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Ambery P, Greasley PJ, Menzies RI, Brynne L, Kulkarni S, Oscarsson J, Davenport AP. Targeting the endothelium by combining endothelin-1 antagonism and SGLT-2 inhibition: better together? Clin Sci (Lond) 2024; 138:687-697. [PMID: 38835256 DOI: 10.1042/cs20240605] [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: 03/28/2024] [Revised: 05/17/2024] [Accepted: 05/22/2024] [Indexed: 06/06/2024]
Abstract
Endothelin A and B receptors, together with sodium-glucose cotransporter-2 (SGLT-2) channels are important targets in improving endothelial function and intervention with inhibitors has been the subject of multiple mechanistic and clinical outcome trials over recent years. Notable successes include the treatment of pulmonary hypertension with endothelin receptor antagonists, and the treatment of heart failure and chronic kidney disease with SGLT-2 inhibitors. With distinct and complementary mechanisms, in this review, we explore the logic of combination therapy for a number of diseases which have endothelial dysfunction at their heart.
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Affiliation(s)
- Phil Ambery
- Clinical Late Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Peter J Greasley
- Early Clinical Development, Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Robert I Menzies
- Bioscience Renal, Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Lena Brynne
- Information Practice Late Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Spoorthy Kulkarni
- Department of Clinical Pharmacology and Therapeutics, Cambridge University Hospitals NHS Foundation Trust, Cambridge, CB20QQ, U.K
- Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Addenbrooke's Hospital, Cambridge, U.K
| | - Jan Oscarsson
- Clinical Late Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Anthony P Davenport
- Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Addenbrooke's Hospital, Cambridge, U.K
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2
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Li X, Fu YH, Tong XW, Zhang YT, Shan YY, Xu YX, Pu SD, Gao XY. RAAS in diabetic retinopathy: mechanisms and therapies. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2024; 68:e230292. [PMID: 38652701 PMCID: PMC11081058 DOI: 10.20945/2359-4292-2023-0292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 11/23/2023] [Indexed: 04/25/2024]
Abstract
Diabetic retinopathy (DR) is a complication of diabetes with a complex pathophysiology and multiple factors involved. Recently, it has been found that the upregulation of the renin-angiotensin-aldosterone system (RAAS) leads to overexpression of angiotensin II (Ang II), which induces oxidative stress, inflammation, and angiogenesis in the retina. Therefore, RAAS may be a promising therapeutic target in DR. Notably, RAAS inhibitors are often used in the treatment of hypertension. Still, the potential role and mechanism of DR must be further studied. In this review, we discuss and summarize the pathology and potential therapeutic goals of RAAS in DR.
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Affiliation(s)
- Xin Li
- First Affiliated Hospital of Harbin Medical University, Harbin Medical University, Department of Endocrinology, Harbin, China
| | - Yu-Hong Fu
- First Affiliated Hospital of Harbin Medical University, Harbin Medical University, Department of Endocrinology, Harbin, China
| | - Xue-Wei Tong
- First Affiliated Hospital of Harbin Medical University, Harbin Medical University, Department of Endocrinology, Harbin, China
| | - Yi-Tong Zhang
- First Affiliated Hospital of Harbin Medical University, Harbin Medical University, Department of Endocrinology, Harbin, China
| | - Yong-Yan Shan
- First Affiliated Hospital of Harbin Medical University, Harbin Medical University, Department of Endocrinology, Harbin, China
| | - Yu-Xin Xu
- First Affiliated Hospital of Harbin Medical University, Harbin Medical University, Department of Endocrinology, Harbin, China
| | - Sheng-Dan Pu
- First Affiliated Hospital of Harbin Medical University, Harbin Medical University, Department of Endocrinology, Harbin, China
| | - Xin-Yuan Gao
- First Affiliated Hospital of Harbin Medical University, Harbin Medical University, Department of Endocrinology, Harbin, China,
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3
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Shigesada N, Shikada N, Shirai M, Toriyama M, Higashijima F, Kimura K, Kondo T, Bessho Y, Shinozuka T, Sasai N. Combination of blockade of endothelin signalling and compensation of IGF1 expression protects the retina from degeneration. Cell Mol Life Sci 2024; 81:51. [PMID: 38252153 PMCID: PMC10803390 DOI: 10.1007/s00018-023-05087-x] [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: 07/22/2023] [Revised: 12/01/2023] [Accepted: 12/12/2023] [Indexed: 01/23/2024]
Abstract
Retinitis pigmentosa (RP) and macular dystrophy (MD) cause severe retinal dysfunction, affecting 1 in 4000 people worldwide. This disease is currently assumed to be intractable, because effective therapeutic methods have not been established, regardless of genetic or sporadic traits. Here, we examined a RP mouse model in which the Prominin-1 (Prom1) gene was deficient and investigated the molecular events occurring at the outset of retinal dysfunction. We extracted the Prom1-deficient retina subjected to light exposure for a short time, conducted single-cell expression profiling, and compared the gene expression with and without stimuli. We identified the cells and genes whose expression levels change directly in response to light stimuli. Among the genes altered by light stimulation, Igf1 was decreased in rod photoreceptor cells and astrocytes under the light-stimulated condition. Consistently, the insulin-like growth factor (IGF) signal was weakened in light-stimulated photoreceptor cells. The recovery of Igf1 expression with the adeno-associated virus (AAV) prevented photoreceptor cell death, and its treatment in combination with the endothelin receptor antagonist led to the blockade of abnormal glial activation and the promotion of glycolysis, thereby resulting in the improvement of retinal functions, as assayed by electroretinography. We additionally demonstrated that the attenuation of mammalian/mechanistic target of rapamycin (mTOR), which mediates IGF signalling, leads to complications in maintaining retinal homeostasis. Together, we propose that combinatorial manipulation of distinct mechanisms is useful for the maintenance of the retinal condition.
