Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 72
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Mol Cell ; 83(16): 3027-3040.e11, 2023 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-37541260

RESUMO

The mechanistic target of rapamycin complex 1 (mTORC1) regulates metabolism and cell growth in response to nutrient levels. Dysregulation of mTORC1 results in a broad spectrum of diseases. Glucose is the primary energy supply of cells, and therefore, glucose levels must be accurately conveyed to mTORC1 through highly responsive signaling mechanisms to control mTORC1 activity. Here, we report that glucose-induced mTORC1 activation is regulated by O-GlcNAcylation of Raptor, a core component of mTORC1, in HEK293T cells. Mechanistically, O-GlcNAcylation of Raptor at threonine 700 facilitates the interactions between Raptor and Rag GTPases and promotes the translocation of mTOR to the lysosomal surface, consequently activating mTORC1. In addition, we show that AMPK-mediated phosphorylation of Raptor suppresses Raptor O-GlcNAcylation and inhibits Raptor-Rags interactions. Our findings reveal an exquisitely controlled mechanism, which suggests how glucose coordinately regulates cellular anabolism and catabolism.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Complexos Multiproteicos , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Células HEK293 , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Complexos Multiproteicos/metabolismo , Proteína Regulatória Associada a mTOR/genética , Proteína Regulatória Associada a mTOR/metabolismo , Fosforilação
2.
Mol Cell ; 82(4): 770-784.e9, 2022 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-35114100

RESUMO

The mTOR complex 1 (mTORC1) is an essential metabolic hub that coordinates cellular metabolism with the availability of nutrients, including amino acids. Sestrin2 has been identified as a cytosolic leucine sensor that transmits leucine status signals to mTORC1. In this study, we identify an E3 ubiquitin ligase RING finger protein 167 (RNF167) and a deubiquitinase STAMBPL1 that function in concert to control the polyubiquitination level of Sestrin2 in response to leucine availability. Ubiquitination of Sestrin2 promotes its interaction with GATOR2 and inhibits mTORC1 signaling. Bioinformatic analysis reveals decreased RNF167 expression and increased STAMBPL1 expression in gastric and colorectal tumors. Knockout of STAMBPL1 or correction of the heterozygous STAMBPL1 mutation in a human colon cancer cell line suppresses xenograft tumor growth. Lastly, a cell-permeable peptide that blocks the STAMBPL1-Sestrin2 interaction inhibits mTORC1 and provides a potential option for cancer therapy.


Assuntos
Neoplasias Colorretais/enzimologia , Peptídeo Hidrolases/metabolismo , Neoplasias Gástricas/enzimologia , Serina-Treonina Quinases TOR/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Animais , Células CACO-2 , Proliferação de Células , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Células HCT116 , Células HEK293 , Humanos , Leucina/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos Endogâmicos BALB C , Camundongos Nus , Mutação , Proteínas Nucleares/metabolismo , Peptídeo Hidrolases/genética , Transdução de Sinais , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia , Carga Tumoral , Ubiquitina-Proteína Ligases/genética , Ubiquitinação
3.
Plant Cell Environ ; 47(7): 2410-2425, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38517937

RESUMO

Bainong sterility (BNS) is a thermo-sensitive genic male sterile wheat line, characterised by anther fertility transformation in response to low temperature (LT) stress during meiosis, the failure of vacuole decomposition and the absence of starch accumulation in sterile bicellular pollen. Our study demonstrates that the late microspore (LM) stage marks the transition from the anther growth to anther maturation phase, characterised by the changes in anther structure, carbohydrate metabolism and the main transport pathway of sucrose (Suc). Fructan is a main storage polysaccharide in wheat anther, and its synthesis and remobilisation are crucial for anther development. Moreover, the process of pollen amylogenesis and the fate of the large vacuole in pollen are closely intertwined with fructan synthesis and remobilisation. LT disrupts the normal physiological metabolism of BNS anthers during meiosis, particularly affecting carbohydrate metabolism, thus determining the fate of male gametophytes and pollen abortion. Disruption of fructan synthesis and remobilisation regulation serves as a decisive event that results in anther abortion. Sterile pollen exhibits common traits of pollen starvation and impaired starch accumulation due to the inhibition of apoplastic transport starting from the LM stage, which is regulated by cell wall invertase TaIVR1 and Suc transporter TaSUT1.


