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Peterson SL, Li Y, Sun CJ, Wong KA, Leung KS, de Lima S, Hanovice NJ, Yuki K, Stevens B, Benowitz LI. Retinal Ganglion Cell Axon Regeneration Requires Complement and Myeloid Cell Activity within the Optic Nerve. J Neurosci 2021; 41:8508-8531. [PMID: 34417332 PMCID: PMC8513703 DOI: 10.1523/jneurosci.0555-21.2021] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 07/21/2021] [Accepted: 08/16/2021] [Indexed: 01/01/2023] Open
Abstract
Axon regenerative failure in the mature CNS contributes to functional deficits following many traumatic injuries, ischemic injuries, and neurodegenerative diseases. The complement cascade of the innate immune system responds to pathogen threat through inflammatory cell activation, pathogen opsonization, and pathogen lysis, and complement is also involved in CNS development, neuroplasticity, injury, and disease. Here, we investigated the involvement of the classical complement cascade and microglia/monocytes in CNS repair using the mouse optic nerve injury (ONI) model, in which axons arising from retinal ganglion cells (RGCs) are disrupted. We report that central complement C3 protein and mRNA, classical complement C1q protein and mRNA, and microglia/monocyte phagocytic complement receptor CR3 all increase in response to ONI, especially within the optic nerve itself. Importantly, genetic deletion of C1q, C3, or CR3 attenuates RGC axon regeneration induced by several distinct methods, with minimal effects on RGC survival. Local injections of C1q function-blocking antibody revealed that complement acts primarily within the optic nerve, not retina, to support regeneration. Moreover, C1q opsonizes and CR3+ microglia/monocytes phagocytose growth-inhibitory myelin debris after ONI, a likely mechanism through which complement and myeloid cells support axon regeneration. Collectively, these results indicate that local optic nerve complement-myeloid phagocytic signaling is required for CNS axon regrowth, emphasizing the axonal compartment and highlighting a beneficial neuroimmune role for complement and microglia/monocytes in CNS repair.SIGNIFICANCE STATEMENT Despite the importance of achieving axon regeneration after CNS injury and the inevitability of inflammation after such injury, the contributions of complement and microglia to CNS axon regeneration are largely unknown. Whereas inflammation is commonly thought to exacerbate the effects of CNS injury, we find that complement proteins C1q and C3 and microglia/monocyte phagocytic complement receptor CR3 are each required for retinal ganglion cell axon regeneration through the injured mouse optic nerve. Also, whereas studies of optic nerve regeneration generally focus on the retina, we show that the regeneration-relevant role of complement and microglia/monocytes likely involves myelin phagocytosis within the optic nerve. Thus, our results point to the importance of the innate immune response for CNS repair.
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Affiliation(s)
- Sheri L Peterson
- Laboratories for Neuroscience Research in Neurosurgery
- Department of Neurosurgery
- F.M. Kirby Neurobiology Center, and
- Department of Neurosurgery and
| | - Yiqing Li
- Laboratories for Neuroscience Research in Neurosurgery
- Department of Neurosurgery
- F.M. Kirby Neurobiology Center, and
- Department of Neurosurgery and
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong China, 510060
| | - Christina J Sun
- Laboratories for Neuroscience Research in Neurosurgery
- Department of Neurosurgery
| | - Kimberly A Wong
- Laboratories for Neuroscience Research in Neurosurgery
- Department of Neurosurgery
- F.M. Kirby Neurobiology Center, and
- Department of Neurosurgery and
| | - Kylie S Leung
- Laboratories for Neuroscience Research in Neurosurgery
- Department of Neurosurgery
| | - Silmara de Lima
- Laboratories for Neuroscience Research in Neurosurgery
- Department of Neurosurgery
- F.M. Kirby Neurobiology Center, and
- Department of Neurosurgery and
| | - Nicholas J Hanovice
- Laboratories for Neuroscience Research in Neurosurgery
- Department of Neurosurgery
- F.M. Kirby Neurobiology Center, and
- Department of Neurosurgery and
| | - Kenya Yuki
- Laboratories for Neuroscience Research in Neurosurgery
- Department of Neurosurgery
- F.M. Kirby Neurobiology Center, and
- Department of Neurosurgery and
| | - Beth Stevens
- F.M. Kirby Neurobiology Center, and
- Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142
| | - Larry I Benowitz
- Laboratories for Neuroscience Research in Neurosurgery
- Department of Neurosurgery
- F.M. Kirby Neurobiology Center, and
- Department of Neurosurgery and
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02115
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52
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Sharif NA. Therapeutic Drugs and Devices for Tackling Ocular Hypertension and Glaucoma, and Need for Neuroprotection and Cytoprotective Therapies. Front Pharmacol 2021; 12:729249. [PMID: 34603044 PMCID: PMC8484316 DOI: 10.3389/fphar.2021.729249] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/18/2021] [Indexed: 12/11/2022] Open
Abstract
Damage to the optic nerve and the death of associated retinal ganglion cells (RGCs) by elevated intraocular pressure (IOP), also known as glaucoma, is responsible for visual impairment and blindness in millions of people worldwide. The ocular hypertension (OHT) and the deleterious mechanical forces it exerts at the back of the eye, at the level of the optic nerve head/optic disc and lamina cribosa, is the only modifiable risk factor associated with glaucoma that can be treated. The elevated IOP occurs due to the inability of accumulated aqueous humor (AQH) to egress from the anterior chamber of the eye due to occlusion of the major outflow pathway, the trabecular meshwork (TM) and Schlemm’s canal (SC). Several different classes of pharmaceutical agents, surgical techniques and implantable devices have been developed to lower and control IOP. First-line drugs to promote AQH outflow via the uveoscleral outflow pathway include FP-receptor prostaglandin (PG) agonists (e.g., latanoprost, travoprost and tafluprost) and a novel non-PG EP2-receptor agonist (omidenepag isopropyl, Eybelis®). TM/SC outflow enhancing drugs are also effective ocular hypotensive agents (e.g., rho kinase inhibitors like ripasudil and netarsudil; and latanoprostene bunod, a conjugate of a nitric oxide donor and latanoprost). One of the most effective anterior chamber AQH microshunt devices is the Preserflo® microshunt which can lower IOP down to 10–13 mmHg. Other IOP-lowering drugs and devices on the horizon will be also discussed. Additionally, since elevated IOP is only one of many risk factors for development of glaucomatous optic neuropathy, a treatise of the role of inflammatory neurodegeneration of the optic nerve and retinal ganglion cells and appropriate neuroprotective strategies to mitigate this disease will also be reviewed and discussed.
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Affiliation(s)
- Najam A Sharif
- Global Alliances and External Research, Ophthalmology Innovation Center, Santen Inc., Emeryville, CA, United States
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Guo M, Schwartz TD, Dunaief JL, Cui QN. Myeloid cells in retinal and brain degeneration. FEBS J 2021; 289:2337-2361. [PMID: 34478598 PMCID: PMC8891394 DOI: 10.1111/febs.16177] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 08/06/2021] [Accepted: 09/02/2021] [Indexed: 12/11/2022]
Abstract
Retinal inflammation underlies multiple prevalent ocular and neurological diseases. Similar inflammatory processes are observed in glaucomatous optic neuropathy, age-related macular degeneration, retinitis pigmentosa, posterior uveitis, Alzheimer's disease, and Parkinson's disease. In particular, human and animal studies have demonstrated the important role microglia/macrophages play in initiating and maintaining a pro-inflammatory environment in degenerative processes impacting vision. On the other hand, microglia have also been shown to have a protective role in multiple central nervous system diseases. Identifying the mechanisms underlying cell dysfunction and death is the first step toward developing novel therapeutics for these diseases impacting the central nervous system. In addition to reviewing recent key studies defining important mediators of retinal inflammation, with an emphasis on translational studies that bridge this research from bench to bedside, we also highlight a promising therapeutic class of medications, the glucagon-like peptide-1 receptor agonists. Finally, we propose areas where additional research is necessary to identify mechanisms that can be modulated to shift the balance from a neurotoxic to a neuroprotective retinal environment.
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Affiliation(s)
- Michelle Guo
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Turner D Schwartz
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Joshua L Dunaief
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Qi N Cui
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
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54
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Simó R, Simó-Servat O, Bogdanov P, Hernández C. Neurovascular Unit: A New Target for Treating Early Stages of Diabetic Retinopathy. Pharmaceutics 2021; 13:pharmaceutics13081320. [PMID: 34452281 PMCID: PMC8399715 DOI: 10.3390/pharmaceutics13081320] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 08/18/2021] [Accepted: 08/19/2021] [Indexed: 01/02/2023] Open
Abstract
The concept of diabetic retinopathy as a microvascular disease has evolved and is now considered a more complex diabetic complication in which neurovascular unit impairment plays an essential role and, therefore, can be considered as a main therapeutic target in the early stages of the disease. However, neurodegeneration is not always the apparent primary event in the natural story of diabetic retinopathy, and a phenotyping characterization is recommendable to identify those patients in whom neuroprotective treatment might be of benefit. In recent years, a myriad of treatments based on neuroprotection have been tested in experimental models, but more interestingly, there are drugs with a dual activity (neuroprotective and vasculotropic). In this review, the recent evidence concerning the therapeutic approaches targeting neurovascular unit impairment will be presented, along with a critical review of the scientific gaps and problems which remain to be overcome before our knowledge can be transferred to clinical practice.
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Affiliation(s)
- Rafael Simó
- Diabetes and Metabolism Research Unit, Vall d’Hebron Research Institute (VHIR), 08035 Barcelona, Spain; (O.S.-S.); (P.B.); (C.H.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain
- Correspondence:
| | - Olga Simó-Servat
- Diabetes and Metabolism Research Unit, Vall d’Hebron Research Institute (VHIR), 08035 Barcelona, Spain; (O.S.-S.); (P.B.); (C.H.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain
| | - Patricia Bogdanov
- Diabetes and Metabolism Research Unit, Vall d’Hebron Research Institute (VHIR), 08035 Barcelona, Spain; (O.S.-S.); (P.B.); (C.H.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain
| | - Cristina Hernández
- Diabetes and Metabolism Research Unit, Vall d’Hebron Research Institute (VHIR), 08035 Barcelona, Spain; (O.S.-S.); (P.B.); (C.H.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain
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55
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Immune Responses in the Glaucomatous Retina: Regulation and Dynamics. Cells 2021; 10:cells10081973. [PMID: 34440742 PMCID: PMC8391899 DOI: 10.3390/cells10081973] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 12/27/2022] Open
Abstract
Glaucoma is a multifactorial disease resulting in progressive vision loss due to retinal ganglion cell (RGC) dysfunction and death. Early events in the pathobiology of the disease include oxidative, metabolic, or mechanical stress that acts upon RGC, causing these to rapidly release danger signals, including extracellular ATP, resulting in micro- and macroglial activation and neuroinflammation. Danger signaling also leads to the formation of inflammasomes in the retina that enable maturation of proinflammatory cytokines such IL-1β and IL-18. Chronic neuroinflammation can have directly damaging effects on RGC, but it also creates a proinflammatory environment and compromises the immune privilege of the retina. In particular, continuous synthesis of proinflammatory mediators such as TNFα, IL-1β, and anaphylatoxins weakens the blood–retina barrier and recruits or activates T-cells. Recent data have demonstrated that adaptive immune responses strongly exacerbate RGC loss in animal models of the disease as T-cells appear to target heat shock proteins displayed on the surface of stressed RGC to cause their apoptotic death. It is possible that dysregulation of these immune responses contributes to the continued loss of RGC in some patients.
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56
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Schmitt HM, Fehrman RL, Maes ME, Yang H, Guo LW, Schlamp CL, Pelzel HR, Nickells RW. Increased Susceptibility and Intrinsic Apoptotic Signaling in Neurons by Induced HDAC3 Expression. Invest Ophthalmol Vis Sci 2021; 62:14. [PMID: 34398198 PMCID: PMC8375002 DOI: 10.1167/iovs.62.10.14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 07/05/2021] [Indexed: 12/12/2022] Open
Abstract
Purpose Inhibition or targeted deletion of histone deacetylase 3 (HDAC3) is neuroprotective in a variety neurodegenerative conditions, including retinal ganglion cells (RGCs) after acute optic nerve damage. Consistent with this, induced HDAC3 expression in cultured cells shows selective toxicity to neurons. Despite an established role for HDAC3 in neuronal pathology, little is known regarding the mechanism of this pathology. Methods Induced expression of an HDAC3-mCherry fusion protein in mouse RGCs was accomplished by transduction with AAV2/2-Pgk-HDAC3-mCherry. Increased susceptibility to optic nerve damage in HDAC3-mCherry expressing RGCs was evaluated in transduced mice that received acute optic nerve crush surgery. Expression of HDAC3-FLAG or HDAC3-mCherry was induced by nucleofection or transfection of plasmids into differentiated or undifferentiated 661W tissue culture cells. Immunostaining for cleaved caspase 3, localization of a GFP-BAX fusion protein, and quantitative RT-PCR was used to evaluate HDAC3-induced damage. Results Induced expression of exogenous HDAC3 in RGCs by viral-mediated gene transfer resulted in modest levels of cell death but significantly increased the sensitivity of these neurons to axonal damage. Undifferentiated 661W retinal precursor cells were resilient to induced HDAC3 expression, but after differentiation, HDAC3 induced GFP-BAX recruitment to the mitochondria and BAX/BAK dependent activation of caspase 3. This was accompanied by an increase in accumulation of transcripts for the JNK2/3 kinases and the p53-regulated BH3-only gene Bbc3/Puma. Cell cycle arrest of undifferentiated 661W cells did not increase their sensitivity to HDAC3 expression. Conclusions Collectively, these results indicate that HDAC3-induced toxicity to neurons is mediated by the intrinsic apoptotic pathway.
