Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Int J Biochem Cell Biol ; 45(7): 1516-24, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23618877

RESUMO

The primary role of fibroblasts is production and degradation of extracellular matrix, and thus it helps in the structural framework of tissues. The close relation between fibroblast malfunction and many diseases such as chronic obstructive pulmonary disease, asthma, and fibrosis is widely accepted. Fibroblasts are known to respond to different growth factors and cytokines including platelet-derived growth factors (PDGF). However, the intracellular signaling mechanisms are not entirely clear. In addition to complex phosphorylation-driven signaling pathways, PDGF is also known to work through Ca(2+) signaling. We hypothesize that in human pulmonary fibroblasts, Ca(2+) waves play an important role in PDGF-mediated changes. To test this hypothesis, we treated human pulmonary fibroblasts, obtained from the lungs of ten donors, with PDGF acutely or overnight plus/minus a variety of blockers under various conditions. Ca(2+) waves were monitored by confocal [Ca(2+)]i fluorimetry, while gene expression of extracellular matrix genes was assessed via RT-PCR method. We found that both acute and overnight PDGF treatment evoked Ca(2+) waves. Removal of external Ca(2+) or depletion of internal Ca(2+) store using Cyclopiazonic acid (CPA) completely occluded PDGF-evoked Ca(2+) waves. Ryanodine, which blocks ryanodine receptor channels, had no effect on PDGF-evoked Ca(2+) wave, whereas the phospholipase C inhibitor U73122 and Xestospongin C, a potent IP3 receptor blocker, reduced the rapid PDGF-response to a relatively slowly-developing rise in [Ca(2+)]i. We also found that PDGF dramatically increased the expression of fibronectin1 and collagen A1 genes, which was reversed by the use of CPA or U73122. Our study indicates that, in human pulmonary fibroblasts, PDGF acts through IP3-induced Ca(2+)-release to trigger Ca(2+) waves, which in turn modulate gene expression of several matrix proteins.


Assuntos
Sinalização do Cálcio/fisiologia , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Fator de Crescimento Derivado de Plaquetas/metabolismo , Fosfolipases Tipo C/metabolismo , Idoso , Idoso de 80 Anos ou mais , Cálcio/metabolismo , Bloqueadores dos Canais de Cálcio , Sinalização do Cálcio/efeitos dos fármacos , Células Cultivadas , Colágeno Tipo I/biossíntese , Cadeia alfa 1 do Colágeno Tipo I , Estrenos , Matriz Extracelular/genética , Matriz Extracelular/metabolismo , Feminino , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fibronectinas/biossíntese , Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica , Humanos , Indóis , Receptores de Inositol 1,4,5-Trifosfato/antagonistas & inibidores , Pulmão/citologia , Compostos Macrocíclicos , Masculino , Pessoa de Meia-Idade , Oxazóis , Fator de Crescimento Derivado de Plaquetas/efeitos dos fármacos , Pirrolidinonas , Rianodina , Canal de Liberação de Cálcio do Receptor de Rianodina , Fosfolipases Tipo C/antagonistas & inibidores
2.
Am J Respir Cell Mol Biol ; 46(6): 757-64, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22268139

RESUMO

Fibroblasts maintain the structural framework of animal tissue by synthesizing extracellular matrix molecules. Chronic lung diseases are characterized in part by changes in fibroblast numbers, properties, and more. Fibroblasts respond to a variety of growth factors, cytokines, and proinflammatory mediators. However, the signaling mechanisms behind these responses have not been fully explored. We sought to determine the role of Ca(2+) waves in transforming growth factor-ß (TGF-ß)-mediated gene expression in human pulmonary fibroblasts. Primary human pulmonary fibroblasts were cultured and treated with TGF-ß and different blockers under various conditions. Cells were then loaded with the Ca(2+) indicator dye Oregon green, and Ca(2+) waves were monitored by confocal [Ca(2+)](i) fluorimetry. Real-time PCR was used to probe gene expression. TGF-ß (1 nM) evoked recurring Ca(2+) waves. A 30-minute pretreatment of SD 208, a TGF-ß receptor-1 kinase inhibitor, prevented Ca(2+) waves from being evoked by TGF-ß. The removal of external Ca(2+) completely occluded TGF-ß-evoked Ca(2+) waves. Cyclopiazonic acid, an inhibitor of the internal Ca(2+) pump, evoked a relatively slowly developing rise in Ca(2+) waves compared with the rapid changes evoked by TGF-ß, but the baseline fluorescence was increased. Ryanodine (10(-5) M) also blocked TGF-ß-mediated Ca(2+) wave activity. Real-time PCR showed that TGF-ß rapidly and dramatically increased the gene expression of collagen A1 and fibronectin. This increase was blocked by ryanodine treatment and cyclopiazonic acid. We conclude that, in human pulmonary fibroblasts, TGF-ß acts on ryanodine-sensitive channels, leading to Ca(2+) wave activity, which in turn amplifies extracellular matrix gene expression.


Assuntos
Cálcio/metabolismo , Regulação da Expressão Gênica/fisiologia , Pulmão/metabolismo , Fator de Crescimento Transformador beta/fisiologia , Western Blotting , Fibroblastos/metabolismo , Humanos , Pulmão/citologia , Reação em Cadeia da Polimerase em Tempo Real
3.
Artigo em Inglês | MEDLINE | ID: mdl-15115127

RESUMO

To study the genetic variability of DEN-4 Chinese isolates, and to trace the origin of DV4 Chinese isolates, we cloned and sequenced the NS2a-NS2b junction of 5 isolates and prototype DV4 (H-241). Our results show that isolates from the 1990 Guangdong epidemic, which were isolated in the early, middle, and late periods of the epidemic, share the same sequence in the NS2a-NS2b junction. The sequence similarity between isolates from the Guangdong epidemic in 1990 and DV4 H-241 is 96%; these isolates can be grouped into genotype I. The sequence similarity between the isolate from the Guangdong epidemic in 1987 and Dominica strain 814669 is 96%; this isolate can be grouped into genotype II. For the first time, our results show that there are also 2 DV4 genotypes in the Guangdong area of southern China, and these isolates perhaps were introduced from other epidemic areas outside of China.


Assuntos
Vírus da Dengue/genética , Dengue/virologia , Surtos de Doenças , Variação Genética , Proteínas não Estruturais Virais/genética , Sequência de Bases , Linhagem Celular , China/epidemiologia , DNA Complementar/análise , Dengue/epidemiologia , Humanos , Dados de Sequência Molecular
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...