Production of β‐defensin‐2 by human colonic epithelial cells induced by Salmonella enteritidis flagella filament structural protein

Abstract

We recently showed that FliC of Salmonella enteritidis increased human β‐defensin‐2 (hBD‐2) expression, and now describe the signaling responsible pathway. FliC increased the intracellular Ca²⁺ concentration ([Ca²⁺]_in) in Caco‐2 cells. The [Ca²⁺]_in increase induced by FliC was prevented by U73122 and heparin, but not by chelating extracellular Ca²⁺ or pertussis toxin. The FliC‐induced increase in hBD‐2 promoter activity via nuclear factor κB (NF‐κB) was also inhibited by chelation of intracellular Ca²⁺ or by U73122. We conclude that FliC increased [Ca²⁺]_in via inositol 1,4,5‐trisphosphate, which was followed by up‐regulating hBD‐2 mRNA expression via an NF‐κB‐dependent pathway.