1
|
Kulbay M, Wu KY, Nirwal GK, Bélanger P, Tran SD. The Role of Reactive Oxygen Species in Age-Related Macular Degeneration: A Comprehensive Review of Antioxidant Therapies. Biomedicines 2024; 12:1579. [PMID: 39062152 PMCID: PMC11274723 DOI: 10.3390/biomedicines12071579] [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: 05/31/2024] [Revised: 06/26/2024] [Accepted: 07/12/2024] [Indexed: 07/28/2024] Open
Abstract
This review article delves into the intricate roles of reactive oxygen species (ROS) in the pathogenesis of age-related macular degeneration (AMD). It presents a detailed analysis of the oxidative stress mechanisms that contribute to the development and progression of these diseases. The review systematically explores the dual nature of ROS in ocular physiology and pathology, underscoring their essential roles in cellular signaling and detrimental effects when in excess. In the context of AMD, the focus is on the oxidative impairment in the retinal pigment epithelium and Bruch's membrane, culminating in the deterioration of macular health. Central to this review is the evaluation of various antioxidant strategies in the prevention and management of AMD. It encompasses a wide spectrum of antioxidants, ranging from dietary nutrients like vitamins C and E, lutein, and zeaxanthin to pharmacological agents with antioxidative properties. The review also addresses novel therapeutic approaches, including gene therapy and nanotechnology-based delivery systems, aiming to enhance antioxidant defense mechanisms in ocular tissues. The article concludes by synthesizing current research findings, clinical trial data, and meta-analyses to provide evidence-based recommendations. It underscores the need for further research to optimize antioxidant therapies, considering individual patient factors and disease stages. This comprehensive review thus serves as a valuable resource for clinicians, researchers, and healthcare professionals in ophthalmology, offering insights into the potential of antioxidants in mitigating the burden of AMD.
Collapse
Affiliation(s)
- Merve Kulbay
- Department of Ophthalmology & Visual Sciences, McGill University, Montréal, QC H4A 3S5, Canada;
| | - Kevin Y. Wu
- Division of Ophthalmology, Department of Surgery, University of Sherbrooke, Sherbrooke, QC J1H 5N4, Canada; (K.Y.W.)
| | - Gurleen K. Nirwal
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Paul Bélanger
- Division of Ophthalmology, Department of Surgery, University of Sherbrooke, Sherbrooke, QC J1H 5N4, Canada; (K.Y.W.)
| | - Simon D. Tran
- Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC H3A 1G1, Canada
| |
Collapse
|
2
|
Yang H, Zhang H, Li X. Navigating the future of retinitis pigmentosa treatments: A comprehensive analysis of therapeutic approaches in rd10 mice. Neurobiol Dis 2024; 193:106436. [PMID: 38341159 DOI: 10.1016/j.nbd.2024.106436] [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: 12/27/2023] [Revised: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 02/12/2024] Open
Abstract
Retinitis pigmentosa (RP) is a degenerative disease, caused by genetic mutations that lead to a loss in photoreceptors. For research on RP, rd10 mice, which carry mutations in the phosphodiesterase (PDE) gene, exhibit degenerative patterns comparable to those of patients with RP, making them an ideal model for investigating potential treatments. Although numerous studies have reported the potential of biochemical drugs, gene correction, and stem cell transplantation in decelerating rd10 retinal degeneration, a comprehensive review of these studies has yet to be conducted. Therefore, here, a comparative analysis of rd10 mouse treatment research over the past decade was performed. Our findings suggest that biochemical drugs capable of inhibiting the inflammatory response may be promising therapeutics. Additionally, significant progress has been made in the field of gene therapy; nevertheless, challenges such as strict delivery requirements, bystander editing, and off-target effects still need to be resolved. Nevertheless, secretory function is the only unequivocal protective effect of stem cell transplantation. In summary, this review presents a comprehensive analysis and synthesis of the treatment approaches employing rd10 mice as experimental subjects, describing a clear pathway for future RP treatment research and identifies potential clinical interventions.
Collapse
Affiliation(s)
- Hongli Yang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, No. 251, Fukang Road, Tianjin 300384, China.
| | - Hui Zhang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, No. 251, Fukang Road, Tianjin 300384, China
| | - Xiaorong Li
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, No. 251, Fukang Road, Tianjin 300384, China.
| |
Collapse
|
3
|
Wifvat K, Camacho ET, Kawski M, Léveillard T, Wirkus S. Optimal Control with RdCVFL for Degenerating Photoreceptors. Bull Math Biol 2024; 86:29. [PMID: 38345678 PMCID: PMC10861398 DOI: 10.1007/s11538-024-01256-6] [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: 01/03/2023] [Accepted: 01/03/2024] [Indexed: 02/15/2024]
Abstract
Both the rod and cone photoreceptors, along with the retinal pigment epithelium have been experimentally and mathematically shown to work interdependently to maintain vision. Further, the theoredoxin-like rod-derived cone viability factor (RdCVF) and its long form (RdCVFL) have proven to increase photoreceptor survival in experimental results. Aerobic glycolysis is the primary source of energy production for photoreceptors and RdCVF accelerates the intake of glucose into the cones. RdCVFL helps mitigate the negative effects of reactive oxidative species and has shown promise in slowing the death of cones in mouse studies. However, this potential treatment and its effects have never been studied in mathematical models. In this work, we examine an optimal control with the treatment of RdCVFL. We mathematically illustrate the potential this treatment might have for treating degenerative retinal diseases such as retinitis pigmentosa, as well as compare this to the results of an updated control model with RdCVF.
Collapse
Affiliation(s)
- Kathryn Wifvat
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Erika T Camacho
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, 85287, USA
- Department of Mathematics, The University of Texas at San Antonio, San Antonio, TX, 78249, USA
- INSERM, U968, 75012, Paris, France
- UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Sorbonne Universités, 75012, Paris, France
- CNRS, UMR_7210, 75012, Paris, France
| | - Matthias Kawski
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Thierry Léveillard
- INSERM, U968, 75012, Paris, France
- UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Sorbonne Universités, 75012, Paris, France
- CNRS, UMR_7210, 75012, Paris, France
| | - Stephen Wirkus
- Department of Mathematics, The University of Texas at San Antonio, San Antonio, TX, 78249, USA.
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ, 85306, USA.
| |
Collapse
|
4
|
Bighinati A, Adani E, Stanzani A, D’Alessandro S, Marigo V. Molecular mechanisms underlying inherited photoreceptor degeneration as targets for therapeutic intervention. Front Cell Neurosci 2024; 18:1343544. [PMID: 38370034 PMCID: PMC10869517 DOI: 10.3389/fncel.2024.1343544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 01/16/2024] [Indexed: 02/20/2024] Open
Abstract
Retinitis pigmentosa (RP) is a form of retinal degeneration characterized by primary degeneration of rod photoreceptors followed by a secondary cone loss that leads to vision impairment and finally blindness. This is a rare disease with mutations in several genes and high genetic heterogeneity. A challenging effort has been the characterization of the molecular mechanisms underlying photoreceptor cell death during the progression of the disease. Some of the cell death pathways have been identified and comprise stress events found in several neurodegenerative diseases such as oxidative stress, inflammation, calcium imbalance and endoplasmic reticulum stress. Other cell death mechanisms appear more relevant to photoreceptor cells, such as high levels of cGMP and metabolic changes. Here we review some of the cell death pathways characterized in the RP mutant retina and discuss preclinical studies of therapeutic approaches targeting the molecular outcomes that lead to photoreceptor cell demise.
