacos , Glioma/enzimologia , Humanos , MicroRNAs/genética , Ácidos Nucleicos Peptídicos/genética
11.
Int J Oncol ; 55(1): 21-34, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31180559

RESUMO

Emerging studies have indicated that leucine­rich repeat kinase 2 (LRRK2) is associated with thyroid cancer (TC). The present study investigated the effect of LRRK2 on the cell cycle and apoptosis in TC, and examined the underlying mechanisms in vitro. To screen TC­associated differentially expressed genes, gene expression microarray analysis was conducted. Retrieval of pathways associated with TC from the Kyoto Encyclopedia of Genes and Genomes database indicated that the c­Jun N­terminal kinase (JNK) signaling pathway serves an essential role in TC. SW579, IHH­4, TFC­133, TPC­1 and Nthy­ori3­1 cell lines were used to screen cell lines with the highest and lowest LRRK2 expression for subsequent experiments. The two selected cell lines were transfected with pcDNA­LRRK2, or small interfering RNA against LRRK2 or SP600125 (a JNK inhibitor). Subsequently, flow cytometry, terminal deoxynucleotidyl transferase­mediated dUTP­biotin nick end labeling, a 5­ethynyl­2'­deoxyuridine assay and a scratch test was conducted to detect the cell cycle distribution, apoptosis, proliferation and migration, respectively, in each group. The LRRK2 gene was determined to be elevated in TC based on the microarray data of the GSE3678 dataset. The SW579 cell line was identified to exhibit the highest LRRK2 expression, while IHH­4 cells exhibited the lowest LRRK2 expression. LRRK2 silencing, through inhibiting the activation of the JNK signaling pathway, increased the expression levels of genes and proteins associated with cell cycle arrest and apoptosis in TC cells, promoted cell cycle arrest and apoptosis, and inhibited cell migration and proliferation in TC cells, indicating that LRRK2 repression could exert beneficial effects through the JNK signaling pathway on TC cells. These observations demonstrate that LRRK2 silencing promotes TC cell growth inhibition, and facilitates apoptosis and cell cycle arrest. The JNK signaling pathway may serve a crucial role in mediating the anti­carcinogenic activities of downregulated LRRK2 in TC.


Assuntos
Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/biossíntese , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/genética , Sistema de Sinalização das MAP Quinases , Neoplasias da Glândula Tireoide/enzimologia , Neoplasias da Glândula Tireoide/genética , Antracenos/farmacologia , Apoptose/fisiologia , Pontos de Checagem do Ciclo Celular/fisiologia , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Regulação para Baixo , Ativação Enzimática , Humanos , MAP Quinase Quinase 4/antagonistas & inibidores , MAP Quinase Quinase 4/metabolismo , Neoplasias da Glândula Tireoide/patologia , Transfecção
12.
Aquat Toxicol ; 212: 241-246, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31150951

RESUMO

Nowadays, eutrophication is a very popular environmental problem in numerous waters around the world. The main reason of eutrophication is the enrichment of the nutrient, which results in the excessive growth of phytoplankton and some of them are toxic and harmful. Fortunately, some studies have shown that some bivalves can filter the overgrown phytoplankton in water, which may alleviate water eutrophication. However, the physiological effects of toxic cyanobacteria on filter feeding animal have not been clarified very well. In this experiment, digestive enzyme activities in Hyriopsis cumingii exposed to different concentrations of the toxic Microcystis aeruginosa (0, 5 * 105 and 5 *106 cell ml-1) at two dissolved oxygen (DO) levels (6 and 2 mg l-1) for 14 days were investigated. Toxic M. aeruginosa significantly affected all digestive enzyme activities throughout the experiment. At high toxic M. aeruginosa concentration, the activities of cellulase, amylase and lipase in digestive gland and stomach were significantly increased (P<0.05). However, hypoxia reduced the activities of cellulase, amylase and lipase in digestive gland and stomach. Conflicting effects were observed between toxic M. aeruginosa and DO in most digestive enzyme activities during the exposure period. Therefore, it is not conducive for the digestion and absorption of M. aeruginosa in H. cumingii under hypoxic conditions. H. cumingii is tolerant to toxic M. aeruginosa and may remove toxic cyanobacteria from waters under normal DO conditions.


