1
|
Shinozaki Y, Namekata K, Guo X, Harada T. Glial cells as a promising therapeutic target of glaucoma: beyond the IOP. FRONTIERS IN OPHTHALMOLOGY 2024; 3:1310226. [PMID: 38983026 PMCID: PMC11182302 DOI: 10.3389/fopht.2023.1310226] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 12/18/2023] [Indexed: 07/11/2024]
Abstract
Glial cells, a type of non-neuronal cell found in the central nervous system (CNS), play a critical role in maintaining homeostasis and regulating CNS functions. Recent advancements in technology have paved the way for new therapeutic strategies in the fight against glaucoma. While intraocular pressure (IOP) is the most well-known modifiable risk factor, a significant number of glaucoma patients have normal IOP levels. Because glaucoma is a complex, multifactorial disease influenced by various factors that contribute to its onset and progression, it is imperative that we consider factors beyond IOP to effectively prevent or slow down the disease's advancement. In the realm of CNS neurodegenerative diseases, glial cells have emerged as key players due to their pivotal roles in initiating and hastening disease progression. The inhibition of dysregulated glial function holds the potential to protect neurons and restore brain function. Consequently, glial cells represent an enticing therapeutic candidate for glaucoma, even though the majority of glaucoma research has historically concentrated solely on retinal ganglion cells (RGCs). In addition to the neuroprotection of RGCs, the proper regulation of glial cell function can also facilitate structural and functional recovery in the retina. In this review, we offer an overview of recent advancements in understanding the non-cell-autonomous mechanisms underlying the pathogenesis of glaucoma. Furthermore, state-of-the-art technologies have opened up possibilities for regenerating the optic nerve, which was previously believed to be incapable of regeneration. We will also delve into the potential roles of glial cells in the regeneration of the optic nerve and the restoration of visual function.
Collapse
Affiliation(s)
- Youichi Shinozaki
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Xiaoli Guo
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takayuki Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| |
Collapse
|
2
|
Karg MM, Moorefield M, Hoffmann E, Philipose H, Krasniqi D, Hoppe C, Shu DY, Shirahama S, Ksander BR, Saint-Geniez M. Microglia preserve visual function loss in the aging retina by supporting retinal pigment epithelial health. Immun Ageing 2023; 20:53. [PMID: 37838654 PMCID: PMC10576380 DOI: 10.1186/s12979-023-00358-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 06/23/2023] [Indexed: 10/16/2023]
Abstract
BACKGROUND Increased age is a risk factor for the development and progression of retinal diseases including age-related macular degeneration (AMD). Understanding the changes that occur in the eye due to aging is important in enhancing our understanding of AMD pathogenesis and the development of novel AMD therapies. Microglia, the resident brain and retinal immune cells are associated with both maintaining homeostasis and protection of neurons and loss of microglia homeostasis could be a significant player in age related neurodegeneration. One important characteristic of retinal aging is the migration of microglia from the inner to outer retina where they reside in the subretinal space (SRS) in contact with the retinal pigment epithelial (RPE) cells. The role of aged subretinal microglia is unknown. Here, we depleted microglia in aged C57/BL6 mice fed for 6 weeks with a chow containing PLX5622, a small molecule inhibitor of colony-stimulating factor-1 receptor (Csf1r) required for microglial survival. RESULTS The subretinal P2RY12 + microglia in aged mice displayed a highly amoeboid and activated morphology and were filled with autofluorescence droplets reminiscent of lipofuscin. TEM indicates that subretinal microglia actively phagocytize shed photoreceptor outer segments, one of the main functions of retinal pigmented epithelial cells. PLX5622 treatment depleted up to 90% of the retinal microglia and was associated with significant loss in visual function. Mice on the microglia depletion diet showed reduced contrast sensitivity and significantly lower electroretinogram for the c-wave, a measurement of RPE functionality, compared to age-matched controls. The loss of c-wave coincided with a loss of RPE cells and increased RPE swelling in the absence of microglia. CONCLUSIONS We conclude that microglia preserve visual function in aged mice and support RPE cell function, by phagocytosing shed photoreceptor outer segments and lipids, therefore compensating for the known age-related decline of RPE phagocytosis.
