Macrophage inflammatory protein 1-alpha mRNA expression in an immortalized microglial cell line and cortical astrocyte cultures.

Macrophage inflammatory protein 1 (MIP-1) is a recently characterized inflammatory and chemokinetic cytokine. Proinflammatory stimuli have been shown to induce expression of MIP-1 by macrophages. We hypothesized that microglia and astrocytes express MIP-1 alpha because of their many immunologic similarities to macrophages. MIP-1 alpha mRNA was examined with quantitative reverse transcription and polymerase chain reaction in an immortalized mouse microglial cell line (BV-2) and in mouse cortical astrocyte cultures. We found that in both the BV-2 microglial cell line and in astrocyte cultures, MIP-1 alpha mRNA was strongly induced by lipopolysaccharide and the phorbol ester PMA. MIP-1 alpha mRNA was reduced by dBcAMP, interferon-gamma, and PGE1. Dexamethasone decreased MIP-1 alpha mRNA levels in astrocyte cultures, but not in BV-2 microglial cells. Interleukin-1 beta, tumor necrosis factor alpha, and MIP-1 alpha had no effect on MIP-1 alpha mRNA expression. These findings demonstrate that MIP-1 alpha mRNA is expressed by cultured glial cells and is regulated by proinflammatory and anti-inflammatory stimuli. MIP-1 alpha may be expressed by microglia and astrocytes in vivo, and may help modulate cerebral inflammation.