1
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Long D, Chan M, Han M, Kamdar Z, Ma RK, Tsai PY, Francisco AB, Barrow J, Shackelford DB, Yarchoan M, McBride MJ, Orre LM, Vacanti NM, Gujral TS, Sethupathy P. Proteo-metabolomics and patient tumor slice experiments point to amino acid centrality for rewired mitochondria in fibrolamellar carcinoma. Cell Rep Med 2024; 5:101699. [PMID: 39208801 DOI: 10.1016/j.xcrm.2024.101699] [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: 02/26/2024] [Revised: 06/12/2024] [Accepted: 08/03/2024] [Indexed: 09/04/2024]
Abstract
Fibrolamellar carcinoma (FLC) is a rare, lethal, early-onset liver cancer with a critical need for new therapeutics. The primary driver in FLC is the fusion oncoprotein, DNAJ-PKAc, which remains challenging to target therapeutically. It is critical, therefore, to expand understanding of the FLC molecular landscape to identify druggable pathways/targets. Here, we perform the most comprehensive integrative proteo-metabolomic analysis of FLC. We also conduct nutrient manipulation, respirometry analyses, as well as key loss-of-function assays in FLC tumor tissue slices from patients. We propose a model of cellular energetics in FLC pointing to proline anabolism being mediated by ornithine aminotransferase hyperactivity and ornithine transcarbamylase hypoactivity with serine and glutamine catabolism fueling the process. We highlight FLC's potential dependency on voltage-dependent anion channel (VDAC), a mitochondrial gatekeeper for anions including pyruvate. The metabolic rewiring in FLC that we propose in our model, with an emphasis on mitochondria, can be exploited for therapeutic vulnerabilities.
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Affiliation(s)
- Donald Long
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
| | - Marina Chan
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Mingqi Han
- Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA, USA
| | - Zeal Kamdar
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Bloomberg-Kimmel Institute for Cancer Immunotherapy, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rosanna K Ma
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Pei-Yin Tsai
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Adam B Francisco
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Joeva Barrow
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | | | - Mark Yarchoan
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Bloomberg-Kimmel Institute for Cancer Immunotherapy, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Matthew J McBride
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ, USA
| | - Lukas M Orre
- Department of Oncology and Pathology, Karolinska Institute, SciLifeLab, Solna, Sweden
| | | | - Taranjit S Gujral
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Praveen Sethupathy
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
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2
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Pampalone G, Chiasserini D, Pierigè F, Camaioni E, Orvietani PL, Bregalda A, Menotta M, Bellezza I, Rossi L, Cellini B, Magnani M. Biochemical Studies on Human Ornithine Aminotransferase Support a Cell-Based Enzyme Replacement Therapy in the Gyrate Atrophy of the Choroid and Retina. Int J Mol Sci 2024; 25:7931. [PMID: 39063173 PMCID: PMC11277095 DOI: 10.3390/ijms25147931] [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: 05/24/2024] [Revised: 07/12/2024] [Accepted: 07/17/2024] [Indexed: 07/28/2024] Open
Abstract
The gyrate atrophy of the choroid and retina (GACR) is a rare genetic disease for which no definitive cure is available. GACR is due to the deficit of ornithine aminotransferase (hOAT), a pyridoxal 5'-phosphate-dependent enzyme responsible for ornithine catabolism. The hallmark of the disease is plasmatic ornithine accumulation, which damages retinal epithelium leading to progressive vision loss and blindness within the fifth decade. Here, we characterized the biochemical properties of tetrameric and dimeric hOAT and evaluated hOAT loaded in red blood cells (RBCs) as a possible enzyme replacement therapy (ERT) for GACR. Our results show that (i) hOAT has a relatively wide specificity for amino acceptors, with pyruvate being the most suitable candidate for ornithine catabolism within RBCs; (ii) both the tetrameric and dimeric enzyme can be loaded in RBC retaining their activity; and (iii) hOAT displays reduced stability in plasma, but is partly protected from inactivation upon incubation in a mixture mimicking the intracellular erythrocyte environment. Preliminary ex vivo experiments indicate that hOAT-loaded RBCs are able to metabolize extracellular ornithine at a concentration mimicking that found in patients, both in buffer and, although with lower efficiency, in plasma. Overall, our data provide a proof of concept that an RBC-mediated ERT is feasible and can be exploited as a new therapeutic approach in GACR.
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Affiliation(s)
- Gioena Pampalone
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, 06132 Perugia, Italy; (G.P.); (D.C.); (P.L.O.); (I.B.)
| | - Davide Chiasserini
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, 06132 Perugia, Italy; (G.P.); (D.C.); (P.L.O.); (I.B.)
| | - Francesca Pierigè
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (F.P.); (A.B.); (M.M.); (M.M.)
| | - Emidio Camaioni
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06122 Perugia, Italy;
| | - Pier Luigi Orvietani
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, 06132 Perugia, Italy; (G.P.); (D.C.); (P.L.O.); (I.B.)
| | - Alessandro Bregalda
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (F.P.); (A.B.); (M.M.); (M.M.)
| | - Michele Menotta
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (F.P.); (A.B.); (M.M.); (M.M.)
| | - Ilaria Bellezza
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, 06132 Perugia, Italy; (G.P.); (D.C.); (P.L.O.); (I.B.)
| | - Luigia Rossi
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (F.P.); (A.B.); (M.M.); (M.M.)
| | - Barbara Cellini
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, 06132 Perugia, Italy; (G.P.); (D.C.); (P.L.O.); (I.B.)
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (F.P.); (A.B.); (M.M.); (M.M.)
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3
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Seah I, Goh D, Banerjee A, Su X. Modeling inherited retinal diseases using human induced pluripotent stem cell derived photoreceptor cells and retinal pigment epithelial cells. Front Med (Lausanne) 2024; 11:1328474. [PMID: 39011458 PMCID: PMC11246861 DOI: 10.3389/fmed.2024.1328474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 06/18/2024] [Indexed: 07/17/2024] Open
Abstract
Since the discovery of induced pluripotent stem cell (iPSC) technology, there have been many attempts to create cellular models of inherited retinal diseases (IRDs) for investigation of pathogenic processes to facilitate target discovery and validation activities. Consistency remains key in determining the utility of these findings. Despite the importance of consistency, quality control metrics are still not widely used. In this review, a toolkit for harnessing iPSC technology to generate photoreceptor, retinal pigment epithelial cell, and organoid disease models is provided. Considerations while developing iPSC-derived IRD models such as iPSC origin, reprogramming methods, quality control metrics, control strategies, and differentiation protocols are discussed. Various iPSC IRD models are dissected and the scientific hurdles of iPSC-based disease modeling are discussed to provide an overview of current methods and future directions in this field.
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Affiliation(s)
- Ivan Seah
- Translational Retinal Research Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
| | - Debbie Goh
- Department of Ophthalmology, National University Hospital (NUH), Singapore, Singapore
| | - Animesh Banerjee
- Translational Retinal Research Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Xinyi Su
- Translational Retinal Research Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Ophthalmology, National University Hospital (NUH), Singapore, Singapore
- Singapore Eye Research Institute (SERI), Singapore, Singapore
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4
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Boffa I, Brunetti-Pierri N. Vision on gyrate atrophy: why treat the liver? EMBO Mol Med 2024; 16:8-9. [PMID: 38177527 PMCID: PMC10883274 DOI: 10.1038/s44321-023-00002-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 11/09/2023] [Indexed: 01/06/2024] Open
Affiliation(s)
- Iolanda Boffa
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Nicola Brunetti-Pierri
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy.
- Department of Translational Medicine, "Federico II" University, Naples, Italy.
- Scuola Superiore Meridionale (SSM, School of Advanced Studies), Genomics and Experimental Medicine Program, University of Naples Federico II, Naples, Italy.
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Bergen AA, Buijs MJ, Ten Asbroek AL, Balfoort BM, Boon CJ, Brands MM, Wanders RJ, van Karnebeek CD, Houtkooper RH. Vision on gyrate atrophy: why treat the eye? EMBO Mol Med 2024; 16:4-7. [PMID: 38177529 PMCID: PMC10883273 DOI: 10.1038/s44321-023-00001-1] [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: 07/17/2023] [Revised: 09/29/2023] [Accepted: 10/09/2023] [Indexed: 01/06/2024] Open
Abstract
In the April issue of this Journal, Boffa and coworkers put forward a new therapeutic approach for Gyrate Atrophy of the Choroid and Retina (GACR; OMIM 258870) (Boffa et al, 2023). The authors propose to apply gene therapy to the liver for GACR, a metabolic disease primarily affecting eyesight due to retinal degeneration. Their vision is enthusiastically supported by a News and Views comment in the same issue (Seker Yilmaz and Gissen, 2023). However, based on disease pathology, patient's needs, ethical considerations, therapeutic developmental time lines, and current state of the art of gene therapy for liver and eye, we have a different view on this issue: We argue below that local treatment of the eye is the preferred option for GACR.
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Affiliation(s)
- Arthur A Bergen
- Department of Human Genetics, Section Ophthalmogenetics, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, the Netherlands
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, the Netherlands
- Emma Center for Personalized Medicine, Amsterdam UMC, Amsterdam, the Netherlands
| | - Mark Jn Buijs
- Department of Human Genetics, Section Ophthalmogenetics, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, the Netherlands
| | - Anneloor Lma Ten Asbroek
- Department of Human Genetics, Section Ophthalmogenetics, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, the Netherlands
| | - Berith M Balfoort
- Department of Paediatrics, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, the Netherlands
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, the Netherlands
| | - Camiel Jf Boon
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, the Netherlands
- Department of Ophthalmology, Leiden UMC, Leiden, the Netherlands
| | - Marion M Brands
- Emma Center for Personalized Medicine, Amsterdam UMC, Amsterdam, the Netherlands
- Department of Paediatrics, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, the Netherlands
- United for Metabolic Diseases, Amsterdam, The Netherlands
| | - Ronald Ja Wanders
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, the Netherlands
- United for Metabolic Diseases, Amsterdam, The Netherlands
| | - Clara Dm van Karnebeek
- Emma Center for Personalized Medicine, Amsterdam UMC, Amsterdam, the Netherlands
- Department of Paediatrics, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, the Netherlands
- United for Metabolic Diseases, Amsterdam, The Netherlands
| | - Riekelt H Houtkooper
- Emma Center for Personalized Medicine, Amsterdam UMC, Amsterdam, the Netherlands.