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Affiliation(s)
- Heather M. Schmitt
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison WI, United States
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, United States
- Department of Ophthalmology, Duke University, Durham, NC, United States
| | - Rachel L. Fehrman
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison WI, United States
| | - Margaret E. Maes
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Huan Yang
- Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States
| | - Lian-Wang Guo
- Department of Surgery, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Cassandra L. Schlamp
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison WI, United States
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, United States
| | - Heather R. Pelzel
- Department of Biological Sciences, University of Wisconsin-Whitewater, Whitewater, WI, United States
| | - Robert W. Nickells
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison WI, United States
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, United States
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Early Functional Impairment in Experimental Glaucoma Is Accompanied by Disruption of the GABAergic System and Inceptive Neuroinflammation. Int J Mol Sci 2021; 22:ijms22147581. [PMID: 34299211 PMCID: PMC8306430 DOI: 10.3390/ijms22147581] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 12/21/2022] Open
Abstract
Glaucoma is a leading cause of irreversible blindness worldwide, and increased intraocular pressure (IOP) is a major risk factor. We aimed to determine if early functional and molecular differences in the glaucomatous retina manifest before significant retinal ganglion cell (RGC) loss is apparent. Adenoviral vectors expressing a pathogenic form of myocilin (Ad5.MYOC) were used to induce IOP elevation in C57BL/6 mice. IOP and pattern electroretinograms (pERG) were recorded, and retinas were prepared for RNA sequencing, immunohistochemistry, or to determine RGC loss. Ocular injection of Ad5.MYOC leads to reliable IOP elevation, resulting in significant loss of RGC after nine weeks. A significant decrease in the pERG amplitude was evident in eyes three weeks after IOP elevation. Retinal gene expression analysis revealed increased expression for 291 genes related to complement cascade, inflammation, and antigen presentation in hypertensive eyes. Decreased expression was found for 378 genes associated with the γ-aminobutyric acid (GABA)ergic and glutamatergic systems and axon guidance. These data suggest that early functional changes in RGC might be due to reduced GABAA receptor signaling and neuroinflammation that precedes RGC loss in this glaucoma model. These initial changes may offer new targets for early detection of glaucoma and the development of new interventions.
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58
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Cockram TOJ, Dundee JM, Popescu AS, Brown GC. The Phagocytic Code Regulating Phagocytosis of Mammalian Cells. Front Immunol 2021; 12:629979. [PMID: 34177884 PMCID: PMC8220072 DOI: 10.3389/fimmu.2021.629979] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 05/18/2021] [Indexed: 01/21/2023] Open
Abstract
Mammalian phagocytes can phagocytose (i.e. eat) other mammalian cells in the body if they display certain signals, and this phagocytosis plays fundamental roles in development, cell turnover, tissue homeostasis and disease prevention. To phagocytose the correct cells, phagocytes must discriminate which cells to eat using a 'phagocytic code' - a set of over 50 known phagocytic signals determining whether a cell is eaten or not - comprising find-me signals, eat-me signals, don't-eat-me signals and opsonins. Most opsonins require binding to eat-me signals - for example, the opsonins galectin-3, calreticulin and C1q bind asialoglycan eat-me signals on target cells - to induce phagocytosis. Some proteins act as 'self-opsonins', while others are 'negative opsonins' or 'phagocyte suppressants', inhibiting phagocytosis. We review known phagocytic signals here, both established and novel, and how they integrate to regulate phagocytosis of several mammalian targets - including excess cells in development, senescent and aged cells, infected cells, cancer cells, dead or dying cells, cell debris and neuronal synapses. Understanding the phagocytic code, and how it goes wrong, may enable novel therapies for multiple pathologies with too much or too little phagocytosis, such as: infectious disease, cancer, neurodegeneration, psychiatric disease, cardiovascular disease, ageing and auto-immune disease.
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Affiliation(s)
| | | | | | - Guy C. Brown
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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59
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Axonopathy precedes cell death in ocular damage mediated by blast exposure. Sci Rep 2021; 11:11774. [PMID: 34083587 PMCID: PMC8175471 DOI: 10.1038/s41598-021-90412-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 05/04/2021] [Indexed: 12/13/2022] Open
Abstract
Traumatic brain injuries (TBI) of varied types are common across all populations and can cause visual problems. For military personnel in combat settings, injuries from blast exposures (bTBI) are prevalent and arise from a myriad of different situations. To model these diverse conditions, we are one of several groups modeling bTBI using mice in varying ways. Here, we report a refined analysis of retinal ganglion cell (RGC) damage in male C57BL/6J mice exposed to a blast-wave in an enclosed chamber. Ganglion cell layer thickness, RGC density (BRN3A and RBPMS immunoreactivity), cellular density of ganglion cell layer (hematoxylin and eosin staining), and axon numbers (paraphenylenediamine staining) were quantified at timepoints ranging from 1 to 17-weeks. RNA sequencing was performed at 1-week and 5-weeks post-injury. Earliest indices of damage, evident by 1-week post-injury, are a loss of RGC marker expression, damage to RGC axons, and increase in glial markers expression. Blast exposure caused a loss of RGC somas and axons—with greatest loss occurring by 5-weeks post-injury. While indices of glial involvement are prominent early, they quickly subside as RGCs are lost. The finding that axonopathy precedes soma loss resembles pathology observed in mouse models of glaucoma, suggesting similar mechanisms.
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60
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Multifactorial Pathogenic Processes of Retinal Ganglion Cell Degeneration in Glaucoma towards Multi-Target Strategies for Broader Treatment Effects. Cells 2021; 10:cells10061372. [PMID: 34199494 PMCID: PMC8228726 DOI: 10.3390/cells10061372] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/14/2021] [Accepted: 05/29/2021] [Indexed: 02/06/2023] Open
Abstract
Glaucoma is a chronic neurodegenerative disease characterized by apoptosis of retinal ganglion cell (RGC) somas, degeneration of axons, and loss of synapses at dendrites and axon terminals. Glaucomatous neurodegeneration encompasses multiple triggers, multiple cell types, and multiple molecular pathways through the etiological paths with biomechanical, vascular, metabolic, oxidative, and inflammatory components. As much as intrinsic responses of RGCs themselves, divergent responses and intricate interactions of the surrounding glia also play decisive roles for the cell fate. Seen from a broad perspective, multitarget treatment strategies have a compelling pathophysiological basis to more efficiently manipulate multiple pathogenic processes at multiple injury sites in such a multifactorial neurodegenerative disease. Despite distinct molecular programs for somatic and axonal degeneration, mitochondrial dysfunction and glia-driven neuroinflammation present interdependent processes with widespread impacts in the glaucomatous retina and optic nerve. Since dysfunctional mitochondria stimulate inflammatory responses and proinflammatory mediators impair mitochondria, mitochondrial restoration may be immunomodulatory, while anti-inflammatory treatments protect mitochondria. Manipulation of these converging routes may thus allow a unified treatment strategy to protect RGC axons, somas, and synapses. This review presents an overview of recent research advancements with emphasis on potential treatment targets to achieve the best treatment efficacy to preserve visual function in glaucoma.
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Wang J, Struebing FL, Geisert EE. Commonalities of optic nerve injury and glaucoma-induced neurodegeneration: Insights from transcriptome-wide studies. Exp Eye Res 2021; 207:108571. [PMID: 33844961 PMCID: PMC9890784 DOI: 10.1016/j.exer.2021.108571] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 03/28/2021] [Accepted: 04/02/2021] [Indexed: 02/03/2023]
Abstract
Glaucoma is a collection of diseases that lead to an irreversible vision loss due to damage of retinal ganglion cells (RGCs). Although the underlying events leading to RGC death are not fully understood, recent research efforts are beginning to define the genetic changes that play a critical role in the initiation and progression of glaucomatous injury and RGC death. Several genetic and experimental animal models have been developed to mimic glaucomatous neurodegeneration. These models differ in many respects but all result in the loss of RGCs. Assessing transcriptional changes across different models could provide a more complete perspective on the molecular drivers of RGC degeneration. For the past several decades, changes in the retinal transcriptome during neurodegeneration process were defined using microarray methods, RNA sequencing and now single cell RNA sequencing. It is understood that these methods have strengths and weaknesses due to technical differences and variations in the analytical tools used. In this review, we focus on the use of transcriptome-wide expression profiling of the changes occurring as RGCs are lost across different glaucoma models. Commonalities of optic nerve crush and glaucoma-induced neurodegeneration are identified and discussed.
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Affiliation(s)
- Jiaxing Wang
- Emory Eye Center, Department of Ophthalmology, Emory University, 1365B Clifton Road NE, Atlanta, GA, 30322, USA
| | - Felix L. Struebing
- Center for Neuropathology and Prion Research, Ludwig Maximilian University of Munich, Germany,Department for Translational Brain Research, German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Eldon E. Geisert
- Emory Eye Center, Department of Ophthalmology, Emory University, 1365B Clifton Road NE, Atlanta, GA, 30322, USA,Corresponding author: (E.E. Geisert)
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62
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Tribble JR, Otmani A, Sun S, Ellis SA, Cimaglia G, Vohra R, Jöe M, Lardner E, Venkataraman AP, Domínguez-Vicent A, Kokkali E, Rho S, Jóhannesson G, Burgess RW, Fuerst PG, Brautaset R, Kolko M, Morgan JE, Crowston JG, Votruba M, Williams PA. Nicotinamide provides neuroprotection in glaucoma by protecting against mitochondrial and metabolic dysfunction. Redox Biol 2021; 43:101988. [PMID: 33932867 PMCID: PMC8103000 DOI: 10.1016/j.redox.2021.101988] [Citation(s) in RCA: 89] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/06/2021] [Accepted: 04/20/2021] [Indexed: 12/16/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD) is a REDOX cofactor and metabolite essential for neuronal survival. Glaucoma is a common neurodegenerative disease in which neuronal levels of NAD decline. We assess the effects of nicotinamide (a precursor to NAD) on retinal ganglion cells (the affected neuron in glaucoma) in normal physiological conditions and across a range of glaucoma relevant insults including mitochondrial stress and axon degenerative insults. We demonstrate retinal ganglion cell somal, axonal, and dendritic neuroprotection by nicotinamide in rodent models which represent isolated ocular hypertensive, axon degenerative, and mitochondrial degenerative insults. We performed metabolomics enriched for small molecular weight metabolites for the retina, optic nerve, and superior colliculus which demonstrates that ocular hypertension induces widespread metabolic disruption, including consistent changes to α-ketoglutaric acid, creatine/creatinine, homocysteine, and glycerophosphocholine. This metabolic disruption is prevented by nicotinamide. Nicotinamide provides further neuroprotective effects by increasing oxidative phosphorylation, buffering and preventing metabolic stress, and increasing mitochondrial size and motility whilst simultaneously dampening action potential firing frequency. These data support continued determination of the utility of long-term nicotinamide treatment as a neuroprotective therapy for human glaucoma. Nicotinamide is neuroprotective in cell and animal models that recapitulate isolated features of glaucoma. Systemic nicotinamide administration has limited molecular side-effects on visual system tissue under basal conditions. Nicotinamide provides a robust reversal in the disease metabolic profile of glaucomatous animals. Nicotinamide increases oxidative phosphorylation, buffers and prevents metabolic stress, and increases mitochondrial size.
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Affiliation(s)
- James R Tribble
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Amin Otmani
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Shanshan Sun
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.
| | - Sevannah A Ellis
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Australia.
| | - Gloria Cimaglia
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden; School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.
| | - Rupali Vohra
- Department of Veterinary and Animal Sciences, Pathobiological Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Department of Drug Design and Pharmacology, Eye Translational Research Unit, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
| | - Melissa Jöe
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Emma Lardner
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Abinaya P Venkataraman
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Alberto Domínguez-Vicent
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Eirini Kokkali
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.
| | - Seungsoo Rho
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK; Department of Ophthalmology, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea.
| | - Gauti Jóhannesson
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden; Wallenberg Centre of Molecular Medicine, Umeå University, Umeå, Sweden.
| | | | - Peter G Fuerst
- WWAMI Medical Education Program, University of Idaho, Moscow, ID, USA.
| | - Rune Brautaset
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Miriam Kolko
- Department of Drug Design and Pharmacology, Eye Translational Research Unit, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet-Glostrup, Glostrup, Denmark.
| | - James E Morgan
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK; Cardiff Eye Unit, University Hospital Wales, Cardiff, UK; School of Medicine, Cardiff University, Cardiff, UK.
| | - Jonathan G Crowston
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore; Centre for Vision Research, Neuroscience and Behavioural Disorders, Duke-NUS, Singapore, Singapore.
| | - Marcela Votruba
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK; Cardiff Eye Unit, University Hospital Wales, Cardiff, UK.
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
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Butler CA, Popescu AS, Kitchener EJA, Allendorf DH, Puigdellívol M, Brown GC. Microglial phagocytosis of neurons in neurodegeneration, and its regulation. J Neurochem 2021; 158:621-639. [PMID: 33608912 DOI: 10.1111/jnc.15327] [Citation(s) in RCA: 118] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 01/13/2021] [Accepted: 02/10/2021] [Indexed: 02/06/2023]
Abstract
There is growing evidence that excessive microglial phagocytosis of neurons and synapses contributes to multiple brain pathologies. RNA-seq and genome-wide association (GWAS) studies have linked multiple phagocytic genes to neurodegenerative diseases, and knock-out of phagocytic genes has been found to protect against neurodegeneration in animal models, suggesting that excessive microglial phagocytosis contributes to neurodegeneration. Here, we review recent evidence that microglial phagocytosis of live neurons and synapses causes neurodegeneration in animal models of Alzheimer's disease and other tauopathies, Parkinson's disease, frontotemporal dementias, multiple sclerosis, retinal degeneration and neurodegeneration induced by ischaemia, infection or ageing. We also review factors regulating microglial phagocytosis of neurons, including: nucleotides, frackalkine, phosphatidylserine, calreticulin, UDP, CD47, sialylation, complement, galectin-3, Apolipoprotein E, phagocytic receptors, Siglec receptors, cytokines, microglial epigenetics and expression profile. Some of these factors may be potential treatment targets to prevent neurodegeneration mediated by excessive microglial phagocytosis of live neurons and synapses.
