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Fuhrmann S, Ramirez S, Mina Abouda M, Campbell CD. Porcn is essential for growth and invagination of the mammalian optic cup. Front Cell Dev Biol 2022; 10:1016182. [PMID: 36393832 PMCID: PMC9661423 DOI: 10.3389/fcell.2022.1016182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 10/04/2022] [Indexed: 11/13/2022] Open
Abstract
Microphthalmia, anophthalmia, and coloboma (MAC) are congenital ocular malformations causing 25% of childhood blindness. The X-linked disorder Focal Dermal Hypoplasia (FDH) is frequently associated with MAC and results from mutations in Porcn, a membrane bound O-acyl transferase required for palmitoylation of Wnts to activate multiple Wnt-dependent pathways. Wnt/β-catenin signaling is suppressed in the anterior neural plate for initiation of eye formation and is subsequently required during differentiation of the retinal pigment epithelium (RPE). Non-canonical Wnts are critical for early eye formation in frog and zebrafish. However, it is unclear whether this also applies to mammals. We performed ubiquitous conditional inactivation of Porcn in mouse around the eye field stage. In PorcnCKO, optic vesicles (OV) arrest in growth and fail to form an optic cup. Ventral proliferation is significantly decreased in the mutant OV, with a concomitant increase in apoptotic cell death. While pan-ocular transcription factors such as PAX6, SIX3, LHX2, and PAX2 are present, indicative of maintenance of OV identity, regional expression of VSX2, MITF, OTX2, and NR2F2 is downregulated. Failure of RPE differentiation in PorcnCKO is consistent with downregulation of the Wnt/β-catenin effector LEF1, starting around 2.5 days after inactivation. This suggests that Porcn inactivation affects signaling later than a potential requirement for Wnts to promote eye field formation. Altogether, our data shows a novel requirement for Porcn in regulating growth and morphogenesis of the OV, likely by controlling proliferation and survival. In FDH patients with ocular manifestations, growth deficiency during early ocular morphogenesis may be the underlying cause for microphthalmia.
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Affiliation(s)
- Sabine Fuhrmann
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
- Department of Cell and Developmental Biology, Vanderbilt University Medical School, Nashville, TN, United States
- *Correspondence: Sabine Fuhrmann,
| | - Sara Ramirez
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
- Department of Cell and Developmental Biology, Vanderbilt University Medical School, Nashville, TN, United States
| | - Mirna Mina Abouda
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Clorissa D. Campbell
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
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Najarro EH, Huang J, Jacobo A, Quiruz LA, Grillet N, Cheng AG. Dual regulation of planar polarization by secreted Wnts and Vangl2 in the developing mouse cochlea. Development 2020; 147:dev.191981. [PMID: 32907846 DOI: 10.1242/dev.191981] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 08/24/2020] [Indexed: 12/14/2022]
Abstract
Planar cell polarity (PCP) proteins localize asymmetrically to instruct cell polarity within the tissue plane, with defects leading to deformities of the limbs, neural tube and inner ear. Wnt proteins are evolutionarily conserved polarity cues, yet Wnt mutants display variable PCP defects; thus, how Wnts regulate PCP remains unresolved. Here, we have used the developing cochlea as a model system to show that secreted Wnts regulate PCP through polarizing a specific subset of PCP proteins. Conditional deletion of Wntless or porcupine, both of which are essential for secretion of Wnts, caused misrotated sensory cells and shortened cochlea - both hallmarks of PCP defects. Wntless-deficient cochleae lacked the polarized PCP components dishevelled 1/2 and frizzled 3/6, while other PCP proteins (Vangl1/2, Celsr1 and dishevelled 3) remained localized. We identified seven Wnt paralogues, including the major PCP regulator Wnt5a, which was, surprisingly, dispensable for planar polarization in the cochlea. Finally, Vangl2 haploinsufficiency markedly accentuated sensory cell polarization defects in Wntless-deficient cochlea. Together, our study indicates that secreted Wnts and Vangl2 coordinate to ensure proper tissue polarization during development.
