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Izadi M, Sadri N, Abdi A, Serajian S, Jalalei D, Tahmasebi S. Epigenetic biomarkers in aging and longevity: Current and future application. Life Sci 2024; 351:122842. [PMID: 38879158 DOI: 10.1016/j.lfs.2024.122842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 06/06/2024] [Accepted: 06/12/2024] [Indexed: 06/20/2024]
Abstract
The aging process has been one of the most necessary research fields in the current century, and knowing different theories of aging and the role of different genetic, epigenetic, molecular, and environmental modulating factors in increasing the knowledge of aging mechanisms and developing appropriate diagnostic, therapeutic, and preventive ways would be helpful. One of the most conserved signs of aging is epigenetic changes, including DNA methylation, histone modifications, chromatin remodeling, noncoding RNAs, and extracellular RNAs. Numerous biological processes and hallmarks are vital in aging development, but epigenomic alterations are especially notable because of their importance in gene regulation and cellular identity. The mounting evidence points to a possible interaction between age-related epigenomic alterations and other aging hallmarks, like genome instability. To extend a healthy lifespan and possibly reverse some facets of aging and aging-related diseases, it will be crucial to comprehend global and locus-specific epigenomic modifications and recognize corresponding regulators of health and longevity. In the current study, we will aim to discuss the role of epigenomic mechanisms in aging and the most recent developments in epigenetic diagnostic biomarkers, which have the potential to focus efforts on reversing the destructive signs of aging and extending the lifespan.
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Affiliation(s)
- Mehran Izadi
- Department of Infectious and Tropical Diseases, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Synapse Laboratory Diagnostic Technologies Accelerator, Tehran, Iran; Department of Research & Technology, Zeenome Longevity Research Institute, Tehran, Iran
| | - Nariman Sadri
- Synapse Laboratory Diagnostic Technologies Accelerator, Tehran, Iran; Department of Research & Technology, Zeenome Longevity Research Institute, Tehran, Iran; School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amirhossein Abdi
- Synapse Laboratory Diagnostic Technologies Accelerator, Tehran, Iran; Department of Research & Technology, Zeenome Longevity Research Institute, Tehran, Iran; Royan Institute for Stem Cell Biology and Technology, Tehran, Iran
| | - Sahar Serajian
- Synapse Laboratory Diagnostic Technologies Accelerator, Tehran, Iran; Department of Research & Technology, Zeenome Longevity Research Institute, Tehran, Iran; Royan Institute for Stem Cell Biology and Technology, Tehran, Iran
| | - Dorsa Jalalei
- Synapse Laboratory Diagnostic Technologies Accelerator, Tehran, Iran; Department of Research & Technology, Zeenome Longevity Research Institute, Tehran, Iran; School of Pharmacy, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Safa Tahmasebi
- Synapse Laboratory Diagnostic Technologies Accelerator, Tehran, Iran; Department of Research & Technology, Zeenome Longevity Research Institute, Tehran, Iran; Department of Immunology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Camacho P, Ribeiro E, Pereira B, Varandas T, Nascimento J, Henriques J, Dutra-Medeiros M, Delgadinho M, Oliveira K, Silva C, Brito M. DNA methyltransferase expression (DNMT1, DNMT3a and DNMT3b) as a potential biomarker for anti-VEGF diabetic macular edema response. Eur J Ophthalmol 2023; 33:2267-2274. [PMID: 37082811 PMCID: PMC10590013 DOI: 10.1177/11206721231171623] [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: 10/08/2022] [Accepted: 03/28/2023] [Indexed: 04/22/2023]
Abstract
PURPOSE DNA methylation is involved in Diabetic Retinopathy progression showing a metabolic memory mechanism. However, the association of DNA methyltransferase with diabetic macular edema is still unknown. We aimed to describe the differences in DNA methyltransferase gene expression in patients with different diabetic macular edema responses. METHODS A total of 27 diabetic patients, aged 59-90 years, were prospectively enrolled in this cross-sectional study. The participants were classified into control group (CG, n = 11), diabetic macular edema responders (rDME, n = 9) and non-responder diabetic macular edema (nrDME, n = 7) after anti-vascular endothelial growth factor (anti-VEGF) treatment. Only cases with a complete ophthalmological examination, digital 133° color fundus, and SD-OCT assessments were used. After RNA extraction and first-strand cDNA synthesis, quantitative real-time PCR was performed with specific primers on the CFX Connect™ Real-Time PCR Detection System to assess differential transcriptional expression patterns. RESULTS The DNMT1 gene showed a positive correlation (r = 0.617; p = 0.043) with Best Corrected Visual Acuity (BCVA) in CG, a positive correlation (r = 0.917; p = 0.010) with HbA1c in nrDME and a negative correlation (r = -0.659; p = 0.049) with GCL-IPL thickness in rDME. DNMT3A gene showed a positive correlation (r = -0.890; p = 0.001) with Sub-foveal Choroidal thickness in rDME whereas DNMT3b gene showed a negative correlation (r = -0.815; p = 0.007) with HbA1c and RNFL (r = -0.664; p = 0.026) in CG. CONCLUSIONS Patients with similar metabolic profile risk factors showed associated DNA methyltransferase transcriptional expression patterns differences fitting with the anti-VEGF diabetic macular edema response. Further studies are needed to clarify if these results (1) reflect disease evolution, (2) translate the therapeutic impact, (3) or can help to predict the therapeutic resistance profile.
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Affiliation(s)
- Pedro Camacho
- H&TRC- Health & Technology Research Center, ESTeSL- Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal
- Ophtalmology Institute Dr. Gama Pinto, Lisbon, Portugal
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Edna Ribeiro
- H&TRC- Health & Technology Research Center, ESTeSL- Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal
| | - Bruno Pereira
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisbon, Portugal
- Retina Institute of Lisbon, Lisbon, Portugal
| | | | - João Nascimento
- Retina Institute of Lisbon, Lisbon, Portugal
- Beatriz Ângelo Hospital, Lisbon, Portugal
| | | | - Marco Dutra-Medeiros
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisbon, Portugal
- Central Lisbon Hospital Center, Lisbon, Portugal
| | - Mariana Delgadinho
- H&TRC- Health & Technology Research Center, ESTeSL- Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal
| | - Ketlyn Oliveira
- H&TRC- Health & Technology Research Center, ESTeSL- Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal
| | - Carina Silva
- H&TRC- Health & Technology Research Center, ESTeSL- Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal
| | - Miguel Brito
- H&TRC- Health & Technology Research Center, ESTeSL- Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal
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Liu DD, Zhang CY, Zhang JT, Gu LM, Xu GT, Zhang JF. Epigenetic modifications and metabolic memory in diabetic retinopathy: beyond the surface. Neural Regen Res 2023; 18:1441-1449. [PMID: 36571340 PMCID: PMC10075108 DOI: 10.4103/1673-5374.361536] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 10/10/2022] [Accepted: 10/26/2022] [Indexed: 11/19/2022] Open
Abstract
Epigenetics focuses on DNA methylation, histone modification, chromatin remodeling, noncoding RNAs, and other gene regulation mechanisms beyond the DNA sequence. In the past decade, epigenetic modifications have drawn more attention as they participate in the development and progression of diabetic retinopathy despite tight control of glucose levels. The underlying mechanisms of epigenetic modifications in diabetic retinopathy still urgently need to be elucidated. The diabetic condition facilitates epigenetic changes and influences target gene expression. In this review, we summarize the involvement of epigenetic modifications and metabolic memory in the development and progression of diabetic retinopathy and propose novel insights into the treatment of diabetic retinopathy.
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Affiliation(s)
- Dan-Dan Liu
- Department of Ophthalmology of Tongji Hospital, Tongji Eye Institute, Department of Regenerative Medicine, and Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Chao-Yang Zhang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People’s Hospital), Shanghai Jiao Tong University, Shanghai, China
- National Clinical Research Center for Eye Diseases; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photomedicine; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Jing-Ting Zhang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People’s Hospital), Shanghai Jiao Tong University, Shanghai, China
- National Clinical Research Center for Eye Diseases; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photomedicine; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Li-Min Gu
- Department of Ophthalmology, Shanghai Aier Eye Hospital, Shanghai, China
| | - Guo-Tong Xu
- Department of Ophthalmology of Tongji Hospital, Tongji Eye Institute, Department of Regenerative Medicine, and Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Jing-Fa Zhang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People’s Hospital), Shanghai Jiao Tong University, Shanghai, China
- National Clinical Research Center for Eye Diseases; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photomedicine; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
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Hypoxia-induced transcriptional differences in African and Asian versus European diabetic cybrids. Sci Rep 2023; 13:3818. [PMID: 36882486 PMCID: PMC9992459 DOI: 10.1038/s41598-023-30518-x] [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: 07/22/2022] [Accepted: 02/24/2023] [Indexed: 03/09/2023] Open
Abstract
Diabetic retinopathy (DR) is the most common diabetic microvascular complication and cause of blindness in adults under the age of 65. Our results suggest that, when comparing transcriptomes of cultures grown in hypoxic conditions versus room-air, cybrids containing mitochondria from African and Asian diabetic subjects ([Afr + Asi]/DM) have some uniquely different transcriptome profiles compared to European/diabetic (Euro/DM) cybrids (e.g., fatty acid metabolism: EnrichR rank 10 in [Afr + Asi]/DM, rank 85 in Euro/DM; Endocytosis: rank 25 in [Afr + Asi]/DM, rank 5 in Euro/DM; Ubiquitin Mediated Proteolysis: rank 34 in [Afr + Asi]/DM, rank 7 in Euro/DM). As determined by both RNA-seq and qRT-PCR results, transcription of the gene encoding oleoyl-ACP hydrolase (OLAH) was significantly increased in [Afr + Asi]/DM cybrids compared to Euro/DM cybrids in hypoxic conditions. Additionally, our results show that in hypoxic conditions, Euro/DM cybrids and [Afr + Asi]/DM cybrids show similar decreases in ROS production. All cybrids showed decreased ZO1-minus protein levels, but their phagocytic functions were not significantly altered in hypoxic conditions. In conclusion, our findings suggest that the "molecular memory" imparted by [Afr + Asi]/DM mtDNA may act through one of the molecular pathways seen in transcriptome analysis, such as fatty acid metabolism, without significantly changing essential RPE functions.
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Sohn J, Lee SE, Shim EY. DNA Damage and Repair in Eye Diseases. Int J Mol Sci 2023; 24:3916. [PMID: 36835325 PMCID: PMC9964121 DOI: 10.3390/ijms24043916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/30/2023] [Accepted: 02/02/2023] [Indexed: 02/17/2023] Open
Abstract
Vision is vital for daily activities, and yet the most common eye diseases-cataracts, DR, ARMD, and glaucoma-lead to blindness in aging eyes. Cataract surgery is one of the most frequently performed surgeries, and the outcome is typically excellent if there is no concomitant pathology present in the visual pathway. In contrast, patients with DR, ARMD and glaucoma often develop significant visual impairment. These often-multifactorial eye problems can have genetic and hereditary components, with recent data supporting the role of DNA damage and repair as significant pathogenic factors. In this article, we discuss the role of DNA damage and the repair deficit in the development of DR, ARMD and glaucoma.
