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Alarcon-Martinez L, Shiga Y, Villafranca-Baughman D, Cueva Vargas JL, Vidal Paredes IA, Quintero H, Fortune B, Danesh-Meyer H, Di Polo A. Neurovascular dysfunction in glaucoma. Prog Retin Eye Res 2023; 97:101217. [PMID: 37778617 DOI: 10.1016/j.preteyeres.2023.101217] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/23/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
Retinal ganglion cells, the neurons that die in glaucoma, are endowed with a high metabolism requiring optimal provision of oxygen and nutrients to sustain their activity. The timely regulation of blood flow is, therefore, essential to supply firing neurons in active areas with the oxygen and glucose they need for energy. Many glaucoma patients suffer from vascular deficits including reduced blood flow, impaired autoregulation, neurovascular coupling dysfunction, and blood-retina/brain-barrier breakdown. These processes are tightly regulated by a community of cells known as the neurovascular unit comprising neurons, endothelial cells, pericytes, Müller cells, astrocytes, and microglia. In this review, the neurovascular unit takes center stage as we examine the ability of its members to regulate neurovascular interactions and how their function might be altered during glaucomatous stress. Pericytes receive special attention based on recent data demonstrating their key role in the regulation of neurovascular coupling in physiological and pathological conditions. Of particular interest is the discovery and characterization of tunneling nanotubes, thin actin-based conduits that connect distal pericytes, which play essential roles in the complex spatial and temporal distribution of blood within the retinal capillary network. We discuss cellular and molecular mechanisms of neurovascular interactions and their pathophysiological implications, while highlighting opportunities to develop strategies for vascular protection and regeneration to improve functional outcomes in glaucoma.
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Affiliation(s)
- Luis Alarcon-Martinez
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada; Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia
| | - Yukihiro Shiga
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Deborah Villafranca-Baughman
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Jorge L Cueva Vargas
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Isaac A Vidal Paredes
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Heberto Quintero
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Healthy, Portland, OR, USA
| | - Helen Danesh-Meyer
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, New Zealand
| | - Adriana Di Polo
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada.
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Lindner T, Schmidl D, Peschorn L, Pai V, Popa-Cherecheanu A, Chua J, Schmetterer L, Garhöfer G. Therapeutic Potential of Cannabinoids in Glaucoma. Pharmaceuticals (Basel) 2023; 16:1149. [PMID: 37631064 PMCID: PMC10460067 DOI: 10.3390/ph16081149] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 08/07/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023] Open
Abstract
Glaucoma is a leading cause of irreversible blindness worldwide. To date, intraocular pressure (IOP) is the only modifiable risk factor in glaucoma treatment, but even in treated patients, the disease can progress. Cannabinoids, which have been known to lower IOP since the 1970s, have been shown to have beneficial effects in glaucoma patients beyond their IOP-lowering properties. In addition to the classical cannabinoid receptors CB1 and CB2, knowledge of non-classical cannabinoid receptors and the endocannabinoid system has increased in recent years. In particular, the CB2 receptor has been shown to mediate anti-inflammatory, anti-apoptotic, and neuroprotective properties, which may represent a promising therapeutic target for neuroprotection in glaucoma patients. Due to their vasodilatory effects, cannabinoids improve blood flow to the optic nerve head, which may suggest a vasoprotective potential and counteract the altered blood flow observed in glaucoma patients. The aim of this review was to assess the available evidence on the effects and therapeutic potential of cannabinoids in glaucoma patients. The pharmacological mechanisms underlying the effects of cannabinoids on IOP, neuroprotection, and ocular hemodynamics have been discussed.
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Affiliation(s)
- Theresa Lindner
- Department of Clinical Pharmacology, Medical University Vienna, 1090 Vienna, Austria; (T.L.); (D.S.); (L.P.); (V.P.); (L.S.)
| | - Doreen Schmidl
- Department of Clinical Pharmacology, Medical University Vienna, 1090 Vienna, Austria; (T.L.); (D.S.); (L.P.); (V.P.); (L.S.)
| | - Laura Peschorn
- Department of Clinical Pharmacology, Medical University Vienna, 1090 Vienna, Austria; (T.L.); (D.S.); (L.P.); (V.P.); (L.S.)
| | - Viktoria Pai
- Department of Clinical Pharmacology, Medical University Vienna, 1090 Vienna, Austria; (T.L.); (D.S.); (L.P.); (V.P.); (L.S.)
| | - Alina Popa-Cherecheanu
- Department of Ophthalmology, Emergency University Hospital, 050098 Bucharest, Romania;
- Carol Davila University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Jacqueline Chua
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 169856, Singapore;
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Leopold Schmetterer
- Department of Clinical Pharmacology, Medical University Vienna, 1090 Vienna, Austria; (T.L.); (D.S.); (L.P.); (V.P.); (L.S.)
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 169856, Singapore;
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), Nanyang Technological University, Singapore 639798, Singapore
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637459, Singapore
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, 1090 Vienna, Austria
- Institute of Molecular and Clinical Ophthalmology, 4031 Basel, Switzerland
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology, Medical University Vienna, 1090 Vienna, Austria; (T.L.); (D.S.); (L.P.); (V.P.); (L.S.)
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Nordahl KML, Fedulov V, Holm A, Haanes KA. Intraocular Adeno-Associated Virus-Mediated Transgene Endothelin-1 Delivery to the Rat Eye Induces Functional Changes Indicative of Retinal Ischemia-A Potential Chronic Glaucoma Model. Cells 2023; 12:1987. [PMID: 37566067 PMCID: PMC10417058 DOI: 10.3390/cells12151987] [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: 05/26/2023] [Revised: 07/19/2023] [Accepted: 07/25/2023] [Indexed: 08/12/2023] Open
Abstract
Endothelin-1 (ET-1) overactivity has been implicated as a factor contributing to glaucomatous neuropathy, and it has been utilized in animal models of retinal ischemia. The functional effects of long-term ET-1 exposure and possible compensatory mechanisms have, however, not been investigated. This was therefore the purpose of our study. ET-1 was delivered into rat eyes via a single intravitreal injection of 500 µM or via transgene delivery using an adeno-associated viral (AAV) vector. Retinal function was assessed using electroretinography (ERG) and the retinal expression of potentially compensatory genes was evaluated by means of qRT-PCR. Acute ET-1 delivery led to vasoconstriction and a significant reduction in the ERG response. AAV-ET-1 resulted in substantial transgene expression and ERG results similar to the acute ET-1 injections and comparable to other models of retinal ischemia. Compensatory changes were observed, including an increase in calcitonin gene-related peptide (CGRP) gene expression, which may both counterbalance the vasoconstrictive effects of ET-1 and provide neuroprotection. This chronic ET-1 ischemia model might be especially relevant to glaucoma research, mimicking the mild and repeated ischemic events in patients with long-term vascular dysfunction. The compensatory mechanisms, and particularly the role of vasodilatory CGRP in mitigating the retinal damage, warrant further investigation with the aim of evaluating new therapeutic strategies.
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Affiliation(s)
- Karin M. L. Nordahl
- Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, 2600 Glostrup, Denmark; (A.H.); (K.A.H.)
| | - Vadim Fedulov
- Clinical and Medical Affairs, Radiometer, 2700 Brønshøj, Denmark;
| | - Anja Holm
- Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, 2600 Glostrup, Denmark; (A.H.); (K.A.H.)
- Center for RNA Medicine, Department of Clinical Medicine, Aalborg University, 2450 Copenhagen, Denmark
| | - Kristian A. Haanes
- Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, 2600 Glostrup, Denmark; (A.H.); (K.A.H.)
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Lakshmanan Y, Wong FSY, Chan HHL. Long-Term Effects on Retinal Structure and Function in a Mouse Endothelin-1 Model of Retinal Ganglion Cell Degeneration. Invest Ophthalmol Vis Sci 2023; 64:15. [PMID: 37561449 PMCID: PMC10424801 DOI: 10.1167/iovs.64.11.15] [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: 04/18/2023] [Accepted: 07/22/2023] [Indexed: 08/11/2023] Open
Abstract
Purpose To study the long-term effects of endothelin-1 (ET-1)-induced retinal pathologies in mouse, using clinically relevant tools. Methods Adult C57BL/6 mice (7-9 weeks old) were intravitreally injected with PBS (n = 10) or 0.25 (n = 8), 0.5 (n = 8), or 1 nmol ET-1 (n = 9) and examined using electroretinogram, optical coherence tomography (OCT), and Doppler OCT at baseline and postinjection days 10, 28, and 56. Retinal ganglion cell (RGC) survival in retinal whole mount was quantified at days 28 and 56. Results ET-1 induced immediate retinal arterial constriction. The significantly reduced total blood flow and positive scotopic threshold response in the 0.5- and 1-nmol ET-1 groups at day 10 were recovered at day 28. A-wave magnitude was also significantly reduced at days 10 and 28. While a comparable and significant reduction in retinal nerve fiber layer thickness was detected in all ET-1 groups at day 56, the 1-nmol group was the earliest to develop such change at day 28. All ET-1 groups showed a transient inner retinal layer thinning at days 10 and 28 and a plateaued outer layer thickness at days 10 to 56. The 1-nmol group showed a significant RGC loss over all retinal locations examined at day 28 as compared with PBS control. As for the lower-dosage groups, significant RGC density loss at central and midperipheral retina was detected at day 56 when compared with day 28. Conclusions ET-1 injection in mice resulted in a transient vascular constriction and reduction in retinal functions, as well as a gradual loss of retinal nerve fiber layer and RGC in a dose-dependent manner.
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Affiliation(s)
| | | | - Henry Ho-Lung Chan
- Centre for Eye and Vision Research (CEVR), Hong Kong, Hong Kong
- Laboratory of Experimental Optometry (Neuroscience), School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong SAR, China
- University Research Facilities in Behavioral and Systems Neuroscience (UBSN), The Hong Kong Polytechnic University, Hong Kong SAR, China
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5
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Kodati B, Zhang W, He S, Pham JH, Beall KJ, Swanger ZE, Krishnamoorthy VR, Harris PE, Hall T, Tran AV, Chaphalkar RM, Chavala SH, Stankowska DL, Krishnamoorthy RR. The endothelin receptor antagonist macitentan ameliorates endothelin-mediated vasoconstriction and promotes the survival of retinal ganglion cells in rats. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1185755. [PMID: 38464735 PMCID: PMC10921982 DOI: 10.3389/fopht.2023.1185755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Glaucoma is a chronic and progressive eye disease, commonly associated with elevated intraocular pressure (IOP) and characterized by optic nerve degeneration, cupping of the optic disc, and loss of retinal ganglion cells (RGCs). The pathological changes in glaucoma are triggered by multiple mechanisms and both mechanical effects and vascular factors are thought to contribute to the etiology of glaucoma. Various studies have shown that endothelin-1 (ET-1), a vasoactive peptide, acting through its G protein coupled receptors, ETA and ETB, plays a pathophysiologic role in glaucoma. However, the mechanisms by which ET-1 contribute to neurodegeneration remain to be completely understood. Our laboratory and others demonstrated that macitentan (MAC), a pan endothelin receptor antagonist, has neuroprotective effects in rodent models of IOP elevation. The current study aimed to determine if oral administration of a dual endothelin antagonist, macitentan, could promote neuroprotection in an acute model of intravitreal administration of ET-1. We demonstrate that vasoconstriction following the intravitreal administration of ET-1 was attenuated by dietary administration of the ETA/ETB dual receptor antagonist, macitentan (5 mg/kg body weight) in retired breeder Brown Norway rats. ET-1 intravitreal injection produced a 40% loss of RGCs, which was significantly lower in macitentan-treated rats. We also evaluated the expression levels of glial fibrillary acidic protein (GFAP) at 24 h and 7 days post intravitreal administration of ET-1 in Brown Norway rats as well as following ET-1 treatment in cultured human optic nerve head astrocytes. We observed that at the 24 h time point the expression levels of GFAP was upregulated (indicative of glial activation) following intravitreal ET-1 administration in both retina and optic nerve head regions. However, following macitentan administration for 7 days after intravitreal ET-1 administration, we observed an upregulation of GFAP expression, compared to untreated rats injected intravitreally with ET-1 alone. Macitentan treatment in ET-1 administered rats showed protection of RGC somas but was not able to preserve axonal integrity and functionality. The endothelin receptor antagonist, macitentan, has neuroprotective effects in the retinas of Brown Norway rats acting through different mechanisms, including enhancement of RGC survival and reduction of ET-1 mediated vasoconstriction.
