Volume 119, Issue 3, Pages 734-743 (September 2000) Transient expression of M-cell phenotype by enterocyte-like cells of the follicle- associated epithelium of mouse Peyer's patches  Frédéric Sierro, Eric Pringault, Patricia Simon Assman, Jean–Pierre Kraehenbuhl, Nathalie Debard  Gastroenterology  Volume 119, Issue 3, Pages 734-743 (September 2000) DOI: 10.1053/gast.2000.16481 Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 1 Immunofluorescent localization of (A) SI and (B) E-cadherin in the FAE of a mouse Peyer's patch. Expression of SI is down-regulated in the entire FAE compared with adjacent villous enterocytes. Note the absence of apical epithelial labeling in the area that corresponds to the M-cell compartment. Expression of E-cadherin is lower than that of epithelial cells of adjacent villi (bar = 100 μm). Gastroenterology 2000 119, 734-743DOI: (10.1053/gast.2000.16481) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 2 Immunofluorescent localization of FAE basal lamina components of a Peyer's patch. The labeling pattern of (A) collagen IV and (B) nidogen under the FAE is similar to that seen in the basal lamina along the crypt-villus axis. In contrast, (C) tenascin shows a patchy distribution and (D) perlecan is almost completely absent under the FAE. *Nonspecific coloration of lymphoid cells in the Peyer's patch (bar = 100 μm). Gastroenterology 2000 119, 734-743DOI: (10.1053/gast.2000.16481) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 3 Immunofluorescent detection of laminins in the FAE basal lamina of a Peyer's patch. The labeling pattern in the FAE compared with the villi is similar for (A) β1γ1, (B) α5, and (C) γ2, whereas (D) α2 is asymmetrically distributed in the crypts surrounding the Peyer's patch. On the side in contact with the follicle, α2 labeling is dramatically reduced (bar = 100 μm). Gastroenterology 2000 119, 734-743DOI: (10.1053/gast.2000.16481) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 4 Detection of myofibroblasts under the FAE of Peyer's patches. Myofibroblasts detected with an anti–α-smooth muscle actin monoclonal antibody were present in the crypt lamina propria and lower third of the villi but absent under the FAE and in the lymphoid side of the FAE crypts giving rise to the FAE (bar = 100 μm). Gastroenterology 2000 119, 734-743DOI: (10.1053/gast.2000.16481) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 5 Proliferation, M-cell, and apoptosis compartments in the FAE of mouse Peyer's patches. (A) BrdU labeling of proliferating cells (red) after a 30-minute pulse is restricted to the crypts. (B) Double labeling of M cells (arrowheads) with the UEA-1 lectin (red) and of apoptotic cells (TUNEL) (arrow, green). The FAE is underlined (dashed line). The number of UEA-1–positive cells in the dome's bottom half was found to be 3 times higher than in the dome's apex half (Table 1). Goblet cells (*) are also labeled with the UAE-1 lectin (bar = 100 μm). Gastroenterology 2000 119, 734-743DOI: (10.1053/gast.2000.16481) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 6 Migration kinetics of epithelial cells along the crypt-villus axis and in the FAE. Colocalization of UEA-1–positive cells and migrating BrdU–positive cells. (A–C) Peyer's patches of mice were injected with BrdU for (A) 24, (C) 48, and (B) 55 hours before the mice were killed. (A and B) On sections of Peyer's patches selected for maximum diameter of FAE or (C) on whole mounts, BrdU–positive cells were labeled with a cy3 fluorochrome (red) and UEA-1–positive cells with FITC (green). On sections, the FAE is indicated by a dashed line (bar = 100 μm). (D) The migration of epithelial cells was measured on digitized pictures of BrdU-labeled Peyer's patch sections (apex region) using the NIH-Image software. The distance between the front of the labeled cells and the base of the crypt was measured and converted into micrometers with a graduated scale attached to a cooled charge-coupled device camera (Photonic Science). Each value is the mean of at least 10 measurements. Gastroenterology 2000 119, 734-743DOI: (10.1053/gast.2000.16481) Copyright © 2000 American Gastroenterological Association Terms and Conditions