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Luo R, Li L, Han Q, Fu J, Xiao F. HAGLR, stabilized by m6A modification, triggers PTEN-Akt signaling cascade-mediated RPE cell pyroptosis via sponging miR-106b-5p. J Biochem Mol Toxicol 2024; 38:e23596. [PMID: 38088496 DOI: 10.1002/jbt.23596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/12/2023] [Accepted: 11/20/2023] [Indexed: 01/18/2024]
Abstract
Consistent hyperglycaemia on retinal microvascular tissues is recognized as a vital inducer of diabetic retinopathy (DR) pathogenesis. In view of the essential functionality of long noncoding RNAs (lncRNAs) in multiple human diseases, we aim to figure out the exact role and underlying mechanisms of lncRNA HOXD Cluster Antisense RNA 1 (HAGLR) in DR pathogenesis. Serum specimens from patients with proliferative DR and healthy volunteers were collected for measuring HAGLR levels. Human primary retinal pigment epithelium (HRPE) cells kept in high glucose (HG) condition were applied to simulating hyperglycaemia of DR pathology in vitro. Cell proliferation, apoptosis, either pyroptosis was assess using Cell Counting Kit-8 TUNEL, flow cytometry, and enzyme-linked immunoassay assays. Bioinformatics analysis was subjected to examine the interaction between HAGLR and N6-methyladenosine (m6A)-bind protein IGF2BP2, as determined using RNA immunoprecipitation and RNA pull-down. Luciferase reporter assay was performed to assess the HAGLR-miR-106b-5p-PTEN axis. Levels of pyroptosis-associated biomarkers were detected using western blotting. Aberrantly overexpressed HAGLR was uncovered in the serum samples of DR patients and HG-induced HRPE cells, of which knockdown attenuated HG-induced cytotoxic impacts on cell apoptosis and pyroptosis. Whereas, reinforced HAGLR further aggravated these effects. IGF2BP2 positively regulated HAGLR in a m6A-dependent manner. HAGLR served as a sponge for miR-106b-5p to upregulate PTEN, thereby activating Akt signaling cascade. Rescue assays demonstrated that PTEN overexpression abolished the inhibition of silenced HAGLR on pyroptosis in HRPE cells. HAGLR, epigenetically modified by IGF2BP2 in an m6A-dependent manner, functioned as a sponge for miR-106b-5p, thereby activating PTEN/Akt signaling cascade to accelerate DR pathology.
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Affiliation(s)
- Rong Luo
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang Medical College, Jiangxi Provincial People's Hospital, Nanchang, Jiangxi, China
| | - Lan Li
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang Medical College, Jiangxi Provincial People's Hospital, Nanchang, Jiangxi, China
| | - Qingluan Han
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang Medical College, Jiangxi Provincial People's Hospital, Nanchang, Jiangxi, China
| | - Jingsong Fu
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang Medical College, Jiangxi Provincial People's Hospital, Nanchang, Jiangxi, China
| | - Fan Xiao
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang Medical College, Jiangxi Provincial People's Hospital, Nanchang, Jiangxi, China
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Ebrahimi M, Thompson P, Lauer AK, Sivaprasad S, Perry G. The retina-brain axis and diabetic retinopathy. Eur J Ophthalmol 2023; 33:2079-2095. [PMID: 37259525 DOI: 10.1177/11206721231172229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Diabetic retinopathy (DR) is a major contributor to permanent vision loss and blindness. Changes in retinal neurons, glia, and microvasculature have been the focus of intensive study in the quest to better understand DR. However, the impact of diabetes on the rest of the visual system has received less attention. There are reports of associations of changes in the visual system with preclinical and clinical manifestations of diabetes. Simultaneous investigation of the retina and the brain may shed light on the mechanisms underlying neurodegeneration in diabetics. Additionally, investigating the links between DR and other neurodegenerative disorders of the brain including Alzheimer's and Parkinson's disease may reveal shared mechanisms for neurodegeneration and potential therapy options.
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Affiliation(s)
- Moein Ebrahimi
- School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Network of Immunity in Infection, Malignancy, and Autoimmunity, Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Paul Thompson
- Imaging Genetics Center, Mark and Mary Stevens Institute for Neuroimaging and Informatics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Andreas K Lauer
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Sobha Sivaprasad
- National Institute of Health and Care Research Moorfields Biomedical Research Centre, Moorfields Eye Hospital, London, UK
| | - George Perry
- Department of Neuroscience, Developmental and Regenerative Biology, University of Texas and San Antonio, San Antonio, TX, USA
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3
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Lai QL, Xie T, Zheng WD, Huang Y. Effect of miR-27b-3p and Nrf2 in human retinal pigment epithelial cell induced by high-glucose. Int J Ophthalmol 2023; 16:1582-1588. [PMID: 37854382 PMCID: PMC10559042 DOI: 10.18240/ijo.2023.10.04] [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: 01/20/2023] [Accepted: 08/02/2023] [Indexed: 10/20/2023] Open
Abstract
AIM To determine whether the microRNA-27b-3p (miR-27b-3p)/NF-E2-related factor 2 (Nrf2) pathway plays a role in human retinal pigment epithelial (hRPE) cell response to high glucose, how miR-27b-3p and Nrf2 expression are regulated, and whether this pathway could be specifically targeted. METHODS hRPE cells were cultured in normal glucose or high glucose for 1, 3, or 6d before measuring cellular proliferation rates using cell counting kit-8 and reactive oxygen species (ROS) levels using a dihydroethidium kit. miR-27b-3p, Nrf2, NAD(P)H quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1) mRNA and protein levels were analyzed using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and immunocytofluorescence (ICF), respectively. Western blot analyses were performed to determine nuclear and total Nrf2 protein levels. Nrf2, NQO1, and HO-1 expression levels by RT-qPCR, ICF, or Western blot were further tested after miR-27b-3p overexpression or inhibitor lentiviral transfection. Finally, the expression level of those target genes was analyzed after treating hRPE cells with pyridoxamine. RESULTS Persistent exposure to high glucose gradually suppressed hRPE Nrf2, NQO1, and HO-1 mRNA and protein levels and increased miR-27b-3p mRNA levels. High glucose also promoted ROS release and inhibited cellular proliferation. Nrf2, NQO1, and HO-1 mRNA levels decreased after miR-27b-3p overexpression and, conversely, both mRNA and protein levels increased after expressing a miR-27b-3p inhibitor. After treating hRPE cells exposed to high glucose with pyridoxamine, ROS levels tended to decreased, proliferation rate increased, Nrf2, NQO1, and HO-1 mRNA and protein levels were upregulated, and miR-27b-3p mRNA levels were suppressed. CONCLUSION Nrf2 is a downstream target of miR-27b-3p. Furthermore, the miR-27b-3p inhibitor pyridoxamine can alleviate high glucose injury by regulating the miR-27b-3p/Nrf2 axis.
