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Hansman D, Ma Y, Thomas D, Smith J, Casson R, Peet D. Metabolic reprogramming of the retinal pigment epithelium by cytokines associated with age-related macular degeneration. Biosci Rep 2024; 44:BSR20231904. [PMID: 38567515 PMCID: PMC11043024 DOI: 10.1042/bsr20231904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 03/17/2024] [Accepted: 04/02/2024] [Indexed: 04/04/2024] Open
Abstract
The complex metabolic relationship between the retinal pigment epithelium (RPE) and photoreceptors is essential for maintaining retinal health. Recent evidence indicates the RPE acts as an adjacent lactate sink, suppressing glycolysis in the epithelium in order to maximize glycolysis in the photoreceptors. Dysregulated metabolism within the RPE has been implicated in the pathogenesis of age-related macular degeneration (AMD), a leading cause of vision loss. In the present study, we investigate the effects of four cytokines associated with AMD, TNFα, TGF-β2, IL-6, and IL-1β, as well as a cocktail containing all four cytokines, on RPE metabolism using ARPE-19 cells, primary human RPE cells, and ex vivo rat eyecups. Strikingly, we found cytokine-specific changes in numerous metabolic markers including lactate production, glucose consumption, extracellular acidification rate, and oxygen consumption rate accompanied by increases in total mitochondrial volume and ATP production. Together, all four cytokines could potently override the constitutive suppression of glycolysis in the RPE, through a mechanism independent of PI3K/AKT, MEK/ERK, or NF-κB. Finally, we observed changes in glycolytic gene expression with cytokine treatment, including in lactate dehydrogenase subunit and glucose transporter expression. Our findings provide new insights into the metabolic changes in the RPE under inflammatory conditions and highlight potential therapeutic targets for AMD.
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Affiliation(s)
- David S. Hansman
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Yuefang Ma
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Daniel Thomas
- South Australian Health and Medical Research Institute (SAHMRI), Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
| | - Justine R. Smith
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Robert J. Casson
- Discipline of Ophthalmology and Visual Science, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
| | - Daniel J. Peet
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
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2
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Rajala A, Rajala RVS. Age-Related Changes in the Glycolytic Enzymes of M2-Isoform of Pyruvate Kinase and Fructose-1,6-Bisphosphate Aldolase: Implications to Age-Related Macular Degeneration. Aging Dis 2024:AD.2024.0077. [PMID: 38739943 DOI: 10.14336/ad.2024.0077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 04/19/2024] [Indexed: 05/16/2024] Open
Abstract
Prior studies have emphasized a bioenergetic crisis in the retinal pigment epithelium (RPE) as a critical factor in the development of age-related macular degeneration (AMD). The isoforms Fructose-1,6-bisphosphate aldolase C (ALDOC) and pyruvate kinase M2 (PKM2) have been proposed to play a role in AMD pathogenesis. While PKM2 and ALDOC are crucial for aerobic glycolysis in the neural retina, they are not as essential for the RPE. In this study, we examined the expression and activity of PKM2 and ALDOC in both young and aged RPE cells, as well as in the retina and RPE tissue of mice, including an experimentally induced AMD mouse model. Our findings reveal an upregulation in PKM2 and ALDOC expression, accompanied by increased pyruvate kinase activity, in the aged and AMD mouse RPE. Conversely, there is a decrease in ALDOC expression but an increase in PKM2 expression and pyruvate kinase activity in the aged and AMD retina. Overall, our study indicates that aged and AMD RPE cells tend to favor aerobic glycolysis, while this tendency is diminished in the aged and AMD retina. These results underscore the significance of targeting PKM2 and ALDOC in the RPE as a promising therapeutic approach to address the bioenergetic crisis and prevent vision loss in AMD.
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Affiliation(s)
- Ammaji Rajala
- Department of Ophthalmology, Oklahoma, Oklahoma 73104, USA
- Dean McGee Eye Institute, Oklahoma, Oklahoma 73104, USA
| | - Raju V S Rajala
- Department of Ophthalmology, Oklahoma, Oklahoma 73104, USA
- Department of Biochemistry and Physiology, and Oklahoma, Oklahoma 73104, USA
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma, Oklahoma 73104, USA
- Dean McGee Eye Institute, Oklahoma, Oklahoma 73104, USA
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3
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Ebrahimi M, Sivaprasad S. The potential effects of newer groups of glucose lowering drugs on age-related macular degeneration. Eye (Lond) 2024:10.1038/s41433-024-03066-5. [PMID: 38605074 DOI: 10.1038/s41433-024-03066-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 03/27/2024] [Accepted: 04/04/2024] [Indexed: 04/13/2024] Open
Affiliation(s)
- Moein Ebrahimi
- School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Network of Immunity in Infection, Malignancy, and Autoimmunity, Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Sobha Sivaprasad
- NIHR Moorfields Biomedical Research Centre, Moorfields Eye Hospital, London, UK.
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4
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Dontsov A, Ostrovsky M. Retinal Pigment Epithelium Pigment Granules: Norms, Age Relations and Pathology. Int J Mol Sci 2024; 25:3609. [PMID: 38612421 PMCID: PMC11011557 DOI: 10.3390/ijms25073609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/14/2024] Open
Abstract
The retinal pigment epithelium (RPE), which ensures the normal functioning of the neural retina, is a pigmented single-cell layer that separates the retina from the Bruch's membrane and the choroid. There are three main types of pigment granules in the RPE cells of the human eye: lipofuscin granules (LG) containing the fluorescent "age pigment" lipofuscin, melanoprotein granules (melanosomes, melanolysosomes) containing the screening pigment melanin and complex melanolipofuscin granules (MLG) containing both types of pigments simultaneously-melanin and lipofuscin. This review examines the functional role of pigment granules in the aging process and in the development of oxidative stress and associated pathologies in RPE cells. The focus is on the process of light-induced oxidative degradation of pigment granules caused by reactive oxygen species. The reasons leading to increased oxidative stress in RPE cells as a result of the oxidative degradation of pigment granules are considered. A mechanism is proposed to explain the phenomenon of age-related decline in melanin content in RPE cells. The essence of the mechanism is that when the lipofuscin part of the melanolipofuscin granule is exposed to light, reactive oxygen species are formed, which destroy the melanin part. As more melanolipofuscin granules are formed with age and the development of degenerative diseases, the melanin in pigmented epithelial cells ultimately disappears.
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Affiliation(s)
| | - Mikhail Ostrovsky
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 119334, Russia;
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5
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Grubaugh CR, Dhingra A, Prakash B, Montenegro D, Sparrow JR, Daniele LL, Curcio CA, Bell BA, Hussain MM, Boesze-Battaglia K. Microsomal triglyceride transfer protein is necessary to maintain lipid homeostasis and retinal function. FASEB J 2024; 38:e23522. [PMID: 38445789 PMCID: PMC10949407 DOI: 10.1096/fj.202302491r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 02/07/2024] [Accepted: 02/16/2024] [Indexed: 03/07/2024]
Abstract
Lipid processing by the retinal pigment epithelium (RPE) is necessary to maintain retinal health and function. Dysregulation of retinal lipid homeostasis due to normal aging or age-related disease triggers lipid accumulation within the RPE, on Bruch's membrane (BrM), and in the subretinal space. In its role as a hub for lipid trafficking into and out of the neural retina, the RPE packages a significant amount of lipid into lipid droplets for storage and into apolipoprotein B (APOB)-containing lipoproteins (Blps) for export. Microsomal triglyceride transfer protein (MTP), encoded by the MTTP gene, is essential for Blp assembly. Herein we test the hypothesis that MTP expression in the RPE is essential to maintain lipid balance and retinal function using the newly generated RPEΔMttp mouse model. Using non-invasive ocular imaging, electroretinography, and histochemical and biochemical analyses we show that genetic depletion of Mttp from the RPE results in intracellular lipid accumulation, increased photoreceptor-associated cholesterol deposits, and photoreceptor cell death, and loss of rod but not cone function. RPE-specific reduction in Mttp had no significant effect on plasma lipids and lipoproteins. While APOB was decreased in the RPE, most ocular retinoids remained unchanged, with the exception of the storage form of retinoid, retinyl ester. Thus suggesting that RPE MTP is critical for Blp synthesis and assembly but is not directly involved in plasma lipoprotein metabolism. These studies demonstrate that RPE-specific MTP expression is necessary to establish and maintain retinal lipid homeostasis and visual function.
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Affiliation(s)
- Catharina R. Grubaugh
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anuradha Dhingra
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Binu Prakash
- Department of Foundations of Medicine, New York University Grossman Long Island School of Medicine, Mineola, NY, 11501 USA
| | - Diego Montenegro
- Department of Ophthalmology and Department of Pathology and Cell Biology, Columbia University, New York, NY, 10027 USA
| | - Janet R. Sparrow
- Department of Ophthalmology and Department of Pathology and Cell Biology, Columbia University, New York, NY, 10027 USA
| | - Lauren L. Daniele
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Brent A. Bell
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104 USA
| | - M. Mahmood Hussain
- Department of Foundations of Medicine, New York University Grossman Long Island School of Medicine, Mineola, NY, 11501 USA
| | - Kathleen Boesze-Battaglia
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
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6
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Saeedi-Maleki Z, Javadzadeh A, Brumandpur F, Ghorbanihaghjo A, Khanzadeh S, Mousavi F. Serum adropin level in wet-type age-related macular degeneration. Int J Retina Vitreous 2024; 10:27. [PMID: 38475838 DOI: 10.1186/s40942-024-00543-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 02/13/2024] [Indexed: 03/14/2024] Open
Abstract
PURPOSE Our objective was to compare the serum Adropin levels between patients with wet-type Age-Related Macular Degeneration (AMD) and otherwise healthy individuals. METHOD The study included 45 patients with wet-type AMD and 45 individuals without age-related macular degeneration. Patients with co-morbidities such as diabetes, hypertension, autoimmune diseases, and a previous history of visual impairment; were excluded. FBS, Hemoglobin A1C (HbA1C), lipid profile, and serum Adropin level were checked. RESULTS The mean serum Adropin level of patients with wet-type AMD was significantly lower than the control group (P-value < 0.001). Also, the mean High-sensitivity C-reactive protein ( hsCRP) level and High Density Lipoprotein (HDL) were significantly higher in wet-type AMD patients (P-value = 0.031 and < 0.001 respectively). CONCLUSIONS In our study, wet-type AMD was associated with a lower level of serum Adropin. Because of Adropin involvement in glucose metabolism and age-related changes, it may have a role in the pathogenesis of AMD, but it requires more investigations at the molecular level to elucidate its function.
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Affiliation(s)
- Zahra Saeedi-Maleki
- Department of Ophthalmology, Tabriz University of Medical Sciences, Tabriz, Iran
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Alireza Javadzadeh
- Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Fariborz Brumandpur
- Department of Ophthalmology, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Amir Ghorbanihaghjo
- Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Farideh Mousavi
- Department of Ophthalmology, Tabriz University of Medical Sciences, Tabriz, Iran.
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7
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Chen B, Zou J, Xie L, Cai Y, Li B, Tan W, Huang J, Li F, Xu H. WNT-inhibitory factor 1-mediated glycolysis protects photoreceptor cells in diabetic retinopathy. J Transl Med 2024; 22:245. [PMID: 38448948 PMCID: PMC10918886 DOI: 10.1186/s12967-024-05046-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 02/28/2024] [Indexed: 03/08/2024] Open
Abstract
BACKGROUND In diabetic retinopathy (DR), hypoxia-inducible factor (HIF-1α) induces oxidative stress by upregulating glycolysis. This process leads to neurodegeneration, particularly photoreceptor cell damage, which further contributes to retinal microvascular deterioration. Further, the regulation of Wnt-inhibitory factor 1 (WIF1), a secreted Wnt signaling antagonist, has not been fully characterized in neurodegenerative eye diseases. We aimed to explore the impact of WIF1 on photoreceptor function within the context of DR. METHOD Twelve-week-old C57BL/KsJ-db/db mice were intravitreally injected with WIF1 overexpression lentivirus. After 4 weeks, optical coherence tomography (OCT), transmission electron microscopy (TEM), H&E staining, and electroretinography (ERG) were used to assess the retinal tissue and function. The potential mechanism of action of WIF1 in photoreceptor cells was explored using single-cell RNA sequencing. Under high-glucose conditions, 661 W cells were used as an in vitro DR model. WIF1-mediated signaling pathway components were assessed using quantitative real-time PCR, immunostaining, and western blotting. RESULT Typical diabetic manifestations were observed in db/db mice. Notably, the expression of WIF1 was decreased at the mRNA and protein levels. These pathological manifestations and visual function improved after WIF1 overexpression in db/db mice. TEM demonstrated that WIF1 restored damaged mitochondria, the Golgi apparatus, and photoreceptor outer segments. Moreover, ERG indicated the recovery of a-wave potential amplitude. Single-cell RNA sequencing and in vitro experiments suggested that WIF1 overexpression prevented the expression of glycolytic enzymes and lactate production by inhibiting the canonical Wnt signaling pathway, HIF-1α, and Glut1, thereby reducing retinal and cellular reactive oxygen species levels and maintaining 661 W cell viability. CONCLUSIONS WIF1 exerts an inhibitory effect on the Wnt/β-catenin-HIF-1α-Glut1 glycolytic pathway, thereby alleviating oxidative stress levels and mitigating pathological structural characteristics in retinal photoreceptor cells. This mechanism helps preserve the function of photoreceptor cells in DR and indicates that WIF1 holds promise as a potential therapeutic candidate for DR and other neurodegenerative ocular disorders.
