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Georgiou M, Robson AG, Fujinami K, de Guimarães TAC, Fujinami-Yokokawa Y, Daich Varela M, Pontikos N, Kalitzeos A, Mahroo OA, Webster AR, Michaelides M. Phenotyping and genotyping inherited retinal diseases: Molecular genetics, clinical and imaging features, and therapeutics of macular dystrophies, cone and cone-rod dystrophies, rod-cone dystrophies, Leber congenital amaurosis, and cone dysfunction syndromes. Prog Retin Eye Res 2024; 100:101244. [PMID: 38278208 DOI: 10.1016/j.preteyeres.2024.101244] [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: 10/26/2023] [Revised: 01/12/2024] [Accepted: 01/15/2024] [Indexed: 01/28/2024]
Abstract
Inherited retinal diseases (IRD) are a leading cause of blindness in the working age population and in children. The scope of this review is to familiarise clinicians and scientists with the current landscape of molecular genetics, clinical phenotype, retinal imaging and therapeutic prospects/completed trials in IRD. Herein we present in a comprehensive and concise manner: (i) macular dystrophies (Stargardt disease (ABCA4), X-linked retinoschisis (RS1), Best disease (BEST1), PRPH2-associated pattern dystrophy, Sorsby fundus dystrophy (TIMP3), and autosomal dominant drusen (EFEMP1)), (ii) cone and cone-rod dystrophies (GUCA1A, PRPH2, ABCA4, KCNV2 and RPGR), (iii) predominant rod or rod-cone dystrophies (retinitis pigmentosa, enhanced S-Cone syndrome (NR2E3), Bietti crystalline corneoretinal dystrophy (CYP4V2)), (iv) Leber congenital amaurosis/early-onset severe retinal dystrophy (GUCY2D, CEP290, CRB1, RDH12, RPE65, TULP1, AIPL1 and NMNAT1), (v) cone dysfunction syndromes (achromatopsia (CNGA3, CNGB3, PDE6C, PDE6H, GNAT2, ATF6), X-linked cone dysfunction with myopia and dichromacy (Bornholm Eye disease; OPN1LW/OPN1MW array), oligocone trichromacy, and blue-cone monochromatism (OPN1LW/OPN1MW array)). Whilst we use the aforementioned classical phenotypic groupings, a key feature of IRD is that it is characterised by tremendous heterogeneity and variable expressivity, with several of the above genes associated with a range of phenotypes.
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Affiliation(s)
- Michalis Georgiou
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
| | - Anthony G Robson
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Kaoru Fujinami
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.
| | - Thales A C de Guimarães
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Yu Fujinami-Yokokawa
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan; Department of Health Policy and Management, Keio University School of Medicine, Tokyo, Japan.
| | - Malena Daich Varela
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Nikolas Pontikos
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Angelos Kalitzeos
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Omar A Mahroo
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Section of Ophthalmology, King s College London, St Thomas Hospital Campus, London, United Kingdom; Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, United Kingdom; Department of Translational Ophthalmology, Wills Eye Hospital, Philadelphia, PA, USA.
| | - Andrew R Webster
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Michel Michaelides
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
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Georgiou M, Robson AG, Uwaydat SH, Ji MH, Shakarchi AF, Pontikos N, Mahroo OA, Cheetham ME, Webster AR, Hardcastle AJ, Michaelides M. RP2-Associated X-linked Retinopathy: Clinical Findings, Molecular Genetics, and Natural History in a Large Cohort of Female Carriers. Am J Ophthalmol 2024; 261:112-120. [PMID: 37977507 PMCID: PMC11139645 DOI: 10.1016/j.ajo.2023.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 10/25/2023] [Accepted: 11/03/2023] [Indexed: 11/19/2023]
Abstract
PURPOSE RP2-associated retinopathy typically causes severe early onset retinitis pigmentosa (RP) in affected males. However, there is a scarcity of reports describing the clinical phenotype of female carriers. We tested the hypothesis that RP2 variants manifest in female carriers with a range of functional and anatomic characteristics. DESIGN Retrospective case series. METHODS Females with disease-causing variants in RP2 were identified from investigation of pedigrees affected by RP2 retinopathy. All case notes and results of molecular genetic testing, retinal imaging (fundus autofluorescence imaging, optical coherence tomography (OCT)), and electrophysiology were reviewed. RESULTS Forty pedigrees were investigated. Twenty-nine pedigrees had obligate carriers or molecularly confirmed female members with recorded relevant history and/or examination. For 8 pedigrees, data were available only from history, with patients reporting affected female relatives with RP in 4 cases and unaffected female relatives in the other 4 cases. Twenty-seven females from 21 pedigrees were examined by a retinal genetics specialist. Twenty-three patients (85%) reported no complaints and had normal vision and 4 patients had RP-associated complaints (15%). Eight patients had normal fundus examination (30%), 10 had a tapetal-like reflex (TLR; 37%), 5 had scattered peripheral pigmentation (19%), and the 4 symptomatic patients had fundus findings compatible with RP (15%). All asymptomatic patients with normal fundus, TLR, or asymptomatic pigmentary changes had a continuous ellipsoid zone on OCT when available. The electroretinograms revealed mild to severe photoreceptor dysfunction in 9 of 11 subjects, often asymmetrical, including 5 with pattern electroretinogram evidence of symmetrical (n = 4) or unilateral (n = 1 subject) macular dysfunction. CONCLUSIONS Most carriers were asymptomatic, exhibiting subclinical characteristics such as TLR and pigmentary changes. However, female carriers of RP2 variants can manifest RP. Family history of affected females with RP does not exclude X-linked disease. The phenotypic spectrum as described herein has prognostic and counselling implications for RP2 carriers and patients.
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Affiliation(s)
- Michalis Georgiou
- From the Moorfields Eye Hospital (M.G., A.G.R., N.P., O.A.M., A.R.W., M.M.), London, United Kingdeom; University College London Institute of Ophthalmology (M.G., A.G.R., N.P., O.A.M., M.E.C., A.R.W., A.J.H., M.M.), University College London, London, United Kingdom; Jones Eye Institute (M.G., S.H.U., M.H.J., A.F.S.), University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Anthony G Robson
- From the Moorfields Eye Hospital (M.G., A.G.R., N.P., O.A.M., A.R.W., M.M.), London, United Kingdeom; University College London Institute of Ophthalmology (M.G., A.G.R., N.P., O.A.M., M.E.C., A.R.W., A.J.H., M.M.), University College London, London, United Kingdom
| | - Sami H Uwaydat
- Jones Eye Institute (M.G., S.H.U., M.H.J., A.F.S.), University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Marco H Ji
- Jones Eye Institute (M.G., S.H.U., M.H.J., A.F.S.), University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Ahmed F Shakarchi
- Jones Eye Institute (M.G., S.H.U., M.H.J., A.F.S.), University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Nikolas Pontikos
- University College London Institute of Ophthalmology (M.G., A.G.R., N.P., O.A.M., M.E.C., A.R.W., A.J.H., M.M.), University College London, London, United Kingdom
| | - Omar A Mahroo
- From the Moorfields Eye Hospital (M.G., A.G.R., N.P., O.A.M., A.R.W., M.M.), London, United Kingdeom; University College London Institute of Ophthalmology (M.G., A.G.R., N.P., O.A.M., M.E.C., A.R.W., A.J.H., M.M.), University College London, London, United Kingdom
| | - Michael E Cheetham
- University College London Institute of Ophthalmology (M.G., A.G.R., N.P., O.A.M., M.E.C., A.R.W., A.J.H., M.M.), University College London, London, United Kingdom
| | - Andrew R Webster
- From the Moorfields Eye Hospital (M.G., A.G.R., N.P., O.A.M., A.R.W., M.M.), London, United Kingdeom; University College London Institute of Ophthalmology (M.G., A.G.R., N.P., O.A.M., M.E.C., A.R.W., A.J.H., M.M.), University College London, London, United Kingdom
| | - Alison J Hardcastle
- From the Moorfields Eye Hospital (M.G., A.G.R., N.P., O.A.M., A.R.W., M.M.), London, United Kingdeom; University College London Institute of Ophthalmology (M.G., A.G.R., N.P., O.A.M., M.E.C., A.R.W., A.J.H., M.M.), University College London, London, United Kingdom
| | - Michel Michaelides
- From the Moorfields Eye Hospital (M.G., A.G.R., N.P., O.A.M., A.R.W., M.M.), London, United Kingdeom; University College London Institute of Ophthalmology (M.G., A.G.R., N.P., O.A.M., M.E.C., A.R.W., A.J.H., M.M.), University College London, London, United Kingdom.
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Masek M, Bachmann-Gagescu R. Control of protein and lipid composition of photoreceptor outer segments-Implications for retinal disease. Curr Top Dev Biol 2023; 155:165-225. [PMID: 38043951 DOI: 10.1016/bs.ctdb.2023.09.001] [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] [Indexed: 12/05/2023]
Abstract
Vision is arguably our most important sense, and its loss brings substantial limitations to daily life for affected individuals. Light is perceived in retinal photoreceptors (PRs), which are highly specialized neurons subdivided into several compartments with distinct functions. The outer segments (OSs) of photoreceptors represent highly specialized primary ciliary compartments hosting the phototransduction cascade, which transforms incoming light into a neuronal signal. Retinal disease can result from various pathomechanisms originating in distinct subcompartments of the PR cell, or in the retinal pigment epithelium which supports the PRs. Dysfunction of primary cilia causes human disorders known as "ciliopathies", in which retinal disease is a common feature. This chapter focuses on PR OSs, discussing the mechanisms controlling their complex structure and composition. A sequence of tightly regulated sorting and trafficking events, both upstream of and within this ciliary compartment, ensures the establishment and maintenance of the adequate proteome and lipidome required for signaling in response to light. We discuss in particular our current understanding of the role of ciliopathy proteins involved in multi-protein complexes at the ciliary transition zone (CC2D2A) or BBSome (BBS1) and how their dysfunction causes retinal disease. While the loss of CC2D2A prevents the fusion of vesicles and delivery of the photopigment rhodopsin to the ciliary base, leading to early OS ultrastructural defects, BBS1 deficiency results in precocious accumulation of cholesterol in mutant OSs and decreased visual function preceding morphological changes. These distinct pathomechanisms underscore the central role of ciliary proteins involved in multiple processes controlling OS protein and lipid composition.
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Affiliation(s)
- Markus Masek
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland; Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Ruxandra Bachmann-Gagescu
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland; Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland; University Research Priority Program AdaBD, University of Zurich, Zurich, Switzerland.
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Georgiou M, Robson AG, Jovanovic K, Guimarães TACD, Ali N, Pontikos N, Uwaydat SH, Mahroo OA, Cheetham ME, Webster AR, Hardcastle AJ, Michaelides M. RP2-Associated X-linked Retinopathy: Clinical Findings, Molecular Genetics, and Natural History. Ophthalmology 2023; 130:413-422. [PMID: 36423731 PMCID: PMC10567581 DOI: 10.1016/j.ophtha.2022.11.015] [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: 09/21/2022] [Revised: 11/10/2022] [Accepted: 11/10/2022] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To review and describe in detail the clinical course, functional and anatomic characteristics of RP2-associated retinal degeneration. DESIGN Retrospective case series. PARTICIPANTS Male participants with disease-causing variants in the RP2 gene. METHODS Review of all case notes and results of molecular genetic testing, retinal imaging (fundus autofluorescence [FAF] imaging, OCT), and electrophysiology assessment. MAIN OUTCOME MEASURES Molecular genetic testing, clinical findings including best-corrected visual acuity (BCVA), qualitative and quantitative retinal imaging analysis, and electrophysiology parameters. RESULTS Fifty-four molecularly confirmed patients were identified from 38 pedigrees. Twenty-eight disease-causing variants were identified, with 20 not previously clinically characterized. Fifty-three patients (98.1%) presented with retinitis pigmentosa. The mean age of onset (range ± standard deviation [SD]) was 9.6 years (1-57 ± 9.2 years). Forty-four patients (91.7%) had childhood-onset disease, with mean age of onset of 7.6 years. The most common first symptom was night blindness (68.8%). Mean BCVA (range ± SD) was 0.91 logarithm of the minimum angle of resolution (logMAR) (0-2.7 ± 0.80) and 0.94 logMAR (0-2.7 ± 0.78) for right and left eyes, respectively. On the basis of the World Health Organization visual impairment criteria, 18 patients (34%) had low vision. The majority (17/22) showed electroretinogram (ERG) evidence of a rod-cone dystrophy. Pattern ERG P50 was undetectable in all but 2 patients. A range of FAF findings was observed, from normal to advanced atrophy. There were no statistically significant differences between right and left eyes for ellipsoid zone width (EZW) and outer nuclear layer (ONL) thickness. The mean annual rate of EZW loss was 219 μm/year, and the mean annual decrease in ONL thickness was 4.93 μm/year. No patient with childhood-onset disease had an identifiable ellipsoid zone (EZ) after the age of 26 years at baseline or follow-up. Four patients had adulthood-onset disease and a less severe phenotype. CONCLUSIONS This study details the clinical phenotype of RP2 retinopathy in a large cohort. The majority presented with early-onset severe retinal degeneration, with early macular involvement and complete loss of the foveal photoreceptor layer by the third decade of life. Full-field ERGs revealed rod-cone dystrophy in the vast majority, but with generalized (peripheral) cone system involvement of widely varying severity in the first 2 decades of life. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.
