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Hu A, Schmidt MHH, Heinig N. Microglia in retinal angiogenesis and diabetic retinopathy. Angiogenesis 2024:10.1007/s10456-024-09911-1. [PMID: 38564108 DOI: 10.1007/s10456-024-09911-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 02/18/2024] [Indexed: 04/04/2024]
Abstract
Diabetic retinopathy has a high probability of causing visual impairment or blindness throughout the disease progression and is characterized by the growth of new blood vessels in the retina at an advanced, proliferative stage. Microglia are a resident immune population in the central nervous system, known to play a crucial role in regulating retinal angiogenesis in both physiological and pathological conditions, including diabetic retinopathy. Physiologically, they are located close to blood vessels and are essential for forming new blood vessels (neovascularization). In diabetic retinopathy, microglia become widely activated, showing a distinct polarization phenotype that leads to their accumulation around neovascular tufts. These activated microglia induce pathogenic angiogenesis through the secretion of various angiogenic factors and by regulating the status of endothelial cells. Interestingly, some subtypes of microglia simultaneously promote the regression of neovascularization tufts and normal angiogenesis in neovascularization lesions. Modulating the state of microglial activation to ameliorate neovascularization thus appears as a promising potential therapeutic approach for managing diabetic retinopathy.
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Affiliation(s)
- Aiyan Hu
- Institute of Anatomy, Medical Faculty Carl Gustav Carus, Technische Universität Dresden School of Medicine, Fetscherstr 74, 01307, Dresden, Germany
| | - Mirko H H Schmidt
- Institute of Anatomy, Medical Faculty Carl Gustav Carus, Technische Universität Dresden School of Medicine, Fetscherstr 74, 01307, Dresden, Germany.
| | - Nora Heinig
- Institute of Anatomy, Medical Faculty Carl Gustav Carus, Technische Universität Dresden School of Medicine, Fetscherstr 74, 01307, Dresden, Germany.
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2
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Gui SY, Wang XC, Huang ZH, Li MM, Wang JH, Gui SY, Zhang GH, Lu Y, Tao LM, Qian HS, Jiang ZX. Nanoscale coordination polymer Fe-DMY downregulating Poldip2-Nox4-H 2O 2 pathway and alleviating diabetic retinopathy. J Pharm Anal 2023; 13:1326-1345. [PMID: 38174114 PMCID: PMC10759264 DOI: 10.1016/j.jpha.2023.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/06/2023] [Accepted: 05/08/2023] [Indexed: 01/05/2024] Open
Abstract
Diabetic retinopathy (DR) is a prevalent microvascular complication of diabetes and the leading cause of blindness and severe visual impairment in adults. The high levels of glucose trigger multiple intracellular oxidative stress pathways, such as POLDIP2, resulting in excessive reactive oxygen species (ROS) production and increased expression of vascular cell adhesion molecule-1 (VCAM-1), hypoxia-inducible factor 1α (HIF-1α), and vascular endothelial growth factor (VEGF), causing microvascular dysfunction. Dihydromyricetin (DMY) is a natural flavonoid small molecule antioxidant. However, it exhibits poor solubility in physiological environments, has a short half-life in vivo, and has low oral bioavailability. In this study, we present, for the first time, the synthesis of ultra-small Fe-DMY nano-coordinated polymer particles (Fe-DMY NCPs), formed by combining DMY with low-toxicity iron ions. In vitro and in vivo experiments confirm that Fe-DMY NCPs alleviate oxidative stress-induced damage to vascular endothelial cells by high glucose, scavenge excess ROS, and improve pathological features of DR, such as retinal vascular leakage and neovascularization. Mechanistic validation indicates that Fe-DMY NCPs can inhibit the activation of the Poldip2-Nox4-H2O2 signaling pathway and downregulate vital vascular function indicators such as VCAM-1, HIF-1α, and VEGF. These findings suggest that Fe-DMY NCPs could serve as a safe and effective antioxidant and microangio-protective agent, with the potential as a novel multimeric drug for DR therapy.