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Affiliation(s)
- Joanna Sohn
- Department of Molecular Medicine, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
- Keystone School, 119 E. Craig Pl., San Antonio, TX 78212, USA
| | - Sang-Eun Lee
- Department of Molecular Medicine, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Eun-Yong Shim
- Department of Molecular Medicine, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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Cai C, Meng C, He S, Gu C, Lhamo T, Draga D, Luo D, Qiu Q. DNA methylation in diabetic retinopathy: pathogenetic role and potential therapeutic targets. Cell Biosci 2022; 12:186. [DOI: 10.1186/s13578-022-00927-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 11/07/2022] [Indexed: 11/18/2022] Open
Abstract
Abstract
Background
Diabetic retinopathy (DR), a specific neuron-vascular complication of diabetes, is a major cause of vision loss among middle-aged people worldwide, and the number of DR patients will increase with the increasing incidence of diabetes. At present, it is limited in difficult detection in the early stages, limited treatment and unsatisfactory treatment effects in the advanced stages.
Main body
The pathogenesis of DR is complicated and involves epigenetic modifications, oxidative stress, inflammation and neovascularization. These factors influence each other and jointly promote the development of DR. DNA methylation is the most studied epigenetic modification, which has been a key role in the regulation of gene expression and the occurrence and development of DR. Thus, this review investigates the relationship between DNA methylation and other complex pathological processes in the development of DR. From the perspective of DNA methylation, this review provides basic insights into potential biomarkers for diagnosis, preventable risk factors, and novel targets for treatment.
Conclusion
DNA methylation plays an indispensable role in DR and may serve as a prospective biomarker of this blinding disease in its relatively early stages. In combination with inhibitors of DNA methyltransferases can be a potential approach to delay or even prevent patients from getting advanced stages of DR.
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Wu Y, Zou H. Research Progress on Mitochondrial Dysfunction in Diabetic Retinopathy. Antioxidants (Basel) 2022; 11:2250. [PMID: 36421435 PMCID: PMC9686704 DOI: 10.3390/antiox11112250] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/07/2022] [Accepted: 11/12/2022] [Indexed: 09/07/2023] Open
Abstract
Diabetic Retinopathy (DR) is one of the most important microvascular complications of diabetes mellitus, which can lead to blindness in severe cases. Mitochondria are energy-producing organelles in eukaryotic cells, which participate in metabolism and signal transduction, and regulate cell growth, differentiation, aging, and death. Metabolic changes of retinal cells and epigenetic changes of mitochondria-related genes under high glucose can lead to mitochondrial dysfunction and induce mitochondrial pathway apoptosis. In addition, mitophagy and mitochondrial dynamics also change adaptively. These mechanisms may be related to the occurrence and progression of DR, and also provide valuable clues for the prevention and treatment of DR. This article reviews the mechanism of DR induced by mitochondrial dysfunction, and the prospects for related treatment.
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Affiliation(s)
- Yiwei Wu
- Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Haidong Zou
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
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Targeted Mitochondrial Epigenetics: A New Direction in Alzheimer’s Disease Treatment. Int J Mol Sci 2022; 23:ijms23179703. [PMID: 36077101 PMCID: PMC9456144 DOI: 10.3390/ijms23179703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/19/2022] [Accepted: 08/25/2022] [Indexed: 11/23/2022] Open
Abstract
Mitochondrial epigenetic alterations are closely related to Alzheimer’s disease (AD), which is described in this review. Reports of the alteration of mitochondrial DNA (mtDNA) methylation in AD demonstrate that the disruption of the dynamic balance of mtDNA methylation and demethylation leads to damage to the mitochondrial electron transport chain and the obstruction of mitochondrial biogenesis, which is the most studied mitochondrial epigenetic change. Mitochondrial noncoding RNA modifications and the post-translational modification of mitochondrial nucleoproteins have been observed in neurodegenerative diseases and related diseases that increase the risk of AD. Although there are still relatively few mitochondrial noncoding RNA modifications and mitochondrial nuclear protein post-translational modifications reported in AD, we have reason to believe that these mitochondrial epigenetic modifications also play an important role in the AD process. This review provides a new research direction for the AD mechanism, starting from mitochondrial epigenetics. Further, this review summarizes therapeutic approaches to targeted mitochondrial epigenetics, which is the first systematic summary of therapeutic approaches in the field, including folic acid supplementation, mitochondrial-targeting antioxidants, and targeted ubiquitin-specific proteases, providing a reference for therapeutic targets for AD.
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Chen Z, Natarajan R. Epigenetic modifications in metabolic memory: What are the memories, and can we erase them? Am J Physiol Cell Physiol 2022; 323:C570-C582. [PMID: 35785987 PMCID: PMC9359656 DOI: 10.1152/ajpcell.00201.2022] [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: 05/13/2022] [Revised: 06/29/2022] [Accepted: 06/29/2022] [Indexed: 11/22/2022]
Abstract
Inherent and acquired abnormalities in gene regulation due to the influence of genetics and epigenetics (traits related to environment rather than genetic factors) underlie many diseases including diabetes. Diabetes could lead to multiple complications including retinopathy, nephropathy, and cardiovascular disease that greatly increase morbidity and mortality. Epigenetic changes have also been linked to diabetes-related complications. Genes associated with many pathophysiological features of these vascular complications (e.g., inflammation, fibrosis, and oxidative stress) can be regulated by epigenetic mechanisms involving histone posttranslational modifications, DNA methylation, changes in chromatin structure/remodeling, and noncoding RNAs. Intriguingly, these epigenetic changes triggered during early periods of hyperglycemic exposure and uncontrolled diabetes are not immediately corrected even after restoration of normoglycemia and metabolic balance. This latency in effect across time and conditions is associated with persistent development of complications in diabetes with prior history of poor glycemic control, termed as metabolic memory or legacy effect. Epigenetic modifications are generally reversible and provide a window of therapeutic opportunity to ameliorate cellular dysfunction and mitigate or "erase" metabolic memory. Notably, trained immunity and related epigenetic changes transmitted from hematopoietic stem cells to innate immune cells have also been implicated in metabolic memory. Hence, identification of epigenetic variations at candidate genes, or epigenetic signatures genome-wide by epigenome-wide association studies can aid in prompt diagnosis to prevent progression of complications and identification of much-needed new therapeutic targets. Herein, we provide a review of epigenetics and epigenomics in metabolic memory of diabetic complications covering the current basic research, clinical data, and translational implications.
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Affiliation(s)
- Zhuo Chen
- Department of Diabetes Complications and Metabolism, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, Duarte, California
| | - Rama Natarajan
- Department of Diabetes Complications and Metabolism, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, Duarte, California
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Barnstable CJ. Epigenetics and Degenerative Retinal Diseases: Prospects for New Therapeutic Approaches. Asia Pac J Ophthalmol (Phila) 2022; 11:328-334. [PMID: 36041147 DOI: 10.1097/apo.0000000000000520] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/08/2022] [Indexed: 12/26/2022] Open
Abstract
ABSTRACT There is growing evidence that retinal degenerative diseases are accompanied by epigenetic changes in both deoxyribonucleic acid methylation and histone modification. Even in the monogenic disease retinitis pigmentosa, there is a cascade of changes in gene expression that correlate with epigenetic changes, suggesting that many of the symptoms, and degenerative changes, may be a result of epigenetic changes downstream from the genetic mutation. This is supported by data from studies of diabetic retinopathy and macular degeneration, 2 diseases where it has been difficult to define a single causative change. Initial studies with modifiers of deoxyribonucleic acid methylation suggest that they can provide therapeutic benefit. A number of drugs are available to inhibit specific epigenetic histone modifier enzymes, and these offer the possibility of new therapeutic approaches to retinal disease. Systemic treatment with inhibitors of histone demethylases and histone deacetylases have arrested rod degeneration in rodent models of retinitis pigmentosa. Some evidence has suggested that similar treatments may provide benefits for patients with diabetic retinopathy. Because differentiation of retinal stem cells is regulated in part by epigenetic mechanisms, it may also be possible to direct stem cell differentiation pathways through the use of selective epigenetic modifiers. This is predicted to provide a valuable avenue to accelerate the introduction of regenerative approaches to retinal disease. Epigenetic modifiers are poised to become a powerful new approach to treat retinal degenerative diseases.
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Affiliation(s)
- Colin J Barnstable
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, PA, US
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Singh G, Storey KB. Mitochondrial DNA methyltransferases and their regulation under freezing and dehydration stresses in the freeze tolerant wood frog, Rana sylvatica. Biochem Cell Biol 2022; 100:171-178. [PMID: 35104156 DOI: 10.1139/bcb-2021-0519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Wood frogs are one of a few vertebrate species that can survive whole-body freezing. Multiple adaptations support this including cryoprotectant production (glucose), metabolic rate depression and selective changes in gene/protein expression to activate pro-survival pathways. The role of DNA methylation machinery (DNA methyltransferases, DNMTs) in regulating nuclear gene expression supporting freezing survival has already been established. However, a comparable role for DNMTs in mitochondria has not been explored in wood frogs. We examined the mitochondrial protein levels of DNMT-1, DNMT-3A, DNMT-3B and DNMT-3L as well as mitochondrial DNMT activity in the liver and heart to assess DNMT involvement in the survival of freezing and dehydration stresses (cellular dehydration being one component of freezing). Our results showed stress and tissue-specific response by mitochondrial DNMT-1 protein in liver and heart respectively. During 24h freezing and whole-body dehydration, we saw an overall downregulation of mitochondrial DNMT-1, a major protein involved in maintaining methylation levels relating to its role in selective transcription of mitochondrial genes as well as antioxidant response. Tissue-specific response of protein levels of DNMT-3A, DNMT-3B and DNMT-3L and DNMT activity in the liver suggested a preference for higher methylation state in the liver under both freezing and dehydration stresses but not in the heart.
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Affiliation(s)
- Gurjit Singh
- Carleton University Department of Biology, 120895, Biology, Ottawa, Ontario, Canada;
| | - Kenneth B Storey
- Carleton University, 6339, Biology, Department of Biology, 1125 Colonel By Drive, Ottawa, Ottawa, Ontario, Canada, K1S 5B6;
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Mohammad G, Kowluru RA. Mitochondrial Dynamics in the Metabolic Memory of Diabetic Retinopathy. J Diabetes Res 2022; 2022:3555889. [PMID: 35399705 PMCID: PMC8989559 DOI: 10.1155/2022/3555889] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 02/18/2022] [Accepted: 02/21/2022] [Indexed: 12/16/2022] Open
Abstract
Mitochondria play a central role in the development of diabetic retinopathy and in the metabolic memory associated with its continued progression. Mitochondria have a regulated fusion fission process, which is essential for their homeostasis. One of the major fission proteins, dynamin-related protein 1 (Drp1), is recruited to the mitochondria by fission protein 1 (Fis1) to initiate fragmentation. Our aim is to investigate the role of Drp1 in the altered mitochondrial dynamics in the continued progression of diabetic retinopathy. Methods. Drp1 activation, mitochondrial transport, and Drp1-Fis1 interactions were analyzed in retinal endothelial cells incubated in 20 mM glucose (HG), followed by 5 mM glucose (NG), for four days each (HG-NG group). The results were confirmed in retinal microvessels from streptozotocin-induced diabetic rats with poor glycemia (>350 mg/dl blood glucose, PC group), followed by normal glycemia (~100 mg/dl), for four months each (PC-GC group). Results. GTPase activity of Drp1, Fis1-Drp1 interactions, mitochondrial levels of Drp1, and fragmentation of the mitochondria were elevated in HG group. Mitochondrial Division Inhibitor 1 (Mdiv) or Drp1-siRNA attenuated Drp1 activation, mitochondrial fragmentation, and DNA damage. In HG-NG group, NG failed to ameliorate Drp1 activation and Drp1-Fis1 interactions, and the mitochondria remained fragmented. However, Mdiv supplementation in normal glucose, which had followed four days of high glucose (HG-NG/Mdiv group), inhibited Drp1 activation, mitochondrial fragmentation, and increase in ROS and prevented mitochondrial damage. Retinal microvessels from the rats in PC and PC-GC groups had similar Drp1 activation. Conclusion. Thus, Drp1 plays a major role in mitochondrial homeostasis in diabetic retinopathy and in the metabolic memory phenomenon associated with its continued progression. Supplementation of normal glycemia with a Drp1 inhibitor could retard development and further progression of diabetic retinopathy.
