Dietary Chitin Particles Called Mimetic Fungi Ameliorate Colitis in Toll-Like Receptor 2/CD14- and Sex-Dependent Manners

Abstract

Chitin is a natural N-acetylglucosamine polymer and a major structural component of fungal cell walls. Dietary chitin is mucoadhesive; anti-inflammatory effects of chitin microparticles (CMPs; 1- to 10-μm diameters) have been demonstrated in models of inflammatory bowel disease (IBD). The goals of this study were to assess (i) whether CMPs among various chitin preparations are the most effective against colitis in male and female mice and (ii) whether host chitin-binding Toll-like receptor 2 (TLR2) and CD14 are required for the anti-inflammatory effect of chitin. We found that colitis in male mice was ameliorated by CMPs and large chitin beads (LCBs; 40 to 70 μm) but not by chitosan (deacetylated chitin) microparticles, oligosaccharide chitin, or glucosamine. In fact, LCBs were more effective than CMPs. In female colitis, on the other hand, CMPs and LCBs were equally and highly effective. Neither sex of TLR2-deficient mice showed anti-inflammatory effects when treated with LCBs. No anti-inflammatory effect of LCBs was seen in either CD14-deficient males or females. Furthermore, an in vitro study indicated that when LCBs and CMPs were digested with stomach acidic mammalian chitinase (AMC), their size-dependent macrophage activations were modified, at least in part, suggesting reduced particle sizes of dietary chitin in the stomach. Interestingly, stomach AMC activity was greater in males than females. Our results indicated that dietary LCBs were the most effective preparation for treating colitis in both sexes; these anti-inflammatory effects of LCBs were dependent on host TLR2 and CD14.

How Gut Bacterial Dysbiosis Can Promote Candida albicans Overgrowth during Colonic Inflammation

“…Additionally, oral administration of chitin in the DSS-induced colitis model reduced the number of aerobic bacteria and proliferation of C. glabrata , and decreased the impact of colitis mediated by the expression of TLR-8, dectin-1 and PPARγ and anti-inflammatory mediators ( Figure 6 ) [ 71 ]. These observations are consistent with recent experimental studies, which showed that the anti-inflammatory effects of chitin are dependent on both TLR-2 and CD14 in the DSS-induced colitis model [ 88 ].…”

Biological Analyses-Derived Translational Findings in the T Cell Receptor Alpha Chain Knockout Mouse as an Experimental Model for Ulcerative Colitis

“…Furthermore, Louis et al reported that an intermediate size of chitin particles showed an anti-inflammatory effect after being digested with acidic mammalian chitinases depending on the expression of host TLR2 and CD14 [137]. Clinically, chitin microparticles are well tolerated in healthy volunteers and show a more enhanced anti-inflammatory effect after nasal lipopolysaccharide challenges as compared to the placebo group [138]. Based on the positive effect of chitin microparticles, they may also have a potentially useful therapeutic effect on IBD as well.…”

Chitin extraction from crab shells by two-step fermentation with Lacticanttacllus pantarum and Pseudomonas aeruginosa

“…Chitin is the second most abundant natural organic compound after cellulose, the only alkaline polysaccharide and the most abundant nitrogenous organic compound in nature. Chitin and its derivatives (CDs), chitosan, chitooligosaccharides etc., have been proved anti-inflammatory (Azuma et al 2015;Louis et al 2019), antioxidant and antibacterial (Park et al 2010;Luan et al 2022;Aouadi et al 2023), together with the properties of biocompatibility and biodegradability, which makes CDs a kind of environmental-friendly materials, showing a broad range of applications in the present and future. The most promising application areas of CDs is medical and pharmaceutical industry.…”