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Yang P, Mustafi D, Pepple KL. Immunology of Retinitis Pigmentosa and Gene Therapy-Associated Uveitis. Cold Spring Harb Perspect Med 2024; 14:a041305. [PMID: 37037600 PMCID: PMC10562523 DOI: 10.1101/cshperspect.a041305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
The underlying immune state of inherited retinal degenerations (IRDs) and retinitis pigmentosa (RP) has been an emerging area of interest, wherein the consequences have never been greater given the widespread recognition of gene therapy-associated uveitis (GTU) in gene therapy clinical trials. Whereas some evidence suggests that the adaptive immune system may play a role, the majority of studies indicate that the innate immune system is likely the primary driver of neuroinflammation in RP. During retinal degeneration, discrete mechanisms activate resident microglia and promote infiltrating macrophages that can either be protective or detrimental to photoreceptor cell death. This persistent stimulation of innate immunity, overlaid by the introduction of viral antigens as part of gene therapy, has the potential to trigger a complex microglia/macrophage-driven proinflammatory state. A better understanding of the immune pathophysiology in IRD and GTU will be necessary to improve the success of developing novel treatments for IRDs.
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Affiliation(s)
- Paul Yang
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregan 97239, USA
| | - Debarshi Mustafi
- Department of Ophthalmology, Roger and Karalis Johnson Retina Center, University of Washington, Seattle, Washington 98109, USA
- Brotman Baty Institute for Precision Medicine, Seattle, Washington 98109, USA
- Department of Ophthalmology, Seattle Children's Hospital, Seattle, Washington 98109, USA
| | - Kathryn L Pepple
- Department of Ophthalmology, Roger and Karalis Johnson Retina Center, University of Washington, Seattle, Washington 98109, USA
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2
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Fu X, Feng S, Qin H, Yan L, Zheng C, Yao K. Microglia: The breakthrough to treat neovascularization and repair blood-retinal barrier in retinopathy. Front Mol Neurosci 2023; 16:1100254. [PMID: 36756614 PMCID: PMC9899825 DOI: 10.3389/fnmol.2023.1100254] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 01/03/2023] [Indexed: 01/24/2023] Open
Abstract
Microglia are the primary resident retinal macrophages that monitor neuronal activity in real-time and facilitate angiogenesis during retinal development. In certain retinal diseases, the activated microglia promote retinal angiogenesis in hypoxia stress through neurovascular coupling and guide neovascularization to avascular areas (e.g., the outer nuclear layer and macula lutea). Furthermore, continuously activated microglia secrete inflammatory factors and expedite the loss of the blood-retinal barrier which causes irreversible damage to the secondary death of neurons. In this review, we support microglia can be a potential cellular therapeutic target in retinopathy. We briefly describe the relevance of microglia to the retinal vasculature and blood-retinal barrier. Then we discuss the signaling pathway related to how microglia move to their destinations and regulate vascular regeneration. We summarize the properties of microglia in different retinal disease models and propose that reducing the number of pro-inflammatory microglial death and conversing microglial phenotypes from pro-inflammatory to anti-inflammatory are feasible for treating retinal neovascularization and the damaged blood-retinal barrier (BRB). Finally, we suppose that the unique properties of microglia may aid in the vascularization of retinal organoids.
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Affiliation(s)
- Xuefei Fu
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
| | - Shuyu Feng
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
| | - Huan Qin
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
| | - Lin Yan
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
| | - Caiyan Zheng
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
| | - Kai Yao
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China,College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China,Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Wuhan University of Science and Technology, Wuhan, China,*Correspondence: Kai Yao,
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3
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Kumari A, Borooah S. The Role of Microglia in Inherited Retinal Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:197-205. [PMID: 37440034 DOI: 10.1007/978-3-031-27681-1_29] [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
Inherited retinal diseases (IRDs) are a leading cause of irreversible visual loss in the developed world. The primary driver of pathology in IRDs is pathogenic genetic variant. However, there is increasing evidence, from recent studies, for a role of the immune system in disease mechanism, particularly retinal microglia. Microglia are the primary immune cells in the retina and actively contribute to disease pathogenesis when activated locally by phagocytosing photoreceptors, inducing inflammation and signaling infiltration of circulating monocytes. In this article, we discuss the evidence for the contribution of retinal microglia to IRD pathogenesis reported so far using mice model.
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Affiliation(s)
- Asha Kumari
- Jacobs Retina Center, Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA
| | - Shyamanga Borooah
- Jacobs Retina Center, Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA.
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4
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Zhou K, Han J, Wang Y, Xu Y, Zhang Y, Zhu C. The therapeutic potential of bone marrow-derived macrophages in neurological diseases. CNS Neurosci Ther 2022; 28:1942-1952. [PMID: 36066198 PMCID: PMC9627381 DOI: 10.1111/cns.13964] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/19/2022] [Accepted: 08/22/2022] [Indexed: 02/06/2023] Open
Abstract
Circulating monocytes are precursors of both tissue macrophages and dendritic cells, and they can infiltrate the central nervous system (CNS) where they transform into bone marrow-derived macrophages (BMDMs). BMDMs play essential roles in various CNS diseases, thus modulating BMDMs might be a way to treat these disorders because there are currently no efficient therapeutic methods available for most of these neurological diseases. Moreover, BMDMs can serve as promising gene delivery vehicles following bone marrow transplantation for otherwise incurable genetic CNS diseases. Understanding the distinct roles that BMDMs play in CNS diseases and their potential as gene delivery vehicles may provide new insights and opportunities for using BMDMs as therapeutic targets or delivery vehicles. This review attempts to comprehensively summarize the neurological diseases that might be treated by modulating BMDMs or by delivering gene therapies via BMDMs after bone marrow transplantation.
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Affiliation(s)
- Kai Zhou
- Henan Neurodevelopment Engineering Research Center for ChildrenChildren's Hospital Affiliated to Zhengzhou UniversityZhengzhouChina
| | - Jinming Han
- Department of Neurology, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Yafeng Wang
- Henan Neurodevelopment Engineering Research Center for ChildrenChildren's Hospital Affiliated to Zhengzhou UniversityZhengzhouChina,Department of Hematology and OncologyChildren's Hospital Affiliated to Zhengzhou University, Henan, Children's Hospital, Zhengzhou Children's HospitalZhengzhouChina
| | - Yiran Xu
- Henan Key Laboratory of Child Brain Injury and Henan Pediatric Clinical Research CenterThe Third Affiliated Hospital and Institute of Neuroscience, Zhengzhou UniversityZhengzhouChina
| | - Yaodong Zhang
- Henan Neurodevelopment Engineering Research Center for ChildrenChildren's Hospital Affiliated to Zhengzhou UniversityZhengzhouChina
| | - Changlian Zhu
- Henan Key Laboratory of Child Brain Injury and Henan Pediatric Clinical Research CenterThe Third Affiliated Hospital and Institute of Neuroscience, Zhengzhou UniversityZhengzhouChina,Centre for Brain Repair and RehabilitationInstitute of Neuroscience and Physiology, Sahlgrenska Academy, University of GothenburgGothenburgSweden
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5
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Kalogerou M, Ioannou S, Kolovos P, Prokopiou E, Potamiti L, Kyriacou K, Panagiotidis M, Ioannou M, Fella E, Worth EP, Georgiou T. Omega-3 fatty acids promote neuroprotection, decreased apoptosis and reduced glial cell activation in the retina of a mouse model of OPA1-related autosomal dominant optic atrophy. Exp Eye Res 2022; 215:108901. [DOI: 10.1016/j.exer.2021.108901] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 01/10/2023]
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6
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Brunet AA, Harvey AR, Carvalho LS. Primary and Secondary Cone Cell Death Mechanisms in Inherited Retinal Diseases and Potential Treatment Options. Int J Mol Sci 2022; 23:ijms23020726. [PMID: 35054919 PMCID: PMC8775779 DOI: 10.3390/ijms23020726] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/05/2022] [Accepted: 01/05/2022] [Indexed: 12/13/2022] Open
Abstract
Inherited retinal diseases (IRDs) are a leading cause of blindness. To date, 260 disease-causing genes have been identified, but there is currently a lack of available and effective treatment options. Cone photoreceptors are responsible for daylight vision but are highly susceptible to disease progression, the loss of cone-mediated vision having the highest impact on the quality of life of IRD patients. Cone degeneration can occur either directly via mutations in cone-specific genes (primary cone death), or indirectly via the primary degeneration of rods followed by subsequent degeneration of cones (secondary cone death). How cones degenerate as a result of pathological mutations remains unclear, hindering the development of effective therapies for IRDs. This review aims to highlight similarities and differences between primary and secondary cone cell death in inherited retinal diseases in order to better define cone death mechanisms and further identify potential treatment options.
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Affiliation(s)
- Alicia A. Brunet
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia;
- Lions Eye Institute Ltd., 2 Verdun St, Nedlands, WA 6009, Australia
- Correspondence: ; Tel.: +61-423-359-714
| | - Alan R. Harvey
- School of Human Sciences, The University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia;
- Perron Institute for Neurological and Translational Science, 8 Verdun St, Nedlands, WA 6009, Australia
| | - Livia S. Carvalho
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia;
- Lions Eye Institute Ltd., 2 Verdun St, Nedlands, WA 6009, Australia
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7
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Lin B, Youdim MBH. The protective, rescue and therapeutic potential of multi-target iron-chelators for retinitis pigmentosa. Free Radic Biol Med 2021; 174:1-11. [PMID: 34324978 DOI: 10.1016/j.freeradbiomed.2021.07.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 07/15/2021] [Accepted: 07/23/2021] [Indexed: 12/11/2022]
Abstract
Retinitis pigmentosa (RP) is a group of inherited diseases in which mutations result in the initial loss of night vision, followed by complete blindness. There is currently no effective therapeutic option for RP patients. Given the extremely heterogeneous nature of RP, any causative gene-specific therapy would be practical in a small fraction of patients with RP. Non-gene-specific therapeutics that is applicable to the majority of RP patients regardless of causative mutations may have an enormous impact on RP treatment. Several theories including apoptosis, oxidative stress and neuroinflammation have been proposed as possible underlying mechanisms for photoreceptor death in RP. We have designed and synthesized a series of iron-chelating compounds that possess diverse pharmacological properties and can act in a non-gene-specific manner on multiple pathological features ascribed to Alzheimer's disease, Parkinson's disease and RP. In this review, we discuss the multiple effects of several brain-permeable multi target iron-chelating compounds on photoreceptor degeneration in a mouse model of human RP. Specifically, we focus on the anti-apototic, neuroprotective and neurorescue effects of the compound VK28, M30 and VAR10303 on the histologic and functional preservation of photoreceptors in a mouse model of RP. We consider such drugs as potential therapeutic agents for RP patients.