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Affiliation(s)
- Naoya Shigesada
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, 630-0192, Japan
| | - Naoya Shikada
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, 630-0192, Japan
| | - Manabu Shirai
- Omics Research Center (ORC), National Cerebral and Cardiovascular Center, Suita, Osaka, 564-8565, Japan
| | - Michinori Toriyama
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda, 669-1337, Japan
| | - Fumiaki Higashijima
- Department of Ophthalmology, Graduate School of Medicine, Yamaguchi University, Ube, 755-0046, Japan
| | - Kazuhiro Kimura
- Department of Ophthalmology, Graduate School of Medicine, Yamaguchi University, Ube, 755-0046, Japan
| | - Toru Kondo
- Division of Stem Cell Biology, Institute for Genetic Medicine, Hokkaido University, Sapporo, 060-0815, Japan
| | - Yasumasa Bessho
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, 630-0192, Japan
| | - Takuma Shinozuka
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, 630-0192, Japan
| | - Noriaki Sasai
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, 630-0192, Japan.
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4
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Giri AK, Prasad G, Parekatt V, Rajashekar D, Tandon N, Bharadwaj D. Epigenome-wide methylation study identified two novel CpGs associated with T2DM risk and a network of co-methylated CpGs capable of patient's classifications. Hum Mol Genet 2023; 32:2576-2586. [PMID: 37184252 DOI: 10.1093/hmg/ddad084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 04/24/2023] [Accepted: 05/11/2023] [Indexed: 05/16/2023] Open
Abstract
Prevention of Type 2 diabetes mellitus (T2DM) pandemic needs markers that can precisely predict the disease risk in an individual. Alterations in DNA methylations due to exposure towards environmental risk factors are widely sought markers for T2DM risk prediction. To identify such individual DNA methylation signatures and their effect on disease risk, we performed an epigenome-wide association study (EWAS) in 844 Indian individuals of Indo-European origin. We identified and validated methylation alterations at two novel CpG sites in MIR1287 (cg01178710) and EDN2-SCMH1 (cg04673737) genes associated with T2DM risk at the epigenome-wide-significance-level (P < 1.2 × 10-7). Further, we also replicated the association of two known CpG sites in TXNIP, and CPT1A in the Indian population. With 535 EWAS significant CpGs (P < 1.2 × 10-7) identified in the discovery phase samples, we created a co-methylation network using weighted correlation network analysis and identified four modules among the CpGs. We observed that methylation of one of the module associates with T2DM risk factors (e.g. BMI, insulin and C-peptide) and can be used as markers to segregate T2DM patients with good glycemic control (e.g. low HbA1c) and dyslipidemia (low HDL and high TG) from the other patients. Additionally, an intronic SNP (rs6503650) in the JUP gene, a member of the same module, associated with methylation at all the 14 hub CpG sites of that module as methQTL. Our network-assisted EWAS is the first to systematically explore DNA methylation variations conferring risks to T2DM in Indians and use the identified risk CpG sites for patient segregation with different clinical outcomes. These findings can be useful for better stratification of patients to improve the clinical management and treatment effects.
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Affiliation(s)
- Anil K Giri
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi 110025, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Gauri Prasad
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi 110025, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Vaisak Parekatt
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi 110025, India
| | - Donaka Rajashekar
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi 110025, India
| | - Nikhil Tandon
- Department of Endocrinology and Metabolism, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Dwaipayan Bharadwaj
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Systems Genomics Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
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5
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Chen X, Liu C, Cui Z, Huang Y, Luo Q, Chen S, Wang X, Hou X, Gong Q, Li Y, Qiu J, Zhang Y, Chen P, Yang Y, Zhuang J, Yu K. Integrative transcriptomics analysis and experimental validation reveal immunomodulatory patterns in keratoconus. Exp Eye Res 2023; 230:109460. [PMID: 37001853 DOI: 10.1016/j.exer.2023.109460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 02/10/2023] [Accepted: 03/25/2023] [Indexed: 03/31/2023]
Abstract
Keratoconus is a progressive disorder of the cornea and is typically considered a noninflammatory disease. However, increasing evidence indicates that immune disorders play an essential role in keratoconus progression, but the immune-related etiology remains elusive. Here, we comprehensively utilized bioinformatics approaches and experimental methods to explore the potential immunoregulatory mechanism of keratoconus progression. Transcriptomics data containing two keratoconus patient groups was derived from the public dataset GSE151631. The intersection of genes and known immunological genes was used to obtain differentially expressed immune-related genes. We utilized various protein clustering algorithms to screen out and validated the hub immune-related genes, and further explored their potential biological functions via gene annotation and pathway enrichment analyses. Moreover, the underlying immune landscape and drug targets were predicted by immune cell infiltration analysis and drug-gene interaction analysis. Furthermore, keratoconus-related immunoregulatory competitive endogenous RNA networks were constructed and experimentally validated. After filtering and experimental validation, nine keratoconus-associated immune-related genes were credible. Infiltrated monocytes might play an essential role in the progression of keratoconus. Moreover, eleven intersecting drugs targeting four genes, CCR2, CCR5, F2RL1, and ADORA1, were considered as potential druggable molecular targets for keratoconus. Furthermore, in the competitive endogenous RNA network, we identified several lncRNAs and miRNAs as critical noncoding RNAs regulating the hub genes. Overall, our data indicated that the immunomodulatory patterns had undergone changes in the pathogenesis of keratoconus, which might facilitate the understanding of keratoconus-related immune processes and provide novel insights into developing new immunotherapies for keratoconus.
