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Roodnat AW, Callaghan B, Doyle C, Vallabh NA, Atkinson SD, Willoughby CE. Genome-wide RNA sequencing of ocular fibroblasts from glaucomatous and normal eyes: Implications for glaucoma management. PLoS One 2024; 19:e0307227. [PMID: 38990974 PMCID: PMC11239048 DOI: 10.1371/journal.pone.0307227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 06/28/2024] [Indexed: 07/13/2024] Open
Abstract
Primary open angle glaucoma is a leading cause of visual impairment and blindness which is commonly treated with drugs or laser but may require surgery. Tenon's ocular fibroblasts are involved in wound-healing after glaucoma filtration surgery and may compromise a favourable outcome of glaucoma surgery by contributing to fibrosis. To investigate changes in gene expression and key pathways contributing to the glaucomatous state we performed genome-wide RNA sequencing. Human Tenon's ocular fibroblasts were cultured from normal and glaucomatous human donors undergoing eye surgery (n = 12). mRNA was extracted and RNA-Seq performed on the Illumina platform. Differentially expressed genes were identified using a bioinformatics pipeline consisting of FastQC, STAR, FeatureCounts and edgeR. Changes in biological functions and pathways were determined using Enrichr and clustered using Cytoscape. A total of 5817 genes were differentially expressed between Tenon's ocular fibroblasts from normal versus glaucomatous eyes. Enrichment analysis showed 787 significantly different biological functions and pathways which were clustered into 176 clusters. Tenon's ocular fibroblasts from glaucomatous eyes showed signs of fibrosis with fibroblast to myofibroblast transdifferentiation and associated changes in mitochondrial fission, remodeling of the extracellular matrix, proliferation, unfolded protein response, inflammation and apoptosis which may relate to the pathogenesis of glaucoma or the detrimental effects of topical glaucoma therapies. Altered gene expression in glaucomatous Tenon's ocular fibroblasts may contribute to an unfavourable outcome of glaucoma filtration surgery. This work presents a genome-wide transcriptome of glaucomatous versus normal Tenon's ocular fibroblasts which may identify genes or pathways of therapeutic value to improve surgical outcomes.
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Affiliation(s)
- Anton W. Roodnat
- Centre for Genomic Medicine, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Breedge Callaghan
- Centre for Genomic Medicine, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Chelsey Doyle
- Centre for Genomic Medicine, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Neeru A. Vallabh
- Department of Eye and Vision Science, Insitute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
- St. Paul’s Eye Unit, Liverpool University Hospital NHS Foundation Trust, Liverpool, United Kingdom
| | - Sarah D. Atkinson
- Centre for Genomic Medicine, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Colin E. Willoughby
- Centre for Genomic Medicine, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, United Kingdom
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Ulhaq ZS, Bittencourt GB, Soraya GV, Istifiani LA, Pamungkas SA, Ogino Y, Nurputra DK, Tse WKF. Association between glaucoma susceptibility with combined defects in mitochondrial oxidative phosphorylation and fatty acid beta oxidation. Mol Aspects Med 2024; 96:101238. [PMID: 38215610 DOI: 10.1016/j.mam.2023.101238] [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: 06/28/2023] [Revised: 11/08/2023] [Accepted: 11/28/2023] [Indexed: 01/14/2024]
Abstract
Glaucoma is one of the leading causes of visual impairment and blindness worldwide, and is characterized by the progressive damage of retinal ganglion cells (RGCs) and the atrophy of the optic nerve head (ONH). The exact cause of RGC loss and optic nerve damage in glaucoma is not fully understood. The high energy demands of these cells imply a higher sensitivity to mitochondrial defects. Moreover, it has been postulated that the optic nerve is vulnerable towards damage from oxidative stress and mitochondrial dysfunction. To investigate this further, we conducted a pooled analysis of mitochondrial variants related to energy production, specifically focusing on oxidative phosphorylation (OXPHOS) and fatty acid β-oxidation (FAO). Our findings revealed that patients carrying non-synonymous (NS) mitochondrial DNA (mtDNA) variants within the OXPHOS complexes had an almost two-fold increased risk of developing glaucoma. Regarding FAO, our results demonstrated that longer-chain acylcarnitines (AC) tended to decrease, while shorter-chain AC tended to increase in patients with glaucoma. Furthermore, we observed that the knocking down cpt1a (a key rate-limiting enzyme involved in FAO) in zebrafish induced a degenerative process in the optic nerve and RGC, which resembled the characteristics observed in glaucoma. In conclusion, our study provides evidence that genes encoding mitochondrial proteins involved in energy metabolisms, such as OXPHOS and FAO, are associated with glaucoma. These findings contribute to a better understanding of the molecular mechanisms underlying glaucoma pathogenesis and may offer potential targets for therapeutic interventions in the future.