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Affiliation(s)
- Bin Lin
- School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
| | - Moussa B H Youdim
- Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
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8
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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: 18] [Impact Index Per Article: 6.0] [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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9
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Wang Y, Tang Z, Gu P. Stem/progenitor cell-based transplantation for retinal degeneration: a review of clinical trials. Cell Death Dis 2020; 11:793. [PMID: 32968042 PMCID: PMC7511341 DOI: 10.1038/s41419-020-02955-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/21/2020] [Accepted: 08/27/2020] [Indexed: 12/14/2022]
Abstract
Retinal degeneration (RD) is one of the dominant causes of irreversible vision impairment and blindness worldwide. However, the current effective therapeutics for RD in the ophthalmologic clinic are unclear and controversial. In recent years, extensively investigated stem/progenitor cells—including retinal progenitor cells (RPCs), embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs) and mesenchymal stromal cells (MSCs)—with proliferation and multidirectional differentiation potential have presented opportunities to revolutionise the ultimate clinical management of RD. Herein, we provide a comprehensive overview on the progression of clinical trials for RD treatment using four types of stem/progenitor cell-based transplantation to replace degenerative retinal cells and/or to supplement trophic factors from the aspects of safety, effectiveness and their respective advantages and disadvantages. In addition, we also discuss the emerging role of stem cells in the secretion of multifunctional nanoscale exosomes by which stem cells could be further exploited as a potential RD therapy. This review will facilitate the understanding of scientists and clinicians of the enormous promise of stem/progenitor cell-based transplantation for RD treatment, and provide incentive for superior employment of such strategies that may be suitable for treatment of other diseases, such as stroke and ischaemia–reperfusion injury.
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Affiliation(s)
- Yiqi Wang
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, 200011, P.R. China
| | - Zhimin Tang
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, 200011, P.R. China
| | - Ping Gu
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, 200011, P.R. China.
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10
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Olivares-González L, Velasco S, Millán JM, Rodrigo R. Intravitreal administration of adalimumab delays retinal degeneration in rd10 mice. FASEB J 2020; 34:13839-13861. [PMID: 32816354 DOI: 10.1096/fj.202000044rr] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 08/03/2020] [Accepted: 08/07/2020] [Indexed: 12/13/2022]
Abstract
Retinitis pigmentosa (RP) is a group of inherited retinal dystrophies characterized by the progressive and irreversible loss of vision. We previously found that intraperitoneal administration of Adalimumab, a monoclonal anti-TNFα antibody, slowed down retinal degeneration in the murine model of RP, the rd10 mice. The aims of this study were to improve its neuroprotective effect and to deepen understanding of the molecular mechanisms involved in this effect. We analyzed (i) the in vitro effect of Adalimumab on the TNFα-mediated cell death in retinal cells; (ii) the effect of a single intravitreal injection of Adalimumab on retinal degeneration in rd10 mice at postnatal day (P) 23. In vitro studies showed that TNFα induced caspase and poly ADP ribose polymerase (PARP) activation, downregulation of (kinase receptor-interacting protein 1) RIPK1 and upregulation of RIPK3 in retinal cells. Adalimumab reduced cell death probably through the inhibition of caspase 3 activation. In vivo studies suggested that PARP and NLRP3 inflammasome are mainly activated and to a lesser extent caspase-dependent mechanisms in rd10 retinas at P23. Necroptosis seems to be inhibited by the downregulation of RIPK1. Adalimumab prevented from retinal degeneration without affecting caspase -dependent mechanisms but decreasing PARP activation, microglia activation as well as NLRP3 inflammasome.
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Affiliation(s)
- Lorena Olivares-González
- Pathophysiology and Therapies for Vision Disorders, Principe Felipe Research Center, Valencia, Spain
| | - Sheyla Velasco
- Pathophysiology and Therapies for Vision Disorders, Principe Felipe Research Center, Valencia, Spain
| | - José María Millán
- Rare Diseases Networking Biomedical Research Centre (CIBERER), Madrid, Spain.,Joint Unit on Rare Diseases CIPF-La Fe, Valencia, Spain.,Molecular, Cellular and Genomic Biomedicine, Health Research Institute La Fe, Valencia, Spain
| | - Regina Rodrigo
- Pathophysiology and Therapies for Vision Disorders, Principe Felipe Research Center, Valencia, Spain.,Rare Diseases Networking Biomedical Research Centre (CIBERER), Madrid, Spain.,Joint Unit on Rare Diseases CIPF-La Fe, Valencia, Spain
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11
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Lew DS, Mazzoni F, Finnemann SC. Microglia Inhibition Delays Retinal Degeneration Due to MerTK Phagocytosis Receptor Deficiency. Front Immunol 2020; 11:1463. [PMID: 32765507 PMCID: PMC7381113 DOI: 10.3389/fimmu.2020.01463] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 06/05/2020] [Indexed: 12/19/2022] Open
Abstract
Retinitis Pigmentosa (RP) is a group of inherited retinal diseases characterized by progressive loss of rod followed by cone photoreceptors. An especially early onset form of RP with blindness in teenage years is caused by mutations in mertk, the gene encoding the clearance phagocytosis receptor Mer tyrosine kinase (MerTK). The cause for blindness in mutant MerTK-associated RP (mutMerTK-RP) is the failure of retinal pigment epithelial cells in diurnal phagocytosis of spent photoreceptor outer segment debris. However, the early onset and very fast progression of degeneration in mutMerTK-RP remains unexplained. Here, we explored the role of microglia in the Royal College of Surgeons (RCS) rat model of mutMerTK-RP. We found elevated levels of inflammatory cytokines and CD68 microglia activation marker, and more ionized calcium-binding adapter molecule 1 (Iba-1) positive microglia in RCS retina when compared to wild-type retina as early as postnatal day 14 (P14). Strikingly, renewal of photoreceptor outer segments in P14 wild-type rat retina is still immature with low levels of RPE phagocytosis implying that at this early age lack of this process in RCS rats is unlikely to distress photoreceptors. Although the total number of Iba-1 positive retinal microglia remains constant from P14 to P30, we observed increasing numbers of microglia in the outer retina from P20 implying migration to the outer retina before onset of photoreceptor cell death at ~P25. Iba-1 and CD68 levels also increase in the retina during this time period suggesting microglia activation. To determine whether microglia affect the degenerative process, we suppressed retinal microglia in vivo using tamoxifen or a combination of tamoxifen and liposomal clodronate. Treatments partly prevented elevation of Iba-1 and CD68 and relocalization of microglia. Moreover, treatments led to partial but significant retention of photoreceptor viability and photoreceptor function. We conclude that loss of the phagocytosis receptor MerTK causes microglia activation and relocalization in the retina before lack of RPE phagocytosis causes overt retinal degeneration, and that microglia activities accelerate loss of photoreceptors in mutMerTK-RP. These results suggest that therapies targeting microglia may delay onset and slow the progression of this blinding disease.
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Affiliation(s)
- Deborah S Lew
- Department of Biological Sciences, Center for Cancer, Genetic Diseases and Gene Regulation, Fordham University, Bronx, NY, United States
| | - Francesca Mazzoni
- Department of Biological Sciences, Center for Cancer, Genetic Diseases and Gene Regulation, Fordham University, Bronx, NY, United States
| | - Silvia C Finnemann
- Department of Biological Sciences, Center for Cancer, Genetic Diseases and Gene Regulation, Fordham University, Bronx, NY, United States
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12
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Wlodarek L, Cao F, Alibhai FJ, Fekete A, Noyan N, Tobin SW, Marvasti TB, Wu J, Li SH, Weisel RD, Wang LY, Jia Z, Li RK. Rectification of radiotherapy-induced cognitive impairments in aged mice by reconstituted Sca-1 + stem cells from young donors. J Neuroinflammation 2020; 17:51. [PMID: 32028989 PMCID: PMC7006105 DOI: 10.1186/s12974-019-1681-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 12/17/2019] [Indexed: 01/03/2023] Open
Abstract
Background Radiotherapy is widely used and effective for treating brain tumours, but inevitably impairs cognition as it arrests cellular processes important for learning and memory. This is particularly evident in the aged brain with limited regenerative capacity, where radiation produces irreparable neuronal damage and activation of neighbouring microglia. The latter is responsible for increased neuronal death and contributes to cognitive decline after treatment. To date, there are few effective means to prevent cognitive deficits after radiotherapy. Methods Here we implanted hematopoietic stem cells (HSCs) from young or old (2- or 18-month-old, respectively) donor mice expressing green fluorescent protein (GFP) into old recipients and assessed cognitive abilities 3 months post-reconstitution. Results Regardless of donor age, GFP+ cells homed to the brain of old recipients and expressed the macrophage/microglial marker, Iba1. However, only young cells attenuated deficits in novel object recognition and spatial memory and learning in old mice post-irradiation. Mechanistically, old recipients that received young HSCs, but not old, displayed significantly greater dendritic spine density and long-term potentiation (LTP) in CA1 neurons of the hippocampus. Lastly, we found that GFP+/Iba1+ cells from young and old donors were differentially polarized to an anti- and pro-inflammatory phenotype and produced neuroprotective factors and reactive nitrogen species in vivo, respectively. Conclusion Our results suggest aged peripherally derived microglia-like cells may exacerbate cognitive impairments after radiotherapy, whereas young microglia-like cells are polarized to a reparative phenotype in the irradiated brain, particularly in neural circuits associated with rewards, learning, and memory. These findings present a proof-of-principle for effectively reinstating central cognitive function of irradiated brains with peripheral stem cells from young donor bone marrow. Electronic supplementary material The online version of this article (10.1186/s12974-019-1681-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lukasz Wlodarek
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Feng Cao
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Program in Neurosciences & Mental Health, SickKids Research Institute, Floor 5, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada
| | - Faisal J Alibhai
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada
| | - Adam Fekete
- Program in Neurosciences & Mental Health, SickKids Research Institute, Floor 5, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada
| | - Nima Noyan
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada
| | - Stephanie W Tobin
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada
| | - Tina B Marvasti
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada.,Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Jun Wu
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada
| | - Shu-Hong Li
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada
| | - Richard D Weisel
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada.,Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Department of Surgery, Division of Cardiac Surgery, University of Toronto, Toronto, ON, Canada
| | - Lu-Yang Wang
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada. .,Program in Neurosciences & Mental Health, SickKids Research Institute, Floor 5, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada.
| | - Zhengping Jia
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada. .,Program in Neurosciences & Mental Health, SickKids Research Institute, Floor 5, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada.
| | - Ren-Ke Li
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada. .,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada. .,Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, ON, Canada. .,Department of Surgery, Division of Cardiac Surgery, University of Toronto, Toronto, ON, Canada.