Collapse
Affiliation(s)
- Margarete M Karg
- Schepens Eye Research Institute of Mass Eye and Ear, 20 Staniford St, Boston, MA, 02114, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - May Moorefield
- Schepens Eye Research Institute of Mass Eye and Ear, 20 Staniford St, Boston, MA, 02114, USA
| | - Emma Hoffmann
- Schepens Eye Research Institute of Mass Eye and Ear, 20 Staniford St, Boston, MA, 02114, USA
| | - Hannah Philipose
- Schepens Eye Research Institute of Mass Eye and Ear, 20 Staniford St, Boston, MA, 02114, USA
| | - Drenushe Krasniqi
- Schepens Eye Research Institute of Mass Eye and Ear, 20 Staniford St, Boston, MA, 02114, USA
| | - Cindy Hoppe
- Schepens Eye Research Institute of Mass Eye and Ear, 20 Staniford St, Boston, MA, 02114, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Daisy Y Shu
- Schepens Eye Research Institute of Mass Eye and Ear, 20 Staniford St, Boston, MA, 02114, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Shintaro Shirahama
- Schepens Eye Research Institute of Mass Eye and Ear, 20 Staniford St, Boston, MA, 02114, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Bruce R Ksander
- Schepens Eye Research Institute of Mass Eye and Ear, 20 Staniford St, Boston, MA, 02114, USA.
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.
| | - Magali Saint-Geniez
- Schepens Eye Research Institute of Mass Eye and Ear, 20 Staniford St, Boston, MA, 02114, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
3
|
Zhou ZY, Chang TF, Lin ZB, Jing YT, Wen LS, Niu YL, Bai Q, Guo CM, Sun JX, Wang YS, Dou GR. Microglial Galectin3 enhances endothelial metabolism and promotes pathological angiogenesis via Notch inhibition by competitively binding to Jag1. Cell Death Dis 2023; 14:380. [PMID: 37369647 DOI: 10.1038/s41419-023-05897-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 05/26/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023]
Abstract
Microglia were considered as immune cells in inflammation until their angiogenic role was widely understood. Although the pro-inflammatory role of microglia in retinal angiogenesis has been explored, little is known about its role in pro-angiogenesis and the microglia-endothelia interaction. Here, we report that galectin-3 (Gal3) released by activated microglia functions as a communicator between microglia and endothelia and competitively binds to Jag1, thus inhibiting the Notch signaling pathway and enhancing endothelial angiogenic metabolism to promote angiogenesis. These results suggest that Gal3 may be a novel and effective target in the treatment of retinal angiogenesis.
Collapse
Affiliation(s)
- Zi-Yi Zhou
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Tian-Fang Chang
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Zhi-Bin Lin
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Yu-Tong Jing
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Li-Shi Wen
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Ya-Li Niu
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Qian Bai
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Chang-Mei Guo
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Jia-Xing Sun
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China.
| | - Yu-Sheng Wang
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China.
| | - Guo-Rui Dou
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China.
| |
Collapse
|
4
|
Murenu E, Gerhardt MJ, Biel M, Michalakis S. More than meets the eye: The role of microglia in healthy and diseased retina. Front Immunol 2022; 13:1006897. [PMID: 36524119 PMCID: PMC9745050 DOI: 10.3389/fimmu.2022.1006897] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 11/11/2022] [Indexed: 11/30/2022] Open
Abstract
Microglia are the main resident immune cells of the nervous system and as such they are involved in multiple roles ranging from tissue homeostasis to response to insults and circuit refinement. While most knowledge about microglia comes from brain studies, some mechanisms have been confirmed for microglia cells in the retina, the light-sensing compartment of the eye responsible for initial processing of visual information. However, several key pieces of this puzzle are still unaccounted for, as the characterization of retinal microglia has long been hindered by the reduced population size within the retina as well as the previous lack of technologies enabling single-cell analyses. Accumulating evidence indicates that the same cell type may harbor a high degree of transcriptional, morphological and functional differences depending on its location within the central nervous system. Thus, studying the roles and signatures adopted specifically by microglia in the retina has become increasingly important. Here, we review the current understanding of retinal microglia cells in physiology and in disease, with particular emphasis on newly discovered mechanisms and future research directions.
