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Wei C, Fu M, Zhang H, Yao B. How is the P2X7 receptor signaling pathway involved in epileptogenesis? Neurochem Int 2024; 173:105675. [PMID: 38211839 DOI: 10.1016/j.neuint.2024.105675] [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: 09/21/2023] [Revised: 12/22/2023] [Accepted: 01/03/2024] [Indexed: 01/13/2024]
Abstract
Epilepsy, a condition characterized by spontaneous recurrent epileptic seizures, is among the most prevalent neurological disorders. This disorder is estimated to affect approximately 70 million people worldwide. Although antiseizure medications are considered the first-line treatments for epilepsy, most of the available antiepileptic drugs are not effective in nearly one-third of patients. This calls for the development of more effective drugs. Evidence from animal models and epilepsy patients suggests that strategies that interfere with the P2X7 receptor by binding to adenosine triphosphate (ATP) are potential treatments for this patient population. This review describes the role of the P2X7 receptor signaling pathways in epileptogenesis. We highlight the genes, purinergic signaling, Pannexin1, glutamatergic signaling, adenosine kinase, calcium signaling, and inflammatory response factors involved in the process, and conclude with a synopsis of these key connections. By unraveling the intricate interplay between P2X7 receptors and epileptogenesis, this review provides ideas for designing potent clinical therapies that will revolutionize both prevention and treatment for epileptic patients.
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Affiliation(s)
- Caichuan Wei
- Department of Pediatrics, Renmin Hospital of Wuhan University, 99 Zhang Zhidong Road, Wuchang District, Wuhan, Hubei Province 430060, China
| | - Miaoying Fu
- Department of Pediatrics, Renmin Hospital of Wuhan University, 99 Zhang Zhidong Road, Wuchang District, Wuhan, Hubei Province 430060, China
| | - Haiju Zhang
- Department of Pediatrics, Renmin Hospital of Wuhan University, 99 Zhang Zhidong Road, Wuchang District, Wuhan, Hubei Province 430060, China
| | - Baozhen Yao
- Department of Pediatrics, Renmin Hospital of Wuhan University, 99 Zhang Zhidong Road, Wuchang District, Wuhan, Hubei Province 430060, China.
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2
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Liu S, Zhang W. NAD + metabolism and eye diseases: current status and future directions. Mol Biol Rep 2023; 50:8653-8663. [PMID: 37540459 DOI: 10.1007/s11033-023-08692-y] [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: 05/16/2023] [Accepted: 07/18/2023] [Indexed: 08/05/2023]
Abstract
Currently, there are no truly effective treatments for a variety of eye diseases, such as glaucoma, age-related macular degeneration (AMD), and inherited retinal degenerations (IRDs). These conditions have a significant impact on patients' quality of life and can be a burden on society. However, these diseases share a common pathological process of NAD+ metabolism disorders. They are either associated with genetically induced primary NAD+ synthase deficiency, decreased NAD+ levels due to aging, or enhanced NAD+ consuming enzyme activity during disease pathology. In this discussion, we explore the role of NAD+ metabolic disorders in the development of associated ocular diseases and the potential advantages and disadvantages of various methods to increase NAD+ levels. It is essential to carefully evaluate the possible adverse effects of these methods and conduct a more comprehensive and objective assessment of their function before considering their use.
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Affiliation(s)
- Siyuan Liu
- Department of Ophthalmology, Second Clinical Medical College, Lanzhou University, 730030, Lanzhou, VA, China
| | - Wenfang Zhang
- Department of Ophthalmology, The Second Hospital of Lanzhou University, 730030, Lanzhou, VA, China.