Assuntos
Metabolismo dos Carboidratos , Flores , Infertilidade das Plantas , Pólen , Triticum , Triticum/genética , Triticum/crescimento & desenvolvimento , Triticum/metabolismo , Triticum/fisiologia , Infertilidade das Plantas/genética , Pólen/crescimento & desenvolvimento , Pólen/genética , Pólen/metabolismo , Flores/crescimento & desenvolvimento , Flores/genética , Flores/fisiologia , Flores/metabolismo , Amido/metabolismo , Sacarose/metabolismo , Frutanos/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética
4.
Aesthetic Plast Surg ; 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38772942

RESUMO

BACKGROUND: Hypertrophic osteoarthropathy (HOA) is a rare and intricate hereditary disease. The appearance and functional deformity of the forehead caused by thickened folds are the main clinical manifestations of patients with hypertrophic osteoarthropathy. The cause of this disease is still unknown. Currently, surgical treatment has become one of the best strategies, mainly for improving the appearance of the forehead. There has been no literature report on the use of "W"-shaped skin flap resection for thickened forehead skin in patients with hypertrophic osteoarthropathy. METHODS: All cases of hypertrophic osteoarthropathy in our department in the last 7 years, and previous literature on hypertrophic osteoarthropathy, were reviewed. RESULTS: A total of 5 cases of hypertrophic osteoarthropathy in our department (mean age 21 years, all male patients) were reviewed. All patients underwent open surgery to remove the thickened skin on the forehead or the wrinkles and gyrus-shaped scalp. The jagged skin tissue was removed (8-9) cm × (1-2.5) cm × 0.5 cm. The folds and thickness of the frontal skin of the patients were greatly improved after the operation. Patient satisfaction with the treatment outcomes was unanimous. However, one case experienced a postoperative wound infection during follow-up. The utilization of the "W"-shaped excision technique allowed for the maximal removal of excessively diseased tissue, thereby facilitating a smoother resolution of the depression. CONCLUSIONS: A total of 5 cases of hypertrophic osteoarthropathy were treated in our department, and all of them underwent frontal skin "W"-shaped excision, which was safe, feasible, and practical, and the postoperative results were satisfactory. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

5.
Phytopathology ; 113(3): 497-507, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36346372

RESUMO

Late blight and powdery mildew are two widespread tomato diseases caused by Phytophthora infestans and Oidium neolycopersici, respectively, which reduce the quantity and quality of tomato. MicroRNAs (miRNAs) play critical roles in tomato resistance to various pathogens. Investigating the function of miRNAs is of great significance in controlling tomato diseases. To identify potential miRNAs involved in the interaction of tomato with P. infestans or O. neolycopersici, we analyzed the expression profiles of small RNAs in tomato leaves infected with these two pathogens using RNA-seq technology. A total of 330 and 288 miRNAs exhibited differences in expression levels after exposure to P. infestans and O. neolycopersici, respectively. One hundred and forty-six commonly differentially expressed (DE) miRNAs responsive to P. infestans and O. neolycopersici infestation were detected, including 10 commonly known conserved DE miRNAs and 136 novel miRNAs. Among these known DE miRNAs, sly-miR397 was strongly downregulated in response to P. infestans or O. neolycopersici infection. Silencing of sly-miR397 resulted in enhanced tolerance to the pathogens, whereas overexpression of sly-miR397 showed increased susceptibility. Furthermore, changes in sly-miR397 expression could also affect expression levels of pathogenesis-related genes and reactive oxygen species-scavenging genes, leading to altered necrotic cells and H2O2 levels. In addition, the number of lateral branches significantly changed in transgenic plants. Taken together, our results provide potential miRNA resources for further research of miRNA-disease associations and indicates that sly-miR397 acts as a negative regulator of disease resistance and influences lateral branch development in tomato.


Assuntos
MicroRNAs , Phytophthora infestans , Solanum lycopersicum , Solanum lycopersicum/genética , Phytophthora infestans/genética , Peróxido de Hidrogênio , Doenças das Plantas/genética , MicroRNAs/genética , MicroRNAs/metabolismo
6.
BMC Microbiol ; 22(1): 275, 2022 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-36380285

