Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 83
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
EMBO Rep ; 24(7): e56212, 2023 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-37154297

RESUMO

A previous genome-wide association study (GWAS) revealed an association of the noncoding SNP rs1663689 with susceptibility to lung cancer in the Chinese population. However, the underlying mechanism is unknown. In this study, using allele-specific 4C-seq in heterozygous lung cancer cells combined with epigenetic information from CRISPR/Cas9-edited cell lines, we show that the rs1663689 C/C variant represses the expression of ADGRG6, a gene located on a separate chromosome, through an interchromosomal interaction of the rs1663689 bearing region with the ADGRG6 promoter. This reduces downstream cAMP-PKA signaling and subsequently tumor growth both in vitro and in xenograft models. Using patient-derived organoids, we show that rs1663689 T/T-but not C/C-bearing lung tumors are sensitive to the PKA inhibitor H89, potentially informing therapeutic strategies. Our study identifies a genetic variant-mediated interchromosomal interaction underlying ADGRG6 regulation and suggests that targeting the cAMP-PKA signaling pathway may be beneficial in lung cancer patients bearing the homozygous risk genotype at rs1663689.


Assuntos
Estudo de Associação Genômica Ampla , Neoplasias Pulmonares , Humanos , Neoplasias Pulmonares/genética , Pulmão , Receptores Acoplados a Proteínas G/genética , Regulação da Expressão Gênica
2.
Brief Bioinform ; 23(1)2022 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-34875683

RESUMO

MiRNAs are a class of small non-coding RNA molecules that play an important role in many biological processes, and determining miRNA-disease associations can benefit drug development and clinical diagnosis. Although great efforts have been made to develop miRNA-disease association prediction methods, few attention has been paid to in-depth classification of miRNA-disease associations, e.g. up/down-regulation of miRNAs in diseases. In this paper, we regard known miRNA-disease associations as a signed bipartite network, which has miRNA nodes, disease nodes and two types of edges representing up/down-regulation of miRNAs in diseases, and propose a signed graph neural network method (SGNNMD) for predicting deregulation types of miRNA-disease associations. SGNNMD extracts subgraphs around miRNA-disease pairs from the signed bipartite network and learns structural features of subgraphs via a labeling algorithm and a neural network, and then combines them with biological features (i.e. miRNA-miRNA functional similarity and disease-disease semantic similarity) to build the prediction model. In the computational experiments, SGNNMD achieves highly competitive performance when compared with several baselines, including the signed graph link prediction methods, multi-relation prediction methods and one existing deregulation type prediction method. Moreover, SGNNMD has good inductive capability and can generalize to miRNAs/diseases unseen during the training.


Assuntos
MicroRNAs , Redes Neurais de Computação , Algoritmos , Biologia Computacional/métodos , Regulação para Baixo , MicroRNAs/genética
3.
Brief Bioinform ; 23(1)2022 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-34893793

RESUMO

Drug-drug interactions (DDIs) are one of the major concerns in pharmaceutical research, and a number of computational methods have been developed to predict whether two drugs interact or not. Recently, more attention has been paid to events caused by the DDIs, which is more useful for investigating the mechanism hidden behind the combined drug usage or adverse reactions. However, some rare events may only have few examples, hindering them from being precisely predicted. To address the above issues, we present a few-shot computational method named META-DDIE, which consists of a representation module and a comparing module, to predict DDI events. We collect drug chemical structures and DDIs from DrugBank, and categorize DDI events into hundreds of types using a standard pipeline. META-DDIE uses the structures of drugs as input and learns the interpretable representations of DDIs through the representation module. Then, the model uses the comparing module to predict whether two representations are similar, and finally predicts DDI events with few labeled examples. In the computational experiments, META-DDIE outperforms several baseline methods and especially enhances the predictive capability for rare events. Moreover, META-DDIE helps to identify the key factors that may cause DDI events and reveal the relationship among different events.


