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Karperien AL, Jelinek HF. Box-Counting Fractal Analysis: A Primer for the Clinician. ADVANCES IN NEUROBIOLOGY 2024; 36:15-55. [PMID: 38468026 DOI: 10.1007/978-3-031-47606-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
This chapter lays out the elementary principles of fractal geometry underpinning much of the rest of this book. It assumes a minimal mathematical background, defines the key principles and terms in context, and outlines the basics of a fractal analysis method known as box counting and how it is used to perform fractal, lacunarity, and multifractal analyses. As a standalone reference, this chapter grounds the reader to be able to understand, evaluate, and apply essential methods to appreciate and heal the exquisitely detailed fractal geometry of the brain.
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Affiliation(s)
| | - Herbert F Jelinek
- Department of Medical Sciences and Biotechnology Center, Khalifa University, Abu Dhabi, UAE
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Kumar S, Akopian A, Bloomfield SA. Neuroprotection of Retinal Ganglion Cells Suppresses Microglia Activation in a Mouse Model of Glaucoma. Invest Ophthalmol Vis Sci 2023; 64:24. [PMID: 37318444 DOI: 10.1167/iovs.64.7.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023] Open
Abstract
Purpose Microglial activation has been implicated in many neurodegenerative eye diseases, but the interrelationship between cell loss and microglia activation remains unclear. In glaucoma, there is no consensus yet whether microglial activation precedes or is a consequence of retinal ganglion cell (RGC) degeneration. We therefore investigated the temporal and spatial appearance of activated microglia in retina and their correspondence to RGC degeneration in glaucoma. Methods We used an established microbead occlusion model of glaucoma in mouse whereby intraocular pressure (IOP) was elevated. Specific antibodies were used to immunolabel microglia in resting and activated states. To block retinal gap junction (GJ) communication, which has been shown previously to provide significant neuroprotection of RGCs, the GJ blocker meclofenamic acid was administered or connexin36 (Cx36) GJ subunits were ablated genetically. We then studied microglial activation at different time points after microbead injection in control and neuroprotected retinas. Results Histochemical analysis of flatmount retinas revealed major changes in microglia morphology, density, and immunoreactivity in microbead-injected eyes. An early stage of microglial activation followed IOP elevation, as indicated by changes in morphology and cell density, but preceded RGC death. In contrast, the later stage of microglia activation, associated with upregulation of major histocompatibility complex class II expression, corresponded temporally to the initial loss of RGCs. However, we found that protection of RGCs afforded by GJ blockade or genetic ablation largely suppressed microglial changes at all stages of activation in glaucomatous retinas. Conclusions Together, our data strongly suggest that microglia activation in glaucoma is a consequence, rather than a cause, of initial RGC degeneration and death.
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Affiliation(s)
- Sandeep Kumar
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
| | - Abram Akopian
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
| | - Stewart A Bloomfield
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
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3
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Rodrigo MJ, Subías M, Montolío A, Méndez-Martínez S, Martínez-Rincón T, Arias L, García-Herranz D, Bravo-Osuna I, Garcia-Feijoo J, Pablo L, Cegoñino J, Herrero-Vanrell R, Carretero A, Ruberte J, Garcia-Martin E, Pérez del Palomar A. Analysis of Parainflammation in Chronic Glaucoma Using Vitreous-OCT Imaging. Biomedicines 2021; 9:biomedicines9121792. [PMID: 34944608 PMCID: PMC8698891 DOI: 10.3390/biomedicines9121792] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/22/2021] [Accepted: 11/25/2021] [Indexed: 11/25/2022] Open
Abstract
Glaucoma causes blindness due to the progressive death of retinal ganglion cells. The immune response chronically and subclinically mediates a homeostatic role. In current clinical practice, it is impossible to analyse neuroinflammation non-invasively. However, analysis of vitreous images using optical coherence tomography detects the immune response as hyperreflective opacities. This study monitors vitreous parainflammation in two animal models of glaucoma, comparing both healthy controls and sexes over six months. Computational analysis characterizes in vivo the hyperreflective opacities, identified histologically as hyalocyte-like Iba-1+ (microglial marker) cells. Glaucomatous eyes showed greater intensity and number of vitreous opacities as well as dynamic fluctuations in the percentage of activated cells (50–250 microns2) vs. non-activated cells (10–50 microns2), isolated cells (10 microns2) and complexes (>250 microns2). Smaller opacities (isolated cells) showed the highest mean intensity (intracellular machinery), were the most rounded at earlier stages (recruitment) and showed the greatest change in orientation (motility). Study of vitreous parainflammation could be a biomarker of glaucoma onset and progression.
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Affiliation(s)
- María Jesús Rodrigo
- Department of Ophthalmology, Miguel Servet University Hospital, 50009 Zaragoza, Spain; (M.S.); (S.M.-M.); (T.M.-R.); (L.A.); (L.P.); (E.G.-M.)
- Miguel Servet Ophthalmology Research Group (GIMSO), Aragon Health Research Institute (IIS Aragon), 50009 Zaragoza, Spain
- National Ocular Pathology Network (OFTARED), Carlos III Health Institute, 28040 Madrid, Spain;
- Correspondence: ; Tel.: +34-976765558; Fax: +34-976566234
| | - Manuel Subías
- Department of Ophthalmology, Miguel Servet University Hospital, 50009 Zaragoza, Spain; (M.S.); (S.M.-M.); (T.M.-R.); (L.A.); (L.P.); (E.G.-M.)
- Miguel Servet Ophthalmology Research Group (GIMSO), Aragon Health Research Institute (IIS Aragon), 50009 Zaragoza, Spain
| | - Alberto Montolío
- Biomaterials Group, Aragon Engineering Research Institute (I3A), University of Zaragoza, 50018 Zaragoza, Spain; (A.M.); (J.C.); (A.P.d.P.)
- Department of Mechanical Engineering, University of Zaragoza, 50018 Zaragoza, Spain
| | - Silvia Méndez-Martínez
- Department of Ophthalmology, Miguel Servet University Hospital, 50009 Zaragoza, Spain; (M.S.); (S.M.-M.); (T.M.-R.); (L.A.); (L.P.); (E.G.-M.)
- Miguel Servet Ophthalmology Research Group (GIMSO), Aragon Health Research Institute (IIS Aragon), 50009 Zaragoza, Spain
| | - Teresa Martínez-Rincón
- Department of Ophthalmology, Miguel Servet University Hospital, 50009 Zaragoza, Spain; (M.S.); (S.M.-M.); (T.M.-R.); (L.A.); (L.P.); (E.G.-M.)
- Miguel Servet Ophthalmology Research Group (GIMSO), Aragon Health Research Institute (IIS Aragon), 50009 Zaragoza, Spain
| | - Lorena Arias
- Department of Ophthalmology, Miguel Servet University Hospital, 50009 Zaragoza, Spain; (M.S.); (S.M.-M.); (T.M.-R.); (L.A.); (L.P.); (E.G.-M.)
- Miguel Servet Ophthalmology Research Group (GIMSO), Aragon Health Research Institute (IIS Aragon), 50009 Zaragoza, Spain
| | - David García-Herranz
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Department of Pharmaceutics and Food Technology, Faculty of Pharmacy, Complutense University of Madrid (UCM), 28040 Madrid, Spain;
- Health Research Institute of the San Carlos Clinical Hospital (IdISSC), 28040 Madrid, Spain
- University Institute of Industrial Pharmacy (IUFI), School of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain;
| | - Irene Bravo-Osuna
- University Institute of Industrial Pharmacy (IUFI), School of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain;
| | - Julian Garcia-Feijoo
- Department of Ophthalmology, San Carlos Clinical Hospital, UCM, 28040 Madrid, Spain;
| | - Luis Pablo
- Department of Ophthalmology, Miguel Servet University Hospital, 50009 Zaragoza, Spain; (M.S.); (S.M.-M.); (T.M.-R.); (L.A.); (L.P.); (E.G.-M.)
- Miguel Servet Ophthalmology Research Group (GIMSO), Aragon Health Research Institute (IIS Aragon), 50009 Zaragoza, Spain
- National Ocular Pathology Network (OFTARED), Carlos III Health Institute, 28040 Madrid, Spain;
| | - José Cegoñino
- Biomaterials Group, Aragon Engineering Research Institute (I3A), University of Zaragoza, 50018 Zaragoza, Spain; (A.M.); (J.C.); (A.P.d.P.)
- Department of Mechanical Engineering, University of Zaragoza, 50018 Zaragoza, Spain
| | - Rocio Herrero-Vanrell
- National Ocular Pathology Network (OFTARED), Carlos III Health Institute, 28040 Madrid, Spain;
- University Institute of Industrial Pharmacy (IUFI), School of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain;
| | - Ana Carretero
- Centre for Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain; (A.C.); (J.R.)
- CIBER for Diabetes and Associated Metabolic Diseases (CIBERDEM), 28029 Madrid, Spain
- Department of Animal Health and Anatomy, School of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Jesus Ruberte
- Centre for Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain; (A.C.); (J.R.)
- CIBER for Diabetes and Associated Metabolic Diseases (CIBERDEM), 28029 Madrid, Spain
- Department of Animal Health and Anatomy, School of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Elena Garcia-Martin
- Department of Ophthalmology, Miguel Servet University Hospital, 50009 Zaragoza, Spain; (M.S.); (S.M.-M.); (T.M.-R.); (L.A.); (L.P.); (E.G.-M.)
- Miguel Servet Ophthalmology Research Group (GIMSO), Aragon Health Research Institute (IIS Aragon), 50009 Zaragoza, Spain
- National Ocular Pathology Network (OFTARED), Carlos III Health Institute, 28040 Madrid, Spain;
| | - Amaya Pérez del Palomar
- Biomaterials Group, Aragon Engineering Research Institute (I3A), University of Zaragoza, 50018 Zaragoza, Spain; (A.M.); (J.C.); (A.P.d.P.)