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Affiliation(s)
- Qiao-Ling Lai
- Department of Ophthalmology and Optometry, Fujian Medical University, Fuzhou 350004, Fujian Province, China
| | - Ting Xie
- The First Affiliated Hospital of Fujian Medical University, Fuzhou 350004, Fujian Province, China
| | - Wei-Dong Zheng
- The First Affiliated Hospital of Fujian Medical University, Fuzhou 350004, Fujian Province, China
| | - Yan Huang
- Department of Ophthalmology and Optometry, Fujian Medical University, Fuzhou 350004, Fujian Province, China
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Towards a New Biomarker for Diabetic Retinopathy: Exploring RBP3 Structure and Retinoids Binding for Functional Imaging of Eyes In Vivo. Int J Mol Sci 2023; 24:ijms24054408. [PMID: 36901838 PMCID: PMC10002987 DOI: 10.3390/ijms24054408] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/10/2023] [Accepted: 02/21/2023] [Indexed: 02/25/2023] Open
Abstract
Diabetic retinopathy (DR) is a severe disease with a growing number of afflicted patients, which places a heavy burden on society, both socially and financially. While there are treatments available, they are not always effective and are usually administered when the disease is already at a developed stage with visible clinical manifestation. However, homeostasis at a molecular level is disrupted before visible signs of the disease are evident. Thus, there has been a constant search for effective biomarkers that could signal the onset of DR. There is evidence that early detection and prompt disease control are effective in preventing or slowing DR progression. Here, we review some of the molecular changes that occur before clinical manifestations are observable. As a possible new biomarker, we focus on retinol binding protein 3 (RBP3). We argue that it displays unique features that make it a very good biomarker for non-invasive, early-stage DR detection. Linking chemistry to biological function and focusing on new developments in eye imaging and two-photon technology, we describe a new potential diagnostic tool that would allow rapid and effective quantification of RBP3 in the retina. Moreover, this tool would also be useful in the future to monitor therapeutic effectiveness if levels of RBP3 are elevated by DR treatments.
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Iker Etchegaray J, Kelley S, Penberthy K, Karvelyte L, Nagasaka Y, Gasperino S, Paul S, Seshadri V, Raymond M, Marco AR, Pinney J, Stremska M, Barron B, Lucas C, Wase N, Fan Y, Unanue E, Kundu B, Burstyn-Cohen T, Perry J, Ambati J, Ravichandran KS. Phagocytosis in the retina promotes local insulin production in the eye. Nat Metab 2023; 5:207-218. [PMID: 36732622 PMCID: PMC10457724 DOI: 10.1038/s42255-022-00728-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 12/16/2022] [Indexed: 02/04/2023]
Abstract
The retina is highly metabolically active, relying on glucose uptake and aerobic glycolysis. Situated in close contact to photoreceptors, a key function of cells in the retinal pigment epithelium (RPE) is phagocytosis of damaged photoreceptor outer segments (POS). Here we identify RPE as a local source of insulin in the eye that is stimulated by POS phagocytosis. We show that Ins2 messenger RNA and insulin protein are produced by RPE cells and that this production correlates with RPE phagocytosis of POS. Genetic deletion of phagocytic receptors ('loss of function') reduces Ins2, whereas increasing the levels of the phagocytic receptor MerTK ('gain of function') increases Ins2 production in male mice. Contrary to pancreas-derived systemic insulin, RPE-derived local insulin is stimulated during starvation, which also increases RPE phagocytosis. Global or RPE-specific Ins2 gene deletion decreases retinal glucose uptake in starved male mice, dysregulates retinal physiology, causes defects in phototransduction and exacerbates photoreceptor loss in a mouse model of retinitis pigmentosa. Collectively, these data identify RPE cells as a phagocytosis-induced local source of insulin in the retina, with the potential to influence retinal physiology and disease.
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Affiliation(s)
- J Iker Etchegaray
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Shannon Kelley
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Kristen Penberthy
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Laura Karvelyte
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Yosuke Nagasaka
- Center for Advanced Vision Science, University of Virginia, Charlottesville, VA, USA
| | - Sofia Gasperino
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Soumen Paul
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, USA
| | - Vikram Seshadri
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, USA
| | - Michael Raymond
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Ana Royo Marco
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Jonathan Pinney
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Marta Stremska
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Brady Barron
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Christopher Lucas
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- University of Edinburgh, Edinburgh, UK
| | - Nishikant Wase
- Biomolecular Analysis Facility, University of Virginia, Charlottesville, VA, USA
| | - Yong Fan
- Drexel University, Philadelphia, PA, USA
| | - Emil Unanue
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Bijoy Kundu
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, USA
| | - Tal Burstyn-Cohen
- Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Justin Perry
- Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jayakrishna Ambati
- Center for Advanced Vision Science, University of Virginia, Charlottesville, VA, USA
- Ophthalmology, University of Virginia, Charlottesville, VA, USA
| | - Kodi S Ravichandran
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA.
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA.
- Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem, Israel.
- VIB/UGent Inflammation Research Centre, and Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
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Amato R, Catalani E, Dal Monte M, Cammalleri M, Cervia D, Casini G. Morpho-functional analysis of the early changes induced in retinal ganglion cells by the onset of diabetic retinopathy: The effects of a neuroprotective strategy. Pharmacol Res 2022; 185:106516. [DOI: 10.1016/j.phrs.2022.106516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/05/2022] [Accepted: 10/14/2022] [Indexed: 10/31/2022]
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7
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Liu H, Stepicheva NA, Ghosh S, Shang P, Chowdhury O, Daley RA, Yazdankhah M, Gupta U, Hose SL, Valapala M, Fitting CS, Strizhakova A, Shan Y, Feenstra D, Sahel JA, Jayagopal A, Handa JT, Zigler JS, Fort PE, Sodhi A, Sinha D. Reducing Akt2 in retinal pigment epithelial cells causes a compensatory increase in Akt1 and attenuates diabetic retinopathy. Nat Commun 2022; 13:6045. [PMID: 36229454 PMCID: PMC9561713 DOI: 10.1038/s41467-022-33773-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 10/03/2022] [Indexed: 01/14/2023] Open
Abstract
The retinal pigment epithelium (RPE) plays an important role in the development of diabetic retinopathy (DR), a leading cause of blindness worldwide. Here we set out to explore the role of Akt2 signaling-integral to both RPE homeostasis and glucose metabolism-to DR. Using human tissue and genetically manipulated mice (including RPE-specific conditional knockout (cKO) and knock-in (KI) mice), we investigate whether Akts in the RPE influences DR in models of diabetic eye disease. We found that Akt1 and Akt2 activities were reciprocally regulated in the RPE of DR donor tissue and diabetic mice. Akt2 cKO attenuated diabetes-induced retinal abnormalities through a compensatory upregulation of phospho-Akt1 leading to an inhibition of vascular injury, inflammatory cytokine release, and infiltration of immune cells mediated by the GSK3β/NF-κB signaling pathway; overexpression of Akt2 has no effect. We propose that targeting Akt1 activity in the RPE may be a novel therapy for treating DR.
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Affiliation(s)
- Haitao Liu
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Nadezda A. Stepicheva
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Sayan Ghosh
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Peng Shang
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA ,grid.280881.b0000 0001 0097 5623Present Address: Doheny Eye Institute, Pasadena, CA USA
| | - Olivia Chowdhury
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Rachel A. Daley
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Meysam Yazdankhah
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA ,grid.443945.b0000 0004 0566 7998Present Address: Neural Stem Cell Institute, Rensselaer, NY USA
| | - Urvi Gupta
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Stacey L. Hose
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Mallika Valapala
- grid.411377.70000 0001 0790 959XSchool of Optometry, Indiana University, Bloomington, IN USA
| | - Christopher Scott Fitting
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Anastasia Strizhakova
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Yang Shan
- grid.214458.e0000000086837370Kellogg Eye Center, University of Michigan School of Medicine, Ann Arbor, MI USA
| | - Derrick Feenstra
- grid.417570.00000 0004 0374 1269Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Ltd., Basel, Switzerland
| | - José-Alain Sahel
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA ,grid.462844.80000 0001 2308 1657Institut de la Vision, INSERM, CNRS, Sorbonne Université, Paris, France
| | | | - James T. Handa
- grid.21107.350000 0001 2171 9311The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - J. Samuel Zigler
- grid.21107.350000 0001 2171 9311The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Patrice E. Fort
- grid.214458.e0000000086837370Kellogg Eye Center, University of Michigan School of Medicine, Ann Arbor, MI USA
| | - Akrit Sodhi
- grid.21107.350000 0001 2171 9311The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. .,The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Jones MA, Jadeja RN, Flandrin O, Abdelrahman AA, Thounojam MC, Thomas S, Dai C, Xiao H, Chen JK, Smith SB, Bartoli M, Martin PM, Powell FL. Autonomous regulation of retinal insulin biosynthesis in diabetes. Neuropeptides 2022; 94:102258. [PMID: 35660758 PMCID: PMC10440820 DOI: 10.1016/j.npep.2022.102258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 05/08/2022] [Accepted: 05/15/2022] [Indexed: 10/18/2022]
Abstract
Diabetic retinopathy (DR) is a neurodegenerative disease that results as a complication of dysregulated glucose metabolism, or diabetes. The signaling of insulin is lost or dampened in diabetes, but this hormone has also been shown to be an important neurotrophic factor which supports neurons of the brain. The role of local insulin synthesis and secretion in the retina, however, is unclear. We have investigated whether changes in local insulin synthesis occur in the diabetic retina and in response to stressors known to initiate retinal neurodegenerative processes. The expression of insulin and its cleavage product, c-peptide, were examined in retinas of a Type I diabetes animal model and human postmortem donors with DR. We detected mRNAs for insulin I (Ins1), insulin II (Ins2) and human insulin (Ins) by quantitative real-time polymerase chain reaction (qRT-PCR) and in situ hybridization. Using an ex-vivo system, isolated neuroretinas and retinal pigmented epithelium (RPE) layers were exposed to glycemic, oxidative and inflammatory environments to measure insulin gene transcripts produced de novo in the retina under disease-relevant conditions. The expression of insulin in the retina was altered with the progression of diabetes in STZ mice and donors with DR. Transcription factors for insulin, were simultaneously expressed in a pattern matching insulin genes. Furthermore, de novo insulin mRNA in isolated retinas was induced by acute stress. RPE explants displayed the most pronounced changes in Ins1 and Ins2. This data reveals that the retina, like the brain, is an organ capable of producing local insulin and this synthesis is altered in diabetes.
