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Uwineza A, Cummins I, Jarrin M, Kalligeraki AA, Barnard S, Mol M, Degani G, Altomare AA, Aldini G, Schreurs A, Balschun D, Ainsbury EA, Dias IHK, Quinlan RA. Identification and quantification of ionising radiation-induced oxysterol formation in membranes of lens fibre cells. ADVANCES IN REDOX RESEARCH 2023; 7:None. [PMID: 38798747 PMCID: PMC11112148 DOI: 10.1016/j.arres.2022.100057] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 12/06/2022] [Accepted: 12/13/2022] [Indexed: 05/29/2024]
Abstract
Ionising radiation (IR) is a cause of lipid peroxidation, and epidemiological data have revealed a correlation between exposure to IR and the development of eye lens cataracts. Cataracts remain the leading cause of blindness around the world. The plasma membranes of lens fibre cells are one of the most cholesterolrich membranes in the human body, forming lipid rafts and contributing to the biophysical properties of lens fibre plasma membrane. Liquid chromatography followed by mass spectrometry was used to analyse bovine eye lens lipid membrane fractions after exposure to 5 and 50 Gy and eye lenses taken from wholebody 2 Gy-irradiated mice. Although cholesterol levels do not change significantly, IR dose-dependant formation of the oxysterols 7β-hydroxycholesterol, 7-ketocholesterol and 5, 6-epoxycholesterol in bovine lens nucleus membrane extracts was observed. Whole-body X-ray exposure (2 Gy) of 12-week old mice resulted in an increase in 7β-hydroxycholesterol and 7-ketocholesterol in their eye lenses. Their increase regressed over 24 h in the living lens cortex after IR exposure. This study also demonstrated that the IR-induced fold increase in oxysterols was greater in the mouse lens cortex than the nucleus. Further work is required to elucidate the mechanistic link(s) between oxysterols and IR-induced cataract, but these data evidence for the first time that IR exposure of mice results in oxysterol formation in their eye lenses.
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Affiliation(s)
- Alice Uwineza
- Department of Biosciences, University of Durham, Upper Mountjoy Science Site, South Road, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, University of Durham, South Road, Durham D1 3LE, United Kingdom
| | - Ian Cummins
- Department of Biosciences, University of Durham, Upper Mountjoy Science Site, South Road, Durham DH1 3LE, United Kingdom
| | - Miguel Jarrin
- Department of Biosciences, University of Durham, Upper Mountjoy Science Site, South Road, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, University of Durham, South Road, Durham D1 3LE, United Kingdom
| | - Alexia A. Kalligeraki
- Department of Biosciences, University of Durham, Upper Mountjoy Science Site, South Road, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, University of Durham, South Road, Durham D1 3LE, United Kingdom
| | - Stephen Barnard
- Department of Biosciences, University of Durham, Upper Mountjoy Science Site, South Road, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, University of Durham, South Road, Durham D1 3LE, United Kingdom
- UK Health Security Agency, Cytogenetics and Pathology Group, Centre for Radiation, Chemical and Environmental Hazards Division, Chilton, Oxon OX11 0RQ, Didcot, United Kingdom
| | - Marco Mol
- Department of Pharmaceutical Sciences, Via Mangiagalli 25, Milano 20133, Italy
| | - Genny Degani
- Department of Biosciences, Via Celoria 26, Milano 20133, Italy
| | | | - Giancarlo Aldini
- Department of Pharmaceutical Sciences, Via Mangiagalli 25, Milano 20133, Italy
| | - An Schreurs
- Brain & Cognition, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Detlef Balschun
- Brain & Cognition, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Elizabeth A. Ainsbury
- UK Health Security Agency, Cytogenetics and Pathology Group, Centre for Radiation, Chemical and Environmental Hazards Division, Chilton, Oxon OX11 0RQ, Didcot, United Kingdom
| | - Irundika HK Dias
- Aston Medical School, Aston University, B4 7ET, Birmingham, United Kingdom
| | - Roy A. Quinlan
- Department of Biosciences, University of Durham, Upper Mountjoy Science Site, South Road, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, University of Durham, South Road, Durham D1 3LE, United Kingdom
