Abstract
Metabolites are thought as the end products in cellular regulatory processes and their levels show the strongest relationships with the phenotype. Previously, we showed that the administration of Clostridium butyricum MIYAIRI 588 (CBM 588) upregulated protectin D1, an anti-inflammatory lipid metabolite, in colon tissue under antibiotic therapy. However, how CBM 588 induces protectin D1 expression and whether the metabolite has anti-inflammatory effects on antibiotic-induced inflammation are unclear. Therefore, here, we evaluated the effect of CBM 588 on lipid metabolism and protectin D1 in gut protection from antibiotic-induced intestinal disorders. In the CBM 588 treatment group, expression levels of genes encoding lipid receptors related to the conversion of DHA to protectin D1, such as polyunsaturated fatty acid (PUFA) receptors, G-protein coupled receptor 120 (GPR120), and 15-lipoxygenase (LOX), were increased in colon tissue. CD4+ cells producing interleukin (IL)-4, the main component of T helper type 2 (Th2) cells that can activate 15-LOX, also increased in CBM 588-treated groups even after clindamycin co-administration. In addition, similar to CBM 588, exogenously administered protectin D1 reduced inflammatory cytokines, while IL-10 and TGF-β1, works as anti-inflammatory cytokines, were increased. Our data revealed that CBM 588 activated 15-LOX to enhance protectin D1 production by increasing IL-4-producing CD4+ cell population in the intestinal tract. Additionally, CBM 588-induced protectin D1 clearly upregulated IL-10-producing CD4+ cells to control antibiotic-induced gut inflammation. We provide new insights into CBM 588-mediated lipid metabolism induction for the treatment of gut inflammatory diseases.