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, the Netherlands.
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Pauleikhoff L, Weisschuh N, Lentzsch A, Spital G, Krohne TU, Agostini H, Lange CAK. Clinical characteristics of gyrate atrophy compared with a gyrate atrophy-like retinal phenotype. Eur J Ophthalmol 2024; 34:79-88. [PMID: 37218157 DOI: 10.1177/11206721231178147] [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: 05/24/2023]
Abstract
INTRODUCTION Gyrate atrophy (GA) is a rare retinal dystrophy due to biallelic pathogenic variants in the ornithine aminotransferase (OAT) gene, causing a 10-fold increase in plasma ornithine levels. It is characterized by circular patches of chorioretinal atrophy. However, a GA-like retinal phenotype (GALRP) without elevated ornithine levels has also been reported. The aim of this study is to compare the clinical characteristics of GA and GALRP and to identify possible discriminators. METHODS A multicenter, retrospective chart review was performed at three German referral centres on patient records between 01/01/2009 and 31/12/2021. Records were screened for patients affected by GA or GALRP. Only patients with examination results for plasma ornithine levels and / or genetic testing of the OAT gene were included. Further clinical data was gathered where available. RESULTS Ten patients (5 female) were included in the analysis. Three suffered from GA, while seven had a GALRP. Mean age (± SD) at onset of symptoms was 12.3 (± 3.5) years for GA compared with 46.7 (± 14.0) years for GALRP patients (p = 0.002). Mean degree of myopia was higher in GA (-8.0 dpt. ± 3.6) compared to GALRP patients (-3.8 dpt. ± 4.8, p = 0.04). Interestingly, all GA patients showed macular oedema, while only one GALRP patient did. Only one patient with GALRP had a positive family history, while two were immunosuppressed. DISCUSSION Age of onset, refraction and presence of macular cystoid cavities appear to be discriminators between GA and GALRP. GALRP may encompass both genetic and non-genetic subtypes.
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Affiliation(s)
- L Pauleikhoff
- Eye Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Ophthalmology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - N Weisschuh
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - A Lentzsch
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - G Spital
- St. Franziskus Eye Center, Münster, Germany
| | - T U Krohne
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - H Agostini
- Eye Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Zhu S, Xu R, Engel AL, Wang Y, McNeel R, Hurley JB, Chao JR, Du J. Proline provides a nitrogen source in the retinal pigment epithelium to synthesize and export amino acids for the neural retina. J Biol Chem 2023; 299:105275. [PMID: 37741457 PMCID: PMC10616405 DOI: 10.1016/j.jbc.2023.105275] [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: 04/19/2023] [Revised: 09/07/2023] [Accepted: 09/11/2023] [Indexed: 09/25/2023] Open
Abstract
It is known that metabolic defects in the retinal pigment epithelium (RPE) can cause degeneration of its neighboring photoreceptors in the retina, leading to retinal degenerative diseases such as age-related macular degeneration. However, how RPE metabolism supports the health of the neural retina remains unclear. The retina requires exogenous nitrogen sources for protein synthesis, neurotransmission, and energy metabolism. Using 15N tracing coupled with mass spectrometry, we found human RPE can utilize the nitrogen in proline to produce and export 13 amino acids, including glutamate, aspartate, glutamine, alanine, and serine. Similarly, we found this proline nitrogen utilization in the mouse RPE/choroid but not in the neural retina of explant cultures. Coculture of human RPE with the retina showed that the retina can take up the amino acids, especially glutamate, aspartate, and glutamine, generated from proline nitrogen in the RPE. Intravenous delivery of 15N proline in vivo demonstrated 15N-derived amino acids appear earlier in the RPE before the retina. We also found proline dehydrogenase, the key enzyme in proline catabolism is highly enriched in the RPE but not the retina. The deletion of proline dehydrogenase blocks proline nitrogen utilization in RPE and the import of proline nitrogen-derived amino acids in the retina. Our findings highlight the importance of RPE metabolism in supporting nitrogen sources for the retina, providing insight into understanding the mechanisms of the retinal metabolic ecosystem and RPE-initiated retinal degenerative diseases.
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Affiliation(s)
- Siyan Zhu
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA; Department of Pharmaceutical and Pharmacological Sciences, West Virginia University, Morgantown, West Virginia, USA
| | - Rong Xu
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Abbi L Engel
- Department of Ophthalmology, University of Washington, Seattle, Washington, USA
| | - Yekai Wang
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Rachel McNeel
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - James B Hurley
- Department of Ophthalmology, University of Washington, Seattle, Washington, USA; Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Jennifer R Chao
- Department of Ophthalmology, University of Washington, Seattle, Washington, USA.
| | - Jianhai Du
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA.
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Palmer E, Stepien KM, Campbell C, Barton S, Iosifidis C, Ghosh A, Broomfield A, Woodall A, Wilcox G, Sergouniotis PI, Black GC. Clinical, biochemical and molecular analysis in a cohort of individuals with gyrate atrophy. Orphanet J Rare Dis 2023; 18:265. [PMID: 37667371 PMCID: PMC10476330 DOI: 10.1186/s13023-023-02840-0] [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: 01/31/2023] [Accepted: 07/21/2023] [Indexed: 09/06/2023] Open
Abstract
BACKGROUND Gyrate atrophy of the choroid and retina is a rare autosomal recessive metabolic disorder caused by biallelic variants in the OAT gene, encoding the enzyme ornithine δ-aminotransferase. Impaired enzymatic activity leads to systemic hyperornithinaemia, which in turn underlies progressive chorioretinal degeneration. In this study, we describe the clinical and molecular findings in a cohort of individuals with gyrate atrophy. METHODS Study participants were recruited through a tertiary UK clinical ophthalmic genetic service. All cases had a biochemical and molecular diagnosis of gyrate atrophy. Retrospective phenotypic and biochemical data were collected using electronic healthcare records. RESULTS 18 affected individuals from 12 families (8 male, 10 female) met the study inclusion criteria. The median age at diagnosis was 8 years (range 10 months - 33 years) and all cases had hyperornithinaemia (median: 800 micromoles/L; range: 458-1244 micromoles/L). Common features at presentation included high myopia (10/18) and nyctalopia (5/18). Ophthalmic findings were present in all study participants who were above the age of 6 years. One third of patients had co-existing macular oedema and two thirds developed pre-senile cataracts. Compliance with dietary modifications was suboptimal in most cases. A subset of participants had extraocular features including a trend towards reduced fat-free mass and developmental delay. CONCLUSIONS Our findings highlight the importance of multidisciplinary care in families with gyrate atrophy. Secondary ophthalmic complications such as macular oedema and cataract formation are common. Management of affected individuals remains challenging due to the highly restrictive nature of the recommended diet and the limited evidence-base for current strategies.
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Affiliation(s)
- Eleanor Palmer
- Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Karolina M Stepien
- Adult Inherited Metabolic Disorders, Salford Royal NHS Foundation Trust, Salford, Greater Manchester, UK
- Division of Diabetes, Endocrinology and Gastroenterology, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Christopher Campbell
- Manchester Centre for Genomic Medicine, Saint Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Stephanie Barton
- Manchester Centre for Genomic Medicine, Saint Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Christos Iosifidis
- Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Arunabha Ghosh
- Willink Biochemical Genetics, Royal Manchester Children's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Alexander Broomfield
- Willink Biochemical Genetics, Royal Manchester Children's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Alison Woodall
- Adult Inherited Metabolic Disorders, Salford Royal NHS Foundation Trust, Salford, Greater Manchester, UK
- Division of Diabetes, Endocrinology and Gastroenterology, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Gisela Wilcox
- Adult Inherited Metabolic Disorders, Salford Royal NHS Foundation Trust, Salford, Greater Manchester, UK
- Division of Diabetes, Endocrinology and Gastroenterology, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Panagiotis I Sergouniotis
- Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester, UK.
- Manchester Centre for Genomic Medicine, Saint Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK.
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
| | - Graeme C Black
- Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester, UK.
- Manchester Centre for Genomic Medicine, Saint Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK.
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
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Zhu S, Xu R, Engel AL, Wang Y, McNeel R, Hurley JB, Chao JR, Du J. Proline provides a nitrogen source in the retinal pigment epithelium to synthesize and export amino acids for the neural retina. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.18.537355. [PMID: 37131780 PMCID: PMC10153141 DOI: 10.1101/2023.04.18.537355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
It is known that metabolic defects in the retinal pigment epithelium (RPE) can cause degeneration of its neighboring photoreceptors in the retina, leading to retinal degenerative diseases such as age-related macular degeneration. However, how RPE metabolism supports the health of the neural retina remains unclear. The retina requires exogenous nitrogen sources for protein synthesis, neurotransmission, and energy metabolism. Using 15N tracing coupled with mass spectrometry, we found human RPE can utilize the nitrogen in proline to produce and export 13 amino acids, including glutamate, aspartate, glutamine, alanine and serine. Similarly, we found this proline nitrogen utilization in the mouse RPE/choroid but not in the neural retina of explant cultures. Co-culture of human RPE with the retina showed that the retina can take up the amino acids, especially glutamate, aspartate and glutamine, generated from proline nitrogen in the RPE. Intravenous delivery of 15N proline in vivo demonstrated 15N-derived amino acids appear earlier in the RPE before the retina. We also found proline dehydrogenase (PRODH), the key enzyme in proline catabolism is highly enriched in the RPE but not the retina. The deletion of PRODH blocks proline nitrogen utilization in RPE and the import of proline nitrogen-derived amino acids in the retina. Our findings highlight the importance of RPE metabolism in supporting nitrogen sources for the retina, providing insight into understanding the mechanisms of the retinal metabolic ecosystem and RPE-initiated retinal degenerative diseases.
