Lipopolysaccharide and lipoteichoic acid enhance serum amyloid A3 mRNAexpression in murine alveolar epithelial cells

摘要

Serum amyloid A (SAA) is an acute-phase protein indicative of inflammation. In murinecolonic epithelial cells, lipopolysaccharide (LPS), a gram-negative bacterial antigen,strongly enhanced mRNA expression of SAA3, but not SAA1 or SAA2, suggesting that SAA3might respond to bacterial infection in other epithelia. We examined SAA1/2 and SAA3 mRNAexpression in murine alveolar epithelial cells exposed to LPS or the gram-positivebacterial antigen, lipoteichoic acid (LTA), using real-time PCR. LPS enhanced SAA3 mRNAexpression at lower concentrations than did LTA, whereas SAA1/2 mRNA expression was notenhanced by either LPS or LTA. These results suggest that SAA3 expression is enhanced inlung epithelium upon bacterial infection as part of innate immunity, with highersensitivity to LPS than to LTA.