Lancaster EPrints

Effects of Aberrant Pax6 Gene Dosage on Mouse Corneal Pathophysiology and Corneal Epithelial Homeostasis

Mort, Richard L. and Bentley, Adam J. and Martin, Francis L. and Collinson, J. Martin and Douvaras, Panagiotis and Hill, Robert E. and Morley, Steven D. and Fullwood, Nigel J. and West, John D. (2011) Effects of Aberrant Pax6 Gene Dosage on Mouse Corneal Pathophysiology and Corneal Epithelial Homeostasis. PloS ONE, 6 (12). -. ISSN 1932-6203

[img]
Preview
PDF - Published Version
Download (1917Kb) | Preview

    Abstract

    Background: Altered dosage of the transcription factor PAX6 causes multiple human eye pathophysiologies. PAX6(+/-) heterozygotes suffer from aniridia and aniridia-related keratopathy (ARK), a corneal deterioration that probably involves a limbal epithelial stem cell (LESC) deficiency. Heterozygous Pax6(+/Sey-Neu) (Pax6(+/-)) mice recapitulate the human disease and are a good model of ARK. Corneal pathologies also occur in other mouse Pax6 mutants and in PAX77(Tg/-) transgenics, which over-express Pax6 and model human PAX6 duplication. Methodology/Principal Findings: We used electron microscopy to investigate ocular defects in Pax6(+/-) heterozygotes (low Pax6 levels) and PAX77(Tg/-) transgenics (high Pax6 levels). As well as the well-documented epithelial defects, aberrant Pax6 dosage had profound effects on the corneal stroma and endothelium in both genotypes, including cellular vacuolation, similar to that reported for human macular corneal dystrophy. We used mosaic expression of an X-linked LacZ transgene in X-inactivation mosaic female (XLacZ(Tg/-)) mice to investigate corneal epithelial maintenance by LESC clones in Pax6(+/-) and PAX77(Tg/-) mosaic mice. PAX77(Tg/-) mosaics, over-expressing Pax6, produced normal corneal epithelial radial striped patterns (despite other corneal defects), suggesting that centripetal cell movement was unaffected. Moderately disrupted patterns in Pax6(+/-) mosaics were corrected by introducing the PAX77 transgene (in Pax6(+/-), PAX77(Tg/-) mosaics). Pax6(Leca4/+), XLacZ(Tg/-) mosaic mice (heterozygous for the Pax6(Leca4) missense mutation) showed more severely disrupted mosaic patterns. Corrected corneal epithelial stripe numbers (an indirect estimate of active LESC clone numbers) declined with age (between 15 and 30 weeks) in wild-type XLacZ(Tg/-) mosaics. In contrast, corrected stripe numbers were already low at 15 weeks in Pax6(+/-) and PAX77(Tg/-) mosaic corneas, suggesting Pax6 under-and over-expression both affect LESC clones. Conclusions/Significance: Pax6(+/-) and PAX77(Tg/-) genotypes have only relatively minor effects on LESC clone numbers but cause more severe corneal endothelial and stromal defects. This should prompt further investigations of the pathophysiology underlying human aniridia and ARK.

    Item Type: Article
    Journal or Publication Title: PloS ONE
    Additional Information: Copyright: © 2011 Mort et al. 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 author and source are credited.
    Subjects: Q Science > QH Natural history > QH301 Biology
    Departments: Faculty of Health and Medicine > Biomedical & Life Sciences
    Faculty of Science and Technology > Lancaster Environment Centre
    ID Code: 59901
    Deposited By: ep_importer_pure
    Deposited On: 08 Nov 2012 13:33
    Refereed?: Yes
    Published?: Published
    Last Modified: 10 Apr 2014 00:18
    Identification Number:
    URI: http://eprints.lancs.ac.uk/id/eprint/59901

    Actions (login required)

    View Item