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Ghena N, Anderson SR, Roberts JM, Irvin E, Schwakopf J, Bosco A, Vetter ML. CD11c-expressing microglia are transient, driven by interactions with apoptotic cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.24.600082. [PMID: 38979153 PMCID: PMC11230207 DOI: 10.1101/2024.06.24.600082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Microglia, the parenchymal macrophage of the central nervous system serve crucial remodeling functions throughout development. Microglia are transcriptionally heterogenous, suggesting that distinct microglial states confer discrete roles. Currently, little is known about how dynamic these states are, the cues that promote them, or how they impact microglial function. In the developing retina, we previously found a significant proportion of microglia express CD11c (Integrin αX, complement receptor 4, Itgax) which has also been reported in other developmental and disease contexts. Here, we sought to understand the regulation and function of CD11c+ microglia. We found that CD11c+ microglia track with prominent waves of neuronal apoptosis in postnatal retina. Using genetic fate mapping, we provide evidence that microglia transition out of the CD11c state to return to homeostasis. We show that CD11c+ microglia have elevated lysosomal content and contribute to the clearance of apoptotic neurons, and found that acquisition of CD11c expression is, in part, dependent upon the TAM receptor Axl. Using selective ablation, we found CD11c+ microglia are not uniquely critical for phagocytic clearance of apoptotic cells. Together, our data suggest CD11c+ microglia are a transient state induced by developmental apoptosis rather than a specialized subset mediating phagocytic elimination.
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Affiliation(s)
- Nathaniel Ghena
- Department of Neurobiology, University of Utah School of Medicine
- Interdepartmental Program in Neuroscience, University of Utah
| | - Sarah R Anderson
- Department of Neurobiology, University of Utah School of Medicine
| | | | - Emmalyn Irvin
- Department of Neurobiology, University of Utah School of Medicine
| | - Joon Schwakopf
- Department of Neurobiology, University of Utah School of Medicine
| | - Alejandra Bosco
- Department of Neurobiology, University of Utah School of Medicine
| | - Monica L Vetter
- Department of Neurobiology, University of Utah School of Medicine
- Interdepartmental Program in Neuroscience, University of Utah
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2
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Ruiz-Pastor MJ, Sánchez-Sáez X, Kutsyr O, Albertos-Arranz H, Sánchez-Castillo C, Ortuño-Lizarán I, Martínez-Gil N, Vidal-Gil L, Méndez L, Sánchez-Martín M, Maneu V, Lax P, Cuenca N. Prph2 knock-in mice recapitulate human central areolar choroidal dystrophy retinal degeneration and exhibit aberrant synaptic remodeling and microglial activation. Cell Death Dis 2023; 14:711. [PMID: 37914688 PMCID: PMC10620171 DOI: 10.1038/s41419-023-06243-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/16/2023] [Accepted: 10/20/2023] [Indexed: 11/03/2023]
Abstract
Central areolar choroidal dystrophy is an inherited disorder characterized by progressive choriocapillaris atrophy and retinal degeneration and is usually associated with mutations in the PRPH2 gene. We aimed to generate and characterize a mouse model with the p.Arg195Leu mutation previously described in patients. Heterozygous (Prph2WT/KI) and homozygous (Prph2KI/KI) mice were generated using the CRISPR/Cas9 system to introduce the p.Arg195Leu mutation. Retinal function was assessed by electroretinography and optomotor tests at 1, 3, 6, 9, 12, and 20 months of age. The structural integrity of the retinas was evaluated at the same ages using optical coherence tomography. Immunofluorescence and transmission electron microscopy images of the retina were also analyzed. Genetic sequencing confirmed that both Prph2WT/KI and Prph2KI/KI mice presented the p.Arg195Leu mutation. A progressive loss of retinal function was found in both mutant groups, with significantly reduced visual acuity from 3 months of age in Prph2KI/KI mice and from 6 months of age in Prph2WT/KI mice. Decreased amplitudes in the electroretinography responses were observed from 1 month of age in Prph2KI/KI mice and from 6 months of age in Prph2WT/KI mice. Morphological analysis of the retinas correlated with functional findings, showing a progressive decrease in retinal thickness of mutant mice, with earlier and more severe changes in the homozygous mutant mice. We corroborated the alteration of the outer segment structure, and we found changes in the synaptic connectivity in the outer plexiform layer as well as gliosis and signs of microglial activation. The new Prph2WT/KI and Prph2KI/KI murine models show a pattern of retinal degeneration similar to that described in human patients with central areolar choroidal dystrophy and appear to be good models to study the mechanisms involved in the onset and progression of the disease, as well as to test the efficacy of new therapeutic strategies.
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Affiliation(s)
| | - Xavier Sánchez-Sáez
- Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain
| | - Oksana Kutsyr
- Optics, Pharmacology, and Anatomy, University of Alicante, Alicante, Spain
| | | | | | | | | | - Lorena Vidal-Gil
- Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain
| | - Lucía Méndez
- Transgenic Facility and Department of Medicine, University of Salamanca, Salamanca, Spain
| | - Manuel Sánchez-Martín
- Transgenic Facility and Department of Medicine, University of Salamanca, Salamanca, Spain
- Institute for Biomedical Research of Salamanca (IBSAL), Salamanca, Spain
| | - Victoria Maneu
- Optics, Pharmacology, and Anatomy, University of Alicante, Alicante, Spain
- Alicante Institute for Health and Biomedical Research (ISABIAL), Alicante, Spain
| | - Pedro Lax
- Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain.
- Alicante Institute for Health and Biomedical Research (ISABIAL), Alicante, Spain.
| | - Nicolás Cuenca
- Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain.
- Alicante Institute for Health and Biomedical Research (ISABIAL), Alicante, Spain.
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3
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Maes ME, Colombo G, Schoot Uiterkamp FE, Sternberg F, Venturino A, Pohl EE, Siegert S. Mitochondrial network adaptations of microglia reveal sex-specific stress response after injury and UCP2 knockout. iScience 2023; 26:107780. [PMID: 37731609 PMCID: PMC10507162 DOI: 10.1016/j.isci.2023.107780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/10/2023] [Accepted: 08/28/2023] [Indexed: 09/22/2023] Open
Abstract
Mitochondrial networks remodel their connectivity, content, and subcellular localization to support optimized energy production in conditions of increased environmental or cellular stress. Microglia rely on mitochondria to respond to these stressors, however our knowledge about mitochondrial networks and their adaptations in microglia in vivo is limited. Here, we generate a mouse model that selectively labels mitochondria in microglia. We identify that mitochondrial networks are more fragmented with increased content and perinuclear localization in vitro vs. in vivo. Mitochondrial networks adapt similarly in microglia closest to the injury site after optic nerve crush. Preventing microglial UCP2 increase after injury by selective knockout induces cellular stress. This results in mitochondrial hyperfusion in male microglia, a phenotype absent in females due to circulating estrogens. Our results establish the foundation for mitochondrial network analysis of microglia in vivo, emphasizing the importance of mitochondrial-based sex effects of microglia in other pathologies.
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Affiliation(s)
- Margaret E. Maes
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Gloria Colombo
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | | | - Felix Sternberg
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria
| | - Alessandro Venturino
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Elena E. Pohl
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria
| | - Sandra Siegert
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
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4
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Khan AH, Chowers I, Lotery AJ. Beyond the Complement Cascade: Insights into Systemic Immunosenescence and Inflammaging in Age-Related Macular Degeneration and Current Barriers to Treatment. Cells 2023; 12:1708. [PMID: 37443742 PMCID: PMC10340338 DOI: 10.3390/cells12131708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 06/22/2023] [Accepted: 06/22/2023] [Indexed: 07/15/2023] Open
Abstract
Landmark genetic studies have revealed the effect of complement biology and its regulation on the pathogenesis of age-related macular degeneration (AMD). Limited phase 3 clinical trial data showing a benefit of complement inhibition in AMD raises the prospect of more complex mediators at play. Substantial evidence supports the role of para-inflammation in maintaining homeostasis in the retina and choroid. With increasing age, a decline in immune system regulation, known as immunosenescence, has been shown to alter the equilibrium maintained by para-inflammation. The altered equilibrium results in chronic, sterile inflammation with aging, termed 'inflammaging', including in the retina and choroid. The chronic inflammatory state in AMD is complex, with contributions from cells of the innate and adaptive branches of the immune system, sometimes with overlapping features, and the interaction of their secretory products with retinal cells such as microglia and retinal pigment epithelium (RPE), extracellular matrix and choroidal vascular endothelial cells. In this review, the chronic inflammatory state in AMD will be explored by immune cell type, with a discussion of factors that will need to be overcome in the development of curative therapies.
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Affiliation(s)
- Adnan H. Khan
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO17 1BJ, UK
- Southampton Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
| | - Itay Chowers
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
- Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91121, Israel
| | - Andrew J. Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO17 1BJ, UK
- Southampton Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
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5
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Ascunce K, Dhodapkar RM, Huang D, Hafler BP. Innate immune biology in age-related macular degeneration. Front Cell Dev Biol 2023; 11:1118524. [PMID: 36926522 PMCID: PMC10011475 DOI: 10.3389/fcell.2023.1118524] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 02/06/2023] [Indexed: 03/08/2023] Open
Abstract
Age-related macular degeneration (AMD) is a neurodegenerative disease and a leading cause of irreversible vision loss in the developed world. While not classically described as an inflammatory disease, a growing body of evidence has implicated several components of the innate immune system in the pathophysiology of age-related macular degeneration. In particular, complement activation, microglial involvement, and blood-retinal-barrier disruption have been shown to play key roles in disease progression, and subsequent vision loss. This review discusses the role of the innate immune system in age-related macular degeneration as well as recent developments in single-cell transcriptomics that help advance the understanding and treatment of age-related macular degeneration. We also explore the several potential therapeutic targets for age-related macular degeneration in the context of innate immune activation.
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Affiliation(s)
- Karina Ascunce
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, United States
| | - Rahul M Dhodapkar
- Department of Ophthalmology, Roski Eye Institute, University of Southern California, Los Angeles, California
| | - Deven Huang
- Choate Rosemary Hall, Wallingford, CT, United States
| | - Brian P Hafler
- Department of Ophthalmology and Visual Science, Yale University, New Haven, CT, United States.,Department of Pathology, Yale University, New Haven, CT, United States
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McPherson SW, Heuss ND, Abedin M, Roehrich H, Pierson MJ, Gregerson DS. Parabiosis reveals the correlation between the recruitment of circulating antigen presenting cells to the retina and the induction of spontaneous autoimmune uveoretinitis. J Neuroinflammation 2022; 19:295. [PMID: 36494807 PMCID: PMC9733026 DOI: 10.1186/s12974-022-02660-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 11/29/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Characterizing immune cells and conditions that govern their recruitment and function in autoimmune diseases of the nervous system or in neurodegenerative processes is an area of active investigation. We sought to analyze the origin of antigen presenting cells associated with the induction of retinal autoimmunity using a system that relies on spontaneous autoimmunity, thus avoiding uncertainties associated with immunization with adjuvants at remotes sites or adoptive transfer of in vitro activated T cells. METHODS R161H mice (B10.RIII background), which spontaneously and rapidly develop severe spontaneous autoimmune uveoretinitis (SAU), were crossed to CD11cDTR/GFP mice (B6/J) allowing us to track the recruitment to and/or expansion within the retina of activated, antigen presenting cells (GFPhi cells) in R161H+/- × CD11cDTR/GFP F1 mice relative to the course of SAU. Parabiosis between R161H+/- × CD11cDTR/GFP F1 mice and B10.RIII × B6/J F1 (wild-type recipient) mice was done to explore the origin and phenotype of antigen presenting cells crucial for the induction of autoimmunity. Analysis was done by retinal imaging, flow cytometry, and histology. RESULTS Onset of SAU in R161H+/- × CD11cDTR/GFP F1 mice was delayed relative to B10.RIII-R161H+/- mice revealing a disease prophase prior to frank autoimmunity that was characterized by expansion of GFPhi cells within the retina prior to any clinical or histological evidence of autoimmunity. Parabiosis between mice carrying the R161H and CD11cDTR/GFP transgenes and transgene negative recipients showed that recruitment of circulating GFPhi cells into retinas was highly correlative with the occurrence of SAU. CONCLUSIONS Our results here contrast with our previous findings showing that retinal antigen presenting cells expanding in response to either sterile mechanical injury or neurodegeneration were derived from myeloid cells within the retina or optic nerve, thus highlighting a unique facet of retinal autoimmunity.
