Multifiber dietary mixture ameliorates Crohn's-like colitis by promoting Treg differentiation via ETS1/RUNX1/Foxp3 axis
Background
Crohn's disease (CD) is a chronic inflammatory disorder driven by immune dysregulation, where the body's immune system attacks the gastrointestinal tract. A key component of mucosal tolerance, regulatory T cells (Tregs), often exhibit dysfunction in CD, directly contributing to its pathogenesis. Current treatments often involve immunosuppressants with significant side effects. Understanding the intricate links between gut microbiota, epigenetics, and immune cell function, particularly Treg homeostasis, offers promising avenues for novel, less invasive interventions like dietary approaches to restore immune balance.
Study Design
Researchers evaluated the therapeutic effects of a special multifiber mixture (MF) on colitis in interleukin-10-/- mice, a well-established model for Crohn's-like disease. The study analyzed various parameters, including T cell phenotypes using flow cytometry, transcriptional profiles via RNA sequencing, gut microbiota composition through metagenomics, and N6-methyl adenosine (m6A) RNA methylation using methylated RNA immunoprecipitation-quantitative polymerase chain reaction (MeRIP-qPCR). The control arm consisted of mice not receiving the MF, allowing for direct comparison of inflammatory markers and immune cell populations.
Results
MF feeding significantly reduced intestinal inflammation and restored epithelial barrier function in the IL-10-/- mouse model. It also promoted Treg differentiation while suppressing Th1/Th17 polarization, indicating a shift towards an anti-inflammatory immune profile. Integrated transcriptomic and proteomic analyses identified ETS1 as a negative regulator of Treg differentiation. This regulation was found to be modulated by gut microbiota-derived S-adenosylmethionine (SAM) through methyltransferase-like protein 3 (METTL3)-mediated m6A methylation. MF feeding reduced SAM levels and m6A enrichment on ETS1 messenger RNA, leading to decreased ETS1 expression. Silencing of ETS1 enhanced Foxp3 expression and expanded the Treg population, confirming its role. RUNX1 was identified as a functional interactor of ETS1, with reciprocal expression patterns validated in both mouse models and colonic tissues from patients with CD.
Key Findings
- Multifiber mixture (MF) significantly reduced intestinal inflammation and restored epithelial barrier function in IL-10-/- mice.
- MF promoted Treg differentiation and suppressed Th1/Th17 polarization, shifting immune balance.
- ETS1 was identified as a negative regulator of Treg differentiation, modulated by gut microbiota-derived SAM.
- MF reduced SAM levels and m6A enrichment on ETS1 mRNA, leading to decreased ETS1 expression.
- Silencing ETS1 enhanced Foxp3 expression and expanded the Treg population, confirming its regulatory role.
Why It Matters
This study provides a strong mechanistic basis for how dietary interventions, specifically a multifiber mixture, can modulate the immune system in Crohn's disease. The findings highlight a novel microbiota-epigenetics-immunity axis, where gut microbiota-derived metabolites like SAM influence m6A methylation and ETS1 expression, ultimately impacting Treg differentiation. This suggests that nutritional strategies could be developed to restore Treg homeostasis, offering a non-pharmacological approach to manage CD. While currently preclinical, this research points towards designing specific fiber-rich diets or supplements that target this pathway, potentially leading to more personalized and effective protocols for patients.
crohns-disease
colitis
dietary-fiber
gut-microbiota
treg
epigenetics