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Kim SY, Song MJ, Kim IB, Park TK, Lyu J. Photobiomodulation therapy activates YAP and triggers proliferation and dedifferentiation of Müller glia in mammalian retina. BMB Rep 2023; 56:502-507. [PMID: 37254570 PMCID: PMC10547971 DOI: 10.5483/bmbrep.2023-0059] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/16/2023] [Accepted: 05/28/2023] [Indexed: 04/08/2024] Open
Abstract
Photobiomodulation therapy has been proposed as a promising therapeutic approach for retinal degenerative diseases. However, its effect on the regenerative capacity in mammalian retina and its intracellular signalling mechanisms remain unknown. Here, we show that photobiomodulation with 670 nm light stimulates Müller glia cell cycle re-entry and dedifferentiation into a progenitor-like state in both the uninjured and injured retina. We also find that 670 nm light treatment inhibits the Hippo pathway, which is activated in Müller glia following NaIO3-induced retinal injury. YAP, a major downstream effector of the Hippo signalling pathway was translocated into the nucleus of Müller glia along with YAP dephosphorylation in retina treated with 670 nm light. Deficiency of YAP attenuated Müller glia cell cycle re-entry and dedifferentiation. Our data reveal that the Hippo-YAP signalling pathway is associated with the photostimulatory effect on regenerative response in mammalian retina, and suggest a potential therapeutic strategy for retinal degenerative diseases. [BMB Reports 2023; 56(9): 502-507].
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Affiliation(s)
- Seo-Yeon Kim
- Myung-Gok Eye Research Institute, Konyang University, Daejeon 35365, Korea
- Department of Medical Science, Konyang University, Daejeon 35365, Korea
| | - Myung-Jun Song
- Myung-Gok Eye Research Institute, Konyang University, Daejeon 35365, Korea
- Department of Medical Science, Konyang University, Daejeon 35365, Korea
| | - In-Beom Kim
- Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Tae Kwan Park
- Department of Ophthalmology, Soonchunhyang University Hospital Bucheon, Soonchunhyang University, Bucheon 14584, Korea
| | - Jungmook Lyu
- Myung-Gok Eye Research Institute, Konyang University, Daejeon 35365, Korea
- Department of Medical Science, Konyang University, Daejeon 35365, Korea
- Department of Optometry & Visual Science, Konyang University, Daejeon 35365, Korea
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2
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Kim SY, Song MJ, Kim IB, Park TK, Lyu J. Photobiomodulation therapy activates YAP and triggers proliferation and dedifferentiation of Müller glia in mammalian retina. BMB Rep 2023; 56:502-507. [PMID: 37254570 PMCID: PMC10547971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/16/2023] [Accepted: 05/28/2023] [Indexed: 06/01/2023] Open
Abstract
Photobiomodulation therapy has been proposed as a promising therapeutic approach for retinal degenerative diseases. However, its effect on the regenerative capacity in mammalian retina and its intracellular signalling mechanisms remain unknown. Here, we show that photobiomodulation with 670 nm light stimulates Müller glia cell cycle re-entry and dedifferentiation into a progenitor-like state in both the uninjured and injured retina. We also find that 670 nm light treatment inhibits the Hippo pathway, which is activated in Müller glia following NaIO3-induced retinal injury. YAP, a major downstream effector of the Hippo signalling pathway was translocated into the nucleus of Müller glia along with YAP dephosphorylation in retina treated with 670 nm light. Deficiency of YAP attenuated Müller glia cell cycle re-entry and dedifferentiation. Our data reveal that the Hippo-YAP signalling pathway is associated with the photostimulatory effect on regenerative response in mammalian retina, and suggest a potential therapeutic strategy for retinal degenerative diseases. [BMB Reports 2023; 56(9): 502-507].
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Affiliation(s)
- Seo-Yeon Kim
- Myung-Gok Eye Research Institute, Konyang University, Daejeon 35365, Korea
- Department of Medical Science, Konyang University, Daejeon 35365, Korea
| | - Myung-Jun Song
- Myung-Gok Eye Research Institute, Konyang University, Daejeon 35365, Korea
- Department of Medical Science, Konyang University, Daejeon 35365, Korea
| | - In-Beom Kim
- Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Tae Kwan Park
- Department of Ophthalmology, Soonchunhyang University Hospital Bucheon, Soonchunhyang University, Bucheon 14584, Korea
| | - Jungmook Lyu
- Myung-Gok Eye Research Institute, Konyang University, Daejeon 35365, Korea
- Department of Medical Science, Konyang University, Daejeon 35365, Korea
- Department of Optometry & Visual Science, Konyang University, Daejeon 35365, Korea
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3
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Kim J, Won JY. Effect of Photobiomodulation in Suppression of Oxidative Stress on Retinal Pigment Epithelium. Int J Mol Sci 2022; 23:ijms23126413. [PMID: 35742861 PMCID: PMC9224180 DOI: 10.3390/ijms23126413] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/04/2022] [Accepted: 06/07/2022] [Indexed: 11/16/2022] Open
Abstract
As the world undergoes aging, the number of age-related diseases has increased. One of them is disease related to retinal pigment epithelium (RPE) degeneration, such as age-related macular degeneration, causing vision loss without physical damage in the ocular system. It is the leading cause of blindness, with no cure. Although the exact pathogenesis is still unknown, the research shows that oxidative stress is one of the risk factors. Various molecules have been reported as anti-oxidative materials; however, the disease has not yet been conquered. Here, we would like to introduce photobiomodulation (PBM). PBM is a non-invasive treatment based on red and near-infrared light and has been used to cure various diseases by regulating cellular functions. Furthermore, recent studies showed its antioxidant effect, and due to this reason, PBM is arising as a new treatment for ocular disease. In this study, we confirm the antioxidant effect of PBM in retinal pigment epithelium via an RPE model with hypoxia. The function of RPE is protected by PBM against damage from hypoxia. Furthermore, we observed the protective mechanism of PBM by its suppression effect on reactive oxygen species generation. These results indicate that PBM shows great potential to cure RPE degeneration to help patients with blindness.
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Affiliation(s)
- Jongmin Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea;
| | - Jae Yon Won
- Department of Ophthalmology and Visual Science, Eunpyeong St. Mary’s Hospital, The Catholic University of Korea, Seoul 03312, Korea
- Catholic Institute for Visual Science, College of Medicine, The Catholic University of Korea, Seoul 14662, Korea
- Correspondence:
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4
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Kaynezhad P, Fosbury R, Hogg C, Tachtsidis I, Sivaprasad S, Jeffery G. Near infrared spectroscopy reveals instability in retinal mitochondrial metabolism and haemodynamics with blue light exposure at environmental levels. JOURNAL OF BIOPHOTONICS 2022; 15:e202100283. [PMID: 35020273 DOI: 10.1002/jbio.202100283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/17/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
Blue light (~400-470 nm) is considered potentially detrimental to the retina but is present in natural environmental light. Mitochondrial density is highest in the retina, and they exhibit a prominent optical absorption around 420 nm arising from the Soret band of their porphyrins, including in cytochrome-c-oxidase in their respiratory chain. We examine the impact of continuous 420 nm at environmental energy levels on retinal mitochondrial metabolism and haemodynamics in vivo in real time using broadband near-infrared spectroscopy. One hour environmental exposure to 420 nm induces significant metabolic instability in retinal mitochondria and blood signals, which continues for up to 1 h post blue exposure. Porphyrins are important in mitochondrial adenosine triphosphate (ATP) production and cytochrome-c-oxidase is a key part of the electron transport chain through which this is achieved. Hence, environmental 420 nm likely restricts respiration and ATP production that may impact on retinal function.
