Fermentable Dietary Fiber Promotes Helminth Infection and Exacerbates Host Inflammatory Responses

Abstract

Fermentable dietary fibers promote the growth of beneficial bacteria, can enhance mucosal barrier integrity, and reduce chronic inflammation. However, effects on intestinal type 2 immune function remain unclear. In this study, we used the murine whipworm Trichuris muris to investigate the effect of the fermentable fiber inulin on host responses to infection regimes that promote distinct Th1 and Th2 responses in C57BL/6 mice. In uninfected mice, dietary inulin stimulated the growth of beneficial bacteria, such as Bifidobacterium (Actinobacteria) and Akkermansia (Verrucomicrobia). Despite this, inulin prevented worm expulsion in normally resistant mice, instead resulting in chronic infection, whereas mice fed an equivalent amount of nonfermentable fiber (cellulose) expelled worms normally. Lack of expulsion in the mice fed inulin was accompanied by a significantly Th1-skewed immune profile characterized by increased T-bet + T cells and IFN-g production in mesenteric lymph nodes, increased expression of Ido1 in the cecum, and a complete absence of mast cell and IgE production. Furthermore, the combination of dietary inulin and high-dose T. muris infection caused marked dysbiosis, with expansion of the Firmicutes and Proteobacteria phyla, near elimination of Bacteroidetes, and marked reductions in cecal short-chain fatty acids. Neutralization of IFN-g during infection abrogated Ido1 expression and was sufficient to restore IgE production and worm expulsion in inulin-fed mice. Our results indicate that, whereas inulin promoted gut health in otherwise healthy mice, during T. muris infection, it exacerbated inflammatory responses and dysbiosis. Thus, the positive effects of fermentable fiber on gut inflammation appear to be context dependent, revealing a novel interaction between diet and infection.

The Prebiotic‐Like Effects of Coprinus comatus Polysaccharides on Gut Microbiota in Normal Mice and Those with Acute Alcoholic Liver Injury: A Comparative Study

“…Hence, we could preliminarily deduce the CCP could adjust the changes of two main phyla to produce prebiotic-like effects [22][23][24]. Verrucomicrobia was considered as a probiotic, which showed a negative correlation with hepatic inflammation and oxidative stress [25,26]. Especially, Akkermansiaceae, the most representative gut microbe in the Verrucomicrobia, could prevent the weight gain caused by a high-fat diet, repair the damaged integrity of the intestinal epithelium barrier, reduce endotoxin levels in the blood, and improve insulin resistance [27,28].…”

The phytonutrient cinnamaldehyde limits intestinal inflammation and enteric parasite infection

“…Mesenteric lymph nodes (MLN) were isolated from mice as described previously [22]. MLN cells were washed and surface stained with anti-TCRβ-FITC (clone H57-597) and anti-CD4-PerCP-Cy5.5 (clone RM4-5).…”

“…RNA was isolated from either cell lysate or jejunal tissue using RNeasy kit or miRNeasy mini kits, respectively, according to manufacturer’s protocols (Qiagen, Denmark). Microarray analysis was carried out on tissue and cell RNA as previously described, utilizing the Affymetrix Clariom S HT-24 pipeline [22]. The data was analysed by Transcriptome Analysis Console software (Thermo Fisher), and Gene set enrichment analysis (GSEA; Broad Institute) was used for pathway analysis.…”

“…DNA was extracted from 100mg of cecal contents using the Bead-Beat Micro AX Gravity kit (A&A Biotechnology, Poland) according to the manufacturer’s instructions with addition of mutanolysin and lysozyme to enhance bacterial cell wall degradation. Amplification of the V3 region of the 16S rRNA gene and sequencing was conducted as previously described [22]. The raw dataset containing pair-ended reads was merged and trimmed, and zero-radius operational taxonomic units (zOTU) obtained using the Greengenes (13.8) 16S rRNA gene collection as a reference database.…”

Garlic-derived organosulfur compounds regulate metabolic and immune pathways in macrophages and attenuate intestinal inflammation in mice

“…muris parasites (strain E) were maintained and T. muris excretory/secretory (E/S) products prepared as described previously. [17] Eggs were purified from the faeces of mice and embryonated for at least two months before being used for infection. Experimental mice were infected with 20 eggs suspended in water by oral gavage.…”