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Tory K. The dominant findings of a recessive man: from Mendel's kid pea to kidney. Pediatr Nephrol 2024; 39:2049-2059. [PMID: 38051388 PMCID: PMC11147900 DOI: 10.1007/s00467-023-06238-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 11/07/2023] [Accepted: 11/15/2023] [Indexed: 12/07/2023]
Abstract
The research of Mendel, born two centuries ago, still has many direct implications for our everyday clinical work. He introduced the terms "dominant" and "recessive" characters and determined their 3:1 ratio in the offspring of heterozygous "hybrid" plants. This distribution allowed calculation of the number of the phenotype-determining "elements," i.e., the alleles, and has been used ever since to prove the monogenic origin of a disorder. The Mendelian inheritance of monogenic kidney disorders is still of great help in distinguishing them from those with multifactorial origin in clinical practice. Inheritance of most monogenic kidney disorders fits to Mendel's observations: the equal contribution of the two parents and the complete penetrance or the direct correlation between the frequency of the recessive character and the degree of inbreeding. Nevertheless, beyond the truth of these basic concepts, several observations have expanded their genetic characteristics. The extreme genetic heterogeneity, the pleiotropy of the causal genes and the role of modifiers in ciliopathies, the digenic inheritance and parental imprinting in some tubulopathies, and the incomplete penetrance and eventual interallelic interactions in podocytopathies, reflect this expansion. For all these reasons, the transmission pattern in a natural setting may depend not only on the "character" but also on the causal gene and the variant. Mendel's passion for research combined with his modest personality and meticulous approach can still serve as an example in the work required to understand the non-Mendelian universe of genetics.
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Affiliation(s)
- Kálmán Tory
- MTA-SE Lendület Nephrogenetic Laboratory, Hungarian Academy of Sciences, Budapest, Hungary.
- Pediatric Center, MTA Center of Excellence, Semmelweis University, Budapest, Hungary.
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2
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Malvasi M, Casillo L, Avogaro F, Abbouda A, Vingolo EM. Gene Therapy in Hereditary Retinal Dystrophies: The Usefulness of Diagnostic Tools in Candidate Patient Selections. Int J Mol Sci 2023; 24:13756. [PMID: 37762059 PMCID: PMC10531171 DOI: 10.3390/ijms241813756] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/24/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
PURPOSE Gene therapy actually seems to have promising results in the treatment of Leber Congenital Amaurosis and some different inherited retinal diseases (IRDs); the primary goal of this strategy is to change gene defects with a wild-type gene without defects in a DNA sequence to achieve partial recovery of the photoreceptor function and, consequently, partially restore lost retinal functions. This approach led to the introduction of a new drug (voretigene neparvovec-rzyl) for replacement of the RPE65 gene in patients affected by Leber Congenital Amaurosis (LCA); however, the treatment results are inconstant and with variable long-lasting effects due to a lack of correctly evaluating the anatomical and functional conditions of residual photoreceptors. These variabilities may also be related to host immunoreactive reactions towards the Adenovirus-associated vector. A broad spectrum of retinal dystrophies frequently generates doubt as to whether the disease or the patient is a good candidate for a successful gene treatment, because, very often, different diseases share similar genetic characteristics, causing an inconstant genotype/phenotype correlation between clinical characteristics also within the same family. For example, mutations on the RPE65 gene cause Leber Congenital Amaurosis (LCA) but also some forms of Retinitis Pigmentosa (RP), Bardet Biedl Syndrome (BBS), Congenital Stationary Night Blindness (CSNB) and Usher syndrome (USH), with a very wide spectrum of clinical manifestations. These confusing elements are due to the different pathways in which the product protein (retinoid isomer-hydrolase) is involved and, consequently, the overlapping metabolism in retinal function. Considering this point and the cost of the drug (over USD one hundred thousand), it would be mandatory to follow guidelines or algorithms to assess the best-fitting disease and candidate patients to maximize the output. Unfortunately, at the moment, there are no suggestions regarding who to treat with gene therapy. Moreover, gene therapy might be helpful in other forms of inherited retinal dystrophies, with more frequent incidence of the disease and better functional conditions (actually, gene therapy is proposed only for patients with poor vision, considering possible side effects due to the treatment procedures), in which this approach leads to better function and, hopefully, visual restoration. But, in this view, who might be a disease candidate or patient to undergo gene therapy, in relationship to the onset of clinical trials for several different forms of IRD? Further, what is the gold standard for tests able to correctly select the patient? Our work aims to evaluate clinical considerations on instrumental morphofunctional tests to assess candidate subjects for treatment and correlate them with clinical and genetic defect analysis that, often, is not correspondent. We try to define which parameters are an essential and indispensable part of the clinical rationale to select patients with IRDs for gene therapy. This review will describe a series of models used to characterize retinal morphology and function from tests, such as optical coherence tomography (OCT) and electrophysiological evaluation (ERG), and its evaluation as a primary outcome in clinical trials. A secondary aim is to propose an ancillary clinical classification of IRDs and their accessibility based on gene therapy's current state of the art. MATERIAL AND METHODS OCT, ERG, and visual field examinations were performed in different forms of IRDs, classified based on clinical and retinal conditions; compared to the gene defect classification, we utilized a diagnostic algorithm for the clinical classification based on morphofunctional information of the retina of patients, which could significantly improve diagnostic accuracy and, consequently, help the ophthalmologist to make a correct diagnosis to achieve optimal clinical results. These considerations are very helpful in selecting IRD patients who might respond to gene therapy with possible therapeutic success and filter out those in which treatment has a lower chance or no chance of positive results due to bad retinal conditions, avoiding time-consuming patient management with unsatisfactory results.
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Affiliation(s)
- Mariaelena Malvasi
- Department of Sense Organs, Faculty of Medicine and Dentistry, Sapienza University of Rome, 00185 Rome, Italy; (L.C.); (E.M.V.)
| | - Lorenzo Casillo
- Department of Sense Organs, Faculty of Medicine and Dentistry, Sapienza University of Rome, 00185 Rome, Italy; (L.C.); (E.M.V.)
| | - Filippo Avogaro
- Department of Sense Organs, Faculty of Medicine and Dentistry, Sapienza University of Rome, 00185 Rome, Italy; (L.C.); (E.M.V.)
| | - Alessandro Abbouda
- Department of Ophthalmology, Fiorini Hospital Terracina AUSL, 04019 Terracina, Italy
| | - Enzo Maria Vingolo
- Department of Sense Organs, Faculty of Medicine and Dentistry, Sapienza University of Rome, 00185 Rome, Italy; (L.C.); (E.M.V.)
- Department of Ophthalmology, Fiorini Hospital Terracina AUSL, 04019 Terracina, Italy
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3
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Leggatt GP, Seaby EG, Veighey K, Gast C, Gilbert RD, Ennis S. A Role for Genetic Modifiers in Tubulointerstitial Kidney Diseases. Genes (Basel) 2023; 14:1582. [PMID: 37628633 PMCID: PMC10454709 DOI: 10.3390/genes14081582] [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: 07/17/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 08/27/2023] Open
Abstract
With the increased availability of genomic sequencing technologies, the molecular bases for kidney diseases such as nephronophthisis and mitochondrially inherited and autosomal-dominant tubulointerstitial kidney diseases (ADTKD) has become increasingly apparent. These tubulointerstitial kidney diseases (TKD) are monogenic diseases of the tubulointerstitium and result in interstitial fibrosis and tubular atrophy (IF/TA). However, monogenic inheritance alone does not adequately explain the highly variable onset of kidney failure and extra-renal manifestations. Phenotypes vary considerably between individuals harbouring the same pathogenic variant in the same putative monogenic gene, even within families sharing common environmental factors. While the extreme end of the disease spectrum may have dramatic syndromic manifestations typically diagnosed in childhood, many patients present a more subtle phenotype with little to differentiate them from many other common forms of non-proteinuric chronic kidney disease (CKD). This review summarises the expanding repertoire of genes underpinning TKD and their known phenotypic manifestations. Furthermore, we collate the growing evidence for a role of modifier genes and discuss the extent to which these data bridge the historical gap between apparently rare monogenic TKD and polygenic non-proteinuric CKD (excluding polycystic kidney disease).
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Affiliation(s)
- Gary P. Leggatt
- Human Genetics & Genomic Medicine, University of Southampton, Southampton SO16 6YD, UK; (E.G.S.); (K.V.); (C.G.); (R.D.G.); (S.E.)
- Wessex Kidney Centre, Queen Alexandra Hospital, Portsmouth Hospitals NHS Trust, Portsmouth PO6 3LY, UK
- Renal Department, University Hospital Southampton, Southampton SO16 6YD, UK
| | - Eleanor G. Seaby
- Human Genetics & Genomic Medicine, University of Southampton, Southampton SO16 6YD, UK; (E.G.S.); (K.V.); (C.G.); (R.D.G.); (S.E.)
| | - Kristin Veighey
- Human Genetics & Genomic Medicine, University of Southampton, Southampton SO16 6YD, UK; (E.G.S.); (K.V.); (C.G.); (R.D.G.); (S.E.)
- Renal Department, University Hospital Southampton, Southampton SO16 6YD, UK
| | - Christine Gast
- Human Genetics & Genomic Medicine, University of Southampton, Southampton SO16 6YD, UK; (E.G.S.); (K.V.); (C.G.); (R.D.G.); (S.E.)
- Wessex Kidney Centre, Queen Alexandra Hospital, Portsmouth Hospitals NHS Trust, Portsmouth PO6 3LY, UK
| | - Rodney D. Gilbert
- Human Genetics & Genomic Medicine, University of Southampton, Southampton SO16 6YD, UK; (E.G.S.); (K.V.); (C.G.); (R.D.G.); (S.E.)
- Department of Paediatric Nephrology, Southampton Children’s Hospital, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
| | - Sarah Ennis
- Human Genetics & Genomic Medicine, University of Southampton, Southampton SO16 6YD, UK; (E.G.S.); (K.V.); (C.G.); (R.D.G.); (S.E.)
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Petzold F, Billot K, Chen X, Henry C, Filhol E, Martin Y, Avramescu M, Douillet M, Morinière V, Krug P, Jeanpierre C, Tory K, Boyer O, Burgun A, Servais A, Salomon R, Benmerah A, Heidet L, Garcelon N, Antignac C, Zaidan M, Saunier S. The genetic landscape and clinical spectrum of nephronophthisis and related ciliopathies. Kidney Int 2023:S0085-2538(23)00377-0. [PMID: 37230223 DOI: 10.1016/j.kint.2023.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 04/26/2023] [Accepted: 05/05/2023] [Indexed: 05/27/2023]
Abstract
Nephronophthisis (NPH) is an autosomal-recessive ciliopathy representing one of the most frequent causes of kidney failure in childhood characterized by a broad clinical and genetic heterogeneity. Applied to one of the worldwide largest cohorts of patients with NPH, genetic analysis encompassing targeted and whole exome sequencing identified disease-causing variants in 600 patients from 496 families with a detection rate of 71%. Of 788 pathogenic variants, 40 known ciliopathy genes were identified. However, the majority of patients (53%) bore biallelic pathogenic variants in NPHP1. NPH-causing gene alterations affected all ciliary modules defined by structural and/or functional subdomains. Seventy six percent of these patients had progressed to kidney failure, of which 18% had an infantile form (under five years) and harbored variants affecting the Inversin compartment or intraflagellar transport complex A. Forty eight percent of patients showed a juvenile (5-15 years) and 34% a late-onset disease (over 15 years), the latter mostly carrying variants belonging to the Transition Zone module. Furthermore, while more than 85% of patients with an infantile form presented with extra-kidney manifestations, it only concerned half of juvenile and late onset cases. Eye involvement represented a predominant feature, followed by cerebellar hypoplasia and other brain abnormalities, liver and skeletal defects. The phenotypic variability were in a large part associated with mutation types, genes and corresponding ciliary modules with hypomorphic variants in ciliary genes playing a role in early steps of ciliogenesis associated with juvenile-to-late onset NPH forms. Thus, our data confirm a considerable proportion of late-onset NPH suggesting an underdiagnosis in adult chronic kidney disease.
