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Sheng X, Zhang C, Zhao J, Xu J, Zhang P, Ding Q, Zhang J. Microvascular destabilization and intricated network of the cytokines in diabetic retinopathy: from the perspective of cellular and molecular components. Cell Biosci 2024; 14:85. [PMID: 38937783 PMCID: PMC11212265 DOI: 10.1186/s13578-024-01269-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Accepted: 06/19/2024] [Indexed: 06/29/2024] Open
Abstract
Microvascular destabilization is the primary cause of the inner blood-retinal barrier (iBRB) breakdown and increased vascular leakage in diabetic retinopathy (DR). Microvascular destabilization results from the combinational effects of increased levels of growth factors and cytokines, involvement of inflammation, and the changed cell-to-cell interactions, especially the loss of endothelial cells and pericytes, due to hyperglycemia and hypoxia. As the manifestation of microvascular destabilization, the fluid transports via paracellular and transcellular routes increase due to the disruption of endothelial intercellular junctional complexes and/or the altered caveolar transcellular transport across the retinal vascular endothelium. With diabetes progression, the functional and the structural changes of the iBRB components, including the cellular and noncellular components, further facilitate and aggravate microvascular destabilization, resulting in macular edema, the neuroretinal damage and the dysfunction of retinal inner neurovascular unit (iNVU). Although there have been considerable recent advances towards a better understanding of the complex cellular and molecular network underlying the microvascular destabilization, some still remain to be fully elucidated. Recent data indicate that targeting the intricate signaling pathways may allow to against the microvascular destabilization. Therefore, efforts have been made to better clarify the cellular and molecular mechanisms that are involved in the microvascular destabilization in DR. In this review, we discuss: (1) the brief introduction of DR and microvascular destabilization; (2) the cellular and molecular components of iBRB and iNVU, and the breakdown of iBRB; (3) the matrix and cell-to-cell contacts to maintain microvascular stabilization, including the endothelial glycocalyx, basement membrane, and various cell-cell interactions; (4) the molecular mechanisms mediated cell-cell contacts and vascular cell death; (5) the altered cytokines and signaling pathways as well as the intricate network of the cytokines involved in microvascular destabilization. This comprehensive review aimed to provide the insights for microvascular destabilization by targeting the key molecules or specific iBRB cells, thus restoring the function and structure of iBRB and iNVU, to treat DR.
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Affiliation(s)
- Xia Sheng
- People's Hospital of Huangdao District, Qingdao, Shandong Province, China
| | - Chunmei Zhang
- People's Hospital of Huangdao District, Qingdao, Shandong Province, China
| | - Jiwei Zhao
- People's Hospital of Huangdao District, Qingdao, Shandong Province, China
| | - Jianping Xu
- People's Hospital of Huangdao District, Qingdao, Shandong Province, China.
| | - Peng Zhang
- People's Hospital of Huangdao District, Qingdao, Shandong Province, China.
| | - Quanju Ding
- People's Hospital of Huangdao District, Qingdao, Shandong Province, China.
| | - Jingfa Zhang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, National Clinical Research Center for Eye Diseases, Shanghai, China.
- The International Eye Research Institute of The Chinese University of Hong Kong (Shenzhen), Shenzhen, China.
- C-MER (Shenzhen) Dennis Lam Eye Hospital, Shenzhen, China.
- C-MER International Eye Care Group, C-MER Dennis Lam & Partners Eye Center, Hong Kong, China.
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2
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Carpi-Santos R, de Melo Reis RA, Gomes FCA, Calaza KC. Contribution of Müller Cells in the Diabetic Retinopathy Development: Focus on Oxidative Stress and Inflammation. Antioxidants (Basel) 2022; 11:antiox11040617. [PMID: 35453302 PMCID: PMC9027671 DOI: 10.3390/antiox11040617] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/01/2022] [Accepted: 03/15/2022] [Indexed: 01/27/2023] Open
Abstract
Diabetic retinopathy is a neurovascular complication of diabetes and the main cause of vision loss in adults. Glial cells have a key role in maintenance of central nervous system homeostasis. In the retina, the predominant element is the Müller cell, a specialized cell with radial morphology that spans all retinal layers and influences the function of the entire retinal circuitry. Müller cells provide metabolic support, regulation of extracellular composition, synaptic activity control, structural organization of the blood–retina barrier, antioxidant activity, and trophic support, among other roles. Therefore, impairments of Müller actions lead to retinal malfunctions. Accordingly, increasing evidence indicates that Müller cells are affected in diabetic retinopathy and may contribute to the severity of the disease. Here, we will survey recently described alterations in Müller cell functions and cellular events that contribute to diabetic retinopathy, especially related to oxidative stress and inflammation. This review sheds light on Müller cells as potential therapeutic targets of this disease.
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Affiliation(s)
- Raul Carpi-Santos
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; (R.C.-S.); (F.C.A.G.)
| | - Ricardo A. de Melo Reis
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil;
| | - Flávia Carvalho Alcantara Gomes
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; (R.C.-S.); (F.C.A.G.)
| | - Karin C. Calaza
- Instituto de Biologia, Departamento de Neurobiologia, Universidade Federal Fluminense, Niteroi 24210-201, RJ, Brazil
- Correspondence:
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Kumar S, Quach J, Cook N, Gum G, Naageshwaran V. Characterization and validation of a chronic retinal neovascularization rabbit model by evaluating the efficacy of anti-angiogenic and anti-inflammatory drugs. Int J Ophthalmol 2022; 15:15-22. [PMID: 35047351 DOI: 10.18240/ijo.2022.01.03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 08/11/2021] [Indexed: 11/23/2022] Open
Abstract
AIM To establish a rabbit model with chronic condition of retinal neovascularization (RNV) induced by intravitreal (IVT) injection of DL-2-aminoadipic acid (DL-AAA), a retinal glial (Müller) cell toxin, extensive characterization of DL-AAA induced angiographic features and the suitability of the model to evaluate anti-angiogenic and anti-inflammatory therapies for ocular vascular diseases. METHODS DL-AAA (80 mmol/L) was administered IVT into both eyes of Dutch Belted rabbit. Post DL-AAA delivery, clinical ophthalmic examinations were performed weekly following modified McDonald-Shadduck Scoring System. Color fundus photography, fluorescein angiography (FA), and optical coherence tomography (OCT) procedures were performed every 2 or 4wk until stable retinal vascular leakage was observed. Once stable retinal leakage (12wk post DL-AAA administration) was established, anti-vascular endothelial growth factor (VEGF) (bevacizumab, ranibizumab and aflibercept) and anti-inflammatory (triamcinolone, TAA) drugs were tested for their efficacy after IVT administration. Fluorescein angiograms were scored before and after treatment following a novel grading system, developed for the DL-AAA rabbit model. RESULTS Post DL-AAA administration, eyes were presented with moderate to severe retinal/choroidal inflammation which was accompanied by intense vitreous flare and presence of inflammatory cells in the vitreous humor. Retinal hemorrhage was restricted to the tips of neo-retinal vessels. FA revealed maximum retinal vascular leakage at 2wk after DL-AAA injection and then persisted as evidenced by stable mean FA scores in weeks 8 and 12. Retinal vascular angiographic and tomographic features were stable and consistent up to 36mo among two different staggers induced for RNV at two different occasions. Day 7, mean FA scores showed that 1 µg/eye of bevacizumab, ranibizumab, aflibercept and 2 µg/eye of TAA suppress 65%, 90%, 100% and 50% retinal vascular leakage, respectively. Day 30, bevacizumab and TAA continued to show 66% and 44% suppression while ranibizumab effect was becoming less effective (68%). In contrast, aflibercept was still able to fully (100%) suppress vascular leakage on day 30. On day 60, bevacizumab, ranibizumab and TAA showed suppression of 7%, 12%, and 9% retinal vascular leakage, respectively, however, aflibercept continued to be more effective showing 50% suppression of vascular leakage. CONCLUSION The DL-AAA rabbit model mimics RNV angiographic features like RNV and chronic retinal leakage. Based on these features the DL-AAA rabbit model provides an invaluable tool that could be used to test the therapeutic efficacy and duration of action of novel anti-angiogenic formulations, alone or in combination with anti-inflammatory compounds.
