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Chen Z, Liu B, Zhou D, Lei M, Yang J, Hu Z, Duan W. AQP4 regulates ferroptosis and oxidative stress of Muller cells in diabetic retinopathy by regulating TRPV4. Exp Cell Res 2024; 439:114087. [PMID: 38735619 DOI: 10.1016/j.yexcr.2024.114087] [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: 12/07/2023] [Revised: 05/06/2024] [Accepted: 05/10/2024] [Indexed: 05/14/2024]
Abstract
Diabetic retinopathy (DR) is a common microvascular complication that causes visual impairment or loss. Aquaporin 4 (AQP4) is a regulatory protein involved in water transport and metabolism. In previous studies, we found that AQP4 is related to hypoxia injury in Muller cells. Transient receptor potential cation channel subfamily V member 4 (TRPV4) is a non-selective cation channel protein involved in the regulation of a variety of ophthalmic diseases. However, the effects of AQP4 and TRPV4 on ferroptosis and oxidative stress in high glucose (HG)-treated Muller cells are unclear. In this study, we investigated the functions of AQP4 and TRPV4 in DR. HG was used to treat mouse Muller cells. Reverse transcription quantitative polymerase chain reaction was used to measure AQP4 mRNA expression. Western blotting was used to detect the protein levels of AQP4, PTGS2, GPX4, and TRPV4. Cell count kit-8, flow cytometry, 5,5',6,6'-tetrachloro-1,1,3,3'-tetraethylbenzimidazolyl carbocyanine iodide staining, and glutathione (GSH), superoxide dismutase (SOD), and malondialdehyde (MDA) kits were used to evaluate the function of the Muller cells. Streptozotocin was used to induce DR in rats. Haematoxylin and eosin staining was performed to stain the retina of rats. GSH, SOD, and MDA detection kits, immunofluorescence, and flow cytometry assays were performed to study the function of AQP4 and TRPV4 in DR rats. Results found that AQP4 and TRPV4 were overexpressed in HG-induced Muller cells and streptozotocin-induced DR rats. AQP4 inhibition promoted proliferation and cell cycle progression, repressed cell apoptosis, ferroptosis, and oxidative stress, and alleviated retinal injury in DR rats. Mechanistically, AQP4 positively regulated TRPV4 expression. Overexpression of TRPV4 enhanced ferroptosis and oxidative stress in HG-treated Muller cells, and inhibition of TRPV4 had a protective effect on DR-induced retinal injury in rats. In conclusion, inhibition of AQP4 inhibits the ferroptosis and oxidative stress in Muller cells by downregulating TRPV4, which may be a potential target for DR therapy.
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Affiliation(s)
- Zhen Chen
- Department of Ophthalmology, The First People's Hospital of Yunnan Province, Kunming, 650032, Yunnan, China; The Affiliated Hospital of Kunming University of Science and Technology, Kunming, 650032, Yunnan, China.