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Affiliation(s)
- Claire A Butler
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Alma S Popescu
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | | | | | - Mar Puigdellívol
- Department of Biochemistry, University of Cambridge, Cambridge, UK.,Departament de Biomedicina, Facultat de Medicina, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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New perspectives of immunomodulation and neuroprotection in glaucoma. Cent Eur J Immunol 2021; 46:105-110. [PMID: 33897291 PMCID: PMC8056344 DOI: 10.5114/ceji.2021.104329] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/21/2020] [Indexed: 02/07/2023] Open
Abstract
Glaucoma is the neurodegenerative disease of retinal ganglion cells. The main risk factor for glaucoma is increased intraocular pressure. The processes leading to cell death due to presence of the injury factor comprise multiple molecular mechanisms, as well as the immunological response. The knowledge of immunological mechanisms occurring in glaucomatous degeneration makes it possible to introduce glaucoma treatment modulating the cellular degradation. The glaucoma treatment of the future will make it possible not only to lower the intraocular pressure, but also to moderate the intracellular mechanisms in order to prevent retinal cell degeneration. Citicoline is a drug modulating glutamate excitotoxicity that is already in use. Rho kinase inhibitors were found to stimulate neurite growth and axon regeneration apart from lowering intraocular pressure. The complementary action of brimonidine is to increase neurotrophic factor (NTF) concentrations and inhibit glutamate toxicity. Immunomodulatory therapies with antibodies and gene therapies show promising effects in the current studies. The supplementation of NTFs prevents glaucomatous damage. Resveratrol and other antioxidants inhibit reactive oxygen species formation. Cell transplantation of stem cells, Schwann cells and nerve extracts was reported to be successful so far. Our review presents the most promising new strategies of neuroprotection and immunomodulation in glaucoma.
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65
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Samelska K, Zaleska-Żmijewska A, Bałan B, Grąbczewski A, Szaflik JP, Kubiak AJ, Skopiński P. Immunological and molecular basics of the primary open angle glaucoma pathomechanism. Cent Eur J Immunol 2021; 46:111-117. [PMID: 33897292 PMCID: PMC8056342 DOI: 10.5114/ceji.2021.104328] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/26/2020] [Indexed: 02/07/2023] Open
Abstract
Glaucoma is a degenerative process of the optic nerve. Increased intraocular pressure is believed to be the main factor leading to the glaucomatous damage. The in vitro and in vivo animal glaucoma research models provide insight into the molecular changes in the retina in response to the injury factor. The damage is a complex process incorporating molecular and immunological changes. Such changes involve NF kB activity and complement activation. The processes affect the human antigen, JNK, MAPK, p53, MT2 and DBA/2J molecular pathways, activate the autophagy processes and compromise neuroprotective mechanisms. Activation and inhibition of immunological responses contribute to cell injury. The immunological mechanisms of glaucomatous degeneration include glial response, the complement, tumor necrosis factor α (TNF-α) pathways and toll-like receptors athways. Oxidative stress and excitotoxicity are factors contributing to cell death in glaucoma. The authors present an up-to-date review of the mechanisms involved and update on research focusing on a possible innovative glaucoma treatment.
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Affiliation(s)
- Katarzyna Samelska
- SPKSO Ophthalmic University Hospital, Warsaw, Poland
- Department of Ophthalmology, Medical University of Warsaw, Warsaw, Poland
| | - Anna Zaleska-Żmijewska
- SPKSO Ophthalmic University Hospital, Warsaw, Poland
- Department of Ophthalmology, Medical University of Warsaw, Warsaw, Poland
| | - Barbara Bałan
- Department of Immunology Biochemistry and Nutrition, Medical University of Warsaw, Warsaw, Poland
| | | | - Jacek Paweł Szaflik
- SPKSO Ophthalmic University Hospital, Warsaw, Poland
- Department of Ophthalmology, Medical University of Warsaw, Warsaw, Poland
| | | | - Piotr Skopiński
- SPKSO Ophthalmic University Hospital, Warsaw, Poland
- Department of Histology and Embryology, Medical University of Warsaw, Warsaw, Poland
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66
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Calkins DJ. Adaptive responses to neurodegenerative stress in glaucoma. Prog Retin Eye Res 2021; 84:100953. [PMID: 33640464 DOI: 10.1016/j.preteyeres.2021.100953] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/08/2021] [Accepted: 02/19/2021] [Indexed: 12/12/2022]
Abstract
Glaucoma causes loss of vision through degeneration of the retinal ganglion cell (RGC) projection to the brain. The disease is characterized by sensitivity to intraocular pressure (IOP) conveyed at the optic nerve head, through which RGC axons pass unmyelinated to form the optic nerve. From this point, a pathogenic triumvirate comprising inflammatory, oxidative, and metabolic stress influence both proximal structures in the retina and distal structures in the optic projection. This review focuses on metabolic stress and how the optic projection may compensate through novel adaptive mechanisms to protect excitatory signaling to the brain. In the retina and proximal nerve head, the unmyelinated RGC axon segment is energy-inefficient, which leads to increased demand for adenosine-5'-triphosphate (ATP) at the risk of vulnerability to Ca2+-related metabolic and oxidative pressure. This vulnerability may underlie the bidirectional nature of progression. However, recent evidence highlights that the optic projection in glaucoma is not passive but rather demonstrates adaptive processes that may push back against neurodegeneration. In the retina, even as synaptic and dendritic pruning ensues, early progression involves enhanced excitability of RGCs. Enhancement involves depolarization of the resting membrane potential and increased response to light, independent of RGC morphological type. This response is axogenic, arising from increased levels and translocation of voltage-gated sodium channels (NaV) in the unmyelinated segment. During this same early period, large-scale networks of gap-junction coupled astrocytes redistribute metabolic resources to the optic projection stressed by elevated IOP to slow loss of axon function. This redistribution may reflect more local remodeling, as astrocyte processes respond to focal metabolic duress by boosting glycogen turnover in response to axonal activity in an effort to promote survival of the healthiest axons. Both enhanced excitability and metabolic redistribution are transient, indicating that the same adaptive mechanisms that apparently serve to slow progression ultimately may be too expensive for the system to sustain over longer periods.
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Affiliation(s)
- David J Calkins
- The Vanderbilt Eye Institute, Nashville, TN, USA; Vanderbilt Vision Research Center, Vanderbilt University Medical Center, 1161 21st Ave S, AA7100 Medical Center North Nashville, Tennessee, 37232, USA.
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67
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Aydın R, Barış M, Durmaz-Engin C, Al-Aswad LA, Blumberg DM, Cioffi GA, Liebmann JM, Tezel TH, Tezel G. Early localized alterations of the retinal inner plexiform layer in association with visual field worsening in glaucoma patients. PLoS One 2021; 16:e0247401. [PMID: 33630899 PMCID: PMC7906339 DOI: 10.1371/journal.pone.0247401] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 02/06/2021] [Indexed: 01/16/2023] Open
Abstract
Glaucoma is a chronic neurodegenerative disease of the optic nerve and a leading cause of irreversible blindness, worldwide. While the experimental research using animal models provides growing information about cellular and molecular processes, parallel analysis of the clinical presentation of glaucoma accelerates the translational progress towards improved understanding, treatment, and clinical testing of glaucoma. Optic nerve axon injury triggers early alterations of retinal ganglion cell (RGC) synapses with function deficits prior to manifest RGC loss in animal models of glaucoma. For testing the clinical relevance of experimental observations, this study analyzed the functional correlation of localized alterations in the inner plexiform layer (IPL), where RGCs establish synaptic connections with retinal bipolar and amacrine cells. Participants of the study included a retrospective cohort of 36 eyes with glaucoma and a control group of 18 non-glaucomatous subjects followed for two-years. The IPL was analyzed on consecutively collected macular SD-OCT scans, and functional correlations with corresponding 10–2 visual field scores were tested using generalized estimating equations (GEE) models. The GEE-estimated rate of decrease in IPL thickness (R = 0.36, P<0.001) and IPL density (R = 0.36, P<0.001), as opposed to unchanged or increased IPL thickness or density, was significantly associated with visual field worsening at corresponding analysis locations. Based on multivariate logistic regression analysis, this association was independent from the patients’ age, the baseline visual field scores, or the baseline thickness or alterations of retinal nerve fiber or RGC layers (P>0.05). These findings support early localized IPL alterations in correlation with progressing visual field defects in glaucomatous eyes. Considering the experimental data, glaucoma-related increase in IPL thickness/density might reflect dendritic remodeling, mitochondrial redistribution, and glial responses for synapse maintenance, but decreased IPL thickness/density might correspond to dendrite atrophy. The bridging of experimental data with clinical findings encourages further research along the translational path.
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Affiliation(s)
- Rukiye Aydın
- Department of Ophthalmology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States of America
| | - Mine Barış
- Department of Ophthalmology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States of America
| | - Ceren Durmaz-Engin
- Department of Ophthalmology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States of America
| | - Lama A. Al-Aswad
- Department of Ophthalmology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States of America
| | - Dana M. Blumberg
- Department of Ophthalmology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States of America
| | - George A. Cioffi
- Department of Ophthalmology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States of America
| | - Jeffrey M. Liebmann
- Department of Ophthalmology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States of America
| | - Tongalp H. Tezel
- Department of Ophthalmology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States of America
| | - Gülgün Tezel
- Department of Ophthalmology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States of America
- * E-mail:
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Kimball E, Schaub J, Quillen S, Keuthan C, Pease ME, Korneva A, Quigley H. The role of aquaporin-4 in optic nerve head astrocytes in experimental glaucoma. PLoS One 2021; 16:e0244123. [PMID: 33529207 PMCID: PMC7853498 DOI: 10.1371/journal.pone.0244123] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/11/2021] [Indexed: 02/04/2023] Open
Abstract
PURPOSE To study aquaporin channel expression in astrocytes of the mouse optic nerve (ON) and the response to IOP elevation in mice lacking aquaporin 4 (AQP4 null). METHODS C57BL/6 (B6) and AQP4 null mice were exposed to bead-induced IOP elevation for 3 days (3D-IOP), 1 and 6 weeks. Mouse ocular tissue sections were immunolabeled against aquaporins 1(AQP1), 4(AQP4), and 9(AQP9). Ocular tissue was imaged to identify normal AQP distribution, ON changes, and axon loss after IOP elevation. Ultrastructure examination, cell proliferation, gene expression, and transport block were also analyzed. RESULTS B6 mice had abundant AQP4 expression in Müller cells, astrocytes of retina and myelinated ON (MON), but minimal AQP4in prelaminar and unmyelinated ON (UON). MON of AQP4 nulls had smaller ON area, smaller axon diameter, higher axon density, and larger proportionate axon area than B6 (all p≤0.05). Bead-injection led to comparable 3D-IOP elevation (p = 0.42) and axonal transport blockade in both strains. In B6, AQP4 distribution was unchanged after 3D-IOP. At baseline, AQP1 and AQP9 were present in retina, but not in UON and this was unaffected after IOP elevation in both strains. In 3D-IOP mice, ON astrocytes and microglia proliferated, more in B6 than AQP4 null. After 6 week IOP elevation, axon loss occurred equally in the two mouse types (24.6%, AQP4 null vs. 23.3%, B6). CONCLUSION Lack of AQP4 was neither protective nor detrimental to the effects of IOP elevation. The minimal presence of AQP4 in UON may be a vital aspect of the regionally specific phenotype of astrocytes in the mouse optic nerve head.
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Affiliation(s)
- Elizabeth Kimball
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Julie Schaub
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Sarah Quillen
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Casey Keuthan
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Mary Ellen Pease
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Arina Korneva
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Harry Quigley
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
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69
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Hubens WHG, Beckers HJM, Gorgels TGMF, Webers CAB. Increased ratios of complement factors C3a to C3 in aqueous humor and serum mark glaucoma progression. Exp Eye Res 2021; 204:108460. [PMID: 33493474 DOI: 10.1016/j.exer.2021.108460] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/06/2021] [Accepted: 01/18/2021] [Indexed: 12/17/2022]
Abstract
INTRODUCTION We recently performed a combined analysis of publicly available proteomic studies of aqueous humor (AH) of patients with primary open angle glaucoma (POAG). This analysis revealed changes in complement protein concentrations in the AH of progressive POAG patients, which suggested that the complement system may play a role in POAG progression. As the proteomic studies could not provide information on the activity of the complement system, we addressed this question in the current study. METHODS Blood serum and AH were obtained from 30 patients: 10 progressive POAG, 10 stable POAG and, as controls, 10 cataract patients. Glaucoma patients with a visual field Mean Deviation (MD) change of at least 1.0 dB/year were considered progressive; a MD change of less than 0.5 dB/year was considered stable. The ratio between the levels of complement factors C3a and C3 was used as indicator for activation of the complement cascade. The factors were measured with commercially available ELISA kits. RESULTS AH levels of complement factors C3 and C3a did not significantly differ between groups. In serum, complement factor C3 did not differ between groups whereas C3a was significantly elevated in progressive POAG patients compared to controls (p < 0.05). The resulting complement C3a/C3 ratio was significantly higher in progressive POAG patients in both AH (p < 0.05) and serum (p < 0.01), and this ratio significantly correlated between the two body fluids (p < 0.001). Furthermore, there was a strong correlation between disease progression and C3a/C3 activation ratio both in AH (p < 0.01) and in serum (p < 0.001). The higher the complement C3a/C3 ratio, the faster the disease progression. CONCLUSION Significant increases in AH and serum complement C3a/C3 ratios were observed in progressive POAG patients but not in stable POAG patients. Furthermore, the complement C3a/C3 ratio correlated strongly with the rate of disease progression in both AH and serum. These findings suggest that activation of the complement system plays a role in glaucoma progression and that progressive glaucoma patients may have systemic changes in complement activation.