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3
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Miller AL, James RE, Harvey AR, Trifunović D, Carvalho LS. The role of epigenetic changes in the pathology and treatment of inherited retinal diseases. Front Cell Dev Biol 2023; 11:1224078. [PMID: 37601102 PMCID: PMC10436478 DOI: 10.3389/fcell.2023.1224078] [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: 05/17/2023] [Accepted: 07/20/2023] [Indexed: 08/22/2023] Open
Abstract
Elucidation of the cellular changes that occur in degenerating photoreceptors of people with inherited retinal diseases (IRDs) has been a focus for many research teams, leading to numerous theories on how these changes affect the cell death process. What is clearly emerging from these studies is that there are common denominators across multiple models of IRD, regardless of the underlying genetic mutation. These common markers could open avenues for broad neuroprotective therapeutics to prevent photoreceptor loss and preserve functional vision. In recent years, the role of epigenetic modifications contributing to the pathology of IRDs has been a particular point of interest, due to many studies noting changes in these epigenetic modifications, which coincide with photoreceptor cell death. This review will discuss the two broad categories of epigenetic changes, DNA methylation and histone modifications, that have received particular attention in IRD models. We will review the altered epigenetic regulatory events that are believed to contribute to cell death in IRDs and discuss the therapeutic potential of targeting these alterations.
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Affiliation(s)
- Annie L. Miller
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, WA, Australia
- Retinal Genomics and Therapy Laboratory, Lions Eye Institute, Nedlands, WA, Australia
| | - Rebekah E. James
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, WA, Australia
- Retinal Genomics and Therapy Laboratory, Lions Eye Institute, Nedlands, WA, Australia
| | - Alan R. Harvey
- Retinal Genomics and Therapy Laboratory, Lions Eye Institute, Nedlands, WA, Australia
- School of Human Sciences, The University of Western Australia, Crawley, WA, Australia
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia
| | - Dragana Trifunović
- Institute for Ophthalmic Research, Tubingen University, Tübingen, Germany
| | - Livia S. Carvalho
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, WA, Australia
- Retinal Genomics and Therapy Laboratory, Lions Eye Institute, Nedlands, WA, Australia
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC, Australia
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4
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Chen Y, Zizmare L, Trautwein C, Paquet-Durand F. Measuring the Release of Lactate from Wild-Type and rd1 Mouse Retina. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:429-434. [PMID: 37440068 DOI: 10.1007/978-3-031-27681-1_63] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
The retina has the highest energy consumption of any tissue in the human body. Remarkably, to satisfy its energy demand, the retina appears to rely mostly on aerobic glycolysis, which results in the production and release of large amounts of lactate. In the present study, we compared two different methods to assess lactate release from in vitro organotypic retinal explants cultured under entirely controlled, serum-free conditions. We used a standard lactate assay kit and 1H-nuclear magnetic resonance (NMR) spectroscopy-based analysis. We found that during the culturing of retinal explants derived from wild-type mice, lactate was released in large amounts and that the two different methods agreed well with each other. When comparing wild-type retina with degenerating rd1 mouse retina, we found the latter to release significantly higher amounts of lactate. Hence, degenerating retina may have an even higher energy demand and metabolic rate compared to healthy retina. We conclude that the use of lactate measurement can be a reliable and simple readout to evaluate ongoing retinal metabolism.
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Affiliation(s)
- Yiyi Chen
- Cell Death Mechanism Group, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Laimdota Zizmare
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, University of Tübingen, Tübingen, Germany
| | - Christoph Trautwein
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, University of Tübingen, Tübingen, Germany
| | - François Paquet-Durand
- Cell Death Mechanism Group, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.