Collapse
Affiliation(s)
- Andrea Bighinati
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Elisa Adani
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Agnese Stanzani
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Sara D’Alessandro
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Valeria Marigo
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Center for Neuroscience and Neurotechnology, Modena, Italy
| |
Collapse
|
5
|
Dobreva A, Camacho ET, Miranda M. Mathematical model for glutathione dynamics in the retina. Sci Rep 2023; 13:10996. [PMID: 37419948 PMCID: PMC10328985 DOI: 10.1038/s41598-023-37938-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 06/29/2023] [Indexed: 07/09/2023] Open
Abstract
The retina is highly susceptible to the generation of toxic reactive oxygen species (ROS) that disrupt the normal operations of retinal cells. The glutathione (GSH) antioxidant system plays an important role in mitigating ROS. To perform its protective functions, GSH depends on nicotinamide adenine dinucleotide phosphate (NADPH) produced through the pentose phosphate pathway. This work develops the first mathematical model for the GSH antioxidant system in the outer retina, capturing the most essential components for formation of ROS, GSH production, its oxidation in detoxifying ROS, and subsequent reduction by NADPH. We calibrate and validate the model using experimental measurements, at different postnatal days up to PN28, from control mice and from the rd1 mouse model for the disease retinitis pigmentosa (RP). Global sensitivity analysis is then applied to examine the model behavior and identify the pathways with the greatest impact in control compared to RP conditions. The findings underscore the importance of GSH and NADPH production in dealing with oxidative stress during retinal development, especially after peak rod degeneration occurs in RP, leading to increased oxygen tension. This suggests that stimulation of GSH and NADPH synthesis could be a potential intervention strategy in degenerative mouse retinas with RP.
Collapse
Affiliation(s)
- Atanaska Dobreva
- Department of Mathematics, Augusta University, Augusta, GA, 30912, USA.
| | - Erika Tatiana Camacho
- University of Texas at San Antonio, San Antonio, TX, 78249, USA
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, 85281, USA
| | - María Miranda
- Department of Biomedical Sciences, Faculty of Health Sciences, Institute of Biomedical Sciences, Cardenal Herrera-CEU University, CEU Universities, 46115, Valencia, Spain
| |
Collapse
|
6
|
Song DJ, Bao XL, Fan B, Li GY. Mechanism of Cone Degeneration in Retinitis Pigmentosa. Cell Mol Neurobiol 2023; 43:1037-1048. [PMID: 35792991 DOI: 10.1007/s10571-022-01243-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 06/13/2022] [Indexed: 11/27/2022]
Abstract
Retinitis pigmentosa (RP) is a group of genetic disorders resulting in inherited blindness due to the degeneration of rod and cone photoreceptors. The various mechanisms underlying rod degeneration primarily rely on genetic mutations, leading to night blindness initially. Cones gradually degenerate after rods are almost eliminated, resulting in varying degrees of visual disability and blindness. The mechanism of cone degeneration remains unclear. An understanding of the mechanisms underlying cone degeneration in RP, a highly heterogeneous disease, is essential to develop novel treatments of RP. Herein, we review recent advancements in the five hypotheses of cone degeneration, including oxidative stress, trophic factors, metabolic stress, light damage, and inflammation activation. We also discuss the connection among these theories to provide a better understanding of secondary cone degeneration in RP. Five current mechanisms of cone degenerations in RP Interactions among different pathways are involved in RP.
Collapse
Affiliation(s)
- De-Juan Song
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China
| | - Xiao-Li Bao
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China
| | - Bin Fan
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China
| | - Guang-Yu Li
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China.
| |
Collapse
|
7
|
Teal CJ, Ho MT, Huo L, Harada H, Bahlmann LC, Léveillard T, Monnier PP, Ramachandran A, Shoichet MS. Affinity-controlled release of rod-derived cone viability factor enhances cone photoreceptor survival. Acta Biomater 2023; 161:37-49. [PMID: 36898472 DOI: 10.1016/j.actbio.2023.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 02/28/2023] [Accepted: 03/02/2023] [Indexed: 03/11/2023]
Abstract
Retinitis pigmentosa (RP) is a group of genetic diseases that results in rod photoreceptor cell degeneration, which subsequently leads to cone photoreceptor cell death, impaired vision and eventual blindness. Rod-derived cone viability factor (RdCVF) is a protein which has two isoforms: a short form (RdCVF) and a long form (RdCVFL) which act on cone photoreceptors in the retina. RdCVFL protects photoreceptors by reducing hyperoxia in the retina; however, sustained delivery of RdCVFL remains challenging. We developed an affinity-controlled release strategy for RdCVFL. An injectable physical blend of hyaluronan and methylcellulose (HAMC) was covalently modified with a peptide binding partner of the Src homology 3 (SH3) domain. This domain was expressed as a fusion protein with RdCVFL, thereby enabling its controlled release from HAMC-binding peptide. Sustained release of RdCVFL was demonstrated for the first time as RdCVFL-SH3 from HAMC-binding peptide for 7 d in vitro. To assess bioactivity, chick retinal dissociates were harvested and treated with the affinity-released recombinant protein from the HAMC-binding peptide vehicle. After 6 d in culture, cone cell viability was greater when cultured with released RdCVFL-SH3 relative to controls. We utilized computational fluid dynamics to model release of RdCVFL-SH3 from our delivery vehicle in the vitreous of the human eye. We demonstrate that our delivery vehicle can prolong the bioavailability of RdCVFL-SH3 in the retina, potentially enhancing its therapeutic effects. Our affinity-based system constitutes a versatile delivery platform for ultimate intraocular injection in the treatment of retinal degenerative diseases. STATEMENT OF SIGNIFICANCE: Retinitis pigmentosa (RP) is the leading cause of inherited blindness in the world. Rod-derived cone viability factor (RdCVF), a novel protein paracrine factor, is effective in preclinical models of RP. To extend its therapeutic effects, we developed an affinity-controlled release strategy for the long form of RdCVF, RdCVFL. We expressed RdCVFL as a fusion protein with an Src homology 3 domain (SH3). We then utilized a hydrogel composed of hyaluronan and methylcellulose (HAMC) and modified it with SH3 binding peptides to investigate its release in vitro. Furthermore, we designed a mathematical model of the human eye to investigate delivery of the protein from the delivery vehicle. This work paves the way for future investigation of controlled release RdCVF.
Collapse
Affiliation(s)
- Carter J Teal
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, M5S 3G9 Toronto, Ontario, Canada; Donnelly Centre, University of Toronto, 160 College Street, M5S3E1 Toronto, Ontario, Canada
| | - Margaret T Ho
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, M5S 3G9 Toronto, Ontario, Canada; Donnelly Centre, University of Toronto, 160 College Street, M5S3E1 Toronto, Ontario, Canada
| | - Lia Huo
- Donnelly Centre, University of Toronto, 160 College Street, M5S3E1 Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, 1 King's College Circle, M5S 1A8 Toronto, Ontario, Canada
| | - Hidekiyo Harada
- Donald K. Johnson Research Institute, Krembil Research Institute, Krembil Discovery Tower, Toronto, Ontario, Canada
| | - Laura C Bahlmann
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, M5S 3G9 Toronto, Ontario, Canada; Donnelly Centre, University of Toronto, 160 College Street, M5S3E1 Toronto, Ontario, Canada
| | - Thierry Léveillard
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France
| | - Philippe P Monnier
- Donald K. Johnson Research Institute, Krembil Research Institute, Krembil Discovery Tower, Toronto, Ontario, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Arun Ramachandran
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, M5S 3E5 Toronto, Ontario, Canada
| | - Molly S Shoichet
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, M5S 3G9 Toronto, Ontario, Canada; Donnelly Centre, University of Toronto, 160 College Street, M5S3E1 Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, 1 King's College Circle, M5S 1A8 Toronto, Ontario, Canada; Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, M5S 3E5 Toronto, Ontario, Canada; Department of Chemistry, University of Toronto, 80 Saint George Street, M5S 3H6 Toronto, Ontario, Canada.
| |
Collapse
|
8
|
Polyunsaturated Lipids in the Light-Exposed and Prooxidant Retinal Environment. Antioxidants (Basel) 2023; 12:antiox12030617. [PMID: 36978865 PMCID: PMC10044808 DOI: 10.3390/antiox12030617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/26/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023] Open
Abstract
The retina is an oxidative stress-prone tissue due to high content of polyunsaturated lipids, exposure to visible light stimuli in the 400–480 nm range, and high oxygen availability provided by choroidal capillaries to support oxidative metabolism. Indeed, lipids’ peroxidation and their conversion into reactive species promoting inflammation have been reported and connected to retinal degenerations. Here, we review recent evidence showing how retinal polyunsaturated lipids, in addition to oxidative stress and damage, may counteract the inflammatory response triggered by blue light-activated carotenoid derivatives, enabling long-term retina operation despite its prooxidant environment. These two aspects of retinal polyunsaturated lipids require tight control over their synthesis to avoid overcoming their protective actions by an increase in lipid peroxidation due to oxidative stress. We review emerging evidence on different transcriptional control mechanisms operating in retinal cells to modulate polyunsaturated lipid synthesis over the life span, from the immature to the ageing retina. Finally, we discuss the antioxidant role of food nutrients such as xanthophylls and carotenoids that have been shown to empower retinal cells’ antioxidant responses and counteract the adverse impact of prooxidant stimuli on sight.