Assuntos
Interações Medicamentosas , Preparações Farmacêuticas , Bases de Dados Factuais , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Humanos , Modelos Teóricos
4.
J Periodontal Res ; 59(2): 249-258, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38115631

RESUMO

OBJECTIVE: To assess the effects of amoxicillin and metronidazole with scaling and root planing (SRP) on periodontal parameters and glycemic control in patients with severe periodontitis and diabetes mellitus. BACKGROUND: Adjunctive antibiotics use is advantageous for treating periodontitis in patients with severe periodontitis and diabetes. However, the effects of adjunctive antibiotic use on hemoglobin A1c (HbA1c) levels remain unclear. METHODS: This short-term, randomized controlled trial enrolled patients with severe periodontitis and type 2 diabetes. The patients were randomly allocated to SPR only (i.e., control) or SPR + antibiotics (500 mg of amoxicillin and 200 mg of metronidazole, three times daily for 7 days) groups. Periodontal and hematological parameters were assessed at baseline and 3 months after treatment. Inter- and intra-group analyses were performed using Student's t-tests, Mann-Whitney U tests, and the binary logistic regression models. p-values of <.05 were considered statistically significant. RESULTS: This study enrolled 49 patients, with 23 and 26 patients in the SRP-only and SRP + antibiotics groups, respectively. The periodontal parameters improved significantly and similarly in both groups after treatment (p < .05). The SRP + antibiotics group had more sites of improvement than the SRP-only group when the initial probing depth was >6 mm. (698 [78.96%] vs. 545 [73.35%], p = .008). The HbA1c levels decreased in the SRP-only and SRP + antibiotics groups after treatment (0.39% and 0.53%, respectively). The multivariable binary logistic regression model demonstrated that antibiotics administration and a high baseline HbA1c level were associated with a greater reduction in the HbA1c level (odds ratio = 4.551, 95% confidence interval: 1.012-20.463; odds ratio = 7.162, 95% confidence interval: 1.359-37.753, respectively). CONCLUSIONS: SRP and SRP plus systemic antibiotics were beneficial for glycemic control. Adjunctive antibiotic use slightly improved the outcome for patients with severe periodontitis and poorly controlled diabetes.


Assuntos
Periodontite Crônica , Diabetes Mellitus Tipo 2 , Periodontite , Humanos , Metronidazol/uso terapêutico , Amoxicilina/uso terapêutico , Aplainamento Radicular , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Controle Glicêmico , Hemoglobinas Glicadas , Resultado do Tratamento , Antibacterianos/uso terapêutico , Periodontite/complicações , Periodontite/tratamento farmacológico , Raspagem Dentária , Periodontite Crônica/tratamento farmacológico
5.
Cereb Cortex ; 33(4): 1090-1103, 2023 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-35348645

RESUMO

In the digital age, while short videos present vital events with powerful information, the presence of cultural cues may bias our processing of videos of foreign cultures. However, the underlying neurocognitive processes remain unclear. In this study, we hypothesized that cultural cues might bias video processing by either enhancing cultural perspective-taking or shifting cultural self-schema. To test these hypotheses, we used a novel paradigm in which the cultural cue was a real cultural other (the priming participants) who watched American/Chinese videos together with the primed participants. The results showed that when the cue was present, the right temporoparietal junction (rTPJ) response to videos with other cultural content was shifted, showing a priming effect. Moreover, the activity pattern in the rTPJ was more congruent with the primed culture than with the original culture, reflecting a neural biasing effect. Finally, intersubject representational similarity analysis indicated that the neural biasing effect in the rTPJ was more closely associated with cultural perspective-taking than with cultural self-schema. In summary, these findings support the perspective-taking hypothesis, suggesting that cultural cues can significantly bias our cultural mindset by altering cultural perspective-taking when we are exposed to culture-relevant naturalistic stimuli.


