Salmonella enterica serovar Typhimurium chitinases modulate the intestinal glycome and promote small intestinal invasion

Abstract

Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the leading causes of food-borne illnesses worldwide. To colonize the gastrointestinal tract, S. Typhimurium produces multiple virulence factors that facilitate cellular invasion. Chitinases have been recently emerging as virulence factors for various pathogenic bacterial species, and the S. Typhimurium genome contains two annotated chitinases: STM0018 (chiA) and STM0233. However, the role of these chitinases during S. Typhimurium pathogenesis is unknown. The putative chitinase STM0233 has not been studied previously, and only limited data exists on ChiA. Chitinases typically hydrolyze chitin polymers, which are absent in vertebrates. However, chiA expression was detected in infection models and purified ChiA cleaved carbohydrate subunits present on mammalian surface glycoproteins, indicating a role during pathogenesis. Here, we demonstrate that expression of chiA and STM0233 is upregulated in the mouse gut and that both chitinases facilitate epithelial cell adhesion and invasion. S. Typhimurium lacking both chitinases showed a 70% reduction in invasion of small intestinal epithelial cells in vitro. In a gastroenteritis mouse model, chitinase-deficient S. Typhimurium strains were also significantly attenuated in the invasion of small intestinal tissue. This reduced invasion resulted in significantly delayed S. Typhimurium dissemination to the spleen and the liver, but chitinases were not required for systemic survival. The invasion defect of the chitinase-deficient strain was rescued by the presence of wild-type S. Typhimurium, suggesting that chitinases are secreted. By analyzing N-linked glycans of small intestinal cells, we identified specific N-acetylglucosamine-containing glycans as potential extracellular targets of S. Typhimurium chitinases. This analysis also revealed a differential abundance of Lewis X/A-containing glycans that is likely a result of host cell modulation due to the detection of S. Typhimurium chitinases. Similar glycomic changes elicited by chitinase deficient strains indicate functional redundancy of the chitinases. Overall, our results demonstrate that S. Typhimurium chitinases contribute to intestinal adhesion and invasion through modulation of the host glycome.

Sodium Humate-Derived Gut Microbiota Ameliorates Intestinal Dysfunction Induced by Salmonella Typhimurium in Mice

“…Typhimurium-caused intestinal damage, as evidenced by the reduced colon shortening and colon and ileum histological damage. In agreement with the previous study ( 24 ), we confirmed that the administration of HNa decreased the proinflammatory cytokines such as myeloperoxidase (MPO), interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and interleukin-2 (IL-2) in both the serum and colon of S . Typhimurium-infected mice.…”

“…Typhimurium is one of the main causes of foodborne illnesses worldwide ( 23 ). The antibacterial property of HNa has been widely reported ( 24 ). However, the antibacterial effect of HNa on S .…”

Exploring roles of the chitinase ChiC in modulating Pseudomonas aeruginosa virulence phenotypes

“…Enzymes within the GH18 family are primarily recognized for their roles in chitin depolymerization but have also been reported to hydrolyze fragments of peptidoglycan, Nod-factors, LacdiNAc, glycans from IgG and IgA, carbohydrates present on mammalian glycoproteins, and mucin extracts, illustrating the functional diversity of these enzymes ( 18 , 66 – 74 ). In the context of chitin metabolism, PA is unable to grow on chitin particles ( 11 ), exhibits delayed growth on GlcNAc ( Fig.…”

“…Additionally, it is noteworthy that other GH18 family enzymes have been shown to have activity toward non-chitin substrates, such as ChiA from S. Typhimurium and L. monocytogenes (which cleaves LacdiNAc, a disaccharide motif common in mucins), ChiA from L. pneumophila (associated with mucin hydrolysis), and a recent study showing ChiA of S . Typhimurium (altering the N- glycome profile of gut epithelial cells) ( 18 , 66 , 67 ) (the structures of ChiC and these enzymes are shown in Fig. 8 ).…”

Diet outperforms microbial transplant to drive microbiome recovery post-antibiotics

“…Real-time qPCR was performed using iTaq Universal SYBR Green Supermix with CFX384 Real-Time System (Bio-Rad). Primers and cycling conditions were derived from Devlin et al, 2022 55 (Table S10).…”