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Affiliation(s)
- Michalis Georgiou
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Anthony G Robson
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Katarina Jovanovic
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Thales A C de Guimarães
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Naser Ali
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Nikolas Pontikos
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Sami H Uwaydat
- Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Omar A Mahroo
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Michael E Cheetham
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Andrew R Webster
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Alison J Hardcastle
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Michel Michaelides
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
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Cheloni R, Jackson D, Moosajee M. A Natural History Study of RP2-Related Retinopathy. J Clin Med 2022; 11:jcm11236877. [PMID: 36498452 PMCID: PMC9738434 DOI: 10.3390/jcm11236877] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/10/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022] Open
Abstract
X-linked retinitis pigmentosa (RP) is a severe form of RP, often with early macular involvement. This study aimed to characterise the natural history of patients with a diagnosis of X-linked RP due to RP2 mutations. Clinical details, best-corrected visual acuity (BCVA) and multimodal retinal imaging were retrospectively collected from patients with RP2 variants from Moorfields Eye Hospital (London, UK). Measures of the ellipsoid-zone (EZ) width, central retinal thickness (CRT), and thickness of the photoreceptor and retinal pigment epithelium complex (PR+RPE, taken between the external limiting membrane and RPE) were extracted from spectral-domain optical coherence tomography (SD-OCT) scans. A total of 47 affected males (median baseline age: 20 years, IQR: 12.5−36.5) were included, and 41 had two or more visits (median follow-up: 8.0 years, IQR: 3.2−14.5). A total of 24 RP2 variants were identified, 13 of which were novel. BCVA dropped from 0.66 LogMAR at baseline (IQR, 0.35−1.4) to 1.3 LogMAR at the most recent visit (IQR: 0.6−1.4). SD-OCT revealed a prevalent outer retinal atrophy (n = 23/35, 65.7%), and measurable EZ width at baseline in 34.3% of patients (n = 12). Age significantly affected all quantitative measures (p < 0.001) except EZ width (p = 0.58), with exponential decays of 46−49% and 12.6−33.9% per decade for BCVA and SD-OCT measures, respectively. RP2 patients exhibited rapid progression to outer retina atrophy and early macular involvement with substantial vision loss by age 30−40.
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Affiliation(s)
- Riccardo Cheloni
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
| | - Daniel Jackson
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
| | - Mariya Moosajee
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- The Francis Crick Institute, London NW1 1AT, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
- Correspondence:
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A multivesicular body-like organelle mediates stimulus-regulated trafficking of olfactory ciliary transduction proteins. Nat Commun 2022; 13:6889. [PMID: 36371422 PMCID: PMC9653401 DOI: 10.1038/s41467-022-34604-y] [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: 05/16/2022] [Accepted: 10/28/2022] [Indexed: 11/13/2022] Open
Abstract
Stimulus transduction in cilia of olfactory sensory neurons is mediated by odorant receptors, Gαolf, adenylate cyclase-3, cyclic nucleotide-gated and chloride ion channels. Mechanisms regulating trafficking and localization of these proteins in the dendrite are unknown. By lectin/immunofluorescence staining and in vivo correlative light-electron microscopy (CLEM), we identify a retinitis pigmentosa-2 (RP2), ESCRT-0 and synaptophysin-containing multivesicular organelle that is not part of generic recycling/degradative/exosome pathways. The organelle's intraluminal vesicles contain the olfactory transduction proteins except for Golf subunits Gγ13 and Gβ1. Instead, Gβ1 colocalizes with RP2 on the organelle's outer membrane. The organelle accumulates in response to stimulus deprivation, while odor stimuli or adenylate cyclase activation cause outer membrane disintegration, release of intraluminal vesicles, and RP2/Gβ1 translocation to the base of olfactory cilia. Together, these findings reveal the existence of a dendritic organelle that mediates both stimulus-regulated storage of olfactory ciliary transduction proteins and membrane-delimited sorting important for G protein heterotrimerization.
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Hibbard JVK, Vázquez N, Wallingford JB. Cilia proteins getting to work - how do they commute from the cytoplasm to the base of cilia? J Cell Sci 2022; 135:jcs259444. [PMID: 36073764 PMCID: PMC9482345 DOI: 10.1242/jcs.259444] [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] [Indexed: 11/20/2022] Open
Abstract
Cilia are multifunctional organelles that originated with the last eukaryotic common ancestor and play central roles in the life cycles of diverse organisms. The motile flagella that move single cells like sperm or unicellular organisms, the motile cilia on animal multiciliated cells that generate fluid flow in organs, and the immotile primary cilia that decorate nearly all cells in animals share many protein components in common, yet each also requires specialized proteins to perform their specialized functions. Despite a now-advanced understanding of how such proteins are transported within cilia, we still know very little about how they are transported from their sites of synthesis through the cytoplasm to the ciliary base. Here, we review the literature concerning this underappreciated topic in ciliary cell biology. We discuss both general mechanisms, as well as specific examples of motor-driven active transport and passive transport via diffusion-and-capture. We then provide deeper discussion of specific, illustrative examples, such as the diverse array of protein subunits that together comprise the intraflagellar transport (IFT) system and the multi-protein axonemal dynein motors that drive beating of motile cilia. We hope this Review will spur further work, shedding light not only on ciliogenesis and ciliary signaling, but also on intracellular transport in general.
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Affiliation(s)
| | | | - John B. Wallingford
- Department of Molecular Biosciences, University of Texas, Austin, TX 78751, USA
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Dutta P, Ray K. Ciliary membrane, localised lipid modification and cilia function. J Cell Physiol 2022; 237:2613-2631. [PMID: 35661356 DOI: 10.1002/jcp.30787] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 05/06/2022] [Accepted: 05/11/2022] [Indexed: 11/08/2022]
Abstract
Cilium, a tiny microtubule-based cellular appendage critical for cell signalling and physiology, displays a large variety of receptors. The composition and turnover of ciliary lipids and receptors determine cell behaviour. Due to the exclusion of ribosomal machinery and limited membrane area, a cilium needs adaptive logistics to actively reconstitute the lipid and receptor compositions during development and differentiation. How is this dynamicity generated? Here, we examine whether, along with the Intraflagellar-Transport, targeted changes in sector-wise lipid composition could control the receptor localisation and functions in the cilia. We discuss how an interplay between ciliary lipid composition, localised lipid modification, and receptor function could contribute to cilia growth and signalling. We argue that lipid modification at the cell-cilium interface could generate an added thrust for a selective exchange of membrane lipids and the transmembrane and membrane-associated proteins.
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Affiliation(s)
- Priya Dutta
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Krishanu Ray
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
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Moran AL, Carter SP, Kaylor JJ, Jiang Z, Broekman S, Dillon ET, Gómez Sánchez A, Minhas SK, van Wijk E, Radu RA, Travis GH, Carey M, Blacque OE, Kennedy BN. Dawn and dusk peaks of outer segment phagocytosis, and visual cycle function require Rab28. FASEB J 2022; 36:e22309. [PMID: 35471581 PMCID: PMC9322422 DOI: 10.1096/fj.202101897r] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 03/14/2022] [Accepted: 03/29/2022] [Indexed: 12/12/2022]
Abstract
RAB28 is a farnesylated, ciliary G-protein. Patient variants in RAB28 are causative of autosomal recessive cone-rod dystrophy (CRD), an inherited human blindness. In rodent and zebrafish models, the absence of Rab28 results in diminished dawn, photoreceptor, outer segment phagocytosis (OSP). Here, we demonstrate that Rab28 is also required for dusk peaks of OSP, but not for basal OSP levels. This study further elucidated the molecular mechanisms by which Rab28 controls OSP and inherited blindness. Proteomic profiling identified factors whose expression in the eye or whose expression at dawn and dusk peaks of OSP is dysregulated by loss of Rab28. Notably, transgenic overexpression of Rab28, solely in zebrafish cones, rescues the OSP defect in rab28 KO fish, suggesting rab28 gene replacement in cone photoreceptors is sufficient to regulate Rab28-OSP. Rab28 loss also perturbs function of the visual cycle as retinoid levels of 11-cRAL, 11cRP, and atRP are significantly reduced in larval and adult rab28 KO retinae (p < .05). These data give further understanding on the molecular mechanisms of RAB28-associated CRD, highlighting roles of Rab28 in both peaks of OSP, in vitamin A metabolism and in retinoid recycling.
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Affiliation(s)
- Ailís L. Moran
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland
- UCD Conway InstituteUniversity College DublinDublinIreland
| | - Stephen P. Carter
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland
- UCD Conway InstituteUniversity College DublinDublinIreland
| | - Joanna J. Kaylor
- Department of OphthalmologyDavid Geffen School of MedicineUCLA Stein Eye InstituteUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Zhichun Jiang
- Department of OphthalmologyDavid Geffen School of MedicineUCLA Stein Eye InstituteUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Sanne Broekman
- Department of OtorhinolaryngologyRadboud University Medical CenterNijmegenThe Netherlands
- Donders Institute for Brain, Cognition, and BehaviorNijmegenThe Netherlands
| | | | - Alicia Gómez Sánchez
- UCD Conway InstituteUniversity College DublinDublinIreland
- Ocupharm Diagnostic Group ResearchFaculty of Optic and OptometryUniversidad Complutense de MadridMadridSpain
| | - Sajal K. Minhas
- UCD School of Mathematics & StatisticsUniversity College DublinDublinIreland
| | - Erwin van Wijk
- Department of OtorhinolaryngologyRadboud University Medical CenterNijmegenThe Netherlands
- Donders Institute for Brain, Cognition, and BehaviorNijmegenThe Netherlands
| | - Roxana A. Radu
- Department of OphthalmologyDavid Geffen School of MedicineUCLA Stein Eye InstituteUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Gabriel H. Travis
- Department of OphthalmologyDavid Geffen School of MedicineUCLA Stein Eye InstituteUniversity of California Los AngelesLos AngelesCaliforniaUSA
- Department of Biological ChemistryUniversity of CaliforniaLos Angeles School of MedicineLos AngelesCaliforniaUSA
| | - Michelle Carey
- UCD School of Mathematics & StatisticsUniversity College DublinDublinIreland
| | - Oliver E. Blacque
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland
- UCD Conway InstituteUniversity College DublinDublinIreland
| | - Breandán N. Kennedy
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland
- UCD Conway InstituteUniversity College DublinDublinIreland
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Dahl TM, Reed M, Gerstner CD, Baehr W. Conditional Deletion of Cytoplasmic Dynein Heavy Chain in Postnatal Photoreceptors. Invest Ophthalmol Vis Sci 2021; 62:23. [PMID: 34807236 PMCID: PMC8626856 DOI: 10.1167/iovs.62.14.23] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Purpose Cytoplasmic dynein-1 (henceforth dynein) moves cargo in conjunction with dynactin toward the minus end of microtubules. The dynein heavy chain, DYNC1H1, comprises the backbone of dynein, a retrograde motor. Deletion of Dync1h1 abrogates dynein function. The purpose of this communication is to demonstrate effects of photoreceptor dynein inactivation during late postnatal development and in adult retina. Methods We mated Dync1h1F/F mice with iCre75 and Prom1-CreERT2 mice to generate conditional rod and tamoxifen-induced knockout in rods and cones, respectively. We documented retina degeneration with confocal microscopy at postnatal day (P) 10 to P30 for the iCre75 line and 1 to 4 weeks post tamoxifen induction (wPTI) for the Prom1-CreERT2 line. We performed scotopic and photopic electroretinography (ERG) at P16 to P30 in the iCre75 line and at 1-week increments in the Prom1-CreERT2 line. Results were evaluated statistically using Student's t-test, two-factor ANOVA, and Welch's ANOVA. Results Cre-induced homologous recombination of Dync1h1F/F mice truncated DYNC1H1 after exon 23. rodDync1h1-/- photoreceptors degenerated after P14, reducing outer nuclear layer (ONL) thickness and combined inner segment/outer segment (IS/OS) length significantly by P18. Scotopic ERG a-wave amplitudes decreased by P16 and were extinguished at P30. Cones were stable under rod-knockout conditions until P21 but inactive at P30. In tamDync1h1-/- photoreceptors, the IS/OS began shortening by 3wPTI and were nearly eliminated by 4wPTI. The ONL shrank significantly over this interval, indicating rapid photoreceptor degeneration following the loss of dynein. Conclusions Our results demonstrate dynein is essential for the secretory pathway, formation of outer segments, and photoreceptor maintenance.