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, United States
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2
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Dvaladze A, Tavares E, Di Scipio M, Nimmo G, Grudzinska-Pechhacker MK, Paton T, Tumber A, Li S, Eileen C, Ertl-Wagner B, Mamak E, Hoffmann G, Marshall CR, Haas D, Mayatepek E, Schulze A, Heon E, Vincent A. Deep Intronic Variant in MVK as a Cause for Mevalonic Aciduria Initially Presenting as Non-syndromic Retinitis Pigmentosa. Clin Genet 2022; 102:524-529. [PMID: 35916082 DOI: 10.1111/cge.14207] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 07/25/2022] [Accepted: 07/27/2022] [Indexed: 11/29/2022]
Abstract
Non-syndromic retinitis pigmentosa (NSRP) is a clinically and genetically heterogeneous group of disorders characterized by progressive degeneration of the rod and cone photoreceptors, often leading to blindness. The evolving association of syndromic genes to cause NSRP and the increasing role of intronic variants in explaining missing heritability in genetic disorders present challenges in establishing conclusive clinical and genetic diagnoses. This study sought to identify and validate the causative genetic variant(s) in a 13-year-old male initially diagnosed with NSRP. Genome sequencing identified a pathogenic missense variant in MVK [NM_000431.3:c.803T>C (p. Ile268Thr)], in trans with a novel intronic variant predicted to create a new donor splice site (c.768+71C>A). Proband cDNA analysis confirmed the inclusion of the first 68 base pairs of intron 8 that resulted in a frameshift in MVK (r.768_769ins[768+1_768+68]) and significantly reduced the expression of reference transcript (17.6%). Patient re-phenotyping revealed ataxia, cerebellar atrophy, elevated urinary mevalonate and LTE4 , in keeping with mild mevalonic aciduria and associated syndromic retinitis pigmentosa. Leakage of reference transcript likely explains the milder phenotype observed. This is the first association of a deep intronic splice variant to cause MVK-related disorder. This report highlights the importance of variant validation and patient re-phenotyping in establishing accurate diagnosis in the era of genome sequencing.
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Affiliation(s)
- Anna Dvaladze
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada
| | - Erika Tavares
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada
| | - Matteo Di Scipio
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada
| | - Graeme Nimmo
- Clinical and Metabolic Genetics, HSC, Canada.,Fred A Litwin Family Centre for Genetic Medicine, The University Health Network, Toronto, Canada
| | - Monika K Grudzinska-Pechhacker
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada.,Department of Ophthalmology and Vision Sciences, HSC and University of Toronto, Canada
| | - Tara Paton
- The Centre for Applied Genomics, HSC, Canada
| | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, HSC and University of Toronto, Canada
| | - Shuning Li
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada
| | - Christabel Eileen
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada
| | - Birgit Ertl-Wagner
- Division of Neuroradiology, HSC, Canada.,Department of Medical Imaging, University of Toronto, Canada
| | - Eva Mamak
- Department of Psychology, HSC, Canada
| | - Georg Hoffmann
- Neuropaediatrics and Paediatric Metabolic Medicine, University Hospital Heidelberg, Germany
| | | | - Dorothea Haas
- Neuropaediatrics and Paediatric Metabolic Medicine, University Hospital Heidelberg, Germany
| | - Ertan Mayatepek
- Department of General Paediatrics, Neonatology and Paediatric Cardiology, University Children's Hospital, Heinrich Heine University, Dusseldorf, Germany
| | - Andreas Schulze
- Clinical and Metabolic Genetics, HSC, Canada.,Department of Paediatrics, University of Toronto, Canada.,Department of Biochemistry, University of Toronto, Canada
| | - Elise Heon
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada.,Department of Ophthalmology and Vision Sciences, HSC and University of Toronto, Canada
| | - Ajoy Vincent