Collapse
|
9
|
Ren X, Léveillard T. Modulating antioxidant systems as a therapeutic approach to retinal degeneration. Redox Biol 2022; 57:102510. [PMID: 36274523 PMCID: PMC9596747 DOI: 10.1016/j.redox.2022.102510] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/11/2022] [Accepted: 10/11/2022] [Indexed: 11/21/2022] Open
Abstract
The human retina is facing a big challenge of reactive oxygen species (ROS) from endogenous and exogenous sources. Excessive ROS can cause damage to DNA, lipids, and proteins, triggering abnormal redox signaling, and ultimately lead to cell death. Thus, oxidative stress has been observed in inherited retinal diseases as a common hallmark. To counteract the detrimental effect of ROS, cells are equipped with various antioxidant defenses. In this review, we will focus on the antioxidant systems in the retina and how they can protect retina from oxidative stress. Both small antioxidants and antioxidant enzymes play a role in ROS removal. Particularly, the thioredoxin and glutaredoxin systems, as the major antioxidant systems in mammalian cells, exert functions in redox signaling regulation via modifying cysteines in proteins. In addition, the thioredoxin-like rod-derived cone viability factor (RdCVFL) and thioredoxin interacting protein (TXNIP) can modulate metabolism in photoreceptors and promote their survival. In conclusion, elevating the antioxidant capacity in retina is a promising therapy to curb the progress of inherited retinal degeneration.
Collapse
Affiliation(s)
- Xiaoyuan Ren
- Department of Genetics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France; Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17177, Sweden.
| | - Thierry Léveillard
- Department of Genetics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France.
| |
Collapse
|
10
|
Aït-Ali N, Léveillard T. The Emergence of Rod-Cone Cellular Interaction. Front Genet 2022; 13:900849. [PMID: 36017494 PMCID: PMC9396122 DOI: 10.3389/fgene.2022.900849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 06/17/2022] [Indexed: 11/25/2022] Open
Abstract
We studied the origin of rod-derived cone viability factor (RdCVF) during evolution. In mammals, the nucleoredoxin-like 1 gene (NXNL1) produces a truncated thioredoxin-like protein, RdCVF, by intron retention in rod photoreceptors of the retina. This protein prevents the secondary cone degeneration in animal models of rod-cone degeneration. Extracellular RdCVF binds to a complex at the surface of the cones, composed of the basigin-1, a photoreceptor specific alternative splicing product of the basigin gene, and GLUT1, the glucose transporter. RdCVF accelerates glucose uptake allosterically. Glucose is either metabolized by aerobic glycolysis to sustain cone outer segment renewal or by the pentose phosphate pathway to support redox power to the thioredoxin RdCVFL. RdCVF signaling predates the appearance of the eye and evolved through two alternative splicing events. RdCVF signaling is observed first in hydra where it regulates an unknown signaling. A scallop RdCVF protein is produced by ciliated photoreceptors of the retina and binds its receptor, BSG1, the first occurrence of RdCVF/BSG1 signaling. In the lamprey, RdCVF metabolic signaling between rod and cones is fully operational. In the mouse, the production of BSG1 is regulated through alternative splicing. This signaling was extended to other regions of the brain, via its paralogue NXNL2.
Collapse
|
11
|
Roberts PA. Inverse Problem Reveals Conditions for Characteristic Retinal Degeneration Patterns in Retinitis Pigmentosa Under the Trophic Factor Hypothesis. Front Aging Neurosci 2022; 14:765966. [PMID: 35585866 PMCID: PMC9108254 DOI: 10.3389/fnagi.2022.765966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 03/21/2022] [Indexed: 12/05/2022] Open
Abstract
Retinitis pigmentosa (RP) is the most common inherited retinal dystrophy with a prevalence of about 1 in 4,000, affecting approximately 1.5 million people worldwide. Patients with RP experience progressive visual field loss as the retina degenerates, destroying light-sensitive photoreceptor cells (rods and cones), with rods affected earlier and more severely than cones. Spatio-temporal patterns of retinal degeneration in human RP have been well characterised; however, the mechanism(s) giving rise to these patterns have not been conclusively determined. One such mechanism, which has received a wealth of experimental support, is described by the trophic factor hypothesis. This hypothesis suggests that rods produce a trophic factor necessary for cone survival; the loss of rods depletes this factor, leading to cone degeneration. In this article, we formulate a partial differential equation mathematical model of RP in one spatial dimension, spanning the region between the retinal centre (fovea) and the retinal edge (ora serrata). Using this model we derive and solve an inverse problem, revealing for the first time experimentally testable conditions under which the trophic factor mechanism will qualitatively recapitulate the spatio-temporal patterns of retinal regeneration observed in human RP.
Collapse
|
12
|
Idelfonso-García OG, Alarcón-Sánchez BR, Vásquez-Garzón VR, Baltiérrez-Hoyos R, Villa-Treviño S, Muriel P, Serrano H, Pérez-Carreón JI, Arellanes-Robledo J. Is Nucleoredoxin a Master Regulator of Cellular Redox Homeostasis? Its Implication in Different Pathologies. Antioxidants (Basel) 2022; 11:antiox11040670. [PMID: 35453355 PMCID: PMC9030443 DOI: 10.3390/antiox11040670] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/26/2022] [Accepted: 03/28/2022] [Indexed: 01/27/2023] Open
Abstract
Nucleoredoxin (NXN), an oxidoreductase enzyme, contributes to cellular redox homeostasis by regulating different signaling pathways in a redox-dependent manner. By interacting with seven proteins so far, namely disheveled (DVL), protein phosphatase 2A (PP2A), phosphofructokinase-1 (PFK1), translocation protein SEC63 homolog (SEC63), myeloid differentiation primary response gene-88 (MYD88), flightless-I (FLII), and calcium/calmodulin-dependent protein kinase II type alpha (CAMK2A), NXN is involved in the regulation of several key cellular processes, including proliferation, organogenesis, cell cycle progression, glycolysis, innate immunity and inflammation, motility, contraction, protein transport into the endoplasmic reticulum, neuronal plasticity, among others; as a result, NXN has been implicated in different pathologies, such as cancer, alcoholic and polycystic liver disease, liver fibrogenesis, obesity, Robinow syndrome, diabetes mellitus, Alzheimer’s disease, and retinitis pigmentosa. Together, this evidence places NXN as a strong candidate to be a master redox regulator of cell physiology and as the hub of different redox-sensitive signaling pathways and associated pathologies. This review summarizes and discusses the current insights on NXN-dependent redox regulation and its implication in different pathologies.
Collapse
Affiliation(s)
- Osiris Germán Idelfonso-García
- Laboratory of Liver Diseases, National Institute of Genomic Medicine–INMEGEN, Mexico City 14610, Mexico; (O.G.I.-G.); (B.R.A.-S.); (J.I.P.-C.)
- Department of Health Sciences, Metropolitan Autonomous University-Iztapalapa Campus, Mexico City 09340, Mexico;
| | - Brisa Rodope Alarcón-Sánchez
- Laboratory of Liver Diseases, National Institute of Genomic Medicine–INMEGEN, Mexico City 14610, Mexico; (O.G.I.-G.); (B.R.A.-S.); (J.I.P.-C.)
- Department of Cell Biology, Center for Research and Advanced Studies of the National Polytechnic Institute–CINVESTAV-IPN, Mexico City 07360, Mexico;
| | - Verónica Rocío Vásquez-Garzón
- Laboratory of Fibrosis and Cancer, Faculty of Medicine and Surgery, ‘Benito Juárez’ Autonomous University of Oaxaca–UABJO, Oaxaca 68020, Mexico; (V.R.V.-G.); (R.B.-H.)