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Affiliation(s)
- Siyan Zhu
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV 26506
- Department of Pharmaceutical and Pharmacological Sciences, West Virginia University, Morgantown, WV 26506
| | - Rong Xu
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV 26506
| | - Abbi L. Engel
- Department of Ophthalmology, University of Washington, Seattle, WA 98109
| | - Yekai Wang
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV 26506
| | - Rachel McNeel
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV 26506
| | - James B. Hurley
- Department of Ophthalmology, University of Washington, Seattle, WA 98109
- Department of Biochemistry, University of Washington, Seattle, WA 98109
| | - Jennifer R. Chao
- Department of Ophthalmology, University of Washington, Seattle, WA 98109
| | - Jianhai Du
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV 26506
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10
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Boffa I, Polishchuk E, De Stefano L, Dell'Aquila F, Nusco E, Marrocco E, Audano M, Pedretti S, Caterino M, Bellezza I, Ruoppolo M, Mitro N, Cellini B, Auricchio A, Brunetti‐Pierri N. Liver-directed gene therapy for ornithine aminotransferase deficiency. EMBO Mol Med 2023; 15:e17033. [PMID: 36647689 PMCID: PMC10086579 DOI: 10.15252/emmm.202217033] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/16/2022] [Accepted: 12/19/2022] [Indexed: 01/18/2023] Open
Abstract
Gyrate atrophy of choroid and retina (GACR) is a chorioretinal degeneration caused by pathogenic variants in the gene encoding ornithine aminotransferase (OAT), an enzyme mainly expressed in liver. Affected patients have increased ornithine concentrations in blood and other body fluids and develop progressive constriction of vision fields leading to blindness. Current therapies are unsatisfactory and better treatments are highly needed. In two mouse models of OAT deficiency that recapitulates biochemical and retinal changes of GACR, we investigated the efficacy of an intravenously injected serotype 8 adeno-associated (AAV8) vector expressing OAT under the control of a hepatocyte-specific promoter. Following injections, OAT-deficient mice showed reductions of ornithine concentrations in blood and eye cups compared with control mice injected with a vector expressing green fluorescent protein. AAV-injected mice showed improved electroretinogram response and partial restoration of retinal structure up to one-year post-injection. In summary, hepatic OAT expression by AAV8 vector was effective at correction of hyperornithinemia and improved function and structure of the retina. In conclusion, this study provides proof-of-concept of efficacy of liver-directed AAV-mediated gene therapy of GACR.
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Affiliation(s)
- Iolanda Boffa
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | - Elena Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | - Lucia De Stefano
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | | | - Edoardo Nusco
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | - Elena Marrocco
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | - Matteo Audano
- Department of Pharmacology and Biomolecular SciencesUniversity of MilanMilanItaly
| | - Silvia Pedretti
- Department of Pharmacology and Biomolecular SciencesUniversity of MilanMilanItaly
| | - Marianna Caterino
- Department of Molecular Medicine and Medical BiotechnologyUniversity of Naples “Federico II”NaplesItaly
- CEINGE – Biotecnologie Avanzate s.c.a.r.l.NaplesItaly
| | - Ilaria Bellezza
- Department of Experimental Medicine, Section of Physiology and BiochemistryUniversity of PerugiaPerugiaItaly
| | - Margherita Ruoppolo
- Department of Molecular Medicine and Medical BiotechnologyUniversity of Naples “Federico II”NaplesItaly
- CEINGE – Biotecnologie Avanzate s.c.a.r.l.NaplesItaly
| | - Nico Mitro
- Department of Pharmacology and Biomolecular SciencesUniversity of MilanMilanItaly
- Department of Experimental Oncology, IEOEuropean Institute of Oncology IRCCSMilanItaly
| | - Barbara Cellini
- Department of Experimental Medicine, Section of Physiology and BiochemistryUniversity of PerugiaPerugiaItaly
| | - Alberto Auricchio
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Department of Advanced Biomedical Sciences“Federico II” UniversityNaplesItaly
| | - Nicola Brunetti‐Pierri
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Department of Translational Medicine“Federico II” UniversityNaplesItaly
- Scuola Superiore Meridionale (SSM, School of Advanced Studies), Genomics and Experimental Medicine ProgramUniversity of Naples Federico IINaplesItaly
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11
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Douda L, Hyšpler R, Mžik M, Vokurková D, Drahošová M, Řeháček V, Čermáková E, Douda T, Cyrany J, Fejfar T, Jirkovský V, Kopáčová M, Kupková B, Vašátko T, Tachecí I, Bureš J. Serum Citrulline and Ornithine: Potential Markers of Coeliac Disease Activity. ACTA MEDICA (HRADEC KRALOVE) 2023; 65:75-82. [PMID: 36735884 DOI: 10.14712/18059694.2022.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
INTRODUCTION To date, there is not generally accepted and universal indicator of activity, and functional integrity of the small intestine in patients with coeliac disease. The aim of our study was to investigate whether serum concentrations of the non-essential amino acids citrulline and ornithine might have this function. METHODS We examined serum citrulline and ornithine concentrations in a subgroup of patients with proven coeliac disease and healthy controls (blood donors). RESULTS A total of 94 patients with coeliac disease (29 men, mean age 53 ± 18 years; 65 women, mean age 44 ± 14 years) and 35 healthy controls (blood donors) in whom coeliac disease was serologically excluded (10 men, mean age 51 ± 14 years; 25 women, mean age 46 ± 12 years) were included in the study. Significantly lower concentrations of serum ornithine were found in patients with coeliac disease (mean 65 ± 3 μmol/L; median 63 μmol/L, IQR 34 μmol/L, p < 0.001). No statistically nor clinically significant differences were found in the citrulline concentrations between the study and control group. CONCLUSIONS Serum ornithine (but not citrulline) may be useful for assessing the functional status of the small intestine in uncomplicated coeliac disease. Further studies involving more detailed analysis of dietary and metabolic changes in patients will be needed to reach definitive conclusions.
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Affiliation(s)
- Ladislav Douda
- 2nd Department of Internal Medicine - Gastroenterology, Charles University, Faculty of Medicine in Hradec Králové and University Hospital Hradec Králové, Czech Republic
| | - Radomír Hyšpler
- Institute of Clinical Biochemistry and Diagnostics, Charles University, Faculty of Medicine in Hradec Králové and University Hospital Hradec Králové, Czech Republic
| | - Martin Mžik
- Institute of Clinical Biochemistry and Diagnostics, Charles University, Faculty of Medicine in Hradec Králové and University Hospital Hradec Králové, Czech Republic
| | - Doris Vokurková
- Department of Clinical Immunology and Allergology, Charles University, Faculty of Medicine in Hradec Králové and University Hospital Hradec Králové, Czech Republic
| | - Marcela Drahošová
- Department of Clinical Immunology and Allergology, Charles University, Faculty of Medicine in Hradec Králové and University Hospital Hradec Králové, Czech Republic
| | - Vít Řeháček
- Transfusion Department, University Hospital Hradec Králové, Czech Republic
| | - Eva Čermáková
- Department of Medical Biophysic, Charles University, Faculty of Medicine in Hradec Králové, Czech Republic
| | - Tomáš Douda
- 2nd Department of Internal Medicine - Gastroenterology, Charles University, Faculty of Medicine in Hradec Králové and University Hospital Hradec Králové, Czech Republic
| | - Jiří Cyrany
- 2nd Department of Internal Medicine - Gastroenterology, Charles University, Faculty of Medicine in Hradec Králové and University Hospital Hradec Králové, Czech Republic
| | - Tomáš Fejfar
- 2nd Department of Internal Medicine - Gastroenterology, Charles University, Faculty of Medicine in Hradec Králové and University Hospital Hradec Králové, Czech Republic
| | - Václav Jirkovský
- 2nd Department of Internal Medicine - Gastroenterology, Charles University, Faculty of Medicine in Hradec Králové and University Hospital Hradec Králové, Czech Republic
| | - Marcela Kopáčová
- 2nd Department of Internal Medicine - Gastroenterology, Charles University, Faculty of Medicine in Hradec Králové and University Hospital Hradec Králové, Czech Republic
| | - Blanka Kupková
- 2nd Department of Internal Medicine - Gastroenterology, Charles University, Faculty of Medicine in Hradec Králové and University Hospital Hradec Králové, Czech Republic
| | - Tomáš Vašátko
- 2nd Department of Internal Medicine - Gastroenterology, Charles University, Faculty of Medicine in Hradec Králové and University Hospital Hradec Králové, Czech Republic
| | - Ilja Tachecí
- 2nd Department of Internal Medicine - Gastroenterology, Charles University, Faculty of Medicine in Hradec Králové and University Hospital Hradec Králové, Czech Republic.
| | - Jan Bureš
- Biomedical Research Centre, University Hospital Hradec Králové, Hradec Králové, Czech Republic
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12
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Mele S, Martelli F, Lin J, Kanca O, Christodoulou J, Bellen HJ, Piper MDW, Johnson TK. Drosophila as a diet discovery tool for treating amino acid disorders. Trends Endocrinol Metab 2023; 34:85-105. [PMID: 36567227 DOI: 10.1016/j.tem.2022.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022]
Abstract
Amino acid disorders (AADs) are a large group of rare inherited conditions that collectively impact one in 6500 live births, often resulting in rapid neurological decline and death during infancy. For several AADs, including phenylketonuria, dietary modification prevents physiological deterioration and ameliorates symptoms. Despite this remarkable potential for treatment success, dietary therapy for most AADs remains largely unexplored. Although animal models have provided novel insights into AAD mechanisms, few have been used for therapeutic diet discovery. Here, we find that of all the animal models, Drosophila is particularly well suited for nutrigenomic disease modelling, having amino acid pathways conserved with humans, exceptional genetic tractability, and the unique availability of a synthetic customisable diet.
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Affiliation(s)
- Sarah Mele
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Felipe Martelli
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Jiayi Lin
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Oguz Kanca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Duncan Neurological Research Institute of Texas Children's Hospital, Baylor College of Medicine, Houston, TX, USA
| | - John Christodoulou
- Murdoch Children's Research Institute, Parkville, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Duncan Neurological Research Institute of Texas Children's Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Matthew D W Piper
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.
| | - Travis K Johnson
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.
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13
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Liu Z, Sun D, Wang C. Evaluation of cell-cell interaction methods by integrating single-cell RNA sequencing data with spatial information. Genome Biol 2022; 23:218. [PMID: 36253792 PMCID: PMC9575221 DOI: 10.1186/s13059-022-02783-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 10/04/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Cell-cell interactions are important for information exchange between different cells, which are the fundamental basis of many biological processes. Recent advances in single-cell RNA sequencing (scRNA-seq) enable the characterization of cell-cell interactions using computational methods. However, it is hard to evaluate these methods since no ground truth is provided. Spatial transcriptomics (ST) data profiles the relative position of different cells. We propose that the spatial distance suggests the interaction tendency of different cell types, thus could be used for evaluating cell-cell interaction tools. RESULTS We benchmark 16 cell-cell interaction methods by integrating scRNA-seq with ST data. We characterize cell-cell interactions into short-range and long-range interactions using spatial distance distributions between ligands and receptors. Based on this classification, we define the distance enrichment score and apply an evaluation workflow to 16 cell-cell interaction tools using 15 simulated and 5 real scRNA-seq and ST datasets. We also compare the consistency of the results from single tools with the commonly identified interactions. Our results suggest that the interactions predicted by different tools are highly dynamic, and the statistical-based methods show overall better performance than network-based methods and ST-based methods. CONCLUSIONS Our study presents a comprehensive evaluation of cell-cell interaction tools for scRNA-seq. CellChat, CellPhoneDB, NicheNet, and ICELLNET show overall better performance than other tools in terms of consistency with spatial tendency and software scalability. We recommend using results from at least two methods to ensure the accuracy of identified interactions. We have packaged the benchmark workflow with detailed documentation at GitHub ( https://github.com/wanglabtongji/CCI ).
