Objective and design: In the present study, the effect of a synthetic peptide (H(92)-G(102)) identical to the C-terminus of murine S100A9 (mS100A9p) was investigated on adherent peritoneal cell function.
Materials and methods: For in vitro assays, peritoneal cells were obtained from the abdominal cavity of mice and incubated, with the different concentrations of mS100A9p, for 1 h, and then their spreading and phagocytosis activities were evaluated. For ex-vivo assays, cells obtained from animals treated for 1 h with the peptide were submitted to the mannose-receptor phagocytosis assay. Shorter homologue peptides to the C-terminus of mS100A9p were also evaluated on in vitro phagocytosis assays of Candida albicans particles.
Results: mS100A9p reduced both the spreading index and phagocytic activity, in vitro and ex-vivo, independent of the receptor evaluated. The homologue peptide corresponding to the H(92)-E(97) region of mS100A9p, the zinc-binding motif, was responsible for such an effect.
Conclusion: These results suggest a modulator effect of the C-terminus of S100A9 protein on the function of adherent peritoneal cells.