Effect of vascular endothelial growth factor upregulation on retinal gene expression in the Kimba mouse

Authors

  • Nicolette Binz PhD,

    Corresponding author
    1. Department of Molecular Ophthalmology, Lions Eye Institute, Nedlands
    2. Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia
      Dr Nicolette Binz, Lions Eye Institute, 2 Verdun Street, Nedlands, WA 6009, Australia. Email: binz@iinet.net.au
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  • Ireni S Ali Rahman PhD,

    1. Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia
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  • Holly R Chinnery PhD,

    1. Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia
    2. Department of Anatomy and Developmental Biology, Monash University, Clayton
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  • Richard McKeone PhD,

    1. Department of Molecular Ophthalmology, Lions Eye Institute, Nedlands
    2. Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia
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  • Ken M Simpson PhD,

    1. Division of Bioinformatics, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
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  • Terence P Speed PhD,

    1. Division of Bioinformatics, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
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  • Chooi-May Lai PhD,

    1. Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia
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  • P Elizabeth Rakoczy PhD

    1. Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia
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  • Competing/conflicts of interest: No stated conflict of interest.

  • Funding sources: Supported by the Juvenile Diabetes Research Foundation (USA), WestPac grant-in-aid (Australia) and the National Health and Medical Research Council of Australia (NHMRC project grant 353599). TPS and KMS received funding from the Medical Bioinformatics, Genomics and Proteomics Program (NHMRC Application ID 406657). NB receives financial support from the Lions Save-Sight Foundation of Western Australia, Inc. through the Brian King Postdoctoral Research Fellowship. ISAR is recipient of a Brunei Darussalam Ministry of Education's Postgraduate Research Scholarship.

Dr Nicolette Binz, Lions Eye Institute, 2 Verdun Street, Nedlands, WA 6009, Australia. Email: binz@iinet.net.au

Abstract

Background:  The Kimba mouse carries a human vascular endothelial growth factor transgene causing retinal neovascularisation similar to that seen in diabetic retinopathy. Here, we examine the relationship between differential gene expression induced by vascular endothelial growth factor overexpression and the architectural changes that occur in the retinae of these mice.

Methods:  Retinal gene expression changes in juvenile and adult Kimba mice were assayed by microarray and compared with age-matched wild-type littermates. Transcription of selected genes was validated by quantitative real-time polymerase chain reaction. Protein translation was determined using immunohistochemistry and enzyme-linked immunosorbent assay.

Results:  Semaphorin 3C was upregulated, and nuclear receptor subfamily 2, group 3, member 3 (Nr2e3) was downregulated in juvenile Kimba mice. Betacellulin and endothelin 2 were upregulated in adults. Semaphorin 3C colocalized with glial fibrillary acidic protein in Müller cells of Kimba retinae at greater signal intensities than in wild type. Endothelin 2 colocalised to Müller cell end feet and extended into the outer limiting membrane. Endothelin receptor type B staining was most pronounced in the inner nuclear layer, the region containing Müller cell somata.

Conclusions:  An early spike in vascular endothelial growth factor induced significant long-term retinal neovascularisation associated with changes to the retinal ganglion, photoreceptor and Müller cells. Overexpression of vascular endothelial growth factor led to dysregulation of photoreceptor metabolism through differential expression of Nr2e3, endothelin 2, betacellulin and semaphorin 3C. Alterations in the expression of these genes may therefore play key roles in the pathological mechanisms that result from retinal neovascularisation.

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