RESUMO

BACKGROUND: Wickerhamomyces anomalus (W. anomalus) is a kind of non-Saccharomyces yeast that has a variety of unique physiological characteristics and metabolic features and is widely used in many fields, such as food preservation, biomass energy, and aquaculture feed protein production. However, the mechanism of W. anomalus response to ethanol stress is still unclear, which greatly limits its application in the production of ethanol beverages and ethanol fuels. Therefore, we checked the effects of ethanol stress on the morphology, the growth, and differentially expressed genes (DEGs) and metabolites (DEMs) of W. anomalus. RESULTS: High concentrations of ethanol (9% ethanol and 12% ethanol) remarkably inhibited the growth of W. anomalus. Energy metabolism, amino acid metabolism, fatty acids metabolism, and nucleic acid metabolism were significantly influenced when exposing to 9% ethanol and 12% ethanolstress, which maybe universal for W. anomalus to response to different concentrations of ethanol stressl Furthermore, extracellular addition of aspartate, glutamate, and arginine significantly abated ethanol damage and improved the survival rate of W. anomalus. CONCLUSIONS: The results obtained in this study provide insights into the mechanisms involved in W. anomalus response to ethanol stress. Therefore, new strategies can be realized to improve the ethanol tolerance of W. anomalus through metabolic engineering.


Assuntos
Etanol , Saccharomycetales , Etanol/farmacologia , Etanol/metabolismo , Transcriptoma , Saccharomycetales/genética , Saccharomycetales/metabolismo , Leveduras
7.
Bioorg Med Chem ; 73: 117033, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-36202064

RESUMO

Targeted protein degradation using proteolysis-targeting chimeras (PROTACs) has emerged as an effective strategy for drug discovery, given their unique advantages over target protein inhibition. The bromodomain and extra-terminal (BET) family proteins play a key role in regulating oncogene expression and are considered attractive therapeutic targets for cancer therapy. Considering the therapeutic potential of BET proteins in cancer and the marked attractiveness of PROTACs, BET-targeting PROTACs have been extensively pursued. Recently, BET-targeting PROTACs based on new E3 ligases and novel strategies, such as light-activated, macrocyclic, folate-caged, aptamer-PROTAC conjugation, antibody-coupling, and autophagy-targeting strategies, have emerged. In the present review, we provide a comprehensive summary of advances in BET-targeting PROTACs.


Assuntos
Neoplasias , Humanos , Ácido Fólico , Neoplasias/tratamento farmacológico , Proteólise , Ubiquitina-Proteína Ligases/metabolismo
8.
Eur J Nutr ; 61(1): 23-35, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34075433

RESUMO

OBJECTIVE: Observational studies have shown that vitamin D levels are inversely related to ulcerative colitis activity, yet evidence from population interventions remains inconsistent. We conducted a systematic review and meta-analysis of randomized-controlled trials to clarify the effect of vitamin D on blood markers in patients with ulcerative colitis. METHODS: The PubMed, Cochrane Library, Embase, CNKI, VIP, and Wanfang databases were searched for studies published before June 2020. Information was collected regarding serum vitamin D levels, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), and Ca (calcium), and parathyroid hormone (PTH), and ulcerative colitis disease activity index (UCDAI) research data. RESULTS: Seven studies (n = 539) were included in the meta-analysis. Vitamin D supplementation resulted in significant improvements in the serum vitamin D levels (standardized mean difference (SMD) = 0.69, 95% CI (0.36, 1.03), P < 0.001), ESR (weighted mean difference (WMD) = - 1.10, 95% CI (- 1.97, - 0.24), P = 0.01), CRP (SMD = - 0.43, 95% CI (- 0.67, - 0.20), P = 0.0003), and Ca (SMD = 0.92, 95% CI (0.09, 1.74), P = 0.03) but not in other outcomes. According to subgroup analysis, supplementation with vitamin D at a dose of ≥ 300,000 IU/day can improve serum vitamin D levels. Supplementation with a sufficient dose of vitamin D in a short period of time can also improve serum vitamin D levels. According to GRADE method evaluation, the evidence quality was classified as low for the Serum Vitamin D Level and ESR, and very low for the CRP, PTH, Ca, and UCDAI. CONCLUSIONS: Compared with placebo control interventions, vitamin D supplementation seemed to be an effective intervention for patients with ulcerative colitis. Different doses of vitamin D and durations of intervention produce different effects. However, due to the limitation of the quality of the included studies, the above conclusions still need to be verified by more high-quality studies and weak clinical recommendations.


