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Duncan MK, Daruich A, Valleix S, Bremond-Gignac D. Reduction of lens size in PAX6-related aniridia. Exp Eye Res 2024; 238:109746. [PMID: 38056551 PMCID: PMC10843565 DOI: 10.1016/j.exer.2023.109746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 12/08/2023]
Abstract
Heterozygous mutation of PAX6 in humans leads to congenital aniridia (OMIM 106210) which is typified by congenital iris and foveal defects, and later onset glaucoma, aniridic keratopathy, and cataract. Mice heterozygous for Pax6 mutations phenocopy many aspects of aniridia including the iris defects, keratopathy and cataract, although Pax6 mutant mice have small lenses, a phenotype which is not typically reported in human aniridia, perhaps due to difficulties in measuring lens diameter during typical ophthalmic examinations as the lens periphery is shielded by the iris. In order to overcome this, records of patients diagnosed with congenital aniridia between April 2015 and May 2021 at the Necker-Enfants Malades Hospital, and genetically confirmed with a disease-causing PAX6 variant, were retrospectively reviewed for those with normal axial length whose iris defects allowed visualization of the lens margins and corneal diameter to allow calculation of a lens/corneal diameter ratio. This value was compared with values obtained from a cohort of patients with Sjödell grade IV oculocutaneous albinism type 1 (OCA1; OMIM 203100) which allowed visualization of the lens periphery via iris transillumination. This analysis revealed that patients with congenital aniridia had a significantly lower lens/corneal ratio when compared to those with albinism, suggesting that humans haploinsufficient for PAX6, like mice, rats, frogs, and zebrafish, exhibit reductions in lens size.
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Affiliation(s)
- Melinda K Duncan
- Department of Biological Sciences, University of Delaware, Newark, DE, 19716, USA.
| | - Alejandra Daruich
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France; INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France
| | - Sophie Valleix
- INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France; Service de Médecine Génomique des Maladies de Système et d'Organe, APHP Centre, Paris, Université de Paris Cité, Fédération de Génétique et de Médecine Génomique, Hôpital Cochin, 27 rue du Fbg St-Jacques, 75679, Paris, Cedex 14, France
| | - Dominique Bremond-Gignac
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France; INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France
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Analysis of compound heterozygotes reveals that the mouse floxed Pax6 (tm1Ued) allele produces abnormal eye phenotypes. Transgenic Res 2016; 25:679-92. [PMID: 27240603 PMCID: PMC5023747 DOI: 10.1007/s11248-016-9962-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 05/13/2016] [Indexed: 01/27/2023]
Abstract
Analysis of abnormal phenotypes produced by different types of mutations has been crucial for our understanding of gene function. Some floxed alleles that retain a neomycin-resistance selection cassette (neo cassette) are not equivalent to wild-type alleles and provide useful experimental resources. Pax6 is an important developmental gene and the aim of this study was to determine whether the floxed Pax6tm1Ued (Pax6fl) allele, which has a retained neo cassette, produced any abnormal eye phenotypes that would imply that it differs from the wild-type allele. Homozygous Pax6fl/fl and heterozygous Pax6fl/+ mice had no overt qualitative eye abnormalities but morphometric analysis showed that Pax6fl/fl corneas tended be thicker and smaller in diameter. To aid identification of weak effects, we produced compound heterozygotes with the Pax6Sey-Neu (Pax6−) null allele. Pax6fl/− compound heterozygotes had more severe eye abnormalities than Pax6+/− heterozygotes, implying that Pax6fl differs from the wild-type Pax6+ allele. Immunohistochemistry showed that the Pax6fl/− corneal epithelium was positive for keratin 19 and negative for keratin 12, indicating that it was abnormally differentiated. This Pax6fl allele provides a useful addition to the existing Pax6 allelic series and this study demonstrates the utility of using compound heterozygotes with null alleles to unmask cryptic effects of floxed alleles.
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Curto GG, Gard C, Ribes V. Structures and properties of PAX linked regulatory networks architecting and pacing the emergence of neuronal diversity. Semin Cell Dev Biol 2015; 44:75-86. [DOI: 10.1016/j.semcdb.2015.09.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 09/07/2015] [Accepted: 09/16/2015] [Indexed: 12/13/2022]
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Huettl RE, Eckstein S, Stahl T, Petricca S, Ninkovic J, Götz M, Huber AB. Functional dissection of the Pax6 paired domain: Roles in neural tube patterning and peripheral nervous system development. Dev Biol 2015; 413:86-103. [PMID: 26187199 DOI: 10.1016/j.ydbio.2015.07.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 06/21/2015] [Accepted: 07/11/2015] [Indexed: 10/23/2022]
Abstract
During development of the CNS, stem and progenitor cell proliferation, cell fate designation, and patterning decisions are tightly regulated by interdependent networks of key transcriptional regulators. In a genetic approach we analyzed divergent functionality of the PAI and RED sub-domains of the Pax6 Paired domain (PD) during progenitor zone formation, motor and interneuron development, and peripheral connectivity at distinct levels within the neural tube: within the hindbrain, mutation of the PAI sub-domain severely affected patterning of the p3 and pMN domains and establishment of the corresponding motor neurons. Exit point designation of hypoglossal axons was disturbed in embryos harboring either mutations in the PD sub-domains or containing a functional Pax6 Null allele. At brachial spinal levels, we propose a selective involvement of the PAI sub-domain during patterning of ventral p2 and pMN domains, critically disturbing generation of specific motor neuron subtypes and increasing V2 interneuron numbers. Our findings present a novel aspect of how Pax6 not only utilizes its modular structure to perform distinct functions via its paired and homeodomain. Individual sub-domains can exert distinct functions, generating a new level of complexity for transcriptional regulation by one single transcription factor not only in dorso-ventral, but also rostro-caudal neural tube patterning.
