Angiopoietin-1 is regulated by miR-204 and contributes to corneal neovascularization in KLEIP-deficient mice.

Abstract

PURPOSE:

Corneal neovascularization can cause loss of vision. The introduction of anti-VEGF therapy has been a major improvement in therapeutic options. Recently, we established Kelch-like Ect2-interacting protein (KLEIP/KLHL20) knockout mice as a model of spontaneous corneal neovascular dystrophy. The aim of the present study was to characterize corneal neovascularization in progressive corneal dystrophy in KLEIP(-/-) mice, to evaluate the efficacy of anti-VEGF therapy, and to identify novel molecular regulators in this experimental model.

METHODS:

Corneal neovascularization was assessed by immunohistochemistry. Vascular endothelial growth factor signaling was inhibited by injection of a blocking antibody. Microarrays were used to measure expression of mRNA and microRNA (miRNA) in dystrophic corneae. Results were validated by immunohistochemistry and Western blotting.

RESULTS:

Blood vessels and lymphatics grew from the limbus toward the dystrophic epithelium in corneae of KLEIP(-/-) mice. Blocking VEGF signaling did not reduce phenotype progression. Correspondingly, microarray analysis revealed no upregulation of canonical vascular growth factors in late dystrophy. During phenotype progression, angiopoietin-1 expression increased while miR-204 expression decreased. Bioinformatic analysis identified a binding site for miR-204 in the angiopoietin-1 gene. Validation by in vitro experiments confirmed regulation of angiopoietin-1 by miR-204.

CONCLUSIONS:

Vascular endothelial growth factor does not act as a major player in corneal neovascularization in KLEIP(-/-) mice. However, the proangiogenic factor angiopoietin-1 was strongly upregulated in late-stage phenotype, correlating with loss of miR-204 expression. Correspondingly, we identified miR-204 as a novel regulator of angiopoietin-1 in vitro. These findings may explain the incomplete efficacy of anti-VEGF therapy in the clinic and may provide new candidates for pharmaceutical intervention.

• Authors: Jakob N Kather, Julian Friedrich, Nicole Woik, Carsten Sticht, Norbert Gretz, Hans-Peter Hammes, Jens Kroll
• Journal: Investigative ophthalmology & visual science (Invest Ophthalmol Vis Sci) Vol. 55 Issue 7 Pg. 4295-303 (Jun 10 2014) ISSN: 1552-5783 [Electronic] United States
• PMID: 24917145 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Chemical References

• Angiogenesis Inhibitors
• Angiopoietin-1
• DNA-Binding Proteins
• MIRN204 microRNA, mouse
• MicroRNAs
• RNA, Messenger
• Vascular Endothelial Growth Factor A
• kleisen beta protein, mouse

Topics

• Angiogenesis Inhibitors (administration & dosage)
• Angiopoietin-1 (biosynthesis, genetics)
• Animals
• Blotting, Western
• Corneal Neovascularization (drug therapy, genetics, metabolism)
• DNA-Binding Proteins (deficiency)
• Disease Models, Animal
• Gene Expression Regulation
• Immunohistochemistry
• Intravitreal Injections
• Mice
• Mice, Knockout
• MicroRNAs (biosynthesis, genetics)
• Oligonucleotide Array Sequence Analysis
• Phenotype
• RNA, Messenger (genetics)
• Vascular Endothelial Growth Factor A (antagonists & inhibitors)