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1.
PLoS Pathog ; 18(11): e1010656, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36374839

RESUMO

Pore-forming proteins (PFPs) comprise the largest single class of bacterial protein virulence factors and are expressed by many human and animal bacterial pathogens. Cells that are attacked by these virulence factors activate epithelial intrinsic cellular defenses (or INCEDs) to prevent the attendant cellular damage, cellular dysfunction, osmotic lysis, and organismal death. Several conserved PFP INCEDs have been identified using the nematode Caenorhabditis elegans and the nematicidal PFP Cry5B, including mitogen-activated protein kinase (MAPK) signaling pathways. Here we demonstrate that the gene nck-1, which has homologs from Drosophila to humans and links cell signaling with localized F-actin polymerization, is required for INCED against small-pore PFPs in C. elegans. Reduction/loss of nck-1 function results in C. elegans hypersensitivity to PFP attack, a hallmark of a gene required for INCEDs against PFPs. This requirement for nck-1-mediated INCED functions cell-autonomously in the intestine and is specific to PFPs but not to other tested stresses. Genetic interaction experiments indicate that nck-1-mediated INCED against PFP attack is independent of the major MAPK PFP INCED pathways. Proteomics and cell biological and genetic studies further indicate that nck-1 functions with F-actin cytoskeleton modifying genes like arp2/3, erm-1, and dbn-1 and that nck-1/arp2/3 promote pore repair at the membrane surface and protect against PFP attack independent of p38 MAPK. Consistent with these findings, PFP attack causes significant changes in the amount of actin cytoskeletal proteins and in total amounts of F-actin in the target tissue, the intestine. nck-1 mutant animals appear to have lower F-actin levels than wild-type C. elegans. Studies on nck-1 and other F-actin regulating proteins have uncovered a new and important role of this pathway and the actin cytoskeleton in PFP INCED and protecting an intestinal epithelium in vivo against PFP attack.


Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Animais , Humanos , Caenorhabditis elegans/microbiologia , Actinas/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Fatores de Virulência/metabolismo , Porinas/metabolismo , Citoesqueleto de Actina/metabolismo
2.
Proc Natl Acad Sci U S A ; 115(41): 10381-10386, 2018 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-30254164

RESUMO

Nuclear hormone receptors (NRs), such as retinoic acid receptors (RARs), play critical roles in vertebrate development and homeostasis by regulating target gene transcription. Their activity is controlled by ligand-dependent release of corepressors and subsequent recruitment of coactivators, but how these individual receptor modes contribute to development are unknown. Here, we show that mice carrying targeted knockin mutations in the corepressor Silencing Mediator of Retinoid and Thyroid hormone receptor (SMRT) that specifically disable SMRT function in NR signaling (SMRTmRID), display defects in cranial neural crest cell-derived structures and posterior homeotic transformations of axial vertebrae. SMRTmRID embryos show enhanced transcription of RAR targets including Hox loci, resulting in respecification of vertebral identities. Up-regulated histone acetylation and decreased H3K27 methylation are evident in the Hox loci whose somitic expression boundaries are rostrally shifted. Furthermore, enhanced recruitment of super elongation complex is evident in rapidly induced non-Pol II-paused targets in SMRTmRID embryonic stem cells. These results demonstrate that SMRT-dependent repression of RAR is critical to establish and maintain the somitic Hox code and segmental identity during fetal development via epigenetic marking of target loci.


Assuntos
Regulação da Expressão Gênica , Genes Homeobox/genética , Correpressor 2 de Receptor Nuclear/fisiologia , Somitos/fisiologia , Transcrição Gênica , Tretinoína/farmacologia , Animais , Antineoplásicos/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Crista Neural/citologia , Crista Neural/fisiologia , Somitos/citologia , Somitos/efeitos dos fármacos
3.
Nature ; 513(7518): 436-9, 2014 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-25043058