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Affiliation(s)
- W H G Hubens
- University Eye Clinic Maastricht, Maastricht Medical Center, Maastricht, the Netherlands; Research School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - H J M Beckers
- University Eye Clinic Maastricht, Maastricht Medical Center, Maastricht, the Netherlands
| | - T G M F Gorgels
- University Eye Clinic Maastricht, Maastricht Medical Center, Maastricht, the Netherlands
| | - C A B Webers
- University Eye Clinic Maastricht, Maastricht Medical Center, Maastricht, the Netherlands
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70
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Tribble JR, Otmani A, Kokkali E, Lardner E, Morgan JE, Williams PA. Retinal Ganglion Cell Degeneration in a Rat Magnetic Bead Model of Ocular Hypertensive Glaucoma. Transl Vis Sci Technol 2021; 10:21. [PMID: 33510960 PMCID: PMC7804499 DOI: 10.1167/tvst.10.1.21] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 12/02/2020] [Indexed: 01/22/2023] Open
Abstract
Purpose Glaucoma remains a leading cause of irreversible blindness worldwide. Animal glaucoma models replicate high intraocular pressure, a risk factor for glaucoma, to induce retinal ganglion cell (RGC) degeneration. We describe an inducible, magnetic bead model in the Brown Norway rat in which we are able to determine degeneration across multiple RGC compartments at a time point that is appropriate for investigating neurodegenerative events and potential treatment effects. Methods We induced ocular hypertension through injection of magnetic microspheres into the anterior chamber of Brown Norway rats; un-operated (naïve) rats served as controls. Intraocular pressure was recorded, and eye diameter measurements were taken before surgery and at the terminal end points. We assessed RGC degeneration and vascular changes through immunofluorescence, and axon transport to terminal brain thalami through intravitreal injection of fluorophore-conjugated cholera toxin subunit β. Results We observed clinically relevant features of disease accompanying RGC cell somal, axonal, and dendritic loss. RGC axonal dysfunction persisted along the trajectory of the cell into the terminal brain thalami, with clear disruption at the optic nerve head. We also observed vascular compromise consistent with human disease, as well as an expansion of global eye size with ocular hypertension. Conclusions The magnetic bead model in the Brown Norway rat recapitulates many clinically relevant disease features of human glaucoma, including degeneration across multiple RGC compartments. Eye expansion is likely a result of rodent scleral elasticity, and we caution that this should be considered when assessing retinal density measurements. Translational Relevance This model offers a disease-relevant platform that will allow for assessment of glaucoma-relevant therapeutics.
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Affiliation(s)
- James R Tribble
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Amin Otmani
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Eirini Kokkali
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, UK
| | - Emma Lardner
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - James E Morgan
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, UK.,School of Medicine, Cardiff University, Cardiff, Wales, UK
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
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Morgan BP, Gommerman JL, Ramaglia V. An "Outside-In" and "Inside-Out" Consideration of Complement in the Multiple Sclerosis Brain: Lessons From Development and Neurodegenerative Diseases. Front Cell Neurosci 2021; 14:600656. [PMID: 33488361 PMCID: PMC7817777 DOI: 10.3389/fncel.2020.600656] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
The last 15 years have seen an explosion of new findings on the role of complement, a major arm of the immune system, in the central nervous system (CNS) compartment including contributions to cell migration, elimination of synapse during development, aberrant synapse pruning in neurologic disorders, damage to nerve cells in autoimmune diseases, and traumatic injury. Activation of the complement system in multiple sclerosis (MS) is typically thought to occur as part of a primary (auto)immune response from the periphery (the outside) against CNS antigens (the inside). However, evidence of local complement production from CNS-resident cells, intracellular complement functions, and the more recently discovered role of early complement components in shaping synaptic circuits in the absence of inflammation opens up the possibility that complement-related sequelae may start and finish within the brain itself. In this review, the complement system will be introduced, followed by evidence that implicates complement in shaping the developing, adult, and normal aging CNS as well as its contribution to pathology in neurodegenerative conditions. Discussion of data supporting "outside-in" vs. "inside-out" roles of complement in MS will be presented, concluded by thoughts on potential approaches to therapies targeting specific elements of the complement system.
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Affiliation(s)
- B. Paul Morgan
- UK Dementia Research Institute at Cardiff, Cardiff University, Cardiff, United Kingdom
| | | | - Valeria Ramaglia
- Department of Immunology, University of Toronto, Toronto, ON, Canada
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Tribble JR, Kokkali E, Otmani A, Plastino F, Lardner E, Vohra R, Kolko M, André H, Morgan JE, Williams PA. When Is a Control Not a Control? Reactive Microglia Occur Throughout the Control Contralateral Pathway of Retinal Ganglion Cell Projections in Experimental Glaucoma. Transl Vis Sci Technol 2021; 10:22. [PMID: 33510961 PMCID: PMC7804521 DOI: 10.1167/tvst.10.1.22] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 12/02/2020] [Indexed: 12/19/2022] Open
Abstract
Purpose Animal models show retinal ganglion cell (RGC) injuries that replicate features of glaucoma and the contralateral eye is commonly used as an internal control. There is significant crossover of RGC axons from the ipsilateral to the contralateral side at the level of the optic chiasm, which may confound findings when damage is restricted to one eye. The effect of unilateral glaucoma on neuroinflammatory damage to the contralateral pathway of RGC projections has largely been unexplored. Methods Ocular hypertensive glaucoma was induced unilaterally or bilaterally in the rat and RGC neurodegenerative events were assessed. Neuroinflammation was quantified in the retina, optic nerve head, optic nerve, lateral geniculate nucleus, and superior colliculus by high-resolution imaging, and in the retina by flow cytometry and protein arrays. Results After ocular hypertensive stress, peripheral monocytes enter the retina and microglia become reactive. This effect is more marked in animals with bilateral ocular hypertensive glaucoma. In rats where glaucoma was induced unilaterally, there was significant microglia activation in the contralateral (control) eye. Microglial activation extended into the optic nerve and terminal visual thalami, where it was similar across hemispheres in unilateral ocular hypertension. Conclusions These data suggest that caution is warranted when using the contralateral eye as a control and in comparing visual thalami in unilateral models of glaucoma. Translational Relevance The use of a contralateral eye as a control may confound the discovery of human-relevant mechanism and treatments in animal models. We also identify neuroinflammatory protein responses that warrant further investigation as potential disease-modifiable targets.
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Affiliation(s)
- James R. Tribble
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Eirini Kokkali
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, UK
| | - Amin Otmani
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Flavia Plastino
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Emma Lardner
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Rupali Vohra
- Department of Veterinary and Animal Sciences, Pathobiological Sciences, University of Copenhagen, Denmark
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Miriam Kolko
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- Department of Ophthalmology, Rigshospitalet-Glostrup, Copenhagen, Denmark
| | - Helder André
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - James E. Morgan
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, UK
- School of Medicine, Cardiff University, Cardiff, Wales, UK
| | - Pete A. Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
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Bevan RJ, Hughes TR, Williams PA, Good MA, Morgan BP, Morgan JE. Retinal ganglion cell degeneration correlates with hippocampal spine loss in experimental Alzheimer's disease. Acta Neuropathol Commun 2020; 8:216. [PMID: 33287900 PMCID: PMC7720390 DOI: 10.1186/s40478-020-01094-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 11/23/2020] [Indexed: 02/06/2023] Open
Abstract
Neuronal dendritic and synaptic pruning are early features of neurodegenerative diseases, including Alzheimer’s disease. In addition to brain pathology, amyloid plaque deposition, microglial activation, and cell loss occur in the retinas of human patients and animal models of Alzheimer’s disease. Retinal ganglion cells, the output neurons of the retina, are vulnerable to damage in neurodegenerative diseases and are a potential opportunity for non-invasive clinical diagnosis and monitoring of Alzheimer’s progression. However, the extent of retinal involvement in Alzheimer’s models and how well this reflects brain pathology is unclear. Here we have quantified changes in retinal ganglion cells dendritic structure and hippocampal dendritic spines in three well-studied Alzheimer’s mouse models, Tg2576, 3xTg-AD and APPNL-G-F. Dendritic complexity of DiOlistically labelled retinal ganglion cells from retinal explants was reduced in all three models in an age-, gender-, and receptive field-dependent manner. DiOlistically labelled hippocampal slices showed spine loss in CA1 apical dendrites in all three Alzheimer’s models, mirroring the early stages of neurodegeneration as seen in the retina. Morphological classification showed that loss of thin spines predominated in all. The demonstration that retinal ganglion cells dendritic field reduction occurs in parallel with hippocampal dendritic spine loss in all three Alzheimer’s models provide compelling support for the use of retinal neurodegeneration. As retinal dendritic changes are within the optical range of current clinical imaging systems (for example optical coherence tomography), our study makes a case for imaging the retina as a non-invasive way to diagnose disease and monitor progression in Alzheimer’s disease.
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74
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Györffy BA, Tóth V, Török G, Gulyássy P, Kovács RÁ, Vadászi H, Micsonai A, Tóth ME, Sántha M, Homolya L, Drahos L, Juhász G, Kékesi KA, Kardos J. Synaptic mitochondrial dysfunction and septin accumulation are linked to complement-mediated synapse loss in an Alzheimer's disease animal model. Cell Mol Life Sci 2020; 77:5243-5258. [PMID: 32034429 PMCID: PMC7671981 DOI: 10.1007/s00018-020-03468-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 12/25/2019] [Accepted: 01/21/2020] [Indexed: 12/21/2022]
Abstract
Synaptic functional disturbances with concomitant synapse loss represent central pathological hallmarks of Alzheimer's disease. Excessive accumulation of cytotoxic amyloid oligomers is widely recognized as a key event that underlies neurodegeneration. Certain complement components are crucial instruments of widespread synapse loss because they can tag synapses with functional impairments leading to their engulfment by microglia. However, an exact understanding of the affected synaptic functions that predispose to complement-mediated synapse elimination is lacking. Therefore, we conducted systematic proteomic examinations on synaptosomes prepared from an amyloidogenic mouse model of Alzheimer's disease (APP/PS1). Synaptic fractions were separated according to the presence of the C1q-tag using fluorescence-activated synaptosome sorting and subjected to proteomic comparisons. The results raised the decline of mitochondrial functions in the C1q-tagged synapses of APP/PS1 mice based on enrichment analyses, which was verified using flow cytometry. Additionally, proteomics results revealed extensive alterations in the level of septin protein family members, which are known to dynamically form highly organized pre- and postsynaptic supramolecular structures, thereby affecting synaptic transmission. High-resolution microscopy investigations demonstrated that synapses with considerable amounts of septin-3 and septin-5 show increased accumulation of C1q in APP/PS1 mice compared to the wild-type ones. Moreover, a strong positive correlation was apparent between synaptic septin-3 levels and C1q deposition as revealed via flow cytometry and confocal microscopy examinations. In sum, our results imply that deterioration of synaptic mitochondrial functions and alterations in the organization of synaptic septins are associated with complement-dependent synapse loss in Alzheimer's disease.
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Affiliation(s)
- Balázs A Györffy
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
- Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Vilmos Tóth
- Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
- Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - György Török
- Molecular Cell Biology Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Péter Gulyássy
- MS Proteomics Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Budapest, Hungary
| | - Réka Á Kovács
- Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Henrietta Vadászi
- Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - András Micsonai
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
- Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Melinda E Tóth
- Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - Miklós Sántha
- Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - László Homolya
- Molecular Cell Biology Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary
| | - László Drahos
- MS Proteomics Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Budapest, Hungary
| | - Gábor Juhász
- Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
- CRU Hungary Ltd., Göd, Hungary
| | - Katalin A Kékesi
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
- Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
- Department of Physiology and Neurobiology, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - József Kardos
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.
- Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.
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75
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Harder JM, Williams PA, Braine CE, Yang HS, Thomas JM, Foxworth NE, John SWM, Howell GR. Complement peptide C3a receptor 1 promotes optic nerve degeneration in DBA/2J mice. J Neuroinflammation 2020; 17:336. [PMID: 33176797 PMCID: PMC7656757 DOI: 10.1186/s12974-020-02011-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/28/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The risk of glaucoma increases significantly with age and exposure to elevated intraocular pressure, two factors linked with neuroinflammation. The complement cascade is a complex immune process with many bioactive end-products, including mediators of inflammation. Complement cascade activation has been shown in glaucoma patients and models of glaucoma. However, the function of complement-mediated inflammation in glaucoma is largely untested. Here, the complement peptide C3a receptor 1 was genetically disrupted in DBA/2J mice, an ocular hypertensive model of glaucoma, to test its contribution to neurodegeneration. METHODS A null allele of C3ar1 was backcrossed into DBA/2J mice. Development of iris disease, ocular hypertension, optic nerve degeneration, retinal ganglion cell activity, loss of RGCs, and myeloid cell infiltration in C3ar1-deficient and sufficient DBA/2J mice were compared across multiple ages. RNA sequencing was performed on microglia from primary culture to determine global effects of C3ar1 on microglia gene expression. RESULTS Deficiency in C3ar1 lowered the risk of degeneration in ocular hypertensive mice without affecting intraocular pressure elevation at 10.5 months of age. Differences were found in the percentage of mice affected, but not in individual characteristics of disease progression. The protective effect of C3ar1 deficiency was then overcome by additional aging and ocular hypertensive injury. Microglia and other myeloid-derived cells were the primary cells identified that express C3ar1. In the absence of C3ar1, microglial expression of genes associated with neuroinflammation and other immune functions were differentially expressed compared to WT. A network analysis of these data suggested that the IL10 signaling pathway is a major interaction partner of C3AR1 signaling in microglia. CONCLUSIONS C3AR1 was identified as a damaging neuroinflammatory factor. These data help suggest complement activation causes glaucomatous neurodegeneration through multiple mechanisms, including inflammation. Microglia and infiltrating myeloid cells expressed high levels of C3ar1 and are the primary candidates to mediate its effects. C3AR1 appeared to be a major regulator of microglia reactivity and neuroinflammatory function due to its interaction with IL10 signaling and other immune related pathways. Targeting myeloid-derived cells and C3AR1 signaling with therapies is expected to add to or improve neuroprotective therapeutic strategies.
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Affiliation(s)
| | - Pete A Williams
- The Jackson Laboratory, Bar Harbor, ME, USA
- Division of Eye and Vision, Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Catherine E Braine
- The Jackson Laboratory, Bar Harbor, ME, USA
- Zuckerman Mind Brain Behavior Institute, New York, NY, USA
| | | | | | | | - Simon W M John
- The Jackson Laboratory, Bar Harbor, ME, USA.
- Department of Ophthalmology, Tufts University of Medicine, Boston, MA, USA.
- Howard Hughes Medical Institute, Department of Ophthalmology, Columbia University Medical Center, and Zuckerman Mind Brain Behavior Institute, New York, NY, USA.
| | - Gareth R Howell
- The Jackson Laboratory, Bar Harbor, ME, USA.
- Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA.
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA.