Assuntos
Colite Ulcerativa , Suplementos Nutricionais , Vitamina D/uso terapêutico , Colite Ulcerativa/tratamento farmacológico , Humanos , Vitamina D/sangue , Vitaminas/uso terapêutico
9.
Molecules ; 27(21)2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36364306

RESUMO

Ginkgo tea and ginkgo wine are two familiar Ginkgo biloba leaf extract (GBE) drinks in the form of dietary supplements (DS) used for healthcare in east Asia. Nevertheless, a comprehensive evaluation of their safety and efficacy is still lacking. In this study, GBE drinks were prepared from naturally newly senescent yellow leaves (YL) and green leaves (GL) in autumn. Their total flavonoids, antioxidant capacity and prescribed ingredients were investigated. In brief, the proportions of total flavonoids, total flavonol glycosides (TFs), total terpene trilactones (TTLs) and ginkgolic acids in the GBE drinks all did not meet the standards of worldwide pharmacopoeias. Specifically, the levels of TFs in the ginkgo tea prepared from YL were significantly higher than that prepared from GL. Further analyses revealed a substandard ratio of isorhamnetin/quercetin and an accumulation of leaf-age-related compounds, which were both unqualified. The proportions of specific TTLs varied between the ginkgo tea and ginkgo wine, although no significant differences were detected in terms of the total levels of TTLs. Noticeably, numerous biflavones and thousands of times over the limiting concentration of ginkgolic acids, including newly identified types, were only detected in ginkgo wine. Finally, the use of the GBE drinks as DSs was comprehensively evaluated according to the acceptable daily intake. This study showed the limited healthcare effects of GBE drinks despite their powerful antioxidant capacity.


Assuntos
Antioxidantes , Ginkgo biloba , Antioxidantes/farmacologia , Antioxidantes/análise , Extratos Vegetais/farmacologia , Suplementos Nutricionais/análise , Flavonoides/farmacologia , Terpenos/análise , Chá , Folhas de Planta/química
10.
Zhongguo Zhong Yao Za Zhi ; 47(2): 547-556, 2022 Jan.
Artigo em Zh | MEDLINE | ID: mdl-35178999

RESUMO

This study aims to evaluate the methodological and reporting quality of diagnosis and treatment guidelines for hyperuricemia as well as the expert consensuses and promote the understanding and application of the diagnosis and treatment guidelines for hyperuricemia. With "hyperuricemia" "guidelines" "consensus" "recommendations" as the key words in titles, the authors searched for the published clinical guidelines on hyperuricemia in Chinese against CNKI, Wanfang, VIP, Medlive and the official website of the industry association. The retrieval time limit was until May 31, 2021. The appraisal of guidelines for research and evaluation Ⅱ(AGREEⅡ) and the reporting items for practice guidelines in health care(RIGHT) were employed to evaluate the methodological quality and reporting quality of 14 guidelines/consensuses included. The average scores of the guidelines/consensuses were 80.85%(48.61%-98.61%) for the domain of scope and purpose, 34.52%(0-69.44%) for the domain of stakeholder involvement, 35.53%(6.25%-92.19%) for the domain of rigor of development, 55.85%(23.61%-86.11%) for the domain of clarity of presentation, 26.19%(0-76.04%) for the domain of applicability, and 21.42%(0-50.00%) for the domain of editorial independence. Nine guidelines/consensuses were of medium overall quality with grade B recommendation, and five guidelines/consensuses were of poor quality with grade C recommendation. The RIGHT classified the fourteen guidelines/consensuses into one of high reporting quality, three of medium reporting quality, and ten of low reporting quality. The results of this study indicate that the standardization and rigor of the methodological quality and the reporting quality of the clinical guidelines/consensuses for hyperuricemia in China remain to be strengthened.


Assuntos
Hiperuricemia , China , Consenso , Humanos , Hiperuricemia/tratamento farmacológico , Publicações , Padrões de Referência
11.
BMC Plant Biol ; 21(1): 545, 2021 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-34800968

RESUMO

BACKGROUND: Virus-induced gene silencing (VIGS) is one of the most convenient and powerful methods of reverse genetics. In vitro-inoculation of plant virus is an important method for studying the interactions between viruses and plants. Agrobacterium-based infiltration has been widely adopted as a tool for VIGS and in vitro-inoculation of plant virus. Most agrobacterium-based infiltration methods applied to VIGS and virus inoculation have the characteristics of low transformation efficiencies, long plant growth time, large amounts of plant tissue, large test spaces, and complex preparation procedures. Therefore, a rapid, simple, economical, and highly efficient VIGS and virus inoculation method is in need. Previous studies have shown that the selection of suitable plant tissues and inoculation sites is the key to successful infection. RESULTS: In this study, Tobacco rattle virus (TRV) mediated VIGS and Tomato yellow leaf curl virus (TYLCV) for virus inoculation were developed in tomato plants based on the agrobacterium tumefaciens-based infiltration by injection of the no-apical-bud stem section (INABS). The no-apical-bud stem section had a "Y- type" asymmetric structure and contained an axillary bud that was about 1-3 cm in length. This protocol provides high transformation (56.7%) and inoculation efficiency (68.3%), which generates VIGS transformants or diseased plants in a very short period (8 dpi). Moreover, it greatly reduces the required experimental space. This method will facilitate functional genomic studies and large-scale disease resistance screening. CONCLUSIONS: Overall, a rapid, simple, and highly efficient method for VIGS and virus inoculation by INABS was developed in tomato. It was reasonable to believe that it can be used as a reference for the other virus inoculation methods and for the application of VIGS to other crops (such as sweet potato, potato, cassava and tobacco) that develop axillary buds and can survive from cuttings.