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Affiliation(s)
- Si-Yu Gui
- Department of Ophthalmology, The Second Affiliated Hospital of Anhui Medical University, Hefei, 230601, China
- Department of Clinical Medicine, The Second School of Clinical Medicine, Anhui Medical University, Hefei, 230032, China
| | - Xin-Chen Wang
- Department of Ophthalmology, The Second Affiliated Hospital of Anhui Medical University, Hefei, 230601, China
- Department of Clinical Medicine, The Second School of Clinical Medicine, Anhui Medical University, Hefei, 230032, China
| | - Zhi-Hao Huang
- Department of Clinical Medicine, The Second School of Clinical Medicine, Anhui Medical University, Hefei, 230032, China
| | - Mei-Mei Li
- Department of Clinical Medicine, The First School of Clinical Medicine, Anhui Medical University, Hefei, 230032, China
| | - Jia-Hao Wang
- Department of Clinical Medicine, The First School of Clinical Medicine, Anhui Medical University, Hefei, 230032, China
| | - Si-Yin Gui
- Department of Laboratory, Fengtai County First People's Hospital, Huainan, Anhui, 232101, China
- Department of Immunology, The School of Medicine, Anhui University of Technology, Huainan, Anhui, 232100, China
| | - Gan-Hua Zhang
- Department of Nursing, The Second Affiliated Hospital of Anhui Medical University, Hefei, 230601, China
| | - Yao Lu
- Department of Anesthesiology, The First Affiliated Hospital of Anhui Medical University, Hefei, 230032, China
| | - Li-Ming Tao
- Department of Ophthalmology, The Second Affiliated Hospital of Anhui Medical University, Hefei, 230601, China
| | - Hai-Sheng Qian
- School of Biomedical Engineering, Research and Engineering Center of Biomedical Materials, Anhui Medical University, Hefei, 230032, China
| | - Zheng-Xuan Jiang
- Department of Ophthalmology, The Second Affiliated Hospital of Anhui Medical University, Hefei, 230601, China
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Ong JX, Bou Ghanem GO, Nesper PL, Moonjely J, Fawzi AA. Optical Coherence Tomography Angiography of Volumetric Arteriovenous Relationships in the Healthy Macula and Their Derangement in Disease. Invest Ophthalmol Vis Sci 2023; 64:6. [PMID: 37133834 PMCID: PMC10166119 DOI: 10.1167/iovs.64.5.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 04/09/2023] [Indexed: 05/04/2023] Open
Abstract
Purpose To characterize relative arteriovenous connectivity of the healthy macula imaged by optical coherence tomography angiography (OCTA) using a new volumetric tool. Methods OCTA volumes were obtained for 20 healthy controls (20 eyes). Two graders identified superficial arterioles and venules. We implemented a custom watershed algorithm to identify capillaries most closely connected to arterioles and venules by using the large vessels as seeds to flood the vascular network. We calculated ratios of arteriolar- to venular-connected capillaries (A/V ratios) and adjusted flow indices (AFIs) for superficial capillary plexuses (SCPs), middle capillary plexuses (MCPs), and deep capillary plexuses (DCPs). We also analyzed two eyes with proliferative diabetic retinopathy (PDR) and one eye with macular telangiectasia (MacTel) to evaluate the utility of this method in visualizing pathological vascular connectivity. Results In healthy eyes, the MCP showed a greater proportion of arteriolar-connected vessels than the SCP and DCP (all P < 0.001). In the SCP, the arteriolar-connected AFI exceeded the venular-connected AFI, but this pattern reversed in the MCP and DCP, with higher venular-connected AFI (all P < 0.001). In PDR eyes, preretinal neovascularization originated from venules, whereas intraretinal microvascular abnormalities were heterogeneous, with some originating from venules and others representing dilated MCP capillary loops. In MacTel, diving SCP venules formed the epicenter of the outer retinal anomalous vascular network. Conclusions Healthy eyes showed a higher MCP A/V ratio but relatively slower arteriolar vs. venular flow velocity in the MCP and DCP, which may explain deep retinal vulnerability to ischemia. In eyes with complex vascular pathology, our connectivity findings were consistent with histopathologic studies.
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Affiliation(s)
- Janice X Ong
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Ghazi O Bou Ghanem
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Peter L Nesper
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Jessica Moonjely
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Amani A Fawzi
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
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Braunger BM, Gießl A, Schlötzer-Schrehardt U. The Blood-ocular Barriers and their Dysfunction: Anatomy, Physiology, Pathology. Klin Monbl Augenheilkd 2023; 240:650-661. [PMID: 37207638 DOI: 10.1055/a-2063-8957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Complex barriers comprise the blood-aqueous (BAB) and the blood-retinal barrier (BRB), and separate anterior and posterior eye chambers, vitreous body, and sensory retina from the circulation. They prevent pathogens and toxins from entering the eye, control movement of fluid, proteins, and metabolites, and contribute to the maintenance of the ocular immune status. Morphological correlates of blood-ocular barriers are tight junctions between neighboring endothelial and epithelial cells, which function as gatekeepers of the paracellular transport of molecules, thereby limiting their uncontrolled access to ocular chambers and tissues. The BAB is composed of tight junctions between endothelial cells of the iris vasculature, endothelial cells of Schlemm's canal inner wall, and cells of the nonpigmented ciliary epithelium. The BRB consists of tight junctions between endothelial cells of the retinal vessels (inner BRB) and epithelial cells of the retinal pigment epithelium (outer BRB). These junctional complexes respond rapidly to pathophysiological changes, thus enabling vascular leakage of blood-derived molecules and inflammatory cells into ocular tissues and chambers. Blood-ocular barrier function, which can be clinically measured by laser flare photometry or fluorophotometry, is compromised in traumatic, inflammatory, or infectious processes, but also frequently contributes to the pathophysiology of chronic diseases of the anterior eye segment and the retina, as exemplified by diabetic retinopathy and age-related macular degeneration.