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Affiliation(s)
- Bolin Chen
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Central South University, No 87, Xiangya Road, Kaifu District, Changsha, 410008, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Jing Zou
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Central South University, No 87, Xiangya Road, Kaifu District, Changsha, 410008, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Lihui Xie
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Central South University, No 87, Xiangya Road, Kaifu District, Changsha, 410008, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Yinjun Cai
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Central South University, No 87, Xiangya Road, Kaifu District, Changsha, 410008, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Bowen Li
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Central South University, No 87, Xiangya Road, Kaifu District, Changsha, 410008, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Wei Tan
- Department of Ophthalmology, Xiangtan Central Hospital, Xiangtan, 411199, Hunan, China
| | - Jinhaohao Huang
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Central South University, No 87, Xiangya Road, Kaifu District, Changsha, 410008, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Fangling Li
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Central South University, No 87, Xiangya Road, Kaifu District, Changsha, 410008, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Huizhuo Xu
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Central South University, No 87, Xiangya Road, Kaifu District, Changsha, 410008, Hunan, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
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8
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Shen T, Lin R, Hu C, Yu D, Ren C, Li T, Zhu M, Wan Z, Su T, Wu Y, Cai W, Yu J. Succinate-induced macrophage polarization and RBP4 secretion promote vascular sprouting in ocular neovascularization. J Neuroinflammation 2023; 20:308. [PMID: 38129891 PMCID: PMC10734053 DOI: 10.1186/s12974-023-02998-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023] Open
Abstract
Pathological neovascularization is a pivotal biological process in wet age-related macular degeneration (AMD), retinopathy of prematurity (ROP) and proliferative diabetic retinopathy (PDR), in which macrophages (Mφs) play a key role. Tip cell specialization is critical in angiogenesis; however, its interconnection with the surrounding immune environment remains unclear. Succinate is an intermediate in the tricarboxylic acid (TCA) cycle and was significantly elevated in patients with wet AMD by metabolomics. Advanced experiments revealed that SUCNR1 expression in Mφ and M2 polarization was detected in abnormal vessels of choroidal neovascularization (CNV) and oxygen-induced retinopathy (OIR) models. Succinate-induced M2 polarization via SUCNR1, which facilitated vascular endothelial cell (EC) migration, invasion, and tubulation, thus promoting angiogenesis in pathological neovascularization. Furthermore, evidence indicated that succinate triggered the release of RBP4 from Mφs into the surroundings to regulate endothelial sprouting and pathological angiogenesis via VEGFR2, a marker of tip cell formation. In conclusion, our results suggest that succinate represents a novel class of vasculature-inducing factors that modulate Mφ polarization and the RBP4/VEGFR2 pathway to induce pathological angiogenic signaling through tip cell specialization.
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Affiliation(s)
- Tianyi Shen
- Department of Ophthalmology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Ruoyi Lin
- Department of Ophthalmology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Chengyu Hu
- Department of Ophthalmology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Donghui Yu
- Department of Ophthalmology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Chengda Ren
- Department of Ophthalmology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Tingting Li
- Department of Ophthalmology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Meijiang Zhu
- Department of Ophthalmology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Zhongqi Wan
- Department of Ophthalmology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Tu Su
- Department of Ophthalmology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Yan Wu
- Department of Ophthalmology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China.
| | - Wenting Cai
- Department of Ophthalmology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China.
| | - Jing Yu
- Department of Ophthalmology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China.
- Department of Ophthalmology, The Third People's Hospital of Bengbu, Bengbu, China.
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9
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Babapoor-Farrokhran S, Qin Y, Flores-Bellver M, Niu Y, Bhutto IA, Aparicio-Domingo S, Guo C, Rodrigues M, Domashevich T, Deshpande M, Megarity H, Chopde R, Eberhart CG, Canto-Soler V, Montaner S, Sodhi A. Pathologic vs. protective roles of hypoxia-inducible factor 1 in RPE and photoreceptors in wet vs. dry age-related macular degeneration. Proc Natl Acad Sci U S A 2023; 120:e2302845120. [PMID: 38055741 PMCID: PMC10723156 DOI: 10.1073/pnas.2302845120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 09/20/2023] [Indexed: 12/08/2023] Open
Abstract
It has previously been reported that antioxidant vitamins can help reduce the risk of vision loss associated with progression to advanced age-related macular degeneration (AMD), a leading cause of visual impairment among the elderly. Nonetheless, how oxidative stress contributes to the development of choroidal neovascularization (CNV) in some AMD patients and geographic atrophy (GA) in others is poorly understood. Here, we provide evidence demonstrating that oxidative stress cooperates with hypoxia to synergistically stimulate the accumulation of hypoxia-inducible factor (HIF)-1α in the retinal pigment epithelium (RPE), resulting in increased expression of the HIF-1-dependent angiogenic mediators that promote CNV. HIF-1 inhibition blocked the expression of these angiogenic mediators and prevented CNV development in an animal model of ocular oxidative stress, demonstrating the pathological role of HIF-1 in response to oxidative stress stimulation in neovascular AMD. While human-induced pluripotent stem cell (hiPSC)-derived RPE monolayers exposed to chemical oxidants resulted in disorganization and disruption of their normal architecture, RPE cells proved remarkably resistant to oxidative stress. Conversely, equivalent doses of chemical oxidants resulted in apoptosis of hiPSC-derived retinal photoreceptors. Pharmacologic inhibition of HIF-1 in the mouse retina enhanced-while HIF-1 augmentation reduced-photoreceptor apoptosis in two mouse models for oxidative stress, consistent with a protective role for HIF-1 in photoreceptors in patients with advanced dry AMD. Collectively, these results suggest that in patients with AMD, increased expression of HIF-1α in RPE exposed to oxidative stress promotes the development of CNV, but inadequate HIF-1α expression in photoreceptors contributes to the development of GA.
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Affiliation(s)
| | - Yu Qin
- Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD21287
- Department of Ophthalmology, The Fourth Affiliated Hospital of China Medical University, Shenyang110005, China
- Department of Ophthalmology, Eye Hospital of China Medical University, Shenyang110005, China
- Key Lens Research Laboratory of Liaoning Province, Shenyang110005, China
| | - Miguel Flores-Bellver
- CellSight Ocular Stem Cell and Regeneration Research Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado School of Medicine, Aurora, CO80045
| | - Yueqi Niu
- Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD21287
| | - Imran A. Bhutto
- Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD21287
| | - Silvia Aparicio-Domingo
- CellSight Ocular Stem Cell and Regeneration Research Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado School of Medicine, Aurora, CO80045
| | - Chuanyu Guo
- Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD21287
| | - Murilo Rodrigues
- Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD21287
| | - Timothy Domashevich
- CellSight Ocular Stem Cell and Regeneration Research Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado School of Medicine, Aurora, CO80045
| | - Monika Deshpande
- Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD21287
| | - Haley Megarity
- Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD21287
| | - Rakesh Chopde
- Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD21287
| | - Charles G. Eberhart
- Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD21287
| | - Valeria Canto-Soler
- CellSight Ocular Stem Cell and Regeneration Research Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado School of Medicine, Aurora, CO80045
| | - Silvia Montaner
- Department of Oncology and Diagnostic Sciences, Greenebaum Cancer Center, University of Maryland, Baltimore, MD21201
| | - Akrit Sodhi
- Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD21287
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10
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Grubaugh CR, Dhingra A, Prakash B, Montenegro D, Sparrow JR, Daniele LL, Curcio CA, Bell BA, Hussain MM, Boesze-Battaglia K. Microsomal triglyceride transfer protein is necessary to maintain lipid homeostasis and retinal function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.06.570418. [PMID: 38105975 PMCID: PMC10723417 DOI: 10.1101/2023.12.06.570418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Lipid processing by the retinal pigment epithelium (RPE) is necessary to maintain retinal health and function. Dysregulation of retinal lipid homeostasis due to normal aging or to age-related disease triggers lipid accumulation within the RPE, on Bruch's membrane (BrM), and in the subretinal space. In its role as a hub for lipid trafficking into and out of the neural retina, the RPE packages a significant amount of lipid into lipid droplets for storage and into apolipoprotein B (apoB)-containing lipoproteins (Blps) for export. Microsomal triglyceride transfer protein (MTP), encoded by the MTTP gene, is essential for Blp assembly. Herein we test the hypothesis that MTP expression in the RPE is essential to maintain lipid balance and retinal function using the newly generated RPEΔMttp mouse model. Using non-invasive ocular imaging, electroretinography, and histochemical and biochemical analyses we show that genetic deletion of Mttp from the RPE results in intracellular lipid accumulation, increased photoreceptor -associated cholesterol deposits and photoreceptor cell death, and loss of rod but not cone function. RPE-specific ablation of Mttp had no significant effect on plasma lipids and lipoproteins. While, apoB was decreased in the RPE, ocular retinoid concentrations remained unchanged. Thus suggesting that RPE MTP is critical for Blp synthesis and assembly but not directly involved in ocular retinoid and plasma lipoprotein metabolism. These studies demonstrate that RPE-specific MTP expression is necessary to establish and maintain retinal lipid homeostasis and visual function.
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Affiliation(s)
- Catharina R. Grubaugh
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anuradha Dhingra
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Binu Prakash
- Department of Foundations of Medicine, New York University Grossman Long Island School of Medicine, Mineola, NY, 11501 USA
| | - Diego Montenegro
- Department of Ophthalmology and Department of Pathology and Cell Biology, Columbia University, New York, NY,10027 USA
| | - Janet R. Sparrow
- Department of Ophthalmology and Department of Pathology and Cell Biology, Columbia University, New York, NY,10027 USA
| | - Lauren L. Daniele
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Brent A. Bell
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104 USA
| | - M. Mahmood Hussain
- Department of Foundations of Medicine, New York University Grossman Long Island School of Medicine, Mineola, NY, 11501 USA
| | - Kathleen Boesze-Battaglia
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
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11
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Rajala RVS, Rajala A. Unlocking the role of lactate: metabolic pathways, signaling, and gene regulation in postmitotic retinal cells. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1296624. [PMID: 38983010 PMCID: PMC11182115 DOI: 10.3389/fopht.2023.1296624] [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: 09/18/2023] [Accepted: 10/19/2023] [Indexed: 07/11/2024]
Abstract
The Warburg effect, which was first described a century ago, asserts that mitotic tumor cells generate higher quantities of lactate. Intriguingly, even in typical physiological circumstances, postmitotic retinal photoreceptor cells also produce elevated levels of lactate. Initially classified as metabolic waste, lactate has since gained recognition as a significant intracellular signaling mediator and extracellular ligand. This current review endeavors to provide a concise overview and discourse on the following topics: the localization of lactate-producing enzymes, the functional significance of these enzymes, the signaling functions of lactate, and its impact on the gene expression of photoreceptors in retinal cells.
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Affiliation(s)
- Raju V. S. Rajala
- Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Departments of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Departments of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Dean McGee Eye Institute, Oklahoma City, OK, United States
| | - Ammaji Rajala
- Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Dean McGee Eye Institute, Oklahoma City, OK, United States
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12
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Cheng J, Keuthan CJ, Esumi N. The many faces of SIRT6 in the retina and retinal pigment epithelium. Front Cell Dev Biol 2023; 11:1244765. [PMID: 38016059 PMCID: PMC10646311 DOI: 10.3389/fcell.2023.1244765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 10/18/2023] [Indexed: 11/30/2023] Open
Abstract
Sirtuin 6 (SIRT6) is a member of the mammalian sirtuin family of NAD+-dependent protein deacylases, homologues of the yeast silent information regulator 2 (Sir2). SIRT6 has remarkably diverse functions and plays a key role in a variety of biological processes for maintaining cellular and organismal homeostasis. In this review, our primary aim is to summarize recent progress in understanding SIRT6's functions in the retina and retinal pigment epithelium (RPE), with the hope of further drawing interests in SIRT6 to increase efforts in exploring the therapeutic potential of this unique protein in the vision field. Before describing SIRT6's role in the eye, we first discuss SIRT6's general functions in a wide range of biological contexts. SIRT6 plays an important role in gene silencing, metabolism, DNA repair, antioxidant defense, inflammation, aging and longevity, early development, and stress response. In addition, recent studies have revealed SIRT6's role in macrophage polarization and mitochondrial homeostasis. Despite being initially understudied in the context of the eye, recent efforts have begun to elucidate the critical functions of SIRT6 in the retina and RPE. In the retina, SIRT6 is essential for adult retinal function, regulates energy metabolism by suppressing glycolysis that affects photoreceptor cell survival, protects retinal ganglion cells from oxidative stress, and plays a role in Müller cells during early neurodegenerative events in diabetic retinopathy. In the RPE, SIRT6 activates autophagy in culture and protects against oxidative stress in mice. Taken together, this review demonstrates that better understanding of SIRT6's functions and their mechanisms, both in and out of the context of the eye, holds great promise for the development of SIRT6-targeted strategies for prevention and treatment of blinding eye diseases.
