Thiol regulation of vascular endothelial growth factor-A and its receptors in human retinal pigment epithelial cells.
We investigated the secretion and expression of VEGF-A and its receptors in human retinal pigment epithelial cells (RPE) under conditions of oxidative stress induced by glutathione (GSH) depletion. RPE cells were treated with 500 microM DL-buthionine-(S,R)-sulfoximine (BSO) for varying times up to 24 h. Cellular GSH levels, GSH:GSSG ratios, VEGF-A mRNA and protein expression, as well as VEGF-A secretion, and VEGFR-1 and VEGFR-2 receptor expression were determined. Treatment with BSO caused a significant decrease in intracellular GSH and in GSH/GSSG ratios. Treatment with BSO increased VEGF-A mRNA linearly with time which was significant at 24h (p<0.01 vs untreated controls). An increase was also found for VEGF-A secretion with BSO treatment; incubation of RPE with GSH monoethyl ester (GSH-MEE) caused an 84% decrease in VEGF-A secretion. Further, thiol depletion by BSO caused a significant induction of VEGFR-1 and VEGFR-2. Thus, our studies show that cellular redox status plays an important role in VEGF regulation in RPE cells.
Sreekumar
Parameswaran G
PG
Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033, USA.
Kannan
Ram
R
de Silva
Aruni T
AT
Burton
Richard
R
Ryan
Stephen J
SJ
Hinton
David R
DR
D019328:Buthionine Sulfoximine / Q000494:pharmacology; D005978:Glutathione / Q000494:pharmacology; D006801:Humans; D010857:Pigment Epithelium of Eye / Q000187:drug effects* / Q000378:metabolism; D012160:Retina / Q000166:cytology; D013438:Sulfhydryl Compounds / Q000494:pharmacology*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism*
D013438:Sulfhydryl Compounds; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D019328:Buthionine Sulfoximine; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2; D005978:Glutathione