Exopolysaccharide-Producing <i>Bifidobacterium adolescentis</i> Strains with Similar Adhesion Property Induce Differential Regulation of Inflammatory Immune Response in Treg/Th17 Axis of DSS-Colitis Mice

• Main Authors: Rui Yu, Fanglei Zuo, Huiqin Ma, Shangwu Chen
• Format: Article
• Language: English
• Published: MDPI AG 2019-04-01
• Series: Nutrients
• Subjects: <i>Bifidobacterium adolescentis</i>; macrophage; Treg/Th17 axis; exopolysaccharide; ERK/p38 MAPK pathway; IBD
• Online Access: https://www.mdpi.com/2072-6643/11/4/782

Intestinal bifidobacteria benefit human health by promoting and modulating the gut flora, and boosting therapeutic efficiency for chronic metabolic diseases and cancer. Recently, <i>Bifidobacterium adolescentis</i> strains with high adhesion to intestinal epithelial cells were associated with induction of T-helper 17 (Th17) cells in humans and rodents. Here, two <i>B. adolescentis</i> strains with similar adhesive ability but different aggregation properties were investigated for specific immunoregulatory effects, including the underlying cellular pathway, on macrophage and T-regulatory (Treg)/Th17 axis activation in vitro and in the colon of dextran sodium sulfate (DSS)-colitis mice in vivo. In-vitro, the auto-aggregative <i>B</i>. <i>adolescentis</i> strain IF1-11 induced significantly higher IL-6 and lower IL-10 secretion from immune cells, and it induced abundant Th17 cells. The non-aggregating strain IF1-03 induced significantly higher IL-10, less IL-6 and a high proportion of Treg/Th17 cells compared to total T cells. In vivo, orally administered IF1-03 protected DSS-colitis mice via activation of dendritic cells or macrophages and skewing of Treg/Th17 cells, consistent with Treg cell induction in vitro. IF1-03 exopolysaccharides showed a functional recognition pattern similar to IF1-03 for IL-10 cytokine secretion and Treg cell-differentiation induction, both dependent on the toll-like receptor 2&#8211;ERK/p38 MAPK-signaling cascade for macrophage activation. We suggest that <i>B</i>. <i>adolescentis</i> exopolysaccharide-associated enterocyte adhesion/aggregation phenotypes determine strain-specific adaptive immune responses in the gut via the macrophage-regulated Treg/Th17 axis.