Assuntos
Bivalves/efeitos dos fármacos , Microcistinas/toxicidade , Microcystis/química , Anaerobiose/fisiologia , Animais , Bivalves/enzimologia , Bivalves/fisiologia , Ativação Enzimática/efeitos dos fármacos , Enzimas/metabolismo , Eutrofização , Oxigênio/metabolismo , Poluentes Químicos da Água/toxicidade
13.
Arch Insect Biochem Physiol ; 101(4): e21586, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31180597

RESUMO

This study examined the effect of two natural toxins (a venom from the parasitic wasp Habrobracon hebetor and destruxin A from the entomopathogenic fungus Metarhizium anisopliae), and one pathogen (the entomopathogenic fungus Isaria fumosorosea) on the activity of basic digestive enzymes in the midgut of the cockroach Periplaneta americana. Simultaneously, the role of adipokinetic hormones (AKH) in the digestive processes was evaluated. The results showed that all tested toxins/pathogens elicited stress responses when applied into the cockroach body, as documented by an increase of AKH level in the central nervous system. The venom from H. hebetor showed no effect on digestive enzyme activities in the ceca and midgut in vitro. In addition, infection by I. fumosorosea caused a decrease in activity of all enzymes in the midgut and a variable decrease in activity in the ceca; application of AKHs did not reverse the inhibition. Destruxin A inhibited the activity of all enzymes in the midgut but none in the ceca in vitro; application of AKHs did reverse this inhibition, and no differences between both cockroach AKHs were found. Overall, the results demonstrated the variable effect of the tested toxins/pathogens on the digestive processes of cockroaches as well as the variable ability of AKH to counteract these effects.


Assuntos
Depsipeptídeos/toxicidade , Hormônios de Inseto/farmacologia , Oligopeptídeos/farmacologia , Periplaneta/efeitos dos fármacos , Ácido Pirrolidonocarboxílico/análogos & derivados , Venenos de Vespas/toxicidade , Animais , Ativação Enzimática , Trato Gastrointestinal/enzimologia , Periplaneta/enzimologia , Ácido Pirrolidonocarboxílico/farmacologia
14.
Sheng Wu Gong Cheng Xue Bao ; 35(5): 795-804, 2019 May 25.
Artigo em Chinês | MEDLINE | ID: mdl-31222998

RESUMO

The cyanobacterial circadian clock has three relatively independent parts: the input path, the core oscillator, and the output path. The core oscillator is composed of three clock proteins: KaiA, KaiB, and KaiC. The interactions among these three proteins generate a rhythmic signal and convey the input signals to the output signals to maintain the accuracy and stability of the oscillation of downstream signals. Based on the cyanobacterial circadian clock and the structure, function, and interaction of the clock proteins of the core oscillator, combining the recent results from our laboratory, this review summarized the recent progresses of the molecular mechanism of KaiA in regulating KaiC's enzymatic activity, mediating phase reset of the oscillator, and competing with CikA for the binding site of KaiB.


Assuntos
Proteínas de Bactérias , Relógios Circadianos , Peptídeos e Proteínas de Sinalização do Ritmo Circadiano , Cianobactérias , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Relógios Circadianos/genética , Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/metabolismo , Cianobactérias/genética , Ativação Enzimática/genética
15.
Sheng Wu Gong Cheng Xue Bao ; 35(6): 1021-1028, 2019 Jun 25.
Artigo em Chinês | MEDLINE | ID: mdl-31231998

RESUMO

Adenosine 5'-monophosphate-activated protein activated protein kinase (AMPK), a heterotrimeric complex, is an important kinase to regulate glycolipid metabolism and energy balance involved in a variety physiological processes in human body. Many research indicated that the function and activity of AMPK were closely related to inflammation, diabetes and cancers. Recent reports show that inhibition of metformin (a first-line drug) on hepatic glucose in patients with hyperglycemia is associated with AMPK pathway, suggesting that targeting AMPK may be one of the effective strategies for the prevention and treatment of a variety of chronic diseases. Here, we review research progress on the structure, activation and regulation of AMPK in glycolipid metabolism to provide an insight into the basic and clinical research of diabetes therapy.


