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Hu A, Schmidt MHH, Heinig N. Microglia in retinal angiogenesis and diabetic retinopathy. Angiogenesis 2024; 27:311-331. [PMID: 38564108 PMCID: PMC11303477 DOI: 10.1007/s10456-024-09911-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [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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Hu G, Gu L, Wang R, Jian Q, Lv K, Xia M, Lai M, Shen T, Hu J, Yang S, Ye C, Zhang X, Wang Y, Xu X, Zhang F. Ethanolamine as a biomarker and biomarker-based therapy for diabetic retinopathy in glucose-well-controlled diabetic patients. Sci Bull (Beijing) 2024; 69:1920-1935. [PMID: 38423871 DOI: 10.1016/j.scib.2023.12.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/21/2023] [Accepted: 12/29/2023] [Indexed: 03/02/2024]
Abstract
Diabetic retinopathy (DR) is the leading cause of blindness among the working-age population. Although controlling blood glucose levels effectively reduces the incidence and development of DR to less than 50%, there are currently no diagnostic biomarkers or effective treatments for DR development in glucose-well-controlled diabetic patients (GW-DR). In this study, we established a prospective GW-DR cohort by strictly adhering to glycemic control guidelines and maintaining regular retinal examinations over a median 2-year follow-up period. The discovery cohort encompassed 71 individuals selected from a pool of 292 recruited diabetic patients at baseline, all of whom consistently maintained hemoglobin A1c (HbA1c) levels below 7% without experiencing hypoglycemia. Within this cohort of 71 individuals, 21 subsequently experienced new-onset GW-DR, resulting in an incidence rate of 29.6%. In the validation cohort, we also observed a significant GW-DR incidence rate of 17.9%. Employing targeted metabolomics, we investigated the metabolic characteristics of serum in GW-DR, revealing a significant association between lower levels of ethanolamine and GW-DR risk. This association was corroborated in the validation cohort, exhibiting superior diagnostic performance in distinguishing GW-DR from diabetes compared to the conventional risk factor HbA1c, with AUCs of 0.954 versus 0.506 and 0.906 versus 0.521 in the discovery and validation cohorts, respectively. Furthermore, in a streptozotocin (STZ)-induced diabetic rat model, ethanolamine attenuated diabetic retinal inflammation, accompanied by suppression of microglial diacylglycerol (DAG)-dependent protein kinase C (PKC) pathway activation. In conclusion, we propose that ethanolamine is a potential biomarker and represents a viable biomarker-based therapeutic option for GW-DR.
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Affiliation(s)
- Guangyi Hu
- National Clinical Research Center for Eye Diseases, Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; Eye Institute of Shanghai Jiao Tong University School, Shanghai 200080, China; Shanghai Key Laboratory of Fundus Diseases, Shanghai 200080, China; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai 200080, China
| | - Liping Gu
- Department of Endocrinology and Metabolism, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Ruonan Wang
- National Clinical Research Center for Eye Diseases, Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; Eye Institute of Shanghai Jiao Tong University School, Shanghai 200080, China; Shanghai Key Laboratory of Fundus Diseases, Shanghai 200080, China; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai 200080, China
| | - Qizhi Jian
- National Clinical Research Center for Eye Diseases, Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; Eye Institute of Shanghai Jiao Tong University School, Shanghai 200080, China; Shanghai Key Laboratory of Fundus Diseases, Shanghai 200080, China; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai 200080, China
| | - Kangjia Lv
- National Clinical Research Center for Eye Diseases, Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; Eye Institute of Shanghai Jiao Tong University School, Shanghai 200080, China; Shanghai Key Laboratory of Fundus Diseases, Shanghai 200080, China; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai 200080, China
| | - Mengxue Xia
- National Clinical Research Center for Eye Diseases, Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; Eye Institute of Shanghai Jiao Tong University School, Shanghai 200080, China; Shanghai Key Laboratory of Fundus Diseases, Shanghai 200080, China; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai 200080, China
| | - Mengyu Lai
- Department of Endocrinology and Metabolism, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Tingting Shen
- Department of Endocrinology and Metabolism, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Jing Hu
- National Clinical Research Center for Eye Diseases, Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; Eye Institute of Shanghai Jiao Tong University School, Shanghai 200080, China; Shanghai Key Laboratory of Fundus Diseases, Shanghai 200080, China; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai 200080, China
| | - Sen Yang
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China; Kidney Disease Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Cunqi Ye
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China; Kidney Disease Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Xiaonan Zhang
- National Clinical Research Center for Eye Diseases, Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Yufan Wang
- Department of Endocrinology and Metabolism, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China.