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada.,Department of Ophthalmology and Vision Sciences, HSC and University of Toronto, Canada
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Twists and turns of the genetic story of mevalonate kinase-associated diseases: A review. Genes Dis 2022; 9:1000-1007. [PMID: 35685471 PMCID: PMC9170606 DOI: 10.1016/j.gendis.2021.05.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/19/2021] [Accepted: 05/12/2021] [Indexed: 11/26/2022] Open
Abstract
Mevalonate kinase (MK)-associated diseases encompass a broad spectrum of rare auto-inflammatory conditions, all resulting from pathogenic variants in the mevalonate kinase gene (MVK). Their clinical manifestations are highly variable, ranging from more or less serious systemic disorders, such as hereditary recurrent fevers, to purely localized pathologies such as porokeratosis. The oldest condition identified as linked to this gene is a metabolic disease called mevalonic aciduria, and the most recent is disseminated superficial actinic porokeratosis, a disease limited to the skin. The modes of inheritance of MK-associated diseases also diverge among the different subtypes: recessive for the systemic subtypes and dominant with a post-zygotic somatic genetic alteration for MVK-associated porokeratosis. This review quickly retraces the historical steps that led to the description of the various MK-associated disease phenotypes and to a better understanding of their pathophysiology, then summarizes and compares the different genetic mechanisms involved in this group of disorders, and finally discusses the diverse causes that could underlie this phenotypic heterogeneity.
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Boursier G, Rittore C, Milhavet F, Cuisset L, Touitou I. Mevalonate Kinase-Associated Diseases: Hunting for Phenotype-Genotype Correlation. J Clin Med 2021; 10:jcm10081552. [PMID: 33917151 PMCID: PMC8067830 DOI: 10.3390/jcm10081552] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 12/11/2022] Open
Abstract
Mevalonate kinase-associated diseases (MKAD) are caused by pathogenic mutations in the mevalonate kinase gene (MVK) and encompass several phenotypically different rare and hereditary autoinflammatory conditions. The most serious is a recessive systemic metabolic disease called mevalonic aciduria, and the most recently recognized is disseminated superficial actinic porokeratosis, a dominant disease limited to the skin. To evaluate a possible correlation between genotypes and (1) the different MKAD clinical subtypes or (2) the occurrence of severe manifestations, data were reviewed for all patients with MVK variants described in the literature (N = 346), as well as those referred to our center (N = 51). The genotypes including p.(Val377Ile) (homozygous or compound heterozygous) were more frequent in mild systemic forms but were also sometimes encountered with severe disease. We confirmed that amyloidosis was more prevalent in patients compound heterozygous for p.(Ile268Thr) and p.(Val377Ile) than in others and revealed new associations. Patients homozygous for p.(Leu264Phe), p.(Ala334Thr) or compound heterozygous for p.(His20Pro) and p.(Ala334Thr) had increased risk of severe neurological or ocular symptoms. All patients homozygous for p.(Leu264Phe) had a cataract. The variants associated with porokeratosis were relatively specific and more frequently caused a frameshift than in patients with other clinical forms (26% vs. 6%). We provide practical recommendations focusing on phenotype-genotype correlation in MKAD that could be helpful for prophylactic management.
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Affiliation(s)
- Guilaine Boursier
- Department of Medical Genetics, Rare Diseases and Personalized Medicine, Rare and Autoinflammatory Diseases Unit, CHU, 34295 Montpellier, France; (G.B.); (C.R.); (F.M.)
| | - Cécile Rittore
- Department of Medical Genetics, Rare Diseases and Personalized Medicine, Rare and Autoinflammatory Diseases Unit, CHU, 34295 Montpellier, France; (G.B.); (C.R.); (F.M.)
| | - Florian Milhavet
- Department of Medical Genetics, Rare Diseases and Personalized Medicine, Rare and Autoinflammatory Diseases Unit, CHU, 34295 Montpellier, France; (G.B.); (C.R.); (F.M.)
- IRMB, University of Montpellier, INSERM, 34295 Montpellier, France
| | - Laurence Cuisset
- Genetic and Molecular Biology Laboratory, Cochin Hospital, 75014 Paris, France;
| | - Isabelle Touitou
- Department of Medical Genetics, Rare Diseases and Personalized Medicine, Rare and Autoinflammatory Diseases Unit, CHU, 34295 Montpellier, France; (G.B.); (C.R.); (F.M.)
- IRMB, University of Montpellier, INSERM, 34295 Montpellier, France
- Correspondence:
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Davison JE. Eye involvement in inherited metabolic disorders. Ther Adv Ophthalmol 2020; 12:2515841420979109. [PMID: 33447730 PMCID: PMC7780305 DOI: 10.1177/2515841420979109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 11/12/2020] [Indexed: 12/22/2022] Open
Abstract
Inherited metabolic disorders are a large group of rare disorders affecting normal biochemical pathways. Many metabolic disorders can present with symptoms affecting the eye, and eye disorders can evolve later in the natural history of an already diagnosed metabolic disorder. The ophthalmic involvement can be very varied affecting any part of the eye, including abnormalities of cornea, lens dislocation and cataracts, retina and the distal optic pathway, and extraocular muscles. Awareness of inherited metabolic disorders is important to facilitate early diagnosis and in some cases instigate early treatment if a patient presents with eye involvement suggestive of a metabolic disorder. Ophthalmological interventions are also an important component of the multisystem holistic approach to treating patients with metabolic disorders.
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Affiliation(s)
- James E. Davison
- Metabolic Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, NIHR GOSH Biomedical Research Centre (BRC), London WC1N 3JH, UK
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Raguz M, Kumar SN, Zareba M, Ilic N, Mainali L, Subczynski WK. Confocal Microscopy Confirmed that in Phosphatidylcholine Giant Unilamellar Vesicles with very High Cholesterol Content Pure Cholesterol Bilayer Domains Form. Cell Biochem Biophys 2019; 77:309-317. [PMID: 31625023 DOI: 10.1007/s12013-019-00889-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 09/28/2019] [Indexed: 12/14/2022]
Abstract
The cholesterol (Chol) content in the fiber cell plasma membranes of the eye lens is extremely high, exceeding the solubility threshold in the lenses of old humans. This high Chol content forms pure Chol bilayer domains (CBDs) and Chol crystals in model membranes and membranes formed from the total lipid extracts from human lenses. CBDs have been detected using electron paramagnetic resonance (EPR) spin-labeling approaches. Here, we confirm the presence of CBDs in giant unilamellar vesicles prepared using the electroformation method from Chol/1-palmitoyl-2-oleoylphosphocholine and Chol/distearoylphosphatidylcholine mixtures. Confocal microscopy experiments using phospholipid (PL) analog (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine-5,5'-disulfonic acid) and cholesterol analog fluorescent probes (23-(dipyrrometheneboron difluoride)-24-norcholesterol) were performed, allowing us to make three major conclusions: (1) In all membranes with a Chol/PL mixing ratio (expressed as a molar ratio) >2, pure CBDs were formed within the bulk PL bilayer saturated with Chol. (2) CBDs were present as the pure Chol bilayer and not as separate patches of Chol monolayers in each leaflet of the PL bilayer. (3) CBDs, presented as single large domains, were always located at the top of giant unilamellar vesicles, independent of the change in sample orientation (right-side-up/upside-down). Results obtained with confocal microscopy and fluorescent Chol and PL analogs, combined with those obtained using EPR and spin-labeled Chol and PL analogs, contribute to the understanding of the organization of lipids in the fiber cell plasma membranes of the human eye lens.