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Sundar JC, Munezero D, Bryan-Haring C, Saravanan T, Jacques A, Ramamurthy V. Rhodopsin signaling mediates light-induced photoreceptor cell death in rd10 mice through a transducin-independent mechanism. Hum Mol Genet 2020; 29:394-406. [PMID: 31925423 PMCID: PMC7015845 DOI: 10.1093/hmg/ddz299] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 11/22/2019] [Accepted: 12/02/2019] [Indexed: 01/08/2023] Open
Abstract
Retinitis pigmentosa (RP) is a debilitating blinding disease affecting over 1.5 million people worldwide, but the mechanisms underlying this disease are not well understood. One of the common models used to study RP is the retinal degeneration-10 (rd10) mouse, which has a mutation in Phosphodiesterase-6b (Pde6b) that causes a phenotype mimicking the human disease. In rd10 mice, photoreceptor cell death occurs with exposure to normal light conditions, but as demonstrated in this study, rearing these mice in dark preserves their retinal function. We found that inactivating rhodopsin signaling protected photoreceptors from degeneration suggesting that the pathway activated by this G-protein-coupled receptor is causing light-induced photoreceptor cell death in rd10 mice. However, inhibition of transducin signaling did not prevent the loss of photoreceptors in rd10 mice reared under normal light conditions implying that the degeneration caused by rhodopsin signaling is not mediated through its canonical G-protein transducin. Inexplicably, loss of transducin in rd10 mice also led to photoreceptor cell death in darkness. Furthermore, we found that the rd10 mutation in Pde6b led to a reduction in the assembled PDE6αβγ2 complex, which was corroborated by our data showing mislocalization of the γ subunit. Based on our findings and previous studies, we propose a model where light activates a non-canonical pathway mediated by rhodopsin but independent of transducin that sensitizes cyclic nucleotide gated channels to cGMP and causes photoreceptor cell death. These results generate exciting possibilities for treatment of RP patients without affecting their vision or the canonical phototransduction cascade.
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Affiliation(s)
- Jesse C Sundar
- Departments of Biochemistry, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26505, USA
| | - Daniella Munezero
- Departments of Ophthalmology and Visual Sciences, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26505, USA
| | - Caitlyn Bryan-Haring
- Departments of Biochemistry, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26505, USA
| | - Thamaraiselvi Saravanan
- Departments of Ophthalmology and Visual Sciences, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26505, USA
| | - Angelica Jacques
- Departments of Ophthalmology and Visual Sciences, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26505, USA
| | - Visvanathan Ramamurthy
- Departments of Biochemistry, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26505, USA
- Departments of Ophthalmology and Visual Sciences, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26505, USA
- Departments of Neuroscience, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26505, USA
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Microglial Cell Dysfunction in CRB1-Associated Retinopathies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1185:159-163. [PMID: 31884605 DOI: 10.1007/978-3-030-27378-1_26] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Inherited retinal diseases encompass a large group of clinically and genetically heterogeneous diseases estimated to affect two million people worldwide. Among these people, approximately 80,000 are or will become blind in their first decades of life due to mutations in both alleles of the Crumbs homologue-1 (CRB1) gene. Microglia are the resident immune surveyor cells in the retina, and their roles have been heavily studied in several retinal diseases, including retinitis pigmentosa (RP), age-related macular degeneration, and diabetic retinopathy. However, very little is known about the role of microglia in CRB1-associated retinopathies. Thus, we here summarize the main findings described in the literature concerning inflammation and the role of microglia in CRB1-patients and CRB1-rodent models.
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Kim TH, Son T, Lu Y, Alam M, Yao X. Comparative Optical Coherence Tomography Angiography of Wild-Type and rd10 Mouse Retinas. Transl Vis Sci Technol 2018; 7:42. [PMID: 30619662 PMCID: PMC6314228 DOI: 10.1167/tvst.7.6.42] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 11/02/2018] [Indexed: 12/11/2022] Open
Abstract
Purpose To conduct longitudinal optical coherence tomography angiography (OCTA) to characterize dynamic changes of trilaminar vascular plexuses in wild-type (WT) and retinal degeneration 10 (rd10) mouse retinas. Methods Longitudinal in vivo OCT/OCTA measurements of WT and rd10 mouse retinas were conducted at postnatal day 14 (P14), P17, P21, P24, and P28. OCT images were used to quantify retinal thickness changes, while OCTA images were used to investigate vascular dynamics within the trilaminar vascular plexuses, that is, superficial vascular plexus (SVP), intermediate capillary plexus (ICP), and deep capillary plexus (DCP). Blood vessel densities of all three plexus layers were quantitatively evaluated separately. The caliber of first-order blood vessel branches in the SVP layer was also measured. Results Vascular densities in all three plexuses continuously decreased with aging in both WT and rd10. However, abnormal density reduction in rd10 occurred at P17 in both ICP (P < 0.001) and DCP (P < 0.001). While the ICP of rd10 showed density recovery at P24, the DCP of rd10 showed significantly low density. Remarkable vascular narrowing in rd10 was also observed in the SVP, especially at P28. Conclusions The most severe vascular impairment happened in the DCP, while the ICP showed the transient recovery of vascular density after the onset of retinal degeneration. The SVP was most resistant to the retinal degeneration, but the first-order blood vessel branches within the SVP showed progressive narrowing. Translational Relevance Better understanding of the vascular changes correlated with retinal development, and retinal degeneration can provide insights in advanced development of treatment protocols of retinal degenerative diseases.
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Affiliation(s)
- Tae-Hoon Kim
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Taeyoon Son
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Yiming Lu
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Minhaj Alam
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA.,Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
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Abstract
Microglia, the primary resident immune cell type, constitute a key population of glia in the retina. Recent evidence indicates that microglia play significant functional roles in the retina at different life stages. During development, retinal microglia regulate neuronal survival by exerting trophic influences and influencing programmed cell death. During adulthood, ramified microglia in the plexiform layers interact closely with synapses to maintain synaptic structure and function that underlie the retina's electrophysiological response to light. Under pathological conditions, retinal microglia participate in potentiating neurodegeneration in diseases such as glaucoma, retinitis pigmentosa, and age-related neurodegeneration by producing proinflammatory neurotoxic cytokines and removing living neurons via phagocytosis. Modulation of pathogenic microglial activation states and effector mechanisms has been linked to neuroprotection in animal models of retinal diseases. These findings have led to the design of early proof-of-concept clinical trials with microglial modulation as a therapeutic strategy.
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Affiliation(s)
- Sean M. Silverman
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;,
| | - Wai T. Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;,
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Dutta R, Trapp BD. Much, if not all, of the cortical damage in MS can be attributed to the microglial cell - No. Mult Scler 2018; 24:897-899. [PMID: 29754529 DOI: 10.1177/1352458517743094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Ranjan Dutta
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Bruce D Trapp
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
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Murakami Y, Ikeda Y, Nakatake S, Fujiwara K, Tachibana T, Yoshida N, Notomi S, Hisatomi T, Yoshida S, Ishibashi T, Sonoda KH. C-Reactive protein and progression of vision loss in retinitis pigmentosa. Acta Ophthalmol 2018. [PMID: 28636270 DOI: 10.1111/aos.13502] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PURPOSE Chronic inflammation is involved in retinitis pigmentosa (RP). We demonstrated previously that intraocular inflammatory levels, as measured by slit-lamp ophthalmoscopy or laser flare photometry, are inversely correlated with central visual function in patients with RP. Here, we investigated the relationship between serum high-sensitivity C-reactive protein (hs-CRP) and visual parameters in RP. METHODS We studied 58 consecutive typical patients with RP <40 years old and 29 age- and gender-matched controls. High-sensitivity C-reactive protein (hs-CRP) was detected by immunoturbidimetry. The relationships between hs-CRP and visual parameters including best-corrected visual acuity (BCVA), mean deviation (MD) of static perimetry tests (Humphrey Field Analyzer, the central 10-2 programme) and VA changes over the prior 5 years and MD changes over the prior 3 years were analysed in the patients with RP. RESULTS The serum hs-CRP levels of the patients with RP were significantly higher than those of the controls (0.06 ± 0.08 versus 0.03 ± 0.04 mg/dl, p = 0.0119). In the patients with RP, there was no correlation of hs-CRP with cross-sectionally assessed VA or MD, but the baseline hs-CRP was significantly correlated with the MD deterioration (r = -0.4073, p = 0.0314). CONCLUSION The average serum hs-CRP was significantly increased in the patients with RP, and higher hs-CRP was associated with faster deterioration of central visual function. These results suggest that the systemic inflammatory profile is altered and may be associated with disease progression in RP.
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Affiliation(s)
- Yusuke Murakami
- Department of Ophthalmology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
| | - Yasuhiro Ikeda
- Department of Ophthalmology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
| | - Shunji Nakatake
- Department of Ophthalmology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
| | - Kohta Fujiwara
- Department of Ophthalmology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
- Department of Ophthalmology; Akita University Graduate School of Medicine; Akita Japan
| | - Takashi Tachibana
- Department of Ophthalmology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
| | - Noriko Yoshida
- Department of Ophthalmology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
| | - Shoji Notomi
- Department of Ophthalmology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
| | - Toshio Hisatomi
- Department of Ophthalmology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
| | - Shigeo Yoshida
- Department of Ophthalmology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
| | - Tatsuro Ishibashi
- Department of Ophthalmology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
| | - Koh-Hei Sonoda
- Department of Ophthalmology; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
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Kung F, Wang W, Tran TS, Townes-Anderson E. Sema3A Reduces Sprouting of Adult Rod Photoreceptors In Vitro. Invest Ophthalmol Vis Sci 2017; 58:4318–4331. [PMID: 28806446 PMCID: PMC5555408 DOI: 10.1167/iovs.16-21075] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Purpose Rod photoreceptor terminals respond to retinal injury with retraction and sprouting. Since the guidance cue Semaphorin3A (Sema3A) is observed in the retina after injury, we asked whether Sema3A contributes to structural plasticity in rod photoreceptors. Methods We used Western blots and alkaline phosphatase (AP)-tagged neuropilin-1 (NPN-1) to detect the expression of Sema3A in an organotypic model of porcine retinal detachment. We then examined Sema3A binding to cultured salamander rod photoreceptors using AP-tagged Sema3A. For functional analysis, we used a microspritzer to apply a gradient of Sema3A-Fc to isolated salamander rod photoreceptors over 24 hours. Results Sema3A protein was biochemically detected in porcine retinal explants in the retina 7, 24, and 72 hours after detachment. In sections, NPN-1 receptor was bound to the inner and outer retina. For isolated rod photoreceptors, Sema3A localized to synaptic terminals and to neuritic processes after 1 week in vitro. In microspritzed rod photoreceptors, process initiation occurred away from high concentrations of Sema3A. Sema3A significantly decreased the number of processes formed by rod photoreceptors although the average length of processes was not affected. The cellular orientation of rod photoreceptors relative to the microspritzer also significantly changed over time; this effect was reduced with the Sema3A inhibitor, xanthofulvin. Conclusion Sema3A is expressed in the retina after detachment, binds to rod photoreceptors, affects cell orientation, and reduces photoreceptor process initiation in vitro. Our results suggest that Sema3A contributes to axonal retraction in retinal injury, whereas rod neuritic sprouting and regenerative synaptogenesis may require a reduction in semaphorin signaling.
