Diabetes, Vol 42, Issue 12 1815-1822, Copyright © 1993 by American Diabetes Association
The effect of glucose on proteoglycans produced by cultured mesangial cells
S Silbiger, D Schlondorff, S Crowley, L Rosenberg, H Choi, V Hatcher and P Gordon
Department of Medicine, Montefiore Medical Center, Bronx, NY 10467.
Altered proteoglycan metabolism may play a role in the development of
diabetic glomerulopathy. This study was conducted to examine the effects of
glucose on the production and physical characteristics of proteoglycans
generated by rat mesangial cells in culture. Rat mesangial cells were
exposed to elevated glucose media (500 mg/dl) or standard glucose media
(200 mg/dl) for 8-10 days, and proteoglycan synthesis was determined using
35S-labeling in conjunction with anion exchange and sizing chromatography.
Rat mesangial cells generated predominantly chondroitin/dermatan sulfate
proteoglycans, with small amounts of heparan sulfate proteoglycans. High
glucose did not alter the number of rat mesangial cells after 24 h or after
8-10 days, compared with cells grown under standard glucose conditions. The
total amount of glycosaminoglycan generated and the sizes of the major
proteoglycans were not different between cultures grown in standard and
elevated glucose medium. Levels of mRNA for the proteoglycan, biglycan (as
assessed by Northern blot analysis), also were comparable between the
standard and elevated glucose conditions. Exposure to media high in glucose
did not change the rate of secretion of proteoglycans from the cell layer
to the medium, but did result in a greater quantity of radiolabeled
proteoglycan deposited in the extracellular matrix. The cell, extracellular
matrix and medium proteoglycans isolated from the elevated glucose
cultures, consistently eluted from the anion exchange column at a lower
[NaCl] compared with those generated under standard glucose conditions,
indicating a loss of anionic charges.(ABSTRACT TRUNCATED AT 250 WORDS)