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1.
Animals (Basel) ; 13(16)2023 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-37627413

RESUMO

The analysis of AR is widely used to detect loss of acrosome in sperm, but the subjective decisions of experts affect the accuracy of the examination. Therefore, we develop an ARCS for objectivity and consistency of analysis using convolutional neural networks (CNNs) trained with various magnification images. Our models were trained on 215 microscopic images at 400× and 438 images at 1000× magnification using the ResNet 50 and Inception-ResNet v2 architectures. These models distinctly recognized micro-changes in the PM of AR sperms. Moreover, the Inception-ResNet v2-based ARCS achieved a mean average precision of over 97%. Our system's calculation of the AR ratio on the test dataset produced results similar to the work of the three experts and could do so more quickly. Our model streamlines sperm detection and AR status determination using a CNN-based approach, replacing laborious tasks and expert assessments. The ARCS offers consistent AR sperm detection, reduced human error, and decreased working time. In conclusion, our study suggests the feasibility and benefits of using a sperm diagnosis artificial intelligence assistance system in routine practice scenarios.

2.
Reprod Domest Anim ; 55(5): 624-631, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32108385

RESUMO

This study investigated the relationship between acrosome reactions and fatty acid composition with respect to fertility in boar sperm. The acrosome reaction was induced more than 85% by 60 mM methyl-beta-cyclodextrin (MBCD), and plasma membrane integrity was significantly reduced dependent on the MBCD level in boar sperm (p < .05). The acrosome-reacted sperm exhibited significantly higher saturated fatty acids (SFAs) and lower polyunsaturated fatty acids (PUFAs) composition compared to the non-acrosome reaction group (p < .0001). In addition, the PUFAs, C22:5n-6 (docosapentaenoic acid [DPA]; p < .01) and C22:6n-3 (docosahexaenoic acid [DHA]; p < .0001) were significantly decreased, and cleavage and blastocyst formation of oocytes were significantly (p < .0001) decreased in acrosome-reacted sperm relative to non-acrosome-reacted sperm. Moreover, acrosome reaction was positively correlated with SFAs, whereas negatively correlated with PUFAs, of the PUFAs, the DPA (p = .0005) and DHA (p = <.0001) were negatively correlated with the acrosome reaction. Therefore, these results suggest that the PUFAs composition of sperm is closely involved in acrosome reaction in pigs.


Assuntos
Reação Acrossômica/efeitos dos fármacos , Ácidos Graxos Insaturados/química , Espermatozoides/fisiologia , beta-Ciclodextrinas/farmacologia , Animais , Membrana Celular/efeitos dos fármacos , Fertilização in vitro/veterinária , Masculino , Oócitos , Espermatozoides/química , Sus scrofa
3.
PLoS One ; 13(8): e0202705, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30153294

RESUMO

Feature selection is considered to be one of the most critical methods for choosing appropriate features from a larger set of items. This task requires two basic steps: ranking and filtering. Of these, the former necessitates the ranking of all features, while the latter involves filtering out all irrelevant features based on some threshold value. In this regard, several feature selection methods with well-documented capabilities and limitations have already been proposed. Similarly, feature ranking is also nontrivial, as it requires the designation of an optimal cutoff value so as to properly select important features from a list of candidate features. However, the availability of a comprehensive feature ranking and a filtering approach, which alleviates the existing limitations and provides an efficient mechanism for achieving optimal results, is a major problem. Keeping in view these facts, we present an efficient and comprehensive univariate ensemble-based feature selection (uEFS) methodology to select informative features from an input dataset. For the uEFS methodology, we first propose a unified features scoring (UFS) algorithm to generate a final ranked list of features following a comprehensive evaluation of a feature set. For defining cutoff points to remove irrelevant features, we subsequently present a threshold value selection (TVS) algorithm to select a subset of features that are deemed important for the classifier construction. The uEFS methodology is evaluated using standard benchmark datasets. The extensive experimental results show that our proposed uEFS methodology provides competitive accuracy and achieved (1) on average around a 7% increase in f-measure, and (2) on average around a 5% increase in predictive accuracy as compared with state-of-the-art methods.