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Affiliation(s)
- Zhaoyang Liu
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Department of Orthopedics, Tongji Hospital, School of Life Science and Technology, Tongji University, Shanghai, 200092, China
- Frontier Science Center for Stem Cells, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China
| | - Dongqing Sun
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Department of Orthopedics, Tongji Hospital, School of Life Science and Technology, Tongji University, Shanghai, 200092, China
- Frontier Science Center for Stem Cells, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China
| | - Chenfei Wang
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Department of Orthopedics, Tongji Hospital, School of Life Science and Technology, Tongji University, Shanghai, 200092, China.
- Frontier Science Center for Stem Cells, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China.
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14
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Maldonado R, Jalil S, Keskinen T, Nieminen AI, Hyvönen ME, Lapatto R, Wartiovaara K. CRISPR correction of the Finnish ornithine delta-aminotransferase mutation restores metabolic homeostasis in iPSC from patients with gyrate atrophy. Mol Genet Metab Rep 2022; 31:100863. [PMID: 35782600 PMCID: PMC9248217 DOI: 10.1016/j.ymgmr.2022.100863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 03/18/2022] [Indexed: 11/26/2022] Open
Abstract
Hyperornithinemia with gyrate atrophy of the choroid and retina (HOGA) is a severe recessive inherited disease, causing muscular degeneration and retinochoroidal atrophy that progresses to blindness. HOGA arises from mutations in the ornithine aminotransferase (OAT) gene, and nearly one-third of the known patients worldwide are homozygous for the Finnish founder mutation OAT c.1205 T > C p.(Leu402Pro). We have corrected this loss-of-function OAT mutation in patient-derived induced pluripotent stem cells (iPSCs) using CRISPR/Cas9. The correction restored OAT expression in stem cells and normalized the elevated ornithine levels in cell lysates and cell media. These results show an efficient recovery of OAT function in iPSC, encouraging the possibility of autologous cell therapy for the HOGA disease.
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Affiliation(s)
- Rocio Maldonado
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Sami Jalil
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Timo Keskinen
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anni I. Nieminen
- Metabolomics Unit, Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland
| | - Mervi E. Hyvönen
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Risto Lapatto
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Kirmo Wartiovaara
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Clinical Genetics, Helsinki University Hospital, Helsinki, Finland
- Corresponding author at: Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
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15
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Nitta K, Mukai R, Akiyama H. Obscured interdigitation zone at the early stage of gyrate atrophy: A case report. Am J Ophthalmol Case Rep 2022; 25:101277. [PMID: 35112019 PMCID: PMC8790631 DOI: 10.1016/j.ajoc.2022.101277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/22/2021] [Accepted: 01/13/2022] [Indexed: 11/28/2022] Open
Abstract
Purpose To report an early stage of gyrate atrophy (GA) of the retina and choroid for which spectral-domain optical coherence tomography (SD-OCT) images revealed an obscured interdigitation zone (IZ). Observation A 13-year-old boy was referred to our department due to blurred vision in his left eye. Best corrected visual acuity was 20/20 and 20/25 in the right and left eye, respectively. Fundus examination revealed scalloped atrophic peripheral chorioretinal lesions in both eyes. Concentrations of plasma and urine ornithine were 1192 nmol/mL and 1930 μmol/g·cre, respectively. Consequently, he was diagnosed with GA. Although Goldmann perimetry found no abnormalities, electroretinogram (ERG) revealed loss of the rod responses and significant attenuation of the cone responses in both eyes. Detailed analysis of the posterior part of the fundus using multifocal electroretinogram showed poor responses, specifically in the nasal macular area of the left eye. SD-OCT showed an obscured IZ corresponding to the attenuated cone response determined by ERG. There was preservation of the retinal pigment epithelium, ellipsoid zone and external limiting membrane. Conclusions and Importance Obscured IZ during early stage GA was confirmed in a teenage patient with a chief complaint of blurred vision. OCT is useful in the detection of minute morphological changes that occur earlier in GA.
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16
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Ames BN. Musings in the twilight of my career. Free Radic Biol Med 2022; 178:219-225. [PMID: 34863877 DOI: 10.1016/j.freeradbiomed.2021.11.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/22/2021] [Accepted: 11/29/2021] [Indexed: 10/19/2022]
Abstract
I present a summary of my research during the last few decades of research which focused on understanding the biochemical basis for maintaining an optimum metabolism to support long-term health. I realized that adequate levels of ∼40 vitamins and minerals needed as cofactors in thousands of metabolic reactions were critical for maintaining a healthy metabolism, and thus for longevity and prevention of chronic disease. Inadequate dietary intake of vitamins and minerals accelerates the risk of aging-associated diseases, leading to insidious damage. The Triage Theory provides a mechanistic rationale for such damage: shortage of a nutrient triggers a built-in rationing mechanism that allocates the scarce nutrient to proteins needed for immediate survival (survival proteins), at the expense of those needed for long-term survival (longevity proteins). Many as-yet-unknown longevity vitamins and proteins likely remain to be discovered. The fiber and nutrient-rich CHORI-bar was developed to fill gaps in inadequate diets; it yielded broadscale metabolic improvements. The health-related damages resulting from vitamin D deficiency and the positive effects of vitamin D supplementation were connected to numerous health-related problems, including the higher level of deficiency in people of color residing at northern latitudes. In general, prevention of degenerative diseases of aging requires expertise in metabolism, nutrition, biochemistry and regulatory functions.
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Affiliation(s)
- Bruce N Ames
- Emeritus, Department of Molecular and Cell Biology, University of California, Berkeley, USA.
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17
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Abstract
Gyrate atrophy (GA) of the choroid and retina is a rare autosomal recessive genetic condition characterized by elevation of the plasma level of the amino acid ornithine due to deficiency of the enzyme ornithine ketoacid aminotransferase. Accumulation of ornithine occurs in various body tissues but leads primarily to characteristic ophthalmic manifestations including myopia, cataract, progressive chorioretinal atrophy, and macular changes. Patients usually present with night blindness that starts in the first decade of life followed by visual field constriction and eventually diminution of the central visual acuity and blindness. The condition has been reported worldwide and its differential diagnosis is broad and includes choroideremia and retinitis pigmentosa. Treatment currently depends on life-long dietary modifications including restriction of the amino acid arginine in diet. This article describes in detail the pathogenesis, clinical features, multimodal imaging findings, and treatment options for GA of the choroid and retina and its complications.
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Affiliation(s)
- Ayman G Elnahry
- Department of Ophthalmology, Faculty of Medicine, 63526Cairo University, Cairo, Egypt
| | - Gehad A Elnahry
- Department of Ophthalmology, Faculty of Medicine, 63526Cairo University, Cairo, Egypt
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18
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Kanninen T, Bryant E, Koerner C, Gonik B. First reported case of pregnancy in a patient with ornithine aminotransferase deficiency. Nutrition 2021; 93:111513. [PMID: 34768032 DOI: 10.1016/j.nut.2021.111513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 09/17/2021] [Accepted: 10/03/2021] [Indexed: 11/29/2022]
Abstract
Ornithine aminotransferase deficiency is a rare autosomalrecessive human inborn error of the metabolism resulting in hyperornithinemia and progressive chorioretinal degeneration (gyrate atrophy) with blindness. There are few reports in the literature and none, to our knowledge, that address this condition during pregnancy. We report on a novel case of ornithine aminotransferase deficiency during pregnancy that was managed actively with arginine and protein restriction with serial amino acid and fetal growth monitoring, resulting in an uncomplicated term live birth.
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Affiliation(s)
- Tomi Kanninen
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Elizabeth Bryant
- Department of Obstetrics and Gynecology, Huron Valley-Sinai Hospital, Commerce, Michigan, USA
| | - Celide Koerner
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Bernard Gonik
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, USA.
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19
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Balfoort BM, Buijs MJN, Ten Asbroek ALMA, Bergen AAB, Boon CJF, Ferreira EA, Houtkooper RH, Wagenmakers MAEM, Wanders RJA, Waterham HR, Timmer C, van Karnebeek CD, Brands MM. A review of treatment modalities in gyrate atrophy of the choroid and retina (GACR). Mol Genet Metab 2021; 134:96-116. [PMID: 34340878 DOI: 10.1016/j.ymgme.2021.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/02/2021] [Accepted: 07/23/2021] [Indexed: 12/29/2022]
Abstract
UNLABELLED Gyrate atrophy of the choroid and retina (GACR) is a rare inborn error of amino acid metabolism caused by bi-allelic variations in OAT. GACR is characterised by vision decline in early life eventually leading to complete blindness, and high plasma ornithine levels. There is no curative treatment for GACR, although several therapeutic modalities aim to slow progression of the disease by targeting different steps within the ornithine pathway. No international treatment protocol is available. We systematically collected all international literature on therapeutic interventions in GACR to provide an overview of published treatment effects. METHODS Following the PRISMA guidelines, we conducted a systematic review of the English literature until December 22nd 2020. PubMed and Embase databases were searched for studies related to therapeutic interventions in patients with GACR. RESULTS A total of 33 studies (n = 107 patients) met the inclusion criteria. Most studies were designed as case reports (n = 27) or case series (n = 4). No randomised controlled trials or large cohort studies were found. Treatments applied were protein-restricted diets, pyridoxine supplementation, creatine or creatine precursor supplementation, l-lysine supplementation, and proline supplementation. Protein-restricted diets lowered ornithine levels ranging from 16.0-91.2%. Pyridoxine responsiveness was reported in 30% of included mutations. Lysine supplementation decreased ornithine levels with 21-34%. Quality assessment showed low to moderate quality of the articles. CONCLUSIONS Based primarily on case reports ornithine levels can be reduced by using a protein restricted diet, pyridoxine supplementation (variation-dependent) and/or lysine supplementation. The lack of pre-defined clinical outcome measures and structural follow-up in all included studies impeded conclusions on clinical effectiveness. Future research should be aimed at 1) Unravelling the OAT biochemical pathway to identify other possible pathologic metabolites besides ornithine, 2) Pre-defining GACR specific clinical outcome measures, and 3) Establishing an international historical cohort.