Collapse
Affiliation(s)
- Elisa Murenu
- Department of Ophthalmology, Klinikum der Ludwig-Maximilians-Universität München, Munich, Germany,*Correspondence: Elisa Murenu, ; ; Stylianos Michalakis,
| | | | - Martin Biel
- Department of Pharmacy, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Stylianos Michalakis
- Department of Ophthalmology, Klinikum der Ludwig-Maximilians-Universität München, Munich, Germany,*Correspondence: Elisa Murenu, ; ; Stylianos Michalakis,
| |
Collapse
|
5
|
Zhou Z, Jing Y, Niu Y, Chang T, Sun J, Guo C, Wang Y, Dou G. Distinguished Functions of Microglia in the Two Stages of Oxygen-Induced Retinopathy: A Novel Target in the Treatment of Ischemic Retinopathy. LIFE (BASEL, SWITZERLAND) 2022; 12:life12101676. [PMID: 36295111 PMCID: PMC9604577 DOI: 10.3390/life12101676] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/19/2022] [Accepted: 10/20/2022] [Indexed: 11/17/2022]
Abstract
Microglia is the resident immune cell in the retina, playing the role of immune surveillance in a traditional concept. With the heated focus on the mechanisms of microglia in pathological conditions, more and more functions of microglia have been discovered. Although the regulating role of microglia has been explored in ischemic retinopathy, little is known about its mechanisms in the different stages of the pathological process. Here, we removed microglia in the oxygen-induced retinopathy model by PLX5622 and revealed that the removal of activated microglia reduced pathological angiogenesis in the early stage after ischemic insult and alleviated the over-apoptosis of photoreceptors in the vessel remodeling phase. Our results indicated that microglia might play distinguished functions in the angiogenic and remodeling stages, and that the inhibition of microglia might be a promising target in the future treatment of ischemic retinopathy.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Yusheng Wang
- Correspondence: (Y.W.); (G.D.); Tel.: +86-029-84775371 (Y.W.); +86-029-84771273 (G.D.)
| | - Guorui Dou
- Correspondence: (Y.W.); (G.D.); Tel.: +86-029-84775371 (Y.W.); +86-029-84771273 (G.D.)
| |
Collapse
|
6
|
Funatsu J, Murakami Y, Shimokawa S, Nakatake S, Fujiwara K, Okita A, Fukushima M, Shibata K, Yoshida N, Koyanagi Y, Akiyama M, Notomi S, Nakao S, Hisatomi T, Takeda A, Paschalis EI, Vavvas DG, Ikeda Y, Sonoda KH. Circulating inflammatory monocytes oppose microglia and contribute to cone cell death in retinitis pigmentosa. PNAS NEXUS 2022; 1. [PMID: 35529318 DOI: 10.1093/pnasnexus/pgac003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Retinitis pigmentosa (RP) is an intractable inherited disease that primarily affects the rods through gene mutations followed by secondary cone degeneration. This cone-related dysfunction can lead to impairment of daily life activities, and ultimately blindness in patients with RP. Paradoxically, microglial neuroinflammation contributes to both protection against and progression of RP, but it is unclear which population(s) - tissue-resident microglia and/or peripheral monocyte-derived macrophages (mφ) - are implicated in the progression of the disease. Here we show that circulating blood inflammatory monocytes (IMo) are key effector cells that mediate cone cell death in RP. Attenuation of IMo and peripherally engrafted mφ by Ccl2 deficiency or immune modulation via intravenous nano-particle treatment suppressed cone cell death in rd10 mice, an animal model of RP. In contrast, the depletion of resident microglia by a colony-stimulating factor 1 receptor inhibitor exacerbated cone cell death in the same model. In human patients with RP, IMo was increased and correlated with disease progression. These results suggest that peripheral IMo is a potential target to delay cone cell death and prevent blindness in RP.
Collapse
Affiliation(s)
- Jun Funatsu
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Yusuke Murakami
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Shotaro Shimokawa
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Shunji Nakatake
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Kohta Fujiwara
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Ayako Okita
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Masatoshi Fukushima
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Kensuke Shibata
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan.,Department of Genomics and Molecular Analysis, Yamaguchi University School of Medicine, Yamaguchi 755-8505, Japan
| | - Noriko Yoshida
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan.,Department of Ophthalmology, Fukuoka Dental College Medical and Dental Hospital, Fukuoka 814-0193, Japan
| | - Yoshito Koyanagi
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Masato Akiyama
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan.,Department of Ocular Pathology and Imaging Science, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Shoji Notomi
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Shintaro Nakao
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Toshio Hisatomi
- Department of Ophthalmology, Chikushi Hospital, Fukuoka University, Fukuoka 818-8502, Japan
| | - Atsunobu Takeda
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Eleftherios I Paschalis
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.,Boston Keratoprosthesis Laboratory, Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.,Disruptive Technology Laboratory, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Demetrios G Vavvas
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.,Angiogenesis Laboratory, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Yasuhiro Ikeda
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan.,Department of Ophthalmology, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Koh-Hei Sonoda
- Department of Ophthalmology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| |
Collapse
|
7
|
Freuchet A, Salama A, Remy S, Guillonneau C, Anegon I. IL-34 and CSF-1, deciphering similarities and differences at steady state and in diseases. J Leukoc Biol 2021; 110:771-796. [PMID: 33600012 DOI: 10.1002/jlb.3ru1120-773r] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/04/2021] [Accepted: 01/04/2021] [Indexed: 12/11/2022] Open
Abstract
Although IL-34 and CSF-1 share actions as key mediators of monocytes/macrophages survival and differentiation, they also display differences that should be identified to better define their respective roles in health and diseases. IL-34 displays low sequence homology with CSF-1 but has a similar general structure and they both bind to a common receptor CSF-1R, although binding and subsequent intracellular signaling shows differences. CSF-1R expression has been until now mainly described at a steady state in monocytes/macrophages and myeloid dendritic cells, as well as in some cancers. IL-34 has also 2 other receptors, protein-tyrosine phosphatase zeta (PTPζ) and CD138 (Syndecan-1), expressed in some epithelium, cells of the central nervous system (CNS), as well as in numerous cancers. While most, if not all, of CSF-1 actions are mediated through monocyte/macrophages, IL-34 has also other potential actions through PTPζ and CD138. Additionally, IL-34 and CSF-1 are produced by different cells in different tissues. This review describes and discusses similarities and differences between IL-34 and CSF-1 at steady state and in pathological situations and identifies possible ways to target IL-34, CSF-1, and its receptors.
Collapse
Affiliation(s)
- Antoine Freuchet
- Centre de Recherche en Transplantation et Immunologie UMR1064, INSERM, Université de Nantes, Nantes, France.,Institut de Transplantation Urologie Néphrologie (ITUN), CHU Nantes, Nantes, France.,LabEx IGO "Immunotherapy, Graft, Oncology", Nantes, France
| | - Apolline Salama
- Centre de Recherche en Transplantation et Immunologie UMR1064, INSERM, Université de Nantes, Nantes, France.,Institut de Transplantation Urologie Néphrologie (ITUN), CHU Nantes, Nantes, France.,LabEx IGO "Immunotherapy, Graft, Oncology", Nantes, France
| | - Séverine Remy
- Centre de Recherche en Transplantation et Immunologie UMR1064, INSERM, Université de Nantes, Nantes, France.,Institut de Transplantation Urologie Néphrologie (ITUN), CHU Nantes, Nantes, France.,LabEx IGO "Immunotherapy, Graft, Oncology", Nantes, France
| | - Carole Guillonneau
- Centre de Recherche en Transplantation et Immunologie UMR1064, INSERM, Université de Nantes, Nantes, France.,Institut de Transplantation Urologie Néphrologie (ITUN), CHU Nantes, Nantes, France.,LabEx IGO "Immunotherapy, Graft, Oncology", Nantes, France
| | - Ignacio Anegon
- Centre de Recherche en Transplantation et Immunologie UMR1064, INSERM, Université de Nantes, Nantes, France.,Institut de Transplantation Urologie Néphrologie (ITUN), CHU Nantes, Nantes, France.,LabEx IGO "Immunotherapy, Graft, Oncology", Nantes, France
| |
Collapse
|
8
|
Schwarzer P, Kokona D, Ebneter A, Zinkernagel MS. Effect of Inhibition of Colony-Stimulating Factor 1 Receptor on Choroidal Neovascularization in Mice. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 190:412-425. [PMID: 31783006 DOI: 10.1016/j.ajpath.2019.10.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 07/09/2019] [Accepted: 10/21/2019] [Indexed: 12/15/2022]
Abstract
Neovascular age-related macular degeneration is one of the leading causes of blindness. Microglia and macrophages play a critical role in choroidal neovascularization (CNV) and may, therefore, be potential targets to modulate the disease course. This study evaluated the effect of the colony-stimulating factor-1 receptor inhibitor PLX5622 on experimental laser-induced CNV. A 98% reduction of retinal microglia cells was observed in the retina 1 week after initiation of PLX5622 treatment, preventing accumulation of macrophages within the laser site and leading to a reduction of leukocytes within the choroid after CNV induction. Mice treated with PLX5622 had a significantly faster decrease of the CNV lesion size, as revealed by in vivo imaging and immunohistochemistry from day 3 to day 14 compared with untreated mice. Several inflammatory modulators, such as chemokine (C-C motif) ligand 9, granulocyte-macrophage colony-stimulating factor, soluble tumor necrosis factor receptor-I, IL-1α, and matrix metallopeptidase-2, were elevated in the acute phase of the disease when microglia were ablated with PLX5622, whereas other cytokines (eg, interferon-γ, IL-4, and IL-10) were reduced. Our results suggest that colony-stimulating factor-1 receptor inhibition may be a novel therapeutic target in patients with neovascular age-related macular degeneration.