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Affiliation(s)
- Frank Kung
- Joint Program in Biomedical Engineering, Rutgers University, Graduate School of Biomedical Sciences, New Jersey Institute of Technology, Newark, United States
| | - Weiwei Wang
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University, New Jersey Medical School, Newark, New Jersey, United States
| | - Tracy S Tran
- Department of Biological Sciences, Rutgers University, Newark College of Arts and Sciences, Newark, New Jersey, United States
| | - Ellen Townes-Anderson
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University, New Jersey Medical School, Newark, New Jersey, United States
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Tang Z, Zhang Y, Wang Y, Zhang D, Shen B, Luo M, Gu P. Progress of stem/progenitor cell-based therapy for retinal degeneration. J Transl Med 2017; 15:99. [PMID: 28486987 PMCID: PMC5424366 DOI: 10.1186/s12967-017-1183-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 04/14/2017] [Indexed: 01/14/2023] Open
Abstract
Retinal degeneration (RD), such as age-related macular degeneration (AMD) and retinitis pigmentosa, is one of the leading causes of blindness. Presently, no satisfactory therapeutic options are available for these diseases principally because the retina and retinal pigmented epithelium (RPE) do not regenerate, although wet AMD can be prevented from further progression by anti-vascular endothelial growth factor therapy. Nevertheless, stem/progenitor cell approaches exhibit enormous potential for RD treatment using strategies mainly aimed at the rescue and replacement of photoreceptors and RPE. The sources of stem/progenitor cells are classified into two broad categories in this review, which are (1) ocular-derived progenitor cells, such as retinal progenitor cells, and (2) non-ocular-derived stem cells, including embryonic stem cells, induced pluripotent stem cells, and mesenchymal stromal cells. Here, we discuss in detail the progress in the study of four predominant stem/progenitor cell types used in animal models of RD. A short overview of clinical trials involving the stem/progenitor cells is also presented. Currently, stem/progenitor cell therapies for RD still have some drawbacks such as inhibited proliferation and/or differentiation in vitro (with the exception of the RPE) and limited long-term survival and function of grafts in vivo. Despite these challenges, stem/progenitor cells represent the most promising strategy for RD treatment in the near future.
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Affiliation(s)
- Zhimin Tang
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People's Republic of China
| | - Yi Zhang
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People's Republic of China
| | - Yuyao Wang
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People's Republic of China
| | - Dandan Zhang
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People's Republic of China
| | - Bingqiao Shen
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People's Republic of China
| | - Min Luo
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People's Republic of China.
| | - Ping Gu
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People's Republic of China.
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Koso H, Tsuhako A, Lai CY, Baba Y, Otsu M, Ueno K, Nagasaki M, Suzuki Y, Watanabe S. Conditional rod photoreceptor ablation reveals Sall1 as a microglial marker and regulator of microglial morphology in the retina. Glia 2016; 64:2005-24. [PMID: 27459098 DOI: 10.1002/glia.23038] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 06/10/2016] [Accepted: 07/07/2016] [Indexed: 12/18/2022]
Abstract
Neurodegeneration has been shown to induce microglial activation and the infiltration of monocyte-derived macrophages into the CNS, resulting in the coexistence of these two populations within the same lesion, though their distinct features remain elusive. To investigate the impact of rod photoreceptor degeneration on microglial activation, we generated a toxin-mediated genetic model of rod degeneration. Rod injury induced microglial proliferation and migration toward the photoreceptors. Bone marrow transplantation revealed the invasion of monocyte-derived macrophages into the retina, with microglia and the infiltrating macrophages showing distinct distribution patterns in the retina. By comparing the gene expression profiles of the activated microglia and infiltrating macrophages, we identified microglia-specific genes, including Ak1, Ctsf, Sall1, Phlda3, and Spns2. An analysis of Sall1gfp knock-in mice showed GFP expression in the microglia of developing and mature healthy retinas. DTA injury induced the expansion of Sall1gfp(+) microglia, whereas Ly6C(+) monocyte-derived macrophages were mostly Sall1gfp(-) , supporting the idea that Sall1 is exclusively expressed in microglia within the retinal phagocyte pool. We evaluated the contribution of microglia to the phagocyte pool in rd1 mutant retinas and found that Sall1gfp(+) microglia constituted the majority of phagocytes. A Sall1 deficiency did not affect microglial colonization of the retina and the cortex, but it did change their morphology from a ramified to a more amoeboid appearance. The morphological defects observed in Sall1-deficient microglia were not rescued by the presence of wild-type non-microglial cells, suggesting that Sall1 functions cell-autonomously in microglia. Taken together, our data indicate that Sall1 regulates microglial morphology during development. GLIA 2016;64:2005-2024.
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Affiliation(s)
- Hideto Koso
- Division of Molecular and Developmental Biology, Institute of Medical Science, the University of Tokyo, Tokyo, Japan
| | - Asano Tsuhako
- Division of Molecular and Developmental Biology, Institute of Medical Science, the University of Tokyo, Tokyo, Japan
| | - Chen-Yi Lai
- Division of Stem Cell Processing and Stem Cell Bank, Institute of Medical Science, the University of Tokyo, Tokyo, Japan
| | - Yukihiro Baba
- Division of Molecular and Developmental Biology, Institute of Medical Science, the University of Tokyo, Tokyo, Japan
| | - Makoto Otsu
- Division of Stem Cell Processing and Stem Cell Bank, Institute of Medical Science, the University of Tokyo, Tokyo, Japan
| | - Kazuko Ueno
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Masao Nagasaki
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Yutaka Suzuki
- Department of Bioinformatics and Systems Biology, Graduate School of Frontier Sciences, the University of Tokyo, Kashiwa, Japan
| | - Sumiko Watanabe
- Division of Molecular and Developmental Biology, Institute of Medical Science, the University of Tokyo, Tokyo, Japan.
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Friend or Foe? Resident Microglia vs Bone Marrow-Derived Microglia and Their Roles in the Retinal Degeneration. Mol Neurobiol 2016; 54:4094-4112. [PMID: 27318678 DOI: 10.1007/s12035-016-9960-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 06/06/2016] [Indexed: 01/10/2023]
Abstract
Microglia are immune cells in the central nervous system (CNS) that originate from the yolk sac in an embryo. The renewal of the microglia pool in the adult eye consists of two components. In addition to the self-proliferation of resident cells, microglia in the CNS also derive from the bone marrow (BM). BM-derived cells pass through the blood-brain barrier (BBB) or blood-retina barrier (BRB) and differentiate into microglia under specific conditions which involves a complex mechanism. Recent studies have widely investigated the role of resident microglia and BM-derived microglia in the retinal degenerative disease. Both two cell types play dual roles and share many similar functions. However, resident microglia tend to polarize to the M1 phenotype which is pro-inflammatory and neurotoxic, whereas BM-derived microglia mainly polarize to the neuroprotective M2 phenotype in retinal degeneration. The molecular mechanism that underlines the invasion of peripheral cells has led to extensive discussions. In addition to the BBB and BRB disruption, many signaling pathways are involved in this process. Based on these studies, we discuss the roles of these two types of microglia in retinal degeneration disease and the potential clinical application of BM-derived microglia, which may benefit future therapies.
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Microglial Activation Promotes Cell Survival in Organotypic Cultures of Postnatal Mouse Retinal Explants. PLoS One 2015; 10:e0135238. [PMID: 26252475 PMCID: PMC4529135 DOI: 10.1371/journal.pone.0135238] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 07/20/2015] [Indexed: 02/03/2023] Open
Abstract
The role of microglia during neurodegeneration remains controversial. We investigated whether microglial cells have a neurotoxic or neuroprotective function in the retina. Retinal explants from 10-day-old mice were treated in vitro with minocycline to inhibit microglial activation, with LPS to increase microglial activation, or with liposomes loaded with clodronate (Lip-Clo) to deplete microglial cells. Flow cytometry was used to assess the viability of retinal cells in the explants and the TUNEL method to show the distribution of dead cells. The immunophenotypic and morphological features of microglia and their distribution were analyzed with flow cytometry and immunocytochemistry. Treatment of retinal explants with minocycline reduced microglial activation and simultaneously significantly decreased cell viability and increased the presence of TUNEL-labeled cell profiles. This treatment also prevented the migration of microglial cells towards the outer nuclear layer, where cell death was most abundant. The LPS treatment increased microglial activation but had no effect on cell viability or microglial distribution. Finally, partial microglial removal with Lip-Clo diminished the cell viability in the retinal explants, showing a similar effect to that of minocycline. Hence, cell viability is diminished in retinal explants cultured in vitro when microglial cells are removed or their activation is inhibited, indicating a neurotrophic role for microglia in this system.
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Relationship between aqueous flare and visual function in retinitis pigmentosa. Am J Ophthalmol 2015; 159:958-63.e1. [PMID: 25677184 DOI: 10.1016/j.ajo.2015.02.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Revised: 02/01/2015] [Accepted: 02/02/2015] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate the correlation between aqueous flare values and central visual function in patients with retinitis pigmentosa (RP). DESIGN Retrospective, observational case series. METHODS We retrospectively studied 160 patients diagnosed with typical RP and 59 control subjects. Aqueous flare values were measured by laser flare cell meter. The relationships between aqueous flare and best-corrected visual acuity (VA) and mean deviation (MD) of static perimetry tests were analyzed in RP patients. RESULTS The aqueous flare values were significantly higher in the RP patients compared to the control subjects (10.6 ± 7.9 vs 5.0 ± 2.1 photon counts per millisecond [pc/ms], P < .0001). In the RP patients, the aqueous flare values were negatively correlated with VA (r = 0.359, P < .0001) and MD (r = -0.330, P < .0001). Age-subgroup analysis showed a significant correlation between aqueous flare and VA in the RP patients' 40s, 50s, and 60s and between aqueous flare and MD in the 30s, 40s, 50s, and 60s. The RP patients with MD values ≥-15 decibels (dB) showed significantly higher levels of aqueous flare than those with MD values <-15 dB (12.0 ± 6.2 vs 8.7 ± 5.8, P = .0001). CONCLUSIONS Aqueous flare is increased in RP patients and negatively correlates with central visual function. These results suggest a close relationship between inflammation and central vision loss in RP.