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76
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Sterling JK, Adetunji MO, Guttha S, Bargoud AR, Uyhazi KE, Ross AG, Dunaief JL, Cui QN. GLP-1 Receptor Agonist NLY01 Reduces Retinal Inflammation and Neuron Death Secondary to Ocular Hypertension. Cell Rep 2020; 33:108271. [PMID: 33147455 PMCID: PMC7660987 DOI: 10.1016/j.celrep.2020.108271] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 08/03/2020] [Accepted: 09/23/2020] [Indexed: 12/16/2022] Open
Abstract
Glaucoma is the leading cause of irreversible blindness and is characterized by the death of retinal ganglion cells (RGCs). Recent studies have implicated pro-inflammatory microglia, macrophages, and A1 astrocytes in the pathogenesis of neurodegenerative diseases. The role of pro-inflammatory, neurotoxic A1 astrocytes in glaucoma is just beginning to be explored. Using a mouse model of glaucoma, we demonstrate that ocular hypertension is sufficient to trigger production of C1q, interleukin-1α (IL-1α), and tumor necrosis factor α (TNF-α), three cytokines necessary and sufficient to drive the formation of A1 astrocytes. Upregulation of these cytokines occurs first in CD11b+ CD11c+ cells followed by CD11b+ CD11c- cells. Ablation of this pathway, by either genetic deletions of C1qa, IL-1α, and TNF-α, or treatment with glucagon-like peptide-1 receptor agonist NLY01, reduces A1 astrocyte transformation and RGC death. Together, these results highlight a neuroinflammatory mechanism of glaucomatous neurodegeneration that can be therapeutically targeted by NLY01 administration.
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Affiliation(s)
- Jacob K Sterling
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Medical Scientist Training Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Modupe O Adetunji
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Samyuktha Guttha
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Albert R Bargoud
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Katherine E Uyhazi
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Ahmara G Ross
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Joshua L Dunaief
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Qi N Cui
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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77
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Oikawa K, Teixeira LBC, Keikhosravi A, Eliceiri KW, McLellan GJ. Microstructure and resident cell-types of the feline optic nerve head resemble that of humans. Exp Eye Res 2020; 202:108315. [PMID: 33091431 DOI: 10.1016/j.exer.2020.108315] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/09/2020] [Accepted: 10/16/2020] [Indexed: 01/15/2023]
Abstract
The lamina cribrosa (LC) region of the optic nerve head (ONH) is considered a primary site for glaucomatous damage. In humans, biology of this region reflects complex interactions between retinal ganglion cell (RGC) axons and other resident ONH cell-types including astrocytes, lamina cribrosa cells, microglia and oligodendrocytes, as well as ONH microvasculature and collagenous LC beams. However, species differences in the microanatomy of this region could profoundly impact efforts to model glaucoma pathobiology in a research setting. In this study, we characterized resident cell-types, ECM composition and ultrastructure in relation to microanatomy of the ONH in adult domestic cats (Felis catus). Longitudinal and transverse cryosections of ONH tissues were immunolabeled with astrocyte, microglia/macrophage, oligodendrocyte, LC cell and vascular endothelial cell markers. Collagen fiber structure of the LC was visualized by second harmonic generation (SHG) with multiphoton microscopy. Fibrous astrocytes form glial fibrillary acidic protein (GFAP)-positive glial columns in the pre-laminar region, and cover the collagenous plates of the LC region in lamellae oriented perpendicular to the axons. GFAP-negative and alpha-smooth muscle actin-positive LC cells were identified in the feline ONH. IBA-1 positive immune cells and von Willebrand factor-positive blood vessel endothelial cells are also identifiable throughout the feline ONH. As in humans, myelination commences with a population of oligodendrocytes in the retro-laminar region of the feline ONH. Transmission electron microscopy confirmed the presence of capillaries and LC cells that extend thin processes in the core of the collagenous LC beams. In conclusion, the feline ONH closely recapitulates the complexity of the ONH of humans and non-human primates, with diverse ONH cell-types and a robust collagenous LC, within the beams of which, LC cells and capillaries reside. Thus, studies in a feline inherited glaucoma model have the potential to play a key role in enhancing our understanding of ONH cellular and molecular processes in glaucomatous optic neuropathy.
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Affiliation(s)
- Kazuya Oikawa
- Ophthalmology & Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA; Surgical Sciences, University of Wisconsin-Madison, WI, USA; McPherson Eye Research Institute, Madison, WI, USA
| | - Leandro B C Teixeira
- McPherson Eye Research Institute, Madison, WI, USA; Pathobiological Sciences, University of Wisconsin-Madison, WI, USA
| | - Adib Keikhosravi
- Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Kevin W Eliceiri
- McPherson Eye Research Institute, Madison, WI, USA; Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Gillian J McLellan
- Ophthalmology & Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA; Surgical Sciences, University of Wisconsin-Madison, WI, USA; McPherson Eye Research Institute, Madison, WI, USA.
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78
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Baudouin C, Kolko M, Melik-Parsadaniantz S, Messmer EM. Inflammation in Glaucoma: From the back to the front of the eye, and beyond. Prog Retin Eye Res 2020; 83:100916. [PMID: 33075485 DOI: 10.1016/j.preteyeres.2020.100916] [Citation(s) in RCA: 182] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 10/09/2020] [Accepted: 10/13/2020] [Indexed: 02/08/2023]
Abstract
The pathophysiology of glaucoma is complex, multifactorial and not completely understood. Elevated intraocular pressure (IOP) and/or impaired retinal blood flow may cause initial optic nerve damage. In addition, age-related oxidative stress in the retina concurrently with chronic mechanical and vascular stress is crucial for the initiation of retinal neurodegeneration. Oxidative stress is closely related to cell senescence, mitochondrial dysfunction, excitotoxicity, and neuroinflammation, which are involved in glaucoma progression. Accumulating evidence from animal glaucoma models and from human ocular samples suggests a dysfunction of the para-inflammation in the retinal ganglion cell layer and the optic nerve head. Moreover, quite similar mechanisms in the anterior chamber could explain the trabecular meshwork dysfunction and the elevated IOP in primary open-angle glaucoma. On the other hand, ocular surface disease due to topical interventions is the most prominent and visible consequence of inflammation in glaucoma, with a negative impact on filtering surgery failure, topical treatment efficacy, and possibly on inflammation in the anterior segment. Consequently, glaucoma appears as an outstanding eye disease where inflammatory changes may be present to various extents and consequences along the eye structure, from the ocular surface to the posterior segment, and the visual pathway. Here we reviewed the inflammatory processes in all ocular structures in glaucoma from the back to the front of the eye and beyond. Our approach was to explain how para-inflammation is necessary to maintain homoeostasis, and to describe abnormal inflammatory findings observed in glaucomatous patients or in animal glaucoma models, supporting the hypothesis of a dysregulation of the inflammatory balance toward a pro-inflammatory phenotype. Possible anti-inflammatory therapeutic approaches in glaucoma are also discussed.
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Affiliation(s)
- Christophe Baudouin
- Quinze-Vingts National Ophthalmology Hospital, INSERM-DGOS CIC 1423, IHU Foresight, Paris, France; Sorbonne Université, INSERM, CNRS, Institut de La Vision, Paris, France; Department of Ophthalmology, Ambroise Paré Hospital, APHP, Université de Versailles Saint-Quentin en Yvelines, Boulogne-Billancourt, France.
| | - Miriam Kolko
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark; Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet-Glostrup, Glostrup, Denmark
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Jiao H, Provis JM, Natoli R, Rutar M. Ablation of C3 modulates macrophage reactivity in the outer retina during photo-oxidative damage. Mol Vis 2020; 26:679-690. [PMID: 33088172 PMCID: PMC7553722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 10/08/2020] [Indexed: 11/14/2022] Open
Abstract
Purpose Dysregulation of the complement cascade contributes to a variety of retinal dystrophies, including age-related macular degeneration (AMD). The central component of complement, C3, is expressed in abundance by macrophages in the outer retina, and its ablation suppresses photoreceptor death in experimental photo-oxidative damage. Whether this also influences macrophage reactivity in this model system, however, is unknown. We investigate the effect of C3 ablation on macrophage activity and phagocytosis by outer retinal macrophages during photo-oxidative damage. Methods Age-matched C3 knockout (KO) mice and wild-type (WT) C57/Bl6 mice were subjected to photo-oxidative damage. Measurements of the outer nuclear layer (ONL) thickness and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were used to assess pathology and photoreceptor apoptosis, respectively. Macrophage abundance and phagocytosis were assessed with immunolabeling for pan-macrophage and phagocytic markers, in conjunction with TUNEL staining in cohorts of C3 KO and WT mice. Results The C3 KO mice exhibited protection against photoreceptor cell death following photo-oxidative damage, which was associated with a reduction in immunoreactivity for the stress-related factor GFAP. In conjunction, there was a reduction in IBA1-positive macrophages in the outer retina compared to the WT mice and a decrease in the number of CD68-positive cells in the outer nuclear layer and the subretinal space. In addition, the engulfment of TUNEL-positive and -negative photoreceptors by macrophages was significantly lower in the C3 KO mice cohort following photo-oxidative damage compared to the WT cohort. Conclusions The results show that the absence of C3 mitigates the phagocytosis of photoreceptors by macrophages in the outer retina, and the net impact of C3 depletion is neuroprotective in the context of photo-oxidative damage. These data improve our understanding of the impact of C3 inhibition in subretinal inflammation and inform the development of treatments for targeting complement activation in diseases such as AMD.
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Affiliation(s)
- Haihan Jiao
- Department of Optometry and Vision Science, University of Melbourne, Victoria, Australia,The John Curtin School of Medical Research, The Australian National University, Acton, Australia
| | - Jan M. Provis
- The John Curtin School of Medical Research, The Australian National University, Acton, Australia,The Australian National University Medical School, Acton, Australia
| | - Riccardo Natoli
- The John Curtin School of Medical Research, The Australian National University, Acton, Australia,The Australian National University Medical School, Acton, Australia
| | - Matt Rutar
- Department of Anatomy and Neuroscience, University of Melbourne, Victoria, Australia
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80
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Borucki DM, Toutonji A, Couch C, Mallah K, Rohrer B, Tomlinson S. Complement-Mediated Microglial Phagocytosis and Pathological Changes in the Development and Degeneration of the Visual System. Front Immunol 2020; 11:566892. [PMID: 33072106 PMCID: PMC7541817 DOI: 10.3389/fimmu.2020.566892] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/17/2020] [Indexed: 12/21/2022] Open
Abstract
The focus of this review is the role of complement-mediated phagocytosis in retinal and neurological diseases affecting the visual system. Complement activation products opsonize synaptic material on neurons for phagocytic removal, which is a normal physiological process during development, but a pathological process in several neurodegenerative diseases and conditions. We discuss the role of complement in the refinement and elimination of synapses in the retina and lateral geniculate nucleus, both during development and in disease states. How complement and aberrant phagocytosis promotes injury to the visual system is discussed primarily in the context of multiple sclerosis, where it has been extensively studied, although the role of complement in visual dysfunction in other diseases such as stroke and traumatic brain injury is also highlighted. Retinal diseases are also covered, with a focus on glaucoma and age-related macular degeneration. Finally, we discuss the potential of complement inhibitory strategies to treat diseases affecting the visual system.
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Affiliation(s)
- Davis M. Borucki
- Medical Scientist Training Program, Medical University of South Carolina, Charleston, SC, United States
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, United States
| | - Amer Toutonji
- Medical Scientist Training Program, Medical University of South Carolina, Charleston, SC, United States
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, United States
| | - Christine Couch
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
| | - Khalil Mallah
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
| | - Baerbel Rohrer
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, United States
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC, United States
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States
| | - Stephen Tomlinson
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States
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Cimaglia G, Votruba M, Morgan JE, André H, Williams PA. Potential Therapeutic Benefit of NAD + Supplementation for Glaucoma and Age-Related Macular Degeneration. Nutrients 2020; 12:nu12092871. [PMID: 32961812 PMCID: PMC7551676 DOI: 10.3390/nu12092871] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/14/2020] [Accepted: 09/17/2020] [Indexed: 12/13/2022] Open
Abstract
Glaucoma and age-related macular degeneration are leading causes of irreversible blindness worldwide with significant health and societal burdens. To date, no clinical cures are available and treatments target only the manageable symptoms and risk factors (but do not remediate the underlying pathology of the disease). Both diseases are neurodegenerative in their pathology of the retina and as such many of the events that trigger cell dysfunction, degeneration, and eventual loss are due to mitochondrial dysfunction, inflammation, and oxidative stress. Here, we critically review how a decreased bioavailability of nicotinamide adenine dinucleotide (NAD; a crucial metabolite in healthy and disease states) may underpin many of these aberrant mechanisms. We propose how exogenous sources of NAD may become a therapeutic standard for the treatment of these conditions.
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Affiliation(s)
- Gloria Cimaglia
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 112 82 Stockholm, Sweden;
- School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4HQ, Wales, UK; (M.V.); (J.E.M.)
| | - Marcela Votruba
- School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4HQ, Wales, UK; (M.V.); (J.E.M.)
- Cardiff Eye Unit, University Hospital Wales, Cardiff CF14 4XW, Wales, UK
| | - James E. Morgan
- School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4HQ, Wales, UK; (M.V.); (J.E.M.)
- School of Medicine, Cardiff University, Cardiff CF14 4YS, Wales, UK
| | - Helder André
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 112 82 Stockholm, Sweden;
- Correspondence: (H.A.); (P.A.W.)
| | - Pete A. Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 112 82 Stockholm, Sweden;
- Correspondence: (H.A.); (P.A.W.)
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Association of imaging biomarkers and local activation of complement in aqueous humor of patients with early forms of age-related macular degeneration. Graefes Arch Clin Exp Ophthalmol 2020; 259:623-632. [PMID: 32876798 PMCID: PMC7904720 DOI: 10.1007/s00417-020-04910-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/17/2020] [Accepted: 08/20/2020] [Indexed: 12/16/2022] Open
Abstract
Purpose To investigate a possible correlation between established imaging biomarkers for age-related macular degeneration and local complement system activation, measured in aqueous humor (AH) of patients with early stages of age-related macular degeneration (AMD) and controls. Methods This analysis included prospectively acquired AH samples of 106 eyes (35 with early/intermediate AMD, 71 controls). The levels of complement protein 3 (C3), 4 (C4), 5 (C5); activation products of complement factor 3a (C3a) and Ba, C3b/iC3b; complement factors B, D, H, I (CFB, CFD, CFH, CFI); and total protein concentration were analyzed. Quantitative levels of complement factors were correlated to the presence of reticular pseudodrusen (RPD), the presence of hyperreflective foci (HRF), and total drusen volume (DV) graded on imaging by spectral-domain optical coherence tomography and using Spearman’s rank correlation test. Results DV correlated with C3b/iC3b (r = 0.285; P = 0.034), C3a (r = 0.200; P = 0.047), Ba (r = 0.262; P = 0.009), and C5 (r = 430; P = 0.005), and showed a tendency towards correlation with C3a (r = 0.198; P = 0.057). HRF correlated significantly with C5 (r = 0.388; P = 0.011) and RPD showed a tendency towards correlation with CFB (r = 0.196; P = 0.050). Conclusion In patients with early AMD, HRF and drusen parameters but not RPD show low to fair levels of correlation with local complement activation in patients’ AH. Better understanding of complement activation could provide some insights into the pathogenesis of AMD. Imaging biomarkers could be useful to identify suitable patients for future clinical trials with complement-modulating therapies.