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Affiliation(s)
| | | | - Noriko Esumi
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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13
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Henning Y, Willbrand K, Larafa S, Weißenberg G, Matschke V, Theiss C, Görtz GE, Matschke J. Cigarette smoke causes a bioenergetic crisis in RPE cells involving the downregulation of HIF-1α under normoxia. Cell Death Discov 2023; 9:398. [PMID: 37880219 PMCID: PMC10600121 DOI: 10.1038/s41420-023-01695-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/03/2023] [Accepted: 10/16/2023] [Indexed: 10/27/2023] Open
Abstract
Age-related macular degeneration (AMD) is the most common blinding disease in the elderly population. However, there are still many uncertainties regarding the pathophysiology at the molecular level. Currently, impaired energy metabolism in retinal pigment epithelium (RPE) cells is discussed as one major hallmark of early AMD pathophysiology. Hypoxia-inducible factors (HIFs) are important modulators of mitochondrial function. Moreover, smoking is the most important modifiable risk factor for AMD and is known to impair mitochondrial integrity. Therefore, our aim was to establish a cell-based assay that enables us to investigate how smoking affects mitochondrial function in conjunction with HIF signaling in RPE cells. For this purpose, we treated a human RPE cell line with cigarette smoke extract (CSE) under normoxia (21% O2), hypoxia (1% O2), or by co-treatment with Roxadustat, a clinically approved HIF stabilizer. CSE treatment impaired mitochondrial integrity, involving increased mitochondrial reactive oxygen species, disruption of mitochondrial membrane potential, and altered mitochondrial morphology. Treatment effects on cell metabolism were analyzed using a Seahorse Bioanalyzer. Mitochondrial respiration and ATP production were impaired in CSE-treated cells under normoxia. Surprisingly, CSE-treated RPE cells also exhibited decreased glycolytic rate under normoxia, causing a bioenergetic crisis, because two major metabolic pathways that provide ATP were impaired by CSE. Downregulation of glycolytic rate was HIF-dependent because HIF-1α, the α-subunit of HIF-1, was downregulated by CSE on the protein level, especially under normoxia. Moreover, hypoxia incubation and treatment with Roxadustat restored glycolytic flux. Taken together, our in vitro model provides interesting insights into HIF-dependent regulation of glycolysis under normoxic conditions, which will enable us to investigate signaling pathways involved in RPE metabolism in health and disease.
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Affiliation(s)
- Yoshiyuki Henning
- Institute of Physiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
| | - Katrin Willbrand
- Institute of Physiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Safa Larafa
- Institute of Cell Biology (Cancer Research), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Gesa Weißenberg
- Institute of Physiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Veronika Matschke
- Department of Cytology, Institute of Anatomy, Ruhr University Bochum, Bochum, Germany
| | - Carsten Theiss
- Department of Cytology, Institute of Anatomy, Ruhr University Bochum, Bochum, Germany
| | - Gina-Eva Görtz
- Molecular Ophthalmology, Department of Ophthalmology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Johann Matschke
- Institute of Cell Biology (Cancer Research), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
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14
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Dobreva A, Camacho ET, Miranda M. Mathematical model for glutathione dynamics in the retina. Sci Rep 2023; 13:10996. [PMID: 37419948 PMCID: PMC10328985 DOI: 10.1038/s41598-023-37938-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 06/29/2023] [Indexed: 07/09/2023] Open
Abstract
The retina is highly susceptible to the generation of toxic reactive oxygen species (ROS) that disrupt the normal operations of retinal cells. The glutathione (GSH) antioxidant system plays an important role in mitigating ROS. To perform its protective functions, GSH depends on nicotinamide adenine dinucleotide phosphate (NADPH) produced through the pentose phosphate pathway. This work develops the first mathematical model for the GSH antioxidant system in the outer retina, capturing the most essential components for formation of ROS, GSH production, its oxidation in detoxifying ROS, and subsequent reduction by NADPH. We calibrate and validate the model using experimental measurements, at different postnatal days up to PN28, from control mice and from the rd1 mouse model for the disease retinitis pigmentosa (RP). Global sensitivity analysis is then applied to examine the model behavior and identify the pathways with the greatest impact in control compared to RP conditions. The findings underscore the importance of GSH and NADPH production in dealing with oxidative stress during retinal development, especially after peak rod degeneration occurs in RP, leading to increased oxygen tension. This suggests that stimulation of GSH and NADPH synthesis could be a potential intervention strategy in degenerative mouse retinas with RP.
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Affiliation(s)
- Atanaska Dobreva
- Department of Mathematics, Augusta University, Augusta, GA, 30912, USA.
| | - Erika Tatiana Camacho
- University of Texas at San Antonio, San Antonio, TX, 78249, USA
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, 85281, USA
| | - María Miranda
- Department of Biomedical Sciences, Faculty of Health Sciences, Institute of Biomedical Sciences, Cardenal Herrera-CEU University, CEU Universities, 46115, Valencia, Spain
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15
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Dhingra A, Tobias JW, Philp NJ, Boesze-Battaglia K. Transcriptomic Changes Predict Metabolic Alterations in LC3 Associated Phagocytosis in Aged Mice. Int J Mol Sci 2023; 24:6716. [PMID: 37047689 PMCID: PMC10095460 DOI: 10.3390/ijms24076716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/28/2023] [Accepted: 03/28/2023] [Indexed: 04/14/2023] Open
Abstract
LC3b (Map1lc3b) plays an essential role in canonical autophagy and is one of several components of the autophagy machinery that mediates non-canonical autophagic functions. Phagosomes are often associated with lipidated LC3b to promote phagosome maturation in a process called LC3-associated phagocytosis (LAP). Specialized phagocytes, such as mammary epithelial cells, retinal pigment epithelial (RPE) cells, and sertoli cells, utilize LAP for optimal degradation of phagocytosed material, including debris. In the visual system, LAP is critical to maintain retinal function, lipid homeostasis, and neuroprotection. In a mouse model of retinal lipid steatosis-mice lacking LC3b (LC3b-/-), we observed increased lipid deposition, metabolic dysregulation, and enhanced inflammation. Herein, we present a non-biased approach to determine if loss of LAP mediated processes modulate the expression of various genes related to metabolic homeostasis, lipid handling, and inflammation. A comparison of the RPE transcriptome of WT and LC3b-/- mice revealed 1533 DEGs, with ~73% upregulated and 27% downregulated. Enriched gene ontology (GO) terms included inflammatory response (upregulated DEGs), fatty acid metabolism, and vascular transport (downregulated DEGs). Gene set enrichment analysis (GSEA) identified 34 pathways; 28 were upregulated (dominated by inflammation/related pathways) and 6 were downregulated (dominated by metabolic pathways). Analysis of additional gene families identified significant differences for genes in the solute carrier family, RPE signature genes, and genes with a potential role in age-related macular degeneration. These data indicate that loss of LC3b induces robust changes in the RPE transcriptome contributing to lipid dysregulation and metabolic imbalance, RPE atrophy, inflammation, and disease pathophysiology.
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Affiliation(s)
- Anuradha Dhingra
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - John W. Tobias
- Penn Genomics and Sequencing Core, Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nancy J. Philp
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Kathleen Boesze-Battaglia
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
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16
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Activation of Nrf2/HO-1 antioxidant signaling correlates with the preventive effect of loganin on oxidative injury in ARPE-19 human retinal pigment epithelial cells. Genes Genomics 2023; 45:271-284. [PMID: 36018494 DOI: 10.1007/s13258-022-01302-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 08/03/2022] [Indexed: 11/04/2022]
Abstract
BACKGROUND Loganin, a type of iridoid glycoside derived from Corni Fructus, is known to have beneficial effects various chronic diseases. However, studies on mechanisms related to antioxidant efficacy in human retinal pigment epithelial (RPE) cells have not yet been conducted. OBJECTIVES This study was to investigate whether loganin could inhibit oxidative stress-mediated cellular damage caused by hydrogen peroxide (H2O2) in human RPE ARPE-19 cells. METHODS The preventive effect of loganin on H2O2-induced cytotoxicity, reactive oxygen species (ROS) generation, DNA damage and apoptosis was investigated. In addition, immunofluorescence staining and immunoblotting analysis were applied to evaluate the related mechanisms. RESULTS The loss of cell viability and increased ROS accumulation in H2O2-treated ARPE-19 cells were significantly abrogated by loganin pretreatment, which was associated with activation of nuclear factor erythroid 2-related factor 2 (Nrf2) and increased expression of heme oxygenase-1 (HO-1). Loganin also markedly attenuated H2O2-induced DNA damage, ultimately ameliorating apoptosis. In addition, H2O2-induced mitochondrial dysfunction was reversed in the presence of loganin as indicated by preservation of mitochondrial integrity, decrease of Bax/Bcl-2 expression ratio, reduction of caspase-3 activity and suppression of cytochrome c release into the cytoplasm. However, zinc protoporphyrin, a selective inhibitor of HO-1, remarkably alleviated the preventive effect offered by loganin against H2O2-mediated ARPE-19 cell injury, suggesting a critical role of Nrf2-mediated activation of HO-1 in the antioxidant activity of loganin. CONCLUSION The results of this study suggest that loganin-induced activation of the Nrf2/HO-1 axis is at least involved in protecting at least ARPE-19 cells from oxidative injury.
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17
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A 3-miRNA Risk Scoring Signature in Early Diabetic Retinopathy. J Clin Med 2023; 12:jcm12051777. [PMID: 36902565 PMCID: PMC10003264 DOI: 10.3390/jcm12051777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/17/2023] [Accepted: 02/09/2023] [Indexed: 02/25/2023] Open
Abstract
PURPOSE The aim of our study was to investigate a comprehensive profile of streptozotocin (STZ)-induced early diabetic retinopathy (DR) mice to identify a risk scoring signature based on micorRNAs (miRNAs) for early DR diagnosis. METHODS RNA sequencing was performed to obtain the gene expression profile of retinal pigment epithelium (RPE) in early STZ-induced mice. Differentially expressed genes (DEGs) were determined with log2|fold change (FC)| > 1 and p value < 0.05. Functional analysis was carried out based on gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis and the protein-protein interaction (PPI) network. We predicted the potential miRNAs via online tools and ROC curves were then conducted. Three potential miRNAs with AUC > 0.7 were explored via public datasets and a formula was further established to evaluate DR severity. RESULTS In total, 298 DEGs (200 up-regulating and 98 down-regulating) were obtained through RNA sequencing. Hsa-miR-26a-5p, hsa-miR-129-2-3p and hsa-miR-217 were three predicted miRNAs with AUC > 0.7, suggesting their potential to distinguish healthy controls from early DR. The formula of DR severity score = 19.257 - 0.004 × hsa-miR-217 + 5.09 × 10-5 × hsa-miR-26a-5p - 0.003 × hsa-miR-129-2-3p was established based on regression analysis. CONCLUSIONS In the present study, we investigated the candidate genes and molecular mechanisms based on RPE sequencing in early DR mice models. Hsa-miR-26a-5p, hsa-miR-129-2-3p and hsa-miR-217 could work as biomarkers for early DR diagnosis and DR severity prediction, which was beneficial for DR early intervention and treatment.
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18
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A local source of insulin protects the retina against starvation. Nat Metab 2023; 5:205-206. [PMID: 36732625 DOI: 10.1038/s42255-023-00745-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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19
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Tian H, Zhao L, Li H, Huang Y, Wang Y. Circular RNA in Retina: A Potential Biomarker and Therapeutic Target. Ophthalmic Res 2023; 66:516-528. [PMID: 36689924 DOI: 10.1159/000529207] [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: 05/12/2022] [Accepted: 01/09/2023] [Indexed: 01/24/2023]
Abstract
Circular RNA (circRNA) is a newly discovered noncoding RNA, which forms a closed ring with more than 200 bases in length. CircRNA is formed by back splicing of precursor RNA, and its expression abundance in body fluid is up to 10 times that of homologous linear transcripts. Recently, novel activities for circRNA in various diseases have emerged, ranging from cancer therapy and neurodegenerative diseases. Here, we reviewed the literature on the biogenesis of circRNA and its relationship with retinal diseases in recent years. We first described the mechanism, existing form and main function of circRNA. Next, we also pinpoint that circRNA has great value in the diagnosis and treatment of retinal diseases represented by retinoblastoma, retinal degeneration, and diabetic retinopathy. By this review, we hope to explore more possibilities of circRNA in clinical diagnosis and treatment.