RESUMO

Fibroblast growth factor 1 (FGF1) is an autocrine/paracrine regulator whose binding to heparan sulphate proteoglycans effectively precludes its circulation. Although FGF1 is known as a mitogenic factor, FGF1 knockout mice develop insulin resistance when stressed by a high-fat diet, suggesting a potential role in nutrient homeostasis. Here we show that parenteral delivery of a single dose of recombinant FGF1 (rFGF1) results in potent, insulin-dependent lowering of glucose levels in diabetic mice that is dose-dependent but does not lead to hypoglycaemia. Chronic pharmacological treatment with rFGF1 increases insulin-dependent glucose uptake in skeletal muscle and suppresses the hepatic production of glucose to achieve whole-body insulin sensitization. The sustained glucose lowering and insulin sensitization attributed to rFGF1 are not accompanied by the side effects of weight gain, liver steatosis and bone loss associated with current insulin-sensitizing therapies. We also show that the glucose-lowering activity of FGF1 can be dissociated from its mitogenic activity and is mediated predominantly via FGF receptor 1 signalling. Thus we have uncovered an unexpected, neomorphic insulin-sensitizing action for exogenous non-mitogenic human FGF1 with therapeutic potential for the treatment of insulin resistance and type 2 diabetes.


Assuntos
Fator 1 de Crescimento de Fibroblastos/farmacologia , Glucose/metabolismo , Insulina/metabolismo , Animais , Glicemia/metabolismo , Peso Corporal/efeitos dos fármacos , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Dieta Hiperlipídica , Relação Dose-Resposta a Droga , Fator 1 de Crescimento de Fibroblastos/administração & dosagem , Fator 1 de Crescimento de Fibroblastos/efeitos adversos , Teste de Tolerância a Glucose , Humanos , Resistência à Insulina , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Mitógenos/farmacologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/metabolismo
4.
Nature ; 485(7398): 391-4, 2012 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-22522926

RESUMO

Although feast and famine cycles illustrate that remodelling of adipose tissue in response to fluctuations in nutrient availability is essential for maintaining metabolic homeostasis, the underlying mechanisms remain poorly understood. Here we identify fibroblast growth factor 1 (FGF1) as a critical transducer in this process in mice, and link its regulation to the nuclear receptor PPARγ (peroxisome proliferator activated receptor γ), which is the adipocyte master regulator and the target of the thiazolidinedione class of insulin sensitizing drugs. FGF1 is the prototype of the 22-member FGF family of proteins and has been implicated in a range of physiological processes, including development, wound healing and cardiovascular changes. Surprisingly, FGF1 knockout mice display no significant phenotype under standard laboratory conditions. We show that FGF1 is highly induced in adipose tissue in response to a high-fat diet and that mice lacking FGF1 develop an aggressive diabetic phenotype coupled to aberrant adipose expansion when challenged with a high-fat diet. Further analysis of adipose depots in FGF1-deficient mice revealed multiple histopathologies in the vasculature network, an accentuated inflammatory response, aberrant adipocyte size distribution and ectopic expression of pancreatic lipases. On withdrawal of the high-fat diet, this inflamed adipose tissue fails to properly resolve, resulting in extensive fat necrosis. In terms of mechanisms, we show that adipose induction of FGF1 in the fed state is regulated by PPARγ acting through an evolutionarily conserved promoter proximal PPAR response element within the FGF1 gene. The discovery of a phenotype for the FGF1 knockout mouse establishes the PPARγ­FGF1 axis as critical for maintaining metabolic homeostasis and insulin sensitization.


Assuntos
Fator 1 de Crescimento de Fibroblastos/genética , Fator 1 de Crescimento de Fibroblastos/metabolismo , Homeostase , Gordura Intra-Abdominal/metabolismo , PPAR gama/metabolismo , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Adipócitos/patologia , Animais , Sequência de Bases , Tamanho Celular/efeitos dos fármacos , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/patologia , Dieta Hiperlipídica/efeitos adversos , Fator 1 de Crescimento de Fibroblastos/deficiência , Homeostase/efeitos dos fármacos , Humanos , Inflamação/genética , Insulina/metabolismo , Resistência à Insulina , Gordura Intra-Abdominal/efeitos dos fármacos , Gordura Intra-Abdominal/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Necrose/enzimologia , Regiões Promotoras Genéticas/genética , Elementos de Resposta/genética
6.
ScientificWorldJournal ; 2014: 957391, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25126608

RESUMO

Maji et al. introduced the concept of fuzzy soft sets as a generalization of the standard soft sets and presented an application of fuzzy soft sets in a decision making problem. The aim of this paper is to apply the concept of fuzzy soft sets to n-ary hypergroup theory. The concepts of (∈(γ), ∈(γ) ∨ q(δ))-fuzzy soft (invertible) n-ary subhypergroups over a commutative n-ary hypergroup are introduced and some related properties and characterizations are obtained. The homomorphism properties of (∈(γ), ∈(γ) ∨ q(δ))-fuzzy soft (invertible) n-ary subhypergroups are also derived.