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Affiliation(s)
- Sandeep Kumar
- Department of Ophthalmology, Absorption Systems: a Pharmaron company, 7901 Vickers St, San Diego, CA 92111, USA
| | - John Quach
- Department of Ophthalmology, Absorption Systems: a Pharmaron company, 7901 Vickers St, San Diego, CA 92111, USA
| | - Nicholas Cook
- Department of Ophthalmology, Absorption Systems: a Pharmaron company, 7901 Vickers St, San Diego, CA 92111, USA
| | - Glenwood Gum
- Department of Ophthalmology, Absorption Systems: a Pharmaron company, 7901 Vickers St, San Diego, CA 92111, USA
| | - Vatsala Naageshwaran
- Department of Ophthalmology, Absorption Systems: a Pharmaron company, 7901 Vickers St, San Diego, CA 92111, USA
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Özgümüs T, Sulaieva O, Jain R, Artner I, Lyssenko V. Starvation to Glucose Reprograms Development of Neurovascular Unit in Embryonic Retinal Cells. Front Cell Dev Biol 2021; 9:726852. [PMID: 34869314 PMCID: PMC8636675 DOI: 10.3389/fcell.2021.726852] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 10/25/2021] [Indexed: 12/13/2022] Open
Abstract
Perinatal exposure to starvation is a risk factor for development of severe retinopathy in adult patients with diabetes. However, the underlying mechanisms are not completely understood. In the present study, we shed light on molecular consequences of exposure to short-time glucose starvation on the transcriptome profile of mouse embryonic retinal cells. We found a profound downregulation of genes regulating development of retinal neurons, which was accompanied by reduced expression of genes encoding for glycolytic enzymes and glutamatergic signaling. At the same time, glial and vascular markers were upregulated, mimicking the diabetes-associated increase of angiogenesis—a hallmark of pathogenic features in diabetic retinopathy. Energy deprivation as a consequence of starvation to glucose seems to be compensated by upregulation of genes involved in fatty acid elongation. Results from the present study demonstrate that short-term glucose deprivation during early fetal life differentially alters expression of metabolism- and function-related genes and could have detrimental and lasting effects on gene expression in the retinal neurons, glial cells, and vascular elements and thus potentially disrupting gene regulatory networks essential for the formation of the retinal neurovascular unit. Abnormal developmental programming during retinogenesis may serve as a trigger of reactive gliosis, accelerated neurodegeneration, and increased vascularization, which may promote development of severe retinopathy in patients with diabetes later in life.
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Affiliation(s)
- Türküler Özgümüs
- Department of Clinical Science, Center for Diabetes Research, University of Bergen, Bergen, Norway
| | | | - Ruchi Jain
- Department of Clinical Sciences, Lund University Diabetes Centre, Skåne University Hospital, Malmö, Sweden
| | - Isabella Artner
- Department of Clinical Sciences, Lund University Diabetes Centre, Skåne University Hospital, Malmö, Sweden
| | - Valeriya Lyssenko
- Department of Clinical Science, Center for Diabetes Research, University of Bergen, Bergen, Norway.,Department of Clinical Sciences, Lund University Diabetes Centre, Skåne University Hospital, Malmö, Sweden
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Dietary Supplement Enriched in Antioxidants and Omega-3 Promotes Glutamine Synthesis in Müller Cells: A Key Process against Oxidative Stress in Retina. Nutrients 2021; 13:nu13093216. [PMID: 34579093 PMCID: PMC8468588 DOI: 10.3390/nu13093216] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/26/2021] [Accepted: 09/11/2021] [Indexed: 12/16/2022] Open
Abstract
To prevent ocular pathologies, new generation of dietary supplements have been commercially available. They consist of nutritional supplement mixing components known to provide antioxidative properties, such as unsaturated fatty acid, resveratrol or flavonoids. However, to date, only one preclinical study has evaluated the impact of a mixture mainly composed of those components (Nutrof Total®) on the retina and demonstrated that in vivo supplementation prevents the retina from structural and functional injuries induced by light. Considering the crucial role played by the glial Müller cells in the retina, particularly to regulate the glutamate cycle to prevent damage in oxidative stress conditions, we questioned the impact of this ocular supplement on the glutamate metabolic cycle. To this end, various molecular aspects associated with the glutamate/glutamine metabolism cycle in Müller cells were investigated on primary Müller cells cultures incubated, or not, with the commercially mix supplement before being subjected, or not, to oxidative conditions. Our results demonstrated that in vitro supplementation provides guidance of the glutamate/glutamine cycle in favor of glutamine synthesis. These results suggest that glutamine synthesis is a crucial cellular process of retinal protection against oxidative damages and could be a key step in the previous in vivo beneficial results provided by the dietary supplementation.
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Yu Y, Qin Y, Fu J, Li Y, Zhang W, Zhu T, Jiang L, Wang X, Paulus YM. Long-term multimodal imaging characterization of persistent retinal neovascularization using DL-alpha-aminoadipic acid in pigmented and white rabbits. Exp Eye Res 2021; 207:108577. [PMID: 33864785 DOI: 10.1016/j.exer.2021.108577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 03/06/2021] [Accepted: 04/08/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE Intravitreal (IVT) injection of DL-alpha-aminoadipic acid (AAA) is a new animal model for retinal neovascularization (RNV) reported in rabbits. This study performs longitudinal multimodal imaging for up to 1 year to evaluate DL-AAA RNV in both New Zealand white (NZW) rabbits and Dutch-Belted pigmented (DBP) rabbits. METHOD Detailed characterization and quantification of this model were performed in these two strains in 32 eyes by optical coherence tomography (OCT), fundus photography, and fluorescein angiography (FA) for up to 16 weeks following DL-AAA administration in 32 eyes and up to 52 weeks in 5 eyes. H & E histology was also performed in these two strains 8 weeks after injection of DL-AAA. RESULT RNV was successfully generated using 50 μL 80 mM DL-AAA solution for DBP rabbits and 80 μL 80 mM DL-AAA for NZW rabbits. The incidence of persistent vascular leakage is 100% (15/15) for DBP rabbits and 70.6% (12/17) for NZW rabbits at 16 weeks. Complications with NZW rabbits ultimately decreased the efficiency in NZW rabbits to 58.8% (10/17) of NZW rabbits getting persistent (to 16 weeks) vascular leakage without ocular complications as compared with 100% (15/15) in DBP rabbits. Five eyes (2 DBP and 3 NZW) were selected from those demonstrating RNV at 16 weeks and were monitored for up to 52 weeks. All 5 demonstrated persistent RNV to 52 weeks. Quantification of the mean leakage area (MLA) in DBP rabbits is more accurate than in NZW rabbits since the reduced contrast between the leakage and background in NZW rabbits makes it more challenging to quantify. CONCLUSION DL-AAA can induce persistent and quantifiable RNV in both DBP and NZW rabbits. DBP rabbits have a higher success rate, lower required volume of DL-AAA, and more accurate method for quantification that could be more desirable.