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Affiliation(s)
- Huiwen Tian
- Department of Ophthalmology, Beijing Friendship Hospital, Capital Medical University, Beijing, China,
| | - Lu Zhao
- Department of Ophthalmology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Hongyang Li
- Department of Ophthalmology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Yingxiang Huang
- Department of Ophthalmology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Yanling Wang
- Department of Ophthalmology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
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20
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Hong SH, Park C, Hwangbo H, Bang E, Kim SO, Shim JH, Park SH, Lee H, Leem SH, Kim GY, Choi YH. Activation of Heme Oxygenase-1 is Involved in the Preventive Effect of Honokiol against Oxidative Damage in Human Retinal Pigment Epithelial Cells. BIOTECHNOL BIOPROC E 2022. [DOI: 10.1007/s12257-022-0174-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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21
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Wong JHC, Ma JYW, Jobling AI, Brandli A, Greferath U, Fletcher EL, Vessey KA. Exploring the pathogenesis of age-related macular degeneration: A review of the interplay between retinal pigment epithelium dysfunction and the innate immune system. Front Neurosci 2022; 16:1009599. [PMID: 36408381 PMCID: PMC9670140 DOI: 10.3389/fnins.2022.1009599] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/12/2022] [Indexed: 07/30/2023] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss in the older population. Classical hallmarks of early and intermediate AMD are accumulation of drusen, a waste deposit formed under the retina, and pigmentary abnormalities in the retinal pigment epithelium (RPE). When the disease progresses into late AMD, vision is affected due to death of the RPE and the light-sensitive photoreceptors. The RPE is essential to the health of the retina as it forms the outer blood retinal barrier, which establishes ocular immune regulation, and provides support for the photoreceptors. Due to its unique anatomical position, the RPE can communicate with the retinal environment and the systemic immune environment. In AMD, RPE dysfunction and the accumulation of drusen drive the infiltration of retinal and systemic innate immune cells into the outer retina. While recruited endogenous or systemic mononuclear phagocytes (MPs) contribute to the removal of noxious debris, the accumulation of MPs can also result in chronic inflammation and contribute to AMD progression. In addition, direct communication and indirect molecular signaling between MPs and the RPE may promote RPE cell death, choroidal neovascularization and fibrotic scarring that occur in late AMD. In this review, we explore how the RPE and innate immune cells maintain retinal homeostasis, and detail how RPE dysfunction and aberrant immune cell recruitment contribute to AMD pathogenesis. Evidence from AMD patients will be discussed in conjunction with data from preclinical models, to shed light on future therapeutic targets for the treatment of AMD.
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22
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Ren X, Léveillard T. Modulating antioxidant systems as a therapeutic approach to retinal degeneration. Redox Biol 2022; 57:102510. [PMID: 36274523 PMCID: PMC9596747 DOI: 10.1016/j.redox.2022.102510] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/11/2022] [Accepted: 10/11/2022] [Indexed: 11/21/2022] Open
Abstract
The human retina is facing a big challenge of reactive oxygen species (ROS) from endogenous and exogenous sources. Excessive ROS can cause damage to DNA, lipids, and proteins, triggering abnormal redox signaling, and ultimately lead to cell death. Thus, oxidative stress has been observed in inherited retinal diseases as a common hallmark. To counteract the detrimental effect of ROS, cells are equipped with various antioxidant defenses. In this review, we will focus on the antioxidant systems in the retina and how they can protect retina from oxidative stress. Both small antioxidants and antioxidant enzymes play a role in ROS removal. Particularly, the thioredoxin and glutaredoxin systems, as the major antioxidant systems in mammalian cells, exert functions in redox signaling regulation via modifying cysteines in proteins. In addition, the thioredoxin-like rod-derived cone viability factor (RdCVFL) and thioredoxin interacting protein (TXNIP) can modulate metabolism in photoreceptors and promote their survival. In conclusion, elevating the antioxidant capacity in retina is a promising therapy to curb the progress of inherited retinal degeneration.
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Affiliation(s)
- Xiaoyuan Ren
- Department of Genetics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France; Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17177, Sweden.
| | - Thierry Léveillard
- Department of Genetics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France.
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23
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Choi M, Yoon EG, Nam KT, Yun C. Clinical features associated with the atrophy of fellow eyes in patients with unilateral type 3 macular neovascularization. Int Ophthalmol 2022; 43:973-980. [PMID: 36057916 DOI: 10.1007/s10792-022-02499-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 08/26/2022] [Indexed: 11/28/2022]
Abstract
PURPOSE We sought to investigate the clinical features of eyes with unilateral type 3 macular neovascularization (MNV) according to the degenerative features of fellow eyes. METHODS We retrospectively reviewed 55 patients with unilateral type 3 MNV and identified degenerative features including geographic atrophy (GA) in fellow eyes using multimodal imaging. Then, the clinical features of eyes with type 3 MNV at baseline and during follow-up with anti-vascular endothelial growth factor treatment and an as-needed regimen were compared according to the degenerative features of fellow eyes. RESULTS Eighteen patients (32.7%) had GA in fellow eyes; initial disease manifestations of type 3 MNV eyes including stage, best-corrected visual acuity, and choroidal thickness (CT) did not vary between groups (all P > 0.05). During follow-up, a rate of complete fluid resolution after three monthly loading injections was not associated with GA in fellow eyes (P = 0.703), while a lower rate of early recurrence within 3 months after loading treatment was associated with thinner CT in type 3 MNV eyes and GA over one disc area in fellow eyes (P = 0.025 and P = 0.021). CONCLUSION Degenerative features of fellow eyes in patients with unilateral type 3 MNV may be associated with the clinical characteristics of affected eyes.
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Affiliation(s)
- Mihyun Choi
- Department of Ophthalmology, Korea University College of Medicine, 148 Gurodong-ro, Guro-gu, Seoul, Korea
| | - Eun Gyu Yoon
- Department of Ophthalmology, Korea University College of Medicine, 123, Jeokgeum-ro, Danwon-gu, Ansan-si, Gyeonggi-do, Seoul, Korea
| | - Ki Tae Nam
- Department of Ophthalmology, Jeju University College of Medicine, Jeju, Korea
| | - Cheolmin Yun
- Department of Ophthalmology, Korea University College of Medicine, 123, Jeokgeum-ro, Danwon-gu, Ansan-si, Gyeonggi-do, Seoul, Korea.
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24
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Aït-Ali N, Léveillard T. The Emergence of Rod-Cone Cellular Interaction. Front Genet 2022; 13:900849. [PMID: 36017494 PMCID: PMC9396122 DOI: 10.3389/fgene.2022.900849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 06/17/2022] [Indexed: 11/25/2022] Open
Abstract
We studied the origin of rod-derived cone viability factor (RdCVF) during evolution. In mammals, the nucleoredoxin-like 1 gene (NXNL1) produces a truncated thioredoxin-like protein, RdCVF, by intron retention in rod photoreceptors of the retina. This protein prevents the secondary cone degeneration in animal models of rod-cone degeneration. Extracellular RdCVF binds to a complex at the surface of the cones, composed of the basigin-1, a photoreceptor specific alternative splicing product of the basigin gene, and GLUT1, the glucose transporter. RdCVF accelerates glucose uptake allosterically. Glucose is either metabolized by aerobic glycolysis to sustain cone outer segment renewal or by the pentose phosphate pathway to support redox power to the thioredoxin RdCVFL. RdCVF signaling predates the appearance of the eye and evolved through two alternative splicing events. RdCVF signaling is observed first in hydra where it regulates an unknown signaling. A scallop RdCVF protein is produced by ciliated photoreceptors of the retina and binds its receptor, BSG1, the first occurrence of RdCVF/BSG1 signaling. In the lamprey, RdCVF metabolic signaling between rod and cones is fully operational. In the mouse, the production of BSG1 is regulated through alternative splicing. This signaling was extended to other regions of the brain, via its paralogue NXNL2.
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25
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Senabouth A, Daniszewski M, Lidgerwood GE, Liang HH, Hernández D, Mirzaei M, Keenan SN, Zhang R, Han X, Neavin D, Rooney L, Lopez Sanchez MIG, Gulluyan L, Paulo JA, Clarke L, Kearns LS, Gnanasambandapillai V, Chan CL, Nguyen U, Steinmann AM, McCloy RA, Farbehi N, Gupta VK, Mackey DA, Bylsma G, Verma N, MacGregor S, Watt MJ, Guymer RH, Powell JE, Hewitt AW, Pébay A. Transcriptomic and proteomic retinal pigment epithelium signatures of age-related macular degeneration. Nat Commun 2022; 13:4233. [PMID: 35882847 PMCID: PMC9325891 DOI: 10.1038/s41467-022-31707-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 06/29/2022] [Indexed: 11/08/2022] Open
Abstract
There are currently no treatments for geographic atrophy, the advanced form of age-related macular degeneration. Hence, innovative studies are needed to model this condition and prevent or delay its progression. Induced pluripotent stem cells generated from patients with geographic atrophy and healthy individuals were differentiated to retinal pigment epithelium. Integrating transcriptional profiles of 127,659 retinal pigment epithelium cells generated from 43 individuals with geographic atrophy and 36 controls with genotype data, we identify 445 expression quantitative trait loci in cis that are asssociated with disease status and specific to retinal pigment epithelium subpopulations. Transcriptomics and proteomics approaches identify molecular pathways significantly upregulated in geographic atrophy, including in mitochondrial functions, metabolic pathways and extracellular cellular matrix reorganization. Five significant protein quantitative trait loci that regulate protein expression in the retinal pigment epithelium and in geographic atrophy are identified - two of which share variants with cis- expression quantitative trait loci, including proteins involved in mitochondrial biology and neurodegeneration. Investigation of mitochondrial metabolism confirms mitochondrial dysfunction as a core constitutive difference of the retinal pigment epithelium from patients with geographic atrophy. This study uncovers important differences in retinal pigment epithelium homeostasis associated with geographic atrophy.
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Affiliation(s)
- Anne Senabouth
- Garvan-Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia
| | - Maciej Daniszewski
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, 3010, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, 3002, Australia
| | - Grace E Lidgerwood
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, 3010, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, 3002, Australia
| | - Helena H Liang
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, 3002, Australia
| | - Damián Hernández
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, 3010, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, 3002, Australia
| | - Mehdi Mirzaei
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Stacey N Keenan
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Ran Zhang
- Garvan-Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia
| | - Xikun Han
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, 4006, Australia
| | - Drew Neavin
- Garvan-Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia
| | - Louise Rooney
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | | | - Lerna Gulluyan
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Linda Clarke
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, 3002, Australia
| | - Lisa S Kearns
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, 3002, Australia
| | | | - Chia-Ling Chan
- Garvan-Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia
| | - Uyen Nguyen
- Garvan-Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia
| | - Angela M Steinmann
- Garvan-Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia
| | - Rachael A McCloy
- Garvan-Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia
| | - Nona Farbehi
- Garvan-Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia
| | - Vivek K Gupta
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - David A Mackey
- Lions Eye Institute, Centre for Vision Sciences, University of Western Australia, Perth, WA, 6009, Australia
- School of Medicine, University of Tasmania, Hobart, TAS, 7005, Australia
| | - Guy Bylsma
- Lions Eye Institute, Centre for Vision Sciences, University of Western Australia, Perth, WA, 6009, Australia
| | - Nitin Verma
- School of Medicine, University of Tasmania, Hobart, TAS, 7005, Australia
| | - Stuart MacGregor
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, 4006, Australia
| | - Matthew J Watt
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Robyn H Guymer
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, 3002, Australia
- Department of Surgery, Ophthalmology, Royal Victorian Eye and Ear Hospital, The University of Melbourne, East Melbourne, VIC, 3002, Australia
| | - Joseph E Powell
- Garvan-Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia.
- UNSW Cellular Genomics Futures Institute, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Alex W Hewitt
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, 3002, Australia.
- School of Medicine, University of Tasmania, Hobart, TAS, 7005, Australia.
- Department of Surgery, Ophthalmology, Royal Victorian Eye and Ear Hospital, The University of Melbourne, East Melbourne, VIC, 3002, Australia.
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, 7000, Australia.
| | - Alice Pébay
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, 3010, Australia.
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, 3002, Australia.
- Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3010, Australia.
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26
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Aparicio A, Camacho ET, Philp NJ, Wirkus SA. A mathematical model of GLUT1 modulation in rods and RPE and its differential impact in cell metabolism. Sci Rep 2022; 12:10645. [PMID: 35739198 PMCID: PMC9226191 DOI: 10.1038/s41598-022-13950-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 05/31/2022] [Indexed: 11/10/2022] Open
Abstract
We present a mathematical model of key glucose metabolic pathways in two cells of the human retina: the rods and the retinal pigmented epithelium (RPE). Computational simulations of glucose transporter 1 (GLUT1) inhibition in the model accurately reproduce experimental data from conditional knockout mice and reveal that modification of GLUT1 expression levels of both cells differentially impacts their metabolism. We hypothesize that, under glucose scarcity, the RPE's energy producing pathways are altered in order to preserve its functionality, impacting the photoreceptors' outer segment renewal. On the other hand, when glucose is limited in the rods, aerobic glycolysis is preserved, which maintains the lactate contribution to the RPE.
