HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Ma, W. Articles by Barile, G. R. Search for Related Content PubMed PubMed Citation Articles by Ma, W. Articles by Barile, G. R.

RAGE Ligand Upregulation of VEGF Secretion in ARPE-19 Cells

¹From the Departments of Ophthalmology and ²Surgery, Columbia University College of Physicians and Surgeons, New York, New York.

PURPOSE. The importance of VEGF in stimulating neovascular age-related macular degeneration (AMD) is well-recognized, but the initiating factors that induce local upregulation of VEGF remain unclear. The current study was conducted to test the hypothesis that activation of RAGE (receptor for advanced glycation end products [AGEs]) by its ligands, including AGEs, amyloid-ß peptide (Aß), and S100B/calgranulins, some of which are known components of drusen and Bruch’s membrane deposits, modulate secretion of VEGF by retinal pigment epithelial (RPE) cells.

METHODS. ARPE-19 cells were used for all experiments. The cells were transfected with constructs encoding a signal transduction mutant of human RAGE to assess the RAGE-dependence of intracellular signaling. VEGF secretion and gene expression were assessed by ELISA and quantitative real-time PCR. SDS-PAGE and size exclusion chromatography were performed to analyze the structural changes of S100B after oxidation of its thiol groups under denaturing and nondenaturing conditions, respectively. NF-B activation was assessed via electrophoretic mobility shift assay (EMSA). The impact of the NF-B inhibition was assessed by using parthenolide.

RESULTS. ARPE-19 cells basally secreted VEGF under normal cell culture conditions. Immobilized ligands of RAGE increased VEGF secretion in a RAGE-dependent manner. In contrast, soluble AGE-BSA, fresh Aß, and S100B were less effective in increasing VEGF secretion. Studies with Aß demonstrated that oligomeric and surface-immobilized forms of Aß, but not soluble monomeric forms of Aß, were effective upregulators of VEGF secretion via RAGE. Oxidation of S100B’s thiol groups resulted in the formation of oligomers that displayed distinct RAGE biological activity compared with the simple dimeric form. RAGE-mediated upregulation of VEGF secretion by ARPE-19 cells was largely dependent on NF-B, as indicated by studies with parthenolide.

CONCLUSIONS. Immobilized or oligomerized ligands for RAGE induce RPE cells to increase VEGF secretion. NF-B plays a central role in RAGE-dependent RPE secretion of VEGF. In AMD, activation of the RAGE axis in RPE cells may contribute to upregulation of VEGF, potentially inciting or propagating neovascular macular disease.

This article has been cited by other articles:

				R. Ramasamy, S. F. Yan, and A. M. Schmidt Stopping the Primal RAGE Reaction in Myocardial Infarction: Capturing Adaptive Responses to Heal the Heart? Circulation, June 24, 2008; 117(25): 3165 - 3167. [Full Text] [PDF]

				K. Herold, B. Moser, Y. Chen, S. Zeng, S. F. Yan, R. Ramasamy, J. Emond, R. Clynes, and A. M. Schmidt Receptor for advanced glycation end products (RAGE) in a dash to the rescue: inflammatory signals gone awry in the primal response to stress J. Leukoc. Biol., August 1, 2007; 82(2): 204 - 212. [Abstract] [Full Text] [PDF]