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Affiliation(s)
- Bindu Kodati
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, United States
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Wei Zhang
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, United States
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Shaoqing He
- Department of Pathology, Children’s Health at Dallas, Dallas, TX, United States
| | - Jennifer H. Pham
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, United States
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Kallen J. Beall
- Department of General Surgery, Honor Health, Phoenix, AZ, United States
| | - Zoe E. Swanger
- Texas College of Osteopathic Medicine, University of North Texas Health Science Center, Fort Worth, TX, United States
| | | | - Payton E. Harris
- Department of Graduate Medical Education, Medical City, Fort Worth, TX, United States
| | - Trent Hall
- Williams College, Williamstown, MA, United States
| | - Ashley V. Tran
- School of Natural Sciences and Mathematics, The University of Texas at Dallas, Richardson, TX, United States
| | - Renuka M. Chaphalkar
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, United States
| | - Sai H. Chavala
- Department of Surgery, Burnett School of Medicine at Texas Christian University (TCU), Fort Worth, TX, United States
| | - Dorota L. Stankowska
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, United States
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Raghu R. Krishnamoorthy
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, United States
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, United States
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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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Enhanced Physiological Stress Response in Patients with Normal Tension Glaucoma during Hypoxia. J Ophthalmol 2021; 2021:5826361. [PMID: 34430053 PMCID: PMC8049796 DOI: 10.1155/2021/5826361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 03/17/2021] [Accepted: 03/25/2021] [Indexed: 11/17/2022] Open
Abstract
Purpose To investigate whether patients with normal tension glaucoma (NTG) show an enhanced stress response to reduced oxygen supply compared to age-matched healthy controls, measured by serum adrenaline and endothelin-1 (ET-1) levels and changes in distal finger temperature. Methods A thorough clinical characterization of patients with NTG and age-matched controls was performed prior to inclusion in the study. Twelve patients with NTG and eleven healthy controls met the inclusion criteria and were enrolled in the study. All subjects underwent a two-day investigation. Participants were randomly exposed to either hypoxia or normoxia during the first visit. Hypoxia or normoxia was induced for two hours through a tightly fitting face mask. In addition, the peripheral circulation was assessed with a thermographic camera. Blood samples were obtained before, during, and after hypoxia or normoxia to evaluate systemic stress molecules such as catecholamines and ET-1 levels. Results In patients with NTG, reduced oxygen supply induced an increase in peripheral blood adrenaline (p < 0.05) and a decrease during recovery (p < 0.01). A difference in distal finger temperature was shown in patients with NTG under hypoxia compared to normoxia (exposure: p < 0.05; recovery: p < 0.05). Hypoxia induced an increase in peripheral blood ET-1 levels in both groups (NTG: p < 0.01; controls: p < 0.05). Conclusion Patients with NTG had an enhanced physiological stress response as a consequence of hypoxia compared with age-matched controls. Although more studies are needed, the present study supports the involvement of vascular risk factors in the pathophysiology of NTG.
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Kodati B, Stankowska DL, Krishnamoorthy VR, Krishnamoorthy RR. Involvement of c-Jun N-terminal kinase 2 (JNK2) in Endothelin-1 (ET-1) Mediated Neurodegeneration of Retinal Ganglion Cells. Invest Ophthalmol Vis Sci 2021; 62:13. [PMID: 33978676 PMCID: PMC8131991 DOI: 10.1167/iovs.62.6.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Purpose The goal of this study was to determine whether JNK2 played a causative role in endothelin-mediated loss of RGCs in mice. Methods JNK2−/− and wild type (C57BL/6) mice were intravitreally injected in one eye with 1 nmole of ET-1, whereas the contralateral eye was injected with the vehicle. At two time points (two hours and 24 hours) after the intravitreal injections, mice were euthanized, and phosphorylated c-Jun was assessed in retinal sections. In a separate set of experiments, JNK2−/− and wild type mice were intravitreally injected with either 1 nmole of ET-1 or its vehicle and euthanized seven days after injection. Retinal flat mounts were stained with antibodies to the RGC marker, Brn3a, and surviving RGCs were quantified. Axonal degeneration was assessed in paraphenylenediamine stained optic nerve sections. Results Intravitreal ET-1 administration produced a significant increase in immunostaining for phospho c-Jun in wild type mice, which was appreciably lower in the JNK2 −/− mice. A significant (P < 0.05) 26% loss of RGCs was found in wild type mice, seven days after injection with ET-1. JNK2−/− mice showed a significant protection from RGC loss following ET-1 administration, compared to wild type mice injected with ET-1. A significant decrease in axonal counts and an increase in the collapsed axons was found in ET-1 injected wild type mice eyes. Conclusions JNK2 appears to play a major role in ET-1 mediated loss of RGCs in mice. Neuroprotective effects in JNK2−/− mice following ET-1 administration occur mainly in the soma and not in the axons of RGCs.
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Affiliation(s)
- Bindu Kodati
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, United States.,North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Dorota L Stankowska
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, United States.,North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Vignesh R Krishnamoorthy
- Department of Cellular and Molecular Physiology, Loyola University, Maywood, Illinois, United States
| | - Raghu R Krishnamoorthy
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, United States.,North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
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Izumiya Y, Okuda Y, Ueki S, Takeda M, Sato K, Nakayama K. Unusual morphologies of blood eosinophils in GM-CSF-producing lung cancer. QJM 2021; 114:42-44. [PMID: 32343814 DOI: 10.1093/qjmed/hcaa144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Indexed: 11/13/2022] Open
Affiliation(s)
- Y Izumiya
- Department of Respiratory Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - Y Okuda
- Department of Respiratory Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - S Ueki
- Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - M Takeda
- Department of Respiratory Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - K Sato
- Department of Respiratory Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - K Nakayama
- Department of Respiratory Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
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Kamiya T, Omae T, Nakabayashi S, Takahashi K, Tanner A, Yoshida A. Effect of Rho Kinase Inhibitor Ripasudil (K-115) on Isolated Porcine Retinal Arterioles. J Ocul Pharmacol Ther 2020; 37:104-111. [PMID: 33351704 DOI: 10.1089/jop.2020.0082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Purpose: To investigate the vasorelaxation effect of ripasudil (K-115), a novel Rho-associated coiled-coil-containing protein kinase (ROCK) inhibitor, on isolated retinal arterioles. We determined whether the actions of ripasudil on the retinal microvascular diameter were dependent on the endothelium and/or potassium channels in the smooth muscle, with the goals of uncovering the signaling mechanisms required for this vasomotor activity and inhibiting the action of endothelin-1 (ET-1). Methods: In this in vitro study, we isolated porcine retinal arterioles, which were cannulated and pressurized without flow. We recorded diametric changes using videomicroscopic techniques. Results: In a dose-dependent (10 nM-30 μM) manner, retinal arterioles were relaxed in response to ripasudil [maximum % resting diameter, 160.3% ± 7.7% (mean ± standard error of the mean)]. The ripasudil-induced vasorelaxation was unaffected by endothelium removal, using nonselective potassium channel blocker tetraethylammonium, Ca2+-activated large-conductance potassium channel blocker iberiotoxin, voltage-gated potassium channel blocker 4-AP, ATP-sensitive potassium channel blocker glibenclamide, and inward rectifier potassium channel blocker BaCl2. Ripasudil prevented ET-1-caused vasoconstriction of the retinal arterioles regardless of the presence of endothelium to a similar extent. Conclusion: The ROCK inhibitor ripasudil elicits endothelium-independent relaxation and inhibits the action of ET-1 on the retinal arterioles. Determining the relaxation properties of ripasudil on the retinal microvasculature will likely support the development of potential therapies for glaucoma.
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Affiliation(s)
- Takayuki Kamiya
- Department of Ophthalmology, Asahikawa Medical University, Asahikawa, Japan
| | - Tsuneaki Omae
- Department of Ophthalmology, Asahikawa Medical University, Asahikawa, Japan
| | - Seigo Nakabayashi
- Department of Ophthalmology, Asahikawa Medical University, Asahikawa, Japan
| | - Kengo Takahashi
- Department of Ophthalmology, Asahikawa Medical University, Asahikawa, Japan
| | - Akira Tanner
- Department of Ophthalmology, Asahikawa Medical University, Asahikawa, Japan
| | - Akitoshi Yoshida
- Department of Ophthalmology, Asahikawa Medical University, Asahikawa, Japan
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11
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Baudouin C, Kolko M, Melik-Parsadaniantz S, Messmer EM. Inflammation in Glaucoma: From the back to the front of the eye, and beyond. Prog Retin Eye Res 2020; 83:100916. [PMID: 33075485 DOI: 10.1016/j.preteyeres.2020.100916] [Citation(s) in RCA: 168] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 10/09/2020] [Accepted: 10/13/2020] [Indexed: 02/08/2023]
Abstract
The pathophysiology of glaucoma is complex, multifactorial and not completely understood. Elevated intraocular pressure (IOP) and/or impaired retinal blood flow may cause initial optic nerve damage. In addition, age-related oxidative stress in the retina concurrently with chronic mechanical and vascular stress is crucial for the initiation of retinal neurodegeneration. Oxidative stress is closely related to cell senescence, mitochondrial dysfunction, excitotoxicity, and neuroinflammation, which are involved in glaucoma progression. Accumulating evidence from animal glaucoma models and from human ocular samples suggests a dysfunction of the para-inflammation in the retinal ganglion cell layer and the optic nerve head. Moreover, quite similar mechanisms in the anterior chamber could explain the trabecular meshwork dysfunction and the elevated IOP in primary open-angle glaucoma. On the other hand, ocular surface disease due to topical interventions is the most prominent and visible consequence of inflammation in glaucoma, with a negative impact on filtering surgery failure, topical treatment efficacy, and possibly on inflammation in the anterior segment. Consequently, glaucoma appears as an outstanding eye disease where inflammatory changes may be present to various extents and consequences along the eye structure, from the ocular surface to the posterior segment, and the visual pathway. Here we reviewed the inflammatory processes in all ocular structures in glaucoma from the back to the front of the eye and beyond. Our approach was to explain how para-inflammation is necessary to maintain homoeostasis, and to describe abnormal inflammatory findings observed in glaucomatous patients or in animal glaucoma models, supporting the hypothesis of a dysregulation of the inflammatory balance toward a pro-inflammatory phenotype. Possible anti-inflammatory therapeutic approaches in glaucoma are also discussed.