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Affiliation(s)
- Zulvikar Syambani Ulhaq
- Research Center for Pre-clinical and Clinical Medicine, National Research and Innovation Agency Republic of Indonesia, Cibinong, Indonesia; Laboratory of Developmental Disorders and Toxicology, Center for Promotion of International Education and Research, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
| | - Guido Barbieri Bittencourt
- Departamento de Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, São Paulo, Brazil
| | - Gita Vita Soraya
- Department of Biochemistry, Faculty of Medicine, Hasanuddin University, Makassar, Indonesia
| | - Lola Ayu Istifiani
- Department of Nutrition, Faculty of Health Sciences, Brawijaya University, Malang, Indonesia
| | | | - Yukiko Ogino
- Laboratory of Aquatic Molecular Developmental Biology, Center for Promotion of International Education and Research, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | | | - William Ka Fai Tse
- Laboratory of Developmental Disorders and Toxicology, Center for Promotion of International Education and Research, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
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Rombaut A, Brautaset R, Williams PA, Tribble JR. Glial metabolic alterations during glaucoma pathogenesis. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1290465. [PMID: 38983068 PMCID: PMC11182098 DOI: 10.3389/fopht.2023.1290465] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 11/10/2023] [Indexed: 07/11/2024]
Abstract
Glaucoma is the leading cause of irreversible blindness. Current treatment options are limited and often only slow disease progression. Metabolic dysfunction has recently been recognized as a key early and persistent mechanism in glaucoma pathophysiology. Several intrinsic metabolic dysfunctions have been identified and treated in retinal ganglion cells to provide neuroprotection. Growing pre-clinical and clinical evidence has confirmed that metabolic alterations in glaucoma are widespread, occurring across visual system tissues, in ocular fluids, in blood/serum, and at the level of genomic and mitochondrial DNA. This suggests that metabolic dysfunction is not constrained to retinal ganglion cells and that metabolic alterations extrinsic to retinal ganglion cells may contribute to their metabolic compromise. Retinal ganglion cells are reliant on glial metabolic support under normal physiological conditions, but the implications of metabolic dysfunction in glia are underexplored. We highlight emerging evidence that has demonstrated metabolic alterations occurring within glia in glaucoma, and how this may affect neuro-glial metabolic coupling and the metabolic vulnerability of retinal ganglion cells. In other neurodegenerative diseases which share features with glaucoma, several other glial metabolic alterations have been identified, suggesting that similar mechanisms and therapeutic targets may exist in glaucoma.
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Affiliation(s)
| | | | - Pete A. Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - James R. Tribble
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
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Stavropoulos D, Grewal MK, Petriti B, Chau KY, Hammond CJ, Garway-Heath DF, Lascaratos G. The Role of Mitophagy in Glaucomatous Neurodegeneration. Cells 2023; 12:1969. [PMID: 37566048 PMCID: PMC10417839 DOI: 10.3390/cells12151969] [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: 06/03/2023] [Revised: 07/15/2023] [Accepted: 07/19/2023] [Indexed: 08/12/2023] Open
Abstract
This review aims to provide a better understanding of the emerging role of mitophagy in glaucomatous neurodegeneration, which is the primary cause of irreversible blindness worldwide. Increasing evidence from genetic and other experimental studies suggests that mitophagy-related genes are implicated in the pathogenesis of glaucoma in various populations. The association between polymorphisms in these genes and increased risk of glaucoma is presented. Reduction in intraocular pressure (IOP) is currently the only modifiable risk factor for glaucoma, while clinical trials highlight the inadequacy of IOP-lowering therapeutic approaches to prevent sight loss in many glaucoma patients. Mitochondrial dysfunction is thought to increase the susceptibility of retinal ganglion cells (RGCs) to other risk factors and is implicated in glaucomatous degeneration. Mitophagy holds a vital role in mitochondrial quality control processes, and the current review explores the mitophagy-related pathways which may be linked to glaucoma and their therapeutic potential.