Assuntos
Tomada de Decisões , Modelos Teóricos , Análise Numérica Assistida por Computador , Simulação por Computador , Lógica Fuzzy
7.
ScientificWorldJournal ; 2014: 975474, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25157379

RESUMO

The aim of this paper is to introduce the concepts of fuzzy strong h-ideals and fuzzy congruences of hemirings. The quotient hemirings via fuzzy strong h-ideals are investigated. The relationships between fuzzy congruences and fuzzy strong h-ideals of hemirings are discussed. Pay attention to an open question on fuzzy congruences. Finally, the normal fuzzy strong h-ideals of hemirings are explored.


Assuntos
Algoritmos , Modelos Teóricos
8.
ScientificWorldJournal ; 2014: 673563, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25097884

RESUMO

Quality function deployment (QFD) can provide a means of translating customer requirements (CRs) into engineering characteristics (ECs) for each stage of product development and production. The main objective of QFD-based product planning is to determine the target levels of ECs for a new product or service. QFD is a breakthrough tool which can effectively reduce the gap between CRs and a new product/service. Even though there are conflicts among some ECs, the objective of developing new product is to maximize the overall customer satisfaction. Therefore, there may be room for cooperation among ECs. A cooperative game framework combined with fuzzy set theory is developed to determine the target levels of the ECs in QFD. The key to develop the model is the formulation of the bargaining function. In the proposed methodology, the players are viewed as the membership functions of ECs to formulate the bargaining function. The solution for the proposed model is Pareto-optimal. An illustrated example is cited to demonstrate the application and performance of the proposed approach.


Assuntos
Comportamento do Consumidor , Modelos Teóricos
9.
ScientificWorldJournal ; 2014: 471016, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25009829

RESUMO

This study considers a scheduling environment in which there are two agents and a set of jobs, each of which belongs to one of the two agents and its actual processing time is defined as a decreasing linear function of its starting time. Each of the two agents competes to process its respective jobs on a single machine and has its own scheduling objective to optimize. The objective is to assign the jobs so that the resulting schedule performs well with respect to the objectives of both agents. The objective functions addressed in this study include the maximum cost, the total weighted completion time, and the discounted total weighted completion time. We investigate three problems arising from different combinations of the objectives of the two agents. The computational complexity of the problems is discussed and solution algorithms where possible are presented.


Assuntos
Algoritmos , Inteligência Artificial , Simulação por Computador
10.
Proc Natl Acad Sci U S A ; 107(8): 3558-63, 2010 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-20133714

RESUMO

Although adipose tissue is an expandable and readily attainable source of proliferating, multipotent stem cells, its potential for use in regenerative medicine has not been extensively explored. Here we report that adult human and mouse adipose-derived stem cells can be reprogrammed to induced pluripotent stem (iPS) cells with substantially higher efficiencies than those reported for human and mouse fibroblasts. Unexpectedly, both human and mouse iPS cells can be obtained in feeder-free conditions. We discovered that adipose-derived stem cells intrinsically express high levels of pluripotency factors such as basic FGF, TGFbeta, fibronectin, and vitronectin and can serve as feeders for both autologous and heterologous pluripotent cells. These results demonstrate a great potential for adipose-derived cells in regenerative therapeutics and as a model for studying the molecular mechanisms of feeder-free iPS generation and maintenance.


Assuntos
Tecido Adiposo/citologia , Células-Tronco Pluripotentes Induzidas/fisiologia , Animais , Quimera , Técnicas de Cocultura , Fatores de Crescimento de Fibroblastos , Fibroblastos/citologia , Fibroblastos/fisiologia , Fibronectinas/biossíntese , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fator de Crescimento Transformador alfa/biossíntese , Vitronectina/biossíntese
11.
Proc Natl Acad Sci U S A ; 106(52): 22504-9, 2009 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-20018750

RESUMO

Although peroxisome proliferator-activated receptor gamma (PPARgamma) agonists such as thiazolidinediones (TZDs) are widely used to treat type 2 diabetes, how its activation in individual tissues contributes to TZD's therapeutic action remains controversial. As TZDs are known to have receptor-independent effects, we sought to establish gain-of-function animal models to delineate the receptor's insulin-sensitizing actions. Unexpectedly, we find that selective activation of PPARgamma in adipocytes, but not in macrophages, is sufficient for whole-body insulin sensitization equivalent to systemic TZD treatment. In addition to improved adipokine, inflammatory, and lipid profiles, PPARgamma activation in mature adipocytes normalizes serum insulin without increased adipogenesis. Co-culture studies indicated that PPARgamma-activated adipocytes broadly suppress induction of inflammatory cytokines and C-X-C family chemokines in macrophages. Collectively, these data describe an "adipocentric" model in which adipose activation of PPARgamma is sufficient for complete insulin sensitization and suggest a specific application for fat selective PPARgamma modulators in diabetic therapy.


