Novel dietary polysaccharide SIP promotes intestinal secretory immunoglobulin A secretion in mice under chemotherapy

- SIP is the primary functional compound of squid ink polysaccharides.
- SIP induced higher production of SIgA.
- SIP activates phagocytic cells.
- SIP penetrates epithelial cells via transcellular route.

Chemotherapeutic drugs, such as cyclophosphamide, are one of the most vital means to kill tumors, meanwhile however, inevitable to impair the gastrointestinal (GI) tract. Secretory immunoglobulin A (SIgA) is a keystone anti-inflammatory antibody shielding the intestinal mucosal surfaces by spatially disengaging pathogens and commensals in the gut lumen. In this animal based study, we unraveled that squid ink polysaccharide (SIP) extracted from Ommastrephes bartrami is the predominantly functional polysaccharide featured to promote secretion of intestinal SIgA by increasing the expression of each of its constituents, including IgA, J chain and pIgR. Furthermore, SIP activated phenotypic transformation of monocytes to macrophages, leading to higher expression levels of IL-6, IL-10 and TNF-α, resulting in enhanced syntheses of IgA and J chain in IgA+ cells and that of pIgR in epithelial cells. Our study paves a basis for the implication of the dietary polysaccharide in amelioration of mucosal injuries.

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