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Affiliation(s)
- Christophe Baudouin
- Quinze-Vingts National Ophthalmology Hospital, INSERM-DGOS CIC 1423, IHU Foresight, Paris, France; Sorbonne Université, INSERM, CNRS, Institut de La Vision, Paris, France; Department of Ophthalmology, Ambroise Paré Hospital, APHP, Université de Versailles Saint-Quentin en Yvelines, Boulogne-Billancourt, France.
| | - Miriam Kolko
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark; Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet-Glostrup, Glostrup, Denmark
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Marola OJ, Syc-Mazurek SB, Howell GR, Libby RT. Endothelin 1-induced retinal ganglion cell death is largely mediated by JUN activation. Cell Death Dis 2020; 11:811. [PMID: 32980857 PMCID: PMC7519907 DOI: 10.1038/s41419-020-02990-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 08/26/2020] [Accepted: 08/27/2020] [Indexed: 01/02/2023]
Abstract
Glaucoma is a neurodegenerative disease characterized by loss of retinal ganglion cells (RGCs), the output neurons of the retina. Multiple lines of evidence show the endothelin (EDN, also known as ET) system is important in glaucomatous neurodegeneration. To date, the molecular mechanisms within RGCs driving EDN-induced RGC death have not been clarified. The pro-apoptotic transcription factor JUN (the canonical target of JNK signaling) and the endoplasmic reticulum stress effector and transcription factor DNA damage inducible transcript 3 (DDIT3, also known as CHOP) have been shown to act downstream of EDN receptors. Previous studies demonstrated that JUN and DDIT3 were important regulators of RGC death after glaucoma-relevant injures. Here, we characterized EDN insult in vivo and investigated the role of JUN and DDIT3 in EDN-induced RGC death. To accomplish this, EDN1 ligand was intravitreally injected into the eyes of wildtype, Six3-cre+Junfl/fl (Jun-/-), Ddit3 null (Ddit3-/-), and Ddit3-/-Jun-/- mice. Intravitreal EDN1 was sufficient to drive RGC death in vivo. EDN1 insult caused JUN activation in RGCs, and deletion of Jun from the neural retina attenuated RGC death after EDN insult. However, deletion of Ddit3 did not confer significant protection to RGCs after EDN1 insult. These results indicate that EDN caused RGC death via a JUN-dependent mechanism. In addition, EDN signaling is known to elicit potent vasoconstriction. JUN signaling was shown to drive neuronal death after ischemic insult. Therefore, the effects of intravitreal EDN1 on retinal vessel diameter and hypoxia were explored. Intravitreal EDN1 caused transient retinal vasoconstriction and regions of RGC and Müller glia hypoxia. Thus, it remains a possibility that EDN elicits a hypoxic insult to RGCs, causing apoptosis via JNK-JUN signaling. The importance of EDN-induced vasoconstriction and hypoxia in causing RGC death after EDN insult and in models of glaucoma requires further investigation.
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Affiliation(s)
- Olivia J. Marola
- grid.412750.50000 0004 1936 9166Department of Ophthalmology, Flaum Eye Institute, University of Rochester Medical Center, Rochester, NY USA ,grid.412750.50000 0004 1936 9166Cell Biology of Disease Graduate Program, University of Rochester Medical Center, Rochester, NY USA ,grid.16416.340000 0004 1936 9174The Center for Visual Sciences, University of Rochester, Rochester, NY USA
| | - Stephanie B. Syc-Mazurek
- grid.412750.50000 0004 1936 9166Department of Ophthalmology, Flaum Eye Institute, University of Rochester Medical Center, Rochester, NY USA ,grid.412750.50000 0004 1936 9166Medical Scientist Training Program, University of Rochester Medical Center, Rochester, NY USA
| | - Gareth R. Howell
- grid.249880.f0000 0004 0374 0039The Jackson Laboratory, 600 Main Street, Bar Harbor, ME USA
| | - Richard T. Libby
- grid.412750.50000 0004 1936 9166Department of Ophthalmology, Flaum Eye Institute, University of Rochester Medical Center, Rochester, NY USA ,grid.16416.340000 0004 1936 9174The Center for Visual Sciences, University of Rochester, Rochester, NY USA ,grid.412750.50000 0004 1936 9166Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY USA
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13
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Wareham LK, Calkins DJ. The Neurovascular Unit in Glaucomatous Neurodegeneration. Front Cell Dev Biol 2020; 8:452. [PMID: 32656207 PMCID: PMC7325980 DOI: 10.3389/fcell.2020.00452] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/15/2020] [Indexed: 12/31/2022] Open
Abstract
Glaucoma is a neurodegenerative disease of the visual system and leading cause of blindness worldwide. The disease is associated with sensitivity to intraocular pressure (IOP), which over a large range of magnitudes stresses retinal ganglion cell (RGC) axons as they pass through the optic nerve head in forming the optic projection to the brain. Despite clinical efforts to lower IOP, which is the only modifiable risk factor for glaucoma, RGC degeneration and ensuing loss of vision often persist. A major contributor to failure of hypotensive regimens is the multifactorial nature of how IOP-dependent stress influences RGC physiology and structure. This stress is conveyed to the RGC axon through interactions with structural, glial, and vascular components in the nerve head and retina. These interactions promote pro-degenerative pathways involving biomechanical, metabolic, oxidative, inflammatory, immunological and vascular challenges to the microenvironment of the ganglion cell and its axon. Here, we focus on the contribution of vascular dysfunction and breakdown of neurovascular coupling in glaucoma. The vascular networks of the retina and optic nerve head have evolved complex mechanisms that help to maintain a continuous blood flow and supply of metabolites despite fluctuations in ocular perfusion pressure. In healthy tissue, autoregulation and neurovascular coupling enable blood flow to stay tightly controlled. In glaucoma patients evidence suggests these pathways are dysfunctional, thus highlighting a potential role for pathways involved in vascular dysfunction in progression and as targets for novel therapeutic intervention.
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Affiliation(s)
- Lauren K Wareham
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
| | - David J Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
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Chesnokova NB, Pavlenko TA, Beznos OV, Grigoryev AV. [The role of the endothelin system in the pathogenesis of eye diseases]. Vestn Oftalmol 2020; 136:117-123. [PMID: 32241978 DOI: 10.17116/oftalma2020136011117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The endothelin system (ES) plays a complex role in the pathogenesis of various eye diseases as a local regulator of vascular tone as well as many other physiological processes. Components of ES - endothelins and their receptors - can be found nearly in all cellular structures of the eye, their concentration increases in the presence of many eye diseases. In glaucoma, ES is involved in the mechanisms of eye hypertension by influencing the secretion and outflow of aqueous humor. The increase of endothelin level leads to the decrease of perfusion pressure, hypoxia, astrocyte proliferation, increase of density and rigidity of lamina cribrosa, apoptosis of neural cells, and has a profibrogenic effect. In retinal pathology, increase of endothelins disturbs autoregulation of retinal blood vessels changing the neurovascular interactions, breaks intercellular contacts in the retina, promotes neoangiogenesis. In diabetic retinopathy, ES contributes to the development of microangiopathy and proliferative vitreoretinopathy. The review discusses the possibility of correcting ES activity in the eye with medications by influencing its synthesis, cleavage and receptor binding.
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Affiliation(s)
- N B Chesnokova
- Helmholtz National Medical Research Center of Eye Diseases, 14/19 Sadovaya-Chernogryazskaya St., Moscow, Russian Federation, 105062
| | - T A Pavlenko
- Helmholtz National Medical Research Center of Eye Diseases, 14/19 Sadovaya-Chernogryazskaya St., Moscow, Russian Federation, 105062
| | - O V Beznos
- Helmholtz National Medical Research Center of Eye Diseases, 14/19 Sadovaya-Chernogryazskaya St., Moscow, Russian Federation, 105062
| | - A V Grigoryev
- Helmholtz National Medical Research Center of Eye Diseases, 14/19 Sadovaya-Chernogryazskaya St., Moscow, Russian Federation, 105062
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15
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Endothelin-1 Mediated Decrease in Mitochondrial Gene Expression and Bioenergetics Contribute to Neurodegeneration of Retinal Ganglion Cells. Sci Rep 2020; 10:3571. [PMID: 32107448 PMCID: PMC7046667 DOI: 10.1038/s41598-020-60558-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 02/07/2020] [Indexed: 11/09/2022] Open
Abstract
Endothelin-1 (ET-1) is a vasoactive peptide that is elevated in aqueous humor as well as circulation of primary open angle glaucoma (POAG) patients. ET-1 has been shown to promote degeneration of optic nerve axons and apoptosis of retinal ganglion cells (RGCs), however, the precise mechanisms are still largely unknown. In this study, RNA-seq analysis was used to assess changes in ET-1 mediated gene expression in primary RGCs, which revealed that 23 out of 156 differentially expressed genes (DEGs) had known or predicted mitochondrial function, of which oxidative phosphorylation emerged as the top-most enriched pathway. ET-1 treatment significantly decreased protein expression of key mitochondrial genes including cytochrome C oxidase copper chaperone (COX17) and ATP Synthase, H+ transporting, Mitochondrial Fo Complex (ATP5H) in primary RGCs and in vivo following intravitreal ET-1 injection in rats. A Seahorse ATP rate assay revealed a significant decrease in the rate of mitochondrial ATP production following ET-1 treatment. IOP elevation in Brown Norway rats showed a trend towards decreased expression of ATP5H. Our results demonstrate that ET-1 produced a decrease in expression of vital components of mitochondrial electron transport chain, which compromise bioenergetics and suggest a mechanism by which ET-1 promotes neurodegeneration of RGCs in glaucoma.
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16
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Lakshmanan Y, Wong FSY, Zuo B, So KF, Bui BV, Chan HHL. Posttreatment Intervention With Lycium Barbarum Polysaccharides is Neuroprotective in a Rat Model of Chronic Ocular Hypertension. Invest Ophthalmol Vis Sci 2020; 60:4606-4618. [PMID: 31756254 DOI: 10.1167/iovs.19-27886] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate the neuroprotective effects of Lycium barbarum polysaccharides (LBP) against chronic ocular hypertension (OHT) in rats and to consider if effects differed when treatment was applied before (pretreatment) or during (posttreatment) chronic IOP elevation. Methods Sprague-Dawley rats (10-weeks old) underwent suture implantation around the limbus for 15 weeks (OHT) or 1 day (sham). Four experimental groups were studied, three OHT groups (n = 8 each) treated either with vehicle (PBS), LBP pretreatment or posttreatment, and a sham control (n = 5) received no treatment. LBP (1 mg/kg) pre- and posttreatment were commenced at 1 week before and 4 weeks after OHT induction, respectively. Treatments continued up through week 15. IOP was monitored twice weekly for 15 weeks. Optical coherence tomography and ERG were measured at baseline, week 4, 8, 12, and 15. Eyes were collected for ganglion cell layer (GCL) histologic analysis at week 15. Results Suture implantation successfully induced approximately 50% IOP elevation and the cumulative IOP was similar between the three OHT groups. When compared with vehicle control (week 4: -23 ± 5%, P = 0.03), LBP pretreatment delayed the onset of retinal nerve fiber layer (RNFL) thinning (week 4, 8: -2 ± 7%, -11 ± 3%, P > 0.05) and arrested further reduction up through week 15 (-10 ± 4%, P > 0.05). LBP posttreatment intervention showed no significant change in rate of loss (week 4, 15: -25 ± 4.1%, -28 ± 3%). However, both LBP treatments preserved the retinal ganglion cells (RGC) and retinal functions up to week 15, which were significantly reduced in vehicle control. Conclusions LBP posttreatment arrested the subsequent neuronal degeneration after treatment commencement and preserved RGC density and retinal functions in a chronic OHT model, which was comparable with pretreatment outcomes.
