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Husain S, Leveckis R. Pharmacological regulation of HIF-1α, RGC death, and glaucoma. Curr Opin Pharmacol 2024; 77:102467. [PMID: 38896924 DOI: 10.1016/j.coph.2024.102467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 04/19/2024] [Accepted: 05/22/2024] [Indexed: 06/21/2024]
Abstract
Hypoxia can regulate oxygen-sensitive pathways that could be neuroprotective to compensate for the detrimental effects of low oxygen. However, prolonged hypoxia can activate neurodegenerative pathways. HIF-1α is upregulated/stabilized in hypoxic conditions, promoting alteration of gene expression, and ultimately leading to cell-death. Therefore, regulation of HIF-1α expression pharmacologically is a vital approach to mitigate cell death. In this review, we provide information showing the role of HIF-1α and its associated pathways in ocular retinopathies. We also discuss the beneficial roles of HIF-1α inhibitor, KC7F2, in ocular pathologies. Finally, we provided our own data demonstrating RGC neuroprotection by KC7F2 in glaucomatous animals.
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Affiliation(s)
- Shahid Husain
- Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, SC 29425, USA.
| | - Ryan Leveckis
- Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, SC 29425, USA
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2
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Atalor RE, Dieckmann BW, Penn JS, Uddin MDI. Method to Regulate Monocyte Function by Silencing HIF-1α mRNA in a Model of Retinal Neovascularization. ACS APPLIED NANO MATERIALS 2023; 6:22939-22946. [PMID: 38148985 PMCID: PMC10749564 DOI: 10.1021/acsanm.3c04300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/15/2023] [Accepted: 11/17/2023] [Indexed: 12/28/2023]
Abstract
Circulating monocytes migrate into the retina in response to inflammation and neovascularization. Furthermore, under inflammatory conditions such as diabetes, healthy monocytes become activated in the circulation. However, the contribution of activated monocytes to neovascularization is largely unknown. HIF-1α has been shown to contribute to the pathogenesis of neovascularization. We describe here the synthesis of a hybrid nanomaterial for targeted delivery and gene silencing in activated monocytes that are associated with pathological neovascularization. To test the gene silencing ability of AS-shRNA-lipids in vitro, we used the probe to inhibit HIF-1α mRNA induced in mouse monocytes by exposing them to hypoxia. In addition, we tested AS-shRNA-lipids for inhibition of neovascularization in vivo using the mouse model of oxygen-induced retinopathy (OIR). Significant reduction of neovascularization was achieved in mouse OIR by targeting activated monocytes using intraperitoneal injections of AS-shRNA-lipids. Expression of HIF-1α and CD14 mRNA were both inhibited in circulating cells, suggesting normalization of the activated monocytes in P17 OIR animals treated with AS-shRNA-lipids. We hypothesized that inhibition of HIF-1α mRNA in activated monocytes may have a direct impact on VEGF expression in the retinal tissues in vivo. We observed that VEGF mRNA expression was inhibited in P17 retinal tissues after systemic treatment with HIF-1α-targeted AS-shRNA-lipids. These findings may provide a framework for a strategy to inhibit retinal neovascularization by targeting circulating activated monocytes.
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Affiliation(s)
- Rita E. Atalor
- Department
of Ophthalmology and Visual Sciences, Vanderbilt
University School of Medicine, Nashville, Tennessee 37232, United States
| | - Blake W. Dieckmann
- Department
of Ophthalmology and Visual Sciences, Vanderbilt
University School of Medicine, Nashville, Tennessee 37232, United States
| | - John S. Penn
- Department
of Ophthalmology and Visual Sciences, Vanderbilt
University School of Medicine, Nashville, Tennessee 37232, United States
| | - MD Imam Uddin
- Department
of Ophthalmology and Visual Sciences, Vanderbilt
University School of Medicine, Nashville, Tennessee 37232, United States
- Department
of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, United States
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3
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Edgar KS, Cunning C, Gardiner TA, McDonald DM. BH4 supplementation reduces retinal cell death in ischaemic retinopathy. Sci Rep 2023; 13:21292. [PMID: 38042898 PMCID: PMC10693630 DOI: 10.1038/s41598-023-48167-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 11/22/2023] [Indexed: 12/04/2023] Open
Abstract
Dysregulation of nitric oxide (NO) production can cause ischaemic retinal injury and result in blindness. How this dysregulation occurs is poorly understood but thought to be due to an impairment in NO synthase function (NOS) and nitro-oxidative stress. Here we investigated the possibility of correcting this defective NOS activity by supplementation with the cofactor tetrahydrobiopterin, BH4. Retinal ischaemia was examined using the oxygen-induced retinopathy model and BH4 deficient Hph-1 mice used to establish the relationship between NOS activity and BH4. Mice were treated with the stable BH4 precursor sepiapterin at the onset of hypoxia and their retinas assessed 48 h later. HPLC analysis confirmed elevated BH4 levels in all sepiapterin supplemented groups and increased NOS activity. Sepiapterin treatment caused a significant decrease in neuronal cell death in the inner nuclear layer that was most notable in WT animals and was associated with significantly diminished superoxide and local peroxynitrite formation. Interestingly, sepiapterin also increased inflammatory cytokine levels but not microglia cell number. BH4 supplementation by sepiapterin improved both redox state and neuronal survival during retinal ischaemia, in spite of a paradoxical increase in inflammatory cytokines. This implicates nitro-oxidative stress in retinal neurones as the cytotoxic element in ischaemia, rather than enhanced pro-inflammatory signalling.
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Affiliation(s)
- Kevin S Edgar
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, 97 Lisburn Road, BT9 7BL, UK
| | - Ciara Cunning
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, 97 Lisburn Road, BT9 7BL, UK
| | - Tom A Gardiner
- School of Medicine, Dentistry and Biomedical Sciences, Centre for Biomedical Sciences Education, Queen's University Belfast, Belfast, UK
| | - Denise M McDonald
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, 97 Lisburn Road, BT9 7BL, UK.
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4
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Pauleikhoff L, Boneva S, Boeck M, Schlecht A, Schlunck G, Agostini H, Lange C, Wolf J. Transcriptional Comparison of Human and Murine Retinal Neovascularization. Invest Ophthalmol Vis Sci 2023; 64:46. [PMID: 38153746 PMCID: PMC10756240 DOI: 10.1167/iovs.64.15.46] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/30/2023] [Indexed: 12/29/2023] Open
Abstract
Purpose Retinal neovascularization (RNV) is the leading cause of vision loss in diseases like proliferative diabetic retinopathy (PDR). A significant failure rate of current treatments indicates the need for novel treatment targets. Animal models are crucial in this process, but current diabetic retinopathy models do not develop RNV. Although the nondiabetic oxygen-induced retinopathy (OIR) mouse model is used to study RNV development, it is largely unknown how closely it resembles human PDR. Methods We therefore performed RNA sequencing on murine (C57BL/6J) OIR retinas (n = 14) and human PDR RNV membranes (n = 7) extracted during vitrectomy, each with reference to control tissue (n=13/10). Differentially expressed genes (DEG) and associated biological processes were analyzed and compared between human and murine RNV to assess molecular overlap and identify phylogenetically conserved factors. Results In total, 213 murine- and 1223 human-specific factors were upregulated with a small overlap of 94 DEG (7% of human DEG), although similar biological processes such as angiogenesis, regulation of immune response, and extracellular matrix organization were activated in both species. Phylogenetically conserved mediators included ANGPT2, S100A8, MCAM, EDNRA, and CCR7. Conclusions Even though few individual genes were upregulated simultaneously in both species, similar biological processes appeared to be activated. These findings demonstrate the potential and limitations of the OIR model to study human PDR and identify phylogenetically conserved potential treatment targets for PDR.