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Affiliation(s)
- Tiffanie M Dahl
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, United States
| | - Michelle Reed
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, United States
| | - Cecilia D Gerstner
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, United States
| | - Wolfgang Baehr
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, United States.,Department of Neurobiology & Anatomy, University of Utah, Salt Lake City, Utah, United States.,Department of Biology, University of Utah, Salt Lake City, Utah, United States
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11
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Yang J, Zou T, Yang F, Zhang Z, Sun C, Yang Z, Zhang H. A quick protocol for the preparation of mouse retinal cryosections for immunohistochemistry. Open Biol 2021; 11:210076. [PMID: 34315273 PMCID: PMC8316803 DOI: 10.1098/rsob.210076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Immunohistochemistry (IHC) using mouse retinal cryosections is widely used to study the expression and intracellular localization of proteins in mouse retinas. Conventionally, the preparation of retinal cryosections from mice involves tissue fixation, cryoprotection, the removal of the cornea and lens, embedding and sectioning. The procedure takes 1-2 days to complete. Recently, we developed a new technique for the preparation of murine retinal cryosections by coating the sclera with a layer of Super Glue. This enables us to remove the cornea and extract the lens from the unfixed murine eye without causing the eyecup to collapse. In the present study, based on this new technique, we move a step forward to modify the conventional protocol. Unlike in the conventional protocol, in this method, we first coat the unfixed mouse eyeball on the sclera with Super Glue and then remove the cornea and lens. The eyecup is then fixed, cryoprotected and sectioned. This new protocol for the preparation of retinal cryosections reduces the time for the procedure to as little as 2 h. Importantly, the new protocol consistently improves the morphology of retinal sections as well as the image quality of IHC. Thus, this new quick protocol will be greatly beneficial to the community of visual sciences by expediting research progress and improving the results of IHC.
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Affiliation(s)
- Jialiang Yang
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Institute of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
| | - Tongdan Zou
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Institute of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
| | - Fang Yang
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Institute of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
| | - Zilong Zhang
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Institute of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
| | - Chen Sun
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, People's Republic of China
| | - Zhenglin Yang
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Institute of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China.,Institute of Chengdu Biology, Sichuan Translational Medicine Hospital, Chinese Academy of Sciences, Chengdu, Sichuan, People's Republic of China.,Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, People's Republic of China
| | - Houbin Zhang
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Institute of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China.,Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, People's Republic of China
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12
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Georgiou M, Fujinami K, Michaelides M. Inherited retinal diseases: Therapeutics, clinical trials and end points-A review. Clin Exp Ophthalmol 2021; 49:270-288. [PMID: 33686777 DOI: 10.1111/ceo.13917] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/22/2021] [Accepted: 03/01/2021] [Indexed: 12/18/2022]
Abstract
Inherited retinal diseases (IRDs) are a clinically and genetically heterogeneous group of disorders characterised by photoreceptor degeneration or dysfunction. These disorders typically present with severe vision loss that can be progressive, with disease onset ranging from congenital to late adulthood. The advances in genetics, retinal imaging and molecular biology, have conspired to create the ideal environment for establishing treatments for IRDs, with the first approved gene therapy and the commencement of multiple clinical trials. The scope of this review is to familiarise clinicians and scientists with the current management and the prospects for novel therapies for: (1) macular dystrophies, (2) cone and cone-rod dystrophies, (3) cone dysfunction syndromes, (4) Leber congenital amaurosis, (5) rod-cone dystrophies, (6) rod dysfunction syndromes and (7) chorioretinal dystrophies. We also briefly summarise the investigated end points for the ongoing trials.
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Affiliation(s)
- Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Kaoru Fujinami
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK.,Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
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13
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Dahl TM, Reed M, Gerstner CD, Ying G, Baehr W. Effect of conditional deletion of cytoplasmic dynein heavy chain DYNC1H1 on postnatal photoreceptors. PLoS One 2021; 16:e0248354. [PMID: 33705456 PMCID: PMC7951903 DOI: 10.1371/journal.pone.0248354] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 02/24/2021] [Indexed: 11/19/2022] Open
Abstract
Cytoplasmic dynein (dynein 1), a major retrograde motor of eukaryotic cells, is a 1.4 MDa protein complex consisting of a pair of heavy chains (DYNC1H1) and a set of heterodimeric noncatalytic accessory components termed intermediate, light intermediate and light chains. DYNC1H1 (4644 amino acids) is the dynein backbone encoded by a gene consisting of 77 exons. We generated a floxed Dync1h1 allele that excises exons 24 and 25 and truncates DYNC1H1 during Six3Cre-induced homologous recombination. Truncation results in loss of the motor and microtubule-binding domain. Dync1h1F/F;Six3Cre photoreceptors degenerated rapidly within two postnatal weeks. In the postnatal day 6 (P6) Dync1h1F/F;Six3Cre central retina, outer and inner nuclear layers were severely disorganized and lacked a recognizable outer plexiform layer (OPL). Although the gene was effectively silenced by P6, DYNC1H1 remnants persisted and aggregated together with rhodopsin, PDE6 and centrin-2-positive centrosomes in the outer nuclear layer. As photoreceptor degeneration is delayed in the Dync1h1F/F;Six3Cre retina periphery, retinal lamination and outer segment elongation are in part preserved. DYNC1H1 strongly persisted in the inner plexiform layer (IPL) beyond P16 suggesting lack of clearance of the DYNC1H1 polypeptide. This persistence of DYNC1H1 allows horizontal, rod bipolar, amacrine and ganglion cells to survive past P12. The results show that cytoplasmic dynein is essential for retina lamination, nuclear positioning, vesicular trafficking of photoreceptor membrane proteins and inner/outer segment elaboration.
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Affiliation(s)
- Tiffanie M. Dahl
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, United States of America
| | - Michelle Reed
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, United States of America
| | - Cecilia D. Gerstner
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, United States of America
| | - Guoxin Ying
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, United States of America
| | - Wolfgang Baehr
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, United States of America
- Department of Neurobiology & Anatomy, University of Utah, Salt Lake City, Utah, United States of America
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail:
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14
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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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15
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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: 7] [Impact Index Per Article: 2.3] [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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16
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Chaya T, Furukawa T. Post-translational modification enzymes as key regulators of ciliary protein trafficking. J Biochem 2021; 169:633-642. [PMID: 33681987 PMCID: PMC8423421 DOI: 10.1093/jb/mvab024] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 02/24/2021] [Indexed: 12/14/2022] Open
Abstract
Primary cilia are evolutionarily conserved microtubule-based organelles that protrude from the surface of almost all cell types and decode a variety of extracellular stimuli. Ciliary dysfunction causes human diseases named ciliopathies, which span a wide range of symptoms, such as developmental and sensory abnormalities. The assembly, disassembly, maintenance and function of cilia rely on protein transport systems including intraflagellar transport (IFT) and lipidated protein intraflagellar targeting (LIFT). IFT is coordinated by three multisubunit protein complexes with molecular motors along the ciliary axoneme, while LIFT is mediated by specific chaperones that directly recognize lipid chains. Recently, it has become clear that several post-translational modification enzymes play crucial roles in the regulation of IFT and LIFT. Here, we review our current understanding of the roles of these post-translational modification enzymes in the regulation of ciliary protein trafficking as well as their regulatory mechanisms, physiological significance and involvement in human diseases.
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Affiliation(s)
- Taro Chaya
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| | - Takahisa Furukawa
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
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17
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Li L, Lin Y, Yang F, Zou T, Yang J, Zhang H. An improved method for preparation of mouse retinal cryosections. Eur J Histochem 2020; 64. [PMID: 32880132 PMCID: PMC7477724 DOI: 10.4081/ejh.2020.3154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/24/2020] [Indexed: 12/03/2022] Open
Abstract
Immunohistochemistry using mouse retinal cryosections is a routine assay used in vision research. However, retinal tissues are fragile, and it is difficult to obtain an ideal retinal cryosection. Here, we developed a modified method for preparing retinal cryosection. Super Glue was applied on the surface of the sclera before the cornea and the lens are removed from either the unfixed or PFA-fixed mouse eyeballs. The new methods largely prevented retinal detachment in mouse retinal cryosections. Immunostaining of retinal cryosections derived from PFA-fixed mouse eyes using rod and cone markers yielded high-quality immunofluorescent images. Immunolabeling of retinal cryosections obtained from unfixed mouse eyes using a cilium-specific marker had improved orientations of photoreceptor connecting cilia. This new method substantially improves the morphology and immunostaining results of fixed and unfixed mouse eyes.
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Affiliation(s)
- Ling Li
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Institute of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan.
| | - Yongqiong Lin
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Institute of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan.
| | - Fang Yang
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Institute of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan.
| | - Tongdan Zou
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Institute of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan.
| | - Jialiang Yang
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Institute of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan.
| | - Houbin Zhang
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Institute of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan.
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18
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Fujinami K, Liu X, Ueno S, Mizota A, Shinoda K, Kuniyoshi K, Fujinami-Yokokawa Y, Yang L, Arno G, Pontikos N, Kameya S, Kominami T, Terasaki H, Sakuramoto H, Nakamura N, Kurihara T, Tsubota K, Miyake Y, Yoshiake K, Iwata T, Tsunoda K. RP2-associated retinal disorder in a Japanese cohort: Report of novel variants and a literature review, identifying a genotype-phenotype association. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:675-693. [PMID: 32875684 DOI: 10.1002/ajmg.c.31830] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/28/2020] [Accepted: 07/28/2020] [Indexed: 01/10/2023]
Abstract
The retinitis pigmentosa 2 (RP2) gene is one of the causative genes for X-linked inherited retinal disorder. We characterized the clinical/genetic features of four patients with RP2-associated retinal disorder (RP2-RD) from four Japanese families in a nationwide cohort. A systematic review of RP2-RD in the Japanese population was also performed. All four patients were clinically diagnosed with retinitis pigmentosa (RP). The mean age at examination was 36.5 (10-47) years, and the mean visual acuity in the right/left eye was 1.40 (0.52-2.0)/1.10 (0.52-1.7) in the logarithm of the minimum angle of resolution unit, respectively. Three patients showed extensive retinal atrophy with macular involvement, and one had central retinal atrophy. Four RP2 variants were identified, including two novel missense (p.Ser6Phe, p.Leu189Pro) and two previously reported truncating variants (p.Arg120Ter, p.Glu269CysfsTer3). The phenotypes of two patients with truncating variants were more severe than the phenotypes of two patients with missense variants. A systematic review revealed additional 11 variants, including three missense and eight deleterious (null) variants, and a statistically significant association between phenotype severity and genotype severity was revealed. The clinical and genetic spectrum of RP2-RD was illustrated in the Japanese population, identifying the characteristic features of a severe form of RP with early macular involvement.
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Affiliation(s)
- Kaoru Fujinami
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan.,UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK
| | - Xiao Liu
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan.,Southwest Hospital/Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Shinji Ueno
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Atsushi Mizota
- Department of Ophthalmology, Teikyo University, Tokyo, Japan
| | - Kei Shinoda
- Department of Ophthalmology, Teikyo University, Tokyo, Japan.,Department of Ophthalmology, Saitama Medical University, Moroyama Campus, Saitama, Japan
| | - Kazuki Kuniyoshi
- Department of Ophthalmology, Kindai University Faculty of Medicine, Osaka-Sayama, Japan
| | - Yu Fujinami-Yokokawa
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,UCL Institute of Ophthalmology, London, UK.,Department of Health Policy and Management, Keio University School of Medicine, Tokyo, Japan.,Division of Public Health, Yokokawa Clinic, Suita, Japan
| | - Lizhu Yang
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Gavin Arno
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK.,North East Thames Regional Genetics Service, UCL Great Ormond Street Institute of Child Health, NHS Foundation Trust, London, UK
| | - Nikolas Pontikos
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK
| | - Shuhei Kameya
- Department of Ophthalmology, Nippon Medical School Chiba Hokusoh Hospital, Inzai, Japan
| | - Taro Kominami
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroyuki Sakuramoto
- Department of Ophthalmology, Kindai University Faculty of Medicine, Osaka-Sayama, Japan
| | - Natsuko Nakamura
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Department of Ophthalmology, Teikyo University, Tokyo, Japan.,Department of Ophthalmology, The University of Tokyo, Tokyo, Japan
| | - Toshihide Kurihara
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Kazuo Tsubota
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Yozo Miyake
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Aichi Medical University, Nagakute, Japan.,Next vision, Kobe Eye Center, Kobe, Japan
| | - Kazutoshi Yoshiake
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Takeshi Iwata
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Kazushige Tsunoda
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
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19
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De Silva SR, Arno G, Robson AG, Fakin A, Pontikos N, Mohamed MD, Bird AC, Moore AT, Michaelides M, Webster AR, Mahroo OA. The X-linked retinopathies: Physiological insights, pathogenic mechanisms, phenotypic features and novel therapies. Prog Retin Eye Res 2020; 82:100898. [PMID: 32860923 DOI: 10.1016/j.preteyeres.2020.100898] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 08/07/2020] [Accepted: 08/21/2020] [Indexed: 02/08/2023]
Abstract
X-linked retinopathies represent a significant proportion of monogenic retinal disease. They include progressive and stationary conditions, with and without syndromic features. Many are X-linked recessive, but several exhibit a phenotype in female carriers, which can help establish diagnosis and yield insights into disease mechanisms. The presence of affected carriers can misleadingly suggest autosomal dominant inheritance. Some disorders (such as RPGR-associated retinopathy) show diverse phenotypes from variants in the same gene and also highlight limitations of current genetic sequencing methods. X-linked disease frequently arises from loss of function, implying potential for benefit from gene replacement strategies. We review X-inactivation and X-linked inheritance, and explore burden of disease attributable to X-linked genes in our clinically and genetically characterised retinal disease cohort, finding correlation between gene transcript length and numbers of families. We list relevant genes and discuss key clinical features, disease mechanisms, carrier phenotypes and novel experimental therapies. We consider in detail the following: RPGR (associated with retinitis pigmentosa, cone and cone-rod dystrophy), RP2 (retinitis pigmentosa), CHM (choroideremia), RS1 (X-linked retinoschisis), NYX (complete congenital stationary night blindness (CSNB)), CACNA1F (incomplete CSNB), OPN1LW/OPN1MW (blue cone monochromacy, Bornholm eye disease, cone dystrophy), GPR143 (ocular albinism), COL4A5 (Alport syndrome), and NDP (Norrie disease and X-linked familial exudative vitreoretinopathy (FEVR)). We use a recently published transcriptome analysis to explore expression by cell-type and discuss insights from electrophysiology. In the final section, we present an algorithm for genes to consider in diagnosing males with non-syndromic X-linked retinopathy, summarise current experimental therapeutic approaches, and consider questions for future research.