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Affiliation(s)
- Yamunadevi Lakshmanan
- Laboratory of Experimental Optometry (Neuroscience), School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Francisca Siu Yin Wong
- Laboratory of Experimental Optometry (Neuroscience), School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Bing Zuo
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Kwok-Fai So
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.,Guangdong-Hongkong-Macau (GHM) Institute of CNS Regeneration, Jinan University, Guangzhou, China
| | - Bang Viet Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, Australia
| | - Henry Ho-Lung Chan
- Laboratory of Experimental Optometry (Neuroscience), School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China.,Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China
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17
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Inducible rodent models of glaucoma. Prog Retin Eye Res 2019; 75:100799. [PMID: 31557521 DOI: 10.1016/j.preteyeres.2019.100799] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 09/16/2019] [Accepted: 09/18/2019] [Indexed: 11/23/2022]
Abstract
Glaucoma is one of the leading causes of vision impairment worldwide. In order to further understand the molecular pathobiology of this disease and to develop better therapies, clinically relevant animal models are necessary. In recent years, both the rat and mouse have become popular models in glaucoma research. Key reasons are: many important biological similarities shared among rodent eyes and the human eye; development of improved methods to induce glaucoma and to evaluate glaucomatous damage; availability of genetic tools in the mouse; as well as the relatively low cost of rodent studies. Commonly studied rat and mouse glaucoma models include intraocular pressure (IOP)-dependent and pressure-independent models. The pressure-dependent models address the most important risk factor of elevated IOP, whereas the pressure-independent models assess "normal tension" glaucoma and other "non-IOP" related factors associated with glaucomatous damage. The current article provides descriptions of these models, their characterizations, specific techniques to induce glaucoma, mechanisms of injury, advantages, and limitations.
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18
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Kiseleva TN, Chudin AV, Khoroshilova-Maslova IP, Shchipanova AI, Maibogin AM, Zaitsev MS. Morphological Changes in the Retina Under Conditions of Experimental In Vivo Regional Ischemia/Reperfusion. Bull Exp Biol Med 2019; 167:287-292. [PMID: 31243673 DOI: 10.1007/s10517-019-04511-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Indexed: 11/28/2022]
Abstract
Two models of retinal ischemia/reperfusion were developed in an experiment on rats and structural changes in eye tissues in the early and late postischemic periods were studied. Ischemia/reperfusion was modeled by elevation of intraocular pressure to 110 mm Hg for 30 min with air injection into the anterior chamber of the eye with a special device or subconjunctival administration of 0.2 ml 4×10-6 M endothelin-1. Morphological studies of the retina of enucleated eyes were performed in 3, 7, and 30 days after ischemia/reperfusion. In 3 days, signs of retinal ischemia were seen (retinal edema and ganglion cell damage). In the late post-ischemic period (30 days), atrophy of the outer nuclear and outer plexiform layer of the retina was observed in animals with retinal ischemia/reperfusion caused by intraocular pressure elevation and complete destruction of neuronal cells was found after administration of endothelin-1.
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Affiliation(s)
- T N Kiseleva
- Helmholtz Moscow Research Institute of Eye Diseases, Ministry of Health of the Russian Federation, Moscow, Russia.
| | - A V Chudin
- Helmholtz Moscow Research Institute of Eye Diseases, Ministry of Health of the Russian Federation, Moscow, Russia
| | - I P Khoroshilova-Maslova
- Helmholtz Moscow Research Institute of Eye Diseases, Ministry of Health of the Russian Federation, Moscow, Russia
| | - A I Shchipanova
- Helmholtz Moscow Research Institute of Eye Diseases, Ministry of Health of the Russian Federation, Moscow, Russia
| | - A M Maibogin
- Helmholtz Moscow Research Institute of Eye Diseases, Ministry of Health of the Russian Federation, Moscow, Russia
| | - M S Zaitsev
- Helmholtz Moscow Research Institute of Eye Diseases, Ministry of Health of the Russian Federation, Moscow, Russia
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Villena A, Díaz F, Vidal L, Moreno M, Garcĺa-Campos J, De Vargas IP. Study of the effects of ocular hypotensive drugs on number of neurons in the retinal ganglion layer in a rat experimental glaucoma. Eur J Ophthalmol 2018; 19:963-70. [DOI: 10.1177/112067210901900611] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Alicia Villena
- Department of Histology and Histopathology, School of Medicine, University of Málaga
| | - Florentina Díaz
- Department of Histology and Histopathology, School of Medicine, University of Málaga
| | - Lourdes Vidal
- Department of Histology and Histopathology, School of Medicine, University of Málaga
| | - Mercedes Moreno
- Department of Ophthalmology, School of Medicine, University of Málaga - Spain
| | - Jose Garcĺa-Campos
- Department of Ophthalmology, School of Medicine, University of Málaga - Spain
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20
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He S, Stankowska DL, Ellis DZ, Krishnamoorthy RR, Yorio T. Targets of Neuroprotection in Glaucoma. J Ocul Pharmacol Ther 2017; 34:85-106. [PMID: 28820649 DOI: 10.1089/jop.2017.0041] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Progressive neurodegeneration of the optic nerve and the loss of retinal ganglion cells is a hallmark of glaucoma, the leading cause of irreversible blindness worldwide, with primary open-angle glaucoma (POAG) being the most frequent form of glaucoma in the Western world. While some genetic mutations have been identified for some glaucomas, those associated with POAG are limited and for most POAG patients, the etiology is still unclear. Unfortunately, treatment of this neurodegenerative disease and other retinal degenerative diseases is lacking. For POAG, most of the treatments focus on reducing aqueous humor formation, enhancing uveoscleral or conventional outflow, or lowering intraocular pressure through surgical means. These efforts, in some cases, do not always lead to a prevention of vision loss and therefore other strategies are needed to reduce or reverse the progressive neurodegeneration. In this review, we will highlight some of the ocular pharmacological approaches that are being tested to reduce neurodegeneration and provide some form of neuroprotection.
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Affiliation(s)
- Shaoqing He
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
| | - Dorota L Stankowska
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
| | - Dorette Z Ellis
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
| | - Raghu R Krishnamoorthy
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
| | - Thomas Yorio
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
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21
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Blanco R, Martínez-Navarrete G, Valiente-Soriano FJ, Avilés-Trigueros M, Pérez-Rico C, Serrano-Puebla A, Boya P, Fernández E, Vidal-Sanz M, de la Villa P. The S1P1 receptor-selective agonist CYM-5442 protects retinal ganglion cells in endothelin-1 induced retinal ganglion cell loss. Exp Eye Res 2017; 164:37-45. [PMID: 28827028 DOI: 10.1016/j.exer.2017.08.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 07/09/2017] [Accepted: 08/03/2017] [Indexed: 11/16/2022]
Abstract
We investigated the feasibility and efficacy of using a specific sphingosine 1-phosphate (S1P1) receptor agonist, CYM-5442, to slow or block retinal ganglion cell (RGC) loss in endothelin-1 (ET-1) induced RGC loss. A single intravitreal injection of ET-1 (20pmol/ul), a potent vasoactive peptide that produces retinal vessels vasoconstriction, was used to induce and characterize RGC-specific cell death. CYM-5442 (1 mgr/kg) or vehicle was administered intraperitoneally for five consecutive days after ET-1-induced RGC loss. The functional extent of RGC loss injury was evaluated with pattern visual evoked potentials (VEP) and electroretinography. RGCs and retinal nerve fiber layer (RNFL) thickness were assessed in vivo using optical coherence tomography and ex vivo using Brn3a immunohistochemistry in flat-mounted retinas. ET-1 caused significant RGC loss and function loss one week after intravitreal injection. VEP showed preserved visual function after CYM-5442 administration compared to vehicle-treated animals (11.95 ± 0.86 μV vs 3.47 ± 1.20 μV, n = 12) (p < 0.05). RNFL was significantly thicker in the CYM treated-animals compared to the vehicle (93.62 ± 3.22 μm vs 77.72 ± 0.35 μm, n = 12) (p < 0.05). Furthermore, Brn3a immunohistochemistry validated this observation, showing significantly higher RGCs numbers in CYM treated rats than in the vehicle group (76,540 ± 303 vs 52,426 ± 1,932 cells/retina, n = 9) (p = 0.05). CYM-5442 administration was associated with significant retinal cleaved caspase-3 deactivation, indicating reduced apoptotic levels. The results of the present study further demonstrate the important role of S1P1 receptor agonists to lessen intravitreal ET-1 induced RGC loss.
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Affiliation(s)
- Román Blanco
- Department of Surgery, Medical and Social Sciences, University of Alcalá, Alcalá de Henares, Madrid, Spain.