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Affiliation(s)
- Laurenz Pauleikhoff
- Eye Center, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Ophthalmology, Amsterdam University Medical Centers, Amsterdam, the Netherlands
| | - Stefaniya Boneva
- Eye Center, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Myriam Boeck
- Eye Center, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Anja Schlecht
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Günther Schlunck
- Eye Center, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Hansjürgen Agostini
- Eye Center, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Clemens Lange
- Eye Center at St. Franziskus Hospital, Münster, Germany
| | - Julian Wolf
- Eye Center, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Molecular Surgery Laboratory, Department of Ophthalmology, Byers Eye Institute, Stanford University, Palo Alto, California, United States
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5
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Jiao W, Li W, Li T, Feng T, Wu C, Zhao D. Induced pluripotent stem cell-derived extracellular vesicles overexpressing SFPQ protect retinal Müller cells against hypoxia-induced injury. Cell Biol Toxicol 2023; 39:2647-2663. [PMID: 36790503 DOI: 10.1007/s10565-023-09793-x] [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: 05/20/2022] [Accepted: 01/17/2023] [Indexed: 02/16/2023]
Abstract
Splicing factor proline/glutamine-rich (SFPQ) is expressed in induced pluripotent stem cells (iPSCs), which are reported to orchestrate hypoxic injury responses and release extracellular vesicles (EVs). Therefore, this study sought to explore the role of iPSC-derived EVs carrying SFPQ in hypoxia-induced injury to retinal Müller cells. We induced oxygen-glucose deprivation/reoxygenation (OGD/R) in Müller cells. SFPQ was overexpressed or knocked down in iPSCs, from which EVs were extracted. Müller cells were co-cultured with EVs, and the results indicated that SFPQ protein was transferred into retinal Müller cells by iPSC-derived EVs. We identified an interaction of SFPQ with HDAC1 in retinal Müller cells. Specifically, SFPQ recruited HDAC1 to downregulate HIF-2α by regulating its acetylation. The in vitro studies suggested that iPSC-derived EVs, SFPQ or HDAC1 overexpression, or HIF-2α silencing diminished cell injury and apoptosis but elevated proliferation in retinal Müller cells. The in vivo studies indicated that iPSC-derived EVs containing SFPQ curtailed apoptosis of retinal Müller cells, thus alleviating retinal ischemia/reperfusion (I/R) injury of rat model. Taken together, iPSC-derived EVs containing SFPQ upregulated HDAC1 to attenuate OGD/R-induced Müller cell injury via downregulation of HIF-2α.
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Affiliation(s)
- Wenjun Jiao
- Department of Geriatric Endocrinology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China
| | - Weifang Li
- Department of Geriatric Endocrinology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China
| | - Tianyi Li
- Department of Geriatric Endocrinology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China
| | - Tao Feng
- Department of Geriatric Endocrinology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China
| | - Cong Wu
- Department of Geriatric Endocrinology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China
| | - Di Zhao
- Department of Endocrinology, the First Affiliated Hospital of Zhengzhou University, No. 1, Jianshe East Road, Zhengzhou, 450052, People's Republic of China.
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6
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Cristante E, Liyanage SE, Smith AJ, Ali RR, Bainbridge JWB. Role of HIF1α and HIF2α in Cre Recombinase-Induced Retinal Pigment Epithelium Pathology and Its Secondary Effect on Choroidal Neovascularization. THE AMERICAN JOURNAL OF PATHOLOGY 2023; 193:1694-1705. [PMID: 37330004 DOI: 10.1016/j.ajpath.2023.05.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 05/09/2023] [Accepted: 05/19/2023] [Indexed: 06/19/2023]
Abstract
CreTrp1 mice are widely used for conditional retinal pigment epithelium (RPE) gene function studies. Like other Cre/LoxP models, phenotypes in CreTrp1 mice can be affected by Cre-mediated cellular toxicity, leading to RPE dysfunction, altered morphology and atrophy, activation of innate immunity, and consequent impairment of photoreceptor function. These effects are common among the age-related alterations of RPE that feature in early/intermediate forms of age-related macular degeneration. This article characterizes Cre-mediated pathology in the CreTrp1 line to elucidate the impact of RPE degeneration on both developmental and pathologic choroidal neovascularization. Nonredundant roles of the two major components of the hypoxia-inducible factor (HIF) family of transcription regulators, HIF1α and HIF2α, were identified. Genetic ablation of Hif1a protected against Cre-induced degeneration of RPE and choroid, whereas ablation of Hif2a exacerbated this degeneration. Furthermore, HIF1α deficiency protected CreTrp1 mice against laser-induced choroidal neovascularization, whereas HIF2α deficiency exacerbated the phenotype. Cre-mediated degeneration of the RPE in CreTrp1 mice offers an opportunity to investigate the impact of hypoxia signaling in the context of RPE degeneration. These findings indicate that HIF1α promotes Cre recombinase-mediated RPE degeneration and laser-induced choroidal neovascularization, whereas HIF2α is protective.
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Affiliation(s)
| | | | - Alexander J Smith
- Centre for Cell and Gene Therapy, King's College London, Guy's Hospital, London, United Kingdom
| | - Robin R Ali
- Centre for Cell and Gene Therapy, King's College London, Guy's Hospital, London, United Kingdom
| | - James W B Bainbridge
- UCL Institute of Ophthalmology London, United Kingdom; NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom.
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7
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Fevereiro-Martins M, Marques-Neves C, Guimarães H, Bicho M. Retinopathy of prematurity: A review of pathophysiology and signaling pathways. Surv Ophthalmol 2023; 68:175-210. [PMID: 36427559 DOI: 10.1016/j.survophthal.2022.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 11/15/2022] [Accepted: 11/18/2022] [Indexed: 11/25/2022]
Abstract
Retinopathy of prematurity (ROP) is a vasoproliferative disorder of the retina and a leading cause of visual impairment and childhood blindness worldwide. The disease is characterized by an early stage of retinal microvascular degeneration, followed by neovascularization that can lead to subsequent retinal detachment and permanent visual loss. Several factors play a key role during the different pathological stages of the disease. Oxidative and nitrosative stress and inflammatory processes are important contributors to the early stage of ROP. Nitric oxide synthase and arginase play important roles in ischemia/reperfusion-induced neurovascular degeneration. Destructive neovascularization is driven by mediators of the hypoxia-inducible factor pathway, such as vascular endothelial growth factor and metabolic factors (succinate). The extracellular matrix is involved in hypoxia-induced retinal neovascularization. Vasorepulsive molecules (semaphorin 3A) intervene preventing the revascularization of the avascular zone. This review focuses on current concepts about signaling pathways and their mediators, involved in the pathogenesis of ROP, highlighting new potentially preventive and therapeutic modalities. A better understanding of the intricate molecular mechanisms underlying the pathogenesis of ROP should allow the development of more effective and targeted therapeutic agents to reduce aberrant vasoproliferation and facilitate physiological retinal vascular development.
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Affiliation(s)
- Mariza Fevereiro-Martins
- Laboratório de Genética and Grupo Ecogenética e Saúde Humana, Instituto de Saúde Ambiental, Faculdade de Medicina, Universidade de Lisboa, Portugal; Instituto de Investigação Científica Bento da Rocha Cabral, Lisboa, Portugal; Departamento de Oftalmologia, Hospital Cuf Descobertas, Lisboa, Portugal.
| | - Carlos Marques-Neves
- Centro de Estudos das Ci.¼ncias da Visão, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal; Grupo Ecogenética e Saúde Humana, Instituto de Saúde Ambiental, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.
| | - Hercília Guimarães
- Departamento de Ginecologia-Obstetrícia e Pediatria, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.
| | - Manuel Bicho
- Laboratório de Genética and Grupo Ecogenética e Saúde Humana, Instituto de Saúde Ambiental, Faculdade de Medicina, Universidade de Lisboa, Portugal; Instituto de Investigação Científica Bento da Rocha Cabral, Lisboa, Portugal.