| | - Bingjie Liu
- The Affiliated Hospital of Kunming University of Science and Technology, Kunming, 650032, Yunnan, China
| | - Daijiao Zhou
- Department of Ophthalmology, The First People's Hospital of Yunnan Province, Kunming, 650032, Yunnan, China
| | - Mingshu Lei
- Department of Ophthalmology, The First People's Hospital of Yunnan Province, Kunming, 650032, Yunnan, China
| | - Jingying Yang
- Department of Ophthalmology, The First People's Hospital of Yunnan Province, Kunming, 650032, Yunnan, China; The Affiliated Hospital of Kunming University of Science and Technology, Kunming, 650032, Yunnan, China
| | - Zhongyin Hu
- Department of Ophthalmology, The First People's Hospital of Yunnan Province, Kunming, 650032, Yunnan, China; The Affiliated Hospital of Kunming University of Science and Technology, Kunming, 650032, Yunnan, China
| | - Wenhua Duan
- Department of Ophthalmology, The First People's Hospital of Yunnan Province, Kunming, 650032, Yunnan, China; The Affiliated Hospital of Kunming University of Science and Technology, Kunming, 650032, Yunnan, China
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Deng X, Mo Y, Zhu X. Deciphering Müller cell heterogeneity signatures in diabetic retinopathy across species: an integrative single-cell analysis. Eur J Med Res 2024; 29:265. [PMID: 38698486 PMCID: PMC11067085 DOI: 10.1186/s40001-024-01847-y] [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: 01/13/2024] [Accepted: 04/17/2024] [Indexed: 05/05/2024] Open
Abstract
Diabetic retinopathy (DR), a leading cause of visual impairment, demands a profound comprehension of its cellular mechanisms to formulate effective therapeutic strategies. Our study presentes a comprehensive single-cell analysis elucidating the intricate landscape of Müller cells within DR, emphasizing their nuanced involvement. Utilizing scRNA-seq data from both Sprague-Dawley rat models and human patients, we delineated distinct Müller cell clusters and their corresponding gene expression profiles. These findings were further validated through differential gene expression analysis utilizing human transcriptomic data. Notably, certain Müller cell clusters displayed upregulation of the Rho gene, implying a phagocytic response to damaged photoreceptors within the DR microenvironment. This phenomenon was consistently observed across species. Additionally, the co-expression patterns of RHO and PDE6G within Müller cell clusters provided compelling evidence supporting their potential role in maintaining retinal integrity during DR. Our results offer novel insights into the cellular dynamics of DR and underscore Müller cells as promising therapeutic targets for preserving vision in retinal disorders induced by diabetes.
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Affiliation(s)
- Xiyuan Deng
- Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Ya Mo
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China.
| | - Xiuying Zhu
- Chengdu University of Traditional Chinese Medicine, Chengdu, China
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Du X, Butler AG, Chen HY. Cell-cell interaction in the pathogenesis of inherited retinal diseases. Front Cell Dev Biol 2024; 12:1332944. [PMID: 38500685 PMCID: PMC10944940 DOI: 10.3389/fcell.2024.1332944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/06/2024] [Indexed: 03/20/2024] Open
Abstract
The retina is part of the central nervous system specialized for vision. Inherited retinal diseases (IRD) are a group of clinically and genetically heterogenous disorders that lead to progressive vision impairment or blindness. Although each disorder is rare, IRD accumulatively cause blindness in up to 5.5 million individuals worldwide. Currently, the pathophysiological mechanisms of IRD are not fully understood and there are limited treatment options available. Most IRD are caused by degeneration of light-sensitive photoreceptors. Genetic mutations that abrogate the structure and/or function of photoreceptors lead to visual impairment followed by blindness caused by loss of photoreceptors. In healthy retina, photoreceptors structurally and functionally interact with retinal pigment epithelium (RPE) and Müller glia (MG) to maintain retinal homeostasis. Multiple IRD with photoreceptor degeneration as a major phenotype are caused by mutations of RPE- and/or MG-associated genes. Recent studies also reveal compromised MG and RPE caused by mutations in ubiquitously expressed ciliary genes. Therefore, photoreceptor degeneration could be a direct consequence of gene mutations and/or could be secondary to the dysfunction of their interaction partners in the retina. This review summarizes the mechanisms of photoreceptor-RPE/MG interaction in supporting retinal functions and discusses how the disruption of these processes could lead to photoreceptor degeneration, with an aim to provide a unique perspective of IRD pathogenesis and treatment paradigm. We will first describe the biology of retina and IRD and then discuss the interaction between photoreceptors and MG/RPE as well as their implications in disease pathogenesis. Finally, we will summarize the recent advances in IRD therapeutics targeting MG and/or RPE.
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Affiliation(s)
| | | | - Holly Y. Chen
- Department of Cell, Developmental and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
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Wolf HN, Ehinger V, Guempelein L, Banerjee P, Kuempfel T, Havla J, Pauly D. NMOSD IgG Impact Retinal Cells in Murine Retinal Explants. Curr Issues Mol Biol 2023; 45:7319-7335. [PMID: 37754247 PMCID: PMC10529972 DOI: 10.3390/cimb45090463] [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: 07/18/2023] [Revised: 08/29/2023] [Accepted: 09/05/2023] [Indexed: 09/28/2023] Open
Abstract
Neuromyelitis optica spectrum disorders (NMOSD) are chronic inflammatory diseases of the central nervous system, characterized by autoantibodies against aquaporin-4. The symptoms primarily involve severe optic neuritis and longitudinally extensive transverse myelitis. Although the disease progression is typically relapse-dependent, recent studies revealed retinal neuroaxonal degeneration unrelated to relapse activity, potentially due to anti-aquaporin-4-positive antibodies interacting with retinal glial cells such as Müller cells. In this exploratory study, we analysed the response of mouse retinal explants to NMOSD immunoglobulins (IgG). Mouse retinal explants were treated with purified IgG from patient or control sera for one and three days. We characterized tissue response patterns through morphological changes, chemokine secretion, and complement expression. Mouse retinal explants exhibited a basic proinflammatory response ex vivo, modified by IgG addition. NMOSD IgG, unlike control IgG, increased gliosis and decreased chemokine release (CCL2, CCL3, CCL4, and CXCL-10). Complement component expression by retinal cells remained unaltered by either IgG fraction. We conclude that human NMOSD IgG can possibly bind in the mouse retina, altering the local cellular environment. This intraretinal stress may contribute to retinal degeneration independent of relapse activity in NMOSD, suggesting a primary retinopathy.
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Affiliation(s)
- Hannah Nora Wolf
- Department of Experimental Ophthalmology, University Marburg, 35037 Marburg, Germany
| | - Veronika Ehinger
- Department of Experimental Ophthalmology, University Marburg, 35037 Marburg, Germany
| | - Larissa Guempelein
- Department of Experimental Ophthalmology, University Marburg, 35037 Marburg, Germany
| | - Pratiti Banerjee
- Department of Experimental Ophthalmology, University Marburg, 35037 Marburg, Germany
| | - Tania Kuempfel
- Institute of Clinical Neuroimmunology, Biomedical Center and University Hospital, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Joachim Havla
- Institute of Clinical Neuroimmunology, Biomedical Center and University Hospital, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Diana Pauly
- Department of Experimental Ophthalmology, University Marburg, 35037 Marburg, Germany
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Zhang Y, Yang X, Deng X, Yang S, Li Q, Xie Z, Hong L, Cao M, Yi G, Fu M. Single-cell transcriptomics-based multidisease analysis revealing the molecular dynamics of retinal neurovascular units under inflammatory and hypoxic conditions. Exp Neurol 2023; 362:114345. [PMID: 36736650 DOI: 10.1016/j.expneurol.2023.114345] [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: 10/10/2022] [Revised: 12/27/2022] [Accepted: 01/29/2023] [Indexed: 02/05/2023]
Abstract
The retinal neurovascular unit (NVU) is paramount to maintaining the homeostasis of the retina and determines the progression of various diseases, including diabetic retinopathy (DR), glaucoma, and retinopathy of prematurity (ROP). Although some studies have investigated these diseases, a combined analysis of disease-wide etiology in the NUV at the single-cell level is lacking. Herein, we constructed an atlas of the NVU under inflammatory and hypoxic conditions by integrating single-cell transcriptome data from retinas from wild-type, AireKO, and NdpKO mice. Based on the heterogeneity of the NVU structure and transcriptome diversity under normal and pathological conditions, we discovered two subpopulations of Müller cells: Aqp4hi and Aqp4lo cells. Specifically, Aqp4lo cells expresses phototransduction genes and represent a special type of Müller cell distinct from Aqp4hi cells, classical Müller cells. AireKO mice exhibit experimental autoimmune uveitis (EAU) with severe damage to the NVU structure, mainly degeneration of Aqp4hi cells. NdpKO mice exhibited familial exudative vitreoretinopathy (FEVR), with damage to the endothelial barrier, endothelial cell tight junction destruction and basement membrane thickening, accompanied by the reactive secretion of proangiogenic factors by Aqp4hi cells. In both EAU and FEVR, Aqp4hi cells are a key factor leading to NVU damage, and the mechanism by which they are generated is regulated by different transcription factors. By studying the pattern of immune cell infiltration in AireKO mice, we constructed a regulatory loop of "inflammatory cells/NVU - monocytes - APCs - Ifng+ T cells", providing a new target for blocking the inflammatory cascade. Our elucidation of the cell-specific molecular changes, cell-cell interactions and transcriptional mechanisms of the retinal NVU provides new insights to support the development of multipurpose drugs to block or even reverse NVU damage.
