The murine
S100 protein CP-10 is a potent
chemotactic factor for murine and human myeloid cells in vivo and in vitro. This is the first report describing regulations of the
CP-10 gene by a proinflammatory stimulus,
lipopolysaccharide (LPS), in cells of the monocyte/macrophage lineage. Murine monocyte/macrophage-like WEHI 265 and RAW 264.7 cells preexposed to 5 to 50 ng/mL LPS expressed significant levels of
CP-10 mRNA 4 hours, and maximal at 20 hours, after a secondary LPS challenge. This was accompanied by increasing levels of cell-associated and released
CP-10 protein. In contrast, a single dose of LPS upregulated
CP-10 mRNA in elicited peritoneal macrophages, whereas
mRNA and
protein levels decreased following LPS challenge. The state of macrophage differentiation may control responsiveness as LPS had no effect on
CP-10 basal levels in bone marrow derived macrophages. LPS-induced
CP-10 expression was controlled at the transcriptional level and nuclear run-on and
protein synthesis inhibition assays indicated that LPS priming and challenge of RAW cells occurred via distinct pathways. MRP14, another
S100 protein generally coordinately expressed with human MRP8, was not induced by LPS under the same conditions. We propose that
CP-10 may play a key role in recruitment of leukocytes into tissues in response to
gram-negative bacterial infection.