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Affiliation(s)
- Malita A Jones
- Department of Biochemistry and Molecular Biology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Ravirajsinh N Jadeja
- Department of Biochemistry and Molecular Biology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Orneika Flandrin
- UC Berkeley School of Optometry, University of California, Berkeley, CA, USA
| | - Ammar A Abdelrahman
- Department of Pharmacology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA; Department of Clinical Pharmacy, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Menaka C Thounojam
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Shakera Thomas
- Department of Biochemistry and Molecular Biology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Caihong Dai
- Department of Cell Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Haiyan Xiao
- Department of Cell Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Jian-Kang Chen
- Department of Cell Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Sylvia B Smith
- Department of Cell Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Manuela Bartoli
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Pamela M Martin
- Department of Biochemistry and Molecular Biology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA; Department of Cell Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA; Georgia Cancer Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Folami L Powell
- Department of Biochemistry and Molecular Biology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.
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Berkowitz BA, Podolsky RH, Childers KL, Burgoyne T, De Rossi G, Qian H, Roberts R, Katz R, Waseem R, Goodman C. Functional Changes Within the Rod Inner Segment Ellipsoid in Wildtype Mice: An Optical Coherence Tomography and Electron Microscopy Study. Invest Ophthalmol Vis Sci 2022; 63:8. [PMID: 35816042 PMCID: PMC9284466 DOI: 10.1167/iovs.63.8.8] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose To test the hypothesis that changing energy needs alter mitochondria distribution within the rod inner segment ellipsoid. Methods In mice with relatively smaller (C57BL/6J [B6J]) or greater (129S6/ev [S6]) retina mitochondria maximum reserve capacity, the profile shape of the rod inner segment ellipsoid zone (ISez) was measured with optical coherence tomography (OCT) under higher (dark) or lower (light) energy demand conditions. ISez profile shape was characterized using an unbiased ellipse descriptor (minor/major aspect ratio). Other bioenergy indexes evaluated include the external limiting membrane-retinal pigment epithelium (ELM-RPE) thickness and the magnitude of the signal intensity of a hyporeflective band located between the photoreceptor tips and apical RPE. The spatial distribution of rod ellipsoid mitochondria were also examined with electron microscopy. Results In B6J mice, darkness produced a greater ISez aspect ratio, thinner ELM-RPE, and a smaller hyporeflective band intensity than in light. In S6 mice, dark and light ISez aspect ratio values were not different and were greater than in light-adapted B6J mice; dark-adapted S6 mice showed smaller ELM-RPE thinning versus light, and negligible hyporeflective band intensity in the light. In B6J mice, mitochondria number in light increased in the distal inner segment ellipsoid and decreased proximally. In S6 mice, mitochondria number in the inner segment ellipsoid were not different between light and dark, and were greater than in B6J mice. Conclusions These data raise the possibility that rod mitochondria activity in mice can be noninvasively evaluated based on the ISez profile shape, a new OCT index that complements OCT energy biomarkers measured outside of the ISez region.
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Affiliation(s)
- Bruce A Berkowitz
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Robert H Podolsky
- Biostatistics and Study Methodology, Children's National Hospital, Silver Spring, Maryland, United States
| | - Karen Lins Childers
- Beaumont Research Institute, Beaumont Health, Royal Oak, Michigan, Unites States
| | - Tom Burgoyne
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Giulia De Rossi
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, Unites States
| | - Robin Roberts
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Ryan Katz
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Rida Waseem
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Cole Goodman
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
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10
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Huang C, Qi P, Cui H, Lu Q, Gao X. CircFAT1 regulates retinal pigment epithelial cell pyroptosis and autophagy via mediating m6A reader protein YTHDF2 expression in diabetic retinopathy. Exp Eye Res 2022; 222:109152. [PMID: 35714699 DOI: 10.1016/j.exer.2022.109152] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 05/28/2022] [Accepted: 06/10/2022] [Indexed: 11/04/2022]
Abstract
Diabetic retinopathy (DR) is a serious blinding complication of diabetes. At present, the therapeutic intervention effect is limited. We aimed to investigate the circRNA expression profiles in retinal proliferative fibrovascular membranes of patients with DR and explore the effect of circFAT1 on pyroptosis and autophagy of high glucose (HG)-induced retinal pigment epithelial (RPE) cells and its molecualr mechanism. In this study, circRNA sequencing was performed to determine the expression profiles of circRNAs in DR patients. The expression of circFAT1 was measured by qRT-PCR. Cell counting kit-8, transmission electron microscope, western blot, immunofluorescence and enzyme-linked immunosorbent assay were conducted to explore the roles of HG and circFAT1 in RPE cell pyroptosis and autophagy. RNA pull down was used to determine the binding protein of circFAT1. Our data showed that HG significantly reduced the viability of RPE cells, inhibited cell autophagy and contributed to cell pyroptosis. In addition, a total of 189 differentially expressed circRNAs (DEcircRNAs) were identified between DR patients and non-DR patients, including 93 upregulated and 96 downregulated DEcircRNAs in the retinal proliferative fibrovascular membranes of DR patients. Pathway analysis showed that DEcircRNAs were mainly involved in MAPK signaling pathway, TGF-beta signaling pathway and adherens junction. Moreover, circFAT1 was significantly downregulated in retinal proliferative fibrovascular membranes of DR patients and HG-induced RPE cells. CircFAT1 overexpression remarkably enhanced the expression of LC3B, while reduced the expression of GSDMD in HG-induced RPE cells. RNA pull down combined with western blot analysis indicated that circFAT1 bound to m6A reader YTHDF2. YTHDF2 overexpression significantly increased the protein expression of LC3B in HG-induced RPE cells. In summary, circFAT1 promoted autophagy and inhibited pyroptosis of RPE cells induced by HG, and could combine with YTHDF2. This study provides new ideas for DR prevention and treatment.
