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Vlasits AL, Syeda M, Wickman A, Guzman P, Schmidt TM. Atypical retinal function in a mouse model of Fragile X syndrome. bioRxiv 2024:2024.03.15.585283. [PMID: 38559003 PMCID: PMC10980068 DOI: 10.1101/2024.03.15.585283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Altered function of peripheral sensory neurons is an emerging mechanism for symptoms of autism spectrum disorders. Visual sensitivities are common in autism, but whether differences in the retina might underlie these sensitivities is not well-understood. We explored retinal function in the Fmr1 knockout model of Fragile X syndrome, focusing on a specific type of retinal neuron, the "sustained On alpha" retinal ganglion cell. We found that these cells exhibit changes in dendritic structure and dampened responses to light in the Fmr1 knockout. We show that decreased light sensitivity is due to increased inhibitory input and reduced E-I balance. The change in E-I balance supports maintenance of circuit excitability similar to what has been observed in cortex. These results show that loss of Fmr1 in the mouse retina affects sensory function of one retinal neuron type. Our findings suggest that the retina may be relevant for understanding visual function in Fragile X syndrome.
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Affiliation(s)
- Anna L Vlasits
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
- Department of Ophthalmology, University of Illinois, Chicago, IL, USA
- Lead contact
| | - Maria Syeda
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Annelise Wickman
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Pedro Guzman
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Tiffany M Schmidt
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
- Department of Ophthalmology, Feinberg School of Medicine, Chicago, IL, USA
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Ardourel M, Ranchon-Cole I, Pâris A, Felgerolle C, Acar N, Lesne F, Briault S, Perche O. FMR protein: Evidence of an emerging role in retinal aging? Exp Eye Res 2022; 225:109282. [PMID: 36265576 DOI: 10.1016/j.exer.2022.109282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 10/05/2022] [Accepted: 10/11/2022] [Indexed: 12/29/2022]
Abstract
Aging is a multifactorial process that affects the entire organism by cumulative alterations. Visual function impairments that go along with aging are commonly observed, causing lower visual acuity, lower contrast sensitivity, and impaired dark adaptation. Electroretinogram analysis revealed that the amplitudes of rod- and cone-mediated responses are reduced in aged mice and humans. Reports suggested that age-related changes observed in both rod and cone photoreceptor functionality were linked to oxidative stress regulation or free radical production homeostasis. Interestingly, several recent reports linked the fragile X mental retardation protein (FMRP) cellular activity with oxidative stress regulation in several tissue including brain tissue where FMRP participates to the response to stress via protein translation in neurite or is involved in free radical production and abnormal glutathione homeostasis. Based on these recent literatures, we raised the question about the effect of FMRP absence in the aging retina of Fmr1-/y compared to their WT littermates. Indeed, up to now, only young or adult mice (<6 months) were investigated and have shown a specific retinal phenotype. Herein, we demonstrated that Fmr1-/y mice do not present the aging effect on retinal function observed in WT littermates since ERG a- and b-waves amplitudes as well as oscillatory potentials amplitudes were not collapsed with age (12/18 months old). Absence of FMRP and its consequences seem to protect the retina against aging effect, rising a pivotal role of FMRP in retinal aging process.
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Affiliation(s)
- M Ardourel
- UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, 45071, Orléans, Cedex 2, France
| | - I Ranchon-Cole
- Université Clermont Auvergne, CHU Clermont-Ferrand, Inserm, Neuro-Dol, F-63000, Clermont-Ferrand, France
| | - A Pâris
- UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, 45071, Orléans, Cedex 2, France
| | - C Felgerolle
- UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, 45071, Orléans, Cedex 2, France
| | - N Acar
- Eye and Nutrition Research Group, Centre des Sciences du Goût et de l'Alimentation, CNRS, INRAE, Institut Agro, Université Bourgogne Franche-Comté, 21000, Dijon, France
| | - F Lesne
- Genetic Department, Regional Hospital, 14 Avenue de l'hôpital, 45100, Orléans, France
| | - S Briault
- UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, 45071, Orléans, Cedex 2, France; Genetic Department, Regional Hospital, 14 Avenue de l'hôpital, 45100, Orléans, France
| | - O Perche
- UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, 45071, Orléans, Cedex 2, France; Genetic Department, Regional Hospital, 14 Avenue de l'hôpital, 45100, Orléans, France.
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Ardourel M, Pâris A, Felgerolle C, Lesne F, Ranchon-Cole I, Briault S, Perche O. FMRP-related retinal phenotypes: Evidence of glutamate-glutamine metabolic cycle impairment. Exp Eye Res 2022; 224:109238. [PMID: 36067823 DOI: 10.1016/j.exer.2022.109238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/16/2022] [Accepted: 08/29/2022] [Indexed: 11/18/2022]
Abstract
FMRP, the fragile X mental retardation protein coded by the FMR1 gene, is an RNA-binding protein that assists transport, stabilization and translational regulation of specific synaptic mRNAs. Its expression has been found in multiple cell types of central nervous system (CNS) including glial cells where its involvement in glutamate neurotransmitter homeostasis have been shown. Indeed, glutamate homeostasis deficit has been observed in absence of FMRP in-vivo in cortex and hippocampus structures as well as in vitro on astroglial cell culture. Interestingly, the retina which is an extension of the CNS is presenting electrophysiological alterations in absence of FMRP in both human and murine models suggesting neurotransmitter impairments. Therefore, we investigate the consequences of Fmrp absence on Glutamate-Glutamine cycle in whole retinas and primary retinal Müller cells culture which are the main glial cells of the retina. Using the Fmr1-/y mice, we have shown in vivo and in vitro that the absence of Fmrp in Müller cells is characterized by loss of Glutamate-Glutamine cycle homeostasis due to a lower Glutamine Synthetase protein expression and activity. The lack of Fmrp in the retina induces a reduced flow of glutamine synthesis. Our data established for the first time in literature a direct link between the lack of Fmrp and neurotransmitter homeostasis in the retina.
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Affiliation(s)
- Maryvonne Ardourel
- UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, F-45071, Orléans Cedex 2, France
| | - Arnaud Pâris
- UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, F-45071, Orléans Cedex 2, France
| | - Chloé Felgerolle
- UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, F-45071, Orléans Cedex 2, France
| | - Fabien Lesne
- Genetic Department, Regional Hospital, 14 Avenue de l'hôpital, 45100, Orléans, France
| | - Isabelle Ranchon-Cole
- Université Clermont Auvergne, CHU Clermont-Ferrand, Inserm, Neuro-Dol, F-63000, Clermont-Ferrand, France
| | - Sylvain Briault
- Genetic Department, Regional Hospital, 14 Avenue de l'hôpital, 45100, Orléans, France; UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, F-45071, Orléans Cedex 2, France
| | - Olivier Perche
- Genetic Department, Regional Hospital, 14 Avenue de l'hôpital, 45100, Orléans, France; UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, F-45071, Orléans Cedex 2, France.
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