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Ali A, Abdullah, Bilal M, Mis EK, Lakhani SA, Ahmad W, Ullah I. Sequence variants in different genes underlying Bardet-Biedl syndrome in four consanguineous families. Mol Biol Rep 2023; 50:9963-9970. [PMID: 37897612 DOI: 10.1007/s11033-023-08816-4] [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: 06/19/2023] [Accepted: 09/11/2023] [Indexed: 10/30/2023]
Abstract
BACKGROUND Bardet-Biedl Syndrome (BBS) is a rare (1:13,500-1-160,000) heterogeneous congenital disorder, characterized by postaxial polydactyly, obesity, hypogonadism, rod-cone dystrophy, cognitive impairment, and renal abnormalities (renal cystic dysplasia, anatomical malformation). To date about twenty-five genes have been identified to cause BBS, which accounts for about 80% of BBS diagnosis. METHODS In the current study, we have performed mutational screening of four Pakistani consanguineous families (A-D) with clinical manifestation of BBS by microsatellite-based genotyping and whole exome sequencing. RESULTS Analysis of the data revealed four variants, including a novel/unique inheritance pattern of compound heterozygous variants, p.(Ser40*) and p.(Thr259Leufs*21), in MKKS gene, novel homozygous variant, p.(Gly251Val)] in BBS7 gene and two previously reported p.(Thr259Leufs*21) in MKKS and p.(Met1Lys) in BBS5 gene. The variants were found segregated with the disorder within the families. CONCLUSION The study not only expanded mutations spectrum in the BBS genes, but this will facilitate diagnosis and genetic counselling of families carrying BBS related phenotypes in Pakistani population.
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Affiliation(s)
- Amjad Ali
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Abdullah
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
- Pediatric Genome Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT, USA
| | - Muhammad Bilal
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Emily Kathryn Mis
- Pediatric Genome Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT, USA
| | - Saquib Ali Lakhani
- Pediatric Genome Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT, USA
| | - Wasim Ahmad
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Imran Ullah
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.
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2
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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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Ning K, Bhuckory MB, Lo CH, Sendayen BE, Kowal TJ, Chen M, Bansal R, Chang KC, Vollrath D, Berbari NF, Mahajan VB, Hu Y, Sun Y. Cilia-associated wound repair mediated by IFT88 in retinal pigment epithelium. Sci Rep 2023; 13:8205. [PMID: 37211572 PMCID: PMC10200793 DOI: 10.1038/s41598-023-35099-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 05/12/2023] [Indexed: 05/23/2023] Open
Abstract
Primary cilia are conserved organelles that integrate extracellular cues into intracellular signals and are critical for diverse processes, including cellular development and repair responses. Deficits in ciliary function cause multisystemic human diseases known as ciliopathies. In the eye, atrophy of the retinal pigment epithelium (RPE) is a common feature of many ciliopathies. However, the roles of RPE cilia in vivo remain poorly understood. In this study, we first found that mouse RPE cells only transiently form primary cilia. We then examined the RPE in the mouse model of Bardet-Biedl Syndrome 4 (BBS4), a ciliopathy associated with retinal degeneration in humans, and found that ciliation in BBS4 mutant RPE cells is disrupted early during development. Next, using a laser-induced injury model in vivo, we found that primary cilia in RPE reassemble in response to laser injury during RPE wound healing and then rapidly disassemble after the repair is completed. Finally, we demonstrated that RPE-specific depletion of primary cilia in a conditional mouse model of cilia loss promoted wound healing and enhanced cell proliferation. In summary, our data suggest that RPE cilia contribute to both retinal development and repair and provide insights into potential therapeutic targets for more common RPE degenerative diseases.
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Affiliation(s)
- Ke Ning
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Mohajeet B Bhuckory
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Chien-Hui Lo
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Brent E Sendayen
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
- Palo Alto Veterans Administration, Palo Alto, CA, USA
| | - Tia J Kowal
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Ming Chen
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Ruchi Bansal
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Kun-Che Chang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Douglas Vollrath
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
- Department of Genetics, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Nicolas F Berbari
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Vinit B Mahajan
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA.
- Palo Alto Veterans Administration, Palo Alto, CA, USA.