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6
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Astrocyte Immune Functions and Glaucoma. Int J Mol Sci 2023; 24:ijms24032747. [PMID: 36769067 PMCID: PMC9916878 DOI: 10.3390/ijms24032747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/26/2023] [Accepted: 01/26/2023] [Indexed: 02/04/2023] Open
Abstract
Astrocytes, a non-neuronal glial cell type in the nervous system, are essential for regulating physiological functions of the central nervous system. In various injuries and diseases of the central nervous system, astrocytes often change their phenotypes into neurotoxic ones that participate in pro-inflammatory responses (hereafter referred to as "immune functions"). Such astrocytic immune functions are not only limited to brain diseases but are also found in ocular neurodegenerative diseases such as glaucoma, a retinal neurodegenerative disease that is the leading cause of blindness worldwide. The eye has two astrocyte-lineage cells: astrocytes and Müller cells. They maintain the physiological environment of the retina and optic nerve, thereby controlling visual function. Dysfunction of astrocyte-lineage cells may be involved in the onset and progression of glaucoma. These cells become reactive in glaucoma patients, and animal studies have suggested that their immune responses may be linked to glaucoma-related events: tissue remodeling, neuronal death, and infiltration of peripheral immune cells. In this review, we discuss the role of the immune functions of astrocyte-lineage cells in the pathogenesis of glaucoma.
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7
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Sonny S, Yuan H, Chen S, Duncan MR, Chen P, Benny M, Young K, Park KK, Schmidt AF, Wu S. GSDMD deficiency ameliorates hyperoxia-induced BPD and ROP in neonatal mice. Sci Rep 2023; 13:143. [PMID: 36599874 DOI: 10.1038/s41598-022-27201-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 12/28/2022] [Indexed: 01/06/2023] Open
Abstract
Bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP) are among the most common morbidities affecting extremely premature infants who receive oxygen therapy. Many clinical studies indicate that BPD is associated with advanced ROP. However, the mechanistic link between hyperoxia, BPD, and ROP remains to be explored. Gasdermin D (GSDMD) is a key executor of inflammasome-induced pyroptosis and inflammation. Inhibition of GSDMD has been shown to attenuate hyperoxia-induced BPD and brain injury in neonatal mice. The objective of this study was to further define the mechanistic roles of GSDMD in the pathogenesis of hyperoxia-induced BPD and ROP in mouse models. Here we show that global GSDMD knockout (GSDMD-KO) protects against hyperoxia-induced BPD by reducing macrophage infiltration, improving alveolarization and vascular development, and decreasing cell death. In addition, GSDMD deficiency prevented hyperoxia-induced ROP by reducing vasoobliteration and neovascularization, improving thinning of multiple retinal tissue layers, and decreasing microglial activation. RNA sequencing analyses of lungs and retinas showed that similar genes, including those from inflammatory, cell death, tissue remodeling, and tissue and vascular developmental signaling pathways, were induced by hyperoxia and impacted by GSDMD-KO in both models. These data highlight the importance of GSDMD in the pathogenesis of BPD and ROP and suggest that targeting GSDMD may be beneficial in preventing and treating BPD and ROP in premature infants.