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Affiliation(s)
- Chengchi Huang
- Department of Ophthalmology, The Fourth Hospital of Harbin Medical University, 37 YiYuan Street, NanGang District, Harbin, 150001, China.
| | - Peng Qi
- Department of Ophthalmology, The Fourth Hospital of Harbin Medical University, 37 YiYuan Street, NanGang District, Harbin, 150001, China
| | - Hao Cui
- Department of Ophthalmology, Harbin 242 Hospital, 3 WeiJian Road, PingFang District, Harbin, China
| | - Qun Lu
- Department of Ophthalmology, Sino-Singapore Eco-city Hospital of TianJin Medical University, Tianjin, 300467, China
| | - Xue Gao
- Department of Ophthalmology, The Fourth Hospital of Harbin Medical University, 37 YiYuan Street, NanGang District, Harbin, 150001, China
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11
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Lelyte I, Ahmed Z, Kaja S, Kalesnykas G. Structure-Function Relationships in the Rodent Streptozotocin-Induced Model for Diabetic Retinopathy: A Systematic Review. J Ocul Pharmacol Ther 2022; 38:271-286. [PMID: 35325558 PMCID: PMC9125572 DOI: 10.1089/jop.2021.0128] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The streptozotocin (STZ)-induced rodent model is one of the most commonly employed models in preclinical drug discovery for diabetic retinopathy (DR). However, standardization and validation of experimental readouts are largely lacking. The aim of this systematic review was to identify and compare the most useful readouts of STZ-induced DR and provide recommendations for future study design based on our findings. We performed a systematic search using 2 major databases, PubMed and EMBASE. Only articles describing STZ-induced DR describing both functional and structural readouts were selected. We also assessed the risk of bias and analyzed qualitative data in the selected studies. We identified 21 studies that met our inclusion/exclusion criteria, using either rats or mice and study periods of 2 to 24 weeks. Glucose level thresholds used to define hyperglycemia were inconsistent between studies, however, most studies used either 250 or 300.6 mg/dL as a defining criterion for hyperglycemia. All included studies performed electroretinography (ERG) and reported a reduction in a-, b-, or c-wave and/or oscillatory potential amplitudes. Spectral-domain optical coherence tomography and fluorescein angiography, as well as immunohistochemical and histopathological analyses showed reductions in retinal thickness, vascular changes, and presence of inflammation. Risk of bias assessment showed that all studies had a high risk of bias due to lack of reporting or correctly following procedures. Our systematic review highlights that ERG represents the most consistent functional readout in the STZ model. However, due to the high risk of bias, caution must be used when interpreting these studies.
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Affiliation(s)
- Inesa Lelyte
- Research and Development Division, Experimentica Ltd., Kuopio, Finland.,Institute of Inflammation and Ageing, and University of Birmingham, Birmingham, United Kingdom
| | - Zubair Ahmed
- Institute of Inflammation and Ageing, and University of Birmingham, Birmingham, United Kingdom.,Center for Trauma Sciences Research, University of Birmingham, Birmingham, United Kingdom
| | - Simon Kaja
- Departments of Ophthalmology and Molecular Pharmacology and Neuroscience, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, USA.,Experimentica Ltd., Research and Development Division, Forest Park, Illinois, USA
| | - Giedrius Kalesnykas
- Research and Development Division, Experimentica Ltd., Kuopio, Finland.,Experimentica Ltd., Research and Development Division, Vilnius, Lithuania
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12
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Ipp E. Diabetic Retinopathy and Insulin Insufficiency: Beta Cell Replacement as a Strategy to Prevent Blindness. Front Endocrinol (Lausanne) 2021; 12:734360. [PMID: 34912295 PMCID: PMC8667804 DOI: 10.3389/fendo.2021.734360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 09/28/2021] [Indexed: 12/02/2022] Open
Abstract
Diabetic retinopathy (DR) is a potentially devastating complication of diabetes because it puts patients at risk of blindness. Diabetes is a common cause of blindness in the U.S. and worldwide and is dramatically increasing in global prevalence. Thus new approaches are needed to prevent this dreaded complication. There is extensive data that indicates beta cell secretory failure is a risk factor for DR, independent of its influence on glycemic control. This perspective article will provide evidence for insufficient endogenous insulin secretion as an important factor in the development of DR. The areas of evidence discussed are: (a) Presence of insulin receptors in the retina, (b) Clinical studies that show an association of beta cell insufficiency with DR, (c) Treatment with insulin in type 2 diabetes, a marker for endogenous insulin deficiency, is an independent risk factor for DR, (d) Recent clinical studies that link DR with an insulin deficient form of type 2 diabetes, and (e) Beta cell replacement studies that demonstrate endogenous insulin prevents progression of DR. The cumulative data drive our conclusion that beta cell replacement will have an important role in preventing DR and/or mitigating its severity in both type 1 diabetes and insulinopenic type 2 diabetes.
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Affiliation(s)
- Eli Ipp
- Department of Medicine, The Lundquist Institute at Harbor-University of California Los Angeles (UCLA) Medical Center, Torrance, CA, United States
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13
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Tonade D, Kern TS. Photoreceptor cells and RPE contribute to the development of diabetic retinopathy. Prog Retin Eye Res 2021; 83:100919. [PMID: 33188897 PMCID: PMC8113320 DOI: 10.1016/j.preteyeres.2020.100919] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 10/27/2020] [Accepted: 10/31/2020] [Indexed: 12/26/2022]
Abstract
Diabetic retinopathy (DR) is a leading cause of blindness. It has long been regarded as vascular disease, but work in the past years has shown abnormalities also in the neural retina. Unfortunately, research on the vascular and neural abnormalities have remained largely separate, instead of being integrated into a comprehensive view of DR that includes both the neural and vascular components. Recent evidence suggests that the most predominant neural cell in the retina (photoreceptors) and the adjacent retinal pigment epithelium (RPE) play an important role in the development of vascular lesions characteristic of DR. This review summarizes evidence that the outer retina is altered in diabetes, and that photoreceptors and RPE contribute to retinal vascular alterations in the early stages of the retinopathy. The possible molecular mechanisms by which cells of the outer retina might contribute to retinal vascular damage in diabetes also are discussed. Diabetes-induced alterations in the outer retina represent a novel therapeutic target to inhibit DR.
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Affiliation(s)
- Deoye Tonade
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
| | - Timothy S Kern
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA; Veterans Administration Medical Center Research Service, Cleveland, OH, USA; Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA; Veterans Administration Medical Center Research Service, Long Beach, CA, USA.
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14
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Li X, Yu Y, Liu X, Shi Y, Jin X, Zhang Y, Xu S, Zhang N, Dong L, Zhou S, Wang Y, Ding Y, Song Z, Zhang H. Quantitative analysis of retinal vessel density and thickness changes in diabetes mellitus evaluated using optical coherence tomography angiography: a cross-sectional study. BMC Ophthalmol 2021; 21:259. [PMID: 34130654 PMCID: PMC8207746 DOI: 10.1186/s12886-021-01988-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 05/10/2021] [Indexed: 12/16/2022] Open
Abstract
Background Diabetic retinopathy is the most common microvascular complication of diabetes; however, early changes in retinal microvessels are difficult to detect clinically, and a patient’s vision may have begun to deteriorate by the time a problem is identified. Optical coherence tomography angiography (OCTA) is an innovative tool for observing capillaries in vivo. The aim of this study was to analyze retinal vessel density and thickness changes in patients with diabetes. Methods This was a retrospective, observational cross-sectional study. Between August 2018 and February 2019, we collected OCTA data from healthy participants and diabetics from the First Affiliated Hospital of Harbin Medical University. Analyzed their retinal vessel density and thickness changes. Results A total of 97 diabetic patients with diabetes at different severity stages of diabetic retinopathy and 85 controls were involved in the experiment. Diabetic patients exhibited significantly lower retinal VD (particularly in the deep vascular complexes), thickening of the neurosensory retina, and thinning of the retinal pigment epithelium compared with controls. In the control group, nondiabetic retinopathy group and mild diabetic retinopathy group, superficial VD was significantly correlated with retinal thickness (r = 0.3886, P < 0.0001; r = 0.3276, P = 0.0019; r = 0.4614, P = 0.0024, respectively). Conclusions Patients with diabetes exhibit ischemia of the retinal capillaries and morphologic changes in vivo prior to vision loss. Therefore, OCTA may be useful as a quantitative method for the early detection of diabetic retinopathy. Supplementary Information The online version contains supplementary material available at 10.1186/s12886-021-01988-2.