| | - Gema Martínez-Navarrete
- Institute of Bioengineering, Miguel Hernandez University, Elche, Alicante, Spain; Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Spain
| | - Francisco J Valiente-Soriano
- Department of Ophthalmology, University of Murcia and Murcia Institute of Biosanitary Research Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Marcelino Avilés-Trigueros
- Department of Ophthalmology, University of Murcia and Murcia Institute of Biosanitary Research Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Consuelo Pérez-Rico
- Department of Surgery, Medical and Social Sciences, University of Alcalá, Alcalá de Henares, Madrid, Spain; Department of Ophthalmology, Principe de Asturias University Hospital, Alcalá de Henares, Madrid, Spain
| | - Ana Serrano-Puebla
- Department of Cellular and Molecular Biology, Biological Research Center, CSIC, Madrid, Spain
| | - Patricia Boya
- Department of Cellular and Molecular Biology, Biological Research Center, CSIC, Madrid, Spain
| | - Eduardo Fernández
- Institute of Bioengineering, Miguel Hernandez University, Elche, Alicante, Spain; Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Spain
| | - Manuel Vidal-Sanz
- Department of Ophthalmology, University of Murcia and Murcia Institute of Biosanitary Research Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Pedro de la Villa
- Department of Systems Biology, University of Alcalá, Alcalá de Henares, Madrid, Spain
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Mihaylova B, Petkova I, Rankova-Yotova C, Dimitrova G, Tanev I, Ivanova S, Tsakova A, Svinarov D. Plasma endothelin-1 and endothelin-A receptor concentrations in patients with primary open-angle glaucoma. BIOTECHNOL BIOTEC EQ 2017. [DOI: 10.1080/13102818.2017.1334592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Affiliation(s)
- Bilyana Mihaylova
- Department of Ophthalmology, University Hospital ‘Alexandrovska’, Medical University of Sofia, Sofia, Bulgaria
| | - Iva Petkova
- Department of Ophthalmology, University Hospital ‘Alexandrovska’, Medical University of Sofia, Sofia, Bulgaria
| | - Charita Rankova-Yotova
- Department of Ophthalmology, University Hospital ‘Alexandrovska’, Medical University of Sofia, Sofia, Bulgaria
| | - Galina Dimitrova
- Department of Ophthalmology, University Hospital ‘Alexandrovska’, Medical University of Sofia, Sofia, Bulgaria
| | - Ivan Tanev
- Department of Ophthalmology, University Hospital ‘Alexandrovska’, Medical University of Sofia, Sofia, Bulgaria
| | - Stanislava Ivanova
- Department of Ophthalmology, University Hospital ‘Alexandrovska’, Medical University of Sofia, Sofia, Bulgaria
| | - Adelina Tsakova
- Department of Clinical Laboratory & Clinical Immunology, University Hospital ‘Alexandrovska’, Medical University of Sofia, Sofia, Bulgaria
| | - Dobrin Svinarov
- Department of Clinical Laboratory & Clinical Immunology, University Hospital ‘Alexandrovska’, Medical University of Sofia, Sofia, Bulgaria
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23
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McGrady NR, Minton AZ, Stankowska DL, He S, Jefferies HB, Krishnamoorthy RR. Upregulation of the endothelin A (ET A) receptor and its association with neurodegeneration in a rodent model of glaucoma. BMC Neurosci 2017; 18:27. [PMID: 28249604 PMCID: PMC5333388 DOI: 10.1186/s12868-017-0346-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 02/16/2017] [Indexed: 01/24/2023] Open
Abstract
Background Primary open angle glaucoma is a heterogeneous group of optic neuropathies that results in optic nerve degeneration and a loss of retinal ganglion cells (RGCs) ultimately causing blindness if allowed to progress. Elevation of intraocular pressure (IOP) is the most attributable risk factor for developing glaucoma and lowering of IOP is currently the only available therapy. However, despite lowering IOP, neurodegenerative effects persist in some patients. Hence, it would be beneficial to develop approaches to promote neuroprotection of RGCs in addition to IOP lowering therapies. The endothelin system is a key target for intervention against glaucomatous neurodegeneration. The endothelin family of peptides and receptors, particularly endothelin-1 (ET-1) and endothelin B (ETB) receptor, has been shown to have neurodegenerative roles in glaucoma. The purpose of this study was to examine changes in endothelin A (ETA) receptor protein expression in the retinas of adult male Brown Norway rats following IOP elevation by the Morrison’s model of ocular hypertension and the impact of ETA receptor overexpression on RGC viability in vitro. Results IOP elevation was carried out in one eye of Brown Norway rats by injection of hypertonic saline through episcleral veins. After 2 weeks of IOP elevation, immunohistochemical analysis of retinal sections from rat eyes showed an increasing trend in immunostaining for ETA receptors in multiple retinal layers including the inner plexiform layer, ganglion cell layer and outer plexiform layer. Following 4 weeks of IOP elevation, a significant increase in immunostaining for ETA receptor expression was found in the retina, primarily in the inner plexiform layer and ganglion cells. A modest increase in staining for ETA receptors was also found in the outer plexiform layer in the retina of rats with IOP elevation. Cell culture studies showed that overexpression of ETA receptors in 661W cells as well as primary RGCs decreases cell viability, compared to empty vector transfected cells. Adeno-associated virus mediated overexpression of the ETA receptor produced an increase in the ETB receptor in primary RGCs. Conclusions Elevated IOP results in an appreciable change in ETA receptor expression in the retina. Overexpression of the ETA receptor results in an overall decrease in cell viability, accompanied by an increase in ETB receptor levels, suggesting the involvement of both ETA and ETB receptors in mediating cell death. These findings raise possibilities for the development of ETA/ETB dual receptor antagonists as neuroprotective treatments for glaucomatous neuropathy. Electronic supplementary material The online version of this article (doi:10.1186/s12868-017-0346-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nolan R McGrady
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Alena Z Minton
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Dorota L Stankowska
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Shaoqing He
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Hayden B Jefferies
- Texas College of Osteopathic Medicine, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Raghu R Krishnamoorthy
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA.
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Protective effect of magnesium acetyltaurate against endothelin-induced retinal and optic nerve injury. Neuroscience 2016; 325:153-64. [PMID: 27012609 DOI: 10.1016/j.neuroscience.2016.03.041] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/14/2016] [Accepted: 03/15/2016] [Indexed: 12/27/2022]
Abstract
Vascular dysregulation has long been recognized as an important pathophysiological factor underlying the development of glaucomatous neuropathy. Endothelin-1 (ET1) has been shown to be a key player due to its potent vasoconstrictive properties that result in retinal ischemia and oxidative stress leading to retinal ganglion cell (RGC) apoptosis and optic nerve (ON) damage. In this study we investigated the protective effects of magnesium acetyltaurate (MgAT) against retinal cell apoptosis and ON damage. MgAT was administered intravitreally prior to, along with or after administration of ET1. Seven days post-injection, animals were euthanized and retinae were subjected to morphometric analysis, TUNEL and caspase-3 staining. ON sections were stained with toluidine blue and were graded for neurodegenerative effects. Oxidative stress was also estimated in isolated retinae. Pre-treatment with MgAT significantly lowered ET1-induced retinal cell apoptosis as measured by retinal morphometry and TUNEL staining. This group of animals also showed significantly lesser caspase-3 activation and significantly reduced retinal oxidative stress compared to the animals that received intravitreal injection of only ET1. Additionally, the axonal degeneration in ON was markedly reduced in MgAT pretreated animals. The animals that received MgAT co- or post-treatment with ET1 also showed improvement in all parameters; however, the effects were not as significant as observed in MgAT pretreated animals. The current study showed that the intravitreal pre-treatment with MgAT reduces caspase-3 activation and prevents retinal cell apoptosis and axon loss in ON induced by ET1. This protective effect of ET1 was associated with reduced retinal oxidative stress.
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Sappington RM, Sidorova T, Ward NJ, Chakravarthy R, Ho KW, Calkins DJ. Activation of transient receptor potential vanilloid-1 (TRPV1) influences how retinal ganglion cell neurons respond to pressure-related stress. Channels (Austin) 2016; 9:102-13. [PMID: 25713995 DOI: 10.1080/19336950.2015.1009272] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Our recent studies implicate the transient receptor potential vanilloid-1 (TRPV1) channel as a mediator of retinal ganglion cell (RGC) function and survival. With elevated pressure in the eye, TRPV1 increases in RGCs, supporting enhanced excitability, while Trpv1 -/- accelerates RGC degeneration in mice. Here we find TRPV1 localized in monkey and human RGCs, similar to rodents. Expression increases in RGCs exposed to acute changes in pressure. In retinal explants, contrary to our animal studies, both Trpv1 -/- and pharmacological antagonism of the channel prevented pressure-induced RGC apoptosis, as did chelation of extracellular Ca(2+). Finally, while TRPV1 and TRPV4 co-localize in some RGC bodies and form a protein complex in the retina, expression of their mRNA is inversely related with increasing ocular pressure. We propose that TRPV1 activation by pressure-related insult in the eye initiates changes in expression that contribute to a Ca(2+)-dependent adaptive response to maintain excitatory signaling in RGCs.
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Affiliation(s)
- Rebecca M Sappington
- a The Vanderbilt Eye Institute and Vanderbilt Brain Institute ; Vanderbilt University School of Medicine ; Nashville , TN USA
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26
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Abstract
Glaucoma is a progressive optic neuropathy that causes characteristic changes of the optic nerve and visual field in relation to intraocular pressure (IOP). It is now known that glaucoma can occur at statistically normal IOPs and prevalence studies have shown that normal tension glaucoma (NTG) is more common than previously thought. While IOP is believed to be the predominant risk factor in primary open angle glaucoma (POAG), IOP-independent risk factors, such as vascular dysregulation, are believed to play an important part in the pathogenesis of NTG. Though certain distinguishing phenotypic features of NTG have been reported, such as an increased frequency of disc hemorrhages, acquired pits of the optic nerve and characteristic patterns of disc cupping and visual field loss, there is much overlap of the clinical findings in NTG with POAG, suggesting that NTG is likely part of a continuum of open angle glaucomas. However, IOP modification is still the mainstay of treatment in NTG. As in traditional POAG, reduction of IOP can be achieved with the use of medications, laser trabeculoplasty or surgery. Studies now show that the choice of medication may also be important in determining the outcomes of these patients. Though it is likely that future treatment of NTG will involve modification of both IOP and IOP-independent risk factors, current efforts to develop IOP-independent neuroprotective treatments have not yet proven to be effective in humans.
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Affiliation(s)
| | - Joseph Caprioli
- Jules Stein Eye Institute, Department of Ophthalmology, University of California, Los Angeles, USA
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Vohra R, Tsai JC, Kolko M. The role of inflammation in the pathogenesis of glaucoma. Surv Ophthalmol 2013; 58:311-20. [PMID: 23768921 DOI: 10.1016/j.survophthal.2012.08.010] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2011] [Revised: 08/19/2012] [Accepted: 08/21/2012] [Indexed: 10/26/2022]
Abstract
Glaucoma is an ocular disorder characterized by the progressive loss of retinal ganglion cells (RGC) and their axons. There are various hypotheses concerning the cause of RGC death. Previously, glaucoma was defined by high intraocular pressure (IOP); during the past decade, however, glaucoma specialists have acknowledged that elevated IOP is the most important risk factor for glaucoma, but does not define the disease. Other factors such as genetics, blood flow, and excitotoxicity are suggested as potential causal factors for progressive RGC death observed in glaucoma. We review recent studies elucidating a possible role of low-grade inflammation as a causal factor in the pathogenesis of glaucoma.
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Affiliation(s)
- Rupali Vohra
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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He S, Minton AZ, Ma HY, Stankowska DL, Sun X, Krishnamoorthy RR. Involvement of AP-1 and C/EBPβ in upregulation of endothelin B (ETB) receptor expression in a rodent model of glaucoma. PLoS One 2013; 8:e79183. [PMID: 24265756 PMCID: PMC3827153 DOI: 10.1371/journal.pone.0079183] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 09/23/2013] [Indexed: 12/31/2022] Open
Abstract
Previous studies showed that the endothelin B receptor (ETB) expression was upregulated and played a key role in neurodegeneration in rodent models of glaucoma. However, the mechanisms underlying upregulation of ETB receptor expression remain largely unknown. Using promoter-reporter assays, the 1258 bp upstream the human ETB promoter region was found to be essential for constitutive expression of ETB receptor gene in human non-pigmented ciliary epithelial cells (HNPE). The −300 to −1 bp and −1258 to −600 bp upstream promoter regions of the ETB receptor appeared to be the key binding regions for transcription factors. In addition, the crucial AP-1 binding site located at −615 to −624 bp upstream promoter was confirmed by luciferase assays and CHIP assays which were performed following overexpression of c-Jun in HNPE cells. Overexpression of either c-Jun or C/EBPβ enhanced the ETB receptor promoter activity, which was reflected in increased mRNA and protein levels of ETB receptor. Furthermore, knock-down of either c-Jun or C/EBPβ in HNPE cells was significantly correlated to decreased mRNA levels of both ETB and ETA receptor. These observations suggest that c-Jun and C/EBPβ are important for regulated expression of the ETB receptor in HNPE cells. In separate experiments, intraocular pressure (IOP) was elevated in one eye of Brown Norway rats while the corresponding contralateral eye served as control. Two weeks of IOP elevation produced increased expression of c-Jun and C/EBPβ in the retinal ganglion cell (RGC) layer from IOP-elevated eyes. The mRNA levels of c-Jun, ETA and ETB receptor were upregulated by 2.2-, 3.1- and 4.4-fold in RGC layers obtained by laser capture microdissection from retinas of eyes with elevated IOP, compared to those from contralateral eyes. Taken together, these data suggest that transcription factor AP-1 plays a key role in elevation of ETB receptor in a rodent model of ocular hypertension.