Assuntos
Lobo Parietal , Lobo Temporal , Humanos , Lobo Parietal/fisiologia , Lobo Temporal/fisiologia , Sinais (Psicologia)
6.
J Pharmacol Sci ; 152(3): 167-177, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37257944

RESUMO

Cisplatin, a platinum-based anticancer drug used frequently in cancer treatment, causes skeletal muscle atrophy. It was predicted that the proteolytic pathway is enhanced as the mechanism of this atrophy. Therefore, we investigated whether a platinum-based anticancer drug affects the expression of the major proteins of skeletal muscle, myosin heavy chain (MyHC). Mice were injected with cisplatin or oxaliplatin for four consecutive days. C2C12 myotubes were treated using cisplatin and oxaliplatin. Administration of platinum-based anticancer drug reduced quadriceps mass and muscle strength compared to the control group. Protein levels of all MyHC isoforms were reduced in the platinum-based anticancer drug groups. However, only Myh2 (MyHC-IIa) gene expression in skeletal muscle of mice treated with platinum-based anticancer drugs was found to be reduced. Treatment of C2C12 myotubes with platinum-based anticancer drugs reduced the protein levels of all MyHCs, and treatment with the proteasome inhibitor MG-132 restored this reduction. The expression of Mef2c, which was predicted to act upstream of Myh2, was reduced in the skeletal muscle of mice treated systemically with platinum-based anticancer drug. Degradation of skeletal muscle MyHCs by proteasomes may be a factor that plays an important role in muscle mass loss in platinum-based anticancer drug-induced muscle atrophy.


Assuntos
Antineoplásicos , Cadeias Pesadas de Miosina , Camundongos , Animais , Cadeias Pesadas de Miosina/genética , Cadeias Pesadas de Miosina/metabolismo , Regulação para Baixo , Cisplatino , Platina/metabolismo , Oxaliplatina , Músculo Esquelético/metabolismo , Fibras Musculares Esqueléticas/metabolismo , Antineoplásicos/farmacologia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Atrofia/metabolismo
7.
J Med Genet ; 59(9): 840-849, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34544842

RESUMO

BACKGROUND: A large number of new causative and risk genes for amyotrophic lateral sclerosis (ALS) have been identified mostly in patients of European ancestry. In contrast, we know relatively little regarding the genetics of ALS in other ethnic populations. This study aims to provide a comprehensive analysis of the genetics of ALS in an unprecedented large cohort of Chinese mainland population and correlate with the clinical features of rare variants carriers. METHODS: A total of 1587 patients, including 64 familial ALS (FALS) and 1523 sporadic ALS (SALS), and 1866 in-house controls were analysed by whole-exome sequencing and/or testing for G4C2 repeats in C9orf72. Forty-one ALS-associated genes were analysed. FINDINGS: 155 patients, including 26 (40.6%) FALS and 129 (8.5%) SALS, carrying rare pathogenic/likely pathogenic (P/LP) variants of ALS causative genes were identified. SOD1 was the most common mutated gene, followed by C9orf72, FUS, NEK1, TARDBP and TBK1. By burden analysis, rare variants in SOD1, FUS and TARDBP contributed to the collective risk for ALS (p<2.5e-6) at the gene level, but at the allelic level TARDBP p.Gly294Val and FUS p.Arg521Cys and p.Arg521His were the most important single variants causing ALS. Clinically, P/LP variants in TARDBP and C9orf72 were associated with poor prognosis, in FUS linked with younger age of onset, and C9orf72 repeats tended to affect cognition. CONCLUSIONS: Our data provide essential information for understanding the genetic and clinical features of ALS in China and for optimal design of genetic testing and evaluation of disease prognosis.


Assuntos
Esclerose Lateral Amiotrófica , Esclerose Lateral Amiotrófica/epidemiologia , Esclerose Lateral Amiotrófica/genética , Proteína C9orf72/genética , Estudos de Coortes , Predisposição Genética para Doença , Humanos , Mutação/genética , Superóxido Dismutase-1/genética
8.
Sensors (Basel) ; 23(22)2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-38005603