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Affiliation(s)
- Ghulam Mohammad
- Department of Ophthalmology, Visual & Anatomical Sciences, Wayne State University, Detroit, MI, USA
| | - Renu A. Kowluru
- Department of Ophthalmology, Visual & Anatomical Sciences, Wayne State University, Detroit, MI, USA
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Kowluru RA, Mohammad G. Epigenetic modifications in diabetes. Metabolism 2022; 126:154920. [PMID: 34715117 DOI: 10.1016/j.metabol.2021.154920] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 10/18/2021] [Accepted: 10/21/2021] [Indexed: 12/25/2022]
Abstract
Diabetes is now considered as a 'silent epidemic' that claims over four million lives every year, and the disease knows no socioeconomic boundaries. Despite extensive efforts by the National and International organizations, and cutting-edge research, about 11% world's population is expected to suffer from diabetes (and its complications) by year 2045. This life-long disease damages both the microvasculature and the macrovasculature of the body, and affects many metabolic and molecular pathways, altering the expression of many genes. Recent research has shown that external factors, such as environmental factors, lifestyle and pollutants can also regulate gene expression, and contribute in the disease development and progression. Many epigenetic modifications are implicated in the development of micro- and macro- vascular complications including DNA methylation and histone modifications of several genes implicated in their development. Furthermore, several noncoding RNAs, such as micro RNAs and long noncoding RNAs, are also altered, affecting many biochemical pathways. Epigenetic modifications, however, have the advantage that they could be passed to the next generation, or can be erased. They are now being explored as therapeutical target(s) in the cancer field, which opens up the possibility to use them for treating diabetes and preventing/slowing down its complications.
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Affiliation(s)
- Renu A Kowluru
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University, USA.
| | - Ghulam Mohammad
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University, USA
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Wu J, Liu LL, Cao M, Hu A, Hu D, Luo Y, Wang H, Zhong JN. DNA methylation plays important roles in retinal development and diseases. Exp Eye Res 2021; 211:108733. [PMID: 34418429 DOI: 10.1016/j.exer.2021.108733] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 12/16/2022]
Abstract
DNA methylation is important in developing and post-mitotic cells in various tissues. Recent studies have shown that DNA methylation is highly dynamic, and plays important roles during retinal development and aging. In addition, the dynamic regulation of DNA methylation is involved in the occurrence and development of age-related macular degeneration and diabetic retinopathy and shows potential in disease diagnoses and prognoses. This review introduces the epigenetic concepts of DNA methylation and demethylation with an emphasis on their regulatory roles in retinal development and related diseases. Moreover, we propose exciting ideas such as its crosstalk with other epigenetic modifications and retinal regeneration, to provide a potential direction for understanding retinal diseases from the epigenetic perspective.
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Affiliation(s)
- Jing Wu
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou, 341000, Jiangxi Province, China; Department of Ophthalmology, Lishui Municipal Central Hospital, Lishui, 323000, Zhejiang Province, China
| | - Lin-Lin Liu
- Department of Ophthalmology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, 341000, Jiangxi Province, China
| | - Miao Cao
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou, 341000, Jiangxi Province, China; Department of Ophthalmology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, 341000, Jiangxi Province, China
| | - Ang Hu
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou, 341000, Jiangxi Province, China
| | - Die Hu
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou, 341000, Jiangxi Province, China; Department of Ophthalmology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, 341000, Jiangxi Province, China
| | - Yan Luo
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou, 341000, Jiangxi Province, China
| | - Hui Wang
- Department of Ophthalmology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, 341000, Jiangxi Province, China.
| | - Jia-Ning Zhong
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou, 341000, Jiangxi Province, China.
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15
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APOBECs orchestrate genomic and epigenomic editing across health and disease. Trends Genet 2021; 37:1028-1043. [PMID: 34353635 DOI: 10.1016/j.tig.2021.07.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 07/03/2021] [Accepted: 07/05/2021] [Indexed: 12/17/2022]
Abstract
APOBEC proteins can deaminate cytosine residues in DNA and RNA. This can lead to somatic mutations, DNA breaks, RNA modifications, or DNA demethylation in a selective manner. APOBECs function in various cellular compartments and recognize different nucleic acid motifs and structures. They orchestrate a wide array of genomic and epigenomic modifications, thereby affecting various cellular functions positively or negatively, including immune editing, viral and retroelement restriction, DNA damage responses, DNA demethylation, gene expression, and tissue homeostasis. Furthermore, the cumulative increase in genomic and epigenomic editing with aging could also, at least in part, be attributed to APOBEC function. We synthesize our cumulative understanding of APOBEC activity in a unifying overview and discuss their genomic and epigenomic impact in physiological, pathological, and technological contexts.
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16
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Kim D, Sesaki H, Roy S. Reduced Levels of Drp1 Protect against Development of Retinal Vascular Lesions in Diabetic Retinopathy. Cells 2021; 10:cells10061379. [PMID: 34204906 PMCID: PMC8226547 DOI: 10.3390/cells10061379] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 05/27/2021] [Accepted: 05/27/2021] [Indexed: 12/12/2022] Open
Abstract
High glucose (HG)-induced Drp1 overexpression contributes to mitochondrial dysfunction and promotes apoptosis in retinal endothelial cells. However, it is unknown whether inhibiting Drp1 overexpression protects against the development of retinal vascular cell loss in diabetes. To investigate whether reduced Drp1 level is protective against diabetes-induced retinal vascular lesions, four groups of mice: wild type (WT) control mice, streptozotocin (STZ)-induced diabetic mice, Drp1+/− mice, and STZ-induced diabetic Drp1+/− mice were examined after 16 weeks of diabetes. Western Blot analysis indicated a significant increase in Drp1 expression in the diabetic retinas compared to those of WT mice; retinas of diabetic Drp1+/− mice showed reduced Drp1 level compared to those of diabetic mice. A significant increase in the number of acellular capillaries (AC) and pericyte loss (PL) was observed in the retinas of diabetic mice compared to those of the WT control mice. Importantly, a significant decrease in the number of AC and PL was observed in retinas of diabetic Drp1+/− mice compared to those of diabetic mice concomitant with increased expression of pro-apoptotic genes, Bax, cleaved PARP, and increased cleaved caspase-3 activity. Preventing diabetes-induced Drp1 overexpression may have protective effects against the development of vascular lesions, characteristic of diabetic retinopathy.
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Affiliation(s)
- Dongjoon Kim
- Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA;
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA;
| | - Sayon Roy
- Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA;
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA 02118, USA
- Correspondence: ; Tel.: +1-617-358-6801
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17
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Doblado L, Lueck C, Rey C, Samhan-Arias AK, Prieto I, Stacchiotti A, Monsalve M. Mitophagy in Human Diseases. Int J Mol Sci 2021; 22:ijms22083903. [PMID: 33167334 PMCID: PMC8069949 DOI: 10.3390/ijms22083903] [Citation(s) in RCA: 101] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 02/06/2023] Open
Abstract
Mitophagy is a selective autophagic process, essential for cellular homeostasis, that eliminates dysfunctional mitochondria. Activated by inner membrane depolarization, it plays an important role during development and is fundamental in highly differentiated post-mitotic cells that are highly dependent on aerobic metabolism, such as neurons, muscle cells, and hepatocytes. Both defective and excessive mitophagy have been proposed to contribute to age-related neurodegenerative diseases, such as Parkinson’s and Alzheimer’s diseases, metabolic diseases, vascular complications of diabetes, myocardial injury, muscle dystrophy, and liver disease, among others. Pharmacological or dietary interventions that restore mitophagy homeostasis and facilitate the elimination of irreversibly damaged mitochondria, thus, could serve as potential therapies in several chronic diseases. However, despite extraordinary advances in this field, mainly derived from in vitro and preclinical animal models, human applications based on the regulation of mitochondrial quality in patients have not yet been approved. In this review, we summarize the key selective mitochondrial autophagy pathways and their role in prevalent chronic human diseases and highlight the potential use of specific interventions.
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Affiliation(s)
- Laura Doblado
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain; (L.D.); (C.L.); (C.R.)
| | - Claudia Lueck
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain; (L.D.); (C.L.); (C.R.)
| | - Claudia Rey
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain; (L.D.); (C.L.); (C.R.)
| | - Alejandro K. Samhan-Arias
- Department of Biochemistry, Universidad Autónoma de Madrid e Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain;
| | - Ignacio Prieto
- Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, Isaac Peral 42, 28015 Madrid, Spain;
| | - Alessandra Stacchiotti
- Department of Biomedical Sciences for Health, Universita’ Degli Studi di Milano, Via Mangiagalli 31, 20133 Milan, Italy
- U.O. Laboratorio di Morfologia Umana Applicata, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy
- Correspondence: (A.S.); (M.M.)
| | - Maria Monsalve
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain; (L.D.); (C.L.); (C.R.)
- Correspondence: (A.S.); (M.M.)
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Abstract
The increasing prevalence of non-alcoholic fatty liver disease (NAFLD) poses a growing challenge in terms of its prevention and treatment. The 'multiple hits' hypothesis of multiple insults, such as dietary fat intake, de novo lipogenesis, insulin resistance, oxidative stress, mitochondrial dysfunction, gut dysbiosis and hepatic inflammation, can provide a more accurate explanation of the pathogenesis of NAFLD. Betaine plays important roles in regulating the genes associated with NAFLD through anti-inflammatory effects, increased free fatty oxidation, anti-lipogenic effects and improved insulin resistance and mitochondrial function; however, the mechanism of betaine remains elusive.
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19
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Snyder RJ, Kleeberger SR. Role of Mitochondrial DNA in Inflammatory Airway Diseases. Compr Physiol 2021; 11:1485-1499. [PMID: 33577124 DOI: 10.1002/cphy.c200010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The mitochondrial genome is a small, circular, and highly conserved piece of DNA which encodes only 13 protein subunits yet is vital for electron transport in the mitochondrion and, therefore, vital for the existence of multicellular life on Earth. Despite this importance, mitochondrial DNA (mtDNA) is located in one of the least-protected areas of the cell, exposing it to high concentrations of intracellular reactive oxygen species (ROS) and threat from exogenous substances and pathogens. Until recently, the quality control mechanisms which ensured the stability of the nuclear genome were thought to be minimal or nonexistent in the mitochondria, and the thousands of redundant copies of mtDNA in each cell were believed to be the primary mechanism of protecting these genes. However, a vast network of mechanisms has been discovered that repair mtDNA lesions, replace and recycle mitochondrial chromosomes, and conduct alternate RNA processing for previously undescribed mitochondrial proteins. New mtDNA/RNA-dependent signaling pathways reveal a mostly undiscovered biochemical landscape in which the mitochondria interface with their host cells/organisms. As the myriad ways in which the function of the mitochondrial genome can affect human health have become increasingly apparent, the use of mitogenomic biomarkers (such as copy number and heteroplasmy) as toxicological endpoints has become more widely accepted. In this article, we examine several pathologies of human airway epithelium, including particle exposures, inflammatory diseases, and hyperoxia, and discuss the role of mitochondrial genotoxicity in the pathogenesis and/or exacerbation of these conditions. © 2021 American Physiological Society. Compr Physiol 11:1485-1499, 2021.