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Neuroprotective and antiapoptotic activity of lineage-negative bone marrow cells after intravitreal injection in a mouse model of acute retinal injury. Stem Cells Int 2015; 2015:620364. [PMID: 25810725 PMCID: PMC4354968 DOI: 10.1155/2015/620364] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 01/02/2015] [Indexed: 12/21/2022] Open
Abstract
We investigated effects of bone marrow-derived, lineage-negative cell (Lin(-)BMC) transplantation in acute retinal injury. Lin(-)BMCs were intravitreally injected into murine eyes at 24 h after NaIO3-induced injury. Morphology, function, and expression of apoptosis-related genes, including brain-derived neurotrophic factor (BDNF) and its receptor, were assessed in retinas at 7 days, 28 days, and 3 months after transplantation. Moreover, global gene expression at day 7 was analyzed by RNA arrays. We observed that Lin(-)BMCs integrated into outer retinal layers improving morphological retinal structure and induced molecular changes such as downregulation of proapoptotic caspase-3 gene, a decrease in BAX/BCL-2 gene ratio, and significant elevation of BDNF expression. Furthermore, transplanted Lin(-)BMCs differentiated locally into cells with a macrophage-like phenotype. Finally, Lin(-)BMCs treatment was associated with generation of two distinct transcriptomic patterns. The first relates to downregulated genes associated with regulation of neuron cell death and apoptosis, response to oxidative stress/hypoxia and external stimuli, and negative regulation of cell proliferation. The second relates to upregulated genes associated with neurological system processes and sensory perception. Collectively, our data demonstrate that transplanted Lin(-)BMCs exert neuroprotective function against acute retinal injury and this effect may be associated with their antiapoptotic properties and ability to express neurotrophic factors.
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Martínez-Fernández de la Cámara C, Olivares-González L, Hervás D, Salom D, Millán JM, Rodrigo R. Infliximab reduces Zaprinast-induced retinal degeneration in cultures of porcine retina. J Neuroinflammation 2014; 11:172. [PMID: 25301432 PMCID: PMC4200228 DOI: 10.1186/s12974-014-0172-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 09/25/2014] [Indexed: 01/24/2023] Open
Abstract
Background cGMP-degrading phosphodiesterase 6 (PDE6) mutations cause around 4 to 5% of retinitis pigmentosa (RP), a rare form of retinal dystrophy. Growing evidence suggests that inflammation is involved in the progression of RP. The aims of this study were to corroborate the presence of high TNFα concentration in the eyes of RP patients and to evaluate whether the blockade of TNFα with Infliximab, a monoclonal anti-TNFα antibody, prevented retinal degeneration induced by PDE6 inhibition in cultures of porcine retina. Methods Aqueous humor from 30 patients with RP and 13 healthy controls were used to quantify the inflammatory mediators IL-6, TNFα, IL-1β, IL-10 by a multiplex enzyme-linked immunosorbent assay (ELISA) system. Retinal explants from pig were exposed to Zaprinast, a PDE6 inhibitor, for 24 hours in the absence or the presence of Infliximab. Cell death was evaluated by TUNEL assay. The number and distribution of caspase-3 positive cells, indirect poly(ADP)ribose polymerase (PARP) activation and glial fibrillary acidic protein (GFAP) content were visualized by immunolabeling. Antioxidant total capacity, nitrites and thiobarbituric acid reactive substances (TBARS) formation were determined to evaluate antioxidant-oxidant status. Results IL-6 and TNFα concentrations were higher in the aqueous humor of RP patients than in controls. Infliximab prevented retinal degeneration, as judging by the reduced presence of TUNEL-positive cells, the reduction of caspase-3 activation and also reduction of glial activation, in an ex vivo model of porcine retina. Additionally, Infliximab partially reduced oxidative stress in retinal explants exposed to Zaprinast. Conclusions Inflammatory mediators IL-6 and TNFα were elevated in the aqueous humor of RP patients corroborating previous studies suggesting sustained chronic inflammation. Our study suggests that TNFα is playing an important role in cell death in an ex vivo model of retinal degeneration by activating different cell pathways at different cell layers of the retina that should be further studied. Electronic supplementary material The online version of this article (doi:10.1186/s12974-014-0172-9) contains supplementary material, which is available to authorized users.
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Suppression of microglial activation is neuroprotective in a mouse model of human retinitis pigmentosa. J Neurosci 2014; 34:8139-50. [PMID: 24920619 DOI: 10.1523/jneurosci.5200-13.2014] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Retinitis pigmentosa (RP) is a photoreceptor-degenerative disease caused by various mutations and is characterized by death of rod photoreceptor cell followed by gradual death of cone photoreceptors. The molecular mechanisms that lead to rod and cone death are not yet fully understood. Neuroinflammation contributes to the progression of many chronic neurodegenerative disorders. However, it remains to be determined how microglia contribute to photoreceptor disruption in RP. In this study, we explored the role of microglia as a contributor to photoreceptor degeneration in the rd10 mouse model of RP. First, we demonstrated that microglia activation was an early alteration in RP retinas. Inhibition of microglia activation by minocycline reduced photoreceptor apoptosis and significantly improved retinal structure and function and visual behavior in rd10 mice. Second, we identified that minocycline exerted its neuroprotective effects through both anti-inflammatory and anti-apoptotic mechanisms. Third, we found that Cx3cr1 deficiency dysregulated microglia activation and subsequently resulted in increased photoreceptor vulnerability in rd10 mice, suggesting that the Cx3cl1/Cx3cr1 signaling pathway might protect against microglia neurotoxicity. We concluded that suppression of neuroinflammatory responses could be a potential treatment strategy aimed at improving photoreceptor survival in human RP.
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Fukuda S, Nagano M, Yamashita T, Kimura K, Tsuboi I, Salazar G, Ueno S, Kondo M, Kunath T, Oshika T, Ohneda O. Functional endothelial progenitor cells selectively recruit neurovascular protective monocyte-derived F4/80(+) /Ly6c(+) macrophages in a mouse model of retinal degeneration. Stem Cells 2014; 31:2149-61. [PMID: 23843337 DOI: 10.1002/stem.1469] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 06/08/2013] [Accepted: 06/11/2013] [Indexed: 01/23/2023]
Abstract
Retinitis pigmentosa is a group of inherited eye disorders that result in profound vision loss with characteristic retinal neuronal degeneration and vasculature attenuation. In a mouse model of retinitis pigmentosa, endothelial progenitor cells (EPC) from bone marrow rescued the vasculature and photoreceptors. However, the mechanisms and cell types underlying these protective effects were uncertain. We divided EPC, which contribute to angiogenesis, into two subpopulations based on their aldehyde dehydrogenase (ALDH) activity and observed that EPC with low ALDH activity (Alde-Low) had greater neuroprotection and vasoprotection capabilities after injection into the eyes of an rd1 mouse model of retinitis pigmentosa compared with EPC with high ALDH activity (Alde-High). Of note, Alde-Low EPC selectively recruited F4/80(+) /Ly6c(+) monocyte-derived macrophages from bone marrow into retina through CCL2 secretion. In addition, the mRNA levels of CCR2, the neurotrophic factors TGF-β1 and IGF-1, and the anti-inflammatory mediator interleukin-10 were higher in migrated F4/80(+) /Ly6c(+) monocyte-derived macrophages as compared with F4/80(+) /Ly6c(-) resident retinal microglial cells. These results suggest a novel therapeutic approach using EPC to recruit neuroprotective macrophages that delay the progression of neural degenerative disease.
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Affiliation(s)
- Shinichi Fukuda
- Department of Regenerative Medicine and Stem Cell Biology, Graduate School of Comprehensive Human Science; Department of Ophthalmology, Graduate School of Comprehensive Human Science, University of Tsukuba, Tsukuba, Japan
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Ezquer F, Ezquer M, Arango-Rodriguez M, Conget P. Could donor multipotent mesenchymal stromal cells prevent or delay the onset of diabetic retinopathy? Acta Ophthalmol 2014; 92:e86-95. [PMID: 23773776 DOI: 10.1111/aos.12113] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Diabetes mellitus is a complex metabolic disease that has become a global epidemic with more than 285 million cases worldwide. Major medical advances over the past decades have substantially improved its management, extending patients' survival. The latter is accompanied by an increased risk of developing chronic macro- and microvascular complications. Amongst them, diabetic retinopathy (DR) is the most common and frightening. Furthermore, during the past two decades, it has become the leading cause of visual loss. Irrespective of the type of diabetes, DR follows a well-known clinical and temporal course characterized by pericytes and neuronal cell loss, formation of acellular-occluded capillaries, occasional microaneurysms, increased leucostasis and thickening of the vascular basement membrane. These alterations progressively affect the integrity of retinal microvessels, leading to the breakdown of the blood-retinal barrier, widespread haemorrhage and neovascularization. Finally, tractional retinal detachment occurs leading to blindness. Nowadays, there is growing evidence that local inflammation and oxidative stress play pivotal roles in the pathogenesis of DR. Both processes have been associated with pericytes and neuronal degeneration observed early during DR progression. They may also be linked to sustained retinal vasculature damage that results in abnormal neovascularization. Currently, DR therapeutic options depend on highly invasive surgical procedures performed only at advanced stages of the disease, and which have proved to be ineffective to restore visual acuity. Therefore, the availability of less invasive and more effective strategies aimed to prevent or delay the onset of DR is highly desirable. Multipotent mesenchymal stromal cells, also referred to as mesenchymal stem cells (MSCs), are promising healing agents as they contribute to tissue regeneration by pleiotropic mechanisms, with no evidence of significant adverse events. Here, we revise the pathophysiology of DR to identify therapeutic targets for donor MSCs. Also, we discuss whether an MSC-based therapy could prevent or delay the onset of DR.
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Affiliation(s)
- Fernando Ezquer
- Institute of Science, Faculty of Medicine Clinica Alemana Universidad del Desarrollo, Lo Barnechea, Santiago, Chile
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Genini S, Beltran WA, Stein VM, Aguirre GD. Isolation and ex vivo characterization of the immunophenotype and function of microglia/macrophage populations in normal dog retina. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:339-45. [PMID: 24664716 DOI: 10.1007/978-1-4614-3209-8_43] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Microglia are the primary resident immune cells of the retina and are involved in the pathogenesis of various retinal diseases. In this study, we optimized experimental conditions to isolate microglia from canine retinas and characterized ex vivo their immunophenotype and function using flow cytometry (FACS). The most suitable protocol included a mechanical dissociation of the retina and an enzymatic digestion using DNAse and collagenase. Extraction was carried out by density gradient centrifugation, and retinal microglia accumulated on distinct interfaces of 1.072 and 1.088 g/mL of a Percoll gradient. Immunophenotypical characterization was performed with monoclonal antibodies CD11b, CD11c, CD18, CD45, CD44, B7-1 (CD80), B7-2 (CD86), CD1c, ICAM-1 (CD54), CD14, MHCI, MHCII, CD68, CD3, CD4, CD8α, and CD21. The most prevalent microglia population in the normal canine retina is CD11b(high)CD45(low). Functionally, retinal microglia exhibited phagocytosis and reactive oxygen species (ROS) generation activities. To conclude, ex vivo examinations of retinal microglia are feasible and possibly reflect the in vivo conditions, avoiding artifacts observed in tissue culture. The established method will be relevant to examine microglia from diseased canine retinas in order to elucidate their roles in degenerative processes.