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Affiliation(s)
- Pardis Kaynezhad
- University College London, Institute of Ophthalmology, London, United Kingdom
| | - Robert Fosbury
- University College London, Institute of Ophthalmology, London, United Kingdom
- European Southern Observatory, Garching bei München, Germany
| | - Chris Hogg
- University College London, Institute of Ophthalmology, London, United Kingdom
| | - Ilias Tachtsidis
- University College London Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Sobha Sivaprasad
- University College London, Institute of Ophthalmology, London, United Kingdom
| | - Glen Jeffery
- University College London, Institute of Ophthalmology, London, United Kingdom
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5
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Abd Eldaiem MS, Ahmed SA, Elsaeid AA, Hassan AA, Ghoneim DF, Ibrahim AM. Light-Emitting Diode Laser Therapy for Hyperoxia-Induced Retinal Abnormalities. J Lasers Med Sci 2021; 12:e64. [DOI: 10.34172/jlms.2021.64] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 06/27/2021] [Indexed: 01/04/2023]
Abstract
Introduction: Hyperoxygenation is linked to numerous effects in a variety of organ systems. It can cause tissue damage by generating reactive oxygen species (ROS), increasing oxidative stress, and inducing cell death by apoptosis. The present study aimed to evaluate the effects of low-level laser therapy on the retina in response to acute hyperoxia in animals. Methods: A total of 70 Wistar albino rats were evaluated in the present study: 10 rats were designated as a control group, and the rest were exposed to hyperoxia (O2 , 90%) for 3 days, 1 week, and 2 weeks (20 rats each). Each group was divided into two subgroups (n=10), one of which was designated as hyperoxia only. The other was treated with a 670 nm light-emitting diode laser (2 sessions/one week, ~ 9.0 J/cm2 ) in each eye. The animals were euthanized, and their retinas were dissected for analysis of protein content, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), total antioxidant capacity (TAC), hydrogen peroxide (H2 O2 ), malondialdehyde (MDA), and histological examination. Results: We found that two weeks of hyperoxia induced an increase in retinal protein content (P<0.001), an alteration in the intensities and molecular weights of protein fractions, a significant decrease in the TAC level (P<0.01), and a noticeable increase in H2 O2 and MDA levels (P<0.001). Histological examination revealed fragmentation of the photoreceptors and neovascularization in the outer and inner plexiform layers. Furthermore, the data showed remarkable improvement in the retinal protein contents, oxidative state, and retinal structure after light-emitting diode laser therapy. Conclusion: Light-emitting diode laser therapy was found to be a useful treatment paradigm for reducing hyperoxia-induced retinal damage.
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Affiliation(s)
| | - Salwa Abdelkawi Ahmed
- Biophysics and Laser Science Unit, Vision Sciences Department, Research Institute of Ophthalmology, Giza, Egypt
| | | | - Aziza Ahmed Hassan
- Ophthalmic Unit, National Institute of Laser enhanced Science, Cairo University, Cairo, Egypt
| | - Dina Fouad Ghoneim
- Ophthalmic Unit, National Institute of Laser enhanced Science, Cairo University, Cairo, Egypt
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Muste JC, Russell MW, Singh RP. Photobiomodulation Therapy for Age-Related Macular Degeneration and Diabetic Retinopathy: A Review. Clin Ophthalmol 2021; 15:3709-3720. [PMID: 34511875 PMCID: PMC8421781 DOI: 10.2147/opth.s272327] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/24/2021] [Indexed: 01/11/2023] Open
Abstract
Purpose Photobiomodulation therapy (PBT) has emerged as a possible treatment for age-related macular degeneration (AMD) and diabetic retinopathy (DR). This review seeks to summarize the application of PBT in AMD and DR. Methods The National Clinical Trial (NCT) database and PubMed were queried using a literature search strategy and reviewed by the authors. Results Fourteen studies examining the application of PBT for AMD and nine studies examining the application of PBT for diabetic macular edema (DME) were extracted from 60 candidate publications. Discussion Despite notable methodological differences between studies, PBT has been reported to treat certain DR and AMD patients. DR patients with center involving DME and VA ≥ 20/25 have demonstrated response to treatment. AMD patients at Age-Related Eye Disease Study Stages 2–4 with VA ≥20/200 have also shown response to treatment. Results of major clinical trials are pending. Conclusion PBT remains an emergent therapy with possible applications in DR and AMD. Further, high powered studies monitored by a neutral party with standard devices, treatment delivery and treatment timing are needed.
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Affiliation(s)
- Justin C Muste
- Center for Ophthalmic Bioinformatics, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Matthew W Russell
- Center for Ophthalmic Bioinformatics, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Rishi P Singh
- Center for Ophthalmic Bioinformatics, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
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Muste JC, Kalur A, Iyer A, Valentim CCS, Singh RP. Photobiomodulation therapy in age-related macular degeneration. Curr Opin Ophthalmol 2021; 32:225-232. [PMID: 33606405 DOI: 10.1097/icu.0000000000000742] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW To review the available data supporting the use of photobiomodulation therapy (PBT) in the treatment of age-related macular degeneration (AMD). RECENT FINDINGS PBT might be used in treating nonexudative AMD. Limited evidence suggests that exudative AMD may also benefit from PBT. SUMMARY The optimal device would deliver doses of 60 J/cm2 or more with a multiwavelength composition through the pupil over short treatment intervals. Safe upper limits have not been established. More studies are needed to evaluate the efficacy of PBT in treating exudative and nonexudative AMD.
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Affiliation(s)
- Justin C Muste
- Center for Ophthalmic Bioinformatics, Cole Eye Institute, Cleveland Clinic
| | - Aneesha Kalur
- Center for Ophthalmic Bioinformatics, Cole Eye Institute, Cleveland Clinic
| | - Amogh Iyer
- Center for Ophthalmic Bioinformatics, Cole Eye Institute, Cleveland Clinic
| | | | - Rishi P Singh
- Center for Ophthalmic Bioinformatics, Cole Eye Institute, Cleveland Clinic
- Cole Eye Institute - Retina Service, Cleveland Clinic Foundation, Cleveland, Ohio, USA
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8
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Ebeling MC, Geng Z, Kapphahn RJ, Roehrich H, Montezuma SR, Dutton JR, Ferrington DA. Impaired Mitochondrial Function in iPSC-Retinal Pigment Epithelium with the Complement Factor H Polymorphism for Age-Related Macular Degeneration. Cells 2021; 10:cells10040789. [PMID: 33918210 PMCID: PMC8066149 DOI: 10.3390/cells10040789] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 03/26/2021] [Accepted: 03/29/2021] [Indexed: 12/27/2022] Open
Abstract
Age-related macular degeneration (AMD), the leading cause of vision loss in the elderly, is characterized by loss of the retinal pigment epithelium (RPE). While the disease mechanism remains unclear, prior studies have linked AMD with RPE mitochondrial defects and genetic polymorphisms in the complement pathway. This study used RPE generated from induced pluripotent stem cells (iPSC-RPE), which were derived from human donors with or without AMD and genotyped for the complement factor H (CFH) AMD high-risk allele (rs1061170, Y402H) to investigate whether donor disease state or genotype had a detrimental effect on mitochondrial function and inflammation. Results show that cells derived from donors with AMD display decreased mitochondrial function under conditions of stress and elevated expression of inflammatory markers compared to iPSC-RPE from individuals without AMD. A more pronounced reduction in mitochondrial function and increased inflammatory markers was observed in CFH high-risk cells, irrespective of disease state. These results provide evidence for a previously unrecognized link between CFH and mitochondrial function that could contribute to RPE loss in AMD patients harboring the CFH high-risk genotype.
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Affiliation(s)
- Mara C. Ebeling
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA; (M.C.E.); (R.J.K.); (S.R.M.)
| | - Zhaohui Geng
- Stem Cell Institute, University of Minnesota, Minneapolis, MN 55455, USA;
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Rebecca J. Kapphahn
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA; (M.C.E.); (R.J.K.); (S.R.M.)
| | - Heidi Roehrich
- Histology Core for Vision Research, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Sandra R. Montezuma
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA; (M.C.E.); (R.J.K.); (S.R.M.)
| | - James R. Dutton
- Stem Cell Institute, University of Minnesota, Minneapolis, MN 55455, USA;
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
- Correspondence: (J.R.D.); (D.A.F.); Tel.: +1-612-626-2762 (J.R.D.); +1-612-624-8267 (D.A.F.)
| | - Deborah A. Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA; (M.C.E.); (R.J.K.); (S.R.M.)
- Stem Cell Institute, University of Minnesota, Minneapolis, MN 55455, USA;
- Correspondence: (J.R.D.); (D.A.F.); Tel.: +1-612-626-2762 (J.R.D.); +1-612-624-8267 (D.A.F.)
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9
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Tiwari V, Baptiste BA, Okur MN, Bohr VA. Current and emerging roles of Cockayne syndrome group B (CSB) protein. Nucleic Acids Res 2021; 49:2418-2434. [PMID: 33590097 DOI: 10.1093/nar/gkab085] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/26/2021] [Accepted: 02/01/2021] [Indexed: 12/11/2022] Open
Abstract
Cockayne syndrome (CS) is a segmental premature aging syndrome caused primarily by defects in the CSA or CSB genes. In addition to premature aging, CS patients typically exhibit microcephaly, progressive mental and sensorial retardation and cutaneous photosensitivity. Defects in the CSB gene were initially thought to primarily impair transcription-coupled nucleotide excision repair (TC-NER), predicting a relatively consistent phenotype among CS patients. In contrast, the phenotypes of CS patients are pleiotropic and variable. The latter is consistent with recent work that implicates CSB in multiple cellular systems and pathways, including DNA base excision repair, interstrand cross-link repair, transcription, chromatin remodeling, RNAPII processing, nucleolin regulation, rDNA transcription, redox homeostasis, and mitochondrial function. The discovery of additional functions for CSB could potentially explain the many clinical phenotypes of CSB patients. This review focuses on the diverse roles played by CSB in cellular pathways that enhance genome stability, providing insight into the molecular features of this complex premature aging disease.