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4
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Hassanzadeh S, Sadeghi S, Jafari M, Najafi S, Molavi N, Sherkat R. Ciliary and immune dysfunctions and their genetic background in patients with non-cystic fibrosis bronchiectasis in Central Iran. Ir J Med Sci 2023; 192:277-283. [PMID: 35389161 DOI: 10.1007/s11845-022-02994-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 03/29/2022] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Bronchiectasis is usually caused by recurrent bacterial infections and is characterized by irreversible dilation of the bronchi. In this study, we aimed to give an overview of the genetic backgrounds of patients with non-cystic fibrosis bronchiectasis (NCFB) that have been suspected to an underlying ciliary dysfunction or inborn error of immunity (IEI). METHOD This is a retrospective cross-sectional study. Seventy-one NCFB patients who were referred to the Immunodeficiency Research Center, Isfahan University of Medical Sciences, Isfahan, Iran, from 1996 to 2020 were included. These patients were referred to this center for immunological and genetic evaluation. Genetic analysis with whole-exome sequencing and Sanger sequencing was confirmed in 30 patients. However, the genetic evaluations of 41 patients were either still under evaluation or the patients had refused to be genetically evaluated. RESULT Thirty-eight of our 71 patients (53.52%) were diagnosed with ciliary dysfunction and the detected mutations included mutations in the CCDC65, DNAH11, RSPH1, CCDC40, and GAS8 genes as well as a novel mutation. Thirty-three patients (46.47%) had an IEI and the detected mutations included mutations of the following genes: TNFRSF13B, PTPN2, ZNF341 BTK, TCF3, CD79a, PIK3CD, JAGN1, WAS, RFXANK, STK4, GSDMD, and NEMO. CONCLUSION This study presents an overview of the underlying ciliary and immune dysfunctions and their genetic mutations in NCFB in a highly consanguine population. This would give us a better understanding of the etiologies and the known and novel genetic mutations in NCFB in Iran and, in turn, in the Middle East and North Africa (MENA) region.
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Affiliation(s)
- Shakiba Hassanzadeh
- Acquired Immunodeficiency Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Somayeh Sadeghi
- Acquired Immunodeficiency Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mahbube Jafari
- Acquired Immunodeficiency Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Somayeh Najafi
- Acquired Immunodeficiency Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Newsha Molavi
- Acquired Immunodeficiency Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Roya Sherkat
- Acquired Immunodeficiency Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
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5
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Life-Saver or Undertaker: The Relationship between Primary Cilia and Cell Death in Vertebrate Embryonic Development. J Dev Biol 2022; 10:jdb10040052. [PMID: 36547474 PMCID: PMC9783631 DOI: 10.3390/jdb10040052] [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: 10/29/2022] [Revised: 12/02/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022] Open
Abstract
The development of multicellular organisms requires a tightly coordinated network of cellular processes and intercellular signalling. For more than 20 years, it has been known that primary cilia are deeply involved in the mediation of intercellular signalling and that ciliary dysfunction results in severe developmental defects. Cilia-mediated signalling regulates cellular processes such as proliferation, differentiation, migration, etc. Another cellular process ensuring proper embryonic development is cell death. While the effect of cilia-mediated signalling on many cellular processes has been extensively studied, the relationship between primary cilia and cell death remains largely unknown. This article provides a short review on the current knowledge about this relationship.
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6
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Behavioral Phenotyping of Bbs6 and Bbs8 Knockout Mice Reveals Major Alterations in Communication and Anxiety. Int J Mol Sci 2022; 23:ijms232314506. [PMID: 36498834 PMCID: PMC9741393 DOI: 10.3390/ijms232314506] [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: 10/17/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022] Open
Abstract
The primary cilium is an organelle with a central role in cellular signal perception. Mutations in genes that encode cilia-associated proteins result in a collection of human syndromes collectively termed ciliopathies. Of these, the Bardet-Biedl syndrome (BBS) is considered one of the archetypical ciliopathies, as patients exhibit virtually all respective clinical phenotypes, such as pathological changes of the retina or the kidney. However, the behavioral phenotype associated with ciliary dysfunction has received little attention thus far. Here, we extensively characterized the behavior of two rodent models of BBS, Bbs6/Mkks, and Bbs8/Ttc8 knockout mice concerning social behavior, anxiety, and cognitive abilities. While learning tasks remained unaffected due to the genotype, we observed diminished social behavior and altered communication. Additionally, Bbs knockout mice displayed reduced anxiety. This was not due to altered adrenal gland function or corticosterone serum levels. However, hypothalamic expression of Lsamp, the limbic system associated protein, and Adam10, a protease acting on Lsamp, were reduced. This was accompanied by changes in characteristics of adult hypothalamic neurosphere cultures. In conclusion, we provide evidence that behavioral changes in Bbs knockout mice are mainly found in social and anxiety traits and might be based on an altered architecture of the hypothalamus.