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Affiliation(s)
- Friederike Petzold
- Laboratory of Hereditary Kidney Diseases, Université de Paris, Imagine Institute, INSERM UMR 1163, Paris, France; Division of Nephrology, Department of Endocrinology, Nephrology, and Rheumatology, University Hospital Leipzig, Leipzig, Germany
| | - Katy Billot
- Laboratory of Hereditary Kidney Diseases, Université de Paris, Imagine Institute, INSERM UMR 1163, Paris, France
| | - Xiaoyi Chen
- Université de Paris, Imagine Institute, Data Science Platform, INSERM UMR 1163, Paris, France; Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France
| | - Charline Henry
- Laboratory of Hereditary Kidney Diseases, Université de Paris, Imagine Institute, INSERM UMR 1163, Paris, France
| | - Emilie Filhol
- Laboratory of Hereditary Kidney Diseases, Université de Paris, Imagine Institute, INSERM UMR 1163, Paris, France
| | - Yoann Martin
- Laboratory of Hereditary Kidney Diseases, Université de Paris, Imagine Institute, INSERM UMR 1163, Paris, France
| | - Marina Avramescu
- Laboratory of Hereditary Kidney Diseases, Université de Paris, Imagine Institute, INSERM UMR 1163, Paris, France; Department of Pediatry, Necker Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Maxime Douillet
- Université de Paris, Imagine Institute, Data Science Platform, INSERM UMR 1163, Paris, France; Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France
| | - Vincent Morinière
- APHP, Génétique moléculaire, Hôpital universitaire Necker-Enfants malades, Paris, France
| | - Pauline Krug
- Laboratory of Hereditary Kidney Diseases, Université de Paris, Imagine Institute, INSERM UMR 1163, Paris, France; Department of Pediatry, Necker Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Cécile Jeanpierre
- Laboratory of Hereditary Kidney Diseases, Université de Paris, Imagine Institute, INSERM UMR 1163, Paris, France
| | - Kalman Tory
- Ist Department of Pediatrics, Semmelweis University, 1083 Budapest, Hungary
| | - Olivia Boyer
- Department of Pediatry, Necker Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France; Nephrology and Transplantation Department, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, APHP, Université de Paris, France
| | - Anita Burgun
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France; Hôpital Necker-Enfants Malades, Department of Medical Informatics, AP-HP, Paris, France; PaRis Artificial Intelligence Research InstitutE (PRAIRIE), France
| | - Aude Servais
- Nephrology and Transplantation Department, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, APHP, Université de Paris, France
| | - Remi Salomon
- Laboratory of Hereditary Kidney Diseases, Université de Paris, Imagine Institute, INSERM UMR 1163, Paris, France; Department of Pediatry, Necker Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France; Université de Paris, Paris, France
| | - Alexandre Benmerah
- Laboratory of Hereditary Kidney Diseases, Université de Paris, Imagine Institute, INSERM UMR 1163, Paris, France
| | - Laurence Heidet
- Laboratory of Hereditary Kidney Diseases, Université de Paris, Imagine Institute, INSERM UMR 1163, Paris, France; Department of Pediatry, Necker Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France; Nephrology and Transplantation Department, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, APHP, Université de Paris, France
| | - Nicolas Garcelon
- Université de Paris, Imagine Institute, Data Science Platform, INSERM UMR 1163, Paris, France; Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France
| | - Corinne Antignac
- Laboratory of Hereditary Kidney Diseases, Université de Paris, Imagine Institute, INSERM UMR 1163, Paris, France
| | - Mohamad Zaidan
- Assistance Publique des Hôpitaux de Paris (AP-HP), Université Paris-Saclay, Hôpital de Bicêtre, Service de Néphrologie et Transplantation, Le Kremlin-Bicêtre, France; Centre de Compétence Maladies Rares « Syndrome Néphrotique Idiopathique », Hôpital de Bicêtre, Le Kremlin-Bicêtre, France
| | - Sophie Saunier
- Laboratory of Hereditary Kidney Diseases, Université de Paris, Imagine Institute, INSERM UMR 1163, Paris, France.
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Cellular and Molecular Mechanisms of Pathogenesis Underlying Inherited Retinal Dystrophies. Biomolecules 2023; 13:biom13020271. [PMID: 36830640 PMCID: PMC9953031 DOI: 10.3390/biom13020271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/23/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Inherited retinal dystrophies (IRDs) are congenital retinal degenerative diseases that have various inheritance patterns, including dominant, recessive, X-linked, and mitochondrial. These diseases are most often the result of defects in rod and/or cone photoreceptor and retinal pigment epithelium function, development, or both. The genes associated with these diseases, when mutated, produce altered protein products that have downstream effects in pathways critical to vision, including phototransduction, the visual cycle, photoreceptor development, cellular respiration, and retinal homeostasis. The aim of this manuscript is to provide a comprehensive review of the underlying molecular mechanisms of pathogenesis of IRDs by delving into many of the genes associated with IRD development, their protein products, and the pathways interrupted by genetic mutation.
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Preclinical Models of Retinitis Pigmentosa. Methods Mol Biol 2022; 2560:181-215. [PMID: 36481897 DOI: 10.1007/978-1-0716-2651-1_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Retinitis pigmentosa (RP) is the name for a group of phenotypically-related heritable retinal degenerative disorders. Many genes have been implicated as causing variants of RP, and while the clinical phenotypes are remarkably similar, they may differ in age of onset, progression, and severity. Common inheritance patterns for specific genes connected with the development of the disorder include autosomal dominant, autosomal recessive, and X-linked. Modeling the disease in animals and other preclinical systems offers a cost-conscious, ethical, and time-efficient method for studying the disease subtypes. The history of RP models is briefly examined, and both naturally occurring and transgenic preclinical models of RP in many different organisms are discussed. Syndromic forms of RP and models thereof are reviewed as well.
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Perea-Romero I, Solarat C, Blanco-Kelly F, Sanchez-Navarro I, Bea-Mascato B, Martin-Salazar E, Lorda-Sanchez I, Swafiri ST, Avila-Fernandez A, Martin-Merida I, Trujillo-Tiebas MJ, Carreño E, Jimenez-Rolando B, Garcia-Sandoval B, Minguez P, Corton M, Valverde D, Ayuso C. Allelic overload and its clinical modifier effect in Bardet-Biedl syndrome. NPJ Genom Med 2022; 7:41. [PMID: 35835773 PMCID: PMC9283419 DOI: 10.1038/s41525-022-00311-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 06/29/2022] [Indexed: 11/17/2022] Open
Abstract
Bardet–Biedl syndrome (BBS) is an autosomal recessive ciliopathy characterized by extensive inter- and intra-familial variability, in which oligogenic interactions have been also reported. Our main goal is to elucidate the role of mutational load in the clinical variability of BBS. A cohort of 99 patients from 77 different families with biallelic pathogenic variants in a BBS-associated gene was retrospectively recruited. Human Phenotype Ontology terms were used in the annotation of clinical symptoms. The mutational load in 39 BBS-related genes was studied in index cases using different molecular and next-generation sequencing (NGS) approaches. Candidate allele combinations were analysed using the in silico tools ORVAL and DiGePred. After clinical annotation, 76 out of the 99 cases a priori fulfilled established criteria for diagnosis of BBS or BBS-like. BBS1 alleles, found in 42% of families, were the most represented in our cohort. An increased mutational load was excluded in 41% of the index cases (22/54). Oligogenic inheritance was suspected in 52% of the screened families (23/45), being 40 tested by means of NGS data and 5 only by traditional methods. Together, ORVAL and DiGePred platforms predicted an oligogenic effect in 44% of the triallelic families (10/23). Intrafamilial variable severity could be clinically confirmed in six of the families. Our findings show that the presence of more than two alleles in BBS-associated genes correlated in six families with a more severe phenotype and associated with specific findings, highlighting the role of the mutational load in the management of BBS cases.
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Affiliation(s)
- Irene Perea-Romero
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Carlos Solarat
- CINBIO, Universidade de Vigo, Vigo, Spain.,Instituto de Investigación Sanitaria Galicia Sur (IIS Galicia Sur), Álvaro Cunqueiro Hospital, Vigo, Spain
| | - Fiona Blanco-Kelly
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Iker Sanchez-Navarro
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Brais Bea-Mascato
- CINBIO, Universidade de Vigo, Vigo, Spain.,Instituto de Investigación Sanitaria Galicia Sur (IIS Galicia Sur), Álvaro Cunqueiro Hospital, Vigo, Spain
| | - Eduardo Martin-Salazar
- CINBIO, Universidade de Vigo, Vigo, Spain.,Instituto de Investigación Sanitaria Galicia Sur (IIS Galicia Sur), Álvaro Cunqueiro Hospital, Vigo, Spain
| | - Isabel Lorda-Sanchez
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Saoud Tahsin Swafiri
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Almudena Avila-Fernandez
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Inmaculada Martin-Merida
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Maria Jose Trujillo-Tiebas
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Ester Carreño
- Department of Ophthalmology, Fundación Jiménez Díaz University Hospital (FJD), Madrid, Spain
| | - Belen Jimenez-Rolando
- Department of Ophthalmology, Fundación Jiménez Díaz University Hospital (FJD), Madrid, Spain
| | - Blanca Garcia-Sandoval
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Department of Ophthalmology, Fundación Jiménez Díaz University Hospital (FJD), Madrid, Spain
| | - Pablo Minguez
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Marta Corton
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Diana Valverde
- CINBIO, Universidade de Vigo, Vigo, Spain. .,Instituto de Investigación Sanitaria Galicia Sur (IIS Galicia Sur), Álvaro Cunqueiro Hospital, Vigo, Spain.
| | - Carmen Ayuso
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain. .,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.
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Van De Weghe JC, Gomez A, Doherty D. The Joubert-Meckel-Nephronophthisis Spectrum of Ciliopathies. Annu Rev Genomics Hum Genet 2022; 23:301-329. [PMID: 35655331 DOI: 10.1146/annurev-genom-121321-093528] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Joubert syndrome (JS), Meckel syndrome (MKS), and nephronophthisis (NPH) ciliopathy spectrum could be the poster child for advances and challenges in Mendelian human genetics over the past half century. Progress in understanding these conditions illustrates many core concepts of human genetics. The JS phenotype alone is caused by pathogenic variants in more than 40 genes; remarkably, all of the associated proteins function in and around the primary cilium. Primary cilia are near-ubiquitous, microtubule-based organelles that play crucial roles in development and homeostasis. Protruding from the cell, these cellular antennae sense diverse signals and mediate Hedgehog and other critical signaling pathways. Ciliary dysfunction causes many human conditions termed ciliopathies, which range from multiple congenital malformations to adult-onset single-organ failure. Research on the genetics of the JS-MKS-NPH spectrum has spurred extensive functional work exploring the broadly important role of primary cilia in health and disease. This functional work promises to illuminate the mechanisms underlying JS-MKS-NPH in humans, identify therapeutic targets across genetic causes, and generate future precision treatments. Expected final online publication date for the Annual Review of Genomics and Human Genetics, Volume 23 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
| | - Arianna Gomez
- Department of Pediatrics, University of Washington, Seattle, Washington, USA; .,Molecular Medicine and Mechanisms of Disease Program, Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA;
| | - Dan Doherty
- Department of Pediatrics, University of Washington, Seattle, Washington, USA; .,Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA;
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Lange KI, Best S, Tsiropoulou S, Berry I, Johnson CA, Blacque OE. Interpreting ciliopathy-associated missense variants of uncertain significance (VUS) in Caenorhabditis elegans. Hum Mol Genet 2022; 31:1574-1587. [PMID: 34964473 PMCID: PMC9122650 DOI: 10.1093/hmg/ddab344] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/16/2021] [Accepted: 11/17/2021] [Indexed: 12/26/2022] Open
Abstract
Better methods are required to interpret the pathogenicity of disease-associated variants of uncertain significance (VUS), which cannot be actioned clinically. In this study, we explore the use of an animal model (Caenorhabditis elegans) for in vivo interpretation of missense VUS alleles of TMEM67, a cilia gene associated with ciliopathies. CRISPR/Cas9 gene editing was used to generate homozygous knock-in C. elegans worm strains carrying TMEM67 patient variants engineered into the orthologous gene (mks-3). Quantitative phenotypic assays of sensory cilia structure and function (neuronal dye filling, roaming and chemotaxis assays) measured how the variants impacted mks-3 gene function. Effects of the variants on mks-3 function were further investigated by looking at MKS-3::GFP localization and cilia ultrastructure. The quantitative assays in C. elegans accurately distinguished between known benign (Asp359Glu, Thr360Ala) and known pathogenic (Glu361Ter, Gln376Pro) variants. Analysis of eight missense VUS generated evidence that three are benign (Cys173Arg, Thr176Ile and Gly979Arg) and five are pathogenic (Cys170Tyr, His782Arg, Gly786Glu, His790Arg and Ser961Tyr). Results from worms were validated by a genetic complementation assay in a human TMEM67 knock-out hTERT-RPE1 cell line that tests a TMEM67 signalling function. We conclude that efficient genome editing and quantitative functional assays in C. elegans make it a tractable in vivo animal model for rapid, cost-effective interpretation of ciliopathy-associated missense VUS alleles.
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Affiliation(s)
- Karen I Lange
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Sunayna Best
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, West Yorkshire, UK
| | - Sofia Tsiropoulou
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Ian Berry
- Bristol Genetics Laboratory, Pathology Sciences, Southmead Hospital, Bristol BS10 5NB, UK
| | - Colin A Johnson
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, West Yorkshire, UK
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
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10
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Agonists of prostaglandin E 2 receptors as potential first in class treatment for nephronophthisis and related ciliopathies. Proc Natl Acad Sci U S A 2022; 119:e2115960119. [PMID: 35482924 PMCID: PMC9170064 DOI: 10.1073/pnas.2115960119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SignificanceJuvenile nephronophthisis (NPH) is a renal ciliopathy due to a dysfunction of primary cilia for which no curative treatment is available. This paper describes the identification of agonists of prostaglandin E2 receptors as a potential therapeutic approach for the most common NPHP1-associated ciliopathies. We demonstrated that prostaglandin E1 rescues defective ciliogenesis and ciliary composition in NPHP1 patient urine-derived renal tubular cells and improves ciliary and kidney phenotypes in our NPH zebrafish and Nphp1-/- mouse models. In addition, Taprenepag alleviates the severe retinopathy observed in Nphp1-/- mice. Finally, transcriptomic analyses pointed out several pathways downstream the prostaglandin receptors as cell cycle progression, extracellular matrix, or actin cytoskeleton organization. Altogether, our findings provide an alternative for treatment of NPH.
