Hydrogen peroxide enhances LPS-induced nitric oxide production via the expression of interferon beta in BV-2 microglial cells.

Activated microglia produces inflammatory cytokines and nitric oxide (NO) that involved in neuronal injury and neurodegenerative diseases. We report herein, that H(2)O(2) intensifies the LPS-triggered expression of iNOS in the microglia cell line, BV-2, resulting in an enhancement in the production of NO. The NO production induced by a combination of LPS and H(2)O(2) was blocked by the addition of an anti-interferonβ (IFNβ) neutral antibody, suggesting that IFNβ levels are correlated with the LPS/H(2)O(2)-induced production of NO. However, although the expression of IFNβ was induced by H(2)O(2) treatment alone, neither the expression of iNOS mRNA nor the production of NO were induced. In addition, the expression of IFN receptor (IFNR) was induced by LPS but not by H(2)O(2). These data indicate that although H(2)O(2) alone cannot induce iNOS expression because of the insufficient expression of IFNR, in the presence of LPS, H(2)O(2) enhances iNOS expression via the expression of IFNβ. Our findings suggest that H(2)O(2) produced by activated microglia further enhances NO production in various inflammatory states.