RESUMO
Granulocyte-macrophage colony-stimulating factor plays an important role in the activation of microglia in the central nervous system. We have recently shown (see text) that granulocyte-macrophage colony-stimulating factor activates the proliferation and subsequent migration of microglia from organotypic cortex brain slices. The aim of this study was to investigate whether this activation is modulated by different putative intracellular pathway inhibitors. Our data show that the protein kinase C inhibitor staurosporine enhanced the proliferation as well as the differentiation of slice-derived microglia, while the phosphoinositol-3-kinase inhibitor LY294002 markedly suppressed the proliferative activity. In conclusion, proliferation, migration, as well as differentiation of rat microglia are highly regulated by intracellular signaling cascades.
Assuntos
Microglia/citologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteína Quinase C/metabolismo , Animais , Antígeno CD11b/análise , Diferenciação Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Córtex Cerebral/química , Córtex Cerebral/citologia , Córtex Cerebral/efeitos dos fármacos , Cromonas/farmacologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Imuno-Histoquímica , Macrófagos/imunologia , Microglia/química , Microglia/efeitos dos fármacos , Monócitos/imunologia , Morfolinas/farmacologia , Técnicas de Cultura de Órgãos , Inibidores de Fosfoinositídeo-3 Quinase , Proteína Quinase C/antagonistas & inibidores , Ratos , Transdução de Sinais/efeitos dos fármacos , Estaurosporina/farmacologiaAssuntos
Encéfalo/enzimologia , Dopamina beta-Hidroxilase/genética , Estimulação Magnética Transcraniana , Tirosina 3-Mono-Oxigenase/genética , Animais , Estimulação Elétrica , Regulação Enzimológica da Expressão Gênica , Hibridização In Situ , Masculino , RNA Mensageiro/análise , Ratos , Ratos Sprague-DawleyRESUMO
Microglial activation and proliferation occur in nearly all forms of brain injury. The aim of this study was to investigate the influence of glial cell-line derived neurotrophic factor (GDNF) on proliferation and/or survival in a GMIR1 rat microglial cell line, which proliferates in response to granulocyte-macrophage-colony stimulating factor (GM-CSF). Endogenous GDNF and its receptor, GFRalpha-1, were detected in GMIR1 cells by ELISA and immunohistochemistry/Western blot, respectively. Recombinant GDNF strongly enhanced GMIR1 cell numbers and BrdU-incorporation, an effect inhibited by GDNF blocking antibodies. Inhibition of cAMP/cGMP dependent protein kinase enhanced the GDNF-induced GMIR1 cell number. The results suggest that GDNF has synergistic survival promoting effects on microglia potentially via autocrine mechanisms.
Assuntos
Fator Estimulador de Colônias de Granulócitos e Macrófagos/fisiologia , Microglia/metabolismo , Fatores de Crescimento Neural/fisiologia , Animais , Western Blotting , Contagem de Células , Linhagem Celular Transformada/efeitos dos fármacos , Linhagem Celular Transformada/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Ensaio de Imunoadsorção Enzimática , Fator Neurotrófico Derivado de Linhagem de Célula Glial , Imuno-Histoquímica , L-Lactato Desidrogenase/metabolismo , Microglia/citologia , Microglia/efeitos dos fármacos , Fatores de Crescimento Neural/farmacologia , Nitritos/análise , Nitritos/metabolismo , Ratos , Proteínas Recombinantes/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Coloração e RotulagemRESUMO
Cytokines play an important role in the regulation of proliferation and migration in the central nervous system. The aim of this study was to determine if granulocyte macrophage-colony stimulating factor (GM-CSF) activates cells in the cortex of organotypic brain slice cultures. Our data show that murine GM-CSF markedly stimulated the proliferation and migration of small round microglia from a cortex slice. These round cells were strongly positive for integrin CD11b (OX-42), isolectin B4-lectin-binding, the monocytic marker ED1 and partly expressed major histocompatibility complex (MHC) class II antigen (OX-6). Only some differentiated microglia were visible which expressed the integrin CD11c and MHCII. GM-CSF enhanced the proliferation as analyzed by bromodeoxyuridine incorporation. The number of migrated cells decreased during culturing and enhanced terminal dUTP nick-end labelling positive nuclei were found. Taken together, our data conclude that GM-CSF is an important cytokine, which regulates the proliferation and migration of cortical microglia.