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Affiliation(s)
- Sem Genini
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, 3900 Delancey Street, 19104, Philadelphia, PA, USA,
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Han J, Dinculescu A, Dai X, Du W, Smith WC, Pang J. Review: the history and role of naturally occurring mouse models with Pde6b mutations. Mol Vis 2013; 19:2579-89. [PMID: 24367157 PMCID: PMC3869645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 12/18/2013] [Indexed: 11/08/2022] Open
Abstract
Mouse models are useful tools for developing potential therapies for human inherited retinal diseases, such as retinitis pigmentosa (RP), since more strains are being identified with the same mutant genes and phenotypes as humans with corresponding retinal degenerative diseases. Mutations in the beta subunit of the human rod phosphodiesterase (PDE6B) gene are a common cause of autosomal recessive RP (arRP). This article focuses on two well-established naturally occurring mouse models of arRP caused by spontaneous mutations in Pde6b, their discovery, phenotype, mechanism of degeneration, strengths and limitations, and therapeutic approaches to restore vision and delay disease progression. Viral vector, especially adeno-associated viral vector (AAV) -mediated gene replacement therapy, pharmacological treatment, cell-based therapy and other approaches that extend the therapeutic window of treatment, is a potentially promising strategy for improving photoreceptor function and significantly slowing the process of retinal degeneration.
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Affiliation(s)
- Juanjuan Han
- Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Astra Dinculescu
- Department of Ophthalmology, University of Florida, Gainesville, FL
| | - Xufeng Dai
- Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Wei Du
- Department of Ophthalmology, University of Florida, Gainesville, FL
| | - W. Clay Smith
- Department of Ophthalmology, University of Florida, Gainesville, FL
| | - Jijing Pang
- Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China,Department of Ophthalmology, University of Florida, Gainesville, FL
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Sennlaub F, Auvynet C, Calippe B, Lavalette S, Poupel L, Hu SJ, Dominguez E, Camelo S, Levy O, Guyon E, Saederup N, Charo IF, Rooijen NV, Nandrot E, Bourges JL, Behar-Cohen F, Sahel JA, Guillonneau X, Raoul W, Combadiere C. CCR2(+) monocytes infiltrate atrophic lesions in age-related macular disease and mediate photoreceptor degeneration in experimental subretinal inflammation in Cx3cr1 deficient mice. EMBO Mol Med 2013; 5:1775-93. [PMID: 24142887 PMCID: PMC3840491 DOI: 10.1002/emmm.201302692] [Citation(s) in RCA: 214] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 08/28/2013] [Accepted: 08/30/2013] [Indexed: 12/11/2022] Open
Abstract
Atrophic age-related macular degeneration (AMD) is associated with the subretinal accumulation of mononuclear phagocytes (MPs). Their role in promoting or inhibiting retinal degeneration is unknown. We here show that atrophic AMD is associated with increased intraocular CCL2 levels and subretinal CCR2+ inflammatory monocyte infiltration in patients. Using age- and light-induced subretinal inflammation and photoreceptor degeneration in Cx3cr1 knockout mice, we show that subretinal Cx3cr1 deficient MPs overexpress CCL2 and that both the genetic deletion of CCL2 or CCR2 and the pharmacological inhibition of CCR2 prevent inflammatory monocyte recruitment, MP accumulation and photoreceptor degeneration in vivo. Our study shows that contrary to CCR2 and CCL2, CX3CR1 is constitutively expressed in the retina where it represses the expression of CCL2 and the recruitment of neurotoxic inflammatory CCR2+ monocytes. CCL2/CCR2 inhibition might represent a powerful tool for controlling inflammation and neurodegeneration in AMD.
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Affiliation(s)
- Florian Sennlaub
- Inserm, U 968, Paris, France; UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France; Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 503, Paris, France; Hôtel Dieu, Service d'Ophtalmologie, Centre de Recherche Ophtalmologique, Paris, France
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Nussenblatt RB, Liu B, Wei L, Sen HN. The immunological basis of degenerative diseases of the eye. Int Rev Immunol 2013; 32:97-112. [PMID: 23360161 DOI: 10.3109/08830185.2012.740536] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
It has become clear that disorders that were once considered "degenerative" have complex mechanisms, with many having been shown to have immune mediation as part of the disease process. These include arteriosclerotic heart disease and Alzheimer's disease. Indeed, several ocular disorders that once fell into the "degenerative" category meet this criterion as well. Immune mediation has been shown to be a part of many of the most common ocular disorders, and not just that of uveitis, or ocular inflammatory disease.
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Affiliation(s)
- Robert B Nussenblatt
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD 20814, USA.
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Wnt/β-catenin signaling triggers neuron reprogramming and regeneration in the mouse retina. Cell Rep 2013; 4:271-86. [PMID: 23850287 DOI: 10.1016/j.celrep.2013.06.015] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 03/01/2013] [Accepted: 06/11/2013] [Indexed: 12/11/2022] Open
Abstract
Cell-fusion-mediated somatic-cell reprogramming can be induced in culture; however, whether this process occurs in mammalian tissues remains enigmatic. Here, we show that upon activation of Wnt/β-catenin signaling, mouse retinal neurons can be transiently reprogrammed in vivo back to a precursor stage. This occurs after their spontaneous fusion with transplanted hematopoietic stem and progenitor cells (HSPCs). Moreover, we demonstrate that retinal damage is essential for cell-hybrid formation in vivo. Newly formed hybrids can proliferate, commit to differentiation toward a neuroectodermal lineage, and finally develop into terminally differentiated neurons. This results in partial regeneration of the damaged retinal tissue, with functional rescue. Following retinal damage and induction of Wnt/β-catenin signaling, cell-fusion-mediated reprogramming also occurs after endogenous recruitment of bone-marrow-derived cells in the eyes. Our data demonstrate that in vivo reprogramming of terminally differentiated retinal neurons after their fusion with HSPCs is a potential mechanism for tissue regeneration.
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Wang NK, Lai CC, Liu CH, Yeh LK, Chou CL, Kong J, Nagasaki T, Tsang SH, Chien CL. Origin of fundus hyperautofluorescent spots and their role in retinal degeneration in a mouse model of Goldmann-Favre syndrome. Dis Model Mech 2013; 6:1113-22. [PMID: 23828046 PMCID: PMC3759331 DOI: 10.1242/dmm.012112] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Goldmann-Favre syndrome, also known as enhanced S-cone syndrome, is an inherited retinal degeneration disease in which a gain of photoreceptor cell types results in retinal dysplasia and degeneration. Although microglia have been implicated in the pathogenesis of many neurodegenerative diseases, the fundamental role of these cells in this disease is unknown. In the current study, sequential analyses suggest that microglia are recruited and appear after outer nuclear layer folding. By crossing rd7 mice (a model for hereditary retinal degeneration owing to Nr2e3 mutation) with mice carrying the macrophage Fas-induced apoptosis (Mafia) transgene, we generated double-mutant mice and studied the role of the resident retinal microglia. Microglial cells in these double-mutant mice express enhanced green fluorescent protein (EGFP) and a suicide gene that can trigger Fas-mediated apoptosis via systemic treatment with AP20187 (FK506 dimerizer). We demonstrated that more than 80% of the EGFP+ cells in retinas from rd7/rd7;Tg/Tg mice express Iba-1 (a microglial marker), and resident microglia are still present in the retina because AP20187 does not cross the blood-brain barrier. Hence, only circulating bone marrow (BM)-derived microglia are depleted. Depletion of circulating BM-derived microglia accelerates retinal degeneration in rd7 mice. An increased number of autofluorescent (AF) spots is a consequence of resident microglia proliferation, which in turn establishes an inflammatory cytokine milieu via the upregulation of IL-1β, IL-6 and TNFα expression. This inflammation is likely to accelerate retinal degeneration. This study not only identifies inflammation as a crucial step in the pathogenesis of retinal degeneration, but also highlights the involvement of specific cytokine genes that could serve as future treatment targets in retinal degenerations.
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Affiliation(s)
- Nan-Kai Wang
- Department of Anatomy and Cell Biology, National Taiwan University, Taipei 100, Taiwan
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Huang L, Xu W, Xu G. Transplantation of CX3CL1-expressing mesenchymal stem cells provides neuroprotective and immunomodulatory effects in a rat model of retinal degeneration. Ocul Immunol Inflamm 2013; 21:276-85. [PMID: 23718544 DOI: 10.3109/09273948.2013.791925] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE To investigate the neuroprotective and immunomodulatory effects of mesenchymal stem cells (MSCs) engineered to secrete CX3CL1 on the light-injured retinal structure and function. METHODS Normal MSCs and CX3CL1-expressing MSCs (CX3CL1-MSCs) were transplanted into the subretinal space of light-injured rats. By ERG and TUNEL methods, their rescue effect of the host retina was compared with untreated light-injured and vehicle-injected rats. Activated microglia in the retina were stained by ED-1 antibody, and Western blot was performed to quantify cytokines secreted by the retina post-transplantation. RESULTS ERG analysis showed better function in CX3CL1-MSC-injected group than other groups at 21 days after transplantation (p < 0.05). CX3CL1-MSCs inhibited apoptosis of the retinal cells and microglial activation. Neurotrophic factors expression in host retina that received CX3CL1-MSCs was stronger than in the retina that received normal MSCs. Conversely, the expression of proinflammatory factors was downregulated. CONCLUSIONS CX3CL1-MSCs subretinal transplantation may enhance protective effect against light-induced retinal degeneration.
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Affiliation(s)
- Libin Huang
- Department of Ophthalmology, First Affiliated Hospital of Fujian Medical University, Fujian Institute of Ophthalmology, Fuzhou, China
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Avraham-Lubin BCR, Goldenberg-Cohen N, Sadikov T, Askenasy N. VEGF induces neuroglial differentiation in bone marrow-derived stem cells and promotes microglia conversion following mobilization with GM-CSF. Stem Cell Rev Rep 2013; 8:1199-210. [PMID: 22810360 DOI: 10.1007/s12015-012-9396-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE Evaluation of potential tropic effects of vascular endothelial growth factor (VEGF) on the incorporation and differentiation of bone-marrow-derived stem cells (BMSCs) in a murine model of anterior ischemic optic neuropathy (AION). METHODS In the first approach, small-sized subset of BMCs were isolated from GFP donors mice by counterflow centrifugal elutriation and depleted of hematopoietic lineages (Fr25lin(-)). These cells were injected into a peripheral vein (1 × 10(6) in 0.2 ml) or inoculated intravitreally (2 × 10(5)) to syngeneic mice, with or without intravitreal injection of 5 μg/2μL VEGF, simultaneously with AION induction. In a second approach, hematopoietic cells were substituted by myelablative transplant of syngeseic GFP + bone marrow cells. After 3 months, progenitors were mobilized with granulocyte-macrophage colony-stimulating factor (GM-CSF) followed by VEGF inoculation into the vitreous body and AION induction . Engraftment and phenotype were examined by immunohistochemistry and FISH at 4 and 24 weeks post-transplantation, and VEGF receptors were determined by real time PCR. RESULTS VEGF had no quantitative effect on incorporation of elutriated cells in the injured retina, yet it induced early expression of neuroal markers in cells incorporated in the RGC layer and promoted durable gliosis, most prominent perivascular astrocytes. These effects were mediated by VEGF-R1/Flt-1, which is constitutively expresses in the elutriated fraction of stem cells. Mobilization with GM-CSF limited the differentiation of bone marrow progenitors to microglia, which was also fostered by VEGF. CONCLUSIONS VEGF signaling mediated by Flt-1 induces early neural and sustained astrocytic differentiation of stem cells elutriated from adult bone-marrow, with significant contribution to stabilization retinal architecture following ischemic injury.
