# Recombinant MAM from Faecalibacterium duncaniae exhibits a protective effect in DNBS-induced colitis

## TL;DR

This study shows that a purified molecule from a gut bacteria can reduce intestinal inflammation in a mouse model, despite being partly denatured during purification.

## Contribution

The first in vitro and in vivo evaluation of purified recombinant MAM's anti-inflammatory effects.

## Key findings

- Recombinant MAM induced an anti-inflammatory cytokine profile in human intestinal and immune cells.
- Oral administration of recombinant MAM reduced colitis symptoms in a mouse model.
- Purified MAM was partly denatured, but still effective in reducing inflammation.

## Abstract

Microbial anti-inflammatory molecule (MAM) is a key effector of the next-generation probiotic Faecalibacterium duncaniae A2-165, a species whose depletion in the gut microbiota is strongly linked to inflammatory bowel disease (IBD) and other conditions. Despite its importance, the direct anti-inflammatory effects of purified MAM have never been evaluated in vitro or in intestinal inflammation models. Prior studies have relied on bacterial supernatants, synthetic peptides, or DNA delivery systems, each with inherent limitations.

In this study, we produced and purified recombinant MAM (R-MAM) under denaturing conditions and, for the first time, demonstrated its direct anti-inflammatory activity in vitro and its protective effects in a colitis murine model. Despite numerous attempts, we were not able to obtain a non-aggregated R-MAM. Therefore, we can assume that the R-MAM used here is partly or totally denatured. Nevertheless, in vitro assays with human intestinal epithelial cells (HT-29) and peripheral blood mononuclear cells (PBMCs) confirmed the ability of MAM to induce an anti-inflammatory cytokine profile. In addition, in a DNBS-induced colitis model, oral administration of R-MAM significantly prevented weight loss and reduced colon weight and thickness, key macroscopic indicators of inflammation.

These findings provide a critical validation step for the therapeutic potential of MAM in intestinal inflammation, despite its purification under denaturing conditions. Future studies should focus on optimizing protein stability and conformational integrity to increase its therapeutic potential as a biotherapeutic agent.

The online version contains supplementary material available at 10.1186/s12934-025-02877-9.