Effect of hyperglycemic condition on proteoglycan secretion in cultured human endothelial cells.
BACKGROUND
Proteoglycans (PGs) are important constituents of the plasma membrane and of the basement membrane supporting the endothelial cell layer. Changes in the amounts or the structures of PGs in the endothelium may affect important functions such as turnover of lipoproteins, filtration properties, and regulation of chemokines during inflammation, which are all relevant in diabetes.


OBJECTIVE
The purpose of this study was to investigate if hyperglycemic conditions would affect the biosynthesis and secretion of PGs in cultured primary human endothelial cells.


METHODS
Primary human umbilical cord vein endothelial cells were established and cultured in vitro. The cells were cultured either in medium with low glucose (LG) (1 g/l) or high glucose (HG) (4.5 g/l). From day 3-4 cells were labeled with (35)S-sulfate for 24 h. (35)S-Labeled macromolecules (medium) were purified by gel chromatography, and isolated macromolecules were analyzed by gel chromatography after different types of treatment, electrophoresis, and immunoprecipitation.


RESULTS
Lower levels of secreted PGs were found in human endothelial cells exposed to HG. The major part of the PGs released was of the heparan sulfate (HS) type, and immunoprecipitation experiments showed that one such PG was syndecan-1. However, there was no difference in the ratio between HS and chondroitin sulfate (CS) under the different experimental conditions. Further, the PGs expressed neither differ with regard to molecular size of the glycosaminoglycan (GAG) chains, nor were their polyanionic properties affected by the different experimental conditions.


CONCLUSIONS
The results obtained suggest that treatment of primary human endothelial cells with hyperglycemia leads to a decrease in PG secretion in primary cultures of human endothelial cells.
Gharagozlian
Sedegheh
S
Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Box 1046, Blindern, 0316 Oslo, Norway. sedegheg@medisin.uio.no
Borrebaek
Jørgen
J
Henriksen
Tore
T
Omsland
Tone Kristin
TK
Shegarfi
Hamid
H
Kolset
Svein Olav
SO
D001485:Basement Membrane / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002850:Chromatography, Gel; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D042783:Endothelial Cells / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology*; D006801:Humans; D006943:Hyperglycemia / Q000378:metabolism / Q000503:physiopathology; D047468:Immunoprecipitation; D008970:Molecular Weight; D011509:Proteoglycans / Q000378:metabolism*; D013462:Sulfur Radioisotopes; D014470:Umbilical Cord / Q000166:cytology
D011509:Proteoglycans; D013462:Sulfur Radioisotopes; D005947:Glucose