Assuntos
Agrobacterium/patogenicidade , Begomovirus/patogenicidade , Inativação Gênica , Melhoramento Vegetal/métodos , Vírus de Plantas/patogenicidade , Solanum lycopersicum/crescimento & desenvolvimento , Solanum lycopersicum/genética , Produtos Agrícolas/genética , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/virologia , Regulação da Expressão Gênica de Plantas , Solanum lycopersicum/virologia , Doenças das Plantas/virologia
12.
J Gastroenterol Hepatol ; 36(11): 3015-3026, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34342044

RESUMO

OBJECTIVES: The therapeutic effect of acupuncture treatments (AT) on functional gastrointestinal disorders (FGIDs) is contentious. A meta-analysis was conducted to assess the efficacy and safety of acupuncture for FGIDs. METHODS: The Cochrane Library, EMBASE, PUBMED, Web of Science, Wanfang Database, China National Knowledge Infrastructure, and VIP Database were searched through December 31, 2019 with no language restrictions. Risk ratio (RR) with 95% confidence interval (CI) was calculated to determine the improvement in symptom severity after treatment. RESULTS: A total of 61 randomized controlled trials (RCTs) on FGIDs were included. The pooled results illustrated the following: compared to pharmacotherapy (RR 1.13, 95% CI 1.09-1.17), placebo acupuncture (RR 1.69, 95% CI 1.37-2.08), no specific treatment (RR 1.86, 95% CI 1.31-2.62), and AT as an adjuvant intervention to other active treatments (RR 1.25, 95% CI 1.21-1.30), AT had more favorable improvements in symptom severity; sub-group analysis results classified according to functional dyspepsia, irritable bowel syndrome, and functional constipation also supported this finding; and the incidence of adverse events was lower in AT than in other treatments (RR 0.75, 95% CI 0.56-0.99). CONCLUSIONS: This meta-analysis found that AT was significantly associated with relief of FGIDs symptoms; however, the evidence level was moderate or low. Further data from rigorously designed and well powered RCTs are needed to verify the effectiveness and safety of AT as a FGIDs treatment. PROSPERO PROTOCOL NUMBER: CRD42020169508.


Assuntos
Terapia por Acupuntura , Gastroenteropatias , Constipação Intestinal/terapia , Dispepsia/terapia , Gastroenteropatias/terapia , Humanos , Síndrome do Intestino Irritável/terapia , Ensaios Clínicos Controlados Aleatórios como Assunto
13.
Phytopathology ; 111(12): 2309-2316, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34058858

RESUMO

Fusarium head blight (FHB), mainly caused by Fusarium graminearum, has become one of the most serious diseases that damage wheat. The TaPFT (pore-forming toxin-like) and TaHRC (histidine-rich calcium-binding protein) genes at the quantitative trait locus Fhb1 were identified to confer resistance to FHB in the wheat cultivar Sumai 3. In this study, a wheat ricin B-like lectin gene (designated TaRBL) that interacted with TaPFT was isolated by a yeast two-hybrid screen of a wheat cDNA library. A yeast two-hybrid and bimolecular fluorescence complementation study further verified that TaRBL interacted with TaPFT but not with TaHRC. Gene expression studies showed that upon F. graminearum infection, TaRBL expression was upregulated in resistant cultivars but downregulated in susceptible cultivars. Furthermore, knockdown of TaRBL expression by barley stripe mosaic virus-induced gene silencing significantly reduced the resistance of wheat to FHB in both the resistant cultivar Sumai 3 and the susceptible cultivar Jimai 22. Thus, we conclude that TaRBL encodes a ricin B-like lectin protein that interacts with TaPFT and is involved in resistance to FHB in wheat.