- Directorate of Cátedras, National Council of Science and Technology–CONACYT, Mexico City 03940, Mexico
| | - Rafael Baltiérrez-Hoyos
- Laboratory of Fibrosis and Cancer, Faculty of Medicine and Surgery, ‘Benito Juárez’ Autonomous University of Oaxaca–UABJO, Oaxaca 68020, Mexico; (V.R.V.-G.); (R.B.-H.)
- Directorate of Cátedras, National Council of Science and Technology–CONACYT, Mexico City 03940, Mexico
| | - Saúl Villa-Treviño
- Department of Cell Biology, Center for Research and Advanced Studies of the National Polytechnic Institute–CINVESTAV-IPN, Mexico City 07360, Mexico;
| | - Pablo Muriel
- Laboratory of Experimental Hepatology, Department of Pharmacology, Center for Research and Advanced Studies of the National Polytechnic Institute–CINVESTAV-IPN, Mexico City 07360, Mexico;
| | - Héctor Serrano
- Department of Health Sciences, Metropolitan Autonomous University-Iztapalapa Campus, Mexico City 09340, Mexico;
| | - Julio Isael Pérez-Carreón
- Laboratory of Liver Diseases, National Institute of Genomic Medicine–INMEGEN, Mexico City 14610, Mexico; (O.G.I.-G.); (B.R.A.-S.); (J.I.P.-C.)
| | - Jaime Arellanes-Robledo
- Laboratory of Liver Diseases, National Institute of Genomic Medicine–INMEGEN, Mexico City 14610, Mexico; (O.G.I.-G.); (B.R.A.-S.); (J.I.P.-C.)
- Directorate of Cátedras, National Council of Science and Technology–CONACYT, Mexico City 03940, Mexico
- Correspondence: ; Tel.: +52-55-5350-1900 (ext. 1218)
| |
Collapse
|
13
|
Jaillard C, Ouechtati F, Clérin E, Millet-Puel G, Corsi M, Aït-Ali N, Blond F, Chevy Q, Gales L, Farinelli M, Dalkara D, Sahel JA, Portais JC, Poncer JC, Léveillard T. The metabolic signaling of the nucleoredoxin-like 2 gene supports brain function. Redox Biol 2021; 48:102198. [PMID: 34856436 PMCID: PMC8640531 DOI: 10.1016/j.redox.2021.102198] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 11/22/2021] [Indexed: 01/04/2023] Open
Abstract
The nucleoredoxin gene NXNL2 encodes for two products through alternative splicing, rod-derived cone viability factor-2 (RdCVF2) that mediates neuronal survival and the thioredoxin-related protein (RdCVF2L), an enzyme that regulates the phosphorylation of TAU. To investigate the link between NXNL2 and tauopathies, we studied the Nxnl2 knockout mouse (Nxnl2-/-). We established the expression pattern of the Nxnl2 gene in the brain using a Nxnl2 reporter mouse line, and characterized the behavior of the Nxnl2-/- mouse at 2 months of age. Additionally, long term potentiation and metabolomic from hippocampal specimens were collected at 2 months of age. We studied TAU oligomerization, phosphorylation and aggregation in Nxnl2-/- brain at 18 months of age. Finally, newborn Nxnl2-/- mice were treated with adeno-associated viral vectors encoding for RdCVF2, RdCVF2L or both and measured the effect of this therapy on long-term potential, glucose metabolism and late-onset tauopathy. Nxnl2-/- mice at 2 months of age showed severe behavioral deficiency in fear, pain sensitivity, coordination, learning and memory. The Nxnl2-/- also showed deficits in long-term potentiation, demonstrating that the Nxnl2 gene is involved in regulating brain functions. Dual delivery of RdCVF2 and RdCVF2L in newborn Nxnl2-/- mice fully correct long-term potentiation through their synergistic action. The expression pattern of the Nxnl2 gene in the brain shows a predominant expression in circumventricular organs, such as the area postrema. Glucose metabolism of the hippocampus of Nxnl2-/- mice at 2 months of age was reduced, and was not corrected by gene therapy. At 18-month-old Nxnl2-/- mice showed brain stigmas of tauopathy, such as oligomerization, phosphorylation and aggregation of TAU. This late-onset tauopathy can be prevented, albeit with modest efficacy, by recombinant AAVs administrated to newborn mice. The Nxnl2-/- mice have memory dysfunction at 2-months that resembles mild-cognitive impairment and at 18-months exhibit tauopathy, resembling to the progression of Alzheimer's disease. We propose the Nxnl2-/- mouse is a model to study multistage aged related neurodegenerative diseases. The NXNL2 metabolic and redox signaling is a new area of therapeutic research in neurodegenerative diseases.
Collapse
Affiliation(s)
- Céline Jaillard
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-7501b, Paris, France
| | - Farah Ouechtati
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-7501b, Paris, France
| | - Emmanuelle Clérin
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-7501b, Paris, France
| | | | - Mariangela Corsi
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-7501b, Paris, France
| | - Najate Aït-Ali
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-7501b, Paris, France
| | - Frédéric Blond
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-7501b, Paris, France
| | - Quentin Chevy
- Sorbonne Université, INSERM, CNRS, Institut du Fer à Moulin, F-75005, Paris, France
| | - Lara Gales
- MetaToul-MetaboHUB, National Infrastructure of Metabolomics & Fluxomics, 31077, Toulouse, France
| | - Mélissa Farinelli
- E-Phy-Science, Bioparc de Sophia Antipolis, 2400 route des Colles, 06410, Biot, France
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-7501b, Paris, France
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-7501b, Paris, France
| | - Jean-Charles Portais
- MetaToul-MetaboHUB, National Infrastructure of Metabolomics & Fluxomics, 31077, Toulouse, France
| | | | - Thierry Léveillard
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-7501b, Paris, France.
| |
Collapse
|
14
|
Roberts PA. Mathematical Models of Retinitis Pigmentosa: The Trophic Factor Hypothesis. J Theor Biol 2021; 534:110938. [PMID: 34687673 DOI: 10.1016/j.jtbi.2021.110938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 10/02/2021] [Accepted: 10/04/2021] [Indexed: 10/20/2022]
Abstract
Retinitis pigmentosa (RP) is the term used to denote a group of inherited retinal-degenerative conditions that cause progressive sight loss. Individuals with this condition lose their light-sensitive photoreceptor cells, known as rods and cones, over a period of years to decades; degeneration starting in the retinal periphery, and spreading peripherally and centrally over time. RP is a rod-cone dystrophy, meaning that rod health and function are affected earlier and more severely than that of cones. Rods degenerate due to an underlying mutation, whereas the reasons for cone degeneration are unknown. A number of mechanisms have been proposed to explain secondary cone loss and the spatio-temporal patterns of retinal degeneration in RP. One of the most promising is the trophic factor hypothesis, which suggests that rods produce a factor necessary for cone survival, such that, when rods degenerate, cone degeneration follows. In this paper we formulate and analyse mathematical models of human RP under the trophic factor hypothesis. These models are constructed as systems of reaction-diffusion partial differential equations in one spatial dimension, and are solved and analysed using a combination of numerical and analytical methods. We predict the conditions under which cones will degenerate following the loss of a patch of rods from the retina, the critical trophic factor treatment rate required to prevent cone degeneration following rod loss and the spatio-temporal patterns of cone loss that would result if the trophic factor mechanism alone were responsible for retinal degeneration.
