title: Alpha 1-VIII collagen is expressed in the rat glomerulus and in resident glomerular cells.
abstract: Current knowledge regarding the molecular composition of extracellular matrices in the glomerulus does not explain how these components interact to form stable three-dimensional structures. The recent recognition that short-chain collagens such as type VIII collagen function as molecular bridges in some nonrenal tissues has raised the possibility that such molecules may serve a similar function in the glomerulus. We have recently shown that cultured rat mesangial cells synthesize and secrete several short-chain collagenous proteins, one of which has properties similar to alpha 1-VIII collagen. In the present study we have isolated a rat mesangial cell alpha 1-VIII collagen cDNA clone, the sequence of which is 81% homologous to mouse alpha 1-VIII collagen. We used this cDNA to determine that alpha 1-VIII collagen mRNA is expressed in rat renal cortex and in cultured glomerular mesangial, epithelial, and endothelial cells. Additionally, we demonstrated that alpha 1-VIII collagen is secreted by cultured mesangial cells as an 80-kDa translation product. By immunocytochemistry, alpha 1-VIII collagen localized to the media of large intrarenal arteries and to the capillary loops and the mesangium of normal rat kidney. These results indicate that type VIII collagen is a normal constituent of the rat glomerulus as well as large intrarenal arteries. We speculate that type VIII collagen may function in part to determine the three-dimensional organization of the subendothelial and mesangial matrices.
authors.affiliation: Division of Nephrology, Children's Hospital, Boston, Massachusetts.
authors.forename: N D
authors.initials: ND
authors.lastname: Rosenblum
authors.forename: D M
authors.initials: DM
authors.lastname: Briscoe
authors.forename: M J
authors.initials: MJ
authors.lastname: Karnovsky
authors.forename: B R
authors.initials: BR
authors.lastname: Olsen
mesh_terms: D000818:Animals; D001483:Base Sequence; D003094:Collagen / Q000235:genetics / Q000378:metabolism*; D004727:Endothelium / Q000166:cytology / Q000378:metabolism; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D005260:Female; D005920:Glomerular Mesangium / Q000166:cytology / Q000378:metabolism; D066298:In Vitro Techniques; D007672:Kidney Cortex / Q000378:metabolism; D007678:Kidney Glomerulus / Q000166:cytology / Q000378:metabolism*; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014158:Transcription, Genetic
chemical_list: D012333:RNA, Messenger; D003094:Collagen