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Affiliation(s)
- Scott W. McPherson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, 2001 6th Street SE, Lions Research Building, Room 482A, Minneapolis, MN 55455 USA
| | - Neal D. Heuss
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, 2001 6th Street SE, Lions Research Building, Room 482A, Minneapolis, MN 55455 USA
| | - Md. Abedin
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, 2001 6th Street SE, Lions Research Building, Room 482A, Minneapolis, MN 55455 USA
| | - Heidi Roehrich
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, 2001 6th Street SE, Lions Research Building, Room 482A, Minneapolis, MN 55455 USA
| | - Mark J. Pierson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, 2001 6th Street SE, Lions Research Building, Room 482A, Minneapolis, MN 55455 USA
| | - Dale S. Gregerson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, 2001 6th Street SE, Lions Research Building, Room 482A, Minneapolis, MN 55455 USA
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7
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Szczepan M, Llorián-Salvador M, Chen M, Xu H. Immune Cells in Subretinal Wound Healing and Fibrosis. Front Cell Neurosci 2022; 16:916719. [PMID: 35755781 PMCID: PMC9226489 DOI: 10.3389/fncel.2022.916719] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 05/16/2022] [Indexed: 11/22/2022] Open
Abstract
The subretinal space is devoid of any immune cells under normal conditions and is an immune privileged site. When photoreceptors and/or retinal pigment epithelial cells suffer from an injury, a wound healing process will be initiated. Retinal microglia and the complement system, as the first line of retinal defense, are activated to participate in the wound healing process. If the injury is severe or persists for a prolonged period, they may fail to heal the damage and circulating immune cells will be summoned leading to chronic inflammation and abnormal wound healing, i.e., subretinal or intraretinal fibrosis, a sight-threatening condition frequently observed in rhematogenous retinal detachment, age-related macular degeneration and recurrent uveoretinitis. Here, we discussed the principles of subretinal wound healing with a strong focus on the conditions whereby the damage is beyond the healing capacity of the retinal defense system and highlighted the roles of circulating immune cells in subretinal wound healing and fibrosis.
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Affiliation(s)
- Manon Szczepan
- The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | - María Llorián-Salvador
- The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | - Mei Chen
- The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | - Heping Xu
- The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom,Aier Institute of Optometry and Vision Science, Changsha, China,*Correspondence: Heping Xu,
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8
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Molecular regulation of neuroinflammation in glaucoma: Current knowledge and the ongoing search for new treatment targets. Prog Retin Eye Res 2022; 87:100998. [PMID: 34348167 PMCID: PMC8803988 DOI: 10.1016/j.preteyeres.2021.100998] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 12/11/2022]
Abstract
Neuroinflammation relying on the inflammatory responses of glial cells has emerged as an impactful component of the multifactorial etiology of neurodegeneration in glaucoma. It has become increasingly evident that despite early adaptive and reparative features of glial responses, prolonged reactivity of the resident glia, along with the peripheral immune cells, create widespread toxicity to retinal ganglion cell (RGC) axons, somas, and synapses. As much as the synchronized responses of astrocytes and microglia to glaucoma-related stress or neuron injury, their bi-directional interactions are critical to build and amplify neuroinflammation and to dictate the neurodegenerative outcome. Although distinct molecular programs regulate somatic and axonal degeneration in glaucoma, inhibition of neurodegenerative inflammation can provide a broadly beneficial treatment strategy to rescue RGC integrity and function. Since inflammatory toxicity and mitochondrial dysfunction are converging etiological paths that can boost each other and feed into a vicious cycle, anti-inflammatory treatments may also offer a multi-target potential. This review presents an overview of the current knowledge on neuroinflammation in glaucoma with particular emphasis on the cell-intrinsic and cell-extrinsic factors involved in the reciprocal regulation of glial responses, the interdependence between inflammatory and mitochondrial routes of neurodegeneration, and the research aspects inspiring for prospective immunomodulatory treatments. With the advent of powerful technologies, ongoing research on molecular and functional characteristics of glial responses is expected to accumulate more comprehensive and complementary information and to rapidly move the field forward to safe and effective modulation of the glial pro-inflammatory activities, while restoring or augmenting the glial immune-regulatory and neurosupport functions.
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9
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Lucas-Ruiz F, Galindo-Romero C, Albaladejo-García V, Vidal-Sanz M, Agudo-Barriuso M. Mechanisms implicated in the contralateral effect in the central nervous system after unilateral injury: focus on the visual system. Neural Regen Res 2021; 16:2125-2131. [PMID: 33818483 PMCID: PMC8354113 DOI: 10.4103/1673-5374.310670] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 11/21/2020] [Accepted: 01/11/2021] [Indexed: 12/21/2022] Open
Abstract
The retina, as part of the central nervous system is an ideal model to study the response of neurons to injury and disease and to test new treatments. During the last decade is becoming clear that unilateral lesions in bilateral areas of the central nervous system trigger an inflammatory response in the contralateral uninjured site. This effect has been better studied in the visual system where, as a rule, one retina is used as experimental and the other as control. Contralateral retinas in unilateral models of retinal injury show neuronal degeneration and glial activation. The mechanisms by which this adverse response in the central nervous system occurs are discussed in this review, focusing primarily on the visual system.
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Affiliation(s)
- Fernando Lucas-Ruiz
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIBArrixaca) Murcia, Spain
| | - Caridad Galindo-Romero
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIBArrixaca) Murcia, Spain
| | - Virginia Albaladejo-García
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIBArrixaca) Murcia, Spain
| | - Manuel Vidal-Sanz
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIBArrixaca) Murcia, Spain
| | - Marta Agudo-Barriuso
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIBArrixaca) Murcia, Spain
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Yang P, Chen L, Shi Y, Zhou F, Tian H, Li J, Gao L. Progesterone alters the activation and typing of the microglia in the optic nerve crush model. Exp Eye Res 2021; 212:108805. [PMID: 34699875 DOI: 10.1016/j.exer.2021.108805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 10/18/2021] [Accepted: 10/21/2021] [Indexed: 12/21/2022]
Abstract
Microglia have a protective effect on the central nervous system (CNS), but their over-proliferation can cause secondary injury to the retina following optic nerve crush (ONC). Progesterone as a steroid gonadal hormone has been used in some experimental animal models for its neuroprotective effect. However, there is limited attention on the interactions between progesterone and microglia in retinal diseases. This study investigated the proliferation, morphology changes, and cell types of microglia at 3 days and 7 days after ONC. We found that progesterone treatment in unilateral optic nerve injury mice significantly reduced densities and morphological change of microglia at 7 days in the ganglion cell layer (GCL), especially in the retinal central. Inhibition of the microglia proliferation and transformation of ramified microglia into ameboid macrophages also appeared in the inner plexiform layer (IPL). Moreover, progesterone also regulated the TNF signal pathway, which was similar to the specific elimination of the M1 phenotype. M1 marks such as tumor necrosis factor alpha (TNF-α), inducible NOS(iNOS), interleukin-6 (IL-6), and Fc receptor (CD16 and CD32) significantly downregulated by progesterone treatment whether at 3 days or 7 days after ONC. On the other hand, progesterone continuously increased the expression of the M2 marks, including interleukin-4 (IL-4), arginase 1 (Arg1), and mannose receptor (CD206) since the third day, while the expression levels of transforming growth factor (TGF-β) only increased at 7 days. In general, this study elucidated the mechanism that progesterone prevented further damage on the retina by inhibiting proliferation, activation, and changing the type of microglia.
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Affiliation(s)
- Pengfei Yang
- School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Linchi Chen
- School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Yongpeng Shi
- School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Fangfang Zhou
- College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China
| | - Huanbing Tian
- School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Jiande Li
- School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Lan Gao
- School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
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Hargrave A, Sredar N, Khushzad F, Yarp J, Tomczak A, Han M, Kipp L, Dubra A, Moss HE. Novel Foveal Features Associated With Vision Impairment in Multiple Sclerosis. Invest Ophthalmol Vis Sci 2021; 62:27. [PMID: 34581726 PMCID: PMC8479576 DOI: 10.1167/iovs.62.12.27] [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: 05/03/2021] [Accepted: 08/23/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose To characterize scattering and hyperreflective features in the foveal avascular zone of people with multiple sclerosis (MS) using adaptive optics scanning laser ophthalmoscopy (AOSLO) and to evaluate their relationship with visual function and MS disease characteristics. Methods Twenty subjects with MS underwent confocal reflectance and non-confocal split-detection AOSLO foveal imaging. Peripapillary retinal nerve fiber layer thickness was measured using optic nerve optical coherence tomography. Blood pressure, intraocular pressure (IOP), and best-corrected high-contrast visual acuity (HCVA) and low-contrast visual acuity (LCVA) were measured. AOSLO images were graded to determine the presence and characteristics of distinct structures. Results Two distinct structures were seen in the avascular zone of the foveal pit. Hyperreflective puncta, present in 74% of eyes, were associated with IOP and blood pressure. Scattering features, observed in 58% of eyes, were associated with decreased HCVA and LCVA, as well as increased MS duration and disability, but were not associated with retinal nerve fiber layer thickness. Hyperreflective puncta and scattering features were simultaneously present in 53% of eyes. Conclusions Hyperreflective puncta were associated with parameters affecting ophthalmic perfusion, but they were not associated with MS disease parameters. Scattering features were associated with parameters corresponding to advanced MS, suggesting that they may be related to disease progression. Scattering features were also correlated with reduced visual function independent from ganglion cell injury, suggesting the possibility of a novel ganglion cell-independent mechanism of impaired vision in people with MS.
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Affiliation(s)
- Aubrey Hargrave
- Department of Ophthalmology, Stanford University, Palo Alto, California, United States
| | - Nripun Sredar
- Department of Ophthalmology, Stanford University, Palo Alto, California, United States
| | - Fareshta Khushzad
- Department of Ophthalmology, Stanford University, Palo Alto, California, United States
| | - Jennifer Yarp
- Department of Ophthalmology, Stanford University, Palo Alto, California, United States
| | - Anna Tomczak
- Department of Neurology & Neurological Sciences, Stanford University, Palo Alto, California, United States
| | - May Han
- Department of Neurology & Neurological Sciences, Stanford University, Palo Alto, California, United States
| | - Lucas Kipp
- Department of Neurology & Neurological Sciences, Stanford University, Palo Alto, California, United States
| | - Alfredo Dubra
- Department of Ophthalmology, Stanford University, Palo Alto, California, United States
| | - Heather E. Moss
- Department of Ophthalmology, Stanford University, Palo Alto, California, United States
- Department of Neurology & Neurological Sciences, Stanford University, Palo Alto, California, United States
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12
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Gramlich OW, Godwin CR, Heuss ND, Gregerson DS, Kuehn MH. T and B Lymphocyte Deficiency in Rag1-/- Mice Reduces Retinal Ganglion Cell Loss in Experimental Glaucoma. Invest Ophthalmol Vis Sci 2021; 61:18. [PMID: 33320171 PMCID: PMC7745626 DOI: 10.1167/iovs.61.14.18] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Purpose We previously demonstrated that passive transfer of lymphocytes from glaucomatous mice induces retinal ganglion cell (RGC) damage in recipient animals, suggesting a role for immune responses in the multifactorial pathophysiology of glaucoma. Here we evaluate whether absence of an adaptive immune response reduces RGC loss in glaucoma. Methods Elevated intraocular pressure (IOP) was induced in one eye of C57BL/6J (B6) or T- and B-cell–deficient Rag1−/− knockout mice. After 16 weeks RGC density was determined in both the induced and the normotensive contralateral eyes. Data were compared to mice having received injections of “empty” vector (controls). The number of extravascular CD3+ cells in the retinas was determined using FACS. Results Retinas of eyes with elevated IOP contain significantly more extravasated CD3+ cells than control retinas (46.0 vs. 27.1, P = 0.025). After 16 weeks of elevated IOP the average RGC density in B6 mice decreased by 20.7% (P = 1.9 × 10−4). In contrast, RGC loss in Rag1−/− eyes with elevated IOP was significantly lower (10.3%, P = 0.006 vs. B6). RGC loss was also observed in the contralateral eyes of B6 mice, despite the absence of elevated IOP in those eyes (10.1%; P = 0.008). In RAG1−/− loss in the contralateral eyes was minimal (3.1%) and significantly below that detected in B6 (P = 0.02). Conclusions Our findings demonstrate that T Rag1−/− mice are significantly protected from glaucomatous RGC loss. In this model, lymphocyte activity contributes to approximately half of all RGC loss in eyes with elevated IOP and to essentially all loss observed in normotensive contralateral eyes.