- Department of Mechanical Engineering, University of Zaragoza, 50018 Zaragoza, Spain
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4
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Trost A, Motloch K, Koller A, Bruckner D, Runge C, Schroedl F, Bogner B, Kaser-Eichberger A, Strohmaier C, Ladek AM, Preishuber-Pfluegl J, Brunner SM, Aigner L, Reitsamer HA. Inhibition of the cysteinyl leukotriene pathways increases survival of RGCs and reduces microglial activation in ocular hypertension. Exp Eye Res 2021; 213:108806. [PMID: 34715090 DOI: 10.1016/j.exer.2021.108806] [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: 05/26/2021] [Revised: 08/05/2021] [Accepted: 10/21/2021] [Indexed: 10/20/2022]
Abstract
Glaucoma is the second leading cause of blindness worldwide. This multifactorial, neurodegenerative group of diseases is characterized by the progressive loss of retinal ganglion cells (RGCs) and their axons, leading to irreversible visual impairment and blindness. There is a huge unmet and urging need for the development of new and translatable strategies and treatment options to prevent this progressive loss of RGC. Accumulating evidence points towards a critical role of neuroinflammation, in particular microglial cells, in the pathogenesis of glaucoma. Leukotrienes are mediators of neuroinflammation and are involved in many neurodegenerative diseases. Therefore, we tested the leukotriene receptors CysLT1R/GPR17-selective antagonist Montelukast (MTK) for its efficacy to modulate the reactive state of microglia in order to ameliorate RGCs loss in experimental glaucoma. Ocular hypertension (OHT) was induced unilaterally by injection of 8 μm magnetic microbead (MB) into the anterior chamber of female Brown Norway rats. The contralateral, untreated eye served as control. Successful induction of OHT was verified by daily IOP measurement using a TonoLab rebound tonometer. Simultaneously to OHT induction, one group received daily MTK treatment and the control group vehicle solution by oral gavage. Animals were sacrificed 13-15 days after MB injection. Retina and optic nerves (ON) of OHT and contralateral eyes were analyzed by immunofluorescence with specific markers for RGCs (Brn3a), microglial cells/macrophages (Iba1 and CD68), and cysteinyl leukotriene pathway receptors (CysLT1R and GPR17). Protein labeling was documented by confocal microscopy and analyzed with ImageJ plugins. Further, mRNA expression of genes of the inflammatory and leukotriene pathway was analyzed in retinal tissue. MTK treatment resulted in a short-term IOP reduction at day 2, which dissipated by day 5 of OHT induction in MTK treated animals. Furthermore, MTK treatment resulted in a decreased activation of Iba1+ microglial cells in the retina and ON, and in a significantly increased RGC survival in OHT eyes. Within the retina, GPR17 and CysLT1R expression was demonstrated in single RCGs and in microglial cells respectively. Further, increased mRNA expression of pro-inflammatory genes was detected in OHT induced retinas. In the ON, OHT induction increased the number of GPR17+ cells, showing a trend of reduction following MTK treatment. This study shows for the first time a significantly increased RGC survival in an acute OHT model following treatment with the leukotriene receptor antagonist MTK. These results strongly suggest a neuroprotective effect of MTK and a potential new therapeutic strategy for glaucoma treatment.
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Affiliation(s)
- Andrea Trost
- University Clinic of Ophthalmology and Optometry, Research Program for Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020, Salzburg, Austria.
| | - Karolina Motloch
- University Clinic of Ophthalmology and Optometry, Research Program for Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020, Salzburg, Austria
| | - Andreas Koller
- University Clinic of Ophthalmology and Optometry, Research Program for Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020, Salzburg, Austria
| | - Daniela Bruckner
- University Clinic of Ophthalmology and Optometry, Research Program for Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020, Salzburg, Austria
| | - Christian Runge
- University Clinic of Ophthalmology and Optometry, Research Program for Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020, Salzburg, Austria
| | - Falk Schroedl
- University Clinic of Ophthalmology and Optometry, Research Program for Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020, Salzburg, Austria; Center for Anatomy and Cell Biology, Institute of Anatomy and Cell Biology - Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Barbara Bogner
- University Clinic of Ophthalmology and Optometry, Research Program for Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020, Salzburg, Austria
| | - Alexandra Kaser-Eichberger
- University Clinic of Ophthalmology and Optometry, Research Program for Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020, Salzburg, Austria; Center for Anatomy and Cell Biology, Institute of Anatomy and Cell Biology - Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Clemens Strohmaier
- University Clinic of Ophthalmology and Optometry, Research Program for Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020, Salzburg, Austria; Department of Ophthalmology and Optometry, Johannes Kepler University, Linz, Austria
| | - Anja-Maria Ladek
- University Clinic of Ophthalmology and Optometry, Research Program for Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020, Salzburg, Austria
| | - Julia Preishuber-Pfluegl
- University Clinic of Ophthalmology and Optometry, Research Program for Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020, Salzburg, Austria
| | - Susanne Maria Brunner
- University Clinic of Ophthalmology and Optometry, Research Program for Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020, Salzburg, Austria
| | - Ludwig Aigner
- Institute of Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University Salzburg, Austria
| | - Herbert Anton Reitsamer
- University Clinic of Ophthalmology and Optometry, Research Program for Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University Salzburg, Austria
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5
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Frenger MJ, Hecker C, Sindi M, Issberner A, Hartung HP, Meuth SG, Dietrich M, Albrecht P. Semi-Automated Live Tracking of Microglial Activation in CX3CR1 GFP Mice During Experimental Autoimmune Encephalomyelitis by Confocal Scanning Laser Ophthalmoscopy. Front Immunol 2021; 12:761776. [PMID: 34745138 PMCID: PMC8567040 DOI: 10.3389/fimmu.2021.761776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 10/07/2021] [Indexed: 11/13/2022] Open
Abstract
Confocal scanning laser ophthalmoscopy (cSLO) is a non-invasive technique for real-time imaging of the retina. We developed a step-by-step protocol for the semi-automatic evaluation of myeloid cells in cSLO images from CX3CR1GFP mice, expressing green fluorescent protein (GFP) under control of the endogenous CX3C chemokine receptor 1 locus. We identified cSLO parameters allowing us to distinguish animals with experimental autoimmune encephalomyelitis (EAE) from sham-treated/naïve animals. Especially cell count (CC) and the total microglial area (SuA) turned out to be reliable parameters. Comparing the cSLO results with clinical parameters, we found significant correlations between the clinical EAE score and the SuA and of the inner retinal layer thickness, measured by optical coherence tomography, with the CC as well as the SuA. As a final step, we performed immunohistochemistry to confirm that the GFP-expressing cells visualized by the cSLO are Iba1 positive and validated the step-by-step protocol against manual counting. We present a semi-automatic step-by-step protocol with a balance between fast data evaluation and adequate accuracy, which is optimized by the option to manually adapt the contrast threshold. This protocol may be useful for numerous research questions on the role of microglial polarization in models of inflammatory and degenerating CNS diseases involving the retina.
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Affiliation(s)
- Moritz J. Frenger
- Department of Neurology, Heinrich-Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Christina Hecker
- Department of Neurology, Heinrich-Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Mustafa Sindi
- Department of Neurology, Heinrich-Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Andrea Issberner
- Department of Neurology, Heinrich-Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Hans-Peter Hartung
- Department of Neurology, Heinrich-Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
- Brain and Mind Center, University of Sydney, Sydney, NSW, Australia
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Sven G. Meuth
- Department of Neurology, Heinrich-Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Michael Dietrich
- Department of Neurology, Heinrich-Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Philipp Albrecht
- Department of Neurology, Heinrich-Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
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6
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Ruxolitinib Alleviates Uveitis Caused by Salmonella typhimurium Endotoxin. Microorganisms 2021; 9:microorganisms9071481. [PMID: 34361917 PMCID: PMC8307045 DOI: 10.3390/microorganisms9071481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 11/21/2022] Open
Abstract
Uveitis is characterized by inflammatory lesions of intraocular structures. It is one of the important manifestations in patients with Reiter’s syndrome, an inflammatory arthritis, which is caused by enteric infection with bacteria, including Salmonella typhimurium. Corticosteroids remain the most frequently used therapies against uveitis associating with inflammatory arthritis. However, the long-term administration of steroids results in many side effects, and some uveitis patients do not respond to steroid treatment. Non-steroidal treatments are needed for uveitis patients. Our previous study found that Janus kinase (JAK) 1/2 inhibitor, ruxolitinib could suppress the expression of proinflammatory mediators in the ciliary body and iris. However, the impacts of ruxolitinib on ophthalmic features in uveitic eyes are still unknown. In this study, Salmonella typhimurium endotoxin-induced uveitis (EIU) was induced in Sprague Dawley rats by the injection of lipopolysaccharide (LPS). Compared with LPS-induced rats treated with water, ruxolitinib significantly attenuated the clinical manifestations, infiltrating cells and protein exudation in the aqueous humor, and retina–choroid thickening. Amplitudes of b-wave in both scotopic and photopic electroretinogram (ERG), and the amplitude of a-wave in scotopic ERG in EIU animals were alleviated by ruxolitinib. Collectively, we propose ruxolitinib could attenuate endotoxin-induced uveitis and rescue visual functions in rats by inhibiting the JAK2-STAT3 pathway.
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Label-free adaptive optics imaging of human retinal macrophage distribution and dynamics. Proc Natl Acad Sci U S A 2020; 117:30661-30669. [PMID: 33168747 PMCID: PMC7720180 DOI: 10.1073/pnas.2010943117] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Microglia, a type of macrophage, were discovered a little more than a century ago by Pío del Río-Hortega. Since that time, we have gained an immense amount of knowledge on their origin and multifaceted function with the aid of labeling techniques and animal models, among other tools. Only recently have macrophage cells been imaged in living humans. Here we characterize macrophage spatial distribution and temporal dynamics in live human eyes using a label-free adaptive optics imaging approach. This investigation lays a foundation to better understand the body’s immune response not only to ocular diseases like glaucoma, but also to a vast array of neurological diseases with ocular manifestations, including Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis. Microglia are resident central nervous system macrophages and the first responders to neural injury. Until recently, microglia have been studied only in animal models with exogenous or transgenic labeling. While these studies provided a wealth of information on the delicate balance between neuroprotection and neurotoxicity within which these cells operate, extrapolation to human immune function has remained an open question. Here we examine key characteristics of retinal macrophage cells in live human eyes, both healthy and diseased, with the unique capabilities of our adaptive optics–optical coherence tomography approach and owing to their propitious location above the inner limiting membrane (ILM), allowing direct visualization of cells. Our findings indicate that human ILM macrophage cells may be distributed distinctly, age differently, and have different dynamic characteristics than microglia in other animals. For example, we observed a macular pattern that was sparse centrally and peaked peripherally in healthy human eyes. Moreover, human ILM macrophage density decreased with age (∼2% of cells per year). Our results in glaucomatous eyes also indicate that ILM macrophage cells appear to play an early and regionally specific role of nerve fiber layer phagocytosis in areas of active disease. While we investigate ILM macrophage cells distinct from the larger sample of overall retinal microglia, the ability to visualize macrophage cells without fluorescent labeling in the live human eye represents an important advance for both ophthalmology and neuroscience, which may lead to novel disease biomarkers and new avenues of exploration in disease progression.