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Affiliation(s)
- Elvis Huarcaya Najarro
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jennifer Huang
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Adrian Jacobo
- Laboratory of Sensory Neuroscience, The Rockefeller University, New York, NY 10065, USA
| | - Lee A Quiruz
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Nicolas Grillet
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alan G Cheng
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
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Bhutta MF, Thornton RB, Kirkham LAS, Kerschner JE, Cheeseman MT. Understanding the aetiology and resolution of chronic otitis media from animal and human studies. Dis Model Mech 2018; 10:1289-1300. [PMID: 29125825 PMCID: PMC5719252 DOI: 10.1242/dmm.029983] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Inflammation of the middle ear, known clinically as chronic otitis media, presents in different forms, such as chronic otitis media with effusion (COME; glue ear) and chronic suppurative otitis media (CSOM). These are highly prevalent diseases, especially in childhood, and lead to significant morbidity worldwide. However, much remains unclear about this disease, including its aetiology, initiation and perpetuation, and the relative roles of mucosal and leukocyte biology, pathogens, and Eustachian tube function. Chronic otitis media is commonly modelled in mice but most existing models only partially mimic human disease and many are syndromic. Nevertheless, these models have provided insights into potential disease mechanisms, and have implicated altered immune signalling, mucociliary function and Eustachian tube function as potential predisposing mechanisms. Clinical studies of chronic otitis media have yet to implicate a particular molecular pathway or mechanism, and current human genetic studies are underpowered. We also do not fully understand how existing interventions, such as tympanic membrane repair, work, nor how chronic otitis media spontaneously resolves. This Clinical Puzzle article describes our current knowledge of chronic otitis media and the existing research models for this condition. It also identifies unanswered questions about its pathogenesis and treatment, with the goal of advancing our understanding of this disease to aid the development of novel therapeutic interventions. Summary: Chronic middle ear inflammation is a common disease. Animal models, and in particular mouse models, have been used to elucidate some potential mechanisms, including dysfunction in immune signalling, mucociliary function or Eustachian tube function.
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Affiliation(s)
- Mahmood F Bhutta
- Department of ENT, Brighton and Sussex University Hospitals NHS Trust, Brighton, BN2 5BE, England .,Division of Paediatrics, University of Western Australia, Subiaco, WA 6008, Australia
| | - Ruth B Thornton
- Division of Paediatrics, University of Western Australia, Subiaco, WA 6008, Australia.,Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Subiaco, WA 6008, Australia
| | - Lea-Ann S Kirkham
- Division of Paediatrics, University of Western Australia, Subiaco, WA 6008, Australia.,Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Subiaco, WA 6008, Australia
| | - Joseph E Kerschner
- Office of the Dean, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Michael T Cheeseman
- Division of Developmental Biology, Roslin Institute, University of Edinburgh, Midlothian, EH23 9RG, Scotland
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Wright JT, Puranik CP, Farrington F. Oral phenotype and variation in focal dermal hypoplasia. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2016; 172C:52-8. [DOI: 10.1002/ajmg.c.31478] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Muñoz-Descalzo S, Hadjantonakis AK, Arias AM. Wnt/ß-catenin signalling and the dynamics of fate decisions in early mouse embryos and embryonic stem (ES) cells. Semin Cell Dev Biol 2015; 47-48:101-9. [PMID: 26321498 DOI: 10.1016/j.semcdb.2015.08.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 08/18/2015] [Accepted: 08/20/2015] [Indexed: 12/22/2022]
Abstract
Wnt/ß-catenin signalling is a widespread cell signalling pathway with multiple roles during vertebrate development. In mouse embryonic stem (mES) cells, there is a dual role for ß-catenin: it promotes differentiation when activated as part of the Wnt/ß-catenin signalling pathway, and promotes stable pluripotency independently of signalling. Although mES cells resemble the preimplantation epiblast progenitors, the first requirement for Wnt/ß-catenin signalling during mouse development has been reported at implantation [1,2]. The relationship between ß-catenin and pluripotency and that of mES cells with epiblast progenitors suggests that ß-catenin might have a functional role during preimplantation development. Here we summarize the expression and function of Wnt/ß-catenin signalling elements during the early stages of mouse development and consider the reasons why the requirement in ES cells do not reflect the embryo.