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Affiliation(s)
- Andrea Aparicio
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ, USA.
| | - Erika T Camacho
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ, USA
| | - Nancy J Philp
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Stephen A Wirkus
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ, USA
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27
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Park C, Noh JS, Jung Y, Leem SH, Hyun JW, Chang YC, Kwon TK, Kim GY, Lee H, Choi YH. Fisetin Attenuated Oxidative Stress-Induced Cellular Damage in ARPE-19 Human Retinal Pigment Epithelial Cells Through Nrf2-Mediated Activation of Heme Oxygenase-1. Front Pharmacol 2022; 13:927898. [PMID: 35784747 PMCID: PMC9243462 DOI: 10.3389/fphar.2022.927898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/02/2022] [Indexed: 11/13/2022] Open
Abstract
Fisetin is a kind of bioactive flavonol, widely present in various fruits such as strawberries and apples, and is known to act as a potent free radical scavenger. However, the mechanism of action related to the antioxidant activity of this compound in human retinal pigment epithelial (RPE) cells is not precisely known. In this study, we aimed to investigate whether fisetin could attenuate oxidative stress-induced cytotoxicity on human RPE ARPE-19 cells. To mimic oxidative stress, ARPE-19 cells were treated with hydrogen peroxide (H2O2), and fisetin significantly inhibited H2O2-induced loss of cell viability and increase of intracellular reactive oxygen species (ROS) production. Fisetin also markedly attenuated DNA damage and apoptosis in H2O2-treated ARPE-19 cells. Moreover, mitochondrial dysfunction in H2O2-treated cells was alleviated in the presence of fisetin as indicated by preservation of mitochondrial membrane potential, increase of Bcl-2/Bax expression ratio, and suppression of cytochrome c release into the cytoplasm. In addition, fisetin enhanced phosphorylation and nuclear translocation of nuclear factor erythroid 2 related factor 2 (Nrf2), which was associated with increased expression and activity of heme oxygenase-1 (HO-1). However, the HO-1 inhibitor, zinc protoporphyrin, significantly reversed the protective effect of fisetin against H2O2-mediated ARPE-19 cell injury. Therefore, our results suggest that Nrf2-mediated activation of antioxidant enzyme HO-1 may play an important role in the ROS scavenging activity of fisetin in RPE cells, contributing to the amelioration of oxidative stress-induced ocular disorders.
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Affiliation(s)
- Cheol Park
- Division of Basic Sciences, College of Liberal Studies, Dong-Eui University, Busan, South Korea
| | - Jeong Sook Noh
- Department of Food Science and Nutrition, Tongmyong University, Busan, South Korea
| | - Youngmi Jung
- Department of Integrated Biological Science, Pusan National University, Busan, South Korea
- Department of Biological Sciences, Pusan National University, Busan, South Korea
| | - Sun-Hee Leem
- Department of Biomedical Sciences, Dong-A University, Busan, South Korea
- Department of Health Sciences, Dong-A University, Busan, South Korea
| | - Jin Won Hyun
- Department of Biochemistry, College of Medicine, Jeju National University, Jeju, South Korea
| | - Young-Chae Chang
- Research Institute of Biomedical Engineering and Department of Medicine, Catholic University of Daegu School of Medicine, Daegu, South Korea
| | - Taeg Kyu Kwon
- Department of Immunology, School of Medicine, Keimyung University, Daegu, South Korea
| | - Gi-Young Kim
- Department of Marine Life Science, Jeju National University, Jeju, South Korea
| | - Hyesook Lee
- Department of Convergence Medicine, Pusan National University School of Medicine, Yangsan, South Korea
- *Correspondence: Hyesook Lee, ; Yung Hyun Choi,
| | - Yung Hyun Choi
- Anti-Aging Research Center and Core-Facility Center for Tissue Regeneration, Dong-Eui University, Busan, South Korea
- Department of Biochemistry, Dong-Eui University College of Korean Medicine, Busan, South Korea
- *Correspondence: Hyesook Lee, ; Yung Hyun Choi,
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28
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Santos FM, Mesquita J, Castro-de-Sousa JP, Ciordia S, Paradela A, Tomaz CT. Vitreous Humor Proteome: Targeting Oxidative Stress, Inflammation, and Neurodegeneration in Vitreoretinal Diseases. Antioxidants (Basel) 2022; 11:antiox11030505. [PMID: 35326156 PMCID: PMC8944522 DOI: 10.3390/antiox11030505] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 03/03/2022] [Accepted: 03/04/2022] [Indexed: 12/12/2022] Open
Abstract
Oxidative stress is defined as an unbalance between pro-oxidants and antioxidants, as evidenced by an increase in reactive oxygen and reactive nitrogen species production over time. It is important in the pathophysiology of retinal disorders such as diabetic retinopathy, age-related macular degeneration, retinal detachment, and proliferative vitreoretinopathy, which are the focus of this article. Although the human organism’s defense mechanisms correct autoxidation caused by endogenous or exogenous factors, this may be insufficient, causing an imbalance in favor of excessive ROS production or a weakening of the endogenous antioxidant system, resulting in molecular and cellular damage. Furthermore, modern lifestyles and environmental factors contribute to increased chemical exposure and stress induction, resulting in oxidative stress. In this review, we discuss the current information about oxidative stress and the vitreous proteome with a special focus on vitreoretinal diseases. Additionally, we explore therapies using antioxidants in an attempt to rescue the body from oxidation, restore balance, and maximize healthy body function, as well as new investigational therapies that have shown significant therapeutic potential in preclinical studies and clinical trial outcomes, along with their goals and strategic approaches to combat oxidative stress.
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Affiliation(s)
- Fátima Milhano Santos
- CICS-UBI—Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, 6201-001 Covilhã, Portugal; or (J.P.C.-d.-S.)
- Unidad de Proteomica, Centro Nacional de Biotecnología, CSIC, Campus de Cantoblanco, 28049 Madrid, Spain; (S.C.); (A.P.)
- C4-UBI, Cloud Computing Competence Centre, University of Beira Interior, 6200-501 Covilhã, Portugal
- Correspondence: (F.M.S.); (C.T.T.); Tel.: +351-275-319-700 (C.T.T.)
| | - Joana Mesquita
- CICS-UBI—Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, 6201-001 Covilhã, Portugal; or (J.P.C.-d.-S.)
| | - João Paulo Castro-de-Sousa
- CICS-UBI—Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, 6201-001 Covilhã, Portugal; or (J.P.C.-d.-S.)
- Department of Ophthalmology, Centro Hospitalar de Leiria, 2410-197 Leiria, Portugal
| | - Sergio Ciordia
- Unidad de Proteomica, Centro Nacional de Biotecnología, CSIC, Campus de Cantoblanco, 28049 Madrid, Spain; (S.C.); (A.P.)
| | - Alberto Paradela
- Unidad de Proteomica, Centro Nacional de Biotecnología, CSIC, Campus de Cantoblanco, 28049 Madrid, Spain; (S.C.); (A.P.)
| | - Cândida Teixeira Tomaz
- CICS-UBI—Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, 6201-001 Covilhã, Portugal; or (J.P.C.-d.-S.)
- C4-UBI, Cloud Computing Competence Centre, University of Beira Interior, 6200-501 Covilhã, Portugal
- Chemistry Department, Faculty of Sciences, University of Beira Interior, 6201-001 Covilhã, Portugal
- Correspondence: (F.M.S.); (C.T.T.); Tel.: +351-275-319-700 (C.T.T.)
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29
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Damsgaard C, Country MW. The Opto-Respiratory Compromise: Balancing Oxygen Supply and Light Transmittance in the Retina. Physiology (Bethesda) 2022; 37:101-113. [PMID: 34843655 PMCID: PMC9159541 DOI: 10.1152/physiol.00027.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The light-absorbing retina has an exceptionally high oxygen demand, which imposes two conflicting needs: high rates of blood perfusion and an unobstructed light path devoid of blood vessels. This review discusses mechanisms and physiological trade-offs underlying retinal oxygen supply in vertebrates and examines how these physiological systems supported the evolution of vision.
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Affiliation(s)
- Christian Damsgaard
- 1Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark,2Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Michael W. Country
- 3Retinal Neurophysiology Section, National Eye Institute,
National Institutes of Health, Bethesda, Maryland
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30
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Zouache MA. Variability in Retinal Neuron Populations and Associated Variations in Mass Transport Systems of the Retina in Health and Aging. Front Aging Neurosci 2022; 14:778404. [PMID: 35283756 PMCID: PMC8914054 DOI: 10.3389/fnagi.2022.778404] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 01/13/2022] [Indexed: 11/17/2022] Open
Abstract
Aging is associated with a broad range of visual impairments that can have dramatic consequences on the quality of life of those impacted. These changes are driven by a complex series of alterations affecting interactions between multiple cellular and extracellular elements. The resilience of many of these interactions may be key to minimal loss of visual function in aging; yet many of them remain poorly understood. In this review, we focus on the relation between retinal neurons and their respective mass transport systems. These metabolite delivery systems include the retinal vasculature, which lies within the inner portion of the retina, and the choroidal vasculature located externally to the retinal tissue. A framework for investigation is proposed and applied to identify the structures and processes determining retinal mass transport at the cellular and tissue levels. Spatial variability in the structure of the retina and changes observed in aging are then harnessed to explore the relation between variations in neuron populations and those seen among retinal metabolite delivery systems. Existing data demonstrate that the relation between inner retinal neurons and their mass transport systems is different in nature from that observed between the outer retina and choroid. The most prominent structural changes observed across the eye and in aging are seen in Bruch’s membrane, which forms a selective barrier to mass transfers at the interface between the choroidal vasculature and the outer retina.
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31
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Insights into pathological mechanisms and interventions revealed by analyzing a mathematical model for cone metabolism. Biosci Rep 2022; 42:230791. [PMID: 35156683 PMCID: PMC8905305 DOI: 10.1042/bsr20212457] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 01/14/2022] [Accepted: 02/11/2022] [Indexed: 11/17/2022] Open
Abstract
This work analyzes a mathematical model for the metabolic dynamics of a cone photoreceptor, which is the first model to account for energy generation from fatty acids oxidation of shed photoreceptor outer segments (POS). Multiple parameter bifurcation analysis shows that joint variations in external glucose, the efficiency of glucose transporter 1 (GLUT1), lipid utilization for POS renewal, and oxidation of fatty acids affect the cone’s metabolic vitality and its capability to adapt under glucose-deficient conditions. The analysis further reveals that when glucose is scarce, cone viability cannot be sustained by only fueling energy production in the mitochondria, but it also requires supporting anabolic processes to create lipids necessary for cell maintenance and repair. In silico experiments are used to investigate how the duration of glucose deprivation impacts the cell without and with a potential GLUT1 or oxidation of fatty acids intervention as well as a dual intervention. The results show that for prolonged duration of glucose deprivation, the cone metabolic system does not recover with higher oxidation of fatty acids and requires greater effectiveness of GLUT1 to recover. Finally, time-varying global sensitivity analysis (GSA) is applied to assess the sensitivity of the model outputs of interest to changes and uncertainty in the parameters at specific times. The results reveal a critical temporal window where there would be more flexibility for interventions to rescue a cone cell from the detrimental consequences of glucose shortage.
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32
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Yang TT, Li H, Dong LJ. Role of glycolysis in retinal vascular endothelium, glia, pigment epithelium, and photoreceptor cells and as therapeutic targets for related retinal diseases. Int J Ophthalmol 2021; 14:1302-1309. [PMID: 34540603 DOI: 10.18240/ijo.2021.09.02] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/16/2021] [Indexed: 02/08/2023] Open
Abstract
Glycolysis produces large amounts of adenosine triphosphate (ATP) in a short time. The retinal vascular endothelium feeds itself primarily through aerobic glycolysis with less ATP. But when it generates new vessels, aerobic glycolysis provides rapid and abundant ATP support for angiogenesis, and thus inhibition of glycolysis in endothelial cells can be a target for the treatment of neovascularization. Aerobic glycolysis has a protective effect on Müller cells, and it can provide with a target for visual protection and maintenance of the blood-retinal barrier. Under physiological conditions, the mitochondria of RPE can use lactic acid produced by photoreceptor cells as an energy source to provide ATP for survival. In pathological conditions, because RPE cells avoid their oxidative damage by increasing glycolysis, a large number of glycolysis products accumulate, which in turn has a toxic effect on photoreceptor cells. This shows that stabilizing the function of RPE mitochondria may become a target for the treatment of diseases such as retinal degeneration. The decrease of aerobic glycolysis leads to the decline of photoreceptor cell function and impaired vision; therefore, aerobic glycolysis of stable photoreceptor cells provides a reliable target for delaying vision loss. It is of great significance to study the role of glycolysis in various retinal cells for the targeted treatment of ocular fundus diseases.