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Affiliation(s)
- Ryan J Snyder
- National Institute of Environmental Health Sciences, NIH, Durham, North Carolina, USA
| | - Steven R Kleeberger
- National Institute of Environmental Health Sciences, NIH, Durham, North Carolina, USA
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20
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Xiang H, Song R, Ouyang J, Zhu R, Shu Z, Liu Y, Wang X, Zhang D, Zhao J, Lu H. Organelle dynamics of endothelial mitochondria in diabetic angiopathy. Eur J Pharmacol 2021; 895:173865. [PMID: 33460616 DOI: 10.1016/j.ejphar.2021.173865] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 12/22/2020] [Accepted: 01/11/2021] [Indexed: 12/19/2022]
Abstract
Diabetes, a chronic non-communicable disease, has become one of the most serious and critical public health problems with increasing incidence trends. Chronic vascular complications are the major causes of disability and death in diabetic patients with endothelial dysfunction. Diabetes is intimately associated with endothelial mitochondrial dysfunction, indicated by increased oxidative stress, decreased biogenesis, increased DNA damage, and weakened autophagy in mitochondria. All these morphological and functional changes of mitochondria play important roles in diabetic endothelial dysfunction. Herein, we reviewed the roles and mechanisms of endothelial mitochondrial dysfunction, particularly mitochondrial dynamics in the vascular complications of diabetes and summarized the potential mitochondria-targeted therapies in diabetic vascular complications.
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Affiliation(s)
- Hong Xiang
- Center for Experimental Medical Research, the Third Xiangya Hospital of Central South University, Changsha, Hunan, 410013, China
| | - Ruipeng Song
- Department of Endocrinology, The Third People's Provincial Hospital of Henan Province, Zhengzhou, 450000, Henan, China
| | - Jie Ouyang
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, Hunan, 410013, China
| | - Ruifang Zhu
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Zhihao Shu
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, Hunan, 410013, China
| | - Yulan Liu
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, Hunan, 410013, China
| | - Xuewen Wang
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, Hunan, 410013, China
| | - Dongtao Zhang
- Department of Geriatrics, Tongxu Hospital of Traditional Chinese Medicine, Kaifeng, Henan, 475400, China
| | - Jiangwei Zhao
- Department of Internal Medicine 3, People's Hospital of Weihui, Xinxiang, Henan, 453100, China
| | - Hongwei Lu
- Center for Experimental Medical Research, the Third Xiangya Hospital of Central South University, Changsha, Hunan, 410013, China.
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21
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Kang Q, Yang C. Oxidative stress and diabetic retinopathy: Molecular mechanisms, pathogenetic role and therapeutic implications. Redox Biol 2020; 37:101799. [PMID: 33248932 PMCID: PMC7767789 DOI: 10.1016/j.redox.2020.101799] [Citation(s) in RCA: 416] [Impact Index Per Article: 104.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/29/2020] [Accepted: 11/10/2020] [Indexed: 12/18/2022] Open
Abstract
Oxidative stress, a cytopathic outcome of excessive generation of ROS and the repression of antioxidant defense system for ROS elimination, is involved in the pathogenesis of multiple diseases, including diabetes and its complications. Retinopathy, a microvascular complication of diabetes, is the primary cause of acquired blindness in diabetic patients. Oxidative stress has been verified as one critical contributor to the pathogenesis of diabetic retinopathy. Oxidative stress can both contribute to and result from the metabolic abnormalities induced by hyperglycemia, mainly including the increased flux of the polyol pathway and hexosamine pathway, the hyper-activation of protein kinase C (PKC) isoforms, and the accumulation of advanced glycation end products (AGEs). Moreover, the repression of the antioxidant defense system by hyperglycemia-mediated epigenetic modification also leads to the imbalance between the scavenging and production of ROS. Excessive accumulation of ROS induces mitochondrial damage, cellular apoptosis, inflammation, lipid peroxidation, and structural and functional alterations in retina. Therefore, it is important to understand and elucidate the oxidative stress-related mechanisms underlying the progress of diabetic retinopathy. In addition, the abnormalities correlated with oxidative stress provide multiple potential therapeutic targets to develop safe and effective treatments for diabetic retinopathy. Here, we also summarized the main antioxidant therapeutic strategies to control this disease. Oxidative stress can both contribute to and result from hyperglycemia-induced metabolic abnormalities in retina. Genes important in regulation of ROS are epigenetically modified, increasing ROS accumulation in retina. Oxidative stress is closely associated with the pathological changes in the progress of diabetic retinopathy. Antioxidants ameliorate retinopathy through targeting multiple steps of oxidative stress.
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Affiliation(s)
- Qingzheng Kang
- Institute for Advanced Study, Shenzhen University, Nanshan District, Shenzhen, 518060, China; Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Chunxue Yang
- Department of Pathology, The University of Hong Kong, Hong Kong SAR, 999077, China.
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22
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Liu H, Zhang H, Zhang Y, Xu S, Zhao H, He H, Liu X. Modeling mtDNA hypermethylation vicious circle mediating Aβ-induced endothelial damage memory in HCMEC/D3 cell. Aging (Albany NY) 2020; 12:18343-18362. [PMID: 32986015 PMCID: PMC7585070 DOI: 10.18632/aging.103699] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 07/06/2020] [Indexed: 01/24/2023]
Abstract
It is well accepted that accumulation of beta-amyloid (Aβ) may involve in endothelial dysfunction during the Alzheimer's disease (AD) progression. However, cerebrovascular function cannot be improved by removing Aβ in AD animal models. The reasons for these paradoxical results still remain to be further investigated. We hypothesize that Aβ exposure may cause persistence damage to cerebral endothelial cell even after Aβ is removed (termed as cerebrovascular endothelial damage memory) mitochondria DNA (mtDNA) hypermethylation is assumed to be involved in this process. The aim of this study is to investigate whether Aβ exposure induces cerebrovascular endothelial damage memory in endothelial cells and mtDNA hypermethylation involves in this process. The hCMEC/D3 cell is treated with Aβ1-42 for 12h and then withdraw Aβ1-42 for another 12h incubation to investigate whether cerebrovascular endothelial damage memory exists in endothelial cells. The levels of mtDNA methylation and cell vitality were not improved by removing Aβ1-42 after 12h Aβ1-42 incubation which suggested that the cerebrovascular endothelial damage memory may exist in endothelial cells. Kinetics model analysis suggested that mtDNA hypermethylation involves in initiating the cerebrovascular endothelial damage memory otherwise α-oxoglutarate (AKG) exhaustion plays a vital role in maintaining this process. DNA methylation inhibitor decitabine and AKG supplement may relieve the cerebrovascular endothelial damage memory dose dependently. This study provides a novel feature of cerebrovascular endothelial damage induced by Aβ.
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Affiliation(s)
- HaoChen Liu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Hong Zhang
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Yixuan Zhang
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Sheng Xu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Huimin Zhao
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Hua He
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - XiaoQuan Liu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
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23
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Diabetic Retinopathy: The Role of Mitochondria in the Neural Retina and Microvascular Disease. Antioxidants (Basel) 2020; 9:antiox9100905. [PMID: 32977483 PMCID: PMC7598160 DOI: 10.3390/antiox9100905] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/11/2022] Open
Abstract
Diabetic retinopathy (DR), a common chronic complication of diabetes mellitus and the leading cause of vision loss in the working-age population, is clinically defined as a microvascular disease that involves damage of the retinal capillaries with secondary visual impairment. While its clinical diagnosis is based on vascular pathology, DR is associated with early abnormalities in the electroretinogram, indicating alterations of the neural retina and impaired visual signaling. The pathogenesis of DR is complex and likely involves the simultaneous dysregulation of multiple metabolic and signaling pathways through the retinal neurovascular unit. There is evidence that microvascular disease in DR is caused in part by altered energetic metabolism in the neural retina and specifically from signals originating in the photoreceptors. In this review, we discuss the main pathogenic mechanisms that link alterations in neural retina bioenergetics with vascular regression in DR. We focus specifically on the recent developments related to alterations in mitochondrial metabolism including energetic substrate selection, mitochondrial function, oxidation-reduction (redox) imbalance, and oxidative stress, and critically discuss the mechanisms of these changes and their consequences on retinal function. We also acknowledge implications for emerging therapeutic approaches and future research directions to find novel mitochondria-targeted therapeutic strategies to correct bioenergetics in diabetes. We conclude that retinal bioenergetics is affected in the early stages of diabetes with consequences beyond changes in ATP content, and that maintaining mitochondrial integrity may alleviate retinal disease.
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López-Contreras AK, Martínez-Ruiz MG, Olvera-Montaño C, Robles-Rivera RR, Arévalo-Simental DE, Castellanos-González JA, Hernández-Chávez A, Huerta-Olvera SG, Cardona-Muñoz EG, Rodríguez-Carrizalez AD. Importance of the Use of Oxidative Stress Biomarkers and Inflammatory Profile in Aqueous and Vitreous Humor in Diabetic Retinopathy. Antioxidants (Basel) 2020; 9:antiox9090891. [PMID: 32962301 PMCID: PMC7555116 DOI: 10.3390/antiox9090891] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 09/03/2020] [Accepted: 09/10/2020] [Indexed: 12/23/2022] Open
Abstract
Diabetic retinopathy is one of the leading causes of visual impairment and morbidity worldwide, being the number one cause of blindness in people between 27 and 75 years old. It is estimated that ~191 million people will be diagnosed with this microvascular complication by 2030. Its pathogenesis is due to alterations in the retinal microvasculature as a result of a high concentration of glucose in the blood for a long time which generates numerous molecular changes like oxidative stress. Therefore, this narrative review aims to approach various biomarkers associated with the development of diabetic retinopathy. Focusing on the molecules showing promise as detection tools, among them we consider markers of oxidative stress (TAC, LPO, MDA, 4-HNE, SOD, GPx, and catalase), inflammation (IL-6, IL-1ß, IL-8, IL-10, IL-17A, TNF-α, and MMPs), apoptosis (NF-kB, cyt-c, and caspases), and recently those that have to do with epigenetic modifications, their measurement in different biological matrices obtained from the eye, including importance, obtaining process, handling, and storage of these matrices in order to have the ability to detect the disease in its early stages.