| | - Xun Xu
- National Clinical Research Center for Eye Diseases, Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; Eye Institute of Shanghai Jiao Tong University School, Shanghai 200080, China; Shanghai Key Laboratory of Fundus Diseases, Shanghai 200080, China; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai 200080, China.
| | - Fang Zhang
- National Clinical Research Center for Eye Diseases, Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; Department of Endocrinology and Metabolism, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; Eye Institute of Shanghai Jiao Tong University School, Shanghai 200080, China; Shanghai Key Laboratory of Fundus Diseases, Shanghai 200080, China; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai 200080, China.
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3
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Pan C, Zhang Y, Yan J, Zhou Y, Wang S, Liu X, Zhang P, Yang H. Extreme environments and human health: From the immune microenvironments to immune cells. ENVIRONMENTAL RESEARCH 2023; 236:116800. [PMID: 37527745 DOI: 10.1016/j.envres.2023.116800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 07/20/2023] [Accepted: 07/29/2023] [Indexed: 08/03/2023]
Abstract
Exposure to extreme environments causes specific acute and chronic physiological responses in humans. The adaptation and the physiological processes under extreme environments predominantly affect multiple functional systems of the organism, in particular, the immune system. Dysfunction of the immune system affected by several extreme environments (including hyperbaric environment, hypoxia, blast shock, microgravity, hypergravity, radiation exposure, and magnetic environment) has been observed from clinical macroscopic symptoms to intracorporal immune microenvironments. Therefore, simulated extreme conditions are engineered for verifying the main influenced characteristics and factors in the immune microenvironments. This review summarizes the responses of immune microenvironments to these extreme environments during in vivo or in vitro exposure, and the approaches of engineering simulated extreme environments in recent decades. The related microenvironment engineering, signaling pathways, molecular mechanisms, clinical therapy, and prevention strategies are also discussed.
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Affiliation(s)
- Chengwei Pan
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China; Engineering Research Center of Chinese Ministry of Education for Biological Diagnosis, Treatment and Protection Technology and Equipment, China; Research Center of Special Environmental Biomechanics & Medical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China
| | - Yuzhi Zhang
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China; Engineering Research Center of Chinese Ministry of Education for Biological Diagnosis, Treatment and Protection Technology and Equipment, China; Research Center of Special Environmental Biomechanics & Medical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China
| | - Jinxiao Yan
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China; Engineering Research Center of Chinese Ministry of Education for Biological Diagnosis, Treatment and Protection Technology and Equipment, China; Research Center of Special Environmental Biomechanics & Medical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China
| | - Yidan Zhou
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China; Engineering Research Center of Chinese Ministry of Education for Biological Diagnosis, Treatment and Protection Technology and Equipment, China; Research Center of Special Environmental Biomechanics & Medical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China
| | - Sijie Wang
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China; Engineering Research Center of Chinese Ministry of Education for Biological Diagnosis, Treatment and Protection Technology and Equipment, China; Research Center of Special Environmental Biomechanics & Medical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China
| | - Xiru Liu
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China; Engineering Research Center of Chinese Ministry of Education for Biological Diagnosis, Treatment and Protection Technology and Equipment, China; Research Center of Special Environmental Biomechanics & Medical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China
| | - Pan Zhang
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China; Research Center of Special Environmental Biomechanics & Medical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China; School of Food Science and Engineering, Shaanxi University of Science & Technology, 710021, China.
| | - Hui Yang
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China; Engineering Research Center of Chinese Ministry of Education for Biological Diagnosis, Treatment and Protection Technology and Equipment, China; Research Center of Special Environmental Biomechanics & Medical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China.
