Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 353
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Am J Orthod Dentofacial Orthop ; 157(5): 680-689, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32354441

RESUMO

INTRODUCTION: Osteoprotegerin-deficient mice develop severe high-turnover osteoporosis with porous low-density trabecular bone from an age-related increase in osteoclast activity and are useful alveolar bone models of osteoporosis or frail periodontal tissue. Bisphosphonate (BP), a first-line drug for osteoporosis, is bone-avid, causing side effects such as brittle and fragile bones and jaw osteonecrosis after tooth extraction. In orthodontics, active movement is precisely controlled by temporarily suppressing and resuming movement. BP impedes such control because of its long half-life of several years in bone. Therefore, we investigated the novel osteoclast-specific inhibitor reveromycin A (RMA), which has a short half-life in bone. We hypothesized that tooth movement could be precisely controlled through temporary discontinuation and re-administration of RMA. METHODS: Osteoprotegerin-deficient mice and wild-type mice were developed as tooth movement models under constant orthodontic force. A constant orthodontic force of 10 g was induced using a nickel-titanium closed coil spring to move the maxillary first molar for 14 days. We administered BP (1.25 mg/kg) or RMA (1.0 mg/kg) continuously and then discontinued it to reveal how the subsequent movement of teeth and surrounding alveolar bone was affected. RESULTS: Continuous BP or RMA administration suppressed osteoclast activity and preserved alveolar bone around the roots, apparently normalizing bone metabolism. Tooth movement remained suppressed after BP discontinuation but resumed at a higher rate after discontinuation of RMA. CONCLUSIONS: RMA appears useful for controlling orthodontic tooth movement because it can be suppressed and resumed through administration and discontinuation, respectively.

2.
J Antibiot (Tokyo) ; 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-32139880

RESUMO

We found that the protein synthesis inhibitor hygromycin B induced the production of secondary metabolites, including lucilactaene, NG-391, fusarubin, 1233A, and 1233B, in the filamentous fungus, Fusarium sp. RK97-94. We identified the biosynthetic gene cluster for 1233A, an HMG-CoA synthase inhibitor. The biosynthetic gene cluster consisted of four genes, one of which was involved in conferring self-resistance to 1233A.

3.
Biosci Biotechnol Biochem ; 84(6): 1303-1307, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32043422

RESUMO

We identified the biosynthetic gene cluster for lucilactaene, a cell cycle inhibitor from a filamentous fungus Fusarium sp. RK 97-94. The luc1 knockout strain accumulated demethylated analogs, indicating the involvement of Luc1 methyltransferase in lucilactaene biosynthesis. Lucilactaene showed potent antimalarial activity. Our data suggested that methylation and ether ring formation are essential for its potent antimalarial activity.

4.
Biosci Biotechnol Biochem ; 84(5): 876-886, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31942814

RESUMO

Enokipodins are antimicrobial sesquiterpenes produced by Flammulina velutipes in a mycelial culture medium. To date, enokipodin production has not been reported in other members of the genus Flammulina. Hence, in this study, the production of enokipodins A, B, C, and D by F. velutipes and F. rossica was investigated. Some strains of F. rossica were confirmed to produce at least one of the four enokipodins in the culture medium. However, some strains of F. velutipes did not produce any of the enokipodins. In an antibacterial assay using liquid medium, enokipodin B showed the strongest growth inhibitory activity against Bacillus subtilis among the four types of enokipodins. Enokipodin B inhibited the spore germination of some plant pathogenic fungi. Enokipodins B and D exerted moderate anti-proliferative activity against some cancer cell lines, and enokipodins A and C inhibited the proliferation of the malarial parasite, Plasmodium falciparum.