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8
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Ferreira-Silva J, Aires ID, Boia R, Ambrósio AF, Santiago AR. Activation of Adenosine A 3 Receptor Inhibits Microglia Reactivity Elicited by Elevated Pressure. Int J Mol Sci 2020; 21:ijms21197218. [PMID: 33007835 PMCID: PMC7582754 DOI: 10.3390/ijms21197218] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 09/25/2020] [Accepted: 09/29/2020] [Indexed: 01/22/2023] Open
Abstract
Glaucoma is a progressive chronic retinal degenerative disease and a leading cause of global irreversible blindness, characterized by optic nerve damage and retinal ganglion cell (RGC) death. Elevated intraocular pressure (IOP) is a main risk factor of glaucoma. Neuroinflammation plays an important role in glaucoma. We have been demonstrating that elevated pressure triggers microglia reactivity that contribute to the loss of RGCs. Adenosine, acting on adenosine receptors, is a crucial modulator of microglia phenotype. Microglia express all adenosine receptors. Previously, we demonstrated that the activation of adenosine A3 receptor (A3R) affords protection to the retina, including RGCs, unveiling the possibility for a new strategy for glaucoma treatment. Since microglial cells express A3R, we now studied the ability of a selective A3R agonist (2-Cl-IB-MECA) in controlling microglia reactivity induced by elevated hydrostatic pressure (EHP), used to mimic elevated IOP. The activation of A3R reduced EHP-induced inducible nitric oxide synthase (iNOS) expression, microglia migration and phagocytosis in BV-2 cells. In retinal microglia, proliferation and phagocytosis elicited by EHP were also decreased by A3R activation. This work demonstrates that 2-Cl-IB-MECA, the selective agonist of A3R, is able to hinder microglia reactivity, suggesting that A3R agonists could afford protection against glaucomatous degeneration through the control of neuroinflammation.
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Affiliation(s)
- Joana Ferreira-Silva
- Coimbra Institute for Clinical and Biomedical Research (ICBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.F.-S.); (I.D.A.); (R.B.); (A.F.A.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-548 Coimbra, Portugal
| | - Inês D. Aires
- Coimbra Institute for Clinical and Biomedical Research (ICBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.F.-S.); (I.D.A.); (R.B.); (A.F.A.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-548 Coimbra, Portugal
| | - Raquel Boia
- Coimbra Institute for Clinical and Biomedical Research (ICBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.F.-S.); (I.D.A.); (R.B.); (A.F.A.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-548 Coimbra, Portugal
| | - António Francisco Ambrósio
- Coimbra Institute for Clinical and Biomedical Research (ICBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.F.-S.); (I.D.A.); (R.B.); (A.F.A.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-548 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image, 3000-548 Coimbra, Portugal
| | - Ana Raquel Santiago
- Coimbra Institute for Clinical and Biomedical Research (ICBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.F.-S.); (I.D.A.); (R.B.); (A.F.A.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-548 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image, 3000-548 Coimbra, Portugal
- Correspondence: ; Tel.: +351-239480226
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9
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Guo R. Minocycline Protects Against the Degeneration of Retinal Neurons in Mice. JOURNAL OF EXPLORATORY RESEARCH IN PHARMACOLOGY 2020; 000:1-12. [DOI: 10.14218/jerp.2020.00015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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10
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In vivo imaging reveals transient microglia recruitment and functional recovery of photoreceptor signaling after injury. Proc Natl Acad Sci U S A 2019; 116:16603-16612. [PMID: 31350349 PMCID: PMC6697899 DOI: 10.1073/pnas.1903336116] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Microglia, the resident macrophages of the central nervous system, are critical for synaptic pruning and maintenance and for mitigating injury and neurodegeneration. Determining whether microglia–neuron interactions are beneficial in specific instances has been difficult, largely because of the local and transient nature of the interactions. Using simultaneous optical coherence tomography/scanning laser ophthalmoscopy (SLO) and adaptive optics SLO retinal imaging in mice, we show interactions of microglia and photoreceptors over time scales from seconds to months during injury, degeneration, and repair. In vivo optical assessment of photoreceptor signaling in a large neuronal field encompassing the injured area allows us to relate the time course of these microglia movements to that of the tissue remodeling and functional recovery. Microglia respond to damage and microenvironmental changes within the central nervous system by morphologically transforming and migrating to the lesion, but the real-time behavior of populations of these resident immune cells and the neurons they support have seldom been observed simultaneously. Here, we have used in vivo high-resolution optical coherence tomography (OCT) and scanning laser ophthalmoscopy with and without adaptive optics to quantify the 3D distribution and dynamics of microglia in the living retina before and after local damage to photoreceptors. Following photoreceptor injury, microglia migrated both laterally and vertically through the retina over many hours, forming a tight cluster within the area of visible damage that resolved over 2 wk. In vivo OCT optophysiological assessment revealed that the photoreceptors occupying the damaged region lost all light-driven signaling during the period of microglia recruitment. Remarkably, photoreceptors recovered function to near-baseline levels after the microglia had departed the injury locus. These results demonstrate the spatiotemporal dynamics of microglia engagement and restoration of neuronal function during tissue remodeling and highlight the need for mechanistic studies that consider the temporal and structural dynamics of neuron–microglia interactions in vivo.
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11
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Genetic Rescue Reverses Microglial Activation in Preclinical Models of Retinitis Pigmentosa. Mol Ther 2018; 26:1953-1964. [PMID: 30001913 DOI: 10.1016/j.ymthe.2018.06.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 06/06/2018] [Accepted: 06/15/2018] [Indexed: 12/31/2022] Open
Abstract
Microglia cells (MGCs) play a key role in scavenging pathogens and phagocytosing cellular debris in the central nervous system and retina. Their activation, however, contributes to the progression of multiple degenerative diseases. Given the potential damage created by MGCs, it is important to better understand their mechanism of activation. Here, we explored the role of MGCs in the context of retinitis pigmentosa (RP) by using four independent preclinical mouse models. For therapeutic modeling, tamoxifen-inducible CreER was introduced to explore changes in MGCs when RP progression halted. The phenotypes of the MGCs were observed using live optical coherence tomography, live autofluorescence, and immunohistochemistry. We found that, regardless of genetic background, MGCs were activated in neurodegenerative conditions and migrated beyond the layers where they are typically found to the inner and outer segments, where degeneration was ongoing. Genetic rescue not only halted degeneration but also deactivated MGCs, regardless of whether the intervention occurred at the early, middle, or late stage of the disease. These findings suggest that halting long-term disease progression may be more successful by downregulating MGC activity while co-administering the therapeutic intervention.
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12
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Rathnasamy G, Foulds WS, Ling EA, Kaur C. Retinal microglia - A key player in healthy and diseased retina. Prog Neurobiol 2018; 173:18-40. [PMID: 29864456 DOI: 10.1016/j.pneurobio.2018.05.006] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 03/09/2018] [Accepted: 05/29/2018] [Indexed: 01/04/2023]
Abstract
Microglia, the resident immune cells of the brain and retina, are constantly engaged in the surveillance of their surrounding neural tissue. During embryonic development they infiltrate the retinal tissues and participate in the phagocytosis of redundant neurons. The contribution of microglia in maintaining the purposeful and functional histo-architecture of the adult retina is indispensable. Within the retinal microenvironment, robust microglial activation is elicited by subtle changes caused by extrinsic and intrinsic factors. When there is a disturbance in the cell-cell communication between microglia and other retinal cells, for example in retinal injury, the activated microglia can manifest actions that can be detrimental. This is evidenced by activated microglia secreting inflammatory mediators that can further aggravate the retinal injury. Microglial activation as a harbinger of a variety of retinal diseases is well documented by many studies. In addition, a change in the microglial phenotype which may be associated with aging, may predispose the retina to age-related diseases. In light of the above, the focus of this review is to highlight the role played by microglia in the healthy and diseased retina, based on findings of our own work and from that of others.
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Affiliation(s)
- Gurugirijha Rathnasamy
- Department of Anatomy, Yong Loo Lin School of Medicine, Blk MD10, 4 Medical Drive, National University of Singapore, 117594, Singapore; Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53706, United States
| | - Wallace S Foulds
- Singapore Eye Research Institute Level 6, The Academia, Discovery Tower, 20 College Road, 169856, Singapore; University of Glasgow, Glasgow, Scotland, G12 8QQ, United Kingdom
| | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, Blk MD10, 4 Medical Drive, National University of Singapore, 117594, Singapore
| | - Charanjit Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, Blk MD10, 4 Medical Drive, National University of Singapore, 117594, Singapore.
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13
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Schultz R, Krug M, Precht M, Wohl SG, Witte OW, Schmeer C. Frataxin overexpression in Müller cells protects retinal ganglion cells in a mouse model of ischemia/reperfusion injury in vivo. Sci Rep 2018; 8:4846. [PMID: 29555919 PMCID: PMC5859167 DOI: 10.1038/s41598-018-22887-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 03/02/2018] [Indexed: 01/28/2023] Open
Abstract
Müller cells are critical for retinal function and neuronal survival but can become detrimental in response to retinal ischemia and increased oxidative stress. Elevated oxidative stress increases expression of the mitochondrial enzyme frataxin in the retina, and its overexpression is neuroprotective after ischemia. Whether frataxin expression in Müller cells might improve their function and protect neurons after ischemia is unknown. The aim of this study was to evaluate the effect of frataxin overexpression in Müller cells on neuronal survival after retinal ischemia/reperfusion in the mouse in vivo. Retinal ischemia/reperfusion was induced in mice overexpressing frataxin in Müller cells by transient elevation of intraocular pressure. Retinal ganglion cells survival was determined 14 days after lesion. Expression of frataxin, antioxidant enzymes, growth factors and inflammation markers was determined with qRT-PCR, Western blotting and immunohistochemistry 24 hours after lesion. Following lesion, there was a 65% increase in the number of surviving RGCs in frataxin overexpressing mice. Improved survival was associated with increased expression of the antioxidant enzymes Gpx1 and Sod1 as well as the growth factors Cntf and Lif. Additionally, microglial activation was decreased in these mice. Therefore, support of Müller cell function constitutes a feasible approach to reduce neuronal degeneration after ischemia.