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Affiliation(s)
- Ting-Ting Yang
- Editorial Department of Chinese Journal of Ocular Fundus Diseases, West China Hospital of Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Hui Li
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin 300384, China
| | - Li-Jie Dong
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin 300384, China
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33
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Bai J, Li Y, Li T, Zhang W, Fan M, Zhang K, Qian H, Zhang H, Qi X, Wang L. Comparison of Different Soluble Dietary Fibers during the In Vitro Fermentation Process. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:7446-7457. [PMID: 33951908 DOI: 10.1021/acs.jafc.1c00237] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Soluble dietary fibers being fermented by gut microbiota constitute a pivotal prerequisite for soluble dietary fibers exhibiting physiological functions. However, the relationship between fiber type and gut microbiota metabolism remains unclear. The purpose of this study was to investigate and compare the effect of fiber types on short-chain fatty acid (SCFA) biosynthesis in a simulated colon. Results showed that different soluble dietary fibers caused distinct metabolic profiles both in SCFAs and organic acids. Further analysis revealed that the SCFA biosynthesis pathway was related to the chain structure of fiber polysaccharides. Moreover, the microbial community structure showed substantial difference among experimental groups. Parabacteroides was substantially elevated in the resistant starch group, while Lactobacillus was the predominant genus in other groups. Correlation analysis further revealed that SCFA biosynthesis was correlated with microbial taxa at different taxonomic levels. Totally, the present study provided an insight into targeted intervention of gut microorganisms for dictating SCFA and organic acid production.
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Affiliation(s)
- Junying Bai
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Yan Li
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Tingting Li
- Department of Food Science and Engineering, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, Jiangsu Province, China
| | - Wenhui Zhang
- Institute of Food Science, Tibet Academy of Agricultural and Animal Husbandry Sciences, Lasa 850000, China
| | - Mingcong Fan
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Kuiliang Zhang
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Haifeng Qian
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Hui Zhang
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Xiguang Qi
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Li Wang
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
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34
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Lagarde D, Jeanson Y, Portais JC, Galinier A, Ader I, Casteilla L, Carrière A. Lactate Fluxes and Plasticity of Adipose Tissues: A Redox Perspective. Front Physiol 2021; 12:689747. [PMID: 34276410 PMCID: PMC8278056 DOI: 10.3389/fphys.2021.689747] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/09/2021] [Indexed: 12/18/2022] Open
Abstract
Lactate, a metabolite produced when the glycolytic flux exceeds mitochondrial oxidative capacities, is now viewed as a critical regulator of metabolism by acting as both a carbon and electron carrier and a signaling molecule between cells and tissues. In recent years, increasing evidence report its key role in white, beige, and brown adipose tissue biology, and highlights new mechanisms by which lactate participates in the maintenance of whole-body energy homeostasis. Lactate displays a wide range of biological effects in adipose cells not only through its binding to the membrane receptor but also through its transport and the subsequent effect on intracellular metabolism notably on redox balance. This study explores how lactate regulates adipocyte metabolism and plasticity by balancing intracellular redox state and by regulating specific signaling pathways. We also emphasized the contribution of adipose tissues to the regulation of systemic lactate metabolism, their roles in redox homeostasis, and related putative physiopathological repercussions associated with their decline in metabolic diseases and aging.
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Affiliation(s)
- Damien Lagarde
- Goodman Cancer Research Center, McGill University, Montreal, QC, Canada.,Department of Biochemistry, McGill University, Montreal, QC, Canada.,Institut RESTORE, UMR 1301 INSERM, 5070 CNRS, Université Paul Sabatier, Toulouse, France
| | - Yannick Jeanson
- Institut RESTORE, UMR 1301 INSERM, 5070 CNRS, Université Paul Sabatier, Toulouse, France
| | - Jean-Charles Portais
- Institut RESTORE, UMR 1301 INSERM, 5070 CNRS, Université Paul Sabatier, Toulouse, France.,MetaboHUB-MetaToul, National Infrastructure of Metabolomics and Fluxomics, Toulouse, France
| | - Anne Galinier
- Institut RESTORE, UMR 1301 INSERM, 5070 CNRS, Université Paul Sabatier, Toulouse, France.,Institut Fédératif de Biologie, CHU Purpan, Toulouse, France
| | - Isabelle Ader
- Institut RESTORE, UMR 1301 INSERM, 5070 CNRS, Université Paul Sabatier, Toulouse, France
| | - Louis Casteilla
- Institut RESTORE, UMR 1301 INSERM, 5070 CNRS, Université Paul Sabatier, Toulouse, France
| | - Audrey Carrière
- Institut RESTORE, UMR 1301 INSERM, 5070 CNRS, Université Paul Sabatier, Toulouse, France
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35
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Abstract
The outer retina is nourished from the choroid, a capillary bed just inside the sclera. O2, glucose, and other nutrients diffuse out of the choroid and then filter through a monolayer of retinal pigment epithelium (RPE) cells to fuel the retina. Recent studies of energy metabolism have revealed striking differences between retinas and RPE cells in the ways that they extract energy from fuels. The purpose of this review is to suggest and evaluate the hypothesis that the retina and RPE have complementary metabolic roles that make them depend on each other for survival and for their abilities to perform essential and specialized functions. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- James B Hurley
- Departments of Biochemistry and Ophthalmology, University of Washington, Seattle, Washington 98115, USA;
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36
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Dhingra A, Sharp RC, Kim T, Popov AV, Ying GS, Pietrofesa RA, Park K, Christofidou-Solomidou M, Boesze-Battaglia K. Assessment of a Small Molecule Synthetic Lignan in Enhancing Oxidative Balance and Decreasing Lipid Accumulation in Human Retinal Pigment Epithelia. Int J Mol Sci 2021; 22:5764. [PMID: 34071220 PMCID: PMC8198017 DOI: 10.3390/ijms22115764] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 01/03/2023] Open
Abstract
Visual function depends on the intimate structural, functional and metabolic interactions between the retinal pigment epithelium (RPE) and the neural retina. The daily phagocytosis of the photoreceptor outer segment tips by the overlaying RPE provides essential nutrients for the RPE itself and photoreceptors through intricate metabolic synergy. Age-related retinal changes are often characterized by metabolic dysregulation contributing to increased lipid accumulation and peroxidation as well as the release of proinflammatory cytokines. LGM2605 is a synthetic lignan secoisolariciresinol diglucoside (SDG) with free radical scavenging, antioxidant and anti-inflammatory properties demonstrated in diverse in vitro and in vivo inflammatory disease models. In these studies, we tested the hypothesis that LGM2605 may be an attractive small-scale therapeutic that protects RPE against inflammation and restores its metabolic capacity under lipid overload. Using an in vitro model in which loss of the autophagy protein, LC3B, results in defective phagosome degradation and metabolic dysregulation, we show that lipid overload results in increased gasdermin cleavage, IL-1 β release, lipid accumulation and decreased oxidative capacity. The addition of LGM2605 resulted in enhanced mitochondrial capacity, decreased lipid accumulation and amelioration of IL-1 β release in a model of defective lipid homeostasis. Collectively, these studies suggest that lipid overload decreases mitochondrial function and increases the inflammatory response, with LGM2605 acting as a protective agent.
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Affiliation(s)
- Anuradha Dhingra
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.D.); (R.C.S.)
| | - Rachel C. Sharp
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.D.); (R.C.S.)
| | - Taewan Kim
- Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Anatoliy V. Popov
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Gui-Shuang Ying
- Center for Preventive Ophthalmology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (G.-S.Y.); (K.P.)
| | - Ralph A. Pietrofesa
- Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (R.A.P.); (M.C.-S.)
| | - Kyewon Park
- Center for Preventive Ophthalmology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (G.-S.Y.); (K.P.)
| | - Melpo Christofidou-Solomidou
- Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (R.A.P.); (M.C.-S.)
| | - Kathleen Boesze-Battaglia
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.D.); (R.C.S.)
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Krueger K, Boehme E, Klettner AK, Zille M. The potential of marine resources for retinal diseases: a systematic review of the molecular mechanisms. Crit Rev Food Sci Nutr 2021; 62:7518-7560. [PMID: 33970706 DOI: 10.1080/10408398.2021.1915242] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We rely on vision more than on any other sense to obtain information about our environment. Hence, the loss or even impairment of vision profoundly affects our quality of life. Diet or food components have already demonstrated beneficial effects on the development of retinal diseases. Recently, there has been a growing interest in resources from marine animals and plants for the prevention of retinal diseases through nutrition. Especially fish intake and omega-3 fatty acids have already led to promising results, including associations with a reduced incidence of retinal diseases. However, the underlying molecular mechanisms are insufficiently explained. The aim of this review was to summarize the known mechanistic effects of marine resources on the pathophysiological processes in retinal diseases. We performed a systematic literature review following the PRISMA guidelines and identified 107 studies investigating marine resources in the context of retinal diseases. Of these, 46 studies described the underlying mechanisms including anti-inflammatory, antioxidant, antiangiogenic/vasoprotective, cytoprotective, metabolic, and retinal function effects, which we critically summarize. We further discuss perspectives on the use of marine resources for human nutrition to prevent retinal diseases with a particular focus on regulatory aspects, health claims, safety, and bioavailability.
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Affiliation(s)
- Kristin Krueger
- Department of Marine Biotechnology, Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, Lübeck, Germany
| | - Elke Boehme
- Department of Marine Biotechnology, Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, Lübeck, Germany
| | - Alexa Karina Klettner
- Department of Ophthalmology, University Medical Center, University of Kiel, Quincke Research Center, Kiel, Germany
| | - Marietta Zille
- Department of Marine Biotechnology, Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, Lübeck, Germany.,Institute for Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany
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Viegas FO, Neuhauss SCF. A Metabolic Landscape for Maintaining Retina Integrity and Function. Front Mol Neurosci 2021; 14:656000. [PMID: 33935647 PMCID: PMC8081888 DOI: 10.3389/fnmol.2021.656000] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/22/2021] [Indexed: 01/27/2023] Open
Abstract
Neurons have high metabolic demands that are almost exclusively met by glucose supplied from the bloodstream. Glucose is utilized in complex metabolic interactions between neurons and glia cells, described by the astrocyte-neuron lactate shuttle (ANLS) hypothesis. The neural retina faces similar energy demands to the rest of the brain, with additional high anabolic needs to support continuous renewal of photoreceptor outer segments. This demand is met by a fascinating variation of the ANLS in which photoreceptors are the central part of a metabolic landscape, using glucose and supplying surrounding cells with metabolic intermediates. In this review we summarize recent evidence on how neurons, in particular photoreceptors, meet their energy and biosynthetic requirements by comprising a metabolic landscape of interdependent cells.
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Affiliation(s)
- Filipe O Viegas
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.,Life Science Zurich Graduate School, Ph.D. Program in Molecular Life Sciences, Zurich, Switzerland
| | - Stephan C F Neuhauss
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
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Cao S, Li J, Yang K, Li H. Major ceRNA regulation and key metabolic signature analysis of intervertebral disc degeneration. BMC Musculoskelet Disord 2021; 22:249. [PMID: 33676464 PMCID: PMC7937257 DOI: 10.1186/s12891-021-04109-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 02/22/2021] [Indexed: 12/05/2022] Open
Abstract
Background and objective Intervertebral disc degeneration (IDD) is a complex multifactorial and irreversible pathological process. In IDD, multiple competing endogenous RNAs (ceRNA, including mRNA, lncRNA, and pseudogenes) can compete to bind with miRNAs. However, the potential metabolic signatures in nucleus pulposus (NP) cells remain poorly understood. This study investigated key metabolic genes and the ceRNA regulatory mechanisms in the pathogenesis of IDD based on microarray datasets. Methods We retrieved and downloaded four independent IDD microarray datasets from the Gene Expression Omnibus. Combining the predicted interactions from online databases (miRcode, miRDB, miRTarBase, and TargetScan), differentially expressed lncRNAs (DElncRNAs), miRNAs (DEmiRNAs), and mRNAs (DEmRNAs) were identified. A ceRNA network was constructed and annotated using GO and KEGG pathway enrichment analyses. Moreover, we searched the online metabolic gene set and used support vector machine (SVM) to find the critical metabolic DEmRNA(s) and other DERNAs. Differential gene expression was validated with a merged dataset. Results A total of 45 DEmRNAs, 36 DElncRNAs, and only one DEmiRNA (miR-338-3p) were identified in the IDD microarray datasets. GO and KEGG pathway enrichment analyses revealed that the DEmRNAs were predominantly enriched in the PI3K-Akt signaling pathway, MAPK signaling pathway, IL-17 signaling pathway, apoptosis, and cellular response to oxidative stress. Based on SVM screening, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK/FBPase) 2 is the critical metabolic gene with lower expression in IDD, and AC063977.6 is the key lncRNA with lower expression in IDD. The ceRNA hypothesis suggests that AC063977.6, miR-338-3p (high expression), and PFKFB2 are dysregulated as an axis in IDD. Conclusions The results suggest that lncRNA AC063977.6 correlate with PFKFB2, the vital metabolic signature gene, via targeting miR-338-3p during IDD pathogenesis. The current study may shed light on unraveling the pathogenesis of IDD. Supplementary Information The online version contains supplementary material available at 10.1186/s12891-021-04109-8.
