Distinct microRNA expression profiles in follicle-associated epithelium and villous epithelium

M cells in follicle-associated epithelium (FAE) covering intestinal lymphoid follicles serve as a portal of entry for particulate antigens (Kanaya and Ohno, 2014 [1]). Despite their biological significance, molecular mechanisms that govern M-cell differentiation and function have not been fully elucidated. MicroRNAs (miRNAs) have a role to control host gene expression profiles that modulate cellular physiology and characteristic. Many studies have shown that miRNAs regulate diverse biological processes including developmental timing, differentiation and growth control of cells and tissues (Ivey and Srivastava, 2010 [2]). miRNAs are also relevant to differentiation and function of intestinal epithelium (McKenna et al., 2010 [3]; Runtsch et al., 2014 [4]). Expression profiles and functions of miRNAs in the intestinal epithelium have been examined in jejunal and colonic mucosa [3]. In contrast, those in FAE remain uncharacterized. To address this deficiency, we isolated Peyer's Patch (PP) FAE and villous epithelium (VE) surrounding the FAE, and compared the miRNA expression profiles of FAE and VE by microarray analysis. This revealed that 43 miRNAs were up-regulated, whereas 9 miRNAs were down-regulated, in FAE compared to VE. A unique pattern of miRNA expression by FAE may reflect important diversity in cellular phenotypes and/or functional features of FAE. All microarray data has been deposited at GEO under accession number GSE46264.