Proinflammatory cytokine interferon-γ and microbiome-derived metabolites dictate epigenetic switch between forkhead box protein 3 isoforms in coeliac disease

Abstract

SummaryCoeliac disease (CD) is an autoimmune enteropathy triggered by gluten and characterized by a strong T helper type 1 (Th1)/Th17 immune response in the small intestine. Regulatory T cells (T reg ) are CD4 1 CD25 11 forkhead box protein 3 ( FoxP3 1 ) cells that regulate the immune response. Conversely to its counterpart, FoxP3 full length (FL), the alternatively spliced isoform FoxP3 D2, cannot properly down-regulate the Th17-driven immune response. As the active state of CD has been associated with impairments in T reg cell function, we aimed at determining whether imbalances between FoxP3 isoforms may be associated with the disease. Intestinal biopsies from patients with active CD showed increased expression of FOXP3 D2 isoform over FL, while both isoforms were expressed similarly in non-coeliac control subjects (HC). Conversely to what we saw in the intestine, peripheral blood mononuclear cells (PBMC) from HC subjects did not show the same balance between isoforms. We therefore hypothesized that the intestinal microenvironment may play a role in modulating alternative splicing. The proinflammatory intestinal microenvironment of active patients has been reported to be enriched in butyrate-producing bacteria, while high concentrations of lactate have been shown to characterize the preclinical stage of the disease. We show that the combination of interferon (IFN)-g and butyrate triggers the balance between FoxP3 isoforms in HC subjects, while the same does not occur in CD patients. Furthermore, we report that lactate increases both isoforms in CD patients. Collectively, these findings highlight the importance of the ratio between FoxP3 isoforms in CD and, for the first time, associate the alternative splicing process mechanistically with microbial-derived metabolites.

Thymosin β4 cytoplasmic/nuclear translocation as a new marker of cellular stress. A Caco2 case study

“…26 Butyrate, a short chain fatty acid produced by commensal bacteria of the human intestine, was already used to induce oxidative stress and apoptosis in CaCo2 cell cultures in Fauser et al 27 Moreover, it was reported that butyrate could act as an epigenetic "switch" of the immune system. 28 Butyric acid has been in fact associated with the ability to inhibit histone deacetylases (HDAC), and favors a state of acetylated histones in the cell. 29 DMSO is a powerful oxidant that is oen used as a solvent in various experimental tests and in NMR analysis, while its signals have low interferences, and it can dissolve a large number of substances.…”

Translational Chemistry Meets Gluten‐Related Disorders

“…show that regulatory T cells from CD patients are impaired in their ability to suppress the proliferation of CD4 + CD25 − responder cells after CD3/CD28 co‐stimulation in comparison to regulatory T cells from healthy individuals (Figure c). In their study, Serena et al . demonstrate overexpression of the alternatively spliced isoform of FoxP3 in CD mucosa.…”

Cross-Talk Between Gluten, Intestinal Microbiota and Intestinal Mucosa in Celiac Disease: Recent Advances and Basis of Autoimmunity

“…Studies thus suggest the imperative interaction of intestinal bacteria with immune system to direct the differentiation of both pro-inflammatory and anti-inflammatory T cell populations ( Round and Mazmanian, 2009 ). The role of Regulatory T cells (Treg) has become clearer with the efforts of Serena et al (2017) that help us to understand the pathogenic role of gut microbiota and their metabolites in CD through epigenetic processes. Treg cells are subset of CD4 T cells responsible for maintaining immune response to foreign antigens ( Lehtimäki and Lahesmaa, 2013 ).…”

“…Ex-vivo cultures of intestinal biopsies treated with butyrate trigger a balance between FoxP3 isoforms in HC subjects, while the same does not occur in CD patients. That shows the role of microbial metabolites in modulation of splicing, thus triggering to an inflammatory state with some role in pathogenesis of CD ( Serena et al, 2017 ).…”

“…To the best of knowledge in the current literature, there is not a single report related to small intestinal butyrate levels of CD vs. controls. Serena et al (2017) have co-related their small intestinal biopsy based concept with fecal metabolome based reported studies that looked a little controversial toward development of their hypothesis. Microbial derived metabolite in feces is not a reflection of those from small intestine because microbial communities and microbial derived metabolites differ in different parts of gut ( Gorham et al, 2017 ).…”