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Affiliation(s)
- Rosa-Eva Huettl
- Institute of Developmental Genetics, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Simone Eckstein
- Institute of Developmental Genetics, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Tessa Stahl
- Institute of Stem Cell Research, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Stefania Petricca
- Institute of Stem Cell Research, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Jovica Ninkovic
- Institute of Stem Cell Research, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Magdalena Götz
- Institute of Stem Cell Research, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Andrea B Huber
- Institute of Developmental Genetics, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
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Dorà NJ, Collinson JM, Hill RE, West JD. Hemizygous Le-Cre transgenic mice have severe eye abnormalities on some genetic backgrounds in the absence of LoxP sites. PLoS One 2014; 9:e109193. [PMID: 25272013 PMCID: PMC4182886 DOI: 10.1371/journal.pone.0109193] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 08/29/2014] [Indexed: 11/18/2022] Open
Abstract
Eye phenotypes were investigated in Le-CreTg/−; Pax6fl/+ mice, which were expected to show tissue-specific reduction of Pax6 in surface ectoderm derivatives. To provide a better comparison with our previous studies of Pax6+/− eye phenotypes, hemizygous Le-CreTg/− and heterozygous Pax6fl/+mice were crossed onto the CBA/Ca genetic background. After the Le-Cre transgene had been backcrossed to CBA/Ca for seven generations, significant eye abnormalities occurred in some hemizygous Le-CreTg/−; Pax6+/+ controls (without a floxed Pax6fl allele) as well as experimental Le-CreTg/−; Pax6fl/+ mice. However, no abnormalities were seen in Le-Cre−/−; Pax6fl/+ or Le-Cre−/−; Pax6+/+ controls (without the Le-Cre transgene). The severity and frequency of the eye abnormalities in Le-CreTg/−; Pax6+/+ control mice diminished after backcrossing Le-CreTg/− mice to the original FVB/N strain for two generations, showing that the effect was reversible. This genetic background effect suggests that the eye abnormalities are a consequence of an interaction between the Le-Cre transgene and alleles of unknown modifier genes present in certain genetic backgrounds. The abnormalities were also ameliorated by introducing additional Pax6 gene copies on a CBA/Ca background, suggesting involvement of Pax6 depletion in Le-CreTg/−; Pax6+/+ mice rather than direct action of Cre recombinase on cryptic pseudo-loxP sites. One possibility is that expression of Cre recombinase from the Pax6-Le regulatory sequences in the Le-Cre transgene depletes cofactors required for endogenous Pax6 gene expression. Our observation that eye abnormalities can occur in hemizygous Le-CreTg/−; Pax6+/+ mice, in the absence of a floxed allele, demonstrates the importance of including all the relevant genetic controls in Cre-loxP experiments.
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Affiliation(s)
- Natalie J. Dorà
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - J. Martin Collinson
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Robert E. Hill
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - John D. West
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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Fei P, Zhang Q, Li J, Zhao P. Clinical characteristics and treatment of 22 eyes of morning glory syndrome associated with persistent hyperplastic primary vitreous. Br J Ophthalmol 2013; 97:1262-7. [PMID: 23878133 PMCID: PMC3786642 DOI: 10.1136/bjophthalmol-2013-303565] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
PURPOSE To describe the clinical manifestations and treatment outcomes in a retrospective case series of morning glory syndrome (MGS) associated with persistent hyperplastic primary vitreous (PHPV). METHODS The medical records of 85 eyes/74 patients referred for ophthalmology consultation diagnosed as MGS in our clinic were reviewed retrospectively. All patients underwent thorough ophthalmological examinations. 22 eyes of 19 patients diagnosed as having MGS associated with PHPV were included, accounting for 25.88% of all the MGS eyes. Clinical manifestations and management of these patients were documented. RESULTS 15 patients (78.95%) were younger than 1 year old at the first diagnosis. Six eyes were associated with microphthalmia. 19 of 22 eyes (86.36%) had complications, including cataract (10 eyes), secondary glaucoma (8 eyes), corneal leucoma or oedema (8 eyes), retinal detachment (8 eyes), strabismus (3 eyes) and nystagmus (2 eyes). Treatment methods varied depending on the severity of the complications. Nine eyes with secondary glaucoma or cataract got lensectomy; three eyes underwent combined vitrectomy and lensectomy. Eight patients underwent cranial MRI/MR angiography or CT examination. Widened cerebral fissures of bilateral temporal lobes, abnormal dilated branch of middle cerebral artery in the left hemisphere and abnormal signal in the grey matter of frontal and occipital lobes were revealed respectively in three patients. CONCLUSIONS Our study revealed the coexistence of PHPV in a significant percentage of patients with MGS, suggesting a potential common genetic link. Compared with MGS and PHPV alone, the combination of the two conditions manifested with higher incidence and more severe complications in younger patients. Close follow-up was recommended. Lensectomy and vitrectomy were beneficial in the management of the complications.