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Affiliation(s)
- Berith M Balfoort
- Department of Paediatrics, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Mark J N Buijs
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Anneloor L M A Ten Asbroek
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Arthur A B Bergen
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands; Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands; Department of Ophthalmology, Leiden University Medical Centre, 2333, ZA, Leiden, the Netherlands
| | - Elise A Ferreira
- Department of Paediatrics, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Riekelt H Houtkooper
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Margreet A E M Wagenmakers
- Department of Internal Medicine, Centre for Lysosomal and Metabolic Diseases, Erasmus MC, University Medical Centre Rotterdam, the Netherlands
| | - Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Corrie Timmer
- Department Endocrinology and Metabolism Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Clara D van Karnebeek
- Department of Paediatrics, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands; Department of Paediatrics, Radboud Centre for Mitochondrial Medicine, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Marion M Brands
- Department of Paediatrics, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands.
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20
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Montioli R, Sgaravizzi G, Desbats MA, Grottelli S, Voltattorni CB, Salviati L, Cellini B. Molecular and Cellular Studies Reveal Folding Defects of Human Ornithine Aminotransferase Variants Associated With Gyrate Atrophy of the Choroid and Retina. Front Mol Biosci 2021; 8:695205. [PMID: 34395527 PMCID: PMC8360850 DOI: 10.3389/fmolb.2021.695205] [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: 04/14/2021] [Accepted: 07/01/2021] [Indexed: 11/13/2022] Open
Abstract
The deficit of human ornithine aminotransferase (hOAT) is responsible for gyrate atrophy (GA), a rare recessive inherited disorder. Although more than 60 disease-associated mutations have been identified to date, the molecular mechanisms explaining how each mutation leads to the deficit of OAT are mostly unknown. To fill this gap, we considered six representative missense mutations present in homozygous patients concerning residues spread over the hOAT structure. E. coli expression, spectroscopic, kinetic and bioinformatic analyses, reveal that the R154L and G237D mutations induce a catalytic more than a folding defect, the Q90E and R271K mutations mainly impact folding efficiency, while the E318K and C394Y mutations give rise to both folding and catalytic defects. In a human cellular model of disease folding-defective variants, although at a different extent, display reduced protein levels and/or specific activity, due to increased aggregation and/or degradation propensity. The supplementation with Vitamin B6, to mimic a treatment strategy available for GA patients, does not significantly improve the expression/activity of folding-defective variants, in contrast with the clinical responsiveness of patients bearing the E318K mutation. Thus, we speculate that the action of vitamin B6 could be also independent of hOAT. Overall, these data represent a further effort toward a comprehensive analysis of GA pathogenesis at molecular and cellular level, with important relapses for the improvement of genotype/phenotype correlations and the development of novel treatments.
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Affiliation(s)
- Riccardo Montioli
- Section of Biological Chemistry, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Giada Sgaravizzi
- Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Maria Andrea Desbats
- Clinical Genetics Unit, Department of Woman and Child Health, University of Padova, Padova, Italy
| | - Silvia Grottelli
- Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Carla Borri Voltattorni
- Section of Biological Chemistry, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Leonardo Salviati
- Clinical Genetics Unit, Department of Woman and Child Health, University of Padova, Padova, Italy
| | - Barbara Cellini
- Department of Medicine and Surgery, University of Perugia, Perugia, Italy
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Du J, Zhu S, Lim RR, Chao JR. Proline metabolism and transport in retinal health and disease. Amino Acids 2021; 53:1789-1806. [PMID: 33871679 PMCID: PMC8054134 DOI: 10.1007/s00726-021-02981-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/10/2021] [Indexed: 12/11/2022]
Abstract
The retina is one of the most energy-demanding tissues in the human body. Photoreceptors in the outer retina rely on nutrient support from the neighboring retinal pigment epithelium (RPE), a monolayer of epithelial cells that separate the retina and choroidal blood supply. RPE dysfunction or cell death can result in photoreceptor degeneration, leading to blindness in retinal degenerative diseases including some inherited retinal degenerations and age-related macular degeneration (AMD). In addition to having ready access to rich nutrients from blood, the RPE is also supplied with lactate from adjacent photoreceptors. Moreover, RPE can phagocytose lipid-rich outer segments for degradation and recycling on a daily basis. Recent studies show RPE cells prefer proline as a major metabolic substrate, and they are highly enriched for the proline transporter, SLC6A20. In contrast, dysfunctional or poorly differentiated RPE fails to utilize proline. RPE uses proline to fuel mitochondrial metabolism, synthesize amino acids, build the extracellular matrix, fight against oxidative stress, and sustain differentiation. Remarkably, the neural retina rarely imports proline directly, but it uptakes and utilizes intermediates and amino acids derived from proline catabolism in the RPE. Mutations of genes in proline metabolism are associated with retinal degenerative diseases, and proline supplementation is reported to improve RPE-initiated vision loss. This review will cover proline metabolism in RPE and highlight the importance of proline transport and utilization in maintaining retinal metabolism and health.
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Affiliation(s)
- Jianhai Du
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, 26506, USA. .,Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA. .,One Medical Center Dr, WVU Eye Institute, PO Box 9193, Morgantown, WV, 26505, USA.
| | - Siyan Zhu
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, 26506, USA.,Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Rayne R Lim
- Department of Ophthalmology, University of Washington, Seattle, WA, 98109, USA
| | - Jennifer R Chao
- Department of Ophthalmology, University of Washington, Seattle, WA, 98109, USA
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22
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Marques JP, Pereira P. Gyrate atrophy of the choroid and retina. Postgrad Med J 2021; 98:308. [PMID: 33688066 DOI: 10.1136/postgradmedj-2021-139807] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 02/02/2021] [Accepted: 02/12/2021] [Indexed: 11/04/2022]
Affiliation(s)
- João Pedro Marques
- University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal .,Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal.,Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal
| | - Pedro Pereira
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal
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23
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Montioli R, Bellezza I, Desbats MA, Borri Voltattorni C, Salviati L, Cellini B. Deficit of human ornithine aminotransferase in gyrate atrophy: Molecular, cellular, and clinical aspects. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1869:140555. [PMID: 33068755 DOI: 10.1016/j.bbapap.2020.140555] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 02/06/2023]
Abstract
Gyrate Atrophy (GA) of the choroid and retina (MIM# 258870) is an autosomal recessive disorder due to mutations of the OAT gene encoding ornithine-delta-aminotransferase (OAT), associated with progressive retinal deterioration and blindness. The disease has a theoretical global incidence of approximately 1:1,500,000. OAT is mainly involved in ornithine catabolism in adults, thus explaining the hyperornithinemia as hallmark of the disease. Patients are treated with an arginine-restricted diet, to limit ornithine load, or the administration of Vitamin B6, a precursor of the OAT coenzyme pyridoxal phosphate. Although the clinical and genetic aspects of GA are known for many years, the enzymatic phenotype of pathogenic variants and their response to Vitamin B6, as well as the molecular mechanisms explaining retinal damage, are poorly clarified. Herein, we provide an overview of the current knowledge on the biochemical properties of human OAT and on the molecular, cellular, and clinical aspects of GA.
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Affiliation(s)
- Riccardo Montioli
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, Verona, Italy
| | - Ilaria Bellezza
- Department of Experimental Medicine, Section of Physiology and Biochemistry, University of Perugia, Perugia, Italy
| | - Maria Andrea Desbats
- Clinical Genetics Unit, Department of Woman and Child Health, University of Padova, Padova, Italy
| | - Carla Borri Voltattorni
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, Verona, Italy
| | - Leonardo Salviati
- Clinical Genetics Unit, Department of Woman and Child Health, University of Padova, Padova, Italy.
| | - Barbara Cellini
- Department of Experimental Medicine, Section of Physiology and Biochemistry, University of Perugia, Perugia, Italy.
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Metabolism and Functions of Amino Acids in Sense Organs. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1265:201-217. [PMID: 32761578 DOI: 10.1007/978-3-030-45328-2_12] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Sense organs (eyes, ears, nose, tongue, and skin) provide senses of sight, hearing, smell, taste, and touch, respectively, to aid the survival, development, learning, and adaptation of humans and other animals (including fish). Amino acids (AAs) play an important role in the growth, development, and functions of the sense organs. Recent work has identified receptor-mediated mechanisms responsible for the chemosensory transduction of five basic taste qualities (sweet, sour, bitter, umami and salty tastes). Abnormal metabolism of AAs result in a structural deformity of tissues and their dysfunction. To date, there is a large database for AA metabolism in the eye and skin under normal (e.g., developmental changes and physiological responses) and pathological (e.g., nutritional and metabolic diseases, nutrient deficiency, infections, and cancer) conditions. Important metabolites of AAs include nitric oxide and polyamines (from arginine), melanin and dopamine (from phenylalanine and tyrosine), and serotonin and melatonin (from tryptophan) in both the eye and the skin; γ-aminobutyrate (from glutamate) in the retina; and urocanic acid and histamine (from histidine) in the skin. At present, relatively little is known about the synthesis or catabolism of AAs in the ears, nose, and tongue. Future research should be directed to: (1) address this issue with regard to healthy ageing, nasal and sinus cancer, the regulation of food intake, and oral cavity health; and (2) understand how prenatal and postnatal nutrition and environmental pollution affect the growth, development and health of the sense organs, as well as their expression of genes (including epigenetics) and proteins in humans and other animals.