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Affiliation(s)
- Rowena Schultz
- Department of Ophthalmology, Jena University Hospital, Jena, Germany
| | - Melanie Krug
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - Michel Precht
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - Stefanie G Wohl
- Department of Biological Structure, University of Washington Seattle, Seattle, United States
| | - Otto W Witte
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - Christian Schmeer
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany.
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14
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Bilateral early activation of retinal microglial cells in a mouse model of unilateral laser-induced experimental ocular hypertension. Exp Eye Res 2018. [PMID: 29526796 DOI: 10.1016/j.exer.2018.03.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The immune system plays an important role in glaucomatous neurodegeneration. Retinal microglial reactivation associated with ganglion cell loss could reportedly contribute to the glaucoma progression. Recently we have described signs of microglia activation both in contralateral and ocular hypertension (OHT) eyes involving all retinal layers 15 days after OHT laser induction in mice. However, no works available have analyzed the microglial activation at earliest time points after OHT induction (24 h) in this experimental model. Thus, we seek to describe and quantify signs of microglia activation and differences depending on the retinal layer, 24 h after unilateral laser-induced OHT. Two groups of adult Swiss mice were used: age-matched control (naïve) and lasered. In the lasered animals, OHT eyes as well as contralateral eyes were analyzed. Retinal whole-mounts were immunostained with antibodies against Iba-1 and MHC-II. We quantified the number of microglial cells in the photoreceptor layer (OS), outer plexiform layer (OPL), and inner plexiform layer (IPL); the number of microglial vertical processes connecting the OPL and OS; the area of the retina occupied by Iba-1+ cells (Iba1-RA) in the nerve fiber layer-ganglion cell layer (NFL-GCL), the total arbor area of microglial cells in the OPL and IPL and; Iba-1+ cell body area in the OPL, IPL and NFL-GCL. In contralateral and OHT eyes the morphological features of Iba-1+ cell activation were: migration, enlargement of the cell body, higher degree of branching and reorientation of the processes, radial disposition of the soma and processes toward adjacent microglial plexuses, and presence of amoeboid cells acting as macrophages. These signs were more pronounced in OHT eyes. Most of Iba-1+ cells did not express MHC-II; rather, only dendritic and rounded cells expressed it. In comparison with naïve eyes, in OHT eyes and contralateral eyes no significant differences were found in the microglial cell number; but there was a significant increase in Iba1-RA. The total arbor area of microglial cells was significantly decreased in: i) OHT eyes with respect contralateral eyes and naïve-eyes in IPL; ii) OHT eyes with respect to naïve eyes in OPL. The number of microglial vertical processes connecting the OPL and OS were significantly increased in contralateral eyes compared with naïve-eyes and OHT eyes. In OPL, IPL and NFL-GCL, the cell body area of Iba-1+ cells was significantly greater in OHT eyes than in naïve and contralateral eyes, and greater in contralateral eyes than in naïve eyes. A non-proliferative microglial reactivation was detected both in contralateral eyes and in OHT eyes in an early time after unilateral laser-induced OHT (24 h). This fast microglial activation, which involves the contralateral eye, could be mediated by the immune system.
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15
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Nadal-Nicolás FM, Jiménez-López M, Salinas-Navarro M, Sobrado-Calvo P, Vidal-Sanz M, Agudo-Barriuso M. Microglial dynamics after axotomy-induced retinal ganglion cell death. J Neuroinflammation 2017; 14:218. [PMID: 29121969 PMCID: PMC5679427 DOI: 10.1186/s12974-017-0982-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/16/2017] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Microglial cells (MCs) are the sentries of the central nervous system. In health, they are known as surveying MCs because they examine the tissue to maintain the homeostasis. In disease, they activate and, among other functions, become phagocytic to clean the cellular debris. In this work, we have studied the behavior of rat retinal MCs in two models of unilateral complete intraorbital optic nerve axotomy which elicit a different time course of retinal ganglion cell (RGC) loss. METHODS Albino Sprague-Dawley rats were divided into these groups: (a) intact (no surgery), (b) fluorogold (FG) tracing from the superior colliculi, and (c) FG tracing + crush or transection of the left optic nerve. The retinas were dissected from 2 days to 2 months after the lesions (n = 4-12 group/lesion and time point) and then were subjected to Brn3a and Iba1 double immunodetection. In each intact retina, the total number of Brn3a+RGCs and Iba+MCs was quantified. In each traced retina (b and c groups), FG-traced RGCs and phagocytic microglial cells (PMCs, FG+Iba+) were also quantified. Topographical distribution was assessed by neighbor maps. RESULTS In intact retinas, surveying MCs are homogenously distributed in the ganglion cell layer and the inner plexiform layer. Independently of the axotomy model, RGC death occurs in two phases, one quick and one protracted, and there is a lineal and topographical correlation between the appearance of PMCs and the loss of traced RGCs. Furthermore, the clearance of FG+RGCs by PMCs occurs 3 days after the actual loss of Brn3a expression that marks RGC death. In addition, almost 50% of MCs from the inner plexiform layer migrate to the ganglion cell layer during the quick phase of RGC loss, returning to the inner plexiform layer during the slow degeneration phase. Finally, in contrast to what happens in mice, in rats, there is no microglial phagocytosis in the contralateral uninjured retina. CONCLUSIONS Axotomy-induced RGC death occurs earlier than RGC clearance and there is an inverse correlation between RGC loss and PMC appearance, both numerically and topographically, suggesting that phagocytosis occurs as a direct response to RGC death rather than to axonal damage.
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Affiliation(s)
- Francisco M Nadal-Nicolás
- Grupo de Oftalmología Experimental, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, Edificio LAIB Planta 5ª, Carretera Buenavista s/n, 30120, El Palmar, Murcia, Spain.
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Murcia, Spain.
- Present address: Retinal Neurophysiology Section, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Manuel Jiménez-López
- Grupo de Oftalmología Experimental, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, Edificio LAIB Planta 5ª, Carretera Buenavista s/n, 30120, El Palmar, Murcia, Spain
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Murcia, Spain
| | - Manuel Salinas-Navarro
- Grupo de Oftalmología Experimental, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, Edificio LAIB Planta 5ª, Carretera Buenavista s/n, 30120, El Palmar, Murcia, Spain
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Murcia, Spain
| | - Paloma Sobrado-Calvo
- Grupo de Oftalmología Experimental, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, Edificio LAIB Planta 5ª, Carretera Buenavista s/n, 30120, El Palmar, Murcia, Spain
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Murcia, Spain
| | - Manuel Vidal-Sanz
- Grupo de Oftalmología Experimental, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, Edificio LAIB Planta 5ª, Carretera Buenavista s/n, 30120, El Palmar, Murcia, Spain
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Murcia, Spain
| | - Marta Agudo-Barriuso
- Grupo de Oftalmología Experimental, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, Edificio LAIB Planta 5ª, Carretera Buenavista s/n, 30120, El Palmar, Murcia, Spain.
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Murcia, Spain.
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16
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Wang J, Valiente-Soriano FJ, Nadal-Nicolás FM, Rovere G, Chen S, Huang W, Agudo-Barriuso M, Jonas JB, Vidal-Sanz M, Zhang X. MicroRNA regulation in an animal model of acute ocular hypertension. Acta Ophthalmol 2017; 95:e10-e21. [PMID: 27535721 PMCID: PMC6213559 DOI: 10.1111/aos.13227] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 07/10/2016] [Indexed: 12/12/2022]
Abstract
Purpose To analyse miRNA regulation in a rat model of acute ocular hypertension (AOH). Methods Acute ocular hypertension (AOH) was induced in the left eye of adult albino rats by inserting a cannula connected with a saline container into the anterior chamber. The contralateral eye served as a control. Seven days later, animals were killed. Retinas were used either for quantitative analysis of retinal ganglion cells (RGCs) and microglial cells or for miRNA array hybridization, qRT‐PCR and Western blotting. Results Anatomically, AOH caused axonal degeneration, a significant loss of RGCs and a significant increase in microglial cells in the ganglion cell layer. The miRNAs microarray analysis revealed 31 differentially expressed miRNAs in the AOH versus control group, and the regulation of 12 selected microRNAs was further confirmed by qRT‐PCR. Bioinformatic analysis indicates that several signalling pathways are putatively regulated by the validated miRNAs. Of particular interest was the inflammatory pathway signalled by mitogen‐activated protein kinases (MAPKs). In agreement with the in silico analysis, p38 MAP kinase, tumour necrosis factor‐alpha (TNF‐α) and iNOS proteins were significantly upregulated in the AOH retinas. Conclusions Acute IOP elevation led to changes in the expression of miRNAs, whose target genes were associated with the regulation of microglia‐mediated neuroinflammation or neural apoptosis. Addressing miRNAs in the process of retinal ischaemia and optic nerve damage in association with high IOP elevation may open new avenues in preventing retinal ganglion cell apoptosis and may serve as target for future therapeutic regimen in acute ocular hypertension and retinal ischaemic conditions.