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Affiliation(s)
- Ping Fei
- Department of Ophthalmology, Xinhua Hospital, affiliated to Shanghai Jiaotong University School of Medicine, , Shanghai, China
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Mort RL, Bentley AJ, Martin FL, Collinson JM, Douvaras P, Hill RE, Morley SD, Fullwood NJ, West JD. Effects of aberrant Pax6 gene dosage on mouse corneal pathophysiology and corneal epithelial homeostasis. PLoS One 2011; 6:e28895. [PMID: 22220198 PMCID: PMC3248408 DOI: 10.1371/journal.pone.0028895] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 11/16/2011] [Indexed: 11/18/2022] Open
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 PAX77Tg/− 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 PAX77Tg/− 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 (XLacZTg/−) mice to investigate corneal epithelial maintenance by LESC clones in Pax6+/− and PAX77Tg/− mosaic mice. PAX77Tg/− 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+/−, PAX77Tg/− mosaics). Pax6Leca4/+, XLacZTg/− mosaic mice (heterozygous for the Pax6Leca4 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 XLacZTg/− mosaics. In contrast, corrected stripe numbers were already low at 15 weeks in Pax6+/− and PAX77Tg/− mosaic corneas, suggesting Pax6 under- and over-expression both affect LESC clones. Conclusions/Significance Pax6+/− and PAX77Tg/− 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.
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Affiliation(s)
- Richard L. Mort
- Division of Reproductive and Developmental Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Adam J. Bentley
- Division of Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom
| | - Francis L. Martin
- Centre for Biophotonics, Lancaster University, Lancaster, United Kingdom
| | - J. Martin Collinson
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Panagiotis Douvaras
- Division of Reproductive and Developmental Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Robert E. Hill
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Steven D. Morley
- School of Clinical Sciences & Community Health, University of Edinburgh, Edinburgh, United Kingdom
| | - Nigel J. Fullwood
- Division of Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom
| | - John D. West
- Division of Reproductive and Developmental Sciences, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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Davis J, Piatigorsky J. Overexpression of Pax6 in mouse cornea directly alters corneal epithelial cells: changes in immune function, vascularization, and differentiation. Invest Ophthalmol Vis Sci 2011; 52:4158-68. [PMID: 21447684 DOI: 10.1167/iovs.10-6726] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
PURPOSE To assess whether Pax6 functions directly in the cornea, a corneal-preferred promoter was used to overexpress Pax6 specifically in the cornea. METHODS Transgenic mice harboring a construct containing mouse Pax6 coding sequences fused downstream of the aldehyde dehydrogenase 3a1 (Aldh3a1) promoter were generated (Pax6 Tg). Pax6 expression was analyzed by Western blot and immunohistochemistry. Eye sections were stained with hematoxylin and eosin, Schiff reagent, and fluorescein, to assess morphologic changes, the presence of goblet cells, and barrier integrity, respectively. Gene expression changes in mildly affected Pax6 Tg corneas were compared to age-matched, wild-type (WT) corneas by microarray analysis and quantitative PCR. Promoter regulation of several differentially expressed genes was examined by monitoring luciferase activity of reporter constructs after cotransfection with Pax6 in COS7 cells. RESULTS Corneal overexpression of Pax6 produces an abnormal cornea with altered epithelial cell morphology, neovascularization, immune cell invasion, and a compromised barrier; the lens appeared normal. Major changes in expression of genes involved in immune function, vascularization, and epithelial differentiation occurred in corneas from Pax6 Tg versus WT mice. The keratin (K) profile was dramatically altered in the Pax6 Tg corneas, as were several components of the Wnt signaling pathway. In severely affected Pax6 Tg corneas, K12 was reduced, and Pax6 was redistributed into the cytoplasm. Promoters from the chitinase 3-like 3, Wnt inhibitory factor 1, and fms-related tyrosine kinase 1/soluble VEGF receptor genes were upregulated five-, seven-, and threefold, respectively, by Pax6 in transfected COS7 cells. CONCLUSIONS Pax6 functions directly to maintain normal, corneal epithelial cells.
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Affiliation(s)
- Janine Davis
- Laboratory of Molecular and Developmental Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA.
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