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8
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Pitale PM, Shen G, Sigireddi RR, Polo-Prieto M, Park YH, Gibson SE, Westenskow PD, Channa R, Frankfort BJ. Selective vulnerability of the intermediate retinal capillary plexus precedes retinal ganglion cell loss in ocular hypertension. Front Cell Neurosci 2022; 16:1073786. [PMID: 36545655 PMCID: PMC9760765 DOI: 10.3389/fncel.2022.1073786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 11/15/2022] [Indexed: 12/08/2022] Open
Abstract
Introduction: Glaucoma, a disease of retinal ganglion cell (RGC) injury and potentially devastating vision loss, is associated with both ocular hypertension (OHT) and reduced ocular blood flow. However, the relationship between OHT and retinal capillary architecture is not well understood. In this project, we studied microvasculature damage in mice exposed to mild levels of induced OHT. Methods: Mild OHT was induced with the microbead model for 2 weeks. At this time point, some retinas were immunostained with CD31 (endothelium), Collagen IV (basement membrane), and RBPMS (RGCs) for z-stack confocal microscopy. We processed these confocal images to distinguish the three retinal capillary plexi (superficial, intermediate, and deep). We manually counted RGC density, analyzed vascular complexity, and identified topographical and spatial vascular features of the retinal capillaries using a combination of novel manual and automated workflows. Other retinas were dissociated and immunopanned to isolate RGCs and amacrine cells (ACs) for hypoxia gene array analysis. Results: RGC counts were normal but there was decreased overall retinal capillary complexity. This reduced complexity could be explained by abnormalities in the intermediate retinal capillary plexus (IRCP) that spared the other plexi. Capillary junction density, vessel length, and vascular area were all significantly reduced, and the number of acellular capillaries was dramatically increased. ACs, which share a neurovascular unit (NVU) with the IRCP, displayed a marked increase in the relative expression of many hypoxia-related genes compared to RGCs from the same preparations. Discussion: We have discovered a rapidly occurring, IRCP-specific, OHT-induced vascular phenotype that precedes RGC loss. AC/IRCP NVU dysfunction may be a mechanistic link for early vascular remodeling in glaucoma.
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Affiliation(s)
- Priyamvada M. Pitale
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Guofu Shen
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Rohini R. Sigireddi
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Maria Polo-Prieto
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Yong H. Park
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Solomon E. Gibson
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States,Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
| | - Peter D. Westenskow
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Roomasa Channa
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, United States
| | - Benjamin J. Frankfort
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States,Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States,*Correspondence: Benjamin J. Frankfort
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9
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Chidlow G, Chan WO, Wood JPM, Casson RJ. Investigations into photoreceptor energy metabolism during experimental retinal detachment. Front Cell Neurosci 2022; 16:1036834. [PMID: 36467607 PMCID: PMC9716104 DOI: 10.3389/fncel.2022.1036834] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 11/01/2022] [Indexed: 08/27/2023] Open
Abstract
Retinal detachment is a sight-threatening disorder, which occurs when the photoreceptors are separated from their vascular supply. The aim of the present study was to shed light on photoreceptor energy metabolism during experimental detachment in rats. Retinal detachment was induced in the eyes of rats via subretinal injection of sodium hyaluronate. Initially, we investigated whether detachment caused hypoxia within photoreceptors, as evaluated by the exogenous and endogenous biomarkers pimonidazole and HIF-1α, as well as by qPCR analysis of HIF target genes. The results showed no unequivocal staining for pimonidazole or HIF-1α within any detached retina, nor upregulation of HIF target genes, suggesting that any reduction in pO2 is of insufficient magnitude to produce hypoxia-induced covalent protein adducts or HIF-1α stabilisation. Subsequently, we analysed expression of cellular bioenergetic enzymes in photoreceptors during detachment. We documented loss of mitochondrial, and downregulation of glycolytic enzymes during detachment, indicating that photoreceptors have reduced energetic requirements and/or capacity. Given that detachment did not cause widespread hypoxia, but did result in downregulated expression of bioenergetic enzymes, we hypothesised that substrate insufficiency may be critical in terms of pathogenesis, and that boosting metabolic inputs may preserve photoreceptor bioenergetic production and, protect against their degeneration. Thus, we tested whether supplementation with the bioavailable energy substrate pyruvate mitigated rod and cone injury and degeneration. Despite protecting photoreceptors in culture from nutrient deprivation, pyruvate failed to protect against apoptotic death of rods, loss of cone opsins, and loss of inner segment mitochondria, in situ, when evaluated at 3 days after detachment. The regimen was also ineffective against cumulative photoreceptor deconstruction and degeneration when evaluated after 4 weeks. Retinal metabolism, particularly the bioenergetic profiles and pathological responses of the various cellular subtypes still presents a considerable knowledge gap that has important clinical consequences. While our data do not support the use of pyruvate supplementation as a means of protecting detached photoreceptors, they do provide a foundation and motivation for future research in this area.
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Affiliation(s)
- Glyn Chidlow
- Ophthalmic Research Laboratories, Discipline of Ophthalmology and Visual Sciences, University of Adelaide, Adelaide, SA, Australia
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10
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Ocular Hypertension Results in Hypoxia within Glia and Neurons throughout the Visual Projection. Antioxidants (Basel) 2022; 11:antiox11050888. [PMID: 35624752 PMCID: PMC9137916 DOI: 10.3390/antiox11050888] [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: 03/25/2022] [Revised: 04/24/2022] [Accepted: 04/27/2022] [Indexed: 12/03/2022] Open
Abstract
The magnitude and duration of hypoxia after ocular hypertension (OHT) has been a matter of debate due to the lack of tools to accurately report hypoxia. In this study, we established a topography of hypoxia in the visual pathway by inducing OHT in mice that express a fusion protein comprised of the oxygen-dependent degradation (ODD) domain of HIF-1α and a tamoxifen-inducible Cre recombinase (CreERT2) driven by a ubiquitous CAG promoter. After tamoxifen administration, tdTomato expression would be driven in cells that contain stabilized HIF-1α. Intraocular pressure (IOP) and visual evoked potential (VEP) were measured after OHT at 3, 14, and 28 days (d) to evaluate hypoxia induction. Immunolabeling of hypoxic cell types in the retina and optic nerve (ON) was performed, as well as retinal ganglion cell (RGC) and axon number quantification at each time point (6 h, 3 d, 14 d, 28 d). IOP elevation and VEP decrease were detected 3 d after OHT, which preceded RGC soma and axon loss at 14 and 28 d after OHT. Hypoxia was detected primarily in Müller glia in the retina, and microglia and astrocytes in the ON and optic nerve head (ONH). Hypoxia-induced factor (HIF-α) regulates the expression of glucose transporters 1 and 3 (GLUT1, 3) to support neuronal metabolic demand. Significant increases in GLUT1 and 3 proteins were observed in the retina and ON after OHT. Interestingly, neurons and endothelial cells within the superior colliculus in the brain also experienced hypoxia after OHT as determined by tdTomato expression. The highest intensity labeling for hypoxia was detected in the ONH. Initiation of OHT resulted in significant hypoxia that did not immediately resolve, with low-level hypoxia apparent out to 14 and 28 d, suggesting that continued hypoxia contributes to glaucoma progression. Restricted hypoxia in retinal neurons after OHT suggests a hypoxia management role for glia.
