Colonic Engyodontium fungus triggers neutrophil antimicrobial activity to suppress Lactobacillus johnsonii–derived glutamic acid–maintained Tregs
Xinying Wang, Haiyang Sun, Ying Tan, Shaoting Xu, Zishan Liu, Kaile Ji, Ding Qiu, Jianping Deng, Bingbing Feng, Xueting Wu, Yoichiro Iwakura, Minhu Chen, Rui Feng, Chanyan Huang, Ce Tang
Xinying Wang, Haiyang Sun, Ying Tan, Shaoting Xu, Zishan Liu, Kaile Ji, Ding Qiu, Jianping Deng, Bingbing Feng, Xueting Wu, Yoichiro Iwakura, Minhu Chen, Rui Feng, Chanyan Huang, Ce Tang
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Research Article Gastroenterology Microbiology

Colonic Engyodontium fungus triggers neutrophil antimicrobial activity to suppress Lactobacillus johnsonii–derived glutamic acid–maintained Tregs

Abstract

Isolating commensal fungi from mouse intestines has been challenging, limiting our understanding of their role in intestinal immune homeostasis and diseases. Using an Fc fusion protein of the C-type lectin receptor Dectin-2, we successfully purified the commensal Ascomycota fungus Engyodontium sp. from mouse feces. Engyodontium enhances the antimicrobial activity of colonic neutrophils via the CARD9 pathway and exacerbates colitis by impairing the colonization of intestinal Lactobacillus johnsonii WXY strain. L. johnsonii produces high levels of l-glutamic acid by expressing the glutaminase-encoding gene glsA to facilitate Treg expansion via enhancing IL-2 receptor signaling. Patients with Crohn disease (CD) and ulcerative colitis harbored increased Engyodontium and decreased L. johnsonii abundance. Engyodontium directly induced calprotectin in human colonic neutrophils, and patients with CD had lower levels of l-glutamic acid, which also promoted human Treg expansion. These findings highlight the Engyodontium-calprotectin axis against the Lactobacillus-glutamate-Treg cascade to aggravate colitis, suggesting commensal Engyodontium-triggered signaling as a therapeutic target for mucosal inflammatory diseases.

Authors

Xinying Wang, Haiyang Sun, Ying Tan, Shaoting Xu, Zishan Liu, Kaile Ji, Ding Qiu, Jianping Deng, Bingbing Feng, Xueting Wu, Yoichiro Iwakura, Minhu Chen, Rui Feng, Chanyan Huang, Ce Tang

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Figure 5

Attenuation of fungus-promoted colitis in Dectin-2–deficient mice is dependent on commensal microbiota.

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Attenuation of fungus-promoted colitis in Dectin-2–deficient mice is dep...
(A–F) WT and Clec4n–/– mice were separated or co-housed for 4 weeks and subsequently treated with DSS while maintained in housing conditions. (A) Body weight loss and (B) DAI. (C) Gross colon morphology and length measurements at sacrifice on day 9. (D) Representative H&E-stained distal colon sections. (E) Frequencies of cLP neutrophils and Treg cells measured by flow cytometry. (F) Heatmap of immune-related gene expression in colon tissues assessed by qPCR (A–C, n = 9/co-housed group, WT separated n = 14, Clec4n–/– separated n = 10; D, n = 6/group; E, n = 6/co-housed group, WT separated n = 10, Clec4n–/– separated n = 7; F, n = 4/group). (G–I) WT and Card9–/– mice were co-housed for 4 weeks and treated with DSS. DAI (G), histological analysis (H), and colon gene expression profiles (I) (G, n = 7/group; I, n = 4/group; H, n = 5/group). (J–N) Antibiotic-pretreated WT mice received fecal microbiota transplants from WT (WT f), Clec4n–/– (Clec4n–/– f), or Card9–/– (Card9–/– f) donor mice followed by DSS treatment. Body weight loss (J), DAI (K), gross colon morphology and length (L), distal colon histology (M), and cLP neutrophil and Treg frequencies (N) (J–L, and N, WT f, n = 9; Clec4n–/– f, n = 10; Card9–/– f, n = 10; M, n = 5/group). (O–S) 16S rDNA-Seq analysis of fecal microbiota from WT and Clec4n–/– mice under physiological conditions, showing phylum-level composition (O), β diversity by PCoA (P), family-level abundance (Q), abundance of selected taxa (R), and detectable lactic acid bacteria species (S) (n = 4/group). (T) DAI in WT and Clec4n–/– mice treated with DSS with or without vancomycin (Vanco) (WT, n = 6; Clec4n–/–, n = 8; Clec4n–/– Vanco, n = 8). Data in A–C, and G are pooled from 3 independent experiments, and data in D, E, J–L, N, and T are pooled from 2 independent experiments. Data in F and I are from 1 of 2 independent experiments. Data in A–E, G, H, J–L, R, and T are presented as mean ± SD. Statistical analysis: 1-way ANOVA with Bonferroni’s multiple-comparison test (A, B, J, K, T), 1-way ANOVA with Tukey’s multiple-comparison test (C–E and L–N), 2-tailed unpaired Student’s t test (F, H, and Q), and 2-way ANOVA test with repeated measures (G).