Assuntos
Algoritmos , Benchmarking , Bases de Dados Factuais
4.
Biochem Biophys Res Commun ; 495(2): 1775-1781, 2018 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-29229391

RESUMO

Clusterin is a multifunctional glycoprotein that plays important roles and is up-regulated in liver diseases such as hepatitis and hepatocellular carcinoma. However, little is known about the significance of clusterin in the pathogenesis of non-alcoholic steatohepatitis (NASH). The aim of this study is to examine the role of clusterin in progression of steatohepatitis in mice fed a methionine and choline deficient (MCD) diet. We generated hepatocyte-specific clusterin overexpression (hCLU-tg) mice, and hCLU-tg mice showed lower levels of hepatic triglycerides, less infiltration of macrophages and reduction of TNF-α, activation of Nrf-2 than wild-type littermates fed the MCD diet. Also, sustained clusterin expression in liver ameliorated hepatic fibrogenesis by reducing the activation of hepatic stellate cells by MCD diet. Sustained expression of clusterin in liver functioned as a preconditioning stimulus and prevented MCD diet-induced severe steatohepatitis injury via Nrf2 activation. These results demonstrate a novel function of clusterin as an immune preconditioning regulator in various inflammatory diseases including steatohepatitis.


Assuntos
Clusterina/metabolismo , Hepatócitos/metabolismo , Hepatopatia Gordurosa não Alcoólica/prevenção & controle , Animais , Deficiência de Colina/complicações , Deficiência de Colina/metabolismo , Clusterina/genética , Dieta/efeitos adversos , Modelos Animais de Doenças , Fígado/metabolismo , Fígado/patologia , Masculino , Metionina/deficiência , Camundongos , Camundongos Transgênicos , Fator 2 Relacionado a NF-E2/metabolismo , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/metabolismo , Estresse Oxidativo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Regulação para Cima
5.
Int J Med Inform ; 109: 55-69, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29195707

RESUMO

Medical students should be able to actively apply clinical reasoning skills to further their interpretative, diagnostic, and treatment skills in a non-obtrusive and scalable way. Case-Based Learning (CBL) approach has been receiving attention in medical education as it is a student-centered teaching methodology that exposes students to real-world scenarios that need to be solved using their reasoning skills and existing theoretical knowledge. In this paper, we propose an interactive CBL System, called iCBLS, which supports the development of collaborative clinical reasoning skills for medical students in an online environment. The iCBLS consists of three modules: (i) system administration (SA), (ii) clinical case creation (CCC) with an innovative semi-automatic approach, and (iii) case formulation (CF) through intervention of medical students' and teachers' knowledge. Two evaluations under the umbrella of the context/input/process/product (CIPP) model have been performed with a Glycemia study. The first focused on the system satisfaction, evaluated by 54 students. The latter aimed to evaluate the system effectiveness, simulated by 155 students. The results show a high success rate of 70% for students' interaction, 76.4% for group learning, 72.8% for solo learning, and 74.6% for improved clinical skills.


Assuntos
Educação Médica/organização & administração , Aprendizagem Baseada em Problemas , Treinamento por Simulação , Estudantes de Medicina/psicologia , Ensino/organização & administração , Competência Clínica , Humanos , Aprendizagem
6.
Artif Intell Med ; 92: 51-70, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-26573247