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Affiliation(s)
- Yuxi Zhang
- Zhujiang Hospital, Southern Medical University, Guangzhou, PR China; The Second Clinical School, Southern Medical University, Guangzhou, Guangdong, PR China
| | - Xiongyi Yang
- Zhujiang Hospital, Southern Medical University, Guangzhou, PR China; The Second Clinical School, Southern Medical University, Guangzhou, Guangdong, PR China
| | - Xiaoqing Deng
- Zhujiang Hospital, Southern Medical University, Guangzhou, PR China; The Second Clinical School, Southern Medical University, Guangzhou, Guangdong, PR China
| | - Siyu Yang
- Department of Ophthalmology, The Seventh Affiliated Hospital, Sun Yat-Sen University, Shenzhen, PR China
| | - Qiumo Li
- Zhujiang Hospital, Southern Medical University, Guangzhou, PR China; The Second Clinical School, Southern Medical University, Guangzhou, Guangdong, PR China
| | - Zhuohang Xie
- Zhujiang Hospital, Southern Medical University, Guangzhou, PR China; The Second Clinical School, Southern Medical University, Guangzhou, Guangdong, PR China
| | - Libing Hong
- Zhujiang Hospital, Southern Medical University, Guangzhou, PR China; The Second Clinical School, Southern Medical University, Guangzhou, Guangdong, PR China
| | - Mingzhe Cao
- Department of Ophthalmology, The Seventh Affiliated Hospital, Sun Yat-Sen University, Shenzhen, PR China.
| | - Guoguo Yi
- Department of Ophthalmology, The Sixth Affiliated Hospital, Sun Yat-Sen University, No. 26, Erheng Road, Yuancun, Tianhe, Guangzhou, Guangdong, PR China.
| | - Min Fu
- Department of Ophthalmology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, PR China.
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Structure-function correlates of vision loss in neuromyelitis optica spectrum disorders. Sci Rep 2022; 12:17545. [PMID: 36266394 PMCID: PMC9585067 DOI: 10.1038/s41598-022-19848-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 09/06/2022] [Indexed: 01/13/2023] Open
Abstract
Optic neuritis (ON) in neuromyelitis optica spectrum disorders (NMOSD) regularly leads to more profound vision loss compared to multiple sclerosis (MS) and myelin-oligodendrocyte-glycoprotein-antibody associated disease (MOGAD). Here we investigate ON-related vision loss in NMOSD compared to MS and MOGAD in order to identify neuroaxonal and retinal contributors to visual dysfunction. In this retrospective study we included patients with aquaporin-4-antibody seropositive NMOSD (n = 28), MOGAD (n = 14), MS (n = 29) and controls (n = 14). We assessed optic nerve damage and fovea morphometry by optical coherence tomography. Visual function was assessed as high (HCVA) and low contrast visual acuity (LCVA), and visual fields' mean deviation (MD). In all diseases, lower visual function was associated with peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell and inner plexiform layer (GCIP) thinning following a broken stick model, with pRNFL and GCIP cutoff point at ca. 60 µm. HCVA loss per µm pRNFL and GCIP thinning was stronger in NMOSD compared with MOGAD. Foveal inner rim volume contributed to MD and LCVA in NMOSD eyes, only. Together these data supports that visual dysfunction in NMOSD is associated with neuroaxonal damage beyond the effect seen in MS and MOGAD. A primary retinopathy, respectively Müller cell pathology, may contribute to this effect.