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Affiliation(s)
- Xinyue Li
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yu Yu
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Xueting Liu
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yan Shi
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Xin Jin
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yanyan Zhang
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Shuo Xu
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Nan Zhang
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Li Dong
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Sujun Zhou
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yingbin Wang
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yiheng Ding
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Zhen Song
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Hong Zhang
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
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15
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Scimone C, Donato L, Alibrandi S, Vadalà M, Giglia G, Sidoti A, D'Angelo R. N-retinylidene-N-retinylethanolamine adduct induces expression of chronic inflammation cytokines in retinal pigment epithelium cells. Exp Eye Res 2021; 209:108641. [PMID: 34058230 DOI: 10.1016/j.exer.2021.108641] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 05/06/2021] [Accepted: 05/24/2021] [Indexed: 12/14/2022]
Abstract
Blindness due to photoreceptor degeneration is observed in both genetic and acquired eye disorders. Long blue light exposure can contribute to increase levels of oxidative compounds within the retinal pigment epithelium (RPE), enhancing risk of retinal damage. In retina, reactive oxygen species contribute to the activation of inflammatory cascade. If chronic, this inflammatory response can result in photoreceptor death. Therefore, we investigated the effects of the endogenous adduct N-retinylidene-N-retinylethanolamine (A2E) on RPE cells, in order to identify the most dysregulated cytokines and their related inflammatory pathways. RPE cells were exposed to A2E and blue light for 3h and 6h. By transcriptome analysis, we identified differentially expressed genes in A2E-treated cells, when compared to untreated ones. Expression values were quantified by the Limma R package. Enrichment analysis was performed according to the "Reactome" and the Gene Ontology databases. Expression of pro-inflammatory cytokines increased after 3h of A2E treatment and pathways related to IL-6 and IL-1 signaling resulted enriched. Also the up-regulation of genes having a protective role against inflammation was observed. Moreover, our results show that ferroptosis could contribute to RPE degeneration induced by A2E and blue light. Dysregulated genes related to retinal degeneration triggered by oxidative damage and inflammatory response activation identified in this study can be considered as potential biomarkers for targeted therapies.
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Affiliation(s)
- Concetta Scimone
- Department of Biomedical, Dental, Morphological and Functional Imaging Sciences, University of Messina, Via Consolare Valeria 1, 98125, Messina, Italy; Department of Biomolecular Strategies, Genetics and Avant-Garde Therapies, I.E.ME.S.T., Via Michele Miraglia, 90139, Palermo, Italy
| | - Luigi Donato
- Department of Biomedical, Dental, Morphological and Functional Imaging Sciences, University of Messina, Via Consolare Valeria 1, 98125, Messina, Italy; Department of Biomolecular Strategies, Genetics and Avant-Garde Therapies, I.E.ME.S.T., Via Michele Miraglia, 90139, Palermo, Italy.
| | - Simona Alibrandi
- Department of Biomedical, Dental, Morphological and Functional Imaging Sciences, University of Messina, Via Consolare Valeria 1, 98125, Messina, Italy; Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d'Alcontres 31, 98166, Messina, Italy
| | - Maria Vadalà
- Department of Experimental Biomedicine and Clinical Neuroscience, Ophthalmology Section, University of Palermo, 90127, Palermo, Italy
| | - Giuseppe Giglia
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (BiND), Section of Human Physiology, University of Palermo, 90134, Palermo, Italy
| | - Antonina Sidoti
- Department of Biomedical, Dental, Morphological and Functional Imaging Sciences, University of Messina, Via Consolare Valeria 1, 98125, Messina, Italy
| | - Rosalia D'Angelo
- Department of Biomedical, Dental, Morphological and Functional Imaging Sciences, University of Messina, Via Consolare Valeria 1, 98125, Messina, Italy
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16
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Biswas L, Ibrahim KS, Li X, Zhou X, Zeng Z, Craft J, Shu X. Effect of a TSPO ligand on retinal pigment epithelial cholesterol homeostasis in high-fat fed mice, implication for age-related macular degeneration. Exp Eye Res 2021; 208:108625. [PMID: 34022174 DOI: 10.1016/j.exer.2021.108625] [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: 01/11/2021] [Revised: 04/19/2021] [Accepted: 05/11/2021] [Indexed: 02/07/2023]
Abstract
Age-related Macular Degeneration (AMD) is a major cause of sight impairment in the elderly with complex aetiology involving genetics and environment and with limited therapeutic options which have limited efficacy. We have previously shown in a mouse-model of the condition, induced by feeding a high fat diet, that adverse effects of the diet can be reversed by co-administration of the TSPO activator, etifoxine. We extend those observations showing improvements in retinal pigment epithelial (RPE) cells with decreased lipids and enhanced expression of cholesterol metabolism and transport enzymes. Further, etifoxine decreased levels of reactive oxygen species (ROS) in RPE and inflammatory cytokines in RPE and serum. With respect to gut microbiome, we found that organisms abundant in the high fat condition (e.g. in the genus Anaerotruncus and Oscillospira) and implicated in AMD, were much less abundant after etifoxine treatment. The changes in gut flora were associated with the predicted production of metabolites of benefit to the retina including tryptophan and other amino acids and taurine, an essential component of the retina necessary to counteract ROS. These novel observations strengthen earlier conclusions that the mechanisms behind improvements in etifoxine-induced retinal physiology involve an interaction between effects on the host and the gut microbiome.
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Affiliation(s)
- Lincoln Biswas
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, UK
| | - Khalid Subhi Ibrahim
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, UK; Department of Biology, Faculty of Science, University of Zakho, Kurdistan Region, Iraq
| | - Xing Li
- School of Basic Medical Sciences, Shaoyang University, Shaoyang, 422000, China
| | - Xinzhi Zhou
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, UK
| | - Zhihong Zeng
- College of Biological and Environmental Engineering, Changsha University, Changsha, Hunan, 410022, PR China
| | - John Craft
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, UK
| | - Xinhua Shu
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, UK; Department of Vision Science, Glasgow Caledonian University, UK; School of Basic Medical Sciences, Shaoyang University, Shaoyang, 422000, China.
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17
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Singh LP, Yumnamcha T, Devi TS. Mitophagy, Ferritinophagy and Ferroptosis in Retinal Pigment Epithelial Cells Under High Glucose Conditions: Implications for Diabetic Retinopathy and Age-Related Retinal Diseases. JOJ OPHTHALMOLOGY 2021; 8:77-85. [PMID: 35187384 PMCID: PMC8856657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Diabetic retinopathy (DR) is a devastating disease leading to blindness among majority of working adults around the globe. Nonetheless, an effective treatment or cure for the disease is still to be achieved. This is because the cellular and molecular mechanisms of DR are complex and not fully understood yet. In this article, we describe how high glucose induced TXNIP upregulation and associated redox stress may cause mitochondrial dysfunction, mitophagy, ferritinophagy (iron release by autophagy) and lysosome destabilization. Labile irons react with hydrogen peroxide (H2O2) to generate hydroxyl radicals (.OH) by the Fenton reaction and cause membrane phospholipid peroxidation due to reduction in glutathione (GSH) level and glutathione peroxidase 4 (GPX4) activity, which cause ferroptosis, a recently identified non-apoptotic cell death mechanism. We used in this study a retinal pigment epithelial cell line, ARPE- 19 and exposed it to high glucose in in vitro cultures to highlight some of the intricacies of these cellular processes, which may be relevant to the pathogenesis of DR and age-related retinal neurodegenerative diseases, such as age-related macular degeneration, AMD.