Collapse
Affiliation(s)
- Paul A Roberts
- School of Life Sciences, University of Sussex, John Maynard Smith Building, Brighton BN1 9QG, UK.
| |
Collapse
|
15
|
Assessing Photoreceptor Status in Retinal Dystrophies: From High-Resolution Imaging to Functional Vision. Am J Ophthalmol 2021; 230:12-47. [PMID: 34000280 PMCID: PMC8682761 DOI: 10.1016/j.ajo.2021.04.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 04/15/2021] [Accepted: 04/15/2021] [Indexed: 01/05/2023]
Abstract
Purpose To describe the value of integrating phenotype/genotype data, disease staging, and evaluation of functional vision in patient-centered management of retinal dystrophies. Methods (1) Cross-sectional structure-function and retrospective longitudinal studies to assess the correlations between standard fundus autofluorescence (FAF), optical coherence tomography, visual acuity (VA), and perimetry (visual field [VF]) examinations to evaluate photoreceptor functional loss in a cohort of patients with rod-cone dystrophy (RCD); (2) flood-illumination adaptive optics (FIAO) imaging focusing on photoreceptor misalignment and orientation of outer segments; and (3) evaluation of the impact of visual impairment in daily life activities, based on functional (visual and mobility) vision assessment in a naturalistic environment in visually impaired subjects with RCD and subjects treated with LuxturnaⓇ for RPE65-related Leber congenital amaurosis before and after therapy. Results The results of the cross-sectional transversal study showed that (1) VA and macular sensitivity were weakly correlated with the structural variables; and (2) functional impairment (VF) was correlated with reduction of anatomical markers of photoreceptor structure and increased width of autofluorescent ring. The dimensions of the ring of increased FAF evolved faster. Other criteria that differed among groups were the lengths of the ellipsoid zone, the external limiting membrane, and the foveal thickness. FIAO revealed a variety of phenotypes: paradoxical visibility of foveal cones; heterogeneous brightness of cones; dim, inner segment–like, and RPE-like mosaic. Directional illumination by varying orientation of incident light (Stiles-Crawford effect) and the amount of side illumination (gaze-dependent imaging) affected photoreceptor visibility. Mobility assessment under different lighting conditions showed correlation with VF, VA, contrast sensitivity (CS), and dark adaptation, with different predictive values depending on mobility study paradigms and illumination level. At high illumination level (235 lux), VF was a predictor for all mobility performance models. Under low illumination (1 and 2 lux), VF was the most significant predictor of mobility performance variables, while CS best explained the number of collisions and segments. In subjects treated with LuxturnaⓇ, a very favorable impact on travel speed and reduction in the number of collisions, especially at low luminance, was observable 6 months following injection, in both children and adults. Conclusions Our results suggest the benefit of development and implementation of quantitative and reproducible tools to evaluate the status of photoreceptors and the impact of both visual impairment and novel therapies in real-life conditions. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.
Collapse
|
16
|
Andreazzoli M, Barravecchia I, De Cesari C, Angeloni D, Demontis GC. Inducible Pluripotent Stem Cells to Model and Treat Inherited Degenerative Diseases of the Outer Retina: 3D-Organoids Limitations and Bioengineering Solutions. Cells 2021; 10:cells10092489. [PMID: 34572137 PMCID: PMC8471616 DOI: 10.3390/cells10092489] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/12/2021] [Accepted: 09/15/2021] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal degenerations (IRD) affecting either photoreceptors or pigment epithelial cells cause progressive visual loss and severe disability, up to complete blindness. Retinal organoids (ROs) technologies opened up the development of human inducible pluripotent stem cells (hiPSC) for disease modeling and replacement therapies. However, hiPSC-derived ROs applications to IRD presently display limited maturation and functionality, with most photoreceptors lacking well-developed outer segments (OS) and light responsiveness comparable to their adult retinal counterparts. In this review, we address for the first time the microenvironment where OS mature, i.e., the subretinal space (SRS), and discuss SRS role in photoreceptors metabolic reprogramming required for OS generation. We also address bioengineering issues to improve culture systems proficiency to promote OS maturation in hiPSC-derived ROs. This issue is crucial, as satisfying the demanding metabolic needs of photoreceptors may unleash hiPSC-derived ROs full potential for disease modeling, drug development, and replacement therapies.
Collapse
Affiliation(s)
| | - Ivana Barravecchia
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy;
- Institute of Life Sciences, Scuola Superiore Sant’Anna, 56124 Pisa, Italy;
| | | | - Debora Angeloni
- Institute of Life Sciences, Scuola Superiore Sant’Anna, 56124 Pisa, Italy;
| | - Gian Carlo Demontis
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy;
- Correspondence: (M.A.); (G.C.D.)
| |
Collapse
|
17
|
Sahu B, Leon LM, Zhang W, Puranik N, Periasamy R, Khanna H, Volkert M. Oxidative Stress Resistance 1 Gene Therapy Retards Neurodegeneration in the rd1 Mutant Mouse Model of Retinopathy. Invest Ophthalmol Vis Sci 2021; 62:8. [PMID: 34505865 PMCID: PMC8434758 DOI: 10.1167/iovs.62.12.8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/19/2021] [Indexed: 12/17/2022] Open
Abstract
Purpose Oxidative stress is a major factor underlying many neurodegenerative diseases. However, antioxidant therapy has had mixed results, possibly because of its indiscriminate activity. The purpose of our study was to determine if the human OXR1 (hOXR1) antioxidant regulatory gene could protect neurons from oxidative stress and delay photoreceptor cell death. Methods The cone-like 661W cell line was transfected to stably express the hOXR1 gene. Oxidative stress was induced by the addition of hydrogen peroxide (H2O2). Intracellular levels of reactive oxygen species (ROS), caspase cleavage, and cellular resistance to oxidative stress were determined and compared between the control and hOXR1 cells. For in vivo analysis, AAV8-hOXR1 was injected subretinally into the rd1 mouse model of retinal degeneration. Functional and structural integrity of the photoreceptors were assessed using electroretinography (ERG), histology, and immunofluorescence analysis. Results Expression of hOXR1 increased cellular resistance and reduced ROS levels and caspase cleavage in the 661W cell line after H2O2-induced oxidative stress. Subretinal injection of AAV8-hOXR1 in the rd1 mice improved their photoreceptor light response, expression and localization of photoreceptor-specific proteins, and delayed retinal degeneration. Conclusions Our results suggest that OXR1 is a potential therapy candidate for retinal degeneration. Because OXR1 targets oxidative stress, a common feature of many retinal degenerative diseases, it should be of therapeutic value to multiple retinal degenerative diseases.
Collapse
Affiliation(s)
- Bhubanananda Sahu
- Department of Ophthalmology and Visual Science, University of Massachusetts Medical School, Worcester, Massachusetts, United States
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Laura Moreno Leon
- Department of Ophthalmology and Visual Science, University of Massachusetts Medical School, Worcester, Massachusetts, United States
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Wei Zhang
- Department of Ophthalmology and Visual Science, University of Massachusetts Medical School, Worcester, Massachusetts, United States
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Nikita Puranik
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Ramesh Periasamy
- Department of Ophthalmology and Visual Science, University of Massachusetts Medical School, Worcester, Massachusetts, United States
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Hemant Khanna
- Department of Ophthalmology and Visual Science, University of Massachusetts Medical School, Worcester, Massachusetts, United States
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, United States
- NeuroNexus Institute, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Michael Volkert
- NeuroNexus Institute, University of Massachusetts Medical School, Worcester, Massachusetts, United States
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| |
Collapse
|
18
|
Botto C, Rucli M, Tekinsoy MD, Pulman J, Sahel JA, Dalkara D. Early and late stage gene therapy interventions for inherited retinal degenerations. Prog Retin Eye Res 2021; 86:100975. [PMID: 34058340 DOI: 10.1016/j.preteyeres.2021.100975] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/18/2021] [Accepted: 05/21/2021] [Indexed: 12/12/2022]
Abstract
Inherited and age-related retinal degeneration is the hallmark of a large group of heterogeneous diseases and is the main cause of untreatable blindness today. Genetic factors play a major pathogenic role in retinal degenerations for both monogenic diseases (such as retinitis pigmentosa) and complex diseases with established genetic risk factors (such as age-related macular degeneration). Progress in genotyping techniques and back of the eye imaging are completing our understanding of these diseases and their manifestations in patient populations suffering from retinal degenerations. It is clear that whatever the genetic cause, the majority of vision loss in retinal diseases results from the loss of photoreceptor function. The timing and circumstances surrounding the loss of photoreceptor function determine the adequate therapeutic approach to use for each patient. Among such approaches, gene therapy is rapidly becoming a therapeutic reality applicable in the clinic. This massive move from laboratory work towards clinical application has been propelled by the advances in our understanding of disease genetics and mechanisms, gene delivery vectors, gene editing systems, and compensatory strategies for loss of photoreceptor function. Here, we provide an overview of existing modalities of retinal gene therapy and their relevance based on the needs of patient populations suffering from inherited retinal degenerations.