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Affiliation(s)
- Ana Karen López-Contreras
- Department of Physiology, Health Sciences University Center, Institute of Clinical and Experimental Therapeutics, University of Guadalajara, Guadalajara, Jalisco 44340, Mexico; (A.K.L.-C.); (M.G.M.-R.); (C.O.-M.); (R.R.R.-R.); (D.E.A.-S.); (J.A.C.-G.); (A.H.-C.); (E.G.C.-M.)
| | - María Guadalupe Martínez-Ruiz
- Department of Physiology, Health Sciences University Center, Institute of Clinical and Experimental Therapeutics, University of Guadalajara, Guadalajara, Jalisco 44340, Mexico; (A.K.L.-C.); (M.G.M.-R.); (C.O.-M.); (R.R.R.-R.); (D.E.A.-S.); (J.A.C.-G.); (A.H.-C.); (E.G.C.-M.)
| | - Cecilia Olvera-Montaño
- Department of Physiology, Health Sciences University Center, Institute of Clinical and Experimental Therapeutics, University of Guadalajara, Guadalajara, Jalisco 44340, Mexico; (A.K.L.-C.); (M.G.M.-R.); (C.O.-M.); (R.R.R.-R.); (D.E.A.-S.); (J.A.C.-G.); (A.H.-C.); (E.G.C.-M.)
| | - Ricardo Raúl Robles-Rivera
- Department of Physiology, Health Sciences University Center, Institute of Clinical and Experimental Therapeutics, University of Guadalajara, Guadalajara, Jalisco 44340, Mexico; (A.K.L.-C.); (M.G.M.-R.); (C.O.-M.); (R.R.R.-R.); (D.E.A.-S.); (J.A.C.-G.); (A.H.-C.); (E.G.C.-M.)
| | - Diana Esperanza Arévalo-Simental
- Department of Physiology, Health Sciences University Center, Institute of Clinical and Experimental Therapeutics, University of Guadalajara, Guadalajara, Jalisco 44340, Mexico; (A.K.L.-C.); (M.G.M.-R.); (C.O.-M.); (R.R.R.-R.); (D.E.A.-S.); (J.A.C.-G.); (A.H.-C.); (E.G.C.-M.)
- Department of Ophthalmology, Hospital Civil de Guadalajara “Fray Antonio Alcalde”, Guadalajara, Jalisco 44280, Mexico
| | - José Alberto Castellanos-González
- Department of Physiology, Health Sciences University Center, Institute of Clinical and Experimental Therapeutics, University of Guadalajara, Guadalajara, Jalisco 44340, Mexico; (A.K.L.-C.); (M.G.M.-R.); (C.O.-M.); (R.R.R.-R.); (D.E.A.-S.); (J.A.C.-G.); (A.H.-C.); (E.G.C.-M.)
- Department of Ophthalmology, Specialties Hospital of the National Occidental Medical Center, Mexican Institute of Social Security, Guadalajara, Jalisco 44329, Mexico
| | - Abel Hernández-Chávez
- Department of Physiology, Health Sciences University Center, Institute of Clinical and Experimental Therapeutics, University of Guadalajara, Guadalajara, Jalisco 44340, Mexico; (A.K.L.-C.); (M.G.M.-R.); (C.O.-M.); (R.R.R.-R.); (D.E.A.-S.); (J.A.C.-G.); (A.H.-C.); (E.G.C.-M.)
| | - Selene Guadalupe Huerta-Olvera
- Medical and Life Sciences Department, La Ciénega University Center, University of Guadalajara, Ocotlán, Jalisco 47810, Mexico;
| | - Ernesto German Cardona-Muñoz
- Department of Physiology, Health Sciences University Center, Institute of Clinical and Experimental Therapeutics, University of Guadalajara, Guadalajara, Jalisco 44340, Mexico; (A.K.L.-C.); (M.G.M.-R.); (C.O.-M.); (R.R.R.-R.); (D.E.A.-S.); (J.A.C.-G.); (A.H.-C.); (E.G.C.-M.)
| | - Adolfo Daniel Rodríguez-Carrizalez
- Department of Physiology, Health Sciences University Center, Institute of Clinical and Experimental Therapeutics, University of Guadalajara, Guadalajara, Jalisco 44340, Mexico; (A.K.L.-C.); (M.G.M.-R.); (C.O.-M.); (R.R.R.-R.); (D.E.A.-S.); (J.A.C.-G.); (A.H.-C.); (E.G.C.-M.)
- Correspondence:
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25
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Epigenetic Clock: DNA Methylation in Aging. Stem Cells Int 2020; 2020:1047896. [PMID: 32724310 PMCID: PMC7366189 DOI: 10.1155/2020/1047896] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/11/2020] [Accepted: 06/20/2020] [Indexed: 02/07/2023] Open
Abstract
Aging, which is accompanied by decreased organ function and increased disease incidence, limits human lifespan and has attracted investigators for thousands of years. In recent decades, with the rapid development of biology, scientists have shown that epigenetic modifications, especially DNA methylation, are key regulators involved in this process. Regular fluctuations in global DNA methylation levels have been shown to accurately estimate biological age and disease prognosis. In this review, we discuss recent findings regarding the relationship between variations in DNA methylation level patterns and aging. In addition, we introduce the known mechanisms by which DNA methylation regulators affect aging and related diseases. As more studies uncover the mechanisms by which DNA methylation regulates aging, antiaging interventions and treatments for related diseases may be developed that enable human life extension.
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Kowluru RA, Mohammad G. Epigenetics and Mitochondrial Stability in the Metabolic Memory Phenomenon Associated with Continued Progression of Diabetic Retinopathy. Sci Rep 2020; 10:6655. [PMID: 32313015 PMCID: PMC7171070 DOI: 10.1038/s41598-020-63527-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/20/2020] [Indexed: 02/07/2023] Open
Abstract
Retinopathy continues to progress even when diabetic patients try to control their blood sugar, but the molecular mechanism of this 'metabolic memory' phenomenon remains elusive. Retinal mitochondria remain damaged and vicious cycle of free radicals continues to self-propagate. DNA methylation suppresses gene expression, and diabetes activates DNA methylation machinery. Our aim was to investigate the role of DNA methylation in continued compromised mitochondrial dynamics and genomic stability in diabetic retinopathy. Using retinal endothelial cells, incubated in 20 mM glucose for four days, followed by 5 mM glucose for four days, and retinal microvessels from streptozotocin-induced diabetic rats in poor glycemia for four months, followed by normal glycemia for four additional months, DNA methylation of mitochondrial fusion and mismatch repair proteins, Mfn2 and Mlh1 respectively, was determined. Retinopathy was detected in trypsin-digested microvasculature. Re-institution of good glycemia had no beneficial effect on hypermethylation of Mfn2 and Mlh1 and retinal function (electroretinogram), and the retinopathy continued to progress. However, intervention of good glycemia directly with DNA methylation inhibitors (Azacytidine or Dnmt1-siRNA), prevented Mfn2 and Mlh1 hypermethylation, and ameliorated retinal dysfunction and diabetic retinopathy. Thus, direct regulation of DNA methylation can prevent/reverse diabetic retinopathy by maintaining mitochondrial dynamics and DNA stability, and prevent retinal functional damage.
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MESH Headings
- Animals
- Azacitidine/pharmacology
- Cell Line
- DNA (Cytosine-5-)-Methyltransferase 1/antagonists & inhibitors
- DNA (Cytosine-5-)-Methyltransferase 1/genetics
- DNA (Cytosine-5-)-Methyltransferase 1/metabolism
- DNA Methylation
- DNA, Mitochondrial/genetics
- DNA, Mitochondrial/metabolism
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Experimental/therapy
- Diabetic Retinopathy/chemically induced
- Diabetic Retinopathy/genetics
- Diabetic Retinopathy/pathology
- Diabetic Retinopathy/therapy
- Disease Progression
- Electroretinography
- Endothelial Cells/drug effects
- Endothelial Cells/metabolism
- Endothelial Cells/pathology
- Epigenesis, Genetic
- GTP Phosphohydrolases/genetics
- GTP Phosphohydrolases/metabolism
- Glucose/adverse effects
- Humans
- Hyperglycemia/chemically induced
- Hyperglycemia/genetics
- Hyperglycemia/pathology
- Hyperglycemia/therapy
- Male
- Mitochondria/drug effects
- Mitochondria/genetics
- Mitochondria/metabolism
- Mitochondria/pathology
- MutL Protein Homolog 1/genetics
- MutL Protein Homolog 1/metabolism
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Rats
- Rats, Wistar
- Retina/drug effects
- Retina/metabolism
- Retina/pathology
- Signal Transduction
- Streptozocin/administration & dosage
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Affiliation(s)
- Renu A Kowluru
- Kresge Eye Institute, Wayne State University, Detroit, MI, USA.
| | - Ghulam Mohammad
- Kresge Eye Institute, Wayne State University, Detroit, MI, USA
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27
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Kowluru RA. Retinopathy in a Diet-Induced Type 2 Diabetic Rat Model and Role of Epigenetic Modifications. Diabetes 2020; 69:689-698. [PMID: 31949005 PMCID: PMC7085254 DOI: 10.2337/db19-1009] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 01/08/2020] [Indexed: 12/12/2022]
Abstract
Type 2 diabetes accounts for 90% of the population with diabetes, and these patients are generally obese and hyperlipidemic. In addition to hyperglycemia, hyperlipidemia is also closely related with diabetic retinopathy. The aim was to investigate retinopathy in a model closely mimicking the normal progression and metabolic features of the population with type 2 diabetes and elucidate the molecular mechanism. Retinopathy was evaluated in rats fed a 45% kcal as fat diet for 8 weeks before administering streptozotocin, 30 mg/kg body weight (T2D), and compared with age- and duration-matched type 1 diabetic rats (T1D) (60 mg/kg streptozotocin). The role of epigenetic modifications in mitochondrial damage was evaluated in retinal microvasculature. T2D rats were obese and severely hyperlipidemic, with impaired glucose and insulin tolerance compared with age-matched T1D rats. While at 4 months of diabetes, T1D rats had no detectable retinopathy, T2D rats had significant retinopathy, their mitochondrial copy numbers were lower, and mtDNA and Rac1 promoter DNA methylation was exacerbated. At 6 months, retinopathy was comparable in T2D and T1D rats, suggesting that obesity exaggerates hyperglycemia-induced epigenetic modifications, accelerating mitochondrial damage and diabetic retinopathy. Thus, maintenance of good lifestyle and BMI could be beneficial in regulating epigenetic modifications and preventing/retarding retinopathy in patients with diabetes.
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MESH Headings
- Animals
- DNA Methylation
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Type 2/etiology
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/metabolism
- Diabetic Retinopathy/genetics
- Diabetic Retinopathy/metabolism
- Diet, High-Fat/adverse effects
- Disease Models, Animal
- Epigenesis, Genetic
- Insulin Resistance/physiology
- Male
- Promoter Regions, Genetic
- Rats
- Rats, Sprague-Dawley
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Affiliation(s)
- Renu A Kowluru
- Kresge Eye Institute, Wayne State University, Detroit, MI
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28
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Mohammed SA, Ambrosini S, Lüscher T, Paneni F, Costantino S. Epigenetic Control of Mitochondrial Function in the Vasculature. Front Cardiovasc Med 2020; 7:28. [PMID: 32195271 PMCID: PMC7064473 DOI: 10.3389/fcvm.2020.00028] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/19/2020] [Indexed: 12/24/2022] Open
Abstract
The molecular signatures of epigenetic regulation and chromatin architecture are emerging as pivotal regulators of mitochondrial function. Recent studies unveiled a complex intersection among environmental factors, epigenetic signals, and mitochondrial metabolism, ultimately leading to alterations of vascular phenotype and increased cardiovascular risk. Changing environmental conditions over the lifetime induce covalent and post-translational chemical modification of the chromatin template which sensitize the genome to establish new transcriptional programs and, hence, diverse functional states. On the other hand, metabolic alterations occurring in mitochondria affect the availability of substrates for chromatin-modifying enzymes, thus leading to maladaptive epigenetic signatures altering chromatin accessibility and gene transcription. Indeed, several components of the epigenetic machinery require intermediates of cellular metabolism (ATP, AcCoA, NADH, α-ketoglutarate) for enzymatic function. In the present review, we describe the emerging role of epigenetic modifications as fine tuners of gene transcription in mitochondrial dysfunction and vascular disease. Specifically, the following aspects are described in detail: (i) mitochondria and vascular function, (ii) mitochondrial ROS, (iii) epigenetic regulation of mitochondrial function; (iv) the role of mitochondrial metabolites as key effectors for chromatin-modifying enzymes; (v) epigenetic therapies. Understanding epigenetic routes may pave the way for new approaches to develop personalized therapies to prevent mitochondrial insufficiency and its complications.