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Affiliation(s)
- Sarah Sonny
- Neonatology and Batchelor Children Research Institute, University of Miami Miller School of Medicine, 1580 NW 10thAve, Miami, FL, 33136, USA
| | - Huijun Yuan
- Neonatology and Batchelor Children Research Institute, University of Miami Miller School of Medicine, 1580 NW 10thAve, Miami, FL, 33136, USA
| | - Shaoyi Chen
- Neonatology and Batchelor Children Research Institute, University of Miami Miller School of Medicine, 1580 NW 10thAve, Miami, FL, 33136, USA
| | - Matthew R Duncan
- Neonatology and Batchelor Children Research Institute, University of Miami Miller School of Medicine, 1580 NW 10thAve, Miami, FL, 33136, USA
| | - Pingping Chen
- Neonatology and Batchelor Children Research Institute, University of Miami Miller School of Medicine, 1580 NW 10thAve, Miami, FL, 33136, USA
| | - Merline Benny
- Neonatology and Batchelor Children Research Institute, University of Miami Miller School of Medicine, 1580 NW 10thAve, Miami, FL, 33136, USA
| | - Karen Young
- Neonatology and Batchelor Children Research Institute, University of Miami Miller School of Medicine, 1580 NW 10thAve, Miami, FL, 33136, USA
| | - Kevin K Park
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, Miami, FL, USA
| | - Augusto F Schmidt
- Neonatology and Batchelor Children Research Institute, University of Miami Miller School of Medicine, 1580 NW 10thAve, Miami, FL, 33136, USA
| | - Shu Wu
- Neonatology and Batchelor Children Research Institute, University of Miami Miller School of Medicine, 1580 NW 10thAve, Miami, FL, 33136, USA.
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8
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Higashide T, Hirooka K, Kometani M, Sugiyama K. Aldosterone as a Possible Contributor to Eye Diseases. Endocrinology 2022; 164:6868238. [PMID: 36461718 DOI: 10.1210/endocr/bqac201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/10/2022] [Accepted: 11/29/2022] [Indexed: 12/07/2022]
Abstract
Aldosterone, an effector molecule of the renin-angiotensin-aldosterone system (RAAS), has been receiving more attention in the field of ophthalmology because of its possible role in the pathogenesis of various eye diseases or abnormalities; it may even become a target for their treatment. Primary aldosteronism, a typical model of a systemic aldosterone excess, may cause vision loss due to various ocular diseases, such as retinal vein occlusion, central serous chorioretinopathy, and, possibly glaucoma. RAAS components are present in various parts and types of cells present in the eye. Investigations of the local RAAS in various animal models of diabetic macular edema, retinal vein occlusion, retinopathy of prematurity, central serous chorioretinopathy, and glaucoma have found evidence that aldosterone or mineralocorticoid receptors may exacerbate the pathology of these disorders. Further studies are needed to elucidate whether the modulation of aldosterone or mineralocorticoid receptors is an effective treatment for preventing vision loss in patients with eye diseases.
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Affiliation(s)
- Tomomi Higashide
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Kazuyuki Hirooka
- Ophthalmology and Visual Science, Graduate School of Biomedical Science, Hiroshima University, Hiroshima, Japan
| | - Mitsuhiro Kometani
- Department of Health Promotion and Medicine of the Future, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Kazuhisa Sugiyama
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
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9
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Song Z, Chen B, Tsai CH, Wu D, Liu E, Hawkins IS, Phan A, Auman JT, Tao Y, Mei H. Differentiation Trajectory of Limbal Stem and Progenitor Cells under Normal Homeostasis and upon Corneal Wounding. Cells 2022; 11:cells11131983. [PMID: 35805068 PMCID: PMC9266118 DOI: 10.3390/cells11131983] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/06/2022] [Accepted: 06/14/2022] [Indexed: 11/16/2022] Open
Abstract
Limbal stem cells (LSCs) reside discretely at limbus surrounded by niche cells and progenitor cells. The aim of this study is to identify the heterogeneous cell populations at limbus under normal homeostasis and upon wounding using single-cell RNA sequencing in a mouse model. Two putative LSC types were identified which showed a differentiation trajectory into limbal progenitor cell (LPC) types under normal homeostasis and during wound healing. They were designated as “putative active LSCs” and “putative quiescent LSCs”, respectively, because the former type actively divided upon wounding while the later type stayed at a quiescent status upon wounding. The “putative quiescent LSCs” might contribute to a barrier function due to their characteristic markers regulating vascular and epithelial barrier and growth. Different types of LPCs at different proliferative statuses were identified in unwounded and wounded corneas with distinctive markers. Four maturation markers (Aldh3, Slurp1, Tkt, and Krt12) were screened out for corneal epithelium, which showed an increased expression along the differentiation trajectory during corneal epithelial maturation. In conclusion, our study identified two different types of putative LSCs and several types of putative LPCs under normal homeostasis and upon wounding, which will facilitate the understanding of corneal epithelial regeneration and wound healing.
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Affiliation(s)
- Zhenwei Song
- Department of Ophthalmology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (Z.S.); (C.-H.T.); (E.L.); (I.S.H.)
- School of Medicine, Hunan Normal University, 371 Tongzipo Road, Changsha 410081, China
| | - Brian Chen
- Department of Biostatistics, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (B.C.); (D.W.)
| | - Chi-Hao Tsai
- Department of Ophthalmology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (Z.S.); (C.-H.T.); (E.L.); (I.S.H.)
| | - Di Wu
- Department of Biostatistics, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (B.C.); (D.W.)