5.
Cell Chem Biol ; 27(2): 186-196.e4, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-31813846

RESUMO

The cellular thermal shift assay (CETSA) has recently been devised as a label-free method for target validation of small compounds and monitoring the thermal stabilization or destabilization of proteins due to binding with the compound. Herein, we developed a modified method by combining the CETSA and proteomics analysis based on 2D gel electrophoresis, namely 2DE-CETSA, to identify the thermal stability-shifted proteins by binding with a new compound. We applied the 2DE-CETSA for analysis of a target-unknown compound, NPD10084, which exerts anti-proliferative activity against colorectal cancer cells in vitro and in vivo, and identified pyruvate kinase muscle isoform 2 (PKM2) as a candidate target protein. Interestingly, NPD10084 interrupted protein-protein interactions between PKM2 and ß-catenin or STAT3, with subsequent suppression of downstream signaling. We thus demonstrate that our 2DE-CETSA method is applicable for identification of target compounds discovered by phenotypic screening.

6.
J Microbiol Biotechnol ; 30(1): 31-37, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31752054

RESUMO

We previously identified a new heparinase inhibitor fungal metabolite, named CRM646-A, which showed inhibition of heparinase and telomerase activities in an in vitro enzyme assay and antimetastatic activity in a cell-based assay. In this study, we elucidated the mechanism by which CRM646-A rapidly induced nucleus condensation, plasma membrane disruption and morphological changes by increasing intracellular Ca2+ levels. Furthermore, PD98059, a mitogen-activated protein kinase (MEK) inhibitor, inhibited CRM646-A-induced nucleus condensation through ERK1/2 activation in rat 3Y1 fibroblast cells. We identified CRM646-A as a Ca2+ ionophore-like agent with a distinctly different chemical structure from that of previously reported Ca2+ ionophores. These results indicate that CRM646-A has the potential to be used as a new and effective antimetastatic drug.

7.
Sci Rep ; 9(1): 18023, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31792277

RESUMO

Information about substrate and product selectivity is critical for understanding the function of cytochrome P450 monooxygenases. In addition, comprehensive understanding of changes in substrate selectivity of P450 upon amino acid mutation would enable the design and creation of engineered P450s with desired selectivities. Therefore, systematic methods for obtaining such information are required. Herein, we developed an integrated P450 substrate screening system for the selection of "exemplary" substrates for a P450 of interest. The established screening system accurately selected the known exemplary substrates and also identified previously unknown exemplary substrates for microbial-derived P450s from a library containing sp3-rich synthetic small molecules. Synthetically potent transformations were also found by analyzing the reactions and oxidation products. The screening system was applied to analyze the substrate selectivity of the P450 BM3 mutants F87A and F87A/A330W, which acquired an ability to hydroxylate non-natural substrate steroids regio- and stereoselectively by two amino acid mutations. The distinct transition of exemplary substrates due to each single amino acid mutation was revealed, demonstrating the utility of the established system.

8.
J Antibiot (Tokyo) ; 72(12): 853-854, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31772387
9.
J Antibiot (Tokyo) ; 72(12): 986-990, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31601980

RESUMO

A new antifungal compound YO-001A was found from the culture broth of Streptomyces sp. YO15-A001, which was isolated from a soil sample collected in Toyama Prefecture. YO-001A was identified through morphological changes-based screening of the rice blast fungus, Pyricularia oryzae (P. oryzae). YO-001A is a new 26-membered macrolide of the oligomycin family, which exhibits potent antifungal activity against P. oryzae with an IC50 of 0.012 µM by disrupting mitochondrial respiration via inhibition of the FOF1-ATPase activity.

10.
J Microbiol Methods ; 167: 105743, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31629019

RESUMO

This study compared the chronological life span and survival of Saccharomyces cerevisiae aged in a microplate or bottle, under different aeration and calorie restriction conditions. Our data shows that limited aeration in the microplate-aged culture contributed to slower outgrowth but extended yeast CLS compared to the bottle-aged culture.