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Affiliation(s)
- Shuai Cao
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004, China
| | - Jie Li
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004, China
| | - Kai Yang
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004, China
| | - Haopeng Li
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004, China.
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Wifvat K, Camacho ET, Wirkus S, Léveillard T. The role of RdCVFL in a mathematical model of photoreceptor interactions. J Theor Biol 2021; 520:110642. [PMID: 33636201 DOI: 10.1016/j.jtbi.2021.110642] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/08/2021] [Accepted: 02/11/2021] [Indexed: 01/16/2023]
Abstract
Recent experimental and mathematical work has shown the interdependence of the rod and cone photoreceptors with the retinal pigment epithelium in maintaining sight. Accelerated intake of glucose into the cones via the theoredoxin-like rod-derived cone viability factor (RdCVF) is needed as aerobic glycolysis is the primary source of energy production. Reactive oxidative species (ROS) result from the rod and cone metabolism and recent experimental work has shown that the long form of RdCVF (RdCVFL) helps mitigate the negative effects of ROS. In this work we investigate the role of RdCVFL in maintaining the health of the photoreceptors. The results of our mathematical model show the necessity of RdCVFL and also demonstrate additional stable modes that are present in this system. The sensitivity analysis shows the importance of glucose uptake, nutrient levels, and ROS mitigation in maintaining rod and cone health in light-damaged mouse models. Together, these suggests areas on which to focus treatment in order to prolong the photoreceptors, especially in situations where ROS is a contributing factor to their death such as retinitis pigmentosa.
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Affiliation(s)
- Kathryn Wifvat
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, United States
| | - Erika T Camacho
- School of Mathematical & Natural Sciences, Arizona State University, Glendale, AZ 85306, United States
| | - Stephen Wirkus
- School of Mathematical & Natural Sciences, Arizona State University, Glendale, AZ 85306, United States
| | - Thierry Léveillard
- INSERM, U968, Paris F-75012, France; Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris F-75012, France; CNRS, UMR_7210, Paris F-75012, France
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41
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Otsuki Y, Ito E, Mukai A, Ueno M, Yamawaki T, Sotozono C, Kinoshita S, Hamuro J. CD63 + extracellular vesicles from retinal pigment epithelial cells participate in crosstalk with macrophages in the innate inflammatory axis. Exp Eye Res 2021; 205:108496. [PMID: 33610602 DOI: 10.1016/j.exer.2021.108496] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 01/27/2021] [Accepted: 02/08/2021] [Indexed: 12/24/2022]
Abstract
The aim of the study is to clarify the participation of extracellular vesicles (EV) secreted by murine primary retinal pigment epithelial (mpRPE) cells in the cell to cell communication with macrophages (Mps), firstly described by the authors in 2016. In ocular inflammation, Mps act as sources of tumor necrosis factor-α (TNF-α), an activator of RPE cells. TNF-α stimulates the production of monocyte chemotactic protein (MCP-1) by RPE cells, thereby causing greater recruitment of Mps to the sub-RPE space. Murine RAW 264.7 Mps cells were co-cultured with C57BL/6 mouse mpRPE cells, either together or separated in transwells, vertically or horizontally connectable, with 0.40 or 0.03 μm membrane filters. The association of EV with mpRPE or RAW 264.7 was quantified by fluorescence cell sorting (FACS) using Qdot655 streptavidin-conjugated biotinylated EV. Increased levels of CD63+ EV were detected in co-cultures by western blotting or FACS analysis, in accordance with the increased production of nanoparticles (50-150 nm) detected by Nanosight tracking analysis. The gene expressions of cytokines, MCP-1, IL-6, IL-8, and VEGF in mpRPE cells and the corresponding proteins were increased in co-cultures even in transwells, vertically connected with 0.40 μm membrane filters, while the repressed TNF-α protein production was not affected. Most of the CD63+ EVs produced by mpRPE cells in co-cultures were associated with Raw264.7, but not with mpRPE cells. Semi-purified CD63+ EV secreted from mpRPE cells, increased the secretion of MCP-1, IL-6, and VEGF in co-cultures with RAW 264.7. Culture chamber separation horizontally connected with 0.03 μm membrane filters reduced this increased secretion. Collectively, mpRPE derived CD63+ EV partly participate in the sub-retinal innate inflammation. To evaluate the functional damage of RPE cells upon chronic exposure to here defined EVs will be the critical issue to uncover their roles in chronic retinal degenerative diseases.
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Affiliation(s)
- Yohei Otsuki
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Hirokoji-agaru, Kawaramachi-dori, Kamigyo-ku, Kyoto, 602-0841, Japan
| | - Eiko Ito
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Hirokoji-agaru, Kawaramachi-dori, Kamigyo-ku, Kyoto, 602-0841, Japan
| | - Atsushi Mukai
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Hirokoji-agaru, Kawaramachi-dori, Kamigyo-ku, Kyoto, 602-0841, Japan
| | - Morio Ueno
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Hirokoji-agaru, Kawaramachi-dori, Kamigyo-ku, Kyoto, 602-0841, Japan
| | - Takahiro Yamawaki
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Hirokoji-agaru, Kawaramachi-dori, Kamigyo-ku, Kyoto, 602-0841, Japan
| | - Chie Sotozono
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Hirokoji-agaru, Kawaramachi-dori, Kamigyo-ku, Kyoto, 602-0841, Japan
| | - Shigeru Kinoshita
- Department of Frontier Medical Science and Technology for Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Junji Hamuro
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Hirokoji-agaru, Kawaramachi-dori, Kamigyo-ku, Kyoto, 602-0841, Japan.
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Aggio-Bruce R, Chu-Tan JA, Wooff Y, Cioanca AV, Schumann U, Natoli R. Inhibition of microRNA-155 Protects Retinal Function Through Attenuation of Inflammation in Retinal Degeneration. Mol Neurobiol 2021; 58:835-854. [PMID: 33037565 PMCID: PMC7843561 DOI: 10.1007/s12035-020-02158-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 10/01/2020] [Indexed: 01/14/2023]
Abstract
Although extensively investigated in inflammatory conditions, the role of pro-inflammatory microRNAs (miRNAs), miR-155 and miR-146a, has not been well-studied in retinal degenerative diseases. We therefore aimed to explore the role and regulation of these miRNA in the degenerating retina, with a focus on miR-155. C57BL/6J mice were subjected to photo-oxidative damage for up to 5 days to induce focal retinal degeneration. MiR-155 expression was quantified by qRT-PCR in whole retina, serum, and small-medium extracellular vesicles (s-mEVs), and a PrimeFlow™ assay was used to identify localisation of miR-155 in retinal cells. Constitutive miR-155 knockout (KO) mice and miR-155 and miR-146a inhibitors were utilised to determine the role of these miRNA in the degenerating retina. Electroretinography was employed as a measure of retinal function, while histological quantification of TUNEL+ and IBA1+ positive cells was used to quantify photoreceptor cell death and infiltrating immune cells, respectively. Upregulation of miR-155 was detected in retinal tissue, serum and s-mEVs in response to photo-oxidative damage, localising to the nucleus of a subset of retinal ganglion cells and glial cells and in the cytoplasm of photoreceptors. Inhibition of miR-155 showed increased function from negative controls and a less pathological pattern of IBA1+ cell localisation and morphology at 5 days photo-oxidative damage. While neither dim-reared nor damaged miR-155 KO animals showed retinal histological difference from controls, following photo-oxidative damage, miR-155 KO mice showed increased a-wave relative to controls. We therefore consider miR-155 to be associated with the inflammatory response of the retina in response to photoreceptor-specific degeneration.
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Affiliation(s)
- Riemke Aggio-Bruce
- The John Curtin School of Medical Research, The Australian National University, Garran Road, Acton, Australian Capital Territory 2601 Australia
- The Australian National University Medical School, Mills Road, Australian Capital Territory, Acton, 2601 Australia
| | - Joshua A. Chu-Tan
- The John Curtin School of Medical Research, The Australian National University, Garran Road, Acton, Australian Capital Territory 2601 Australia
- The Australian National University Medical School, Mills Road, Australian Capital Territory, Acton, 2601 Australia
| | - Yvette Wooff
- The John Curtin School of Medical Research, The Australian National University, Garran Road, Acton, Australian Capital Territory 2601 Australia
- The Australian National University Medical School, Mills Road, Australian Capital Territory, Acton, 2601 Australia
| | - Adrian V. Cioanca
- The John Curtin School of Medical Research, The Australian National University, Garran Road, Acton, Australian Capital Territory 2601 Australia
| | - Ulrike Schumann
- The John Curtin School of Medical Research, The Australian National University, Garran Road, Acton, Australian Capital Territory 2601 Australia
| | - Riccardo Natoli
- The John Curtin School of Medical Research, The Australian National University, Garran Road, Acton, Australian Capital Territory 2601 Australia
- The Australian National University Medical School, Mills Road, Australian Capital Territory, Acton, 2601 Australia
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Wu DM, Ji X, Ivanchenko MV, Chung M, Piper M, Rana P, Wang SK, Xue Y, West E, Zhao SR, Xu H, Cicconet M, Xiong W, Cepko CL. Nrf2 overexpression rescues the RPE in mouse models of retinitis pigmentosa. JCI Insight 2021; 6:145029. [PMID: 33491671 PMCID: PMC7934854 DOI: 10.1172/jci.insight.145029] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/02/2020] [Indexed: 12/11/2022] Open
Abstract
Nrf2, a transcription factor that regulates the response to oxidative stress, has been shown to rescue cone photoreceptors and slow vision loss in mouse models of retinal degeneration (rd). The retinal pigment epithelium (RPE) is damaged in these models, but whether it also could be rescued by Nrf2 has not been previously examined. We used an adeno-associated virus (AAV) with an RPE-specific (Best1) promoter to overexpress Nrf2 in the RPE of rd mice. Control rd mice showed disruption of the regular array of the RPE, as well as loss of RPE cells. Cones were lost in circumscribed regions within the cone photoreceptor layer. Overexpression of Nrf2 specifically in the RPE was sufficient to rescue the RPE, as well as the disruptions in the cone photoreceptor layer. Electron microscopy showed compromised apical microvilli in control rd mice but showed preserved microvilli in Best1-Nrf2–treated mice. The rd mice treated with Best1-Nrf2 had slightly better visual acuity. Transcriptome profiling showed that Nrf2 upregulates multiple oxidative defense pathways, reversing declines seen in the glutathione pathway in control rd mice. In summary, Nrf2 overexpression in the RPE preserves RPE morphology and survival in rd mice, and it is a potential therapeutic for diseases involving RPE degeneration, including age-related macular degeneration (AMD).
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Affiliation(s)
- David M Wu
- Massachusetts Eye and Ear Infirmary Retina Service, Department of Ophthalmology.,Departments of Genetics and Ophthalmology, Blavatnik Institute, and
| | - Xuke Ji
- Massachusetts Eye and Ear Infirmary Retina Service, Department of Ophthalmology.,Departments of Genetics and Ophthalmology, Blavatnik Institute, and
| | - Maryna V Ivanchenko
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Michelle Chung
- Departments of Genetics and Ophthalmology, Blavatnik Institute, and.,Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
| | - Mary Piper
- Department of Bioinformatics, T.H. Chan Harvard School of Public Health, Boston, Massachusetts, USA
| | - Parimal Rana
- Departments of Genetics and Ophthalmology, Blavatnik Institute, and
| | - Sean K Wang
- Departments of Genetics and Ophthalmology, Blavatnik Institute, and
| | - Yunlu Xue
- Departments of Genetics and Ophthalmology, Blavatnik Institute, and
| | - Emma West
- Departments of Genetics and Ophthalmology, Blavatnik Institute, and
| | - Sophia R Zhao
- Departments of Genetics and Ophthalmology, Blavatnik Institute, and
| | - Hongbin Xu
- Departments of Genetics and Ophthalmology, Blavatnik Institute, and.,Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
| | - Marcelo Cicconet
- Image and Data Analysis Core, Harvard Medical School, Boston, Massachusetts, USA
| | - Wenjun Xiong
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Constance L Cepko
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA.,Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
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44
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Lee KS, Lin S, Copland DA, Dick AD, Liu J. Cellular senescence in the aging retina and developments of senotherapies for age-related macular degeneration. J Neuroinflammation 2021; 18:32. [PMID: 33482879 PMCID: PMC7821689 DOI: 10.1186/s12974-021-02088-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 01/15/2021] [Indexed: 12/16/2022] Open
Abstract
Age-related macular degeneration (AMD), a degenerative disease in the central macula area of the neuroretina and the supporting retinal pigment epithelium, is the most common cause of vision loss in the elderly. Although advances have been made, treatment to prevent the progressive degeneration is lacking. Besides the association of innate immune pathway genes with AMD susceptibility, environmental stress- and cellular senescence-induced alterations in pathways such as metabolic functions and inflammatory responses are also implicated in the pathophysiology of AMD. Cellular senescence is an adaptive cell process in response to noxious stimuli in both mitotic and postmitotic cells, activated by tumor suppressor proteins and prosecuted via an inflammatory secretome. In addition to physiological roles in embryogenesis and tissue regeneration, cellular senescence is augmented with age and contributes to a variety of age-related chronic conditions. Accumulation of senescent cells accompanied by an impairment in the immune-mediated elimination mechanisms results in increased frequency of senescent cells, termed “chronic” senescence. Age-associated senescent cells exhibit abnormal metabolism, increased generation of reactive oxygen species, and a heightened senescence-associated secretory phenotype that nurture a proinflammatory milieu detrimental to neighboring cells. Senescent changes in various retinal and choroidal tissue cells including the retinal pigment epithelium, microglia, neurons, and endothelial cells, contemporaneous with systemic immune aging in both innate and adaptive cells, have emerged as important contributors to the onset and development of AMD. The repertoire of senotherapeutic strategies such as senolytics, senomorphics, cell cycle regulation, and restoring cell homeostasis targeted both at tissue and systemic levels is expanding with the potential to treat a spectrum of age-related diseases, including AMD.