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5
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Yang P, Lockard R, Titus H, Hiblar J, Weller K, Wafai D, Weleber RG, Duvoisin RM, Morgans CW, Pennesi ME. Suppression of cGMP-Dependent Photoreceptor Cytotoxicity With Mycophenolate Is Neuroprotective in Murine Models of Retinitis Pigmentosa. Invest Ophthalmol Vis Sci 2021; 61:25. [PMID: 32785677 PMCID: PMC7441375 DOI: 10.1167/iovs.61.10.25] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Purpose To determine the effect of mycophenolate mofetil (MMF) on retinal degeneration on two mouse models of retinitis pigmentosa. Methods Intraperitoneal injections of MMF were administered daily in rd10 and c57 mice starting at postoperative day 12 (P12) and rd1 mice starting at P8. The effect of MMF was assessed with optical coherence tomography, immunohistochemistry, electroretinography, and OptoMotry. Whole retinal cyclic guanosine monophosphate (cGMP) and mycophenolic acid levels were quantified with mass spectrometry. Photoreceptor cGMP cytotoxicity was evaluated with cell counts of cGMP immunostaining. Results MMF treatment significantly delays the onset of retinal degeneration and cGMP-dependent photoreceptor cytotoxicity in rd10 and rd1 mice, albeit a more modest effect in the latter. In rd10 mice, treatment with MMF showed robust preservation of the photoreceptors up to P22 with associated suppression of cGMP immunostaining and microglial activation; The neuroprotective effect diminished after P22, but outer retinal thickness was still significantly thicker by P35 and OptoMotry response was significantly better up to P60. Whereas cGMP immunostaining of the photoreceptors were present in rd10 and rd1 mice, hyperphysiological whole retinal cGMP levels were observed only in rd1 mice. Conclusions Early treatment with MMF confers potent neuroprotection in two animal models of RP by suppressing the cGMP-dependent common pathway for photoreceptor cell death. The neuroprotective effect of MMF on cGMP-dependent cytotoxicity occurs independently of the presence of hyperphysiological whole retinal cGMP levels. Thus our data suggest that MMF may be an important new class of neuroprotective agent that could be useful in the treatment of patients with RP.
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Affiliation(s)
- Paul Yang
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Rachel Lockard
- School of Medicine, Oregon Health & Science University, Portland, Oregon, United States
| | - Hope Titus
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Jordan Hiblar
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Kyle Weller
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Dahlia Wafai
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Richard G Weleber
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Robert M Duvoisin
- Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, Oregon, United States
| | - Catherine W Morgans
- Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, Oregon, United States
| | - Mark E Pennesi
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
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6
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Alarautalahti V, Ragauskas S, Hakkarainen JJ, Uusitalo-Järvinen H, Uusitalo H, Hyttinen J, Kalesnykas G, Nymark S. Viability of Mouse Retinal Explant Cultures Assessed by Preservation of Functionality and Morphology. Invest Ophthalmol Vis Sci 2019; 60:1914-1927. [PMID: 31042799 DOI: 10.1167/iovs.18-25156] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Retinal explant cultures provide simplified systems where the functions of the retina and the effects of ocular therapies can be studied in an isolated environment. The purpose of this study was to provide insight into long-term preservation of retinal tissue in culture conditions, enable a deeper understanding of the interdependence of retinal morphology and function, and ensure the reliability of the explant technique for prolonged experiments. Methods Retinal explants from adult mice were cultured as organotypic culture at the air-medium interface for 14 days in vitro (DIV). Retinal functionality was assessed by multielectrode array technique and morphology by immunohistochemical methods at several time points during culture. Results Retinal explants retained viability for 14 DIV, although with diminishing neuronal activity, progressing neuronal loss, and increasing reactive gliosis. We recorded spontaneous retinal ganglion cell (RGC) activity up to 14 DIV with temporally changing distribution of RGC firing rates. Light responsiveness was measurable from RGCs for 7 DIV and from photoreceptors for 2 DIV. Apoptotic cells were detected beginning at 3 DIV with their density peaking at 7 DIV. The number of RGCs gradually decreased by 70% during 14 DIV. The change was accompanied by the loss of RGC functionality, resulting in 84% loss of electrically active RGCs. Conclusions Retinal explants provide a valuable tool for studies of retinal functions and development of ocular therapies. However, critical for long-term use, retinal functionality was lost before structural loss, emphasizing a need for both functional and morphologic readouts to determine the overall state of the cultured retina.
