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Molecular regulation of vascular endothelial growth factor expression in the retinal pigment epithelium

PURPOSE: Vascular endothelial growth factor (VEGF) plays an important role in homeostasis and diseases of the retinal pigment epithelium (RPE), choriocapillaris, and, most notably, age-related macular degeneration (AMD). Although much is known about VEGF regulation in pathologies, little is known ab...

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Autores principales: Ford, Knatokie M., D’Amore, Patricia A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Molecular Vision 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3298425/
https://www.ncbi.nlm.nih.gov/pubmed/22419845
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author Ford, Knatokie M.
D’Amore, Patricia A.
author_facet Ford, Knatokie M.
D’Amore, Patricia A.
author_sort Ford, Knatokie M.
collection PubMed
description PURPOSE: Vascular endothelial growth factor (VEGF) plays an important role in homeostasis and diseases of the retinal pigment epithelium (RPE), choriocapillaris, and, most notably, age-related macular degeneration (AMD). Although much is known about VEGF regulation in pathologies, little is known about the control of VEGF expression under normal conditions. VEGF expression has been previously shown to be regulated in coordination with cell differentiation in the muscle and kidney. We therefore tested the hypothesis that VEGF in the adult RPE would similarly be regulated in conjunction with differentiation. METHODS: A human retinal pigment epithelium cell line (ARPE-19), a line of immortalized human RPE cells, was used for all experiments. RPE cells were polarized in culture for 4 weeks on laminin-coated Transwells. Levels of VEGF mRNA and protein were determined with real-time PCR and enzyme-linked immunosorbent assay, respectively. VEGF-luciferase reporter constructs were used to identify regions of the VEGF promoter that control VEGF expression in the RPE. Microphthalmia-associated transcription factor (MITF)-Tfe transcription factors were blocked using either a pan MITF-Tfe dominant negative or specific small interfering RNA (siRNA). RESULTS: VEGF mRNA and protein secretion increased over time in the RPE cells cultured on Transwells, with protein secretion occurring in a polarized fashion primarily toward the basolateral side. Overexpression of a dominant negative that targets the MITF-Tfe family resulted in a 50% reduction in VEGF expression. The role of the MITF-Tfe family in VEGF regulation in the RPE was corroborated in studies with the VEGF-luciferase reporter constructs, where deletion of the distal VEGF promoter region containing putative binding sites for the MITF-Tfe family resulted in a 50% reduction in VEGF promoter activity. siRNA knockdown of the MITF-Tfe family individually, and in combination, revealed that downregulation of Tfe3 resulted in reduced VEGF expression. CONCLUSIONS: Our results indicate that Tfe3, in conjunction with other MITF-Tfe members, regulates VEGF expression in the RPE and are consistent with the hypothesis that VEGF expression in RPE cells is regulated as part of their differentiation.
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spelling pubmed-32984252012-03-14 Molecular regulation of vascular endothelial growth factor expression in the retinal pigment epithelium Ford, Knatokie M. D’Amore, Patricia A. Mol Vis Research Article PURPOSE: Vascular endothelial growth factor (VEGF) plays an important role in homeostasis and diseases of the retinal pigment epithelium (RPE), choriocapillaris, and, most notably, age-related macular degeneration (AMD). Although much is known about VEGF regulation in pathologies, little is known about the control of VEGF expression under normal conditions. VEGF expression has been previously shown to be regulated in coordination with cell differentiation in the muscle and kidney. We therefore tested the hypothesis that VEGF in the adult RPE would similarly be regulated in conjunction with differentiation. METHODS: A human retinal pigment epithelium cell line (ARPE-19), a line of immortalized human RPE cells, was used for all experiments. RPE cells were polarized in culture for 4 weeks on laminin-coated Transwells. Levels of VEGF mRNA and protein were determined with real-time PCR and enzyme-linked immunosorbent assay, respectively. VEGF-luciferase reporter constructs were used to identify regions of the VEGF promoter that control VEGF expression in the RPE. Microphthalmia-associated transcription factor (MITF)-Tfe transcription factors were blocked using either a pan MITF-Tfe dominant negative or specific small interfering RNA (siRNA). RESULTS: VEGF mRNA and protein secretion increased over time in the RPE cells cultured on Transwells, with protein secretion occurring in a polarized fashion primarily toward the basolateral side. Overexpression of a dominant negative that targets the MITF-Tfe family resulted in a 50% reduction in VEGF expression. The role of the MITF-Tfe family in VEGF regulation in the RPE was corroborated in studies with the VEGF-luciferase reporter constructs, where deletion of the distal VEGF promoter region containing putative binding sites for the MITF-Tfe family resulted in a 50% reduction in VEGF promoter activity. siRNA knockdown of the MITF-Tfe family individually, and in combination, revealed that downregulation of Tfe3 resulted in reduced VEGF expression. CONCLUSIONS: Our results indicate that Tfe3, in conjunction with other MITF-Tfe members, regulates VEGF expression in the RPE and are consistent with the hypothesis that VEGF expression in RPE cells is regulated as part of their differentiation. Molecular Vision 2012-03-01 /pmc/articles/PMC3298425/ /pubmed/22419845 Text en Copyright © 2012 Molecular Vision. http://creativecommons.org/licenses/by/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Ford, Knatokie M.
D’Amore, Patricia A.
Molecular regulation of vascular endothelial growth factor expression in the retinal pigment epithelium
title Molecular regulation of vascular endothelial growth factor expression in the retinal pigment epithelium
title_full Molecular regulation of vascular endothelial growth factor expression in the retinal pigment epithelium
title_fullStr Molecular regulation of vascular endothelial growth factor expression in the retinal pigment epithelium
title_full_unstemmed Molecular regulation of vascular endothelial growth factor expression in the retinal pigment epithelium
title_short Molecular regulation of vascular endothelial growth factor expression in the retinal pigment epithelium
title_sort molecular regulation of vascular endothelial growth factor expression in the retinal pigment epithelium
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3298425/
https://www.ncbi.nlm.nih.gov/pubmed/22419845
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