Assuntos
Fusarium , Ricina , Resistência à Doença/genética , Doenças das Plantas , Locos de Características Quantitativas , Triticum/genética
14.
Analyst ; 144(2): 656-662, 2019 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-30484788

RESUMO

In this paper, we have presented a novel strategy to fabricate Fe-doped carbon quantum dots (Fe-CQDs) for dopamine sensing applications. The Fe-CQDs are obtained by one step hydrothermal carbonization, using ethylenediamine tetraacetic acid salts and ferric nitrate as the carbon and iron source, which simultaneously incorporates Fe (dopamine-bonding site) and luminescent carbon quantum dots (fluorophores). The added dopamine containing catechol groups might form complexes with Fe ions (doped in CQDs) due to coordination. Subsequently, dopamine was oxidized to generate dopamine-quinone (a known potent electron acceptor) species by ambient O2. Thus, the coordination induced dopamine in proximity to the CQDs, which provided favourable electron acceptors in close proximity to the CQDs and produced high quenching efficiencies. Such fluorescence responses can be used for well quantifying dopamine in the range of 0.01-50 µM with a detection limit of 5 nM (S/N = 3). The proposed sensing system has been successfully used for the assay of dopamine in human urine samples. Preliminary cell image study indicates that the obtained Fe-CQDs possess high photostability and low cytotoxicity, which make them promising for biological applications.


Assuntos
Dopamina/análise , Pontos Quânticos/química , Espectrometria de Fluorescência/métodos , Carbono/química , Sobrevivência Celular/efeitos dos fármacos , Dopamina/urina , Feminino , Células HeLa , Humanos , Ferro/química , Limite de Detecção , Microscopia Confocal/métodos , Pontos Quânticos/toxicidade , Reprodutibilidade dos Testes , Adulto Jovem
15.
Plant Physiol ; 173(2): 944-955, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27913740

RESUMO

Cuticular waxes are complex mixtures of very-long-chain fatty acids (VLCFAs) and their derivatives, forming a natural barrier on aerial surfaces of terrestrial plants against biotic and abiotic stresses. In VLCFA biosynthesis, ß-ketoacyl-CoA synthase (KCS) is the key enzyme, catalyzing the first reaction in fatty acid elongation and determining substrate specificity. We isolated a rice (Oryza sativa) wax crystal-sparse leaf 4 (WSL4) gene using a map-based cloning strategy. WSL4 is predicted to encode a KCS, a homolog of Arabidopsis (Arabidopsis thaliana) CER6. Complementation of the mutant wsl4-1 with WSL4 genomic DNA rescued the cuticular wax-deficient phenotype, confirming the function of WSL4 The load of wax components longer than 30 carbons (C30) and C28 were reduced markedly in wsl4-1 and wsl4-2 mutants, respectively. Overexpression of WSL4 increased the cuticular wax load in rice leaves. We further isolated a cofactor of WSL4, OsCER2, a homolog of Arabidopsis CER2, by coimmunoprecipitation and confirmed their physical interaction by split-ubiquitin yeast two-hybrid experiments. Expression of WSL4 alone in elo3 yeast cells resulted in increased C24 but did not produce VLCFAs of greater length, whereas expressing OsCER2 alone showed no effect. Coexpression of WSL4 and OsCER2 in elo3 yeast cells yielded fatty acids up to C30. OsCER2 with a mutated HxxxD motif (H172E, D176A, and D176H) interrupted its interaction with WSL4 and failed to elongate VLCFAs past C24 when expressed with WSL4 in elo3 yeast cells. These results demonstrated that WSL4 was involved in VLCFA elongation beyond C22 and that elongation beyond C24 required the participation of OsCER2.


Assuntos
3-Oxoacil-(Proteína de Transporte de Acila) Sintase/metabolismo , Coenzimas/metabolismo , Oryza/enzimologia , Epiderme Vegetal/metabolismo , Folhas de Planta/enzimologia , Proteínas de Plantas/metabolismo , Ceras/metabolismo , Alelos , Motivos de Aminoácidos , Sequência de Aminoácidos , Mapeamento Cromossômico , Clonagem Molecular , Sequência Conservada/genética , Ácidos Graxos/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Técnicas de Inativação de Genes , Mutação/genética , Folhas de Planta/genética , Proteínas de Plantas/química , Proteínas de Plantas/genética , Ligação Proteica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Saccharomyces cerevisiae/metabolismo , Frações Subcelulares
16.
Bioorg Med Chem ; 26(23-24): 6000-6014, 2018 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-30448189