- Division of Oral and Craniofacial Health Research, Adams School of Dentistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Emily Liu
- Department of Ophthalmology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (Z.S.); (C.-H.T.); (E.L.); (I.S.H.)
| | - Isha Sharday Hawkins
- Department of Ophthalmology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (Z.S.); (C.-H.T.); (E.L.); (I.S.H.)
| | - Andrew Phan
- Department of Psychology and Neuroscience, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
| | - James Todd Auman
- Department of Pathology and Laboratory Medicine, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (J.T.A.); (Y.T.)
| | - Yazhong Tao
- Department of Pathology and Laboratory Medicine, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (J.T.A.); (Y.T.)
| | - Hua Mei
- Department of Ophthalmology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (Z.S.); (C.-H.T.); (E.L.); (I.S.H.)
- Department of Cell Biology and Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Correspondence:
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10
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Marola OJ, Howell GR, Libby RT. Vascular derived endothelin receptor A controls endothelin-induced retinal ganglion cell death. Cell Death Dis 2022; 8:207. [PMID: 35429992 PMCID: PMC9013356 DOI: 10.1038/s41420-022-00985-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/13/2022] [Accepted: 03/23/2022] [Indexed: 11/29/2022]
Abstract
Endothelin (EDN, also known as ET) signaling has been suggested to be an important mediator of retinal ganglion cell (RGC) death in glaucoma. Antagonism of EDN receptors (EDNRA and EDNRB, also known as ET-A and ET-B) prevented RGC death in mouse models of chronic ocular hypertension, and intravitreal injection of EDN ligand was sufficient to drive RGC death. However, it remains unclear which cell types EDN ligands directly affect to elicit RGC death. Multiple cell types in the retina and optic nerve express EDNRA and EDNRB and thus could respond to EDN ligands in the context of glaucoma. Here, we systematically deleted Edn receptors from specific cell types to identify the critical EDN receptor mediating RGC death in vivo. Deletion of both Ednra and Ednrb from retinal neurons (including RGCs) and macroglia did not prevent RGC loss after exposure to EDN1 ligands, suggesting EDN1 ligands cause RGC death via an indirect mechanism involving a secondary cell type. Deletion of Ednra from the full body, and then specifically from vascular mural cells, prevented EDN1-induced vasoconstriction and RGC death. Together, these data suggest EDN ligands cause RGC death via a mechanism initiated by vascular mural cells. It is possible RGC death is a consequence of vascular mural cell-induced vasoconstriction and its pathological sequelae. These results highlight the potential importance of neurovascular dysfunction in glaucoma.
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11
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Kobayashi Y, Watanabe S, Ong ALC, Shirai M, Yamashiro C, Ogata T, Higashijima F, Yoshimoto T, Hayano T, Asai Y, Sasai N, Kimura K. Early manifestations and differential gene expression associated with photoreceptor degeneration in Prom1-deficient retina. Dis Model Mech 2021; 14:272527. [PMID: 34664634 PMCID: PMC8628633 DOI: 10.1242/dmm.048962] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 10/08/2021] [Indexed: 12/13/2022] Open
Abstract
Retinitis pigmentosa (RP) and macular dystrophy (MD) are characterized by gradual photoreceptor death in the retina and are often associated with genetic mutations, including those in the prominin-1 (Prom1) gene. Prom1-knockout (KO) mice recapitulate key features of these diseases including light-dependent retinal degeneration and constriction of retinal blood vessels. The mechanisms underlying such degeneration have remained unclear, however. We here analysed early events associated with retinal degeneration in Prom1-KO mice. We found that photoreceptor cell death and glial cell activation occur between 2 and 3 weeks after birth. Whereas gene expression was not affected at 2 weeks, the expression of several genes was altered at 3 weeks in the Prom1-KO retina, with the expression of that for endothelin-2 (Edn2) being markedly upregulated. Expression of Edn2 was also induced by light stimulation in Prom1-KO mice reared in the dark. Treatment with endothelin receptor antagonists attenuated photoreceptor cell death, gliosis and retinal vessel stenosis in Prom1-KO mice. Our findings thus reveal early manifestations of retinal degeneration in a model of RP/MD and suggest potential therapeutic agents for these diseases. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Yuka Kobayashi
- Department of Ophthalmology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-kogushi, Ube 755-0046, Japan
| | - Shizuka Watanabe
- Developmental Biomedical Science, Division of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma 630-0192, Japan
| | - Agnes Lee Chen Ong
- Developmental Biomedical Science, Division of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma 630-0192, Japan
| | - Manabu Shirai
- Omics Research Center (ORC), National Cerebral and Cardiovascular Center, 6-1 Kishibe Shinmachi, Suita, Osaka 564-8565, Japan
| | - Chiemi Yamashiro
- Department of Ophthalmology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-kogushi, Ube 755-0046, Japan
| | - Tadahiko Ogata
- Department of Ophthalmology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-kogushi, Ube 755-0046, Japan
| | - Fumiaki Higashijima
- Department of Ophthalmology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-kogushi, Ube 755-0046, Japan
| | - Takuya Yoshimoto
- Department of Ophthalmology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-kogushi, Ube 755-0046, Japan
| | - Takahide Hayano
- Department of Systems Bioinformatics, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-kogushi, Ube 755-0046, Japan
| | - Yoshiyuki Asai
- Department of Systems Bioinformatics, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-kogushi, Ube 755-0046, Japan
| | - Noriaki Sasai
- Developmental Biomedical Science, Division of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma 630-0192, Japan
| | - Kazuhiro Kimura
- Department of Ophthalmology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-kogushi, Ube 755-0046, Japan
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12
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Li X, Lv J, Li J, Ren X. Kir4.1 may represent a novel therapeutic target for diabetic retinopathy (Review). Exp Ther Med 2021; 22:1021. [PMID: 34373707 PMCID: PMC8343704 DOI: 10.3892/etm.2021.10453] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 05/28/2021] [Indexed: 12/27/2022] Open
Abstract
As the major cause of irreversible loss of vision in adults, diabetic retinopathy (DR) is one of the most serious complications of diabetes. The imbalance of the retinal microenvironment and destruction of the blood-retinal barrier have a significant role in the progression of DR. Inward rectifying potassium channel 4.1 (Kir4.1) is located on Müller cells and is closely related to potassium homeostasis, water balance and glutamate clearance in the whole retina. The present review discusses the functions of Kir4.1 in regulating the retinal microenvironment and related biological mechanisms in DR. In the future, Kir4.1 may represent a novel alternative therapeutic target for DR through affecting the retinal microenvironment.
