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Knöpfel EB, Vilches C, Camargo SMR, Errasti-Murugarren E, Stäubli A, Mayayo C, Munier FL, Miroshnikova N, Poncet N, Junza A, Bhattacharya SS, Prat E, Berry V, Berger W, Heon E, Moore AT, Yanes Ó, Nunes V, Palacín M, Verrey F, Kloeckener-Gruissem B. Dysfunctional LAT2 Amino Acid Transporter Is Associated With Cataract in Mouse and Humans. Front Physiol 2019; 10:688. [PMID: 31231240 PMCID: PMC6558864 DOI: 10.3389/fphys.2019.00688] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 05/16/2019] [Indexed: 11/13/2022] Open
Abstract
Cataract, the loss of ocular lens transparency, accounts for ∼50% of worldwide blindness and has been associated with water and solute transport dysfunction across lens cellular barriers. We show that neutral amino acid antiporter LAT2 (Slc7a8) and uniporter TAT1 (Slc16a10) are expressed on mouse ciliary epithelium and LAT2 also in lens epithelium. Correspondingly, deletion of LAT2 induced a dramatic decrease in lens essential amino acid levels that was modulated by TAT1 defect. Interestingly, the absence of LAT2 led to increased incidence of cataract in mice, in particular in older females, and a synergistic effect was observed with simultaneous lack of TAT1. Screening SLC7A8 in patients diagnosed with congenital or age-related cataract yielded one homozygous single nucleotide deletion segregating in a family with congenital cataract. Expressed in HeLa cells, this LAT2 mutation did not support amino acid uptake. Heterozygous LAT2 variants were also found in patients with cataract some of which showed a reduced transport function when expressed in HeLa cells. Whether heterozygous LAT2 variants may contribute to the pathology of cataract needs to be further investigated. Overall, our results suggest that defects of amino acid transporter LAT2 are implicated in cataract formation, a situation that may be aggravated by TAT1 defects.
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Affiliation(s)
- Emilia Boiadjieva Knöpfel
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
- Swiss National Centre of Competence in Research Kidney.CH, University of Zurich, Zurich, Switzerland
| | - Clara Vilches
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory – IDIBELL, Barcelona, Spain
- U730 and U731, Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
| | - Simone M. R. Camargo
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Ekaitz Errasti-Murugarren
- U730 and U731, Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Andrina Stäubli
- Institute of Medical Molecular Genetics, University of Zurich, Zurich, Switzerland
- Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Clara Mayayo
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory – IDIBELL, Barcelona, Spain
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Francis L. Munier
- Jules-Gonin Eye Hospital, University of Lausanne, Lausanne, Switzerland
| | | | - Nadège Poncet
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Alexandra Junza
- Metabolomics Platform, IISPV, Department of Electronic Engineering, Universitat Rovira i Virgili, Tarragona, Spain
- CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Madrid, Spain
| | - Shomi S. Bhattacharya
- Andalusian Molecular Biology and Regenerative Medicine Centre – CABIMER, Seville, Spain
- UCL Institute of Ophthalmology, London, United Kingdom
| | - Esther Prat
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory – IDIBELL, Barcelona, Spain
- U730 and U731, Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
- Genetics Section, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
| | - Vanita Berry
- Andalusian Molecular Biology and Regenerative Medicine Centre – CABIMER, Seville, Spain
| | - Wolfgang Berger
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
- Institute of Medical Molecular Genetics, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich – ZNZ, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Elise Heon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON, Canada
| | - Anthony T. Moore
- Andalusian Molecular Biology and Regenerative Medicine Centre – CABIMER, Seville, Spain
- Moorfields Eye Hospital, London, United Kingdom
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Óscar Yanes
- Metabolomics Platform, IISPV, Department of Electronic Engineering, Universitat Rovira i Virgili, Tarragona, Spain
- CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Madrid, Spain
| | - Virginia Nunes
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory – IDIBELL, Barcelona, Spain
- U730 and U731, Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
- Genetics Section, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
| | - Manuel Palacín
- U730 and U731, Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
- Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Francois Verrey
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
- Swiss National Centre of Competence in Research Kidney.CH, University of Zurich, Zurich, Switzerland
| | - Barbara Kloeckener-Gruissem
- Institute of Medical Molecular Genetics, University of Zurich, Zurich, Switzerland
- Department of Biology, ETH Zurich, Zurich, Switzerland
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