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Affiliation(s)
- Bat-Chen R Avraham-Lubin
- The Krieger Eye Research Laboratory, Felsenstein Medical Research Center, Tel Aviv University, Petach Tikva, Israel
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Kohno H, Chen Y, Kevany BM, Pearlman E, Miyagi M, Maeda T, Palczewski K, Maeda A. Photoreceptor proteins initiate microglial activation via Toll-like receptor 4 in retinal degeneration mediated by all-trans-retinal. J Biol Chem 2013; 288:15326-41. [PMID: 23572532 DOI: 10.1074/jbc.m112.448712] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Although several genetic and biochemical factors are associated with the pathogenesis of retinal degeneration, it has yet to be determined how these different impairments can cause similar degenerative phenotypes. Here, we report microglial/macrophage activation in both a Stargardt disease and age-related macular degeneration mouse model caused by delayed clearance of all-trans-retinal from the retina, and in a retinitis pigmentosa mouse model with impaired retinal pigment epithelium (RPE) phagocytosis. Mouse microglia displayed RPE cytotoxicity and increased production of inflammatory chemokines/cytokines, Ccl2, Il1b, and Tnf, after coincubation with ligands that activate innate immunity. Notably, phagocytosis of photoreceptor proteins increased the activation of microglia/macrophages and RPE cells isolated from model mice as well as wild-type mice. The mRNA levels of Tlr2 and Tlr4, which can recognize proteins as their ligands, were elevated in mice with retinal degeneration. Bone marrow-derived macrophages from Tlr4-deficient mice did not increase Ccl2 after coincubation with photoreceptor proteins. Tlr4(-/-)Abca4(-/-)Rdh8(-/-) mice displayed milder retinal degenerative phenotypes than Abca4(-/-)Rdh8(-/-) mice. Additionally, inactivation of microglia/macrophages by pharmacological approaches attenuated mouse retinal degeneration. This study demonstrates an important contribution of TLR4-mediated microglial activation by endogenous photoreceptor proteins in retinal inflammation that aggravates retinal cell death. This pathway is likely to represent an underlying common pathology in degenerative retinal disorders.
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Affiliation(s)
- Hideo Kohno
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106-7286, USA
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The eye as a model of ageing in translational research--molecular, epigenetic and clinical aspects. Ageing Res Rev 2013; 12:490-508. [PMID: 23274270 DOI: 10.1016/j.arr.2012.11.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 11/16/2012] [Accepted: 11/19/2012] [Indexed: 12/13/2022]
Abstract
The eye and visual system are valuable in many areas of translational research such as stem cell therapy, transplantation research and gene therapy. Changes in many ocular tissues can be measured directly, easily and objectively in vivo (e.g. lens transparency; retinal blood vessel calibre; corneal endothelial cell counts) and so the eye may also be a uniquely useful site as a model of ageing. This review details cellular, molecular and epigenetic mechanisms related to ageing within the eye, and describes ocular parameters that can be directly measured clinically and which might be of value in ageing research as the translational "window to the rest of the body". The eye is likely to provide a valuable model for validating biomarkers of ageing at molecular, epigenetic, cellular and clinical levels. A research agenda to definitively establish the relationship between biomarkers of ageing and ocular parameters is proposed.
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Guo C, Otani A, Oishi A, Kojima H, Makiyama Y, Nakagawa S, Yoshimura N. Knockout of ccr2 alleviates photoreceptor cell death in a model of retinitis pigmentosa. Exp Eye Res 2012; 104:39-47. [PMID: 23022404 DOI: 10.1016/j.exer.2012.08.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 07/23/2012] [Accepted: 08/31/2012] [Indexed: 01/23/2023]
Abstract
Neuroinflammation involving CC chemokines such as monocyte chemoattractant protein-1 (MCP-1) has been demonstrated in the pathological process of retinitis pigmentosa (RP), an inherited degenerative retinal disease. However, the mechanism of MCP-1 and its receptor CCR2 involvement in the disease remains unclear. To investigate the role of MCP1/CCR2 in RP pathogenesis, ccr2 mutant RP mice (ccr2(-/-) rd10) were created and analyzed. The expression of MCP-1, RANTES, stromal cell-derived factor (SDF-1), and tumor necrosis factor-α (TNF-α) in the retinas of wild-type, rd10, and ccr2(-/-) rd10 mice was analyzed using quantitative RT-PCR. Photoreceptor apoptosis (TUNEL staining) and the number of microglia (positive for the F4/80 antibody) in the retina were examined. Retinal function was assessed using electroretinograms, and the structure of the whole retina was analyzed from images obtained using optical coherence tomography (OCT) and by histological examination. The expression levels of MCP-1, RANTES, and SDF-1 increased with time in the rd10 mice but not in the wild-type mice. Rearing the mice in the dark prevented degeneration and resulted in thicker photoreceptor layers at each time point. In those mice, the peaks of chemokine expression shifted to a later time with degeneration, suggesting that the expression of these chemokines was induced during the progression of degeneration. Although the difference was not so obvious, the retina in the ccr2(-/-) rd10 mice was consistently and significantly thicker than that in the rd10 (ccr2(+/+) rd10) mice at all time points. Rhodopsin gene expression was also higher in the ccr2(-/-) rd10 mice than in rd10 (ccr2(+/+) rd10) mice, suggesting photoreceptor survival in the former. Retinal function was also better preserved in the ccr2(-/-) rd10 mice than in the rd10 mice. The number of microglia in the retinas of the ccr2(-/-) rd10 mice was significantly lower than that in the retinas of the rd10 mice. Interestingly, the MCP-1 induction that was observed in the retinas of the rd10 mice was diminished in the retinas of the ccr2(-/-) rd10 mice. Our results suggest that the MCP-1/CCR2 system plays a role in retinal degeneration in rd mouse retinas. Retinal MCP-1 expression in the rd mouse retina may be partially controlled by ccr2-positive circulating cells.
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Affiliation(s)
- Congrong Guo
- Department of Ophthalmology, Kyoto University Graduate School of Medicine, 54-Kawaharacho, Shogoin, Kyoto 606-8507, Japan
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Mowat FM, Gonzalez F, Luhmann UFO, Lange CA, Duran Y, Smith AJ, Maxwell PH, Ali RR, Bainbridge JWB. Endogenous erythropoietin protects neuroretinal function in ischemic retinopathy. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:1726-39. [PMID: 22342523 DOI: 10.1016/j.ajpath.2011.12.033] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 11/14/2011] [Accepted: 12/08/2011] [Indexed: 01/12/2023]
Abstract
Because retinal ischemia is a common cause of vision loss, we sought to determine the effects of ischemia on neuroretinal function and survival in murine oxygen-induced retinopathy (OIR) and to define the role of endogenous erythropoietin (EPO) in this model. OIR is a reproducible model of ischemia-induced retinal neovascularization; it is used commonly to develop antiangiogenic strategies. We investigated the effects of ischemia in murine OIR on retinal function and neurodegeneration by electroretinography and detailed morphology. OIR was associated with significant neuroretinal dysfunction, with reduced photopic and scotopic ERG responses and reduced b-wave/a-wave ratios consistent with specific inner-retinal dysfunction. OIR resulted in significantly increased apoptosis and atrophy of the inner retina in areas of ischemia. EPO deficiency in heterozygous Epo-Tag transgenic mice was associated with more profound retinal dysfunction after OIR, indicated by a significantly greater suppression of ERG amplitudes, but had no measurable effect on the extent of retinal ischemia, preretinal neovascularization, or neuroretinal degeneration in OIR. Systemic administration of recombinant EPO protected EPO-deficient mice against this additional suppression, but EPO supplementation in wild-type animals with OIR did not rescue neuroretinal dysfunction or degeneration. Murine OIR offers a valuable model of ischemic neuroretinal dysfunction and degeneration in which to investigate adaptive tissue responses and evaluate novel therapeutic approaches. Endogenous EPO can protect neuroretinal function in ischemic retinopathy.
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Affiliation(s)
- Freya M Mowat
- Department of Genetics, University College London Institute of Ophthalmology, London, United Kingdom
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43
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Genini S, Beltran WA, Aguirre GD. Development and validation of a canine-specific profiling array to examine expression of pro-apoptotic and pro-survival genes in retinal degenerative diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 723:353-63. [PMID: 22183353 PMCID: PMC3959790 DOI: 10.1007/978-1-4614-0631-0_46] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We developed an expression profiling array to examine pro-apoptotic and pro-survival genes in dog retinal degeneration models. Gene specific canine TaqMan assays were developed and included in a custom real-time quantitative reverse transcription-PCR (qRT-PCR) array. Of the 96 selected genes, 93 belonged to known relevant pro-apoptotic and pro-survival pathways, and/or were positive controls expressed in retina, while 3 were housekeeping genes. Ingenuity Pathway Analysis (IPA) showed that the selected genes belonged to expected biological functions (cell death, cell-mediated immune response, cellular development, function, and maintenance) and pathways (death receptor signaling, apoptosis, TNFR1 signaling, and induction of apoptosis by HIV1). Validation of the profiling array was performed with RNA extracted from cultured MDCK cells in the presence or absence of treatment with 10 μM staurosporin for 5 or 10 hrs. The vast majority of the genes showed positive amplifications, and a number of them also had fold change (FC) differences > +/−3 between control and staurosporin-treated cells. To conclude, we established a profiling array that will be used to identify differentially expressed genes associated with photoreceptor death or survival in canine models of retinal degenerative diseases with mutations in genes that cause human inherited blindness with comparable phenotypes.