RESUMO

Sintering is a commonly used agglomeration process to prepare iron ore fines for blast furnace. The quality of sinter significantly impacts the blast furnace ironmaking process. In the vast majority of sintering plants, the judgment of sintering quality still relies on the intuitive observation of the cross section at sintering machine tail by operators, which is susceptible to the external environment and the experience of operators. In this paper, we propose a new sintering state recognition method using deep learning based feature selection and ensemble learning. First, features from the infrared thermal images of sinter cross section at the tail of the sinterer are extracted based on ResNeXt. Then, to eliminate the irrelevant, redundant and noisy features, an efficient feature selection method based on binary state transition algorithm (BSTA) is proposed to find the truly useful features. Subsequently, an ensemble learning (EL) method based on group decision making (GDM) is proposed to recognize the sintering states. Novel combination strategies considering the varying performance of the base learners are designed to further improve recognition accuracy. Industrial experiments conducted at a steel plant verify the effectiveness and superiority of the proposed method.

9.
FASEB J ; 35(8): e21723, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34224609

RESUMO

Sperm acquire the ability to fertilize in a process called capacitation and undergo hyperactivation, a change in the motility pattern, which depends on Ca2+ transport by CatSper channels. CatSper is essential for fertilization and it is subjected to a complex regulation that is not fully understood. Here, we report that similar to CatSper, Cdc42 distribution in the principal piece is confined to four linear domains and this localization is disrupted in CatSper1-null sperm. Cdc42 inhibition impaired CatSper activity and other Ca2+ -dependent downstream events resulting in a severe compromise of the sperm fertilizing potential. We also demonstrate that Cdc42 is essential for CatSper function by modulating cAMP production by soluble adenylate cyclase (sAC), providing a new regulatory mechanism for the stimulation of CatSper by the cAMP-dependent pathway. These results reveal a broad mechanistic insight into the regulation of Ca2+ in mammalian sperm, a matter of critical importance in male infertility as well as in contraception.


Assuntos
Canais de Cálcio/metabolismo , Espermatozoides/metabolismo , Proteína cdc42 de Ligação ao GTP/metabolismo , Animais , Cálcio/metabolismo , Canais de Cálcio/deficiência , Canais de Cálcio/genética , Sinalização do Cálcio , AMP Cíclico/metabolismo , Feminino , Fertilização in vitro , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Biológicos , Transdução de Sinais , Capacitação Espermática/fisiologia , Motilidade dos Espermatozoides/fisiologia , Cauda do Espermatozoide/metabolismo , Espermatozoides/efeitos dos fármacos , Espermatozoides/ultraestrutura , Proteína cdc42 de Ligação ao GTP/antagonistas & inibidores
10.
Food Microbiol ; 108: 104092, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36088123

RESUMO

Escherichia coli shows the potential of indicating foodborne pathogens. The purpose of this study is to investigate the association between E. coli and foodborne pathogens such as Campylobacter, Salmonella, and Listeria in pastured poultry farms, as well as in related processing facilities. Five different sample types: (i) feces, (ii) soil, (iii) whole carcass rinse during processing (WCR-P), (iv) whole carcass rinse of final product after chilling and storage (WCR-F), and (v) ceca were measured for E. coli populations. A logistic regression model for pathogen presence was developed for each sample type. The E. coli population significantly increased the predicted probability of Salmonella presence for soil and WCR-P samples (p = 0.0011 and p = 0.0157 respectively). For Campylobacter, the initial prevalence in feces and ceca were high and a decreasing trend of detecting Campylobacter was observed as E. coli concentration increased. In soil and WCR-P models, the probability of the presence of Campylobacter significantly increased as E. coli population increased. These models provide a practical and effective way of evaluating the relationship between E. coli and foodborne pathogens and enable prediction of foodborne pathogen presence based on E. coli prevalence within the pastured poultry farm-to-fork continuum.