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11
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Jiang Y, Duan LJ, Fong GH. Oxygen-sensing mechanisms in development and tissue repair. Development 2021; 148:273632. [PMID: 34874450 DOI: 10.1242/dev.200030] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Under normoxia, hypoxia inducible factor (HIF) α subunits are hydroxylated by PHDs (prolyl hydroxylase domain proteins) and subsequently undergo polyubiquitylation and degradation. Normal embryogenesis occurs under hypoxia, which suppresses PHD activities and allows HIFα to stabilize and regulate development. In this Primer, we explain molecular mechanisms of the oxygen-sensing pathway, summarize HIF-regulated downstream events, discuss loss-of-function phenotypes primarily in mouse development, and highlight clinical relevance to angiogenesis and tissue repair.
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Affiliation(s)
- Yida Jiang
- Center for Vascular Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Li-Juan Duan
- Center for Vascular Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Guo-Hua Fong
- Center for Vascular Biology, University of Connecticut Health Center, Farmington, CT 06030, USA.,Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
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12
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Lee HW, Xu Y, He L, Choi W, Gonzalez D, Jin SW, Simons M. Role of Venous Endothelial Cells in Developmental and Pathologic Angiogenesis. Circulation 2021; 144:1308-1322. [PMID: 34474596 DOI: 10.1161/circulationaha.121.054071] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Angiogenesis is a dynamic process that involves expansion of a preexisting vascular network that can occur in a number of physiological and pathological settings. Despite its importance, the origin of the new angiogenic vasculature is poorly defined. In particular, the primary subtype of endothelial cells (capillary, venous, arterial) driving this process remains undefined. METHODS Endothelial cells were fate-mapped with the use of genetic markers specific to arterial and capillary cells. In addition, we identified a novel venous endothelial marker gene (Gm5127) and used it to generate inducible venous endothelium-specific Cre and Dre driver mouse lines. Contributions of these various types of endothelial cells to angiogenesis were examined during normal postnatal development and in disease-specific setting. RESULTS Using a comprehensive set of endothelial subtype-specific inducible reporter mice, including tip, arterial, and venous endothelial reporter lines, we showed that venous endothelial cells are the primary endothelial subtype responsible for the expansion of an angiogenic vascular network. During physiological angiogenesis, venous endothelial cells proliferate, migrating against the blood flow and differentiating into tip, capillary, and arterial endothelial cells of the new vasculature. Using intravital 2-photon imaging, we observed venous endothelial cells migrating against the blood flow to form new blood vessels. Venous endothelial cell migration also plays a key role in pathological angiogenesis. This was observed both in formation of arteriovenous malformations in mice with inducible endothelium-specific Smad4 deletion mice and in pathological vessel growth seen in oxygen-induced retinopathy. CONCLUSIONS Our studies establish that venous endothelial cells are the primary endothelial subtype responsible for normal expansion of vascular networks, formation of arteriovenous malformations, and pathological angiogenesis. These observations highlight the central role of the venous endothelium in normal development and disease pathogenesis.
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Affiliation(s)
- Heon-Woo Lee
- Yale Cardiovascular Research Center (H.-W.L., Y.X., S.-W.J., M.S.), Yale University School of Medicine, New Haven, CT
| | - Yanying Xu
- Yale Cardiovascular Research Center (H.-W.L., Y.X., S.-W.J., M.S.), Yale University School of Medicine, New Haven, CT.,Department of Cardiovascular Medicine, Xiangya Hospital, Central South University, Changsha, China (Y.X.)
| | - Liqun He
- Department of Immunology, Genetics, and Pathology, Rudbeck Laboratory, Uppsala University, Sweden (L.H.)
| | - Woosoung Choi
- School of Life Sciences and Cell Logistics Research Center, Gwangju Institute of Science and Technology, Korea (W.C., S.-W.J.)
| | - David Gonzalez
- Department of Genetics (D.G.), Yale University School of Medicine, New Haven, CT
| | - Suk-Won Jin
- Yale Cardiovascular Research Center (H.-W.L., Y.X., S.-W.J., M.S.), Yale University School of Medicine, New Haven, CT.,School of Life Sciences and Cell Logistics Research Center, Gwangju Institute of Science and Technology, Korea (W.C., S.-W.J.)
| | - Michael Simons
- Yale Cardiovascular Research Center (H.-W.L., Y.X., S.-W.J., M.S.), Yale University School of Medicine, New Haven, CT.,Department of Cell Biology (M.S.), Yale University School of Medicine, New Haven, CT
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13
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Implication of N-Methyl-d-Aspartate Receptor in Homocysteine-Induced Age-Related Macular Degeneration. Int J Mol Sci 2021; 22:ijms22179356. [PMID: 34502266 PMCID: PMC8431693 DOI: 10.3390/ijms22179356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/12/2021] [Accepted: 08/26/2021] [Indexed: 02/03/2023] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of vision loss. Elevated homocysteine (Hcy) (Hyperhomocysteinemia) (HHcy) has been reported in AMD. We previously reported that HHcy induces AMD-like features. This study suggests that N-Methyl-d-aspartate receptor (NMDAR) activation in the retinal pigment epithelium (RPE) is a mechanism for HHcy-induced AMD. Serum Hcy and cystathionine-β-synthase (CBS) were assessed by ELISA. The involvement of NMDAR in Hcy-induced AMD features was evaluated (1) in vitro using ARPE-19 cells, primary RPE isolated from HHcy mice (CBS), and mouse choroidal endothelial cells (MCEC); (2) in vivo using wild-type mice and mice deficient in RPE NMDAR (NMDARR−/−) with/without Hcy injection. Isolectin-B4, Ki67, HIF-1α, VEGF, NMDAR1, and albumin were assessed by immunofluorescence (IF), Western blot (WB), Optical coherence tomography (OCT), and fluorescein angiography (FA) to evaluate retinal structure, fluorescein leakage, and choroidal neovascularization (CNV). A neovascular AMD patient’s serum showed a significant increase in Hcy and a decrease in CBS. Hcy significantly increased HIF-1α, VEGF, and NMDAR in RPE cells, and Ki67 in MCEC. Hcy-injected WT mice showed disrupted retina and CNV. Knocking down RPE NMDAR improved retinal structure and CNV. Our findings underscore the role of RPE NMDAR in Hcy-induced AMD features; thus, NMDAR inhibition could serve as a promising therapeutic target for AMD.
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14
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Zhang J, Qin Y, Martinez M, Flores-Bellver M, Rodrigues M, Dinabandhu A, Cao X, Deshpande M, Qin Y, Aparicio-Domingo S, Rui Y, Tzeng SY, Salman S, Yuan J, Scott AW, Green JJ, Canto-Soler MV, Semenza GL, Montaner S, Sodhi A. HIF-1α and HIF-2α redundantly promote retinal neovascularization in patients with ischemic retinal disease. J Clin Invest 2021; 131:e139202. [PMID: 34128478 PMCID: PMC8203455 DOI: 10.1172/jci139202] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 05/05/2021] [Indexed: 01/14/2023] Open
Abstract
Therapies targeting VEGF have proven only modestly effective for the treatment of proliferative sickle cell retinopathy (PSR), the leading cause of blindness in patients with sickle cell disease. Here, we shift our attention upstream from the genes that promote retinal neovascularization (NV) to the transcription factors that regulate their expression. We demonstrated increased expression of HIF-1α and HIF-2α in the ischemic inner retina of PSR eyes. Although both HIFs participated in promoting VEGF expression by hypoxic retinal Müller cells, HIF-1 alone was sufficient to promote retinal NV in mice, suggesting that therapies targeting only HIF-2 would not be adequate to prevent PSR. Nonetheless, administration of a HIF-2-specific inhibitor currently in clinical trials (PT2385) inhibited NV in the oxygen-induced retinopathy (OIR) mouse model. To unravel these discordant observations, we examined the expression of HIFs in OIR mice and demonstrated rapid but transient accumulation of HIF-1α but delayed and sustained accumulation of HIF-2α; simultaneous expression of HIF-1α and HIF-2α was not observed. Staggered HIF expression was corroborated in hypoxic adult mouse retinal explants but not in human retinal organoids, suggesting that this phenomenon may be unique to mice. Using pharmacological inhibition or an in vivo nanoparticle-mediated RNAi approach, we demonstrated that inhibiting either HIF was effective for preventing NV in OIR mice. Collectively, these results explain why inhibition of either HIF-1α or HIF-2α is equally effective for preventing retinal NV in mice but suggest that therapies targeting both HIFs will be necessary to prevent NV in patients with PSR.