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Affiliation(s)
- Lalit Pukhrambam Singh
- Corresponding author: Lalit Pukhrambam Singh, Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine Detroit, MI 48201, USA
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18
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Retinal pigment epithelial cells secrete miR-202-5p-containing exosomes to protect against proliferative diabetic retinopathy. Exp Eye Res 2020; 201:108271. [PMID: 33007305 DOI: 10.1016/j.exer.2020.108271] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/13/2020] [Accepted: 09/20/2020] [Indexed: 12/12/2022]
Abstract
Previous studies have reported that endothelial-to-mesenchymal transition (EndoMT) contributes to pathological fibrosis in proliferative diabetic retinopathy (PDR). The hypothesis of our study was that exosomes from high glucose (HG)-treated ARPE19 cells reprogram endothelial cell behavior in HG conditions by transferring their genetic contents. Our study showed that ARPE19-derived exosomes were internalized by human umbilical vein endothelial cells (HUVECs). Additionally, miR-202-5p, a miRNA known to target TGFβR2, was enriched in ARPE19-derived exosomes. A dual luciferase reporter assay, qPCR, and western blotting were used to characterize the expression of miR-202-5p and phosphorylation of the TGF/Smad pathway proteins. We showed that miR-202-5p-containing exosomes suppressed HUVEC cell growth, migration, and tube formation. Furthermore, TGFβR2 was confirmed as the target of miR-202-5p. A dual luciferase reporter assay showed that TGFβR2 expression was negatively regulated by miR-202-5p. We also showed that miR-202-5p-containing exosomes suppressed HG-induced EndoMT. These collective results suggested that ARPE-derived exosomes may serve as significant mediators of cell-to-cell crosstalk to suppress EndoMT by transferring miR-202-5p through the TGF/Smad pathway, and may be a potential treatment for PDR patients.
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19
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Muns SM, Montalvo LA, Vargas Del Valle JG, Martinez M, Oliver AL, Izquierdo NJ. Clinical characteristics and ultra-widefield fundus image analysis of two siblings with Bardet-Biedl syndrome type 1 p.Met390Arg variant. Am J Ophthalmol Case Rep 2020; 20:100914. [PMID: 33015405 PMCID: PMC7522087 DOI: 10.1016/j.ajoc.2020.100914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/09/2020] [Accepted: 08/31/2020] [Indexed: 12/15/2022] Open
Abstract
Purpose To present the case of two siblings with a genetic diagnosis of Bardet Biedl syndrome (BBS) type 1, yet different clinical profiles and disease manifestations. Observations Sequencing analysis revealed a p.Met390Arg pathogenic variant in the BBS1 gene of both patients, as well as several additional variants of uncertain significance Patient 1 was 41 years old, had three primary (cone-rod dystrophy, hypogonadism, and truncal obesity) and three secondary (arterial hypertension, strabismus, and astigmatism) BBS features. He also had insulin resistance, as well as low levels of total testosterone and cortisol. Patient 2 was 43 years old, had two primary (cone-rod dystrophy and truncal obesity), and four secondary (arterial hypertension, diabetes mellitus, strabismus, and astigmatism) BBS features. Both patients had severe maculopathy; however, patient 1 had bone-spicules that extended up to the mid-periphery, in a perivenular pattern, and significant vascular attenuation with "ghost vessel" appearance towards the temporal periphery, a feature that was absent on patient 2. Conclusions and Importance The intrafamilial phenotypic variability among our patients supports the hypothesis that BBS is a disease with genetic, hormonal, and environmental triggers interacting to produce phenotypic variability. Although our report may not establish a definite relationship between environmental and genetic influences, their role should be explored in future studies.
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Affiliation(s)
- Sofia M Muns
- University of Puerto Rico School of Medicine, Medical Sciences Campus, San Juan, PR, 00936-5067, USA
| | - Lorena A Montalvo
- Department of Ophthalmology, University of Puerto Rico School of Medicine, Medical Sciences Campus, San Juan, PR, 00936-5067, USA
| | - Jose G Vargas Del Valle
- University of Puerto Rico School of Medicine, Medical Sciences Campus, San Juan, PR, 00936-5067, USA
| | - Meliza Martinez
- Endocrinology, Diabetes and Metabolism Section, Department of Internal Medicine, University of Puerto Rico School of Medicine, Medical Sciences Campus, San Juan, PR, 00936-5067, USA
| | - Armando L Oliver
- Department of Ophthalmology, University of Puerto Rico School of Medicine, Medical Sciences Campus, San Juan, PR, 00936-5067, USA
| | - Natalio J Izquierdo
- Department of Surgery, University of Puerto Rico School of Medicine, Medical Sciences Campus, San Juan, PR, 00936-5067, USA
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20
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Abstract
Patients with diabetes continue to suffer from impaired visual performance before the appearance of overt damage to the retinal microvasculature and later sight-threatening complications. This diabetic retinopathy (DR) has long been thought to start with endothelial cell oxidative stress. Yet newer data surprisingly finds that the avascular outer retina is the primary site of oxidative stress before microvascular histopathology in experimental DR. Importantly, correcting this early oxidative stress is sufficient to restore vision and mitigate the histopathology in diabetic models. However, translating these promising results into the clinic has been stymied by an absence of methods that can measure and optimize anti-oxidant treatment efficacy in vivo. Here, we review imaging approaches that address this problem. In particular, diabetes-induced oxidative stress impairs dark-light regulation of subretinal space hydration, which regulates the distribution of interphotoreceptor binding protein (IRBP). IRBP is a vision-critical, anti-oxidant, lipid transporter, and pro-survival factor. We show how optical coherence tomography can measure subretinal space oxidative stress thus setting the stage for personalizing anti-oxidant treatment and prevention of impactful declines and loss of vision in patients with diabetes.
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21
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Donato L, Scimone C, Alibrandi S, Rinaldi C, Sidoti A, D’Angelo R. Transcriptome Analyses of lncRNAs in A2E-Stressed Retinal Epithelial Cells Unveil Advanced Links between Metabolic Impairments Related to Oxidative Stress and Retinitis Pigmentosa. Antioxidants (Basel) 2020; 9:E318. [PMID: 32326576 PMCID: PMC7222347 DOI: 10.3390/antiox9040318] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 04/08/2020] [Accepted: 04/14/2020] [Indexed: 12/12/2022] Open
Abstract
: Long non-coding RNAs (lncRNAs) are untranslated transcripts which regulate many biological processes. Changes in lncRNA expression pattern are well-known related to various human disorders, such as ocular diseases. Among them, retinitis pigmentosa, one of the most heterogeneous inherited disorder, is strictly related to oxidative stress. However, little is known about regulative aspects able to link oxidative stress to etiopathogenesis of retinitis. Thus, we realized a total RNA-Seq experiment, analyzing human retinal pigment epithelium cells treated by the oxidant agent N-retinylidene-N-retinylethanolamine (A2E), considering three independent experimental groups (untreated control cells, cells treated for 3 h and cells treated for 6 h). Differentially expressed lncRNAs were filtered out, explored with specific tools and databases, and finally subjected to pathway analysis. We detected 3,3'-overlapping ncRNAs, 107 antisense, 24 sense-intronic, four sense-overlapping and 227 lincRNAs very differentially expressed throughout all considered time points. Analyzed lncRNAs could be involved in several biochemical pathways related to compromised response to oxidative stress, carbohydrate and lipid metabolism impairment, melanin biosynthetic process alteration, deficiency in cellular response to amino acid starvation, unbalanced regulation of cofactor metabolic process, all leading to retinal cell death. The explored lncRNAs could play a relevant role in retinitis pigmentosa etiopathogenesis, and seem to be the ideal candidate for novel molecular markers and therapeutic strategies.