Assuntos
Metabolismo Energético , Proteínas Quinases Ativadas por AMP , Adenosina , Monofosfato de Adenosina , Ativação Enzimática , Glicolipídeos , Humanos
16.
Chemistry ; 25(44): 10505-10510, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31173420

RESUMO

Precision cell-selective surface glycan remodeling is of vital importance for modulation of cell surface dynamics, tissue-specific imaging, and immunotherapy, but remains an unsolved challenge. Herein, we report a switchable enzymatic accessibility (SEA) strategy for highly specific editing of carbohydrate moieties of interest on the target cell surface. We demonstrate the blocking of enzyme in the inaccessible state with a metal-organic framework (MOF) cage and instantaneous switching to the accessible state through disassembly of MOF. We further show that this level of SEA regulation enables initial guided enzyme delivery to the target cell surface for subsequent cell-specific glycan remodeling, thus providing a temporally and spatially controlled tool for tuning the glycosylation architectures. Terminal galactose/N-acetylgalactosamine (Gal/GalNAc) remodeling and terminal sialic acid (Sia) desialylation have been precisely achieved on target cells even with other cell lines in close spatial proximity. The SEA protocol features a modular and generically adaptable design, a very short protocol duration (ca. 30 min or shorter), and a very high spatial resolving power (ability to differentiate immediately neighboring cell lines).


Assuntos
Membrana Celular/enzimologia , Polissacarídeos/metabolismo , Acetilgalactosamina/química , Acetilgalactosamina/metabolismo , Aptâmeros de Nucleotídeos/química , Biocatálise , Membrana Celular/química , Ativação Enzimática , Galactose/química , Galactose/metabolismo , Galactose Oxidase/antagonistas & inibidores , Galactose Oxidase/metabolismo , Glicosilação , Células Hep G2 , Humanos , Células MCF-7 , Estruturas Metalorgânicas/química , Ácido N-Acetilneuramínico/química , Ácido N-Acetilneuramínico/metabolismo , Imagem Óptica/métodos , Polissacarídeos/química , Propriedades de Superfície
17.
Nat Commun ; 10(1): 2784, 2019 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-31239443

RESUMO

CaMKIIα plays an essential role in decoding Ca2+ signaling in spines by acting as a leaky Ca2+ integrator with the time constant of several seconds. However, the mechanism by which CaMKIIα integrates Ca2+ signals remains elusive. Here, we imaged CaMKIIα-CaM association in single dendritic spines using a new FRET sensor and two-photon fluorescence lifetime imaging. In response to a glutamate uncaging pulse, CaMKIIα-CaM association increases in ~0.1 s and decays over ~3 s. During repetitive glutamate uncaging, which induces spine structural plasticity, CaMKIIα-CaM association did not show further increase but sustained at a constant level. Since CaMKIIα activity integrates Ca2+ signals over ~10 s under this condition, the integration of Ca2+ signal by CaMKIIα during spine structural plasticity is largely due to Ca2+/CaM-independent, autonomous activity. Based on these results, we propose a simple kinetic model of CaMKIIα activation in dendritic spines.


Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Espinhas Dendríticas/enzimologia , Animais , Cálcio/química , Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/química , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Calmodulina/química , Calmodulina/metabolismo , Espinhas Dendríticas/genética , Ativação Enzimática , Ácido Glutâmico/química , Ácido Glutâmico/metabolismo , Cinética , Camundongos , Camundongos Endogâmicos C57BL
18.
J Vet Sci ; 20(3): e12, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31161735

RESUMO

The effects of CYP1A enzyme on the pharmacokinetics of p-acetaminophen were studied in Bactrian camel. Twelve Bactrian camels were divided into 2 groups, then given a single dose of p-acetaminophen only or with the enzyme inhibitor lomefloxacin. Blood samples were collected after different intervals, and p-acetaminophen concentration was determined by high-performance liquid chromatography. Pharmacokinetic parameters were analyzed by Phoenix WinNonLin v.7.0. The results show that lomefloxacin can significantly inhibit Bactrian camel CYP1A enzyme, as evidenced by the prolonged elimination half-life, increased maximum plasma concentration and area under the curve values and the shortened time to peak concentration for p-acetaminophenol in the substrate with inhibitor group. The results lay a foundation for revealing the particular characteristics of the CYP1A enzyme in Bactrian camels.