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Affiliation(s)
- Oliver W Gramlich
- University of Iowa, Department of Ophthalmology and Visual Sciences, Iowa City, Iowa, United States.,Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, Iowa, United States
| | - Cheyanne R Godwin
- University of Iowa, Department of Ophthalmology and Visual Sciences, Iowa City, Iowa, United States.,Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, Iowa, United States
| | - Neal D Heuss
- University of Minnesota, Department of Ophthalmology and Visual Neurosciences, Minneapolis, Minnesota, United States
| | - Dale S Gregerson
- University of Minnesota, Department of Ophthalmology and Visual Neurosciences, Minneapolis, Minnesota, United States
| | - Markus H Kuehn
- University of Iowa, Department of Ophthalmology and Visual Sciences, Iowa City, Iowa, United States.,Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, Iowa, United States
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13
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The innate immune system in diabetic retinopathy. Prog Retin Eye Res 2021; 84:100940. [PMID: 33429059 DOI: 10.1016/j.preteyeres.2021.100940] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/24/2020] [Accepted: 01/03/2021] [Indexed: 12/20/2022]
Abstract
The prevalence of diabetes has been rising steadily in the past half-century, along with the burden of its associated complications, including diabetic retinopathy (DR). DR is currently the most common cause of vision loss in working-age adults in the United States. Historically, DR has been diagnosed and classified clinically based on what is visible by fundoscopy; that is vasculature alterations. However, recent technological advances have confirmed pathology of the neuroretina prior to any detectable vascular changes. These, coupled with molecular studies, and the positive impact of anti-inflammatory therapeutics in DR patients have highlighted the central involvement of the innate immune system. Reminiscent of the systemic impact of diabetes, immune dysregulation has become increasingly identified as a key element of the pathophysiology of DR by interfering with normal homeostatic systems. This review uses the growing body of literature across various model systems to demonstrate the clear involvement of all three pillars of the immune system: immune-competent cells, mediators, and the complement system. It also demonstrates how the relative contribution of each of these requires more extensive analysis, including in human tissues over the continuum of disease progression. Finally, although this review demonstrates how the complex interactions of the immune system pose many more questions than answers, the intimately connected nature of the three pillars of the immune system may also point to possible new targets to reverse or even halt reverse retinopathy.
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14
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Kutsyr O, Sánchez-Sáez X, Martínez-Gil N, de Juan E, Lax P, Maneu V, Cuenca N. Gradual Increase in Environmental Light Intensity Induces Oxidative Stress and Inflammation and Accelerates Retinal Neurodegeneration. Invest Ophthalmol Vis Sci 2021; 61:1. [PMID: 32744596 PMCID: PMC7441298 DOI: 10.1167/iovs.61.10.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Purpose Retinitis pigmentosa (RP) is a blinding neurodegenerative disease of the retina that can be affected by many factors. The present study aimed to analyze the effect of different environmental light intensities in rd10 mice retina. Methods C57BL/6J and rd10 mice were bred and housed under three different environmental light intensities: scotopic (5 lux), mesopic (50 lux), and photopic (300 lux). Visual function was studied using electroretinography and optomotor testing. The structural and morphological integrity of the retinas was evaluated by optical coherence tomography imaging and immunohistochemistry. Additionally, inflammatory processes and oxidative stress markers were analyzed by flow cytometry and western blotting. Results When the environmental light intensity was higher, retinal function decreased in rd10 mice and was accompanied by light-dependent photoreceptor loss, followed by morphological alterations, and synaptic connectivity loss. Moreover, light-dependent retinal degeneration was accompanied by an increased number of inflammatory cells, which became more activated and phagocytic, and by an exacerbated reactive gliosis. Furthermore, light-dependent increment in oxidative stress markers in rd10 mice retina pointed to a possible mechanism for light-induced photoreceptor degeneration. Conclusions An increase in rd10 mice housing light intensity accelerates retinal degeneration, activating cell death, oxidative stress pathways, and inflammatory cells. Lighting intensity is a key factor in the progression of retinal degeneration, and standardized lighting conditions are advisable for proper analysis and interpretation of experimental results from RP animal models, and specifically from rd10 mice. Also, it can be hypothesized that light protection could be an option to slow down retinal degeneration in some cases of RP.
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15
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Liu Y, Zhong H, Bussan EL, Pang IH. Early phosphoproteomic changes in the retina following optic nerve crush. Exp Neurol 2020; 334:113481. [PMID: 32971066 DOI: 10.1016/j.expneurol.2020.113481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/10/2020] [Accepted: 09/19/2020] [Indexed: 02/07/2023]
Abstract
Retinal ganglion cell (RGC) death causes irreversible blindness in adult mammals. Death of RGC occurs in diseases including glaucoma or injuries to the optic nerve (ON). To investigate mechanisms involved in RGC degeneration, we evaluated the phosphoproteomic changes in the retina induced by ON injury. Intraorbital optic nerve crush (ONC) was performed in adult C57BL/6J mice. Retinas were collected at 0, 6, and 12 h following ONC. Retinal proteins labeled with CyDye-C2 were subject to 2D-PAGE, followed by phosphoprotein staining and in-gel/cross-gel image analysis. Proteins with significant changes in phosphorylation (ratios ≥1.2) in retinas of the injured eyes compared to the control eyes were spot-picked, tryptic digested, and peptide fragments were analyzed by MALDI-TOF (MS) and TOF/TOF (tandem MS/MS). Intraorbital ONC increased phosphorylation of many retinal proteins. Among them, 29 significantly phosphorylated proteins were identified. PANTHER analysis showed that these proteins are associated with a variety of protein classes, cellular components, biological processes and signaling pathways. One of the identified proteins, phosphoprotein enriched in astrocytes 15 (PEA15), was further validated by western blotting and immunofluorescence staining. Functions of PEA15 were determined in cultured astrocytes. PEA15 knockdown reduced astrocyte phagocytic activity but promoted cell migration. Long term PEA15 knockdown also decreased astrocyte ATP level. This study provides new insights into mechanisms of RGC degeneration after ON injury, as well as central nervous system (CNS) neurodegeneration, since the retina is an extension of the CNS. These new insights will lead to novel therapeutic targets for retinal and CNS neurodegeneration.
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Affiliation(s)
- Yang Liu
- Department of Pharmacology & Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, USA.
| | - Huahong Zhong
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Ocular Trauma Treatment and Stem Cell Differentiation Public Service Platform of Shenzhen, Optometry College of Shenzhen University, Shenzhen, Guangdong, China
| | - Emily L Bussan
- Texas College of Osteopathic Medicine, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Iok-Hou Pang
- Department of Pharmaceutical Sciences, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, USA.
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16
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Jamali A, Kenyon B, Ortiz G, Abou-Slaybi A, Sendra VG, Harris DL, Hamrah P. Plasmacytoid dendritic cells in the eye. Prog Retin Eye Res 2020; 80:100877. [PMID: 32717378 DOI: 10.1016/j.preteyeres.2020.100877] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/28/2020] [Accepted: 06/05/2020] [Indexed: 02/07/2023]
Abstract
Plasmacytoid dendritic cells (pDCs) are a unique subpopulation of immune cells, distinct from classical dendritic cells. pDCs are generated in the bone marrow and following development, they typically home to secondary lymphoid tissues. While peripheral tissues are generally devoid of pDCs during steady state, few tissues, including the lung, kidney, vagina, and in particular ocular tissues harbor resident pDCs. pDCs were originally appreciated for their potential to produce large quantities of type I interferons in viral immunity. Subsequent studies have now unraveled their pivotal role in mediating immune responses, in particular in the induction of tolerance. In this review, we summarize our current knowledge on pDCs in ocular tissues in both mice and humans, in particular in the cornea, limbus, conjunctiva, choroid, retina, and lacrimal gland. Further, we will review our current understanding on the significance of pDCs in ameliorating inflammatory responses during herpes simplex virus keratitis, sterile inflammation, and corneal transplantation. Moreover, we describe their novel and pivotal neuroprotective role, their key function in preserving corneal angiogenic privilege, as well as their potential application as a cell-based therapy for ocular diseases.
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Affiliation(s)
- Arsia Jamali
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA; Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA
| | - Brendan Kenyon
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA; Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University, Boston, MA, USA
| | - Gustavo Ortiz
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA; Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA
| | - Abdo Abou-Slaybi
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA; Program in Immunology, Graduate School of Biomedical Sciences, Tufts University, Boston, MA, USA
| | - Victor G Sendra
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA; Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA
| | - Deshea L Harris
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA; Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA
| | - Pedram Hamrah
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA; Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA; Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University, Boston, MA, USA; Program in Immunology, Graduate School of Biomedical Sciences, Tufts University, Boston, MA, USA; Cornea Service, Tufts New England Eye Center, Boston, MA, USA.
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17
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Dudiki T, Meller J, Mahajan G, Liu H, Zhevlakova I, Stefl S, Witherow C, Podrez E, Kothapalli CR, Byzova TV. Microglia control vascular architecture via a TGFβ1 dependent paracrine mechanism linked to tissue mechanics. Nat Commun 2020; 11:986. [PMID: 32080187 PMCID: PMC7033106 DOI: 10.1038/s41467-020-14787-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 02/01/2020] [Indexed: 01/13/2023] Open
Abstract
Tissue microarchitecture and mechanics are important in development and pathologies of the Central Nervous System (CNS); however, their coordinating mechanisms are unclear. Here, we report that during colonization of the retina, microglia contacts the deep layer of high stiffness, which coincides with microglial bipolarization, reduction in TGFβ1 signaling and termination of vascular growth. Likewise, stiff substrates induce microglial bipolarization and diminish TGFβ1 expression in hydrogels. Both microglial bipolarization in vivo and the responses to stiff substrates in vitro require intracellular adaptor Kindlin3 but not microglial integrins. Lack of Kindlin3 causes high microglial contractility, dysregulation of ERK signaling, excessive TGFβ1 expression and abnormally-patterned vasculature with severe malformations in the area of photoreceptors. Both excessive TGFβ1 signaling and vascular defects caused by Kindlin3-deficient microglia are rescued by either microglial depletion or microglial knockout of TGFβ1 in vivo. This mechanism underlies an interplay between microglia, vascular patterning and tissue mechanics within the CNS.
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Affiliation(s)
- Tejasvi Dudiki
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Julia Meller
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Gautam Mahajan
- Chemical and Biomedical Engineering Department, Washkewicz College of Engineering, Cleveland State University, Cleveland, OH, USA
| | - Huan Liu
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Irina Zhevlakova
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Samantha Stefl
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.,Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Conner Witherow
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.,Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Eugene Podrez
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Chandrasekhar R Kothapalli
- Chemical and Biomedical Engineering Department, Washkewicz College of Engineering, Cleveland State University, Cleveland, OH, USA
| | - Tatiana V Byzova
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.
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18
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McPherson SW, Heuss ND, Lehmann U, Roehrich H, Abedin M, Gregerson DS. The retinal environment induces microglia-like properties in recruited myeloid cells. J Neuroinflammation 2019; 16:151. [PMID: 31325968 PMCID: PMC6642741 DOI: 10.1186/s12974-019-1546-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 07/11/2019] [Indexed: 12/31/2022] Open
Abstract
Background Microglia are essential to the development of the CNS and its homeostasis. Our prior findings suggested a niche model to describe the behaviors of retinal microglia. Here, we ask whether new myeloid cells recruited to the retina are constrained to resemble endogenous microglia morphologically and functionally. Methods Use of CD11cDTR/GFP transgenic mouse allowed identification of two niches of retinal microglia distinguished by being GFPlo or GFPhi. We also used transgenic mice in which CX3CR1+ cells expressed YFP and were depletable following tamoxifen-induced expression of diphtheria toxin subunit A. We employed several ablation and injury stimulation protocols to examine the origin and fate of myeloid cells repopulating the retina. Analysis of retinal myeloid cells was done by microscopy, flow cytometry, and qRT-PCR. Results We found that the origin of new GFPhi and GFPlo myeloid cells in the retina of CD11cDTR/GFP mice, whether recruited or local, depended on the ablation and stimulation protocols. Regardless of origin, new GFPlo and GFPhi retinal myeloid cells were CD45medCD11b+Ly6G−Ly6CloIba1+F4/80+, similar to endogenous microglia. Following tamoxifen-induced diphtheria toxin ablation, myeloid cell repopulation differed in the retina compared to the brain and optic nerve. Stimulation of replacement GFPhi cells was substantially attenuated in repopulating retinas after tamoxifen-induced diphtheria toxin ablation compared to control or radiation-ablated mice. In radiation bone marrow chimeric mice, replacement GFPhi myeloid cells from the circulation were slow to repopulate the retina unless stimulated by an optic nerve crush injury. However, once stimulated, recruited GFPhi cells were found to concentrate on injured retinal ganglion cells and were morphologically similar to GFPhi cells in non-ablated control CD11cDTR/GFP mice. Conclusions The results support the idea that GFPhi cells in the CD11cDTR/GFP mouse, whether recruited or from resident microglia, mark a unique niche of activated retinal myeloid cells. We conclude that the retinal environment has a potent influence on the function, morphology, and proliferative capacity of new myeloid cells regardless of their origin, compelling them to be equivalent to the endogenous microglia. Electronic supplementary material The online version of this article (10.1186/s12974-019-1546-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Scott W McPherson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, 2001 6th Street SE, LRB Room 314, Minneapolis, MN, 55455, USA.
| | - Neal D Heuss
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, 2001 6th Street SE, LRB Room 314, Minneapolis, MN, 55455, USA
| | - Ute Lehmann
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, 2001 6th Street SE, LRB Room 314, Minneapolis, MN, 55455, USA
| | - Heidi Roehrich
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, 2001 6th Street SE, LRB Room 314, Minneapolis, MN, 55455, USA
| | - Md Abedin
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, 2001 6th Street SE, LRB Room 314, Minneapolis, MN, 55455, USA
| | - Dale S Gregerson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, 2001 6th Street SE, LRB Room 314, Minneapolis, MN, 55455, USA
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19
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Bariş M, Tezel G. Immunomodulation as a Neuroprotective Strategy for Glaucoma Treatment. CURRENT OPHTHALMOLOGY REPORTS 2019; 7:160-169. [PMID: 31360618 PMCID: PMC6662642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
PURPOSE OF REVIEW This review aims to highlight the current knowledge about inflammatory mechanisms of neurodegeneration in glaucoma with emphasis on potential immunomodulation strategies. RECENT FINDINGS Glaucomatous retina and optic nerve present multiple evidences of inflammatory responses of astroglia, microglia, and blood-born immune cells. Although adaptive/protective responses of resident or systemic immune cells can support neurons and promote tissue repair mechanisms after injurious insults, prolonged inflammatory processes can also produce neurotoxic mediators. Treatments targeting these neurodestructive outcomes may restore immune homeostasis and protect neurons from inflammatory injury. Due to widespread and chronic nature of neuroinflammation in glaucoma, immunomodulation offers a treatment strategy to protect different neuronal compartments of RGCs during the chronic and asynchronous course of neurodegeneration. Uncovering of distinct molecular responses and interactions of different immune cells that determine the neuroinflammatory phenotype and participate in neurodegenerative outcomes will be critical to develop effective strategies for immunomodulation in glaucoma. SUMMARY Neuroinflammation has increasingly been recognized to play an important role in glaucomatous neurodegeneration, and its modulation appears to be a promising treatment strategy for neuroprotection.
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Affiliation(s)
- Mine Bariş
- Columbia University, College of Physicians and Surgeons, Department of Ophthalmology, New York, NY
| | - Gülgün Tezel
- Columbia University, College of Physicians and Surgeons, Department of Ophthalmology, New York, NY
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20
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21
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Karlen SJ, Miller EB, Wang X, Levine ES, Zawadzki RJ, Burns ME. Monocyte infiltration rather than microglia proliferation dominates the early immune response to rapid photoreceptor degeneration. J Neuroinflammation 2018; 15:344. [PMID: 30553275 PMCID: PMC7659426 DOI: 10.1186/s12974-018-1365-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 11/11/2018] [Indexed: 01/07/2023] Open
Abstract
Background Activation of resident microglia accompanies every known form of neurodegeneration, but the involvement of peripheral monocytes that extravasate and rapidly transform into microglia-like macrophages within the central nervous system during degeneration is far less clear. Methods Using a combination of in vivo ocular imaging, flow cytometry, and immunohistochemistry, we investigated the response of infiltrating cells in a light-inducible mouse model of photoreceptor degeneration. Results Within 24 h, resident microglia became activated and began migrating to the site of degeneration. Retinal expression of CCL2 increased just prior to a transient period of CCR2+ cell extravasation from the retinal vasculature. Proliferation of microglia and monocytes occurred concurrently; however, there was no indication of proliferation in either population until 72–96 h after neurodegeneration began. Eliminating CCL2-CCR2 signaling blocked monocyte recruitment, but did not alter the extent of retinal degeneration. Conclusions These results demonstrate that the immune response to photoreceptor degeneration includes both resident microglia and monocytes, even at very early times. Surprisingly, preventing monocyte infiltration did not block neurodegeneration, suggesting that in this model, degeneration is limited by cell clearance from other phagocytes or by the timing of intrinsic cell death programs. These results show monocyte involvement is not limited to disease states that overwhelm or deplete the resident microglial population and that interventions focused on modulating the peripheral immune system are not universally beneficial for staving off degeneration. Electronic supplementary material The online version of this article (10.1186/s12974-018-1365-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sarah J Karlen
- Department of Cell Biology and Human Anatomy, University of California, Davis, 1 Shields Avenue, Davis, CA, 95616, USA
| | - Eric B Miller
- Center for Neuroscience, University of California, Davis, 1544 Newton Court, Davis, CA, 95618, USA
| | - Xinlei Wang
- Department of Cell Biology and Human Anatomy, University of California, Davis, 1 Shields Avenue, Davis, CA, 95616, USA.,Department of Ophthalmology & Vision Science, University of California, Davis, 1 Shields Avenue, Davis, CA, 95616, USA
| | - Emily S Levine
- Department of Cell Biology and Human Anatomy, University of California, Davis, 1 Shields Avenue, Davis, CA, 95616, USA
| | - Robert J Zawadzki
- Department of Ophthalmology & Vision Science, University of California, Davis, 1 Shields Avenue, Davis, CA, 95616, USA
| | - Marie E Burns
- Department of Cell Biology and Human Anatomy, University of California, Davis, 1 Shields Avenue, Davis, CA, 95616, USA. .,Center for Neuroscience, University of California, Davis, 1544 Newton Court, Davis, CA, 95618, USA. .,Department of Ophthalmology & Vision Science, University of California, Davis, 1 Shields Avenue, Davis, CA, 95616, USA.
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22
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McMenamin PG, Saban DR, Dando SJ. Immune cells in the retina and choroid: Two different tissue environments that require different defenses and surveillance. Prog Retin Eye Res 2018; 70:85-98. [PMID: 30552975 DOI: 10.1016/j.preteyeres.2018.12.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 12/03/2018] [Accepted: 12/11/2018] [Indexed: 01/04/2023]
Abstract
In the eye immune defenses must take place in a plethora of differing microenvironments ranging from the corneal and conjunctival epithelia facing the external environment to the pigmented connective tissue of the uveal tract containing smooth muscle, blood vessels and peripheral nerves to the innermost and highly protected neural retina. The extravascular environment of the neural retina, like the brain parenchyma, is stringently controlled to maintain conditions required for neural transmission. The unique physiological nature of the neural retina can be attributed to the blood retinal barriers (BRB) of the retinal vasculature and the retinal pigment epithelium, which both tightly regulate the transport of small molecules and restrict passage of cells and macromolecules from the circulation into the retina in a similar fashion to the blood brain barrier (BBB). The extracellular environment of the neural retina differs markedly from that of the highly vascular, loose connective tissue of the choroid, which lies outside the BRB. The choroid hosts a variety of immune cell types, including macrophages, dendritic cells (DCs) and mast cells. This is in marked contrast to the neural parenchyma of the retina, which is populated almost solely by microglia. This review will describe the current understanding of the distribution, phenotype and physiological role of ocular immune cells behind or inside the blood-retinal barriers and those in closely juxtaposed tissues outside the barrier. The nature and function of these immune cells can profoundly influence retinal homeostasis and lead to disordered immune function that can lead to vision loss.
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Affiliation(s)
- Paul G McMenamin
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
| | - Daniel R Saban
- Department of Ophthalmology, Department of Immunology, Duke University School of Medicine, Durham, NC, USA
| | - Samantha J Dando
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
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23
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Bell K, Und Hohenstein-Blaul NVT, Teister J, Grus F. Modulation of the Immune System for the Treatment of Glaucoma. Curr Neuropharmacol 2018; 16:942-958. [PMID: 28730968 PMCID: PMC6120111 DOI: 10.2174/1570159x15666170720094529] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/17/2017] [Accepted: 07/18/2017] [Indexed: 12/20/2022] Open
Abstract
Background: At present intraocular pressure (IOP) lowering therapies are the only approach to treat glaucoma. Neuroprotective strategies to protect the retinal ganglion cells (RGC) from apoptosis are lacking to date. Substantial amount of research concerning the role of the immune system in glaucoma has been performed in the recent years. This review aims to analyse changes found in the peripheral immune system, as well as selected local changes of retina immune cells in the glaucomatous retina. Methods: By dividing the immune system into the innate and the adaptive immune system, a systematic literature research was performed to find recent approaches concerning the modulation of the immune system in the context of glaucoma. Also ClinicalTrials.gov was assessed to identify studies with a translational context. Results: We found that some aspects of the immune system, such as changes in antibody levels, changes in toll like receptor signalling, T cells and retinal microglial cells, experience more research activity than other areas such as changes in dendritic cells or macrophages. Briefly, results from clinical studies revealed altered immunoreactivities against retinal and optic nerve antigens in sera and aqueous humor of glaucoma patients and point toward an autoimmune involvement in glaucomatous neurodegeneration and RGC death. IgG accumulations along with plasma cells were found localised in human glaucomatous retinae in a pro-inflammatory environment possibly maintained by microglia. Animal studies show that antibodies (e.g. anti- heat shock protein 60 and anti-myelin basic protein) elevated in glaucoma patients provoke autoaggressive RGC loss and are associated with IgG depositions and increased microglial cells. Also, studies addressing changes in T lymphocytes, macrophages but also local immune responses in the retina have been performed and also hold promising results. Conclusions: This recapitulation of recent literature demonstrates that the immune system definitely plays a role in the pathogenesis of glaucoma. Multiple changes in the peripheral innate as well as adaptive immune system have been detected and give room for further research concerning valuable therapeutic targets. We conclude that there still is a great need to bring together the results derived from basic research analysing different aspects of the immune system in glaucoma to understand the immune context of the disease. Furthermore local immune changes in the retina of glaucoma patients still leave room for further therapeutic targets
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Affiliation(s)
- Katharina Bell
- Experimental and Translational Ophthalmology Mainz, Department of Ophthalmology, Medical Center of the Johannes Gutenberg University Mainz; Langenbeckstrasse 1, 55101 Mainz, Germany
| | - Nadine von Thun Und Hohenstein-Blaul
- Experimental and Translational Ophthalmology Mainz, Department of Ophthalmology, Medical Center of the Johannes Gutenberg University Mainz; Langenbeckstrasse 1, 55101 Mainz, Germany
| | - Julia Teister
- Experimental and Translational Ophthalmology Mainz, Department of Ophthalmology, Medical Center of the Johannes Gutenberg University Mainz; Langenbeckstrasse 1, 55101 Mainz, Germany
| | - Franz Grus
- Experimental and Translational Ophthalmology Mainz, Department of Ophthalmology, Medical Center of the Johannes Gutenberg University Mainz; Langenbeckstrasse 1, 55101 Mainz, Germany
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Heuss ND, Pierson MJ, Roehrich H, McPherson SW, Gram AL, Li L, Gregerson DS. Optic nerve as a source of activated retinal microglia post-injury. Acta Neuropathol Commun 2018; 6:66. [PMID: 30037353 PMCID: PMC6055350 DOI: 10.1186/s40478-018-0571-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 07/15/2018] [Indexed: 12/27/2022] Open
Abstract
Using mice expressing green fluorescent protein (GFP) from a transgenic CD11c promoter we found that a controlled optic nerve crush (ONC) injury attracted GFPhi retinal myeloid cells to the dying retinal ganglion cells and their axons. However, the origin of these retinal myeloid cells was uncertain. In this study we use transgenic mice in conjunction with ONC, partial and full optic nerve transection (ONT), and parabiosis to determine the origin of injury induced retinal myeloid cells. Analysis of parabiotic mice and fate mapping showed that responding retinal myeloid cells were not derived from circulating macrophages and that GFPhi myeloid cells could be derived from GFPlo microglia. Comparison of optic nerve to retina following an ONC showed a much greater concentration of GFPhi cells and GFPlo microglia in the optic nerve. Optic nerve injury also induced Ki67+ cells in the optic nerve but not in the retina. Comparison of the retinal myeloid cell response after full versus partial ONT revealed fewer GFPhi cells and GFPlo microglia in the retina following a full ONT despite it being a more severe injury, suggesting that full transection of the optic nerve can block the migration of responding myeloid cells to the retina. Our results suggest that the optic nerve can be a reservoir for activated microglia and other retinal myeloid cells in the retina following optic nerve injury.
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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: 127] [Impact Index Per Article: 21.2] [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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Saban DR. New concepts in macrophage ontogeny in the adult neural retina. Cell Immunol 2018; 330:79-85. [PMID: 29703455 DOI: 10.1016/j.cellimm.2018.04.008] [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: 11/02/2017] [Revised: 04/20/2018] [Accepted: 04/20/2018] [Indexed: 12/16/2022]
Abstract
The number of neurons dedicated to vision itself is thought to be greater than the sum of the four other senses combined. Yet, little attention has been payed to the retina as compared to elsewhere in the central nervous system with respect to microglia, the macrophages of the neural parenchyma. Indeed, major advancements in the understanding of microglial ontogeny and maintenance in brain and spinal cord are now widely appreciated, whereas less notice has been given to the neural retina in this regard. The current Review covers topical concepts on adult microglia and perivascular macrophage ontogenies in the steady state retina, as well as parallels made with these macrophages in other areas of the central nervous system. The subject of recruited monocytes and their descendant monocyte-derived macrophages in degenerative diseases of the retina is also integrated into this Review. Key experiments that have led to the theories covered are highlighted throughout, as are the knowledge gaps that remain unresolved.
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Affiliation(s)
- Daniel R Saban
- Duke University School of Medicine, Department of Ophthalmology, Durham, NC, USA; Duke University School of Medicine, Department of Immunology, Durham, NC, USA.
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Tang PH, Pierson MJ, Heuss ND, Gregerson DS. A subpopulation of activated retinal macrophages selectively migrated to regions of cone photoreceptor stress, but had limited effect on cone death in a mouse model for type 2 Leber congenital amaurosis. Mol Cell Neurosci 2017; 85:70-81. [PMID: 28889993 DOI: 10.1016/j.mcn.2017.09.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 08/15/2017] [Accepted: 09/06/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Studies of antigen presentation in retina using mice that expressed green fluorescent protein (GFP) from a transgenic CD11c promoter found that retinal GFPhi cells possessed antigen presentation function. Subsequent studies found that these high GFPhi cells preferentially localized to sites of retinal injury, consistent with their APC function. Interest in the roles of macrophages in degenerative CNS diseases led us to study the GFPhi cells in a retinal model of neurodegeneration. We asked if apoptotic cone photoreceptor cell death in Rpe65-/- knockout mice induced the GFPhi cells, explored their relationship to resident microglia (MG), and tested their role in cone survival. METHODS Rpe65-/- mice were bred to CD11cGFP mice on the B6/J background. CD11cGFPRpe65-/- mice were also backcrossed to CX3CR1YFP-creERROSADTA mice so that CX3CR1+ mononuclear cells could be depleted by Tamoxifen. Retinas were analyzed by immunohistochemistry, confocal microscopy, fluorescence fundoscopy and flow cytometry. RESULTS Elevated numbers of GFPhi cells were concentrated in photoreceptor cell layers of CD11cGFPRpe65-/- mice coinciding with the peak of cone death at 2 to 4weeks of age, and persisted for at least 14months. After the initial wave of cone loss, a slow progressive loss of cones was found that continued to retain GFPhi cells in the outer retina. Sustained, four-week Tamoxifen depletions of the GFPhi cells and MG in Rpe65-/- mice from day 13 to day 41, and from day 390 to day 420 promoted a small increase in cone survival. We found no evidence that the GFPhi cells were recruited from the circulation; all data pointed to a MG origin. MG and GFPhi cells were well segregated in the dystrophic retina; GFPhi cells were foremost in the photoreceptor cell layer, while MG were concentrated in the inner retina. CONCLUSIONS The expression of GFP on a subset of retinal mononuclear cells in CD11cGFP mice identified a distinct population of cells performing functions previously attributed to MG. Although GFPhi cells dominated the macrophage response to cone death in the photoreceptor cell layer, their ablation led to only an incremental increase in cone survival. The ability to identify, ablate, and isolate these cells will facilitate analysis of this activated, antigen-presenting subset of MG.
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Affiliation(s)
- Peter H Tang
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, United States
| | - Mark J Pierson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, United States
| | - Neal D Heuss
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, United States
| | - Dale S Gregerson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, United States.
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Umazume A, Kezuka T, Matsuda R, Usui Y, Takahashi H, Yamakawa N, Yashiro T, Nishiyama C, Goto H. Role of PU.1 Expression as an Inflammatory Marker in Experimental Autoimmune Uveoretinitis. Ocul Immunol Inflamm 2017; 26:951-963. [PMID: 28448751 DOI: 10.1080/09273948.2017.1299867] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE PU.1 is an Ets family transcription factor, which is essential for the development of immune system through generation of myeloid and lymphoid lineages. In this study, we investigated PU.1 expression in the retina of mice with experimental autoimmune uveoretinitis (EAU) and the association between PU.1 expression level and inflammation in EAU. METHODS IRBP 1-20 peptide-immunized mice were used. Quantitative PCR, ELISA analysis, cytometric bead array (CBA), assay and immunostaining were conducted using ocular tissues and lymph nodes. RESULTS Quantitative PCR showed significant increases in mRNA levels of PU.1 in the retina at the peak of inflammation. Immunostaining of retina flat mounts revealed that most PU.1-positive cells were co-stained with anti-CD11c and anti-F4/80 antibodies. PU.1 knockdown in lymph node cells significantly suppressed IRBP-stimulated IFN-γ production measured by ELISA and IL-2 production measured by CBA. CONCLUSION PU.1 may play crucial roles in the development and progression of inflammation in EAU.
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Affiliation(s)
- Akihiko Umazume
- a Department of Ophthalmology , Tokyo Medical University , Shinjuku-ku , Tokyo , Japan.,b Department of Biological Science and Technology , Faculty of Industrial Science and Technology, Tokyo University of Science , Katsushika-ku , Tokyo , Japan
| | - Takeshi Kezuka
- a Department of Ophthalmology , Tokyo Medical University , Shinjuku-ku , Tokyo , Japan
| | - Ryusaku Matsuda
- a Department of Ophthalmology , Tokyo Medical University , Shinjuku-ku , Tokyo , Japan
| | - Yoshihiko Usui
- a Department of Ophthalmology , Tokyo Medical University , Shinjuku-ku , Tokyo , Japan
| | - Hiroki Takahashi
- a Department of Ophthalmology , Tokyo Medical University , Shinjuku-ku , Tokyo , Japan
| | - Naoyuki Yamakawa
- a Department of Ophthalmology , Tokyo Medical University , Shinjuku-ku , Tokyo , Japan
| | - Takuya Yashiro
- b Department of Biological Science and Technology , Faculty of Industrial Science and Technology, Tokyo University of Science , Katsushika-ku , Tokyo , Japan
| | - Chiharu Nishiyama
- b Department of Biological Science and Technology , Faculty of Industrial Science and Technology, Tokyo University of Science , Katsushika-ku , Tokyo , Japan
| | - Hiroshi Goto
- a Department of Ophthalmology , Tokyo Medical University , Shinjuku-ku , Tokyo , Japan
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Manthey AL, Chiu K, So KF. Effects of Lycium barbarum on the Visual System. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2017; 135:1-27. [PMID: 28807155 DOI: 10.1016/bs.irn.2017.02.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Lycium barbarum (wolfberry, gogi berry, gouqizi, ) is one of the most widely used Chinese herbal medicines (CHMs) and is also one of the most scientifically studied. Indeed, the polysaccharide component of this berry (LBP) has been shown to have antioxidant, antiinflammatory, antiexcitotoxic, and antiapoptotic properties. These properties make it a particularly useful treatment option for the ocular environment. Although there are a handful of studies investigating the use of LBP to treat diseases affecting the lens, the vast majority of the published literature investigating LBP in the visual system focus on the retina. In this chapter, we have described what is currently understood concerning the effects of LBP treatment on various retinal diseases, including glaucoma, ischemia/reperfusion, age-related macular degeneration, retinitis pigmentosa, and diabetic retinopathy. We then describe the functions attributed to LBP using other cellular contexts to elucidate the full mechanisms this CHM utilizes in the retina. By making connections between what is known about the function of LBP in a variety of tissues and its function as a therapy for retinal degenerative diseases, we hope to further emphasize the continued use of this CHM in clinical medicine in addition to providing a platform for additional study.
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Affiliation(s)
| | - Kin Chiu
- The University of Hong Kong, Hong Kong SAR, China; State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, SAR, China.
| | - Kwok-Fai So
- The University of Hong Kong, Hong Kong SAR, China; State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, SAR, China; Guangdong-Hong Kong-Macau Institute of CNS Regeneration and Guangdong Key Laboratory of Brain Function and Diseases, Jinan University, Guangzhou, China; Ministry of Education Joint International Research Laboratory of CNS Regeneration, Jinan University, Guangzhou, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China.