Assuntos
Campylobacter , Aves Domésticas , Animais , Galinhas , Escherichia coli , Fazendas , Salmonella , Solo
11.
J Mol Evol ; 89(4-5): 287-301, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33755734

RESUMO

Auxin response factors (ARFs) influence plant growth and development via the coupling of basic biological processes. However, the evolution, expansion, and regulatory mechanisms of ARFs in the domesticated crop quinoa after artificial selection remain elusive. In this study, we systematically identified 30 Chenopodium quinoa ARFs (CqARFs). In this typical domesticated crop, ARFs divided into three subfamilies are subjected to strong purification selection and have a highly conserved evolutionary pattern. Polyploidy is the primary reason for the expansion of the ARF family after quinoa domestication. The expression patterns of CqARFs in different tissues have been differentiated, and CqARF2, 5, 9 and 10 from class A have the characteristics of local heterogeneous expression in different regions of roots, which may be the key factors for crops to respond in complex environments. Overall, we examined the evolution and expansion of ARFs in representative domesticated crops using the genome, transcriptome, and molecular biology and discovered a class A ARF-centered heterogeneous expression network that played an important role in auxin signaling and environmental responses. We provide new insights into how ARFs promote domesticated crop adaptation to artificial selection by polyploid expansion.


Assuntos
Chenopodium quinoa , Chenopodium quinoa/genética , Domesticação , Evolução Molecular , Regulação da Expressão Gênica de Plantas/genética , Ácidos Indolacéticos , Filogenia
12.
Bioinformatics ; 36(15): 4316-4322, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32407508

RESUMO

MOTIVATION: Drug-drug interactions (DDIs) are one of the major concerns in pharmaceutical research. Many machine learning based methods have been proposed for the DDI prediction, but most of them predict whether two drugs interact or not. The studies revealed that DDIs could cause different subsequent events, and predicting DDI-associated events is more useful for investigating the mechanism hidden behind the combined drug usage or adverse reactions. RESULTS: In this article, we collect DDIs from DrugBank database, and extract 65 categories of DDI events by dependency analysis and events trimming. We propose a multimodal deep learning framework named DDIMDL that combines diverse drug features with deep learning to build a model for predicting DDI-associated events. DDIMDL first constructs deep neural network (DNN)-based sub-models, respectively, using four types of drug features: chemical substructures, targets, enzymes and pathways, and then adopts a joint DNN framework to combine the sub-models to learn cross-modality representations of drug-drug pairs and predict DDI events. In computational experiments, DDIMDL produces high-accuracy performances and has high efficiency. Moreover, DDIMDL outperforms state-of-the-art DDI event prediction methods and baseline methods. Among all the features of drugs, the chemical substructures seem to be the most informative. With the combination of substructures, targets and enzymes, DDIMDL achieves an accuracy of 0.8852 and an area under the precision-recall curve of 0.9208. AVAILABILITY AND IMPLEMENTATION: The source code and data are available at https://github.com/YifanDengWHU/DDIMDL. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Aprendizado Profundo , Preparações Farmacêuticas , Interações Medicamentosas , Redes Neurais de Computação , Software
13.
BMC Neurol ; 21(1): 28, 2021 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-33468086

RESUMO

BACKGROUND: Abnormal eye movements are common in spinocerebellar ataxias Type 3 (SCA3). We conducted the research to explore the frequency of abnormal eye movements in Chinese patients with SCA3, to compare the demographic and clinical characteristics between SCA3 patients with and without each type of abnormal eye movement, and to explore the correlation between abnormal eye movements and the severity of ataxia. METHODS: Seventy-four patients with SCA3 were enrolled in this cross-sectional study. Six types of abnormal eye movements including impaired smooth pursuit, increased square-wave jerks (SWJ), gaze-evoked nystagmus (GEN), slowing of saccades, saccadic hypo/hypermetria and supranuclear gaze palsy were evaluated by experienced neurologists. The severity of ataxia was evaluated by Scale for the Assessment and Rating of Ataxia (SARA). RESULTS: The prevalence of impaired smooth pursuit, increased SWJ, GEN, slowing of saccades, saccadic hypo/hypermetria and supranuclear gaze palsy in Chinese SCA3 patients was 28.4, 13.5, 78.4, 41.9, 23.0, and 5.4%, respectively. SCA3 patients with GEN had higher scores of International Cooperative Ataxia Rating Scale (ICARS-IV) and total ICARS, and longer length of CAG repeat than patients without GEN. SCA3 patients with slowing of saccades had a longer disease duration, higher scores of ICARS-I, ICARS-II, total ICARS and SARA than patients without slowing of saccades. SCA3 patients with saccadic hypo/hypermetria had higher scores of ICARS-III, ICARS-IV, and SARA than patients without saccadic hypo/hypermetria. The demographic and clinical characteristics did not differ significantly between SCA3 patients with and without impaired smooth pursuit, increased SWJ, or supranuclear gaze palsy. Multivariate linear regression showed that the number of abnormal eye movements (0-6), disease duration, Hamilton Depression Rating Scale-24 (HDRS-24) score, and CAG repeat length were positively correlated with SARA score, whereas Montreal Cognitive Assessment (MoCA) score was negatively correlated with SARA score in SCA3. CONCLUSIONS: An increased number of abnormal eye movement types correlated with the severity of ataxia in SCA3.