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Affiliation(s)
- Vinod Tiwari
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Beverly A Baptiste
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Mustafa N Okur
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Vilhelm A Bohr
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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10
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Latina V, Giacovazzo G, Cordella F, Balzamino BO, Micera A, Varano M, Marchetti C, Malerba F, Florio R, Ercole BB, La Regina F, Atlante A, Coccurello R, Di Angelantonio S, Calissano P, Amadoro G. Systemic delivery of a specific antibody targeting the pathological N-terminal truncated tau peptide reduces retinal degeneration in a mouse model of Alzheimer's Disease. Acta Neuropathol Commun 2021; 9:38. [PMID: 33750467 PMCID: PMC7942014 DOI: 10.1186/s40478-021-01138-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/26/2021] [Indexed: 12/28/2022] Open
Abstract
Retina and optic nerve are sites of extra-cerebral manifestations of Alzheimer's Disease (AD). Amyloid-β (Aβ) plaques and neurofibrillary tangles of hyperphosphorylated tau protein are detected in eyes from AD patients and transgenic animals in correlation with inflammation, reduction of synapses, visual deficits, loss of retinal cells and nerve fiber. However, neither the pathological relevance of other post-translational tau modifications-such as truncation with generation of toxic fragments-nor the potential neuroprotective action induced by their in vivo clearance have been investigated in the context of AD retinal degeneration. We have recently developed a monoclonal tau antibody (12A12mAb) which selectively targets the neurotoxic 20-22 kDa NH2-derived peptide generated from pathological truncation at the N-terminal domain of tau without cross-reacting with its full-length normal protein. Previous studies have shown that 12A12mAb, when intravenously (i.v.)-injected into 6-month-old Tg2576 animals, markedly improves their AD-like, behavioural and neuropathological syndrome. By taking advantage of this well-established tau-directed immunization regimen, we found that 12A12mAb administration also exerts a beneficial action on biochemical, morphological and metabolic parameters (i.e. APP/Aβ processing, tau hyperphosphorylation, neuroinflammation, synaptic proteins, microtubule stability, mitochondria-based energy production, neuronal death) associated with ocular injury in the AD phenotype. These findings prospect translational implications in the AD field by: (1) showing for the first time that cleavage of tau takes part in several pathological changes occurring in vivo in affected retinas and vitreous bodies and that its deleterious effects are successfully antagonized by administration of the specific 12A12mAb; (2) shedding further insights on the tight connections between neurosensory retina and brain, in particular following tau-based immunotherapy. In our view, the parallel response we detected in this preclinical animal model, both in the eye and in the hippocampus, following i.v. 12A12mAb injection opens novel diagnostic and therapeutic avenues for the clinical management of cerebral and extracerebral AD signs in human beings.
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Affiliation(s)
- Valentina Latina
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Giacomo Giacovazzo
- IRCSS Santa Lucia Foundation, Via Fosso del Fiorano 64-65, 00143 Rome, Italy
| | - Federica Cordella
- Department of Physiology and Pharmacology, University of Rome La Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy
- Center for Life Nanoscience, Istituto Italiano Di Tecnologia, Viale Regina Elena 291, 00161 Rome, Italy
| | - Bijorn Omar Balzamino
- Research Laboratories in Ophthalmology, IRCCS - Fondazione Bietti, Via Santo Stefano Rotondo, 6, 00184 Rome, Italy
| | - Alessandra Micera
- Research Laboratories in Ophthalmology, IRCCS - Fondazione Bietti, Via Santo Stefano Rotondo, 6, 00184 Rome, Italy
| | - Monica Varano
- Research Laboratories in Ophthalmology, IRCCS - Fondazione Bietti, Via Santo Stefano Rotondo, 6, 00184 Rome, Italy
| | - Cristina Marchetti
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Francesca Malerba
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Rita Florio
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Bruno Bruni Ercole
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Federico La Regina
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Anna Atlante
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM)-CNR, Via Amendola 122/O, 70126 Bari, Italy
| | - Roberto Coccurello
- IRCSS Santa Lucia Foundation, Via Fosso del Fiorano 64-65, 00143 Rome, Italy
- Institute for Complex System (ISC)-CNR, Via dei Taurini 19, 00185 Rome, Italy
| | - Silvia Di Angelantonio
- Department of Physiology and Pharmacology, University of Rome La Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy
- Center for Life Nanoscience, Istituto Italiano Di Tecnologia, Viale Regina Elena 291, 00161 Rome, Italy
| | - Pietro Calissano
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Giuseppina Amadoro
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
- Institute of Translational Pharmacology (IFT), National Research Council (CNR), Via Fosso del Cavaliere 100, 00133 Rome, Italy
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11
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de Jong S, Gagliardi G, Garanto A, de Breuk A, Lechanteur YTE, Katti S, van den Heuvel LP, Volokhina EB, den Hollander AI. Implications of genetic variation in the complement system in age-related macular degeneration. Prog Retin Eye Res 2021; 84:100952. [PMID: 33610747 DOI: 10.1016/j.preteyeres.2021.100952] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/08/2021] [Accepted: 02/11/2021] [Indexed: 12/23/2022]
Abstract
Age-related macular degeneration (AMD) is the main cause of vision loss among the elderly in the Western world. While AMD is a multifactorial disease, the complement system was identified as one of the main pathways contributing to disease risk. The strong link between the complement system and AMD was demonstrated by genetic associations, and by elevated complement activation in local eye tissue and in the systemic circulation of AMD patients. Several complement inhibitors have been and are being explored in clinical trials, but thus far with limited success, leaving the majority of AMD patients without treatment options to date. This indicates that there is still a gap of knowledge regarding the functional implications of the complement system in AMD pathogenesis and how to bring these towards clinical translation. Many different experimental set-ups and disease models have been used to study complement activation in vivo and in vitro, and recently emerging patient-derived induced pluripotent stem cells and genome-editing techniques open new opportunities to study AMD disease mechanisms and test new therapeutic strategies in the future. In this review we provide an extensive overview of methods employed to understand the molecular processes of complement activation in AMD pathogenesis. We discuss the findings, advantages and challenges of each approach and conclude with an outlook on how recent, exciting developments can fill in current knowledge gaps and can aid in the development of effective complement-targeting therapeutic strategies in AMD.
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Affiliation(s)
- Sarah de Jong
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Giuliana Gagliardi
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Alejandro Garanto
- Department of Human Genetics, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Department of Pediatrics, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Amalia Children's Hospital, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Anita de Breuk
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Yara T E Lechanteur
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Suresh Katti
- Gemini Therapeutics Inc., Cambridge, MA, 02139, USA
| | - Lambert P van den Heuvel
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Amalia Children's Hospital, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Department of Laboratory Medicine, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Elena B Volokhina
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Amalia Children's Hospital, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Department of Laboratory Medicine, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Anneke I den Hollander
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Department of Human Genetics, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands.
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12
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Kaynezhad P, Tachtsidis I, Aboelnour A, Sivaprasad S, Jeffery G. Watching synchronous mitochondrial respiration in the retina and its instability in a mouse model of macular degeneration. Sci Rep 2021; 11:3274. [PMID: 33558624 PMCID: PMC7870852 DOI: 10.1038/s41598-021-82811-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 01/12/2021] [Indexed: 11/09/2022] Open
Abstract
Mitochondrial function declines with age and in some diseases, but we have been unable to analyze this in vivo. Here, we optically examine retinal mitochondrial function as well as choroidal oxygenation and hemodynamics in aging C57 and complement factor H (CFH-/-) mice, proposed models of macular degeneration which suffer early retinal mitochondrial decline. In young C57s mitochondrial populations respire in coupled oscillatory behavior in cycles of ~ 8 min, which is phase linked to choroidal oscillatory hemodynamics. In aging C57s, the oscillations are less regular being ~ 14 min and more dissociated from choroidal hemodynamics. The mitochondrial oscillatory cycles are extended in CFH-/- mice being ~ 16 min and are further dissociated from choroidal hemodynamics. Mitochondrial decline occurs before age-related changes to choroidal vasculature, hence, is the likely origin of oscillatory disruption in hemodynamics. This technology offers a non-invasive technique to detect early retinal disease and its relationship to blood oxygenation in vivo and in real time.