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83
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Gupta VB, Chitranshi N, den Haan J, Mirzaei M, You Y, Lim JK, Basavarajappa D, Godinez A, Di Angelantonio S, Sachdev P, Salekdeh GH, Bouwman F, Graham S, Gupta V. Retinal changes in Alzheimer's disease- integrated prospects of imaging, functional and molecular advances. Prog Retin Eye Res 2020; 82:100899. [PMID: 32890742 DOI: 10.1016/j.preteyeres.2020.100899] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 08/24/2020] [Accepted: 08/27/2020] [Indexed: 12/31/2022]
Abstract
Alzheimer's Disease (AD) is a devastating neurodegenerative disorder of the brain, clinically characterised by cognitive deficits that gradually worsen over time. There is, at present, no established cure, or disease-modifying treatments for AD. As life expectancy increases globally, the number of individuals suffering from the disease is projected to increase substantially. Cumulative evidence indicates that AD neuropathological process is initiated several years, if not decades, before clinical signs are evident in patients, and diagnosis made. While several imaging, cognitive, CSF and blood-based biomarkers have been proposed for the early detection of AD; their sensitivity and specificity in the symptomatic stages is highly variable and it is difficult to justify their use in even earlier, pre-clinical stages of the disease. Research has identified potentially measurable functional, structural, metabolic and vascular changes in the retina during early stages of AD. Retina offers a distinctively accessible insight into brain pathology and current and developing ophthalmic technologies have provided us with the possibility of detecting and characterising subtle, disease-related changes. Recent human and animal model studies have further provided mechanistic insights into the biochemical pathways that are altered in the retina in disease, including amyloid and tau deposition. This information coupled with advances in molecular imaging has allowed attempts to monitor biochemical changes and protein aggregation pathology in the retina in AD. This review summarises the existing knowledge that informs our understanding of the impact of AD on the retina and highlights some of the gaps that need to be addressed. Future research will integrate molecular imaging innovation with functional and structural changes to enhance our knowledge of the AD pathophysiological mechanisms and establish the utility of monitoring retinal changes as a potential biomarker for AD.
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Affiliation(s)
- Veer B Gupta
- School of Medicine, Deakin University, VIC, Australia
| | - Nitin Chitranshi
- Faculty of Medicine Health and Human Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Jurre den Haan
- Department of Neurology, Alzheimer Center Amsterdam, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMC, the Netherlands
| | - Mehdi Mirzaei
- Faculty of Medicine Health and Human Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Yuyi You
- Faculty of Medicine Health and Human Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Jeremiah Kh Lim
- Optometry and Vision Science, College of Nursing and Health Sciences, Bedford Park, South Australia, 5042, Australia
| | - Devaraj Basavarajappa
- Faculty of Medicine Health and Human Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Angela Godinez
- Faculty of Medicine Health and Human Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Silvia Di Angelantonio
- Center for Life Nanoscience, Istituto Italiano di Tecnologia, Rome, Italy; Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Perminder Sachdev
- Centre for Healthy Brain and Ageing (CHeBA), School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia; Neuropsychiatric Institute, Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Ghasem H Salekdeh
- Department of Molecular Systems Biology, Cell Science Research Center, Royan, Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Femke Bouwman
- Department of Neurology, Alzheimer Center Amsterdam, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMC, the Netherlands
| | - Stuart Graham
- Faculty of Medicine Health and Human Sciences, Macquarie University, North Ryde, NSW, 2109, Australia; Save Sight Institute, Sydney University, Sydney, NSW, 2000, Australia.
| | - Vivek Gupta
- Faculty of Medicine Health and Human Sciences, Macquarie University, North Ryde, NSW, 2109, Australia.
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84
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Zarantonello A, Presumey J, Simoni L, Yalcin E, Fox R, Hansen A, Olesen HG, Thiel S, Johnson MB, Stevens B, Laursen NS, Carroll MC, Andersen GR. An Ultrahigh-Affinity Complement C4b-Specific Nanobody Inhibits In Vivo Assembly of the Classical Pathway Proconvertase. THE JOURNAL OF IMMUNOLOGY 2020; 205:1678-1694. [PMID: 32769120 DOI: 10.4049/jimmunol.2000528] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/09/2020] [Indexed: 01/07/2023]
Abstract
The classical and lectin pathways of the complement system are important for the elimination of pathogens and apoptotic cells and stimulation of the adaptive immune system. Upon activation of these pathways, complement component C4 is proteolytically cleaved, and the major product C4b is deposited on the activator, enabling assembly of a C3 convertase and downstream alternative pathway amplification. Although excessive activation of the lectin and classical pathways contributes to multiple autoimmune and inflammatory diseases and overexpression of a C4 isoform has recently been linked to schizophrenia, a C4 inhibitor and structural characterization of the convertase formed by C4b is lacking. In this study, we present the nanobody hC4Nb8 that binds with picomolar affinity to human C4b and potently inhibits in vitro complement C3 deposition through the classical and lectin pathways in human serum and in mouse serum. The crystal structure of the C4b:hC4Nb8 complex and a three-dimensional reconstruction of the C4bC2 proconvertase obtained by electron microscopy together rationalize how hC4Nb8 prevents proconvertase assembly through recognition of a neoepitope exposed in C4b and reveals a unique C2 conformation compared with the alternative pathway proconvertase. On human induced pluripotent stem cell-derived neurons, the nanobody prevents C3 deposition through the classical pathway. Furthermore, hC4Nb8 inhibits the classical pathway-mediated immune complex delivery to follicular dendritic cells in vivo. The hC4Nb8 represents a novel ultrahigh-affinity inhibitor of the classical and lectin pathways of the complement cascade under both in vitro and in vivo conditions.
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Affiliation(s)
| | - Jessy Presumey
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Léa Simoni
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Esra Yalcin
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Rachel Fox
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Annette Hansen
- Department of Biomedicine, Aarhus University, DK8000 Aarhus, Denmark
| | - Heidi Gytz Olesen
- Department of Molecular Biology and Genetics, Aarhus University, DK8000 Aarhus, Denmark
| | - Steffen Thiel
- Department of Biomedicine, Aarhus University, DK8000 Aarhus, Denmark
| | - Matthew B Johnson
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142.,Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115
| | - Beth Stevens
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142.,Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115.,Department of Neurology, Harvard Medical School, Boston, MA 02115.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115; and
| | - Nick Stub Laursen
- Department of Molecular Biology and Genetics, Aarhus University, DK8000 Aarhus, Denmark
| | - Michael C Carroll
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115.,Department of Pediatrics, Harvard Medical School, Boston, MA 02115
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, DK8000 Aarhus, Denmark;
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85
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Mongan D, Ramesar M, Föcking M, Cannon M, Cotter D. Role of inflammation in the pathogenesis of schizophrenia: A review of the evidence, proposed mechanisms and implications for treatment. Early Interv Psychiatry 2020; 14:385-397. [PMID: 31368253 DOI: 10.1111/eip.12859] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 05/13/2019] [Accepted: 07/14/2019] [Indexed: 12/28/2022]
Abstract
AIM Over the past several decades, there has been a growing research interest in the role of inflammation in the pathogenesis of schizophrenia. This review aims to summarize evidence in support of this relationship, to discuss biological mechanisms that might explain it, and to explore the translational impact by examining evidence from trials of anti-inflammatory and immunomodulatory agents in the treatment of schizophrenia. METHODS This narrative review of the literature summarizes evidence from observational studies, clinical trials and meta-analyses to evaluate the role of inflammation in the pathogenesis of schizophrenia and to discuss associated implications for treatment. RESULTS Epidemiological evidence and animal models support a hypothesis of maternal immune activation during pregnancy, which increases the risk of schizophrenia in the offspring. Several biomarker studies have found associations between classical pro-inflammatory cytokines and schizophrenia. The precise biological mechanisms by which inflammatory processes might contribute to the pathogenesis of schizophrenia remain unclear, but likely include the actions of microglia and the complement system. Importantly, several trials provide evidence that certain anti-inflammatory and immunomodulatory agents show beneficial effects in the treatment of schizophrenia. Nevertheless, there is a need for further precision-focused basic science and translational research. CONCLUSIONS Increasing our understanding of the role of inflammation in schizophrenia will enable novel opportunities for therapeutic and preventative interventions that are informed by the underlying pathogenesis of this complex disorder.
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Affiliation(s)
- David Mongan
- Royal College of Surgeons in Ireland, Dublin, Ireland
| | | | | | - Mary Cannon
- Royal College of Surgeons in Ireland, Dublin, Ireland
| | - David Cotter
- Royal College of Surgeons in Ireland, Dublin, Ireland
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86
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Gassel CJ, Reinehr S, Gomes SC, Dick HB, Joachim SC. Preservation of optic nerve structure by complement inhibition in experimental glaucoma. Cell Tissue Res 2020; 382:293-306. [PMID: 32676862 PMCID: PMC8285355 DOI: 10.1007/s00441-020-03240-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 06/04/2020] [Indexed: 01/09/2023]
Abstract
Glaucoma is characterized by a progressive damage of the retina and the optic nerve. Despite a huge research interest, the exact pathomechanisms are still unknown. In the experimental autoimmune glaucoma model, rats develop glaucoma-like damage of the retina and the optic nerve after immunization with an optic nerve antigen homogenate (ONA). An early activation of the complement system, even before optic nerve degeneration, was reported in this model. Here, we investigated the effects of a monoclonal antibody against complement factor C5 on optic nerves. Rats were immunized with ONA and compared to controls. In one eye of some ONA animals, the antibody against C5 was intravitreally injected (15 μmol: ONA + C5-I or 25 μmol: ONA + C5-II) before immunization and then every 2 weeks. After 6 weeks, optic nerves were processed for histology (n = 6/group). These analyses demonstrated that the intravitreal therapy reduced the depositions of the membrane attack complex compared to ONA animals (ONA + C5-I: p = 0.005; ONA + C5-II: p = 0.002). Cellular infiltration was significantly reduced in the ONA + C5-I group (p = 0.003), but not in ONA + C5-II tissues (p = 0.41). Furthermore, SMI-32 staining revealed that neurofilament was preserved in both treatment groups compared to ONA optic nerves (both p = 0.002). A decreased amount of microglia was found in treated animals in comparison to the ONA group (ONA + C5-I: p = 0.03; ONA + C5-II: p = 0.009). We observed, for the first time, that a complement system inhibition could prevent optic nerve damage in an autoimmune glaucoma model. Therefore, complement inhibition could serve as a new therapeutic tool for glaucoma.
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Affiliation(s)
- Caroline J Gassel
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany
| | - Sabrina Reinehr
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany
| | - Sara C Gomes
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany
| | - H Burkhard Dick
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany
| | - Stephanie C Joachim
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany.
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87
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Tezel G. A broad perspective on the molecular regulation of retinal ganglion cell degeneration in glaucoma. PROGRESS IN BRAIN RESEARCH 2020; 256:49-77. [PMID: 32958215 DOI: 10.1016/bs.pbr.2020.05.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Glaucoma is a complex neurodegenerative disease involving RGC axons, somas, and synapses at dendrites and axon terminals. Recent research advancements in the field have revealed a bigger picture of glaucomatous neurodegeneration that encompasses multiple stressors, multiple injury sites, multiple cell types, and multiple signaling pathways for asynchronous degeneration of RGCs during a chronic disease period. Optic nerve head is commonly viewed as the critical site of injury in glaucoma, where early injurious insults initiate distal and proximal signaling for axonal and somatic degeneration. Despite compartmentalized processes for degeneration of RGC axons and somas, there are intricate interactions between the two compartments and mechanistic overlaps between the molecular pathways that mediate degeneration in axonal and somatic compartments. This review summarizes the recent progress in the molecular understanding of RGC degeneration in glaucoma and highlights various etiological paths with biomechanical, metabolic, oxidative, and inflammatory components. Through this growing body of knowledge, the glaucoma community moves closer toward causative treatment of this blinding disease.
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Affiliation(s)
- Gülgün Tezel
- Department of Ophthalmology, Vagelos College of Physicians and Surgeons, Columbia University, Edward S. Harkness Eye Institute, New York, NY, United States.
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88
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Bevan RJ, Williams PA, Waters CT, Thirgood R, Mui A, Seto S, Good M, Morgan JE, Votruba M, Erchova I. OPA1 deficiency accelerates hippocampal synaptic remodelling and age-related deficits in learning and memory. Brain Commun 2020; 2:fcaa101. [PMID: 33094281 PMCID: PMC7566495 DOI: 10.1093/braincomms/fcaa101] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 04/09/2020] [Accepted: 05/27/2020] [Indexed: 12/13/2022] Open
Abstract
A healthy mitochondrial network is essential for the maintenance of neuronal synaptic integrity. Mitochondrial and metabolic dysfunction contributes to the pathogenesis of many neurodegenerative diseases including dementia. OPA1 is the master regulator of mitochondrial fusion and fission and is likely to play an important role during neurodegenerative events. To explore this, we quantified hippocampal dendritic and synaptic integrity and the learning and memory performance of aged Opa1 haploinsufficient mice carrying the Opa1Q285X mutation (B6; C3-Opa1Q285STOP ; Opa1+/- ). We demonstrate that heterozygous loss of Opa1 results in premature age-related loss of spines in hippocampal pyramidal CA1 neurons and a reduction in synaptic density in the hippocampus. This loss is associated with subtle memory deficits in both spatial novelty and object recognition. We hypothesize that metabolic failure to maintain normal neuronal activity at the level of a single spine leads to premature age-related memory deficits. These results highlight the importance of mitochondrial homeostasis for maintenance of neuronal function during ageing.