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25
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Raval V, Kapoor A, Nayak S, Rao S, Das T. Optical Coherence Tomography Angiography and Macular Vessel Density Analysis of Cystoid Macular Edema in Gyrate Atrophy. Ophthalmic Surg Lasers Imaging Retina 2019; 50:423-427. [DOI: 10.3928/23258160-20190703-03] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 01/22/2019] [Indexed: 11/20/2022]
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26
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Palanza KM, Nesta AV, Tumu R, Walton CM, Davis MA, King TR. Auxotrophy-Based Detection of Hyperornithinemia in Mouse Blood and Urine. JOURNAL OF INBORN ERRORS OF METABOLISM AND SCREENING 2016. [DOI: 10.1177/2326409816649600] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Kenneth M. Palanza
- Biomolecular Sciences, Central Connecticut State University, New Britain, CT, USA
| | - Alex V. Nesta
- Biomolecular Sciences, Central Connecticut State University, New Britain, CT, USA
| | - Renukanandan Tumu
- Biomolecular Sciences, Central Connecticut State University, New Britain, CT, USA
| | - Cherie M. Walton
- Biomolecular Sciences, Central Connecticut State University, New Britain, CT, USA
| | - Michael A. Davis
- Biomolecular Sciences, Central Connecticut State University, New Britain, CT, USA
| | - Thomas R. King
- Biomolecular Sciences, Central Connecticut State University, New Britain, CT, USA
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27
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Peng Y, Cooper SK, Li Y, Mei JM, Qiu S, Borchert GL, Donald SP, Kung HF, Phang JM. Ornithine-δ-Aminotransferase Inhibits Neurogenesis During Xenopus Embryonic Development. Invest Ophthalmol Vis Sci 2015; 56:2486-97. [PMID: 25783604 DOI: 10.1167/iovs.15-16509] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE In humans, deficiency of ornithine-δ-aminotransferase (OAT) results in progressive degeneration of the neural retina (gyrate atrophy) with blindness in the fourth decade. In this study, we used the Xenopus embryonic developmental model to study functions of the OAT gene on embryonic development. METHODS We cloned and sequenced full-length OAT cDNA from Xenopus oocytes (X-OAT) and determined X-OAT expression in various developmental stages of Xenopus embryos and in a variety of adult tissues. The phenotype, gene expression of neural developmental markers, and enzymatic activity were detected by gain-of-function and loss-of-function manipulations. RESULTS We showed that X-OAT is essential for Xenopus embryonic development, and overexpression of X-OAT produces a ventralized phenotype characterized by a small head, lack of axial structure, and defective expression of neural developmental markers. Using X-OAT mutants based on mutations identified in humans, we found that substitution of both Arg 180 and Leu 402 abrogated both X-OAT enzymatic activity and ability to modulate the developmental phenotype. Neurogenesis is inhibited by X-OAT during Xenopus embryonic development. CONCLUSIONS Neurogenesis is inhibited by X-OAT during Xenopus embryonic development, but it is essential for Xenopus embryonic development. The Arg 180 and Leu 402 are crucial for these effects of the OAT molecule in development.
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Affiliation(s)
- Ying Peng
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Sandra K Cooper
- Basic Research Program, Leidos, Inc., National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland, United States
| | - Yi Li
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jay M Mei
- Metabolism and Cancer Susceptibility Section, Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland, United States
| | - Shuwei Qiu
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Gregory L Borchert
- Basic Research Program, Leidos, Inc., National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland, United States
| | - Steven P Donald
- Metabolism and Cancer Susceptibility Section, Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland, United States
| | - Hsiang-Fu Kung
- State Key Laboratory of Oncology in Southern China, and Centre for Emerging Infectious Diseases, the Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - James M Phang
- Metabolism and Cancer Susceptibility Section, Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland, United States
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28
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Kang S, Zhang Z, Richardson J, Shah B, Gupta S, Huang CJ, Qiu J, Le N, Lin H, Bondarenko PV. Metabolic markers associated with high mannose glycan levels of therapeutic recombinant monoclonal antibodies. J Biotechnol 2015; 203:22-31. [DOI: 10.1016/j.jbiotec.2015.03.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 02/28/2015] [Accepted: 03/05/2015] [Indexed: 01/21/2023]
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29
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Progression of gyrate atrophy measured with ultra-wide-field imaging. Int Ophthalmol 2015; 36:111-120. [DOI: 10.1007/s10792-015-0085-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 05/13/2015] [Indexed: 10/23/2022]
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30
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Sakamoto K, Mori A, Nakahara T, Morita M, Ishii K. Effect of Long-Term Treatment of L-Ornithine on Visual Function and Retinal Histology in the Rats. Biol Pharm Bull 2015; 38:139-43. [DOI: 10.1248/bpb.b14-00491] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Kenji Sakamoto
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences
| | - Asami Mori
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences
| | - Tsutomu Nakahara
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences
| | - Masahiko Morita
- Healthcare Products Development Center, Kyowa Hakko Bio Co., Ltd
| | - Kunio Ishii
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences
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31
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Bisaillon JJ, Radden LA, Szabo ET, Hughes SR, Feliciano AM, Nesta AV, Petrovic B, Palanza KM, Lancinskas D, Szmurlo TA, Artus DC, Kapper MA, Mulrooney JP, King TR. The retarded hair growth ( rhg) mutation in mice is an allele of ornithine aminotransferase ( Oat). Mol Genet Metab Rep 2014; 1:378-390. [PMID: 25264521 PMCID: PMC4171744 DOI: 10.1016/j.ymgmr.2014.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Because of the similar phenotypes they generate and their proximate reported locations on Chromosome 7, we tested the recessive retarded hair growth (rhg) and frizzy (fr) mouse mutations for allelism, but found instead that these defects complement. To discover the molecular basis of rhg, we analyzed a large intraspecific backcross panel that segregated for rhg and restricted this locus to a 0.9 Mb region that includes fewer than ten genes, only five of which have been reported to be expressed in skin. Complementation testing between rhg and a recessive null allele of fibroblast growth factor receptor 2 eliminated Fgfr2 as the possible basis of the retarded hair growth phenotype, but DNA sequencing of another of these candidates, ornithine aminotransferase (Oat), revealed a G to C transversion specifically associated with the rhg allele that would result in a glycine to alanine substitution at residue 353 of the gene product. To test whether this missense mutation might cause the mutant phenotype, we crossed rhg/rhg mice with mice that carried a recessive, perinatal-lethal, null mutation in Oat (designated OatΔ herein). Hybrid offspring that inherited both rhg and OatΔ displayed markedly delayed postnatal growth and hair development, indicating that these two mutations are allelic, and suggesting strongly that the G to C mutation in Oat is responsible for the retarded hair growth phenotype. Comparisons among +/+, +/rhg, rhg/rhg and rhg/OatΔ mice showed plasma ornithine levels and ornithine aminotransferase activities (in liver lysates) consistent with this assignment. Because histology of 7- and 12-month-old rhg/rhg and rhg/OatΔ retinas revealed chorioretinal degeneration similar to that described previously for OatΔ/OatΔ mice, we suggest that the rhg mutant may offer an ideal model for gyrate atrophy of the choroid and retina (GACR) in humans, which is also caused by the substitution of glycine 353 in some families. Genetic mapping identifies a small number of candidates for the mouse rhg mutation. Complementation testing between a null allele of Fgfr2 and rhg rules out allelism. A null allele of ornithine aminotransferase (Oat) fails to complement rhg. The rhg mutation results from a missense mutation in Oat. Mutant rhg/rhg mice show diminished OAT function, and chorioretinal degeneration.
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Affiliation(s)
- Jason J Bisaillon
- Biomolecular Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053, USA
| | - Legairre A Radden
- Biomolecular Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053, USA
| | - Eric T Szabo
- Biomolecular Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053, USA
| | - Samantha R Hughes
- Biomolecular Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053, USA
| | - Aaron M Feliciano
- Biomolecular Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053, USA
| | - Alex V Nesta
- Biomolecular Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053, USA
| | - Belinda Petrovic
- Biomolecular Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053, USA
| | - Kenneth M Palanza
- Biomolecular Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053, USA
| | - Dainius Lancinskas
- Biomolecular Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053, USA
| | - Theodore A Szmurlo
- Biomolecular Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053, USA
| | - David C Artus
- Biomolecular Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053, USA
| | - Martin A Kapper
- Biomolecular Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053, USA
| | - James P Mulrooney
- Biomolecular Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053, USA
| | - Thomas R King
- Biomolecular Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053, USA
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Casarano M, Alessandrì MG, Salomons GS, Moretti E, Jakobs C, Gibson KM, Cioni G, Battini R. Efficacy of vigabatrin intervention in a mild phenotypic expression of succinic semialdehyde dehydrogenase deficiency. JIMD Rep 2011; 2:119-23. [PMID: 23430864 DOI: 10.1007/8904_2011_60] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 04/11/2011] [Accepted: 04/12/2011] [Indexed: 04/07/2023] Open
Abstract
We report a patient with succinic semialdehyde dehydrogenase deficiency who presented a mild phenotype including developmental language delay, in association with the typical elevations of 4-hydroxybutyric acid (GHB) in biological fluids and MRI alterations. Two pathogenic mutations were identified one transversion (c.278 G>T) in exon 1 and another (c.1557 T>G) in exon 10. Both parents are carriers of one of the mutations, confirming compound-heterozygosity in their affected child. To reduce the GHB levels in body fluids, a treatment with vigabatrin at low dose (25 mg/kg per day) was started, monitoring its efficacy by clinical and neurochemical follow-up. After 9 months of therapy with vigabatrin, a significant reduction of GHB concentrations in urine and CSF was observed; after 36 months, a significant improvement of communicative skills, not previously reported, was referred. These results support the hypothesis that the clinical improvement is correlated to the reduction in the GHB levels and the importance of considering the SSADH deficiency in the differential diagnosis of patients with mental retardation and language delay.
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Affiliation(s)
- M Casarano
- Department of Developmental Neuroscience, IRCCS Stella Maris, Via dei Giacinti 2, 56118, Calambrone, Pisa, Italy
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Meyer JS, Howden SE, Wallace KA, Verhoeven AD, Wright LS, Capowski EE, Pinilla I, Martin JM, Tian S, Stewart R, Pattnaik B, Thomson J, Gamm DM. Optic vesicle-like structures derived from human pluripotent stem cells facilitate a customized approach to retinal disease treatment. Stem Cells 2011; 29:1206-18. [PMID: 21678528 PMCID: PMC3412675 DOI: 10.1002/stem.674] [Citation(s) in RCA: 346] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Differentiation methods for human induced pluripotent stem cells (hiPSCs) typically yield progeny from multiple tissue lineages, limiting their use for drug testing and autologous cell transplantation. In particular, early retina and forebrain derivatives often intermingle in pluripotent stem cell cultures, owing to their shared ancestry and tightly coupled development. Here, we demonstrate that three-dimensional populations of retinal progenitor cells (RPCs) can be isolated from early forebrain populations in both human embryonic stem cell and hiPSC cultures, providing a valuable tool for developmental, functional, and translational studies. Using our established protocol, we identified a transient population of optic vesicle (OV)-like structures that arose during a time period appropriate for normal human retinogenesis. These structures were independently cultured and analyzed to confirm their multipotent RPC status and capacity to produce physiologically responsive retinal cell types, including photoreceptors and retinal pigment epithelium (RPE). We then applied this method to hiPSCs derived from a patient with gyrate atrophy, a retinal degenerative disease affecting the RPE. RPE generated from these hiPSCs exhibited a disease-specific functional defect that could be corrected either by pharmacological means or following targeted gene repair. The production of OV-like populations from human pluripotent stem cells should facilitate the study of human retinal development and disease and advance the use of hiPSCs in personalized medicine.