Assuntos
Doença de Machado-Joseph/complicações , Transtornos da Motilidade Ocular/epidemiologia , Transtornos da Motilidade Ocular/etiologia , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência
14.
Chem Biodivers ; 18(2): e2000856, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33295037

RESUMO

Dioscorea polystachya, named Chinese yam, is widely cultivated as a functional food and natural medicine in China. There is currently little information about the chemical characteristics of Dioscorea polystachya in different organs (tuber cortex and tuber flesh) and at various ages. In this study, an ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) was used to profile chemical compounds in Dioscorea polystachya. As a result, thirty-eight compounds were detected in yam tuber cortex and tuber flesh. More compounds were detected in yam tuber cortex than in tuber flesh. Compounds such as dehydroepiandrosterone, allantoin and flavonoids were selected as biomarker candidates. Dehydroepiandrosterone was found more abundant in tuber flesh, while allantoin and flavonoids showed higher levels in tuber cortex. Furthermore, the levels of dioscin, malvalic acid and sucrose differed significantly among age groups and were highest in the tubers at 2 years. While the levels of allantoin, adenosine and glutamine increased with the growing years and were highest at 4 years. Thus, 2-year old Dioscorea polystachya tubers could be harvested to prepare dioscin, malvalic acid and sucrose supplements. The 4-year-old Dioscorea polystachya tubers would be the best choice for obtaining a large amount of allantoin and adenosine in industrial production.


Assuntos
Dioscorea/química , Tubérculos/química , Alantoína/análise , Cromatografia Líquida de Alta Pressão/métodos , Desidroepiandrosterona/análise , Dioscorea/crescimento & desenvolvimento , Flavonoides/análise , Espectrometria de Massas/métodos , Tubérculos/crescimento & desenvolvimento
15.
J Cell Sci ; 131(11)2018 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-29739876

RESUMO

Conception in mammals is determined by the fusion of a sperm cell with an oocyte during fertilization. Motility is one of the features of sperm that allows them to succeed in fertilization, and their flagellum is essential for this function. Longitudinally, the flagellum can be divided into the midpiece, the principal piece and the end piece. A precise cytoskeletal architecture of the sperm tail is key for the acquisition of fertilization competence. It has been proposed that the actin cytoskeleton plays essential roles in the regulation of sperm motility; however, the actin organization in sperm remains elusive. In the present work, we show that there are different types of actin structures in the sperm tail by using three-dimensional stochastic optical reconstruction microscopy (STORM). In the principal piece, actin is radially distributed between the axoneme and the plasma membrane. The actin-associated proteins spectrin and adducin are also found in these structures. Strikingly, polymerized actin in the midpiece forms a double-helix that accompanies mitochondria. Our findings illustrate a novel specialized structure of actin filaments in a mammalian cell.