RESUMO

OBJECTIVE: The objective of this study is to help a team of physicians and knowledge engineers acquire clinical knowledge from existing practices datasets for treatment of head and neck cancer, to validate the knowledge against published guidelines, to create refined rules, and to incorporate these rules into clinical workflow for clinical decision support. METHODS AND MATERIALS: A team of physicians (clinical domain experts) and knowledge engineers adapt an approach for modeling existing treatment practices into final executable clinical models. For initial work, the oral cavity is selected as the candidate target area for the creation of rules covering a treatment plan for cancer. The final executable model is presented in HL7 Arden Syntax, which helps the clinical knowledge be shared among organizations. We use a data-driven knowledge acquisition approach based on analysis of real patient datasets to generate a predictive model (PM). The PM is converted into a refined-clinical knowledge model (R-CKM), which follows a rigorous validation process. The validation process uses a clinical knowledge model (CKM), which provides the basis for defining underlying validation criteria. The R-CKM is converted into a set of medical logic modules (MLMs) and is evaluated using real patient data from a hospital information system. RESULTS: We selected the oral cavity as the intended site for derivation of all related clinical rules for possible associated treatment plans. A team of physicians analyzed the National Comprehensive Cancer Network (NCCN) guidelines for the oral cavity and created a common CKM. Among the decision tree algorithms, chi-squared automatic interaction detection (CHAID) was applied to a refined dataset of 1229 patients to generate the PM. The PM was tested on a disjoint dataset of 739 patients, which gives 59.0% accuracy. Using a rigorous validation process, the R-CKM was created from the PM as the final model, after conforming to the CKM. The R-CKM was converted into four candidate MLMs, and was used to evaluate real data from 739 patients, yielding efficient performance with 53.0% accuracy. CONCLUSION: Data-driven knowledge acquisition and validation against published guidelines were used to help a team of physicians and knowledge engineers create executable clinical knowledge. The advantages of the R-CKM are twofold: it reflects real practices and conforms to standard guidelines, while providing optimal accuracy comparable to that of a PM. The proposed approach yields better insight into the steps of knowledge acquisition and enhances collaboration efforts of the team of physicians and knowledge engineers.


Assuntos
Inteligência Artificial , Sistemas de Apoio a Decisões Clínicas/organização & administração , Sistemas Inteligentes , Neoplasias de Cabeça e Pescoço/terapia , Sistemas de Informação/organização & administração , Algoritmos , Humanos , Sistemas de Informação/normas , Informática Médica , Guias de Prática Clínica como Assunto , Linguagens de Programação , Fluxo de Trabalho
7.
Comput Methods Programs Biomed ; 150: 41-72, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28859829

RESUMO

OBJECTIVE: Technologically integrated healthcare environments can be realized if physicians are encouraged to use smart systems for the creation and sharing of knowledge used in clinical decision support systems (CDSS). While CDSSs are heading toward smart environments, they lack support for abstraction of technology-oriented knowledge from physicians. Therefore, abstraction in the form of a user-friendly and flexible authoring environment is required in order for physicians to create shareable and interoperable knowledge for CDSS workflows. Our proposed system provides a user-friendly authoring environment to create Arden Syntax MLM (Medical Logic Module) as shareable knowledge rules for intelligent decision-making by CDSS. METHODS AND MATERIALS: Existing systems are not physician friendly and lack interoperability and shareability of knowledge. In this paper, we proposed Intelligent-Knowledge Authoring Tool (I-KAT), a knowledge authoring environment that overcomes the above mentioned limitations. Shareability is achieved by creating a knowledge base from MLMs using Arden Syntax. Interoperability is enhanced using standard data models and terminologies. However, creation of shareable and interoperable knowledge using Arden Syntax without abstraction increases complexity, which ultimately makes it difficult for physicians to use the authoring environment. Therefore, physician friendliness is provided by abstraction at the application layer to reduce complexity. This abstraction is regulated by mappings created between legacy system concepts, which are modeled as domain clinical model (DCM) and decision support standards such as virtual medical record (vMR) and Systematized Nomenclature of Medicine - Clinical Terms (SNOMED CT). We represent these mappings with a semantic reconciliation model (SRM). RESULTS: The objective of the study is the creation of shareable and interoperable knowledge using a user-friendly and flexible I-KAT. Therefore we evaluated our system using completeness and user satisfaction criteria, which we assessed through the system- and user-centric evaluation processes. For system-centric evaluation, we compared the implementation of clinical information modelling system requirements in our proposed system and in existing systems. The results suggested that 82.05% of the requirements were fully supported, 7.69% were partially supported, and 10.25% were not supported by our system. In the existing systems, 35.89% of requirements were fully supported, 28.20% were partially supported, and 35.89% were not supported. For user-centric evaluation, the assessment criterion was 'ease of use'. Our proposed system showed 15 times better results with respect to MLM creation time than the existing systems. Moreover, on average, the participants made only one error in MLM creation using our proposed system, but 13 errors per MLM using the existing systems. CONCLUSION: We provide a user-friendly authoring environment for creation of shareable and interoperable knowledge for CDSS to overcome knowledge acquisition complexity. The authoring environment uses state-of-the-art decision support-related clinical standards with increased ease of use.


