Monokine modulation of human astroglial cell production of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. I. Effects of IL-1 alpha and IL-beta.

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-1 alpha and IL-1 beta 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-1 alpha and IL-1 beta. 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.     

Effects of antioxidant and nitric oxide on chemokine production in TNF-alpha-stimulated human dermal microvascular endothelial cells

Chemokines have been implicated convincingly in the driving of leukocyte emigration in different inflammatory reactions. Multiple signaling mechanisms are reported to be involved in intracellular activation of chemokine expression in vascular endothelial cells by various stimuli. Nevertheless, redox-regulated mechanisms of chemokine expression in human dermal microvascular endothelial cells (HDMEC) remain unclear. This study examined the effects of pyrrolidine dithiocarbamate (PDTC, 0.1 mM) and spermine NONOate (Sper-NO, 1 mM) on the secretion and gene expression of chemokines, interleukin (IL)-8, monocyte chemotactic protein (MCP)-1, regulated upon activation normal T cell expressed and secreted (RANTES), and eotaxin. This study also addresses PDTC and Sper-NO effects on activation of nuclear factor kappa B (NF-kappaB) induced by TNF-alpha (10 ng/ml). Treatment with TNF-alpha for 8 h significantly increased secretion of IL-8, MCP-1, and RANTES, but not of eotaxin, in cultured HDMEC. Up-regulation of these chemokines was suppressed significantly by pretreatment with PDTC or Sper-NO for 1 h, but not by 1 mM 8-bromo-cyclic GMP. The mRNA accumulation of IL-8, MCP-1, RANTES, and eotaxin, and activation of NF-kappaB were induced by TNF-alpha for 2 h; all were suppressed significantly by the above two pretreatments. These findings indicate that both secretion and mRNA accumulation of IL-8, MCP-1, and RANTES in HDMEC induced by TNF-alpha are inhibited significantly by pretreatment with PDTC or Sper-NO, possibly via blocking redox-regulated NF-kappaB activation. These results suggest that restoration of the redox balance using antioxidant agents or nitric oxide pathway modulators may offer new opportunities for therapeutic interventions in inflammatory skin diseases.