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Affiliation(s)
- Luigi Donato
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98125 Messina, Italy
- Department of Biomolecular Strategies, Genetics and Avant-Garde Therapies, I.E.ME.S.T., 90139 Palermo, Italy
| | - Concetta Scimone
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98125 Messina, Italy
- Department of Biomolecular Strategies, Genetics and Avant-Garde Therapies, I.E.ME.S.T., 90139 Palermo, Italy
| | - Simona Alibrandi
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98125 Messina, Italy
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98125 Messina, Italy
| | - Carmela Rinaldi
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98125 Messina, Italy
| | - Antonina Sidoti
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98125 Messina, Italy
- Department of Biomolecular Strategies, Genetics and Avant-Garde Therapies, I.E.ME.S.T., 90139 Palermo, Italy
| | - Rosalia D’Angelo
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98125 Messina, Italy
- Department of Biomolecular Strategies, Genetics and Avant-Garde Therapies, I.E.ME.S.T., 90139 Palermo, Italy
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22
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Elucidating the mechanism of action of alpha-1-antitrypsin using retinal pigment epithelium cells exposed to high glucose. Potential use in diabetic retinopathy. PLoS One 2020; 15:e0228895. [PMID: 32032388 PMCID: PMC7006930 DOI: 10.1371/journal.pone.0228895] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 01/24/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Alpha-1-antitrypsin is a protein involved in avoidance of different processes that are seen in diabetic retinopathy pathogenesis. These processes include apoptosis, extracellular matrix remodeling and damage of vessel walls and capillaries. Furthermore, because of its anti-inflammatory effects, alpha-1-antitrypsin has been proposed as a possible therapeutic approach for diabetic retinopathy. Our group tested alpha-1-antitrypsin in a type 1 diabetes mouse model and observed a reduction of inflammation and retinal neurodegeneration. Thus, shedding light on the mechanism of action of alpha-1-antitrypsin at molecular level may explain how it works in the diabetic retinopathy context and show its potential for use in other retinal diseases. METHODS In this work, we evaluated alpha-1-antitrypsin in an ARPE-19 human cell line exposed to high glucose. We explored the expression of different mediators on signaling pathways related to pro-inflammatory cytokines production, glucose metabolism, epithelial-mesenchymal transition and other proteins involved in the normal function of retinal pigment epithelium by RT-qPCR and Western Blot. RESULTS We obtained different expression patterns for evaluated mediators altered with high glucose exposure and corrected with the use of alpha-1-antitrypsin. CONCLUSIONS The expression profile obtained in vitro for the evaluated proteins and mRNA allowed us to explain our previous results obtained on mouse models and to hypothesize how alpha-1-antitrypsin hinder diabetic retinopathy progression on a complex network between different signaling pathways. GENERAL SIGNIFICANCE This network helps to understand the way alpha-1-antitrypsin works in diabetic retinopathy and its scope of action.
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23
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Jiang Y, Liu L, Li H, Wang JM, Steinle JJ. Insulin Signal Transduction is Impaired in the Type 2 Diabetic Retina. JOURNAL OF DIABETES AND CLINICAL RESEARCH 2020; 2:12-15. [PMID: 32432228 PMCID: PMC7236787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Rates of type 2 diabetes are reaching epidemic levels. Yet, the tissue specific alterations due to insulin resistance are only recently being investigated. The goal of the present study was to evaluate retinal insulin signal transduction in a common mouse model of type 2 diabetes, the db/db mouse. Retinal lysates from five month old male db/db and db/+ (control) mice were collected and processed for Western blotting or ELISA analyses for insulin receptor, insulin receptor substrate-1 (IRS-1), Akt, tumor necrosis factor alpha (TNFα) and caspase 3 levels. Data demonstrate increased TNFα and IRS-1 phosphorylation on serine 307. This led to decreased Akt phosphorylation on serine 473 and increased cleavage of caspase 3. Taken together, the data suggest dysfunctional insulin signaling in the retina of the db/db mouse. insulin.
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Affiliation(s)
- Youde Jiang
- Department of Ophthalmology, Visual, and Anatomical Sciences, Wayne State University, Detroit, MI USA
| | - Li Liu
- Department of Ophthalmology, Visual, and Anatomical Sciences, Wayne State University, Detroit, MI USA
| | - Hainan Li
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI USA
| | - Jie-Mei Wang
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI USA
| | - Jena J. Steinle
- Department of Ophthalmology, Visual, and Anatomical Sciences, Wayne State University, Detroit, MI USA,Correspondence should be addressed to Jena J. Steinle;
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24
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Yumnamcha T, Devi TS, Singh LP. Auranofin Mediates Mitochondrial Dysregulation and Inflammatory Cell Death in Human Retinal Pigment Epithelial Cells: Implications of Retinal Neurodegenerative Diseases. Front Neurosci 2019; 13:1065. [PMID: 31649499 PMCID: PMC6795687 DOI: 10.3389/fnins.2019.01065] [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: 07/31/2019] [Accepted: 09/24/2019] [Indexed: 12/22/2022] Open
Abstract
Purpose Photoreceptor degeneration occurs in various retinal diseases including age-related macular degeneration (AMD), Retinitis pigmentosa (RP), and diabetic retinopathy (DR). However, molecular mechanisms are not fully understood yet. The retinal pigment epithelium (RPE) forms the outer blood retinal barrier (oBRB) and supplies glucose, oxygen and nutrients from the fenestrated choriocapillaris to photoreceptors for visual function. Therefore, RPE dysfunction leads to photoreceptor injury/death and progression of blinding eye diseases. This study aims to understand the role of the thioredoxin (Trx) and its reductase (TrxR) redox signaling in human RPE dysfunction and cell death mechanism(s) in an in vitro system. Methods A human RPE cell line (APRE-19) was cultured in DMEM/F12 medium and treated with auranofin (AF - 4 μM, an inhibitor of TrxR) for 4 and 24 h. Mitochondrial and lysosomal function, cellular oxidative stress and NLRP3 inflammasome activity were measured using cell assays, Western blotting, and confocal microscopy. Antioxidants and anti-inflammatory compounds were tested for blocking AF effects on RPE damage. Cell death mechanisms (LDH release to culture media) were determined using necroptosis, ferroptosis and pyroptosis inhibitors. P < 0.05 was considered significant in statistical analysis. Results Auranofin causes mitochondrial dysfunction (Δψm↓ and ATP↓), oxidative stress (H2O2↑) and mitophagic flux to lysosomes. Furthermore, the lysosomal enzyme (cathepsin L) activity is reduced while that of pro-inflammatory caspase-1 (NLRP3 inflammasome) is enhanced in ARPE-19. These effects of AF on ARPE-19 are inhibited by antioxidant N-acetylcysteine (5 mM, NAC) and significantly by a combination of SS31 (mitochondrial antioxidant) and anti-inflammatory drugs (amlexanox and tranilast). AF also causes cell death as measured by cytosolic LDH release/leakage, which is not inhibited by either ferrostatin-1 or necrostatin-1 (ferroptosis and necroptosis inhibitors, respectively). Conversely, AF-induced LDH release is significantly reduced by MCC950 and Ac-YVAD-cmk (NLRP3 and Caspase-1 inhibitors, respectively), suggesting a pro-inflammatory cell death by pyroptosis. Conclusion The Trx/TrxR redox system is critical for RPE function and viability. We previously showed that thioredoxin-interacting protein (TXNIP) is strongly induced in DR inhibiting the Trx/TrxR system and RPE dysfunction. Therefore, our results suggest that the TXNIP-Trx-TrxR redox pathway may participate in RPE dysfunction in DR and other retinal neurodegenerative diseases.