Collapse
Affiliation(s)
- Catherine Botto
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Marco Rucli
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Müge Defne Tekinsoy
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Juliette Pulman
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France; Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, United States; CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, F-75012, Paris, France; Fondation Ophtalmologique Rothschild, F-75019, Paris, France
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France.
| |
Collapse
|
19
|
Wifvat K, Camacho ET, Wirkus S, Léveillard T. The role of RdCVFL in a mathematical model of photoreceptor interactions. J Theor Biol 2021; 520:110642. [PMID: 33636201 DOI: 10.1016/j.jtbi.2021.110642] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/08/2021] [Accepted: 02/11/2021] [Indexed: 01/16/2023]
Abstract
Recent experimental and mathematical work has shown the interdependence of the rod and cone photoreceptors with the retinal pigment epithelium in maintaining sight. Accelerated intake of glucose into the cones via the theoredoxin-like rod-derived cone viability factor (RdCVF) is needed as aerobic glycolysis is the primary source of energy production. Reactive oxidative species (ROS) result from the rod and cone metabolism and recent experimental work has shown that the long form of RdCVF (RdCVFL) helps mitigate the negative effects of ROS. In this work we investigate the role of RdCVFL in maintaining the health of the photoreceptors. The results of our mathematical model show the necessity of RdCVFL and also demonstrate additional stable modes that are present in this system. The sensitivity analysis shows the importance of glucose uptake, nutrient levels, and ROS mitigation in maintaining rod and cone health in light-damaged mouse models. Together, these suggests areas on which to focus treatment in order to prolong the photoreceptors, especially in situations where ROS is a contributing factor to their death such as retinitis pigmentosa.
Collapse
Affiliation(s)
- Kathryn Wifvat
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, United States
| | - Erika T Camacho
- School of Mathematical & Natural Sciences, Arizona State University, Glendale, AZ 85306, United States
| | - Stephen Wirkus
- School of Mathematical & Natural Sciences, Arizona State University, Glendale, AZ 85306, United States
| | - Thierry Léveillard
- INSERM, U968, Paris F-75012, France; Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris F-75012, France; CNRS, UMR_7210, Paris F-75012, France
| |
Collapse
|
20
|
Hydrogel-mediated co-transplantation of retinal pigmented epithelium and photoreceptors restores vision in an animal model of advanced retinal degeneration. Biomaterials 2020; 257:120233. [DOI: 10.1016/j.biomaterials.2020.120233] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 07/07/2020] [Accepted: 07/10/2020] [Indexed: 01/01/2023]
|
21
|
Di Pierdomenico J, Martínez-Vacas A, Hernández-Muñoz D, Gómez-Ramírez AM, Valiente-Soriano FJ, Agudo-Barriuso M, Vidal-Sanz M, Villegas-Pérez MP, García-Ayuso D. Coordinated Intervention of Microglial and Müller Cells in Light-Induced Retinal Degeneration. Invest Ophthalmol Vis Sci 2020; 61:47. [PMID: 32232352 PMCID: PMC7401701 DOI: 10.1167/iovs.61.3.47] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Purpose To analyze the role of microglial and Müller cells in the formation of rings of photoreceptor degeneration caused by phototoxicity. Methods Two-month-old Sprague-Dawley rats were exposed to light and processed 1, 2, or 3 months later. Retinas were dissected as whole-mounts, immunodetected for microglial cells, Müller cells, and S- and L/M-cones and analyzed using fluorescence, thunder imaging, and confocal microscopy. Cone populations were automatically counted and isodensity maps constructed to document cone topography. Results Phototoxicity causes a significant progressive loss of S- and L/M-cones of up to 68% and 44%, respectively, at 3 months after light exposure (ALE). One month ALE, we observed rings of cone degeneration in the photosensitive area of the superior retina. Two and 3 months ALE, these rings had extended to the central and inferior retina. Within the rings of cone degeneration, there were degenerating cones, often activated microglial cells, and numerous radially oriented processes of Müller cells that showed increased expression of intermediate filaments. Between 1 and 3 months ALE, the rings coalesced, and at the same time the microglial cells resumed a mosaic-like distribution, and there was a decrease of Müller cell gliosis at the areas devoid of cones. Conclusions Light-induced photoreceptor degeneration proceeds with rings of cone degeneration, as observed in inherited retinal degenerations in which cone death is secondary to rod degeneration. The spatiotemporal relationship of cone death microglial cell activation and Müller cell gliosis within the rings of cone degeneration suggests that, although both glial cells are involved in the formation of the rings, they may have coordinated actions and, while microglial cells may be more involved in photoreceptor phagocytosis, Müller cells may be more involved in cone and microglial cell migration, retinal remodeling and glial seal formation.
Collapse
|
22
|
Metabolic and Redox Signaling of the Nucleoredoxin-Like-1 Gene for the Treatment of Genetic Retinal Diseases. Int J Mol Sci 2020; 21:ijms21051625. [PMID: 32120883 PMCID: PMC7084304 DOI: 10.3390/ijms21051625] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 02/06/2023] Open
Abstract
The loss of cone photoreceptor function in retinitis pigmentosa (RP) severely impacts the central and daily vision and quality of life of patients affected by this disease. The loss of cones follows the degeneration of rods, in a manner independent of the causing mutations in numerous genes associated with RP. We have explored this phenomenon and proposed that the loss of rods triggers a reduction in the expression of rod-derived cone viability factor (RdCVF) encoded by the nucleoredoxin-like 1 (NXNL1) gene which interrupts the metabolic and redox signaling between rods and cones. After providing scientific evidence supporting this mechanism, we propose a way to restore this lost signaling and prevent the cone vision loss in animal models of RP. We also explain how we could restore this signaling to prevent cone vision loss in animal models of the disease and how we plan to apply this therapeutic strategy by the administration of both products of NXNL1 encoding the trophic factor RdCVF and the thioredoxin enzyme RdCVFL using an adeno-associated viral vector. We describe in detail all the steps of this translational program, from the design of the drug, its production, biological validation, and analytical and preclinical qualification required for a future clinical trial that would, if successful, provide a treatment for this incurable disease.
Collapse
|
23
|
Holubiec MI, Galeano P, Romero JI, Hanschmann EM, Lillig CH, Capani F. Thioredoxin 1 Plays a Protective Role in Retinas Exposed to Perinatal Hypoxia-Ischemia. Neuroscience 2019; 425:235-250. [PMID: 31785355 DOI: 10.1016/j.neuroscience.2019.11.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 11/07/2019] [Accepted: 11/08/2019] [Indexed: 12/20/2022]
Abstract
Thioredoxin family proteins are key modulators of cellular redox regulation and have been linked to several physiological functions, including the cellular response to hypoxia-ischemia. During perinatal hypoxia-ischemia (PHI), the central nervous system is subjected to a fast decrease in O2 and nutrients with a subsequent reoxygenation that ultimately leads to the production of reactive species impairing physiological redox signaling. Particularly, the retina is one of the most affected tissues, due to its high oxygen consumption and exposure to light. One of the main consequences of PHI is retinopathy of prematurity, comprising changes in retinal neural and vascular development, with further compensatory mechanisms that can ultimately lead to retinal detachment and blindness. In this study, we have analyzed long-term changes that occur in the retina using two well established in vivo rat PHI models (perinatal asphyxia and carotid ligation model), as well as the ARPE-19 cell line that was exposed to hypoxia and reoxygenation. We observed significant changes in the protein levels of the cytosolic oxidoreductase thioredoxin 1 (Trx1) in both animal models and a cell model. Knock-down of Trx1 in ARPE-19 cells affected cell morphology, proliferation and the levels of specific differentiation markers. Administration of recombinant Trx1 decreased astrogliosis and improved delayed neurodevelopment in animals exposed to PHI. Taken together, our results suggest therapeutical implications for Trx1 in retinal damage induced by hypoxia-ischemia during birth.