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Affiliation(s)
- Jing Zhang
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yaowu Qin
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Eye, Ear, Nose and Throat Hospital, Fudan University, Shanghai, China
| | - Mireya Martinez
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Miguel Flores-Bellver
- CellSight Ocular Stem Cell and Regeneration Research Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Murilo Rodrigues
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Aumreetam Dinabandhu
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Oncology and Diagnostic Sciences, School of Dentistry, Greenebaum Cancer Center, University of Maryland, Baltimore, Maryland, USA
| | - Xuan Cao
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Monika Deshpande
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Yu Qin
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Ophthalmology, Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Key Lens Research Laboratory of Liaoning Province, Shenyang, Liaoning, China
| | - Silvia Aparicio-Domingo
- CellSight Ocular Stem Cell and Regeneration Research Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Yuan Rui
- Department of Biomedical Engineering, Institute for NanoBioTechnology, and Translational Tissue Engineering Center, and
| | - Stephany Y. Tzeng
- Department of Biomedical Engineering, Institute for NanoBioTechnology, and Translational Tissue Engineering Center, and
| | - Shaima Salman
- Departments of Pediatrics, Medicine, Oncology, Radiation Oncology, Biological Chemistry, and Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jin Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Adrienne W. Scott
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jordan J. Green
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Biomedical Engineering, Institute for NanoBioTechnology, and Translational Tissue Engineering Center, and
| | - M. Valeria Canto-Soler
- CellSight Ocular Stem Cell and Regeneration Research Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Gregg L. Semenza
- Departments of Pediatrics, Medicine, Oncology, Radiation Oncology, Biological Chemistry, and Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Silvia Montaner
- Department of Oncology and Diagnostic Sciences, School of Dentistry, Greenebaum Cancer Center, University of Maryland, Baltimore, Maryland, USA
| | - Akrit Sodhi
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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15
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An allosteric peptide inhibitor of HIF-1α regulates hypoxia-induced retinal neovascularization. Proc Natl Acad Sci U S A 2020; 117:28297-28306. [PMID: 33106407 DOI: 10.1073/pnas.2017234117] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Retinal neovascularization (NV), a leading cause of vision loss, results from localized hypoxia that stabilizes the hypoxia-inducible transcription factors HIF-1α and HIF-2α, enabling the expression of angiogenic factors and genes required to maintain homeostasis under conditions of oxygen stress. HIF transcriptional activity depends on the interaction between its intrinsically disordered C-terminal domain and the transcriptional coactivators CBP/p300. Much effort is currently directed at disrupting protein-protein interactions between disease-associated transcription factors like HIF and their cellular partners. The intrinsically disordered protein CITED2, a direct product of HIF-mediated transcription, functions as a hypersensitive negative regulator that attenuates the hypoxic response by competing allosterically with HIF-1α for binding to CBP/p300. Here, we show that a peptide fragment of CITED2 is taken up by retinal cells and efficiently regulates pathological angiogenesis in murine models of ischemic retinopathy. Both vaso-obliteration (VO) and NV were significantly inhibited in an oxygen-induced retinopathy (OIR) model following intravitreal injection of the CITED2 peptide. The CITED2 peptide localized to retinal neurons and glia, resulting in decreased expression of HIF target genes. Aflibercept, a commonly used anti-VEGF therapy for retinal neovascular diseases, rescued NV but not VO in OIR. However, a combination of the CITED2 peptide and a reduced dose of aflibercept significantly decreased both NV and VO. In contrast to anti-VEGF agents, the CITED2 peptide can rescue hypoxia-induced retinal NV by modulating the hypoxic response through direct competition with HIF for CBP/p300, suggesting a dual targeting strategy for treatment of ischemic retinal diseases and other neovascular disorders.
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16
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Picard E, Daruich A, Youale J, Courtois Y, Behar-Cohen F. From Rust to Quantum Biology: The Role of Iron in Retina Physiopathology. Cells 2020; 9:cells9030705. [PMID: 32183063 PMCID: PMC7140613 DOI: 10.3390/cells9030705] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/07/2020] [Accepted: 03/09/2020] [Indexed: 12/24/2022] Open
Abstract
Iron is essential for cell survival and function. It is a transition metal, that could change its oxidation state from Fe2+ to Fe3+ involving an electron transfer, the key of vital functions but also organ dysfunctions. The goal of this review is to illustrate the primordial role of iron and local iron homeostasis in retinal physiology and vision, as well as the pathological consequences of iron excess in animal models of retinal degeneration and in human retinal diseases. We summarize evidence of the potential therapeutic effect of iron chelation in retinal diseases and especially the interest of transferrin, a ubiquitous endogenous iron-binding protein, having the ability to treat or delay degenerative retinal diseases.
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Affiliation(s)
- Emilie Picard
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, USPC, Université Paris Descartes, Team 17, F-75006 Paris, France; (A.D.); (J.Y.); (Y.C.); (F.B.-C.)
- Correspondence: ; Tel.: +331-44-27-81-82
| | - Alejandra Daruich
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, USPC, Université Paris Descartes, Team 17, F-75006 Paris, France; (A.D.); (J.Y.); (Y.C.); (F.B.-C.)
- Ophthalmology Department, Necker-Enfants Malades University Hospital, APHP, 75015 Paris, France
| | - Jenny Youale
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, USPC, Université Paris Descartes, Team 17, F-75006 Paris, France; (A.D.); (J.Y.); (Y.C.); (F.B.-C.)
| | - Yves Courtois
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, USPC, Université Paris Descartes, Team 17, F-75006 Paris, France; (A.D.); (J.Y.); (Y.C.); (F.B.-C.)
| | - Francine Behar-Cohen
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, USPC, Université Paris Descartes, Team 17, F-75006 Paris, France; (A.D.); (J.Y.); (Y.C.); (F.B.-C.)
- Ophtalmopole, Cochin Hospital, AP-HP, Assistance Publique Hôpitaux de Paris, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
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17
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Stabilization of myeloid-derived HIFs promotes vascular regeneration in retinal ischemia. Angiogenesis 2019; 23:83-90. [PMID: 31583505 PMCID: PMC7160070 DOI: 10.1007/s10456-019-09681-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 09/18/2019] [Indexed: 12/19/2022]
Abstract
The retinal vasculature is tightly organized in a structure that provides for the high metabolic demand of neurons while minimizing interference with incident light. The adverse impact of retinal vascular insufficiency is mitigated by adaptive vascular regeneration but exacerbated by pathological neovascularization. Aberrant growth of neovessels in the retina is responsible for impairment of sight in common blinding disorders including retinopathy of prematurity, proliferative diabetic retinopathy, and age-related macular degeneration. Myeloid cells are key players in this process, with diverse roles that can either promote or protect against ocular neovascularization. We have previously demonstrated that myeloid-derived VEGF, HIF1, and HIF2 are not essential for pathological retinal neovascularization. Here, however, we show by cell-specific depletion of Vhl in a mouse model of retinal ischemia (oxygen-induced retinopathy, OIR) that myeloid-derived HIFs promote VEGF and bFGF expression and enhance vascular regeneration in association with improved density and organization of the astrocytic network.