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Affiliation(s)
- Sem Genini
- Section of Ophthalmology, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - William A. Beltran
- Section of Ophthalmology, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gustavo D. Aguirre
- Section of Ophthalmology, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Li H, Yan Z, Cao H, Wang Y. Effective mobilisation of bone marrow-derived cells through proteolytic activity: a new treatment strategy for age-related macular degeneration. Med Hypotheses 2011; 78:286-90. [PMID: 22129485 DOI: 10.1016/j.mehy.2011.11.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 10/16/2011] [Accepted: 11/08/2011] [Indexed: 12/12/2022]
Abstract
Selective targeting of bone marrow-derived cells (BMCs) has been heralded as a promising avenue for age-related macular degeneration (AMD) therapeutics. Many researchers have demonstrated that the function of circulating BMCs is related to disease severity in patients with AMD. Transplanted BMCs are able to transdifferentiate into retina-specific cells to replace those lost due to damage or degeneration in the pathologic process of experimental models of AMD, which may provide beneficial effects in patients with AMD. However, a major barrier to transferring the use of BMCs into clinical practice is the limited quantity of BMCs in the peripheral circulation. Technology has not yet reached a stage where ex vivo-expanded BMCs can be routinely used for cell therapy. A feasible strategy to circumvent this issue of BMC scarcity is to increase the mobilisation of autologous BMCs from the patient's bone marrow into the blood circulation. Extensive studies have demonstrated that the SDF-1/CXCR4 axis is a key regulator for BMC mobilisation. Moreover, abrogation of the SDF-1/CXCR4 axis by proteolytic modification can efficiently increase BMC mobilisation. We speculate that BMC mobilisation by proteolytic enzymes may supply a sufficient amount of autologous cells to repair and regenerate injured and degenerated the retinal pigment epithelium (RPE), photoreceptors, or other retina-specific cells, which could prevent AMD progression. If the BMC mobilisation strategy is used to treat AMD, it may overcome the existing problems of transferring BMC-based therapy into the clinic and become a particularly feasible therapeutic approach for AMD.
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Affiliation(s)
- Hong Li
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, PR China
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Otani A, Kojima H, Guo C, Oishi A, Yoshimura N. Low-dose-rate, low-dose irradiation delays neurodegeneration in a model of retinitis pigmentosa. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 180:328-36. [PMID: 22074737 DOI: 10.1016/j.ajpath.2011.09.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 09/07/2011] [Accepted: 09/14/2011] [Indexed: 12/17/2022]
Abstract
The existence of radiation hormesis is controversial. Several stimulatory effects of low-dose (LD) radiation have been reported to date; however, the effects on neural tissue or neurodegeneration remain unknown. Here, we show that LD radiation has a neuroprotective effect in mouse models of retinitis pigmentosa, a hereditary, progressive neurodegenerative disease that leads to blindness. Various LD radiation doses were administered to the eyes in a retinal degeneration mouse model, and their pathological and physiological effects were analyzed. LD gamma radiation in a low-dose-rate (LDR) condition rescues photoreceptor cell apoptosis both morphologically and functionally. The greatest effect was observed in a condition using 650 mGy irradiation and a 26 mGy/minute dose rate. Multiple rounds of irradiation strengthened this neuroprotective effect. A characteristic up-regulation (563%) of antioxidative gene peroxiredoxin-2 (Prdx2) in the LDR-LD-irradiated retina was observed compared to the sham-treated control retina. Silencing the Prdx2 using small-interfering RNA administration reduced the LDR-LD rescue effect on the photoreceptors. Our results demonstrate for the first time that LDR-LD irradiation has a biological effect in neural cells of living animals. The results support that radiation exhibits hormesis, and this effect may be applied as a novel therapeutic concept for retinitis pigmentosa and for other progressive neurodegenerative diseases regardless of the mechanism of degeneration involved.
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Affiliation(s)
- Atsushi Otani
- Department of Ophthalmology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
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Wong IYH, Poon MW, Pang RTW, Lian Q, Wong D. Promises of stem cell therapy for retinal degenerative diseases. Graefes Arch Clin Exp Ophthalmol 2011; 249:1439-48. [PMID: 21866334 PMCID: PMC3178027 DOI: 10.1007/s00417-011-1764-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 05/19/2011] [Accepted: 07/28/2011] [Indexed: 12/31/2022] Open
Abstract
With the development of stem cell technology, stem cell-based therapy for retinal degeneration has been proposed to restore the visual function. Many animal studies and some clinical trials have shown encouraging results of stem cell-based therapy in retinal degenerative diseases. While stem cell-based therapy is a promising strategy to replace damaged retinal cells and ultimately cure retinal degeneration, there are several important challenges which need to be overcome before stem cell technology can be applied widely in clinical settings. In this review, different types of donor cell origins used in retinal treatments, potential target cell types for therapy, methods of stem cell delivery to the eye, assessments of potential risks in stem cell therapy, as well as future developments of retinal stem cells therapy, will be discussed.
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Affiliation(s)
- Ian Yat-Hin Wong
- Department of Medicine and Eye Institute, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong SAR, PRC
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Shen D, Cao X, Zhao L, Tuo J, Wong WT, Chan CC. Naloxone ameliorates retinal lesions in Ccl2/Cx3cr1 double-deficient mice via modulation of microglia. Invest Ophthalmol Vis Sci 2011; 52:2897-904. [PMID: 21245403 DOI: 10.1167/iovs.10-6114] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
PURPOSE The role of naloxone, an opioid receptor antagonist, on microglial inhibition and neuroprotective effects has been reported in lipopolysaccharide (LPS)-induced neurodegeneration and light-induced photoreceptor degeneration. The authors evaluated the effects of naloxone on Ccl2(-/-)/Cx3cr1(-/-) (DKO) mice, a murine model of age-related macular degeneration (AMD). METHODS Two-month-old DKO and wild-type controls were given daily intraperitoneal injections of naloxone or PBS for 2 months. Animals were examined monthly by funduscopy. Ocular tissue was analyzed histologically and in retinal flat mount preparations. Ocular A2E was measured using HPLC. Quantitative RT-PCR analyzed TNF-α, IL-1β, IL-10 and TLR4 transcripts in the DKO eyes and LPS activated culture microglial cells. Serum nitrite was measured using Griess colorimetric reaction. RESULTS Naloxone ameliorated the clinical progression and severity of retinal lesions in the DKO mice compared with those of untreated controls. Histopathology also showed less focal retinal degeneration in the treated DKO mice than in controls. The aggregation of microglia in the outer retina in DKO mice was significantly reduced in naloxone-treated animals compared with control untreated DKO. Ocular TNF-α, IL-1β, and TLR4 transcripts and A2E were significantly lower in naloxone-treated DKO animals and cultured microglial cells than in controls, as were serum nitrite levels. CONCLUSIONS Naloxone significantly reduces the progress of retinal lesions in DKO mice. Naloxone modulates microglia accumulation and activation at the site of retinal degeneration, which may be mediated by inhibition of the proinflammatory molecules of NO, TNF-α, and IL-β. The potential therapeutic effects of naloxone on retinal degeneration, including AMD, warrants further investigation.
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Affiliation(s)
- Defen Shen
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892-1857, USA
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48
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Bramall AN, Wright AF, Jacobson SG, McInnes RR. The genomic, biochemical, and cellular responses of the retina in inherited photoreceptor degenerations and prospects for the treatment of these disorders. Annu Rev Neurosci 2011; 33:441-72. [PMID: 20572772 DOI: 10.1146/annurev-neuro-060909-153227] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The association of more than 140 genes with human photoreceptor degenerations, together with studies of animal models of these monogenic diseases, has provided great insight into their pathogenesis. Here we review the responses of the retina to photoreceptor mutations, including mechanisms of photoreceptor death. We discuss the roles of oxidative metabolism, mitochondrial reactive oxygen species, metabolic stress, protein misfolding, and defects in ciliary proteins, as well as the responses of Müller glia, microglia, and the retinal vasculature. Finally, we report on potential pharmacologic and biologic therapies, the critical role of histopathology as a prerequisite to treatment, and the exciting promise of gene therapy in animal models and in phase 1 trials in humans.
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Affiliation(s)
- Alexa N Bramall
- Programs in Genetics and Developmental Biology, The Research Institute, The Hospital for Sick Children, Toronto M5G1L7, Canada.
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Granulocyte colony-stimulating factor attenuates oxidative stress-induced apoptosis in vascular endothelial cells and exhibits functional and morphologic protective effect in oxygen-induced retinopathy. Blood 2010; 117:1091-100. [PMID: 21059898 DOI: 10.1182/blood-2010-05-286963] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Granulocyte colony-stimulating factor (G-CSF) is a known hematopoietic glycoprotein, and recent studies have revealed that G-CSF possesses other interesting properties. Oxidative stress is involved in many diseases, such as atherosclerosis, heart failure, myocardial infarction, Alzheimer disease, and diabetic retinopathy. This study was designed to examine whether G-CSF has a protective effect on endothelial cells against oxidative stress and to investigate whether G-CSF has a therapeutic role in ischemic vascular diseases. Expression of G-CSF (P < .01) and G-CSF receptor (P < .05) mRNA in human retinal endothelial cells (HRECs) was significantly up-regulated by oxidative stress. Treatment with 100 ng/mL G-CSF significantly reduced H(2)O(2)-induced apoptosis in HRECs from 61.7% to 41.4% (P < .05). Akt was phosphorylated in HRECs by G-CSF addition, and LY294002, a PI3K inhibitor, significantly attenuated the antiapoptotic effect of G-CSF (by 44.1%, P < .05). The rescue effect was also observed in human umbilical vein endothelial cells. In mouse oxygen-induced retinopathy model, G-CSF significantly reduced vascular obliteration (P < .01) and neovascular tuft formation (P < .01). G-CSF treatment also clearly rescued the functional and morphologic deterioration of the neural retina. A possibility of a novel therapeutic strategy for ischemic diseases through attenuating vascular regression using G-CSF was proposed.
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Otsuka H, Arimura N, Sonoda S, Nakamura M, Hashiguchi T, Maruyama I, Nakao S, Hafezi-Moghadam A, Sakamoto T. Stromal cell-derived factor-1 is essential for photoreceptor cell protection in retinal detachment. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 177:2268-77. [PMID: 20889568 DOI: 10.2353/ajpath.2010.100134] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Stromal cell-derived factor-1 (SDF-1) causes chemotaxis of CXCR4-expressing bone marrow-derived cells. SDF-1 is involved in the pathogenesis of various vascular diseases, including those of the eye. However, the role of SDF-1 in neuronal diseases is not completely understood. Here, we show higher SDF-1 levels in the vitreous humor of patients with retinal detachment (RD) compared with normal patients. SDF-1 correlated positively with the duration as well as the extent of RD. Furthermore, SDF-1 correlated significantly with levels of interleukin-6 and interleukin-8, but not with vascular endothelial growth factor. Western blot analysis results showed significant SDF-1 up-regulation in detached rat retinas compared with normal animals. Immunohistochemistry data showed that SDF-1 was co-localized with the glial cells of the detached retina. SDF-1 blockade with a neutralizing antibody increased photoreceptor cell loss and macrophage accumulation in the subretinal space. The retinal precursor cell line R28 expressed CXCR4. SDF-1 rescued serum starvation-induced apoptosis in R28 cells and enhanced their ability to participate in wound closure in a scratch assay. Our results indicate a surprising, protective role for SDF-1 in RD. This effect may be mediated directly or indirectly through other cell types.
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Affiliation(s)
- Hiroki Otsuka
- Department of Ophthalmology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1, Sakuragaoka, Kagoshima, 890-8520, Japan
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