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Augustine J, Pavlou S, Harkin K, Stitt AW, Xu H, Chen M. IL-33 regulates Müller cell-mediated retinal inflammation and neurodegeneration in diabetic retinopathy. Dis Model Mech 2023; 16:dmm050174. [PMID: 37671525 PMCID: PMC10499035 DOI: 10.1242/dmm.050174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 07/31/2023] [Indexed: 09/07/2023] Open
Abstract
Diabetic retinopathy (DR) is characterised by dysfunction of the retinal neurovascular unit, leading to visual impairment and blindness. Müller cells are key components of the retinal neurovascular unit and diabetes has a detrimental impact on these glial cells, triggering progressive neurovascular pathology of DR. Amongst many factors expressed by Müller cells, interleukin-33 (IL-33) has an established immunomodulatory role, and we investigated the role of endogenous IL-33 in DR. The expression of IL-33 in Müller cells increased during diabetes. Wild-type and Il33-/- mice developed equivalent levels of hyperglycaemia and weight loss following streptozotocin-induced diabetes. Electroretinogram a- and b-wave amplitudes, neuroretina thickness, and the numbers of cone photoreceptors and ganglion cells were significantly reduced in Il33-/- diabetic mice compared with those in wild-type counterparts. The Il33-/- diabetic retina also exhibited microglial activation, sustained gliosis, and upregulation of pro-inflammatory cytokines and neurotrophins. Primary Müller cells from Il33-/- mice expressed significantly lower levels of neurotransmitter-related genes (Glul and Slc1a3) and neurotrophin genes (Cntf, Lif, Igf1 and Ngf) under high-glucose conditions. Our results suggest that deletion of IL-33 promotes inflammation and neurodegeneration in DR, and that this cytokine is critical for regulation of glutamate metabolism, neurotransmitter recycling and neurotrophin secretion by Müller cells.
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Affiliation(s)
- Josy Augustine
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - Sofia Pavlou
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - Kevin Harkin
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - Alan W. Stitt
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - Heping Xu
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - Mei Chen
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
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5
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Liu C, Cao Q, Chen Y, Chen X, Zhu Y, Zhang Z, Wei W. Rhein protects retinal Müller cells from high glucose-induced injury via activating the AMPK/Sirt1/PGC-1α pathway. J Recept Signal Transduct Res 2023:1-10. [PMID: 37330920 DOI: 10.1080/10799893.2023.2223319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 01/23/2023] [Accepted: 02/07/2023] [Indexed: 06/20/2023]
Abstract
Oxidative stress, inflammation and apoptosis are important pathogenic factors of diabetic retinopathy (DR). In the current study, we aimed to evaluate the potential role of Rhein, a natural anthraquinone compound found in rhubarb, in high glucose (HG)-induced Müller cells (MIO-M1). Cell Counting Kit‑8 assay, TUNEL assay, Western blot analysis, Reverse transcription quantitative polymerase chain reaction (RT-qPCR), and ELISA were conducted to assess the effects of Rhein on Müller cells. Additionally, the EX-527, an Sirt1 inhibitor, was used to study whether the effects of Rhein, on HG-induced Müller cells were mediated by activation of the Sirt1 signaling pathway. Our data showed that Rhein improved cell viability of HG-induced Müller cells. Rhein reduced the ROS and MDA production and increased the activities of SOD and CAT in Müller cells in response to HG stimulation. Rhein decreased the production of VEGF, IL-1β, IL-6 and TNF-α. Moreover, Rhein attenuated HG-induced apoptosis, evidenced by increase in Bcl-2 level and decreases in the Bax, caspase-3 expression. It was also found that EX-527 counteracted Rhein-mediated anti-inflammatory, antioxidant and anti-apoptosis effects on Müller cells. The protein levels of p-AMPK and PGC-1α were also upregulated by Rhein. In conclusion, these findings support that Rhein may ameliorate HG-induced inflammation, oxidative stress, apoptosis and protect against mitochondrial dysfunction by the activation of the AMPK/Sirt1/PGC-1α signaling pathway.
