title: Thiol regulation of vascular endothelial growth factor-A and its receptors in human retinal pigment epithelial cells.
abstract: 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.
authors.affiliation: 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.
authors.forename: Parameswaran G
authors.initials: PG
authors.lastname: Sreekumar
authors.forename: Ram
authors.initials: R
authors.lastname: Kannan
authors.forename: Aruni T
authors.initials: AT
authors.lastname: de Silva
authors.forename: Richard
authors.initials: R
authors.lastname: Burton
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Ryan
authors.forename: David R
authors.initials: DR
authors.lastname: Hinton
mesh_terms: 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*
chemical_list: 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