RESUMO

LSD1 is implicated in a number of malignancies and has emerged as an exciting target. As part of our sustained efforts to develop novel reversible LSD1 inhibitors for epigenetic therapy of cancers, in this study, we reported a series of stilbene derivatives and evaluated their LSD1 inhibitory activities, obtaining several compounds as potent LSD1 inhibitors with IC50 values in submicromolar range. Enzyme kinetics studies and SPR assay suggested that compound 8c, the most active LSD1 inhibitor (IC50 = 283 nM), potently inhibited LSD1 in a reversible and FAD competitive manner. Consistent with the kinetics data, molecular docking showed that compound 8c can be well docked into the FAD binding site of LSD1. Flow cytometry analysis showed that compound 8c was capable of up-regulating the expression of the surrogate cellular biomarker CD86 in THP-1 human leukemia cells, suggesting the ability to block LSD1 activity in cells. Compound 8c showed good inhibition against THP-1 and MOLM-13 cells with IC50 values of 5.76 and 8.34 µM, respectively. Moreover, compound 8c significantly inhibited colony formation of THP-1 cells dose dependently.


Assuntos
Antineoplásicos/farmacologia , Desenho de Fármacos , Inibidores Enzimáticos/farmacologia , Histona Desmetilases/antagonistas & inibidores , Leucemia Mieloide Aguda/tratamento farmacológico , Estilbenos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Histona Desmetilases/metabolismo , Humanos , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Simulação de Acoplamento Molecular , Estrutura Molecular , Estilbenos/síntese química , Estilbenos/química , Relação Estrutura-Atividade , Células THP-1
17.
Tumour Biol ; 37(4): 5239-45, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26555544

RESUMO

Purified white polysaccharide (PPW) is a homogenous polysaccharide isolated from pumpkin, with an average molecular weight of 34 kDa. In this study, we aimed at examining the anti-proliferative activity of PPW against hepatocellular carcinoma (HCC) HepG2 cells and the underlying mechanisms. We found that PPW-induced inhibition of cell proliferation in HepG2 cells was associated with the induction of apoptosis. Exposure of HepG2 cells to PPW (100, 200, and 400 µg/mL) resulted in a loss of mitochondrial membrane potential (Δψm) and the release of cytochrome c from the mitochondria to the cytosol. Also, Western blot analysis revealed dose-dependent increase of pro-apoptotic Bax protein and decrease of anti-apoptotic Bcl-2 protein in PPW-treated cells. Besides, caspase-9 and caspase-3 activities were also enhanced in HepG2 cells followed by PPW treatment. Additionally, the cleavage of poly (ADP-ribose) polymerase (PARP) was observed in PPW-treated HepG2 cells, which altogether account for apoptotic cell death. These results suggested that PPW-induced apoptosis involved a caspase-3-mediated mitochondrial pathway and may have potential as a cancer chemopreventive and therapeutic agent for the prevention and treatment of HCC.


Assuntos
Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Polissacarídeos/administração & dosagem , Apoptose/efeitos dos fármacos , Carcinoma Hepatocelular/patologia , Caspase 3/genética , Cucurbita/química , Células Hep G2 , Humanos , Neoplasias Hepáticas/patologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Polissacarídeos/química , Transdução de Sinais/efeitos dos fármacos
18.
Clin Endocrinol (Oxf) ; 80(3): 425-31, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23869585

RESUMO

OBJECTIVE: Previous studies have indicated that berberine is an effective insulin sensitizer with comparable activity to metformin (Diabetes 2006, 55, 2256). Reduced insulin sensitivity is reportedly a factor adversely affecting the outcome of IVF in patients with polycystic ovary syndrome (PCOS) (Human Reproduction 2006, 21, 1416). Our objective was to evaluate the clinical, metabolic and endocrine effects of berberine vs metformin in PCOS women scheduled for IVF treatment and to explore the potential benefits to the IVF process. DESIGN: We performed a prospective study in 150 infertile women with PCOS undergoing IVF treatment. Patients were randomized to receive berberine, metformin or placebo tablets for 3 months before ovarian stimulation. MEASUREMENTS: The clinical, endocrine, metabolic parameters and the outcome of IVF. RESULTS: Compared with placebo, greater reductions in total testosterone, free androgen index, fasting glucose, fasting insulin and HOMA-IR, and increases in SHBG, were observed in the berberine and metformin groups. Three months of treatment with berberine or metformin before the IVF cycle increased the pregnancy rate and reduced the incidence of severe ovarian hyperstimulation syndrome. Furthermore, treatment with berberine, in comparison with metformin, was associated with decreases in BMI, lipid parameters and total FSH requirement, and an increase in live birth rate with fewer gastrointestinal adverse events. CONCLUSIONS: Berberine and metformin treatments prior to IVF improved the pregnancy outcome by normalizing the clinical, endocrine and metabolic parameters in PCOS women. Berberine has a more pronounced therapeutic effect and achieved more live births with fewer side effects than metformin.