Assuntos
Acetaminofen/farmacocinética , Camelus , Citocromo P-450 CYP1A1/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Fluoroquinolonas/farmacologia , Acetaminofen/sangue , Animais , Área Sob a Curva , Cromatografia Líquida de Alta Pressão , Ativação Enzimática/efeitos dos fármacos , Meia-Vida
19.
Nature ; 571(7765): 366-370, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31243363

RESUMO

Type 4 P-type ATPases (P4-ATPases) are lipid flippases that drive the active transport of phospholipids from exoplasmic or luminal leaflets to cytosolic leaflets of eukaryotic membranes. The molecular architecture of P4-ATPases and the mechanism through which they recognize and transport lipids have remained unknown. Here we describe the cryo-electron microscopy structure of the P4-ATPase Drs2p-Cdc50p, a Saccharomyces cerevisiae lipid flippase that is specific to phosphatidylserine and phosphatidylethanolamine. Drs2p-Cdc50p is autoinhibited by the C-terminal tail of Drs2p, and activated by the lipid phosphatidylinositol-4-phosphate (PtdIns4P or PI4P). We present three structures that represent the complex in an autoinhibited, an intermediate and a fully activated state. The analysis highlights specific features of P4-ATPases and reveals sites of autoinhibition and PI4P-dependent activation. We also observe a putative lipid translocation pathway in this flippase that involves a conserved PISL motif in transmembrane segment 4 and polar residues of transmembrane segments 2 and 5, in particular Lys1018, in the centre of the lipid bilayer.


Assuntos
ATPases Transportadoras de Cálcio/química , ATPases Transportadoras de Cálcio/metabolismo , Microscopia Crioeletrônica , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimologia , Sítios de Ligação , Transporte Biológico , ATPases Transportadoras de Cálcio/antagonistas & inibidores , ATPases Transportadoras de Cálcio/ultraestrutura , Ativação Enzimática , Bicamadas Lipídicas/metabolismo , Modelos Biológicos , Modelos Moleculares , Fosfatidiletanolaminas/metabolismo , Fosfatos de Fosfatidilinositol/química , Fosfatos de Fosfatidilinositol/metabolismo , Fosfatidilserinas/metabolismo , Domínios Proteicos , Proteínas de Saccharomyces cerevisiae/antagonistas & inibidores , Proteínas de Saccharomyces cerevisiae/ultraestrutura
20.
Cell Mol Biol Lett ; 24: 32, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31143210

RESUMO

Objective: Peritoneal fibrosis remains a serious complication of long-term peritoneal dialysis (PD) leading to peritoneal membrane ultrafiltration failure. Epithelial-mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs) is a key process of peritoneal fibrosis. Curcumin has been previously shown to inhibit EMT of renal tubular epithelial cells and prevent renal fibrosis. There are only limited reports on inhibition of PMCs-EMT by curcumin. This study aimed to investigate the effect of curcumin on the regulation of EMT and related pathway in PMCs treated with glucose-based PD. Methods: EMT of human peritoneal mesothelial cells (HMrSV5) was induced with glucose-based peritoneal dialysis solutions (PDS). Cells were divided into a control group, PDS group, and PDS group receiving varied concentrations of curcumin. Cell Counting Kit-8 (CCK-8) assay was used to measure cell viability, and a transwell migration assay was used to verify the capacity of curcumin to inhibit EMT in HMrSV5 cells. Real-time quantitative PCR and western blot were used to detect the expression of genes and proteins associated with the EMT. Results: High glucose PDS decreased cell viability and increased migratory capacity. Curcumin reversed growth inhibition and migration capability of human peritoneal mesothelial cells (HPMCs). In HMrSV5 cells, high glucose PDS also decreased expression of epithelial markers, and increased expression of mesenchymal markers, a characteristic of EMT. Real-time RT-PCR and western blot revealed that, compared to the 4.25% Dianeal treated cells, curcumin treatment resulted in increased expression of E-cadherin (epithelial marker), and decreased expression of α-SMA (mesenchymal markers) (P < 0.05). Furthermore, curcumin reduced mRNA expression of two extracellular matrix protein, collagen I and fibronectin. Curcumin also reduced TGF-ß1 mRNA and supernatant TGF-ß1 protein content in the PDS-treated HMrSV5 cells (P < 0.05). Furthermore, it significantly reduced protein expression of p-TAK1, p-JNK and p-p38 in PDS-treated HMrSV5 cells. Conclusions: Our results demonstrate that curcumin showed an obvious protective effect on PDS-induced EMT of HMrSV5 cells and suggest implication of the TAK1, p38 and JNK pathway in mediating the effects of curcumin in EMT of MCs.


Assuntos
Curcumina/farmacologia , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Epitélio/patologia , MAP Quinase Quinase Quinases/metabolismo , Peritônio/patologia , Biomarcadores/metabolismo , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Transição Epitelial-Mesenquimal/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/toxicidade , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Diálise Peritoneal , Fosforilação/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA