1
|
Cozzitorto C, Peltz Z, Flores LM, Della Santina L, Mao M, Gould DB. Evaluating neural crest cell migration in a Col4a1 mutant mouse model of ocular anterior segment dysgenesis. Cells Dev 2024:203926. [PMID: 38729574 DOI: 10.1016/j.cdev.2024.203926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 05/02/2024] [Accepted: 05/06/2024] [Indexed: 05/12/2024]
Abstract
The periocular mesenchyme (POM) is a transient migratory embryonic tissue derived from neural crest cells (NCCs) and paraxial mesoderm that gives rise to most of the structures in front of the eye. Morphogenetic defects of these structures can impair aqueous humor outflow, leading to elevated intraocular pressure and glaucoma. Mutations in collagen type IV alpha 1 (COL4A1) and alpha 2 (COL4A2) cause Gould syndrome - a multisystem disorder often characterized by variable cerebrovascular, ocular, renal, and neuromuscular manifestations. Approximately one-third of individuals with COL4A1 and COL4A2 mutations have ocular anterior segment dysgenesis (ASD), including congenital glaucoma resulting from abnormalities of POM-derived structures. POM differentiation has been a major focus of ASD research, but the underlying cellular mechanisms are still unclear. Moreover, earlier events including NCC migration and survival defects have been implicated in ASD; however, their roles are not as well understood. Vascular defects are among the most common consequences of COL4A1 and COL4A2 mutations and can influence NCC survival and migration. We therefore hypothesized that NCC migration might be impaired by COL4A1 and COL4A2 mutations. In this study, we used 3D confocal microscopy, gross morphology, and quantitative analyses to test NCC migration in Col4a1 mutant mice. We show that homozygous Col4a1 mutant embryos have severe embryonic growth retardation and lethality, and we identified a potential maternal effect on embryo development. Cerebrovascular defects in heterozygous Col4a1 mutant embryos were present as early as E9.0, showing abnormal cerebral vasculature plexus remodeling compared to controls. We detected abnormal NCC migration within the diencephalic stream and the POM in heterozygous Col4a1 mutants whereby mutant NCCs formed smaller diencephalic migratory streams and POMs. In these settings, migratory NCCs within the diencephalic stream and POM localize farther away from the developing vasculature. Our results show for the first time that Col4a1 mutations lead to cranial NCCs migratory defects in the context of early onset defective angiogenesis without affecting cell numbers, possibly impacting the relation between NCCs and the blood vessels during ASD development.
Collapse
Affiliation(s)
- Corinna Cozzitorto
- Department of Ophthalmology, University of California, San Francisco, CA 94158, United States.
| | - Zoe Peltz
- Department of Ophthalmology, University of California, San Francisco, CA 94158, United States
| | - Lourdes M Flores
- Department of Ophthalmology, University of California, San Francisco, CA 94158, United States
| | - Luca Della Santina
- Department of Ophthalmology, University of California, San Francisco, CA 94158, United States.
| | - Mao Mao
- Department of Ophthalmology, University of California, San Francisco, CA 94158, United States
| | - Douglas B Gould
- Department of Ophthalmology, University of California, San Francisco, CA 94158, United States; Department of Anatomy, Cardiovascular Research Institute, Bakar Aging Research Institute, and Institute for Human Genetics, University of California, San Francisco, United States.
| |
Collapse
|
2
|
Becker S, L'Ecuyer Z, Jones BW, Zouache MA, McDonnell FS, Vinberg F. Modeling complex age-related eye disease. Prog Retin Eye Res 2024; 100:101247. [PMID: 38365085 DOI: 10.1016/j.preteyeres.2024.101247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 01/31/2024] [Accepted: 02/02/2024] [Indexed: 02/18/2024]
Abstract
Modeling complex eye diseases like age-related macular degeneration (AMD) and glaucoma poses significant challenges, since these conditions depend highly on age-related changes that occur over several decades, with many contributing factors remaining unknown. Although both diseases exhibit a relatively high heritability of >50%, a large proportion of individuals carrying AMD- or glaucoma-associated genetic risk variants will never develop these diseases. Furthermore, several environmental and lifestyle factors contribute to and modulate the pathogenesis and progression of AMD and glaucoma. Several strategies replicate the impact of genetic risk variants, pathobiological pathways and environmental and lifestyle factors in AMD and glaucoma in mice and other species. In this review we will primarily discuss the most commonly available mouse models, which have and will likely continue to improve our understanding of the pathobiology of age-related eye diseases. Uncertainties persist whether small animal models can truly recapitulate disease progression and vision loss in patients, raising doubts regarding their usefulness when testing novel gene or drug therapies. We will elaborate on concerns that relate to shorter lifespan, body size and allometries, lack of macula and a true lamina cribrosa, as well as absence and sequence disparities of certain genes and differences in their chromosomal location in mice. Since biological, rather than chronological, age likely predisposes an organism for both glaucoma and AMD, more rapidly aging organisms like small rodents may open up possibilities that will make research of these diseases more timely and financially feasible. On the other hand, due to the above-mentioned anatomical and physiological features, as well as pharmacokinetic and -dynamic differences small animal models are not ideal to study the natural progression of vision loss or the efficacy and safety of novel therapies. In this context, we will also discuss the advantages and pitfalls of alternative models that include larger species, such as non-human primates and rabbits, patient-derived retinal organoids, and human organ donor eyes.
Collapse
Affiliation(s)
- Silke Becker
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Zia L'Ecuyer
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Bryan W Jones
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Moussa A Zouache
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Fiona S McDonnell
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA; Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Frans Vinberg
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA; Biomedical Engineering, University of Utah, Salt Lake City, UT, USA.
| |
Collapse
|
3
|
Taoka T, Ito R, Nakamichi R, Nakane T, Kawai H, Naganawa S. Interstitial Fluidopathy of the Central Nervous System: An Umbrella Term for Disorders with Impaired Neurofluid Dynamics. Magn Reson Med Sci 2024; 23:1-13. [PMID: 36436975 PMCID: PMC10838724 DOI: 10.2463/mrms.rev.2022-0012] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 08/29/2022] [Indexed: 01/05/2024] Open
Abstract
Interest in interstitial fluid dynamics has increased since the proposal of the glymphatic system hypothesis. Abnormal dynamics of the interstitial fluid have been pointed out to be an important factor in various pathological statuses. In this article, we propose the concept of central nervous system interstitial fluidopathy as a disease or condition in which abnormal interstitial fluid dynamics is one of the important factors for the development of a pathological condition. We discuss the aspects of interstitial fluidopathy in various diseases, including Alzheimer's disease, Parkinson's disease, normal pressure hydrocephalus, and cerebral small vessel disease. We also discuss a method called "diffusion tensor image analysis along the perivascular space" using MR diffusion images, which is used to evaluate the degree of interstitial fluidopathy or the activity of the glymphatic system.
Collapse
Affiliation(s)
- Toshiaki Taoka
- Department of Innovative Biomedical Visualization (iBMV), Nagoya University, Nagoya, Aichi, Japan
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Rintaro Ito
- Department of Innovative Biomedical Visualization (iBMV), Nagoya University, Nagoya, Aichi, Japan
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Rei Nakamichi
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Toshiki Nakane
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Hisashi Kawai
- Department of Radiology, Aichi Medical University, Nagakute, Aichi, Japan
| | - Shinji Naganawa
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| |
Collapse
|
4
|
Kuang L, Zhang M, Wang T, Huang T, Li J, Gan R, Yu M, Cao W, Yan X. The molecular genetics of anterior segment dysgenesis. Exp Eye Res 2023; 234:109603. [PMID: 37495069 DOI: 10.1016/j.exer.2023.109603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 07/19/2023] [Accepted: 07/22/2023] [Indexed: 07/28/2023]
Abstract
Anterior segment dysgenesis is a severe developmental eye disorder that leads to blindness in children. The exact mechanisms underlying this condition remain elusive. Recently, an increasing amount of studies have focused on genes and signal transduction pathways that affect anterior segment dysgenesis;these factors include transcription factors, developmental regulators, extracellular matrix genes, membrane-related proteins, cytoskeleton proteins and other associated genes. To date, dozens of gene variants have been found to cause anterior segment dysgenesis. However, there is still a lack of effective treatments. With a broader and deeper understanding of the molecular mechanisms underlying anterior segment development in the future, gene editing technology and stem cell technology may be new treatments for anterior segment dysgenesis. Further studies on the mechanisms of how different genes influence the onset and progression of anterior segment dysgenesis are still needed.
Collapse
Affiliation(s)
- Longhao Kuang
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, 518040, China
| | - Min Zhang
- School of Medicine, Anhui University of Science and Technology, Huainan, 232000, China
| | - Ting Wang
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, 518040, China
| | - Tao Huang
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, 518040, China
| | - Jin Li
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, 518040, China
| | - Run Gan
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, 518040, China
| | - Mingyu Yu
- Department of the Second Clinical Medical College, Jinan University (Shenzhen Eye Hospital), Shenzhen, 518020, China
| | - Wenchao Cao
- Department of the Second Clinical Medical College, Jinan University (Shenzhen Eye Hospital), Shenzhen, 518020, China
| | - Xiaohe Yan
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, 518040, China.
| |
Collapse
|
5
|
Ishikawa Y, Taga Y, Coste T, Tufa SF, Keene DR, Mizuno K, Tournier-Lasserve E, Gould DB. Lysyl hydroxylase 3-mediated post-translational modifications are required for proper biosynthesis of collagen α1α1α2(IV). J Biol Chem 2022; 298:102713. [PMID: 36403858 PMCID: PMC9761383 DOI: 10.1016/j.jbc.2022.102713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 11/05/2022] [Accepted: 11/09/2022] [Indexed: 11/19/2022] Open
Abstract
Collagens are the most abundant proteins in the body and among the most biosynthetically complex. A molecular ensemble of over 20 endoplasmic reticulum resident proteins participates in collagen biosynthesis and contributes to heterogeneous post-translational modifications. Pathogenic variants in genes encoding collagens cause connective tissue disorders, including osteogenesis imperfecta, Ehlers-Danlos syndrome, and Gould syndrome (caused by mutations in COL4A1 and COL4A2), and pathogenic variants in genes encoding proteins required for collagen biosynthesis can cause similar but overlapping clinical phenotypes. Notably, pathogenic variants in lysyl hydroxylase 3 (LH3) cause a multisystem connective tissue disorder that exhibits pathophysiological features of collagen-related disorders. LH3 is a multifunctional collagen-modifying enzyme; however, its precise role(s) and substrate specificity during collagen biosynthesis has not been defined. To address this critical gap in knowledge, we generated LH3 KO cells and performed detailed quantitative and molecular analyses of collagen substrates. We found that LH3 deficiency severely impaired secretion of collagen α1α1α2(IV) but not collagens α1α1α2(I) or α1α1α1(III). Amino acid analysis revealed that LH3 is a selective LH for collagen α1α1α2(IV) but a general glucosyltransferase for collagens α1α1α2(IV), α1α1α2(I), and α1α1α1(III). Importantly, we identified rare variants that are predicted to be pathogenic in the gene encoding LH3 in two of 113 fetuses with intracranial hemorrhage-a cardinal feature of Gould syndrome. Collectively, our findings highlight a critical role of LH3 in α1α1α2(IV) biosynthesis and suggest that LH3 pathogenic variants might contribute to Gould syndrome.
Collapse
Affiliation(s)
- Yoshihiro Ishikawa
- Department of Ophthalmology, University of California San Francisco, School of Medicine, California, USA.
| | - Yuki Taga
- Nippi Research Institute of Biomatrix, Ibaraki, Japan
| | - Thibault Coste
- Université Paris Cité, Inserm Neurodiderot, AP-HP Paris, France
| | - Sara F Tufa
- Research Department, Shriners Hospital for Children, Portland, Oregon, USA
| | - Douglas R Keene
- Research Department, Shriners Hospital for Children, Portland, Oregon, USA
| | | | | | - Douglas B Gould
- Department of Ophthalmology, University of California San Francisco, School of Medicine, California, USA; Department Anatomy, Cardiovascular Research Institute, Bakar Aging Research Institute, and Institute for Human Genetics, University of California, San Francisco, California, USA.
| |
Collapse
|
6
|
Zhang W, Hu L, Huang X, Xie D, Wu J, Fu X, Liang D, Huang S. Whole-exome sequencing identified five novel de novo variants in patients with unexplained intellectual disability. J Clin Lab Anal 2022; 36:e24587. [PMID: 35837997 PMCID: PMC9459325 DOI: 10.1002/jcla.24587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/20/2022] [Accepted: 06/25/2022] [Indexed: 11/30/2022] Open
Abstract
Background Intellectual disability (ID) represents a neurodevelopmental disorder, which is characterized by marked defects in the intellectual function and adaptive behavior, with an onset during the developmental period. ID is mainly caused by genetic factors, and it is extremely genetically heterogeneous. This study aims to identify the genetic cause of ID using trio‐WES analysis. Methods We recruited four pediatric patients with unexplained ID from non‐consanguineous families, who presented at the Department of Pediatrics, Guizhou Provincial People's Hospital. Whole‐exome sequencing (WES) and Sanger sequencing validation were performed in the patients and their unaffected parents. Furthermore, conservative analysis and protein structural and functional prediction were performed on the identified pathogenic variants. Results We identified five novel de novo mutations from four known ID‐causing genes in the four included patients, namely COL4A1 (c.2786T>A, p.V929D and c.2797G>A, p.G933S), TBR1 (c.1639_1640insCCCGCAGTCC, p.Y553Sfs*124), CHD7 (c.7013A>T, p.Q2338L), and TUBA1A (c.1350del, p.E450Dfs*34). These mutations were all predicted to be deleterious and were located at highly conserved domains that might affect the structure and function of these proteins. Conclusion Our findings contribute to expanding the mutational spectrum of ID‐related genes and help to deepen the understanding of the genetic causes and heterogeneity of ID.
Collapse
Affiliation(s)
- Wenqiu Zhang
- School of Medicine, Guizhou University, Guiyang, China.,Prenatal Diagnosis Center, Guizhou Provincial People's hospital, Guiyang, China
| | - Li Hu
- Prenatal Diagnosis Center, Guizhou Provincial People's hospital, Guiyang, China
| | - Xinyi Huang
- School of Medical and Life Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Dan Xie
- School of Medicine, Guizhou University, Guiyang, China.,Prenatal Diagnosis Center, Guizhou Provincial People's hospital, Guiyang, China
| | - Jiangfen Wu
- School of Medicine, Guizhou University, Guiyang, China.,Prenatal Diagnosis Center, Guizhou Provincial People's hospital, Guiyang, China
| | - Xiaoling Fu
- Department of Pediatrics, Guizhou Provincial People's hospital, Guiyang, China
| | - Daiyi Liang
- Department of Neurology, Guizhou Provincial People's hospital, Guiyang, China
| | - Shengwen Huang
- School of Medicine, Guizhou University, Guiyang, China.,Prenatal Diagnosis Center, Guizhou Provincial People's hospital, Guiyang, China.,NHC Key Laboratory of Pulmonary Immunological Diseases, Guizhou Provincial People's Hospital, Guiyang, China
| |
Collapse
|
7
|
Gubana F, Christov C, Coste T, Tournier-Lasserve E, Benachi A, Fallet-Bianco C, Encha-Razavi F, Martinovic J. Prenatal Diagnosis of COL4A1 Mutations in Eight Cases: Further Delineation of the Neurohistopathological Phenotype. Pediatr Dev Pathol 2022; 25:435-446. [PMID: 35382634 DOI: 10.1177/10935266221080134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND Increasing number of mutations responsible for vascular lesions, leading to ischemic or hemorrhagic stroke in young adults, has been identified in the recent years. It has been demonstrated in both mice and humans, that mutations in COL4A1 gene promote cerebral hemorrhages. In humans, both adults and children may be affected, and the spectrum has been broadened recently to neonates and fetuses. METHODS We present a cohort of eight COL4A1 mutated fetuses in which cerebral hemorrhages were detected by ultrasound leading to elective terminations of pregnancy. RESULTS Our neuropathological studies demonstrated a strikingly similar pathological pattern, dominated by supra- and infratentorial multifocal hemorrhagic lesions of various abundance and age in the vicinity of enlarged small vessels having a discontinuous wall. This was constantly associated with a spectrum of supratentorial post-ischemic damages of the grey and white matters. Morphometric studies of brain vessels confirmed vascular dilation and hypervascularization in both grey and white matters and severe attenuation of the smooth-muscle actin staining in the white matter. CONCLUSION These observations add to the rare human neuropathological phenotype of COL4A1 mutations. Its recognition is mandatory to enhance the number of tested patients in the future, as well as the genetic counseling of parents.
Collapse
Affiliation(s)
- Francesca Gubana
- Unit of Embryo-Fetal Pathology, AP-HP, 36895Antoine Béclère Hospital, Clamart, France.,Department of Obstetrics and Gynecology, AP-HP, 36895Antoine Béclère Hospital, Paris Saclay University, Clamart, France
| | - Christo Christov
- Department of Histology, CHRU, 571075INSERM U1256, NGERE, Nancy, France
| | - Thibault Coste
- Department of Neurovascular Genetics, AP-HP, 571075St Louis Hospital, Paris, France
| | | | - Alexandra Benachi
- Department of Obstetrics and Gynecology, AP-HP, 36895Antoine Béclère Hospital, Paris Saclay University, Clamart, France
| | | | - Ferechte Encha-Razavi
- Unit of Embryo-Fetal Pathology, AP-HP, 36895Antoine Béclère Hospital, Clamart, France
| | - Jelena Martinovic
- Unit of Embryo-Fetal Pathology, AP-HP, 36895Antoine Béclère Hospital, Clamart, France
| |
Collapse
|
8
|
Mao M, Labelle-Dumais C, Tufa SF, Keene DR, Gould DB. Elevated TGFβ signaling contributes to ocular anterior segment dysgenesis in Col4a1 mutant mice. Matrix Biol 2022; 110:151-173. [PMID: 35525525 PMCID: PMC10410753 DOI: 10.1016/j.matbio.2022.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 04/08/2022] [Accepted: 05/02/2022] [Indexed: 10/18/2022]
Abstract
Ocular anterior segment dysgenesis (ASD) refers to a collection of developmental disorders affecting the anterior structures of the eye. Although a number of genes have been implicated in the etiology of ASD, the underlying pathogenetic mechanisms remain unclear. Mutations in genes encoding collagen type IV alpha 1 (COL4A1) and alpha 2 (COL4A2) cause Gould syndrome, a multi-system disorder that often includes ocular manifestations such as ASD and glaucoma. COL4A1 and COL4A2 are abundant basement membrane proteins that provide structural support to tissues and modulate signaling through interactions with other extracellular matrix proteins, growth factors, and cell surface receptors. In this study, we used a combination of histological, molecular, genetic and pharmacological approaches to demonstrate that altered TGFβ signaling contributes to ASD in mouse models of Gould syndrome. We show that TGFβ signaling was elevated in anterior segments from Col4a1 mutant mice and that genetically reducing TGFβ signaling partially prevented ASD. Notably, we identified distinct roles for TGFβ1 and TGFβ2 in ocular defects observed in Col4a1 mutant mice. Importantly, we show that pharmacologically promoting type IV collagen secretion or reducing TGFβ signaling ameliorated ocular pathology in Col4a1 mutant mice. Overall, our findings demonstrate that altered TGFβ signaling contributes to COL4A1-related ocular dysgenesis and implicate this pathway as a potential therapeutic target for the treatment of Gould syndrome.
Collapse
Affiliation(s)
- Mao Mao
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, United States
| | - Cassandre Labelle-Dumais
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, United States
| | - Sara F Tufa
- Shriners Children's, Micro-Imaging Center, Portland, Oregon 97239, United States
| | - Douglas R Keene
- Shriners Children's, Micro-Imaging Center, Portland, Oregon 97239, United States
| | - Douglas B Gould
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, United States; Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, United States; Institute for Human Genetics, University of California, San Francisco, San Francisco, CA 94143, United States; Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, United States; Bakar Aging Research Institute, University of California, San Francisco, San Francisco, CA 94143, United States.
| |
Collapse
|
9
|
Zhang X, Wang D, Dongye M, Zhu Y, Chen C, Wang R, Long E, Liu Z, Wu X, Lin D, Chen J, Lin Z, Wang J, Li W, Li Y, Li D, Lin H. Loss-of-function mutations in FREM2 disrupt eye morphogenesis. Exp Eye Res 2019; 181:302-312. [PMID: 30802441 DOI: 10.1016/j.exer.2019.02.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/30/2019] [Accepted: 02/17/2019] [Indexed: 10/27/2022]
Abstract
Cryptophthalmos is a rare congenital disorder characterized by ocular dysplasia with eyelid malformation. Complete cryptophthalmos is characterized by the presence of continuous skin from the forehead over the eyes and onto the cheek, along with complete fusion of the eyelids. In the present study, we characterized the clinical manifestations of three patients with isolated bilateral cryptophthalmos. These patients shared the same c.6499C > T missense mutation in the FRAS1-related extracellular matrix protein 2 (FREM2) gene, while each individual presented an additional nonsense mutation in the same gene (Patient #1, c.2206C > T; Patient #2, c.5309G > A; and Patient #3, c.4063C > T). Then, we used CRISPR/Cas9 to generate mice carrying Frem2R725X/R2156W compound heterozygous mutations, and showed that these mice recapitulated the human isolated cryptophthalmos phenotype. We detected FREM2 expression in the outer plexiform layer of the retina for the first time in the cryptophthalmic eyes, and the levels were comparable to the wild-type mice. Moreover, a set of different expressed genes that may contribute secondarily to the phenotypes were identified by performing RNA sequencing (RNA-seq) of the fetal Frem2 mutant mice. Our findings extend the spectrum of FREM2 mutations, and provide insights into opportunities for the prenatal diagnosis of isolated cryptophthalmos. Furthermore, our work highlights the importance of the FREM2 protein during the development of eyelids and the anterior segment of the eyeballs, establishes a suitable animal model for studying epithelial reopening during eyelid development and serves as a valuable reference for further mechanistic studies of the pathogenesis of isolated cryptophthalmos.
Collapse
Affiliation(s)
- Xiayin Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China
| | - Dongni Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China
| | - Meimei Dongye
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China
| | - Yi Zhu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China; Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Chuan Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China; Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Ruixin Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China
| | - Erping Long
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China
| | - Zhenzhen Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China
| | - Xiaohang Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China
| | - Duoru Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China
| | - Jingjing Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China
| | - Zhuoling Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China
| | - Jinghui Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China
| | - Wangting Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China
| | - Yang Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Key Laboratory of Ophthalmology and Visual Science, Beijing, 100730, China
| | - Dongmei Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Key Laboratory of Ophthalmology and Visual Science, Beijing, 100730, China
| | - Haotian Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China.
| |
Collapse
|
10
|
Jones FE, Murray LS, McNeilly S, Dean A, Aman A, Lu Y, Nikolova N, Malomgré R, Horsburgh K, Holmes WM, Kadler KE, Van Agtmael T. 4-Sodium phenyl butyric acid has both efficacy and counter-indicative effects in the treatment of Col4a1 disease. Hum Mol Genet 2019; 28:628-638. [PMID: 30351356 PMCID: PMC6360271 DOI: 10.1093/hmg/ddy369] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 10/11/2018] [Indexed: 12/22/2022] Open
Abstract
Mutations in the collagen genes COL4A1 and COL4A2 cause Mendelian eye, kidney and cerebrovascular disease including intracerebral haemorrhage (ICH), and common collagen IV variants are a risk factor for sporadic ICH. COL4A1 and COL4A2 mutations cause endoplasmic reticulum (ER) stress and basement membrane (BM) defects, and recent data suggest an association of ER stress with ICH due to a COL4A2 mutation. However, the potential of ER stress as a therapeutic target for the multi-systemic COL4A1 pathologies remains unclear. We performed a preventative oral treatment of Col4a1 mutant mice with the chemical chaperone phenyl butyric acid (PBA), which reduced adult ICH. Importantly, treatment of adult mice with the established disease also reduced ICH. However, PBA treatment did not alter eye and kidney defects, establishing tissue-specific outcomes of targeting Col4a1-derived ER stress, and therefore this treatment may not be applicable for patients with eye and renal disease. While PBA treatment reduced ER stress and increased collagen IV incorporation into BMs, the persistence of defects in BM structure and reduced ability of the BM to withstand mechanical stress indicate that PBA may be counter-indicative for pathologies caused by matrix defects. These data establish that treatment for COL4A1 disease requires a multipronged treatment approach that restores both ER homeostasis and matrix defects. Alleviating ER stress is a valid therapeutic target for preventing and treating established adult ICH, but collagen IV patients will require stratification based on their clinical presentation and mechanism of their mutations.
Collapse
Affiliation(s)
- Frances E Jones
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Lydia S Murray
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Sarah McNeilly
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Afshan Dean
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Alisha Aman
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Yinhui Lu
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
| | - Nija Nikolova
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Ruben Malomgré
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Karen Horsburgh
- Centre for Discovery Brain Sciences, Medical School, University of Edinburgh, Edinburgh, UK
| | - William M Holmes
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Karl E Kadler
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
| | - Tom Van Agtmael
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| |
Collapse
|
11
|
Rausch RL, Libby RT, Kiernan AE. Ciliary margin-derived BMP4 does not have a major role in ocular development. PLoS One 2018; 13:e0197048. [PMID: 29738572 PMCID: PMC5940228 DOI: 10.1371/journal.pone.0197048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 04/25/2018] [Indexed: 11/18/2022] Open
Abstract
Heterozygous Bmp4 mutations in humans and mice cause severe ocular anterior segment dysgenesis (ASD). Abnormalities include pupil displacement, corneal opacity, iridocorneal adhesions, and variable intraocular pressure, as well as some retinal and vascular defects. It is presently not known what source of BMP4 is responsible for these defects, as BMP4 is expressed in several developing ocular and surrounding tissues. In particular, BMP4 is expressed in the ciliary margins of the optic cup which give rise to anterior segment structures such as the ciliary body and iris, making it a good candidate for the required source of BMP4 for anterior segment development. Here, we test whether ciliary margin-derived BMP4 is required for ocular development using two different conditional knockout approaches. In addition, we compared the conditional deletion phenotypes with Bmp4 heterozygous null mice. Morphological, molecular, and functional assays were performed on adult mutant mice, including histology, immunohistochemistry, in vivo imaging, and intraocular pressure measurements. Surprisingly, in contrast to Bmp4 heterozygous mutants, our analyses revealed that the anterior and posterior segments of Bmp4 conditional knockouts developed normally. These results indicate that ciliary margin-derived BMP4 does not have a major role in ocular development, although subtle alterations could not be ruled out. Furthermore, we demonstrated that the anterior and posterior phenotypes observed in Bmp4 heterozygous animals showed a strong propensity to co-occur, suggesting a common, non-cell autonomous source for these defects.
Collapse
Affiliation(s)
- Rebecca L. Rausch
- Neuroscience Graduate Program, University of Rochester Medical Center, Rochester, NY, United States of America
- Department of Ophthalmology, University of Rochester Medical Center, Rochester, NY, United States of America
- Center for Visual Sciences, University of Rochester, Rochester, NY, United States of America
| | - Richard T. Libby
- Department of Ophthalmology, University of Rochester Medical Center, Rochester, NY, United States of America
- Center for Visual Sciences, University of Rochester, Rochester, NY, United States of America
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY, United States of America
| | - Amy E. Kiernan
- Department of Ophthalmology, University of Rochester Medical Center, Rochester, NY, United States of America
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY, United States of America
| |
Collapse
|
12
|
Novel COL4A1 mutation in a fetus with early prenatal onset of schizencephaly. Hum Genome Var 2018; 5:4. [PMID: 29760938 PMCID: PMC5938052 DOI: 10.1038/s41439-018-0005-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 02/26/2018] [Accepted: 03/13/2018] [Indexed: 12/21/2022] Open
Abstract
Porencephaly and schizencephaly are congenital brain disorders that can be caused by COL4A1 mutations, though the underlying mechanism and developmental processes are poorly understood. Here, we report a patient with schizencephaly, detected by fetal ultrasonography and fetal magnetic resonance imaging, with a de novo novel mutation in COL4A1 (c.2645_2646delinsAA, p.Gly882Glu). Our results suggest that the onset of damage that potentially results in schizencephaly occurs mid-pregnancy.
Collapse
|
13
|
Rausch RL, Libby RT, Kiernan AE. Trabecular meshwork morphogenesis: A comparative analysis of wildtype and anterior segment dysgenesis mouse models. Exp Eye Res 2018; 170:81-91. [PMID: 29452107 DOI: 10.1016/j.exer.2018.02.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 01/12/2018] [Accepted: 02/12/2018] [Indexed: 10/18/2022]
Abstract
The trabecular meshwork (TM), a tissue residing in the iridocorneal angle of the eye, is the primary site of aqueous humor outflow and often develops abnormally in children with anterior segment dysgenesis (ASD). However, the cellular mechanisms underlying both normal and pathophysiological TM formation are poorly understood. Here, we improve the characterization of TM development via morphological and molecular analyses. We first assessed the TM of wild-type C57BL/6J mice at multiple time points throughout development (E15.5-P21). The morphology of TM cells, rate of cell division, presence of apoptotic cell death, and age of onset of an established TM marker (αSMA) were each assessed in the developing iridocorneal angle. We discovered that TM cells are identifiable histologically at P1, which coincided with both the onset of αSMA expression and a significant decrease in TM precursor cell proliferation. Significant apoptotic cell death was not detected during TM development. These findings were then used to assess two mouse models of ASD. Jag1 and Bmp4 heterozygous null mice display ASD phenotypes in the adult, including TM hypoplasia and corneal adherence to the iris. We further discovered that both mutants exhibited similar patterns of developmental TM dysgenesis at P1, P5, and P10. Our data indicate that P1 is an important time point in TM development and that TM dysgenesis in Jag1 and Bmp4 heterozygous null mice likely results from impaired TM cell migration and/or differentiation.
Collapse
Affiliation(s)
- Rebecca L Rausch
- Neuroscience Graduate Program, University of Rochester Medical Center, Rochester, NY 14642, USA; Department of Ophthalmology, University of Rochester Medical Center, Rochester, NY 14642, USA; Center for Visual Sciences, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Richard T Libby
- Department of Ophthalmology, University of Rochester Medical Center, Rochester, NY 14642, USA; Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642, USA; Center for Visual Sciences, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Amy E Kiernan
- Department of Ophthalmology, University of Rochester Medical Center, Rochester, NY 14642, USA; Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642, USA.