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Affiliation(s)
- Pardis Kaynezhad
- Institute of Ophthalmology, University College London, London, EC1V 9EL, UK
| | - Ilias Tachtsidis
- Department of Medical Physics and Biomedical Engineering, University College London, London, WC1E 6BT, UK
| | - Asmaa Aboelnour
- Histology and Cytology Department, Faculty of Veterinary Medicine, Damanhour University, Damanhour, Egypt
| | - Sobha Sivaprasad
- Institute of Ophthalmology, University College London, London, EC1V 9EL, UK
| | - Glen Jeffery
- Institute of Ophthalmology, University College London, London, EC1V 9EL, UK.
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13
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Shen J, Yang P, Luo X, Li H, Xu Y, Shan J, Yang Z, Liang B. Green light extends Drosophila longevity. Exp Gerontol 2021; 147:111268. [PMID: 33539986 DOI: 10.1016/j.exger.2021.111268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 01/27/2021] [Accepted: 01/29/2021] [Indexed: 12/17/2022]
Abstract
The role of visible light on longevity is incompletely understood. Here we show the effect of visible light in Drosophila melanogaster is wavelength specific. Life span was significantly extended by green light, whereas blue light reduced longevity dramatically, and minor impact was observed with red light. While oxidative stress, heat stress, or caloric restriction does not contribute to the beneficial effect of green light, our study found that the life span extension effect of green light might be mediated by microbiota or photosensitive micronutrients in food medium. In conclusion, we report that green light can extend longevity and present the potential of light as a noninvasive therapy for aging-related diseases.
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Affiliation(s)
- Jie Shen
- College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018, China..
| | - Peijing Yang
- College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Xusheng Luo
- College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Honglin Li
- College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Yifan Xu
- College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Jianying Shan
- College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Zhizhang Yang
- College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Boying Liang
- College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
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14
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Genc AM, Makia MS, Sinha T, Conley SM, Al-Ubaidi MR, Naash MI. Elimination of a Retinal Riboflavin Binding Protein Exacerbates Degeneration in a Model of Cone-Rod Dystrophy. Invest Ophthalmol Vis Sci 2021; 61:17. [PMID: 32516403 PMCID: PMC7415289 DOI: 10.1167/iovs.61.6.17] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Purpose Riboflavin and its cofactors are essential for cellular energy generation, responses to oxidative stress, and overall homeostasis. Retbindin is a novel retina-specific riboflavin binding protein essential for the maintenance of retinal flavin levels, but its function remains poorly understood. To further elucidate the function of retbindin in retinal health and disease, we evaluated its role in retinal degeneration in a cone-rod dystrophy model associated with the R172W mutation in the photoreceptor tetraspanin Prph2. Methods We performed structural, functional, and biochemical characterization of R172W-Prph2 mice with and without retbindin (Rtbdn-/-/Prph2R172W). Results Retbindin is significantly upregulated during degeneration in the R172W model, suggesting that retbindin plays a protective role in retinal degenerative diseases. This hypothesis was supported by our findings that R172W mice lacking retbindin (Rtbdn-/-/Prph2R172W) exhibit functional and structural defects in rods and cones that are significantly worse than in controls. Retinal flavin levels were also altered in the Rtbdn-/-/Prph2R172W retina. However, in contrast to the Rtbdn-/- retina which has reduced flavin levels compared to wild-type, Rtbdn-/-/Prph2R172W retinas exhibited elevated levels of riboflavin and the flavin cofactor FMN. Conclusions These results indicate that retbindin plays a protective role during retinal degeneration, but that its function is more complex than previously thought, and suggest a possible role for retbindin in protecting the retina from phototoxicity associated with unbound flavins. This study highlights the essential role of precisely regulated homeostatic mechanisms in photoreceptors, and shows that disruption of this metabolic balance can contribute to the degenerative process associated with other cellular defects.
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15
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A Pilot Study Evaluating the Effects of 670 nm Photobiomodulation in Healthy Ageing and Age-Related Macular Degeneration. J Clin Med 2020; 9:jcm9041001. [PMID: 32252424 PMCID: PMC7231137 DOI: 10.3390/jcm9041001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/25/2020] [Accepted: 03/31/2020] [Indexed: 12/28/2022] Open
Abstract
Limited evidence suggests that the application of 670 nm of red light alters the course of aged decline. A previous report on 18 patients showed regression of drusen and improvement in visual functions in patients with intermediate age-related macular degeneration (AMD) by 12 months. We evaluated the functional and structural effects of applying 670 nm light to 31 patients with intermediate AMD and 11 people aged 55 years or above with normal retina. The study eyes were treated daily in the morning with a 670 nm hand-held light source housed in a torch-like tube that emitted energy equivalent to 40 mW/cm2 or 4.8J/ cm2 for 2 min at the viewing aperture. Visual function in terms of best-corrected visual acuity, low luminance visual acuity, scotopic thresholds and rod-intercept time were compared between baseline and 1, 3, 6 and 12 months. Structural changes on optical coherence tomography OCT and colour photographs were also assessed. Five withdrew consent voluntarily due to the intensity of the study visit assessments and two developed neovascular AMD and were excluded from further treatment and the analysis. In normal ageing, there was an improvement in scotopic thresholds in the group with no AMD by 1.77dB (p = 0.03) and no other parameters showed any clinically significant change. In eyes with intermediate AMD, there was no significant improvement in any functional or structural changes at any time point up to 12 months although the compliance was good. This pilot study shows that photobiomodulation with 670 nm has no effect in patients who have already progressed to intermediate AMD.
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16
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Mehrzadi S, Hemati K, Reiter RJ, Hosseinzadeh A. Mitochondrial dysfunction in age-related macular degeneration: melatonin as a potential treatment. Expert Opin Ther Targets 2020; 24:359-378. [PMID: 32116056 DOI: 10.1080/14728222.2020.1737015] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Introduction: Age-related Macular Degeneration (AMD), a retinal neurodegenerative disease is the most common cause of blindness among the elderly in developed countries. The impairment of mitochondrial biogenesis has been reported in human retinal pigment epithelium (RPE) cells affected by AMD. Oxidative/nitrosative stress plays an important role in AMD development. The mitochondrial respiratory system is considered a major site of reactive oxygen species (ROS) generation. During aging, insufficient free radical scavenger systems, impairment of DNA repair mechanisms and reduction of mitochondrial degradation and turnover contribute to the massive accumulation of ROS disrupting mitochondrial function. Impaired mitochondrial function leads to the decline in the autophagic capacity and induction of inflammation and apoptosis in human RPE cells affected by AMD.Areas covered: This article evaluates the ameliorative effect of melatonin on AMD and examines AMD pathogenesis with an emphasis on mitochondrial dysfunction. It also considers the potential effects of melatonin on mitochondrial function.Expert opinion: The effect of melatonin on mitochondrial function results in the reduction of oxidative stress, inflammation and apoptosis in the retina; these findings demonstrate that melatonin has the potential to prevent and treat AMD.
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Affiliation(s)
- Saeed Mehrzadi
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Karim Hemati
- Department of Anesthesiology, Iran University of Medical Sciences, Tehran, Iran
| | - Russel J Reiter
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Azam Hosseinzadeh
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran
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17
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Hu X, Calton MA, Tang S, Vollrath D. Depletion of Mitochondrial DNA in Differentiated Retinal Pigment Epithelial Cells. Sci Rep 2019; 9:15355. [PMID: 31653972 PMCID: PMC6814719 DOI: 10.1038/s41598-019-51761-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 09/26/2019] [Indexed: 11/17/2022] Open
Abstract
We investigated the effects of treating differentiated retinal pigment epithelial (RPE) cells with didanosine (ddI), which is associated with retinopathy in individuals with HIV/AIDS. We hypothesized that such treatment would cause depletion of mitochondrial DNA and provide insight into the consequences of degradation of RPE mitochondrial function in aging and disease. Treatment of differentiated ARPE-19 or human primary RPE cells with 200 µM ddI for 6–24 days was not cytotoxic but caused up to 60% depletion of mitochondrial DNA, and a similar reduction in mitochondrial membrane potential and NDUFA9 protein abundance. Mitochondrial DNA-depleted RPE cells demonstrated enhanced aerobic glycolysis by extracellular flux analysis, increased AMP kinase activation, reduced mTOR activity, and increased resistance to cell death in response to treatment with the oxidant, sodium iodate. We conclude that ddI-mediated mitochondrial DNA depletion promotes a glycolytic shift in differentiated RPE cells and enhances resistance to oxidative damage. Our use of ddI treatment to induce progressive depletion of mitochondrial DNA in differentiated human RPE cells should be widely applicable for other studies aimed at understanding RPE mitochondrial dysfunction in aging and disease.