Assuntos
Berberina/uso terapêutico , Fertilização in vitro , Infertilidade Feminina/terapia , Síndrome do Ovário Policístico/terapia , Adulto , Feminino , Humanos , Hipoglicemiantes/uso terapêutico , Infertilidade Feminina/complicações , Infertilidade Feminina/epidemiologia , Metformina/uso terapêutico , Síndrome de Hiperestimulação Ovariana/epidemiologia , Síndrome de Hiperestimulação Ovariana/prevenção & controle , Indução da Ovulação/métodos , Síndrome do Ovário Policístico/complicações , Síndrome do Ovário Policístico/epidemiologia , Gravidez , Taxa de Gravidez , Adulto Jovem
19.
Neural Netw ; 175: 106315, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38626618

RESUMO

Pre-trained Language Model (PLM) is nowadays the mainstay of Unsupervised Sentence Representation Learning (USRL). However, PLMs are sensitive to the frequency information of words from their pre-training corpora, resulting in anisotropic embedding space, where the embeddings of high-frequency words are clustered but those of low-frequency words disperse sparsely. This anisotropic phenomenon results in two problems of similarity bias and information bias, lowering the quality of sentence embeddings. To solve the problems, we fine-tune PLMs by leveraging the frequency information of words and propose a novel USRL framework, namely Sentence Representation Learning with Frequency-induced Adversarial tuning and Incomplete sentence filtering (Slt-fai). We calculate the word frequencies over the pre-training corpora of PLMs and assign words thresholding frequency labels. With them, (1) we incorporate a similarity discriminator used to distinguish the embeddings of high-frequency and low-frequency words, and adversarially tune the PLM with it, enabling to achieve uniformly frequency-invariant embedding space; and (2) we propose a novel incomplete sentence detection task, where we incorporate an information discriminator to distinguish the embeddings of original sentences and incomplete sentences by randomly masking several low-frequency words, enabling to emphasize the more informative low-frequency words. Our Slt-fai is a flexible and plug-and-play framework, and it can be integrated with existing USRL techniques. We evaluate Slt-fai with various backbones on benchmark datasets. Empirical results indicate that Slt-fai can be superior to the existing USRL baselines.


Assuntos
Idioma , Aprendizado de Máquina não Supervisionado , Humanos , Redes Neurais de Computação , Processamento de Linguagem Natural , Algoritmos
20.
J Adv Res ; 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38555000

RESUMO

BACKGROUND: Atherosclerosis is a chronic and complex disease caused by lipid disorder, inflammation, and other factors. It is closely related to cardiovascular diseases, the chief cause of death globally. Peroxisome proliferator-activated receptors (PPARs) are valuable anti-atherosclerosis targets that showcase multiple roles at different pathological stages of atherosclerosis and for cell types at different tissue sites. AIM OF REVIEW: Considering the spatial and temporal characteristics of the pathological evolution of atherosclerosis, the roles and pharmacological and clinical studies of PPARs were summarized systematically and updated under different pathological stages and in different vascular cells of atherosclerosis. Moreover, selective PPAR modulators and PPAR-pan agonists can exert their synergistic effects meanwhile reducing the side effects, thereby providing novel insight into future drug development for precise spatial-temporal therapeutic strategy of anti-atherosclerosis targeting PPARs. KEY SCIENTIFIC: Concepts of Review: Based on the spatial and temporal characteristics of atherosclerosis, we have proposed the importance of stage- and cell type-dependent precision therapy. Initially, PPARs improve endothelial cells' dysfunction by inhibiting inflammation and oxidative stress and then regulate macrophages' lipid metabolism and polarization to improve fatty streak. Finally, PPARs reduce fibrous cap formation by suppressing the proliferation and migration of vascular smooth muscle cells (VSMCs). Therefore, research on the cell type-specific mechanisms of PPARs can provide the foundation for space-time drug treatment. Moreover, pharmacological studies have demonstrated that several drugs or compounds can exert their effects by the activation of PPARs. Selective PPAR modulators (that specifically activate gene subsets of PPARs) can exert tissue and cell-specific effects. Furthermore, the dual- or pan-PPAR agonist could perform a better role in balancing efficacy and side effects. Therefore, research on cells/tissue-specific activation of PPARs and PPAR-pan agonists can provide the basis for precision therapy and drug development of PPARs.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA