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Wieghofer P, Engelbert M, Chui TYP, Rosen RB, Sakamoto T, Sebag J. Hyalocyte origin, structure, and imaging. EXPERT REVIEW OF OPHTHALMOLOGY 2022; 17:233-248. [PMID: 36632192 PMCID: PMC9831111 DOI: 10.1080/17469899.2022.2100762] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Introduction Hyalocytes have been recognized as resident tissue macrophages of the vitreous body since the mid-19th century. Despite this, knowledge about their origin, turnover, and dynamics is limited. Areas covered Historically, initial studies on the origin of hyalocytes used light and electron microscopy. Modern investigations across species including rodents and humans will be described. Novel imaging is now available to study human hyalocytes in vivo. The shared ontogeny with retinal microglia and their eventual interdependence as well as differences will be discussed. Expert opinion Owing to a common origin as myeloid cells, hyalocytes and retinal microglia have similarities, but hyalocytes appear to be distinct as resident macrophages of the vitreous body.
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Affiliation(s)
- Peter Wieghofer
- Cellular Neuroanatomy, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Universitätsstraße 2, 86159 Augsburg, Germany,Corresponding authors: Peter Wieghofer. , J Sebag.
| | - Michael Engelbert
- Vitreous Retina Macula Consultants of New York, New York, NY 10022, USA.,LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, NY 10065, USA.,Department of Ophthalmology, New York University School of Medicine, New York, NY 10016, USA
| | - Toco YP Chui
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, New York; Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Richard B Rosen
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, New York; Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Taiji Sakamoto
- Department of Ophthalmology, Kagoshima University Graduate School of Medical and Dental Science, Kagoshima, Japan
| | - J Sebag
- Doheny Eye Institute, UCLA, Los Angeles, CA, USA.,Clinical Ophthalmology, Stein Eye Institute, Geffen School of Medicine, UCLA, Los Angeles, CA, USA.,VMR Institute for Vitreous Macula Retina, Huntington Beach, CA, USA.,Corresponding authors: Peter Wieghofer. , J Sebag.
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2
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Liu B, Hou Q, Ma Y, Han X. HIPK3 Mediates Inflammatory Cytokines and Oxidative Stress Markers in Monocytes in a Rat Model of Sepsis Through the JNK/c-Jun Signaling Pathway. Inflammation 2021; 43:1127-1142. [PMID: 32356246 DOI: 10.1007/s10753-020-01200-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Sepsis is a fetal immunological disorder and its complication worsens in the patients with hemodialysis which may increase the risk of death. In the present study, we aimed to investigate the effect of homeodomain-interacting protein kinase 3 (HIPK3) on inflammatory factors and oxidative stress markers in monocytes of rats with sepsis by regulating the c-Jun amino-terminal kinase (JNK)/c-Jun signaling pathway. A rat model of sepsis was initially established using cecal ligation and puncture (CLP) and was further identified by enlarged spleen tissues, inflammation, and oxidative stress. Monocytes were isolated from rats with CLP-induced sepsis. HIPK3 was observed to be downregulated while JUN was upregulated in monocytes from rats with CLP-induced sepsis. Furthermore, isolated monocytes were transduced with lentiviral vectors expressing HIPK3 or shRNA against HIPK3 to explore the effect of HIPK3 on viability and apoptosis of monocytes as well as inflammatory factors and oxidative stress markers. The obtained data exhibited that overexpression of HIPK3 or inhibition of the JNK signaling pathway enhanced proliferation, reduced apoptosis of monocytes, alleviated inflammation, and oxidative stress injury. Consistently, our results may provide evidence that HIPK3 could inhibit the JNK/c-Jun signaling pathway, thereby potentially retarding the progression of sepsis.
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Affiliation(s)
- Ben Liu
- Department of Clinical Laboratory, The Affiliated Huai'an No. 1 People's Hospital of Nanjing Medical University, No. 1 West Yellow River Road, Huai'an, 223300, Jiangsu, People's Republic of China
| | - Qiuyue Hou
- Department of Clinical Laboratory, Huaiyin Hospital of Huai'an City, 38 Beijing West Road, Huai'an, 223300, Jiangsu, People's Republic of China
| | - Yuhong Ma
- Department of Psychiatry, Huaian No. 3 People's Hospital, 272 Huaihai West Road, Huai'an, 223300, Jiangsu, People's Republic of China
| | - Xuehua Han
- Department of Clinical Laboratory, Huai'an Hospital Affiliated of Xuzhou Medical University, No. 62, Huaihai South Road, Huai'an, 223002, Jiangsu Province, People's Republic of China.
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3
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Boeck M, Thien A, Wolf J, Hagemeyer N, Laich Y, Yusuf D, Backofen R, Zhang P, Boneva S, Stahl A, Hilgendorf I, Agostini H, Prinz M, Wieghofer P, Schlunck G, Schlecht A, Lange C. Temporospatial distribution and transcriptional profile of retinal microglia in the oxygen‐induced retinopathy mouse model. Glia 2020; 68:1859-1873. [DOI: 10.1002/glia.23810] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 02/12/2020] [Accepted: 02/19/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Myriam Boeck
- Eye Center, Medical Center, Faculty of MedicineUniversity of Freiburg Freiburg im Breisgau Germany
| | - Adrian Thien
- Eye Center, Medical Center, Faculty of MedicineUniversity of Freiburg Freiburg im Breisgau Germany
| | - Julian Wolf
- Eye Center, Medical Center, Faculty of MedicineUniversity of Freiburg Freiburg im Breisgau Germany
| | - Nora Hagemeyer
- Institute of Neuropathology, Faculty of MedicineUniversity of Freiburg Freiburg im Breisgau Germany
| | - Yannik Laich
- Eye Center, Medical Center, Faculty of MedicineUniversity of Freiburg Freiburg im Breisgau Germany
| | - Dilmurat Yusuf
- Department of BioinformaticsUniversity of Freiburg Freiburg im Breisgau Germany
| | - Rolf Backofen
- Department of BioinformaticsUniversity of Freiburg Freiburg im Breisgau Germany
| | - Peipei Zhang
- Eye Center, Medical Center, Faculty of MedicineUniversity of Freiburg Freiburg im Breisgau Germany
| | - Stefaniya Boneva
- Eye Center, Medical Center, Faculty of MedicineUniversity of Freiburg Freiburg im Breisgau Germany
| | - Andreas Stahl
- Department of OphthalmologyUniversity Medical Center Greifswald Greifswald Germany
| | - Ingo Hilgendorf
- Cardiology and AngiologyUniversity Heart Center, University of Freiburg Freiburg im Breisgau Germany
| | - Hansjürgen Agostini
- Eye Center, Medical Center, Faculty of MedicineUniversity of Freiburg Freiburg im Breisgau Germany
| | - Marco Prinz
- Institute of Neuropathology, Faculty of MedicineUniversity of Freiburg Freiburg im Breisgau Germany
- Signalling Research Centres BIOSS and CIBSSUniversity of Freiburg Freiburg im Breisgau Germany
- Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of MedicineUniversity of Freiburg Freiburg im Breisgau Germany
| | - Peter Wieghofer
- Institute of AnatomyUniversity of Leipzig Freiburg im Breisgau Germany
| | - Günther Schlunck
- Eye Center, Medical Center, Faculty of MedicineUniversity of Freiburg Freiburg im Breisgau Germany
| | - Anja Schlecht
- Eye Center, Medical Center, Faculty of MedicineUniversity of Freiburg Freiburg im Breisgau Germany
| | - Clemens Lange
- Eye Center, Medical Center, Faculty of MedicineUniversity of Freiburg Freiburg im Breisgau Germany
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4
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Kezic JM, Chrysostomou V, McMenamin PG, Crowston JG. Effects of age on retinal macrophage responses to acute elevation of intraocular pressure. Exp Eye Res 2020; 193:107995. [PMID: 32156653 DOI: 10.1016/j.exer.2020.107995] [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: 11/18/2019] [Revised: 01/17/2020] [Accepted: 03/05/2020] [Indexed: 11/25/2022]
Abstract
There is accumulating evidence that aging shifts the central nervous system milieu towards a proinflammatory state, with increased reactivity of microglia in the aging eye and brain having been implicated in the development of age-related neurodegenerative conditions. Indeed, alterations to microglial morphology and function have been recognized as a part of normal aging. Here, we sought to assess the effects of age on the retinal microglial and macrophage response to acute intraocular pressure (IOP) elevation. Further, we performed experiments whereby bone marrow from young or middle-aged mice was used to reconstitute the bone marrow of whole-body irradiated 12 month old mice. Bone marrow chimeric mice then underwent cannulation and IOP elevation 8 weeks after whole-body irradiation and bone marrow transplantation in order to determine whether the age of bone marrow alters the macrophage response to retinal injury. Our data show retinal macrophage reactivity and microglial morphological changes were enhanced in older mice when compared to younger mice in response to injury. When IOP elevation was performed after whole-body irradiation and bone marrow rescue, we noted subretinal macrophage accumulation and glial reactivity was reduced compared to non-irradiated mice that had also undergone IOP elevation. This effect was evident in both groups of chimeric mice that had received either young or middle-aged bone marrow, suggesting irradiation itself may alter the macrophage and glial response to injury rather than the age of bone marrow.
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Affiliation(s)
- Jelena M Kezic
- Centre for Eye Research Australia, Department of Ophthalmology, University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne Street, East Melbourne, Victoria, 3002, Australia; Department of Anatomy and Developmental Biology, Monash University, Wellington Road, Clayton, Victoria, 3800, Australia.
| | - Vicki Chrysostomou
- Centre for Eye Research Australia, Department of Ophthalmology, University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne Street, East Melbourne, Victoria, 3002, Australia.
| | - Paul G McMenamin
- Department of Anatomy and Developmental Biology, Monash University, Wellington Road, Clayton, Victoria, 3800, Australia.
| | - Jonathan G Crowston
- Centre for Eye Research Australia, Department of Ophthalmology, University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne Street, East Melbourne, Victoria, 3002, Australia.
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5
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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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6
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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: 46] [Impact Index Per Article: 7.7] [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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7
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Sasaki F, Koga T, Ohba M, Saeki K, Okuno T, Ishikawa K, Nakama T, Nakao S, Yoshida S, Ishibashi T, Ahmadieh H, Kanavi MR, Hafezi-Moghadam A, Penninger JM, Sonoda KH, Yokomizo T. Leukotriene B4 promotes neovascularization and macrophage recruitment in murine wet-type AMD models. JCI Insight 2018; 3:96902. [PMID: 30232269 DOI: 10.1172/jci.insight.96902] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 08/07/2018] [Indexed: 12/18/2022] Open
Abstract
Age-related macular degeneration (AMD), a progressive chronic disease of the central retina, is associated with aging and is a leading cause of blindness worldwide. Here, we demonstrate that leukotriene B4 (LTB4) receptor 1 (BLT1) promotes laser-induced choroidal neovascularization (CNV) in a mouse model for wet-type AMD. CNV was significantly less in BLT1-deficient (BLT1-KO) mice compared with BLT1-WT controls. Expression of several proangiogenic and profibrotic factors was lower in BLT1-KO eyes than in BLT1-WT eyes. LTB4 production in the eyes was substantially increased in the early phase after laser injury. BLT1 was highly expressed in M2 macrophages in vitro and in vivo, and ocular BLT1+ M2 macrophages were increased in the aged eyes after laser injury. Furthermore, M2 macrophages were rapidly attracted by LTB4 and subsequently produced VEGF-A- through BLT1-mediated signaling. Consequently, intravitreal injection of M2 macrophages augmented CNV formation, which was attenuated by BLT1 deficiency. Thus, laser-induced injury to the retina triggered LTB4 production and attracted M2 macrophages via BLT1, leading to development of CNV. A selective BLT1 antagonist (CP105696) and 3 LTB4 inhibitors (zileuton, MK-886, and bestatin) reduced CNV in a dose-dependent manner. CP105696 also inhibited the accumulation of BLT1+ M2 macrophages in the laser-injured eyes of aged mice. Together, these results indicate that the LTB4-BLT1 axis is a potentially novel therapeutic target for CNV of wet-type AMD.
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Affiliation(s)
- Fumiyuki Sasaki
- Department of Biochemistry, Juntendo University School of Medicine, Tokyo, Japan
| | - Tomoaki Koga
- Department of Biochemistry, Juntendo University School of Medicine, Tokyo, Japan
| | - Mai Ohba
- Department of Biochemistry, Juntendo University School of Medicine, Tokyo, Japan
| | - Kazuko Saeki
- Department of Biochemistry, Juntendo University School of Medicine, Tokyo, Japan
| | - Toshiaki Okuno
- Department of Biochemistry, Juntendo University School of Medicine, Tokyo, Japan
| | - Keijiro Ishikawa
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takahito Nakama
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shintaro Nakao
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shigeo Yoshida
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tatsuro Ishibashi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hamid Ahmadieh
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mozhgan Rezaei Kanavi
- Ocular Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ali Hafezi-Moghadam
- Molecular Biomarkers Nano-Imaging Laboratory, Brigham & Women's Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Josef M Penninger
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - Koh-Hei Sonoda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takehiko Yokomizo
- Department of Biochemistry, Juntendo University School of Medicine, Tokyo, Japan
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8
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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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9
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Chinnery HR, McMenamin PG, Dando SJ. Macrophage physiology in the eye. Pflugers Arch 2017; 469:501-515. [DOI: 10.1007/s00424-017-1947-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 01/29/2017] [Accepted: 01/31/2017] [Indexed: 10/20/2022]
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10
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[Macrophages : Causing ocular metastasis or immune reaction on tumor cells in the eye?]. Ophthalmologe 2016; 113:1092-1094. [PMID: 27888302 DOI: 10.1007/s00347-016-0400-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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11
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Friend or Foe? Resident Microglia vs Bone Marrow-Derived Microglia and Their Roles in the Retinal Degeneration. Mol Neurobiol 2016; 54:4094-4112. [PMID: 27318678 DOI: 10.1007/s12035-016-9960-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 06/06/2016] [Indexed: 01/10/2023]
Abstract
Microglia are immune cells in the central nervous system (CNS) that originate from the yolk sac in an embryo. The renewal of the microglia pool in the adult eye consists of two components. In addition to the self-proliferation of resident cells, microglia in the CNS also derive from the bone marrow (BM). BM-derived cells pass through the blood-brain barrier (BBB) or blood-retina barrier (BRB) and differentiate into microglia under specific conditions which involves a complex mechanism. Recent studies have widely investigated the role of resident microglia and BM-derived microglia in the retinal degenerative disease. Both two cell types play dual roles and share many similar functions. However, resident microglia tend to polarize to the M1 phenotype which is pro-inflammatory and neurotoxic, whereas BM-derived microglia mainly polarize to the neuroprotective M2 phenotype in retinal degeneration. The molecular mechanism that underlines the invasion of peripheral cells has led to extensive discussions. In addition to the BBB and BRB disruption, many signaling pathways are involved in this process. Based on these studies, we discuss the roles of these two types of microglia in retinal degeneration disease and the potential clinical application of BM-derived microglia, which may benefit future therapies.
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12
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Kohno H, Koso H, Okano K, Sundermeier TR, Saito S, Watanabe S, Tsuneoka H, Sakai T. Expression pattern of Ccr2 and Cx3cr1 in inherited retinal degeneration. J Neuroinflammation 2015; 12:188. [PMID: 26458944 PMCID: PMC4603985 DOI: 10.1186/s12974-015-0408-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 10/02/2015] [Indexed: 12/27/2022] Open
Abstract
Background Though accumulating evidence suggests that microglia, resident macrophages in the retina, and bone marrow-derived macrophages can cause retinal inflammation which accelerates photoreceptor cell death, the details of how these cells are activated during retinal degeneration (RD) remain uncertain. Therefore, it is important to clarify which cells play a dominant role in fueling retinal inflammation. However, distinguishing between microglia and macrophages is difficult using conventional techniques such as cell markers (e.g., Iba-1). Recently, two mouse models for visualizing chemokine receptors were established, Cx3cr1GFP/GFP and Ccr2RFP/RFP mice. As Cx3cr1 is expressed in microglia and Ccr2 is reportedly expressed in activated macrophages, these mice have the potential to distinguish microglia and macrophages, yielding novel information about the activation of these inflammatory cells and their individual roles in retinal inflammation. Methods In this study, c-mer proto-oncogene tyrosine kinase (Mertk)−/− mice, which show photoreceptor cell death due to defective retinal pigment epithelium phagocytosis, were employed as an animal model of RD. Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice were established by breeding Mertk−/−, Cx3cr1GFP/GFP, and Ccr2RFP/RFP mice. The retinal morphology and pattern of inflammatory cell activation and invasion of Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice were evaluated using retina and retinal pigment epithelium (RPE) flat mounts, retinal sections, and flow cytometry. Results Four-week-old Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice showed Cx3cr1-GFP-positive microglia in the inner retina. Cx3cr1-GFP and Ccr2-RFP dual positive activated microglia were observed in the outer retina and subretinal space of 6- and 8-week-old animals. Ccr2-RFP single positive bone marrow-derived macrophages were observed to migrate into the retina of Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice. These invading cells were still observed in the subretinal space in 18-week-old animals. Conclusions Cx3cr1-GFP-positive microglia and Ccr2-RFP-positive macrophages were distinguishable in the retinas of Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice. In addition, Ccr2 expression in Cx3cr1 positive microglia is a feature of microglial activation in RD. Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice enabled observation of microglial activation over time during RD and may be useful for developing inflammation-targeted treatment strategies for RD in the future.