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Affiliation(s)
- Barbara M Braunger
- Institut für Anatomie und Zellbiologie, Julius-Maximilians-Universität Würzburg, Medizinische Fakultät, Deutschland
| | - Andreas Gießl
- Augenklinik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Medizinische Fakultät, Erlangen, Deutschland
| | - Ursula Schlötzer-Schrehardt
- Augenklinik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Medizinische Fakultät, Erlangen, Deutschland
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Jin Z, Guo Q, Wang Z, Wu X, Hu W, Li J, Li H, Zhu S, Zhang H, Chen Z, Xu H, Shi L, Yang L, Wang Y. Andrographolide suppresses hypoxia-induced embryonic hyaloid vascular system development through HIF-1a/VEGFR2 signaling pathway. Front Cardiovasc Med 2023; 10:1090938. [PMID: 36844722 PMCID: PMC9944699 DOI: 10.3389/fcvm.2023.1090938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 01/04/2023] [Indexed: 02/11/2023] Open
Abstract
Introduction Ocular abnormalities and the development of retinal vasculature may cause postnatal retinopathy. In the past decade, tremendous progress has been made in identifying the mechanisms that regulate retina vasculature. However, the means of regulating embryonic hyaloid vasculature development is largely unknown. This study aims to determine whether and how andrographolide regulates embryonic hyaloid vasculature development. Methods Murine embryonic retinas were used in this study. Whole mount isolectin B4 (IB4) staining, hematoxylin and eosin (H&E) staining, immunohistochemistry (IHC), and immunofluorescence staining (IF) were performed to determine whether andrographolide is critical for embryonic hyaloid vasculature development. BrdU incorporation assay, Boyden chamber migration assay, spheroid sprouting assay, and Matrigel-based tube formation assay were performed to evaluate whether andrographolide regulates the proliferation and migration of vascular endothelial cells. Molecular docking simulation and Co-immunoprecipitation assay were used to observe protein interaction. Results Hypoxia conditions exist in murine embryonic retinas. Hypoxia induces HIF-1a expression; high-expressed HIF-1a interacts with VEGFR2, resulting in the activation of the VEGF signaling pathway. Andrographolide suppresses hypoxia-induced HIF-1a expression and, at least in part, interrupts the interaction between HIF-1a and VEGFR2, causing inhibiting endothelial proliferation and migration, eventually inhibiting embryonic hyaloid vasculature development. Conclusion Our data demonstrated that andrographolide plays a critical role in regulating embryonic hyaloid vasculature development.
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Affiliation(s)
- Zhong Jin
- College of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Qiru Guo
- College of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Zheng Wang
- College of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xiao Wu
- College of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Wangming Hu
- College of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Jiali Li
- College of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Hongfei Li
- College of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Song Zhu
- Chengdu University of Traditional Chinese Medicine, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Haidi Zhang
- Chengdu University of Traditional Chinese Medicine, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Zixian Chen
- School of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Huan Xu
- College of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Liangqin Shi
- College of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Lan Yang
- College of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yong Wang
- College of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China,*Correspondence: Yong Wang, ✉ ; ✉
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Fu X, Feng S, Qin H, Yan L, Zheng C, Yao K. Microglia: The breakthrough to treat neovascularization and repair blood-retinal barrier in retinopathy. Front Mol Neurosci 2023; 16:1100254. [PMID: 36756614 PMCID: PMC9899825 DOI: 10.3389/fnmol.2023.1100254] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 01/03/2023] [Indexed: 01/24/2023] Open
Abstract
Microglia are the primary resident retinal macrophages that monitor neuronal activity in real-time and facilitate angiogenesis during retinal development. In certain retinal diseases, the activated microglia promote retinal angiogenesis in hypoxia stress through neurovascular coupling and guide neovascularization to avascular areas (e.g., the outer nuclear layer and macula lutea). Furthermore, continuously activated microglia secrete inflammatory factors and expedite the loss of the blood-retinal barrier which causes irreversible damage to the secondary death of neurons. In this review, we support microglia can be a potential cellular therapeutic target in retinopathy. We briefly describe the relevance of microglia to the retinal vasculature and blood-retinal barrier. Then we discuss the signaling pathway related to how microglia move to their destinations and regulate vascular regeneration. We summarize the properties of microglia in different retinal disease models and propose that reducing the number of pro-inflammatory microglial death and conversing microglial phenotypes from pro-inflammatory to anti-inflammatory are feasible for treating retinal neovascularization and the damaged blood-retinal barrier (BRB). Finally, we suppose that the unique properties of microglia may aid in the vascularization of retinal organoids.