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Affiliation(s)
- Virpi Alarautalahti
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | | | | | - Hannele Uusitalo-Järvinen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.,Tays Eye Centre, Tampere University Hospital, Tampere, Finland
| | - Hannu Uusitalo
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.,Tays Eye Centre, Tampere University Hospital, Tampere, Finland
| | - Jari Hyttinen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | | | - Soile Nymark
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
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7
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Poly ADP ribosylation and extracellular vesicle activity in rod photoreceptor degeneration. Sci Rep 2019; 9:3758. [PMID: 30842506 PMCID: PMC6403254 DOI: 10.1038/s41598-019-40215-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 02/07/2019] [Indexed: 01/28/2023] Open
Abstract
Retinitis Pigmentosa is a group of inherited neurodegenerative diseases that result in selective cell death of photoreceptors. In the developed world, RP is regarded as the main cause of blindness among the working age population. The precise mechanisms eventually leading to cell death remain unknown and to date no adequate treatment for RP is available. Poly ADP ribose polymerase (PARP) over activity is involved in photoreceptor degeneration and pharmacological inhibition or genetic knock-down PARP1 activity protect photoreceptors in mice models, the mechanism of neuroprotection is not clear yet. Our result indicated that olaparib, a PARP1 inhibitor, significantly rescued photoreceptor cells in rd10 retina. Extracellular vesicles (EVs) were previously recognized as a mechanism for discharging useless cellular components. Growing evidence has elucidated their roles in cell-cell communication by carrying nucleic acids, proteins and lipids that can, in turn, regulate behavior of the target cells. Recent research suggested that EVs extensively participate in progression of diverse blinding diseases, such as age-related macular (AMD) degeneration. Our study demonstrates the involvement of EVs activity in the process of photoreceptor degeneration in a PDE6 mutation. PARP inhibition protects photoreceptors via regulation of the EVs activity in rod photoreceptor degeneration in a PDE6b mutation.
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8
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Lin JB, Apte RS. NAD + and sirtuins in retinal degenerative diseases: A look at future therapies. Prog Retin Eye Res 2018; 67:118-129. [PMID: 29906612 PMCID: PMC6235699 DOI: 10.1016/j.preteyeres.2018.06.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 06/08/2018] [Accepted: 06/11/2018] [Indexed: 12/19/2022]
Abstract
Retinal degenerative diseases are a major cause of morbidity in modern society because visual impairment significantly decreases the quality of life of patients. A significant challenge in treating retinal degenerative diseases is their genetic and phenotypic heterogeneity. However, despite this diversity, many of these diseases share a common endpoint involving death of light-sensitive photoreceptors. Identifying common pathogenic mechanisms that contribute to photoreceptor death in these diverse diseases may lead to a unifying therapy for multiple retinal diseases that would be highly innovative and address a great clinical need. Because the retina and photoreceptors, in particular, have immense metabolic and energetic requirements, many investigators have hypothesized that metabolic dysfunction may be a common link unifying various retinal degenerative diseases. Here, we discuss a new area of research examining the role of NAD+ and sirtuins in regulating retinal metabolism and in the pathogenesis of retinal degenerative diseases. Indeed, the results of numerous studies suggest that NAD+ intermediates or small molecules that modulate sirtuin function could enhance retinal metabolism, reduce photoreceptor death, and improve vision. Although further research is necessary to translate these findings to the bedside, they have strong potential to truly transform the standard of care for patients with retinal degenerative diseases.
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Affiliation(s)
- Jonathan B Lin
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA; Neuroscience Graduate Program, Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Rajendra S Apte
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA; Neuroscience Graduate Program, Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, MO, USA; Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA; Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA.