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Affiliation(s)
- Xiaoyu Li
- Department of Histology and Embryology, Dalian Medical University, Dalian, Liaoning 116044, P.R. China.,Department of Radiotherapy Oncology, The Second Hospital of Dalian Medical University, Dalian, Liaoning 116023, P.R. China
| | - Jiajun Lv
- Department of Histology and Embryology, Dalian Medical University, Dalian, Liaoning 116044, P.R. China.,Department of Radiotherapy Oncology, The Second Hospital of Dalian Medical University, Dalian, Liaoning 116023, P.R. China
| | - Jiazhi Li
- Department of Radiotherapy Oncology, The Second Hospital of Dalian Medical University, Dalian, Liaoning 116023, P.R. China
| | - Xiang Ren
- Department of Histology and Embryology, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
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13
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Dong K, Yang N, Ding J, Yan YY, Lu L, Wang YS. RNA interference targeting NOX4 protects visual function in an experimental model of retinal detachment by alleviating blood-retinal barrier damage. Int J Ophthalmol 2021; 14:50-56. [PMID: 33469483 DOI: 10.18240/ijo.2021.01.07] [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: 04/13/2020] [Accepted: 08/12/2020] [Indexed: 11/23/2022] Open
Abstract
AIM To observe the effects of the inhibition of NADPH oxidase 4 (NOX4) expression on the retinal vascular barriers and visual function after retinal detachment (RD). METHODS RD model was established 3wk after adeno-associaned virus vector injection. The retinal tissue was harvested 3d after RD, and the death of retinal vascular endothelial cells and photoreceptors was observed using electron microscopy. The NOX4 expression was detected by Western blot. Confocal microscopy was used to observe a retinal patch that had been perfused with Evans blue. A modified water maze test was used to detect the time required to find the platform on the water surface. The visual function of the rats was evaluated and reactive oxygen species (ROS) expression was detected by a fluorescence microplate reader. RESULTS The retinal patch showed that NOX4 interference significantly reduced the destruction of the tight junctions between the retinal endothelium of RD rats and reduced leakage. Western blotting showed decreased expression of the NOX4 protein and decreased expression of ROS in retinal tissue; the Morris water maze test results showed that NOX4 interference significantly decreased the escape latency of the rats. CONCLUSION NOX4 interference reduces the production of ROS in retinal vascular endothelial cells after experimental RD, thereby protecting the blood-retinal barrier and protecting visual function.
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Affiliation(s)
- Kai Dong
- Department of Ophthalmology, Anhui Provincial Hospital, Anhui Medical University, Hefei 230001, Anhui Province, China
| | - Nan Yang
- Department of Ophthalmology, Anhui Provincial Hospital, Anhui Medical University, Hefei 230001, Anhui Province, China
| | - Jie Ding
- Department of Ophthalmology, the Second People's Hospital of Hefei, Hefei 230001, Anhui Province, China
| | - Yuan-Ye Yan
- Department of Ophthalmology, Wannan Medical College, Wuhu 241001, Anhui Province, China
| | - Li Lu
- Department of Ophthalmology, Eye Center, the First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, Anhui Province, China
| | - Yi-Sai Wang
- Department of Ophthalmology, Anhui Provincial Hospital, Anhui Medical University, Hefei 230001, Anhui Province, China
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14
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Chan TC, Wilkinson Berka JL, Deliyanti D, Hunter D, Fung A, Liew G, White A. The role of reactive oxygen species in the pathogenesis and treatment of retinal diseases. Exp Eye Res 2020; 201:108255. [PMID: 32971094 DOI: 10.1016/j.exer.2020.108255] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/15/2022]
Abstract
Reactive oxygen species (ROS) normally play an important physiological role in health regulating cellular processes and signal transduction. The amount of ROS is usually kept in fine balance with the generation of ROS largely being offset by the body's antioxidants. A tipping of this balance has increasingly been recognised as a contributor to human disease. The retina, as a result of its cellular anatomy and physical location, is a potent generator of ROS that has been linked to several major retinal diseases. This review will provide a summary of the role of oxidative stress in the pathogenesis of diabetic retinopathy, age-related macular degeneration, myopia, retinal vein occlusion, retinitis pigmentosa and retinopathy of prematurity. Therapies aimed at controlling oxidative stress in these diseases are also examined.