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11
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Tmem138 is localized to the connecting cilium essential for rhodopsin localization and outer segment biogenesis. Proc Natl Acad Sci U S A 2022; 119:e2109934119. [PMID: 35394880 PMCID: PMC9169668 DOI: 10.1073/pnas.2109934119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The connecting cilium (CC) of the photoreceptor provides the only route for the trafficking of the outer segment (OS) proteins. Failure of OS protein transport causes degenerative photoreceptor diseases, including retinitis pigmentosa. We demonstrate that Tmem138, a protein linked to ciliopathy, is localized to the photoreceptor CC. Germline deletion of Tmem138 abolished OS morphogenesis, followed by rapid photoreceptor degeneration. Tmem138 interacts with rhodopsin and two additional CC compartment proteins, Ahi1 and Tmem231, likely forming a membrane complex to facilitate trafficking of rhodopsin and other OS-bound proteins across the CC. The study thus implicates a new line of regulation on the delivery of OS proteins through interactions with CC membrane complex(es) and provides insights into photoreceptor ciliopathy diseases. Photoreceptor connecting cilium (CC) is structurally analogous to the transition zone (TZ) of primary cilia and gates the molecular trafficking between the inner and the outer segment (OS). Retinal dystrophies with underlying CC defects are manifested in a broad array of syndromic conditions known as ciliopathies as well as nonsyndromic retinal degenerations. Despite extensive studies, many questions remain in the mechanism of protein trafficking across the photoreceptor CC. Here, we genetically inactivated mouse Tmem138, a gene encoding a putative transmembrane protein localized to the ciliary TZ and linked to ciliopathies. Germline deletion of Tmem138 abolished OS morphogenesis, followed by rapid photoreceptor degeneration. Tmem138 was found localized to the photoreceptor CC and was required for localization of Ahi1 to the distal subdomain of the CC. Among the examined set of OS proteins, rhodopsin was mislocalized throughout the mutant cell body prior to OS morphogenesis. Ablation of Tmem138 in mature rods recapitulated the molecular changes in the germline mutants, causing failure of disc renewal and disintegration of the OS. Furthermore, Tmem138 interacts reciprocally with rhodopsin and a related protein Tmem231, and the ciliary localization of the latter was also altered in the mutant photoreceptors. Taken together, these results suggest a crucial role of Tmem138 in the functional organization of the CC, which is essential for rhodopsin localization and OS biogenesis.
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12
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Gana S, Serpieri V, Valente EM. Genotype-phenotype correlates in Joubert syndrome: A review. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2022; 190:72-88. [PMID: 35238134 PMCID: PMC9314610 DOI: 10.1002/ajmg.c.31963] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/04/2022] [Accepted: 02/15/2022] [Indexed: 01/20/2023]
Abstract
Joubert syndrome (JS) is a genetically heterogeneous primary ciliopathy characterized by a pathognomonic cerebellar and brainstem malformation, the “molar tooth sign,” and variable organ involvement. Over 40 causative genes have been identified to date, explaining up to 94% of cases. To date, gene‐phenotype correlates have been delineated only for a handful of genes, directly translating into improved counseling and clinical care. For instance, JS individuals harboring pathogenic variants in TMEM67 have a significantly higher risk of liver fibrosis, while pathogenic variants in NPHP1, RPGRIP1L, and TMEM237 are frequently associated to JS with renal involvement, requiring a closer monitoring of liver parameters, or renal functioning. On the other hand, individuals with causal variants in the CEP290 or AHI1 need a closer surveillance for retinal dystrophy and, in case of CEP290, also for chronic kidney disease. These examples highlight how an accurate description of the range of clinical symptoms associated with defects in each causative gene, including the rare ones, would better address prognosis and help guiding a personalized management. This review proposes to address this issue by assessing the available literature, to confirm known, as well as to propose rare gene‐phenotype correlates in JS.
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Affiliation(s)
- Simone Gana
- Neurogenetics Research Center, IRCCS Mondino Foundation, Pavia, Italy
| | | | - Enza Maria Valente
- Neurogenetics Research Center, IRCCS Mondino Foundation, Pavia, Italy.,Department of Molecular Medicine, University of Pavia, Pavia, Italy
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13
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Pollara L, Sottile V, Valente EM. Patient-derived cellular models of primary ciliopathies. J Med Genet 2022; 59:517-527. [DOI: 10.1136/jmedgenet-2021-108315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 01/21/2022] [Indexed: 11/09/2022]
Abstract
Primary ciliopathies are rare inherited disorders caused by structural or functional defects in the primary cilium, a subcellular organelle present on the surface of most cells. Primary ciliopathies show considerable clinical and genetic heterogeneity, with disruption of over 100 genes causing the variable involvement of several organs, including the central nervous system, kidneys, retina, skeleton and liver. Pathogenic variants in one and the same gene may associate with a wide range of ciliopathy phenotypes, supporting the hypothesis that the individual genetic background, with potential additional variants in other ciliary genes, may contribute to a mutational load eventually determining the phenotypic manifestations of each patient. Functional studies in animal models have uncovered some of the pathophysiological mechanisms linking ciliary gene mutations to the observed phenotypes; yet, the lack of reliable human cell models has previously limited preclinical research and the development of new therapeutic strategies for primary ciliopathies. Recent technical advances in the generation of patient-derived two-dimensional (2D) and three-dimensional (3D) cellular models give a new spur to this research, allowing the study of pathomechanisms while maintaining the complexity of the genetic background of each patient, and enabling the development of innovative treatments to target specific pathways. This review provides an overview of available models for primary ciliopathies, from existing in vivo models to more recent patient-derived 2D and 3D in vitro models. We highlight the advantages of each model in understanding the functional basis of primary ciliopathies and facilitating novel regenerative medicine, gene therapy and drug testing strategies for these disorders.
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14
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Roa JN, Ma Y, Mikulski Z, Xu Q, Ilouz R, Taylor SS, Skowronska-Krawczyk D. Protein Kinase A in Human Retina: Differential Localization of Cβ, Cα, RIIα, and RIIβ in Photoreceptors Highlights Non-redundancy of Protein Kinase A Subunits. Front Mol Neurosci 2021; 14:782041. [PMID: 34867193 PMCID: PMC8636463 DOI: 10.3389/fnmol.2021.782041] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 10/22/2021] [Indexed: 11/17/2022] Open
Abstract
Protein kinase A (PKA) signaling is essential for numerous processes but the subcellular localization of specific PKA regulatory (R) and catalytic (C) subunits has yet to be explored comprehensively. Additionally, the localization of the Cβ subunit has never been spatially mapped in any tissue even though ∼50% of PKA signaling in neuronal tissues is thought to be mediated by Cβ. Here we used human retina with its highly specialized neurons as a window into PKA signaling in the brain and characterized localization of PKA Cα, Cβ, RIIα, and RIIβ subunits. We found that each subunit presented a distinct localization pattern. Cα and Cβ were localized in all cell layers (photoreceptors, interneurons, retinal ganglion cells), while RIIα and RIIβ were selectively enriched in photoreceptor cells where both showed distinct patterns of co-localization with Cα but not Cβ. Only Cα was observed in photoreceptor outer segments and at the base of the connecting cilium. Cβ in turn, was highly enriched in mitochondria and was especially prominent in the ellipsoid of cone cells. Further investigation of Cβ using RNA BaseScope technology showed that two Cβ splice variants (Cβ4 and Cβ4ab) likely code for the mitochondrial Cβ proteins. Overall, our data indicates that PKA Cα, Cβ, RIIα, and RIIβ subunits are differentially localized and are likely functionally non-redundant in the human retina. Furthermore, Cβ is potentially important for mitochondrial-associated neurodegenerative diseases previously linked to PKA dysfunction.
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Affiliation(s)
- Jinae N Roa
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, United States
| | - Yuliang Ma
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, United States
| | - Zbigniew Mikulski
- Microscopy and Histology Core Facility, La Jolla Institute for Immunology, La Jolla, CA, United States
| | - Qianlan Xu
- Department of Physiology and Biophysics and Department of Ophthalmology, Center for Translational Vision Research, University of California, Irvine, Irvine, CA, United States
| | - Ronit Ilouz
- The Azrieli Faculty of Medicine, Bar Ilan University, Safed, Israel
| | - Susan S Taylor
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, United States.,Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, United States
| | - Dorota Skowronska-Krawczyk
- Department of Physiology and Biophysics and Department of Ophthalmology, Center for Translational Vision Research, University of California, Irvine, Irvine, CA, United States
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15
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Li D, Hu M, Chen H, Wu X, Wei X, Lin H, Gao X, Wang H, Li M, Ong ACM, Yue Z, Sun L. An Nphp1 knockout mouse model targeting exon 2-20 demonstrates characteristic phenotypes of human Nephronophthisis. Hum Mol Genet 2021; 31:232-243. [PMID: 34415307 DOI: 10.1093/hmg/ddab239] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 06/30/2021] [Accepted: 08/12/2021] [Indexed: 11/13/2022] Open
Abstract
Nephronophthisis (NPH) is the most prevalent monogenetic disorder leading to end-stage renal failure (ESRD) in childhood. Mutations in Nphp1, encoding a cilia-localized protein, account for the majority of NPH cases. Despite its identification many years ago, Nphp1 deletions targeting exon 4 or exon 20 have not reproduced the histological features of human NPH in murine models. In this study, we deleted exon 2-20 of Nphp1 by CRISPR/Cas9 gene editing to create a near-total knockout (KO) mouse model (Nphp1del2-20/del2-20). Nphp1del2-20/del2-20 mice faithfully reproduced the renal and extrarenal phenotypes associated with human NPH, including renal cyst development, tubular basement membrane thickening, retinal degeneration and abnormal spermatogenesis. Importantly, Nphp1 re-expression using an adenoviral-associated-virus-9 (AAV9) vector could partially rescue both renal and retinal phenotypes in Nphp1del2-20/del2-20 mice. Our results reported the first relevant Nphp1 mouse model with renal phenotypes for human disease. It will be a valuable model for future studies of Nphp1 function and to develop novel treatments for this common childhood disease.
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Affiliation(s)
- Dantong Li
- Department of Pediatrics, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Miaoyue Hu
- Department of Pediatrics, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Huamu Chen
- Department of Pediatrics, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Xiaohong Wu
- Department of Pediatrics, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Xiaoya Wei
- Department of Pediatrics, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Hongrong Lin
- Department of Pediatrics, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Xuefei Gao
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Haiyan Wang
- Department of Pediatrics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Min Li
- Department of Pediatrics, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Albert C M Ong
- Kidney Genetics Group, Academic Nephrology Unit, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, UK
| | - Zhihui Yue
- Department of Pediatrics, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Liangzhong Sun
- Department of Pediatrics, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
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16
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Broadening INPP5E phenotypic spectrum: detection of rare variants in syndromic and non-syndromic IRD. NPJ Genom Med 2021; 6:53. [PMID: 34188062 PMCID: PMC8242099 DOI: 10.1038/s41525-021-00214-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 05/21/2021] [Indexed: 02/06/2023] Open
Abstract
Pathogenic variants in INPP5E cause Joubert syndrome (JBTS), a ciliopathy with retinal involvement. However, despite sporadic cases in large cohort sequencing studies, a clear association with non-syndromic inherited retinal degenerations (IRDs) has not been made. We validate this association by reporting 16 non-syndromic IRD patients from ten families with bi-allelic mutations in INPP5E. Additional two patients showed early onset IRD with limited JBTS features. Detailed phenotypic description for all probands is presented. We report 14 rare INPP5E variants, 12 of which have not been reported in previous studies. We present tertiary protein modeling and analyze all INPP5E variants for deleteriousness and phenotypic correlation. We observe that the combined impact of INPP5E variants in JBTS and non-syndromic IRD patients does not reveal a clear genotype-phenotype correlation, suggesting the involvement of genetic modifiers. Our study cements the wide phenotypic spectrum of INPP5E disease, adding proof that sequence defects in this gene can lead to early-onset non-syndromic IRD.
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17
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Birtel J, Spital G, Book M, Habbig S, Bäumner S, Riehmer V, Beck BB, Rosenkranz D, Bolz HJ, Dahmer-Heath M, Herrmann P, König J, Charbel Issa P. NPHP1 gene-associated nephronophthisis is associated with an occult retinopathy. Kidney Int 2021; 100:1092-1100. [PMID: 34153329 DOI: 10.1016/j.kint.2021.06.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 05/04/2021] [Accepted: 06/07/2021] [Indexed: 10/21/2022]
Abstract
Biallelic deletions in the NPHP1 gene are the most frequent molecular defect of nephronophthisis, a kidney ciliopathy and leading cause of hereditary end-stage kidney disease. Nephrocystin 1, the gene product of NPHP1, is also expressed in photoreceptors where it plays an important role in intra-flagellar transport between the inner and outer segments. However, the human retinal phenotype has never been investigated in detail. Here, we characterized retinal features of 16 patients with homozygous deletions of the entire NPHP1 gene. Retinal assessment included multimodal imaging (optical coherence tomography, fundus autofluorescence) and visual function testing (visual acuity, full-field electroretinography, color vision, visual field). Fifteen patients had a mild retinal phenotype that predominantly affected cones, but with relative sparing of the fovea. Despite a predominant cone dysfunction, night vision problems were an early symptom in some cases. The consistent retinal phenotype on optical coherence tomography images included reduced reflectivity and often a granular appearance of the ellipsoid zone, fading or loss of the interdigitation zone, and mild outer retinal thinning. However, there were usually no obvious structural changes visible upon clinical examination and fundus autofluorescence imaging (occult retinopathy). More advanced retinal degeneration might occur with ageing. An identified additional CEP290 variant in one patient with a more severe retinal degeneration may indicate a potential role for genetic modifiers, although this requires further investigation. Thus, diagnostic awareness about this distinct retinal phenotype has implications for the differential diagnosis of nephronophthisis and for individual prognosis of visual function.