Assuntos
Tomada de Decisão Clínica , Sistemas de Apoio a Decisões Clínicas , Bases de Conhecimento , Humanos
8.
Biochem Biophys Res Commun ; 482(4): 1407-1412, 2017 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-27965092

RESUMO

Clusterin is a secretory glycoprotein that is up-regulated in areas of inflammation and under increased levels of oxidative stress. Previously, we demonstrated that clusterin activates NF-κB, and up-regulates the expression of MMP-9 and TNF-α. In this research, we extend our previous findings by reporting that such clusterin-induced macrophage response is mediated via TLR4 signaling. Specifically, we found that TNF-α induced by clusterin was significantly abrogated by pretreatment of TLR4-signaling inhibitors and anti-TLR4 neutralizing antibody. Additionally, a primary culture of macrophages derived from TLR4-signal defective and knockout mice were unresponsive to clusterin, resulting in no TNF-α secretion, whereas macrophages carrying wild-type TLR4 responded to clusterin and induced TNF-α. Moreover, clusterin increased NF-κB promoter activity in HEK-Blue hTLR4 cells, but not in HEK-Blue Null2 cells. To confirm that clusterin elicits TLR4 signal transduction, recombinant clusterin was generated and purified from cell culture. Interestingly, we found that the recombinant clusterin with C-terminal HA-tag induces TNF-α secretion at a significantly lower level compared to an intact form of clusterin without C-terminal HA-tag. Removal of HA-tag from the recombinant clusterin restored its activity, suggesting that C-terminal HA-tag partially masks the domain involved in TLR4 signaling. Furthermore, clusterin enhanced TLR4 mobilization into lipid raft of plasma membrane, and TNF-α and MMP-9 secretion stimulated by clusterin was diminished by pretreatment with methyl-ß-cyclodextrin (MßCD), which was used to disrupt lipid raft. In conclusion, clusterin-induced TNF-α and MMP-9 up-regulation is most likely mediated via TLR4 recruitment into lipid rafts, and these data describe a novel role of clusterin as an endogenous regulator for TLR4 signaling.


Assuntos
Clusterina/metabolismo , Macrófagos/metabolismo , Transdução de Sinais , Receptor 4 Toll-Like/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Humanos , Inflamação , Macrófagos/citologia , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Microdomínios da Membrana/química , Camundongos , Camundongos Endogâmicos C3H , Camundongos Knockout , NF-kappa B/metabolismo , Estresse Oxidativo , Domínios Proteicos , Células RAW 264.7
9.
Biomed Eng Online ; 15 Suppl 1: 76, 2016 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-27454608

RESUMO

BACKGROUND: The provision of health and wellness care is undergoing an enormous transformation. A key element of this revolution consists in prioritizing prevention and proactivity based on the analysis of people's conducts and the empowerment of individuals in their self-management. Digital technologies are unquestionably destined to be the main engine of this change, with an increasing number of domain-specific applications and devices commercialized every year; however, there is an apparent lack of frameworks capable of orchestrating and intelligently leveraging, all the data, information and knowledge generated through these systems. METHODS: This work presents Mining Minds, a novel framework that builds on the core ideas of the digital health and wellness paradigms to enable the provision of personalized support. Mining Minds embraces some of the most prominent digital technologies, ranging from Big Data and Cloud Computing to Wearables and Internet of Things, as well as modern concepts and methods, such as context-awareness, knowledge bases or analytics, to holistically and continuously investigate on people's lifestyles and provide a variety of smart coaching and support services. RESULTS: This paper comprehensively describes the efficient and rational combination and interoperation of these technologies and methods through Mining Minds, while meeting the essential requirements posed by a framework for personalized health and wellness support. Moreover, this work presents a realization of the key architectural components of Mining Minds, as well as various exemplary user applications and expert tools to illustrate some of the potential services supported by the proposed framework. CONCLUSIONS: Mining Minds constitutes an innovative holistic means to inspect human behavior and provide personalized health and wellness support. The principles behind this framework uncover new research ideas and may serve as a reference for similar initiatives.