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Affiliation(s)
- Shafeeq A Mohammed
- Center for Molecular Cardiology, University of Zürich, Zurich, Switzerland
| | - Samuele Ambrosini
- Center for Molecular Cardiology, University of Zürich, Zurich, Switzerland
| | - Thomas Lüscher
- Center for Molecular Cardiology, University of Zürich, Zurich, Switzerland.,Research, Education and Development, Royal Brompton and Harefield Hospital Trust and Imperial College, London, United Kingdom
| | - Francesco Paneni
- Center for Molecular Cardiology, University of Zürich, Zurich, Switzerland.,Department of Cardiology, University Heart Center, University Hospital Zurich, Zurich, Switzerland.,Department of Research and Education, University Hospital Zurich, Zurich, Switzerland
| | - Sarah Costantino
- Center for Molecular Cardiology, University of Zürich, Zurich, Switzerland
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29
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Dolinko AH, Chwa M, Atilano SR, Kenney MC. African and Asian Mitochondrial DNA Haplogroups Confer Resistance Against Diabetic Stresses on Retinal Pigment Epithelial Cybrid Cells In Vitro. Mol Neurobiol 2020; 57:1636-1655. [PMID: 31811564 PMCID: PMC7123578 DOI: 10.1007/s12035-019-01834-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 11/12/2019] [Indexed: 01/09/2023]
Abstract
Diabetic retinopathy (DR) is the most common cause of blindness for individuals under the age of 65. This loss of vision can be due to ischemia, neovascularization, and/or diabetic macular edema, which are caused by breakdown of the blood-retina barrier at the level of the retinal pigment epithelium (RPE) and inner retinal vasculature. The prevalence of diabetes and its complications differ between Caucasian-Americans and certain minority populations, such as African-Americans and Asian-Americans. Individuals can be classified by their mitochondrial haplogroups, which are collections of single nucleotide polymorphisms (SNPs) in mitochondrial DNA (mtDNA) representing ancient geographic origins of populations. In this study, we compared the responses of diabetic human RPE cybrids, cell lines containing identical nuclei but mitochondria from either European (maternal European) or maternal African or Asian individuals, to hypoxia and high glucose levels. The African and Asian diabetic ([Afr+Asi]/DM) cybrids showed (1) resistance to both hyperglycemic and hypoxic stresses; (2) downregulation of pro-apoptotic indicator BAX; (3) upregulation of DNA methylation genes, such as DNMT3A and DNMT3B; and (4) resistance to DNA demethylation by the methylation inhibitor 5-Aza-2'-deoxycytidine (5-Aza-dC) compared to European diabetic (Euro/DM) cybrids. Our findings suggest that mitochondria from African and Asian diabetic subjects possess a "metabolic memory" that confers resistance against hyperglycemia, hypoxia, and demethylation, and that this "metabolic memory" can be transferred into the RPE cybrid cell lines in vitro.
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Affiliation(s)
- Andrew H Dolinko
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, 92697, USA
- Department of Ophthalmology Research, Gavin Herbert Eye Institute, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Road, Irvine, CA, 92697, USA
| | - Marilyn Chwa
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, 92697, USA
| | - Shari R Atilano
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, 92697, USA
| | - M Cristina Kenney
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, 92697, USA.
- Department of Ophthalmology Research, Gavin Herbert Eye Institute, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Road, Irvine, CA, 92697, USA.
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30
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Thioredoxin-Interacting Protein (TXNIP) Regulates Parkin/PINK1-mediated Mitophagy in Dopaminergic Neurons Under High-glucose Conditions: Implications for Molecular Links Between Parkinson's Disease and Diabetes. Neurosci Bull 2020; 36:346-358. [PMID: 31939095 DOI: 10.1007/s12264-019-00459-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 12/06/2019] [Indexed: 12/30/2022] Open
Abstract
Patients with diabetes mellitus have a higher risk of developing Parkinson's disease (PD). However, the molecular links between PD and diabetes remain unclear. In this study, we investigated the roles of thioredoxin-interacting protein (TXNIP) in Parkin/PINK1-mediated mitophagy in dopaminergic (DA) cells under high-glucose (HG) conditions. In streptozotocin-induced diabetic mice, TXNIP was upregulated and autophagy was inhibited in the midbrain, while the loss of DA neurons was accelerated by hyperglycemia. In cultured PC12 cells under HG, TXNIP expression was upregulated and the intracellular reactive oxygen species (ROS) levels increased, leading to cell death. Autophagic flux was further blocked and PINK1 expression was decreased under HG conditions. Parkin expression in the mitochondrial fraction and carbonyl cyanide 3-chlorophenylhydrazone (CCCP)-induced co-localization of COX IV (marker for mitochondria) and LAMP1 (marker for lysosomes) were also significantly decreased by HG. Overexpression of TXNIP was sufficient to decrease the expression of both PINK1 and Parkin in PC12 cells, while knockdown of the expression of TXNIP by siRNA decreased intracellular ROS and attenuated cellular injury under HG. Moreover, inhibition of TXNIP improved the CCCP-induced co-localization of COX IV and LAMP1 in PC12 cells under HG. Together, these results suggest that TXNIP regulates Parkin/PINK1-mediated mitophagy under HG conditions, and targeting TXNIP may be a promising therapeutic strategy for reducing the risk of PD under hyperglycemic conditions.
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31
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Mohammad G, Radhakrishnan R, Kowluru RA. Epigenetic Modifications Compromise Mitochondrial DNA Quality Control in the Development of Diabetic Retinopathy. Invest Ophthalmol Vis Sci 2020; 60:3943-3951. [PMID: 31546260 PMCID: PMC6759036 DOI: 10.1167/iovs.19-27602] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Purpose Diabetes causes dysfunction in the retinal mitochondria and increases base mismatches in their DNA (mtDNA). The enzyme responsible for repairing the base mismatches, MutL homolog 1 (Mlh1), is compromised. Diabetes also favors many epigenetic modifications and activates DNA methylation machinery, and Mlh1 has a CpG-rich promoter. Our aim is to identify the molecular mechanism responsible for impaired mtDNA mismatch repair in the pathogenesis of diabetic retinopathy. Methods Human retinal endothelial cells, incubated in 20 mM glucose, were analyzed for mitochondrial localization of Mlh1 by an immunofluorescence technique, Mlh1 promoter DNA methylation by the methylated DNA capture method, and the binding of Dnmt1 and transcriptional factor Sp1 by chromatin immunoprecipitation. The results were confirmed in retinal microvessels from streptozotocin-induced diabetic mice, with or without Dnmt inhibitors, and from human donors with diabetic retinopathy. Results Compared with cells in 5 mM glucose, high glucose decreased Mlh1 mitochondrial localization, and its promoter DNA was hypermethylated with increased Dnmt-1 binding and decreased Sp1 binding. Dnmt inhibitors attenuated Mlh1 promoter hypermethylation and prevented a decrease in its gene transcripts and an increase in mtDNA mismatches. The administration of Dnmt inhibitors in mice ameliorated a diabetes-induced increase in Mlh1 promoter hypermethylation and a decrease in its gene transcripts. Similar decreases in Mlh1 gene transcripts and its promoter DNA hypermethylation were observed in human donors. Conclusions Thus, as a result of the epigenetic modifications of the Mlh1 promoter, its transcription is decreased, and decreased mitochondrial accumulation fails to repair mtDNA mismatches. Therapies targeted to halt DNA methylation have the potential to prevent/halt mtDNA damage and the development of diabetic retinopathy.
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Affiliation(s)
- Ghulam Mohammad
- Department of Ophthalmology, Visual & Anatomical Sciences, Wayne State University, Detroit, Michigan, United States
| | - Rakesh Radhakrishnan
- Department of Ophthalmology, Visual & Anatomical Sciences, Wayne State University, Detroit, Michigan, United States
| | - Renu A Kowluru
- Department of Ophthalmology, Visual & Anatomical Sciences, Wayne State University, Detroit, Michigan, United States
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32
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Ferrington DA, Fisher CR, Kowluru RA. Mitochondrial Defects Drive Degenerative Retinal Diseases. Trends Mol Med 2020; 26:105-118. [PMID: 31771932 PMCID: PMC6938541 DOI: 10.1016/j.molmed.2019.10.008] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/16/2019] [Accepted: 10/23/2019] [Indexed: 01/08/2023]
Abstract
Mitochondrial dysfunction is involved in the pathology of two major blinding retinal diseases, diabetic retinopathy (DR) and age-related macular degeneration (AMD). These diseases accumulate mitochondrial defects in distinct retinal subcellular structures, the vascular/neural network in DR and the retinal pigment epithelium (RPE) in AMD. These mitochondrial defects cause a metabolic crisis that drives disease. With no treatments to stop these diseases, coupled with an increasing population suffering from AMD and DR, there is an urgent need to develop new therapeutics targeting the mitochondria to prevent or reverse disease-specific pathology.
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Affiliation(s)
- Deborah A Ferrington
- Department of Ophthalmology and Visual Neurosciences and Graduate Program in Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.
| | - Cody R Fisher
- Department of Ophthalmology and Visual Neurosciences and Graduate Program in Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Renu A Kowluru
- Ophthalmology, Vision, and Anatomical Sciences, Wayne State University, Detroit, MI, USA.
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33
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Wang(a) J, Wang S, Wang(b) J, Xiao M, Guo Y, Tang Y, Zhang J, Gu J. Epigenetic Regulation Associated With Sirtuin 1 in Complications of Diabetes Mellitus. Front Endocrinol (Lausanne) 2020; 11:598012. [PMID: 33537003 PMCID: PMC7848207 DOI: 10.3389/fendo.2020.598012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 11/27/2020] [Indexed: 01/19/2023] Open
Abstract
Diabetes mellitus (DM) has been one of the largest health concerns of the 21st century due to the serious complications associated with the disease. Therefore, it is essential to investigate the pathogenesis of DM and develop novel strategies to reduce the burden of diabetic complications. Sirtuin 1 (SIRT1), a nicotinamide adenosine dinucleotide (NAD+)-dependent deacetylase, has been reported to not only deacetylate histones to modulate chromatin function but also deacetylate numerous transcription factors to regulate the expression of target genes, both positively and negatively. SIRT1 also plays a crucial role in regulating histone and DNA methylation through the recruitment of other nuclear enzymes to the chromatin. Furthermore, SIRT1 has been verified as a direct target of many microRNAs (miRNAs). Recently, numerous studies have explored the key roles of SIRT1 and other related epigenetic mechanisms in diabetic complications. Thus, this review aims to present a summary of the rapidly growing field of epigenetic regulatory mechanisms, as well as the epigenetic influence of SIRT1 on the development and progression of diabetic complications, including cardiomyopathy, nephropathy, and retinopathy.