11.
J Antibiot (Tokyo) ; 72(12): 855-864, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31554959

RESUMO

Nucleoside antibiotics possess various biological activities such as antibacterial, antifungal, anticancer, and herbicidal activities. RIKEN scientists contributed to this area of research with two representative antifungal nucleoside antibiotics, blasticidin S and polyoxin. Blasticidin S was the first antibiotic exploited in agriculture worldwide. Meanwhile, the polyoxins discovered by Isono and Suzuki are still used globally as an agricultural antibiotic. In this review article, the research on nucleoside antibiotics mainly done by Isono and his collaborators is summarized from the discovery of polyoxin to subsequent investigations.

12.
J Antibiot (Tokyo) ; 72(12): 996-1000, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31481762

RESUMO

Metarhizin C, a stereoisomer of BR-050 was isolated from a fungus Tolypocladium album RK17-F0007 through a screening program to search for new antitumor compounds. A structure of the isomer was determined by spectroscopic methods including detailed analysis of NOESY correlation and mass spectrometry, and found to be identical to that of 3-desacylmetarhizin A with the absolute structure. Previously, it had been isolated by Kikuchi et al and proposed as BR-050 including the stereo-structure. However, detailed analysis for the newly isolated isomer confirmed that 3-desacylmetarhizin A was not identical to BR-050. Therefore, we assigned it metarhizin C as a new BR-050 isomer. Metarhizin C showed selective cytotoxicity against osteosarcoma MG-63 cells in a glucose independent condition with IC50 value of 0.79 µg/ml, while > 30 µg/ml of IC50 value in a normal condition, and inhibited a mitochondrial respiration.

13.
ACS Chem Biol ; 14(9): 1964-1971, 2019 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-31497942

RESUMO

The plant hormone abscisic acid (ABA) regulates the development of various plant organs including seeds, roots, and fruits, and significantly contributes to abiotic stress responses, especially to drought. Since recent climate changes are adversely affecting crop cultivation, enhancement of plant stress tolerance by regulation of ABA signaling would be an important strategy. In the plant genome, ABA receptors are encoded by multiple genes constituting three subfamilies; however, functional differences among them remain unclear. To enhance desired effects of ABA, the biological functions of the receptor family warrant clarification. This study aimed to determine the functional differences among ABA receptors in plants. We screened small-molecule ligands binding to specific receptors, using a chemical array. In vitro evaluation of hit compounds using 11 Arabidopsis ABA receptors revealed that (+)-3'-alkyl ABAs served as agonists for different receptors depending on the length of their 3'-alkyl chains. Combinatorial in vitro and physiological effects of these compounds on the stomata, seeds, and seedlings indicated that, along with subfamily III, receptors of subfamily II are important to induce strong drought responses. Among (+)-3'-alkyl ABAs assessed herein, (+)-3'-butyl ABA induced a transcriptional response and stomatal closure but only slightly inhibited seed germination and growth, suggesting that it enhances drought tolerance. In silico docking simulation and site-directed mutagenesis revealed the amino acid residues contributing to the selective agonist activity of the (+)-3'-alkyl ABAs. These results provide novel insights into the structure and biological effects of 3'-derivatives of ABA and a basis for agrochemical development.

14.
J Antibiot (Tokyo) ; 72(12): 991-995, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31395970

RESUMO

A new siderophore glucuronide, nocardamin glucuronide (1), was isolated together with nocardamin (2) by applying the one strain-many compounds (OSMAC) approach to the ascamycin-producing strain, Streptomyces sp. 80H647, and performing multivariate analysis using mass spectral data. Structure elucidation was accomplished by a combination of NMR and MS analyses. The absolute configuration of the glucuronic acid moiety was found to be ß-D-GlcA by hydrolysis using ß-glucuronidase, subsequent derivatization of the hydrolysate, and comparison with standards. The siderophore activity of 1 was evaluated through the chrome azurol S assay and was comparable to that of 2 and deferoxamine (IC50 13.4, 9.5, and 6.3 µM, respectively). Nocardamin glucuronide (1) is the first example of a siderophore glucuronide.