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18
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Rattner A, Williams J, Nathans J. Roles of HIFs and VEGF in angiogenesis in the retina and brain. J Clin Invest 2019; 129:3807-3820. [PMID: 31403471 DOI: 10.1172/jci126655] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 06/13/2019] [Indexed: 12/17/2022] Open
Abstract
Vascular development in the mammalian retina is a paradigm for CNS vascular development in general, and its study is revealing fundamental mechanisms that explain the efficacy of antiangiogenic therapies in retinal vascular disease. During development of the mammalian retina, hypoxic astrocytes are hypothesized to secrete VEGF, which attracts growing endothelial cells as they migrate radially from the optic disc. However, published tests of this model using astrocyte-specific deletion of Vegf in the developing mouse retina appear to contradict this theory. Here, we report that selectively eliminating Vegf in neonatal retinal astrocytes with a Gfap-Cre line that recombines with approximately 100% efficiency had no effect on proliferation or radial migration of astrocytes, but completely blocked radial migration of endothelial cells, strongly supporting the hypoxic astrocyte model. Using additional Cre driver lines, we found evidence for essential and partially redundant actions of retina-derived (paracrine) and astrocyte-derived (autocrine) VEGF in controlling astrocyte proliferation and migration. We also extended previous studies by showing that HIF-1α in retinal neurons and HIF-2α in Müller glia play distinct roles in retinal vascular development and disease, adding to a growing body of data that point to the specialization of these 2 hypoxia-sensing transcription factors.
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Affiliation(s)
| | - John Williams
- Department of Molecular Biology and Genetics.,Howard Hughes Medical Institute
| | - Jeremy Nathans
- Department of Molecular Biology and Genetics.,Howard Hughes Medical Institute.,Department of Neuroscience, and.,Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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19
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Jassim AH, Inman DM. Evidence of Hypoxic Glial Cells in a Model of Ocular Hypertension. Invest Ophthalmol Vis Sci 2019; 60:1-15. [PMID: 30601926 PMCID: PMC6322635 DOI: 10.1167/iovs.18-24977] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Purpose Reoxygenation after hypoxia can increase reactive oxygen species and upregulate autophagy. We determined, for the first time, the impact of elevated IOP on hypoxia induction, superoxide accumulation, and autophagy in a bead model of glaucoma. Method Ocular hypertension was achieved with magnetic bead injection into the anterior chamber. Before mice were killed, they were injected with pimonidazole for hypoxia detection and dihydroethidium (DHE) for superoxide detection. Total retinal ganglion cells (RGCs) and optic nerve (ON) axons were quantified, total glutathione (GSH) was measured, and retinal and ON protein and mRNA were analyzed for hypoxia (Hif-1α and Hif-2α), autophagy (LC3 and p62), and SOD2. Results With IOP elevation (P < 0.0001), the retina showed significantly (P < 0.001) decreased GSH compared with control, and a significant decrease (P < 0.01) in RGC density compared with control. Pimonidazole-positive Müller glia, microglia, astrocytes, and RGCs were present in the retinas after 4 weeks of ocular hypertension but absent in both the control and after only 2 weeks of ocular hypertension. The ON showed significant axon degeneration (P < 0.0001). The mean intensity of DHE in the ganglion cell layer and ON significantly increased (P < 0.0001). The ratio of LC3-II to LC3-I revealed a significant increase (P < 0.05) in autophagic activity in hypertensive retinas compared with control. Conclusions We report a novel observation of hypoxia and a significant decrease in GSH, likely contributing to superoxide accumulation, in the retinas of ocular hypertensive mice. The significant increase in the ratio of LC3-II to LC3-I suggests autophagy induction.
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Affiliation(s)
- Assraa H Jassim
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, Ohio, United States
| | - Denise M Inman
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, Ohio, United States
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20
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Li X, Liu J, Hoh J, Liu J. Müller cells in pathological retinal angiogenesis. Transl Res 2019; 207:96-106. [PMID: 30639368 DOI: 10.1016/j.trsl.2018.12.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 12/06/2018] [Accepted: 12/21/2018] [Indexed: 02/07/2023]
Abstract
Müller cells are the major glial cells spanning the entire layer of the retina and maintaining retinal structure. Under pathological conditions, Müller cells are involved in retinal angiogenesis, a process of growing new blood vessels from pre-existing capillaries. In response to hypoxia, high glucose, and inflammation conditions, multiple signaling pathways are activated in Müller cells, followed by the increased production of proangiogenic factors including vascular endothelial growth factor, basic fibroblast growth factor, matrix metalloproteinases, Netrin-4, and angiopoietin-like 4. Expression of antiangiogenic factors is also downregulated in Müller cells. Besides, proliferation and dedifferentiation of Müller cells facilitates retinal angiogenesis. In this review, we summarized molecular mechanisms of Müller cells-related retinal angiogenesis. The potential of Müller cells as a therapeutic target for retinal angiogenesis was also discussed.
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Affiliation(s)
- Xiaorui Li
- Medical Research Center, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, China; Taishan Medical College, Taian, China
| | - Jing Liu
- Medical Research Center, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, China
| | - Josephine Hoh
- Department of Epidemiology and Public Health, Department of Ophthalmology and Visual Science, Yale University, New Haven, Connecticut
| | - Ju Liu
- Medical Research Center, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, China.
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21
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Increased expression of hypoxia-inducible factor-1 alpha and its impact on transcriptional changes and prognosis in malignant tumours of the ocular adnexa. Eye (Lond) 2018; 32:1772-1782. [PMID: 30065361 DOI: 10.1038/s41433-018-0172-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 06/19/2018] [Accepted: 06/26/2018] [Indexed: 01/06/2023] Open
Abstract
PURPOSE To investigate the expression profile of the hypoxia-inducible transcription factor-1α (HIF-1α) and its downstream targets in malignancies of the ocular adnexa and to determine its relevance as a prognostic factor for clinical outcome. METHODS We included 49 subjects with malignant tumours (25 squamous cell carcinomas (SCC), 15 non-Hodgkin lymphomas, 9 melanomas) and 30 patients with benign tumours of the ocular adnexa (13 papillomas, 7 reactive lymphoid hyperplasias (RLHs) and 10 nevi) as controls. We quantified HIF-1α protein expression by immunohistochemistry and assessed the association between HIF-1α and clinical outcome via Kaplan-Meier analysis. Furthermore, we assessed the expression of HIF-1α downstream factors by transcriptional sequencing using the MACE (massive analysis of cDNA ends) technology. RESULTS SCCs revealed a strong HIF-1α expression in 61% of tumour cells in comparison with only 22% in papillomas (p < 0.0001). In contrast, malignant melanomas and lymphomas revealed a similar HIF-1α expression compared with nevi and RLHs. Transcriptional sequencing and Gene Ontology Cluster analysis demonstrated 37 hypoxia-associated factors, including HIF-1α, VEGF, SFRP1 and LOXL2 that are significantly increased in SCC and may contribute to tumour proliferation, angiogenesis, and metastasis. Association analysis between HIF-1α immunoreactivity and clinical outcome revealed a trend towards an unfavourable prognosis in malignant tumours with increased HIF-1α expression. CONCLUSIONS HIF-1α protein is increased in malignant tumours of the ocular adnexa, which is associated with an increase in multiple HIF-1α-downstream factors and a trend towards an unfavourable clinical outcome.