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Affiliation(s)
- Samantha R De Silva
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Gavin Arno
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony G Robson
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Ana Fakin
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Ljubljana University Medical Centre, Ljubljana, Slovenia
| | - Nikolas Pontikos
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Moin D Mohamed
- Department of Ophthalmology, Guy's & St Thomas' NHS Foundation Trust, London, UK
| | - Alan C Bird
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Department of Ophthalmology, UCSF School of Medicine, San Francisco, CA, USA
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Andrew R Webster
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Omar A Mahroo
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Department of Ophthalmology, Guy's & St Thomas' NHS Foundation Trust, London, UK; Section of Ophthalmology, King's College London, UK; Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
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20
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Lane A, Jovanovic K, Shortall C, Ottaviani D, Panes AB, Schwarz N, Guarascio R, Hayes MJ, Palfi A, Chadderton N, Farrar GJ, Hardcastle AJ, Cheetham ME. Modeling and Rescue of RP2 Retinitis Pigmentosa Using iPSC-Derived Retinal Organoids. Stem Cell Reports 2020; 15:67-79. [PMID: 32531192 PMCID: PMC7363745 DOI: 10.1016/j.stemcr.2020.05.007] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 05/13/2020] [Accepted: 05/13/2020] [Indexed: 12/18/2022] Open
Abstract
RP2 mutations cause a severe form of X-linked retinitis pigmentosa (XLRP). The mechanism of RP2-associated retinal degeneration in humans is unclear, and animal models of RP2 XLRP do not recapitulate this severe phenotype. Here, we developed gene-edited isogenic RP2 knockout (RP2 KO) induced pluripotent stem cells (iPSCs) and RP2 patient-derived iPSC to produce 3D retinal organoids as a human retinal disease model. Strikingly, the RP2 KO and RP2 patient-derived organoids showed a peak in rod photoreceptor cell death at day 150 (D150) with subsequent thinning of the organoid outer nuclear layer (ONL) by D180 of culture. Adeno-associated virus-mediated gene augmentation with human RP2 rescued the degeneration phenotype of the RP2 KO organoids, to prevent ONL thinning and restore rhodopsin expression. Notably, these data show that 3D retinal organoids can be used to model photoreceptor degeneration and test potential therapies to prevent photoreceptor cell death.
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Affiliation(s)
| | | | - Ciara Shortall
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | | | | | | | | | | | - Arpad Palfi
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Naomi Chadderton
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - G Jane Farrar
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland.
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21
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Collin GB, Gogna N, Chang B, Damkham N, Pinkney J, Hyde LF, Stone L, Naggert JK, Nishina PM, Krebs MP. Mouse Models of Inherited Retinal Degeneration with Photoreceptor Cell Loss. Cells 2020; 9:cells9040931. [PMID: 32290105 PMCID: PMC7227028 DOI: 10.3390/cells9040931] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/05/2020] [Accepted: 04/07/2020] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal degeneration (RD) leads to the impairment or loss of vision in millions of individuals worldwide, most frequently due to the loss of photoreceptor (PR) cells. Animal models, particularly the laboratory mouse, have been used to understand the pathogenic mechanisms that underlie PR cell loss and to explore therapies that may prevent, delay, or reverse RD. Here, we reviewed entries in the Mouse Genome Informatics and PubMed databases to compile a comprehensive list of monogenic mouse models in which PR cell loss is demonstrated. The progression of PR cell loss with postnatal age was documented in mutant alleles of genes grouped by biological function. As anticipated, a wide range in the onset and rate of cell loss was observed among the reported models. The analysis underscored relationships between RD genes and ciliary function, transcription-coupled DNA damage repair, and cellular chloride homeostasis. Comparing the mouse gene list to human RD genes identified in the RetNet database revealed that mouse models are available for 40% of the known human diseases, suggesting opportunities for future research. This work may provide insight into the molecular players and pathways through which PR degenerative disease occurs and may be useful for planning translational studies.
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Affiliation(s)
- Gayle B. Collin
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Navdeep Gogna
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Bo Chang
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Nattaya Damkham
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Jai Pinkney
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lillian F. Hyde
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lisa Stone
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Jürgen K. Naggert
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Patsy M. Nishina
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
| | - Mark P. Krebs
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
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22
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Powell L, Samarakoon YH, Ismail S, Sayer JA. ARL3, a small GTPase with a functionally conserved role in primary cilia and immune synapses. Small GTPases 2019; 12:167-176. [PMID: 31826708 DOI: 10.1080/21541248.2019.1703466] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The primary cilium and the immunological synapse are both specialized functional plasma membrane domains that share several similarities. Signalling output of membrane domains is regulated, spatially and temporally, by segregating and focusing lipids and proteins. ARL3, a small GTPase, plays a major role in concentrating lipid-modified proteins in both the immunological synapse and the primary cilia. Here in this review we will introduce the role of ARL3 in health and disease and its role in polarizing signalling at the primary cilia and immunological synapses.
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Affiliation(s)
- Laura Powell
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, International Centre for Life, Newcastle upon Tyne, UK
| | - Youhani H Samarakoon
- Spatial segregation of signalling Lab, Beatson Institute for Cancer Research, Glasgow, UK.,Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - Shehab Ismail
- Spatial segregation of signalling Lab, Beatson Institute for Cancer Research, Glasgow, UK.,Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - John A Sayer
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, International Centre for Life, Newcastle upon Tyne, UK.,Renal Services, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK.,NIHR Newcastle Biomedical Research Centre, Newcastle upon Tyne, UK
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23
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Qu L, Pan C, He SM, Lang B, Gao GD, Wang XL, Wang Y. The Ras Superfamily of Small GTPases in Non-neoplastic Cerebral Diseases. Front Mol Neurosci 2019; 12:121. [PMID: 31213978 PMCID: PMC6555388 DOI: 10.3389/fnmol.2019.00121] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/25/2019] [Indexed: 12/22/2022] Open
Abstract
The small GTPases from the Ras superfamily play crucial roles in basic cellular processes during practically the entire process of neurodevelopment, including neurogenesis, differentiation, gene expression, membrane and protein traffic, vesicular trafficking, and synaptic plasticity. Small GTPases are key signal transducing enzymes that link extracellular cues to the neuronal responses required for the construction of neuronal networks, as well as for synaptic function and plasticity. Different subfamilies of small GTPases have been linked to a number of non-neoplastic cerebral diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), intellectual disability, epilepsy, drug addiction, Huntington’s disease (HD), amyotrophic lateral sclerosis (ALS) and a large number of idiopathic cerebral diseases. Here, we attempted to make a clearer illustration of the relationship between Ras superfamily GTPases and non-neoplastic cerebral diseases, as well as their roles in the neural system. In future studies, potential treatments for non-neoplastic cerebral diseases which are based on small GTPase related signaling pathways should be explored further. In this paper, we review all the available literature in support of this possibility.
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Affiliation(s)
- Liang Qu
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China
| | - Chao Pan
- Beijing Institute of Biotechnology, Beijing, China
| | - Shi-Ming He
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China.,Department of Neurosurgery, Xi'an International Medical Center, Xi'an, China
| | - Bing Lang
- The School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom.,Department of Psychiatry, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Guo-Dong Gao
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China
| | - Xue-Lian Wang
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China
| | - Yuan Wang
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China
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24
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Hanke-Gogokhia C, Frederick JM, Zhang H, Baehr W. Binary Function of ARL3-GTP Revealed by Gene Knockouts. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1074:317-325. [PMID: 29721959 DOI: 10.1007/978-3-319-75402-4_39] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
UNC119 and PDEδ are lipid-binding proteins and are thought to form diffusible complexes with transducin-α and prenylated OS proteins, respectively, to mediate their trafficking to photoreceptor outer segments. Here, we investigate mechanisms of trafficking which are controlled by Arf-like protein 3 (Arl3), a small GTPase. The activity of ARL3 is regulated by a GEF (ARL13b) and a GAP (RP2). In a mouse germline knockout of RP2, ARL3-GTP is abundant as its intrinsic GTPase activity is extremely low. High levels of ARL3-GTP impair binding and trafficking of cargo to the outer segment. Germline knockout of ARL3 is embryonically lethal generating a syndromic ciliopathy-like phenotype. Retina- and rod-specific knockout of ARL3 allow to determine the precise mechanisms leading to photoreceptor degeneration. The knockouts reveal binary functions of ARL3-GTP as a key molecule in late-stage photoreceptor ciliogenesis and cargo displacement factor.
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Affiliation(s)
- Christin Hanke-Gogokhia
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT, USA. .,Department of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
| | - Jeanne M Frederick
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Houbin Zhang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Institute of Laboratory Medicine, Hospital of University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China.,School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Wolfgang Baehr
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT, USA. .,Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT, USA. .,Department of Biology, University of Utah, Salt Lake City, UT, USA.
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25
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A novel RP2 missense mutation Q158P identified in an X-linked retinitis pigmentosa family impaired RP2 protein stability. Gene 2019; 707:86-92. [PMID: 31071385 DOI: 10.1016/j.gene.2019.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 04/19/2019] [Accepted: 05/03/2019] [Indexed: 12/23/2022]
Abstract
Retinitis pigmentosa (RP) is the most common form of inherited retinal degenerative diseases. X-linked RP accounts for nearly 15% of all RP cases. In this study, we identified a novel RP2 missense mutation Q158P in a Chinese XLRP family. The RP2 Q158P mutation located in the RP2 TBCC domain and obviously destabilized RP2 protein in ARPE-19 cells. The proteasome inhibitor MG132 could restore the RP2 Q158P protein levels. Meanwhile, lower doses of bortezomib and carfilzomib, another two proteasome inhibitors that have been approved in multiple myeloma clinical therapy, also could rescue the RP2 Q158P protein levels. The ubiquitination of RP2 Q158P protein obviously increased when compared with wild type RP2 protein. Our findings broadened the spectrum of RP2 mutations and may contribute a better understanding of the molecular mechanism of XLRP.