15.
ACS Chem Biol ; 14(8): 1819-1828, 2019 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-31365229

RESUMO

Thioviridamide, prethioviridamide, and JBIR-140, which are ribosomally synthesized and post-translationally modified peptides (RiPPs) possessing five thioamide bonds, induce selective apoptosis in various cancer cells, especially those expressing the adenovirus oncogene E1A. However, the target protein of this unique family of bioactive compounds was previously unknown. To investigate the mechanism of action, we adopted a combined approach of genome-wide shRNA library screening, transcriptome profiling, and biochemical identification of prethioviridamide-binding proteins. An shRNA screen identified 63 genes involved in cell sensitivity to prethioviridamide, which included translation initiation factors, aminoacyl tRNA synthetases, and mitochondrial proteins. Transcriptome profiling and subsequent analysis revealed that prethioviridamide induces the integrated stress response (ISR) through the GCN2-ATF4 pathway, which is likely to cause cell death. Furthermore, we found that prethioviridamide binds and inhibits respiratory chain complex V (F1Fo-ATP synthase) in mitochondria, suggesting that inhibition of complex V leads to activation of the GCN2-ATF4 pathway. These results imply that the members of a unique family of RiPPs with polythioamide structure target mitochondria to induce the ISR.


Assuntos
Antineoplásicos/farmacologia , Oligopeptídeos/farmacologia , Tioamidas/farmacologia , Fator 4 Ativador da Transcrição/metabolismo , Animais , Antineoplásicos/química , Perfilação da Expressão Gênica , Células HeLa , Humanos , Mitocôndrias/metabolismo , Oligopeptídeos/química , Proteínas Quinases/metabolismo , Processamento de Proteína Pós-Traducional , ATPases Translocadoras de Prótons/antagonistas & inibidores , RNA/metabolismo , Ratos , Transdução de Sinais/fisiologia , Tioamidas/química
16.
J Cell Mol Med ; 23(9): 6283-6294, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31257716

RESUMO

Cucurbitacin B (CuB) isolated from Cucumis melo by using a PC12 cell bioassay system exhibited significant nerve growth factor (NGF)-mimic or NGF-enhancing activity in PC12 and primary neuron cells. It was also demonstrated pro-neurogenesis effects in ICR and APP/PS1 mice and improved memory deficit of APP/PS1 mice. Its possible mechanism includes significant induction of the phosphorylation of glucocorticoid receptor (GR), protein kinase C (PKC), phospholipase C (PLC) and inhibition of cofilin. ChemProteoBase profiling, binding assay and cellular thermal shift assay (CETSA) were used to determine the target protein. Results revealed that CuB could affect actin dynamics as an actin inhibitor but did not bind with GR. The protein level of cofilin in PC12 cells after treating 0.3 µM and different temperatures was significantly higher than that of control group. Other neurotrophic signalling pathways, such as TrkA/TrkB, were analysed with specific inhibitors and Western blot. The inhibitors of TrkA, PLC, PKC, Ras, Raf and ERK1/2 significantly decreased the percentage of PC12 cells with neurite outgrowth and shortened the length of neurite outgrowth induced by CuB. CuB significantly induced the phosphorylation of TrkA, ERK and CREB. The phosphorylation of these proteins was obviously decreased by their specific inhibitors. These results suggest that cofilin is a candidate target protein of CuB in PC12 cells and that the GR/PLC/PKC and TrkA/Ras/Raf/ERK signalling pathways play important roles in the neuroprotective effect of CuB.