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Affiliation(s)
- Marija Raguz
- Department of Medical Physics and Biophysics, School of Medicine, University of Split, Split, Croatia. .,Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Suresh N Kumar
- Department of Pathology, CRI Imaging Core, Translational and Biomedical Research Center, Medical College of Wisconsin, Wauwatosa, WI, USA
| | - Mariusz Zareba
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Ophthalmology, Medical College of Wisconsin Eye Institute, Milwaukee, WI, USA
| | - Nada Ilic
- Department of Physics, Faculty of Science, University of Split, Split, Croatia
| | - Laxman Mainali
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Physics, Boise State University, 1910 University Drive, Boise, Idaho, 83725, USA
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Why Is Very High Cholesterol Content Beneficial for the Eye Lens but Negative for Other Organs? Nutrients 2019; 11:nu11051083. [PMID: 31096723 PMCID: PMC6566707 DOI: 10.3390/nu11051083] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/08/2019] [Accepted: 05/09/2019] [Indexed: 12/13/2022] Open
Abstract
The plasma membranes of the human lens fiber cell are overloaded with cholesterol that not only saturates the phospholipid bilayer of these membranes but also leads to the formation of pure cholesterol bilayer domains. Cholesterol level increases with age, and for older persons, it exceeds the cholesterol solubility threshold, leading to the formation of cholesterol crystals. All these changes occur in the normal lens without too much compromise to lens transparency. If the cholesterol content in the cell membranes of other organs increases to extent where cholesterol crystals forma, a pathological condition begins. In arterial cells, minute cholesterol crystals activate inflammasomes, induce inflammation, and cause atherosclerosis development. In this review, we will indicate possible factors that distinguish between beneficial and negative cholesterol action, limiting cholesterol actions to those performed through cholesterol in cell membranes and by cholesterol crystals.
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Kellner U, Stöhr H, Weinitz S, Farmand G, Weber BHF. Mevalonate kinase deficiency associated with ataxia and retinitis pigmentosa in two brothers with MVK gene mutations. Ophthalmic Genet 2017; 38:340-344. [PMID: 28095071 DOI: 10.1080/13816810.2016.1227459] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE To report the clinical and molecular genetic findings in two brothers with retinitis pigmentosa (RP) and mevalonate kinase deficiency (MKD). METHODS The brothers were examined clinically and with fundus autofluorescence, near-infrared autofluorescence, and spectral domain optical coherence tomography. Targeted resequencing was done with a custom designed gene panel containing 78 genes associated with RP. Mutations were confirmed by direct Sanger sequencing. RESULTS Both brothers, aged 46 and 47 years, were found to carry compound heterozygous mutations in the MVK gene (c.59A>C, c.1000G>A) encoding mevalonate kinase. They presented with severe ataxia, pseudophakia due to early onset cataract, and progressed retinitis pigmentosa. In one brother with cystoid macular edema, treatment with dorzolamide was beneficial. Serum IgD levels were markedly increased in both brothers and mevalonic acid blood and urine levels were markedly increased in the one brother who could be examined. The disease severity differed between the brothers-one had more severe ataxia and less severe visual deficiency compared to the other. CONCLUSION MKD can be associated with RP and early onset cataract. Most MKD patients developing RP carry the (p.Ala334Thr) mutation. Macular edema can be treated using local dorzolamide.
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Affiliation(s)
- Ulrich Kellner
- a Zentrum für Seltene Netzhauterkrankungen, AugenZentrum Siegburg , MVZ ADTC Siegburg GmbH , Siegburg , Germany.,b RetinaScience , Bonn , Germany
| | - Heidi Stöhr
- c Institut für Humangenetik , Universität Regensburg , Regensburg , Germany
| | - Silke Weinitz
- a Zentrum für Seltene Netzhauterkrankungen, AugenZentrum Siegburg , MVZ ADTC Siegburg GmbH , Siegburg , Germany.,b RetinaScience , Bonn , Germany
| | - Ghazaleh Farmand
- a Zentrum für Seltene Netzhauterkrankungen, AugenZentrum Siegburg , MVZ ADTC Siegburg GmbH , Siegburg , Germany
| | - Bernhard H F Weber
- c Institut für Humangenetik , Universität Regensburg , Regensburg , Germany
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