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Affiliation(s)
- Jason S. Meyer
- Waisman Center, University of Wisconsin, Madison WI 53705
| | - Sara E. Howden
- Department of Cell & Regenerative Biology, University of Wisconsin, Madison WI 53705
- The Genome Center of Wisconsin, University of Wisconsin, Madison WI 53705
- Morgridge Institute for Research, Madison WI 53706
| | | | | | | | | | - Isabel Pinilla
- Department of Ophthalmology, Blesa University Hospital and the Instituto Aragones de Ciencias de la Salud, Zaragoza, Spain
| | | | - Shulan Tian
- Morgridge Institute for Research, Madison WI 53706
| | - Ron Stewart
- Morgridge Institute for Research, Madison WI 53706
| | - Bikash Pattnaik
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison WI 53705
- Department of Pediatrics, University of Wisconsin, Madison WI 53705
- Eye Research Institute, University of Wisconsin, Madison WI 53705
| | - James Thomson
- Department of Cell & Regenerative Biology, University of Wisconsin, Madison WI 53705
- The Genome Center of Wisconsin, University of Wisconsin, Madison WI 53705
- Morgridge Institute for Research, Madison WI 53706
- Department of Molecular, Cellular, & Developmental Biology, University of California Santa Barbara, Santa Barbara CA 93106
| | - David M. Gamm
- Waisman Center, University of Wisconsin, Madison WI 53705
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison WI 53705
- Eye Research Institute, University of Wisconsin, Madison WI 53705
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Abstract
We reviewed the literature on ornithine supplementation and related topics. Nutritionists and physicians have reported that ornithine supplementation is useful. Paediatricians and biochemists have reported that ornithine is supplemented for NH3detoxification in the hyperornithinaemia–hyperammonaemia–homocitrullinuria (HHH) syndrome. In contrast, ophthalmic researchers have reported retinotoxicity associated with high-dose ornithine.In vivoandin vitroexperiments have shown that high concentrations of ornithine or its metabolites are toxic to the retinal pigment epithelial (RPE) cells. Long-term (exceeding a few years) and high concentrations (exceeding 600 μmol/l) of ornithine in the blood induce retinal toxicity in gyrate atrophy of the choroid and retina (GA). Intermittent high levels of ornithine do not lead to retinal lesions. Constant blood ornithine levels between 250 and 600 μmol/l do not induce retinal lesions or cause a very slowly progressive retinal degeneration. Blood ornithine levels below 250 μmol/l do not produce retinal alteration. We concluded that short-term, low-dose or transient high-dose ornithine intake is safe for the retina; its nutritional usefulness and effect on NH3detoxification are supported by many researchers, but the effect may be limited; and long-term, high-dose ornithine intake may be risky for the retina. Patients with GA should avoid taking ornithine; amino acid supplementation should be administered carefully for patients with the HHH syndrome, relatives of patients with GA (heterozygotes) and subjects with RPE lesions; and blood ornithine levels and retinal conditions should be evaluated in individuals taking long-term, high-dose ornithine.
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35
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Poll-The BT, Maillette de Buy Wenniger-Prick CJ. The eye in metabolic diseases: clues to diagnosis. Eur J Paediatr Neurol 2011; 15:197-204. [PMID: 21511505 DOI: 10.1016/j.ejpn.2011.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 03/20/2011] [Indexed: 11/17/2022]
Abstract
Ophthalmologic manifestations occur in various inborn errors of metabolism (IEM), including small molecule disorders and organelle disorders. In a minority of diseases the occurrence of eye abnormalities could be attributed to direct toxic mechanisms of abnormal metabolic products or accumulation of normal metabolites by errors of synthetic pathways or by deficient energy metabolism. The age of onset of ocular abnormalities in IEM is variable, but onset often begins from birth to childhood. The major IEM associated with eye abnormalities include errors of lipid metabolism, carbohydrate metabolism, protein metabolism, and metal metabolism. IEM disorders with ocular motor manifestations include lipid storage diseases, neurotransmitter disorders and respiratory chain disorders. The purpose of this article is to describe ocular phenotypes associated with IEM, focusing on those diseases in which the ocular involvement is seen relatively early in the course of the disease. As therapeutic approaches become available for certain groups of IEM, the need for early diagnosis is increasingly important.
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Affiliation(s)
- B T Poll-The
- Academic Medical Center, Department of Pediatric Neurology Emma Children's Hospital (H7-282), PO Box 22660, 1100 DD Amsterdam, The Netherlands.
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Sorri I, Brigell MG, Mályusz M, Mahlamäki E, de Meynard C, Kälviäinen R. Is reduced ornithine-δ-aminotransferase activity the cause of vigabatrin-associated visual field defects? Epilepsy Res 2010; 92:48-53. [PMID: 20850272 DOI: 10.1016/j.eplepsyres.2010.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2010] [Revised: 07/24/2010] [Accepted: 08/15/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND A gabaergic antiepileptic drug, vigabatrin (VGB), is known to induce bilateral concentric visual field defects (VFD) in 30-40% of treated patients. Although the clinical and electrophysiological features of VFDs are well documented, the mechanism of retinal toxicity is still unclear. PURPOSE To determine if low basal ornithine-δ-aminotranspherase (OAT) activity is implicated in the etiology of VGB retinotoxicity, resulting in a phenotype of a mild form of gyrate atrophy. METHODS Assays of OAT activity in lymphocytes and GABA-transaminase activity in platelets were performed, and plasma levels of GABA, ornithine, lysine, glutamic acid and glutamine were measured, and visual fields were examined. A total of 47 subjects, aged 14-78 years, were examined. Twenty-one epileptic patients were off VGB more than 1 year; 11 patients with VGB-induced VFD and 10 with normal visual fields. Ten epileptic patients were on current VGB therapy more than 1 year; four patients with VGB-induced VFD and six with normal visual fields. The results were compared with those of 10 epilepsy patients taking tiagabine and six patients who suffered from gyrate atrophy (GA) or were obligate carriers of the disease. RESULTS In patients who had stopped VGB and who had VFDs, OAT activity was significantly reduced as compared with those who had normal visual fields (77.4pmol P5C/min/mgPro vs. 181.9pmol P5C/min/mgPro, p=0.002). In patients with ongoing VGB therapy, no difference was found between the patients with and without VFDs (149.4pmol P5C/min/mgPro vs. 159.1pmol P5C/min/mgPro). CONCLUSIONS : The results suggest that VGB retinotoxicity might be associated with elevated retinal ornithine mediated by low basal OAT activity.
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Affiliation(s)
- Iiris Sorri
- Department of Ophthalmology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland.
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Grover S, Fishman GA. Choroidal Dystrophies. Ophthalmology 2009. [DOI: 10.1016/b978-0-323-04332-8.00085-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Fleury M, Barbier R, Ziegler F, Mohr M, Caron O, Dollfus H, Tranchant C, Warter JM. Myopathy with tubular aggregates and gyrate atrophy of the choroid and retina due to hyperornithinaemia. J Neurol Neurosurg Psychiatry 2007; 78:656-7. [PMID: 17088329 PMCID: PMC2077941 DOI: 10.1136/jnnp.2006.101386] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Do DV, Zhang K, Garibaldi DC, Carr RE, Sunness JS. Hereditary Choroidal Disease. Retina 2006. [DOI: 10.1016/b978-0-323-02598-0.50024-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Roh GS, Shin Y, Seo SW, Yoon BR, Yeo S, Park SJ, Cho JW, Kwack K. Proteome analysis of differential protein expression in allergen-induced asthmatic mice lung after dexamethasone treatment. Proteomics 2005; 4:3318-27. [PMID: 15378748 DOI: 10.1002/pmic.200400930] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Asthma has become substantially more prevalent in recent decades and is one of the foremost contributors to morbidity and mortality in industrialized countries. Corticosteroids are among the most effective medications for the treatment of asthma, but some patients do not respond well to corticosteroid treatment. In this study, we characterized the responses to an allergen and identified potential molecular targets of dexamethasone (Dex) treatment in acute asthma. Female BALB/c mice sensitized to ovalbumin (OVA) were challenged with aerosolized OVA for 1 week. During the challenge period, mice were treated daily with Dex by intraperitoneal injection. Phosphate-buffered saline treated and non-challenged mice served as control. Histological evaluation of OVA-induced mice revealed airway inflammation and goblet cell hyperplasia. In addition, interleukin 4 levels and interferon-gamma levels were increased and decreased, respectively. These changes were moderated by Dex treatment. Protein expression profiles were compared in each experimental group by two-dimensional gel electrophoresis and identified using matrix-assisted laser desorption/ionization-time of flight/time of flight mass spectrometry. Some proteins were increased, while others were decreased by Dex treatment. These results indicated that the regulation of protein expression might play a role in the immunological and pathological development of asthma and could be targeted for therapeutic intervention. These results may assist in the development of quantitative diagnostic markers to monitor disease progression or responses to therapy using proteomic approaches.
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Affiliation(s)
- Gu Seob Roh
- National Genome Research Institute, National Institute of Health, Seoul, Korea
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41
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Kalloniatis M, Fletcher EL. Retinitis pigmentosa: understanding the clinical presentation, mechanisms and treatment options. Clin Exp Optom 2004; 87:65-80. [PMID: 15040773 DOI: 10.1111/j.1444-0938.2004.tb03152.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Revised: 02/09/2004] [Indexed: 11/27/2022] Open
Abstract
Retinitis pigmentosa (RP) is a leading cause of human blindness due to degeneration of retinal photoreceptor cells. Causes of retinal degeneration include defects in the visual pigment, defects in the proteins important for photoreceptor function or in enzymes involved in initiating visual transduction. Despite the diversity of genetic mutations identified in inherited forms of retinal dystrophy, there is a common end result of photoreceptor death and functional blindness. In this review, pertinent anatomical and physiological pathways involved in RP and the underlying genetic mutations are outlined, including a discussion on the inheritance patterns revealed by advances in molecular biological techniques. Characteristics of progression rates of visual field loss and current management options will provide useful clinical guidelines for the management of patients with RP.