17.
Oxid Med Cell Longev ; 2019: 5459862, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31198492

RESUMO

A new compound, bis(4-hydroxybenzyl)ether mono-ß-L-galactopyranoside (1), was isolated from the rhizome of Gastrodia elata Blume. Its structure was elucidated using extensive spectroscopic analysis, including 1D and 2D NMR, HR-ESI-TOF-MS, and chemical derivatization. Compound 1 extended the replicative lifespan of K6001 and the chronological lifespan of YOM36 yeast strains. To understand the mechanism of action, oxidative stress assessment, reactive oxygen species (ROS) and malondialdehyde (MDA) levels, catalase (CAT) and total glutathione peroxidase (GPx) activity assays, and replicative lifespan assay of sod1, sod2, uth1, and skn7 yeast mutant strains were performed. Results indicated the significant increase in the survival rate of yeast under oxidative stress after treatment with 1. ROS and MDA levels were reduced significantly. Meanwhile, the activity of CAT and GPx was significantly increased. The lifespan of sod1, sod2, uth1, and skn7 mutants of K6001 was not affected by 1. Furthermore, we investigated the gene expression related to longevity after administrating 1. The significant increase of Sir2 and reduction of Uth1 gene expression in the 1-treated group were observed. These results indicated that antioxidative stress played an important role in the antiaging effect of 1; Sir2 and Uth1 genes were involved in antiaging effects of 1.


Assuntos
Envelhecimento/efeitos dos fármacos , Galactosídeos/química , Galactosídeos/farmacologia , Gastrodia/química , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Extratos Vegetais/farmacologia , Proteínas de Saccharomyces cerevisiae/metabolismo , Antioxidantes/farmacologia , Malondialdeído/metabolismo , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética
18.
Sci Rep ; 9(1): 5802, 2019 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-30967594

RESUMO

The biosynthetic potential of soil-dwelling actinomycetes to produce diverse bioactive molecules that are useful as drug seeds has been achieved in the laboratory by modifying culture conditions. Availability of a small molecule that can induce secondary metabolism in these microbes can greatly facilitate the exploration of bioactive natural products. In this manuscript, through the screening of natural products and chemical modification, we demonstrated that the presence of the ß-carboline compound, BR-1, enhanced reveromycin A production in Streptomyces sp. SN-593. BR-1 induced reveromycins production at the wide range of concentrations without affecting cell growth. Our study indicates that BR-1 might serve as an alternative to activate specialized metabolite biosynthesis without genetic engineering.

19.
Bioconjug Chem ; 30(5): 1395-1404, 2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-30888797

RESUMO

The X-linked inhibitor of apoptosis protein baculovirus IAP repeat (XIAP BIR3) domain is a promising therapeutic target for cancer treatment. For the mirror-image screening campaign to identify drug candidates from an unexplored mirror-image natural product library, a facile synthetic protocol for XIAP BIR3 domain synthesis was established by a native chemical ligation strategy using conserved cysteines present among BIR domains. The native and mirror-image XIAP BIR3 domains with an appropriate functional group for labeling were prepared using the established protocol. Taking advantage of the resulting synthetic proteins, several bioassay systems were developed to characterize inhibitors of the protein-protein interaction between the XIAP BIR3 domain and the second mitochondria-derived activator of caspases.


Assuntos
Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/antagonistas & inibidores , Sequência de Aminoácidos , Bioensaio , Humanos , Ligação Proteica , Conformação Proteica , Domínios Proteicos , Dobramento de Proteína , Homologia de Sequência de Aminoácidos , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/química , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/metabolismo
20.
FEBS Lett ; 593(8): 763-776, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30874300

RESUMO

Differences in the metabolism of cancer cells or cancer stem cells (CSCs) as compared to normal cells have provided avenues to safely target cancers. To discover metabolic inhibitors of CSCs, we performed alkaline phosphatase- and tumoursphere-based drug screening using induced cancer stem cell-like cells. From the screening of a RIKEN NPDepo chemical library, we discovered NPD2381 as a novel and selective cancer-stemness inhibitor that targets mitochondrial metabolism. Using our ChemProteoBase profiling, we found that NPD2381 increases the expression of enzymes within the serine biosynthesis pathway. We also found a role for serine in protecting cancer cells from mitochondrial inhibitors. Our results suggest the existence of a compensatory mechanism to increase the level of intracellular serine in response to mitochondrial inhibitors.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA