Abstract
Probiotics exhibit beneficial effects on human health. We examined the effect of 59 strains of heat-killed Lactobacillus brevis on their ability to skew Th1/Th2 balance toward Th1 dominant. L. brevis SBC8803 was selected as a potent inhibitor of IgE production. We had previously demonstrated that this strain showed anti-allergic property, prevention of alcoholic liver disease and fortification of intestinal barrier function. In this study, we aimed to isolate the cytoprotective compound from this strain. A culture supernatant of SBC8803 was fractionated by ammonium sulfate precipitation, DEAE anion exchange chromatography, gel filtration, and HPLC, and then targeted components were screened by evaluating cytoprotective HSP27 expression from Caco2/bbe cells. Finally, we identified that the HSP27-inducible fraction was polyphosphate (poly P). Then, poly P was synthesized by polyphosphate kinase. The synthesized poly P significantly suppressed the oxidant-induced intestinal permeability in the mouse small intestine and pharmacological inhibitors of p38 MAPK and integrins counteract its protective effect. Daily intrarectal administration of polyphosphate (10μg) improved the survival rate in 4% sodium dextran sulfate-administered mice. Selection of high poly P producing strain and unravelling the mechanism of its poly P production will lead to therapeutic development to intestinal barrier related various gut disorder.