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Affiliation(s)
- Yixin Yu
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA; Eye Center of Xiangya Hospital, Central South University, Changsha, Hunan Province, China; Hunan Key Laboratory of Ophthalmology, Changsha, Hunan Province, China
| | - Yu Qin
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Julia Fu
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Yanxiu Li
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA; Eye Center of Xiangya Hospital, Central South University, Changsha, Hunan Province, China; Hunan Key Laboratory of Ophthalmology, Changsha, Hunan Province, China
| | - Wei Zhang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Tianye Zhu
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Longtan Jiang
- Department of Cardiac Surgery, The University of Michigan, Ann Arbor, MI, 48109, USA; Department of Cardiovascular Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China
| | - Xueding Wang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Yannis M Paulus
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
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Buck TM, Vos RM, Alves CH, Wijnholds J. AAV- CRB2 protects against vision loss in an inducible CRB1 retinitis pigmentosa mouse model. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2020; 20:423-441. [PMID: 33575434 PMCID: PMC7848734 DOI: 10.1016/j.omtm.2020.12.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 12/21/2020] [Indexed: 01/31/2023]
Abstract
Loss of Crumbs homolog 1 (CRB1) or CRB2 proteins in Müller cells or photoreceptors in the mouse retina results in a CRB dose-dependent retinal phenotype. In this study, we present a novel Müller cell-specific Crb1KOCrb2LowMGC retinitis pigmentosa mouse model (complete loss of CRB1 and reduced levels of CRB2 specifically in Müller cells). The Crb double mutant mice showed deficits in electroretinography, optokinetic head tracking, and retinal morphology. Exposure of retinas to low levels of dl-α-aminoadipate acid induced gliosis and retinal disorganization in Crb1KOCrb2LowMGC retinas but not in wild-type or Crb1-deficient retinas. Crb1KOCrb2LowMGC mice showed a substantial decrease in inner/outer photoreceptor segment length and optokinetic head-tracking response. Intravitreal application of rAAV vectors expressing human CRB2 (hCRB2) in Müller cells of Crb1KOCrb2LowMGC mice subsequently exposed to low levels of dl-α-aminoadipate acid prevented loss of vision, whereas recombinant adeno-associated viral (rAAV) vectors expressing human CRB1 (hCRB1) did not. Both rAAV vectors partially protected the morphology of the retina. The results suggest that hCRB expression in Müller cells is vital for control of retinal cell adhesion at the outer limiting membrane, and that the rAAV-cytomegalovirus (CMV)-hCRB2 vector is more potent than rAAV-minimal CMV (CMVmin)-hCRB1 in protection against loss of vision.
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Affiliation(s)
- Thilo M Buck
- Department of Ophthalmology, Leiden University Medical Center (LUMC), 2333 ZC Leiden, the Netherlands
| | - Rogier M Vos
- Netherlands Institute of Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), 1105 BA Amsterdam, the Netherlands
| | - C Henrique Alves
- Department of Ophthalmology, Leiden University Medical Center (LUMC), 2333 ZC Leiden, the Netherlands
| | - Jan Wijnholds
- Department of Ophthalmology, Leiden University Medical Center (LUMC), 2333 ZC Leiden, the Netherlands.,Netherlands Institute of Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), 1105 BA Amsterdam, the Netherlands
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8
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Patel C, Goody R, Hu W, Kurian A, James D, Torres R, Christie LA, Hohman T, Lawrence M. Primate model of chronic retinal neovascularization and vascular leakage. Exp Eye Res 2020; 195:108031. [PMID: 32275921 DOI: 10.1016/j.exer.2020.108031] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 11/26/2022]
Abstract
The purpose of this study was to characterize and develop a primate model of chronic retinal neovascularization and vascular leakage that can be employed to assess efficacy of experimental therapeutics targeting retinal ischemic and neovascular diseases. African green monkeys received bilateral intravitreal (IVT) injection of DL-alpha-aminoadipic acid (DLAAA; 5 mg) following ophthalmic examination, color fundus photography, fluorescein angiography (FA) and optical coherence tomography (OCT). Imaging was repeated to evaluate progression and subsequent stabilization of retinal vascular pathology elicited by DLAAA. Aflibercept (Eylea) was administered IVT (1.4 mg) to assess effects on vascular leakage. Ocular tissue was collected for histopathology and glial fibrillary acidic protein (GFAP), von Willebrand Factor (vWF), CD105/endoglin, VEGF and CD68 immunohistochemistry to study retinal degeneration and vascular remodeling. IVT DLAAA administration resulted in telangiectatic vessel formation as early as two-weeks post-injection, followed by retinal vascular leakage and inner retinal edema. Neovascular lesion progression was evident up to 8-10 weeks post-injection before stabilizing into a vascular leakage state that persisted beyond 90 weeks. Histopathology and immunostaining revealed retinal degeneration and neovascularization, increased expression of vWF, CD105/endoglin, VEGF and CD68 immunoreactivities in addition to Müller cell loss. Aflibercept significantly attenuated vascular leakage for 2-4 weeks before progressive return of leakage from weeks 4-8. Lesions remained responsive to anti-VEGF administration at 90 weeks after DLAAA injection. Findings support application of the primate DLAAA-induced retinal vascular leakage model for efficacy evaluations of candidate therapeutics and sustained release strategies targeting exudative AMD, diabetic retinopathy, macular telangiectasia and other retinal ischemic and neovascular diseases. Findings confirm relevance of the DLAAA primate phenotype to understanding shared retinal vascular disease mechanisms and macular susceptibility to vascular and metabolic insults.
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Affiliation(s)
- Chintan Patel
- Virscio, Inc., 4 Science Park, New Haven, CT 06511, USA.
| | - Robin Goody
- Virscio, Inc., 4 Science Park, New Haven, CT 06511, USA
| | - Wenzheng Hu
- Virscio, Inc., 4 Science Park, New Haven, CT 06511, USA
| | - Anish Kurian
- Virscio, Inc., 4 Science Park, New Haven, CT 06511, USA
| | | | - Richard Torres
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT 06510, USA
| | - Lori-Ann Christie
- Department of Biological Sciences, Allergan plc, 2525 Dupont Drive, Irvine, CA 92612, USA
| | - Thomas Hohman
- Envision Consulting, LLC, 2009 Glenwood Dr, Ocean City, NJ 08226, USA
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Ma M, Zhao S, Zhang J, Sun T, Fan Y, Zheng Z. High Glucose-Induced TRPC6 Channel Activation Decreases Glutamate Uptake in Rat Retinal Müller Cells. Front Pharmacol 2020; 10:1668. [PMID: 32116675 PMCID: PMC7033573 DOI: 10.3389/fphar.2019.01668] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 12/20/2019] [Indexed: 12/15/2022] Open
Abstract
High glucose (HG) increases the production of reactive oxygen species (ROS), leading to decreased glutamate uptake in Müller cells. The transient receptor potential cation channel 6 (TRPC6) channel, an oxidative stress-sensitive Ca2+-permeable cationic channel, is readily detected in Müller cells and highly expressed under HG conditions. Yet, the effect of high glucose-induced TRPC6 channel activation in Müller cells is poorly understood. We hypothesized that TRPC6 channel activation mediates high glucose-induced decreases in Müller cell glutamate uptake. We found RNA interference (RNAi) of the TRPC6 channel abolished HG-induced decreases in glutamate uptake and cell death. HG also decreased the expression of the glutamate-aspartate transporter (GLAST), which is the most important transporter involved in glutamate uptake. The mRNA level of ciliary neurotrophic factor (CNTF) in rMC-1 cells and the release of CNTF in the culture media was decreased, but the mRNA levels of IL-6 and vascular endothelial growth factor (VEGF) were increased under HG conditions. After RNAi silencing in rMC-1 cells, the mRNA levels of CNTF increased, but IL-6 and VEGF levels decreased. Furthermore, TRPC6 knockdown (KD) decreased expression of glial fibrillary acidic protein (GFAP) and increased expression of Kir4.1, pointing to inhibition of HG-induced gliosis in rMC-1 cells. ROS and intracellular Ca2+ levels decreased after TRPC6 knockdown. Exposure to Hyp9 (10 μM), a highly selective TRPC6 channel agonist, can aggravate HG-induced pathological changes. Collectively, our results suggest TRPC6 channel activation is involved in HG-induced decreases in glutamate uptake in rMC-1 cells. These findings provide novel insights into the role of TRPC6 in HG-induced retinal neurovasculopathy and suggest TRPC6 is a promising target for drug development for diabetic retinopathy (DR).