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9
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Pyruvate kinase M2 regulates photoreceptor structure, function, and viability. Cell Death Dis 2018; 9:240. [PMID: 29445082 PMCID: PMC5833680 DOI: 10.1038/s41419-018-0296-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/18/2017] [Accepted: 12/27/2017] [Indexed: 01/30/2023]
Abstract
Pyruvate kinase M2 (PKM2) is a glycolytic enzyme that is expressed in cancer cells. Its role in tumor metabolism is not definitively established, but investigators have suggested that regulation of PKM2 activity can cause accumulation of glycolytic intermediates and increase flux through the pentose phosphate pathway. Recent evidence suggests that PKM2 also may have non-metabolic functions, including as a transcriptional co-activator in gene regulation. We reported previously that PKM2 is abundant in photoreceptor cells in mouse retinas. In the present study, we conditionally deleted PKM2 (rod-cre PKM2-KO) in rod photoreceptors and found that the absence of PKM2 causes increased expression of PKM1 in rods. Analysis of metabolic flux from U-13C glucose shows that rod-cre PKM2-KO retinas accumulate glycolytic intermediates, consistent with an overall reduction in the amount of pyruvate kinase activity. Rod-cre PKM2-KO mice also have an increased NADPH availability could favor lipid synthesis, but we found no difference in phospholipid synthesis between rod-cre PKM2 KO and PKM2-positive controls. As rod-cre PKM2-KO mice aged, we observed a significant loss of rod function, reduced thickness of the photoreceptor outer segment layer, and reduced expression of photoreceptor proteins, including PDE6β. The rod-cre PKM2-KO retinas showed greater TUNEL staining than wild-type retinas, indicating a slow retinal degeneration. In vitro analysis showed that PKM2 can regulate transcriptional activity from the PDE6β promoter in vitro. Our findings indicate that both the metabolic and transcriptional regulatory functions of PKM2 may contribute to photoreceptor structure, function, and viability.
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Jiao K, Sahaboglu A, Zrenner E, Ueffing M, Ekström PAR, Paquet-Durand F. Efficacy of PARP inhibition in Pde6a mutant mouse models for retinitis pigmentosa depends on the quality and composition of individual human mutations. Cell Death Discov 2016; 2:16040. [PMID: 27551530 PMCID: PMC4979439 DOI: 10.1038/cddiscovery.2016.40] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 04/28/2016] [Indexed: 11/09/2022] Open
Abstract
Retinitis pigmentosa (RP), an inherited blinding disease, is caused by a variety of different mutations that affect retinal photoreceptor function and survival. So far there is neither effective treatment nor cure. We have previously shown that poly(ADP-ribose)polymerase (PARP) acts as a common and critical denominator of cell death in photoreceptors, qualifying it as a potential target for future therapeutic intervention. A significant fraction of RP-causing mutations affect the genes for the rod photoreceptor phosphodiesterase 6A (PDE6A) subunit, but it is not known whether they all engage the same death pathway. Analysing three homozygous point mutations (Pde6a R562W, D670G, and V685M) and one compound heterozygous Pde6aV685M/R562W mutation in mouse models that match human RP patients, we demonstrate excessive activation of PARP, which correlated in time with the progression of photoreceptor degeneration. The causal involvement of PARP activity in the neurodegenerative process was confirmed in organotypic retinal explant cultures treated with the PARP-selective inhibitor PJ34, using different treatment time-points and durations. Remarkably, the neuroprotective efficacy of PARP inhibition correlated inversely with the strength of the genetically induced insult, with the D670G mutant showing the best treatment effects. Our results highlight PARP as a target for neuroprotective interventions in RP caused by PDE6A mutations and are a first attempt towards personalized, genotype-matched therapy development for RP. In addition, for each of the different mutant situations, our work identifies windows of opportunity for an optimal treatment regimen for further in vivo experimentation and possibly clinical studies.
