Maf is a regulator of differentiation for gut immune epithelial cell Microfold cell (M cell)

Microfold cells (M cells) are a specialized subset of epithelial intestinal cells responsible for immunosurveillance of the gastrointestinal tract. M cells are located in the Peyer’s patches and are crucial for monitoring and the transcytosis of antigens, microorganisms, and pathogens via their mature receptor GP2. A mature M cell with Gp2 receptor aids in the uptake of antigens, which are passed through the single layer of epithelium and presented to underlying antigen-presenting cells and processed further down-stream with B cells, T cells, and dendritic cells. Recent studies revealed several transcription factors and ligands responsible for the development and differentiation of mature M cells however, an exhaustive list of factors remains to be elucidated. Our recent work on the epigenetic regulation of M cell development found 12 critical transcription factors that were controlled by the polycomb recessive complex 2. Musculoaponeurotic fibrosarcoma transcription factor (Maf) was identified as a gene regulated by the polycomb repressive complex (PRC2) during the development of M cells. In this paper, we explore Maf’s critical role in M cell differentiation and maturation. Maf falls under the purview of RANKL signaling, is localized in the Peyer’s patches of the intestine, and is expressed by M cells. Given that, complete knockout of the Maf gene leads to a lethal phenotype, organoids isolated from Maf knockout mice and treated with RANKL exhibited impaired M cell development and a significant decrease in Gp2 expression. These findings reveal that Maf is an important regulator for M cell development and differentiation. ### Competing Interest Statement The authors have declared no competing interest. * M cells : Microfold cells PP : Peyer’s Patch FAE : Follicle associated epithelium VE : villous epithelium RANKL : Receptor activator of nuclear factor kappa B ligand Rank : Receptor activator of nuclear factor kappa B PRC2 : polycomb repressive complex 2 Maf : Musculoaponeurotic fibrosarcoma