Collapse
Affiliation(s)
- Petra Schwarzer
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern; and the Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Despina Kokona
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern; and the Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Andreas Ebneter
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern; and the Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Martin S Zinkernagel
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern; and the Department for BioMedical Research, University of Bern, Bern, Switzerland.
| |
Collapse
|
9
|
Jovanovic J, Liu X, Kokona D, Zinkernagel MS, Ebneter A. Inhibition of inflammatory cells delays retinal degeneration in experimental retinal vein occlusion in mice. Glia 2019; 68:574-588. [PMID: 31652020 PMCID: PMC7003783 DOI: 10.1002/glia.23739] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/09/2019] [Accepted: 10/10/2019] [Indexed: 12/18/2022]
Abstract
The role of microglia in retinal inflammation is still ambiguous. Branch retinal vein occlusion initiates an inflammatory response whereby resident microglia cells are activated. They trigger infiltration of neutrophils that exacerbate blood–retina barrier damage, regulate postischemic inflammation and irreversible loss of neuroretina. Suppression of microglia‐mediated inflammation might bear potential for mitigating functional impairment after retinal vein occlusion (RVO). To test this hypothesis, we depleted microglia by PLX5622 (a selective tyrosine kinase inhibitor that targets the colony‐stimulating factor‐1 receptor) in fractalkine receptor reporter mice (Cx3cr1gfp/+) subjected to various regimens of PLX5622 treatment and experimental RVO. Effectiveness of microglia suppression and retinal outcomes including retinal thickness as well as ganglion cell survival were compared to a control group of mice with experimental vein occlusion only. PLX5622 caused dramatic suppression of microglia. Despite vein occlusion, reappearance of green fluorescent protein positive cells was strongly impeded with continuous PLX5622 treatment and significantly delayed after its cessation. In depleted mice, retinal proinflammatory cytokine signaling was diminished and retinal ganglion cell survival improved by almost 50% compared to nondepleted animals 3 weeks after vein occlusion. Optical coherence tomography suggested delayed retinal degeneration in depleted mice. In summary, findings indicate that suppression of cells bearing the colony‐stimulating factor‐1 receptor, mainly microglia and monocytes, mitigates ischemic damage and salvages retinal ganglion cells. Blood–retina barrier breakdown seems central in the disease mechanism, and complex interactions between different cell types composing the blood–retina barrier as well as sustained hypoxia might explain why the protective effect was only partial.
Collapse
Affiliation(s)
- Joël Jovanovic
- Department of Ophthalmology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.,Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Xuan Liu
- Department of Ophthalmology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.,Department of Ophthalmology, 1st Affiliated Hospital of Xi'an Jiaotong University, Xi'an Shaanxi, China
| | - Despina Kokona
- Department of Ophthalmology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.,Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Martin S Zinkernagel
- Department of Ophthalmology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.,Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Andreas Ebneter
- Department of Ophthalmology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.,Department for BioMedical Research, University of Bern, Bern, Switzerland
| |
Collapse
|
10
|
Abstract
Autoimmune uveitis is a sight-threatening ocular inflammatory condition in which the retina and uveal tissues become a target of autoreactive immune cells. While microglia have been studied extensively in autoimmune uveitis, their exact function remains uncertain. The objective of the current study was to determine whether resident microglia are necessary and sufficient to initiate and amplify retinal inflammation in autoimmune uveitis. In this study, we clearly demonstrate that microglia are essential for initiating infiltration of immune cells utilizing a murine model of experimental autoimmune uveoretinitis (EAU) and the recently identified microglia-specific marker P2ry12. Initiating disease is the primary function of microglia in EAU, since eliminating microglia during the later stages of EAU had little effect, indicating that the function of circulating leukocytes is to amplify and sustain destructive inflammation once microglia have triggered disease. In the absence of microglia, uveitis does not develop, since leukocytes cannot gain entry through the blood-retinal barrier, illustrating that microglia play a critical role in regulating infiltration of inflammatory cells into the retina.