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Affiliation(s)
- Jiawei Wang
- Zhongshan Ophthalmic Center; State Key Laboratory of Ophthalmology; Sun Yat-Sen University; Guangzhou China
- Eye Center of Shandong University; The Second Hospital of Shandong University; Jinan China
| | - Francisco J. Valiente-Soriano
- Department of Ophthalmology; University of Murcia and Murcian Institute of Biosanitary Research-Hospital Arrixaca (IMIB-Arrixaca); Murcia Spain
| | - Francisco M. Nadal-Nicolás
- Department of Ophthalmology; University of Murcia and Murcian Institute of Biosanitary Research-Hospital Arrixaca (IMIB-Arrixaca); Murcia Spain
| | - Giuseppe Rovere
- Department of Ophthalmology; University of Murcia and Murcian Institute of Biosanitary Research-Hospital Arrixaca (IMIB-Arrixaca); Murcia Spain
| | - Shida Chen
- Zhongshan Ophthalmic Center; State Key Laboratory of Ophthalmology; Sun Yat-Sen University; Guangzhou China
| | - Wenbin Huang
- Zhongshan Ophthalmic Center; State Key Laboratory of Ophthalmology; Sun Yat-Sen University; Guangzhou China
| | - Marta Agudo-Barriuso
- Department of Ophthalmology; University of Murcia and Murcian Institute of Biosanitary Research-Hospital Arrixaca (IMIB-Arrixaca); Murcia Spain
| | - Jost B. Jonas
- Department of Ophthalmology; Medical Faculty Mannheim; Heidelberg University; Heidelberg Germany
| | - Manuel Vidal-Sanz
- Department of Ophthalmology; University of Murcia and Murcian Institute of Biosanitary Research-Hospital Arrixaca (IMIB-Arrixaca); Murcia Spain
| | - Xiulan Zhang
- Zhongshan Ophthalmic Center; State Key Laboratory of Ophthalmology; Sun Yat-Sen University; Guangzhou China
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17
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Feng L, Liu X. NLRP3 inflammasome in retinal ganglion cell loss in optic neuropathy. Neural Regen Res 2016; 11:1077-8. [PMID: 27630687 PMCID: PMC4994446 DOI: 10.4103/1673-5374.187036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Liang Feng
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL, USA
| | - Xiaorong Liu
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL, USA
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18
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Yin H, Yin H, Zhang W, Miao Q, Qin Z, Guo S, Fu Q, Ma J, Wu F, Yin J, Yang Y, Fang X. Transcorneal electrical stimulation promotes survival of retinal ganglion cells after optic nerve transection in rats accompanied by reduced microglial activation and TNF-α expression. Brain Res 2016; 1650:10-20. [PMID: 27569587 DOI: 10.1016/j.brainres.2016.08.034] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 08/20/2016] [Accepted: 08/24/2016] [Indexed: 11/26/2022]
Abstract
Microglial activation plays a crucial role in the pathological processes of various retinal and optic nerve diseases. TNF-α is a pro-inflammatory cytokine that is rapidly upregulated and promotes retinal ganglion cells (RGCs) death after optic nerve injury. However, the cellular source of TNF-α after optic nerve injury remains unclear. Thus, we aimed to determine the changes of retinal microglial activation in a rat model of optic nerve transection (ONT) after transcorneal electrical stimulation (TES). Furthermore, we assessed TNF-α expression after ONT and evaluated the effects of TES on TNF-α production. Rats were divided into 2 control groups receiving a sham surgery procedure, 2 ONT+Sham TES groups, and 2 ONT+TES groups. The rats were sacrificed on day 7 or 14 after ONT. RGCs were retrogradely labelled by Fluorogold (FG) 7 days before ONT, one TES group and corresponding controls were stimulated on day 0, 4, and the second were stimulated on day 0, 4, 7, 10. Whole-mount immunohistofluorescence, quantification of RGCs and microglia, and western blot analysis were performed on day 7 and 14 after ONT. TES significantly increased RGCs survival on day 7 and 14 after ONT, which was accompanied by reduced microglia on day 7, but not 14. TNF-α was co-localized with ameboid microglia and significantly increased on day 7 and 14 after ONT. TES significantly reduced TNF-α production on day 7 and 14 after ONT. Our study demonstrated that TES promotes RGCs survival after ONT accompanied by reduced microglial activation and microglia-derived TNF-α production.
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Affiliation(s)
- Houmin Yin
- Department of Neurology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China
| | - Houfa Yin
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Wei Zhang
- Department of Orthopedics, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China
| | - Qi Miao
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Zhenwei Qin
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Shenchao Guo
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Qiuli Fu
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Jian Ma
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Fang Wu
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Jinfu Yin
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Yabo Yang
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Xiaoyun Fang
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China; Zhejiang Provincial Key Laboratory of Ophthalmology, Hangzhou, Zhejiang Province, China.
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19
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Wang J, Chen S, Zhang X, Huang W, Jonas JB. Intravitreal triamcinolone acetonide, retinal microglia and retinal ganglion cell apoptosis in the optic nerve crush model. Acta Ophthalmol 2016; 94:e305-11. [PMID: 25708663 DOI: 10.1111/aos.12698] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Accepted: 01/12/2015] [Indexed: 01/20/2023]
Abstract
PURPOSE To evaluate the effect of intravitreal triamcinolone acetonide (TA) on the activation of retinal microglia cells (RMGCs) and survival of retinal ganglion cells (RGCs) in an optic nerve crush (ONC) model. METHODS Adult female Sprague-Dawley rats underwent a standardized ONC and either received an intravitreal injection of TA (TA group) or of phosphate-buffered saline (PBS, PBS group) in the right eyes. At 1, 3, 7, 14 and 28 days after the ONC, the animals were killed. The retinas were examined by immunohistochemistry, light microscopy, Western blot or retrograde labelling of RGCs by fluorogold injected into the superior colliculi. RESULTS The TA group as compared to the PBS control group showed a significantly (p < 0.0001) lower density of activated RMGCs, at 14 days [4.2 ± 1.6 versus 9.3 ± 2.2 cells/high-power microscopic field (HPF)] and at 28 days (2.3 ± 1.1 versus 4.4 ± 1.5 cells/HPF), and with a significantly lower expression of inflammatory factors. Central density of RGCs as stained by haematoxylin-eosin or by fluorogold was significantly (all p < 0.05) more reduced in the PBS group than in the TA group at days 14 and 28 after baseline. The survival rate (cell density in the study eye as compared to cell density in the contralateral unaffected eye) was significantly higher in the TA group than in the PBS group on days 14 (58% versus 45%; p = 0.003) and 28 (52% versus 41%; p = 0.022). CONCLUSIONS Intravitreal TA as compared to intravitreal PBS was associated with a lower density of activated RMGCs and a higher density of surviving RGCs in an ONC model.
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Affiliation(s)
- Jiawei Wang
- State Key Laboratory of Ophthalmology; Zhongshan Ophthalmic Center; Sun Yat-Sen University; Guangzhou China
| | - Shida Chen
- State Key Laboratory of Ophthalmology; Zhongshan Ophthalmic Center; Sun Yat-Sen University; Guangzhou China
| | - Xiulan Zhang
- State Key Laboratory of Ophthalmology; Zhongshan Ophthalmic Center; Sun Yat-Sen University; Guangzhou China
| | - Wenbin Huang
- State Key Laboratory of Ophthalmology; Zhongshan Ophthalmic Center; Sun Yat-Sen University; Guangzhou China
| | - Jost B. Jonas
- Department of Ophthalmology; Medical Faculty Mannheim of the Ruprecht-Karls-University; Heidelberg Germany
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20
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Carbon monoxide treatment reduces microglial activation in the ischemic rat retina. Graefes Arch Clin Exp Ophthalmol 2016; 254:1967-1976. [PMID: 27443355 DOI: 10.1007/s00417-016-3435-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 06/06/2016] [Accepted: 07/04/2016] [Indexed: 12/21/2022] Open
Abstract
PURPOSE Ischemia and reperfusion (I/R) injury damages retinal neurons. Retinal injury is accompanied by activation of microglia, which scavenge the dead or dying neurons, but increasing evidence now indicates that amoeboid-shaped microglia cells activated in the brain after ischemia have neurotoxic and damaging properties in their own right. A previous study showed that postconditioning with carbon monoxide (CO) protects retinal ganglion cells (RGCs) after I/R through anti-apoptotic and anti-inflammatory mechanisms. The present study was designed to investigate and quantify the activation of retinal microglia after I/R with and without CO postconditioning. METHODS Adult Sprague-Dawley rats underwent retinal ischemia by increasing the ocular pressure to 120 mmHg for 1 h through a needle inserted into the anterior chamber. Reperfusion was induced by removing the needle. After I/R, one group of animals was kept in a CO (250 ppm) atmosphere for 1 h; the other group was kept in room air (Air). At 1, 2, 3, and 7 days after I/R, the eyes were enucleated and fixed. Intracardiac blood was analyzed for systemic effects of CO or I/R. Retinal cross sections were taken from the middle third of the eye and were stained with anti-Iba-1. Microglia cells were graded as amoeboid or ramified phenotypes according to morphologic criteria. Retinal thicknesses were determined. RESULTS Evaluation of retinal tissue revealed a significant reduction of amoeboid microglia cells after I/R + CO when compared to the I/R + Air group. The peak number of amoeboid microglia was observed at day 2 post-I/R + Air. This rise was attenuated by CO postconditioning (815 versus 572 cells/mm2 for I/R + Air versus I/R + CO, respectively; p = 0.005). CO reduced and further postponed the peak in the numbers of amoeboid and ramified microglia cells in ischemic eyes and prevented microglial activation in the contralateral eyes. I/R-induced leucocytosis was inhibited by CO inhalation. The reduction of retinal thickness after I/R was more serious after Air inhalation when compared to the CO group. CONCLUSIONS Numerous activated microglia cells appear in the inner retina after I/R, and CO-treatment significantly attenuates this glial response. Antagonism of microglial activation may be a further neuroprotective effect of CO, apart from its direct anti-apoptotic capacity.
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Hedberg-Buenz A, Christopher MA, Lewis CJ, Fernandes KA, Dutca LM, Wang K, Scheetz TE, Abràmoff MD, Libby RT, Garvin MK, Anderson MG. Quantitative measurement of retinal ganglion cell populations via histology-based random forest classification. Exp Eye Res 2016; 146:370-385. [PMID: 26474494 PMCID: PMC4841761 DOI: 10.1016/j.exer.2015.09.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 09/02/2015] [Accepted: 09/20/2015] [Indexed: 01/27/2023]
Abstract
The inner surface of the retina contains a complex mixture of neurons, glia, and vasculature, including retinal ganglion cells (RGCs), the final output neurons of the retina and primary neurons that are damaged in several blinding diseases. The goal of the current work was two-fold: to assess the feasibility of using computer-assisted detection of nuclei and random forest classification to automate the quantification of RGCs in hematoxylin/eosin (H&E)-stained retinal whole-mounts; and if possible, to use the approach to examine how nuclear size influences disease susceptibility among RGC populations. To achieve this, data from RetFM-J, a semi-automated ImageJ-based module that detects, counts, and collects quantitative data on nuclei of H&E-stained whole-mounted retinas, were used in conjunction with a manually curated set of images to train a random forest classifier. To test performance, computer-derived outputs were compared to previously published features of several well-characterized mouse models of ophthalmic disease and their controls: normal C57BL/6J mice; Jun-sufficient and Jun-deficient mice subjected to controlled optic nerve crush (CONC); and DBA/2J mice with naturally occurring glaucoma. The result of these efforts was development of RetFM-Class, a command-line-based tool that uses data output from RetFM-J to perform random forest classification of cell type. Comparative testing revealed that manual and automated classifications by RetFM-Class correlated well, with 83.2% classification accuracy for RGCs. Automated characterization of C57BL/6J retinas predicted 54,642 RGCs per normal retina, and identified a 48.3% Jun-dependent loss of cells at 35 days post CONC and a 71.2% loss of RGCs among 16-month-old DBA/2J mice with glaucoma. Output from automated analyses was used to compare nuclear area among large numbers of RGCs from DBA/2J mice (n = 127,361). In aged DBA/2J mice with glaucoma, RetFM-Class detected a decrease in median and mean nucleus size of cells classified into the RGC category, as did an independent confirmation study using manual measurements of nuclear area demarcated by BRN3A-immunoreactivity. In conclusion, we have demonstrated that histology-based random forest classification is feasible and can be utilized to study RGCs in a high-throughput fashion. Despite having some limitations, this approach demonstrated a significant association between the size of the RGC nucleus and the DBA/2J form of glaucoma.