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Affiliation(s)
- Dimitrios Stavropoulos
- Department of Ophthalmology, King’s College Hospital, London SE5 9RS, UK;
- Department of Ophthalmology, 417 Veterans Army Hospital (NIMTS), 11521 Athens, Greece
| | - Manjot K. Grewal
- NIHR Biomedical Research Center, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Division of Optometry and Visual Science, School of Health Sciences, City, University of London, London EC1V 0HB, UK
| | - Bledi Petriti
- NIHR Biomedical Research Center, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Department of Clinical & Movement Neurosciences, UCL Queens Square Institute of Neurology, London NW3 2PF, UK
| | - Kai-Yin Chau
- Department of Clinical & Movement Neurosciences, UCL Queens Square Institute of Neurology, London NW3 2PF, UK
| | - Christopher J. Hammond
- Section of Ophthalmology, School of Life Course Sciences, King’s College London, London SE1 7EH, UK
- Department of Ophthalmology, St Thomas’ Hospital, London SE1 7EH, UK
| | - David F. Garway-Heath
- NIHR Biomedical Research Center, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - Gerassimos Lascaratos
- Department of Ophthalmology, King’s College Hospital, London SE5 9RS, UK;
- Section of Ophthalmology, School of Life Course Sciences, King’s College London, London SE1 7EH, UK
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Tribble JR, Hagström A, Jusseaume K, Lardner E, Wong RCB, Stålhammar G, Williams PA. NAD salvage pathway machinery expression in normal and glaucomatous retina and optic nerve. Acta Neuropathol Commun 2023; 11:18. [PMID: 36681854 PMCID: PMC9867855 DOI: 10.1186/s40478-023-01513-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 01/10/2023] [Indexed: 01/23/2023] Open
Abstract
Glaucoma is the leading cause of irreversible blindness and is a major health and economic burden. Current treatments do not address the neurodegenerative component of glaucoma. In animal models of glaucoma, the capacity to maintain retinal nicotinamide adenine dinucleotide (NAD) pools declines early during disease pathogenesis. Treatment with nicotinamide, an NAD precursor through the NAD salvage pathway, robustly protects against neurodegeneration in a number of glaucoma models and improves vision in existing glaucoma patients. However, it remains unknown in humans what retinal cell types are able to process nicotinamide to NAD and how these are affected in glaucoma. To address this, we utilized publicly available RNA-sequencing data (bulk, single cell, and single nucleus) and antibody labelling in highly preserved enucleated human eyes to identify expression of NAD synthesizing enzyme machinery. This identifies that the neural retina favors expression of the NAD salvage pathway, and that retinal ganglion cells are particularly enriched for these enzymes. NMNAT2, a key terminal enzyme in the salvage pathway, is predominantly expressed in retinal ganglion cell relevant layers of the retina and declines in glaucoma. These findings suggest that human retinal ganglion cells can directly utilize nicotinamide and could maintain a capacity to do so in glaucoma, showing promise for ongoing clinical trials.
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Affiliation(s)
- James R Tribble
- Division of Eye and Vision, Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Anna Hagström
- Division of Eye and Vision, Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Kenza Jusseaume
- Division of Eye and Vision, Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Emma Lardner
- Division of Eye and Vision, Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Raymond Ching-Bong Wong
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
- Department of Surgery (Ophthalmology), The University of Melbourne, Melbourne, Australia
| | - Gustav Stålhammar
- Division of Eye and Vision, Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Pete A Williams
- Division of Eye and Vision, Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
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