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Affiliation(s)
- Xinqian Hu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China. .,Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA.
| | - Melissa A Calton
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Shibo Tang
- AIER School of Ophthalmology, Central South University, Changsha, China.,AIER Eye Institute, Changsha, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Douglas Vollrath
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA
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18
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Amir Mishan M, Rezaei Kanavi M, Shahpasand K, Ahmadieh H. Pathogenic Tau Protein Species: Promising Therapeutic Targets for Ocular Neurodegenerative Diseases. J Ophthalmic Vis Res 2019; 14:491-505. [PMID: 31875105 PMCID: PMC6825701 DOI: 10.18502/jovr.v14i4.5459] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 06/11/2019] [Indexed: 12/13/2022] Open
Abstract
Tau is a microtubule-associated protein, which is highly expressed in the central nervous system as well as ocular neurons and stabilizes microtubule structure. It is a phospho-protein being moderately phosphorylated under physiological conditions but its abnormal hyperphosphorylation or some post-phosphorylation modifications would result in a pathogenic condition, microtubule dissociation, and aggregation. The aggregates can induce neuroinflammation and trigger some pathogenic cascades, leading to neurodegeneration. Taking these together, targeting pathogenic tau employing tau immunotherapy may be a promising therapeutic strategy in fighting with cerebral and ocular neurodegenerative disorders.
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Affiliation(s)
- Mohammad Amir Mishan
- Ocular Tissue Engineering Research Center, Student Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mozhgan Rezaei Kanavi
- Ocular Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Koorosh Shahpasand
- Department of Brain and Cognitive Sciences, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Hamid Ahmadieh
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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19
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Kam JH, Weinrich TW, Shinhmar H, Powner MB, Roberts NW, Aboelnour A, Jeffery G. Fundamental differences in patterns of retinal ageing between primates and mice. Sci Rep 2019; 9:12574. [PMID: 31467395 PMCID: PMC6715671 DOI: 10.1038/s41598-019-49121-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 08/06/2019] [Indexed: 01/09/2023] Open
Abstract
Photoreceptors have high metabolic demands and age rapidly, undermining visual function. We base our understanding mainly on ageing mice where elevated inflammation, extracellular deposition, including that of amyloid beta, and rod and cone photoreceptor loss occur, but cones are not lost in ageing primate although their function declines, revealing that primate and mouse age differently. We examine ageing primate retinae and show elevated stress but low inflammation. However, aged primates have a >70% reduction in adenosine triphosphate (ATP) and a decrease in cytochrome c oxidase. There is a shift in cone mitochondrial positioning and glycolytic activity increases. Bruch’s membrane thickens but unlike in mice, amyloid beta is absent. Hence, reduced ATP may explain cone functional decline in ageing but their retained presence offers the possibility of functional restoration if they can be fuelled appropriately to restore cellular function. This is important because as humans we largely depend on cone function to see and are rarely fully dark adapted. Presence of limited aged inflammation and amyloid beta deposition question some of the therapeutic approaches taken to resolve problems of retinal ageing in humans and the possible lack of success in clinical trials in macular degeneration that have targeted inflammatory agents.
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Affiliation(s)
- Jaimie Hoh Kam
- University College London, Institute of Ophthalmology, EC1V9EL, London, UK
| | - Tobias W Weinrich
- University College London, Institute of Ophthalmology, EC1V9EL, London, UK
| | - Harpreet Shinhmar
- University College London, Institute of Ophthalmology, EC1V9EL, London, UK
| | - Michael B Powner
- City, University of London, Centre of Applied Vision Research, EC1V0HB, London, UK
| | - Nicholas W Roberts
- School of Biological Sciences, University of Bristol, BS8 1TQ, Bristol, UK
| | - Asmaa Aboelnour
- Histology and Cytology Department, Faculty of Veterinary Medicine, Damanhour University, Damanhour, Egypt
| | - Glen Jeffery
- University College London, Institute of Ophthalmology, EC1V9EL, London, UK.
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20
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Shen J, Tower J. Effects of light on aging and longevity. Ageing Res Rev 2019; 53:100913. [PMID: 31154014 DOI: 10.1016/j.arr.2019.100913] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 05/17/2019] [Accepted: 05/29/2019] [Indexed: 12/11/2022]
Abstract
Increasing evidence suggests an important role for light in regulation of aging and longevity. UV radiation is a mutagen that can promote aging and decrease longevity. In contrast, NIR light has shown protective effects in animal disease models. In invertebrates, visible light can shorten or extend lifespan, depending on the intensity and wavelength composition. Visible light also impacts human health, including retina function, sleep, cancer and psychiatric disorders. Possible mechanisms of visible light include: controlling circadian rhythms, inducing oxidative stress, and acting through the retina to affect neuronal circuits and systems. Changes in artificial lighting (e.g., LEDs) may have implications for human health. It will be important to further explore the mechanisms of how light affects aging and longevity, and how light affects human health.
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21
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Eells JT. Mitochondrial Dysfunction in the Aging Retina. BIOLOGY 2019; 8:biology8020031. [PMID: 31083549 PMCID: PMC6627398 DOI: 10.3390/biology8020031] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/04/2019] [Accepted: 05/09/2019] [Indexed: 12/21/2022]
Abstract
Mitochondria are central in retinal cell function and survival and they perform functions that are critical to cell function. Retinal neurons have high energy requirements, since large amounts of ATP are needed to generate membrane potentials and power membrane pumps. Mitochondria over the course of aging undergo a number of changes. Aged mitochondria exhibit decreased rates of oxidative phosphorylation, increased reactive oxygen species (ROS) generation and increased numbers of mtDNA mutations. Mitochondria in the neural retina and the retinal pigment epithelium are particularly susceptible to oxidative damage with aging. Many age-related retinal diseases, including glaucoma and age-related macular degeneration, have been associated with mitochondrial dysfunction. Therefore, mitochondria are a promising therapeutic target for the treatment of retinal disease.
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Affiliation(s)
- Janis T Eells
- Department of Biomedical Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA.
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22
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Jeffery G, Sivaprasad S. A hidden footprint: embryological origins of age related macular degeneration. Eye (Lond) 2019; 33:1675-1676. [PMID: 30996337 DOI: 10.1038/s41433-019-0444-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 02/22/2019] [Indexed: 11/09/2022] Open
Affiliation(s)
- Glen Jeffery
- Institute of Ophthalmology, University College London, London, UK.
| | - Sobha Sivaprasad
- Institute of Ophthalmology, University College London, London, UK
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23
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Toms M, Burgoyne T, Tracey-White D, Richardson R, Dubis AM, Webster AR, Futter C, Moosajee M. Phagosomal and mitochondrial alterations in RPE may contribute to KCNJ13 retinopathy. Sci Rep 2019; 9:3793. [PMID: 30846767 PMCID: PMC6405871 DOI: 10.1038/s41598-019-40507-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 02/18/2019] [Indexed: 12/29/2022] Open
Abstract
Mutations in KCNJ13 are associated with two retinal disorders; Leber congenital amaurosis (LCA) and snowflake vitreoretinal degeneration (SVD). We examined the retina of kcnj13 mutant zebrafish (obelixtd15, c.502T > C p.[Phe168Leu]) to provide new insights into the pathophysiology underlying these conditions. Detailed phenotyping of obelixtd15 fish revealed a late onset retinal degeneration at 12 months. Electron microscopy of the obelixtd15 retinal pigment epithelium (RPE) uncovered reduced phagosome clearance and increased mitochondrial number and size prior any signs of retinal degeneration. Melanosome distribution was also affected in dark-adapted 12-month obelixtd15 fish. At 6 and 12 months, ATP levels were found to be reduced along with increased expression of glial fibrillary acidic protein and heat shock protein 60. Quantitative RT-PCR of polg2, fis1, opa1, sod1/2 and bcl2a from isolated retina showed expression changes consistent with altered mitochondrial activity and retinal stress. We propose that the retinal disease in this model is primarily a failure of phagosome physiology with a secondary mitochondrial dysfunction. Our findings suggest that alterations in the RPE and photoreceptor cellular organelles may contribute to KCNJ13-related retinal degeneration and provide a therapeutic target.
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Affiliation(s)
- Maria Toms
- UCL Institute of Ophthalmology, London, UK
| | | | | | | | - Adam M Dubis
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Andrew R Webster
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | | | - Mariya Moosajee
- UCL Institute of Ophthalmology, London, UK. .,Moorfields Eye Hospital NHS Foundation Trust, London, UK. .,Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.