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Affiliation(s)
- Michael Kalloniatis
- Department of Optometry and Vision Science, University of Auckland, Private Bag 92019, Auckland, New Zealand
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Santinelli R, Costagliola C, Tolone C, D'Aloia A, D'Avanzo A, Prisco F, Perrone L, del Giudice EM. Low-protein diet and progression of retinal degeneration in gyrate atrophy of the choroid and retina: a twenty-six-year follow-up. J Inherit Metab Dis 2004; 27:187-96. [PMID: 15159649 DOI: 10.1023/b:boli.0000028779.29966.05] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Gyrate atrophy of the choroid and retina is an autosomal recessive chorioretinal dystrophy which leads to a slowly progressive loss of vision. The primary defect is due to a deficiency of the enzyme ornithine delta-aminotransferase, which is responsible for markedly elevated levels of ornithine in plasma and other body fluids. Although several therapeutic regimens have been proposed, the reduction in ornithine accumulation obtained by reducing the intake of its precursor arginine (semisynthetic low-arginine diet) is the one most practised. In this clinical and molecular study we report a patient with hyperornithinaemia and gyrate atrophy of the choroid and retina who had been diagnosed when she was 3 years 9 months old. She also presented mild mental retardation, delayed language development and speech defects. The patient has recently been found to be homozygous for the new Gly91Arg amino acid substitution of the enzyme ornithine delta-aminotransferase. This mutation lies in a region of the mature protein that is considered crucial for the mitochondrial targeting activity. In this patient, a 28-year treatment with a completely natural low-protein diet (0.8 g/kg per day of natural protein) has been able to significantly reduce ornithine plasma levels, and to greatly delay the natural progression of the chorioretinal changes. This study suggests that, in the long-term treatment of gyrate atrophy, the efficacy in slowing the progression of chorioretinal changes and the palatability of a completely natural low-protein diet make this treatment a potentially viable alternative in patients refusing the semisynthetic diet.
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Affiliation(s)
- R Santinelli
- Department of Pediatrics, Second University of Naples, Naples, Italy
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Poll-The BT, Maillette de Buy Wenniger-Prick LJ, Barth PG, Duran M. The eye as a window to inborn errors of metabolism. J Inherit Metab Dis 2003; 26:229-44. [PMID: 12889663 DOI: 10.1023/a:1024493318913] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Ocular manifestations in inborn errors of metabolism occur in many diseases and may be associated with any part of all eye components. In a minority of diseases it is possible to attribute the eye symptoms to a single hereditary pathogenetic mechanism. More often the aetiological relationship of the ocular defects to the metabolic disease is unknown. Diverse pathogenetic mechanisms may act via a common pathological pathway inducing ocular damage. The occurrence of eye abnormalities in metabolic disorders suggests that they are associated with direct toxic actions, errors of synthetic pathways or deficient energy metabolism. In this review, metabolic disorders with major abnormalities in the cornea, lens, retina and optic nerve are presented. In all cases, an appropriate combined approach by the ophthalmologist, paediatrician/neurologist, geneticist and clinical biochemist is the only way to diagnostic success.
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Affiliation(s)
- B T Poll-The
- Department of Pediatrics/Emma Children's Hospital and Laboratory of Genetic Metabolic Diseases, Amsterdam, The Netherlands.
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Flynn NE, Meininger CJ, Haynes TE, Wu G. The metabolic basis of arginine nutrition and pharmacotherapy. Biomed Pharmacother 2002; 56:427-38. [PMID: 12481979 DOI: 10.1016/s0753-3322(02)00273-1] [Citation(s) in RCA: 208] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
As an essential precursor for the synthesis of proteins and other molecules with enormous biological importance (including nitric oxide, urea, ornithine, proline, polyamines, glutamate, creatine, agmatine, and dimethylarginines), arginine displays remarkable metabolic and regulatory versatility. Evidence available to date provides a sound reason to classify arginine as an essential amino acid for young mammals (including parenterally fed human infants) and as a conditionally essential amino acid for adults under such conditions as trauma, burn injury, massive small-bowel resection, and renal failure. Arginine administration reverses endothelial dysfunction, enhances wound healing, prevents the early stages of tumorigenesis, and improves cardiovascular, reproductive, pulmonary, renal, digestive, and immune functions. Arginine or its effective precursor citrulline may hold great promise as a nutritional or pharmacotherapeutic treatment for a wide array of human diseases.
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Affiliation(s)
- N E Flynn
- Department of Chemistry and Biochemistry, Angelo State University, San Angelo, TX 76909, USA.
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Ames BN, Elson-Schwab I, Silver EA. High-dose vitamin therapy stimulates variant enzymes with decreased coenzyme binding affinity (increased K(m)): relevance to genetic disease and polymorphisms. Am J Clin Nutr 2002; 75:616-58. [PMID: 11916749 DOI: 10.1093/ajcn/75.4.616] [Citation(s) in RCA: 218] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
As many as one-third of mutations in a gene result in the corresponding enzyme having an increased Michaelis constant, or K(m), (decreased binding affinity) for a coenzyme, resulting in a lower rate of reaction. About 50 human genetic dis-eases due to defective enzymes can be remedied or ameliorated by the administration of high doses of the vitamin component of the corresponding coenzyme, which at least partially restores enzymatic activity. Several single-nucleotide polymorphisms, in which the variant amino acid reduces coenzyme binding and thus enzymatic activity, are likely to be remediable by raising cellular concentrations of the cofactor through high-dose vitamin therapy. Some examples include the alanine-to-valine substitution at codon 222 (Ala222-->Val) [DNA: C-to-T substitution at nucleo-tide 677 (677C-->T)] in methylenetetrahydrofolate reductase (NADPH) and the cofactor FAD (in relation to cardiovascular disease, migraines, and rages), the Pro187-->Ser (DNA: 609C-->T) mutation in NAD(P):quinone oxidoreductase 1 [NAD(P)H dehy-drogenase (quinone)] and FAD (in relation to cancer), the Ala44-->Gly (DNA: 131C-->G) mutation in glucose-6-phosphate 1-dehydrogenase and NADP (in relation to favism and hemolytic anemia), and the Glu487-->Lys mutation (present in one-half of Asians) in aldehyde dehydrogenase (NAD + ) and NAD (in relation to alcohol intolerance, Alzheimer disease, and cancer).
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Affiliation(s)
- Bruce N Ames
- Department of Molecular and Cellular Biology, University of California, Berkeley, USA.
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Hisama FM, Mattson RH, Lee HH, Felice K, Petroff OA. GABA and the ornithine delta-aminotransferase gene in vigabatrin-associated visual field defects. Seizure 2001; 10:505-7. [PMID: 11749107 DOI: 10.1053/seiz.2001.0524] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Vigabatrin use in some epilepsy patients has been associated with persistent visual field constriction and retinal dysfunction. The mechanism is unknown, but could be related to vigabatrin, chronic epilepsy, GABA toxicity, or the effect of a metabolite in combination with a predisposing genotype. The aim of this study was to investigate the latter two hypotheses. Levels of brain gamma-aminobutyric acid (GABA) measured by nuclear magnetic resonance spectroscopy were similar in subjects taking vigabatrin who developed visual field constriction and those who did not. We tested whether allelic heterogeneity of the ornithine aminotransferase gene occurs in the affected patients. No clinically significant mutation was detected, although a common intronic polymorphism was identified.
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Affiliation(s)
- F M Hisama
- Department of Neurology, Yale University School of Medicine, P.O. Box 208018, 333 Cedar St., New Haven, CT, USA.
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Elpeleg N, Korman SH. Sustained oral lysine supplementation in ornithine delta-aminotransferase deficiency. J Inherit Metab Dis 2001; 24:423-4. [PMID: 11486915 DOI: 10.1023/a:1010545811361] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Oral lysine administration to three patients with B6-nonresponsive gyrate atrophy reduced plasma ornithine concentrations by 21-31% within 1-2 days. No further reduction was noted with time.
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Affiliation(s)
- N Elpeleg
- Metabolic Disease Unit, Shaare-Zedek Medical Center, Jerusalem, Israel.
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48
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Peltola KE, Näntö-Salonen K, Heinonen OJ, Jääskeläinen S, Heinänen K, Simell O, Nikoskelainen E. Ophthalmologic heterogeneity in subjects with gyrate atrophy of choroid and retina harboring the L402P mutation of ornithine aminotransferase. Ophthalmology 2001; 108:721-9. [PMID: 11297489 DOI: 10.1016/s0161-6420(00)00587-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
OBJECTIVE/PURPOSE To investigate clinical variation in a genetically homogenous group of subjects with gyrate atrophy of choroid and retina with hyperornithinemia (GA). The group was made up of homozygotes and compound heterozygotes for mutation L402P in the ornithine aminotransferase (OAT) gene. DESIGN Cross-sectional study. PARTICIPANTS Thirty-five Finnish subjects (18 men) with GA with a mean age of 33 years (range, 5-74 years) carrying the Finnish founder mutation L402P. METHODS All subjects were examined between 1993 and 1995. The analysis was composed of, in addition to careful clinical evaluation, studies of visual fields with Goldmann perimeter, photographing of the eye fundi, and corneal electroretinography (ERG) recordings. MAIN OUTCOME MEASURES The changes in eye fundi, visual acuity, cataract changes in the lens, visual field constriction, and ERG responses were determined. RESULTS Myopia, early cataracts, and highly abnormal ERG were typical for the GA subjects. The changes progressed rather uniformly with age. However, visual acuity, funduscopic findings, and visual fields showed great phenotypic variation. Despite the great interindividual variation, both eyes of each subject were always similarly affected. CONCLUSIONS This study of 35 subjects with GA carrying a single mutation shows that the ophthalmologic symptoms and findings vary widely. The data also reveal that GA subjects are already affected by severe visual impairment in young adulthood. However, the diagnosis is often made very late.
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Affiliation(s)
- K E Peltola
- Department of Pediatrics, University of Turku, Kiinamyllynkatu 10, FIN-20520 Turku, Finland.
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