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Affiliation(s)
- Shaoqing He
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
- * E-mail:
| | - Alena Z. Minton
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Hai-Ying Ma
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Dorota L. Stankowska
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Xiangle Sun
- Department of Molecular Biology and Immunology, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Raghu R. Krishnamoorthy
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
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Aqueous vascular endothelial growth factor and endothelin-1 levels in branch retinal vein occlusion associated with normal tension glaucoma. J Glaucoma 2013; 22:104-9. [PMID: 21946550 DOI: 10.1097/ijg.0b013e3182312047] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To evaluate aqueous levels of vascular endothelial growth factor (VEGF) and endothelin-1 (ET-1) in patients with branch retinal vein occlusion (BRVO) with and without normal tension glaucoma (NTG), and to assess the therapeutic efficacy of intravitreal bevacizumab (IVB) in these patients. METHODS Sixteen eyes with NTG of 48 age and sex-matched eyes without NTG that had previously received IVB for BRVO were followed for 6 months. Aqueous VEGF and ET-1 levels were measured by enzyme-linked immunosorbent assay at the time of baseline IVB. Logarithm of the minimum angle of resolution best corrected visual acuity (BCVA) and central macular thickness (CMT) were measured at baseline and then at 1, 3, and 6 months postinjection. RESULTS The obstruction site of BRVO was closer to the optic disk in eyes with NTG compared with controls (P=0.001). Baseline BCVA, CMT, and VEGF levels were similar between the 2 groups. Baseline ET-1 levels were significantly higher in eyes with NTG than those without NTG (P=0.009). After IVB, there was a significant improvement in both BCVA and CMT at 6 months, irrespective of the presence of NTG. However, BCVA in the presence of NTG was significantly worse at 6 months compared with eyes without NTG even though CMT was similarly reduced in both groups (P=0.04). CONCLUSIONS Aqueous VEGF levels are similar in patients with BRVO with or without NTG, whereas aqueous ET-1 levels are elevated in the presence of NTG. Although IVB may be effective in the treatment of BRVO, the presence of NTG may limit visual recovery despite anatomic recovery of CMT.
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Munemasa Y, Kitaoka Y. Molecular mechanisms of retinal ganglion cell degeneration in glaucoma and future prospects for cell body and axonal protection. Front Cell Neurosci 2013; 6:60. [PMID: 23316132 PMCID: PMC3540394 DOI: 10.3389/fncel.2012.00060] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 12/06/2012] [Indexed: 12/20/2022] Open
Abstract
Glaucoma, which affects more than 70 million people worldwide, is a heterogeneous group of disorders with a resultant common denominator; optic neuropathy, eventually leading to irreversible blindness. The clinical manifestations of primary open-angle glaucoma (POAG), the most common subtype of glaucoma, include excavation of the optic disc and progressive loss of visual field. Axonal degeneration of retinal ganglion cells (RGCs) and apoptotic death of their cell bodies are observed in glaucoma, in which the reduction of intraocular pressure (IOP) is known to slow progression of the disease. A pattern of localized retinal nerve fiber layer (RNFL) defects in glaucoma patients indicates that axonal degeneration may precede RGC body death in this condition. The mechanisms of degeneration of neuronal cell bodies and their axons may differ. In this review, we addressed the molecular mechanisms of cell body death and axonal degeneration in glaucoma and proposed axonal protection in addition to cell body protection. The concept of axonal protection may become a new therapeutic strategy to prevent further axonal degeneration or revive dying axons in patients with preperimetric glaucoma. Further study will be needed to clarify whether the combination therapy of axonal protection and cell body protection will have greater protective effects in early or progressive glaucomatous optic neuropathy (GON).
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Affiliation(s)
- Yasunari Munemasa
- Department of Ophthalmology, St. Marianna University School of Medicine Kawasaki, Kanagawa, Japan
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31
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Kim JM, Kim YJ, Kim DM. Increased expression of oxyproteins in the optic nerve head of an in vivo model of optic nerve ischemia. BMC Ophthalmol 2012; 12:63. [PMID: 23216747 PMCID: PMC3541215 DOI: 10.1186/1471-2415-12-63] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 11/27/2012] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND To investigate the effects of microvascular compromise on the expression of oxidative proteins in the optic nerve head. METHODS Endothelin-1 (0.1 μg/day) was delivered to the perineural region of the anterior optic nerve by osmotically driven minipumps for two, four, and eight weeks in ten rabbits, respectively. As a control, a balanced salt solution was delivered for two and eight weeks in five rabbits, respectively. Expression of oxyproteins in the cornea, vitreous, retina, and optic nerve head for each time period was determined using the OxyBlot protein oxidation detection kit. Retina was stained with H&E and TUNEL for histological examination. RESULTS There was a significant increase in the expression of oxyproteins in the optic nerve head after two weeks of endothelin-1 administration (p < 0.001, Mann Whitney U test). In contrast, there was no expression of oxyproteins in the cornea, retina, or vitreous. The number of cells in the retinal ganglion cell layer, inner nuclear layer, and outer nuclear layer decreased remarkably with time in the endothelin-1-treated group. Furthermore, the inner and outer nuclear layers, as well as the inner and outer plexiform layers, became thinner over time. CONCLUSIONS Administration of endothelin-1 to the microvasculature of the optic nerve leads to increased expression of oxyproteins in the optic nerve head and loss of retinal ganglion cells.
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Affiliation(s)
- Joon Mo Kim
- Department of Ophthalmology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Yu Jeong Kim
- Seoul National University Hospital Clinical Research Institute, Seoul, Korea
| | - Dong Myung Kim
- Department of Ophthalmology, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-Gu, Seoul, 110-744, Korea
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Minton AZ, Phatak NR, Stankowska DL, He S, Ma HY, Mueller BH, Jiang M, Luedtke R, Yang S, Brownlee C, Krishnamoorthy RR. Endothelin B receptors contribute to retinal ganglion cell loss in a rat model of glaucoma. PLoS One 2012; 7:e43199. [PMID: 22916224 PMCID: PMC3423444 DOI: 10.1371/journal.pone.0043199] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 07/18/2012] [Indexed: 12/29/2022] Open
Abstract
Glaucoma is an optic neuropathy, commonly associated with elevated intraocular pressure (IOP) characterized by optic nerve degeneration, cupping of the optic disc, and loss of retinal ganglion cells which could lead to loss of vision. Endothelin-1 (ET-1) is a 21-amino acid vasoactive peptide that plays a key role in the pathogenesis of glaucoma; however, the receptors mediating these effects have not been defined. In the current study, endothelin B (ETB) receptor expression was assessed in vivo, in the Morrison's ocular hypertension model of glaucoma in rats. Elevation of IOP in Brown Norway rats produced increased expression of ETB receptors in the retina, mainly in retinal ganglion cells (RGCs), nerve fiber layer (NFL), and also in the inner plexiform layer (IPL) and inner nuclear layer (INL). To determine the role of ETB receptors in neurodegeneration, Wistar-Kyoto wild type (WT) and ETB receptor-deficient (KO) rats were subjected to retrograde labeling with Fluoro-Gold (FG), following which IOP was elevated in one eye while the contralateral eye served as control. IOP elevation for 4 weeks in WT rats caused an appreciable loss of RGCs, which was significantly attenuated in KO rats. In addition, degenerative changes in the optic nerve were greatly reduced in KO rats compared to those in WT rats. Taken together, elevated intraocular pressure mediated increase in ETB receptor expression and its activation may contribute to a decrease in RGC survival as seen in glaucoma. These findings raise the possibility of using endothelin receptor antagonists as neuroprotective agents for the treatment of glaucoma.
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Affiliation(s)
- Alena Z. Minton
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Nitasha R. Phatak
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Dorota L. Stankowska
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Shaoqing He
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Hai-Ying Ma
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Brett H. Mueller
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Ming Jiang
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Robert Luedtke
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Shaohua Yang
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Colby Brownlee
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Raghu R. Krishnamoorthy
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
- * E-mail:
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Selective over-expression of endothelin-1 in endothelial cells exacerbates inner retinal edema and neuronal death in ischemic retina. PLoS One 2011; 6:e26184. [PMID: 22053184 PMCID: PMC3203861 DOI: 10.1371/journal.pone.0026184] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 09/22/2011] [Indexed: 11/19/2022] Open
Abstract
The level of endothelin-1 (ET-1), a potent vasoconstrictor, was associated with retinopathy under ischemia. The effects of endothelial endothelin-1 (ET-1) over-expression in a transgenic mouse model using Tie-1 promoter (TET-1 mice) on pathophysiological changes of retinal ischemia were investigated by intraluminal insertion of a microfilament up to middle cerebral artery (MCA) to transiently block the ophthalmic artery. Two-hour occlusion and twenty-two-hour reperfusion were performed in homozygous (Hm) TET-1 mice and their non-transgenic (NTg) littermates. Presence of pyknotic nuclei in ganglion cell layer (GCL) was investigated in paraffin sections of ipsilateral (ischemic) and contralateral (non-ischemic) retinae, followed by measurement of the thickness of inner retinal layer. Moreover, immunocytochemistry of glial fibrillary acidic protein (GFAP), glutamine synthetase (GS) and aquaporin-4 (AQP4) peptides on retinal sections were performed to study glial cell reactivity, glutamate metabolism and water accumulation, respectively after retinal ischemia. Similar morphology was observed in the contralateral retinae of NTg and Hm TET-1 mice, whereas ipsilateral retina of NTg mice showed slight structural and cellular changes compared with the corresponding contralateral retina. Ipsilateral retinae of Hm TET-1 mice showed more significant changes when compared with ipsilateral retina of NTg mice, including more prominent cell death in GCL characterized by the presence of pyknotic nuclei, elevated GS immunoreactivity in Müller cell bodies and processes, increased AQP-4 immunoreactivity in Müller cell processes, and increased inner retinal thickness. Thus, over-expression of endothelial ET-1 in TET-1 mice may contribute to increased glutamate-induced neurotoxicity on neuronal cells and water accumulation in inner retina leading to edema.
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Shoshani YZ, Harris A, Shoja MM, Rusia D, Siesky B, Arieli Y, Wirostko B. Endothelin and Its Suspected Role in the Pathogenesis and Possible Treatment of Glaucoma. Curr Eye Res 2011; 37:1-11. [DOI: 10.3109/02713683.2011.622849] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Schmidl D, Garhofer G, Schmetterer L. The complex interaction between ocular perfusion pressure and ocular blood flow - relevance for glaucoma. Exp Eye Res 2010; 93:141-55. [PMID: 20868686 DOI: 10.1016/j.exer.2010.09.002] [Citation(s) in RCA: 178] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 09/02/2010] [Accepted: 09/02/2010] [Indexed: 01/29/2023]
Abstract
Glaucoma is an optic neuropathy of unknown origin. The most important risk factor for the disease is an increased intraocular pressure (IOP). Reducing IOP is associated with reduced progression in glaucoma. Several recent large scale trials have indicated that low ocular perfusion pressure (OPP) is a risk factor for the incidence, prevalence and progression of the disease. This is a strong indicator that vascular factors are involved in the pathogenesis of the disease, a hypothesis that was formulated 150 years ago. The relation between OPP and blood flow to the posterior pole of the eye is, however, complex, because of a phenomenon called autoregulation. Autoregulatory processes attempt to keep blood flow constant despite changes in OPP. Although autoregulation has been observed in many experiments in the ocular vasculature the mechanisms underlying the vasodilator and vasoconstrictor responses in face of changes in OPP remain largely unknown. There is, however, recent evidence that the human choroid regulates its blood flow better during changes in blood pressure induced by isometric exercise than during changes in IOP induced by a suction cup. This may have consequences for our understanding of glaucoma, because it indicates that blood flow regulation is strongly dependent not only on OPP, but also on the level of IOP itself. Indeed there is data indicating that reduction of IOP by pharmacological intervention improves optic nerve head blood flow regulation independently of an ocular vasodilator effect.
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Affiliation(s)
- Doreen Schmidl
- Department of Clinical Pharmacology, Medical University of Vienna, Austria
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Abstract
IMPORTANCE OF THE FIELD Glaucoma is the second leading cause of blindness worldwide. To date, treatment of glaucoma has focused on lowering intraocular pressure (IOP) though there are other mechanisms that might damage the optic nerve, leading to characteristic visual field loss. Endothelin, a potent vasoconstrictor, is believed to play a role in the pathogenesis of glaucomatous optic neuropathy. AREAS COVERED IN THIS REVIEW We review the evidence from the last 20 years exploring the action of endothelin in the eye, its association with the pathophysiology of glaucoma, as well as the potential therapeutic role of targeting the endothelin pathway to affect disease progression in glaucomatous eyes. WHAT THE READER WILL GAIN The goal of this paper is to inform readers about endothelin structure, actions, and role in ocular pathology, pharmacology, and potential areas of future research. TAKE HOME MESSAGE Overall, we believe that the body of evidence supports the following conclusions; i) endothelin is a potent vasoconstrictor that plays a role in ocular physiology, ii) endothelin may play a role in the pathophysiology of glaucoma and iii) modulation of the endothelin system with newly discovered potent antagonists holds promise in treating glaucoma through both pressure-dependent and pressure-independent pathways.
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Affiliation(s)
- Travis J Good
- University of Colorado, Denver School of Medicine, Rocky Mountain Lions Eye Institute, Department of Ophthalmology, 1675 Aurora Court, PO Box 6510 Mail Stop F-731, Aurora, CO 80045, USA
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Iwabe S, Lamas M, Vásquez Pélaez CG, Carrasco FG. Aqueous humor endothelin-1 (Et-1), vascular endothelial growth factor (VEGF) and cyclooxygenase-2 (COX-2) levels in Mexican glaucomatous patients. Curr Eye Res 2010; 35:287-94. [PMID: 20373895 DOI: 10.3109/02713680903545315] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To evaluate the concentration of endothelin-1, vascular endothelial growth factor, and cyclooxygenase-2 in aqueous humor from normal and glaucomatous human patients. MATERIAL AND METHODS Concentrations of these proteins were measured using ELISA kits in 83 patients (30 presenting for cataract surgery and 53 with glaucoma). RESULTS Endothelin-1, vascular endothelial growth factor, and cyclooxygenase-2 were detected in all samples. The ages of the patients with glaucoma (64.51 +/- 17.51 years) and cataracts subjects (59.30 +/- 19.15 years) were similar. The endothelin-1 concentration in cataracts patients (48.55 +/- 9.50 pg/ml) was statistically different when compared to endothelin-1 concentration in aqueous humor from primary open-angle glaucoma (107.94 +/- 12.20 pg/ml) and neovascular glaucoma (114.68 +/- 25.50 pg/ml) (p < 0.05). No statistical difference was observed in normal tension glaucoma group (69.14 +/- 52.80 pg/ml) (p > 0.05). Vascular endothelial growth factor concentration was higher in neovascular glaucoma (81.84 +/- 6.40 pg/ml), being the difference statistically significant when compared with the other groups (p < 0.0001). Cyclooxygenase-2 levels showed no statistical difference between cataract groups and any other glaucoma group (p > 0.05). No effect of age, gender, or previously medication of aqueous humor concentration of these proteins could be detected (p > 0.05). CONCLUSION In this study we observed increased levels of endothelin-1 in aqueous humor from patients with primary open-angle glaucoma and neovascular glaucoma, and increased levels of vascular endothelial growth factor only in neovascular glaucoma patients, raising a possible connection between endothelin-1 and vascular endothelial growth factor in the role of some types of glaucoma. Regarding cyclooxygenase-2 levels detected, perhaps indicate that low values of cyclooxygenase-2 are necessary for normal functions of the eye.
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Affiliation(s)
- Simone Iwabe
- Pharmacobiology Department, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav), Mexico City, Mexico
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Oku H, Fukuhara M, Kurimoto T, Okuno T, Sugiyama T, Ikeda T. Endothelin-1 (ET-1) is Increased in Rat Retina After Crushing Optic Nerve. Curr Eye Res 2009; 33:611-20. [DOI: 10.1080/02713680802213614] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Single-cell imaging of retinal ganglion cell apoptosis with a cell-penetrating, activatable peptide probe in an in vivo glaucoma model. Proc Natl Acad Sci U S A 2009; 106:9391-6. [PMID: 19458250 DOI: 10.1073/pnas.0812884106] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Molecular imaging probes have potential for in vivo identification of apoptosis and other intracellular processes. TcapQ, a cell-penetrating, near-infrared fluorescent peptide probe designed to be optically silent through intramolecular fluorescence quenching and activated by effector caspases, has been previously described and validated in vitro. Herein, using NMDA-induced apoptosis of retinal ganglion cells (RGCs), representing an in vivo rat model of glaucoma, we assessed the ability of TcapQ to image single-cell apoptosis through effector caspase activity. Following intravitreal injection, intracellular TcapQ activation occurred specifically in RGCs, identified individual apoptotic cells, showed a clear dose-response relationship with NMDA, and colocalized with TUNEL labeling in the retina. There was a significant diminution of probe activation following pretreatment with a specific inhibitor of caspase-3. Stereospecificity was also exhibited by the lack of intracellular fluorescence upon administration of the noncleavable isomer, dTcapQ. TcapQ has potential utility in detecting and monitoring single-cell apoptosis in glaucoma in vivo.
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Sappington RM, Sidorova T, Long DJ, Calkins DJ. TRPV1: contribution to retinal ganglion cell apoptosis and increased intracellular Ca2+ with exposure to hydrostatic pressure. Invest Ophthalmol Vis Sci 2008; 50:717-28. [PMID: 18952924 DOI: 10.1167/iovs.08-2321] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
PURPOSE Elevated hydrostatic pressure induces retinal ganglion cell (RGC) apoptosis in culture. The authors investigated whether the transient receptor potential vanilloid 1 (TRPV1) channel, which contributes to pressure sensing and Ca(2+)-dependent cell death in other systems, also contributes to pressure-induced RGC death and whether this contribution involves Ca(2+). METHODS trpv1 mRNA expression in RGCs was probed with the use of PCR and TRPV1 protein localization through immunocytochemistry. Subunit-specific antagonism (iodo-resiniferatoxin) and agonism (capsaicin) were used to probe how TRPV1 activation affects the survival of isolated RGCs at ambient and elevated hydrostatic pressure (+70 mm Hg). Finally, for RGCs under pressure, the authors tested whether EGTA chelation of Ca(2+) improves survival and whether, with the Ca(2+) dye Fluo-4 AM, TRPV1 contributes to increased intracellular Ca(2+). RESULTS RGCs express trpv1 mRNA, with robust TRPV1 protein localization to the cell body and axon. For isolated RGCs under pressure, TRPV1 antagonism increased cell density and reduced apoptosis to ambient levels (P <or= 0.05), whereas for RGCs at ambient pressure, TRPV1 agonism reduced density and increased apoptosis to levels for elevated pressure (P <or= 0.01). Chelation of extracellular Ca(2+) reduced RGC apoptosis at elevated pressure by nearly twofold (P <or= 0.01). Exposure to elevated hydrostatic pressure induced a fourfold increase in RGC intracellular Ca(2+) that was reduced by half with TRPV1 antagonism. Finally, in the DBA/2 mouse model of glaucoma, levels of TRPV1 in RGCs increased with elevated IOP. CONCLUSIONS RGC apoptosis induced by elevated hydrostatic pressure arises substantially through TRPV1, likely through the influx of extracellular Ca(2+).
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Affiliation(s)
- Rebecca M Sappington
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee 37232-0654, USA
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Krishnamoorthy RR, Rao VR, Dauphin R, Prasanna G, Johnson C, Yorio T. Role of the ETB receptor in retinal ganglion cell death in glaucoma. Can J Physiol Pharmacol 2008; 86:380-93. [PMID: 18516102 DOI: 10.1139/y08-040] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Recent observations suggest that the vasoactive peptide endothelin-1 (ET-1) may be an important contributor to the etiology of glaucoma. ET-1 administration has been shown to produce optic nerve axonal loss and apoptosis of retinal ganglion cells. Ocular ET-1 levels are elevated in aqueous humor in response to elevated intraocular pressure both in glaucoma patients and in animal models of glaucoma; however, the precise mechanisms by which ET-1 mediates glaucomatous optic neuropathy are not clear. Presently we report that ET-1-mediated apoptosis was markedly attenuated in ETB receptor-deficient rats, suggesting a key role for ETB receptors in apoptosis of retinal ganglion cells by ET-1 treatment. Using virally transformed rat retinal ganglion cells (RGC-5 cells), we found that ET-1 (100 nmol/L) treatment produced apoptotic changes in these cells that was determined by flow cytometric analyses, release of mitochondrial cytochrome c to the cytosol, and increased phosphorylation of c-Jun N-terminal kinase. Pretreatment with the ETB-receptor antagonist BQ788 (1 micromol/L) was able to significantly attenuate ET-1-mediated apoptosis in RGC-5 cells. ET-1-mediated apoptotic changes in RGC-5 cells were associated with ETB-receptor activation and were accompanied by a significant upregulation of ETB-receptor expression. These studies suggest that ocular ET-1 acts through ETB receptors to mediate apoptosis of retinal ganglion cells, a key event in glaucoma and related optic neuropathies.
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Affiliation(s)
- Raghu R Krishnamoorthy
- Department of Pharmacology and Neuroscience, UNT Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA.