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Affiliation(s)
- Cong Liu
- Department of Ophthalmology, The Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
- Department of Ophthalmology, Jinling Hospital, Nanjing University, School of Medicine, Nanjing, People's Republic of China
| | - Qian Cao
- Department of Ophthalmology, Jinling Hospital, Nanjing University, School of Medicine, Nanjing, People's Republic of China
| | - Yueqin Chen
- Department of Ophthalmology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
| | - Xi Chen
- Department of Ophthalmology, The Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
| | - Yujie Zhu
- Department of Ophthalmology, The Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
| | - Zhonghua Zhang
- Department of Anesthesiology, Jinling Hospital, Nanjing University, School of Medicine, Nanjing, People's Republic of China
| | - Wei Wei
- Department of Ophthalmology, The Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
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Huang T, Fakurazi S, Cheah PS, Ling KH. REST Targets JAK-STAT and HIF-1 Signaling Pathways in Human Down Syndrome Brain and Neural Cells. Int J Mol Sci 2023; 24:9980. [PMID: 37373133 DOI: 10.3390/ijms24129980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/02/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Down syndrome (DS) is the most frequently diagnosed chromosomal disorder of chromosome 21 (HSA21) aneuploidy, characterized by intellectual disability and reduced lifespan. The transcription repressor, Repressor Element-1 Silencing Transcription factor (REST), which acts as an epigenetic regulator, is a crucial regulator of neuronal and glial gene expression. In this study, we identified and investigated the role of REST-target genes in human brain tissues, cerebral organoids, and neural cells in Down syndrome. Gene expression datasets generated from healthy controls and DS samples of human brain tissues, cerebral organoids, NPC, neurons, and astrocytes were retrieved from the Gene Ontology (GEO) and Sequence Read Archive (SRA) databases. Differential expression analysis was performed on all datasets to produce differential expression genes (DEGs) between DS and control groups. REST-targeted DEGs were subjected to functional ontologies, pathways, and network analyses. We found that REST-targeted DEGs in DS were enriched for the JAK-STAT and HIF-1 signaling pathways across multiple distinct brain regions, ages, and neural cell types. We also identified REST-targeted DEGs involved in nervous system development, cell differentiation, fatty acid metabolism and inflammation in the DS brain. Based on the findings, we propose REST as the critical regulator and a promising therapeutic target to modulate homeostatic gene expression in the DS brain.
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Affiliation(s)
- Tan Huang
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
| | - Sharida Fakurazi
- Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
| | - Pike-See Cheah
- Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
| | - King-Hwa Ling
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
- Malaysian Research Institute on Ageing (MyAgeingTM), Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
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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: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [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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Xu H, Chen M. Immune response in retinal degenerative diseases - Time to rethink? Prog Neurobiol 2022; 219:102350. [PMID: 36075351 DOI: 10.1016/j.pneurobio.2022.102350] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 08/24/2022] [Accepted: 09/02/2022] [Indexed: 11/30/2022]
Abstract
Retinal degeneration comprises a group of diseases whereby either the retinal neurons or the neurovascular unit degenerates leading to the loss of visual function. Although the initial cause varies in different conditions, inflammation is known to play an important role in disease pathogenesis. Recent advances in molecular and cell biology and systems biology have yielded unexpected findings, including the heterogeneity of immune cells in the degenerative retina, bidirectional neuron-microglia cross talk, and links to the gut microbiome. Here we discuss the immune response in retinal degenerative conditions, taking into account both regional (retinal) and systemic factors. We propose to classify retinal degeneration into dry and wet forms based on whether the blood-retinal barrier (BRB) is breached and fluid is accumulated in retinal parenchyma. The dry form has a relatively intact BRB and is characterised by progressive retinal thinning. Immune response to degenerative insults is dominated by the retinal defence system, which remains to be regulated by neurons. In contrast, the wet form has retinal oedema due to BRB damaged. Inflammation is executed by infiltrating immune cells as well as the retinal defence system. The gut microbiome will have easy access to the retina in wet retinal degeneration and may affect significantly retinal immune response.
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Affiliation(s)
- Heping Xu
- Aier Institute of Optometry and Vision Science, Changsha 410000, China; The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, BT9 7BL, UK.
| | - Mei Chen
- The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, BT9 7BL, UK.
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Liu Z, Wang Y, Ding Y, Wang H, Zhang J, Wang H. CXCL7 aggravates the pathological manifestations of neuromyelitis optica spectrum disorder by enhancing the inflammatory infiltration of neutrophils, macrophages and microglia. Clin Immunol 2022; 245:109139. [DOI: 10.1016/j.clim.2022.109139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/30/2022] [Accepted: 09/12/2022] [Indexed: 11/03/2022]
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10
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Roles of CSF2 as a modulator of inflammation during retinal degeneration. Cytokine 2022; 158:155996. [PMID: 35988458 DOI: 10.1016/j.cyto.2022.155996] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 07/30/2022] [Accepted: 08/03/2022] [Indexed: 11/20/2022]
Abstract
Colony-stimulating factor 2 (CSF2) is a potent cytokine that stimulates myeloid cells, such as dendritic cells and macrophages. We have been analyzing the roles of microglia in retinal degeneration through the modulation of inflammation in the eye, and examined the roles of CSF2 in this process. Both subunits of the CSF2 receptor are expressed in microglia, but no evidence suggesting the involvement of CSF2 in inflammation in the degenerating eye has been reported. We found that Csf2 transcripts were induced in the early phase of in vitro mouse adult retina culture, used as degeneration models, suggesting that CSF2 induction is one of the earliest events occurring in the pathology of retinal degeneration. The administration of CSF2 into the retina after systemic NaIO3 treatment increased the number of microglia. To examine the roles of CSF2 in retinal inflammation, we overexpressed CSF2 in retinal explants. Induction of CSF2 activated microglia and Müller glia, and the layer structure of the retina was severely perturbed. CC motif chemokine ligand 2 (Ccl2) and C-X-C motif chemokine ligand 10 (Cxcl10), both of which are expressed in activated microglia, were strongly induced by the expression of CSF2 in the retina. The addition of CSF2 to primary retinal microglia and the microglial cell lines MG5 and BV2 showed statistically significant increase in Ccl2 and Il1b transcripts. Furthermore, CSF2 induced proliferation, migration, and phagocytosis in MG5 and/or BV2. The effects of CSF2 on microglia were mild, suggesting that CSF2 induced strong inflammation in the context of the retinal environment.