Assuntos
Citoesqueleto de Actina/química , Cauda do Espermatozoide/metabolismo , Citoesqueleto de Actina/genética , Citoesqueleto de Actina/metabolismo , Actinas/química , Actinas/genética , Actinas/metabolismo , Animais , Masculino , Camundongos , Conformação Proteica em alfa-Hélice , Cauda do Espermatozoide/química
16.
J Cell Sci ; 131(21)2018 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-30301778

RESUMO

Filamentous actin (F-actin) is a key factor in exocytosis in many cell types. In mammalian sperm, acrosomal exocytosis (denoted the acrosome reaction or AR), a special type of controlled secretion, is regulated by multiple signaling pathways and the actin cytoskeleton. However, the dynamic changes of the actin cytoskeleton in live sperm are largely not understood. Here, we used the powerful properties of SiR-actin to examine actin dynamics in live mouse sperm at the onset of the AR. By using a combination of super-resolution microscopy techniques to image sperm loaded with SiR-actin or sperm from transgenic mice containing Lifeact-EGFP, six regions containing F-actin within the sperm head were revealed. The proportion of sperm possessing these structures changed upon capacitation. By performing live-cell imaging experiments, we report that dynamic changes of F-actin during the AR occur in specific regions of the sperm head. While certain F-actin regions undergo depolymerization prior to the initiation of the AR, others remain unaltered or are lost after exocytosis occurs. Our work emphasizes the utility of live-cell nanoscopy, which will undoubtedly impact the search for mechanisms that underlie basic sperm functions.This article has an associated First Person interview with the first author of the paper.


Assuntos
Acrossomo/metabolismo , Citoesqueleto de Actina/metabolismo , Espermatozoides/metabolismo , Animais , Exocitose , Masculino , Camundongos , Imagem Molecular
17.
Phys Rev Lett ; 125(5): 058101, 2020 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-32794890

RESUMO

Diffusion of tracer particles in the cytoplasm of mammalian cells is often anomalous with a marked heterogeneity even within individual particle trajectories. Despite considerable efforts, the mechanisms behind these observations have remained largely elusive. To tackle this problem, we performed extensive single-particle tracking experiments on quantum dots in the cytoplasm of living mammalian cells at varying conditions. Analyses of the trajectories reveal a strong, microtubule-dependent subdiffusion with antipersistent increments and a substantial heterogeneity. Furthermore, particles stochastically switch between different mobility states, most likely due to transient associations with the cytoskeleton-shaken endoplasmic reticulum network. Comparison to simulations highlight that all experimental observations can be fully described by an intermittent fractional Brownian motion, alternating between two states of different mobility.


Assuntos
Citoplasma/metabolismo , Modelos Biológicos , Citoesqueleto de Actina/metabolismo , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Simulação por Computador , Citocalasina D/farmacologia , Citoplasma/efeitos dos fármacos , Citoesqueleto/efeitos dos fármacos , Citoesqueleto/metabolismo , Difusão , Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Células HeLa , Humanos , Microtúbulos/efeitos dos fármacos , Microtúbulos/metabolismo , Nocodazol/farmacologia , Pontos Quânticos , Processos Estocásticos , Tiazolidinas/farmacologia
18.
Artigo em Inglês | MEDLINE | ID: mdl-32939872

RESUMO

AIM: Recently, microRNA-149 (miR-149) has been indicated to act as an oncogene or a tumor suppressor in various malignant tumors, while its inner mechanisms in recurrent miscarriage (RM) are still in infancy. Therein, this study intends to decode the mechanism of miR-149 in RM. METHODS: miR-149 and RUNX2 expression in the chorionic tissues of normal pregnant women and RM patients were first examined, and the correlation between miR-149 and RUNX2 was analyzed. Subsequently, miR-149 was upregulated in HTR-8 cells or downregulated in BEWO cells, and then the changes in biological functions of trophoblasts in RM were detected. Furthermore, the expression of PTEN/Akt signaling pathway-related factors in trophoblasts was detected by western blot analysis. RESULTS: miR-149 expression was increased while RUNX2 expression was suppressed in RM patients, and miR-149 was negatively correlated with RUNX2. Overexpressed miR-149 induced cell apoptosis and inhibited cell activity, while reduced miR-149 in trophoblasts contributed to opposite experimental results. Moreover, miR-149 promoted the expression of PTEN and inhibited Akt phosphorylation by targeting RUNX2, thereby inhibiting trophoblast activity and promoting their apoptosis. CONCLUSION: Our study demonstrates that miR-149 knockdown halted the RM development through upregulating RUNX2 and activation of the PTEN/Akt signaling pathway.