Assuntos
Mineração de Dados/métodos , Promoção da Saúde/métodos , Internet , Comportamentos Relacionados com a Saúde , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Invenções , Estilo de Vida , Aplicativos Móveis
10.
Sensors (Basel) ; 15(9): 21294-314, 2015 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-26343669

RESUMO

Finding appropriate evidence to support clinical practices is always challenging, and the construction of a query to retrieve such evidence is a fundamental step. Typically, evidence is found using manual or semi-automatic methods, which are time-consuming and sometimes make it difficult to construct knowledge-based complex queries. To overcome the difficulty in constructing knowledge-based complex queries, we utilized the knowledge base (KB) of the clinical decision support system (CDSS), which has the potential to provide sufficient contextual information. To automatically construct knowledge-based complex queries, we designed methods to parse rule structure in KB of CDSS in order to determine an executable path and extract the terms by parsing the control structures and logic connectives used in the logic. The automatically constructed knowledge-based complex queries were executed on the PubMed search service to evaluate the results on the reduction of retrieved citations with high relevance. The average number of citations was reduced from 56,249 citations to 330 citations with the knowledge-based query construction approach, and relevance increased from 1 term to 6 terms on average. The ability to automatically retrieve relevant evidence maximizes efficiency for clinicians in terms of time, based on feedback collected from clinicians. This approach is generally useful in evidence-based medicine, especially in ambient assisted living environments where automation is highly important.


Assuntos
Sistemas de Apoio a Decisões Clínicas , Registros Eletrônicos de Saúde , Armazenamento e Recuperação da Informação/métodos , Bases de Conhecimento , Software , Inteligência Artificial , Moradias Assistidas , Doença Crônica/terapia , Serviços de Assistência Domiciliar , Humanos , MEDLINE , Neoplasias/terapia
11.
Sensors (Basel) ; 15(7): 15772-98, 2015 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-26147731

RESUMO

A wide array of biomedical data are generated and made available to healthcare experts. However, due to the diverse nature of data, it is difficult to predict outcomes from it. It is therefore necessary to combine these diverse data sources into a single unified dataset. This paper proposes a global unified data model (GUDM) to provide a global unified data structure for all data sources and generate a unified dataset by a "data modeler" tool. The proposed tool implements user-centric priority based approach which can easily resolve the problems of unified data modeling and overlapping attributes across multiple datasets. The tool is illustrated using sample diabetes mellitus data. The diverse data sources to generate the unified dataset for diabetes mellitus include clinical trial information, a social media interaction dataset and physical activity data collected using different sensors. To realize the significance of the unified dataset, we adopted a well-known rough set theory based rules creation process to create rules from the unified dataset. The evaluation of the tool on six different sets of locally created diverse datasets shows that the tool, on average, reduces 94.1% time efforts of the experts and knowledge engineer while creating unified datasets.


Assuntos
Sistemas de Gerenciamento de Base de Dados , Armazenamento e Recuperação da Informação/métodos , Aplicações da Informática Médica , Ensaios Clínicos como Assunto , Humanos , Mídias Sociais
12.
Biochem Biophys Res Commun ; 445(3): 645-50, 2014 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-24569077