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Affiliation(s)
- Mingming Ma
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Shuzhi Zhao
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Jian Zhang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Tao Sun
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Ying Fan
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Zhi Zheng
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
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10
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Xie J, Li Y, Dai J, He Y, Sun D, Dai C, Xu H, Yin ZQ. Olfactory Ensheathing Cells Grafted Into the Retina of RCS Rats Suppress Inflammation by Down-Regulating the JAK/STAT Pathway. Front Cell Neurosci 2019; 13:341. [PMID: 31402855 PMCID: PMC6670006 DOI: 10.3389/fncel.2019.00341] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 07/11/2019] [Indexed: 01/23/2023] Open
Abstract
The inflammatory microenvironment in the retina plays a vital role in the pathogenesis and progression of retinitis pigmentosa (RP). Microglial inflammatory cytokines production leads to gliosis and apoptosis of retinal neurons, and ultimately, visual loss. Cell-based therapies using grafted olfactory ensheathing cells (OECs) have demonstrated modulation of degenerative microenvironments in the central nervous system (CNS), in a number of animal models. However, mechanisms by which grafted OECs can reduce degeneration in the retina are not well understood. In the present study, we set up an in vitro OEC/BV2 microglia co-culture system, and an in vivo royal college of surgeons (RCS) rat model, used cell transplantation, immunohistochemistry, RT-PCR, western blot to explore the mechanisms by which OECs affect expression of pro- or anti-inflammatory cytokines and polarization of M(IL-6) and M(Arg1) type microglial activation in the retina. We found that compared with the LPS (Lipopolysaccharide) and olfactory nerve fibroblast (ONF), the OEC and BV2 co-culture group modulate microglial cytokines releasing toward the anti-inflammation, and away from the pro-inflammation, which was followed by higher IL-4 and IL-10 and lower TNF-a and IL-6 in their expression levels. In vivo, the transplantation group significantly reduced activated resident microglia/infiltrated macrophage, and expression of pro-inflammatory cytokines in RCS rats retina, increased anti-inflammatory cytokines in transplantation area. Additionally, we found that OECs expressed SOCS3 and down-regulated the JAK2/STAT3 (Janus Kinase 2/Signal Transducer and Activator of Transcription 3) pathway. Thirdly, OEC transplantation reduced Caspase-3 expression, protected inner retinal neurons and photoreceptors and therefore, delayed the visual function degeneration. In conclusion, our data suggest that OECs delay retinal degeneration in RP, at least in part through immunomodulation of microglia via the JAK/STAT pathway.
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Affiliation(s)
- Jing Xie
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China.,Key Laboratory of Visual Damage, Regeneration and Restoration of Chongqing, Chongqing, China
| | - Yijian Li
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China.,Key Laboratory of Visual Damage, Regeneration and Restoration of Chongqing, Chongqing, China
| | - Jiaman Dai
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China.,Key Laboratory of Visual Damage, Regeneration and Restoration of Chongqing, Chongqing, China
| | - Yan He
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China.,Key Laboratory of Visual Damage, Regeneration and Restoration of Chongqing, Chongqing, China
| | - Dayu Sun
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China.,Key Laboratory of Visual Damage, Regeneration and Restoration of Chongqing, Chongqing, China
| | - Chao Dai
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China.,Key Laboratory of Visual Damage, Regeneration and Restoration of Chongqing, Chongqing, China
| | - Haiwei Xu
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China.,Key Laboratory of Visual Damage, Regeneration and Restoration of Chongqing, Chongqing, China
| | - Zheng Qin Yin
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China.,Key Laboratory of Visual Damage, Regeneration and Restoration of Chongqing, Chongqing, China
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11
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Someya E, Akagawa M, Mori A, Morita A, Yui N, Asano D, Sakamoto K, Nakahara T. Role of Neuron⁻Glia Signaling in Regulation of Retinal Vascular Tone in Rats. Int J Mol Sci 2019; 20:ijms20081952. [PMID: 31010057 PMCID: PMC6514555 DOI: 10.3390/ijms20081952] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 04/17/2019] [Accepted: 04/17/2019] [Indexed: 12/19/2022] Open
Abstract
The interactions between neuronal, glial, and vascular cells play a key role in regulating blood flow in the retina. In the present study, we examined the role of the interactions between neuronal and glial cells in regulating the retinal vascular tone in rats upon stimulation of retinal neuronal cells by intravitreal injection of N-methyl-d-aspartic acid (NMDA). The retinal vascular response was assessed by measuring the diameter of the retinal arterioles in the in vivo fundus images. Intravitreal injection of NMDA produced retinal vasodilation that was significantly diminished following the pharmacological inhibition of nitric oxide (NO) synthase (nNOS), loss of inner retinal neurons, or intravitreal injection of glial toxins. Immunohistochemistry revealed the expression of nNOS in ganglion and calretinin-positive amacrine cells. Moreover, glial toxins significantly prevented the retinal vasodilator response induced by intravitreal injection of NOR3, an NO donor. Mechanistic analysis revealed that NO enhanced the production of vasodilatory prostanoids and epoxyeicosatrienoic acids in glial cells in a ryanodine receptor type 1-dependent manner, subsequently inducing the retinal vasodilator response. These results suggest that the NO released from stimulated neuronal cells acts as a key messenger in neuron–glia signaling, thereby causing neuronal activity-dependent and glial cell-mediated vasodilation in the retina.
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Affiliation(s)
- Eriko Someya
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
| | - Mari Akagawa
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
| | - Asami Mori
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
| | - Akane Morita
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
| | - Natsuko Yui
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
| | - Daiki Asano
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
| | - Kenji Sakamoto
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
| | - Tsutomu Nakahara
- Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
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12
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Mages K, Grassmann F, Jägle H, Rupprecht R, Weber BHF, Hauck SM, Grosche A. The agonistic TSPO ligand XBD173 attenuates the glial response thereby protecting inner retinal neurons in a murine model of retinal ischemia. J Neuroinflammation 2019; 16:43. [PMID: 30777091 PMCID: PMC6378755 DOI: 10.1186/s12974-019-1424-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 01/31/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Ligand-driven modulation of the mitochondrial translocator protein 18 kDa (TSPO) was recently described to dampen the neuroinflammatory response of microglia in a retinal light damage model resulting in protective effects on photoreceptors. We characterized the effects of the TSPO ligand XBD173 in the postischemic retina focusing on changes in the response pattern of the major glial cell types of the retina-microglia and Müller cells. METHODS Retinal ischemia was induced by increasing the intraocular pressure for 60 min followed by reperfusion of the tissue in mice. On retinal cell types enriched via immunomagnetic separation expression analysis of TSPO, its ligand diazepam-binding inhibitor (DBI) and markers of glial activation were performed at transcript and protein level using RNA sequencing, qRT-PCR, lipid chromatography-mass spectrometry, and immunofluorescent labeling. Data on cell morphology and numbers were assessed in retinal slice and flatmount preparations. The retinal functional integrity was determined by electroretinogram recordings. RESULTS We demonstrate that TSPO is expressed by Müller cells, microglia, vascular cells, retinal pigment epithelium (RPE) of the healthy and postischemic retina, but only at low levels in retinal neurons. While an alleviated neurodegeneration upon XBD173 treatment was found in postischemic retinae as compared to vehicle controls, this neuroprotective effect of XBD173 is mediated putatively by its action on retinal glia. After transient ischemia, TSPO as a marker of activation was upregulated to similar levels in microglia as compared to their counterparts in healthy retinae irrespective of the treatment regimen. However, less microglia were found in XBD173-treated postischemic retinae at 3 days post-surgery (dps) which displayed a more ramified morphology than in retinae of vehicle-treated mice indicating a dampened microglia activation. Müller cells, the major retinal macroglia, show upregulation of the typical gliosis marker GFAP. Importantly, glutamine synthetase was more stably expressed in Müller glia of XBD173-treated postischemic retinae and homeostatic functions such as cellular volume regulation typically diminished in gliotic Müller cells remained functional. CONCLUSIONS In sum, our data imply that beneficial effects of XBD173 treatment on the postischemic survival of inner retinal neurons were primarily mediated by stabilizing neurosupportive functions of glial cells.
