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Mbefo M, Berger A, Schouwey K, Gérard X, Kostic C, Beryozkin A, Sharon D, Dolfuss H, Munier F, Tran HV, van Lohuizen M, Beltran WA, Arsenijevic Y. Enhancer of Zeste Homolog 2 (EZH2) Contributes to Rod Photoreceptor Death Process in Several Forms of Retinal Degeneration and Its Activity Can Serve as a Biomarker for Therapy Efficacy. Int J Mol Sci 2021; 22:ijms22179331. [PMID: 34502238 PMCID: PMC8430630 DOI: 10.3390/ijms22179331] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/18/2021] [Accepted: 08/25/2021] [Indexed: 12/15/2022] Open
Abstract
Inherited retinal dystrophies (IRD) are due to various gene mutations. Each mutated gene instigates a specific cell homeostasis disruption, leading to a modification in gene expression and retinal degeneration. We previously demonstrated that the polycomb-repressive complex-1 (PRC1) markedly contributes to the cell death process. To better understand these mechanisms, we herein study the role of PRC2, specifically EZH2, which often initiates the gene inhibition by PRC1. We observed that the epigenetic mark H3K27me3 generated by EZH2 was progressively and strongly expressed in some individual photoreceptors and that the H3K27me3-positive cell number increased before cell death. H3K27me3 accumulation occurs between early (accumulation of cGMP) and late (CDK4 expression) events of retinal degeneration. EZH2 hyperactivity was observed in four recessive and two dominant mouse models of retinal degeneration, as well as two dog models and one IRD patient. Acute pharmacological EZH2 inhibition by intravitreal injection decreased the appearance of H3K27me3 marks and the number of TUNEL-positive cells revealing that EZH2 contributes to the cell death process. Finally, we observed that the absence of the H3K27me3 mark is a biomarker of gene therapy treatment efficacy in XLRPA2 dog model. PRC2 and PRC1 are therefore important actors in the degenerative process of multiple forms of IRD.
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Affiliation(s)
- Martial Mbefo
- Unit of Retinal Degeneration and Regeneration, Department of Ophthalmology, University of Lausanne, Fondation Asile des Aveugles, 1004 Lausanne, Switzerland; (M.M.); (A.B.); (K.S.); (X.G.); (C.K.)
| | - Adeline Berger
- Unit of Retinal Degeneration and Regeneration, Department of Ophthalmology, University of Lausanne, Fondation Asile des Aveugles, 1004 Lausanne, Switzerland; (M.M.); (A.B.); (K.S.); (X.G.); (C.K.)
| | - Karine Schouwey
- Unit of Retinal Degeneration and Regeneration, Department of Ophthalmology, University of Lausanne, Fondation Asile des Aveugles, 1004 Lausanne, Switzerland; (M.M.); (A.B.); (K.S.); (X.G.); (C.K.)
| | - Xavier Gérard
- Unit of Retinal Degeneration and Regeneration, Department of Ophthalmology, University of Lausanne, Fondation Asile des Aveugles, 1004 Lausanne, Switzerland; (M.M.); (A.B.); (K.S.); (X.G.); (C.K.)
| | - Corinne Kostic
- Unit of Retinal Degeneration and Regeneration, Department of Ophthalmology, University of Lausanne, Fondation Asile des Aveugles, 1004 Lausanne, Switzerland; (M.M.); (A.B.); (K.S.); (X.G.); (C.K.)
| | - Avigail Beryozkin
- Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem 91120, Israel; (A.B.); (D.S.)
| | - Dror Sharon
- Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem 91120, Israel; (A.B.); (D.S.)
| | - Hélène Dolfuss
- UMR_S 1112, Laboratoire de Génétique Médicales, University of Strasbourg, CEDEX, 67084 Strasbourg, France;
| | - Francis Munier
- Unit of Oculogenetics, Department of Ophthalmology, University of Lausanne, Fondation Asile des Aveugles, 1004 Lausanne, Switzerland; (F.M.); (H.V.T.)
| | - Hoai Viet Tran
- Unit of Oculogenetics, Department of Ophthalmology, University of Lausanne, Fondation Asile des Aveugles, 1004 Lausanne, Switzerland; (F.M.); (H.V.T.)
| | | | - William A. Beltran
- Division of Experimental Retinal Therapies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Yvan Arsenijevic
- Unit of Retinal Degeneration and Regeneration, Department of Ophthalmology, University of Lausanne, Fondation Asile des Aveugles, 1004 Lausanne, Switzerland; (M.M.); (A.B.); (K.S.); (X.G.); (C.K.)
- Correspondence:
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PEDF peptides promote photoreceptor survival in rd10 retina models. Exp Eye Res 2019; 184:24-29. [PMID: 30980815 DOI: 10.1016/j.exer.2019.04.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/19/2018] [Accepted: 04/05/2019] [Indexed: 12/20/2022]
Abstract
The purpose of the study is to evaluate the protective properties of PEDF peptide fragments on rd10 mouse models of retinal degeneration ex vivo. Human recombinant PEDF and synthetic peptides were used. Rd10 retinal explants as well as wild-type retinal explants treated with zaprinast to mimic the rd10 photoreceptor cell death were employed. PEDF protein was intravitreally administered into rd10 mice. Outer nuclear layer thickness measurements in retinal sections, TUNEL labeling in retinal explants, western blots and immunofluorescence with retinal samples were performed. PEDF protein levels in the RPE of rd10 mice decreased with age (P15 - P25). Levels of PEDF receptor PEDF-R declined in the photoreceptor inner segments from rd10 relative to wild-type mice at P25. PEDF administration increased the outer nuclear layer thickness of rd10 retinas in vivo and decreased the number of TUNEL+ nuclei of photoreceptors in rd10 retinal explant cultures, both relative to untreated controls. Peptides containing the PEDF neurotrophic region decreased the number of TUNEL+ photoreceptors in both rd10 and zaprinast-induced cell death ex vivo models, while peptides without the neurotrophic region and/or lacking affinity for PEDF-R were ineffective in protecting photoreceptors. Thus, retinal explants are a valuable system to evaluate PEDF activity. Short peptides with the photoreceptor-protective property of PEDF may prove useful for the development of therapeutic agents for photoreceptor protection in retinal degenerations.