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Effects of unoprostone on phosphorylated extracellular signal-regulated kinase expression in endothelin-1-induced retinal and optic nerve damage. Vis Neurosci 2008; 25:197-208. [PMID: 18442442 DOI: 10.1017/s095252380808053x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Endothelin-1 (ET-1), a potent vasoconstrictor peptide, has been implicated in the development of normal- and high-tension glaucoma. We investigated the effects of unoprostone on extracellular signal-regulated kinase (ERK) in ET-1-induced retinal ganglion cell (RGC) death and optic nerve injury. Our morphometric study showed that intravitreal injection of ET-1 led to cell loss in the RGC layer (RGCL) in 28 days. Western blot analysis showed decreased neurofilament (NF) protein in the optic nerve 28 days after ET-1 injection. In this in vivo model, increased phosphorylated ERK (p-ERK) was observed in the retina on 1 day and subsequently in the optic nerve from 7 days after ET-1 injection. Simultaneous injection of M1, as a metabolite of unoprostone, showed further increased p-ERK levels compared with ET-1 injection alone. Our morphometric study of flat-mount preparations stained with cresyl violet or retrograde labeling with a neuro-tracer and Western blot analysis of NF showed that inhibition of ERK phosphorylation led to acceleration of ET-1-induced RGC death and optic nerve damage. In addition, M1 significantly attenuated both RGC loss and the decrease in NF protein induced by ET-1. The protective effects of M1 were significantly inhibited by U0126, an ERK inhibitor. These results suggest that unoprostone has neuroprotective effects against ET-1-induced neuronal injury through ERK phosphorylation.
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Evaluation of the retina and optic nerve in a rat model of chronic glaucoma using in vivo manganese-enhanced magnetic resonance imaging. Neuroimage 2008; 40:1166-74. [DOI: 10.1016/j.neuroimage.2008.01.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 12/21/2007] [Accepted: 01/05/2008] [Indexed: 11/19/2022] Open
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Endothelin-1 mediated regulation of extracellular matrix collagens in cells of human lamina cribrosa. Exp Eye Res 2008; 86:886-94. [PMID: 18420197 DOI: 10.1016/j.exer.2008.03.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Revised: 01/11/2008] [Accepted: 03/05/2008] [Indexed: 11/21/2022]
Abstract
Endothelin-1 (ET-1), a potent vaso-active peptide, mediates extracellular matrix regulation resulting in an increase in collagen deposition in various cell types and tissues and has been proposed to play a key role in glaucoma pathology. The role of ET-1 in the regulation of extracellular matrix collagens at the level of optic nerve head is not known. In this study we have examined the role of ET-1 in extracellular matrix collagen regulation in primary cultures of human lamina cribrosa cells. Our hypothesis is that ET-1 increases remodeling of the ECM of cells of the lamina cribrosa. Such actions could contribute to the development of optic neuropathy. QPCR analysis revealed that ET-1 mediated an increase in mRNA levels of collagen type I alpha1 and collagen type VI alpha1 chains at all doses of ET-1 with a significant increase at 1nM and 10nM concentration in LC cells. A dose-dependent increase in collagen type I and type VI protein deposition and secretion was also observed by Western blot in response to ET-1 and was significant at 10nM and 100nM concentrations of ET-1. ET-1 increased the [3H] proline uptake in LC cells suggesting that ET-1 contributed to an increase in total collagen synthesis in LC cells. ET-1-mediated increase in collagen type I, type VI and total collagen synthesis was significantly blocked by the ET(A) receptor antagonist, BQ610, as well as with the ET(B) receptor antagonist, BQ788, suggesting the involvement of both receptor subtypes in ET-1 mediated collagen synthesis in LC cells. These results suggest that ET-1 regulates extracellular matrix collagen synthesis in LC cells and may contribute to ECM remodeling at the level of LC of POAG subjects who have elevated plasma and aqueous humor levels of endothelin-1.
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Li Q, Xue Y, Xiao G, Zhang J. New microscopic pushbroom hyperspectral imaging system for application in diabetic retinopathy research. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:064011. [PMID: 18163827 DOI: 10.1117/1.2821210] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
To aid ophthalmologists in determining the pathogenesis of diabetic retinopathy and in evaluating the effects of medication, a microscopic pushbroom hyperspectral imaging system is developed. 40 healthy Wistar rats of half gender are selected in this study. They are divided into three groups (six rats failed to be models). 10 normal rats as the normal control group, 12 diabetic rats without any treatment as the model control group, and another 12 diabetic rats treated with LCVS1001 as the LCVS1001 group. The microscopic hyperspectral image of each retina section is collected and processed. Some typical spectrum curves between 400 and 800 nm of the outer nuclear layer are extracted, and images at various wavelengths are analyzed. The results show that a small trough appears near 522.2 nm in the typical spectrum curve of the model control group, and the transmittance of it is higher than that of the normal control group. In addition, the spectrum of the LCVS1001 group changes gradually to the normal spectrum after treatment with LCVS1001. Our findings indicate that LCVS1001 has some therapeutic effect on the diabetic retinopathy of rats, and the microscopic pushbroom hyperspectral imaging system can be used to study the pathogenesis of diabetic retinopathy.
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Affiliation(s)
- Qingli Li
- East China Normal University, Information Science, No. 500, Dongchuan Rd., Shanghai, 200241 China.
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Stokely ME, Bhat MA, Koulen P. Microfluorimetry defines early axonal damage in a rat model of optic neuritis: a novel method targeting early CNS autoimmunity. J Neurosci Methods 2007; 166:217-28. [PMID: 17719649 DOI: 10.1016/j.jneumeth.2007.07.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 06/29/2007] [Accepted: 07/13/2007] [Indexed: 01/28/2023]
Abstract
Autoimmune optic neuritis is a common early manifestation of multiple sclerosis (MS), yet early therapeutic interventions for MS often have high ocular toxicity associated with increased risks for glaucoma, cataract, or retinopathy. This need to discover better early treatment options prompted our development of a sensitive and reliable means to quantify the broad range of pathologies that potentially develop very early in autoimmune optic neuritis. Tissue microfluorimetry was used to measure seven established markers for human MS pathology in normal and autoimmune optic nerves 13 days after antigen exposure, in a Brown Norway rat model of myelin oligodendrocyte glycoprotein (MOG) peptide (35-55)-induced autoimmune optic neuritis. Optic neuritis rats demonstrated early and significant pathologic changes in five established indices for neuroinflammation, immune infiltration, and demyelination that accurately modeled pathologies characteristic of MS. Two indices of MS-like axon damage advanced significantly within 13 days of antigen exposure. Fluorimetrically measured immunoreactivity (-ir) was significantly decreased for paranodin (PN, the requisite axonal paranodal junction protein) and significantly increased for amyloid precursor protein (APP), indicating loss of paranodal junctions and impaired fast axonal transport, respectively. Measurements showing decreased PN-ir with increased APP-ir quantitatively defined a pattern of early axonal damage in autoimmune optic neuritis.
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Affiliation(s)
- Martha E Stokely
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107, USA
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Rao VR, Krishnamoorthy RR, Yorio T. Endothelin-1, endothelin A and B receptor expression and their pharmacological properties in GFAP negative human lamina cribrosa cells. Exp Eye Res 2007; 84:1115-24. [PMID: 17433294 DOI: 10.1016/j.exer.2007.02.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Revised: 02/02/2007] [Accepted: 02/12/2007] [Indexed: 11/18/2022]
Abstract
Primary open angle glaucoma (POAG) is a progressive optic neuropathy, characterized, in part by extensive extra cellular matrix remodeling and collapse of the lamina cribrosa (LC). Endothelin-1 (ET-1), a potent vasoactive peptide and its receptors, endothelin receptor A (ET(A)) and endothelin receptor B (ET(B)), have been implicated in glaucomatous optic neuropathy. In this study we examined the expression of ET-1 and its receptors in GFAP negative LC cells. RT-PCR analysis revealed that LC cells express both ET(A), ET(B) receptors and prepro- ET-1, the primary gene transcript of ET-1. A dose-dependent increase in intra-cellular calcium concentrations was observed in the presence of 1, 10 and 100nM ET-1. Increased intracellular calcium concentrations were blocked by the ET(A) selective antagonist BQ610 but not by the ET(B) specific antagonist BQ788. Desensitization to ET(A)-mediated increase in intracellular calcium was observed in LC cells following pre-treatment with ET-1 for 24h. Western blot analysis of LC cells treated with ET-1 for 24h revealed a decreased expression of ET(A) receptor protein at 1, 10 and 100nM concentrations, while a dose dependent increase in the ET(B) receptor was observed with a significant increase at 100nM. Quantitative PCR showed a dose-dependent decrease in ET(A) receptor mRNA levels and an increase in the mRNA levels of ET(B) receptors. A Griess colorimetric assay was used to measure the NO released from LC cells and ET-1 induced a dose-dependent increase in NO release which was significant at 100nM concentration. ET-1 induced NO release was significantly blocked by BQ788, an ET(B) selective antagonist, and as well as BQ610, an ET(A) selective antagonist. These results suggested that human lamina cribrosa cells expressed functional ET(A) and ET(B) receptors and their expression and function was altered in response to prolong exposure to ET-1. This may have an implication in the normal physiology of LC cells and in POAG subjects where elevated levels of ET-1 could impact LC function.
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Affiliation(s)
- Vidhya R Rao
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
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Syed H, Safa R, Chidlow G, Osborne NN. Sulfisoxazole, an endothelin receptor antagonist, protects retinal neurones from insults of ischemia/reperfusion or lipopolysaccharide. Neurochem Int 2006; 48:708-17. [PMID: 16464516 DOI: 10.1016/j.neuint.2005.12.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Revised: 12/07/2005] [Accepted: 12/19/2005] [Indexed: 12/29/2022]
Abstract
Endothelins exert pathological effects in the eye and much interest centres on their role in causing retinal neuronal death in ischemic diseases like glaucoma. In the present study the influence of the non-selective endothelin antagonist, sulfisoxazole on raised intraocular pressure-induced ischemia to the rat retina was investigated. Moreover, in vitro studies on primary rat retinal cultures were undertaken to see whether sulfisoxazole is able to blunt the toxic effect of lipopolysaccharide (LPS) to retinal neurones. In order to determine whether sulfisoxazole provides protection to the retina the a- and b-wave amplitudes of the electroretinogram (ERG), the localisation of retinal choline acetyltransferase (ChAT), nitric oxide synthase (nNOS) and Thy-1 and the retinal mRNA levels of Thy-1 and FGF-2 were deduced in retinas subjected to ischemia in the absence or presence of sulfisoxazole. The results showed that the ischemia-induced changes to the a- and b-wave amplitudes of the ERG and changes associated with the localisation of ChAT, nNOS and Thy-1 to be significantly blunted by sulfisoxazole. However, while the ischemia-induced changes to Thy-1 and FGF-2 mRNAs were reduced by sulfisoxazole, the reduction was non-significant. The in vitro studies provided support for the protective effect of sulfisoxazole. Here, it was clearly shown that sulfisoxazole attenuated the elevation of nitric oxide (deduced by measuring nitrite) and the reduction in numbers of GABA-containing neurones caused by LPS. The present study provides evidence for the first time that endothelin antagonist can protect the retina from ischemic-like insults as occurs in glaucoma.
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Affiliation(s)
- Husnain Syed
- Nuffield Laboratory of Ophthalmology, Oxford University, Walton Street, Oxford OX2 6AW, UK
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