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Affiliation(s)
- Johannes Birtel
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK; Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Georg Spital
- Eye Center at St. Franziskus-Hospital Münster, Münster, Germany
| | - Marius Book
- Eye Center at St. Franziskus-Hospital Münster, Münster, Germany
| | - Sandra Habbig
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Sören Bäumner
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Vera Riehmer
- Institute of Human Genetics, University of Cologne, University Hospital of Cologne, Cologne, Germany
| | - Bodo B Beck
- Institute of Human Genetics, University of Cologne, University Hospital of Cologne, Cologne, Germany; Institute of Human Genetics, Center for Molecular Medicine Cologne, Center for Rare Diseases Cologne, University of Cologne, University Hospital of Cologne, Cologne, Germany
| | | | - Hanno J Bolz
- Institute of Human Genetics, University of Cologne, University Hospital of Cologne, Cologne, Germany; Senckenberg Centre for Human Genetics, Frankfurt, Germany
| | - Mareike Dahmer-Heath
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
| | | | - Jens König
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
| | - Peter Charbel Issa
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK; Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
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18
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Chang CF, Brown KM, Yang Y, Brugmann SA. Centriolar Protein C2cd3 Is Required for Craniofacial Development. Front Cell Dev Biol 2021; 9:647391. [PMID: 34211969 PMCID: PMC8239364 DOI: 10.3389/fcell.2021.647391] [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: 12/29/2020] [Accepted: 05/17/2021] [Indexed: 11/13/2022] Open
Abstract
The primary cilium is a ubiquitous, microtubule-based cellular organelle. Primary cilia dysfunction results in a group of disorders termed ciliopathies. C2 domain containing 3 centriole elongation regulator (C2cd3), encodes a centriolar protein essential for ciliogenesis. Mutations in human C2CD3 are associated with the human ciliopathy Oral-Facial-Digital syndrome type 14 (OFD14). In order to better understand the etiology of ciliopathies including OFD14, we generated numerous murine models targeting C2cd3. Initial analysis revealed several tissue-specific isoforms of C2cd3, and while the loss of C2cd3 has previously been reported to result in exencephaly, tight mesencephalic flexure, pericardial edema, abnormal heart looping and a twisted body axis, further analysis revealed that genetic background may also contribute to phenotypic variation. Additional analyses of a conditional allelic series targeting C-terminal PKC-C2 domains or the N-terminal C2CD3N-C2 domain of C2cd3 revealed a variable degree of phenotypic severity, suggesting that while the N-terminal C2CD3N-C2 domain was critical for early embryonic development as a whole, there was also a craniofacial specific role for the C2CD3N-C2 domains. Together, through generation of novel models and evaluation of C2cd3 expression, these data provide valuable insight into mechanisms of pathology for craniofacial ciliopathies that can be further explored in the future.
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Affiliation(s)
- Ching-Fang Chang
- Division of Developmental Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Kari M Brown
- Division of Developmental Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Yanfen Yang
- Division of Developmental Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Samantha A Brugmann
- Division of Developmental Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States.,Division of Plastic Surgery, Department of Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Shriners Children's Hospital, Cincinnati, OH, United States
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19
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Datta P, Cribbs JT, Seo S. Differential requirement of NPHP1 for compartmentalized protein localization during photoreceptor outer segment development and maintenance. PLoS One 2021; 16:e0246358. [PMID: 33961633 PMCID: PMC8104407 DOI: 10.1371/journal.pone.0246358] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 04/20/2021] [Indexed: 12/16/2022] Open
Abstract
Nephrocystin (NPHP1) is a ciliary transition zone protein and its ablation causes nephronophthisis (NPHP) with partially penetrant retinal dystrophy. However, the precise requirements of NPHP1 in photoreceptors are not well understood. Here, we characterize retinal degeneration in a mouse model of NPHP1 and show that NPHP1 is required to prevent infiltration of inner segment plasma membrane proteins into the outer segment during the photoreceptor maturation. We demonstrate that Nphp1 gene-trap mutant mice, which were previously described as null, are likely hypomorphs due to the production of a small quantity of functional mRNAs derived from nonsense-associated altered splicing and skipping of two exons including the one harboring the gene-trap. In homozygous mutant animals, inner segment plasma membrane proteins such as syntaxin-3 (STX3), synaptosomal-associated protein 25 (SNAP25), and interphotoreceptor matrix proteoglycan 2 (IMPG2) accumulate in the outer segment when outer segments are actively elongating. This phenotype, however, is spontaneously ameliorated after the outer segment elongation is completed. Consistent with this, some photoreceptor cell loss (~30%) occurs during the photoreceptor maturation period but it stops afterward. We further show that Nphp1 genetically interacts with Cep290, another NPHP gene, and that a reduction of Cep290 gene dose results in retinal degeneration that continues until adulthood in Nphp1 mutant mice. These findings demonstrate that NPHP1 is required for the confinement of inner segment plasma membrane proteins during the outer segment development, but its requirement diminishes as photoreceptors mature. Our study also suggests that additional mutations in other NPHP genes may influence the penetrance of retinopathy in human NPHP1 patients.
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Affiliation(s)
- Poppy Datta
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Institute for Vision Research, The University of Iowa, Iowa City, IA, United States of America
| | - J. Thomas Cribbs
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Institute for Vision Research, The University of Iowa, Iowa City, IA, United States of America
| | - Seongjin Seo
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Institute for Vision Research, The University of Iowa, Iowa City, IA, United States of America
- * E-mail:
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20
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Tang Y, Tang Q, Wei H, Hu P, Zou D, Liang R, Ling Y. Hub Genes Associated with the Diagnosis of Diabetic Retinopathy. Int J Gen Med 2021; 14:1739-1750. [PMID: 33986612 PMCID: PMC8110263 DOI: 10.2147/ijgm.s311683] [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: 03/19/2021] [Accepted: 04/14/2021] [Indexed: 11/23/2022] Open
Abstract
Purpose This study aimed to identify genes that may be effective in diagnosing or treating diabetic retinopathy (DR), the most common complication of diabetes mellitus (DM). Methods Differentially expressed genes (DEGs) were identified between DR and DM in GSE146615 dataset. DEGs that were consistently up- or down-regulated under both standard glucose and high glucose conditions were identified as common genes and used to generate a protein-protein interaction network and modules. The module genes were assessed for the area under the receiver operating characteristic curve (AUC), leading to the identification of hub genes. Differentially methylated probes in GSE76169 were also compared with common DEGs to identify specific methylation markers of DR. Enrichment analysis was used to explore the biological characteristics. The Short Time-series Expression Miner algorithm was used to identify genes that were progressively dysregulated in the sequence: healthy controls < DM < DR. Results A total of 1917 common genes were identified for seven modules. The eight genes with AUC > 0.8 under high glucose and standard glucose conditions were considered as hub genes. The module genes were significantly enriched during vascular smooth muscle cell development and regulation of oxygen metabolism, while 92 methylation markers were involved in the similar terms. Among the progressively dysregulated genes, three intersection genes under both standard glucose and high glucose conditions were found to be module genes and were considered as key genes. Conclusion We identified eight potential DR-specific diagnostic and therapeutic genes, whose abnormal expression can cause oxidative stress, thus favoring the course of the disease.
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Affiliation(s)
- Yanhui Tang
- Department of Ophthalmology, The Fifth Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, 530022, People's Republic of China.,Department of Ophthalmology, The First People's Hospital of Nanning, Nanning, Guangxi, 530022, People's Republic of China
| | - Qi Tang
- Department of Ophthalmology, The Fifth Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, 530022, People's Republic of China.,Department of Ophthalmology, The First People's Hospital of Nanning, Nanning, Guangxi, 530022, People's Republic of China
| | - Haicheng Wei
- Department of Ophthalmology, The Fifth Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, 530022, People's Republic of China.,Department of Ophthalmology, The First People's Hospital of Nanning, Nanning, Guangxi, 530022, People's Republic of China
| | - Pinzhang Hu
- Department of Ophthalmology, The Fifth Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, 530022, People's Republic of China.,Department of Ophthalmology, The First People's Hospital of Nanning, Nanning, Guangxi, 530022, People's Republic of China
| | - Donghua Zou
- Department of Neurology, The Fifth Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, 530022, People's Republic of China
| | - Rixiong Liang
- Department of Ophthalmology, The Fifth Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, 530022, People's Republic of China.,Department of Ophthalmology, The First People's Hospital of Nanning, Nanning, Guangxi, 530022, People's Republic of China
| | - Yu Ling
- Department of Ophthalmology, The Fifth Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, 530022, People's Republic of China.,Department of Ophthalmology, The First People's Hospital of Nanning, Nanning, Guangxi, 530022, People's Republic of China
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21
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Sharif AS, Gerstner CD, Cady MA, Arshavsky VY, Mitchell C, Ying G, Frederick JM, Baehr W. Deletion of the phosphatase INPP5E in the murine retina impairs photoreceptor axoneme formation and prevents disc morphogenesis. J Biol Chem 2021; 296:100529. [PMID: 33711342 PMCID: PMC8047226 DOI: 10.1016/j.jbc.2021.100529] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/26/2021] [Accepted: 03/08/2021] [Indexed: 12/13/2022] Open
Abstract
INPP5E, also known as pharbin, is a ubiquitously expressed phosphatidylinositol polyphosphate 5-phosphatase that is typically located in the primary cilia and modulates the phosphoinositide composition of membranes. Mutations to or loss of INPP5E is associated with ciliary dysfunction. INPP5E missense mutations of the phosphatase catalytic domain cause Joubert syndrome in humans-a syndromic ciliopathy affecting multiple tissues including the brain, liver, kidney, and retina. In contrast to other primary cilia, photoreceptor INPP5E is prominently expressed in the inner segment and connecting cilium and absent in the outer segment, which is a modified primary cilium dedicated to phototransduction. To investigate how loss of INPP5e causes retina degeneration, we generated mice with a retina-specific KO (Inpp5eF/F;Six3Cre, abbreviated as retInpp5e-/-). These mice exhibit a rapidly progressing rod-cone degeneration resembling Leber congenital amaurosis that is nearly completed by postnatal day 21 (P21) in the central retina. Mutant cone outer segments contain vesicles instead of discs as early as P8. Although P10 mutant outer segments contain structural and phototransduction proteins, axonemal structure and disc membranes fail to form. Connecting cilia of retInpp5e-/- rods display accumulation of intraflagellar transport particles A and B at their distal ends, suggesting disrupted intraflagellar transport. Although INPP5E ablation may not prevent delivery of outer segment-specific proteins by means of the photoreceptor secretory pathway, its absence prevents the assembly of axonemal and disc components. Herein, we suggest a model for INPP5E-Leber congenital amaurosis, proposing how deletion of INPP5E may interrupt axoneme extension and disc membrane elaboration.
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Affiliation(s)
- Ali S Sharif
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, USA
| | - Cecilia D Gerstner
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, USA
| | - Martha A Cady
- Department of Ophthalmology, Duke University, Durham, North Carolina, USA
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University, Durham, North Carolina, USA
| | - Christina Mitchell
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Guoxin Ying
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, USA
| | - Jeanne M Frederick
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, USA
| | - Wolfgang Baehr
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, USA; Department of Neurobiology & Anatomy, University of Utah, Salt Lake City, Utah, USA; Department of Biology, University of Utah, Salt Lake City, Utah, USA.
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22
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Wiegering A, Dildrop R, Vesque C, Khanna H, Schneider-Maunoury S, Gerhardt C. Rpgrip1l controls ciliary gating by ensuring the proper amount of Cep290 at the vertebrate transition zone. Mol Biol Cell 2021; 32:675-689. [PMID: 33625872 PMCID: PMC8108517 DOI: 10.1091/mbc.e20-03-0190] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A range of severe human diseases called ciliopathies is caused by the dysfunction of primary cilia. Primary cilia are cytoplasmic protrusions consisting of the basal body (BB), the axoneme, and the transition zone (TZ). The BB is a modified mother centriole from which the axoneme, the microtubule-based ciliary scaffold, is formed. At the proximal end of the axoneme, the TZ functions as the ciliary gate governing ciliary protein entry and exit. Since ciliopathies often develop due to mutations in genes encoding proteins that localize to the TZ, the understanding of the mechanisms underlying TZ function is of eminent importance. Here, we show that the ciliopathy protein Rpgrip1l governs ciliary gating by ensuring the proper amount of Cep290 at the vertebrate TZ. Further, we identified the flavonoid eupatilin as a potential agent to tackle ciliopathies caused by mutations in RPGRIP1L as it rescues ciliary gating in the absence of Rpgrip1l.
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Affiliation(s)
- Antonia Wiegering
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany.,Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS) - Developmental Biology Unit, 75005 Paris, France
| | - Renate Dildrop
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Christine Vesque
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS) - Developmental Biology Unit, 75005 Paris, France
| | - Hemant Khanna
- Department of Ophthalmology and Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Sylvie Schneider-Maunoury
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS) - Developmental Biology Unit, 75005 Paris, France
| | - Christoph Gerhardt
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany
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23
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Groopman EE, Povysil G, Goldstein DB, Gharavi AG. Rare genetic causes of complex kidney and urological diseases. Nat Rev Nephrol 2020; 16:641-656. [PMID: 32807983 PMCID: PMC7772719 DOI: 10.1038/s41581-020-0325-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2020] [Indexed: 02/08/2023]
Abstract
Although often considered a single-entity, chronic kidney disease (CKD) comprises many pathophysiologically distinct disorders that result in persistently abnormal kidney structure and/or function, and encompass both monogenic and polygenic aetiologies. Rare inherited forms of CKD frequently span diverse phenotypes, reflecting genetic phenomena including pleiotropy, incomplete penetrance and variable expressivity. Use of chromosomal microarray and massively parallel sequencing technologies has revealed that genomic disorders and monogenic aetiologies contribute meaningfully to seemingly complex forms of CKD across different clinically defined subgroups and are characterized by high genetic and phenotypic heterogeneity. Investigations of prevalent genomic disorders in CKD have integrated genetic, bioinformatic and functional studies to pinpoint the genetic drivers underlying their renal and extra-renal manifestations, revealing both monogenic and polygenic mechanisms. Similarly, massively parallel sequencing-based analyses have identified gene- and allele-level variation that contribute to the clinically diverse phenotypes observed for many monogenic forms of nephropathy. Genome-wide sequencing studies suggest that dual genetic diagnoses are found in at least 5% of patients in whom a genetic cause of disease is identified, highlighting the fact that complex phenotypes can also arise from multilocus variation. A multifaceted approach that incorporates genetic and phenotypic data from large, diverse cohorts will help to elucidate the complex relationships between genotype and phenotype for different forms of CKD, supporting personalized medicine for individuals with kidney disease.
