Contribution of the Gut Microbiota in P28GST-Mediated Anti-Inflammatory Effects: Experimental and Clinical Insights

Abstract

An original immuno-regulatory strategy against inflammatory bowel diseases based on the use of 28 kDa glutathione S-transferase (P28GST), a unique schistosome protein, was recently proposed. Improvement of intestinal inflammation occurs through restoration of the immunological balance between pro-inflammatory T-helper 1 (Th1) responses and both T-helper 2 (Th2) and regulatory responses. However, detailed mechanisms explaining how P28GST prevents colitis and promotes gut homeostasis remain unknown. Considering the complex interplay between the adaptive and innate immune system and the intestinal microbiota, we raised the question of the possible role of the microbial ecosystem in the anti-inflammatory effects mediated by the helminth-derived P28GST protein. We first analyzed, by 16S rRNA sequencing, the bacterial profiles of mice fecal microbiota at several time points of the P28GST-immunomodulation period prior to trinitrobenzene sulfonic acid (TNBS)-colitis. The influence of gut microbiota in the P28GST-mediated anti-inflammatory effects was then assessed by fecal microbiota transplantation experiments from P28GST-immunized mice to either conventional or microbiota depleted naïve recipient mice. Finally, the experimental data were supplemented by the temporal fecal microbiota compositions of P28GST-treated Crohn’s disease patients from a pilot clinical study (NCT02281916). The P28GST administration slightly modulated the diversity and composition of mouse fecal microbiota while it significantly reduced experimental colitis in mice. Fecal microbiota transplantation experiments failed to restore the P28GST-induced anti-inflammatory effects. In Crohn’s disease patients, P28GST also induced slight changes in their overall fecal bacterial composition. Collectively, these results provide key elements in both the anti-inflammatory mechanisms and the safe therapeutic use of immunomodulation with such promising helminth-derived molecules.

Safety of P28GST, a Protein Derived from a Schistosome Helminth Parasite, in Patients with Crohn’s Disease: A Pilot Study (ACROHNEM)

“…In that study, too, after the P28GST treatment, the IgG levels increased; IgE levels increased only slightly, and IgA levels did not increase [7]. Finally, we detected no significant changes in gut microbiota composition, as reported previously [9].…”

“…The P28GST-driven reduction in colonic inflammation was associated with a reduction in the Th1/Th17 inflammatory response, and an increase in the immunoregulatory response involving Th2/Treg cells and M2 macrophages [5,8,9]. Specifically, P28GST combines the antigenic properties and regulatory enzymatic activities of the antioxidant GST with the anti-inflammatory properties of prostaglandin-D-synthase.…”

High‐dose dietary supplementation with zinc prevents gut inflammation: Investigation of the role of metallothioneins and beyond by transcriptomic and metagenomic studies

“…The rarefaction curves for bacterial species as a function of the number of sequences (representing the total bacteria diversity) were similar in the two data sets; whereas the curve's plateau showed that the sequencing was deep enough to cover all microbial representatives ( Figure 6A). The mean number of OTUs per individual (~250) was in line with other studies in mice 51,58 ( Figure 6B). The specific richness of the observed OTUs was similar before and after Zn supplementation.…”

“…The DNA extraction, 16S metagenomic analysis, and bioinformatics analyses were performed according to optimized, standardized methodologies developed by GenoScreen (Lille, France), as described previously. 51 The DNA was extracted from 200 mg of mouse feces. The procedure was based on the use of the QIAamp stool DNA Kit (Qiagen, Courtaboeuf, France) but various preliminary mechanical and chemical lysis steps were added, in order to fully lyse bacteria in general and Gram-positive bacteria in particular.…”

“…gov) using the Ribosomal Database Project classifier method (version 2.2). 51 Finally, a table listing all the OTUs created was generated; it included the number of sequences in each sample related to each OTU and their respective taxonomic affiliations. Alpha diversity indexes (observed OTUs, the Chao1 richness estimator, and the Shannon diversity index) were generated from the OTU table.…”