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Affiliation(s)
- Thomas Cw Chan
- Discipline of Ophthalmology and Eye Health, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia
| | - Jennifer L Wilkinson Berka
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, The University of Melbourne, Medical Building 181, Grattan Street, Parkville, Victoria, 3010, Australia; Department of Diabetes, The Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
| | - Devy Deliyanti
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, The University of Melbourne, Medical Building 181, Grattan Street, Parkville, Victoria, 3010, Australia; Department of Diabetes, The Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
| | - Damien Hunter
- Discipline of Ophthalmology and Eye Health, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia; Centre for Vision Research, Westmead Institute of Medical Research, New South Wales, Australia
| | - Adrian Fung
- Westmead and Central Clinical Schools, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia; Faculty of Medicine Health and Human Sciences, Macquarie University, New South Wales, Australia; Save Sight Institute, 8 Macquarie St, Sydney, Australia
| | - Gerald Liew
- Discipline of Ophthalmology and Eye Health, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia; Centre for Vision Research, Westmead Institute of Medical Research, New South Wales, Australia
| | - Andrew White
- Discipline of Ophthalmology and Eye Health, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia; Centre for Vision Research, Westmead Institute of Medical Research, New South Wales, Australia; Save Sight Institute, 8 Macquarie St, Sydney, Australia; Personal Eyes, Level 6, 34 Charles St, Parramatta, 2150, Australia.
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15
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Iwagawa T, Aihara Y, Umutoni D, Baba Y, Murakami A, Miyado K, Watanabe S. Cd9 Protects Photoreceptors from Injury and Potentiates Edn2 Expression. Invest Ophthalmol Vis Sci 2020; 61:7. [PMID: 32150249 PMCID: PMC7401443 DOI: 10.1167/iovs.61.3.7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Purpose Cd9 is a tetraspanin membrane protein that plays various roles in tissue development and disease pathogenesis, especially in cancer, but the expression patterns and function of Cd9 in retinal development and disease are not well understood. We asked its roles during retinal photoreceptor degeneration by using CD9-knockout mice. Methods Cd9 knockout mice and rd1 mice were used to examine roles of Cd9 for progression of photoreceptor degeneration. Reverse transcription-polymerase chain reaction and immunohistochemistry were mainly used as analytical methods. Results Cd9 transcripts were only weakly expressed in retina at embryonic day 14, but its expression level subsequently increased and peaked at around postnatal day 12. In 6-week-old female mice derived retina, mRNA expression decreased slightly but was maintained at a significant level. Published RNA-sequencing data and immunohistochemistry indicated that Cd9 was expressed abundantly in Müller glia and weakly in other retinal neurons. Notably, when photoreceptors were damaged, Cd9 expression was increased in rod photoreceptors and decreased in Müller glia. Cd9 knockout mice retinas developed normally; however, once the retina suffered damage, degeneration of photoreceptors was more severe in Cd9 knockout retinas than control retinas. Induction of Edn2, which is known to protect against photoreceptor damage, was severely hampered. In addition, induction of Socs3, which is downstream of gp130 (Il6st), was weaker in Cd9 knockout retinas. Conclusions Taken together, these findings indicate that, although Cd9 was dispensable for normal gross morphological development, it protected rod photoreceptors and enhanced Edn2 expression, possibly through modulation of gp130 signaling.
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16
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Effects of an Aquaporin 4 Inhibitor, TGN-020, on Murine Diabetic Retina. Int J Mol Sci 2020; 21:ijms21072324. [PMID: 32230876 DOI: 10.3390/ijms21072324] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/20/2020] [Accepted: 03/26/2020] [Indexed: 12/13/2022] Open
Abstract
PURPOSE To investigate the effect of a selective aquaporin 4 (AQP4) inhibitor, 2-(nicotinamide)-1,3,4-thiadiazole (TGN-020), on the expression of vascular endothelial growth factor (VEGF) and reactive oxygen species (ROS) production, as well as on the retinal edema in diabetic retina. METHODS Intravitreal injections of bevacizumab, TGN-020, or phosphate-buffered saline (PBS) were performed on streptozotocin-induced diabetic rats. Retinal sections were immunostained for anti-glial fibrillary acidic protein (GFAP), anti-AQP4, and anti-VEGF. Protein levels of VEGF from collected retinas were determined by Western blot analysis. In addition, retinal vascular leakage of Evans Blue was observed in the flat-mounted retina from the diabetic rats in the presence or absence of TGN-020. Volumetric changes of rat retinal Müller cells (TR-MUL5; transgenic rat Müller cells) and intracellular levels of ROS were determined using flow cytometry analysis of ethidium fluorescence in the presence or absence of TGN-020 or bevacizumab under physiological and high glucose conditions. RESULTS In the diabetic retina, the immunoreactivity and protein levels of VEGF were suppressed by TGN-020. AQP4 immunoreactivity was higher than in the control retinas and the expressions of AQP4 were co-localized with GFAP. Similarly to VEGF, AQP4 and GFAP were also suppressed by TGN-020. In the Evans Blue assay, TGN-020 decreased leakage in the diabetic retinas. In the cultured Müller cells, the increase in cell volumes and intracellular ROS production under high glucose condition were suppressed by exposure to TGN-020 as much as by exposure to bevacizumab. CONCLUSION TGN-020 may have an inhibitory effect on diabetic retinal edema.