RESUMO

Clusterin induces the expression of various chemotactic cytokines including tumor necrosis factor-α (TNF-α) in macrophages and is involved in the cell migration. According to the results of this study, clusterin induced the directional migration (chemotaxis) of macrophages based on a checkerboard analysis. The chemotactic activity of clusterin was prevented by pretreatment with pertussis toxin (PTX), indicating that the Gαi/o-protein coupled receptor (GPCR) was involved in the chemotactic response of clusterin. Clusterin-stimulated chemotaxis was abrogated in a dose-dependent manner by pretreatment with gallein (a Gßγ inhibitor), indicating the involvement of Gßγ released from the GPCR. In addition, inhibitors of phospholipase C (PLC, U73122) and phosphoinositide 3-kinase (PI3K, LY294002), the key targets of Gßγ binding and activation, suppressed chemotactic migration by clusterin. The phosphorylation of Akt induced by clusterin was blocked by pretreatment with gallein or LY294002 but not with U73122, indicating that Gßγ released from the PTX-sensitive Gi protein complex activated PLC and PI3K/Akt signaling pathways separately. The activation of cellular MAP kinases was essential in that their inhibitors blocked clusterin-induced chemotaxis, and Gßγ was required for the activation of MAP kinases because gallein reduced their phosphorylations induced by clusterin. In addition, the inflammation-induced migration of macrophages was greatly reduced in clusterin-deficient mice based on a thioglycollate-induced peritonitis model system. These results suggest that clusterin stimulates the chemotactic migration of macrophages through a PTX-sensitive GPCR and Gßγ-dependent pathways and describe a novel role of clusterin as a chemoattractant of monocytes/macrophages, suggesting that clusterin may serve as a molecular bridge between inflammation and its remodeling of related tissue by recruiting immune cells.


Assuntos
Quimiotaxia , Clusterina/metabolismo , Macrófagos/citologia , Receptores Acoplados a Proteínas G/metabolismo , Animais , Quimiotaxia/efeitos dos fármacos , Humanos , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Toxina Pertussis/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Transdução de Sinais , Fosfolipases Tipo C/antagonistas & inibidores , Fosfolipases Tipo C/metabolismo
13.
Biochem Biophys Res Commun ; 422(1): 200-5, 2012 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-22575505

RESUMO

Tumor associated macrophages are known to be closely linked with tumor progression and metastasis. On the other hand, clusterin is overexpressed in several tumor types and regarded as a putative tumor-promoting factor due to this overexpression and the subsequent induction of chemoresistance. In our previous study, clusterin was found to induce the expression of matrix metalloproteinase-9 (MMP-9) in macrophages, and MMP-9 is known to be essential for tumor cell migration and invasion via basement membrane breakdown. Because paracrine interactions between tumor cells and surrounding macrophages regulate metastasis, these findings raise the possibility that clusterin promotes the secretion of cytokines in macrophages in addition to MMP-9. Here, we demonstrate that clusterin upregulates the expressions of chemotactic cytokines, that is, monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein-1ß (MIP-1ß), regulated upon activation, normal T cell expressed and secreted (RANTES), and tumor necrosis factor-α (TNF-α) in Raw264.7 macrophages. In particular, clusterin stimulated TNF-α secretion via the activations of ERK, JNK, and PI3K/Akt pathways in a time and dose-dependent manner. Furthermore, clusterin-induced TNF-α secretion was found to play a critical role in the chemotactic migration of Raw264.7 macrophages. It was also found that clusterin acts directly as a chemoattractant for macrophages. Together, these results suggest that clusterin stimulates the expression and secretion of TNF-α, which plays a critical role in promoting macrophage chemotaxis, via ERK, JNK, and PI3K/Akt pathways. Collectively, these findings describe a novel function for clusterin as an inducer of TNF-α in macrophages and their chemotactic migration, and suggest that clusterin has a tumor-promoting effect.


Assuntos
Quimiotaxia/fisiologia , Clusterina/fisiologia , Macrófagos Peritoneais/fisiologia , Fator de Necrose Tumoral alfa/metabolismo , Animais , Linhagem Celular , Quimiotaxia/efeitos dos fármacos , Clusterina/farmacologia , MAP Quinase Quinase 4/biossíntese , Sistema de Sinalização das MAP Quinases , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/metabolismo , Camundongos , Neoplasias/metabolismo , Neoplasias/patologia , Fosfatidilinositol 3-Quinases/biossíntese , Proteínas Proto-Oncogênicas c-akt/biossíntese , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/genética
14.
Biochem Biophys Res Commun ; 420(4): 851-6, 2012 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-22465014