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Maes ME, Schlamp CL, Nickells RW. BAX to basics: How the BCL2 gene family controls the death of retinal ganglion cells. Prog Retin Eye Res 2017; 57:1-25. [PMID: 28064040 DOI: 10.1016/j.preteyeres.2017.01.002] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/22/2016] [Accepted: 01/03/2017] [Indexed: 12/19/2022]
Abstract
Retinal ganglion cell (RGC) death is the principal consequence of injury to the optic nerve. For several decades, we have understood that the RGC death process was executed by apoptosis, suggesting that there may be ways to therapeutically intervene in this cell death program and provide a more direct treatment to the cells and tissues affected in diseases like glaucoma. A major part of this endeavor has been to elucidate the molecular biological pathways active in RGCs from the point of axonal injury to the point of irreversible cell death. A major component of this process is the complex interaction of members of the BCL2 gene family. Three distinct family members of proteins orchestrate the most critical junction in the apoptotic program of RGCs, culminating in the activation of pro-apoptotic BAX. Once active, BAX causes irreparable damage to mitochondria, while precipitating downstream events that finish off a dying ganglion cell. This review is divided into two major parts. First, we summarize the extent of knowledge of how BCL2 gene family proteins interact to facilitate the activation and function of BAX. This area of investigation has rapidly changed over the last few years and has yielded a dramatically different mechanistic understanding of how the intrinsic apoptotic program is run in mammalian cells. Second, we provided a comprehensive analysis of nearly two decades of investigation of the role of BAX in the process of RGC death, much of which has provided many important insights into the overall pathophysiology of diseases like glaucoma.
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Affiliation(s)
- Margaret E Maes
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Cassandra L Schlamp
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Robert W Nickells
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA.
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Breen KT, Anderson SR, Steele MR, Calkins DJ, Bosco A, Vetter ML. Loss of Fractalkine Signaling Exacerbates Axon Transport Dysfunction in a Chronic Model of Glaucoma. Front Neurosci 2016; 10:526. [PMID: 27932942 PMCID: PMC5123443 DOI: 10.3389/fnins.2016.00526] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 10/31/2016] [Indexed: 01/01/2023] Open
Abstract
Neurodegeneration in glaucoma results in decline and loss of retinal ganglion cells (RGCs), and is associated with activation of myeloid cells such as microglia and macrophages. The chemokine fractalkine (FKN or Cx3cl1) mediates communication from neurons to myeloid cells. Signaling through its receptor Cx3cr1 has been implicated in multiple neurodegenerative diseases, but the effects on neuronal pathology are variable. Since it is unknown how FKN-mediated crosstalk influences RGC degeneration in glaucoma, we assessed this in a chronic mouse model, DBA/2J. We analyzed a DBA/2J substrain deficient in Cx3cr1, and compared compartmentalized RGC degeneration and myeloid cell responses to those in standard DBA/2J mice. We found that loss of FKN signaling exacerbates axon transport dysfunction, an early event in neurodegeneration, with a significant increase in RGCs with somal accumulation of the axonal protein phosphorylated neurofilament, and reduced retinal expression of genes involved in axon transport, Kif1b, and Atp8a2. There was no change in the loss of Brn3-positive RGCs, and no difference in the extent of damage to the proximal optic nerve, suggesting that the loss of fractalkine signaling primarily affects axon transport. Since Cx3cr1 is specifically expressed in myeloid cells, we assessed changes in retinal microglial number and activation, changes in gene expression, and the extent of macrophage infiltration. We found that loss of fractalkine signaling led to innate immune changes within the retina, including increased infiltration of peripheral macrophages and upregulated nitric oxide synthase-2 (Nos-2) expression in myeloid cells, which contributes to the production of NO and can promote axon transport deficits. In contrast, resident retinal microglia appeared unchanged either in number, morphology, or expression of the myeloid activation marker ionized calcium binding adaptor molecule 1 (Iba1). There was also no significant increase in the proinflammatory gene interleukin 1 beta (Il1β). We conclude that loss of fractalkine signaling causes a selective worsening of axon transport dysfunction in RGCs, which is linked to enhanced Nos-2 expression in myeloid cells. Our findings suggest that distinct mechanisms may contribute to different aspects of RGC decline in glaucoma, with axonal transport selectively altered after loss of Cx3cr1 in microglia and/or macrophages.
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Affiliation(s)
- Kevin T Breen
- Departments of Neurobiology and Anatomy, University of Utah Salt Lake City, UT, USA
| | - Sarah R Anderson
- Departments of Neurobiology and Anatomy, University of Utah Salt Lake City, UT, USA
| | - Michael R Steele
- Departments of Neurobiology and Anatomy, University of Utah Salt Lake City, UT, USA
| | - David J Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Nashville, TN, USA
| | - Alejandra Bosco
- Departments of Neurobiology and Anatomy, University of Utah Salt Lake City, UT, USA
| | - Monica L Vetter
- Departments of Neurobiology and Anatomy, University of Utah Salt Lake City, UT, USA
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Proekt I, Miller CN, Jeanne M, Fasano KJ, Moon JJ, Lowell CA, Gould DB, Anderson MS, DeFranco AL. LYN- and AIRE-mediated tolerance checkpoint defects synergize to trigger organ-specific autoimmunity. J Clin Invest 2016; 126:3758-3771. [PMID: 27571405 PMCID: PMC5087700 DOI: 10.1172/jci84440] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 07/22/2016] [Indexed: 01/07/2023] Open
Abstract
Studies of the genetic factors associated with human autoimmune disease suggest a multigenic origin of susceptibility; however, how these factors interact and through which tolerance pathways they operate generally remain to be defined. One key checkpoint occurs through the activity of the autoimmune regulator AIRE, which promotes central T cell tolerance. Recent reports have described a variety of dominant-negative AIRE mutations that likely contribute to human autoimmunity to a greater extent than previously thought. In families with these mutations, the penetrance of autoimmunity is incomplete, suggesting that other checkpoints play a role in preventing autoimmunity. Here, we tested whether a defect in LYN, an inhibitory protein tyrosine kinase that is implicated in systemic autoimmunity, could combine with an Aire mutation to provoke organ-specific autoimmunity. Indeed, mice with a dominant-negative allele of Aire and deficiency in LYN spontaneously developed organ-specific autoimmunity in the eye. We further determined that a small pool of retinal protein-specific T cells escaped thymic deletion as a result of the hypomorphic Aire function and that these cells also escaped peripheral tolerance in the presence of LYN-deficient dendritic cells, leading to highly destructive autoimmune attack. These findings demonstrate how 2 distinct tolerance pathways can synergize to unleash autoimmunity and have implications for the genetic susceptibility of autoimmune disease.
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Affiliation(s)
| | | | - Marion Jeanne
- Departments of Ophthalmology and Anatomy, Institute for Human Genetics, UCSF, San Francisco, California, USA
| | | | - James J. Moon
- Center for Immunology and Inflammatory Diseases and Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | | | - Douglas B. Gould
- Departments of Ophthalmology and Anatomy, Institute for Human Genetics, UCSF, San Francisco, California, USA
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Xu H, Chen M. Targeting the complement system for the management of retinal inflammatory and degenerative diseases. Eur J Pharmacol 2016; 787:94-104. [PMID: 26948311 PMCID: PMC5026403 DOI: 10.1016/j.ejphar.2016.03.001] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 01/12/2016] [Accepted: 03/01/2016] [Indexed: 12/20/2022]
Abstract
The retina, an immune privileged tissue, has specialized immune defense mechanisms against noxious insults that may exist in diseases such as age-related macular degeneration (AMD), diabetic retinopathy (DR), uveoretinitis and glaucoma. The defense system consists of retinal innate immune cells (including microglia, perivascular macrophages, and a small population of dendritic cells) and the complement system. Under normal aging conditions, retinal innate immune cells and the complement system undergo a low-grade activation (parainflammation) which is important for retinal homeostasis. In disease states such as AMD and DR, the parainflammatory response is dysregulated and develops into detrimental chronic inflammation. Complement activation in the retina is an important part of chronic inflammation and may contribute to retinal pathology in these disease states. Here, we review the evidence that supports the role of uncontrolled or dysregulated complement activation in various retinal degenerative and angiogenic conditions. We also discuss current strategies that are used to develop complement-based therapies for retinal diseases such as AMD. The potential benefits of complement inhibition in DR, uveoretinitis and glaucoma are also discussed, as well as the need for further research to better understand the mechanisms of complement-mediated retinal damage in these disease states.
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Affiliation(s)
- Heping Xu
- Centre for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, UK.
| | - Mei Chen
- Centre for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, UK.
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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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Dando SJ, Naranjo Golborne C, Chinnery HR, Ruitenberg MJ, McMenamin PG. A case of mistaken identity: CD11c-eYFP(+) cells in the normal mouse brain parenchyma and neural retina display the phenotype of microglia, not dendritic cells. Glia 2016; 64:1331-49. [PMID: 27189804 DOI: 10.1002/glia.23005] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 04/25/2016] [Accepted: 04/25/2016] [Indexed: 12/13/2022]
Abstract
Under steady-state conditions the central nervous system (CNS) is traditionally thought to be devoid of antigen presenting cells; however, putative dendritic cells (DCs) expressing enhanced yellow fluorescent protein (eYFP) are present in the retina and brain parenchyma of CD11c-eYFP mice. We previously showed that these mice carry the Crb1(rd8) mutation, which causes retinal dystrophic lesions; therefore we hypothesized that the presence of CD11c-eYFP(+) cells within the CNS may be due to pathology associated with the Crb1(rd8) mutation. We generated CD11c-eYFP Crb1(wt/wt) mice and compared the distribution and immunophenotype of CD11c-eYFP(+) cells in CD11c-eYFP mice with and without the Crb1(rd8) mutation. The number and distribution of CD11c-eYFP(+) cells in the CNS was similar between CD11c-eYFP Crb1(wt/wt) and CD11c-eYFP Crb1(rd8/rd8) mice. CD11c-eYFP(+) cells were distributed throughout the inner retina, and clustered in brain regions that receive input from the external environment or lack a blood-brain barrier. CD11c-eYFP(+) cells within the retina and cerebral cortex of CD11c-eYFP Crb1(wt/wt) mice expressed CD11b, F4/80, CD115 and Iba-1, but not DC or antigen presentation markers, whereas CD11c-eYFP(+) cells within the choroid plexus and pia mater expressed CD11c, I-A/I-E, CD80, CD86, CD103, DEC205, CD8α and CD135. The immunophenotype of CD11c-eYFP(+) cells and microglia within the CNS was similar between CD11c-eYFP Crb1(wt/wt) and CD11c-eYFP Crb1(rd8/rd8) mice; however, CD11c and I-A/I-E expression was significantly increased in CD11c-eYFP Crb1(rd8/rd8) mice. This study demonstrates that the overwhelming majority of CNS CD11c-eYFP(+) cells do not display the phenotype of DCs or their precursors and are most likely a subpopulation of microglia. GLIA 2016. GLIA 2016;64:1331-1349.
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Affiliation(s)
- Samantha J Dando
- Department of Anatomy and Developmental Biology and Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Cecilia Naranjo Golborne
- Department of Anatomy and Developmental Biology and Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Holly R Chinnery
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Marc J Ruitenberg
- School of Biomedical Sciences, the University of Queensland, Brisbane, Queensland, Australia.,Queensland Brain Institute, the University of Queensland, Brisbane, Queensland, Australia
| | - Paul G McMenamin
- Department of Anatomy and Developmental Biology and Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
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Fate mapping reveals that microglia and recruited monocyte-derived macrophages are definitively distinguishable by phenotype in the retina. Sci Rep 2016; 6:20636. [PMID: 26856416 PMCID: PMC4746646 DOI: 10.1038/srep20636] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 01/06/2016] [Indexed: 12/14/2022] Open
Abstract
The recent paradigm shift that microglia are yolk sac-derived, not hematopoietic-derived, is reshaping our knowledge about the isolated role of microglia in CNS diseases, including degenerative conditions of the retina. However, unraveling microglial-specific functions has been hindered by phenotypic overlap of microglia with monocyte-derived macrophages. The latter are differentiated from recruited monocytes in neuroinflammation, including retina. Here we demonstrate the use of fate mapping wherein microglia and monocyte-derived cells are endogenously labeled with different fluorescent reporters. Combining this method with 12-color flow cytometry, we show that these two populations are definitively distinguishable by phenotype in retina. We prove that retinal microglia have a unique CD45(lo) CD11c(lo) F4/80(lo) I-A/I-E(-) signature, conserved in the steady state and during retinal injury. The latter was observed in the widely used light-induced retinal degeneration model and corroborated in other models, including whole-body irradiation/bone-marrow transplantation. The literature contains conflicting observations about whether microglia, including in the retina, increase expression of these markers in neuroinflammation. We show that monocyte-derived macrophages have elevated expression of these surface markers, not microglia. Our resolution of such phenotypic differences may serve as a robust way to help characterize isolated roles of these cells in retinal neuroinflammation and possibly elsewhere in CNS.