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Affiliation(s)
- Kristin Mages
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
| | - Felix Grassmann
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany.,Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Nobels väg 12A, Stockholm, Sweden
| | - Herbert Jägle
- Department of Ophthalmology, University of Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
| | - Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053, Regensburg, Germany
| | - Bernhard H F Weber
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
| | - Stefanie M Hauck
- Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Heidemannstraße 1, 80939, Munich, Germany
| | - Antje Grosche
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany. .,Department of Physiological Genomics, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152, Planegg-Martinsried, Germany.
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13
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Kokona D, Ebneter A, Escher P, Zinkernagel MS. Colony-stimulating factor 1 receptor inhibition prevents disruption of the blood-retina barrier during chronic inflammation. J Neuroinflammation 2018; 15:340. [PMID: 30541565 PMCID: PMC6292111 DOI: 10.1186/s12974-018-1373-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 11/19/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Microglia-associated inflammation is closely related to the pathogenesis of various retinal diseases such as uveitis and diabetic retinopathy, which are associated with increased vascular permeability. In this study, we investigated the effect of systemic lipopolysaccharide (LPS) exposure to activation and proliferation of retinal microglia /macrophages. METHODS Balb/c and Cx3cr1gfp/+ mice were challenged with LPS (1 mg/kg) daily for four consecutive days. For microglia depletion, mice were treated with colony-stimulating factor 1 receptor (CSF-1R) inhibitor PLX5622 1 week before the first LPS challenge and until the end of the experiment. In vivo imaging of the retina was performed on days 4 and 7 after the first LPS challenge, using optical coherence tomography and fluorescein angiography. Flow cytometry analysis, retinal whole mount, and retinal sections were used to investigate microglia and macrophage infiltration and proliferation after LPS challenge. Cytokines were analyzed in the blood as well as in the retina. Data analysis was performed using unpaired t tests, repeated measures one-way ANOVA, or ordinary one-way ANOVA followed by Tukey's post hoc analysis. Kruskal-Wallis test followed by Dunn's multiple comparison tests was used for the analysis of non-normally distributed data. RESULTS Repeated LPS challenge led to activation and proliferation of retinal microglia, infiltration of monocyte-derived macrophages into the retina, and breakdown of the blood-retina barrier (BRB) accompanied by accumulation of sub-retinal fluid. Using in vivo imaging, we show that the breakdown of the BRB is highly reproducible but transitory. Acute but not chronic systemic exposure to LPS triggered a robust release of inflammatory mediators in the retina with minimal effects in the blood plasma. Inhibition of the CSF-1R by PLX5622 resulted in depletion of retinal microglia, suppression of cytokine production in the retina, and prevention of BRB breakdown. CONCLUSIONS These findings suggest that microglia/macrophages play an important role in the pathology of retinal disorders characterized by breakdown of the BRB, and suppression of their activation may be a potential therapeutic target for such retinopathies.
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Affiliation(s)
- Despina Kokona
- Department of Ophthalmology, Inselspital, Bern University Hospital, and University of Bern, CH-3010, Bern, Switzerland.,Department of Clinical Research, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - Andreas Ebneter
- Department of Ophthalmology, Inselspital, Bern University Hospital, and University of Bern, CH-3010, Bern, Switzerland.,Department of Clinical Research, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - Pascal Escher
- Department of Ophthalmology, Inselspital, Bern University Hospital, and University of Bern, CH-3010, Bern, Switzerland.,Department of Clinical Research, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - Martin S Zinkernagel
- Department of Ophthalmology, Inselspital, Bern University Hospital, and University of Bern, CH-3010, Bern, Switzerland. .,Department of Clinical Research, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland.
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14
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Dai J, Fu Y, Zeng Y, Li S, Qin Yin Z. Improved retinal function in RCS rats after suppressing the over-activation of mGluR5. Sci Rep 2017; 7:3546. [PMID: 28615682 PMCID: PMC5471183 DOI: 10.1038/s41598-017-03702-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 05/03/2017] [Indexed: 01/09/2023] Open
Abstract
Müller cells maintain retinal synaptic homeostasis by taking up glutamate from the synaptic cleft and transporting glutamine back to the neurons. To study the interaction between Müller cells and photoreceptors, we injected either DL-α-aminoadipate or L-methionine sulfoximine–both inhibitors of glutamine synthetase–subretinally in rats. Following injection, the a-wave of the electroretinogram (ERG) was attenuated, and metabotropic glutamate receptor 5 (mGluR5) was activated. Selective antagonism of mGluR5 by 2-methyl-6-(phenylethynyl)-pyridine increased the ERG a-wave amplitude and also increased rhodopsin expression. Conversely, activation of mGluR5 by the agonist, (R,S)-2-chloro-5-hydroxyphenylglycine, decreased both the a-wave amplitude and rhodopsin expression, but upregulated expression of Gq alpha subunit and phospholipase C βIII. Overexpression of mGluR5 reduced the inward-rectifying potassium ion channel (Kir) current and decreased the expression of Kir4.1 and aquaporin-4 (AQP4). Further experiments indicated that mGluR5 formed a macromolecular complex with these two membrane channels. Lastly, increased expression of mGluR5 was found in Royal College of Surgeons rats–a model of retinitis pigmentosa (RP). Inhibition of mGluR5 in this model restored the amplitude of ERG features, and reduced the expression of glial fibrillary acidic protein. These results suggest that mGluR5 may be worth considering as a potential therapeutic target in RP.
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Affiliation(s)
- Jiaman Dai
- Bioengineering College, Chongqing University, Chongqing, 400040, China.,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, 400038, China
| | - Yan Fu
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, 400038, China.,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, 400038, China
| | - Yuxiao Zeng
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, 400038, China.,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, 400038, China
| | - Shiying Li
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, 400038, China. .,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, 400038, China.
| | - Zheng Qin Yin
- Bioengineering College, Chongqing University, Chongqing, 400040, China. .,Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, 400038, China. .,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, 400038, China.
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15
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Shen W, Yau B, Lee SR, Zhu L, Yam M, Gillies MC. Effects of Ranibizumab and Aflibercept on Human Müller Cells and Photoreceptors under Stress Conditions. Int J Mol Sci 2017; 18:ijms18030533. [PMID: 28257068 PMCID: PMC5372549 DOI: 10.3390/ijms18030533] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 02/24/2017] [Indexed: 11/16/2022] Open
Abstract
Anti-vascular endothelial growth factor (VEGF) therapy has revolutionized the treatment of retinal vascular diseases. However, constitutive VEGF also acts as a trophic factor on retinal nonvascular cells. We have studied the effects of aflibercept and ranibizumab on human Müller cells and photoreceptors exposed to starvation media containing various concentrations of glucose, with or without CoCl2-induced hypoxia. Cell survival was assessed by calcein-AM cell viability assays. Expression of heat shock proteins (Hsp) and redox proteins thioredoxin 1 and 2 (TRX1, TRX2) was studied by Western blots. The production of neurotrophic factors in Müller cells and interphotoreceptor retinoid-binding protein (IRBP) in photoreceptors was measured by enzymelinked immunosorbent assays. Aflibercept and ranibizumab did not affect the viability of both types of cells. Neither aflibercept nor ranibizumab affected the production of neurotrophic factors or expression of Hsp60 and Hsp90 in Müller cells. However, aflibercept but not ranibizumab affected the expression of Hsp60, Hsp9, TRX1 and TRX2 in photoreceptors. Aflibercept and ranibizumab both inhibited the production of IRBP in photoreceptors, aflibercept more so than ranibizumab. Our data indicates that the potential influence of aflibercept and ranibizumab on photoreceptors should be specifically monitored in clinical studies.