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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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Abe Y, Yasui M. Aquaporin-4 in Neuromyelitis Optica Spectrum Disorders: A Target of Autoimmunity in the Central Nervous System. Biomolecules 2022; 12:biom12040591. [PMID: 35454180 PMCID: PMC9030581 DOI: 10.3390/biom12040591] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/11/2022] [Accepted: 04/12/2022] [Indexed: 12/20/2022] Open
Abstract
Since the discovery of a specific autoantibody in patients with neuromyelitis optica spectrum disorder (NMOSD) in 2004, the water channel aquaporin-4 (AQP4) has attracted attention as a target of autoimmune diseases of the central nervous system. In NMOSD, the autoantibody (NMO-IgG) binds to the extracellular loops of AQP4 as expressed in perivascular astrocytic end-feet and disrupts astrocytes in a complement-dependent manner. NMO-IgG is an excellent marker for distinguishing the disease from other inflammatory demyelinating diseases, such as multiple sclerosis. The unique higher-order structure of AQP4—called orthogonal arrays of particles (OAPs)—as well as its subcellular localization may play a crucial role in the pathogenesis of the disease. Recent studies have also demonstrated complement-independent cytotoxic effects of NMO-IgG. Antibody-induced endocytosis of AQP4 has been suggested to be involved in this mechanism. This review focuses on the binding properties of antibodies that recognize the extracellular region of AQP4 and the characteristics of AQP4 that are implicated in the pathogenesis of NMOSD.
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Affiliation(s)
- Yoichiro Abe
- Department of Pharmacology, Keio University School of Medicine, Tokyo 160-8582, Japan
- Keio University Global Research Institute, Tokyo 108-8345, Japan
- Correspondence: (Y.A.); (M.Y.); Tel.: +81-3-5363-3751 (M.Y.)
| | - Masato Yasui
- Department of Pharmacology, Keio University School of Medicine, Tokyo 160-8582, Japan
- Keio University Global Research Institute, Tokyo 108-8345, Japan
- Correspondence: (Y.A.); (M.Y.); Tel.: +81-3-5363-3751 (M.Y.)
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Cellular Distribution of Brain Aquaporins and Their Contribution to Cerebrospinal Fluid Homeostasis and Hydrocephalus. Biomolecules 2022; 12:biom12040530. [PMID: 35454119 PMCID: PMC9025855 DOI: 10.3390/biom12040530] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 01/19/2023] Open
Abstract
Brain aquaporins facilitate the movement of water between the four water compartments: blood, cerebrospinal fluid, interstitial fluid, and intracellular fluid. This work analyzes the expression of the four most abundant aquaporins (AQPs) (AQP1, AQP4, AQP9, and AQP11) in the brains of mice and discuss their contribution to hydrocephalus. We analyzed available data from single-cell RNA sequencing of the central nervous system of mice to describe the expression of aquaporins and compare their distribution with that based on qPCR, western blot, and immunohistochemistry assays. Expression of AQP1 in the apical cell membrane of choroid plexus epithelial cells and of AQP4 in ependymal cells, glia limitans, and astrocyte processes in the pericapillary end foot is consistent with the involvement of both proteins in cerebrospinal fluid homeostasis. The expression of both aquaporins compensates for experimentally induced hydrocephalus in the animals. Recent data demonstrate that hypoxia in aged animals alters AQP4 expression in the choroidal plexus and cortex, increasing the ventricle size and intraventricular pressure. Cerebral distensibility is reduced in parallel with a reduction in cerebrospinal fluid drainage and cognitive deterioration. We propose that aged mice chronically exposed to hypoxia represent an excellent experimental model for studying the pathophysiological characteristics of idiopathic normal pressure hydrocephalus and roles for AQPs in such disease.
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