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Chakravarthy H, Beli E, Navitskaya S, O’Reilly S, Wang Q, Kady N, Huang C, Grant MB, Busik JV. Imbalances in Mobilization and Activation of Pro-Inflammatory and Vascular Reparative Bone Marrow-Derived Cells in Diabetic Retinopathy. PLoS One 2016; 11:e0146829. [PMID: 26760976 PMCID: PMC4711951 DOI: 10.1371/journal.pone.0146829] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/22/2015] [Indexed: 12/30/2022] Open
Abstract
Diabetic retinopathy is a sight-threatening complication of diabetes, affecting 65% of patients after 10 years of the disease. Diabetic metabolic insult leads to chronic low-grade inflammation, retinal endothelial cell loss and inadequate vascular repair. This is partly due to bone marrow (BM) pathology leading to increased activity of BM-derived pro-inflammatory monocytes and impaired function of BM-derived reparative circulating angiogenic cells (CACs). We propose that diabetes has a significant long-term effect on the nature and proportion of BM-derived cells that circulate in the blood, localize to the retina and home back to their BM niche. Using a streptozotocin mouse model of diabetic retinopathy with GFP BM-transplantation, we have demonstrated that BM-derived circulating pro-inflammatory monocytes are increased in diabetes while reparative CACs are trapped in the BM and spleen, with impaired release into circulation. Diabetes also alters activation of splenocytes and BM-derived dendritic cells in response to LPS stimulation. A majority of the BM-derived GFP cells that migrate to the retina express microglial markers, while others express endothelial, pericyte and Müller cell markers. Diabetes significantly increases infiltration of BM-derived microglia in an activated state, while reducing infiltration of BM-derived endothelial progenitor cells in the retina. Further, control CACs injected into the vitreous are very efficient at migrating back to their BM niche, whereas diabetic CACs have lost this ability, indicating that the in vivo homing efficiency of diabetic CACs is dramatically decreased. Moreover, diabetes causes a significant reduction in expression of specific integrins regulating CAC migration. Collectively, these findings indicate that BM pathology in diabetes could play a role in both increased pro-inflammatory state and inadequate vascular repair contributing to diabetic retinopathy.
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Affiliation(s)
- Harshini Chakravarthy
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Eleni Beli
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Svetlana Navitskaya
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Sandra O’Reilly
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Qi Wang
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Nermin Kady
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Chao Huang
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Maria B. Grant
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Julia V. Busik
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
- * E-mail:
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Chen M, Xu H. Parainflammation, chronic inflammation, and age-related macular degeneration. J Leukoc Biol 2015; 98:713-25. [PMID: 26292978 PMCID: PMC4733662 DOI: 10.1189/jlb.3ri0615-239r] [Citation(s) in RCA: 253] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 07/28/2015] [Indexed: 12/13/2022] Open
Abstract
Inflammation is an adaptive response of the immune system to noxious insults to maintain homeostasis and restore functionality. The retina is considered an immune-privileged tissue as a result of its unique anatomic and physiologic properties. During aging, the retina suffers from a low-grade chronic oxidative insult, which sustains for decades and increases in level with advancing age. As a result, the retinal innate-immune system, particularly microglia and the complement system, undergoes low levels of activation (parainflammation). In many cases, this parainflammatory response can maintain homeostasis in the healthy aging eye. However, in patients with age-related macular degeneration, this parainflammatory response becomes dysregulated and contributes to macular damage. Factors contributing to the dysregulation of age-related retinal parainflammation include genetic predisposition, environmental risk factors, and old age. Dysregulated parainflammation (chronic inflammation) in age-related macular degeneration damages the blood retina barrier, resulting in the breach of retinal-immune privilege, leading to the development of retinal lesions. This review discusses the basic principles of retinal innate-immune responses to endogenous chronic insults in normal aging and in age-related macular degeneration and explores the difference between beneficial parainflammation and the detrimental chronic inflammation in the context of age-related macular degeneration.
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Affiliation(s)
- Mei Chen
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, United Kingdom
| | - Heping Xu
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, United Kingdom
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Jiang G, Wang Y, Yun J, Hajrasouliha AR, Zhao Y, Sun D, Kaplan HJ, Shao H. HMGB1 release triggered by the interaction of live retinal cells and uveitogenic T cells is Fas/FasL activation-dependent. J Neuroinflammation 2015; 12:179. [PMID: 26394985 PMCID: PMC4579830 DOI: 10.1186/s12974-015-0389-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/02/2015] [Indexed: 11/29/2022] Open
Abstract
Background It is not clear how invading autoreactive T cells initiate the pathogenic process inside the diseased organ in T cell-mediated organ-specific autoimmune disease. In experimental autoimmune uveitis (EAU) induced by adoptive transfer of interphotoreceptor retinoid-binding protein (IRBP)-specific T cells in mice, we have previously reported that intraocular inflammation was initiated by infiltrating IRBP-specific T cells that directly interacted with retinal cells and resulted in the active release of high mobility group box 1 (HMGB1), an important member of damage associate molecular patterns (DAMPs). Furthermore, blockade of HMGB1 in our murine model reduced intraocular inflammation via suppression of IRBP-specific T cell functions. These results have demonstrated that HMGB1 is an early and critical mediator of induction of intraocular inflammation. The present study identified the cell surface molecule that triggers HMGB1 secretion. Methods Retinal explants from Fas-deficient (Faslpr) and wild-type (Wt) C57BL/6 (B6) mice were cultured with activated IRBP 1–20 peptide-specific T cells or with a Fas-activating antibody (Jo2), and then the level of HMGB1 in culture supernatants were detected by ELISA. In addition, released HMGB1 was examined in the eye of Faslpr and Wt mice after IRBP-specific T cell transfer. Uveitis was evaluated in the IRBP-specific T cell transferred Faslpr mice after recombinant HMGB1 was restored within the eye and in the IRBP-specific T cell transferred Wt mice after they were treated with a Fas antagonist (Met12). Results In contrast to retinal explants from Wt mice, those from Faslpr mice did not release HMGB1 after exposure to IRBP-specific T cells or to Jo2. The release of HMGB1 by Wt retinal explants was suppressed by Met 12. Moreover, after IRBP-specific T cell injection, Faslpr mice did not release HMGB1 in the eye or develop EAU, but intravitreous injection of HMGB1 resulted in intraocular inflammation. Finally, tEAU in Wt mice was attenuated by local treatment with Met 12. Unlike HMGB1, Fas-induced IL-1 and IL-18 were not essential for tEAU induction. Conclusion Our results show that interaction of retinal cells with infiltrating uveitogenic T cells leads to rapid release of HMGB1 via the Fas/FasL inflammatory signaling pathway.
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Affiliation(s)
- Guomin Jiang
- Department of Ophthalmology and Visual Sciences, Kentucky Lions Eye Center, University of Louisville, 301 E. Muhammad Ali Blvd., Louisville, KY, 40202, USA
| | - Yunsong Wang
- Department of Ophthalmology and Visual Sciences, Kentucky Lions Eye Center, University of Louisville, 301 E. Muhammad Ali Blvd., Louisville, KY, 40202, USA.,Department of Ophthalmology, Tangshan Gongren Hospital, Tangshan, Hebei, 063000, China
| | - Juan Yun
- Department of Ophthalmology and Visual Sciences, Kentucky Lions Eye Center, University of Louisville, 301 E. Muhammad Ali Blvd., Louisville, KY, 40202, USA.,Department of Pharmaceutical Sciences, Sullivan University College of Pharmacy, Louisville, KY, 40205, USA
| | - Amir Reza Hajrasouliha
- Department of Ophthalmology and Visual Sciences, Kentucky Lions Eye Center, University of Louisville, 301 E. Muhammad Ali Blvd., Louisville, KY, 40202, USA
| | - Yuan Zhao
- Department of Pharmaceutical Sciences, Sullivan University College of Pharmacy, Louisville, KY, 40205, USA
| | - Deming Sun
- Doheny Eye Institute, Los Angeles, CA, 90033, USA
| | - Henry J Kaplan
- Department of Ophthalmology and Visual Sciences, Kentucky Lions Eye Center, University of Louisville, 301 E. Muhammad Ali Blvd., Louisville, KY, 40202, USA
| | - Hui Shao
- Department of Ophthalmology and Visual Sciences, Kentucky Lions Eye Center, University of Louisville, 301 E. Muhammad Ali Blvd., Louisville, KY, 40202, USA.
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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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Nickells RW, Pelzel HR. Tools and resources for analyzing gene expression changes in glaucomatous neurodegeneration. Exp Eye Res 2015; 141:99-110. [PMID: 25999234 DOI: 10.1016/j.exer.2015.05.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 05/10/2015] [Accepted: 05/17/2015] [Indexed: 01/12/2023]
Abstract
Evaluating gene expression changes presents one of the most powerful interrogative approaches to study the molecular, biochemical, and cellular pathways associated with glaucomatous disease pathology. Technologies to study gene expression profiles in glaucoma are wide ranging. Qualitative techniques provide the power of localizing expression changes to individual cells, but are not robust to evaluate differences in expression changes. Alternatively, quantitative changes provide a high level of stringency to quantify changes in gene expression. Additionally, advances in high throughput analysis and bioinformatics have dramatically improved the number of individual genes that can be evaluated in a single experiment, while dramatically reducing amounts of input tissue/starting material. Together, gene expression profiling and proteomics have yielded new insights on the roles of neuroinflammation, the complement cascade, and metabolic shutdown as important players in the pathology of the optic nerve head and retina in this disease.
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Affiliation(s)
- Robert W Nickells
- Department of Ophthalmology and Visual Sciences, University of Wisconsin - Madison, Madison, WI, USA; McPherson Eye Research Institute, University of Wisconsin - Madison, Madison, WI, USA.
| | - Heather R Pelzel
- Department of Biological Sciences, University of Wisconsin - Whitewater, Whitewater, WI, USA
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Schuld NJ, Hussong SA, Kapphahn RJ, Lehmann U, Roehrich H, Rageh AA, Heuss ND, Bratten W, Gregerson DS, Ferrington DA. Immunoproteasome deficiency protects in the retina after optic nerve crush. PLoS One 2015; 10:e0126768. [PMID: 25978061 PMCID: PMC4433222 DOI: 10.1371/journal.pone.0126768] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 04/07/2015] [Indexed: 01/31/2023] Open
Abstract
The immunoproteasome is upregulated by disease, oxidative stress, and inflammatory cytokines, suggesting an expanded role for the immunoproteasome in stress signaling that goes beyond its canonical role in generating peptides for antigen presentation. The signaling pathways that are regulated by the immunoproteasome remain elusive. However, previous studies suggest a role for the immunoproteasome in the regulation of PTEN and NF-κB signaling. One well-known pathway upstream of NF-κB and downstream of PTEN is the Akt signaling pathway, which is responsible for mediating cellular survival and is modulated after optic nerve crush (ONC). This study investigated the role of retinal immunoproteasome after injury induced by ONC, focusing on the Akt cell survival pathway. Retinas or retinal pigment epithelial (RPE) cells from wild type (WT) and knockout (KO) mice lacking either one (LMP2) or two (LMP7 and MECL-1) catalytic subunits of the immunoproteasome were utilized in this study. We show that mRNA and protein levels of the immunoproteasome subunits are significantly upregulated in WT retinas following ONC. Mice lacking the immunoproteasome subunits show either a delayed or dampened apoptotic response as well as altered Akt signaling, compared to WT mice after ONC. Treatment of the RPE cells with insulin growth factor-1 (IGF-1) to stimulate Akt signaling confirmed that the immunoproteasome modulates this pathway, and most likely modulates parallel pathways as well. This study links the inducible expression of the immunoproteasome following retinal injury to Akt signaling, which is important in many disease pathways.