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Affiliation(s)
- Adam Hedberg-Buenz
- VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA; Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA
| | - Mark A Christopher
- Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Carly J Lewis
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA
| | - Kimberly A Fernandes
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Laura M Dutca
- VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - Kai Wang
- Department of Biostatistics, University of Iowa, Iowa City, IA 52242, USA
| | - Todd E Scheetz
- Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - Michael D Abràmoff
- VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA; Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA 52242, USA; Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Richard T Libby
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Mona K Garvin
- VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA; Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Michael G Anderson
- VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA; Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA 52242, USA.
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Mac Nair CE, Schlamp CL, Montgomery AD, Shestopalov VI, Nickells RW. Retinal glial responses to optic nerve crush are attenuated in Bax-deficient mice and modulated by purinergic signaling pathways. J Neuroinflammation 2016; 13:93. [PMID: 27126275 PMCID: PMC4850653 DOI: 10.1186/s12974-016-0558-y] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 04/20/2016] [Indexed: 01/14/2023] Open
Abstract
Background Retinal ganglion cell (RGC) soma death is a consequence of optic nerve damage, including in optic neuropathies like glaucoma. The activation of the innate immune network in the retina after nerve damage has been linked to RGC pathology. Since the eye is immune privileged, innate immune functions are the responsibility of the glia, specifically the microglia, astrocytes, and Müller cells that populate the retina. Glial activation, leading to the production of inflammatory cytokines, is a hallmark feature of retinal injury resulting from optic nerve damage and purported to elicit secondary degeneration of RGC somas. Methods A mouse model of optic nerve crush (ONC) was used to study retinal glial activation responses. RGC apoptosis was blocked using Bax-deficient mice. Glial activation responses were monitored by quantitative PCR and immunofluorescent labeling in retinal sections of activation markers. ATP signaling pathways were interrogated using P2X receptor agonists and antagonists and Pannexin 1 (Panx1)-deficient mice with RGC-specific deletion. Results ONC induced activation of both macroglia and microglia in the retina, and both these responses were dramatically muted if RGC death was blocked by deletion of the Bax gene. Macroglial, but not microglial, activation was modulated by purinergic receptor activation. Release of ATP after optic nerve damage was not mediated by PANX1 channels in RGCs. Conclusions RGC death in response to ONC plays a principal stimulatory role in the retinal glial activation response. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0558-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Caitlin E Mac Nair
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, 571A Medical Sciences-1300 University Ave, Madison, WI, 53706, USA.,Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, 3170-10K/L MFCB, 1685 Highland Avenue, Madison, WI, 53705, USA
| | - Cassandra L Schlamp
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, 571A Medical Sciences-1300 University Ave, Madison, WI, 53706, USA
| | - Angela D Montgomery
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, 571A Medical Sciences-1300 University Ave, Madison, WI, 53706, USA
| | - Valery I Shestopalov
- Department of Ophthalmology, University of Miami Miller School of Medicine, 900 N.W. 17th Street, Miami, FL, 33136, USA.,Department of Cell Biology and Anatomy, University of Miami Miller School of Medicine, 900 N.W. 17th Street, Miami, FL, 33136, USA
| | - Robert W Nickells
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, 571A Medical Sciences-1300 University Ave, Madison, WI, 53706, USA.
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Puyang Z, Feng L, Chen H, Liang P, Troy JB, Liu X. Retinal Ganglion Cell Loss is Delayed Following Optic Nerve Crush in NLRP3 Knockout Mice. Sci Rep 2016; 6:20998. [PMID: 26893104 PMCID: PMC4759563 DOI: 10.1038/srep20998] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 01/15/2016] [Indexed: 12/21/2022] Open
Abstract
The NLRP3 inflammasome, a sensor for a variety of pathogen- and host-derived threats, consists of the adaptor ASC (Apoptosis-associated Speck-like protein containing a Caspase Activation and Recruitment Domain (CARD)), pro-caspase-1, and NLRP3 (NOD-Like Receptor family Pyrin domain containing 3). NLRP3-induced neuroinflammation is implicated in the pathogenesis and progression of eye diseases, but it remains unclear whether activation of NLRP3 inflammasome contributes to retinal ganglion cell (RGC) death. Here we examined NLRP3-induced neuroinflammation and RGC survival following partial optic nerve crush (pONC) injury. We showed that NLRP3 was up-regulated in retinal microglial cells following pONC, propagating from the injury site to the optic nerve head and finally the entire retina within one day. Activation of NLRP3-ASC inflammasome led to the up-regulation of caspase-1 and a proinflammatory cytokine, interleukin-1β (IL-1β). In NLRP3 knockout mice, up-regulation of ASC, caspase-1, and IL-1β were all reduced, and, importantly, RGC and axon loss was substantially delayed following pONC injury. The average survival time of RGCs in NLRP3 knockout mice was about one week longer than for control animals. Taken together, our study demonstrated that ablating the NLRP3 gene significantly reduced neuroinflammation and delayed RGC loss after optic nerve crush injury.
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Affiliation(s)
- Zhen Puyang
- School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dong-chuan Road, Shanghai 200240, China.,Department of Biomedical Engineering, Robert R. McCormick School of Engineering and Applied Science, Northwestern University, Evanston, Illinois 60208, USA.,Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Liang Feng
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA.,Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, Illinois 60208, USA
| | - Hui Chen
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Peiji Liang
- School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dong-chuan Road, Shanghai 200240, China
| | - John B Troy
- Department of Biomedical Engineering, Robert R. McCormick School of Engineering and Applied Science, Northwestern University, Evanston, Illinois 60208, USA
| | - Xiaorong Liu
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA.,Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, Illinois 60208, USA
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Karperien AL, Jelinek HF. Box-Counting Fractal Analysis: A Primer for the Clinician. SPRINGER SERIES IN COMPUTATIONAL NEUROSCIENCE 2016. [DOI: 10.1007/978-1-4939-3995-4_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Shimouchi A, Yokota H, Ono S, Matsumoto C, Tamai T, Takumi H, Narayanan SP, Kimura S, Kobayashi H, Caldwell RB, Nagaoka T, Yoshida A. Neuroprotective effect of water-dispersible hesperetin in retinal ischemia reperfusion injury. Jpn J Ophthalmol 2015; 60:51-61. [PMID: 26407617 DOI: 10.1007/s10384-015-0415-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 07/31/2015] [Indexed: 12/18/2022]
Abstract
PURPOSE To determine whether water-dispersible hesperetin (WD-Hpt) can prevent degeneration of ganglion cell neurons in the ischemic retina. METHODS Ischemia reperfusion (I/R) injury was induced by increasing the intraocular pressure of mice to 110 mmHg for 40 min. Mice received daily intraperitoneal injections with either normal saline (NS, 0.3 ml/day) or WD-Hpt (0.3 ml, 200 mg/kg/day). Reactive oxygen species (ROS) was assessed by dihydroethidium and nitrotyrosine formation. Inflammation was estimated by microglial morphology in the retina. Lipopolysaccharide (LPS)-stimulated BV-2 cells were used to explore the anti-inflammatory effect of WD-Hpt on activated microglia by quantifying the expression of IL-1β using real-time quantitative reverse transcription-polymerase chain reaction. Ganglion cell loss was assessed by immunohistochemistry of NeuN. Glial activation was quantified with glial fibrillary acidic protein (GFAP) immunoreactivity. Apoptosis was evaluated with a terminal deoxynucleotidyl transferase (TUNEL) assay and immunohistochemistry of cleaved caspase-3. Phosphorylation of extracellular signal-regulated kinase (p-ERK) was surveyed by western blotting. RESULTS WD-Hpt decreased I/R-induced ROS formation. WD-Hpt alleviated microglial activation induced by I/R and reduced mRNA levels of IL-1β in LPS-stimulated BV-2. I/R resulted in a 37% reduction in the number of ganglion cells in the NS-treated mice, whereas the reduction was only 5% in the WD-Hpt-treated mice. In addition, WD-Hpt mitigated the immunoreactivity of GFAP, increased expression of cleaved caspase-3, increased number of TUNEL positive cells and p-ERK after I/R. CONCLUSIONS WD-Hpt protected ganglion cells from I/R injury by inhibiting oxidative stress and modulating cell death signaling. Moreover, WD-Hpt had an anti-inflammatory effect through the suppression of activated microglia.
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Affiliation(s)
- Akito Shimouchi
- Department of Ophthalmology, Asahikawa Medical University, Midorigaoka Higashi 2-1-1-1, Asahikawa, 078-8510, Japan
| | - Harumasa Yokota
- Department of Ophthalmology, Asahikawa Medical University, Midorigaoka Higashi 2-1-1-1, Asahikawa, 078-8510, Japan.
| | - Shinji Ono
- Department of Ophthalmology, Asahikawa Medical University, Midorigaoka Higashi 2-1-1-1, Asahikawa, 078-8510, Japan
| | - Chiemi Matsumoto
- Department of Ophthalmology, Asahikawa Medical University, Midorigaoka Higashi 2-1-1-1, Asahikawa, 078-8510, Japan
| | - Toshihiro Tamai
- Institute of Health Sciences, Ezaki Glico Co., Ltd, Osaka, Japan
| | - Hiroko Takumi
- Institute of Health Sciences, Ezaki Glico Co., Ltd, Osaka, Japan
| | | | - Shoji Kimura
- Division of Immune Pathology, Department of Pathology, Asahikawa Medical University, Asahikawa, Japan
| | - Hiroya Kobayashi
- Division of Immune Pathology, Department of Pathology, Asahikawa Medical University, Asahikawa, Japan
| | - Ruth B Caldwell
- Vascular Biology Center, Georgia Regents University, Augusta, GA, USA
| | - Taiji Nagaoka
- Department of Ophthalmology, Asahikawa Medical University, Midorigaoka Higashi 2-1-1-1, Asahikawa, 078-8510, Japan
| | - Akitoshi Yoshida
- Department of Ophthalmology, Asahikawa Medical University, Midorigaoka Higashi 2-1-1-1, Asahikawa, 078-8510, Japan
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Mac Nair CE, Nickells RW. Neuroinflammation in Glaucoma and Optic Nerve Damage. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 134:343-63. [PMID: 26310164 DOI: 10.1016/bs.pmbts.2015.06.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Glaucoma is a group of optic neuropathies characterized by the degeneration of retinal ganglion cell axons and somas, ultimately preventing light signals in the retina from reaching the brain. Glaucoma is a leading cause of blindness in the world, and treatment options for patients remain limited and minimally efficacious. A number of mechanisms have been linked to glaucomatous pathophysiology. A leading role is now attributed to neuroinflammatory conditions generated by the resident innate immune cells in the optic nerve and retina. Since the eye is immune privileged, the adaptation of these innate immune cells, termed glia, is crucial following trauma. In this chapter, we discuss the mechanisms associated with normal glial function in a healthy eye, and how changes in glial activation can contribute to the process of glaucomatous neurodegeneration in both the optic nerve and retina.
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Affiliation(s)
- Caitlin E Mac Nair
- Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA; Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Robert W Nickells
- Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA.
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Ramírez AI, Salazar JJ, de Hoz R, Rojas B, Gallego BI, Salobrar-García E, Valiente-Soriano FJ, Triviño A, Ramirez JM. Macro- and microglial responses in the fellow eyes contralateral to glaucomatous eyes. PROGRESS IN BRAIN RESEARCH 2015; 220:155-72. [PMID: 26497789 DOI: 10.1016/bs.pbr.2015.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Most studies employing experimental models of unilateral glaucoma have used the normotensive contralateral eye as the normal control. However, some studies have recently reported the activation of the retinal macroglia and microglia in the uninjured eye, suggesting that the eye contralateral to experimental glaucoma should not be used as a control. This review analyzes the studies describing the contralateral findings and discusses some of the routes through which the signals can reach the contralateral eye to initiate the glial reactivation.
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Affiliation(s)
- Ana I Ramírez
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Spain.
| | - Juan J Salazar
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Spain
| | - Rosa de Hoz
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Spain
| | - Blanca Rojas
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Departamento de Oftalmología y ORL, Facultad de Medicina, Universidad Complutense de Madrid, Spain
| | - Beatriz I Gallego
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Universidad Complutense de Madrid, Spain
| | - Elena Salobrar-García
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Universidad Complutense de Madrid, Spain
| | - Francisco J Valiente-Soriano
- Laboratorio de Oftalmología Experimental, Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Spain
| | - Alberto Triviño
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Departamento de Oftalmología y ORL, Facultad de Medicina, Universidad Complutense de Madrid, Spain
| | - José M Ramirez
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Departamento de Oftalmología y ORL, Facultad de Medicina, Universidad Complutense de Madrid, Spain
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Bosco A, Romero CO, Ambati BK, Vetter ML. In vivo dynamics of retinal microglial activation during neurodegeneration: confocal ophthalmoscopic imaging and cell morphometry in mouse glaucoma. J Vis Exp 2015:e52731. [PMID: 25992962 DOI: 10.3791/52731] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Microglia, which are CNS-resident neuroimmune cells, transform their morphology and size in response to CNS damage, switching to an activated state with distinct functions and gene expression profiles. The roles of microglial activation in health, injury and disease remain incompletely understood due to their dynamic and complex regulation in response to changes in their microenvironment. Thus, it is critical to non-invasively monitor and analyze changes in microglial activation over time in the intact organism. In vivo studies of microglial activation have been delayed by technical limitations to tracking microglial behavior without altering the CNS environment. This has been particularly challenging during chronic neurodegeneration, where long-term changes must be tracked. The retina, a CNS organ amenable to non-invasive live imaging, offers a powerful system to visualize and characterize the dynamics of microglia activation during chronic disorders. This protocol outlines methods for long-term, in vivo imaging of retinal microglia, using confocal ophthalmoscopy (cSLO) and CX3CR1(GFP/+) reporter mice, to visualize microglia with cellular resolution. Also, we describe methods to quantify monthly changes in cell activation and density in large cell subsets (200-300 cells per retina). We confirm the use of somal area as a useful metric for live tracking of microglial activation in the retina by applying automated threshold-based morphometric analysis of in vivo images. We use these live image acquisition and analyses strategies to monitor the dynamic changes in microglial activation and microgliosis during early stages of retinal neurodegeneration in a mouse model of chronic glaucoma. This approach should be useful to investigate the contributions of microglia to neuronal and axonal decline in chronic CNS disorders that affect the retina and optic nerve.
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Affiliation(s)
| | - Cesar O Romero
- Department of Neurobiology & Anatomy, University of Utah
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Gao L, Chen X, Tang Y, Zhao J, Li Q, Fan X, Xu H, Yin ZQ. Neuroprotective effect of memantine on the retinal ganglion cells of APPswe/PS1ΔE9 mice and its immunomodulatory mechanisms. Exp Eye Res 2015; 135:47-58. [PMID: 25912193 DOI: 10.1016/j.exer.2015.04.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/20/2015] [Accepted: 04/21/2015] [Indexed: 01/16/2023]
Abstract
Besides the cognitive impairment and degeneration in the brain, vision dysfunction and retina damage are always prevalent in patients with Alzheimer's disease (AD). The uncompetitive antagonist of the N-methyl-d-aspartate receptor, memantine (MEM), has been proven to improve the cognition of patients with AD. However, limited information exists regarding the mechanism of neurodegeneration and the possible neuroprotective mechanisms of MEM on the retinas of patients with AD. In the present study, by using APPswe/PS1ΔE9 double transgenic (dtg) mice, we found that MEM rescued the loss of retinal ganglion cells (RGCs), as well as improved visual impairments, including improving the P50 component in pattern electroretinograms and the latency delay of the P2 component in flash visual evoked potentials of APPswe/PS1ΔE9 dtg mice. The activated microglia in the retinas of APPswe/PS1ΔE9 dtg mice were also inhibited by MEM. Additionally, the level of glutamine synthetase expressed by Müller cells within the RGC layer was upregulated in APPswe/PS1ΔE9 dtg mice, which was inhibited by MEM. Simultaneously, MEM also reduced the apoptosis of choline acetyl transferase-immunoreactive cholinergic amacrine cells within the RGC layer of AD mice. Moreover, the phosphorylation level of extracellular regulated protein kinases 1 and 2 was increased in APPswe/PS1ΔE9 dtg mice, which was blocked by MEM treatment. These findings suggest that MEM protects RGCs in the retinas of APPswe/PS1ΔE9 dtg mice by modulating the immune response of microglia and the adapted response of Müller cells, making MEM a potential ophthalmic treatment alternative in patients with AD.
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Affiliation(s)
- Lixiong Gao
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing 400038, China; Department of Developmental Neuropsychology, School of Psychology, Third Military Medical University, Chongqing 400038, China.
| | - Xi Chen
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing 400038, China; School of Medicine, Nankai University, Tianjin 300071, China; Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing 100853, China.
| | - Yongping Tang
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing 400038, China.
| | - Jinghui Zhao
- Department of Developmental Neuropsychology, School of Psychology, Third Military Medical University, Chongqing 400038, China.
| | - Qiyou Li
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing 400038, China.
| | - Xiaotang Fan
- Department of Developmental Neuropsychology, School of Psychology, Third Military Medical University, Chongqing 400038, China.
| | - Haiwei Xu
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing 400038, China.
| | - Zheng Qin Yin
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing 400038, China.
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Bosco A, Romero CO, Breen KT, Chagovetz AA, Steele MR, Ambati BK, Vetter ML. Neurodegeneration severity can be predicted from early microglia alterations monitored in vivo in a mouse model of chronic glaucoma. Dis Model Mech 2015; 8:443-55. [PMID: 25755083 PMCID: PMC4415894 DOI: 10.1242/dmm.018788] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 02/26/2015] [Indexed: 12/30/2022] Open
Abstract
Microglia serve key homeostatic roles, and respond to neuronal perturbation and decline with a high spatiotemporal resolution. The course of all chronic CNS pathologies is thus paralleled by local microgliosis and microglia activation, which begin at early stages of the disease. However, the possibility of using live monitoring of microglia during early disease progression to predict the severity of neurodegeneration has not been explored. Because the retina allows live tracking of fluorescent microglia in their intact niche, here we investigated their early changes in relation to later optic nerve neurodegeneration. To achieve this, we used the DBA/2J mouse model of inherited glaucoma, which develops progressive retinal ganglion cell degeneration of variable severity during aging, and represents a useful model to study pathogenic mechanisms of retinal ganglion cell decline that are similar to those in human glaucoma. We imaged CX3CR1(+/GFP) microglial cells in vivo at ages ranging from 1 to 5 months by confocal scanning laser ophthalmoscopy (cSLO) and quantified cell density and morphological activation. We detected early microgliosis at the optic nerve head (ONH), where axonopathy first manifests, and could track attenuation of this microgliosis induced by minocycline. We also observed heterogeneous and dynamic patterns of early microglia activation in the retina. When the same animals were aged and analyzed for the severity of optic nerve pathology at 10 months of age, we found a strong correlation with the levels of ONH microgliosis at 3 to 4 months. Our findings indicate that live imaging and monitoring the time course and levels of early retinal microgliosis and microglia activation in glaucoma could serve as indicators of future neurodegeneration severity.