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17
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Barrera-Chimal J, Jaisser F. Vascular mineralocorticoid receptor activation and disease. Exp Eye Res 2019; 188:107796. [PMID: 31521629 DOI: 10.1016/j.exer.2019.107796] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 09/09/2019] [Accepted: 09/10/2019] [Indexed: 12/11/2022]
Abstract
Mineralocorticoid receptor activation in endothelial and smooth muscle cells can promote vascular disease by increasing oxidative stress, promoting inflammation, accelerating vascular stiffness, remodeling, and calcification, altering vessel responsiveness to various vasoactive factors, thus altering vascular tone and blood pressure, and by altering angiogenesis. Here, we review the recent evidence highlighting the impact of vascular mineralocorticoid receptor activation in pathological situations, including kidney injury, vascular injury associated with metabolic diseases, atherosclerosis, cerebral vascular injury during hypertension, vascular stiffening and aging, pulmonary hypertension, vascular calcification, cardiac remodeling, wound healing, inflammation, thrombosis, and disorders related to angiogenic defects in the eye. The possible mechanisms implicating mineralocorticoid receptor activation in various vascular disorders are discussed. Altogether, recent evidence points towards pharmacological mineralocorticoid receptor inhibition as a strategy to treat diseases in which overactivation of the mineralocorticoid receptor in endothelial and/or smooth muscle cells may play a pivotal role.
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Affiliation(s)
- Jonatan Barrera-Chimal
- Laboratorio de Fisiología Cardiovascular y Trasplante Renal, Unidad de Medicina Traslacional, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Frederic Jaisser
- INSERM U1116, Clinical Investigation Centre, Lorraine University, Vandoeuvre-lès-Nancy, France; INI-CRCT (Cardiovascular and Renal Clinical Trialists) F-CRIN Network, Nancy, France; Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, USPC, Université Paris Descartes, Université Paris Diderot, F-75006, Paris, France.
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18
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Alrashdi SF, Deliyanti D, Wilkinson-Berka JL. Intravitreal administration of endothelin type A receptor or endothelin type B receptor antagonists attenuates hypertensive and diabetic retinopathy in rats. Exp Eye Res 2018; 176:1-9. [PMID: 29944850 DOI: 10.1016/j.exer.2018.06.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/25/2018] [Accepted: 06/22/2018] [Indexed: 12/17/2022]
Abstract
Hypertension is an independent risk factor for diabetic retinopathy, yet anti-hypertensive medications such as blockade of angiotensin II do not completely protect against vision-threatening vascular disease. We hypothesized that the potent vasoactive factor, endothelin (ET), is up-regulated in diabetic retinopathy and antagonism of the ET type A receptor (ETRA) or ET type B receptor (ETRB) ameliorates retinal vascular leakage independently of any blood pressure lowering effects. Spontaneously hypertensive rats (SHR) and their normotensive and genetic controls, Wistar Kyoto rats, were randomized to become diabetic or non-diabetic and studied for 8 weeks. Rats were further randomized to receive by intravitreal injection the ETRA antagonist, BQ123, the ETRB antagonist, BQ788, or vehicle, 5 days after the induction of streptozotocin diabetes and 4 weeks later. The treatments had no effect on systolic blood pressure which remained elevated in SHR. ET-1, ET-2, ETRA and ETRB were expressed in retina and retinal pigment epithelium (RPE)/choroid and increased by hypertension or diabetes. BQ123 reduced ET-1 and ET-2 expression in retina and RPE/choroid, while BQ788 had a similar effect but did not influence the mRNA levels of ET-1 in retina. Retinal vascular leakage and Müller cell stress as well as vascular endothelial growth factor (VEGF) expression in retina and RPE/choroid, were increased by hypertension or diabetes and there was an additive effect of these conditions. Treatment with BQ123 or BQ788 effectively reduced these events as well as the elevated levels of inflammatory factors in the retina. Our findings indicate that local ET systems exist in the retina and RPE/choroid that are up-regulated by hypertension and diabetes. The ability of locally delivered ET receptor antagonists to supress these overactive ET systems and reduce retinal vascular leakage and VEGF in the presence of hypertension indicate the potential of these approaches for the treatment of diabetic retinopathy.
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Affiliation(s)
- Saeed F Alrashdi
- Department of Diabetes, The Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Devy Deliyanti
- Department of Diabetes, The Central Clinical School, Monash University, Melbourne, Victoria, Australia
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