| |
Collapse
|
14
|
Hägglund AC, Jones I, Carlsson L. A novel mouse model of anterior segment dysgenesis (ASD): conditional deletion of Tsc1 disrupts ciliary body and iris development. Dis Model Mech 2017; 10:245-257. [PMID: 28250050 PMCID: PMC5374326 DOI: 10.1242/dmm.028605] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 01/05/2017] [Indexed: 12/22/2022] Open
Abstract
Development of the cornea, lens, ciliary body and iris within the anterior segment of the eye involves coordinated interaction between cells originating from the ciliary margin of the optic cup, the overlying periocular mesenchyme and the lens epithelium. Anterior segment dysgenesis (ASD) encompasses a spectrum of developmental syndromes that affect these anterior segment tissues. ASD conditions arise as a result of dominantly inherited genetic mutations and result in both ocular-specific and systemic forms of dysgenesis that are best exemplified by aniridia and Axenfeld-Rieger syndrome, respectively. Extensive clinical overlap in disease presentation amongst ASD syndromes creates challenges for correct diagnosis and classification. The use of animal models has therefore proved to be a robust approach for unravelling this complex genotypic and phenotypic heterogeneity. However, despite these successes, it is clear that additional genes that underlie several ASD syndromes remain unidentified. Here, we report the characterisation of a novel mouse model of ASD. Conditional deletion of Tsc1 during eye development leads to a premature upregulation of mTORC1 activity within the ciliary margin, periocular mesenchyme and lens epithelium. This aberrant mTORC1 signalling within the ciliary margin in particular leads to a reduction in the number of cells that express Pax6, Bmp4 and Msx1 Sustained mTORC1 signalling also induces a decrease in ciliary margin progenitor cell proliferation and a consequent failure of ciliary body and iris development in postnatal animals. Our study therefore identifies Tsc1 as a novel candidate ASD gene. Furthermore, the Tsc1-ablated mouse model also provides a valuable resource for future studies concerning the molecular mechanisms underlying ASD and acts as a platform for evaluating therapeutic approaches for the treatment of visual disorders.
Collapse
Affiliation(s)
- Anna-Carin Hägglund
- Umeå Center for Molecular Medicine (UCMM), Umeå University, Umeå 901 87, Sweden
| | - Iwan Jones
- Umeå Center for Molecular Medicine (UCMM), Umeå University, Umeå 901 87, Sweden
| | - Leif Carlsson
- Umeå Center for Molecular Medicine (UCMM), Umeå University, Umeå 901 87, Sweden
| |
Collapse
|
15
|
Meyer KJ, Anderson MG. Genetic modifiers as relevant biological variables of eye disorders. Hum Mol Genet 2017; 26:R58-R67. [PMID: 28482014 DOI: 10.1093/hmg/ddx180] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 05/05/2017] [Indexed: 12/19/2022] Open
Abstract
From early in the study of mammalian genetics, it was clear that modifiers can have a striking influence on phenotypes. Today, several modifiers have now been studied in enough detail to allow a glimpse of how they function and influence our perspective of disease. With respect to diseases of the eye, some modifiers are an important source of phenotypic variation that can elucidate how genes function in networks to collectively shape ocular anatomy and physiology, thus influencing our understanding of basic biology. Other modifiers represent an opportunity for new therapeutic targets, whose manipulation could be used to mitigate ophthalmic disease. Here, we review progress in the study of genetic modifiers of eye disorders, with examples from mice and humans that together illustrate the ubiquitous nature of genetic modifiers and why they are relevant biological variables in experimental design. Special emphasis is given to ophthalmic modifiers in mice, especially those relevant to selection of genetic background and those that might inadvertently be a source of experimental variability. These modifiers are capable of influencing interpretations of many experiments using targeted genome manipulations such as knockouts or transgenics. Whereas there are fewer examples of modifiers of eye disorders in humans with a molecular identification, there is ample evidence that they exist and should be considered as a relevant biological variable in human genetic studies as well.
Collapse
Affiliation(s)
- Kacie J Meyer
- Department of Molecular Physiology and Biophysics.,Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Michael G Anderson
- Department of Molecular Physiology and Biophysics.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.,Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA.,Center for Prevention and Treatment of Visual Loss, Iowa City Veterans Administration Medical Center, Iowa City, IA 52242, USA
| |
Collapse
|
16
|
Mao M, Kiss M, Ou Y, Gould DB. Genetic dissection of anterior segment dysgenesis caused by a Col4a1 mutation in mouse. Dis Model Mech 2017; 10:475-485. [PMID: 28237965 PMCID: PMC5399567 DOI: 10.1242/dmm.027888] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 02/20/2017] [Indexed: 12/21/2022] Open
Abstract
Ocular anterior segment dysgenesis (ASD) describes a spectrum of clinically and genetically heterogeneous congenital disorders affecting anterior structures that often lead to impaired vision. More importantly, 50-75% of patients with ASD develop early onset and aggressive glaucoma. Although several genes have been implicated in the etiology of ASD, the underlying mechanisms remain elusive. Type IV collagen alpha 1 (COL4A1) is an extracellular matrix protein and a critical component of nearly all basement membranes. COL4A1 mutations cause multi-system disorders in patients, including ASD (congenital cataracts, Axenfeld-Rieger's anomaly, Peter's anomaly and microphthalmia) and congenital or juvenile glaucoma. Here, we use a conditional Col4a1 mutation in mice to determine the location and timing of pathogenic events underlying COL4A1-related ocular dysgenesis. Our results suggest that selective expression of the Col4a1 mutation in neural crest cells and their derivatives is not sufficient to cause ocular dysgenesis and that selective expression of the Col4a1 mutation in vascular endothelial cells can lead to mild ASD and optic nerve hypoplasia but only on a sensitized background. In contrast, lens-specific expression of the conditional Col4a1 mutant allele led to cataracts, mild ASD and optic nerve hypoplasia, and age-related intraocular pressure dysregulation and optic nerve damage. Finally, ubiquitous expression of the conditional Col4a1 mutation at distinct developmental stages suggests that pathogenesis takes place before E12.5. Our results show that the lens and possibly vasculature play important roles in Col4a1-related ASD and that the pathogenic events occur at mid-embryogenesis in mice, during early stages of ocular development. Summary: Key pathogenic events in anterior segment dysgenesis, a congenital ocular disease with complex etiology, are recapitulated in a mouse model of Col4a1-related ASD.