Collapse
|
11
|
Kokona D, Ebneter A, Escher P, Zinkernagel MS. Colony-stimulating factor 1 receptor inhibition prevents disruption of the blood-retina barrier during chronic inflammation. J Neuroinflammation 2018; 15:340. [PMID: 30541565 PMCID: PMC6292111 DOI: 10.1186/s12974-018-1373-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 11/19/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Microglia-associated inflammation is closely related to the pathogenesis of various retinal diseases such as uveitis and diabetic retinopathy, which are associated with increased vascular permeability. In this study, we investigated the effect of systemic lipopolysaccharide (LPS) exposure to activation and proliferation of retinal microglia /macrophages. METHODS Balb/c and Cx3cr1gfp/+ mice were challenged with LPS (1 mg/kg) daily for four consecutive days. For microglia depletion, mice were treated with colony-stimulating factor 1 receptor (CSF-1R) inhibitor PLX5622 1 week before the first LPS challenge and until the end of the experiment. In vivo imaging of the retina was performed on days 4 and 7 after the first LPS challenge, using optical coherence tomography and fluorescein angiography. Flow cytometry analysis, retinal whole mount, and retinal sections were used to investigate microglia and macrophage infiltration and proliferation after LPS challenge. Cytokines were analyzed in the blood as well as in the retina. Data analysis was performed using unpaired t tests, repeated measures one-way ANOVA, or ordinary one-way ANOVA followed by Tukey's post hoc analysis. Kruskal-Wallis test followed by Dunn's multiple comparison tests was used for the analysis of non-normally distributed data. RESULTS Repeated LPS challenge led to activation and proliferation of retinal microglia, infiltration of monocyte-derived macrophages into the retina, and breakdown of the blood-retina barrier (BRB) accompanied by accumulation of sub-retinal fluid. Using in vivo imaging, we show that the breakdown of the BRB is highly reproducible but transitory. Acute but not chronic systemic exposure to LPS triggered a robust release of inflammatory mediators in the retina with minimal effects in the blood plasma. Inhibition of the CSF-1R by PLX5622 resulted in depletion of retinal microglia, suppression of cytokine production in the retina, and prevention of BRB breakdown. CONCLUSIONS These findings suggest that microglia/macrophages play an important role in the pathology of retinal disorders characterized by breakdown of the BRB, and suppression of their activation may be a potential therapeutic target for such retinopathies.
Collapse
Affiliation(s)
- Despina Kokona
- Department of Ophthalmology, Inselspital, Bern University Hospital, and University of Bern, CH-3010, Bern, Switzerland.,Department of Clinical Research, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - Andreas Ebneter
- Department of Ophthalmology, Inselspital, Bern University Hospital, and University of Bern, CH-3010, Bern, Switzerland.,Department of Clinical Research, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - Pascal Escher
- Department of Ophthalmology, Inselspital, Bern University Hospital, and University of Bern, CH-3010, Bern, Switzerland.,Department of Clinical Research, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - Martin S Zinkernagel
- Department of Ophthalmology, Inselspital, Bern University Hospital, and University of Bern, CH-3010, Bern, Switzerland. .,Department of Clinical Research, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland.
| |
Collapse
|
12
|
Takeda A, Shinozaki Y, Kashiwagi K, Ohno N, Eto K, Wake H, Nabekura J, Koizumi S. Microglia mediate non-cell-autonomous cell death of retinal ganglion cells. Glia 2018; 66:2366-2384. [PMID: 30375063 DOI: 10.1002/glia.23475] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 05/23/2018] [Accepted: 05/28/2018] [Indexed: 12/22/2022]
Abstract
Excitotoxicity is well known in the neuronal death in the brain and is also linked to neuronal damages in the retina. Recent accumulating evidence show that microglia greatly affect excitotoxicity in the brain, but their roles in retina have received only limited attention. Here, we report that retinal excitotoxicity is mediated by microglia. To this end, we employed three discrete methods, that is, pharmacological inhibition of microglia by minocycline, pharmacological ablation by an antagonist for colony stimulating factor 1 receptor (PLX5622), and genetic ablation of microglia using Iba1-tTA::DTAtetO/tetO mice. Intravitreal injection of NMDA increased the number of apoptotic retinal ganglion cells (RGCs) followed by reduction in the number of RGCs. Although microglia did not respond to NMDA directly, they became reactive earlier than RGC damages. Inhibition or ablation of microglia protected RGCs against NMDA. We found up-regulation of proinflammatory cytokine genes including Il1b, Il6 and Tnfa, among which Tnfa was selectively blocked by minocycline. PLX5622 also suppressed Tnfa expression. Tumor necrosis factor α (TNFα) signals were restricted in microglia at very early followed by spreading into other cell types. TNFα up-regulation in microglia and other cells were significantly attenuated by minocycline and PLX5622, suggesting a central role of microglia for TNFα induction. Both inhibition of TNFα and knockdown of TNF receptor type 1 by siRNA protected RGCs against NMDA. Taken together, our data demonstrate that a phenotypic change of microglia into a neurotoxic one is a critical event for the NMDA-induced degeneration of RGCs, suggesting an importance of non-cell-autonomous mechanism in the retinal neuronal excitotoxicity.
Collapse
Affiliation(s)
- Akiko Takeda
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kenji Kashiwagi
- Department of Ophthalmology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Nobuhiko Ohno
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences (NIPS), Aichi, Japan.,Department of Anatomy, Jichi Medical University, Tochigi, Japan
| | - Kei Eto
- Division of Homeostatic Development, NIPS, Aichi, Japan
| | - Hiroaki Wake
- Division of Homeostatic Development, NIPS, Aichi, Japan.,Division of System Neuroscience, Graduate School of Medicine, Kobe University, Hyogo, Japan.,Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Saitama, Japan
| | | | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| |
Collapse
|
13
|
Kokona D, Jovanovic J, Ebneter A, Zinkernagel MS. In Vivo Imaging of Cx3cr1gfp/gfp Reporter Mice with Spectral-domain Optical Coherence Tomography and Scanning Laser Ophthalmoscopy. J Vis Exp 2017. [PMID: 29155795 DOI: 10.3791/55984] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Spectral domain optical coherence tomography (SD-OCT) and scanning laser ophthalmoscopy (SLO) are extensively used in experimental ophthalmology. In the present protocol, mice expressing green fluorescent protein (gfp) under the promoter of Cx3cr1 (BALB/c-Cx3cr1gfp/gfp) were used to image microglia cells in vivo in the retina. Microglia are resident macrophages of the retina and have been implicated in several retinal diseases1,2,3,4,5,6. This protocol provides a detailed approach for generation of retinal B-scans, with SD-OCT, and imaging of microglia cell distribution in Cx3cr1gfp/gfp mice with SLO in vivo, using an ophthalmic imaging platform system. The protocol can be used in several reporter mouse lines. However, there are some limitations to the protocol presented here. First, both SLO and SD-OCT, when used in the high-resolution mode, collect data with high axial resolution but the lateral resolution is lower (3.5 µm and 6 µm, respectively). Moreover, the focus and saturation level in SLO is highly dependent on parameter selection and correct alignment of the eye. Additionally, using devices designed for human patients in mice is challenging due to the higher total optical power of the mouse eye compared to the human eye; this can lead to lateral magnification inaccuracies7, which are also dependent on the magnification by the mouse lens among others. However, despite that the axial scan position is dependent upon lateral magnification, the axial SD-OCT measurements are accurate8.
Collapse
Affiliation(s)
- Despina Kokona
- Department of Ophthalmology and Department of Clinical Research, Bern University Hospital and University of Bern;
| | - Joël Jovanovic
- Department of Ophthalmology and Department of Clinical Research, Bern University Hospital and University of Bern
| | - Andreas Ebneter
- Department of Ophthalmology and Department of Clinical Research, Bern University Hospital and University of Bern
| | - Martin S Zinkernagel
- Department of Ophthalmology and Department of Clinical Research, Bern University Hospital and University of Bern
| |
Collapse
|