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Affiliation(s)
- Jie Wang(a)
- School of Nursing, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Shudong Wang
- Department of Cardiology at the First Hospital of Jilin University, Changchun, China
| | - Jie Wang(b)
- School of Nursing, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Mengjie Xiao
- School of Nursing, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yuanfang Guo
- School of Nursing, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yufeng Tang
- Department of Orthopedic Surgery, The First Affiliated Hospital of Shandong First Medical University, Jinan, China
| | - Jingjing Zhang
- Department of Cardiology at the First Hospital of China Medical University, and Department of Cardiology at the People’s Hospital of Liaoning Province, Shenyang, China
| | - Junlian Gu
- School of Nursing, Cheeloo College of Medicine, Shandong University, Jinan, China
- *Correspondence: Junlian Gu,
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34
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Mohammad G, Duraisamy AJ, Kowluru A, Kowluru RA. Functional Regulation of an Oxidative Stress Mediator, Rac1, in Diabetic Retinopathy. Mol Neurobiol 2019; 56:8643-8655. [PMID: 31300985 PMCID: PMC6842106 DOI: 10.1007/s12035-019-01696-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 07/03/2019] [Indexed: 12/31/2022]
Abstract
PURPOSE Early activation of cytosolic NADPH oxidase-2 (Nox2) in diabetes increases retinal ROS production, damaging their mitochondria. The assembly of Nox2 holoenzyme requires activation of a small molecular weight G protein Rac1. Rac1 activation is regulated by guanine exchange factors and guanine nucleotide-dissociation inhibitors, and post-translational modifications assist in its association with exchange factors and dissociation inhibitors. The goal of this study is to investigate the mechanisms of Rac1 activation in the development of diabetic retinopathy. METHODS The levels of the dissociation inhibitor, prenylating enzyme (farnesyltransferase, FNTA), and exchange factor Vav2 were quantified in human retinal endothelial cells, incubated in normal or high glucose for 96 h. The roles of prenylation and Vav2 in Rac1-Nox2-ROS mitochondrial damage were confirmed in FNTA-siRNA-transfected cells and using the Vav2 inhibitor EHop, respectively. Retinal histopathology and functional changes associated with diabetic retinopathy were analyzed in diabetic mice receiving EHop for 6 months. Key parameters of Rac1 activation were confirmed in the retinal microvasculature from human donors with diabetic retinopathy. RESULTS In HRECs, glucose increased FNTA and Vav2 and decreased the dissociation inhibitor. FNTA-siRNA and EHop inhibited glucose-induced activation of Rac1-Nox2-ROS signaling. In diabetic mice, EHop ameliorated the development of retinopathy and functional/structural abnormalities and attenuated Rac1-Nox2-mitochondrial damage. Similar alterations in Rac1 regulators were observed in retinal microvasculature from human donors with diabetic retinopathy. In diabetes, Rac1 prenylation and its interactions with Vav2 contribute to Nox2-ROS-mitochondrial damage, and the pharmacological inhibitors to attenuate Rac1 interactions with its regulators could have the potential to halt/inhibit the development of diabetic retinopathy. Graphical Abstract Activation of prenylating enzyme farnesyltransferase (FNTA) in diabetes, prenylates Rac1. The binding of Rac1 with guanine nucleotide-dissociation inhibitor (GDI) is decreased, but its association with the guanine exchange factor, Vav2, is increased, resulting in Rac1 activation. Active Rac1 helps in the assembly of Nox2 holoenzyme, and Nox2 activation increases cytosolic ROS production, damaging the mitochondria. Damaged mitochondria accelerate capillary cell apoptosis, and ultimately, results in the development of diabetic retinopathy.
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Affiliation(s)
- Ghulam Mohammad
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University, 4717 St. Antoine, Detroit, MI, 48201, USA
| | - Arul J Duraisamy
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University, 4717 St. Antoine, Detroit, MI, 48201, USA
| | - Anjan Kowluru
- Pharmaceutical Sciences, Wayne State University, Detroit, MI, USA
- John D. Dingell VA Medical Center, Detroit, MI, USA
| | - Renu A Kowluru
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University, 4717 St. Antoine, Detroit, MI, 48201, USA.
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35
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Rossino MG, Dal Monte M, Casini G. Relationships Between Neurodegeneration and Vascular Damage in Diabetic Retinopathy. Front Neurosci 2019; 13:1172. [PMID: 31787868 PMCID: PMC6856056 DOI: 10.3389/fnins.2019.01172] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/16/2019] [Indexed: 12/15/2022] Open
Abstract
Diabetic retinopathy (DR) is a common complication of diabetes and constitutes a major cause of vision impairment and blindness in the world. DR has long been described exclusively as a microvascular disease of the eye. However, in recent years, a growing interest has been focused on the contribution of neuroretinal degeneration to the pathogenesis of the disease, and there are observations suggesting that neuronal death in the early phases of DR may favor the development of microvascular abnormalities, followed by the full manifestation of the disease. However, the mediators that are involved in the crosslink between neurodegeneration and vascular changes have not yet been identified. According to our hypothesis, vascular endothelial growth factor (VEGF) could probably be the most important connecting link between the death of retinal neurons and the occurrence of microvascular lesions. Indeed, VEGF is known to play important neuroprotective actions; therefore, in the early phases of DR, it may be released in response to neuronal suffering, and it would act as a double-edged weapon inducing both neuroprotective and vasoactive effects. If this hypothesis is correct, then any retinal stress causing neuronal damage should be accompanied by VEGF upregulation and by vascular changes. Similarly, any compound with neuroprotective properties should also induce VEGF downregulation and amelioration of the vascular lesions. In this review, we searched for a correlation between neurodegeneration and vasculopathy in animal models of retinal diseases, examining the effects of different neuroprotective substances, ranging from nutraceuticals to antioxidants to neuropeptides and others and showing that reducing neuronal suffering also prevents overexpression of VEGF and vascular complications. Taken together, the reviewed evidence highlights the crucial role played by mediators such as VEGF in the relationship between retinal neuronal damage and vascular alterations and suggests that the use of neuroprotective substances could be an efficient strategy to prevent the onset or to retard the development of DR.
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Affiliation(s)
| | - Massimo Dal Monte
- Department of Biology, University of Pisa, Pisa, Italy.,Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy
| | - Giovanni Casini
- Department of Biology, University of Pisa, Pisa, Italy.,Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy
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36
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Duraisamy AJ, Radhakrishnan R, Seyoum B, Abrams GW, Kowluru RA. Epigenetic Modifications in Peripheral Blood as Potential Noninvasive Biomarker of Diabetic Retinopathy. Transl Vis Sci Technol 2019; 8:43. [PMID: 31871829 PMCID: PMC6924565 DOI: 10.1167/tvst.8.6.43] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 09/12/2019] [Indexed: 02/06/2023] Open
Abstract
PURPOSE Progression of diabetic retinopathy is related to the duration and severity of hyperglycemia, and after 25 years of diabetes, 90% of patients show some signs of retinopathy. Despite initiation of many retinal molecular/biochemical abnormalities, including mitochondrial damage and epigenetic modifications, the disease remains asympotomatic in the initial stages. Our goal is to examine the utility of DNA methylation as a possible biomarker of diabetic retinopathy. METHODS Genomic DNA (gDNA) was isolated from the buffy coat, isolated from blood of diabetic patients with proliferative (PDR) or no retinopathy (No-DR), and nondiabetic subjects (CONT). Methylation of mitochondrial DNA (mtDNA), especially its D-Loop (the site of mtDNA transcription/replication), was quantified by methylated DNA immunoprecipitation and methyl-specific PCR techniques. Results were confirmed in purified mtDNA. The specific D-Loop region with the highest DNA methylation was identified using five overlapping primers, and DNMT1 binding was quantified by chromatin immunoprecipitation. Promoter DNA methylation of DNA mismatch repair (MLH1) and superoxide scavenging (SOD2) enzymes were also quantified. RESULTS Compared to CONT, D-Loop methylation was higher in PDR and No-DR groups, and the D-Loop region responsible for encoding the majority of the mtDNA-encoded genes had significantly higher methylation in the PDR group versus No-DR. Similarly, compared to No-DR, the PDR group also had hypermethylated MHL1 and SOD2 promoters. CONCLUSIONS Blood from PDR patients have higher DNA methylation, than seen in diabetic patients without retinopathy. Thus, DNA methylation can be used as a possible biomarker of diabetic retinopathy. TRANSLATIONAL RELEVANCE DNA methylation status in the blood of diabetic patients could serve as a potential noninvasive biomarker of retinopathy, and also an important readout parameter for testing longitudinal outcome of novel therapeutics for this blinding disease.
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Affiliation(s)
- Arul J. Duraisamy
- Wayne State University, Department of Ophthalmology, Visual and Anatomical Sciences, Detroit, MI, USA
- PerkinElmer Health Sciences Pvt Ltd., Tharamani, India
| | - Rakesh Radhakrishnan
- Wayne State University, Department of Ophthalmology, Visual and Anatomical Sciences, Detroit, MI, USA
| | | | - Gary W. Abrams
- Wayne State University, Department of Ophthalmology, Visual and Anatomical Sciences, Detroit, MI, USA
| | - Renu A. Kowluru
- Wayne State University, Department of Ophthalmology, Visual and Anatomical Sciences, Detroit, MI, USA
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37
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Patel TH, Norman L, Chang S, Abedi S, Liu C, Chwa M, Atilano SR, Thaker K, Lu S, Jazwinski SM, Miceli MV, Udar N, Bota D, Kenney MC. European mtDNA Variants Are Associated With Differential Responses to Cisplatin, an Anticancer Drug: Implications for Drug Resistance and Side Effects. Front Oncol 2019; 9:640. [PMID: 31380278 PMCID: PMC6659439 DOI: 10.3389/fonc.2019.00640] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 07/01/2019] [Indexed: 01/02/2023] Open
Abstract
Background: Cisplatin, a powerful antitumor agent, causes formation of DNA adducts, and activation of apoptotic pathways. Presently, cisplatin resistance develops in up to 70% of patients but the underlying molecular mechanism(s) are unclear and there are no markers to determine which patients will become resistant. Mitochondria play a significant role not only in energy metabolism but also retrograde signaling (mitochondria to nucleus) that modulates inflammation, complement, and apoptosis pathways. Maternally inherited mitochondrial (mt) DNA can be classified into haplogroups representing different ethnic populations that have diverse susceptibilities to diseases and medications. Methods: Transmitochondrial cybrids, where all cell lines possess identical nuclear genomes but either the H (Southern European) or J (Northern European) mtDNA haplogroups, were treated with cisplatin and analyzed for differential responses related to viability, oxidative stress, and expression levels of genes associated with cancer, cisplatin-induced nephrotoxicity and resistance, apoptosis and signaling pathways. Results: The cisplatin-treated-J cybrids showed greater loss of cell viability along with lower levels of reactive oxygen species and mitochondrial membrane potential compared to cisplatin-treated-H cybrids. After cisplatin treatment, J cybrids showed increased gene expression of BAX, CASP3, and CYP51A, but lower levels of SFRP1 compared to untreated-J cybrids. The cisplatin-treated-H cybrids had elevated expression of CDKN1A/P21, which has a role in cisplatin toxicity, compared to untreated-H cybrids. The cisplatin-treated H had higher transcription levels of ABCC1, DHRS2/HEP27, and EFEMP1 compared to cisplatin-treated-J cybrids. Conclusions: Cybrid cell lines that contain identical nuclei but either H mtDNA mitochondria or J mtDNA mitochondria respond differently to cisplatin treatments suggesting involvement of the retrograde signaling (from mitochondria to nucleus) in the drug-induced cell death. Varying toxicities and transcription levels of the H vs. J cybrids after cisplatin treatment support the hypothesis that mtDNA variants play a role in the expression of genes affecting resistance and side effects of cisplatin.