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Affiliation(s)
| | - Anna-Katerina Hadjantonakis
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
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Locke MEO, Milojevic M, Eitutis ST, Patel N, Wishart AE, Daley M, Hill KA. Genomic copy number variation in Mus musculus. BMC Genomics 2015; 16:497. [PMID: 26141061 PMCID: PMC4490682 DOI: 10.1186/s12864-015-1713-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 06/22/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Copy number variation is an important dimension of genetic diversity and has implications in development and disease. As an important model organism, the mouse is a prime candidate for copy number variant (CNV) characterization, but this has yet to be completed for a large sample size. Here we report CNV analysis of publicly available, high-density microarray data files for 351 mouse tail samples, including 290 mice that had not been characterized for CNVs previously. RESULTS We found 9634 putative autosomal CNVs across the samples affecting 6.87% of the mouse reference genome. We find significant differences in the degree of CNV uniqueness (single sample occurrence) and the nature of CNV-gene overlap between wild-caught mice and classical laboratory strains. CNV-gene overlap was associated with lipid metabolism, pheromone response and olfaction compared to immunity, carbohydrate metabolism and amino-acid metabolism for wild-caught mice and classical laboratory strains, respectively. Using two subspecies of wild-caught Mus musculus, we identified putative CNVs unique to those subspecies and show this diversity is better captured by wild-derived laboratory strains than by the classical laboratory strains. A total of 9 genic copy number variable regions (CNVRs) were selected for experimental confirmation by droplet digital PCR (ddPCR). CONCLUSION The analysis we present is a comprehensive, genome-wide analysis of CNVs in Mus musculus, which increases the number of known variants in the species and will accelerate the identification of novel variants in future studies.
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Affiliation(s)
- M Elizabeth O Locke
- Department of Computer Science, The University of Western Ontario, London, ON, N6A 5B7, Canada.
| | - Maja Milojevic
- Department of Biology, The University of Western Ontario, Biological and Geological Sciences Building 1151 Richmond St. N, London, ON, N6A 5B7, Canada.
| | - Susan T Eitutis
- Department of Biology, The University of Western Ontario, Biological and Geological Sciences Building 1151 Richmond St. N, London, ON, N6A 5B7, Canada.
| | - Nisha Patel
- Department of Biology, The University of Western Ontario, Biological and Geological Sciences Building 1151 Richmond St. N, London, ON, N6A 5B7, Canada.
| | - Andrea E Wishart
- Department of Biology, The University of Western Ontario, Biological and Geological Sciences Building 1151 Richmond St. N, London, ON, N6A 5B7, Canada.
| | - Mark Daley
- Department of Computer Science, The University of Western Ontario, London, ON, N6A 5B7, Canada.
- Department of Biology, The University of Western Ontario, Biological and Geological Sciences Building 1151 Richmond St. N, London, ON, N6A 5B7, Canada.
| | - Kathleen A Hill
- Department of Computer Science, The University of Western Ontario, London, ON, N6A 5B7, Canada.
- Department of Biology, The University of Western Ontario, Biological and Geological Sciences Building 1151 Richmond St. N, London, ON, N6A 5B7, Canada.
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Bankhead EJ, Colasanto MP, Dyorich KM, Jamrich M, Murtaugh LC, Fuhrmann S. Multiple requirements of the focal dermal hypoplasia gene porcupine during ocular morphogenesis. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 185:197-213. [PMID: 25451153 DOI: 10.1016/j.ajpath.2014.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 08/25/2014] [Accepted: 09/02/2014] [Indexed: 12/13/2022]
Abstract
Wnt glycoproteins control key processes during development and disease by activating various downstream pathways. Wnt secretion requires post-translational modification mediated by the O-acyltransferase encoded by the Drosophila porcupine homolog gene (PORCN). In humans, PORCN mutations cause focal dermal hypoplasia (FDH, or Goltz syndrome), an X-linked dominant multisystem birth defect that is frequently accompanied by ocular abnormalities such as coloboma, microphthalmia, or even anophthalmia. Although genetic ablation of Porcn in mouse has provided insight into the etiology of defects caused by ectomesodermal dysplasia in FDH, the requirement for Porcn and the actual Wnt ligands during eye development have been unknown. In this study, Porcn hemizygosity occasionally caused ocular defects reminiscent of FDH. Conditional inactivation of Porcn in periocular mesenchyme led to defects in mid- and hindbrain and in craniofacial development, but was insufficient to cause ocular abnormalities. However, a combination of conditional Porcn depletion in optic vesicle neuroectoderm, lens, and neural crest-derived periocular mesenchyme induced severe eye abnormalities with high penetrance. In particular, we observed coloboma, transdifferentiation of the dorsal and ventral retinal pigment epithelium, defective optic cup periphery, and closure defects of the eyelid, as well as defective corneal morphogenesis. Thus, Porcn is required in both extraocular and neuroectodermal tissues to regulate distinct Wnt-dependent processes during morphogenesis of the posterior and anterior segments of the eye.
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Affiliation(s)
- Elizabeth J Bankhead
- Departments of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah
| | - Mary P Colasanto
- Departments of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah
| | - Kayla M Dyorich
- Departments of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah
| | - Milan Jamrich
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | | | - Sabine Fuhrmann
- Departments of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah.
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