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Affiliation(s)
- K Jiao
- Cell Death Mechanisms Group, Division of Experimental Ophthalmology, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Roentgenweg 11, Tuebingen 72076, Germany; Centre for Ophthalmology, The Second People's Hospital of Yunnan Province and The Fourth Affiliated Hospital of Kunming Medical University, Qingnian 176, Kunming 650021, China
| | - A Sahaboglu
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen , Tuebingen 72076, Germany
| | - E Zrenner
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen 72076, Germany; Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tuebingen, Tuebingen, Germany
| | - M Ueffing
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen , Tuebingen 72076, Germany
| | - P A R Ekström
- Division of Ophthalmology, Department of Clinical Sciences, Lund, University of Lund , Lund 22184, Sweden
| | - F Paquet-Durand
- Cell Death Mechanisms Group, Division of Experimental Ophthalmology, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen , Roentgenweg 11, Tuebingen 72076, Germany
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11
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Schnichels S, Dorfi T, Schultheiss M, Arango-Gonzalez B, Bartz-Schmidt KU, Januschowski K, Spitzer MS, Ziemssen F. Ex-vivo-examination of ultrastructural changes in organotypic retina culture using near-infrared imaging and optical coherence tomography. Exp Eye Res 2016; 147:31-36. [PMID: 27109031 DOI: 10.1016/j.exer.2016.04.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 04/08/2016] [Accepted: 04/18/2016] [Indexed: 12/27/2022]
Abstract
Optical coherence tomography (OCT) dramatically changed the way of diagnostic assessment in retinal diseases during the last years. Using this technique in-vivo in-depth analysis of the retina and its layers is possible. Since animal research is changing by intrinsic and extrinsic pressure to animal-(in-vivo)-free methods, we adapted OCT-measurements to organotypic cultures. An easy to use protocol was generated to assess standardized OCT assessments in organotypic culture. First, two custom-made devices need to be made to change any commercially available OCT for examinations in humans into a device allowing ex-vivo analyses of organotypic culture. The modification is feasible within seconds. After OCT measurement of the ex-vivo tissues, quantitative evaluation of the retinas were performed via ImageJ software. OCT pictures of ex-vivo retinas were obtained for time periods of seven days and the thickness of retinal tissue was evaluated. The reproducibility of the pictures and measurements was very high (SD < 15%). In conclusion, an easy to use protocol for the investigation of different effects on retinal cultures with commercially available OCT devices was successfully established.
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Affiliation(s)
- Sven Schnichels
- Centre of Ophthalmology, University Eye Hospital Tübingen, Schleichstr. 12/1, D-72076, Tübingen, Germany.
| | - Tanja Dorfi
- Centre of Ophthalmology, University Eye Hospital Tübingen, Schleichstr. 12/1, D-72076, Tübingen, Germany
| | - Maximilian Schultheiss
- Centre of Ophthalmology, University Eye Hospital Tübingen, Schleichstr. 12/1, D-72076, Tübingen, Germany
| | - Blanca Arango-Gonzalez
- Centre of Ophthalmology, Institute for Ophthalmic Research Tübingen, Röntgenweg 11, D-72076, Tübingen, Germany
| | - Karl-Ulrich Bartz-Schmidt
- Centre of Ophthalmology, University Eye Hospital Tübingen, Schleichstr. 12/1, D-72076, Tübingen, Germany
| | - Kai Januschowski
- Centre of Ophthalmology, University Eye Hospital Tübingen, Schleichstr. 12/1, D-72076, Tübingen, Germany; Eye Clinic Sulzbach-Saar, an der Klinik 10, 66111, Sulzbach-Saar, Germany
| | - Martin S Spitzer
- Centre of Ophthalmology, University Eye Hospital Tübingen, Schleichstr. 12/1, D-72076, Tübingen, Germany; Department of Ophthalmology, University Medical Center Hamburg-Eppendorf (UKE), Martinistraße 52, 20251, Hamburg, Germany
| | - Focke Ziemssen
- Centre of Ophthalmology, University Eye Hospital Tübingen, Schleichstr. 12/1, D-72076, Tübingen, Germany
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12
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Deletion of myosin VI causes slow retinal optic neuropathy and age-related macular degeneration (AMD)-relevant retinal phenotype. Cell Mol Life Sci 2015; 72:3953-69. [PMID: 25939269 PMCID: PMC4575690 DOI: 10.1007/s00018-015-1913-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 04/20/2015] [Accepted: 04/23/2015] [Indexed: 11/16/2022]
Abstract
The unconventional myosin VI, a member of the actin-based motor protein family of myosins, is expressed in the retina. Its deletion was previously shown to reduce amplitudes of the a- and b-waves of the electroretinogram. Analyzing wild-type and myosin VI-deficient Snell’s Waltzer mice in more detail, the expression pattern of myosin VI in retinal pigment epithelium, outer limiting membrane, and outer plexiform layer could be linked with differential progressing ocular deficits. These encompassed reduced a-waves and b-waves and disturbed oscillatory potentials in the electroretinogram, photoreceptor cell death, retinal microglia infiltration, and formation of basal laminar deposits. A phenotype comprising features of glaucoma (neurodegeneration) and age-related macular degeneration could thus be uncovered that suggests dysfunction of myosin VI and its variable cargo adaptor proteins for membrane sorting and autophagy, as possible candidate mediators for both disease forms.
