Fig. 2: SAA participates in gut barrier.
From: Serum amyloid protein A in inflammatory bowel disease: from bench to bedside
The lipopolysaccharides (LPS) expressed by Gram-negative bacteria induce the SAA3 secretion of epithelial cells. SAA3 binds to toll-like receptor 2 on the surface of neutrophils, promoting their IL-22 secretion, which performs a protective effect on the gut epithelium. SAA1/2 binds to OmpA and its homologs on the surface of Gram-negative bacteria, promotes the phagocytosis of neutrophils and macrophages on these bacteria.