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Affiliation(s)
- Xuefei Fu
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
| | - Shuyu Feng
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
| | - Huan Qin
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
| | - Lin Yan
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
| | - Caiyan Zheng
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
| | - Kai Yao
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China,College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China,Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Wuhan University of Science and Technology, Wuhan, China,*Correspondence: Kai Yao,
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Bai Q, Wang X, Yan H, Wen L, Zhou Z, Ye Y, Jing Y, Niu Y, Wang L, Zhang Z, Su J, Chang T, Dou G, Wang Y, Sun J. Microglia-Derived Spp1 Promotes Pathological Retinal Neovascularization via Activating Endothelial Kit/Akt/mTOR Signaling. J Pers Med 2023; 13:jpm13010146. [PMID: 36675807 PMCID: PMC9866717 DOI: 10.3390/jpm13010146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/31/2022] [Accepted: 01/03/2023] [Indexed: 01/14/2023] Open
Abstract
Pathological retinal neovascularization (RNV) is the main character of ischemic ocular diseases, which causes severe visual impairments. Though retinal microglia are well acknowledged to play important roles in both physiological and pathological angiogenesis, the molecular mechanisms by which microglia communicates with endothelial cells (EC) remain unknown. In this study, using single-cell RNA sequencing, we revealed that the pro-inflammatory secreted protein Spp1 was the most upregulated gene in microglia in the mouse model of oxygen-induced retinopathy (OIR). Bioinformatic analysis showed that the expression of Spp1 in microglia was respectively regulated via nuclear factor-kappa B (NF-κB) and hypoxia-inducible factor 1α (HIF-1α) pathways, which was further confirmed through in vitro assays using BV2 microglia cell line. To mimic microglia-EC communication, the bEnd.3 endothelial cell line was cultured with conditional medium (CM) from BV2. We found that adding recombinant Spp1 to bEnd.3 as well as treating with hypoxic BV2 CM significantly enhanced EC proliferation and migration, while Spp1 neutralizing blocked those CM-induced effects. Moreover, RNA sequencing of BV2 CM-treated bEnd.3 revealed a significant downregulation of Kit, one of the type III tyrosine kinase receptors that plays a critical role in cell growth and activation. We further revealed that Spp1 increased phosphorylation and expression level of Akt/mTOR signaling cascade, which might account for its pro-angiogenic effects. Finally, we showed that intravitreal injection of Spp1 neutralizing antibody attenuated pathological RNV and improved visual function. Taken together, our work suggests that Spp1 mediates microglia-EC communication in RNV via activating endothelial Kit/Akt/mTOR signaling and is a potential target to treat ischemic ocular diseases.
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Affiliation(s)
- Qian Bai
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
- 63750 Army Hospital of Chinese PLA, Xi’an 710043, China
| | - Xin Wang
- Lintong Rehabilitation Center of PLA Joint Logistics Support Force, Xi’an 710600, China
| | - Hongxiang Yan
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
| | - Lishi Wen
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
| | - Ziyi Zhou
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
| | - Yating Ye
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
- College of Life Science, Northwestern University, Xi’an 710069, China
| | - Yutong Jing
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
| | - Yali Niu
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
| | - Liang Wang
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
- Department of Ophthalmology, The Northern Theater Air Force Hospital, Shenyang 110041, China
| | - Zifeng Zhang
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
| | - Jingbo Su
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
| | - Tianfang Chang
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
| | - Guorui Dou
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
| | - Yusheng Wang
- Eye Institute of Chinese PLA, Fourth Military Medical University, Xi’an 710032, China
- Correspondence: (Y.W.); (J.S.); Tel.: +029-84775371 (Y.W.); +029-84771273 (J.S.)
| | - Jiaxing Sun
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi’an 710032, China
- Correspondence: (Y.W.); (J.S.); Tel.: +029-84775371 (Y.W.); +029-84771273 (J.S.)
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Usui‐Ouchi A, Eade K, Giles S, Ideguchi Y, Ouchi Y, Aguilar E, Wei G, Marra KV, Berlow RB, Friedlander M. Deletion of Tgfβ signal in activated microglia prolongs hypoxia-induced retinal neovascularization enhancing Igf1 expression and retinal leukostasis. Glia 2022; 70:1762-1776. [PMID: 35611927 PMCID: PMC9540888 DOI: 10.1002/glia.24218] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 05/05/2022] [Accepted: 05/05/2022] [Indexed: 12/20/2022]
Abstract
Retinal neovascularization (NV) is the major cause of severe visual impairment in patients with ischemic eye diseases. While it is known that retinal microglia contribute to both physiological and pathological angiogenesis, the molecular mechanisms by which these glia regulate pathological NV have not been fully elucidated. In this study, we utilized a retinal microglia-specific Transforming Growth Factor-β (Tgfβ) receptor knock out mouse model and human iPSC-derived microglia to examine the role of Tgfβ signaling in activated microglia during retinal NV. Using a tamoxifen-inducible, microglia-specific Tgfβ receptor type 2 (Tgfβr2) knockout mouse [Tgfβr2 KO (ΔMG)] we show that Tgfβ signaling in microglia actively represses leukostasis in retinal vessels. Furthermore, we show that Tgfβ signaling represses expression of the pro-angiogenic factor, Insulin-like growth factor 1 (Igf1), independent of Vegf regulation. Using the mouse model of oxygen-induced retinopathy (OIR) we show that Tgfβ signaling in activated microglia plays a role in hypoxia-induced NV where a loss in Tgfβ signaling microglia exacerbates and prolongs retinal NV in OIR. Using human iPSC-derived microglia cells in an in vitro assay, we validate the role of Transforming Growth Factor-β1 (Tgfβ1) in regulating Igf1 expression in hypoxic conditions. Finally, we show that Tgfβ signaling in microglia is essential for microglial homeostasis and that the disruption of Tgfβ signaling in microglia exacerbates retinal NV in OIR by promoting leukostasis and Igf1 expression.
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Affiliation(s)
- Ayumi Usui‐Ouchi
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaCaliforniaUSA
- Department of OphthalmologyJuntendo University Urayasu HospitalChibaJapan
| | - Kevin Eade
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaCaliforniaUSA
- The Lowy Medical Research InstituteLa JollaCaliforniaUSA
| | - Sarah Giles
- The Lowy Medical Research InstituteLa JollaCaliforniaUSA
| | - Yoichiro Ideguchi
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaCaliforniaUSA
| | - Yasuo Ouchi
- Gene Expression LaboratorySalk Institute for Biological StudiesLa JollaCaliforniaUSA
- Department of Regenerative MedicineChiba University Graduate School of MedicineChibaJapan
| | - Edith Aguilar
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaCaliforniaUSA
| | - Guoqin Wei
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaCaliforniaUSA
| | - Kyle V. Marra
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaCaliforniaUSA
- Department of BioengineeringUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Rebecca B. Berlow
- Department of Integrative Structural and Computational BiologyThe Scripps Research InstituteLa JollaCaliforniaUSA
| | - Martin Friedlander
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaCaliforniaUSA
- The Lowy Medical Research InstituteLa JollaCaliforniaUSA
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Fan W, Huang W, Chen J, Li N, Mao L, Hou S. Retinal microglia: Functions and diseases. Immunology 2022; 166:268-286. [PMID: 35403700 DOI: 10.1111/imm.13479] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 01/26/2022] [Accepted: 02/22/2022] [Indexed: 11/29/2022] Open
Affiliation(s)
- Wei Fan
- The First Affiliated Hospital of Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Ophthalmology Chongqing China
- Chongqing Eye Institute Chongqing China
- Chongqing Branch of National Clinical Research Center for Ocular Diseases Chongqing China
| | - Weidi Huang
- The First Affiliated Hospital of Chongqing Medical University Chongqing China
- Department of Ophthalmology, Second Xiangya Hospital Central South University Changsha Hunan China
| | - Jiayi Chen
- The First Affiliated Hospital of Chongqing Medical University Chongqing China
| | - Na Li
- College of Basic Medicine Chongqing Medical University Chongqing China
| | - Liming Mao
- Department of Immunology School of Medicine, Nantong University, 19 Qixiu Road Nantong Jiangsu China
| | - Shengping Hou
- The First Affiliated Hospital of Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Ophthalmology Chongqing China
- Chongqing Eye Institute Chongqing China
- Chongqing Branch of National Clinical Research Center for Ocular Diseases Chongqing China
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Schlecht A, Wolf J, Boneva S, Prinz G, Braunger BM, Wieghofer P, Agostini H, Schlunck G, Lange C. Transcriptional and Distributional Profiling of Microglia in Retinal Angiomatous Proliferation. Int J Mol Sci 2022; 23:3443. [PMID: 35408803 DOI: 10.3390/ijms23073443] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 12/20/2022] Open
Abstract
Macular neovascularization type 3, formerly known as retinal angiomatous proliferation (RAP), is a hallmark of age-related macular degeneration and is associated with an accumulation of myeloid cells, such as microglia (MG) and infiltrating blood-derived macrophages (MAC). However, the contribution of MG and MAC to the myeloid cell pool at RAP sites and their exact functions remain unknown. In this study, we combined a microglia-specific reporter mouse line with a mouse model for RAP to identify the contribution of MG and MAC to myeloid cell accumulation at RAP and determined the transcriptional profile of MG using RNA sequencing. We found that MG are the most abundant myeloid cell population around RAP, whereas MAC are rarely, if ever, associated with late stages of RAP. RNA sequencing of RAP-associated MG showed that differentially expressed genes mainly contribute to immune-associated processes, including chemotaxis and migration in early RAP and proliferative capacity in late RAP, which was confirmed by immunohistochemistry. Interestingly, MG upregulated only a few angiomodulatory factors, suggesting a rather low angiogenic potential. In summary, we showed that MG are the dominant myeloid cell population at RAP sites. Moreover, MG significantly altered their transcriptional profile during RAP formation, activating immune-associated processes and exhibiting enhanced proliferation, however, without showing substantial upregulation of angiomodulatory factors.
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Pauleikhoff D, Pauleikhoff L, Chew EY. Imaging endpoints for clinical trials in MacTel type 2. Eye (Lond) 2022; 36:284-93. [PMID: 34389818 DOI: 10.1038/s41433-021-01723-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/15/2021] [Accepted: 07/26/2021] [Indexed: 02/03/2023] Open
Abstract
INTRODUCTION Macular Telangiectasia type 2 (MacTel) is a bilateral neurodegenerative disease associated with dysfunction in the serine and lipid metabolism resulting in loss of Muller cells and photoreceptors. Typical structural changes include vascular abnormalities, loss of retinal transparency, redistribution of macular pigment and thinning of the central retina with photoreceptor loss. The presence and extent of photoreceptor loss, as visible on Optical Coherence Tomography (OCT) ("disease severity scale"), correlate with functional loss and the limitation of photoreceptor loss appears to be the most promising therapeutic approach. Ongoing clinical trials of ciliary neurotrophic factor (CNTF) implants for the treatment of MacTel are using this outcome to evaluate efficacy. An ideal outcome measure provides the ability to quantify the extent of the disease progression with precision and reproducibility. METHODS This review describes the changes and findings on different imaging techniques including fluorescein- and OCT angiography, blue light reflectance, 1- and 2-wavelength autofluorescence and OCT. RESULTS The possibilities of objective quantification of the severity of MacTel and correlation with functional characteristics such as best-corrected visual acuity (BCVA) and microperimetry and their applications as quantitative imaging endpoints for clinical treatment trials are discussed. OCT and especially en face OCT could be demonstrated as precise and reproducible methods to quantify the area of photoreceptor loss, which correlated highly significantly with functional loss in microperimetry. CONCLUSION The analysis of the area of photoreceptor loss on en face OCT is the most reliable imaging endpoint for treatment trials in MacTel. This method is already being used in ongoing randomized trials.
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Jin N, Sha W, Gao L. Shaping the Microglia in Retinal Degenerative Diseases Using Stem Cell Therapy: Practice and Prospects. Front Cell Dev Biol 2021; 9:741368. [PMID: 34966736 PMCID: PMC8710684 DOI: 10.3389/fcell.2021.741368] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 11/29/2021] [Indexed: 12/11/2022] Open
Abstract
Retinal degenerative disease (RDD) refers to a group of diseases with retinal degeneration that cause vision loss and affect people's daily lives. Various therapies have been proposed, among which stem cell therapy (SCT) holds great promise for the treatment of RDDs. Microglia are immune cells in the retina that have two activation phenotypes, namely, pro-inflammatory M1 and anti-inflammatory M2 phenotypes. These cells play an important role in the pathological progression of RDDs, especially in terms of retinal inflammation. Recent studies have extensively investigated the therapeutic potential of stem cell therapy in treating RDDs, including the immunomodulatory effects targeting microglia. In this review, we substantially summarized the characteristics of RDDs and microglia, discussed the microglial changes and phenotypic transformation of M1 microglia to M2 microglia after SCT, and proposed future directions for SCT in treating RDDs.
