Up-Regulation of MUC2 Mucin Expression by Serum Amyloid A3 Protein in MouseColonic Epithelial Cells

[摘要] References(32)Serum amyloid A (SAA) proteinsare acute-phase proteins and are classified into multiple isoforms; however, thebiological functions of each SAA isoform are not fully understood. In this study, toclarify the roles of SAA3 in the intestine, we characterized mRNA expression in mousecolonic epithelial CMT-93 cells treated with rotavirus, Toxoplasma,Staphylococcus aureus, and Escherichia coli, as wellas lipopolysaccharide (LPS) and recombinant murine SAAs (rSAAs). E. colitogether with LPS, but not the other pathogens, enhanced SAA3 mRNA expression. The mRNAexpression of SAA3 by dead E. coli was higher than that by livingE. coli, and the mRNA expression by E. coli and LPSincreased in a dose-dependent manner. In contrast, mRNA expressions of SAA1 and/or SAA2were not stimulated by any of the treatments. In comparisons of cell treatments with rSAA1or rSAA3, rSAA3 significantly up-regulated the mRNA expression of mucin 2 (MUC2), a majorcomponent of the mucus layer of the intestines that acts as an epithelial cell barrieragainst pathogens, while MUC2 mRNA expression was not significantly increased byE. coli and LPS. Furthermore, treatment with rSAAs intensively inducedtumor necrosis factor-α mRNA expression. These results suggest that SAA3 plays a role inhost innate immunity in the colon by up-regulating MUC2 mucin production, which builds aphysiological barrier of colonic epithelia against bacterial invasion.

[学科分类] 兽医学

[关键词] colon;MUC2;mucin;SAA3;serum amyloid A