Collapse
Affiliation(s)
- Mao Mao
- Department of Ophthalmology, Institute for Human Genetics, UCSF School of Medicine, San Francisco, CA 94143, USA
| | - Márton Kiss
- Department of Genetics, University of Szeged, Középfasor 52, Szeged H-6726, Hungary
| | - Yvonne Ou
- Department of Ophthalmology, Institute for Human Genetics, UCSF School of Medicine, San Francisco, CA 94143, USA
| | - Douglas B Gould
- Department of Ophthalmology, Institute for Human Genetics, UCSF School of Medicine, San Francisco, CA 94143, USA .,Department of Anatomy, Institute for Human Genetics, UCSF School of Medicine, San Francisco, CA 94143, USA
| |
Collapse
|
17
|
Jeanne M, Gould DB. Genotype-phenotype correlations in pathology caused by collagen type IV alpha 1 and 2 mutations. Matrix Biol 2016; 57-58:29-44. [PMID: 27794444 DOI: 10.1016/j.matbio.2016.10.003] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 10/10/2016] [Indexed: 12/11/2022]
Abstract
COL4A1 and COL4A2 are extracellular matrix proteins that form heterotrimers and are present in nearly all basement membranes in every organ. In the past decade, COL4A1 and COL4A2 mutations have been identified to cause a multi-system disorder for which penetrance and severity of constituent phenotypes can greatly vary. Here, we compare the outcomes of more than 100 mutations identified in patients and data from a murine allelic series to explore the presence of genotype-phenotype correlations - many of which are shared among other types of collagen. We find that there is a frequency bias for COL4A1 over COL4A2 mutations and that glycine (Gly) substitutions within the triple helical domain are the most common class of mutations. Glycine is most often replaced by a charged amino acid, however the position of the mutation, and not the properties of the substituting amino acid, appears to have a greater influence on disease severity. Moreover, the impact of position is not straightforward. Observations from a murine allelic series suggest that mutations in the NC1 domain may result in relatively mild phenotypes via a 'quantitative' mechanism similar to other types of collagens, however, this effect was not apparent in human reports. Importantly, other position-dependent effects had differential impacts depending on the phenotype of interest. For example, the severity of cerebrovascular disease correlated with an amino-to-carboxy severity gradient for triple-helical glycine substitutions whereas the penetrance and severity of myopathy and nephropathy appear to involve a functional sub-domain(s). Greater understanding of genotype-phenotype correlations and the interaction of consequences of different mutations will be important for patient prognosis and care and for developing mechanism-based therapeutics to treat individual components of this emerging syndrome.
Collapse
Affiliation(s)
- Marion Jeanne
- Genentech Inc, 1 DNA Way, South San Francisco, CA 94080, USA.
| | - Douglas B Gould
- Department of Ophthalmology, Department of Anatomy, Institute for Human Genetics, UCSF School of Medicine, San Francisco, CA 94143, USA.
| |
Collapse
|
18
|
Col4a1 mutations cause progressive retinal neovascular defects and retinopathy. Sci Rep 2016; 6:18602. [PMID: 26813606 PMCID: PMC4728690 DOI: 10.1038/srep18602] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 11/23/2015] [Indexed: 02/07/2023] Open
Abstract
Mutations in collagen, type IV, alpha 1 (COL4A1), a major component of basement membranes, cause multisystem disorders in humans and mice. In the eye, these include anterior segment dysgenesis, optic nerve hypoplasia and retinal vascular tortuosity. Here we investigate the retinal pathology in mice carrying dominant-negative Col4a1 mutations. To this end, we examined retinas longitudinally in vivo using fluorescein angiography, funduscopy and optical coherence tomography. We assessed retinal function by electroretinography and studied the retinal ultrastructural pathology. Retinal examinations revealed serous chorioretinopathy, retinal hemorrhages, fibrosis or signs of pathogenic angiogenesis with chorioretinal anastomosis in up to approximately 90% of Col4a1 mutant eyes depending on age and the specific mutation. To identify the cell-type responsible for pathogenesis we generated a conditional Col4a1 mutation and determined that primary vascular defects underlie Col4a1-associated retinopathy. We also found focal activation of Müller cells and increased expression of pro-angiogenic factors in retinas from Col4a1(+/Δex41)mice. Together, our findings suggest that patients with COL4A1 and COL4A2 mutations may be at elevated risk of retinal hemorrhages and that retinal examinations may be useful for identifying patients with COL4A1 and COL4A2 mutations who are also at elevated risk of hemorrhagic strokes.
Collapse
|