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26
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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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27
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Hanke-Gogokhia C, Chiodo VA, Hauswirth WW, Frederick JM, Baehr W. Rescue of cone function in cone-only Nphp5 knockout mouse model with Leber congenital amaurosis phenotype. Mol Vis 2018; 24:834-846. [PMID: 30713422 PMCID: PMC6334983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 12/28/2018] [Indexed: 11/09/2022] Open
Abstract
Purpose Recessive mutations in the human IQCB1/NPHP5 gene are associated with Senior-Løken syndrome (SLS), a ciliopathy presenting with nephronophthisis and Leber congenital amaurosis (LCA). Nphp5-knockout mice develop LCA without nephronophthisis. Mutant rods rapidly degenerate while mutant cones survive for months. The purpose of this study was to reinitiate cone ciliogenesis in a Nphp5 -/-; Nrl -/- mouse with viral expression of full-length NPHP5 and rescue function. Methods Nphp5 -/- mice were mated with Nrl -/- mice to generate Nphp5-/-; Nrl-/- double-knockouts. Nphp5-/-; Nrl-/- mice and Nphp5+/-; Nrl-/- controls were phenotyped with confocal microscopy from postnatal day 10 (P10) until 6 months of age. Nphp5-/-; Nrl-/- mice and Nphp5+/-; Nrl-/- controls were injected at P15 with self-complementary adenoassociated virus 8 (Y733F) (AAV8(Y733F)) expressing GRK1-FL-cNPHP5. Expression of mutant NPHP5 was verified with confocal microscopy and electroretinography (ERG). Results In the Nphp5 -/- and cone-only Nphp5 -/-; Nrl -/- mice, cone outer segments did not form, but mutant cones continued to express cone pigments in the inner segments without obvious signs of cone cell death. The mutant cone outer nuclear layer (ONL) and the inner segments were stable for more than 6 months in the cone-only Nphp5 -/-; Nrl -/- retinas. Viral expression of NPHP5 initiated after eye opening showed that connecting cilia and RP1-positive axonemes were formed. Furthermore, cone pigments and other cone outer segment proteins (cone transducin and cone PDE6) were present in the nascent mutant cone outer segments, and rescued mutant cones exhibited a significant photopic b-wave (30% of Nphp5 +/-; Nrl -/- controls). Conclusions Nphp5-/-; Nrl-/- cones persistently express cone pigments in the inner segments without obvious degeneration, providing an extended duration interval for viral gene expression. Viral expression of full-length NPHP5 initiates ciliogenesis between P15 and P60, and mutant cones are, in part, functional, encouraging future retina gene replacement therapy.
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Affiliation(s)
- Christin Hanke-Gogokhia
- Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, UT
| | - Vince A. Chiodo
- Department of Ophthalmology, University of Florida, Gainesville, FL
| | | | - Jeanne M. Frederick
- Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, UT
| | - Wolfgang Baehr
- Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, UT,Department of Neurobiology and Anatomy, University of Utah Health Science Center, Salt Lake City, UT,Department of Biology, University of Utah, Salt Lake City, UT
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28
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Sokolov M, Yadav RP, Brooks C, Artemyev NO. Chaperones and retinal disorders. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2018; 114:85-117. [PMID: 30635087 DOI: 10.1016/bs.apcsb.2018.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Defects in protein folding and trafficking are a common cause of photoreceptor degeneration, causing blindness. Photoreceptor cells present an unusual challenge to the protein folding and transport machinery due to the high rate of protein synthesis, trafficking and the renewal of the outer segment, a primary cilium that has been modified into a specialized light-sensing compartment. Phototransduction components, such as rhodopsin and cGMP-phosphodiesterase, and multimeric ciliary transport complexes, such as the BBSome, are hotspots for mutations that disrupt proteostasis and lead to the death of photoreceptors. In this chapter, we review recent studies that advance our understanding of the chaperone and transport machinery of phototransduction proteins.
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Affiliation(s)
- Maxim Sokolov
- Department of Ophthalmology, West Virginia University, Morgantown, WV, United States
| | - Ravi P Yadav
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Celine Brooks
- Department of Ophthalmology, West Virginia University, Morgantown, WV, United States
| | - Nikolai O Artemyev
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA, United States.
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29
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Lyraki R, Lokaj M, Soares DC, Little A, Vermeren M, Marsh JA, Wittinghofer A, Hurd T. Characterization of a novel RP2-OSTF1 interaction and its implication for actin remodelling. J Cell Sci 2018; 131:jcs.211748. [PMID: 29361551 DOI: 10.1242/jcs.211748] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 12/21/2017] [Indexed: 11/20/2022] Open
Abstract
Retinitis pigmentosa 2 (RP2) is the causative gene for a form of X-linked retinal degeneration. RP2 was previously shown to have GTPase-activating protein (GAP) activity towards the small GTPase ARL3 via its N-terminus, but the function of the C-terminus remains elusive. Here, we report a novel interaction between RP2 and osteoclast-stimulating factor 1 (OSTF1), an intracellular protein that indirectly enhances osteoclast formation and activity and is a negative regulator of cell motility. Moreover, this interaction is abolished by a human pathogenic mutation in RP2. We utilized a structure-based approach to pinpoint the binding interface to a strictly conserved cluster of residues on the surface of RP2 that spans both the C- and N-terminal domains of the protein, and which is structurally distinct from the ARL3-binding site. In addition, we show that RP2 is a positive regulator of cell motility in vitro, recruiting OSTF1 to the cell membrane and preventing its interaction with the migration regulator Myo1E.
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Affiliation(s)
- Rodanthi Lyraki
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Mandy Lokaj
- Structural Biology Group, Max-Planck Institut für Molekulare Physiologie, Abteilung Strukturelle Biologie, Otto-Hahn-Str. 11, 44227 Dortmund, Germany
| | - Dinesh C Soares
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Abigail Little
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Matthieu Vermeren
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK.,MRC Centre for Inflammation Research, The Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Joseph A Marsh
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Alfred Wittinghofer
- Structural Biology Group, Max-Planck Institut für Molekulare Physiologie, Abteilung Strukturelle Biologie, Otto-Hahn-Str. 11, 44227 Dortmund, Germany
| | - Toby Hurd
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
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30
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Hanke-Gogokhia C, Wu Z, Sharif A, Yazigi H, Frederick JM, Baehr W. The guanine nucleotide exchange factor Arf-like protein 13b is essential for assembly of the mouse photoreceptor transition zone and outer segment. J Biol Chem 2017; 292:21442-21456. [PMID: 29089384 DOI: 10.1074/jbc.ra117.000141] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 10/24/2017] [Indexed: 01/17/2023] Open
Abstract
Arf-like protein 13b (ARL13b) is a small GTPase that functions as a guanosine nucleotide exchange factor (GEF) for ARL3-GDP. ARL13b is located exclusively in photoreceptor outer segments (OS) presumably anchored to discs by palmitoylation, whereas ARL3 is an inner segment cytoplasmic protein. Hypomorphic mutations affecting the ARL13b G-domain inactivate GEF activity and lead to Joubert syndrome (JS) in humans. However, the molecular mechanisms in ARL13b mutation-induced Joubert syndrome, particularly the function of primary cilia, are still incompletely understood. Because Arl13b germline knockouts in mouse are lethal, we generated retina-specific deletions of ARL13b in which ARL3-GTP formation is impaired. In mouse retArl13b-/- central retina at postnatal day 6 (P6) and older, outer segments were absent, thereby preventing trafficking of outer segment proteins to their destination. Ultrastructure of postnatal day 10 (P10) central retArl13b-/- photoreceptors revealed docking of basal bodies to cell membranes, but mature transition zones and disc structures were absent. Deletion of ARL13b in adult mice via tamoxifen-induced Cre/loxP recombination indicated that axonemes gradually shorten and outer segments progressively degenerate. IFT88, essential for anterograde intraflagellar transport (IFT), was significantly reduced at tamArl13b-/- basal bodies, suggesting impairment of intraflagellar transport. AAV2/8 vector-mediated ARL13b expression in the retArl13b-/- retina rescued ciliogenesis.
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Affiliation(s)
- Christin Hanke-Gogokhia
- From the Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, Utah 84132
| | - Zhijian Wu
- NEI, National Institutes of Health, Bethesda, Maryland 20892
| | - Ali Sharif
- From the Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, Utah 84132
| | - Hussein Yazigi
- From the Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, Utah 84132
| | - Jeanne M Frederick
- From the Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, Utah 84132
| | - Wolfgang Baehr
- From the Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, Utah 84132, .,Department of Neurobiology and Anatomy, University of Utah Health Science Center, Salt Lake City, Utah 84132, and.,Department of Biology, University of Utah, Salt Lake City, Utah 84112
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31
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Wang J, Fresquez T, Kandachar V, Deretic D. The Arf GEF GBF1 and Arf4 synergize with the sensory receptor cargo, rhodopsin, to regulate ciliary membrane trafficking. J Cell Sci 2017; 130:3975-3987. [PMID: 29025970 DOI: 10.1242/jcs.205492] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 10/10/2017] [Indexed: 01/05/2023] Open
Abstract
The small GTPase Arf4 and the Arf GTPase-activating protein (GAP) ASAP1 cooperatively sequester sensory receptor cargo into transport carriers targeted to primary cilia, but the input that drives Arf4 activation in this process remains unknown. Here, we show, by using frog retinas and recombinant human proteins, that during the carrier biogenesis from the photoreceptor Golgi/trans-Golgi network (TGN) a functional complex is formed between Arf4, the Arf guanine nucleotide exchange factor (GEF) GBF1 and the light-sensing receptor, rhodopsin. Rhodopsin and Arf4 bind the regulatory N-terminal dimerization and cyclophillin-binding (DCB)-homology upstream of Sec7 (HUS) domain of GBF1. The complex is sensitive to Golgicide A (GCA), a selective inhibitor of GBF1 that accordingly blocks rhodopsin delivery to the cilia, without disrupting the photoreceptor Golgi. The emergence of newly synthesized rhodopsin in the endomembrane system is essential for GBF1-Arf4 complex formation in vivo Notably, GBF1 interacts with the Arf GAP ASAP1 in a GCA-resistant manner. Our findings indicate that converging signals on GBF1 from the influx of cargo into the Golgi/TGN and the feedback from Arf4, combined with input from ASAP1, control Arf4 activation during sensory membrane trafficking to primary cilia.
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Affiliation(s)
- Jing Wang
- Department of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Theresa Fresquez
- Department of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Vasundhara Kandachar
- Department of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Dusanka Deretic
- Department of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, New Mexico 87131, USA .,Cell Biology and Physiology, University of New Mexico, Albuquerque, New Mexico 87131, USA
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32
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Zhang Y, Deng WT, Du W, Zhu P, Li J, Xu F, Sun J, Gerstner CD, Baehr W, Boye SL, Zhao C, Hauswirth WW, Pang JJ. Gene-based Therapy in a Mouse Model of Blue Cone Monochromacy. Sci Rep 2017; 7:6690. [PMID: 28751656 PMCID: PMC5532293 DOI: 10.1038/s41598-017-06982-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 06/14/2017] [Indexed: 02/08/2023] Open
Abstract
Cones are responsible for daylight, central, high acuity and color vision. Three proteins found in human cones, i.e. long-wavelength (L)-, middle-wavelength (M)-, and short-wavelength sensitive (S)-opsins, are responsible for red, green and blue color recognition, respectively. Human blue cone monochromacy (BCM) is characterized by functional loss of both L- and M-cone opsins due to mutations in the OPN1LW/OPN1MW gene cluster on the X chromosome. BCM patients, who rely on their vision from only S-cones and rods, suffer severely reduced visual acuity and impaired color vision. Recent studies show that there is sufficient cone structure remaining in the central fovea of BCM patients to consider AAV-mediated gene augmentation therapy. In contrast, mouse retina has only two opsins, S-opsin and M-opsin, but no L-opsin. We generated an M-opsin knockout mouse (Opn1mw -/-) expressing only S-opsin as a model for human BCM. We show that recombinant M-opsin delivered by AAV5 vectors rescues M-cone function in Opn1mw -/- mice. We also show that AAV delivered M-opsin localizes in the dorsal cone outer segments, and co-localizes with S-opsin in the ventral retina. Our study demonstrates that cones without M-opsin remain viable and respond to gene augmentation therapy, thereby providing proof-of-concept for cone function restoration in BCM patients.
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Affiliation(s)
- Yuxin Zhang
- Ophthalmology, University of Florida, Gainesville, FL, USA
- Department of Ophthalmology, First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Wen-Tao Deng
- Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Wei Du
- Ophthalmology, University of Florida, Gainesville, FL, USA
- Ophthalmology Department of Peking University People's Hospital, Peking University People's Eye Center and Eye Institute, Beijing, China
| | - Ping Zhu
- Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Jie Li
- Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Fan Xu
- Ophthalmology, University of Florida, Gainesville, FL, USA
- Department of Ophthalmology, People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
| | - Jingfen Sun
- Ophthalmology, University of Florida, Gainesville, FL, USA
- Department of Obstetrics and Gynecology, Shanxi Dayi Hospital, Taiyuan, Shanxi Province, China
| | - Cecilia D Gerstner
- Opthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Wolfgang Baehr
- Opthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Sanford L Boye
- Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Chen Zhao
- Department of Ophthalmology, First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China.
- Department of Ophthalmology and Vision Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
| | | | - Ji-Jing Pang
- Ophthalmology, University of Florida, Gainesville, FL, USA.
- Department of Ophthalmology, First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China.
- Xiamen Eye Center of Xiamen University, Xiamen, Fujian, China.
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33
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Disease mechanisms of X-linked retinitis pigmentosa due to RP2 and RPGR mutations. Biochem Soc Trans 2017; 44:1235-1244. [PMID: 27911705 DOI: 10.1042/bst20160148] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 08/16/2016] [Accepted: 08/18/2016] [Indexed: 01/24/2023]
Abstract
Photoreceptor degeneration is the prominent characteristic of retinitis pigmentosa (RP), a heterogeneous group of inherited retinal dystrophies resulting in blindness. Although abnormalities in many pathways can cause photoreceptor degeneration, one of the most important causes is defective protein transport through the connecting cilium, the structure that connects the biosynthetic inner segment with the photosensitive outer segment of the photoreceptors. The majority of patients with X-linked RP have mutations in the retinitis pigmentosa GTPase regulator (RPGR) or RP2 genes, the protein products of which are both components of the connecting cilium and associated with distinct mechanisms of protein delivery to the outer segment. RP2 and RPGR proteins are associated with severe diseases ranging from classic RP to atypical forms. In this short review, we will summarise current knowledge generated by experimental studies and knockout animal models, compare and discuss the prominent hypotheses about the two proteins' functions in retinal cell biology.
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34
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Abstract
Motile and non-motile (primary) cilia are nearly ubiquitous cellular organelles. The dysfunction of cilia causes diseases known as ciliopathies. The number of reported ciliopathies (currently 35) is increasing, as is the number of established (187) and candidate (241) ciliopathy-associated genes. The characterization of ciliopathy-associated proteins and phenotypes has improved our knowledge of ciliary functions. In particular, investigating ciliopathies has helped us to understand the molecular mechanisms by which the cilium-associated basal body functions in early ciliogenesis, as well as how the transition zone functions in ciliary gating, and how intraflagellar transport enables cargo trafficking and signalling. Both basic biological and clinical studies are uncovering novel ciliopathies and the ciliary proteins involved. The assignment of these proteins to different ciliary structures, processes and ciliopathy subclasses (first order and second order) provides insights into how this versatile organelle is built, compartmentalized and functions in diverse ways that are essential for human health.
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35
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Daniele LL, Emran F, Lobo GP, Gaivin RJ, Perkins BD. Mutation of wrb, a Component of the Guided Entry of Tail-Anchored Protein Pathway, Disrupts Photoreceptor Synapse Structure and Function. Invest Ophthalmol Vis Sci 2017; 57:2942-54. [PMID: 27273592 PMCID: PMC4898200 DOI: 10.1167/iovs.15-18996] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
PURPOSE Tail-anchored (TA) proteins contain a single hydrophobic domain at the C-terminus and are posttranslationally inserted into the ER membrane via the GET (guided entry of tail-anchored proteins) pathway. The role of the GET pathway in photoreceptors is unexplored. The goal of this study was to characterize the zebrafish pinball wizard mutant, which disrupts Wrb, a core component of the GET pathway. METHODS Electroretinography, optokinetic response measurements (OKR), immunohistochemistry, and electron microscopy analyses were employed to assess ribbon synapse function, protein expression, and ultrastructure in 5-day-old zebrafish larvae. Expression of wrb was investigated with real-time qRT-PCR and in situ hybridization. RESULTS Mutation of wrb abolished the OKR and greatly diminished the ERG b-wave, but not the a-wave. Ribeye and SV2 were partially mislocalized in both photoreceptors and hair cells of wrb mutants. Fewer contacts were seen between photoreceptors and bipolar cells in wrb-/- mutants. Expression of wrb was observed throughout the nervous system and Wrb localized to the ER and synaptic region of photoreceptors. Morpholino knockdown of the cytosolic ATPase trc40, which targets TA proteins to the ER, also diminished the OKR. Overexpression of wrb fully restored contrast sensitivity in mutants, while overexpression of mutant wrbR73A, which cannot bind Trc40, did not. CONCLUSIONS Proteins Wrb and Trc40 are required for synaptic transmission between photoreceptors and bipolar cells, indicating that TA protein insertion by the TRC pathway is a critical step in ribbon synapse assembly and function.
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Affiliation(s)
- Lauren L Daniele
- Department of Ophthalmic Research Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Farida Emran
- Centre for Research in Neuroscience, McGill University, Montreal, Quebec, Canada
| | - Glenn P Lobo
- 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
| | - Brian D Perkins
- Department of Ophthalmic Research Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
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36
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May-Simera H, Nagel-Wolfrum K, Wolfrum U. Cilia - The sensory antennae in the eye. Prog Retin Eye Res 2017; 60:144-180. [PMID: 28504201 DOI: 10.1016/j.preteyeres.2017.05.001] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 05/04/2017] [Accepted: 05/08/2017] [Indexed: 12/21/2022]
Abstract
Cilia are hair-like projections found on almost all cells in the human body. Originally believed to function merely in motility, the function of solitary non-motile (primary) cilia was long overlooked. Recent research has demonstrated that primary cilia function as signalling hubs that sense environmental cues and are pivotal for organ development and function, tissue hoemoestasis, and maintenance of human health. Cilia share a common anatomy and their diverse functional features are achieved by evolutionarily conserved functional modules, organized into sub-compartments. Defects in these functional modules are responsible for a rapidly growing list of human diseases collectively termed ciliopathies. Ocular pathogenesis is common in virtually all classes of syndromic ciliopathies, and disruptions in cilia genes have been found to be causative in a growing number of non-syndromic retinal dystrophies. This review will address what is currently known about cilia contribution to visual function. We will focus on the molecular and cellular functions of ciliary proteins and their role in the photoreceptor sensory cilia and their visual phenotypes. We also highlight other ciliated cell types in tissues of the eye (e.g. lens, RPE and Müller glia cells) discussing their possible contribution to disease progression. Progress in basic research on the cilia function in the eye is paving the way for therapeutic options for retinal ciliopathies. In the final section we describe the latest advancements in gene therapy, read-through of non-sense mutations and stem cell therapy, all being adopted to treat cilia dysfunction in the retina.
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Affiliation(s)
- Helen May-Simera
- Institute of Molecular Physiology, Cilia Biology, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Kerstin Nagel-Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany.
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37
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Liu F, Qin Y, Yu S, Soares DC, Yang L, Weng J, Li C, Gao M, Lu Z, Hu X, Liu X, Jiang T, Liu JY, Shu X, Tang Z, Liu M. Pathogenic mutations in retinitis pigmentosa 2 predominantly result in loss of RP2 protein stability in humans and zebrafish. J Biol Chem 2017; 292:6225-6239. [PMID: 28209709 PMCID: PMC5391753 DOI: 10.1074/jbc.m116.760314] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 02/14/2017] [Indexed: 12/20/2022] Open
Abstract
Mutations in retinitis pigmentosa 2 (RP2) account for 10-20% of X-linked retinitis pigmentosa (RP) cases. The encoded RP2 protein is implicated in ciliary trafficking of myristoylated and prenylated proteins in photoreceptor cells. To date >70 mutations in RP2 have been identified. How these mutations disrupt the function of RP2 is not fully understood. Here we report a novel in-frame 12-bp deletion (c.357_368del, p.Pro120_Gly123del) in zebrafish rp2 The mutant zebrafish shows reduced rod phototransduction proteins and progressive retinal degeneration. Interestingly, the protein level of mutant Rp2 is almost undetectable, whereas its mRNA level is near normal, indicating a possible post-translational effect of the mutation. Consistent with this hypothesis, the equivalent 12-bp deletion in human RP2 markedly impairs RP2 protein stability and reduces its protein level. Furthermore, we found that a majority of the RP2 pathogenic mutations (including missense, single-residue deletion, and C-terminal truncation mutations) severely destabilize the RP2 protein. The destabilized RP2 mutant proteins are degraded via the proteasome pathway, resulting in dramatically decreased protein levels. The remaining non-destabilizing mutations T87I, R118H/R118G/R118L/R118C, E138G, and R211H/R211L are suggested to impair the interaction between RP2 and its protein partners (such as ARL3) or with as yet unknown partners. By utilizing a combination of in silico, in vitro, and in vivo approaches, our work comprehensively indicates that loss of RP2 protein structural stability is the predominating pathogenic consequence for most RP2 mutations. Our study also reveals a role of the C-terminal domain of RP2 in maintaining the overall protein stability.
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Affiliation(s)
- Fei Liu
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yayun Qin
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Shanshan Yu
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Dinesh C Soares
- MRC Human Genetics Unit/Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom, and
| | - Lifang Yang
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Jun Weng
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Chang Li
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Meng Gao
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Zhaojing Lu
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xuebin Hu
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xiliang Liu
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Tao Jiang
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Jing Yu Liu
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xinhua Shu
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, United Kingdom
| | - Zhaohui Tang
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Mugen Liu
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China,
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38
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Garcia-Gonzalo FR, Reiter JF. Open Sesame: How Transition Fibers and the Transition Zone Control Ciliary Composition. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a028134. [PMID: 27770015 DOI: 10.1101/cshperspect.a028134] [Citation(s) in RCA: 166] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cilia are plasma membrane protrusions that act as cellular propellers or antennae. To perform these functions, cilia must maintain a composition distinct from those of the contiguous cytosol and plasma membrane. The specialized composition of the cilium depends on the ciliary gate, the region at the ciliary base separating the cilium from the rest of the cell. The ciliary gate's main structural features are electron dense struts connecting microtubules to the adjacent membrane. These structures include the transition fibers, which connect the distal basal body to the base of the ciliary membrane, and the Y-links, which connect the proximal axoneme and ciliary membrane within the transition zone. Both transition fibers and Y-links form early during ciliogenesis and play key roles in ciliary assembly and trafficking. Accordingly, many human ciliopathies are caused by mutations that perturb ciliary gate function.
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Affiliation(s)
- Francesc R Garcia-Gonzalo
- Departamento de Bioquímica, Facultad de Medicina, and Instituto de Investigaciones Biomédicas Alberto Sols UAM-CSIC, Universidad Autónoma de Madrid, 28029 Madrid, Spain
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics, and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California 94158
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39
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Parfitt DA, Lane A, Ramsden C, Jovanovic K, Coffey PJ, Hardcastle AJ, Cheetham ME. Using induced pluripotent stem cells to understand retinal ciliopathy disease mechanisms and develop therapies. Biochem Soc Trans 2016; 44:1245-1251. [PMID: 27911706 PMCID: PMC5238943 DOI: 10.1042/bst20160156] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 07/15/2016] [Accepted: 07/19/2016] [Indexed: 12/23/2022]
Abstract
The photoreceptor cells in the retina have a highly specialised sensory cilium, the outer segment (OS), which is important for detecting light. Mutations in cilia-related genes often result in retinal degeneration. The ability to reprogramme human cells into induced pluripotent stem cells and then differentiate them into a wide range of different cell types has revolutionised our ability to study human disease. To date, however, the challenge of producing fully differentiated photoreceptors in vitro has limited the application of this technology in studying retinal degeneration. In this review, we will discuss recent advances in stem cell technology and photoreceptor differentiation. In particular, the development of photoreceptors with rudimentary OS that can be used to understand disease mechanisms and as an important model to test potential new therapies for inherited retinal ciliopathies.
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Affiliation(s)
- David A. Parfitt
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL UK
| | - Amelia Lane
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL UK
| | - Conor Ramsden
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL UK
| | | | - Peter J. Coffey
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL UK
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40
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Dutta N, Seo S. RPGR, a prenylated retinal ciliopathy protein, is targeted to cilia in a prenylation- and PDE6D-dependent manner. Biol Open 2016; 5:1283-9. [PMID: 27493202 PMCID: PMC5051646 DOI: 10.1242/bio.020461] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
RPGR (retinitis pigmentosa GTPase regulator) is a ciliary protein associated with several forms of inherited retinal degenerative diseases. PDE6D is a ubiquitously expressed prenyl-binding protein and involved in ciliary targeting of prenylated proteins. The current working model for the RPGR function depicts that RPGR acts as a scaffold protein to recruit cargo-loaded PDE6D to primary cilia. Here, we present evidence demonstrating an alternative relationship between RPGR and PDE6D, in which RPGR is a cargo of PDE6D for ciliary targeting. We found that the constitutive isoform of RPGR, which is prenylated, requires prenylation for its ciliary localization. We also found that there are at least two independent ciliary targeting signals in RPGR: one within the N-terminal region that contains the RCC1-like domain and the other near the prenylation site at the C-terminus. Ablation of PDE6D blocked ciliary targeting of RPGR. Our study indicates that prenylated RPGR is one of the cargos of PDE6D for ciliary trafficking and provides insight into the mechanisms by which RPGR is targeted to cilia. Summary: RPGR is a ciliary protein that functions as a scaffold to recruit cargo-loaded PDE6D to cilia. Our study shows that RPGR is also a cargo of PDE6D.