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Affiliation(s)
- Thangal Yumnamcha
- Department of Ophthalmology, Visual and Anatomical Sciences (OVAS), Wayne State University School of Medicine, Detroit, MI, United States
| | - Takhellembam Swornalata Devi
- Department of Ophthalmology, Visual and Anatomical Sciences (OVAS), Wayne State University School of Medicine, Detroit, MI, United States
| | - Lalit Pukhrambam Singh
- Department of Ophthalmology, Visual and Anatomical Sciences (OVAS), Wayne State University School of Medicine, Detroit, MI, United States
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25
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Compromised Barrier Function in Human Induced Pluripotent Stem-Cell-Derived Retinal Pigment Epithelial Cells from Type 2 Diabetic Patients. Int J Mol Sci 2019; 20:ijms20153773. [PMID: 31375001 PMCID: PMC6696227 DOI: 10.3390/ijms20153773] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/23/2019] [Accepted: 08/01/2019] [Indexed: 12/14/2022] Open
Abstract
In diabetic patients, high blood glucose induces alterations in retinal function and can lead to visual impairment due to diabetic retinopathy. In immortalized retinal pigment epithelial (RPE) cultures, high glucose concentrations are shown to lead to impairment in epithelial barrier properties. For the first time, the induced pluripotent stem-cell-derived retinal pigment epithelium (hiPSC-RPE) cell lines derived from type 2 diabetics and healthy control patients were utilized to assess the effects of glucose concentration on the cellular functionality. We show that both type 2 diabetic and healthy control hiPSC-RPE lines differentiate and mature well, both in high and normal glucose concentrations, express RPE specific genes, secrete pigment epithelium derived factor, and form a polarized cell layer. Here, type 2 diabetic hiPSC-RPE cells had a decreased barrier function compared to controls. Added insulin increased the epithelial cell layer tightness in normal glucose concentrations, and the effect was more evident in type 2 diabetics than in healthy control hiPSC-RPE cells. In addition, the preliminary functionality assessments showed that type 2 diabetic hiPSC-RPE cells had attenuated autophagy detected via ubiquitin-binding protein p62/Sequestosome-1 (p62/SQSTM1) accumulation, and lowered pro- matrix metalloproteinase 2 (proMMP2) as well as increased pro-MMP9 secretion. These results suggest that the cellular ability to tolerate stress is possibly decreased in type 2 diabetic RPE cells.
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26
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Neuroprotective Peptides in Retinal Disease. J Clin Med 2019; 8:jcm8081146. [PMID: 31374938 PMCID: PMC6722704 DOI: 10.3390/jcm8081146] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 07/26/2019] [Accepted: 07/31/2019] [Indexed: 02/07/2023] Open
Abstract
In the pathogenesis of many disorders, neuronal death plays a key role. It is now assumed that neurodegeneration is caused by multiple and somewhat converging/overlapping death mechanisms, and that neurons are sensitive to unique death styles. In this respect, major advances in the knowledge of different types, mechanisms, and roles of neurodegeneration are crucial to restore the neuronal functions involved in neuroprotection. Several novel concepts have emerged recently, suggesting that the modulation of the neuropeptide system may provide an entirely new set of pharmacological approaches. Neuropeptides and their receptors are expressed widely in mammalian retinas, where they exert neuromodulatory functions including the processing of visual information. In multiple models of retinal diseases, different peptidergic substances play neuroprotective actions. Herein, we describe the novel advances on the protective roles of neuropeptides in the retina. In particular, we focus on the mechanisms by which peptides affect neuronal death/survival and the vascular lesions commonly associated with retinal neurodegenerative pathologies. The goal is to highlight the therapeutic potential of neuropeptide systems as neuroprotectants in retinal diseases.
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27
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Pujol-Lereis LM. Alteration of Sphingolipids in Biofluids: Implications for Neurodegenerative Diseases. Int J Mol Sci 2019; 20:ijms20143564. [PMID: 31330872 PMCID: PMC6678458 DOI: 10.3390/ijms20143564] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 07/12/2019] [Accepted: 07/13/2019] [Indexed: 12/14/2022] Open
Abstract
Sphingolipids (SL) modulate several cellular processes including cell death, proliferation and autophagy. The conversion of sphingomyelin (SM) to ceramide and the balance between ceramide and sphingosine-1-phosphate (S1P), also known as the SL rheostat, have been associated with oxidative stress and neurodegeneration. Research in the last decade has focused on the possibility of targeting the SL metabolism as a therapeutic option; and SL levels in biofluids, including serum, plasma, and cerebrospinal fluid (CSF), have been measured in several neurodegenerative diseases with the aim of finding a diagnostic or prognostic marker. Previous reviews focused on results from diseases such as Alzheimer's Disease (AD), evaluated total SL or species levels in human biofluids, post-mortem tissues and/or animal models. However, a comprehensive review of SL alterations comparing results from several neurodegenerative diseases is lacking. The present work compiles data from circulating sphingolipidomic studies and attempts to elucidate a possible connection between certain SL species and neurodegeneration processes. Furthermore, the effects of ceramide species according to their acyl-chain length in cellular pathways such as apoptosis and proliferation are discussed in order to understand the impact of the level alteration in specific species. Finally, enzymatic regulations and the possible influence of insulin resistance in the level alteration of SL are evaluated.
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Affiliation(s)
- Luciana M Pujol-Lereis
- Centro de Investigación y Desarrollo en Inmunología y Enfermedades Infecciosas (CIDIE-CONICET), X5016DHK Córdoba, Argentina.
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28
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Nawaz IM, Rezzola S, Cancarini A, Russo A, Costagliola C, Semeraro F, Presta M. Human vitreous in proliferative diabetic retinopathy: Characterization and translational implications. Prog Retin Eye Res 2019; 72:100756. [PMID: 30951889 DOI: 10.1016/j.preteyeres.2019.03.002] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 03/26/2019] [Accepted: 03/28/2019] [Indexed: 02/07/2023]
Abstract
Diabetic retinopathy (DR) is one of the leading causes of visual impairment in the working-age population. DR is a progressive eye disease caused by long-term accumulation of hyperglycaemia-mediated pathological alterations in the retina of diabetic patients. DR begins with asymptomatic retinal abnormalities and may progress to advanced-stage proliferative diabetic retinopathy (PDR), characterized by neovascularization or preretinal/vitreous haemorrhages. The vitreous, a transparent gel that fills the posterior cavity of the eye, plays a vital role in maintaining ocular function. Structural and molecular alterations of the vitreous, observed during DR progression, are consequences of metabolic and functional modifications of the retinal tissue. Thus, vitreal alterations reflect the pathological events occurring at the vitreoretinal interface. These events are caused by hypoxic, oxidative, inflammatory, neurodegenerative, and leukostatic conditions that occur during diabetes. Conversely, PDR vitreous can exert pathological effects on the diabetic retina, resulting in activation of a vicious cycle that contributes to disease progression. In this review, we recapitulate the major pathological features of DR/PDR, and focus on the structural and molecular changes that characterize the vitreal structure and composition during DR and progression to PDR. In PDR, vitreous represents a reservoir of pathological signalling molecules. Therefore, in this review we discuss how studying the biological activity of the vitreous in different in vitro, ex vivo, and in vivo experimental models can provide insights into the pathogenesis of PDR. In addition, the vitreous from PDR patients can represent a novel tool to obtain preclinical experimental evidences for the development and characterization of new therapeutic drug candidates for PDR therapy.
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Affiliation(s)
- Imtiaz M Nawaz
- Department of Molecular and Translational Medicine, University of Brescia, Italy
| | - Sara Rezzola
- Department of Molecular and Translational Medicine, University of Brescia, Italy
| | - Anna Cancarini
- Department of Ophthalmology, University of Brescia, Italy
| | - Andrea Russo
- Department of Ophthalmology, University of Brescia, Italy
| | - Ciro Costagliola
- Department of Medicine and Health Sciences, University of Molise, Campobasso, Italy
| | | | - Marco Presta
- Department of Molecular and Translational Medicine, University of Brescia, Italy.
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