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24
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Complement factor H regulates retinal development and its absence may establish a footprint for age related macular degeneration. Sci Rep 2019; 9:1082. [PMID: 30705315 PMCID: PMC6355813 DOI: 10.1038/s41598-018-37673-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 11/29/2018] [Indexed: 01/22/2023] Open
Abstract
Age related macular degeneration (AMD) is the most common blinding disease in those over 60 years. In 50% of cases it is associated with polymorphisms of complement factor H (FH), implicating immune vulnerability. But such individuals may exhibit abnormal outer retinal blood flow decades before disease initiation, suggesting an early disease footprint. FH is expressed in the retinal pigmented epithelium (RPE). During development the RPE is adjacent to the site of retinal mitosis and complex regulatory interactions occur between the relatively mature RPE and retinal neuronal precursors that control the cell cycle. Here we ask if the absence of FH from the RPE influences retinal development using a mouse CFH knockout (Cfh−/−) with an aged retinal degenerative phenotype. We reveal that from birth, these mice have significantly disrupted and delayed retinal development. However, once development is complete, their retinae appear relatively normal, although many photoreceptor and RPE mitochondria are abnormally large, suggesting dysfunction consistent with premature ATP decline in Cfh−/−. Total retinal mtDNA is also reduced and these deficits are associated shortly after with reduced retinal function. Cfh−/+ mice also show significant abnormal patterns of cell production but not as great as in Cfh−/−. These results reveal that not only is FH an important player in sculpting retinal development but also that the developmental abnormality in Cfh−/− likely establishes critical vulnerability for later aged retinal degeneration.
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25
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Perez-Pepe M, Fernández-Alvarez AJ, Boccaccio GL. Life and Work of Stress Granules and Processing Bodies: New Insights into Their Formation and Function. Biochemistry 2018; 57:2488-2498. [PMID: 29595960 DOI: 10.1021/acs.biochem.8b00025] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The dynamic formation of stress granules (SGs), processing bodies (PBs), and related RNA organelles regulates diverse cellular processes, including the coordination of functionally connected messengers, the translational regulation at the synapse, and the control of viruses and retrotransposons. Recent studies have shown that pyruvate kinase and other enzymes localize in SGs and PBs, where they become protected from stress insults. These observations may have implications for enzyme regulation and metabolic control exerted by RNA-based organelles. The formation of these cellular bodies is governed by liquid-liquid phase separation (LLPS) processes, and it needs to be strictly controlled to prevent pathogenic aggregation. The intracellular concentration of key metabolites, such as ATP and sterol derivatives, may influence protein solubility, thus affecting the dynamics of liquid organelles. LLPS in vitro depends on the thermal diffusion of macromolecules, which is limited inside cells, where the condensation and dissolution of membrane-less organelles are helped by energy-driven processes. The active transport by the retrograde motor dynein helps SG assembly, whereas the anterograde motor kinesin mediates SG dissolution; a tug of war between these two molecular motors allows transient SG formation. There is evidence that the efficiency of dynein-mediated transport increases with the number of motor molecules associated with the cargo. The dynein-dependent transport may be influenced by cargo size as larger cargos can load a larger number of motors. We propose a model based on this emergent property of dynein motors, which would be collectively stronger during SG condensation and weaker during SG breakdown, thus allowing kinesin-mediated dispersion.
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Affiliation(s)
- Marcelo Perez-Pepe
- Instituto Leloir and Instituto de Investigaciones Bioquı́micas de Buenos Aires (IIBBA)-CONICET , Buenos Aires , Argentina
| | - Ana J Fernández-Alvarez
- Instituto Leloir and Instituto de Investigaciones Bioquı́micas de Buenos Aires (IIBBA)-CONICET , Buenos Aires , Argentina
| | - Graciela L Boccaccio
- Instituto Leloir and Instituto de Investigaciones Bioquı́micas de Buenos Aires (IIBBA)-CONICET , Buenos Aires , Argentina
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26
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670nm light treatment following retinal injury modulates Müller cell gliosis: Evidence from in vivo and in vitro stress models. Exp Eye Res 2018; 169:1-12. [PMID: 29355737 DOI: 10.1016/j.exer.2018.01.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/04/2018] [Accepted: 01/12/2018] [Indexed: 11/22/2022]
Abstract
Photobiomodulation (PBM) with 670 nm light has been shown to accelerate wound healing in soft tissue injuries, and also to protect neuronal tissues. However, little data exist on its effects on the non-neuronal components of the retina, such as Müller cells (MCs), which are the principal macroglia of the retina that play a role in maintaining retinal homeostasis. The aim of this study was to explore the effects of 670 nm light on activated MCs using in vivo and in vitro stress models. Adult Sprague-Dawley rats were exposed to photo-oxidative damage (PD) for 24 h and treated with 670 nm light at 0, 3 and 14 days after PD. Tissue was collected at 30 days post-PD for analysis. Using the in vitro scratch model with a human MC line (MIO-M1), area coverage and cellular stress were analysed following treatment with 670 nm light. We showed that early treatment with 670 nm light after PD reduced MC activation, lowering the retinal expression of GFAP and FGF-2. 670 nm light treatment mitigated the production of MC-related pro-inflammatory cytokines (including IL-1β), and reduced microglia/macrophage (MG/MΦ) recruitment into the outer retina following PD. This subsequently decreased photoreceptor loss, slowing the progression of retinal degeneration. In vitro, we showed that 670 nm light directly modulated MC activation, reducing rates of area coverage by suppressing cellular proliferation and spreading. This study indicates that 670 nm light treatment post-injury may have therapeutic benefit when administered shortly after retinal damage, and could be useful for retinal degenerations where MC gliosis is a feature of disease progression.
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27
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Ao J, Wood JP, Chidlow G, Gillies MC, Casson RJ. Retinal pigment epithelium in the pathogenesis of age-related macular degeneration and photobiomodulation as a potential therapy? Clin Exp Ophthalmol 2018; 46:670-686. [PMID: 29205705 DOI: 10.1111/ceo.13121] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/27/2017] [Accepted: 11/28/2017] [Indexed: 12/11/2022]
Abstract
The retinal pigment epithelium (RPE) comprises a monolayer of cells located between the neuroretina and the choriocapillaries. The RPE serves several important functions in the eye: formation of the blood-retinal barrier, protection of the retina from oxidative stress, nutrient delivery and waste disposal, ionic homeostasis, phagocytosis of photoreceptor outer segments, synthesis and release of growth factors, reisomerization of all-trans-retinal during the visual cycle, and establishment of ocular immune privilege. Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries. Dysfunction of the RPE has been associated with the pathogenesis of AMD in relation to increased oxidative stress, mitochondrial destabilization and complement dysregulation. Photobiomodulation or near infrared light therapy which refers to non-invasive irradiation of tissue with light in the far-red to near-infrared light spectrum (630-1000 nm), is an intervention that specifically targets key mechanisms of RPE dysfunction that are implicated in AMD pathogenesis. The current evidence for the efficacy of photobiomodulation in AMD is poor but its safety profile and proposed mechanisms of action motivate further research as a novel therapy for AMD.
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Affiliation(s)
- Jack Ao
- South Australian Institute of Ophthalmology, University of Adelaide, Adelaide, South Australia, Australia
| | - John Pm Wood
- South Australian Institute of Ophthalmology, University of Adelaide, Adelaide, South Australia, Australia
| | - Glyn Chidlow
- South Australian Institute of Ophthalmology, University of Adelaide, Adelaide, South Australia, Australia
| | - Mark C Gillies
- The Save Sight Institute, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Robert J Casson
- South Australian Institute of Ophthalmology, University of Adelaide, Adelaide, South Australia, Australia
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Aboelnour A, Van der Spuy J, Powner M, Jeffery G. Primate retinal cones express phosphorylated tau associated with neuronal degeneration yet survive in old age. Exp Eye Res 2017; 165:105-108. [PMID: 28974357 PMCID: PMC5725308 DOI: 10.1016/j.exer.2017.09.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 09/22/2017] [Accepted: 09/28/2017] [Indexed: 01/24/2023]
Abstract
Photoreceptor cells have high energy demands and suffer significantly with age. In aged rodents both rods and cones are lost, but in primates there is no evidence for aged cone loss, although their function declines. Here we ask if aged primate cones suffer from reduced function because of declining metabolic ability. Tau is a microtubule associated protein critical for mitochondrial function in neurons. Its phosphorylation is a feature of neuronal degeneration undermining respiration and mitochondrial dynamics. We show that total tau is widely distributed in the primate outer retina with little age-related change, being present in both rods and cones and their processes. However, all cones specifically accumulate phosphorylated tau, which was not seen in rods. The presence of this protein will likely undermine cone cell function. However, tau phosphorylation inhibits apoptosis. These data may explain why aged primate cones have reduced function but appear to be resistant to cell death. Consequently, therapies designed to remove phosphorylated tau may carry the risk of inducing cone photoreceptor cell death and further undermine ageing visual function.