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13
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Farinelli P, Perera A, Arango-Gonzalez B, Trifunovic D, Wagner M, Carell T, Biel M, Zrenner E, Michalakis S, Paquet-Durand F, Ekström PAR. DNA methylation and differential gene regulation in photoreceptor cell death. Cell Death Dis 2014; 5:e1558. [PMID: 25476906 PMCID: PMC4649831 DOI: 10.1038/cddis.2014.512] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 10/17/2014] [Accepted: 10/21/2014] [Indexed: 01/09/2023]
Abstract
Retinitis pigmentosa (RP) defines a group of inherited degenerative retinal diseases causing progressive loss of photoreceptors. To this day, RP is still untreatable and rational treatment development will require a thorough understanding of the underlying cell death mechanisms. Methylation of the DNA base cytosine by DNA methyltransferases (DNMTs) is an important epigenetic factor regulating gene expression, cell differentiation, cell death, and survival. Previous studies suggested an involvement of epigenetic mechanisms in RP, and in this study, increased cytosine methylation was detected in dying photoreceptors in the rd1, rd2, P23H, and S334ter rodent models for RP. Ultrastructural analysis of photoreceptor nuclear morphology in the rd1 mouse model for RP revealed a severely altered chromatin structure during retinal degeneration that coincided with an increased expression of the DNMT isozyme DNMT3a. To identify disease-specific differentially methylated DNA regions (DMRs) on a genomic level, we immunoprecipitated methylated DNA fragments and subsequently analyzed them with a targeted microarray. Genome-wide comparison of DMRs between rd1 and wild-type retina revealed hypermethylation of genes involved in cell death and survival as well as cell morphology and nervous system development. When correlating DMRs with gene expression data, we found that hypermethylation occurred alongside transcriptional repression. Consistently, motif analysis showed that binding sites of several important transcription factors for retinal physiology were hypermethylated in the mutant model, which also correlated with transcriptional silencing of their respective target genes. Finally, inhibition of DNMTs in rd1 organotypic retinal explants using decitabine resulted in a substantial reduction of photoreceptor cell death, suggesting inhibition of DNA methylation as a potential novel treatment in RP.
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Affiliation(s)
- P Farinelli
- 1] Division of Ophthalmology, Department of Clinical Sciences, University of Lund, BMC-B11, Lund 22184, Sweden [2] Division of Experimental Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen 72076, Germany
| | - A Perera
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich 81377, Germany
| | - B Arango-Gonzalez
- Division of Experimental Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen 72076, Germany
| | - D Trifunovic
- Division of Experimental Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen 72076, Germany
| | - M Wagner
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Ludwig-Maximilians-Universität München, Munich 81377, Germany
| | - T Carell
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Ludwig-Maximilians-Universität München, Munich 81377, Germany
| | - M Biel
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich 81377, Germany
| | - E Zrenner
- Division of Experimental Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen 72076, Germany
| | - S Michalakis
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich 81377, Germany
| | - F Paquet-Durand
- Division of Experimental Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen 72076, Germany
| | - P A R Ekström
- Division of Ophthalmology, Department of Clinical Sciences, University of Lund, BMC-B11, Lund 22184, Sweden
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