Collapse
Affiliation(s)
- M I Holubiec
- Laboratorio de Citoarquitectura y Plasticidad Neuronal, Instituto de Investigaciones Cardiológicas "Prof. Dr. Alberto C. Taquini" (ININCA), Facultad de Medicina (UBA-CONICET), Buenos Aires, Argentina; Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Argentina.
| | - P Galeano
- Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Argentina
| | - J I Romero
- Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Argentina
| | - E-M Hanschmann
- Department of Neurology, Heinrich-Heine University Düsseldorf, Germany; Institute for Medical Biochemistry and Molecular Biology, University of Greifswald, Germany
| | - C H Lillig
- Institute for Medical Biochemistry and Molecular Biology, University of Greifswald, Germany
| | - F Capani
- Laboratorio de Citoarquitectura y Plasticidad Neuronal, Instituto de Investigaciones Cardiológicas "Prof. Dr. Alberto C. Taquini" (ININCA), Facultad de Medicina (UBA-CONICET), Buenos Aires, Argentina; Facultad de Medicina, Universidad Católica Argentina (UCA), Buenos Aires, Argentina; Universidad Autónoma de Chile, Santiago de Chile, Chile
| |
Collapse
|
24
|
A Mathematical Analysis of Aerobic Glycolysis Triggered by Glucose Uptake in Cones. Sci Rep 2019; 9:4162. [PMID: 30858444 PMCID: PMC6411757 DOI: 10.1038/s41598-019-39901-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 01/31/2019] [Indexed: 11/08/2022] Open
Abstract
Patients affected by retinitis pigmentosa, an inherited retinal disease, experience a decline in vision due to photoreceptor degeneration leading to irreversible blindness. Rod-derived cone viability factor (RdCVF) is the most promising mutation-independent treatment today. To identify pathologic processes leading to secondary cone photoreceptor dysfunction triggering central vision loss of these patients, we model the stimulation by RdCVF of glucose uptake in cones and glucose metabolism by aerobic glycolysis. We develop a nonlinear system of enzymatic functions and differential equations to mathematically model molecular and cellular interactions in a cone. We use uncertainty and sensitivity analysis to identify processes that have the largest effect on the system and their timeframes. We consider the case of a healthy cone, a cone with low levels of glucose, and a cone with low and no RdCVF. The three key processes identified are metabolism of fructose-1,6-bisphosphate, production of glycerol-3-phosphate and competition that rods exert on cone resources. The first two processes are proportional to the partition of the carbon flux between glycolysis and the pentose phosphate pathway or the Kennedy pathway, respectively. The last process is the rods' competition for glucose, which may explain why rods also provide the RdCVF signal to compensate.
Collapse
|
25
|
Léveillard T, Philp NJ, Sennlaub F. Is Retinal Metabolic Dysfunction at the Center of the Pathogenesis of Age-related Macular Degeneration? Int J Mol Sci 2019; 20:ijms20030762. [PMID: 30754662 PMCID: PMC6387069 DOI: 10.3390/ijms20030762] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/04/2019] [Accepted: 02/05/2019] [Indexed: 01/12/2023] Open
Abstract
The retinal pigment epithelium (RPE) forms the outer blood⁻retina barrier and facilitates the transepithelial transport of glucose into the outer retina via GLUT1. Glucose is metabolized in photoreceptors via the tricarboxylic acid cycle (TCA) and oxidative phosphorylation (OXPHOS) but also by aerobic glycolysis to generate glycerol for the synthesis of phospholipids for the renewal of their outer segments. Aerobic glycolysis in the photoreceptors also leads to a high rate of production of lactate which is transported out of the subretinal space to the choroidal circulation by the RPE. Lactate taken up by the RPE is converted to pyruvate and metabolized via OXPHOS. Excess lactate in the RPE is transported across the basolateral membrane to the choroid. The uptake of glucose by cone photoreceptor cells is enhanced by rod-derived cone viability factor (RdCVF) secreted by rods and by insulin signaling. Together, the three cells act as symbiotes: the RPE supplies the glucose from the choroidal circulation to the photoreceptors, the rods help the cones, and both produce lactate to feed the RPE. In age-related macular degeneration this delicate ménage à trois is disturbed by the chronic infiltration of inflammatory macrophages. These immune cells also rely on aerobic glycolysis and compete for glucose and produce lactate. We here review the glucose metabolism in the homeostasis of the outer retina and in macrophages and hypothesize what happens when the metabolism of photoreceptors and the RPE is disturbed by chronic inflammation.
Collapse
Affiliation(s)
- Thierry Léveillard
- . Department of Genetics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France.
| | - Nancy J Philp
- . Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | - Florian Sennlaub
- . Department of Therapeutics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France.
| |
Collapse
|
26
|
Kanan Y, Khan M, Lorenc VE, Long D, Chadha R, Sciamanna J, Green K, Campochiaro PA. Metipranolol promotes structure and function of retinal photoreceptors in the rd10 mouse model of human retinitis pigmentosa. J Neurochem 2018; 148:307-318. [PMID: 30315650 DOI: 10.1111/jnc.14613] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 10/04/2018] [Accepted: 10/08/2018] [Indexed: 12/24/2022]
Abstract
Metipranolol is a β-adrenergic receptor antagonist that is given orally for the treatment of hypertension and also applied topically to the cornea for treating glaucoma. It also inhibits nitrosative stress which has previously been shown to be the cause of cone photoreceptor death in retinitis pigmentosa. In this study, we tested the hypothesis that metipranolol protects photoreceptor structure and function in the mouse model rd10. At P35, compared with vehicle-treated rd10 mice in which rod degeneration was nearly complete, rd10 mice given daily subcutaneous injections of 40 mg/kg of metipranolol had reduction in markers of nitrosative stress, fewer TUNEL-positive cells, increased outer nuclear layer thickness, and substantially more staining for rhodopsin. This was accompanied by significantly higher mean scotopic and photopic electroretinogram b-wave amplitudes indicating improved photoreceptor function. At P50, metipranolol-treated rd10 mice had decreased 3-nitrotyrosine staining in the retina, increased immunostaining for cone arrestin, a marker for cone photoreceptors, and significantly higher scotopic and photopic b-wave amplitudes at the highest stimulus intensity compared with vehicle-treated mice. At P65, cone density was significantly higher in metipranolol-treated versus vehicle-injected rd10 mice. Metipranolol applied as eye drops promoted cone photoreceptor function in retinas of rd10 mice greater than subcutaneously injected metipranolol. The reduced nitrosative damage and rescue of functional loss of photoreceptors in rd10 mice suggests that metipranolol, a drug with established ocular safety and tolerability, may have potential for treating patients with retinitis pigmentosa.
Collapse
Affiliation(s)
- Yogita Kanan
- Departments of Ophthalmology and Neuroscience, The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Mahmood Khan
- Departments of Ophthalmology and Neuroscience, The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Valeria E Lorenc
- Departments of Ophthalmology and Neuroscience, The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Da Long
- Departments of Ophthalmology and Neuroscience, The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Rishi Chadha
- Departments of Ophthalmology and Neuroscience, The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jason Sciamanna
- Departments of Ophthalmology and Neuroscience, The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ken Green
- Alimera Sciences, 6120 Windward Parkway, Alpharetta, Georgia, USA
| | - Peter A Campochiaro
- Departments of Ophthalmology and Neuroscience, The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
27
|
Samarajeewa A, Lenz DR, Xie L, Chiang H, Kirchner R, Mulvaney JF, Edge ASB, Dabdoub A. Transcriptional response to Wnt activation regulates the regenerative capacity of the mammalian cochlea. Development 2018; 145:dev.166579. [PMID: 30389848 PMCID: PMC6288390 DOI: 10.1242/dev.166579] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 10/25/2018] [Indexed: 01/04/2023]
Abstract
Lack of sensory hair cell (HC) regeneration in mammalian adults is a major contributor to hearing loss. In contrast, the neonatal mouse cochlea retains a transient capacity for regeneration, and forced Wnt activation in neonatal stages promotes supporting cell (SC) proliferation and induction of ectopic HCs. We currently know little about the temporal pattern and underlying mechanism of this age-dependent regenerative response. Using an in vitro model, we show that Wnt activation promotes SC proliferation following birth, but prior to postnatal day (P) 5. This age-dependent decline in proliferation occurs despite evidence that the Wnt pathway is postnatally active and can be further enhanced by Wnt stimulators. Using an in vivo mouse model and RNA sequencing, we show that proliferation in the early neonatal cochlea is correlated with a unique transcriptional response that diminishes with age. Furthermore, we find that augmenting Wnt signaling through the neonatal stages extends the window for HC induction in response to Notch signaling inhibition. Our results suggest that the downstream transcriptional response to Wnt activation, in part, underlies the regenerative capacity of the mammalian cochlea. Summary: Canonical Wnt activation in the mammalian cochlea elicits a unique, age-dependent transcriptional response, which in part regulates the regenerative capacity of supporting cells during cochlear maturation.
