title: The differential distribution of type IV collagen alpha chains in the subepithelial basement membrane of the human alimentary canal.
abstract: We studied distribution patterns of type IV collagen alpha chains in the subepithelial basement membrane (SBM) of the human gastrointestinal tract - the esophagus through the anal canal - by immunofluorescent microscopy using alpha(IV) chain-specific monoclonal antibodies. The alpha1(IV), alpha2(IV), alpha5(IV), and alpha6(IV) chains were found in the SBM throughout the tract, indicating the localization of [alpha1(IV)](2)alpha2(IV) and [alpha5(IV)](2)alpha6(IV) heterotrimeric molecules. The [alpha1(IV)](2)alpha2(IV) molecule was continuously stained, while the [alpha5(IV)](2)alpha6(IV) molecule was weakly stained in gastric glands and small intestinal crypts. In addition, the SBM at the luminal surface epithelium of the stomach and large intestine contained small amounts of alpha3(IV) and alpha4(IV) chains which combined to form the alpha3(IV)alpha4(IV)alpha5(IV) heterotrimeric molecule with alpha5(IV) chain. The SBM beneath the villous epithelium of the small intestine was also demonstrated to have an alpha3(IV) chain and alpha4(IV) chain. Considering the specific locations of the type IV collagen trimers throughout the gastrointestinal SBM, the supramolecular network containing the alpha3(IV)alpha4(IV)alpha5(IV) molecule appears to function as a selective permeability barrier and /or as a protection against chemical stress from the luminal digestive enzymes.
authors.affiliation: Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sato
authors.forename: Ichiro
authors.initials: I
authors.lastname: Naito
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Momota
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Naomoto
authors.forename: Tomoki
authors.initials: T
authors.lastname: Yamatsuji
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Sado
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Ninomiya
authors.forename: Aiji
authors.initials: A
authors.lastname: Ohtsuka
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001485:Basement Membrane / Q000166:cytology / Q000378:metabolism*; D024141:Collagen Type IV / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism*; D005260:Female; D041981:Gastrointestinal Tract / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D051381:Rats
chemical_list: D000911:Antibodies, Monoclonal; D024141:Collagen Type IV