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Affiliation(s)
- Asmaa Aboelnour
- Histology and Cytology Department, Faculty of Veterinary Medicine, Damanhour University, Egypt
| | | | - Michael Powner
- Department of Optometry and Visual Science, City University London, UK
| | - Glen Jeffery
- Institute of Ophthalmology, University College London, UK.
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29
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Lu YZ, Natoli R, Madigan M, Fernando N, Saxena K, Aggio-Bruce R, Jiao H, Provis J, Valter K. Photobiomodulation with 670 nm light ameliorates Müller cell-mediated activation of microglia and macrophages in retinal degeneration. Exp Eye Res 2017; 165:78-89. [PMID: 28888911 DOI: 10.1016/j.exer.2017.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 09/03/2017] [Accepted: 09/05/2017] [Indexed: 12/21/2022]
Abstract
Müller cells, the supporting cells of the retina, play a key role in responding to retinal stress by releasing chemokines, including CCL2, to recruit microglia and macrophages (MG/MΦ) into the damaged retina. Photobiomodulation (PBM) with 670 nm light has been shown to reduce inflammation in models of retinal degeneration. In this study, we aimed to investigate whether 670 nm light had an effect on Müller cell-initiated inflammation under retinal photo-oxidative damage (PD) in vivo and in vitro. Sprague-Dawley rats were pre-treated with 670 nm light (9J/cm2) once daily over 5 days prior to PD. The expression of inflammatory genes including CCL2 and IL-1β was analysed in retinas. In vitro, primary Müller cells dissociated from neonatal rat retinas were co-cultured with 661W photoreceptor cells. Co-cultures were exposed to PD, followed by 670 nm light treatment to the Müller cells only, and Müller cell stress and inflammation were assessed. Primary MG/MΦ were incubated with supernatant from the co-cultures, and collected for analysis of inflammatory activation. To further understand the mechanism of 670 nm light, the expression of COX5a and mitochondrial membrane potential (ΔΨm) were measured in Müller cells. Following PD, 670 nm light-treated Müller cells had a reduced inflammatory activation, with lower levels of CCL2, IL-1β and IL-6. Supernatant from 670 nm light-treated co-cultures reduced activation of primary MG/MΦ, and lowered the expression of pro-inflammatory cytokines, compared to untreated PD controls. Additionally, 670 nm light-treated Müller cells had an increased expression of COX5a and an elevated ΔΨm following PD, suggesting that retrograde signaling plays a role in the effects of 670 nm light on Müller cell gene expression. Our data indicates that 670 nm light reduces Müller cell-mediated retinal inflammation, and offers a potential cellular mechanism for 670 nm light therapy in regulating inflammation associated with retinal degenerations.
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Affiliation(s)
- Yen-Zhen Lu
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Riccardo Natoli
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia; ANU Medical School, The Australian National University, Canberra, ACT, Australia
| | - Michele Madigan
- Save Sight Institute, Discipline of Clinical Ophthalmology, The University of Sydney, Sydney, NSW, Australia; School of Optometry and Vision Science, The University of New South Wales, Kensington, NSW, Australia
| | - Nilisha Fernando
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Kartik Saxena
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Riemke Aggio-Bruce
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Haihan Jiao
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Jan Provis
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia; ANU Medical School, The Australian National University, Canberra, ACT, Australia
| | - Krisztina Valter
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia; ANU Medical School, The Australian National University, Canberra, ACT, Australia.
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Weinrich TW, Coyne A, Salt TE, Hogg C, Jeffery G. Improving mitochondrial function significantly reduces metabolic, visual, motor and cognitive decline in aged Drosophila melanogaster. Neurobiol Aging 2017; 60:34-43. [PMID: 28917665 DOI: 10.1016/j.neurobiolaging.2017.08.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 08/09/2017] [Accepted: 08/18/2017] [Indexed: 01/01/2023]
Abstract
Mitochondria play a major role in aging. Over time, mutations accumulate in mitochondrial DNA leading to reduced adenosine triphosphate (ATP) production and increased production of damaging reactive oxygen species. If cells fail to cope, they die. Reduced ATP will result in declining cellular membrane potentials leading to reduced central nervous system function. However, aged mitochondrial function is improved by long wavelength light (670 nm) absorbed by cytochrome c oxidase in mitochondrial respiration. In Drosophila, lifelong 670-nm exposure extends lifespan and improves aged mobility. Here, we ask if improved mitochondrial metabolism can reduce functional senescence in metabolism, sensory, locomotor, and cognitive abilities in old flies exposed to 670 nm daily for 1 week. Exposure significantly increased cytochrome c oxidase activity, whole body energy storage, ATP and mitochondrial DNA content, and reduced reactive oxygen species. Retinal function and memory were also significantly improved to levels found in 2-week-old flies. Mobility improved by 60%. The mode of action is likely related to improved energy homeostasis increasing ATP availability for ionic ATPases critical for maintenance of neuronal membrane potentials. 670-nm light exposure may be a simple route for resolving problems of aging.
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Affiliation(s)
| | - Ariathney Coyne
- University College London, Institute of Ophthalmology, London, UK
| | - Thomas E Salt
- University College London, Institute of Ophthalmology, London, UK; Neurexpert Ltd., London, UK
| | - Christopher Hogg
- University College London, Institute of Ophthalmology, London, UK
| | - Glen Jeffery
- University College London, Institute of Ophthalmology, London, UK.
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31
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Mitochondrial dysfunction underlying outer retinal diseases. Mitochondrion 2017; 36:66-76. [PMID: 28365408 DOI: 10.1016/j.mito.2017.03.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 03/06/2017] [Accepted: 03/27/2017] [Indexed: 01/21/2023]
Abstract
Dysfunction of photoreceptors, retinal pigment epithelium (RPE) or both contribute to the initiation and progression of several outer retinal disorders. Disrupted Müller glia function might additionally subsidize to these diseases. Mitochondrial malfunctioning is importantly associated with outer retina pathologies, which can be classified as primary and secondary mitochondrial disorders. This review highlights the importance of oxidative stress and mitochondrial DNA damage, underlying outer retinal disorders. Indeed, the metabolically active photoreceptors/RPE are highly prone to these hallmarks of mitochondrial dysfunction, indicating that mitochondria represent a weak link in the antioxidant defenses of outer retinal cells.
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Sivapathasuntharam C, Sivaprasad S, Hogg C, Jeffery G. Aging retinal function is improved by near infrared light (670 nm) that is associated with corrected mitochondrial decline. Neurobiol Aging 2017; 52:66-70. [PMID: 28129566 PMCID: PMC5364001 DOI: 10.1016/j.neurobiolaging.2017.01.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 01/01/2017] [Accepted: 01/02/2017] [Indexed: 11/01/2022]
Abstract
Aging is associated with cellular decline and reduced function, partly mediated by mitochondrial compromise. However, aged mitochondrial function is corrected with near infrared light (670 nm) that improves their membrane potentials and adenosine triphosphate production and also reduces age-related inflammation. We ask if 670 nm light can also improve declining retinal function. Electroretinograms were measured in 2-, 7-, and 12-month old C57BL/6 mice. Significant age-related declines were measured in the photoreceptor generated a-wave and the postreceptoral b-wave. Seven- and 12-month-old mice were exposed to 670 nm for 15 minutes daily over 1 month. These showed significant improved retinal function in both waves of approximately 25% but did not reach levels found in 2-month-old animals. Our data suggest, 670 nm light can significantly improve aged retinal function, perhaps by providing additional adenosine triphosphate production for photoreceptor ion pumps or reduced aged inflammation. This may have implications for the treatment of retinal aging and age-related retinal disease, such as macular degeneration.
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Affiliation(s)
| | | | | | - Glen Jeffery
- University College London Institute of Ophthalmology, London, UK.