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Affiliation(s)
- Hideo Kohno
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan. .,Tokyu Hospital, 145-0062, Tokyo, Japan.
| | - Hideto Koso
- Division of Molecular and Developmental Biology, The Institute of Medical Science, The University of Tokyo, 108-8639, Tokyo, Japan
| | - Kiichiro Okano
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan
| | - Thomas R Sundermeier
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Saburo Saito
- Department of Molecular Immunology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan
| | - Sumiko Watanabe
- Division of Molecular and Developmental Biology, The Institute of Medical Science, The University of Tokyo, 108-8639, Tokyo, Japan
| | - Hiroshi Tsuneoka
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan
| | - Tsutomu Sakai
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan.
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13
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Krause TA, Alex AF, Engel DR, Kurts C, Eter N. VEGF-production by CCR2-dependent macrophages contributes to laser-induced choroidal neovascularization. PLoS One 2014; 9:e94313. [PMID: 24714223 PMCID: PMC3979804 DOI: 10.1371/journal.pone.0094313] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 03/15/2014] [Indexed: 12/24/2022] Open
Abstract
Age-related macular degeneration (AMD) is the most prevalent cause of blindness in the elderly, and its exsudative subtype critically depends on local production of vascular endothelial growth factor A (VEGF). Mononuclear phagocytes, such as macrophages and microglia cells, can produce VEGF. Their precursors, for example monocytes, can be recruited to sites of inflammation by the chemokine receptor CCR2, and this has been proposed to be important in AMD. To investigate the role of macrophages and CCR2 in AMD, we studied intracellular VEGF content in a laser-induced murine model of choroidal neovascularisation. To this end, we established a technique to quantify the VEGF content in cell subsets from the laser-treated retina and choroid separately. 3 days after laser, macrophage numbers and their VEGF content were substantially elevated in the choroid. Macrophage accumulation was CCR2-dependent, indicating recruitment from the circulation. In the retina, microglia cells were the main VEGF+ phagocyte type. A greater proportion of microglia cells contained VEGF after laser, and this was CCR2-independent. On day 6, VEGF-expressing macrophage numbers had already declined, whereas numbers of VEGF+ microglia cells remained increased. Other sources of VEGF detectable by flow cytometry included in dendritic cells and endothelial cells in both retina and choroid, and Müller cells/astrocytes in the retina. However, their VEGF content was not increased after laser. When we analyzed flatmounts of laser-treated eyes, CCR2-deficient mice showed reduced neovascular areas after 2 weeks, but this difference was not evident 3 weeks after laser. In summary, CCR2-dependent influx of macrophages causes a transient VEGF increase in the choroid. However, macrophages augmented choroidal neovascularization only initially, presumably because VEGF production by CCR2-independent eye cells prevailed at later time points. These findings identify macrophages as a relevant source of VEGF in laser-induced choroidal neovascularization but suggest that the therapeutic efficacy of CCR2-inhibition might be limited.
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Affiliation(s)
- Torsten A Krause
- Institute of Experimental Immunology, Rheinische Friedrich-Wilhelms-University, Bonn, Germany
| | - Anne F Alex
- Department of Ophthalmology, University of Münster, Münster, Germany
| | - Daniel R Engel
- Institute of Experimental Immunology, Rheinische Friedrich-Wilhelms-University, Bonn, Germany
| | - Christian Kurts
- Institute of Experimental Immunology, Rheinische Friedrich-Wilhelms-University, Bonn, Germany
| | - Nicole Eter
- Department of Ophthalmology, University of Münster, Münster, Germany
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