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Affiliation(s)
- Nirmal Dutta
- Department of Ophthalmology and Visual Sciences, University of Iowa College of Medicine, Iowa City, IA 52242, USA
| | - Seongjin Seo
- Department of Ophthalmology and Visual Sciences, University of Iowa College of Medicine, Iowa City, IA 52242, USA
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Ronquillo CC, Hanke-Gogokhia C, Revelo MP, Frederick JM, Jiang L, Baehr W. Ciliopathy-associated IQCB1/NPHP5 protein is required for mouse photoreceptor outer segment formation. FASEB J 2016; 30:3400-3412. [PMID: 27328943 DOI: 10.1096/fj.201600511r] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/14/2016] [Indexed: 12/13/2022]
Abstract
Null mutations in the human IQCB1/NPHP5 (nephrocystin-5) gene that encodes NPHP5 are the most frequent cause of Senior-Løken syndrome, a ciliopathy that is characterized by Leber congenital amaurosis and nephronophthisis. We generated germline Nphp5-knockout mice by placing a β-Geo gene trap in intron 4, thereby truncating NPHP5 at Leu87 and removing all known functional domains. At eye opening, Nphp5-/- mice exhibited absence of scotopic and photopic electroretinogram responses, a phenotype that resembles Leber congenital amaurosis. Outer segment transmembrane protein accumulation in Nphp5-/- endoplasmic reticulum was evident as early as postnatal day (P)6. EGFP-CETN2, a centrosome and transition zone marker, identified basal bodies in Nphp5-/- photoreceptors, but without fully developed transition zones. Ultrastructure of P6 and 10 Nphp5-/- photoreceptors revealed aberrant transition zones of reduced diameter. Nphp5-/- photoreceptor degeneration was complete at 1 mo of age but was delayed significantly in Nphp5-/-;Nrl-/- (cone only) retina. Nphp5-/- mouse embryonic fibroblast developed normal cilia, and Nphp5-/- kidney histology at 1 yr of age showed no significant pathology. Results establish that nephrocystin-5 is essential for photoreceptor outer segment formation but is dispensable for kidney and mouse embryonic fibroblast ciliary formation.-Ronquillo, C. C., Hanke-Gogokhia, C., Revelo, M. P., Frederick, J. M., Jiang, L., Baehr, W. Ciliopathy-associated IQCB1/NPHP5 protein is required for mouse photoreceptor outer segment formation.
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Affiliation(s)
- Cecinio C Ronquillo
- Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, Utah, USA
| | - Christin Hanke-Gogokhia
- Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, Utah, USA; Department of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany
| | - Monica P Revelo
- Department of Pathology, University of Utah, Salt Lake City, Utah, USA
| | - Jeanne M Frederick
- Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, Utah, USA
| | - Li Jiang
- Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, Utah, USA;
| | - Wolfgang Baehr
- Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, Utah, USA; Department of Neurobiology and Anatomy, University of Utah Health Science Center, Salt Lake City, Utah, USA; and Department of Biology, University of Utah, Salt Lake City, Utah, USA
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Dinet V, Ciccotosto GD, Delaunay K, Borras C, Ranchon-Cole I, Kostic C, Savoldelli M, El Sanharawi M, Jonet L, Pirou C, An N, Abitbol M, Arsenijevic Y, Behar-Cohen F, Cappai R, Mascarelli F. Amyloid Precursor-Like Protein 2 deletion-induced retinal synaptopathy related to congenital stationary night blindness: structural, functional and molecular characteristics. Mol Brain 2016; 9:64. [PMID: 27267879 PMCID: PMC4897877 DOI: 10.1186/s13041-016-0245-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 05/30/2016] [Indexed: 12/03/2022] Open
Abstract
Background Amyloid precursor protein knockout mice (APP-KO) have impaired differentiation of amacrine and horizontal cells. APP is part of a gene family and its paralogue amyloid precursor-like protein 2 (APLP2) has both shared as well as distinct expression patterns to APP, including in the retina. Given the impact of APP in the retina we investigated how APLP2 expression affected the retina using APLP2 knockout mice (APLP2-KO). Results Using histology, morphometric analysis with noninvasive imaging technique and electron microscopy, we showed that APLP2-KO retina displayed abnormal formation of the outer synaptic layer, accompanied with greatly impaired photoreceptor ribbon synapses in adults. Moreover, APLP2-KO displayed a significant decease in ON-bipolar, rod bipolar and type 2 OFF-cone bipolar cells (36, 21 and 63 %, respectively). Reduction of the number of bipolar cells was accompanied with disrupted dendrites, reduced expression of metabotropic glutamate receptor 6 at the dendritic tips and alteration of axon terminals in the OFF laminae of the inner plexiform layer. In contrast, the APP-KO photoreceptor ribbon synapses and bipolar cells were intact. The APLP2-KO retina displayed numerous phenotypic similarities with the congenital stationary night blindness, a non-progressive retinal degeneration disease characterized by the loss of night vision. The pathological phenotypes in the APLP2-KO mouse correlated to altered transcription of genes involved in pre- and postsynatic structure/function, including CACNA1F, GRM6, TRMP1 and Gα0, and a normal scotopic a-wave electroretinogram amplitude, markedly reduced scotopic electroretinogram b-wave and modestly reduced photopic cone response. This confirmed the impaired function of the photoreceptor ribbon synapses and retinal bipolar cells, as is also observed in congenital stationary night blindness. Since congenital stationary night blindness present at birth, we extended our analysis to retinal differentiation and showed impaired differentiation of different bipolar cell subtypes and an altered temporal sequence of development from OFF to ON laminae in the inner plexiform layer. This was associated with the altered expression patterns of bipolar cell generation and differentiation factors, including MATH3, CHX10, VSX1 and OTX2. Conclusions These findings demonstrate that APLP2 couples retina development and synaptic genes and present the first evidence that APLP2 expression may be linked to synaptic disease. Electronic supplementary material The online version of this article (doi:10.1186/s13041-016-0245-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Virginie Dinet
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Giuseppe D Ciccotosto
- Department of Pathology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia
| | - Kimberley Delaunay
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Céline Borras
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Isabelle Ranchon-Cole
- Laboratoire de Biophysique Sensorielle, Université Clermont 1, Clermont-Ferrand, France
| | - Corinne Kostic
- Unit of Gene Therapy & Stem Cell Biology, University of Lausanne, Jules-Gonin Eye Hospital, Lausanne, Switzerland
| | - Michèle Savoldelli
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Mohamed El Sanharawi
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Laurent Jonet
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Caroline Pirou
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Na An
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Marc Abitbol
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Yvan Arsenijevic
- Unit of Gene Therapy & Stem Cell Biology, University of Lausanne, Jules-Gonin Eye Hospital, Lausanne, Switzerland
| | - Francine Behar-Cohen
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Roberto Cappai
- Department of Pathology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia
| | - Frédéric Mascarelli
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France.
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Wright ZC, Singh RK, Alpino R, Goldberg AFX, Sokolov M, Ramamurthy V. ARL3 regulates trafficking of prenylated phototransduction proteins to the rod outer segment. Hum Mol Genet 2016; 25:2031-2044. [PMID: 26936825 PMCID: PMC5062590 DOI: 10.1093/hmg/ddw077] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 02/01/2016] [Accepted: 02/29/2016] [Indexed: 12/31/2022] Open
Abstract
The small GTPase, ADP-ribosylation factor-like 3 (ARL3), has been proposed to participate in the transport of proteins in photoreceptor cells. Moreover, it has been implicated in the pathogenesis associated with X-linked retinitis pigmentosa (XLRP) resulting from mutations in the ARL3 GTPase activating protein, retinitis pigmentosa 2 (RP2). To determine the importance of ARL3 in rod photoreceptor cells, we generated transgenic mice expressing a dominant active form of ARL3 (ARL3-Q71L) under a rod-specific promoter. ARL3-Q71L animals exhibited extensive rod cell death after post-natal day 30 (PN30) and degeneration was complete by PN70. Prior to the onset of cell death, rod photoresponse was significantly reduced along with a robust decrease in rod phosphodiesterase 6 (PDE6) and G-protein receptor kinase-1 (GRK1) levels. Furthermore, assembled phosphodiesterase-6 (PDE6) subunits, rod transducin and G-protein receptor kinase-1 (GRK1) accumulated on large punctate structures within the inner segment in ARL3-Q71L retina. Defective trafficking of prenylated proteins is likely due to sequestration of prenyl binding protein δ (PrBPδ) by ARL3-Q71L as we demonstrate a specific interaction between these proteins in the retina. Unexpectedly, our studies also revealed a novel role for ARL3 in the migration of photoreceptor nuclei. In conclusion, this study identifies ARL3 as a key player in prenylated protein trafficking in rod photoreceptor cells and establishes the potential role for ARL3 dysregulation in the pathogenesis of RP2-related forms of XLRP.
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Affiliation(s)
| | | | | | | | - Maxim Sokolov
- Department of Ophthalmology, Department of Biochemistry and Center for Neuroscience, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WA 26506, USA and
| | - Visvanathan Ramamurthy
- Department of Ophthalmology, Department of Biochemistry and Center for Neuroscience, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WA 26506, USA and
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Rainy N, Etzion T, Alon S, Pomeranz A, Nisgav Y, Livnat T, Bach M, Gerstner CD, Baehr W, Gothilf Y, Stiebel-Kalish H. Knockdown of unc119c results in visual impairment and early-onset retinal dystrophy in zebrafish. Biochem Biophys Res Commun 2016; 473:1211-1217. [PMID: 27079236 DOI: 10.1016/j.bbrc.2016.04.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 04/09/2016] [Indexed: 12/29/2022]
Abstract
PURPOSE UNC119 proteins are involved in G protein trafficking in mouse retinal photoreceptors and Caenorhabditis elegans olfactory neurons. An Unc119 null allele is associated with cone-rod dystrophy in mouse, but the mechanism leading to disease is not understood. We studied the role of Unc119 paralogs and Arl3l2 in zebrafish vision and retinal organization resulting from unc119c and arl3l2 knockdown. METHODS Zebrafish unc119c was amplified by PCR from retina and pineal gland cDNA. Its expression pattern in the eye and pineal gland was determined by whole-mount in-situ hybridization. unc119c and arl3l2 were knocked down using morpholino-modified oligonucleotides (MO). Their visual function was assessed with a quantitative optomotor assay on 6 days post-fertilization larvae. Retinal morphology was analyzed using immunohistochemistry with anti-cone arrestin (zpr-1) and anti-cone transducin-α (GNAT2) antibodies. RESULTS The zebrafish genome contains four genes encoding unc119 paralogs located on different chromosomes. The exon/intron arrangements of these genes are identical. Three Unc119 paralogs are expressed in the zebrafish retina, termed Unc119a-c. Based on sequence similarity, Unc119a and Unc119b are orthologs of mammalian UNC119a and UNC119b, respectively. A third, Unc119c, is unique and not present in mammals. Whole mount in-situ hybridization revealed that unc119a and unc119b RNA are ubiquitously expressed in the CNS, and unc119c is specifically expressed in photoreceptive tissues (pineal gland and retina). A Unc119 interactant, Arl3l2 also localizes to the pineal gland and the retina. As measured by the optomotor response, unc119c and arl3l2 knockdown resulted in significantly lower vision compared to wild-type zebrafish larvae and control morpholino (MO). Immunohistological analysis with anti-cone transducin and anti-cone arrestin (zpr-1) indicates that knockdown of unc119c leads to photoreceptor degeneration mostly affecting cones. CONCLUSIONS Our results suggest that Unc119c is the only Unc119 paralog that is highly specific to the retina in zebrafish. Unc119c and Arl3l2 proteins are important for the function of cones.
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Affiliation(s)
- Nir Rainy
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Israel
| | - Talya Etzion
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Israel
| | - Shahar Alon
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Israel; Sagol School of Neuroscience Tel Aviv University, Israel
| | - Adi Pomeranz
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Israel
| | - Yael Nisgav
- Laboratory of Eye Research, Felsenstein Medical Research Center Israel, Petah Tikva, Israel
| | - Tami Livnat
- Laboratory of Eye Research, Felsenstein Medical Research Center Israel, Petah Tikva, Israel
| | - Michael Bach
- Eye Center, Medical Center, University of Freiburg, Killianstraße 5, 79106, Freiburg, Germany
| | - Cecilia D Gerstner
- Department of Ophthalmology and Department of Neurobiology and Anatomy, University of Utah Health Science Center, Salt Lake City, UT 84132, USA
| | - Wolfgang Baehr
- Department of Ophthalmology and Department of Neurobiology and Anatomy, University of Utah Health Science Center, Salt Lake City, UT 84132, USA; Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Yoav Gothilf
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Israel; Sagol School of Neuroscience Tel Aviv University, Israel
| | - Hadas Stiebel-Kalish
- Department of Ophthalmology at Rabin Medical Center, Petah Tikva & Sackler Faculty of Medicine, Tel Aviv University, Israel.
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Fansa EK, Kösling SK, Zent E, Wittinghofer A, Ismail S. PDE6δ-mediated sorting of INPP5E into the cilium is determined by cargo-carrier affinity. Nat Commun 2016; 7:11366. [PMID: 27063844 PMCID: PMC5512577 DOI: 10.1038/ncomms11366] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 03/18/2016] [Indexed: 01/06/2023] Open
Abstract
The phosphodiesterase 6 delta subunit (PDE6δ) shuttles several farnesylated cargos between membranes. The cargo sorting mechanism between cilia and other compartments is not understood. Here we show using the inositol polyphosphate 5'-phosphatase E (INPP5E) and the GTP-binding protein (Rheb) that cargo sorting depends on the affinity towards PDE6δ and the specificity of cargo release. High-affinity cargo is exclusively released by the ciliary transport regulator Arl3, while low-affinity cargo is released by Arl3 and its non-ciliary homologue Arl2. Structures of PDE6δ/cargo complexes reveal the molecular basis of the sorting signal which depends on the residues at the -1 and -3 positions relative to farnesylated cysteine. Structure-guided mutation allows the generation of a low-affinity INPP5E mutant which loses exclusive ciliary localization. We postulate that the affinity to PDE6δ and the release by Arl2/3 in addition to a retention signal are the determinants for cargo sorting and enrichment at its destination.