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Affiliation(s)
- Weiyong Shen
- Macula Research Group, Clinical Ophthalmology and Eye Health, Save Sight Institute, The University of Sydney, Sydney, NSW 2000, Australia.
| | - Belinda Yau
- Macula Research Group, Clinical Ophthalmology and Eye Health, Save Sight Institute, The University of Sydney, Sydney, NSW 2000, Australia.
| | - So-Ra Lee
- Macula Research Group, Clinical Ophthalmology and Eye Health, Save Sight Institute, The University of Sydney, Sydney, NSW 2000, Australia.
| | - Ling Zhu
- Macula Research Group, Clinical Ophthalmology and Eye Health, Save Sight Institute, The University of Sydney, Sydney, NSW 2000, Australia.
| | - Michelle Yam
- Macula Research Group, Clinical Ophthalmology and Eye Health, Save Sight Institute, The University of Sydney, Sydney, NSW 2000, Australia.
| | - Mark C Gillies
- Macula Research Group, Clinical Ophthalmology and Eye Health, Save Sight Institute, The University of Sydney, Sydney, NSW 2000, Australia.
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16
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Retinal Macroglial Responses in Health and Disease. BIOMED RESEARCH INTERNATIONAL 2016; 2016:2954721. [PMID: 27294114 PMCID: PMC4887628 DOI: 10.1155/2016/2954721] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 04/14/2016] [Indexed: 12/20/2022]
Abstract
Due to their permanent and close proximity to neurons, glial cells perform essential tasks for the normal physiology of the retina. Astrocytes and Müller cells (retinal macroglia) provide physical support to neurons and supplement them with several metabolites and growth factors. Macroglia are involved in maintaining the homeostasis of extracellular ions and neurotransmitters, are essential for information processing in neural circuits, participate in retinal glucose metabolism and in removing metabolic waste products, regulate local blood flow, induce the blood-retinal barrier (BRB), play fundamental roles in local immune response, and protect neurons from oxidative damage. In response to polyetiological insults, glia cells react with a process called reactive gliosis, seeking to maintain retinal homeostasis. When malfunctioning, macroglial cells can become primary pathogenic elements. A reactive gliosis has been described in different retinal pathologies, including age-related macular degeneration (AMD), diabetes, glaucoma, retinal detachment, or retinitis pigmentosa. A better understanding of the dual, neuroprotective, or cytotoxic effect of macroglial involvement in retinal pathologies would help in treating the physiopathology of these diseases. The extensive participation of the macroglia in retinal diseases points to these cells as innovative targets for new drug therapies.
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17
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Dominguez JM, Hu P, Caballero S, Moldovan L, Verma A, Oudit GY, Li Q, Grant MB. Adeno-Associated Virus Overexpression of Angiotensin-Converting Enzyme-2 Reverses Diabetic Retinopathy in Type 1 Diabetes in Mice. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:1688-700. [PMID: 27178803 DOI: 10.1016/j.ajpath.2016.01.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 01/07/2016] [Accepted: 01/19/2016] [Indexed: 12/17/2022]
Abstract
Angiotensin-converting enzyme (ACE)-2 is the primary enzyme of the vasoprotective axis of the renin angiotensin system that regulates the classic renin angiotensin system axis. We aimed to determine whether local retinal overexpression of adenoassociated virus (AAV)-ACE2 prevents or reverses diabetic retinopathy. Green fluorescent protein (GFP)-chimeric mice were generated to distinguish resident (retinal) from infiltrating bone marrow-derived inflammatory cells and were made diabetic using streptozotocin injections. Retinal digestion using trypsin was performed and acellular capillaries enumerated. Capillary occlusion by GFP(+) cells was used to measure leukostasis. Overexpression of ACE2 prevented (prevention cohort: untreated diabetic, 11.3 ± 1.4; ACE2 diabetic, 6.4 ± 0.9 per mm(2)) and partially reversed (reversal cohort: untreated diabetic, 15.7 ± 1.9; ACE2 diabetic, 6.5 ± 1.2 per mm(2)) the diabetes-associated increase of acellular capillaries and the increase of infiltrating inflammatory cells into the retina (F4/80(+)) (prevention cohort: untreated diabetic, 24.2 ± 6.7; ACE2 diabetic, 2.5 ± 1.6 per mm(2); reversal cohort: untreated diabetic, 56.8 ± 5.2; ACE2 diabetic, 5.6 ± 2.3 per mm(2)). In both study cohorts, intracapillary bone marrow-derived cells, indicative of leukostasis, were only observed in diabetic animals receiving control AAV injections. These results indicate that diabetic retinopathy, and possibly other diabetic microvascular complications, can be prevented and reversed by locally restoring the balance between the classic and vasoprotective renin angiotensin system.
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Affiliation(s)
- James M Dominguez
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, University of Florida, Gainesville, Florida; Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Ping Hu
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Sergio Caballero
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Leni Moldovan
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Amrisha Verma
- Department of Ophthalmology and Powell Gene Therapy Center, University of Florida College of Medicine, University of Florida, Gainesville, Florida
| | - Gavin Y Oudit
- Department of Medicine, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
| | - Qiuhong Li
- Department of Ophthalmology and Powell Gene Therapy Center, University of Florida College of Medicine, University of Florida, Gainesville, Florida
| | - Maria B Grant
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana.
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18
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Fernández-Sánchez L, Lax P, Campello L, Pinilla I, Cuenca N. Astrocytes and Müller Cell Alterations During Retinal Degeneration in a Transgenic Rat Model of Retinitis Pigmentosa. Front Cell Neurosci 2015; 9:484. [PMID: 26733810 PMCID: PMC4686678 DOI: 10.3389/fncel.2015.00484] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 11/30/2015] [Indexed: 12/29/2022] Open
Abstract
Purpose: Retinitis pigmentosa includes a group of progressive retinal degenerative diseases that affect the structure and function of photoreceptors. Secondarily to the loss of photoreceptors, there is a reduction in retinal vascularization, which seems to influence the cellular degenerative process. Retinal macroglial cells, astrocytes, and Müller cells provide support for retinal neurons and are fundamental for maintaining normal retinal function. The aim of this study was to investigate the evolution of macroglial changes during retinal degeneration in P23H rats. Methods: Homozygous P23H line-3 rats aged from P18 to 18 months were used to study the evolution of the disease, and SD rats were used as controls. Immunolabeling with antibodies against GFAP, vimentin, and transducin were used to visualize macroglial cells and cone photoreceptors. Results: In P23H rats, increased GFAP labeling in Müller cells was observed as an early indicator of retinal gliosis. At 4 and 12 months of age, the apical processes of Müller cells in P23H rats clustered in firework-like structures, which were associated with ring-like shaped areas of cone degeneration in the outer nuclear layer. These structures were not observed at 16 months of age. The number of astrocytes was higher in P23H rats than in the SD matched controls at 4 and 12 months of age, supporting the idea of astrocyte proliferation. As the disease progressed, astrocytes exhibited a deteriorated morphology and marked hypertrophy. The increase in the complexity of the astrocytic processes correlated with greater connexin 43 expression and higher density of connexin 43 immunoreactive puncta within the ganglion cell layer (GCL) of P23H vs. SD rat retinas. Conclusions: In the P23H rat model of retinitis pigmentosa, the loss of photoreceptors triggers major changes in the number and morphology of glial cells affecting the inner retina.