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Affiliation(s)
- Ni Jin
- Senior Department of Ophthalmology, The Third Medical Center of Chinese People's Liberation Army General Hospital, Beijing, China.,Department of Endocrinology, The Second Medical Center and National Clinical Research Center for Geriatric Diseases, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Weiwei Sha
- Department of Endocrinology, The Second Medical Center and National Clinical Research Center for Geriatric Diseases, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Lixiong Gao
- Senior Department of Ophthalmology, The Third Medical Center of Chinese People's Liberation Army General Hospital, Beijing, China
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13
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Qiang W, Wei R, Chen Y, Chen D. Clinical Pathological Features and Current Animal Models of Type 3 Macular Neovascularization. Front Neurosci 2021; 15:734860. [PMID: 34512255 PMCID: PMC8427186 DOI: 10.3389/fnins.2021.734860] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 07/29/2021] [Indexed: 02/05/2023] Open
Abstract
Type 3 macular neovascularization (MNV3), or retinal angiomatous proliferation (RAP), is a distinct type of neovascular age-related macular degeneration (AMD), which is a leading cause of vision loss in older persons. During the past decade, systematic investigation into the clinical, multimodal imaging, and histopathological features and therapeutic outcomes has provided important new insight into this disease. These studies favor the retinal origin of MNV3 and suggest the involvement of retinal hypoxia, inflammation, von Hippel–Lindau (VHL)–hypoxia-inducible factor (HIF)–vascular endothelial growth factor (VEGF) pathway, and multiple cell types in the development and progression of MNV3. Several mouse models, including the recently built Rb/p107/Vhl triple knockout mouse model by our group, have induced many of the histological features of MNV3 and provided much insight into the underlying pathological mechanisms. These models have revealed the roles of retinal hypoxia, inflammation, lipid metabolism, VHL/HIF pathway, and retinoblastoma tumor suppressor (Rb)–E2F cell cycle pathway in the development of MNV3. This article will summarize the clinical, multimodal imaging, and pathological features of MNV3 and the diversity of animal models that exist for MNV3, as well as their strengths and limitations.
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Affiliation(s)
- Wei Qiang
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.,Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Ran Wei
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.,Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Yongjiang Chen
- The School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada
| | - Danian Chen
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.,Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
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Schlecht A, Zhang P, Wolf J, Thien A, Rosmus DD, Boneva S, Schlunck G, Lange C, Wieghofer P. Secreted Phosphoprotein 1 Expression in Retinal Mononuclear Phagocytes Links Murine to Human Choroidal Neovascularization. Front Cell Dev Biol 2021; 8:618598. [PMID: 33585455 PMCID: PMC7876283 DOI: 10.3389/fcell.2020.618598] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 12/01/2020] [Indexed: 01/08/2023] Open
Abstract
Age-related macular degeneration (AMD) represents the most common cause of blindness in the elderly in the Western world. An impairment of the outer blood-retina barrier and a localized inflammatory microenvironment cause sprouting of choroidal neovascular membranes (CNV) in neovascular AMD that are in intimate contact with surrounding myeloid cells, such as retinal microglia, and ultimately lead to visual impairment. The discovery of novel target molecules to interfere with angiogenesis and inflammation is vital for future treatment approaches in AMD patients. To explore the transcriptional profile and the function of retinal microglia at sites of CNV, we performed a comprehensive RNA-seq analysis of retinal microglia in the mouse model of laser-induced choroidal neovascularization (mCNV). Here, we identified the angiogenic factor Osteopontin (Opn), also known as "secreted phosphoprotein 1" (Spp1), as one of the most highly expressed genes in retinal microglia in the course of CNV formation. We confirmed the presence of SPP1 at the lesion site in recruited retinal microglia in Cx3cr1 CreER:Rosa26-tdTomato reporter mice by confocal microscopy and in whole retinal tissue lysates by ELISA highlighting a massive local production of SPP1. Inhibition of SPP1 by intravitreal injection of an anti-SPP1 antibody significantly increased the lesion size compared to IgG-treated control eyes. In line with our results in rodents, we found an increased SPP1 mRNA expression in surgically extracted human choroidal neovascular (hCNV) membranes by the quantitative RNA-seq approach of massive analysis of cDNA ends (MACE). Numerous IBA1+SPP1+ myeloid cells were detected in human CNV membranes. Taken together, these results highlight the importance of SPP1 in the formation of CNV and potentially offer new opportunities for therapeutic intervention by modulating the SPP1 pathway.