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Affiliation(s)
- Nathan J. Schuld
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Stacy A. Hussong
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
- Graduate Program in Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Rebecca J. Kapphahn
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Ute Lehmann
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
- Graduate Program in Microbiology, Immunology and Cancer Biology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Heidi Roehrich
- Histology Core for Vision Research, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Abrar A. Rageh
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Neal D. Heuss
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Wendy Bratten
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Dale S. Gregerson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Deborah A. Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail:
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Silver PB, Silver P, Horai R, Chen J, Jittayasothorn Y, Chan CC, Villasmil R, Kesen MR, Caspi RR. Retina-specific T regulatory cells bring about resolution and maintain remission of autoimmune uveitis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2015; 194:3011-9. [PMID: 25716996 PMCID: PMC4459505 DOI: 10.4049/jimmunol.1402650] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Experimental autoimmune uveitis (EAU) induced in mice by immunization with the retinal Ag interphotoreceptor retinoid-binding protein (IRBP) is a model of human autoimmune uveitis. We examined whether T regulatory cells (Tregs) found in uveitic eyes are IRBP specific, functionally suppressive, and play a role in natural resolution of disease and in maintenance of remission. Progressive increase of Foxp3(+) Treg to T effector cell (Teff) ratio in uveitic eyes correlated with resolution of disease. At peak disease, up to 20% of Tregs (CD4(+)Foxp3(+)) and up to 60% of Teffs (CD4(+)Foxp3(-)) were IRBP specific, whereas in lymphoid organs retina-specific T cells were undetectable. Tregs isolated from eyes of mice with EAU efficiently suppressed IRBP-specific responses of Teffs from the same eyes. Importantly, systemic depletion of Tregs at peak disease delayed resolution of EAU, and their depletion after resolution triggered a relapse. This could be partially duplicated by depletion of Tregs locally within the eye. Thus, the T cell infiltrate in uveitic eyes of normal mice with a polyclonal T cell repertoire is highly enriched in IRBP-specific Tregs and Teffs. Unlike what has been reported for Tregs in other inflammatory sites, Tregs from uveitic eyes appear unimpaired functionally. Finally, Foxp3(+) Tregs play a role in the natural resolution of uveitis and in the maintenance of remission, which occurs at least in part through an effect that is local to the eye.
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Affiliation(s)
- Phyllis B Silver
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892
| | - Phyllis Silver
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892
| | - Reiko Horai
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892
| | - Jun Chen
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892; State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510275, China; and
| | - Yingyos Jittayasothorn
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892
| | - Chi-Chao Chan
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892
| | - Rafael Villasmil
- Flow Cytometry Core, National Eye Institute, National Institutes of Health, Bethesda, MD 20892
| | - Muge R Kesen
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892
| | - Rachel R Caspi
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892;
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McPherson SW, Heuss ND, Pierson MJ, Gregerson DS. Retinal antigen-specific regulatory T cells protect against spontaneous and induced autoimmunity and require local dendritic cells. J Neuroinflammation 2014; 11:205. [PMID: 25498509 PMCID: PMC4268905 DOI: 10.1186/s12974-014-0205-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 11/20/2014] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND We previously reported that the peripheral regulatory T cells (pTregs) generated 'on-demand' in the retina were crucial to retinal immune privilege, and in vitro analysis of retinal dendritic cells (DC) showed they possessed antigen presenting cell (APC) activity that promoted development of the Tregs and effector T cells (Teffs). Here, we expanded these findings by examining whether locally generated, locally acting pTregs were protective against spontaneous autoimmunity and autoimmunity mediated by interphotoreceptor retinoid-binding protein (IRBP). We also examined the APC capacity of retinal DC in vivo. METHODS Transgenic (Tg) mice expressing diphtheria toxin receptor (DTR) and/or green fluorescent protein (GFP) under control of the endogenous FoxP3 promoter (GFP only in FG mice, GFP and DTR in FDG mice) or the CD11c promoter (GFP and DTR in CDG mice) were used in conjunction with Tg mice expressing beta-galactosidase (βgal) as retinal neo-self antigen and βgal-specific TCR Tg mice (BG2). Retinal T cell responses were assayed by flow cytometry and retinal autoimmune disease assessed by histological examination. RESULTS Local depletion of the Tregs enhanced actively induced experimental autoimmune uveoretinitis to the highly expressed retinal self-antigen IRBP in FDG mice and spontaneous autoimmunity in βgal-FDG-BG2 mice, but not in mice lacking autoreactive T cells or their target antigen in the retina. The presence of retinal βgal downregulated the generation of antigen-specific Teffs and pTregs within the retina in response to local βgal challenge. Retinal DC depletion prevented generation of Tregs and Teffs within retina after βgal injection. Microglia remaining after DC depletion did not make up for loss of DC-dependent antigen presentation. CONCLUSIONS Our results suggest that local retinal Tregs protect against spontaneous organ-specific autoimmunity and that T cell responses within the retina require the presence of local DC.
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Affiliation(s)
- Scott W McPherson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Rm, 310, Lion's Research Bldg,,2001 6th St, SE,, Minneapolis 55455-3007, Minnesota, USA.
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Mac Nair CE, Fernandes KA, Schlamp CL, Libby RT, Nickells RW. Tumor necrosis factor alpha has an early protective effect on retinal ganglion cells after optic nerve crush. J Neuroinflammation 2014; 11:194. [PMID: 25407441 PMCID: PMC4245774 DOI: 10.1186/s12974-014-0194-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 11/03/2014] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Glaucoma is an optic neuropathy that is characterized by the loss of retinal ganglion cells (RGCs) initiated by damage to axons in the optic nerve. The degeneration and death of RGCs has been thought to occur in two waves. The first is axogenic, caused by direct insult to the axon. The second is somatic, and is thought to be caused by the production of inflammatory cytokines from the activated retinal innate immune cells. One of the cytokines consistently linked to glaucoma and RGC damage has been TNFα. Despite strong evidence implicating this protein in neurodegeneration, a direct injection of TNFα does not mimic the rapid loss of RGCs observed after acute optic nerve trauma or exposure to excitotoxins. This suggests that our understanding of TNFα signaling is incomplete. METHODS RGC death was induced by optic nerve crush in mice. The role of TNFα in this process was examined by quantitative PCR of Tnfα gene expression, and quantification of cell loss in Tnfα (-/-) mice or in wild-type animals receiving an intraocular injection of exongenous TNFα either before or after crush. Signaling pathways downstream of TNFα were examined by immunolabeling for JUN protein accumulation or activation of EGFP expression in NFκB reporter mice. RESULTS Optic nerve crush caused a modest increase in Tnfα gene expression, with kinetics similar to the activation of both macroglia and microglia. A pre-injection of TNFα attenuated ganglion cell loss after crush, while ganglion cell loss was more severe in Tnfα (-/-) mice. Conversely, over the long term, a single exposure to TNFα induced extrinsic apoptosis in RGCs. Müller cells responded to exogenous TNFα by accumulating JUN and activating NFκB. CONCLUSION Early after optic nerve crush, TNFα appears to have a protective role for RGCs, which may be mediated through Müller cells.
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Affiliation(s)
- Caitlin E Mac Nair
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, 571A MSC - 1300 University Ave., Madison, WI, 53706, USA. .,Cellular and Molecular Pathology Graduate Program, University of Wisconsin, 3170-10 K/L MFCB - 1685 Highland Ave., Madison, WI, 53705, USA.
| | - Kimberly A Fernandes
- Flaum Eye Institute, University of Rochester Medical Center, 601 Elmwood Ave., Box 659, Rochester, NY, 14642, USA.
| | - Cassandra L Schlamp
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, 571A MSC - 1300 University Ave., Madison, WI, 53706, USA.
| | - Richard T Libby
- Flaum Eye Institute, University of Rochester Medical Center, 601 Elmwood Ave., Box 659, Rochester, NY, 14642, USA. .,Department of Biomedical Genetics, University of Rochester Medical Center, 601 Elmwood Ave., Box 633, Rochester, NY, 14642, USA. .,The Center for Visual Sciences, University of Rochester Medical Center, 274 Meliora Hall, RC Box 270270, Rochester, NY, 14627, USA.
| | - Robert W Nickells
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, 571A MSC - 1300 University Ave., Madison, WI, 53706, USA.
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Heuss ND, Pierson MJ, Montaniel KRC, McPherson SW, Lehmann U, Hussong SA, Ferrington DA, Low WC, Gregerson DS. Retinal dendritic cell recruitment, but not function, was inhibited in MyD88 and TRIF deficient mice. J Neuroinflammation 2014; 11:143. [PMID: 25116321 PMCID: PMC4149240 DOI: 10.1186/s12974-014-0143-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Accepted: 07/29/2014] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Immune system cells are known to affect loss of neurons due to injury or disease. Recruitment of immune cells following retinal/CNS injury has been shown to affect the health and survival of neurons in several models. We detected close, physical contact between dendritic cells and retinal ganglion cells following an optic nerve crush, and sought to understand the underlying mechanisms. METHODS CD11c-DTR/GFP mice producing a chimeric protein of diphtheria toxin receptor (DTR) and GFP from a transgenic CD11c promoter were used in conjunction with mice deficient in MyD88 and/or TRIF. Retinal ganglion cell injury was induced by an optic nerve crush, and the resulting interactions of the GFPhi cells and retinal ganglion cells were examined. RESULTS Recruitment of GFPhi dendritic cells to the retina was significantly compromised in MyD88 and TRIF knockout mice. GFPhi dendritic cells played a significant role in clearing fluorescent-labeled retinal ganglion cells post-injury in the CD11c-DTR/GFP mice. In the TRIF and MyD88 deficient mice, the resting level of GFPhi dendritic cells was lower, and their influx was reduced following the optic nerve crush injury. The reduction in GFPhi dendritic cell numbers led to their replacement in the uptake of fluorescent-labeled debris by GFPlo microglia/macrophages. Depletion of GFPhi dendritic cells by treatment with diphtheria toxin also led to their displacement by GFPlo microglia/macrophages, which then assumed close contact with the injured neurons. CONCLUSIONS The contribution of recruited cells to the injury response was substantial, and regulated by MyD88 and TRIF. However, the presence of these adaptor proteins was not required for interaction with neurons, or the phagocytosis of debris. The data suggested a two-niche model in which resident microglia were maintained at a constant level post-optic nerve crush, while the injury-stimulated recruitment of dendritic cells and macrophages led to their transient appearance in numbers equivalent to or greater than the resident microglia.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Dale S Gregerson
- Department of Ophthalmology & Visual Neurosciences, University of Minnesota, Lions Research Bldg, Rm 314, 2001 6th St SE, Minneapolis 55455, MN, USA.
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Potential Sources and Roles of Adaptive Immunity in Age-Related Macular Degeneration: Shall We Rename AMD into Autoimmune Macular Disease? Autoimmune Dis 2014; 2014:532487. [PMID: 24876950 PMCID: PMC4022009 DOI: 10.1155/2014/532487] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/25/2014] [Accepted: 01/30/2014] [Indexed: 01/05/2023] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of vision loss in the elderly throughout the industrialized world. Its most prominent pathologic features are lesions involving the retinal pigment epithelium (RPE) the Bruch's membrane, the degeneration of photoreceptors, and, in the most aggressive cases, choroidal neovascularization.
Genetic associations between the risk of developing AMD and polymorphism within components of the complement system, as well as chemokine receptors expressed on microglial cells and macrophages, have linked retinal degeneration and choroidal neovascularization to innate immunity (inflammation). In addition to inflammation, players of the adaptive immunity including cytokines, chemokines, antibodies, and T cells have been detected in animal models of AMD and in patients suffering from this pathology. These observations suggest that adaptive immunity might play a role in different processes associated with AMD such as RPE atrophy, neovascularization, and retinal degeneration. To this date however, the exact roles (if any) of autoantibodies and T cells in AMD remain unknown. In this review we discuss the potential effects of adaptive immune responses in AMD pathogenesis.
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