Remodelamento parenquimatoso pulmonar em dois modelos experimentais de fibrose
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Data
2012-11-21
Autores
Fabro, Alexandre Todorovic [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A fibrose pulmonar é a base patológica de uma variedade de doenças crônicas incuráveis. A IL-17A, uma glicoproteína secretada de células Th17, é uma citocina pró-fibrótica relacionada recentemente à síntese de colágeno V e fibrose pulmonar. O remodelamento parenquimatoso pulmonar da matriz extracelular pelo colágeno I e V, apoptose e resposta Th17 foi estudado em camundongos Balb/c, C57/B6J selvagens e com knockout para o receptor A da IL-17; para determinar as vias fisiopatológicas que prolongam a fase tardia do processo fibrótico induzido por bleomicina e paraquat. Microscopia eletrônica, imunofluorescência, imunohistoquímica, detecção in situ da apoptose, morfometria, reconstrução tridimensional e reação em cadeia da polimerase em tempo real foram usados para avaliar a quantidade, estrutura e cadeias moleculares dos tipos de colágenos, apoptose e células imunes. Verificamos um aumento da síntese e secreção do colágeno V que promove a perpetuação da fibrose pulmonar de maneira IL-17A dependente. Além disso, observou-se que marcadores críticos da resposta Th17 como IL17, STAT3, TGF-β, IL-6, IL- 21, IL-23 e células T CD4+ foram significantemente aumentados em cepas susceptíveis a fibrose pulmonar e intensificadas na ausência do receptor A da IL-17. O aumento de marcadores Th17 resulta em um aumento de células T CD4+ através de uma resposta imune que efetivamente bloqueia a degradação do colágeno V, o qual contribui para o bloqueio da apoptose. Nosso estudo indica que o colágeno V participa da perpetuação da fibrose pulmonar por mecanismos IL-17 dependente e independentes, indicando o potencial alvo terapêutico do colágeno V e das vias de sinalização da resposta IL-17 no tratamento das doenças fibroproliferativas pulmonares
Pulmonary fibrosis is the pathologic basis for a variety of incurable human chronic lung diseases. IL-17A, a glycoprotein secreted from IL-17– producing cells, has recently been shown to be a profibrotic cytokine involved in type V collagen synthesis and pulmonary fibrosis. Remodeling of the extracellular matrix by collagen I and V, cell death and Th-17 immune response were evaluated in Balb/c, wild and IL-17 receptor A knockout C57/B6J mice, to determine the pathways that prolong the late phase of the fibrotic process induced by bleomycin and paraquat. Electron microscopy, immunofluorescence, immunohistochemistry, in situ detection of apoptosis, morphometry, tridimensional reconstruction and a real-time PCR were used to evaluate the amount, structure and molecular chains of collagen types, apoptosis and immune cells. We verified increased synthesis and secretion of type V collagen that promoted the maintenance of pulmonary fibrosis in a IL-17A dependent manner. However, we observed that the critical Th17 markers, IL-17, STAT3, TGF-β, IL-6, IL-21, IL-23 and CD4+ T cells, were significantly increased in the fibrosis-susceptible strain and intensified in the absence of IL-17 receptor A. Increased Th17 markers resulted in an increase in CD4+ T cells in fibrotic lung tissue toward an immune response that effectively blocked degradation of collagen V, which contributes to block apoptosis. Our studies indicate that collagen V participates in the maintenance of pulmonary fibrosis in both Th-17 – dependent and -independent manners and that collagen V and the components of the Th-17 signaling pathway are potential therapeutic targets for the treatment of fibroproliferative lung diseases
Pulmonary fibrosis is the pathologic basis for a variety of incurable human chronic lung diseases. IL-17A, a glycoprotein secreted from IL-17– producing cells, has recently been shown to be a profibrotic cytokine involved in type V collagen synthesis and pulmonary fibrosis. Remodeling of the extracellular matrix by collagen I and V, cell death and Th-17 immune response were evaluated in Balb/c, wild and IL-17 receptor A knockout C57/B6J mice, to determine the pathways that prolong the late phase of the fibrotic process induced by bleomycin and paraquat. Electron microscopy, immunofluorescence, immunohistochemistry, in situ detection of apoptosis, morphometry, tridimensional reconstruction and a real-time PCR were used to evaluate the amount, structure and molecular chains of collagen types, apoptosis and immune cells. We verified increased synthesis and secretion of type V collagen that promoted the maintenance of pulmonary fibrosis in a IL-17A dependent manner. However, we observed that the critical Th17 markers, IL-17, STAT3, TGF-β, IL-6, IL-21, IL-23 and CD4+ T cells, were significantly increased in the fibrosis-susceptible strain and intensified in the absence of IL-17 receptor A. Increased Th17 markers resulted in an increase in CD4+ T cells in fibrotic lung tissue toward an immune response that effectively blocked degradation of collagen V, which contributes to block apoptosis. Our studies indicate that collagen V participates in the maintenance of pulmonary fibrosis in both Th-17 – dependent and -independent manners and that collagen V and the components of the Th-17 signaling pathway are potential therapeutic targets for the treatment of fibroproliferative lung diseases
Descrição
Palavras-chave
Fibrose pulmonar, Citocinas, Matriz extracelular, Imuno-histoquímica, Colageno, Pulmonary fibrosis
Como citar
FABRO, Alexandre Todorovic. Remodelamento parenquimatoso pulmonar em dois modelos experimentais de fibrose. 2012. 100 f. Tese (doutorado) - Universidade Estadual Paulista Julio de Mesquita Filho, Faculdade de Medicina Veterinaria e Zootecnia, 2012.