Immuno-regulatory and anti-inflammatory actions of phycocyanin on Caco-2/U937 cells co-culture as a model of the intestinal barrier

Abstract

Background: Phycocyanin, a photosynthetic pigment protein of cyanobacteria Spirulina platensis, has been used as a health or functional food because of its health promoting and medicinal effects such as its antioxidant, anti-inflammatory, immunomodulatory, and anticancer effects.Methods: Under the co-culture system using a human colorectal cancer cell line, Caco-2 cells, and differentiated U937 macrophages in the presence of sodium butyrate (SB) and/or lipopolysaccharide (LPS), immune-regulatory and anti-inflammatory activities of phycocyanin were examined.Results: Phycocyanin attenuated a certain damage in the tight junction of co-cultured Caco-2 cells induced by LPS in the presence of SB, and suppressed IL-6 and IL-8 and conversely enhanced TGF-β1 productions. Phagocytic and bactericidal abilities of the differentiated U937 cells were also regulated under the co-cultivation.Conclusions: Phycocyanin contributes to protecting against inflammation and to regulating macrophages in the mucosal immune responses partly through release of cytokines in the presence of butyrate.Keywords: Spirulina, phycocyanin, Caco-2 cells, U937 cells, IL-6, IL-8, TGF-β1