Identification, distribution, and tissular origin of the α5(IV) and α6(IV) collagen chains in the developing human intestine

✍ Scribed by Aline Simoneau; F. Elizabeth Herring-Gillam; Pierre H. Vachon; Nathalie Perreault; Nuria Basora; Yamina Bouatrouss; Louis-Phillipe Pageot; Jing Zhou; Jean-François Beaulieu

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 474 KB
• Volume: 212
• Category: Article
• ISSN: 1058-8388
• DOI: 10.1002/(sici)1097-0177(199807)212:3<437::aid-aja11>3.0.co;2-y

✦ Synopsis

The basement membrane type IV collagen is a family composed of six genetically distinct but structurally similar polypeptide chains, ␣1-␣6. The ␣1(IV) and ␣2(IV) chains are ubiquitous components of all BMs whereas the other four have a restricted tissue distribution. In the present study, we have analyzed the expression, distribution, and cellular origin of the ␣5(IV) and ␣6(IV) chains in the developing and adult human small intestine and in well-characterized in vitro models by indirect immunofluorescence, Western blot, and RT-PCR. We have found that in the fetal small intestine, ␣5(IV) and ␣6(IV) are present in the epithelial BM and, in contrast to ␣1(IV) and ␣2(IV), are produced by both epithelial and mesenchymal cells. A distinct tissular origin for the ␣1/␣2(IV) and ␣5/␣6(IV) chains suggests that ␣5(IV) and ␣6(IV) associate as a heterotrimer in this organ. We have also found that a particular situation of ␣5(IV)/␣6(IV) chain expression occurs in the adult intestine. Indeed, as compared with the fetal intestine, ␣6(IV) chain production is maintained while the expression of the ␣5(IV) chain is substantially reduced. Altered expression of the ␣5(IV) chain was also observed in the differentiating enterocytic-like Caco-2/15 cells, suggesting that in the intestinal model, the ␣5(IV) chain is subject to a regulated expression. Taken together, these observations indicate that the human intestinal epithelial BM contains up to four type IV collagen chains: the classical ␣1(IV)/␣2(IV) chains, which originate from mesenchymal cells, and the ␣5(IV)/␣6(IV) chains, which are of both epithelial and mesenchymal origin and have their expression regulated throughout development.