Effects of oxidative modifications induced by the glycation of bovine serum albumin on its structure and on cultured adipose cells.
Non-enzymatic glycosylation (glycation) and oxidative damages represent major research areas insofar as such modifications of proteins are frequently observed in numerous states of disease. Albumin undergoes structural and functional alterations, caused by increased glycosylation during non insulin-dependent diabetes mellitus, which is closely linked with the early occurrence of vascular complications. In this work, we first characterized structural modifications induced by the glycation of bovine serum albumin (BSA). A pathophysiological effect of glycated BSA was identified in primary cultures of human adipocytes as it induces an accumulation of oxidatively modified proteins in these cells. BSA was incubated in the presence or absence of physiological, pathological or supra-physiological concentrations of glucose at 37 degrees C for 7 weeks. Enhanced BSA glycation percentages were determined using boronate affinity columns. The occurrence of oxidative modifications was found to be enhanced in glycated BSA, after determination of the free thiol groups content, electrophoretic migration and infrared spectrometry spectra. An accumulation of carbonyl-modified proteins and an increased release of isoprostane were observed in cell media following the exposure of adipocytes to glycated albumin. These results provide a new possible mechanism for enhanced oxidative damages in diabetes.
Chesne
Serge
S
Laboratoire de Biochimie et Génétique Moléculaire (LBGM), Université de La Réunion, 15, Avenue René Cassin, BP 7151, 97715 Saint-Denis-Messag cedex 09, La Réunion, France.
Rondeau
Philippe
P
Armenta
Sergio
S
Bourdon
Emmanuel
E
D017667:Adipocytes / Q000378:metabolism*; D002478:Cells, Cultured; D006031:Glycosylation; D006801:Humans; D028421:Isoprostanes / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013438:Sulfhydryl Compounds / Q000378:metabolism
D028421:Isoprostanes; D013438:Sulfhydryl Compounds; D012710:Serum Albumin, Bovine