Dysregulation of immune responses to environmental antigens by the intestine leads to the chronic inflammatory disease, inflammatory bowel disease (IBD). Recent studies have thus sought to identify a dietary component that can inhibit lipopolysaccharide (LPS)-induced nuclear factor-kappa beta (NF-κB) signaling to ameliorate IBD. This study assessed if the lactic acid bacteria (LAB) from kimchi, suppresses the expression of tumor necrosis factor-alpha (TNF-α) in peritoneal macrophages induced by LPS. Leuconostoc lactis EJ-1, an isolate from LAB, reduced the expression of interleukin-6 (IL-6) and IL-1β in peritoneal macrophages induced by LPS. The study further tested whether EJ-1 alleviates colitis induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in mice. TNBS significantly increased myeloperoxidase (MPO) expression, macroscopic colitis scores, and colon shortening. Oral administration of L. lactis EJ-1 resulted in an inhibited in TNBS-induced loss in body weight, colon shortening, MPO activity, and NF-κB and inducible nitric oxide synthase expression; it also led to a marked reduction in cyclooxygenase-2 expression. L. lactis EJ-1 also inhibited the TNBS-induced expression of TNF-α, IL-1β, and IL-6; however, it induced the expression of IL-10. The M2 macrophage markers arginase I, IL-10, and CD206 were elevated by EJ-1. Collectively, these results suggest that EJ-1 inhibits the NF-κB signaling and polarizes M1- to M2-macrophage transition, which help in ameliorating colitis.
Keywords: 2,4,6-trinitrobenzene sulfonic acid (TNBS); Leuconostoc lactis; NF-κB; colitis.
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