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Affiliation(s)
| | - Pedro Lax
- Department of Physiology, Genetics and Microbiology, University of Alicante Alicante, Spain
| | - Laura Campello
- Department of Physiology, Genetics and Microbiology, University of Alicante Alicante, Spain
| | - Isabel Pinilla
- Department of Ophthalmology, Aragon Institute for Health Research, Lozano Blesa University Hospital Zaragoza, Spain
| | - Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of AlicanteAlicante, Spain; Institute Ramón Margalef, University of AlicanteAlicante, Spain
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19
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Yao H, Wang T, Deng J, Liu D, Li X, Deng J. The development of blood-retinal barrier during the interaction of astrocytes with vascular wall cells. Neural Regen Res 2014; 9:1047-54. [PMID: 25206758 PMCID: PMC4146297 DOI: 10.4103/1673-5374.133169] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2014] [Indexed: 11/04/2022] Open
Abstract
Astrocytes are intimately involved in the formation and development of retinal vessels. Astrocyte dysfunction is a major cause of blood-retinal barrier injury and other retinal vascular diseases. In this study, the development of the retinal vascular system and the formation of the blood-retinal barrier in mice were investigated using immunofluorescence staining, gelatin-ink perfusion, and transmission electron microscopy. The results showed that the retinal vascular system of mice develops from the optic disc after birth, and radiates out gradually to cover the entire retina, taking the papilla optica as the center. First, the superficial vasculature is formed on the inner retinal layer; then, the vasculature extends into the inner and outer edges of the retinal inner nuclear layer, forming the deep vasculature that is parallel to the superficial vasculature. The blood-retinal barrier is mainly composed of endothelium, basal lamina and the end-feet of astrocytes, which become mature during mouse development. Initially, the naive endothelial cells were immature with few organelles and many microvilli. The basal lamina was uniform in thickness, and the glial end-feet surrounded the outer basal lamina incompletely. In the end, the blood-retinal barrier matures with smooth endothelia connected through tight junctions, relatively thin and even basal lamina, and relatively thin glial cell end-feet. These findings indicate that the development of the vasculature in the retina follows the rules of "center to periphery" and "superficial layer to deep layers". Its development and maturation are spatially and temporally consistent with the functional performance of retinal neurons and photosensitivity. The blood-retinal barrier gradually becomes mature via the process of interactions between astrocytes and blood vessel cells.
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Affiliation(s)
- Huanling Yao
- Institute of Neurobiology, College of Life Science, Henan University, Kaifeng, Henan Province, China
| | - Tianshi Wang
- Institute of Neurobiology, College of Life Science, Henan University, Kaifeng, Henan Province, China
| | - Jiexin Deng
- Institute of Neurobiology, College of Life Science, Henan University, Kaifeng, Henan Province, China
| | - Ding Liu
- Institute of Neurobiology, College of Life Science, Henan University, Kaifeng, Henan Province, China
| | - Xiaofei Li
- Institute of Neurobiology, College of Life Science, Henan University, Kaifeng, Henan Province, China
| | - Jinbo Deng
- Institute of Neurobiology, College of Life Science, Henan University, Kaifeng, Henan Province, China
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Shen W, Chung SH, Irhimeh MR, Li S, Lee SR, Gillies MC. Systemic administration of erythropoietin inhibits retinopathy in RCS rats. PLoS One 2014; 9:e104759. [PMID: 25119659 PMCID: PMC4132022 DOI: 10.1371/journal.pone.0104759] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 07/12/2014] [Indexed: 12/17/2022] Open
Abstract
Objective Royal College of Surgeons (RCS) rats develop vasculopathy as photoreceptors degenerate. The aim of this study was to examine the effect of erythropoietin (EPO) on retinopathy in RCS rats. Methods Fluorescein angiography was used to monitor retinal vascular changes over time. Changes in retinal glia and vasculature were studied by immunostaining. To study the effects of EPO on retinal pathology, EPO (5000 IU/kg) was injected intraperitoneally in 14 week old normal and RCS rats twice a week for 4 weeks. Changes in the retinal vasculature, glia and microglia, photoreceptor apoptosis, differential expression of p75 neurotrophin receptor (p75NTR), pro-neurotrophin 3 (pro-NT3), tumour necrosis factor-α (TNFα), pigment epithelium derived factor (PEDF) and vascular endothelial growth factor-A (VEGF-A), the production of CD34+ cells and mobilization of CD34+/VEGF-R2+ cells as well as recruitment of CD34+ cells into the retina were examined after EPO treatment. Results RCS rats developed progressive capillary dropout and subretinal neovascularization which were accompanied by retinal gliosis. Systemic administration of EPO stabilized the retinal vasculature and inhibited the development of focal vascular lesions. Further studies showed that EPO modulated retinal gliosis, attenuated photoreceptor apoptosis and p75NTR and pro-NT3 upregulation, promoted the infiltration of ramified microglia and stimulated VEGF-A expression but had little effect on TNFα and PEDF expression. EPO stimulated the production of red and white blood cells and CD34+ cells along with effective mobilization of CD34+/VEGF-R2+ cells. Immunofluorescence study demonstrated that EPO enhanced the recruitment of CD34+ cells into the retina. Conclusions Our results suggest that EPO has therapeutic potentials in treatment of neuronal and vascular pathology in retinal disease. The protective effects of EPO on photoreceptors and the retinal vasculature may involve multiple mechanisms including regulation of retinal glia and microglia, inhibition of p75NTR-pro-NT3 signaling together with stimulation of production and mobilization of bone marrow derived cells.
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Affiliation(s)
- Weiyong Shen
- Save Sight Institute, the University of Sydney, Sydney, Australia
| | - Sook H Chung
- Save Sight Institute, the University of Sydney, Sydney, Australia
| | | | - Shiying Li
- Save Sight Institute, the University of Sydney, Sydney, Australia; Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, China
| | - So-Ra Lee
- Save Sight Institute, the University of Sydney, Sydney, Australia
| | - Mark C Gillies
- Save Sight Institute, the University of Sydney, Sydney, Australia
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Muto T, Tien T, Kim D, Sarthy VP, Roy S. High glucose alters Cx43 expression and gap junction intercellular communication in retinal Müller cells: promotes Müller cell and pericyte apoptosis. Invest Ophthalmol Vis Sci 2014; 55:4327-37. [PMID: 24938518 DOI: 10.1167/iovs.14-14606] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
PURPOSE To investigate whether high glucose (HG) alters connexin 43 (Cx43) expression and gap junction intercellular communication (GJIC) activity in retinal Müller cells, and promotes Müller cell and pericyte loss. METHODS Retinal Müller cells (rMC-1) and cocultures of rMC-1 and retinal pericytes were grown in normal (N) or HG (30 mM glucose) medium. Additionally, rMC-1 transfected with Cx43 small interfering RNA (siRNA) were grown as cocultures with pericytes, and rMC-1 transfected with Cx43 plasmid were grown in HG. Expression of Cx43 was determined by Western blotting and immunostaining and GJIC was assessed by scrape-loading dye transfer (SLDT) technique. Apoptosis was analyzed by TUNEL or differential staining assay, and Akt activation by assessing Akt phosphorylation. RESULTS In monocultures of rMC-1 and cocultures of rMC-1 and pericytes, Cx43 protein level, number of Cx43 plaques, GJIC, and Akt phosphorylation were significantly reduced in HG medium. Number of TUNEL-positive cells was also significantly increased in rMC-1 monocultures and in rMC-1 and pericyte cocultures grown in HG medium. Importantly, when rMC-1 transfected with Cx43 siRNA were grown as cocultures with pericytes, a significant decrease in GJIC, and increase in TUNEL-positive cells was observed, concomitant with decreased Akt phosphorylation. Upregulation of Cx43 rescued rMC-1 from HG-induced apoptosis. CONCLUSIONS Gap junction communication between Müller cells and pericytes is essential for their survival. Downregulation of Cx43 that is HG induced and impairment of GJIC activity in Müller cells contributes to loss of glial and vascular cells associated with the pathogenesis of diabetic retinopathy.
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Affiliation(s)
- Tetsuya Muto
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Thomas Tien
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Dongjoon Kim
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Vijay P Sarthy
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
| | - Sayon Roy
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
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22
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Byrne LC, Khalid F, Lee T, Zin EA, Greenberg KP, Visel M, Schaffer DV, Flannery JG. AAV-mediated, optogenetic ablation of Müller Glia leads to structural and functional changes in the mouse retina. PLoS One 2013; 8:e76075. [PMID: 24086689 PMCID: PMC3785414 DOI: 10.1371/journal.pone.0076075] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 08/20/2013] [Indexed: 11/18/2022] Open
Abstract
Müller glia, the primary glial cell in the retina, provide structural and metabolic support for neurons and are essential for retinal integrity. Müller cells are closely involved in many retinal degenerative diseases, including macular telangiectasia type 2, in which impairment of central vision may be linked to a primary defect in Müller glia. Here, we used an engineered, Müller-specific variant of AAV, called ShH10, to deliver a photo-inducibly toxic protein, KillerRed, to Müller cells in the mouse retina. We characterized the results of specific ablation of these cells on visual function and retinal structure. ShH10-KillerRed expression was obtained following intravitreal injection and eyes were then irradiated with green light to induce toxicity. Induction of KillerRed led to loss of Müller cells and a concomitant decrease of Müller cell markers glutamine synthetase and cellular retinaldehyde-binding protein, reduction of rhodopsin and cone opsin, and upregulation of glial fibrillary acidic protein. Loss of Müller cells also resulted in retinal disorganization, including thinning of the outer nuclear layer and the photoreceptor inner and outer segments. High resolution imaging of thin sections revealed displacement of photoreceptors from the ONL, formation of rosette-like structures and the presence of phagocytic cells. Furthermore, Müller cell ablation resulted in increased area and volume of retinal blood vessels, as well as the formation of tortuous blood vessels and vascular leakage. Electrophysiologic measures demonstrated reduced retinal function, evident in decreased photopic and scotopic electroretinogram amplitudes. These results show that loss of Müller cells can cause progressive retinal degenerative disease, and suggest that AAV delivery of an inducibly toxic protein in Müller cells may be useful to create large animal models of retinal dystrophies.