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7
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Sánchez-Bellver L, Férriz-Gordillo A, Carrillo-Pz M, Rabanal L, Garcia-Gonzalo FR, Marfany G. The Deubiquitinating Enzyme USP48 Interacts with the Retinal Degeneration-Associated Proteins UNC119a and ARL3. Int J Mol Sci 2022; 23:ijms232012527. [PMID: 36293380 PMCID: PMC9603860 DOI: 10.3390/ijms232012527] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/15/2022] [Accepted: 10/17/2022] [Indexed: 11/16/2022] Open
Abstract
Proteins related to the ubiquitin-proteasome system play an important role during the differentiation and ciliogenesis of photoreceptor cells. Mutations in several genes involved in ubiquitination and proteostasis have been identified as causative of inherited retinal dystrophies (IRDs) and ciliopathies. USP48 is a deubiquitinating enzyme whose role in the retina is still unexplored although previous studies indicate its relevance for neurosensory organs. In this work, we describe that a pool of endogenous USP48 localises to the basal body in retinal cells and provide data that supports the function of USP48 in the photoreceptor cilium. We also demonstrate that USP48 interacts with the IRD-associated proteins ARL3 and UNC119a, and stabilise their protein levels using different mechanisms. Our results suggest that USP48 may act in the regulation/stabilisation of key ciliary proteins for photoreceptor function, in the modulation of intracellular protein transport, and in ciliary trafficking to the photoreceptor outer segment.
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Affiliation(s)
- Laura Sánchez-Bellver
- Department of Genetics, Microbiology and Statistics, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Andrea Férriz-Gordillo
- Department of Genetics, Microbiology and Statistics, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain
| | - Marc Carrillo-Pz
- Department of Genetics, Microbiology and Statistics, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain
| | - Laura Rabanal
- Department of Genetics, Microbiology and Statistics, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain
| | - Francesc R. Garcia-Gonzalo
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid, 28029 Madrid, Spain
- Instituto de Investigaciones Biomédicas “Alberto Sols”, Consejo Superior de Investigaciones Científicas (CSIC), 28029 Madrid, Spain
- Instituto de Investigación Hospital Universitario La Paz (IdiPAZ), 28029 Madrid, Spain
| | - Gemma Marfany
- Department of Genetics, Microbiology and Statistics, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Institut de Biomedicina-Institut de Recerca Sant Joan de Déu (IBUB-IRSJD), Universitat de Barcelona, 08028 Barcelona, Spain
- DBGen Ocular Genomics, 08028 Barcelona, Spain
- Correspondence:
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Novel Mutations in the MKKS, BBS7, and ALMS1 Genes in Iranian Children with Clinically Suspected Bardet–Biedl Syndrome. Case Rep Ophthalmol Med 2022; 2022:6110775. [PMID: 35912300 PMCID: PMC9334124 DOI: 10.1155/2022/6110775] [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: 03/24/2022] [Accepted: 07/07/2022] [Indexed: 11/18/2022] Open
Abstract
Bardet–Biedl syndrome is a rare autosomal recessive form of syndromic obesity which is characterized by retinal degeneration, obesity, polydactyly, cognitive impairment, and renal and urogenital anomalies. In this study, we used whole-exome sequencing (WES) to investigate the underlying mutations in four Iranian children from consanguineous families with a clinical diagnosis of Bardet–Biedl syndrome (BBS). In three out of four children, we identified one previously reported frameshifting variant in the BBS12 gene (c.265-266delTT, p.L89fs) and two novel nonsense variants in MKKS (c.1196T>G, p.L399X) and BBS7 genes (c.1636C>T, p.Q546X). In the other child, no mutations were detected in known genes for BBS. However, we identified a novel variant in the ALMS1 gene (c.10996delC, p.Q3666fs) indicative of Alström syndrome. All variants were interpreted as pathogenic according to American College of Medical Genetics and Genomics (ACMG) guidelines and confirmed through Sanger sequencing. In conclusion, our results not only expand the spectrum of mutations in BBS and ALMS1 genes but also accentuate the importance of genetic testing for differentiating BBS from Alström syndrome.
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Specialization of the photoreceptor transcriptome by Srrm3-dependent microexons is required for outer segment maintenance and vision. Proc Natl Acad Sci U S A 2022; 119:e2117090119. [PMID: 35858306 PMCID: PMC9303857 DOI: 10.1073/pnas.2117090119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Retinal photoreceptors have a distinct transcriptomic profile compared to other neuronal subtypes, likely reflecting their unique cellular morphology and function in the detection of light stimuli by way of the ciliary outer segment. We discovered a layer of this molecular specialization by revealing that the vertebrate retina expresses the largest number of tissue-enriched microexons of all tissue types. A subset of these microexons is included exclusively in photoreceptor transcripts, particularly in genes involved in cilia biogenesis and vesicle-mediated transport. This microexon program is regulated by Srrm3, a paralog of the neural microexon regulator Srrm4. Despite the fact that both proteins positively regulate retina microexons in vitro, only Srrm3 is highly expressed in mature photoreceptors. Its deletion in zebrafish results in widespread down-regulation of microexon inclusion from early developmental stages, followed by other transcriptomic alterations, severe photoreceptor defects, and blindness. These results shed light on the transcriptomic specialization and functionality of photoreceptors, uncovering unique cell type-specific roles for Srrm3 and microexons with implications for retinal diseases.
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A comprehensive WGS-based pipeline for the identification of new candidate genes in inherited retinal dystrophies. NPJ Genom Med 2022; 7:17. [PMID: 35246562 PMCID: PMC8897414 DOI: 10.1038/s41525-022-00286-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 02/04/2022] [Indexed: 12/11/2022] Open
Abstract
To enhance the use of Whole Genome Sequencing (WGS) in clinical practice, it is still necessary to standardize data analysis pipelines. Herein, we aimed to define a WGS-based algorithm for the accurate interpretation of variants in inherited retinal dystrophies (IRD). This study comprised 429 phenotyped individuals divided into three cohorts. A comparison of 14 pathogenicity predictors, and the re-definition of its cutoffs, were performed using panel-sequencing curated data from 209 genetically diagnosed individuals with IRD (training cohort). The optimal tool combinations, previously validated in 50 additional IRD individuals, were also tested in patients with hereditary cancer (n = 109), and with neurological diseases (n = 47) to evaluate the translational value of this approach (validation cohort). Then, our workflow was applied for the WGS-data analysis of 14 individuals from genetically undiagnosed IRD families (discovery cohort). The statistical analysis showed that the optimal filtering combination included CADDv1.6, MAPP, Grantham, and SIFT tools. Our pipeline allowed the identification of one homozygous variant in the candidate gene CFAP20 (c.337 C > T; p.Arg113Trp), a conserved ciliary gene, which was abundantly expressed in human retina and was located in the photoreceptors layer. Although further studies are needed, we propose CFAP20 as a candidate gene for autosomal recessive retinitis pigmentosa. Moreover, we offer a translational strategy for accurate WGS-data prioritization, which is essential for the advancement of personalized medicine.
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Rocha C, Prinos P. Post-transcriptional and Post-translational Modifications of Primary Cilia: How to Fine Tune Your Neuronal Antenna. Front Cell Neurosci 2022; 16:809917. [PMID: 35295905 PMCID: PMC8918543 DOI: 10.3389/fncel.2022.809917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/19/2022] [Indexed: 12/27/2022] Open
Abstract
Primary cilia direct cellular signaling events during brain development and neuronal differentiation. The primary cilium is a dynamic organelle formed in a multistep process termed ciliogenesis that is tightly coordinated with the cell cycle. Genetic alterations, such as ciliary gene mutations, and epigenetic alterations, such as post-translational modifications and RNA processing of cilia related factors, give rise to human neuronal disorders and brain tumors such as glioblastoma and medulloblastoma. This review discusses the important role of genetics/epigenetics, as well as RNA processing and post-translational modifications in primary cilia function during brain development and cancer formation. We summarize mouse and human studies of ciliogenesis and primary cilia activity in the brain, and detail how cilia maintain neuronal progenitor populations and coordinate neuronal differentiation during development, as well as how cilia control different signaling pathways such as WNT, Sonic Hedgehog (SHH) and PDGF that are critical for neurogenesis. Moreover, we describe how post-translational modifications alter cilia formation and activity during development and carcinogenesis, and the impact of missplicing of ciliary genes leading to ciliopathies and cell cycle alterations. Finally, cilia genetic and epigenetic studies bring to light cellular and molecular mechanisms that underlie neurodevelopmental disorders and brain tumors.
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Affiliation(s)
- Cecilia Rocha
- Early Drug Discovery Unit, Montreal Neurological Institute-Hospital, McGill University, Montreal, QC, Canada
- *Correspondence: Cecilia Rocha,
| | - Panagiotis Prinos
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada
- Panagiotis Prinos,
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12
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Lv X, Xu J, Jiang J, Wu P, Tan R, Wang B. Genetic animal models of scoliosis: A systematical review. Bone 2021; 152:116075. [PMID: 34174503 DOI: 10.1016/j.bone.2021.116075] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/16/2021] [Accepted: 06/17/2021] [Indexed: 02/07/2023]
Abstract
Scoliosis is a complex disease with undetermined pathogenesis and has a strong relationship with genetics. Models of scoliosis in animals have been established for better comprehending its pathogenesis and treatment. In this review, we searched all the genetic animal models with body curvature in databases, and reviewed the related genes and scoliosis types. Meanwhile, we also summarized the pathogenesis of scoliosis reported so far. Summarizing the positive phenotypic animal models contributes to a better understanding on the pathogenesis of scoliosis and facilitates the selection of experimental models when a possible pathogenic factor is concerned.
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Affiliation(s)
- Xin Lv
- Department of Spine Surgery, The Second Xiangya Hospital, Central South University, Changsha 410011, Hunan, China
| | - Jinghong Xu
- Department of Spine Surgery, The Second Xiangya Hospital, Central South University, Changsha 410011, Hunan, China
| | - Jiajiong Jiang
- Department of Spine Surgery, The Second Xiangya Hospital, Central South University, Changsha 410011, Hunan, China
| | - Pengfei Wu
- Department of Spine Surgery, The Second Xiangya Hospital, Central South University, Changsha 410011, Hunan, China
| | - Renchun Tan
- Department of Spine Surgery, The Second Xiangya Hospital, Central South University, Changsha 410011, Hunan, China
| | - Bing Wang
- Department of Spine Surgery, The Second Xiangya Hospital, Central South University, Changsha 410011, Hunan, China.
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Sánchez-Bellver L, Toulis V, Marfany G. On the Wrong Track: Alterations of Ciliary Transport in Inherited Retinal Dystrophies. Front Cell Dev Biol 2021; 9:623734. [PMID: 33748110 PMCID: PMC7973215 DOI: 10.3389/fcell.2021.623734] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/09/2021] [Indexed: 01/14/2023] Open
Abstract
Ciliopathies are a group of heterogeneous inherited disorders associated with dysfunction of the cilium, a ubiquitous microtubule-based organelle involved in a broad range of cellular functions. Most ciliopathies are syndromic, since several organs whose cells produce a cilium, such as the retina, cochlea or kidney, are affected by mutations in ciliary-related genes. In the retina, photoreceptor cells present a highly specialized neurosensory cilium, the outer segment, stacked with membranous disks where photoreception and phototransduction occurs. The daily renewal of the more distal disks is a unique characteristic of photoreceptor outer segments, resulting in an elevated protein demand. All components necessary for outer segment formation, maintenance and function have to be transported from the photoreceptor inner segment, where synthesis occurs, to the cilium. Therefore, efficient transport of selected proteins is critical for photoreceptor ciliogenesis and function, and any alteration in either cargo delivery to the cilium or intraciliary trafficking compromises photoreceptor survival and leads to retinal degeneration. To date, mutations in more than 100 ciliary genes have been associated with retinal dystrophies, accounting for almost 25% of these inherited rare diseases. Interestingly, not all mutations in ciliary genes that cause retinal degeneration are also involved in pleiotropic pathologies in other ciliated organs. Depending on the mutation, the same gene can cause syndromic or non-syndromic retinopathies, thus emphasizing the highly refined specialization of the photoreceptor neurosensory cilia, and raising the possibility of photoreceptor-specific molecular mechanisms underlying common ciliary functions such as ciliary transport. In this review, we will focus on ciliary transport in photoreceptor cells and discuss the molecular complexity underpinning retinal ciliopathies, with a special emphasis on ciliary genes that, when mutated, cause either syndromic or non-syndromic retinal ciliopathies.
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Affiliation(s)
- Laura Sánchez-Bellver
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- Institute of Biomedicine (IBUB-IRSJD), Universitat de Barcelona, Barcelona, Spain
| | - Vasileios Toulis
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- CIBERER, ISCIII, Universitat de Barcelona, Barcelona, Spain
| | - Gemma Marfany
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- Institute of Biomedicine (IBUB-IRSJD), Universitat de Barcelona, Barcelona, Spain
- CIBERER, ISCIII, Universitat de Barcelona, Barcelona, Spain
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14
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Zhou X, Zhou W, Wang C, Wang L, Jin Y, Jia Z, Liu Z, Zheng B. A Comprehensive Analysis and Splicing Characterization of Naturally Occurring Synonymous Variants in the ATP7B Gene. Front Genet 2021; 11:592611. [PMID: 33719328 PMCID: PMC7947925 DOI: 10.3389/fgene.2020.592611] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/16/2020] [Indexed: 12/18/2022] Open
Abstract
Next-generation sequencing is effective for the molecular diagnosis of genetic diseases. However, the identification of the clinical significance of synonymous variants remains a challenge. Our previous study showed that some synonymous variants in ATP7B gene produced splicing disruptions, leading to Wilson disease (WD). To test the hypothesis that synonymous variants of ATP7B cause abnormal splicing by disrupting authentic splice sites or splicing regulatory elements, we used computational tools and minigene assays to characterize 253 naturally occurring ATP7B gene synonymous variants in this study. Human Splicing Finder (HSF) and ESE Finder 3.0 were used to predict the impact of these rare synonymous variants on pre-mRNA splicing. Then, we cloned 14 different wild-type Minigene_ATP7B_ex constructs for in vitro minigene assay, including 16 exons of ATP7B gene. After computational prediction, 85 candidate variants were selected to be introduced into the corresponding Minigene_ATP7B_ex constructs for splicing assays. Using this two-step procedure, we demonstrated that 11 synonymous variants in ExAc database (c.1620C>T, c.3888C>T, c.1554C>T, c.1677C>T, c.1830G>A, c.1875T>A, c.2826C>A, c.4098G>A, c.2994C>T, c.3243G>A, and c.3747G>A) disrupted RNA splicing in vitro, and two (c.1620C>T and c.3243G>A) of these caused a complete exon skipping. The results not only provided a reliable experimental basis for the genetic diagnosis of WD patients but also offered some new insights into the pathogenicity of synonymous variants in genetic diseases.
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Affiliation(s)
- Xiaoying Zhou
- Department of Gastroenterology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Wei Zhou
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Chunli Wang
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Lan Wang
- Department of Gastroenterology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Yu Jin
- Department of Gastroenterology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Zhanjun Jia
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Zhifeng Liu
- Department of Gastroenterology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Bixia Zheng
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
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15
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The Alter Retina: Alternative Splicing of Retinal Genes in Health and Disease. Int J Mol Sci 2021; 22:ijms22041855. [PMID: 33673358 PMCID: PMC7917623 DOI: 10.3390/ijms22041855] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 12/14/2022] Open
Abstract
Alternative splicing of mRNA is an essential mechanism to regulate and increase the diversity of the transcriptome and proteome. Alternative splicing frequently occurs in a tissue- or time-specific manner, contributing to differential gene expression between cell types during development. Neural tissues present extremely complex splicing programs and display the highest number of alternative splicing events. As an extension of the central nervous system, the retina constitutes an excellent system to illustrate the high diversity of neural transcripts. The retina expresses retinal specific splicing factors and produces a large number of alternative transcripts, including exclusive tissue-specific exons, which require an exquisite regulation. In fact, a current challenge in the genetic diagnosis of inherited retinal diseases stems from the lack of information regarding alternative splicing of retinal genes, as a considerable percentage of mutations alter splicing or the relative production of alternative transcripts. Modulation of alternative splicing in the retina is also instrumental in the design of novel therapeutic approaches for retinal dystrophies, since it enables precision medicine for specific mutations.
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16
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Smith CEL, Lake AVR, Johnson CA. Primary Cilia, Ciliogenesis and the Actin Cytoskeleton: A Little Less Resorption, A Little More Actin Please. Front Cell Dev Biol 2020; 8:622822. [PMID: 33392209 PMCID: PMC7773788 DOI: 10.3389/fcell.2020.622822] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 11/24/2020] [Indexed: 12/13/2022] Open
Abstract
Primary cilia are microtubule-based organelles that extend from the apical surface of most mammalian cells, forming when the basal body (derived from the mother centriole) docks at the apical cell membrane. They act as universal cellular "antennae" in vertebrates that receive and integrate mechanical and chemical signals from the extracellular environment, serving diverse roles in chemo-, mechano- and photo-sensation that control developmental signaling, cell polarity and cell proliferation. Mutations in ciliary genes cause a major group of inherited developmental disorders called ciliopathies. There are very few preventative treatments or new therapeutic interventions that modify disease progression or the long-term outlook of patients with these conditions. Recent work has identified at least four distinct but interrelated cellular processes that regulate cilia formation and maintenance, comprising the cell cycle, cellular proteostasis, signaling pathways and structural influences of the actin cytoskeleton. The actin cytoskeleton is composed of microfilaments that are formed from filamentous (F) polymers of globular G-actin subunits. Actin filaments are organized into bundles and networks, and are attached to the cell membrane, by diverse cross-linking proteins. During cell migration, actin filament bundles form either radially at the leading edge or as axial stress fibers. Early studies demonstrated that loss-of-function mutations in ciliopathy genes increased stress fiber formation and impaired ciliogenesis whereas pharmacological inhibition of actin polymerization promoted ciliogenesis. These studies suggest that polymerization of the actin cytoskeleton, F-actin branching and the formation of stress fibers all inhibit primary cilium formation, whereas depolymerization or depletion of actin enhance ciliogenesis. Here, we review the mechanistic basis for these effects on ciliogenesis, which comprise several cellular processes acting in concert at different timescales. Actin polymerization is both a physical barrier to both cilia-targeted vesicle transport and to the membrane remodeling required for ciliogenesis. In contrast, actin may cause cilia loss by localizing disassembly factors at the ciliary base, and F-actin branching may itself activate the YAP/TAZ pathway to promote cilia disassembly. The fundamental role of actin polymerization in the control of ciliogenesis may present potential new targets for disease-modifying therapeutic approaches in treating ciliopathies.
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Affiliation(s)
| | | | - Colin A. Johnson
- Leeds Institute of Medical Research at St. James’s, University of Leeds, Leeds, United Kingdom
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17
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A CRISPR and high-content imaging assay compliant with ACMG/AMP guidelines for clinical variant interpretation in ciliopathies. Hum Genet 2020; 140:593-607. [PMID: 33095315 PMCID: PMC7981318 DOI: 10.1007/s00439-020-02228-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 10/14/2020] [Indexed: 11/04/2022]
Abstract
Ciliopathies are a broad range of inherited developmental and degenerative diseases associated with structural or functional defects in motile or primary non-motile cilia. There are around 200 known ciliopathy disease genes and whilst genetic testing can provide an accurate diagnosis, 24–60% of ciliopathy patients who undergo genetic testing do not receive a genetic diagnosis. This is partly because following current guidelines from the American College of Medical Genetics and the Association for Molecular Pathology, it is difficult to provide a confident clinical diagnosis of disease caused by missense or non-coding variants, which account for more than one-third of cases of disease. Mutations in PRPF31 are the second most common cause of the degenerative retinal ciliopathy autosomal dominant retinitis pigmentosa. Here, we present a high-throughput high-content imaging assay providing quantitative measure of effect of missense variants in PRPF31 which meets the recently published criteria for a baseline standard in vitro test for clinical variant interpretation. This assay utilizes a new PRPF31+/– human retinal cell line generated using CRISPR gene editing to provide a stable cell line with significantly fewer cilia in which novel missense variants are expressed and characterised. We show that high-content imaging of cells expressing missense variants in a ciliopathy gene on a null background can allow characterisation of variants according to the cilia phenotype. We hope that this will be a useful tool for clinical characterisation of PRPF31 variants of uncertain significance, and can be extended to variant classification in other ciliopathies.