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Affiliation(s)
- Alejandra Bosco
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA
| | - Cesar O Romero
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA
| | - Kevin T Breen
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA
| | - Alexis A Chagovetz
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84132, USA
| | - Michael R Steele
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA
| | - Balamurali K Ambati
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT 84132, USA
| | - Monica L Vetter
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA
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Karlstetter M, Scholz R, Rutar M, Wong WT, Provis JM, Langmann T. Retinal microglia: just bystander or target for therapy? Prog Retin Eye Res 2014; 45:30-57. [PMID: 25476242 DOI: 10.1016/j.preteyeres.2014.11.004] [Citation(s) in RCA: 358] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 11/20/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
Abstract
Resident microglial cells can be regarded as the immunological watchdogs of the brain and the retina. They are active sensors of their neuronal microenvironment and rapidly respond to various insults with a morphological and functional transformation into reactive phagocytes. There is strong evidence from animal models and in situ analyses of human tissue that microglial reactivity is a common hallmark of various retinal degenerative and inflammatory diseases. These include rare hereditary retinopathies such as retinitis pigmentosa and X-linked juvenile retinoschisis but also comprise more common multifactorial retinal diseases such as age-related macular degeneration, diabetic retinopathy, glaucoma, and uveitis as well as neurological disorders with ocular manifestation. In this review, we describe how microglial function is kept in balance under normal conditions by cross-talk with other retinal cells and summarize how microglia respond to different forms of retinal injury. In addition, we present the concept that microglia play a key role in local regulation of complement in the retina and specify aspects of microglial aging relevant for chronic inflammatory processes in the retina. We conclude that this resident immune cell of the retina cannot be simply regarded as bystander of disease but may instead be a potential therapeutic target to be modulated in the treatment of degenerative and inflammatory diseases of the retina.
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Affiliation(s)
- Marcus Karlstetter
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Rebecca Scholz
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Matt Rutar
- The John Curtin School of Medical Research, The Australian National University (ANU), Canberra, Australian Capital Territory, Australia
| | - Wai T Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jan M Provis
- The John Curtin School of Medical Research, The Australian National University (ANU), Canberra, Australian Capital Territory, Australia
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany.
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Choe TE, Abbott CJ, Piper C, Wang L, Fortune B. Comparison of longitudinal in vivo measurements of retinal nerve fiber layer thickness and retinal ganglion cell density after optic nerve transection in rat. PLoS One 2014; 9:e113011. [PMID: 25393294 PMCID: PMC4231142 DOI: 10.1371/journal.pone.0113011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 10/23/2014] [Indexed: 11/23/2022] Open
Abstract
Purpose To determine the relationship between longitudinal in vivo measurements of retinal nerve fiber layer thickness (RNFLT) and retinal ganglion cell (RGC) density after unilateral optic nerve transection (ONT). Methods Nineteen adult Brown-Norway rats were studied; N = 10 ONT plus RGC label, N = 3 ONT plus vehicle only (sans label), N = 6 sham ONT plus RGC label. RNFLT was measured by spectral domain optical coherence tomography (SD-OCT) at baseline then weekly for 1 month. RGCs were labeled by retrograde transport of fluorescently conjugated cholera toxin B (CTB) from the superior colliculus 48 hours prior to ONT or sham surgery. RGC density measurements were obtained by confocal scanning laser ophthalmoscopy (CSLO) at baseline and weekly for 1 month. RGC density and reactivity of microglia (anti-Iba1) and astrocytes (anti-GFAP) were determined from post mortem fluorescence microscopy of whole-mount retinae. Results RNFLT decreased after ONT by 17% (p<0.05), 30% (p<0.0001) and 36% (p<0.0001) at weeks 2, 3 and 4. RGC density decreased after ONT by 18%, 69%, 85% and 92% at weeks 1, 2, 3 and 4 (p<0.0001 each). RGC density measured in vivo at week 4 and post mortem by microscopy were strongly correlated (R = 0.91, p<0.0001). In vivo measures of RNFLT and RGC density were strongly correlated (R = 0.81, p<0.0001). In ONT- CTB labeled fellow eyes, RNFLT increased by 18%, 52% and 36% at weeks 2, 3 and 4 (p<0.0001), but did not change in fellow ONT-eyes sans CTB. Microgliosis was evident in the RNFL of the ONT-CTB fellow eyes, exceeding that observed in other fellow eyes. Conclusions In vivo measurements of RNFLT and RGC density are strongly correlated and can be used to monitor longitudinal changes after optic nerve injury. The strong fellow eye effect observed in eyes contralateral to ONT, only in the presence of CTB label, consisted of a dramatic increase in RNFLT associated with retinal microgliosis.
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Affiliation(s)
- Tiffany E. Choe
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
| | - Carla J. Abbott
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
| | - Chelsea Piper
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
| | - Lin Wang
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
- * E-mail:
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Cuenca N, Fernández-Sánchez L, Campello L, Maneu V, De la Villa P, Lax P, Pinilla I. Cellular responses following retinal injuries and therapeutic approaches for neurodegenerative diseases. Prog Retin Eye Res 2014; 43:17-75. [PMID: 25038518 DOI: 10.1016/j.preteyeres.2014.07.001] [Citation(s) in RCA: 296] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/03/2014] [Accepted: 07/07/2014] [Indexed: 01/17/2023]
Abstract
Retinal neurodegenerative diseases like age-related macular degeneration, glaucoma, diabetic retinopathy and retinitis pigmentosa each have a different etiology and pathogenesis. However, at the cellular and molecular level, the response to retinal injury is similar in all of them, and results in morphological and functional impairment of retinal cells. This retinal degeneration may be triggered by gene defects, increased intraocular pressure, high levels of blood glucose, other types of stress or aging, but they all frequently induce a set of cell signals that lead to well-established and similar morphological and functional changes, including controlled cell death and retinal remodeling. Interestingly, an inflammatory response, oxidative stress and activation of apoptotic pathways are common features in all these diseases. Furthermore, it is important to note the relevant role of glial cells, including astrocytes, Müller cells and microglia, because their response to injury is decisive for maintaining the health of the retina or its degeneration. Several therapeutic approaches have been developed to preserve retinal function or restore eyesight in pathological conditions. In this context, neuroprotective compounds, gene therapy, cell transplantation or artificial devices should be applied at the appropriate stage of retinal degeneration to obtain successful results. This review provides an overview of the common and distinctive features of retinal neurodegenerative diseases, including the molecular, anatomical and functional changes caused by the cellular response to damage, in order to establish appropriate treatments for these pathologies.
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Affiliation(s)
- Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain; Multidisciplinary Institute for Environmental Studies "Ramon Margalef", University of Alicante, Alicante, Spain.
| | - Laura Fernández-Sánchez
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Laura Campello
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Victoria Maneu
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Pedro De la Villa
- Department of Systems Biology, University of Alcalá, Alcalá de Henares, Spain
| | - Pedro Lax
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Isabel Pinilla
- Department of Ophthalmology, Lozano Blesa University Hospital, Aragon Institute of Health Sciences, Zaragoza, Spain
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Lindsey JD, Duong-Polk KX, Dai Y, Nguyen DH, Leung CK, Weinreb RN. Protection by an oral disubstituted hydroxylamine derivative against loss of retinal ganglion cell differentiation following optic nerve crush. PLoS One 2013; 8:e65966. [PMID: 23940507 PMCID: PMC3734221 DOI: 10.1371/journal.pone.0065966] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 05/01/2013] [Indexed: 11/19/2022] Open
Abstract
Thy-1 is a cell surface protein that is expressed during the differentiation of retinal ganglion cells (RGCs). Optic nerve injury induces progressive loss in the number of RGCs expressing Thy-1. The rate of this loss is fastest during the first week after optic nerve injury and slower in subsequent weeks. This study was undertaken to determine whether oral treatment with a water-soluble N-hydroxy-2,2,6,6-tetramethylpiperidine derivative (OT-440) protects against loss of Thy-1 promoter activation following optic nerve crush and whether this effect targets the earlier quick phase or the later slow phase. The retina of mice expressing cyan fluorescent protein under control of the Thy-1 promoter (Thy1-CFP mice) was imaged using a blue-light confocal scanning laser ophthalmoscope (bCSLO). These mice then received oral OT-440 prepared in cream cheese or dissolved in water, or plain vehicle, for two weeks and were imaged again prior to unilateral optic nerve crush. Treatments and weekly imaging continued for four more weeks. Fluorescent neurons were counted in the same defined retinal areas imaged at each time point in a masked fashion. When the counts at each time point were directly compared, the numbers of fluorescent cells at each time point were greater in the animals that received OT-440 in cream cheese by 8%, 27%, 52% and 60% than in corresponding control animals at 1, 2, 3 and 4 weeks after optic nerve crush. Similar results were obtained when the vehicle was water. Rate analysis indicated the protective effect of OT-440 was greatest during the first two weeks and was maintained in the second two weeks after crush for both the cream cheese vehicle study and water vehicle study. Because most of the fluorescent cells detected by bCSLO are RGCs, these findings suggest that oral OT-440 can either protect against or delay early degenerative responses occurring in RGCs following optic nerve injury.
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Affiliation(s)
- James D Lindsey
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California San Diego, La Jolla, California, USA.
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Retinal ganglion cell dendritic degeneration in a mouse model of Alzheimer's disease. Neurobiol Aging 2013; 34:1799-806. [DOI: 10.1016/j.neurobiolaging.2013.01.006] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 01/11/2013] [Accepted: 01/11/2013] [Indexed: 12/30/2022]
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Karperien A, Ahammer H, Jelinek HF. Quantitating the subtleties of microglial morphology with fractal analysis. Front Cell Neurosci 2013; 7:3. [PMID: 23386810 PMCID: PMC3558688 DOI: 10.3389/fncel.2013.00003] [Citation(s) in RCA: 312] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 01/08/2013] [Indexed: 01/17/2023] Open
Abstract
It is well established that microglial form and function are inextricably linked. In recent years, the traditional view that microglial form ranges between “ramified resting” and “activated amoeboid” has been emphasized through advancing imaging techniques that point to microglial form being highly dynamic even within the currently accepted morphological categories. Moreover, microglia adopt meaningful intermediate forms between categories, with considerable crossover in function and varying morphologies as they cycle, migrate, wave, phagocytose, and extend and retract fine and gross processes. From a quantitative perspective, it is problematic to measure such variability using traditional methods, but one way of quantitating such detail is through fractal analysis. The techniques of fractal analysis have been used for quantitating microglial morphology, to categorize gross differences but also to differentiate subtle differences (e.g., amongst ramified cells). Multifractal analysis in particular is one technique of fractal analysis that may be useful for identifying intermediate forms. Here we review current trends and methods of fractal analysis, focusing on box counting analysis, including lacunarity and multifractal analysis, as applied to microglial morphology.
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Affiliation(s)
- Audrey Karperien
- Centre for Research in Complex Systems, School of Community Health, Charles Sturt University Albury, NSW, Australia
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