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Affiliation(s)
- Leah C. Byrne
- Department of Molecular and Cellular Biology and The Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
| | - Fakhra Khalid
- Department of Molecular and Cellular Biology and The Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
| | - Trevor Lee
- Department of Molecular and Cellular Biology and The Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
| | - Emilia A. Zin
- Department of Molecular and Cellular Biology and The Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
| | | | - Meike Visel
- Department of Molecular and Cellular Biology and The Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
| | - David V. Schaffer
- Department of Chemical Engineering, Department of Bioengineering, and The Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
| | - John G. Flannery
- Department of Molecular and Cellular Biology and The Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
- * E-mail:
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23
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Conditional Müllercell ablation causes independent neuronal and vascular pathologies in a novel transgenic model. J Neurosci 2013; 32:15715-27. [PMID: 23136411 DOI: 10.1523/jneurosci.2841-12.2012] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Müller cells are the major glia of the retina that serve numerous functions essential to retinal homeostasis, yet the contribution of Müller glial dysfunction to retinal diseases remains largely unknown. We have developed a transgenic model using a portion of the regulatory region of the retinaldehyde binding protein 1 gene for conditional Müller cell ablation and the consequences of primary Müller cell dysfunction have been studied in adult mice. We found that selective ablation of Müller cells led to photoreceptor apoptosis, vascular telangiectasis, blood-retinal barrier breakdown and, later, intraretinal neovascularization. These changes were accompanied by impaired retinal function and an imbalance between vascular endothelial growth factor-A (VEGF-A) and pigment epithelium-derived factor. Intravitreal injection of ciliary neurotrophic factor inhibited photoreceptor injury but had no effect on the vasculopathy. Conversely, inhibition of VEGF-A activity attenuated vascular leak but did not protect photoreceptors. Our findings show that Müller glial deficiency may be an important upstream cause of retinal neuronal and vascular pathologies in retinal diseases. Combined neuroprotective and anti-angiogenic therapies may be required to treat Müller cell deficiency in retinal diseases and in other parts of the CNS associated with glial dysfunction.
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24
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Bringmann A, Grosche A, Pannicke T, Reichenbach A. GABA and Glutamate Uptake and Metabolism in Retinal Glial (Müller) Cells. Front Endocrinol (Lausanne) 2013; 4:48. [PMID: 23616782 PMCID: PMC3627989 DOI: 10.3389/fendo.2013.00048] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 04/04/2013] [Indexed: 12/11/2022] Open
Abstract
Müller cells, the principal glial cells of the retina, support the synaptic activity by the uptake and metabolization of extracellular neurotransmitters. Müller cells express uptake and exchange systems for various neurotransmitters including glutamate and γ-aminobutyric acid (GABA). Müller cells remove the bulk of extracellular glutamate in the inner retina and contribute to the glutamate clearance around photoreceptor terminals. By the uptake of glutamate, Müller cells are involved in the shaping and termination of the synaptic activity, particularly in the inner retina. Reactive Müller cells are neuroprotective, e.g., by the clearance of excess extracellular glutamate, but may also contribute to neuronal degeneration by a malfunctioning or even reversal of glial glutamate transporters, or by a downregulation of the key enzyme, glutamine synthetase. This review summarizes the present knowledge about the role of Müller cells in the clearance and metabolization of extracellular glutamate and GABA. Some major pathways of GABA and glutamate metabolism in Müller cells are described; these pathways are involved in the glutamate-glutamine cycle of the retina, in the defense against oxidative stress via the production of glutathione, and in the production of substrates for the neuronal energy metabolism.
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Affiliation(s)
- Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of LeipzigLeipzig, Germany
| | - Antje Grosche
- Paul Flechsig Institute of Brain Research, Faculty of Medicine, University of LeipzigLeipzig, Germany
| | - Thomas Pannicke
- Paul Flechsig Institute of Brain Research, Faculty of Medicine, University of LeipzigLeipzig, Germany
| | - Andreas Reichenbach
- Paul Flechsig Institute of Brain Research, Faculty of Medicine, University of LeipzigLeipzig, Germany
- *Correspondence: Andreas Reichenbach, Paul Flechsig Institute of Brain Research, University of Leipzig, Jahnallee 59, D-04109 Leipzig, Germany. e-mail:
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25
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Kielczewski JL, Li Calzi S, Shaw LC, Cai J, Qi X, Ruan Q, Wu L, Liu L, Hu P, Chan-Ling T, Mames RN, Firth S, Baxter RC, Turowski P, Busik JV, Boulton ME, Grant MB. Free insulin-like growth factor binding protein-3 (IGFBP-3) reduces retinal vascular permeability in association with a reduction of acid sphingomyelinase (ASMase). Invest Ophthalmol Vis Sci 2011; 52:8278-86. [PMID: 21931131 DOI: 10.1167/iovs.11-8167] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
PURPOSE To examine the effect of free insulin-like growth factor (IGF) binding protein-3 (IGFBP-3), independent of the effect of insulin-like growth factors, in modulating retinal vascular permeability. METHODS We assessed the ability of a form of IGFBP-3 that does not bind IGF-1 (IGFBP-3NB), to regulate the blood retinal barrier (BRB) using two distinct experimental mouse models, laser-induced retinal vessel injury and vascular endothelial growth factor (VEGF)-induced retinal vascular permeability. Additionally, in vitro studies were conducted. In the animal models, BRB permeability was quantified by intravenous injection of fluorescein labeled serum albumin followed by digital confocal image analysis of retinal flat-mounts. Claudin-5 and vascular endothelial-cadherin (VE-cadherin) localization at interendothelial junctions was studied by immunofluorescence. In vitro changes in transendothelial electrical resistance (TEER) and flux of fluorescent dextran in bovine retinal endothelial monolayers (BREC) were measured after IGFBP-3NB treatment. Acid (ASMase) and neutral (NSMase) sphingomyelinase mRNA levels and activity were measured in mouse retinas. RESULTS Four days postinjury, laser-injured mouse retinas injected with IGFBP-3NB plasmid demonstrated reduced vascular permeability compared with retinas of laser-injured mouse retinas injected with control plasmid. IGFBP-3NB administration resulted in a significant decrease in laser injury-associated increases in ASMase and NSMase mRNA and activity when compared with laser alone treated mice. In vivo, intravitreal injection of IGFBP-3NB reduced vascular leakage associated with intravitreal VEGF injection. IGFBP-3NB partially restored VEGF-induced in vivo permeability and dissociation of claudin-5 and VE-cadherin at junctional complexes. When IGFBP-3NB was applied basally to bovine retinal endothelial cells (BREC) in vitro, TEER increased and macromolecular flux decreased. CONCLUSIONS Intravitreal administration of IGFBP-3NB preserves junctional integrity in the presence of VEGF or laser injury by reducing BRB permeability in part by modulating sphingomyelinase levels.
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Affiliation(s)
- Jennifer L Kielczewski
- Departments of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida 32610-0267, USA
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