RESUMO
Dendritic cells (DC) represent professional antigen-presenting cells that develop from hematopoietic progenitors through successive steps of differentiation. Employing DNA microarray technology, we analysed the specific changes in gene expression that occur when human progenitor cells differentiate into DC. CD34 progenitor cells were first amplified in vitro with stem cell factor (SCF), Flt3 ligand (FL), thrombopoietin and IL-6/soluble IL-6 receptor fusion protein, and cells were then induced to differentiate into DC with IL-4 and GM-CSF. DC maturation was induced by TNFalpha. Progenitor cells and DC were subjected to transcriptional profiling by DNA microarrays that represent 13000 human genes. Our analysis revealed specific changes in the expression of a large number of cell surface antigens including molecules involved in antigen uptake and processing, cell migration and antigen presentation. Genes encoding such molecules were upregulated during DC differentiation as were genes encoding cytokines, cytokine receptors, chemokines and chemokine receptors. Stem cell genes and genes related to the multilineage differentiation potential and proliferative state of progenitor cells were downregulated. Our analysis also provides information on the expression profiles of transcriptional regulators such as the NF-kappaB/rel and STAT transcription factors. Interestingly, NF-kappaB/rel factors were found to be expressed in both progenitor cells and DC at similar levels and were induced by TNFalpha. In contrast, expression of STAT factors increased during DC differentiation and their expression was virtually unaffected by TNFalpha.
Assuntos
Diferenciação Celular/genética , Células Dendríticas/metabolismo , Perfilação da Expressão Gênica , Antígenos CD/análise , Antígenos CD34/análise , Diferenciação Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Divisão Celular/genética , Células Cultivadas , Quimiocinas/genética , Citocinas/genética , Proteínas de Ligação a DNA/genética , Células Dendríticas/citologia , Células Dendríticas/efeitos dos fármacos , Citometria de Fluxo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/efeitos dos fármacos , Células-Tronco Hematopoéticas/imunologia , Humanos , Interleucina-4/farmacologia , NF-kappa B/genética , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Receptores de Quimiocinas/genética , Receptores de Citocinas/genética , Transativadores/genética , Transcrição Gênica , Fator de Necrose Tumoral alfa/farmacologiaRESUMO
Dendritic cells (DCs) are potent antigen-presenting cells with a pivotal role in antigen-specific immune responses. Here, we found that the helix-loop-helix transcription factor Id2 is up-regulated during DC development in vitro and crucial for the development of distinct DC subsets in vivo. Id2-/- mice lack Langerhans cells (LCs), the cutaneous contingent of DCs, and the splenic CD8alpha+ DC subset is markedly reduced. Mice deficient for transforming growth factor (TGF)-beta also lack LCs, and we demonstrate here that, in DCs, TGF-beta induces Id2 expression. We also show that Id2 represses B cell genes in DCs. These findings reveal a TGF-beta-Id2 signaling pathway in DCs and suggest a mechanism by which Id2 affects the lineage choice of B cell and DC progenitors.
Assuntos
Proteínas de Ligação a DNA/genética , Células Dendríticas/metabolismo , Proteínas Repressoras , Fatores de Transcrição/genética , Linfócitos B/metabolismo , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/metabolismo , Células Dendríticas/imunologia , Perfilação da Expressão Gênica , Humanos , Proteína 2 Inibidora de Diferenciação , Análise de Sequência com Séries de Oligonucleotídeos , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/metabolismo , Receptores de Interleucina-4/metabolismo , Fatores de Transcrição/biossíntese , Fatores de Transcrição/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Regulação para CimaRESUMO
Dendritic cells (DC) are professional antigen-presenting cells that possess both migratory properties and potent T cell stimulatory activity, and that allow the uptake of antigenic material inperipheral tissues and its subsequent presentation in the T cell areas of lymphoid organs. Thus motility represents a central property that is required for DC function. Here we report on the expression of the receptor tyrosine kinase c-met in DC. c-Met is the high affinity receptor for scatter factor (SF)/hepatocyte growth factor, and ligand-activated c-met exhibits mitogenic, morphogenic andmotogenic activity in vivo and in vitro. c-Met is signaling competent in DC since it is effectively tyrosine phosphorylated in response to SF ligand. It is demonstrated here that ligand-activated c-met regulates DC adhesion to the extracellular matrix component laminin but leaves antigen presenting function unaffected. Importantly, in ear sheet explant experiments activationof c-met by ligand induces emigration of cutaneous DC (Langerhans cell, LC) from skin, but SF is not a chemoattractant factor for DC. Our results suggest an important role of the c-met/SF system in DC/LC migration.
