S100a4 deficiency is associated with efficient bacterial clearance and protects against joint destruction during staphylococcal infection

Abstract

Background. Efficient host defense mechanisms are crucial for survival in sepsis and septic arthritis. S100 proteins are reported to have proinflammatory and bactericidal properties. The aim of this study was to investigate the role of S100A4 in staphylococcal arthritis. Methods. S100A4 knockout mice (S100A4KO) and wild-type counterparts (WT) were intravenously and intraarticularly challenged with Staphylococcus aureus strain LS-1. Clinical and morphological signs of arthritis and sepsis, phagocytosis, bone mineral density (BMD), and bone metabolism were then monitored in S100A4 and WT mice. Results. S100A4KO mice had a lower bacterial load in the kidneys than WT mice (P < .05) but developed more severe clinical signs of arthritis (P < .05). S100A4 was not bactericidal in vitro. Conclusions. In staphylococcal infection, S100A4 regulates bacterial clearance as well as systemic and local inflammatory responses. © The Author 2011.