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Sakami S, Imanishi Y, Palczewski K. Müller glia phagocytose dead photoreceptor cells in a mouse model of retinal degenerative disease. FASEB J 2018; 33:3680-3692. [PMID: 30462532 DOI: 10.1096/fj.201801662r] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Retinitis pigmentosa is a devastating, blinding disorder that affects 1 in 4000 people worldwide. During the progression of the disorder, phagocytic clearance of dead photoreceptor cell bodies has a protective role by preventing additional retinal damage from accumulation of cellular debris. However, the cells responsible for the clearance remain unidentified. Taking advantage of a mouse model of retinitis pigmentosa ( RhoP23H/P23H), we clarified the roles of Müller glia in the phagocytosis of rod photoreceptor cells. During the early stage of retinal degeneration, Müller glial cells participated in the phagocytosis of dying or dead rod photoreceptors throughout the outer nuclear layer. Nearly 50% of Müller glia engaged in phagocytosis. Among the Müller phagosomes, >90% matured into phagolysosomes. Those observations indicated that Müller glial cells are the primary contributor to phagocytosis. In contrast, macrophages migrate to the inner part of the outer nuclear layer during photoreceptor degeneration, participating in the phagocytosis of a limited population of dying or dead photoreceptor cells. In healthy retinas of wild-type mice, Müller glial cells phagocytosed cell bodies of dead rod photoreceptors albeit at a lower frequency. Taken together, the phagocytic function of Müller glia is responsible for retinal homeostasis and reorganization under normal and pathologic conditions.-Sakami, S., Imanishi, Y., Palczewski, K. Müller glia phagocytose dead photoreceptor cells in a mouse model of retinal degenerative disease.
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Affiliation(s)
- Sanae Sakami
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Yoshikazu Imanishi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
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Inamdar SM, Lankford CK, Laird JG, Novbatova G, Tatro N, Whitmore SS, Scheetz TE, Baker SA. Analysis of 14-3-3 isoforms expressed in photoreceptors. Exp Eye Res 2018; 170:108-116. [PMID: 29486162 DOI: 10.1016/j.exer.2018.02.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/02/2018] [Accepted: 02/23/2018] [Indexed: 11/18/2022]
Abstract
The 14-3-3 family of proteins has undergone considerable expansion in higher eukaryotes with humans and mice expressing seven isoforms (β, ε, η, γ, θ, ζ, and σ) from seven distinct genes (YWHAB, YWAHE, YWHAH, YWHAG, YWHAQ, YWHAZ, and SFN). Growing evidence indicates that while highly conserved, these isoforms are not entirely functionally redundant as they exhibit unique tissue expression profiles, subcellular localization, and biochemical functions. A key limitation in our understanding of 14-3-3 biology lies in our limited knowledge of cell-type specific 14-3-3 expression. Here we provide a characterization of 14-3-3 expression in whole retina and isolated rod photoreceptors using reverse-transcriptase digital droplet PCR. We find that all 14-3-3 genes with the exception of SFN are expressed in mouse retina with YWHAQ and YWHAE being the most highly expressed. Rod photoreceptors are enriched in YWHAE (14-3-3 ε). Immunohistochemistry revealed that 14-3-3 ε and 14-3-3 ζ exhibit unique distributions in photoreceptors with 14-3-3 ε restricted to the inner segment and 14-3-3 ζ localized to the outer segment. Our data demonstrates that, in the retina, 14-3-3 isoforms likely serve specific functions as they exhibit unique expression levels and cell-type specificity. As such, future investigations into 14-3-3 function in rod photoreceptors should be centered on 14-3-3 ε and 14-3-3 ζ, depending on the subcellular region of question.
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Affiliation(s)
- Shivangi M Inamdar
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Colten K Lankford
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Joseph G Laird
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Gulnara Novbatova
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Nicole Tatro
- Department of Ophthalmology & Visual Sciences and Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - S Scott Whitmore
- Department of Ophthalmology & Visual Sciences and Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Todd E Scheetz
- Department of Ophthalmology & Visual Sciences and Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Sheila A Baker
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA; Department of Ophthalmology & Visual Sciences and Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA.
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Abstract
The review intends to draw the attention of researchers working in retinal degenerations on the fact that classical apoptosis, for example, apoptosis triggering caspase activation, may not be the main pathway of cellular demise in this tissue.Former work already showed the difficulty of proving the activation of apoptosis effectors in different models of retinal degeneration. However, these results were not really considered because of the lack of an alternative explanation for cell death. Nowadays, the description of many pathways of cellular demise is filling the gap and other forms of cell death are now described in the retina.The knowledge on the molecular mechanisms of cell death is very important for the development of new therapeutic strategies, as well as for the evaluation of cell death onset in retinal degeneration.
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