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Someya H, Ito M, Nishio Y, Sato T, Harimoto K, Takeuchi M. Osteopontin-induced vascular hyperpermeability through tight junction disruption in diabetic retina. Exp Eye Res 2022; 220:109094. [PMID: 35490836 DOI: 10.1016/j.exer.2022.109094] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/17/2022] [Accepted: 04/25/2022] [Indexed: 11/29/2022]
Abstract
Diabetic retinopathy is a major cause of blindness in developed countries, and is characterized by deterioration of barrier function causing vascular hyperpermeability and retinal edema. Vascular endothelial growth factor (VEGF) is a major mediator of diabetic macular edema. Although anti-VEGF drugs are the first-line treatment for diabetic macular edema, some cases are refractory to anti-VEGF therapy. Osteopontin (OPN) is a phosphoglycoprotein with diverse functions and expressed in various cells and tissues. Elevated OPN level has been implicated in diabetic retinopathy, but whether OPN is involved in hyperpermeability remains unclear. Using streptozotocin-induced diabetic mice (STZ mice) and human retinal endothelial cells (HRECs), we tested the hypothesis that up-regulated OPN causes tight junction disruption, leading to vascular hyperpermeability. The serum and retinal OPN concentrations were elevated in STZ mice compared to controls. Intravitreal injection of anti-OPN neutralizing antibody (anti-OPN Ab) suppressed vascular hyperpermeability and prevented decreases in claudin-5 and ZO-1 gene expression levels in the retina of STZ mice. Immunohistochemical staining of retinal vessels in STZ mice revealed claudin-5 immunoreactivity with punctate distribution and attenuated ZO-1 immunoreactivity, and these changes were prevented by anti-OPN Ab. Intravitreal injection of anti-OPN Ab did not change VEGF gene expression or protein concentration in retina of STZ mice. In an in vitro study, HRECs were exposed to normal glucose or high glucose with or without OPN for 48 h, and barrier function was evaluated by transendothelial electrical resistance and Evans blue permeation. Barrier function deteriorated under high glucose condition, and was further exacerbated by the addition of OPN. Immunofluorescence localization of claudin-5 and ZO-1 demonstrated punctate appearance with discontinuous junction in HRECs exposed to high glucose and OPN. There were no changes in VEGF and VEGF receptor-2 expression levels in HRECs by exposure to OPN. Our results suggest that OPN induces tight junction disruption and vascular hyperpermeability under diabetic conditions. Targeting OPN may be an effective approach to manage diabetic retinopathy.
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Affiliation(s)
- Hideaki Someya
- Department of Ophthalmology, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama, 359-8513, Japan
| | - Masataka Ito
- Department of Developmental Anatomy and Regenerative Biology, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama, 359-8513, Japan
| | - Yoshiaki Nishio
- Department of Ophthalmology, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama, 359-8513, Japan
| | - Tomohito Sato
- Department of Ophthalmology, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama, 359-8513, Japan
| | - Kozo Harimoto
- Department of Ophthalmology, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama, 359-8513, Japan
| | - Masaru Takeuchi
- Department of Ophthalmology, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama, 359-8513, Japan.