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Affiliation(s)
- Anja Schlecht
- Eye Center, Medical Center, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Peipei Zhang
- Eye Center, Medical Center, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Julian Wolf
- Eye Center, Medical Center, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Adrian Thien
- Eye Center, Medical Center, Medical Faculty, University of Freiburg, Freiburg, Germany
| | | | - Stefaniya Boneva
- Eye Center, Medical Center, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Günther Schlunck
- Eye Center, Medical Center, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Clemens Lange
- Eye Center, Medical Center, Medical Faculty, University of Freiburg, Freiburg, Germany
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Mueller S, Gunnemann F, Rothaus K, Book M, Faatz H, Bird A, Pauleikhoff D. Incidence and phenotypical variation of outer retina-associated hyperreflectivity in macular telangiectasia type 2. Br J Ophthalmol 2021; 105:573-576. [PMID: 33414243 DOI: 10.1136/bjophthalmol-2020-317997] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/23/2020] [Accepted: 12/16/2020] [Indexed: 11/04/2022]
Abstract
BACKGROUND Macular telangiectasia type 2 (MacTel) is a neurodegenerative disease resulting in photoreceptor loss. Optical coherence tomography (OCT) reveals outer retina-associated hyperreflectivity (ORaH) as part of this process. The purpose of this study was to describe the incidence and phenotypical variation of ORaH. METHODS Different parameters of ORaH were analysed: OCT characteristics (Spectralis SD-OCT), correlation with vascular changes (OCT angiography; OCTA 3×3 mm Optovue) and correlation with hyperpigmentation (autofluorescence/fundus images). ORaH was also evaluated regarding the grade of severity of photoreceptor loss (Disease Severity Scale). RESULTS Of 220 eyes with MacTel type 2, 106 demonstrated ORaH. On OCT, the size, the extension into the inner retina and the contact with retinal pigment epithelium (RPE) of the ORaH were variable. On OCTA neovascularisation (NV) in the outer retina (OR) was present at the location of the ORaH in 97.6%. Increasing size of NV correlated with progressive photoreceptor loss. In 86.6% with NV, the flow signals were visible between the OR and the choriocapillaris. In 85.7%, the ORaH was associated with hyperpigmentation on autofluorescence and fundus colour images. CONCLUSIONS The presence of ORaH is associated with increasing photoreceptor loss and disease severity. In these more advanced cases of the present study, a variable presentation of ORaH in respect to size and form was seen, but in most cases, ORaH was in contact to the RPE. Additionally, ORaH was associated with hyperpigmentation and OR NV on OCTA. These results are consistent with the concept of ORaH representing fibrovascular OR-NV with RPE proliferation after contact with the RPE.
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Affiliation(s)
- Stefanie Mueller
- Department of Ophthalmology, St. Franziskus Hospital, Münster, Germany
| | - Frederic Gunnemann
- Department of Ophthalmology, St. Franziskus Hospital, Münster, Germany.,Retinal Disorders and Ophthalmic Genetics, Jules Stein Eye Institute, Los Angeles, California, USA
| | - Kai Rothaus
- Department of Ophthalmology, St. Franziskus Hospital, Münster, Germany
| | - Marius Book
- Department of Ophthalmology, St. Franziskus Hospital, Münster, Germany
| | - Henrik Faatz
- Department of Ophthalmology, St. Franziskus Hospital, Münster, Germany
| | - Alan Bird
- Genetics, Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Daniel Pauleikhoff
- Department of Ophthalmology, St. Franziskus Hospital, Münster, Germany .,Department of Ophthalmology, University of Duisburg-Essen Faculty of Medicine, Essen, Nordrhein-Westfalen, Germany
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Abstract
Diabetic retinopathy is a vision-threatening disease affecting neurons and microvasculature of the retina. The development of this disease is associated with the action of inflammatory factors that are connected to the activation of microglial cells, the resident tissue macrophages of the CNS. In the quiescent state, microglial cells help maintain tissue homeostasis in the retina through phagocytosis and control of low-grade inflammation. However, prolonged tissue stress due to hyperglycemia primes microglia to become overly reactive with the concomitant production of pro-inflammatory cytokines and chemokines causing chronic inflammation. In this review, we provide evidence of microglial cell activation and pro-inflammatory molecules associated with the development and progression of diabetic retinopathy. We further highlight innovative animal models that can mimic the disease in humans and discuss strategies in modulating microglial-mediated inflammation as potential therapeutic approaches in managing the disease.
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Affiliation(s)
- Urbanus Muthai Kinuthia
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.,Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | - Anne Wolf
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.,Center for Molecular Medicine, University of Cologne, Cologne, Germany
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