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22
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Cristante E, Liyanage SE, Sampson RD, Kalargyrou A, De Rossi G, Rizzi M, Hoke J, Ribeiro J, Maswood RN, Duran Y, Matsuki T, Aghaizu ND, Luhmann UF, Smith AJ, Ali RR, Bainbridge JWB. Late neuroprogenitors contribute to normal retinal vascular development in a Hif2a-dependent manner. Development 2018; 145:dev.157511. [PMID: 29615467 DOI: 10.1242/dev.157511] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 03/20/2018] [Indexed: 12/20/2022]
Abstract
In the adult central nervous system, endothelial and neuronal cells engage in tight cross-talk as key components of the so-called neurovascular unit. Impairment of this important relationship adversely affects tissue homeostasis, as observed in neurodegenerative conditions including Alzheimer's and Parkinson's disease. In development, the influence of neuroprogenitor cells on angiogenesis is poorly understood. Here, we show in mouse that these cells interact intimately with the growing retinal vascular network, and we identify a novel regulatory mechanism of vasculature development mediated by hypoxia-inducible factor 2a (Hif2a). By Cre-lox gene excision, we show that Hif2a in retinal neuroprogenitor cells upregulates the expression of the pro-angiogenic mediators vascular endothelial growth factor and erythropoietin, whereas it locally downregulates the angiogenesis inhibitor endostatin. Importantly, absence of Hif2a in retinal neuroprogenitor cells causes a marked reduction of proliferating endothelial cells at the angiogenic front. This results in delayed retinal vascular development, fewer major retinal vessels and reduced density of the peripheral deep retinal vascular plexus. Our findings demonstrate that retinal neuroprogenitor cells are a crucial component of the developing neurovascular unit.
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Affiliation(s)
- Enrico Cristante
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK .,NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, City Road, London EC1V 2PD, UK
| | - Sidath E Liyanage
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK.,NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, City Road, London EC1V 2PD, UK
| | - Robert D Sampson
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | | | - Giulia De Rossi
- Centre for Microvascular Research, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Matteo Rizzi
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK.,NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, City Road, London EC1V 2PD, UK
| | - Justin Hoke
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Joana Ribeiro
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Ryea N Maswood
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Yanai Duran
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Takaaki Matsuki
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Nozie D Aghaizu
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Ulrich F Luhmann
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK.,NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, City Road, London EC1V 2PD, UK
| | - Alexander J Smith
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Robin R Ali
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK.,NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, City Road, London EC1V 2PD, UK
| | - James W B Bainbridge
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK .,NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, City Road, London EC1V 2PD, UK
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23
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Broadgate S, Kiire C, Halford S, Chong V. Diabetic macular oedema: under-represented in the genetic analysis of diabetic retinopathy. Acta Ophthalmol 2018; 96 Suppl A111:1-51. [PMID: 29682912 DOI: 10.1111/aos.13678] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 11/21/2017] [Indexed: 12/15/2022]
Abstract
Diabetic retinopathy, a complication of both type 1 and type 2 diabetes, is a complex disease and is one of the leading causes of blindness in adults worldwide. It can be divided into distinct subclasses, one of which is diabetic macular oedema. Diabetic macular oedema can occur at any time in diabetic retinopathy and is the most common cause of vision loss in patients with type 2 diabetes. The purpose of this review is to summarize the large number of genetic association studies that have been performed in cohorts of patients with type 2 diabetes and published in English-language journals up to February 2017. Many of these studies have produced positive associations with gene polymorphisms and diabetic retinopathy. However, this review highlights that within this large body of work, studies specifically addressing a genetic association with diabetic macular oedema, although present, are vastly under-represented. We also highlight that many of the studies have small patient numbers and that meta-analyses often inappropriately combine patient data sets. We conclude that there will continue to be conflicting results and no meaningful findings will be achieved if the historical approach of combining all diabetic retinopathy disease states within patient cohorts continues in future studies. This review also identifies several genes that would be interesting to analyse in large, well-defined cohorts of patients with diabetic macular oedema in future candidate gene association studies.
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Affiliation(s)
- Suzanne Broadgate
- Nuffield Laboratory of Ophthalmology; Nuffield Department of Clinical Neurosciences; University of Oxford; Oxford UK
| | - Christine Kiire
- Nuffield Laboratory of Ophthalmology; Nuffield Department of Clinical Neurosciences; University of Oxford; Oxford UK
- Oxford Eye Hospital; John Radcliffe Hospital; Oxford University NHS Foundation Trust; Oxford UK
| | - Stephanie Halford
- Nuffield Laboratory of Ophthalmology; Nuffield Department of Clinical Neurosciences; University of Oxford; Oxford UK
| | - Victor Chong
- Nuffield Laboratory of Ophthalmology; Nuffield Department of Clinical Neurosciences; University of Oxford; Oxford UK
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Chidlow G, Wood JPM, Casson RJ. Investigations into Hypoxia and Oxidative Stress at the Optic Nerve Head in a Rat Model of Glaucoma. Front Neurosci 2017; 11:478. [PMID: 28883787 PMCID: PMC5573812 DOI: 10.3389/fnins.2017.00478] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 08/11/2017] [Indexed: 01/03/2023] Open
Abstract
The vascular hypothesis of glaucoma proposes that retinal ganglion cell axons traversing the optic nerve head (ONH) undergo oxygen and nutrient insufficiency as a result of compromised local blood flow, ultimately leading to their degeneration. To date, evidence for the hypothesis is largely circumstantial. Herein, we made use of an induced rat model of glaucoma that features reproducible and widespread axonal transport disruption at the ONH following chronic elevation of intraocular pressure. If vascular insufficiency plays a role in the observed axonal transport failure, there should exist a physical signature at this time point. Using a range of immunohistochemical and molecular tools, we looked for cellular events indicative of vascular insufficiency, including the presence of hypoxia, upregulation of hypoxia-inducible, or antioxidant-response genes, alterations to antioxidant enzymes, increased formation of superoxide, and the presence of oxidative stress. Our data show that ocular hypertension caused selective hypoxia within the laminar ONH in 11/13 eyes graded as either medium or high for axonal transport disruption. Hypoxia was always present in areas featuring injured axons, and, the greater the abundance of axonal transport disruption, the greater the likelihood of a larger hypoxic region. Nevertheless, hypoxic regions were typically focal and were not necessarily evident in sections taken deeper within the same ONH, while disrupted axonal transport was frequently encountered without any discernible hypoxia. Ocular hypertension caused upregulation of heme oxygenase-1—an hypoxia-inducible and redox-sensitive enzyme—in ONH astrocytes. The distribution and abundance of heme oxygenase-1 closely matched that of axonal transport disruption, and encompassed hypoxic regions and their immediate penumbra. Ocular hypertension also caused upregulations in the iron-regulating protein ceruloplasmin, the anaerobic glycolytic enzyme lactate dehydrogenase, and the transcription factors cFos and p-cJun. Moreover, ocular hypertension increased the generation of superoxide radicals in the retina and ONH, as well as upregulating the active subunit of the superoxide-generating enzyme NADPH oxidase, and invoking modest alterations to antioxidant-response enzymes. The results of this study provide further indirect support for the hypothesis that reduced blood flow to the ONH contributes to axonal injury in glaucoma.