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Cai L, Gong Q, Qi L, Xu T, Suo Q, Li X, Wang W, Jing Y, Yang D, Xu Z, Yuan F, Tang Y, Yang G, Ding J, Chen H, Tian H. ACT001 attenuates microglia-mediated neuroinflammation after traumatic brain injury via inhibiting AKT/NFκB/NLRP3 pathway. Cell Commun Signal 2022; 20:56. [PMID: 35461293 PMCID: PMC9035258 DOI: 10.1186/s12964-022-00862-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 03/12/2022] [Indexed: 12/20/2022] Open
Abstract
Abstract
Background
Microglia-mediated neuroinflammatory response following traumatic brain injury (TBI) is considered as a vital secondary injury factor, which drives trauma-induced neurodegeneration and is lack of efficient treatment. ACT001, a sesquiterpene lactone derivative, is reportedly involved in alleviation of inflammatory response. However, little is known regarding its function in regulating innate immune response of central nervous system (CNS) after TBI. This study aimed to investigate the role and underlying mechanism of ACT001 in TBI.
Methods
Controlled cortical impact (CCI) models were used to establish model of TBI. Cresyl violet staining, evans blue extravasation, neurobehavioral function assessments, immunofluorescence and transmission electron microscopy were used to evaluate therapeutic effects of ACT001 in vivo. Microglial depletion was induced by administering mice with colony stimulating factor 1 receptor (CSF1R) inhibitor, PLX5622. Cell-cell interaction models were established as co-culture system to simulate TBI conditions in vitro. Cytotoxic effect of ACT001 on cell viability was assessed by cell counting kit-8 and activation of microglia cells were induced by Lipopolysaccharides (LPS). Pro-inflammatory cytokines expression was determined by Real-time PCR and nitric oxide production. Apoptotic cells were detected by TUNEL and flow cytometry assays. Tube formation was performed to evaluate cellular angiogenic ability. ELISA and western blot experiments were used to determine proteins expression. Pull-down assay was used to analyze proteins that bound ACT001.
Results
ACT001 relieved the extent of blood-brain barrier integrity damage and alleviated motor function deficits after TBI via reducing trauma-induced activation of microglia cells. Delayed depletion of microglia with PLX5622 hindered therapeutic effect of ACT001. Furthermore, ACT001 alleviated LPS-induced activation in mouse and rat primary microglia cells. Besides, ACT001 was effective in suppressing LPS-induced pro-inflammatory cytokines production in BV2 cells, resulting in reduction of neuronal apoptosis in HT22 cells and improvement of tube formation in bEnd.3 cells. Mechanism by which ACT001 functioned was related to AKT/NFκB/NLRP3 pathway. ACT001 restrained NFκB nuclear translocation in microglia cells through inhibiting AKT phosphorylation, resulting in decrease of NLRP3 inflammasome activation, and finally down-regulated microglial neuroinflammatory response.
Conclusions
Our study indicated that ACT001 played critical role in microglia-mediated neuroinflammatory response and might be a novel potential chemotherapeutic drug for TBI.
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Yemanyi F, Bora K, Blomfield AK, Wang Z, Chen J. Wnt Signaling in Inner Blood-Retinal Barrier Maintenance. Int J Mol Sci 2021; 22:11877. [PMID: 34769308 PMCID: PMC8584977 DOI: 10.3390/ijms222111877] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 12/14/2022] Open
Abstract
The retina is a light-sensing ocular tissue that sends information to the brain to enable vision. The blood-retinal barrier (BRB) contributes to maintaining homeostasis in the retinal microenvironment by selectively regulating flux of molecules between systemic circulation and the retina. Maintaining such physiological balance is fundamental to visual function by facilitating the delivery of nutrients and oxygen and for protection from blood-borne toxins. The inner BRB (iBRB), composed mostly of inner retinal vasculature, controls substance exchange mainly via transportation processes between (paracellular) and through (transcellular) the retinal microvascular endothelium. Disruption of iBRB, characterized by retinal edema, is observed in many eye diseases and disturbs the physiological quiescence in the retina's extracellular space, resulting in vision loss. Consequently, understanding the mechanisms of iBRB formation, maintenance, and breakdown is pivotal to discovering potential targets to restore function to compromised physiological barriers. These unraveled targets can also inform potential drug delivery strategies across the BRB and the blood-brain barrier into retinas and brain tissues, respectively. This review summarizes mechanistic insights into the development and maintenance of iBRB in health and disease, with a specific focus on the Wnt signaling pathway and its regulatory role in both paracellular and transcellular transport across the retinal vascular endothelium.
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Affiliation(s)
| | | | | | | | - Jing Chen
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (F.Y.); (K.B.); (A.K.B.); (Z.W.)
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