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18
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Morbidoni V, Agolini E, Slep KC, Pannone L, Zuccarello D, Cassina M, Grosso E, Gai G, Salviati L, Dallapiccola B, Novelli A, Martinelli S, Trevisson E. Biallelic mutations in the TOGARAM1 gene cause a novel primary ciliopathy. J Med Genet 2020; 58:526-533. [PMID: 32747439 DOI: 10.1136/jmedgenet-2020-106833] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 01/06/2023]
Abstract
BACKGROUND Dysfunction in non-motile cilia is associated with a broad spectrum of developmental disorders characterised by clinical heterogeneity. While over 100 genes have been associated with primary ciliopathies, with wide phenotypic overlap, some patients still lack a molecular diagnosis. OBJECTIVE To investigate and functionally characterise the molecular cause of a malformation disorder observed in two sibling fetuses characterised by microphthalmia, cleft lip and palate, and brain anomalies. METHODS A trio-based whole exome sequencing (WES) strategy was used to identify candidate variants in the TOGARAM1 gene. In silico, in vitro and in vivo (Caenorhabditis elegans) studies were carried out to explore the impact of mutations on protein structure and function, and relevant biological processes. RESULTS TOGARAM1 encodes a member of the Crescerin1 family of proteins regulating microtubule dynamics. Its orthologue in C. elegans, che-12, is expressed in a subset of sensory neurons and localises in the dendritic cilium where it is required for chemosensation. Nematode lines harbouring the corresponding missense variant in TOGARAM1 were generated by CRISPR/Cas9 technology. Although chemotaxis ability on a NaCl gradient was not affected, che-12 point mutants displayed impaired lipophilic dye uptake, with shorter and altered cilia in sensory neurons. Finally, in vitro analysis of microtubule polymerisation in the presence of wild-type or mutant TOG2 domain revealed a faster polymerisation associated with the mutant protein, suggesting aberrant tubulin binding. CONCLUSIONS Our data are in favour of a causative role of TOGARAM1 variants in the pathogenesis of this novel disorder, connecting this gene with primary ciliopathy.
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Affiliation(s)
- Valeria Morbidoni
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy.,Laboratorio di Genetica ed Epidemiologia Clinica, Instituto di Ricerca Pediatrica Citta della Speranza, Padova, Italy
| | - Emanuele Agolini
- Laboratory of Medical Genetics, Ospedale Pediatrico Bambino Gesù, Roma, Italy
| | - Kevin C Slep
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Luca Pannone
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Roma, Italy.,Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, Roma, Italy
| | - Daniela Zuccarello
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy
| | - Matteo Cassina
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy
| | - Enrico Grosso
- Medical Genetics Unit, Azienda Ospedaliera Universitaria Città della Salute e della Scienza di Torino, Torino, Italy
| | - Giorgia Gai
- Medical Genetics Unit, Azienda Ospedaliera Universitaria Città della Salute e della Scienza di Torino, Torino, Italy
| | - Leonardo Salviati
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy.,Laboratorio di Genetica ed Epidemiologia Clinica, Instituto di Ricerca Pediatrica Citta della Speranza, Padova, Italy
| | - Bruno Dallapiccola
- Scientific Directorate, Ospedale Pediatrico Bambino Gesù, Roma, Lazio, Italy
| | - Antonio Novelli
- Laboratory of Medical Genetics, Ospedale Pediatrico Bambino Gesù, Roma, Italy
| | - Simone Martinelli
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Roma, Italy
| | - Eva Trevisson
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy .,Laboratorio di Genetica ed Epidemiologia Clinica, Instituto di Ricerca Pediatrica Citta della Speranza, Padova, Italy
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19
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Gilloteaux J. Primary cilia in the Syrian hamster biliary tract: Bile flow antennae and outlooks about signaling on the hepato-biliary-pancreatic stem cells. TRANSLATIONAL RESEARCH IN ANATOMY 2020. [DOI: 10.1016/j.tria.2020.100063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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20
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Baralle FE, Singh RN, Stamm S. RNA structure and splicing regulation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194448. [PMID: 31730825 DOI: 10.1016/j.bbagrm.2019.194448] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Francisco E Baralle
- Italian Liver Disease Foundation (FIF), Building Q AREA Science Park, Basovizza Campus ss14, Km 163,5, 34149 Trieste, Italy
| | - Ravindra N Singh
- Iowa State University, Department of Biomedical Science, 2034 Veterinary Medicine, Ames, IA 50011, United States.
| | - Stefan Stamm
- University of Kentucky, Department of Molecular and Cellular Biochemistry, College of Medicine, B159 Biomedical Biological Sciences Research Bldg. 741 South Limestone, Lexington, KY 40536, United States
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