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Affiliation(s)
- Ryan J Bevan
- School of Optometry and Vision Sciences, Cardiff University, Maindy Rd, Cardiff, CF24 4HQ, UK
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Polhemsgatan 50, 112 82 Stockholm, Sweden
| | - Caroline T Waters
- School of Optometry and Vision Sciences, Cardiff University, Maindy Rd, Cardiff, CF24 4HQ, UK
| | - Rebecca Thirgood
- School of Optometry and Vision Sciences, Cardiff University, Maindy Rd, Cardiff, CF24 4HQ, UK
| | - Amanda Mui
- School of Optometry and Vision Sciences, Cardiff University, Maindy Rd, Cardiff, CF24 4HQ, UK
| | - Sharon Seto
- School of Optometry and Vision Sciences, Cardiff University, Maindy Rd, Cardiff, CF24 4HQ, UK
| | - Mark Good
- School of Psychology, Cardiff University, Tower Building, 70 Park Place, Cardiff, CF10 3AT, UK
| | - James E Morgan
- School of Optometry and Vision Sciences, Cardiff University, Maindy Rd, Cardiff, CF24 4HQ, UK
| | - Marcela Votruba
- School of Optometry and Vision Sciences, Cardiff University, Maindy Rd, Cardiff, CF24 4HQ, UK
| | - Irina Erchova
- School of Optometry and Vision Sciences, Cardiff University, Maindy Rd, Cardiff, CF24 4HQ, UK
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89
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Yin Y, De Lima S, Gilbert HY, Hanovice NJ, Peterson SL, Sand RM, Sergeeva EG, Wong KA, Xie L, Benowitz LI. Optic nerve regeneration: A long view. Restor Neurol Neurosci 2020; 37:525-544. [PMID: 31609715 DOI: 10.3233/rnn-190960] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The optic nerve conveys information about the outside world from the retina to multiple subcortical relay centers. Until recently, the optic nerve was widely believed to be incapable of re-growing if injured, with dire consequences for victims of traumatic, ischemic, or neurodegenerative diseases of this pathway. Over the past 10-20 years, research from our lab and others has made considerable progress in defining factors that normally suppress axon regeneration and the ability of retinal ganglion cells, the projection neurons of the retina, to survive after nerve injury. Here we describe research from our lab on the role of inflammation-derived growth factors, suppression of inter-cellular signals among diverse retinal cell types, and combinatorial therapies, along with related studies from other labs, that enable animals with optic nerve injury to regenerate damaged retinal axons back to the brain. These studies raise the possibility that vision might one day be restored to people with optic nerve damage.
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Affiliation(s)
- Yuqin Yin
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA
| | - Silmara De Lima
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA
| | - Hui-Ya Gilbert
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA
| | - Nicholas J Hanovice
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA
| | - Sheri L Peterson
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA
| | - Rheanna M Sand
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Elena G Sergeeva
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Kimberly A Wong
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA
| | - Lili Xie
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA
| | - Larry I Benowitz
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA.,Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
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90
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Hubens WHG, Mohren RJC, Liesenborghs I, Eijssen LMT, Ramdas WD, Webers CAB, Gorgels TGMF. The aqueous humor proteome of primary open angle glaucoma: An extensive review. Exp Eye Res 2020; 197:108077. [PMID: 32470343 DOI: 10.1016/j.exer.2020.108077] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 03/26/2020] [Accepted: 05/18/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND We reviewed the literature on the aqueous humor (AH) proteome of primary open angle glaucoma (POAG) patients in order to obtain deeper insight into the pathophysiology of POAG. METHODS We searched Pubmed and Embase up to May 2019 for studies that compared AH protein composition between POAG (cases) and cataract (controls). Untargeted studies (measuring the whole proteome, by LC-MS/MS) were divided into two subgroups depending on the type of surgery during which POAG AH was collected: glaucoma filtration surgery (subgroup 1) or cataract surgery (subgroup 2). We reanalyzed the raw data (subgroup 1) or combined the reported data (subgroup 2) to perform GO enrichment (GOrilla) and pathway analysis (Pathvisio). RESULTS Out of 93 eligible proteomic studies, seven were untargeted studies that identified 863 AH proteins. We observed 73 differentially expressed proteins in subgroup 1 and 87 differentially expressed proteins in subgroup 2. Both subgroups were characterized by activation of the acute immune response, dysregulation of folate metabolism and dysregulation of the selenium micronutrient network. For subgroup 1 but not for subgroup 2, proteins of the complement system were significantly enriched. CONCLUSION AH proteome of POAG patients shows strong activation of the immune system. In addition, analysis suggests dysregulation of folate metabolism and dysregulation of selenium as underlying contributors. In view of their glaucoma surgery, POAG patients of subgroup 1 most likely are progressive whereas POAG patients in subgroup 2 most likely have stable POAG. The proteome difference between these subgroups suggests that the complement system plays a role in POAG progression.
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Affiliation(s)
- W H G Hubens
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands; Department of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - R J C Mohren
- Maastricht MultiModal Molecular Imaging (M4I) Institute, Division of Imaging Mass Spectrometry, Maastricht University, Maastricht, the Netherlands
| | - I Liesenborghs
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands; Maastricht Centre of Systems Biology (MaCSBio), Maastricht University, Maastricht, the Netherlands
| | - L M T Eijssen
- Department of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands; Department of Bioinformatics - BiGCaT, NUTRIM, Maastricht University, Maastricht, the Netherlands
| | - W D Ramdas
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands
| | - C A B Webers
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands
| | - T G M F Gorgels
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands.
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91
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Tribble JR, Harder JM, Williams PA, John SWM. Ocular hypertension suppresses homeostatic gene expression in optic nerve head microglia of DBA/2 J mice. Mol Brain 2020; 13:81. [PMID: 32450896 PMCID: PMC7249412 DOI: 10.1186/s13041-020-00603-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 04/13/2020] [Indexed: 12/18/2022] Open
Abstract
Glaucoma is the leading cause of irreversible vision loss. Ocular hypertension is a major risk factor for glaucoma and recent work has demonstrated critical early neuroinflammatory insults occur in the optic nerve head following ocular hypertension. Microglia and infiltrating monocytes are likely candidates to drive these neuroinflammatory insults. However, the exact molecular identity / transcriptomic profile of microglia following ocular hypertensive insults is unknown. To elucidate the molecular identity of microglia after long-term exposure to ocular hypertension, we used a mouse model of glaucoma (DBA/2 J). We performed RNA-sequencing of microglia mRNA from the optic nerve head at a time point following ocular hypertensive insults, but preceding detectable neurodegeneration (with microglia identified as being CD45lo/CD11b+/CD11c−). Furthermore, RNA-sequencing was performed on optic nerve head microglia from mice treated with radiation therapy, a potent therapy preventing neuroinflammatory insults. Transcriptomic profiling of optic nerve head microglia mRNA identifies metabolic priming with marked changes in mitochondrial gene expression, and changes to phagocytosis, inflammatory, and sensome pathways. The data predict that many functions of microglia that help maintain tissue homeostasis are affected. Comparative analysis of these data with data from previously published whole optic nerve head tissue or monocyte-only samples from DBA/2 J mice demonstrate that many of the neuroinflammatory signatures in these data sets arise from infiltrating monocytes and not reactive microglia. Finally, our data demonstrate that prophylactic radiation therapy of DBA/2 J mice potently abolishes these microglia metabolic transcriptomic changes at the same time points. Together, our data provide a unique resource for the community to help drive further hypothesis generation and testing in glaucoma.
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Affiliation(s)
- James R Tribble
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Jeffrey M Harder
- The Howard Hughes Medical Institute, The Jackson Laboratory, Bar Harbor, ME, USA
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Simon W M John
- The Howard Hughes Medical Institute, The Jackson Laboratory, Bar Harbor, ME, USA. .,Department of Ophthalmology and Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
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Alawieh AM, Langley EF, Feng W, Spiotta AM, Tomlinson S. Complement-Dependent Synaptic Uptake and Cognitive Decline after Stroke and Reperfusion Therapy. J Neurosci 2020; 40:4042-4058. [PMID: 32291326 PMCID: PMC7219298 DOI: 10.1523/jneurosci.2462-19.2020] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 03/26/2020] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
Despite the success of reperfusion therapy in significantly reducing the extent of infarct expansion after stroke, the effect of revascularization on poststroke neuroinflammation and the role of anti-inflammatory strategies in postreperfusion era are yet to be explored. Here, we investigate whether the neuroinflammatory response may still contribute to neurologic deficits after reperfused stroke by using targeted complement inhibition to suppress poststroke neuroinflammation in mice with or without concurrent reperfusion therapy. Complement inhibition was achieved using B4Crry, an injury site-targeted inhibitor of C3 activation. Following embolic stroke in male C57bl/6 mice, thrombolysis using tissue-plasminogen activator (t-PA) reduced injury and improved motor deficits, but did not improve cognitive outcomes. After both reperfused and non-reperfused stroke, complement activation and opsonization of hippocampal synapses directed ongoing microglia-dependent phagocytosis of synapses for at least 30 d after stroke, leading to a loss of synaptic density that was associated with cognitive decline. B4Crry treatment, alone or in combination with tPA, limited perilesional complement deposition, reduced microgliosis and synaptic uptake, and improved cognitive outcome without affecting regenerative responses. Furthermore, complement inhibition improved the safety, efficacy, and treatment window of reperfusion therapy with t-PA by limiting hemorrhagic transformation. This work thus demonstrates that poststroke neuroinflammation contributes to hemorrhagic transformation and progression of neurodegenerative responses in the brain even following early and successful revascularization.SIGNIFICANCE STATEMENT This study addresses two major challenges facing the treatment of stroke in the era of reperfusion therapy: hemorrhagic transformation and the disconnect between successful revascularization and functional outcomes. We studied how complement-dependent neuroinflammation drives the pathophysiology behind these challenges using a translationally relevant strategy. Complement inhibition was achieved using B4Crry, an injury site-targeted inhibitor of C3 activation. Following embolic stroke, pharmacological thrombolysis limited infarct size, but did not prevent complement activation. In reperfused and non-reperfused stroke, complement activation and opsonization of hippocampal synapses resulted in synaptic phagocytosis and subsequent cognitive decline. B4Crry treatment limited perilesional complement deposition, reduced microgliosis and synaptic uptake, and improved cognitive outcomes. Complement inhibition also improved the safety, efficacy, and treatment window of thrombolytic therapy.
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Affiliation(s)
- Ali M Alawieh
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia 30322
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - E Farris Langley
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Wuwei Feng
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710
| | - Alejandro M Spiotta
- Department of Neurosurgery, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Stephen Tomlinson
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, South Carolina 29425
- Ralph H. Johnson VA Medical Center, Charleston, South Carolina 29401
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93
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Santiago AR, Madeira MH, Boia R, Aires ID, Rodrigues-Neves AC, Santos PF, Ambrósio AF. Keep an eye on adenosine: Its role in retinal inflammation. Pharmacol Ther 2020; 210:107513. [PMID: 32109489 DOI: 10.1016/j.pharmthera.2020.107513] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Adenosine is an endogenous purine nucleoside ubiquitously distributed throughout the body that interacts with G protein-coupled receptors, classified in four subtypes: A1R, A2AR, A2BR and A3R. Among the plethora of functions of adenosine, it has been increasingly recognized as a key mediator of the immune response. Neuroinflammation is a feature of chronic neurodegenerative diseases and contributes to the pathophysiology of several retinal degenerative diseases. Animal models of retinal diseases are helping to elucidate the regulatory roles of adenosine receptors in the development and progression of those diseases. Mounting evidence demonstrates that the adenosinergic system is altered in the retina during pathological conditions, compromising retinal physiology. This review focuses on the roles played by adenosine and the elements of the adenosinergic system (receptors, enzymes, transporters) in the neuroinflammatory processes occurring in the retina. An improved understanding of the molecular and cellular mechanisms of the signalling pathways mediated by adenosine underlying the onset and progression of retinal diseases will pave the way towards the identification of new therapeutic approaches.
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Affiliation(s)
- Ana Raquel Santiago
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal.
| | - Maria H Madeira
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal
| | - Raquel Boia
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Inês Dinis Aires
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Ana Catarina Rodrigues-Neves
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Paulo Fernando Santos
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
| | - António Francisco Ambrósio
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal.
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94
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Tenner AJ. Complement-Mediated Events in Alzheimer's Disease: Mechanisms and Potential Therapeutic Targets. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2020; 204:306-315. [PMID: 31907273 PMCID: PMC6951444 DOI: 10.4049/jimmunol.1901068] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 10/18/2019] [Indexed: 12/11/2022]
Abstract
An estimated 5.7 million Americans suffer from Alzheimer's disease in the United States, with no disease-modifying treatments to prevent or treat cognitive deficits associated with the disease. Genome-wide association studies suggest that an enhancement of clearance mechanisms and/or promotion of an anti-inflammatory response may slow or prevent disease progression. Increasing awareness of distinct roles of complement components in normal brain development and function and in neurodegenerative disorders align with complement-mediated responses, and thus, thorough understanding of these molecular pathways is needed to facilitate successful therapeutic design. Both beneficial and detrimental effects of C1q as well as contributions to local inflammation by C5a-C5aR1 signaling in brain highlight the need for precision of therapeutic design. The potential benefit of β-amyloid clearance from the circulation via CR1-mediated mechanisms is also reviewed. Therapies that suppress inflammation while preserving protective effects of complement could be tested now to slow the progression of this debilitating disease.