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Affiliation(s)
- Tej H Patel
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Lucas Norman
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Steven Chang
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Sina Abedi
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Catherine Liu
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States.,Illinois Eye and Ear Infirmary, University of Illinois at Chicago, Chicago, IL, United States
| | - Marilyn Chwa
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Shari R Atilano
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Kunal Thaker
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Stephanie Lu
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States.,VA Medical Center Long Beach Hospital, Long Beach, CA, United States
| | - S Michal Jazwinski
- Tulane Center for Aging and Department of Medicine, Tulane University, New Orleans, LA, United States
| | - Michael V Miceli
- Tulane Center for Aging and Department of Medicine, Tulane University, New Orleans, LA, United States
| | - Nitin Udar
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States
| | - Daniela Bota
- Department of Neurology, Neuro-Oncology Division, University of California, Irvine, Irvine, CA, United States
| | - M Cristina Kenney
- Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA, United States.,Department of Pathology and Laboratory Medicine, University of California, Irvine, Irvine, CA, United States
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Duraisamy AJ, Mohammad G, Kowluru RA. Mitochondrial fusion and maintenance of mitochondrial homeostasis in diabetic retinopathy. Biochim Biophys Acta Mol Basis Dis 2019; 1865:1617-1626. [PMID: 30922813 DOI: 10.1016/j.bbadis.2019.03.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/11/2019] [Accepted: 03/22/2019] [Indexed: 01/01/2023]
Abstract
Mitochondria are dynamic in structure, and undergo continuous fusion-fission to maintain their homeostasis. In diabetes, retinal mitochondria are swollen, their membrane is damaged and mitochondrial fusion protein, mitofusin 2 (Mfn2), is decreased. DNA methylation machinery is also activated and methylation status of genes implicated in mitochondrial damage and biogenesis is altered. This study aims to investigate the role of mitochondrial fusion in the development of diabetic retinopathy, and to illustrate the molecular mechanism responsible for Mfn2 suppression. Using human retinal endothelial cells, manipulated for Mfn2, we investigated the role of fusion in mitochondrial structural and functional damage in diabetes. The molecular mechanism of its suppression in diabetic milieu was determined by investigating Mfn2 promoter DNA methylation, and confirmed using molecular and pharmacological inhibitors of DNA methylation. Similar studies were performed in the retinal microvasculature (prepared by hypotonic shock method) of diabetic rats, and human donors with documented diabetic retinopathy. Overexpression of Mfn2 prevented glucose-induced increase in mitochondrial fragmentation, decrease in complex III activity and increase in membrane permeability, mtDNA damage and apoptosis. High glucose hypermethylated Mfn2 promoter and decreased transcription factor (SP1) binding, and Dnmt inhibition protected Mfn2 promoter from these changes. In streptozotocin-induced diabetic rats, intravitreal administration of Dnmt1-siRNA attenuated Mfn2 promoter hypermethylation and restored its expression. Human donors with diabetic retinopathy confirmed Mfn2 promoter DNA hypermethylation. Thus, regulating Mfn2 and its epigenetic modifications by molecular/pharmacological means will protect mitochondrial homeostasis in diabetes, and could attenuate the development of retinopathy in diabetic patients.
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MESH Headings
- Adult
- Aged
- Animals
- Cell Line
- DNA (Cytosine-5-)-Methyltransferase 1/antagonists & inhibitors
- DNA (Cytosine-5-)-Methyltransferase 1/genetics
- DNA (Cytosine-5-)-Methyltransferase 1/metabolism
- DNA Methylation
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Diabetic Retinopathy/genetics
- Diabetic Retinopathy/metabolism
- Diabetic Retinopathy/pathology
- Endothelial Cells/metabolism
- Endothelial Cells/pathology
- Epigenesis, Genetic
- GTP Phosphohydrolases/genetics
- GTP Phosphohydrolases/metabolism
- Homeostasis/genetics
- Humans
- Male
- Middle Aged
- Mitochondria/genetics
- Mitochondria/metabolism
- Mitochondria/pathology
- Mitochondrial Dynamics
- Mitochondrial Proteins/genetics
- Mitochondrial Proteins/metabolism
- Promoter Regions, Genetic
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Rats
- Rats, Wistar
- Retina/metabolism
- Retina/pathology
- Signal Transduction
- Sp1 Transcription Factor/genetics
- Sp1 Transcription Factor/metabolism
- Streptozocin/administration & dosage
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Affiliation(s)
- Arul J Duraisamy
- Kresge Eye Institute, Department of Ophthalmology, Visual & Anatomical Sciences, Wayne State University, Detroit, MI, United States of America
| | - Ghulam Mohammad
- Kresge Eye Institute, Department of Ophthalmology, Visual & Anatomical Sciences, Wayne State University, Detroit, MI, United States of America
| | - Renu A Kowluru
- Kresge Eye Institute, Department of Ophthalmology, Visual & Anatomical Sciences, Wayne State University, Detroit, MI, United States of America.
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Kowluru RA. Mitochondrial Stability in Diabetic Retinopathy: Lessons Learned From Epigenetics. Diabetes 2019; 68:241-247. [PMID: 30665952 PMCID: PMC6341304 DOI: 10.2337/dbi18-0016] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/06/2018] [Indexed: 12/21/2022]
Abstract
Diabetic retinopathy remains the leading cause of acquired blindness in working-age adults. While the cutting-edge research in the field has identified many molecular, functional, and structural abnormalities, the exact molecular mechanism of this devastating disease remains obscure. Diabetic environment drives dysfunction of the power generator of the cell and disturbs the homeostasis of mitochondrial dynamic. Mitochondrial DNA (mtDNA) is damaged, the transcription of mtDNA-encoded genes is impaired, and the electron transport chain is compromised, fueling into a vicious cycle of free radicals. The hyperglycemic milieu also alters the epigenetic machinery, and mtDNA and other genes associated with mitochondrial homeostasis are epigenetically modified, further contributing to the mitochondrial damage. Thus, mitochondria appear to have a significant role in the development of diabetic retinopathy, and unraveling the mechanism responsible for their damage as well as the role of epigenetic modifications in mitochondrial homeostasis should identify novel therapeutic targets. This will have a major impact on inhibiting/halting diabetic retinopathy and preventing the loss of vision.
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Affiliation(s)
- Renu A Kowluru
- Kresge Eye Institute, Wayne State University, Detroit, MI
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40
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Xie MY, Yang Y, Liu P, Luo Y, Tang SB. 5-aza-2'-deoxycytidine in the regulation of antioxidant enzymes in retinal endothelial cells and rat diabetic retina. Int J Ophthalmol 2019; 12:1-7. [PMID: 30662833 DOI: 10.18240/ijo.2019.01.01] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Indexed: 02/08/2023] Open
Abstract
AIM To investigate the roles of a DNA methyltransferase (DNMT) inhibitor 5-aza-2'-deoxycytidine (5-aza-dC) in the regulation of antioxidant enzymes in diabetic retinopathy (DR) models. METHODS DNMTs expressions and activity, and changes of two key antioxidant enzymes in DR, MnSOD (encoded by SOD2 gene) and glutathione S-transferase theta 1 (GSTT1), were quantified in the isolated human retinal endothelial cells (HRECs) exposed to high glucose (HG) with or without 5-aza-dC treatment. The downstream exacerbating factors including vascular endothelial growth factor (VEGF), intercellular adhesion molecule 1 (ICAM-1) and matrix metalloproteinase 2 (MMP2), which are implicated in the pathogenesis of DR and closely related to oxidative stress were also analyzed. The key parameters were confirmed in the retina from streptozotocin (STZ) diabetic rats. RESULTS DNMTs expression and DNMT activity was induced in HRECs exposed to HG. Hyperglycemia decreased MnSOD and GSTT1 expression. 5-aza-dC administration effectively suppressed DNMTs expression and activity and reversed the MnSOD and GSTT1 expression under HG condition. VEGF, ICAM-1 and MMP2 induced by HG were also suppressed by 5-aza-dC treatment. Similar results were observed in the retina from STZ diabetic rats. CONCLUSION Our findings suggest that DNA methylation may serves as one of the mechanisms of antioxidant defense system disruption in DR progression. Modulation of DNA methylation using pharmaceutic means such as DNMT inhibitors could help maintain redox homeostasis and prevent further progression of DR.
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Affiliation(s)
- Man-Yun Xie
- Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha 410011, Hunan Province, China.,Hunan Clinical Research Center of Ophthalmic Disease, Changsha 410011, Hunan Province, China
| | - Yan Yang
- Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha 410011, Hunan Province, China.,Hunan Clinical Research Center of Ophthalmic Disease, Changsha 410011, Hunan Province, China
| | - Ping Liu
- Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha 410011, Hunan Province, China.,Hunan Clinical Research Center of Ophthalmic Disease, Changsha 410011, Hunan Province, China
| | - Yan Luo
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
| | - Shi-Bo Tang
- Aier School of Ophthalmology, Central South University, Changsha 410015, Hunan Province, China.,Aier Research Institute of Ophthalmology, Changsha 410015, Hunan Province, China
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41
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Stoccoro A, Mosca L, Carnicelli V, Cavallari U, Lunetta C, Marocchi A, Migliore L, Coppedè F. Mitochondrial DNA copy number and D-loop region methylation in carriers of amyotrophic lateral sclerosis gene mutations. Epigenomics 2018; 10:1431-1443. [PMID: 30088417 DOI: 10.2217/epi-2018-0072] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIM To investigate mitochondrial DNA (mtDNA) copy number and D-loop region methylation in carriers of SOD1, TARDBP, FUS and C9orf72 mutations. METHODS Investigations were performed in blood DNA from 114 individuals, including amyotrophic lateral sclerosis (ALS) patients, presymptomatic carriers and noncarrier family members. RESULTS Increased mtDNA copy number (p = 0.0001) was observed in ALS patients, and particularly in those with SOD1 or C9orf72 mutations. SOD1 mutation carriers showed also a significant decrease in D-loop methylation levels (p = 0.003). An inverse correlation between D-loop methylation levels and the mtDNA copy number (p = 0.0005) was observed. CONCLUSION Demethylation of the D-loop region could represent a compensatory mechanism for mtDNA upregulation in carriers of ALS-linked SOD1 mutations.
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Affiliation(s)
- Andrea Stoccoro
- Department of Translational Research & New Technologies in Medicine & Surgery, Medical Genetics Laboratory, University of Pisa, Pisa, Italy.,Doctoral School in Genetics Oncology & Clinical Medicine, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Lorena Mosca
- Medical Genetics Unit, Department of Laboratory Medicine, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Vittoria Carnicelli
- Department of Surgical, Medical & Molecular Pathology & Critical Care Medicine, University of Pisa, Pisa, Italy
| | - Ugo Cavallari
- Medical Genetics Unit, Department of Laboratory Medicine, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Christian Lunetta
- NEuroMuscular Omnicentre (NEMO), ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Alessandro Marocchi
- Medical Genetics Unit, Department of Laboratory Medicine, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Lucia Migliore
- Department of Translational Research & New Technologies in Medicine & Surgery, Medical Genetics Laboratory, University of Pisa, Pisa, Italy
| | - Fabio Coppedè
- Department of Translational Research & New Technologies in Medicine & Surgery, Medical Genetics Laboratory, University of Pisa, Pisa, Italy
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