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Affiliation(s)
- Eyad Kalawy Fansa
- Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | | | - Eldar Zent
- Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Alfred Wittinghofer
- Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Shehab Ismail
- CR-UK Beatson Institute, Garscube Estate Switchback Road, Glasgow G61 1BD, UK
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46
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Strom SP, Clark MJ, Martinez A, Garcia S, Abelazeem AA, Matynia A, Parikh S, Sullivan LS, Bowne SJ, Daiger SP, Gorin MB. De Novo Occurrence of a Variant in ARL3 and Apparent Autosomal Dominant Transmission of Retinitis Pigmentosa. PLoS One 2016; 11:e0150944. [PMID: 26964041 PMCID: PMC4786330 DOI: 10.1371/journal.pone.0150944] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 02/22/2016] [Indexed: 11/19/2022] Open
Abstract
Background Retinitis pigmentosa is a phenotype with diverse genetic causes. Due to this genetic heterogeneity, genome-wide identification and analysis of protein-altering DNA variants by exome sequencing is a powerful tool for novel variant and disease gene discovery. In this study, exome sequencing analysis was used to search for potentially causal DNA variants in a two-generation pedigree with apparent dominant retinitis pigmentosa. Methods Variant identification and analysis of three affected members (mother and two affected offspring) was performed via exome sequencing. Parental samples of the index case were used to establish inheritance. Follow-up testing of 94 additional retinitis pigmentosa pedigrees was performed via retrospective analysis or Sanger sequencing. Results and Conclusions A total of 136 high quality coding variants in 123 genes were identified which are consistent with autosomal dominant disease. Of these, one of the strongest genetic and functional candidates is a c.269A>G (p.Tyr90Cys) variant in ARL3. Follow-up testing established that this variant occurred de novo in the index case. No additional putative causal variants in ARL3 were identified in the follow-up cohort, suggesting that if ARL3 variants can cause adRP it is an extremely rare phenomenon.
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Affiliation(s)
- Samuel P. Strom
- Department of Pathology and Laboratory Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
| | - Michael J. Clark
- Personalis Inc., Menlo Park, California, United States of America
| | - Ariadna Martinez
- Department of Cardiology, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Sarah Garcia
- Personalis Inc., Menlo Park, California, United States of America
| | | | - Anna Matynia
- Jules Stein Eye Institute and Department of Ophthalmology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Sachin Parikh
- Jules Stein Eye Institute and Department of Ophthalmology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Lori S. Sullivan
- Human Genetics Center, University of Texas Health Science Center, Houston, Texas, United States of America
| | - Sara J. Bowne
- Human Genetics Center, University of Texas Health Science Center, Houston, Texas, United States of America
| | - Stephen P. Daiger
- Human Genetics Center, University of Texas Health Science Center, Houston, Texas, United States of America
| | - Michael B. Gorin
- Jules Stein Eye Institute and Department of Ophthalmology, University of California Los Angeles, Los Angeles, California, United States of America
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Hanke-Gogokhia C, Wu Z, Gerstner CD, Frederick JM, Zhang H, Baehr W. Arf-like Protein 3 (ARL3) Regulates Protein Trafficking and Ciliogenesis in Mouse Photoreceptors. J Biol Chem 2016; 291:7142-55. [PMID: 26814127 DOI: 10.1074/jbc.m115.710954] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Indexed: 12/22/2022] Open
Abstract
Arf-like protein 3 (ARL3) is a ubiquitous small GTPase expressed in ciliated cells of plants and animals. Germline deletion ofArl3in mice causes multiorgan ciliopathy reminiscent of Bardet-Biedl or Joubert syndromes. As photoreceptors are elegantly compartmentalized and have cilia, we probed the function of ARL3 (ADP-ribosylation factor (Arf)-like 3 protein) by generating rod photoreceptor-specific (prefix(rod)) and retina-specific (prefix(ret))Arl3deletions. In predegenerate(rod)Arl3(-/-)mice, lipidated phototransduction proteins showed trafficking deficiencies, consistent with the role of ARL3 as a cargo displacement factor for lipid-binding proteins. By contrast,(ret)Arl3(-/-)rods and cones expressing Cre recombinase during embryonic development formed neither connecting cilia nor outer segments and degenerated rapidly. Absence of cilia infers participation of ARL3 in ciliogenesis and axoneme formation. Ciliogenesis was rescued, and degeneration was reversed in part by subretinal injection of adeno-associated virus particles expressing ARL3-EGFP. The conditional knock-out phenotypes permitted identification of two ARL3 functions, both in the GTP-bound form as follows: one as a regulator of intraflagellar transport participating in photoreceptor ciliogenesis and the other as a cargo displacement factor transporting lipidated protein to the outer segment. Surprisingly, a farnesylated inositol polyphosphate phosphatase only trafficked from the endoplasmic reticulum to the Golgi, thereby excluding it from a role in photoreceptor cilia physiology.
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Affiliation(s)
- Christin Hanke-Gogokhia
- From the Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, and the Department of Biochemistry and Biology, University of Potsdam, 14476 Potsdam-Golm, Germany
| | - Zhijian Wu
- the NEI, National Institutes of Health, Bethesda, Maryland 20892
| | - Cecilia D Gerstner
- From the Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, and
| | - Jeanne M Frederick
- From the Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, and
| | - Houbin Zhang
- the Sichuan Provincial Key Laboratory for Human Disease Gene Study, Institute of Laboratory Medicine, Hospital of University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, 610072 Sichuan, China, the School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072 Sichuan, China, and
| | - Wolfgang Baehr
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah 84132, From the Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, and the Department of Biology, University of Utah, Salt Lake City, Utah 84112
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Gotthardt K, Lokaj M, Koerner C, Falk N, Gießl A, Wittinghofer A. A G-protein activation cascade from Arl13B to Arl3 and implications for ciliary targeting of lipidated proteins. eLife 2015; 4. [PMID: 26551564 PMCID: PMC4868535 DOI: 10.7554/elife.11859] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 11/06/2015] [Indexed: 12/11/2022] Open
Abstract
Small G-proteins of the ADP-ribosylation-factor-like (Arl) subfamily have been shown to be crucial to ciliogenesis and cilia maintenance. Active Arl3 is involved in targeting and releasing lipidated cargo proteins from their carriers PDE6δ and UNC119a/b to the cilium. However, the guanine nucleotide exchange factor (GEF) which activates Arl3 is unknown. Here we show that the ciliary G-protein Arl13B mutated in Joubert syndrome is the GEF for Arl3, and its function is conserved in evolution. The GEF activity of Arl13B is mediated by the G-domain plus an additional C-terminal helix. The switch regions of Arl13B are involved in the interaction with Arl3. Overexpression of Arl13B in mammalian cell lines leads to an increased Arl3·GTP level, whereas Arl13B Joubert-Syndrome patient mutations impair GEF activity and thus Arl3 activation. We anticipate that through Arl13B's exclusive ciliary localization, Arl3 activation is spatially restricted and thereby an Arl3·GTP compartment generated where ciliary cargo is specifically released.
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Affiliation(s)
- Katja Gotthardt
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Mandy Lokaj
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Carolin Koerner
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Nathalie Falk
- Department of Biology, Animal Physiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Andreas Gießl
- Department of Biology, Animal Physiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Alfred Wittinghofer
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Dortmund, Germany
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Lokaj M, Kösling SK, Koerner C, Lange SM, van Beersum SEC, van Reeuwijk J, Roepman R, Horn N, Ueffing M, Boldt K, Wittinghofer A. The Interaction of CCDC104/BARTL1 with Arl3 and Implications for Ciliary Function. Structure 2015; 23:2122-32. [PMID: 26455799 PMCID: PMC4635315 DOI: 10.1016/j.str.2015.08.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 08/26/2015] [Accepted: 08/29/2015] [Indexed: 01/23/2023]
Abstract
Cilia are small antenna-like cellular protrusions critical for many developmental signaling pathways. The ciliary protein Arl3 has been shown to act as a specific release factor for myristoylated and farnesylated ciliary cargo molecules by binding to the effectors Unc119 and PDE6δ. Here we describe a newly identified Arl3 binding partner, CCDC104/CFAP36. Biochemical and structural analyses reveal that the protein contains a BART-like domain and is called BARTL1. It recognizes an LLxILxxL motif at the N-terminal amphipathic helix of Arl3, which is crucial for the interaction with the BART-like domain but also for the ciliary localization of Arl3 itself. These results seem to suggest a ciliary role of BARTL1, and possibly link it to the Arl3 transport network. We thus speculate on a regulatory mechanism whereby BARTL1 aids the presentation of active Arl3 to its GTPase-activating protein RP2 or hinders Arl3 membrane binding in the area of the transition zone.
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Affiliation(s)
- Mandy Lokaj
- Max-Planck-Institute of Molecular Physiology, Emeritus Group, Otto-Hahn-Straße 15, 44227 Dortmund, Germany
| | - Stefanie K Kösling
- Max-Planck-Institute of Molecular Physiology, Emeritus Group, Otto-Hahn-Straße 15, 44227 Dortmund, Germany
| | - Carolin Koerner
- Max-Planck-Institute of Molecular Physiology, Emeritus Group, Otto-Hahn-Straße 15, 44227 Dortmund, Germany
| | - Sven M Lange
- Max-Planck-Institute of Molecular Physiology, Emeritus Group, Otto-Hahn-Straße 15, 44227 Dortmund, Germany
| | - Sylvia E C van Beersum
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, the Netherlands
| | - Jeroen van Reeuwijk
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, the Netherlands
| | - Ronald Roepman
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, the Netherlands
| | - Nicola Horn
- Medical Proteome Center, Institute for Ophthalmic Research, University of Tübingen, Nägelestrasse 5, 72074 Tübingen, Germany
| | - Marius Ueffing
- Medical Proteome Center, Institute for Ophthalmic Research, University of Tübingen, Nägelestrasse 5, 72074 Tübingen, Germany
| | - Karsten Boldt
- Medical Proteome Center, Institute for Ophthalmic Research, University of Tübingen, Nägelestrasse 5, 72074 Tübingen, Germany
| | - Alfred Wittinghofer
- Max-Planck-Institute of Molecular Physiology, Emeritus Group, Otto-Hahn-Straße 15, 44227 Dortmund, Germany.
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Li L, Rao KN, Zheng-Le Y, Hurd TW, Lillo C, Khanna H. Loss of retinitis pigmentosa 2 (RP2) protein affects cone photoreceptor sensory cilium elongation in mice. Cytoskeleton (Hoboken) 2015; 72:447-54. [PMID: 26383048 DOI: 10.1002/cm.21255] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 09/11/2015] [Accepted: 09/15/2015] [Indexed: 02/03/2023]
Abstract
Degeneration of photoreceptors (rods and cones) results in blindness. As we rely almost entirely on our daytime vision mediated by the cones, it is the loss of these photoreceptors that results in legal blindness and poor quality of life. Cone dysfunction is usually observed due to two mechanisms: noncell-autonomous due to the secondary effect of rod death if the causative gene is specifically expressed in rods and cell autonomous, if the mutation is in a cone-specific gene. However, it is difficult to dissect cone autonomous effect of mutations in the genes that are expressed in both rods and cones. Here we report a property of murine cone photoreceptors, which is a cone-autonomous effect of the genetic perturbation of the retinitis pigmentosa 2 (Rp2) gene mutated in human X-linked RP. Constitutive loss of Rp2 results in abnormal extension of the cone outer segment (COS). This effect is phenocopied when the Rp2 gene is ablated specifically in cones but not when ablated in rods. Furthermore, the elongated COS exhibits abnormal ultrastructure with disorganized lamellae. Additionally, elongation of both the outer segment membrane and the microtubule cytoskeleton was observed in the absence of RP2. Taken together, our studies identify a cone morphological defect in retinal degeneration due to ablation of RP2 and will assist in understanding cone-autonomous responses during disease and develop targeted therapies.
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Affiliation(s)
- Linjing Li
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Kollu Nageswara Rao
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Yun Zheng-Le
- Department of Medicine, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma
| | | | - Concepción Lillo
- Institute of Neurosciences of Castilla Y León-INCyL, Institute of Biomedical Research of Salamanca-IBSAL, Cell Biology and Pathology, University of Salamanca, Salamanca, Spain
| | - Hemant Khanna
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts
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