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Affiliation(s)
- Emily E Groopman
- Division of Nephrology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Gundula Povysil
- Institute for Genomic Medicine, Columbia University, New York, NY, USA
| | - David B Goldstein
- Institute for Genomic Medicine, Columbia University, New York, NY, USA
| | - Ali G Gharavi
- Division of Nephrology, Columbia University College of Physicians and Surgeons, New York, NY, USA.
- Institute for Genomic Medicine, Columbia University, New York, NY, USA.
- Center for Precision Medicine and Genomics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA.
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24
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Liu Y, Cao S, Yu M, Hu H. TMEM216 Deletion Causes Mislocalization of Cone Opsin and Rhodopsin and Photoreceptor Degeneration in Zebrafish. Invest Ophthalmol Vis Sci 2020; 61:24. [PMID: 32687549 PMCID: PMC7425700 DOI: 10.1167/iovs.61.8.24] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 06/13/2020] [Indexed: 02/06/2023] Open
Abstract
Purpose Mutations in TMEM216, a ciliary transition zone tetraspan transmembrane protein, are linked to Joubert syndrome and Meckel syndrome. Photoreceptor degeneration is a prominent phenotype in Joubert syndrome. How TMEM216 contributes to photoreceptor health is poorly understood. Methods We have generated tmem216 knockout zebrafish by CRISPR genome editing. The impact of TMEM216 deletion on photoreceptors was evaluated by immunofluorescence staining and electron microscopy. Results Homozygous tmem216 knockout zebrafish died before 21 days after fertilization. Their retina exhibited reduced immunoreactivity to rod photoreceptor outer segment marker 4D2 and cone photoreceptor outer segment marker G protein subunit α transducin 2 (GNAT2). Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) revealed an increase in TUNEL-positive nuclei in the knockout retina, indicating photoreceptor degeneration. The tmem216 mutation resulted in shortened photoreceptor ciliary axoneme, as revealed by acetylated α-tubulin immunostaining. Photoreceptors in knockout zebrafish exhibited mislocalization of outer segment proteins such as rhodopsin, GNAT2, and red opsin to the inner segment and cell bodies. Additionally, electron microscopy revealed that the mutant photoreceptors elaborated outer segment with abnormal disc morphology such as shortened discs and vesicles/vacuoles within the outer segment. Conclusion Our results indicate that TMEM216 is essential for normal genesis of outer segment disc structures, transport of outer segment materials, and survival of photoreceptors in zebrafish. These tmem216 knockout zebrafish will be useful in studying how transition zone proteins regulate photoreceptor outer segment formation and maintenance.
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Affiliation(s)
- Yu Liu
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, New York, United States
| | - Shuqin Cao
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, New York, United States
| | - Miao Yu
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, New York, United States
| | - Huaiyu Hu
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, New York, United States
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25
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Shivanna M, Anand M, Chakrabarti S, Khanna H. Ocular Ciliopathies: Genetic and Mechanistic Insights into Developing Therapies. Curr Med Chem 2019; 26:3120-3131. [PMID: 30221600 DOI: 10.2174/0929867325666180917102557] [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: 03/27/2018] [Revised: 06/21/2018] [Accepted: 09/05/2018] [Indexed: 12/12/2022]
Abstract
Developing suitable medicines for genetic diseases requires a detailed understanding of not only the pathways that cause the disease, but also the identification of the genetic components involved in disease manifestation. This article focuses on the complexities associated with ocular ciliopathies - a class of debilitating disorders of the eye caused by ciliary dysfunction. Ciliated cell types have been identified in both the anterior and posterior segments of the eye. Photoreceptors (rods and cones) are the most studied ciliated neurons in the retina, which is located in the posterior eye. The photoreceptors contain a specialized lightsensing outer segment, or cilium. Any defects in the development or maintenance of the outer segment can result in severe retinal ciliopathies, such as retinitis pigmentosa and Leber congenital amaurosis. A role of cilia in the cell types involved in regulating aqueous fluid outflow in the anterior segment of the eye has also been recognized. Defects in these cell types are frequently associated with some forms of glaucoma. Here, we will discuss the significance of understanding the genetic heterogeneity and the pathogenesis of ocular ciliopathies to develop suitable treatment strategies for these blinding disorders.
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Affiliation(s)
- Mahesh Shivanna
- School of Optometry, Massachusetts College of Pharmacy and Health Sciences University, Worcester, MA, United States
| | - Manisha Anand
- UMASS Medical School, Worcester, MA 01605, United States
| | | | - Hemant Khanna
- UMASS Medical School, Worcester, MA 01605, United States
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26
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Nikopoulos K, Cisarova K, Quinodoz M, Koskiniemi-Kuendig H, Miyake N, Farinelli P, Rehman AU, Khan MI, Prunotto A, Akiyama M, Kamatani Y, Terao C, Miya F, Ikeda Y, Ueno S, Fuse N, Murakami A, Wada Y, Terasaki H, Sonoda KH, Ishibashi T, Kubo M, Cremers FPM, Kutalik Z, Matsumoto N, Nishiguchi KM, Nakazawa T, Rivolta C. A frequent variant in the Japanese population determines quasi-Mendelian inheritance of rare retinal ciliopathy. Nat Commun 2019; 10:2884. [PMID: 31253780 PMCID: PMC6599023 DOI: 10.1038/s41467-019-10746-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 05/23/2019] [Indexed: 12/21/2022] Open
Abstract
Hereditary retinal degenerations (HRDs) are Mendelian diseases characterized by progressive blindness and caused by ultra-rare mutations. In a genomic screen of 331 unrelated Japanese patients, we identify a disruptive Alu insertion and a nonsense variant (p.Arg1933*) in the ciliary gene RP1, neither of which are rare alleles in Japan. p.Arg1933* is almost polymorphic (frequency = 0.6%, amongst 12,000 individuals), does not cause disease in homozygosis or heterozygosis, and yet is significantly enriched in HRD patients (frequency = 2.1%, i.e., a 3.5-fold enrichment; p-value = 9.2 × 10-5). Familial co-segregation and association analyses show that p.Arg1933* can act as a Mendelian mutation in trans with the Alu insertion, but might also associate with disease in combination with two alleles in the EYS gene in a non-Mendelian pattern of heredity. Our results suggest that rare conditions such as HRDs can be paradoxically determined by relatively common variants, following a quasi-Mendelian model linking monogenic and complex inheritance.
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Affiliation(s)
- Konstantinos Nikopoulos
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
- Service of Medical Genetics, Lausanne University Hospital (CHUV), 1011, Lausanne, Switzerland
| | - Katarina Cisarova
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Mathieu Quinodoz
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Hanna Koskiniemi-Kuendig
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Pietro Farinelli
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Atta Ur Rehman
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Muhammad Imran Khan
- Department of Human Genetics, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, 6525 GA, Nijmegen, The Netherlands
| | - Andrea Prunotto
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Masato Akiyama
- Laboratory for Statistical Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan
| | - Yoichiro Kamatani
- Laboratory for Statistical Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan
| | - Chikashi Terao
- Laboratory for Statistical Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan
| | - Fuyuki Miya
- Department of Medical Science Mathematics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, 113-8510, Japan
| | - Yasuhiro Ikeda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Shinji Ueno
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Nobuo Fuse
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Sendai, 980-8573, Japan
| | - Akira Murakami
- Department of Ophthalmology, Juntendo University School of Medicine, Tokyo, 113-8421, Japan
| | - Yuko Wada
- Yuko Wada Eye Clinic, Sendai, 980-0011, Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Koh-Hei Sonoda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Tatsuro Ishibashi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Michiaki Kubo
- RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, 6525 GA, Nijmegen, The Netherlands
| | - Zoltán Kutalik
- Institute of Social and Preventive Medicine, Lausanne University Hospital, 1011, Lausanne, Switzerland
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Koji M Nishiguchi
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan
- Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan
| | - Toru Nakazawa
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan
- Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan
| | - Carlo Rivolta
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland.
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK.
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), 4031, Basel, Switzerland.
- University of Basel, 4001, Basel, Switzerland.
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27
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Cend1, a Story with Many Tales: From Regulation of Cell Cycle Progression/Exit of Neural Stem Cells to Brain Structure and Function. Stem Cells Int 2019; 2019:2054783. [PMID: 31191667 PMCID: PMC6525816 DOI: 10.1155/2019/2054783] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/21/2019] [Accepted: 02/07/2019] [Indexed: 12/15/2022] Open
Abstract
Neural stem/precursor cells (NPCs) generate the large variety of neuronal phenotypes comprising the adult brain. The high diversity and complexity of this organ have its origin in embryonic life, during which NPCs undergo symmetric and asymmetric divisions and then exit the cell cycle and differentiate to acquire neuronal identities. During these processes, coordinated regulation of cell cycle progression/exit and differentiation is essential for generation of the appropriate number of neurons and formation of the correct structural and functional neuronal circuits in the adult brain. Cend1 is a neuronal lineage-specific modulator involved in synchronization of cell cycle exit and differentiation of neuronal precursors. It is expressed all along the neuronal lineage, from neural stem/progenitor cells to mature neurons, and is associated with the dynamics of neuron-generating divisions. Functional studies showed that Cend1 has a critical role during neurogenesis in promoting cell cycle exit and neuronal differentiation. Mechanistically, Cend1 acts via the p53-dependent/Cyclin D1/pRb signaling pathway as well as via a p53-independent route involving a tripartite interaction with RanBPM and Dyrk1B. Upon Cend1 function, Notch1 signaling is suppressed and proneural genes such as Mash1 and Neurogenins 1/2 are induced. Due to its neurogenic activity, Cend1 is a promising candidate therapeutic gene for brain repair, while the Cend1 minimal promoter is a valuable tool for neuron-specific gene delivery in the CNS. Mice with Cend1 genetic ablation display increased NPC proliferation, decreased migration, and higher levels of apoptosis during development. As a result, they show in the adult brain deficits in a range of motor and nonmotor behaviors arising from irregularities in cerebellar cortex lamination and impaired Purkinje cell differentiation as well as a paucity in GABAergic interneurons of the cerebral cortex, hippocampus, and amygdala. Taken together, these studies highlight the necessity for Cend1 expression in the formation of a structurally and functionally normal brain.
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28
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Overlap of polymicrogyria, hydrocephalus, and Joubert syndrome in a family with novel truncating mutations in ADGRG1/GPR56 and KIAA0556. Neurogenetics 2019; 20:91-98. [PMID: 30982090 DOI: 10.1007/s10048-019-00577-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 02/15/2019] [Indexed: 12/18/2022]
Abstract
Genetic mutations associated with brain malformations can lead to a spectrum of severity and it is often difficult to determine whether there are additional pathogenic variants contributing to the phenotype. Here, we present a family affected by a severe brain malformation including bilateral polymicrogyria, hydrocephalus, patchy white matter signal changes, and cerebellar and pontine hypoplasia with elongated cerebellar peduncles leading to the molar tooth sign. While the malformation is reminiscent of bilateral frontoparietal polymicrogyria (BFPP), the phenotype is more severe than previously reported and also includes features of Joubert syndrome (JBTS). Via exome sequencing, we identified homozygous truncating mutations in both ADGRG1/GPR56 and KIAA0556, which are known to cause BFPP and mild brain-specific JBTS, respectively. This study shows how two independent mutations can interact leading to complex brain malformations.
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29
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Lessieur EM, Song P, Nivar GC, Piccillo EM, Fogerty J, Rozic R, Perkins BD. Ciliary genes arl13b, ahi1 and cc2d2a differentially modify expression of visual acuity phenotypes but do not enhance retinal degeneration due to mutation of cep290 in zebrafish. PLoS One 2019; 14:e0213960. [PMID: 30970040 PMCID: PMC6457629 DOI: 10.1371/journal.pone.0213960] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 03/28/2019] [Indexed: 01/11/2023] Open
Abstract
Mutations in the gene Centrosomal Protein 290 kDa (CEP290) result in multiple ciliopathies ranging from the neonatal lethal disorder Meckel-Gruber Syndrome to multi-systemic disorders such as Joubert Syndrome and Bardet-Biedl Syndrome to nonsyndromic diseases like Leber Congenital Amaurosis (LCA) and retinitis pigmentosa. Results from model organisms and human genetics studies, have suggest that mutations in genes encoding protein components of the transition zone (TZ) and other cilia-associated proteins can function as genetic modifiers and be a source for CEP290 pleiotropy. We investigated the zebrafish cep290fh297/fh297 mutant, which encodes a nonsense mutation (p.Q1217*). This mutant is viable as adults, exhibits scoliosis, and undergoes a slow, progressive cone degeneration. The cep290fh297/fh297 mutants showed partial mislocalization of the transmembrane protein rhodopsin but not of the prenylated proteins rhodopsin kinase (GRK1) or the rod transducin subunit GNB1. Surprisingly, photoreceptor degeneration did not trigger proliferation of Müller glia, but proliferation of rod progenitors in the outer nuclear layer was significantly increased. To determine if heterozygous mutations in other cilia genes could exacerbate retinal degeneration, we bred cep290fh297/fh297 mutants to arl13b, ahi1, and cc2d2a mutant zebrafish lines. While cep290fh297/fh297 mutants lacking a single allele of these genes did not exhibit accelerated photoreceptor degeneration, loss of one alleles of arl13b or ahi1 reduced visual performance in optokinetic response assays at 5 days post fertilization. Our results indicate that the cep290fh297/fh297 mutant is a useful model to study the role of genetic modifiers on photoreceptor degeneration in zebrafish and to explore how progressive photoreceptor degeneration influences regeneration in adult zebrafish.
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Affiliation(s)
- Emma M. Lessieur
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Ping Song
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Gabrielle C. Nivar
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Ellen M. Piccillo
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Joseph Fogerty
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Richard Rozic
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Brian D. Perkins
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
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30
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Zhu L, Chen L, Yan L, Perkins BD, Li S, Li B, Xu HA, Li XJ. Mutant Ahi1 Affects Retinal Axon Projection in Zebrafish via Toxic Gain of Function. Front Cell Neurosci 2019; 13:81. [PMID: 30949029 PMCID: PMC6438259 DOI: 10.3389/fncel.2019.00081] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 02/18/2019] [Indexed: 12/23/2022] Open
Abstract
Joubert syndrome (JBTS) is an inherited autosomal recessive disorder associated with cerebellum and brainstem malformation and can be caused by mutations in the Abelson helper integration site-1 (AHI1) gene. Although AHI1 mutations in humans cause abnormal cerebellar development and impaired axonal decussation in JBTS, these phenotypes are not robust or are absent in various mouse models with Ahi1 mutations. AHI1 contains an N-terminal coiled-coil domain, multiple WD40 repeats, and a C-terminal Src homology 3 (SH3) domain, suggesting that AHI1 functions as a signaling or scaffolding protein. Since most AHI1 mutations in humans can result in truncated AHI1 proteins lacking WD40 repeats and the SH3 domain, it remains unclear whether mutant AHI1 elicits toxicity via a gain-of-function mechanism by the truncated AHI1. Because Ahi1 in zebrafish and humans share a similar N-terminal region with a coiled-coil domain that is absent in mouse Ahi1, we used zebrafish as a model to investigate whether Ahi1 mutations could affect axonal decussation. Using in situ hybridization, we found that ahi1 is highly expressed in zebrafish ocular tissues, especially in retina, allowing us to examine its effect on retinal ganglion cell (RGC) projection and eye morphology. We injected a morpholino to zebrafish embryos, which can generate mutant Ahi1 lacking the intact WD40 repeats, and found RGC axon misprojection and ocular dysplasia in 4 dpf (days post-fertilization) larvae after the injection. However, ahi1 null zebrafish showed normal RGC axon projection and ocular morphology. We then used CRISPR/Cas9 to generate truncated ahi1 and also found similar defects in the RGC axon projection as seen in those injected with ahi1 morpholino. Thus, the aberrant retinal axon projection in zebrafish is caused by the presence of mutant ahi1 rather than the loss of ahi1, suggesting that mutant Ahi1 may affect axonal decussation via toxic gain of function.
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Affiliation(s)
- Louyin Zhu
- School of Life Sciences and Institute of Life Science, Nanchang University, Nanchang, China.,Jiangxi Provincial Collaborative Innovation Center for Cardiovascular, Digestive and Neuropsychiatric Diseases, Nanchang, China.,Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States
| | - Laiqiang Chen
- School of Life Sciences and Institute of Life Science, Nanchang University, Nanchang, China.,Guangdong-Hongkong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, China
| | - Lingya Yan
- School of Life Sciences and Institute of Life Science, Nanchang University, Nanchang, China
| | - Brian D Perkins
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, United States
| | - Shihua Li
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States
| | - Baoming Li
- School of Life Sciences and Institute of Life Science, Nanchang University, Nanchang, China.,Jiangxi Provincial Collaborative Innovation Center for Cardiovascular, Digestive and Neuropsychiatric Diseases, Nanchang, China
| | - Hong A Xu
- School of Life Sciences and Institute of Life Science, Nanchang University, Nanchang, China.,Jiangxi Provincial Collaborative Innovation Center for Cardiovascular, Digestive and Neuropsychiatric Diseases, Nanchang, China
| | - Xiao-Jiang Li
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States
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Watanabe S, Ino J, Fujimaru T, Taneda S, Akihisa T, Makabe S, Kataoka H, Mori T, Sohara E, Uchida S, Nitta K, Mochizuki T. PKD1 mutation may epistatically ameliorate nephronophthisis progression in patients with NPHP1 deletion. Clin Case Rep 2019; 7:336-339. [PMID: 30847201 PMCID: PMC6389502 DOI: 10.1002/ccr3.1947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 10/28/2018] [Accepted: 11/08/2018] [Indexed: 02/01/2023] Open
Abstract
We report a patient with adult-onset nephronophthisis (NPHP) that was identified a homozygous full gene deletion of NPHP1 and a heterozygous PKD1 mutation. We suggest that the PKD1 mutation may have epistatically ameliorated NPHP disease progression and that the screening of larger cohorts for similar possible epistatic effects is needed.
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Affiliation(s)
- Saki Watanabe
- Department of Medicine, Kidney CenterTokyo Women’s Medical UniversityShinjuku‐kuJapan
- Department of Medicine, Division of NephrologyTodachuo General HospitalTodaJapan
| | - Jun Ino
- Department of Medicine, Division of NephrologyTodachuo General HospitalTodaJapan
| | - Takuya Fujimaru
- Department of Nephrology, Graduate School of Medical and Dental SciencesTokyo Medical and Dental UniversityBunkyo‐kuJapan
| | - Sekiko Taneda
- Department of PathologyTokyo Women’s Medical UniversityShinjuku‐kuJapan
| | - Taro Akihisa
- Department of Medicine, Kidney CenterTokyo Women’s Medical UniversityShinjuku‐kuJapan
| | - Shiho Makabe
- Department of Medicine, Kidney CenterTokyo Women’s Medical UniversityShinjuku‐kuJapan
| | - Hiroshi Kataoka
- Department of Medicine, Kidney CenterTokyo Women’s Medical UniversityShinjuku‐kuJapan
- Clinical Research Division for Polycystic Kidney Disease, Department of Medicine, Kidney CenterTokyo Women’s Medical UniversityShinjuku‐kuJapan
| | - Takayasu Mori
- Department of Nephrology, Graduate School of Medical and Dental SciencesTokyo Medical and Dental UniversityBunkyo‐kuJapan
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental SciencesTokyo Medical and Dental UniversityBunkyo‐kuJapan
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental SciencesTokyo Medical and Dental UniversityBunkyo‐kuJapan
| | - Kosaku Nitta
- Department of Medicine, Kidney CenterTokyo Women’s Medical UniversityShinjuku‐kuJapan
| | - Toshio Mochizuki
- Department of Medicine, Kidney CenterTokyo Women’s Medical UniversityShinjuku‐kuJapan
- Clinical Research Division for Polycystic Kidney Disease, Department of Medicine, Kidney CenterTokyo Women’s Medical UniversityShinjuku‐kuJapan
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Loss of the neurodevelopmental Joubert syndrome causing protein, Ahi1, causes motor and muscle development delays independent of central nervous system involvement. Dev Biol 2019; 448:36-47. [PMID: 30695685 DOI: 10.1016/j.ydbio.2019.01.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 01/25/2019] [Accepted: 01/25/2019] [Indexed: 12/15/2022]
Abstract
Joubert syndrome (JBTS) is a predominantly autosomal recessive neurodevelopmental disorder that presents with characteristic malformations of the cerebellar vermis, superior cerebellar peduncles and midbrain in humans. Accompanying these malformations are a heterogeneous set of clinical symptoms, which frequently include deficits in motor and muscle function, such as hypotonia (low muscle tone) and ataxia (clumsiness). These symptoms are attributed to improper development of the hindbrain, but no direct evidence has been reported linking these in JBTS. Here, we describe muscle developmental defects in a mouse with a targeted deletion of the Abelson helper integration site 1 gene, Ahi1, one of the genes known to cause JBTS in humans. While FVB/NJ Ahi1-/- mice display no gross malformations of the cerebellum, deficits are observed in several measures of motor function, strength, and body development. Specifically, Ahi1-/- mice show delayed physical development, delays in surface reflex righting as neonates, and reductions in grip strength and spontaneous locomotor activity as adults. Additionally, Ahi1-/- mice showed evidence of muscle-specific contributions to this phenotype, such as reductions in 1) myoblast differentiation potential in vitro, 2) muscle desmin expression, and 3) overall muscle mass, myonuclear domain, and muscle fiber cross-sectional area. Together, these data suggest that loss of Ahi1 may cause abnormalities in the differentiation of myoblasts to mature muscle cells. Moreover, Ahi1 loss impacts muscle development directly, outside of any indirect impact of cerebellar malformations, revealing a novel myogenic cause for hypotonia in JBTS.
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Mutations of ADAMTS9 Cause Nephronophthisis-Related Ciliopathy. Am J Hum Genet 2019; 104:45-54. [PMID: 30609407 DOI: 10.1016/j.ajhg.2018.11.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 11/09/2018] [Indexed: 01/09/2023] Open
Abstract
Nephronophthisis-related ciliopathies (NPHP-RCs) are a group of inherited diseases that are associated with defects in primary cilium structure and function. To identify genes mutated in NPHP-RC, we performed homozygosity mapping and whole-exome sequencing for >100 individuals, some of whom were single affected individuals born to consanguineous parents and some of whom were siblings of indexes who were also affected by NPHP-RC. We then performed high-throughput exon sequencing in a worldwide cohort of 800 additional families affected by NPHP-RC. We identified two ADAMTS9 mutations (c.4575_4576del [p.Gln1525Hisfs∗60] and c.194C>G [p.Thr65Arg]) that appear to cause NPHP-RC. Although ADAMTS9 is known to be a secreted extracellular metalloproteinase, we found that ADAMTS9 localized near the basal bodies of primary cilia in the cytoplasm. Heterologously expressed wild-type ADAMTS9, in contrast to mutant proteins detected in individuals with NPHP-RC, localized to the vicinity of the basal body. Loss of ADAMTS9 resulted in shortened cilia and defective sonic hedgehog signaling. Knockout of Adamts9 in IMCD3 cells, followed by spheroid induction, resulted in defective lumen formation, which was rescued by an overexpression of wild-type, but not of mutant, ADAMTS9. Knockdown of adamts9 in zebrafish recapitulated NPHP-RC phenotypes, including renal cysts and hydrocephalus. These findings suggest that the identified mutations in ADAMTS9 cause NPHP-RC and that ADAMTS9 is required for the formation and function of primary cilia.
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Baehr W, Hanke-Gogokhia C, Sharif A, Reed M, Dahl T, Frederick JM, Ying G. Insights into photoreceptor ciliogenesis revealed by animal models. Prog Retin Eye Res 2018; 71:26-56. [PMID: 30590118 DOI: 10.1016/j.preteyeres.2018.12.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 12/10/2018] [Accepted: 12/18/2018] [Indexed: 12/11/2022]
Abstract
Photoreceptors are polarized neurons, with very specific subcellular compartmentalization and unique requirements for protein expression and trafficking. Each photoreceptor contains an outer segment, the site of photon capture that initiates vision, an inner segment that houses the biosynthetic machinery and a synaptic terminal for signal transmission to downstream neurons. Outer segments and inner segments are connected by a connecting cilium (CC), the equivalent of a transition zone (TZ) of primary cilia. The connecting cilium is part of the basal body/axoneme backbone that stabilizes the outer segment. This report will update the reader on late developments in photoreceptor ciliogenesis and transition zone formation, specifically in mouse photoreceptors, focusing on early events in photoreceptor ciliogenesis. The connecting cilium, an elongated and narrow structure through which all outer segment proteins and membrane components must traffic, functions as a gate that controls access to the outer segment. Here we will review genes and their protein products essential for basal body maturation and for CC/TZ genesis, sorted by phenotype. Emphasis is given to naturally occurring mouse mutants and gene knockouts that interfere with CC/TZ formation and ciliogenesis.
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Affiliation(s)
- Wolfgang Baehr
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA.
| | - Christin Hanke-Gogokhia
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Ali Sharif
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Michelle Reed
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Tiffanie Dahl
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Jeanne M Frederick
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Guoxin Ying
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
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Review of Ocular Manifestations of Joubert Syndrome. Genes (Basel) 2018; 9:genes9120605. [PMID: 30518138 PMCID: PMC6315342 DOI: 10.3390/genes9120605] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 11/13/2018] [Accepted: 11/27/2018] [Indexed: 12/13/2022] Open
Abstract
Joubert syndrome is a group of rare disorders that stem from defects in a sensory organelle, the primary cilia. Affected patients often present with disorders involving multiple organ systems, including the brain, eyes, and kidneys. Common symptoms include breathing abnormalities, mental developmental delays, loss of voluntary muscle coordination, and abnormal eye movements, with a diagnostic “molar tooth” sign observed by magnetic resonance imaging (MRI) of the midbrain. We reviewed the ocular phenotypes that can be found in patients with Joubert syndrome. Ocular motor apraxia is the most frequent (80% of patients), followed by strabismus (74%) and nystagmus (72%). A minority of patients also present with ptosis (43%), chorioretinal coloboma (30%), and optic nerve atrophy (22%). Although mutations in 34 genes have been found to be associated with Joubert syndrome, retinal degeneration has been reported in only 38% of patients. Mutations in AHI1 and CEP290, genes critical to primary cilia function, have been linked to retinal degeneration. In conclusion, Joubert syndrome is a rare pleiotropic group of disorders with variable ocular presentations.
