RESUMO
Idiopathic Pulmonary Fibrosis (IPF) is a progressive disorder that is marked by an over accumulation of activated fibroblast populations. Despite the improved understanding of many mechanisms within this disease, global gene expression analysis has few focused studies on the fibroblast, the central effector cell of progressive fibrosis. We present a unique analysis of IPF pulmonary fibroblasts as they transition through cell culture and identify in vitro altered cellular processes. Fibroblasts were isolated from diseased (n = 8) and non-diseased (n = 4) lungs. Global gene expression analysis was carried out at the initial point of isolation and after 3 weeks of culture. We identify several genes that are altered by removal of the fibroblast from the IPF environment. Comparison of this subset of genes to four previously published whole lung analyses refined our list to a small subset of key fibroblast specific genes important in IPF. Application of STRING database analysis and confirmation via in-vitro and histological assay highlights the CXCL14/CXCR4 chemokine axis with a possible role in the progression and/or activation of fibroblasts within the IPF lung. Our findings, present a possible therapeutic target for IPF and a model for the study and discovery of novel protein and processes in this terrible disease.
Assuntos
Quimiocinas CXC/genética , Fibroblastos/patologia , Fibrose Pulmonar Idiopática/genética , Receptores CXCR4/genética , Transcriptoma , Quimiocina CXCL12/análise , Quimiocina CXCL12/genética , Quimiocinas CXC/análise , Progressão da Doença , Feminino , Fibroblastos/metabolismo , Redes Reguladoras de Genes , Humanos , Fibrose Pulmonar Idiopática/patologia , Masculino , Receptores CXCR4/análiseRESUMO
Activated fibroblasts are the central effector cells of the progressive fibrotic process in idiopathic pulmonary fibrosis (IPF). Characterizing the genomic phenotype of isolated fibroblasts is essential to understanding IPF pathogenesis. Comparing the genomic phenotype of non-cultured pulmonary fibroblasts from advanced IPF patients' and normal lungs revealed novel genes, biological processes and concomitant pathways previously unreported in IPF fibroblasts. We demonstrate altered expression in proteasomal constituents, ubiquitination-mediators, Wnt, apoptosis and vitamin metabolic pathways and cell cycle regulators, suggestive of loss of cellular homeostasis. Specifically, FBXO32, CXCL14, BDKRB1 and NMNAT1 were up-regulated, while RARA and CDKN2D were down-regulated. Paradoxically, pro-apoptotic inducers TNFSF10, BAX and CASP6 were also found to be increased. This comprehensive description of altered gene expression in isolated IPF fibroblasts underscores the complex biological processes characteristic of IPF and may provide a foundation for future research into this devastating disease.
Assuntos
Fibroblastos/metabolismo , Regulação da Expressão Gênica/fisiologia , Fibrose Pulmonar Idiopática/genética , Fibrose Pulmonar Idiopática/fisiopatologia , Pulmão/citologia , Fenótipo , Transdução de Sinais/fisiologia , Apoptose/genética , Western Blotting , Ciclo Celular/genética , Quimiocinas/metabolismo , Citocinas/metabolismo , Perfilação da Expressão Gênica , Genômica , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Imatinib mesylate is a small molecule inhibitor that selectively inhibits the PDGF receptor kinase as well the cKIT and Abl kinases, among other targets. Various studies have implicated the PDGF pathway in the pathogenesis of pulmonary arterial hypertension (PAH). Inhibition with imatinib mesylate has shown efficacy in human case reports and experimental models of PAH. Results from a Phase II trial of imatinib mesylate in PAH did not meet the primary end point but showed improvement in several secondary end points and in a subgroup analysis. As suggested by this study as well as a few case reports, imatinib may be effective in a subset of patients with more severe disease. However, this remains to be further validated through a Phase III study, which is already underway. In conclusion, it appears that imatinib mesylate may hold promise as an adjunct drug in PAH therapy, especially since it is directed at a pathway not previously targeted.
Assuntos
Anti-Hipertensivos/uso terapêutico , Hipertensão Pulmonar/tratamento farmacológico , Piperazinas/uso terapêutico , Inibidores de Proteínas Quinases/uso terapêutico , Pirimidinas/uso terapêutico , Anti-Hipertensivos/farmacocinética , Anti-Hipertensivos/farmacologia , Benzamidas , Humanos , Mesilato de Imatinib , Pulmão/efeitos dos fármacos , Piperazinas/farmacocinética , Piperazinas/farmacologia , Inibidores de Proteínas Quinases/farmacocinética , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/farmacocinética , Pirimidinas/farmacologia , Receptores do Fator de Crescimento Derivado de Plaquetas/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Vasodilatação/efeitos dos fármacosRESUMO
Pulmonary fibrosis is a disease characterized by progressive scarring of the lungs, with idiopathic pulmonary fibrosis (IPF) being the most aggressive form. The diagnosis of IPF is made after other conditions are excluded and is based on a characteristic clinical presentation, radiographic features and, sometimes, pathologic specimen. Existing IPF drug regimens, including corticosteroids and cytotoxic medications, are generally ineffective. To date, only lung transplantation has been shown to improve mortality in carefully selected patients. Multiple therapeutic agents have been investigated but none have proven to be successful. Novel drugs are constantly being sought in an attempt to find a therapy that halts or reverses this disease. Imatinib mesylate is used for chronic myelogenous leukemia and gastrointestinal stromal tumors. It also has antifibrotic properties, as demonstrated in several studies using mouse models of pulmonary fibrosis. Currently, trials are underway to investigate its efficacy in human subjects with IPF.