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Affiliation(s)
- Andrea J Tenner
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, CA 92697;
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697;
- Department of Pathology and Laboratory Medicine, School of Medicine, University of California Irvine, Irvine, CA 92697; and
- Institute for Memory Impairment and Neurological Disorders, University of California Irvine, Irvine, CA 92697
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95
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Tribble JR, Vasalauskaite A, Redmond T, Young RD, Hassan S, Fautsch MP, Sengpiel F, Williams PA, Morgan JE. Midget retinal ganglion cell dendritic and mitochondrial degeneration is an early feature of human glaucoma. Brain Commun 2019; 1:fcz035. [PMID: 31894207 PMCID: PMC6928391 DOI: 10.1093/braincomms/fcz035] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/29/2019] [Accepted: 11/01/2019] [Indexed: 12/31/2022] Open
Abstract
Glaucoma is characterized by the progressive dysfunction and loss of retinal ganglion cells. However, the earliest degenerative events that occur in human glaucoma are relatively unknown. Work in animal models has demonstrated that retinal ganglion cell dendrites remodel and atrophy prior to the loss of the cell soma. Whether this occurs in human glaucoma has yet to be elucidated. Serial block face scanning electron microscopy is well established as a method to determine neuronal connectivity at high resolution but so far has only been performed in normal retina from animal models. To assess the structure-function relationship of early human glaucomatous neurodegeneration, regions of inner retina assessed to have none-to-moderate loss of retinal ganglion cell number were processed using serial block face scanning electron microscopy (n = 4 normal retinas, n = 4 glaucoma retinas). This allowed detailed 3D reconstruction of retinal ganglion cells and their intracellular components at a nanometre scale. In our datasets, retinal ganglion cell dendrites degenerate early in human glaucoma, with remodelling and redistribution of the mitochondria. We assessed the relationship between visual sensitivity and retinal ganglion cell density and discovered that this only partially conformed to predicted models of structure-function relationships, which may be affected by these early neurodegenerative changes. In this study, human glaucomatous retinal ganglion cells demonstrate compartmentalized degenerative changes as observed in animal models. Importantly, in these models, many of these changes have been demonstrated to be reversible, increasing the likelihood of translation to viable therapies for human glaucoma.
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Affiliation(s)
- James R Tribble
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ Wales, UK
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 112 82 Stockholm, Sweden
| | | | - Tony Redmond
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ Wales, UK
| | - Robert D Young
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ Wales, UK
| | - Shoaib Hassan
- School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XW Wales, UK
| | | | - Frank Sengpiel
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX Wales, UK
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 112 82 Stockholm, Sweden
| | - James E Morgan
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ Wales, UK
- School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XW Wales, UK
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96
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Li S, Li D, Shao M, Cao W, Sun X. Decreased Serum Levels of Complement C3 Reflect Complement System Dysregulation in Patients With Primary Open-angle Glaucoma: Results From a Pilot Study. J Glaucoma 2019; 27:761-768. [PMID: 30036292 DOI: 10.1097/ijg.0000000000001014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
PURPOSE To evaluate the serum complement component (C)3 concentration in patients with primary open-angle glaucoma (POAG) and to investigate the association between C3 levels and POAG severity. MATERIALS AND METHODS This study enrolled 190 consecutive POAG patients and 204 normal control subjects. A detailed eye and systematic examination, including intraocular pressure, gonioscopy, fundus photography, A-scan ultrasound, visual field testing, electrocardiograms, x-rays, liver function, renal function, infectious disease, etc., and measurement of serum C3 concentration by immunoturbidimetry, was performed. The subgroups were classified according to age (17 to 29, 30 to 49, 50 to 69, 70+ y), sex, and visual field: mild (MD≤6 dB), moderate (6 dB<MD≤12 dB), and severe (MD>12 dB) glaucoma. RESULTS The serum C3 level of the POAG (95.63±17.71 mg/dL) was ∼20.93% lower than that of the control group (115.65±22.19 mg/dL) (P<0.001). A similar result was observed when serum levels of C3 were compared between the POAG and control groups with respect to age and sex. The mean serum C3 level was lowest in the severe POAG group (85.18±19.62 mg/dL), followed by the moderate POAG group (96.62±12.63 mg/dL) and the mild POAG group (110.44±14.89 mg/dL) (P<0.001). Multiple logistic regression analyses revealed a significant correlation between the C3 levels and the vertical cup-disc ratio (B=-0.373, P=0.026), C3 levels and MD (B=-0.546, P=0.001). Logistic regression analyses revealed that serum C3 levels were associated (odds ratio=0.939, 95% CI=0.901-0.979, P=0.003) with severity of POAG. CONCLUSIONS The POAG patients had decreased C3 levels, which were further negatively associated with POAG severity, suggesting the involvement of C3 in the pathomechanisms of POAG.
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Affiliation(s)
- Shengjie Li
- Departments of Clinical Laboratory.,Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University
| | - Danhui Li
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Medical School, Xi'an Jiaotong University, Xi'an, Shanxi, China
| | | | - Wenjun Cao
- Departments of Clinical Laboratory.,Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University
| | - Xinghuai Sun
- Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University.,State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University.,Key Laboratory of Myopia, Ministry of Health, Fudan University.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai
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97
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Krishnan A, Kocab AJ, Zacks DN, Marshak-Rothstein A, Gregory-Ksander M. A small peptide antagonist of the Fas receptor inhibits neuroinflammation and prevents axon degeneration and retinal ganglion cell death in an inducible mouse model of glaucoma. J Neuroinflammation 2019; 16:184. [PMID: 31570110 PMCID: PMC6767653 DOI: 10.1186/s12974-019-1576-3] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 08/29/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Glaucoma is a complex, multifactorial disease where apoptosis, microglia activation, and inflammation have been linked to the death of retinal ganglion cells (RGCs) and axon degeneration. We demonstrated previously that FasL-Fas signaling was required for axon degeneration and death of RGCs in chronic and inducible mouse models of glaucoma and that Fas activation triggered RGC apoptosis, glial activation, and inflammation. Here, we investigated whether targeting the Fas receptor with a small peptide antagonist, ONL1204, has anti-inflammatory and neuroprotective effects in a microbead-induced mouse model of glaucoma. METHODS Intracameral injection of microbeads was used to elevate intraocular pressure (IOP) in Fas-deficient (Faslpr) mice and WT C57BL/6J mice that received an intravitreal injection of the Fas inhibitor, ONL1204 (2 μg/1 μl) (or vehicle only), on day 0 or day 7 after microbead injection. The IOP was monitored by rebound tonometry, and at 28 days post-microbead injection, Brn3a-stained RGCs and paraphenylenediamine (PPD)-stained axons were analyzed. The effects of ONL1204 on retinal microglia activation and the expression of inflammatory genes were analyzed by immunostaining of retinal flatmounts and quantitative PCR (qPCR). RESULTS Rebound tonometry showed equivalent elevation of IOP in all groups of microbead-injected mice. At 28 days post-microbead injection, the RGC and axon counts from microbead-injected Faslpr mice were equivalent to saline-injected (no IOP elevation) controls. Treatment with ONL1204 also significantly reduced RGC death and loss of axons in microbead-injected WT mice when compared to vehicle-treated controls, even when administered after IOP elevation. Confocal analysis of Iba1-stained retinal flatmounts and qPCR demonstrated that ONL1204 also abrogated microglia activation and inhibited the induction of multiple genes implicated in glaucoma, including cytokines and chemokines (GFAP, Caspase-8, TNFα, IL-1β, IL-6, IL-18, MIP-1α, MIP-1β, MIP-2, MCPI, and IP10), components of the complement cascade (C3, C1Q), Toll-like receptor pathway (TLR4), and inflammasome pathway (NLRP3). CONCLUSIONS These results serve as proof-of-principal that the small peptide inhibitor of the Fas receptor, ONL1204, can provide robust neuroprotection in an inducible mouse model of glaucoma, even when administered after IOP elevation. Moreover, Fas signaling contributes to the pathogenesis of glaucoma through activation of both apoptotic and inflammatory pathways.
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Affiliation(s)
- Anitha Krishnan
- Department of Ophthalmology, The Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, 20 Staniford Street, Boston, MA, USA
| | | | - David N Zacks
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Ann Marshak-Rothstein
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Meredith Gregory-Ksander
- Department of Ophthalmology, The Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, 20 Staniford Street, Boston, MA, USA.
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98
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Tsai T, Reinehr S, Maliha AM, Joachim SC. Immune Mediated Degeneration and Possible Protection in Glaucoma. Front Neurosci 2019; 13:931. [PMID: 31543759 PMCID: PMC6733056 DOI: 10.3389/fnins.2019.00931] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 08/19/2019] [Indexed: 12/13/2022] Open
Abstract
The underlying pathomechanisms for glaucoma, one of the most common causes of blindness worldwide, are still not identified. In addition to increased intraocular pressure (IOP), oxidative stress, excitotoxicity, and immunological processes seem to play a role. Several pharmacological or molecular/genetic methods are currently investigated as treatment options for this disease. Altered autoantibody levels were detected in serum, aqueous humor, and tissue sections of glaucoma patients. To further analyze the role of the immune system, an IOP-independent, experimental autoimmune glaucoma (EAG) animal model was developed. In this model, immunization with ocular antigens leads to antibody depositions, misdirected T-cells, retinal ganglion cell death and degeneration of the optic nerve, similar to glaucomatous degeneration in patients. Moreover, an activation of the complement system and microglia alterations were identified in the EAG as well as in ocular hypertension models. The inhibition of these factors can alleviate degeneration in glaucoma models with and without high IOP. Currently, several neuroprotective approaches are tested in distinct models. It is necessary to have systems that cover underlying pathomechanisms, but also allow for the screening of new drugs. In vitro models are commonly used, including single cell lines, mixed-cultures, and even organoids. In ex vivo organ cultures, pathomechanisms as well as therapeutics can be investigated in the whole retina. Furthermore, animal models reveal insights in the in vivo situation. With all these models, several possible new drugs and therapy strategies were tested in the last years. For example, hypothermia treatment, neurotrophic factors or the blockage of excitotoxity. However, further studies are required to reveal the pressure independent pathomechanisms behind glaucoma. There is still an open issue whether immune mechanisms directly or indirectly trigger cell death pathways. Hence, it might be an imbalance between protective and destructive immune mechanisms. Moreover, identified therapy options have to be evaluated in more detail, since deeper insights could lead to better treatment options for glaucoma patients.
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Affiliation(s)
| | | | | | - Stephanie C. Joachim
- Experimental Eye Research, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
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99
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Abstract
Maturation of neuronal circuits requires selective elimination of synaptic connections. Although neuron-intrinsic mechanisms are important in this process, it is increasingly recognized that glial cells also play a critical role. Without proper functioning of these cells, the number, morphology, and function of synaptic contacts are profoundly altered, resulting in abnormal connectivity and behavioral abnormalities. In addition to their role in synaptic refinement, glial cells have also been implicated in pathological synapse loss and dysfunction following injury or nervous system degeneration in adults. Although mechanisms regulating glia-mediated synaptic elimination are still being uncovered, it is clear this complex process involves many cues that promote and inhibit the removal of specific synaptic connections. Gaining a greater understanding of these signals and the contribution of different cell types will not only provide insight into this critical biological event but also be instrumental in advancing knowledge of brain development and neural disease.
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Affiliation(s)
- Daniel K. Wilton
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Lasse Dissing-Olesen
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Beth Stevens
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
- Stanley Center, Broad Institute, Cambridge, Massachusetts 02142, USA
- Howard Hughes Medical Institute, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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100
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Todd L, Palazzo I, Suarez L, Liu X, Volkov L, Hoang TV, Campbell WA, Blackshaw S, Quan N, Fischer AJ. Reactive microglia and IL1β/IL-1R1-signaling mediate neuroprotection in excitotoxin-damaged mouse retina. J Neuroinflammation 2019; 16:118. [PMID: 31170999 PMCID: PMC6555727 DOI: 10.1186/s12974-019-1505-5] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/09/2019] [Indexed: 12/12/2022] Open
Abstract
Background Microglia and inflammation have context-specific impacts upon neuronal survival in different models of central nervous system (CNS) disease. Herein, we investigate how inflammatory mediators, including microglia, interleukin 1 beta (IL1β), and signaling through interleukin 1 receptor type 1 (IL-1R1), influence the survival of retinal neurons in response to excitotoxic damage. Methods Excitotoxic retinal damage was induced via intraocular injections of NMDA. Microglial phenotype and neuronal survival were assessed by immunohistochemistry. Single-cell RNA sequencing was performed to obtain transcriptomic profiles. Microglia were ablated by using clodronate liposome or PLX5622. Retinas were treated with IL1β prior to NMDA damage and cell death was assessed in wild type, IL-1R1 null mice, and mice expressing IL-1R1 only in astrocytes. Results NMDA-induced damage included neuronal cell death, microglial reactivity, upregulation of pro-inflammatory cytokines, and genes associated with IL1β-signaling in different types of retinal neurons and glia. Expression of the IL1β receptor, IL-1R1, was evident in astrocytes, endothelial cells, some Müller glia, and OFF bipolar cells. Ablation of microglia with clodronate liposomes or Csf1r antagonist (PLX5622) resulted in elevated cell death and diminished neuronal survival in excitotoxin-damaged retinas. Exogenous IL1β stimulated the proliferation and reactivity of microglia in the absence of damage, reduced numbers of dying cells in damaged retinas, and increased neuronal survival following an insult. IL1β failed to provide neuroprotection in the IL-1R1-null retina, but IL1β-mediated neuroprotection was rescued when expression of IL-1R1 was restored in astrocytes. Conclusions We conclude that reactive microglia provide protection to retinal neurons, since the absence of microglia is detrimental to survival. We propose that, at least in part, the survival-influencing effects of microglia may be mediated by IL1β, IL-1R1, and interactions of microglia and other macroglia. Electronic supplementary material The online version of this article (10.1186/s12974-019-1505-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Levi Todd
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Isabella Palazzo
- Department of Neuroscience, College of Medicine, The Ohio State University, 3020 Graves Hall, 333 W. 10th Ave, Columbus, OH, 43210-1239, USA
| | - Lilianna Suarez
- Department of Neuroscience, College of Medicine, The Ohio State University, 3020 Graves Hall, 333 W. 10th Ave, Columbus, OH, 43210-1239, USA
| | - Xiaoyu Liu
- Institute for Behavioral Medicine Research, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Leo Volkov
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Thanh V Hoang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Warren A Campbell
- Department of Neuroscience, College of Medicine, The Ohio State University, 3020 Graves Hall, 333 W. 10th Ave, Columbus, OH, 43210-1239, USA
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ning Quan
- Institute for Behavioral Medicine Research, College of Medicine, The Ohio State University, Columbus, OH, USA.,Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Andy J Fischer
- Department of Neuroscience, College of Medicine, The Ohio State University, 3020 Graves Hall, 333 W. 10th Ave, Columbus, OH, 43210-1239, USA.
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