Assuntos
Adipócitos Brancos/metabolismo , Insulina/metabolismo , PPAR gama/metabolismo , Células 3T3-L1 , Adipócitos Brancos/efeitos dos fármacos , Animais , Linhagem Celular , Quimiocinas/genética , Quimiocinas/metabolismo , Expressão Gênica , Humanos , Hipoglicemiantes/farmacologia , Mediadores da Inflamação/metabolismo , Insulina/sangue , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Modelos Biológicos , PPAR gama/agonistas , PPAR gama/genética , Pioglitazona , Ratos , Ratos Zucker , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais , Tiazolidinedionas/farmacologia
12.
IEEE Trans Cybern ; 52(12): 12623-12637, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34546933

RESUMO

Skin lesion diagnosis is a key step for skin cancer screening, which requires high accuracy and interpretability. Though many computer-aided methods, especially deep learning methods, have made remarkable achievements in skin lesion diagnosis, their generalization and interpretability are still a challenge. To solve this issue, we propose an interpretability-based multimodal convolutional neural network (IM-CNN), which is a multiclass classification model with skin lesion images and metadata of patients as input for skin lesion diagnosis. The structure of IM-CNN consists of three main paths to deal with metadata, features extracted from segmented skin lesion with domain knowledge, and skin lesion images, respectively. We add interpretable visual modules to provide explanations for both images and metadata. In addition to area under the ROC curve (AUC), sensitivity, and specificity, we introduce a new indicator, an AUC curve with a sensitivity larger than 80% (AUC_SEN_80) for performance evaluation. Extensive experimental studies are conducted on the popular HAM10000 dataset, and the results indicate that the proposed model has overwhelming advantages compared with popular deep learning models, such as DenseNet, ResNet, and other state-of-the-art models for melanoma diagnosis. The proposed multimodal model also achieves on average 72% and 21% improvement in terms of sensitivity and AUC_SEN_80, respectively, compared with the single-modal model. The visual explanations can also help gain trust from dermatologists and realize man-machine collaborations, effectively reducing the limitation of black-box models in supporting medical decision making.


Assuntos
Diagnóstico por Computador , Redes Neurais de Computação , Humanos
13.
Sci Rep ; 9(1): 7868, 2019 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-31133690

RESUMO

Hookworms are one of the most prevalent and important parasites, infecting ~500 million people worldwide. Hookworm disease is among the leading causes of iron-deficiency anemia in the developing world and is associated with significant growth stunting and malnutrition. In humans, hookworms appear to impair memory and other forms of cognition, although definitive data are hard to come by. Here we study the impact of a human hookworm parasite, Ancylostoma ceylanicum, on cognition in hamsters in a controlled laboratory setting. We developed tests that measure long-term memory in hamsters. We find that hookworm-infected hamsters were fully capable of detecting a novel object. However, hookworm-infected hamsters were impaired in detecting a displaced object. Defects could be discerned at even at low levels of infection, whereas at higher levels of infection, hamsters were statistically unable to distinguish between displaced and non-displaced objects. These spatial memory deficiencies could not be attributed to defects in infected hamster mobility or to lack of interest. We also found that hookworm infection resulted in reproducible reductions in diversity and changes in specific taxanomic groups in the hamster gut microbiome. These data demonstrate that human hookworm infection in a laboratory mammal results in a specific, rapid, acute, and measurable deficit in spatial memory, and we speculate that gut alterations could play some role in these cognitive deficits. Our findings highlight the importance of hookworm elimination and suggest that finer tuned spatial memory studies be carried out in humans.


Assuntos
Ancylostoma/fisiologia , Ancilostomíase/microbiologia , Ancilostomíase/fisiopatologia , Cognição , Microbioma Gastrointestinal , Ancilostomíase/parasitologia , Animais , Cricetinae , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Memória de Longo Prazo
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