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36
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Dharmat R, Eblimit A, Robichaux MA, Zhang Z, Nguyen TMT, Jung SY, He F, Jain A, Li Y, Qin J, Overbeek P, Roepman R, Mardon G, Wensel TG, Chen R. SPATA7 maintains a novel photoreceptor-specific zone in the distal connecting cilium. J Cell Biol 2018; 217:2851-2865. [PMID: 29899041 PMCID: PMC6080925 DOI: 10.1083/jcb.201712117] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/09/2018] [Accepted: 05/23/2018] [Indexed: 12/25/2022] Open
Abstract
Photoreceptor-specific ciliopathies often affect a structure that is considered functionally homologous to the ciliary transition zone (TZ) called the connecting cilium (CC). However, it is unclear how mutations in certain ciliary genes disrupt the photoreceptor CC without impacting the primary cilia systemically. By applying stochastic optical reconstruction microscopy technology in different genetic models, we show that the CC can be partitioned into two regions: the proximal CC (PCC), which is homologous to the TZ of primary cilia, and the distal CC (DCC), a photoreceptor-specific extension of the ciliary TZ. This specialized distal zone of the CC in photoreceptors is maintained by SPATA7, which interacts with other photoreceptor-specific ciliary proteins such as RPGR and RPGRIP1. The absence of Spata7 results in the mislocalization of DCC proteins without affecting the PCC protein complexes. This collapse results in destabilization of the axonemal microtubules, which consequently results in photoreceptor degeneration. These data provide a novel mechanism to explain how genetic disruption of ubiquitously present ciliary proteins exerts tissue-specific ciliopathy phenotypes.
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Affiliation(s)
- Rachayata Dharmat
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX
| | - Aiden Eblimit
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX
| | - Michael A Robichaux
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Zhixian Zhang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Thanh-Minh T Nguyen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Sung Yun Jung
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Feng He
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Antrix Jain
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Yumei Li
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX
| | - Jun Qin
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Paul Overbeek
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Ronald Roepman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Graeme Mardon
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
- Pathology and Immunology, Baylor College of Medicine, Houston, TX
| | - Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Rui Chen
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
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Brooks BP, Zein WM, Thompson AH, Mokhtarzadeh M, Doherty DA, Parisi M, Glass IA, Malicdan MC, Vilboux T, Vemulapalli M, Mullikin JC, Gahl WA, Gunay-Aygun M. Joubert Syndrome: Ophthalmological Findings in Correlation with Genotype and Hepatorenal Disease in 99 Patients Prospectively Evaluated at a Single Center. Ophthalmology 2018; 125:1937-1952. [PMID: 30055837 DOI: 10.1016/j.ophtha.2018.05.026] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 05/25/2018] [Accepted: 05/29/2018] [Indexed: 01/14/2023] Open
Abstract
PURPOSE Joubert syndrome (JS) is caused by mutations in >34 genes that encode proteins involved with primary (nonmotile) cilia and the cilium basal body. This study describes the varying ocular phenotypes in JS patients, with correlation to systemic findings and genotype. DESIGN Patients were systematically and prospectively examined at the National Institutes of Health (NIH) Clinical Center in the setting of a dedicated natural history clinical trial. PARTICIPANTS Ninety-nine patients with JS examined at a single center. METHODS All patients underwent genotyping for JS, followed by complete age-appropriate ophthalmic examinations at the NIH Clinical Center, including visual acuity (VA), fixation behavior, lid position, motility assessment, slit-lamp biomicroscopy, dilated fundus examination with an indirect ophthalmoscope, and retinoscopy. Color and fundus autofluorescence imaging, Optos wide-field photography (Dunfermline, Scotland, UK), and electroretinography (ERG) were performed when possible. MAIN OUTCOME MEASURES The VA (with longitudinal follow-up where possible), ptosis, extraocular muscle function, retinal and optic nerve status, and retinal function as measured by ERG. RESULTS Among patients with JS with quantifiable VA (68/99), values ranged from 0 logarithm of the minimum angle of resolution (logMAR) (Snellen 20/20) to 1.5 logMAR (Snellen 20/632). Strabismus (71/98), nystagmus (66/99), oculomotor apraxia (60/77), ptosis (30/98), coloboma (28/99), retinal degeneration (20/83), and optic nerve atrophy (8/86) were identified. CONCLUSIONS We recommend regular monitoring for ophthalmological manifestations of JS beginning soon after birth or diagnosis. We demonstrate delayed visual development and note that the amblyogenic time frame may last significantly longer in JS than is typical. In general, patients with coloboma were less likely to display retinal degeneration, and those with retinal degeneration did not have coloboma. Severe retinal degeneration that is early and aggressive is seen in disease caused by specific genes, such as CEP290- and AHI1-associated JS. Retinal degeneration in INPP5E-, MKS1-, and NPHP1-associated JS was generally milder. Finally, ptosis surgery can be helpful in a subset of patients with JS; decisions as to timing and benefit/risk ratio need to be made on an individual basis according to expert consultation.
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Affiliation(s)
- Brian P Brooks
- National Eye Institute, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland; National Human Genome Research Institute, Genetics and Molecular Biology Branch, Bethesda, Maryland; Office of the Clinical Director, National Eye Institute, National Institutes of Health, Bethesda, Maryland.
| | - Wadih M Zein
- National Eye Institute, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Amy H Thompson
- National Eye Institute, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland; Columbus Technologies & Services, Inc., Greenbelt, Maryland
| | - Maryam Mokhtarzadeh
- National Eye Institute, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Daniel A Doherty
- Department of Pediatrics, University of Washington, Seattle, Washington; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Melissa Parisi
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Ian A Glass
- Department of Pediatrics, University of Washington, Seattle, Washington; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - May C Malicdan
- National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, Maryland; Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Thierry Vilboux
- National Human Genome Research Institute, Genetics and Molecular Biology Branch, Bethesda, Maryland; Inova Translational Medicine Institute, Falls Church, Virginia
| | - Meghana Vemulapalli
- National Institutes of Health Intramural Sequencing Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - James C Mullikin
- National Institutes of Health Intramural Sequencing Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - William A Gahl
- National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, Maryland; Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland; Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Meral Gunay-Aygun
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland; Johns Hopkins University School of Medicine, Department of Pediatrics and McKusick-Nathans Institute of Genetic Medicine, Baltimore, Maryland
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38
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Luo F, Tao YH. Nephronophthisis: A review of genotype-phenotype correlation. Nephrology (Carlton) 2018; 23:904-911. [PMID: 29717526 PMCID: PMC6175366 DOI: 10.1111/nep.13393] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/13/2018] [Indexed: 12/13/2022]
Abstract
Nephronophthisis is an autosomal recessive cystic kidney disease and one of the most common genetic disorders causing end‐stage renal disease in children. Nephronophthisis is a genetically heterogenous disorder with more than 25 identified genes. In 10%–20% of cases, there are additional features of a ciliopathy syndrome, such as retinal defects, liver fibrosis, skeletal abnormalities, and brain developmental disorders. This review provides an update of the recent advances in the clinical features and related gene mutations of nephronophthisis, and novel approaches for therapy in nephronophthisis patients may be needed. Nephronophthisis (NPHP) is a renal ciliopathy affecting children and young adults. This review gives an update on the recent advances in the clinical features and related gene mutations of NPHP.
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Affiliation(s)
- Fenglan Luo
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Sichuan, Chengdu, China.,Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry Education, West China Second University Hospital, Sichuan University, Sichuan, Chengdu, China
| | - Yu-Hong Tao
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Sichuan, Chengdu, China
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39
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Wiegering A, Dildrop R, Kalfhues L, Spychala A, Kuschel S, Lier JM, Zobel T, Dahmen S, Leu T, Struchtrup A, Legendre F, Vesque C, Schneider-Maunoury S, Saunier S, Rüther U, Gerhardt C. Cell type-specific regulation of ciliary transition zone assembly in vertebrates. EMBO J 2018; 37:embj.201797791. [PMID: 29650680 PMCID: PMC5978567 DOI: 10.15252/embj.201797791] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 03/12/2018] [Accepted: 03/15/2018] [Indexed: 01/07/2023] Open
Abstract
Ciliopathies are life-threatening human diseases caused by defective cilia. They can often be traced back to mutations of genes encoding transition zone (TZ) proteins demonstrating that the understanding of TZ organisation is of paramount importance. The TZ consists of multimeric protein modules that are subject to a stringent assembly hierarchy. Previous reports place Rpgrip1l at the top of the TZ assembly hierarchy in Caenorhabditis elegans By performing quantitative immunofluorescence studies in RPGRIP1L-/- mouse embryos and human embryonic cells, we recognise a different situation in vertebrates in which Rpgrip1l deficiency affects TZ assembly in a cell type-specific manner. In cell types in which the loss of Rpgrip1l alone does not affect all modules, additional truncation or removal of vertebrate-specific Rpgrip1 results in an impairment of all modules. Consequently, Rpgrip1l and Rpgrip1 synergistically ensure the TZ composition in several vertebrate cell types, revealing a higher complexity of TZ assembly in vertebrates than in invertebrates.
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Affiliation(s)
- Antonia Wiegering
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Renate Dildrop
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Lisa Kalfhues
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - André Spychala
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Stefanie Kuschel
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Johanna Maria Lier
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Thomas Zobel
- Center for Advanced Imaging (CAi), Heinrich Heine University, Düsseldorf, Germany
| | - Stefanie Dahmen
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Tristan Leu
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Andreas Struchtrup
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Flora Legendre
- INSERM, U983, Hôpital Necker-Enfants Malades, Paris, France.,Sorbonne Paris Cité, Faculté de Médecine, Université Paris-Descartes, Paris, France
| | - Christine Vesque
- Paris-Seine (IBPS) - Developmental Biology Laboratory, Institut de Biologie, CNRS, UMR7622, INSERM U1156, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, Paris, France
| | - Sylvie Schneider-Maunoury
- Paris-Seine (IBPS) - Developmental Biology Laboratory, Institut de Biologie, CNRS, UMR7622, INSERM U1156, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, Paris, France
| | - Sophie Saunier
- INSERM, U983, Hôpital Necker-Enfants Malades, Paris, France.,Sorbonne Paris Cité, Faculté de Médecine, Université Paris-Descartes, Paris, France
| | - Ulrich Rüther
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Christoph Gerhardt
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
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40
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Wheway G, Nazlamova L, Hancock JT. Signaling through the Primary Cilium. Front Cell Dev Biol 2018; 6:8. [PMID: 29473038 PMCID: PMC5809511 DOI: 10.3389/fcell.2018.00008] [Citation(s) in RCA: 284] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/23/2018] [Indexed: 12/13/2022] Open
Abstract
The presence of single, non-motile “primary” cilia on the surface of epithelial cells has been well described since the 1960s. However, for decades these organelles were believed to be vestigial, with no remaining function, having lost their motility. It wasn't until 2003, with the discovery that proteins responsible for transport along the primary cilium are essential for hedgehog signaling in mice, that the fundamental importance of primary cilia in signal transduction was realized. Little more than a decade later, it is now clear that the vast majority of signaling pathways in vertebrates function through the primary cilium. This has led to the adoption of the term “the cells's antenna” as a description for the primary cilium. Primary cilia are particularly important during development, playing fundamental roles in embryonic patterning and organogenesis, with a suite of inherited developmental disorders known as the “ciliopathies” resulting from mutations in genes encoding cilia proteins. This review summarizes our current understanding of the role of these fascinating organelles in a wide range of signaling pathways.
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Affiliation(s)
- Gabrielle Wheway
- Department of Applied Science, Faculty of Health and Applied Sciences, Centre for Research in Biosciences, University of the West of England, Bristol, United Kingdom
| | - Liliya Nazlamova
- Department of Applied Science, Faculty of Health and Applied Sciences, Centre for Research in Biosciences, University of the West of England, Bristol, United Kingdom
| | - John T Hancock
- Department of Applied Science, Faculty of Health and Applied Sciences, Centre for Research in Biosciences, University of the West of England, Bristol, United Kingdom
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41
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Lai D, Chen M, Su J, Liu X, Rothe K, Hu K, Forrest DL, Eaves CJ, Morin GB, Jiang X. PP2A inhibition sensitizes cancer stem cells to ABL tyrosine kinase inhibitors in BCR-ABL
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human leukemia. Sci Transl Med 2018; 10. [DOI: 10.1126/scitranslmed.aan8735] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
PP2A inhibitors and BCR-ABL inhibitors synergize to kill drug-insensitive leukemia cells.
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Affiliation(s)
- Damian Lai
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
- Department of Medicine, University of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
| | - Min Chen
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
| | - Jiechuang Su
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6H 3N1, Canada
| | - Xiaohu Liu
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
- Department of Medicine, University of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
| | - Katharina Rothe
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6H 3N1, Canada
| | - Kaiji Hu
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
| | - Donna L. Forrest
- Department of Medicine, University of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
- Leukemia/Bone Marrow Transplant Program of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
| | - Connie J. Eaves
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
- Department of Medicine, University of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6H 3N1, Canada
| | - Gregg B. Morin
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6H 3N1, Canada
- Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
| | - Xiaoyan Jiang
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
- Department of Medicine, University of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6H 3N1, Canada
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42
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Phelps IG, Dempsey JC, Grout ME, Isabella CR, Tully HM, Doherty D, Bachmann-Gagescu R. Interpreting the clinical significance of combined variants in multiple recessive disease genes: systematic investigation of Joubert syndrome yields little support for oligogenicity. Genet Med 2018; 20:223-233. [PMID: 28771248 PMCID: PMC5797514 DOI: 10.1038/gim.2017.94] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 05/19/2017] [Indexed: 01/11/2023] Open
Abstract
PurposeNext-generation sequencing (NGS) often identifies multiple rare predicted-deleterious variants (RDVs) in different genes associated with a recessive disorder in a given patient. Such variants have been proposed to contribute to digenicity/oligogenicity or "triallelism" or to act as genetic modifiers.MethodsUsing the recessive ciliopathy Joubert syndrome (JBTS) as a model, we investigated these possibilities systematically, relying on NGS of known JBTS genes in a large JBTS and two control cohorts.Results65% of affected individuals had a recessive genetic cause, while 4.9% were candidates for di-/oligogenicity, harboring heterozygous RDVs in two or more genes, compared with 4.2-8% in controls (P = 0.66-0.21). Based on Exome Aggregation Consortium (ExAC) allele frequencies, the probability of cumulating RDVs in any two JBTS genes is 9.3%. We found no support for triallelism, as no unaffected siblings carried the same biallelic RDVs as their affected relative. Sixty percent of individuals sharing identical causal RDVs displayed phenotypic discordance. Although 38% of affected individuals harbored RDVs in addition to the causal mutations, their presence did not correlate with phenotypic severity.ConclusionOur data offer little support for triallelism or digenicity/oligogenicity as clinically relevant inheritance modes in JBTS. While phenotypic discordance supports the existence of genetic modifiers, identifying clinically relevant modifiers remains challenging.
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Affiliation(s)
- Ian G. Phelps
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | | | - Megan E. Grout
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | | | - Hannah M. Tully
- Department of Neurology, University of Washington, Seattle, Washington
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, Washington
| | - Dan Doherty
- Department of Pediatrics, University of Washington, Seattle, WA, USA
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, Washington
| | - Ruxandra Bachmann-Gagescu
- Institute of Medical Genetics, University of Zurich, Switzerland
- Institute of Molecular Life Sciences, University of Zurich, Switzerland
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43
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Deltas C. Digenic inheritance and genetic modifiers. Clin Genet 2018; 93:429-438. [PMID: 28977688 DOI: 10.1111/cge.13150] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 09/27/2017] [Accepted: 09/28/2017] [Indexed: 12/28/2022]
Abstract
Digenic inheritance (DI) concerns pathologies with the simplest form of multigenic etiology, implicating more than 1 gene (and perhaps the environment). True DI is when biallelic or even triallelic mutations in 2 distinct genes, in cis or in trans, are necessary and sufficient to cause pathology with a defined diagnosis. In true DI, a heterozygous mutation in each of 2 genes alone is not associated with a recognizable phenotype. Well-documented diseases with true DI are so far rare and follow non-Mendelian inheritance. DI is also encountered when by serendipity, pathogenic mutations responsible for 2 distinct disease entities are co-inherited, leading to a mixed phenotype. Also, we can consider many true monogenic Mendelian conditions, which show impressively broad spectrum of phenotypes due to pseudo-DI, as a result of co-inheriting genetic modifiers (GMs). I am herewith reviewing examples of GM and embark on presenting some recent notable examples of true DI, with wider discussion of the literature. Undeniably, the advent of high throughput sequencing is bound to unravel more patients suffering with true DI conditions and elucidate many important GM, thus impacting precision medicine.
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Affiliation(s)
- C Deltas
- College of Medicine, Qatar University, Doha, Qatar.,Department of Biological Sciences, Molecular Medicine Research Center, University of Cyprus, Nicosia, Cyprus
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44
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Rpgrip1 is required for rod outer segment development and ciliary protein trafficking in zebrafish. Sci Rep 2017; 7:16881. [PMID: 29203866 PMCID: PMC5715152 DOI: 10.1038/s41598-017-12838-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 09/14/2017] [Indexed: 12/23/2022] Open
Abstract
Mutations in the RPGR-interacting protein 1 (RPGRIP1) gene cause recessive Leber congenital amaurosis (LCA), juvenile retinitis pigmentosa (RP) and cone-rod dystrophy. RPGRIP1 interacts with other retinal disease-causing proteins and has been proposed to have a role in ciliary protein transport; however, its function remains elusive. Here, we describe a new zebrafish model carrying a nonsense mutation in the rpgrip1 gene. Rpgrip1homozygous mutants do not form rod outer segments and display mislocalization of rhodopsin, suggesting a role for RPGRIP1 in rhodopsin-bearing vesicle trafficking. Furthermore, Rab8, the key regulator of rhodopsin ciliary trafficking, was mislocalized in photoreceptor cells of rpgrip1 mutants. The degeneration of rod cells is early onset, followed by the death of cone cells. These phenotypes are similar to that observed in LCA and juvenile RP patients. Our data indicate RPGRIP1 is necessary for rod outer segment development through regulating ciliary protein trafficking. The rpgrip1 mutant zebrafish may provide a platform for developing therapeutic treatments for RP patients.
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45
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Seo S, Datta P. Photoreceptor outer segment as a sink for membrane proteins: hypothesis and implications in retinal ciliopathies. Hum Mol Genet 2017; 26:R75-R82. [PMID: 28453661 DOI: 10.1093/hmg/ddx163] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 04/24/2017] [Indexed: 12/28/2022] Open
Abstract
The photoreceptor outer segment (OS) is a unique modification of the primary cilium, specialized for light perception. Being homologous organelles, the primary cilium and the OS share common building blocks and molecular machinery to construct and maintain them. The OS, however, has several unique structural features that are not seen in primary cilia. Although these unique features of the OS have been well documented, their implications in protein localization have been under-appreciated. In this review, we compare the structural properties of the primary cilium and the OS, and propose a hypothesis that the OS can act as a sink for membrane proteins. We further discuss the implications of this hypothesis in polarized protein localization in photoreceptors and mechanisms of photoreceptor degeneration in retinal ciliopathies.
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Affiliation(s)
- Seongjin Seo
- Department of Ophthalmology and Visual Sciences, Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Poppy Datta
- Department of Ophthalmology and Visual Sciences, Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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46
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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: 18] [Impact Index Per Article: 2.6] [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.
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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
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47
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Llavona P, Pinelli M, Mutarelli M, Marwah VS, Schimpf-Linzenbold S, Thaler S, Yoeruek E, Vetter J, Kohl S, Wissinger B. Allelic Expression Imbalance in the Human Retinal Transcriptome and Potential Impact on Inherited Retinal Diseases. Genes (Basel) 2017; 8:genes8100283. [PMID: 29053642 PMCID: PMC5664133 DOI: 10.3390/genes8100283] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/11/2017] [Accepted: 10/16/2017] [Indexed: 01/19/2023] Open
Abstract
Inherited retinal diseases (IRDs) are often associated with variable clinical expressivity (VE) and incomplete penetrance (IP). Underlying mechanisms may include environmental, epigenetic, and genetic factors. Cis-acting expression quantitative trait loci (cis-eQTLs) can be implicated in the regulation of genes by favoring or hampering the expression of one allele over the other. Thus, the presence of such loci elicits allelic expression imbalance (AEI) that can be traced by massive parallel sequencing techniques. In this study, we performed an AEI analysis on RNA-sequencing (RNA-seq) data, from 52 healthy retina donors, that identified 194 imbalanced single nucleotide polymorphisms(SNPs) in 67 IRD genes. Focusing on SNPs displaying AEI at a frequency higher than 10%, we found evidence of AEI in several IRD genes regularly associated with IP and VE (BEST1, RP1, PROM1, and PRPH2). Based on these SNPs commonly undergoing AEI, we performed pyrosequencing in an independent sample set of 17 healthy retina donors in order to confirm our findings. Indeed, we were able to validate CDHR1, BEST1, and PROM1 to be subjected to cis-acting regulation. With this work, we aim to shed light on differentially expressed alleles in the human retina transcriptome that, in the context of autosomal dominant IRD cases, could help to explain IP or VE.
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Affiliation(s)
- Pablo Llavona
- Institute for Ophthalmic Research, Centre for Ophthalmology, 72076 Tuebingen, Germany.
| | - Michele Pinelli
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy.
| | | | - Veer Singh Marwah
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy.
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland.
| | | | - Sebastian Thaler
- Center for Ophthalmology, 72076 Tuebingen, Germany. --unituebingen-i09f.de
| | - Efdal Yoeruek
- Center for Ophthalmology, 72076 Tuebingen, Germany.
- Augenklinik Mülheim, 45468 Mülheim an der Ruhr, Germany.
| | - Jan Vetter
- Universitäts-Augenklinik, 55131 Mainz, Germany.
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, 72076 Tuebingen, Germany.
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, 72076 Tuebingen, Germany.
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48
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Men CJ, Bujakowska KM, Comander J, Place E, Bedoukian EC, Zhu X, Leroy BP, Fulton AB, Pierce EA. The importance of genetic testing as demonstrated by two cases of CACNA1F-associated retinal generation misdiagnosed as LCA. Mol Vis 2017; 23:695-706. [PMID: 29062221 PMCID: PMC5640518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 10/08/2017] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To describe in detail cases with an initial diagnosis of Leber congenital amaurosis that were later found to have a hemizygous mutation in the CACNA1F gene. METHODS The patients underwent a detailed ophthalmological evaluation and full-field electroretinography (ERG). Selective targeted capture and whole-exome next-generation sequencing (NGS) were used to find the disease-causing mutations. RESULTS Patient 1 presented at age 3 months with nystagmus, normal visual attention, and a normal fundus exam. ERG responses were severely decreased. Patient 2 presented with nystagmus, severe hyperopia, esotropia, and visual acuity of 20/360 oculus dexter (OD) and 20/270 oculus sinister (OS) at age 5 months. His fundus exam showed slightly increased pigmentation around the foveae. The scotopic ERG responses were severely decreased and photopic responses mildly decreased. Based on the initial presentation, both patients received the clinical diagnosis of Leber congenital amaurosis (LCA). However, genetic testing showed no mutations in known LCA genes. Instead, broader genetic testing using NGS showed point mutations in the CACNA1F gene, which is reported to be associated with type 2 congenital stationary night blindness (CSNB2). CONCLUSIONS These two cases demonstrate the clinical overlap between LCA and CSNB in infants and young children. Genetic testing is an essential tool in these cases and provides a more accurate diagnosis and prognosis for patients with inherited retinal degenerative disorders.
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Affiliation(s)
- Clara J. Men
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA
| | - Kinga M. Bujakowska
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA
| | - Jason Comander
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA
| | - Emily Place
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA
| | - Emma C. Bedoukian
- Ophthalmic Genetics & Visual Electrophysiology, Division of Ophthalmology, The Children’s Hospital of Philadelphia, PA
| | - Xiaosong Zhu
- Ophthalmic Genetics & Visual Electrophysiology, Division of Ophthalmology, The Children’s Hospital of Philadelphia, PA
| | - Bart P. Leroy
- Ophthalmic Genetics & Visual Electrophysiology, Division of Ophthalmology, The Children’s Hospital of Philadelphia, PA,Department of Ophthalmology & Center for Medical Genetics, Ghent University Hospital & Ghent University, Ghent, Belgium
| | - Anne B. Fulton
- Department of Ophthalmology, Boston Children’s Hospital, Boston, MA
| | - Eric A. Pierce
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA
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49
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Bujakowska KM, Liu Q, Pierce EA. Photoreceptor Cilia and Retinal Ciliopathies. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a028274. [PMID: 28289063 DOI: 10.1101/cshperspect.a028274] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Photoreceptors are sensory neurons designed to convert light stimuli into neurological responses. This process, called phototransduction, takes place in the outer segments (OS) of rod and cone photoreceptors. OS are specialized sensory cilia, with analogous structures to those present in other nonmotile cilia. Deficient morphogenesis and/or dysfunction of photoreceptor sensory cilia (PSC) caused by mutations in a variety of photoreceptor-specific and common cilia genes can lead to inherited retinal degenerations (IRDs). IRDs can manifest as isolated retinal diseases or syndromic diseases. In this review, we describe the structure and composition of PSC and different forms of ciliopathies with retinal involvement. We review the genetics of the IRDs, which are monogenic disorders but genetically diverse with regard to causality.
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Affiliation(s)
- Kinga M Bujakowska
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114
| | - Qin Liu
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114
| | - Eric A Pierce
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114
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50
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Lessieur EM, Fogerty J, Gaivin RJ, Song P, Perkins BD. The Ciliopathy Gene ahi1 Is Required for Zebrafish Cone Photoreceptor Outer Segment Morphogenesis and Survival. Invest Ophthalmol Vis Sci 2017; 58:448-460. [PMID: 28118669 PMCID: PMC5270624 DOI: 10.1167/iovs.16-20326] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Purpose Joubert syndrome (JBTS) is an autosomal recessive ciliopathy with considerable phenotypic variability. In addition to central nervous system abnormalities, a subset of JBTS patients exhibit retinal dystrophy and/or kidney disease. Mutations in the AHI1 gene are causative for approximately 10% of all JBTS cases. The purpose of this study was to generate ahi1 mutant alleles in zebrafish and to characterize the retinal phenotypes. Methods Zebrafish ahi1 mutants were generated using transcription activator-like effector nucleases (TALENs). Expression analysis was performed by whole-mount in situ hybridization. Anatomic and molecular characterization of photoreceptors was investigated by histology, electron microscopy, and immunohistochemistry. The optokinetic response (OKR) behavior assay was used to assess visual function. Kidney cilia were evaluated by whole-mount immunostaining. Results The ahi1lri46 mutation in zebrafish resulted in shorter cone outer segments but did not affect visual behavior at 5 days after fertilization (dpf). No defects in rod morphology or rhodopsin localization were observed at 5 dpf. By 5 months of age, cone degeneration and rhodopsin mislocalization in rod photoreceptors was observed. The connecting cilium formed normally and Cc2d2a and Cep290 localized properly. Distal pronephric duct cilia were absent in mutant fish; however, only 9% of ahi1 mutants had kidney cysts by 5 dpf, suggesting that the pronephros remained largely functional. Conclusions The results indicate that Ahi1 is required for photoreceptor disc morphogenesis and outer segment maintenance in zebrafish.
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Affiliation(s)
- Emma M Lessieur
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States 2Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States
| | - Joseph Fogerty
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Robert J Gaivin
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Ping Song
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Brian D Perkins
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States 2Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States
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