Paenibacillus exopolysaccharide repairs GI inflammation by suppressing MAPK and NF-κB and restoring lipid production in Caco-2 cell line

Paenibacillus polymyxa exopolysaccharide PYQ1-EPS is a homogeneous glucomannan-type polysaccharide. In this work, its stability and reparative effects on the in vitro model of inflammatory bowel disease (IBD) and possible mechanisms were investigated to expand its application fields. The results showed that PYQ1-EPS significantly increased the cell viability, inhibited the expression of pro-inflammatory cytokines and promoted the expression of anti-inflammatory cytokines, which effectively blocked the activation of NF-κB and MAPK signaling pathways. Meanwhile, it was found that the anti-inflammatory effect of PYQ1-EPS was closely related to the lipid metabolism of cells, which restored the lipid content of inflammation model cells to 90.7% of the untreated cells. This is the first report that bacterial polysaccharides inhibit gastrointestinal inflammation by modulating lipid metabolism. Upon the understanding of its functional mechanisms, our work demonstrated that PYQ1-EPS has great potential to be developed as a functional food for gastrointestinal protection.