Diabetes, Vol 40, Issue 5 540-547, Copyright © 1991 by American Diabetes Association
Effects of nonenzymatic glycosylation of mesangial matrix on proliferation of mesangial cells
ST Crowley, M Brownlee, D Edelstein, JA Satriano, T Mori, PC Singhal and DO Schlondorff
Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461.
Cross-linking of cell matrix components by nonenzymatic glycosylation may
contribute to diabetic glomerulopathy. We examined the effects of
modification of matrix by nonenzymatic glycosylation on mesangial cell
function. Matrix was generated by growing mesangial cells in tissue culture
for 2 wk and removing the cells with a detergent cell-lysis solution. By
indirect immunofluorescence and Northern-blot analysis, the remaining
matrix contained laminin, fibronectin, and collagens type I and IV. The
matrix was modified by incubation for 24 h with 50 mM glycolaldehyde, a
highly reactive cross-linking nonenzymatic glycosylation product, or for 2
wk with 200 mM glucose-6-phosphate (G6P). Modification was carried out with
or without equimolar aminoguanidine, an inhibitor of cross-link formation.
Nonenzymatic glycosylation of the matrix by glycolaldehyde or G6P was
confirmed by fluorometry and [14C]G6P incorporation and was prevented by
aminoguanidine. [3H]thymidine incorporation for 24 h by mesangial cells
plated onto unmodified or modified matrix was then performed. Modification
of matrix had no effect on attachment of mesangial cells, determined 4 h
after plating. Nonenzymatic glycosylation of matrix by glycolaldehyde or
G6P significantly inhibited thymidine incorporation by mesangial cells.
This effect was partially reversible by aminoguanidine.
Aminoguanidine-modified matrix had no effect on thymidine incorporation.
Thymidine-incorporation results were confirmed by direct cell counting. We
conclude that modification of matrix by nonenzymatic glycosylation
influences growth of mesangial cells, which could contribute to the
mesangial abnormalities of diabetic glomerulopathy.