Nitric oxide is necessary for CC-class chemokine expression in endotoxin-stimulated ANA-1 murine macrophages

The production of nitric oxide (NO) in response to endotoxin (LPS)-stimulation is associated with a myriad of NO-dependent regulatory functions. The study of NO-dependent genetic programs in the setting of endotoxin stimulation can be aided by determination of genes whose transcription is upregulated in the presence of NO and LPS. Using subtractive suppression hybridization analysis, we demonstrate that ANA-1 murine macrophages produce the CC class chemokines, monocyte chemoattractant protein-1 (JE/MCP-1) and macrophage inflammatory protein-related protein-1 (C10/MRP-1), in response to LPS-mediated nitric oxide (NO) production. MCP-1 and MRP-1 gene transcription and protein synthesis are upregulated in the setting of LPS-induced NO synthesis. NO alone is necessary but insufficient for induction of chemokine protein expression; an additional LPS-dependent signaling pathway is also required. This study suggests a novel mechanism by which NO induces chemokine expression and regulates the host inflammatory response to endotoxin.