RESUMO

Clusterin is a disulfide-linked heterodimeric glycoprotein that has been implicated in a variety of biological processes. Its expression has been shown to be elevated during cellular senescence and normal aging, but it is uncertain whether clusterin protects against aging or whether its expression is a consequence of aging. To investigate the functions of clusterin during organismal aging, we established transgenic Drosophila alleles to induce the expression of the secretory form of human clusterin (hClu(S)) using the Gal4/UAS system. hClu(S) protein (~60 kDa) was detected in both adult homogenates and larval hemolymphs of flies ubiquitously overexpressing hClu(S) (da-Gal4>UAS-hClu(S)) and in motoneurons (D42-Gal4>UAS-hClu(S)). Interestingly, the mean lifespans of these hClu(S)-overexpressing flies were significantly greater than those of control flies that exhibited no hClu(S) induction. hClu(S)-overexpressing flies also showed significantly greater tolerance to heat shock, wet starvation, and oxidative stress. Furthermore, amounts of reactive oxygen species (ROS) in whole bodies were significantly lower in hClu(S)-overexpressing flies. In addition, clusterin was found to prevent the inactivation of glutamine synthetase (GS) by metal-catalyzed oxidation (MCO) in vitro, and this protection was only supported by thiol-reducing equivalents, such as, DTT or GSH, and not by ascorbate (a non-thiol MCO system). Furthermore, this protection against GS inactivation by clusterin was abolished by reacting clusterin with N-ethylmaleimide, a sulfhydryl group-modifying agent. Taken together, these results suggest that a disulfide-linked form of clusterin functions as an antioxidant protein via its cysteine sulfhydryl groups to reduce ROS levels and delay the organismal aging in fruit flies.


Assuntos
Clusterina/fisiologia , Drosophila melanogaster/fisiologia , Resposta ao Choque Térmico/genética , Longevidade/genética , Estresse Oxidativo/genética , Animais , Animais Geneticamente Modificados/genética , Animais Geneticamente Modificados/fisiologia , Clusterina/genética , Ditiotreitol/farmacologia , Proteínas de Drosophila , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/genética , Etilmaleimida/farmacologia , Glutamato-Amônia Ligase , Hemolinfa/metabolismo , Humanos , Longevidade/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo
15.
J Leukoc Biol ; 90(4): 761-9, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21742938

RESUMO

Most solid tumor tissues possess a significant population of macrophages, which are known to be closely linked with tumor progression and metastasis. Clusterin has been reported to be overexpressed in various tumors and to have a tumor-promoting role. As clusterin induction and macrophage infiltration occur concurrently at the tumor site, it raises a possibility that clusterin may regulate the function of macrophages via facilitating ECM remodeling. Here, we demonstrate for the first time the expression of MMP-9 by clusterin in human primary monocytes as well as human and murine macrophage cell lines, THP-1, and Raw264.7. MMP-9 expression was accompanied by increased enzymatic activity, as revealed by gelatin zymography. The MMP-9 activity promoted by clusterin was found to be dependent on the activation of ERK1/2 and PI3K/Akt but not p38 or JNK pathways. Inhibition of PI3K activity did not affect the activation of ERK1/2 and vice versa, indicating that the two pathways were independently operated to stimulate MMP-9 activity. Moreover, clusterin facilitated nuclear translocation of NF-κB p65 along with IκB-α degradation and phosphorylation, which was critical for MMP-9 expression. As NF-κB is a central regulator of inflammation, clusterin may provide a molecular link between inflammation and cancer via up-regulating NF-κB and MMP-9. Collectively, these data highlight a novel role of clusterin as a stimulator for MMP-9 expression in macrophages, which may contribute to the tissue reorganization by serving as a modulator for ECM degradation.


Assuntos
Clusterina/metabolismo , Macrófagos/metabolismo , Metaloproteinase 9 da Matriz/biossíntese , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Monócitos/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fator de Transcrição RelA/metabolismo , Animais , Linhagem Celular , Clusterina/farmacologia , Indução Enzimática , Humanos , MAP Quinase Quinase 4/metabolismo , Camundongos , Neoplasias/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
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