19.
J Biol Chem ; 293(24): 9435-9447, 2018 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-29700114

RESUMO

Protein kinase A (PKA) is a broad-spectrum Ser/Thr kinase involved in the regulation of several cellular activities. Thus, its precise activation relies on being localized at specific subcellular places known as discrete PKA signalosomes. A-Kinase anchoring proteins (AKAPs) form scaffolding assemblies that play a pivotal role in PKA regulation by restricting its activity to specific microdomains. Because one of the first signaling events observed during mammalian sperm capacitation is PKA activation, understanding how PKA activity is restricted in space and time is crucial to decipher the critical steps of sperm capacitation. Here, we demonstrate that the anchoring of PKA to AKAP is not only necessary but also actively regulated during sperm capacitation. However, we find that once capacitated, the release of PKA from AKAP promotes a sudden Ca2+ influx through the sperm-specific Ca2+ channel CatSper, starting a tail-to-head Ca2+ propagation that triggers the acrosome reaction. Three-dimensional super-resolution imaging confirmed a redistribution of PKA within the flagellar structure throughout the capacitation process, which depends on anchoring to AKAP. These results represent a new signaling event that involves CatSper Ca2+ channels in the acrosome reaction, sensitive to PKA stimulation upon release from AKAP.


Assuntos
Proteínas de Ancoragem à Quinase A/metabolismo , Reação Acrossômica , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Mapas de Interação de Proteínas , Capacitação Espermática , Espermatozoides/citologia , Animais , Proteínas Quinases Dependentes de AMP Cíclico/análise , Exocitose , Fertilização , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais , Espermatozoides/metabolismo
20.
Cancer ; 125(21): 3836-3844, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31402456

RESUMO

BACKGROUND: The authors hypothesized that epigenetic changes may help to clarify the underlying biologic mechanism linking aspirin use to breast cancer prognosis. To the authors' knowledge, this is the first epidemiologic study to examine whether global methylation and/or tumor promoter methylation of breast cancer-related genes interact with aspirin use to impact mortality after breast cancer. METHODS: Prediagnosis aspirin use was assessed through in-person interviews within a population-based cohort of 1508 women diagnosed with a first primary breast cancer in 1996 and 1997. Global methylation in peripheral blood was assessed by long interspersed elements-1 (LINE-1) and the luminometric methylation assay. Promoter methylation of 13 breast cancer-related genes was measured in tumor by methylation-specific polymerase chain reaction and the MethyLight assay. Vital status was determined by the National Death Index through December 31, 2014 (N = 202/476 breast cancer-specific/all-cause deaths identified among 1266 women with any methylation assessment and complete aspirin data). Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% CIs, and the likelihood ratio test was used to evaluate multiplicative interactions. RESULTS: All-cause mortality was elevated among aspirin users who had methylated promotor of BRCA1 (HR, 1.67; 95% CI, 1.26-2.22), but not among those with unmethylated promoter of BRCA1 (HR, 0.99; 95% CI, 0.67-1.45; P for interaction ≤.05). Decreased breast cancer-specific mortality was observed among aspirin users who had unmethylated promotor of BRCA1 and PR and global hypermethylation of LINE-1 (HR, 0.60, 0.78, and 0.63, respectively; P for interaction ≤.05), although the 95% CIs included the null. CONCLUSIONS: The current study suggests that the LINE-1 global methylation and promoter methylation of BRCA1 and PR in tumor may interact with aspirin use to influence mortality after breast cancer.


Assuntos
Aspirina/administração & dosagem , Neoplasias da Mama/genética , Metilação de DNA , Epigênese Genética , Regiões Promotoras Genéticas/genética , Adulto , Idoso , Anti-Inflamatórios não Esteroides/administração & dosagem , Proteína BRCA1/genética , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/mortalidade , Causas de Morte/tendências , Estudos de Coortes , Feminino , Predisposição Genética para Doença/genética , Humanos , Pessoa de Meia-Idade , Vigilância da População/métodos , Prognóstico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA