Monokine modulation of human astroglial cell production of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor: I. Effects of IL-1α and IL-β

Granulocyte (G)-CSF and granulocyte-macrophage (GM)-CSF enhance phagocyte survival and function and are produced by fibroblasts and endothelial cells after induction by inflammatory mediators such as IL-1. Our ability to detect G-CSF and GM-CSF activity in the conditioned medium of the human astroglial tumor cell line, U87MG, and molecularly clone the cDNA for G-CSF from a U87MG cDNA library raised the possibility that astroglial cells are capable of G-CSF and GM-CSF production within the central nervous system; if so, the production of these CSF by astroglial cells may be inducible by IL-1. We examined the effects of IL-1α and IL-1β on the production of G-CSF and GM-CSF by U87MG and U373MG, another astroglial tumor cell line that does not constitutively produce CSF. We demonstrate that both U87MG and U373MG can be induced to produce G-CSF and GM-CSF by exposure to IL-1α and IL-1β. This response, measured by accumulation of increased CSF mRNA, is rapid, sensitive and due to the enhanced stability of CSF message following IL-1 exposure. The implications of these findings to the immunopathogenesis of central nervous system infections are discussed.