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Kaynezhad P, Tachtsidis I, Jeffery G. Optical monitoring of retinal respiration in real time: 670 nm light increases the redox state of mitochondria. Exp Eye Res 2016; 152:88-93. [PMID: 27664904 PMCID: PMC5105829 DOI: 10.1016/j.exer.2016.09.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 09/18/2016] [Accepted: 09/20/2016] [Indexed: 02/03/2023]
Abstract
Mitochondria play a key role in ageing and disease. Their membrane potentials and ATP production decline with age and this is associated with progressive inflammation, cell loss and death. Here we use broadband Near-Infrared Spectroscopy (NIRS) to non-invasively measure in-vivo changes in aged retinal mitochondrial respiration following exposure to 670 nm, which improves mitochondrial performance and reduces inflammation. Low power NIR light was shone into the eye via a fibre optic and the reflection monitored to measure signature changes in the oxidation of cytochrome c oxidase (COX) in complex IV of the electron transport chain. Changes in retinal haemodynamics and oxygenation were also recorded simultaneously with COX by measuring changes in oxygenated and deoxygenated haemoglobin (Δ[HbO2] and Δ[HHb]). Retinae of aged rats exposed to 670 nm for 5 mins showed consistent progressive increases in oxidation of COX 5 mins post exposure. This remained significantly greater than baseline for up to 2 h. This was not seen when retinae were exposed to 420 nm light of the same power or when no light was applied. 670 nm exposure significantly increased total haemoglobin concentration (Δ[HbT] = Δ[HbO2] +Δ[HHb]) but not haemoglobin difference (Δ[HbDiff] = Δ[HbO2] -Δ[HHb]). There were no changes in blood metrics in association with 420 nm light or when no light exposure was given. Hence, brief 670 nm exposure that is associated with reduced inflammation has a significant positive impact on the redox state of COX in aged retinae. The relative redox state of retinal COX may provide a valuable biomarker in ageing and macular degeneration where declining mitochondrial function is implicated. We measure real time retinal reflections in vivo in rats. We isolate signals from oxy/deoxy haemoglobin and those from relative COX redox. 670 nm increases COX redox and total haemoglobin improving mitochondrial function. These measurements monitor retinal respiration and may be a biomarker for disease.
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Affiliation(s)
- Pardis Kaynezhad
- Dept of Medical Physics and Biomedical Engineering, University College London, UK
| | - Ilias Tachtsidis
- Dept of Medical Physics and Biomedical Engineering, University College London, UK
| | - Glen Jeffery
- Institute of Ophthalmology, University College London, UK.
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34
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Kam JH, Jeffery G. To unite or divide: mitochondrial dynamics in the murine outer retina that preceded age related photoreceptor loss. Oncotarget 2016; 6:26690-701. [PMID: 26393878 PMCID: PMC4694945 DOI: 10.18632/oncotarget.5614] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 08/27/2015] [Indexed: 12/18/2022] Open
Abstract
Mitochondrial function declines with age and is associated with age-related disorders and cell death. In the retina this is critical as photoreceptor energy demands are the greatest in the body and aged cell loss large (~30%). But mitochondria can fuse or divide to accommodate changing demands. We explore ageing mitochondrial dynamics in young (1 month) and old (12 months) mouse retina, investigating changes in mitochondrial fission (Fis1) and fusion (Opa1) proteins, cytochrome C oxidase (COX III), which reflects mitochondrial metabolic status, and heat shock protein 60 (Hsp60) that is a mitochondrial chaperon for protein folding.Western blots showed each protein declined with age. However, within this, immunostaining revealed increases of around 50% in Fis1 and Opa1 in photoreceptor inner segments (IS). Electron microscope analysis revealed mitochondrial fragmentation with age and marked changes in morphology in IS, consistent with elevated dynamics. COX III declined by approximately 30% in IS, but Hsp60 reductions were around 80% in the outer plexiform layer.Our results are consistent with declining mitochondrial metabolism. But also with increased photoreceptor mitochondrial dynamics that differ from other retinal regions, perhaps reflecting attempts to maintain function. These changes are the platform for age related photoreceptor loss initiated after 12 months.
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Affiliation(s)
- Jaimie Hoh Kam
- Institute of Ophthalmology, University College London, London, UK
| | - Glen Jeffery
- Institute of Ophthalmology, University College London, London, UK
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35
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Beirne K, Rozanowska M, Votruba M. Red Light Treatment in an Axotomy Model of Neurodegeneration. Photochem Photobiol 2016; 92:624-31. [DOI: 10.1111/php.12606] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 05/09/2016] [Indexed: 12/21/2022]
Affiliation(s)
- Kathy Beirne
- School of Optometry and Vision Sciences; Cardiff University; Cardiff UK
- Cardiff Institute for Tissue Engineering and Repair; Cardiff University; Cardiff UK
| | - Malgorzata Rozanowska
- School of Optometry and Vision Sciences; Cardiff University; Cardiff UK
- Cardiff Institute for Tissue Engineering and Repair; Cardiff University; Cardiff UK
| | - Marcela Votruba
- School of Optometry and Vision Sciences; Cardiff University; Cardiff UK
- Cardiff Institute for Tissue Engineering and Repair; Cardiff University; Cardiff UK
- Cardiff Eye Unit; University Hospital of Wales; Cardiff UK
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36
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Aboelnour A, Kam JH, Elnasharty MA, Sayed-Ahmed A, Jeffery G. Amyloid beta deposition and phosphorylated tau accumulation are key features in aged choroidal vessels in the complement factor H knock out model of retinal degeneration. Exp Eye Res 2016; 147:138-143. [PMID: 27181225 DOI: 10.1016/j.exer.2016.05.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 05/11/2016] [Accepted: 05/11/2016] [Indexed: 10/21/2022]
Abstract
Extra-cellular deposition including amyloid beta (Aβ) is a feature of retinal ageing. It has been documented for Bruch's membrane (BM) where Aβ is elevated in complement factor H knockout mice (Cfh(-/-)) proposed as a model for age related macular degeneration. However, arterial deposition in choroidal vessels prior to perfusion across BM has not been examined. Aβ is associated with tau phosphorylation and these are linked in blood vessels in Alzheimers Disease where they can drive perivascular pathology. Here we ask if Aβ, tau and phosphorylated tau are features of ageing in choroidal vessels in 12 month C57 BL/6 and Cfh(-/-) mice, using immune staining and Western blot analysis. Greater levels of Aβ and phosphorylated tau are found in choroidal vessels in Cfh(-/-) mice. Western blot revealed a 40% increase in Aβ in Cfh(-/-) over C57 BL/6 mice. Aβ deposits coat around 55% of the luminal wall in Cfh(-/-) compared to only about 40% in C57 BL/6. Total tau was similar in both groups, but phosphorylated tau increased by >100% in Cfh(-/-) compared to C57 BL/6 and covered >75% of the luminal wall compared to 50% in C57 BL/6. Hence, phosphorylated tau is a marked choroidal feature in this mouse model. Aβ deposition was clumped in Cfh(-/-) mice and likely to influence blood flow dynamics. Disturbed flow is associated with atherogenesis and may be related to the accumulation of membrane attack complex recently identified between choroidal vessels in those at high risk of macular degeneration due to complement factor H polymorphisms.
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Affiliation(s)
- Asmaa Aboelnour
- Histology and Cytology Department, Faculty of Veterinary Medicine, Damanhour University, Egypt
| | - Jaimie Hoh Kam
- Institute of Ophthalmology, University College London, UK
| | - M A Elnasharty
- Histology and Cytology Department, Faculty of Veterinary Medicine, Damanhour University, Egypt
| | - Ahmed Sayed-Ahmed
- Anatomy Department, Faculty of Veterinary Medicine, Damanhour University, Egypt
| | - Glen Jeffery
- Institute of Ophthalmology, University College London, UK.
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Abstract
In diabetes, retinal blood flow is compromised, and retinal hypoxia is likely to be further intensified during periods of darkness. During dark adaptation, rod photoreceptors in the outer retina are maximally depolarized and continuously release large amounts of the neurotransmitter glutamate-an energetically demanding process that requires the highest oxygen consumption per unit volume of any tissue of the body. In complete darkness, even more oxygen is consumed by the outer retina, producing a steep fall in the retinal oxygen tension curve which reaches a nadir at the depth of the mitochondrial-rich rod inner segments. In contrast to the normal retina, the diabetic retina cannot meet the added metabolic load imposed by the dark-adapted rod photoreceptors; this exacerbates retinal hypoxia and stimulates the overproduction of vascular endothelial growth factor (VEGF). The use of nocturnal illumination to prevent dark adaptation, specifically reducing the rod photoreceptor dark current, should ameliorate diabetic retinopathy.
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Affiliation(s)
- David J Ramsey
- Department of Ophthalmology, Lahey Hospital & Medical Center, Tufts University School of Medicine, 41 Mall Road, Burlington, MA, 01805, USA.
| | - G B Arden
- University College London, London, UK.
- Moorfields Eye Hospital NHS Foundation Trust, London, UK.
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