title: Convergent and divergent development among M cell lineages in mouse mucosal epithelium.
abstract: M cells are specialized epithelial cells mediating immune surveillance of the mucosal lumen by transepithelial delivery of Ags to underlying dendritic cells (DC). At least three M cell phenotypes are known in the airways and intestine, but their developmental relationships are unclear. We used reporter transgenic mouse strains to follow the constitutive development of M cell subsets and their acute induction by cholera toxin (CT). M cells overlying intestinal Peyer's patches (PPs), isolated lymphoid follicles, and nasal-associated lymphoid tissue are induced by distinct settings, yet show convergent phenotypes, such as expression of a peptidoglycan recognition protein-S (PGRP-S) transgene reporter. By contrast, though PP, isolated lymphoid follicle, and villous M cells are all derived from intestinal crypt stem cells, their phenotypes were clearly distinct; for example, PP M cells frequently appeared to form M cell-DC functional units, whereas villous M cells did not consistently engage underlying DC. B lymphocytes are critical to M cell function by forming a basolateral pocket and possible signaling through CD137; however, initial commitment to all M cell lineages is B lymphocyte and CD137 independent. CT causes induction of new M cells in the airway and intestine without cell division, suggesting transdifferentiation from mature epithelial cells. In contrast with intestinal PP M cells, CT-induced nasal-associated lymphoid tissue M cells appear to be generated from ciliated Foxj1(+)PGRP-S(+) cells, indicative of a possible precommitted progenitor. In summary, constitutive and inducible differentiation of M cells is toward strictly defined context-dependent phenotypes, suggesting specialized roles in surveillance of mucosal Ags.
authors: Division of Biomedical Sciences, University of California Riverside, Riverside, CA 92521, USA.
authors: Jing
authors: J
authors: Wang
authors: Veronica
authors: V
authors: Gusti
authors: Andrea
authors: A
authors: Saraswati
authors: David D
authors: DD
authors: Lo
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics; D019070:Cell Lineage / Q000235:genetics / Q000276:immunology; D055879:Gene Knock-In Techniques; D017930:Genes, Reporter / Q000276:immunology; D007413:Intestinal Mucosa / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D057507:Mice, 129 Strain; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009297:Nasal Mucosa / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000276:immunology
chemical_list: D002352:Carrier Proteins; C118897:peptidoglycan recognition protein