Pigment epithelium-derived factor inhibits erythropoietin-induced retinal endothelial cell angiogenesis by suppression of PI3K/Akt pathway.

Abstract

Erythropoietin (EPO) plays a critical role in the vascular system and exhibits angiogenic activity in endothelial cells (ECs) such as stimulation of cell proliferation, migration and tube formation in vitro. EPO is the major regulator of cell proliferation and differentiation of erythroid precursors and there by preventing the apoptosis. Pigment epithelial derived factor (PEDF) is a potent anti-angiogenic factor whose effects are partially mediated through the induction of EC apoptosis. The mechanism of EPO and PEDF in retinal neovascularization has not been well documented yet. The effect of EPO and PEDF on cell proliferation was determined by MTT assay. In vitro wound-scratch assay was performed to study the migration of ECs and in vitro tube formation was assessed by the on-gel assay system using gelatin. Inhibitor assay was carried out using LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor. Further, PI3K/Akt activity was assessed by transient transfection assay using constitutively active (CA) and dominant negative (DN) Akt mutants. Dextran permeability assay was performed to determine the vascular permeability. We report that EPO stimulates EC proliferation, migration, tube formation and permeability whereas PEDF inhibits the EPO-induced ECs proliferation and permeability. Over expression of DN Akt blocked EPO stimulation of proliferation and permeability, while over expression of CA Akt rescues the inhibitory effect of PEDF on proliferation and permeability. These results demonstrate that PEDF may inhibit the EPO-induced proliferation and permeability via PI3K/Akt-dependent pathway.

• Authors: Ravinarayanan Haribalaganesh, Sardarpasha Sheikpranbabu, Elayappan Banumathi, Sangiliyandi Gurunathan
• Journal: Experimental eye research (Exp Eye Res) Vol. 90 Issue 6 Pg. 726-33 (Jun 2010) ISSN: 1096-0007 [Electronic] England
• PMID: 20298690 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Retracted Publication)
• Copyright: Copyright 2010 Elsevier Ltd. All rights reserved.

Chemical References

• Angiogenesis Inhibitors
• Chromones
• Dextrans
• Enzyme Inhibitors
• Eye Proteins
• Morpholines
• Nerve Growth Factors
• Phosphoinositide-3 Kinase Inhibitors
• Serpins
• pigment epithelium-derived factor
• Erythropoietin
• 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
• Proto-Oncogene Proteins c-akt

Topics

• Angiogenesis Inhibitors (pharmacology)
• Animals
• Capillary Permeability (drug effects)
• Cell Culture Techniques
• Cell Movement (drug effects)
• Cell Proliferation (drug effects)
• Chromones (pharmacology)
• Dextrans (metabolism)
• Dose-Response Relationship, Drug
• Endothelium, Vascular (drug effects)
• Enzyme Inhibitors (pharmacology)
• Enzyme-Linked Immunosorbent Assay
• Erythropoietin (antagonists & inhibitors, pharmacology)
• Eye Proteins (pharmacology)
• Goats
• Morpholines (pharmacology)
• Nerve Growth Factors (pharmacology)
• Phosphatidylinositol 3-Kinases (metabolism)
• Phosphoinositide-3 Kinase Inhibitors
• Proto-Oncogene Proteins c-akt (antagonists & inhibitors, metabolism)
• Retinal Neovascularization (metabolism, prevention & control)
• Retinal Vessels (cytology)
• Serpins (pharmacology)
• Transfection