| Popis: |
Astrocytes are involved in a number of physiological and pathological processes of the CNS, in which cytokines may act both as stimulators and effectors of astrocyte functions. In vitro studies, including those presented here using highly enriched astrocyte cultures from the human embryonic brain, show that macrophage-derived cytokines (interleukin-lb and tumor necrosis factor-a) are very efficient in stimulating the synthesis of a large number of polypeptides displaying pro-inflammatory, anti-inflammatory or neurotrophic activities. The T cell-derived cytokine interferon-g can potentiate the stimulating effects of interleukin-lb and tumor necrosis factor-a on some inflammatory mediators, whereas transforming growth factor-b, a cytokine produced by neural and hematogenous cells, mainly enhances the production of growth factors active on neurons and oligodendrocytes. These in vitro data suggest that cytokines that are transiently expressed in the CNS during development or in pathological conditions can activate distinct functional programs in astrocytes, which may play a specific role in brain growth and in different brain diseases. |