Collapse
Affiliation(s)
- Anshula Samarajeewa
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto ON, M5S 1A8, Canada
| | - Danielle R Lenz
- Department of Otolaryngology, Harvard Medical School, Boston, MA 02114, USA.,Eaton-Peabody Laboratory, Massachusetts Eye and Ear, Boston, MA 02114, USA
| | - Lihong Xie
- Biological Sciences, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto ON, M4N 3M5, Canada.,Department of Otolaryngology-Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning Guangxi, 530021, China
| | - Hao Chiang
- Department of Otolaryngology, Harvard Medical School, Boston, MA 02114, USA.,Eaton-Peabody Laboratory, Massachusetts Eye and Ear, Boston, MA 02114, USA
| | - Rory Kirchner
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Joanna F Mulvaney
- Biological Sciences, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto ON, M4N 3M5, Canada
| | - Albert S B Edge
- Department of Otolaryngology, Harvard Medical School, Boston, MA 02114, USA.,Eaton-Peabody Laboratory, Massachusetts Eye and Ear, Boston, MA 02114, USA
| | - Alain Dabdoub
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto ON, M5S 1A8, Canada .,Biological Sciences, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto ON, M4N 3M5, Canada.,Department of Otolaryngology - Head & Neck Surgery, University of Toronto, Toronto ON, M5G 2C4, Canada
| |
Collapse
|
28
|
Maintaining Cone Function in Rod-Cone Dystrophies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1074:499-509. [PMID: 29721982 DOI: 10.1007/978-3-319-75402-4_62] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Retinal degenerative diseases are a major cause of untreatable blindness due to a loss of photoreceptors. Recent advances in genetics and gene therapy for inherited retinal dystrophies (IRDs) showed that therapeutic gene transfer holds a great promise for vision restoration in people with currently incurable blinding diseases. Due to the huge genetic heterogeneity of IRDs that represents a major obstacle for gene therapy development, alternative therapeutic approaches are needed. This review focuses on the rescue of cone function as a therapeutic option for maintaining central vision in rod-cone dystrophies. It highlights recent developments in better understanding the mechanisms of action of the trophic factor RdCVF and its potential as a sight-saving therapeutic strategy.
Collapse
|
29
|
Campochiaro PA, Mir TA. The mechanism of cone cell death in Retinitis Pigmentosa. Prog Retin Eye Res 2017; 62:24-37. [PMID: 28962928 DOI: 10.1016/j.preteyeres.2017.08.004] [Citation(s) in RCA: 177] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 08/31/2017] [Accepted: 08/31/2017] [Indexed: 12/16/2022]
Abstract
Retinitis Pigmentosa (RP) is a group of diseases in which one of a large number of mutations causes death of rod photoreceptors. After rods die, cone photoreceptors slowly degenerate in a characteristic pattern. The mechanism of rod cell death varies depending upon the gene that is mutated and the rate that rods degenerate is an important prognostic feature, because cones do not begin to degenerate until almost all rods have been eliminated. Rod cell death causes night blindness, but visual disability and blindness result from cone degeneration and therefore it is critical to determine the mechanisms by which it occurs. The death of rods reduces oxygen consumption resulting in high tissue levels of oxygen in the outer retina. The excess oxygen stimulates superoxide radical production by mismatches in the electron transport chain in mitochondria and by stimulation of NADPH oxidase activity in cytoplasm. The high levels of superoxide radicals overwhelm the antioxidant defense system and generate more reactive species including peroxynitrite which is extremely damaging and difficult to detoxify. This results in progressive oxidative damage in cones which contributes to cone cell death and loss of function because drugs or gene transfer that reduce oxidative stress promote cone survival and maintenance of function. Compared with aqueous humor samples from control patients, those from patients with RP show significant elevation of carbonyl content on proteins indicating oxidative damage and a reduction in the ratio of reduced to oxidized glutathione indicating depletion of a major component of the antioxidant defense system from ongoing oxidative stress. The first step in clinical trials will be to identify doses of therapeutic agents that reverse these biomarkers of disease to assist in design of much longer trials with functional and anatomic endpoints.
Collapse
Affiliation(s)
- Peter A Campochiaro
- Departments of Ophthalmology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
| | - Tahreem A Mir
- Departments of Ophthalmology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| |
Collapse
|
30
|
Cell Signaling with Extracellular Thioredoxin and Thioredoxin-Like Proteins: Insight into Their Mechanisms of Action. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:8475125. [PMID: 29138681 PMCID: PMC5613632 DOI: 10.1155/2017/8475125] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/06/2017] [Accepted: 07/17/2017] [Indexed: 12/17/2022]
Abstract
Thioredoxins are small thiol-oxidoreductase enzymes that control cellular redox homeostasis. Paradoxically, human thioredoxin (TXN1) was first identified as the adult T cell leukemia-derived factor (ADF), a secreted protein. ADF has been implicated in a wide variety of cell-to-cell communication systems acting as a cytokine or a chemokine. TRX80 is a truncated TXN1 protein with cytokine activity. The unconventional secretion mechanism of these extracellular thioredoxins is unknown. The thioredoxin system is relying on glucose metabolism through the pentose phosphate pathway that provides reducing power in the form of NADPH, the cofactor of thioredoxin reductase (TXNRD). While a complete extracellular TXN system is present in the blood in the form of circulating TXN1 and TXNDR1, the source of extracellular NADPH remains a mystery. In the absence of redox regenerating capacity, extracellular thioredoxins may rather be prooxidant agents. Rod-derived cone viability factor (RdCVF) is the product of intron retention of the nucleoredoxin-like 1 (NXNL1) gene, a secreted truncated thioredoxin-like protein. The other product encoded by the gene, RdCVFL, is an enzymatically active thioredoxin. This is a very singular example of positive feedback of a superthioredoxin system encoded by a single gene likely emerging during evolution from metabolic constraints on redox signaling.
Collapse
|
31
|
Metabolic and redox signaling in the retina. Cell Mol Life Sci 2016; 74:3649-3665. [PMID: 27543457 PMCID: PMC5597695 DOI: 10.1007/s00018-016-2318-7] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 07/21/2016] [Accepted: 07/22/2016] [Indexed: 01/04/2023]
Abstract
Visual perception by photoreceptors relies on the interaction of incident photons from light with a derivative of vitamin A that is covalently linked to an opsin molecule located in a special subcellular structure, the photoreceptor outer segment. The photochemical reaction produced by the photon is optimal when the opsin molecule, a seven-transmembrane protein, is embedded in a lipid bilayer of optimal fluidity. This is achieved in vertebrate photoreceptors by a high proportion of lipids made with polyunsaturated fatty acids, which have the detrimental property of being oxidized and damaged by light. Photoreceptors cannot divide, but regenerate their outer segments. This is an enormous energetic challenge that explains why photoreceptors metabolize glucose through aerobic glycolysis, as cancer cells do. Uptaken glucose produces metabolites to renew that outer segment as well as reducing power through the pentose phosphate pathway to protect photoreceptors against oxidative damage.
Collapse
|
32
|
Mathematical Model of the Role of RdCVF in the Coexistence of Rods and Cones in a Healthy Eye. Bull Math Biol 2016; 78:1394-409. [DOI: 10.1007/s11538-016-0185-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 06/03/2016] [Indexed: 10/21/2022]
|