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Affiliation(s)
- Keng Siang Lee
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, BS8 1TD, UK
| | - Shuxiao Lin
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, BS8 1TD, UK
| | - David A Copland
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, BS8 1TD, UK
| | - Andrew D Dick
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, BS8 1TD, UK. .,Institute of Ophthalmology, University College London, London, EC1V 9EL, UK. .,National Institute for Health Research Biomedical Research Centre, Moorfields Eye Hospital, London, EC1V 2QH, UK.
| | - Jian Liu
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, BS8 1TD, UK.
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45
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Klipfel L, Cordonnier M, Thiébault L, Clérin E, Blond F, Millet-Puel G, Mohand-Saïd S, Goureau O, Sahel JA, Nandrot EF, Léveillard T. A Splice Variant in SLC16A8 Gene Leads to Lactate Transport Deficit in Human iPS Cell-Derived Retinal Pigment Epithelial Cells. Cells 2021; 10:cells10010179. [PMID: 33477551 PMCID: PMC7831140 DOI: 10.3390/cells10010179] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/05/2021] [Accepted: 01/15/2021] [Indexed: 12/27/2022] Open
Abstract
Age-related macular degeneration (AMD) is a blinding disease for which most of the patients remain untreatable. Since the disease affects the macula at the center of the retina, a structure specific to the primate lineage, rodent models to study the pathophysiology of AMD and to develop therapies are very limited. Consequently, our understanding relies mostly on genetic studies highlighting risk alleles at many loci. We are studying the possible implication of a metabolic imbalance associated with risk alleles within the SLC16A8 gene that encodes for a retinal pigment epithelium (RPE)-specific lactate transporter MCT3 and its consequences for vision. As a first approach, we report here the deficit in transepithelial lactate transport of a rare SLC16A8 allele identified during a genome-wide association study. We produced induced pluripotent stem cells (iPSCs) from the unique patient in our cohort that carries two copies of this allele. After in vitro differentiation of the iPSCs into RPE cells and their characterization, we demonstrate that the rare allele results in the retention of intron 2 of the SLC16A8 gene leading to the absence of MCT3 protein. We show using a biochemical assay that these cells have a deficit in transepithelial lactate transport.
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Affiliation(s)
- Laurence Klipfel
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - Marie Cordonnier
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - Léa Thiébault
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - Emmanuelle Clérin
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - Frédéric Blond
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - Géraldine Millet-Puel
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - Saddek Mohand-Saïd
- CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, 28 rue de Charenton, F-75012 Paris, France;
| | - Olivier Goureau
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - José-Alain Sahel
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
- CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, 28 rue de Charenton, F-75012 Paris, France;
| | - Emeline F. Nandrot
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - Thierry Léveillard
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
- Correspondence: ; Tel.: +33-153-462-548
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Sharma R, Bose D, Maminishkis A, Bharti K. Retinal Pigment Epithelium Replacement Therapy for Age-Related Macular Degeneration: Are We There Yet? Annu Rev Pharmacol Toxicol 2020; 60:553-572. [PMID: 31914900 DOI: 10.1146/annurev-pharmtox-010919-023245] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Pluripotent stem cells (PSCs) are a potential replacement tissue source for degenerative diseases. Age-related macular degeneration (AMD) is a blinding disease triggered by degeneration of the retinal pigment epithelium (RPE), a monolayer tissue that functionally supports retinal photoreceptors. Recently published clinical and preclinical studies have tested PSC-derived RPE as a potential treatment for AMD. Multiple approaches have been used to manufacture RPE cells, to validate them functionally, to confirm their safety profile, and to deliver them to patients either as suspension or as a monolayer patch. Since most of these studies are at an early regulatory approval stage, the primary outcome has been to determine the safety of RPE transplants in patients. However, preliminary signs of efficacy were observed in a few patients. Here, we review the current progress in the PSC-derived RPE transplantation field and provide a comparative assessment of various approaches under development as potential therapeutics for AMD.
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Affiliation(s)
- Ruchi Sharma
- Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Devika Bose
- Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Arvydas Maminishkis
- Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Kapil Bharti
- Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
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47
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Selective knockdown of hexokinase 2 in rods leads to age-related photoreceptor degeneration and retinal metabolic remodeling. Cell Death Dis 2020; 11:885. [PMID: 33082308 PMCID: PMC7576789 DOI: 10.1038/s41419-020-03103-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/05/2020] [Indexed: 12/13/2022]
Abstract
Photoreceptors, the primary site of phototransduction in the retina, require energy and metabolites to constantly renew their outer segments. They preferentially consume most glucose through aerobic glycolysis despite possessing abundant mitochondria and enzymes for oxidative phosphorylation (OXPHOS). Exactly how photoreceptors balance aerobic glycolysis and mitochondrial OXPHOS to regulate their survival is still unclear. We crossed rhodopsin-Cre mice with hexokinase 2 (HK2)-floxed mice to study the effect of knocking down HK2, the first rate-limiting enzyme in glycolysis, on retinal health and metabolic remodeling. Immunohistochemistry and Western blots were performed to study changes in photoreceptor-specific proteins and key enzymes in glycolysis and the tricarboxylic acid (TCA) cycle. Changes in retinal structure and function were studied by optical coherence tomography and electroretinography. Mass spectrometry was performed to profile changes in 13C-glucose-derived metabolites in glycolysis and the TCA cycle. We found that knocking down HK2 in rods led to age-related photoreceptor degeneration, evidenced by reduced expression of photoreceptor-specific proteins, age-related reductions of the outer nuclear layer, photoreceptor inner and outer segments and impaired electroretinographic responses. Loss of HK2 in rods led to upregulation of HK1, phosphorylation of pyruvate kinase muscle isozyme 2, mitochondrial stress proteins and enzymes in the TCA cycle. Mass spectrometry found that the deletion of HK2 in rods resulted in accumulation of 13C-glucose along with decreased pyruvate and increased metabolites in the TCA cycle. Our data suggest that HK2-mediated aerobic glycolysis is indispensable for the maintenance of photoreceptor structure and function and that long-term inhibition of glycolysis leads to photoreceptor degeneration.
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48
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Neethu A, Jayashree K, Senthilkumar GP, Ramesh Babu K, Vadivelan M. Circulating adropin and vascular endothelial growth factor receptor-2 levels in age-related macular degeneration and T2DM patients-A cross-sectional study. J Family Med Prim Care 2020; 9:4875-4879. [PMID: 33209815 PMCID: PMC7652138 DOI: 10.4103/jfmpc.jfmpc_813_20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 06/14/2020] [Accepted: 07/03/2020] [Indexed: 01/01/2023] Open
Abstract
Background: Macular drusen formation and angiogenesis are the two chief processes associated with age-related macular degeneration. Adropin and vascular endothelial growth factor receptor-2 (VEGFR-2) may be involved in these pathologies. By altering lipid metabolism, adropin may contribute in the early stages of age-related macular degeneration (AMD). VEGFR-2 may participate in the later form of AMD, by promoting angiogenesis. This study compared the circulatory levels of adropin and VEGFR-2 in AMD and patients without AMD and assessed their association with disease severity, to understand their possible role in AMD. Objectives: This study aimed to assess and compare the serum levels of adropin and VEGFR-2 in patients with AMD and type 2 diabetes patients without AMD, and, to investigate the correlation between these two parameters with disease severity. Methods: Our study involves two groups of 39 each. Group A (age-related macular degeneration) and Group B (diabetes patients without age-related macular degeneration). Routine parameters fasting blood sugar (FBS), lipid profile, and liver function tests (LFT) were estimated by using autoanalyzer. Serum adropin and VEGFR-2 were assessed by ELISA. Results: Among the basic parameters, systolic blood pressure and fasting blood glucose alone were significantly different across the groups. We did not find significant alterations in adropin and VEGFR-2 levels between the study groups. Our lipid profile parameters (triglycerides and total cholesterol) have significant positive association. VEGFR-2 showed a positive correlation with the severity of AMD. Adropin did not exhibit any correlation with disease severity and with VEGFR-2. Conclusion: We could not find any observable alterations of statistical significance, in adropin and VEGFR-2 levels. VEGFR-2's correlation with disease severity could be important. Adropin might have subtler roles in AMD, though not evident from our study, and requires a deeper observation at the molecular level to elucidate its function.
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Affiliation(s)
- Areekulangara Neethu
- Department of Biochemistry , Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
| | - Kuppuswami Jayashree
- Department of Biochemistry , Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
| | | | - K Ramesh Babu
- Department of Ophthalmology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
| | - Mehalingam Vadivelan
- Department of Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
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49
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Cimaglia G, Votruba M, Morgan JE, André H, Williams PA. Potential Therapeutic Benefit of NAD + Supplementation for Glaucoma and Age-Related Macular Degeneration. Nutrients 2020; 12:nu12092871. [PMID: 32961812 PMCID: PMC7551676 DOI: 10.3390/nu12092871] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/14/2020] [Accepted: 09/17/2020] [Indexed: 12/13/2022] Open
Abstract
Glaucoma and age-related macular degeneration are leading causes of irreversible blindness worldwide with significant health and societal burdens. To date, no clinical cures are available and treatments target only the manageable symptoms and risk factors (but do not remediate the underlying pathology of the disease). Both diseases are neurodegenerative in their pathology of the retina and as such many of the events that trigger cell dysfunction, degeneration, and eventual loss are due to mitochondrial dysfunction, inflammation, and oxidative stress. Here, we critically review how a decreased bioavailability of nicotinamide adenine dinucleotide (NAD; a crucial metabolite in healthy and disease states) may underpin many of these aberrant mechanisms. We propose how exogenous sources of NAD may become a therapeutic standard for the treatment of these conditions.
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Affiliation(s)
- Gloria Cimaglia
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 112 82 Stockholm, Sweden;
- School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4HQ, Wales, UK; (M.V.); (J.E.M.)
| | - Marcela Votruba
- School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4HQ, Wales, UK; (M.V.); (J.E.M.)
- Cardiff Eye Unit, University Hospital Wales, Cardiff CF14 4XW, Wales, UK
| | - James E. Morgan
- School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4HQ, Wales, UK; (M.V.); (J.E.M.)
- School of Medicine, Cardiff University, Cardiff CF14 4YS, Wales, UK
| | - Helder André
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 112 82 Stockholm, Sweden;
- Correspondence: (H.A.); (P.A.W.)
| | - Pete A. Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 112 82 Stockholm, Sweden;
- Correspondence: (H.A.); (P.A.W.)
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50
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Sinha T, Naash MI, Al-Ubaidi MR. Flavins Act as a Critical Liaison Between Metabolic Homeostasis and Oxidative Stress in the Retina. Front Cell Dev Biol 2020; 8:861. [PMID: 32984341 PMCID: PMC7481326 DOI: 10.3389/fcell.2020.00861] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 08/10/2020] [Indexed: 12/14/2022] Open
Abstract
Derivatives of the vitamin riboflavin, FAD and FMN, are essential cofactors in a multitude of bio-energetic reactions, indispensable for lipid metabolism and also are requisites in mitigating oxidative stress. Given that a balance between all these processes contributes to the maintenance of retinal homeostasis, effective regulation of riboflavin levels in the retina is paramount. However, various genetic and dietary factors have brought to fore pathological conditions that co-occur with a suboptimal level of flavins in the retina. Our focus in this review is to, comprehensively summarize all the possible metabolic and oxidative reactions which have been implicated in various retinal pathologies and to highlight the contribution flavins may have played in these. Recent research has found a sensitive method of measuring flavins in both diseased and healthy retina, presence of a novel flavin binding protein exclusively expressed in the retina, and the presence of flavin specific transporters in both the inner and outer blood-retina barriers. In light of these exciting findings, it is even more imperative to shift our focus on how the retina regulates its flavin homeostasis and what happens when this is disrupted.
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Affiliation(s)
- Tirthankar Sinha
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
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