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Affiliation(s)
- Glyn Chidlow
- Ophthalmic Research Laboratories, Discipline of Ophthalmology and Visual Sciences, University of AdelaideAdelaide, SA, Australia
| | - John P M Wood
- Ophthalmic Research Laboratories, Discipline of Ophthalmology and Visual Sciences, University of AdelaideAdelaide, SA, Australia
| | - Robert J Casson
- Ophthalmic Research Laboratories, Discipline of Ophthalmology and Visual Sciences, University of AdelaideAdelaide, SA, Australia
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25
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Gao ZJ, Wang Y, Yuan WD, Yuan JQ, Yuan K. HIF-2α not HIF-1α overexpression confers poor prognosis in non-small cell lung cancer. Tumour Biol 2017; 39:1010428317709637. [PMID: 28653893 DOI: 10.1177/1010428317709637] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
HIF-α may play an important role in the process of tumorigenesis as well as tumor progression. Although a number of investigations have established the significance of HIF-1α in several human tumors, there is still little information available on the clinical significance of HIF-2α expression in non-small cell lung cancer (NSCLC). In present study, immunohistologic expression of HIF-1α/ HIF-2α was studied in a tissue microarray of 140 Stage I-III NSCLCs and correlated with clinicopathologic parameters and clinical outcome. We found that HIF-1α/ HIF-2α showed a cytoplasmic pattern of expression in tumor cells while normal lung components showed negative or weak cytoplasmic staining. High HIF-1α and HIF-2α expression was noted in 49/140 (35.0%) and in 64/140 (45.7%) of the cases respectively. There was no direct correlation between HIF-1α and HIF-2α expression ( p = 0.200). The high HIF-2α expression was associated with histology (squamous cell carcinoma vs. adenocarcinomas) in these patients ( p = 0.001). Patients in advanced tumor stage had frequent high expression of HIF-2α ( p = 0.007), and the similar high expression was also observed in advanced T or N stage ( p = 0.030 and 0.043, respectively). HIF-1α showed a marginal association with T stage ( p = 0.084), which showed a higher expression in early tumor stage. Univariate analysis of the overall survival demonstrates that HIF-2α expression but not HIF-1α was related to poor outcome ( p = 0.005) and it retained significance in multivariate analysis ( p = 0.046). In conclusion, HIF-2α expression was related to tumor size, lymph node metastasis, tumor stage and histology. We also found a positive prognostic value of HIF-2α protein expression. HIF-2α might serve as a potential prognosis biomarker in evaluating progression and prognosis of NSCLC. We believe that our study will be of great benefit to the clinical treatment and prognostic evaluation of NSCLC.
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Affiliation(s)
- Zhao-Jia Gao
- 1 Division of Thoracic Surgery, Changzhou No. 2 People's Hospital, Nanjing Medical University, Changzhou, China.,2 Heart and Lung Disease Laboratory, Changzhou No. 2 People's Hospital, Nanjing Medical University, Changzhou, China
| | - Yong Wang
- 1 Division of Thoracic Surgery, Changzhou No. 2 People's Hospital, Nanjing Medical University, Changzhou, China
| | - Wei-Dong Yuan
- 1 Division of Thoracic Surgery, Changzhou No. 2 People's Hospital, Nanjing Medical University, Changzhou, China
| | - Jun-Qiang Yuan
- 1 Division of Thoracic Surgery, Changzhou No. 2 People's Hospital, Nanjing Medical University, Changzhou, China
| | - Kai Yuan
- 1 Division of Thoracic Surgery, Changzhou No. 2 People's Hospital, Nanjing Medical University, Changzhou, China.,2 Heart and Lung Disease Laboratory, Changzhou No. 2 People's Hospital, Nanjing Medical University, Changzhou, China
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26
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Evans CE, Palazon A, Sim J, Tyrakis PA, Prodger A, Lu X, Chan S, Bendahl PO, Belting M, Von Euler L, Rundqvist H, Johnson RS, Branco C. Modelling pulmonary microthrombosis coupled to metastasis: distinct effects of thrombogenesis on tumorigenesis. Biol Open 2017; 6:688-697. [PMID: 28302670 PMCID: PMC5450329 DOI: 10.1242/bio.024653] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Thrombosis can cause localized ischemia and tissue hypoxia, and both of these are linked to cancer metastasis. Vascular micro-occlusion can occur as a result of arrest of circulating tumour cells in small capillaries, giving rise to microthrombotic events that affect flow, creating localized hypoxic regions. To better understand the association between metastasis and thrombotic events, we generated an experimental strategy whereby we modelled the effect of microvascular occlusion in metastatic efficiency by using inert microbeads to obstruct lung microvasculature before, during and after intravenous tumour cell injection. We found that controlled induction of a specific number of these microthrombotic insults in the lungs caused an increase in expression of the hypoxia-inducible transcription factors (HIFs), a pro-angiogenic and pro-tumorigenic environment, as well as an increase in myeloid cell infiltration. Induction of pulmonary microthrombosis prior to introduction of tumour cells to the lungs had no effect on tumorigenic success, but thrombosis at the time of tumour cell seeding increased number and size of tumours in the lung, and this effect was strikingly more pronounced when the micro-occlusion occurred on the day following introduction of tumour cells. The tumorigenic effect of microbead treatment was seen even when thrombosis was induced five days after tumour cell injection. We also found positive correlations between thrombotic factors and expression of HIF2α in human tumours. The model system described here demonstrates the importance of thrombotic insult in metastatic success and can be used to improve understanding of thrombosis-associated tumorigenesis and its treatment. Summary: Induction of pulmonary microthrombosis by three distinct methods enhances HIF-a expression and tumour formation; increases in tumorigenesis that are induced by these thrombotic insults occur in a time- and mode-dependent manner.
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Affiliation(s)
- Colin E Evans
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK.,British Heart Foundation Centre of Research Excellence, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Asis Palazon
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Jingwei Sim
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Petros A Tyrakis
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Alice Prodger
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Xiao Lu
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Saria Chan
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Pär-Ola Bendahl
- Department of Clinical Sciences, Lund University, Lund, SE-221 00, Sweden
| | - Mattias Belting
- Department of Clinical Sciences, Lund University, Lund, SE-221 00, Sweden
| | - Love Von Euler
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Helene Rundqvist
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Randall S Johnson
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK .,Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Cristina Branco
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
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Kim YJ, Park SJ, Kim NR, Chin HS. Effects of Histone Deacetylase Inhibitor (Valproic Acid) on the Expression of Hypoxia-inducible Factor-1 Alpha in Human Retinal Müller Cells. KOREAN JOURNAL OF OPHTHALMOLOGY 2017; 31:80-85. [PMID: 28243027 PMCID: PMC5327178 DOI: 10.3341/kjo.2017.31.1.80] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 03/21/2016] [Indexed: 11/23/2022] Open
Abstract
Purpose To evaluate the effects of valproic acid (VPA), a histone deacetylase inhibitor (HDACI), on the expression of hypoxia-inducible factor-1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF) in human retinal Müller cells under hypoxic conditions. Methods Chemical hypoxia was induced in human retinal Müller cells (MIO-M1) by treatment with increasing concentrations of cobalt(II) chloride (CoCl2). Müller cells were also treated with a set concentration of CoCl2, along with various concentrations of VPA. The expression of HIF-1α and VEGF in the treated Müller cells was determined by enzyme-linked immunosorbent assay. Results Exposure of human retinal Müller cells to increasing concentrations of CoCl2 produced a dose-dependent increase in HIF-1α expression. The addition of increasing concentrations of VPA lead to a dose-dependent decrease in expression of HIF-1α and VEGF in Müller cells exposed to a set concentration of CoCl2. Conclusions HDACI VPA downregulated the expressions of HIF-1α and VEGF in human retinal Müller cells under hypoxic conditions. Using HDACI to target HIF-1α expression in Müller cells could be a new therapeutic strategy for the treatment of retinal vascular diseases.
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Affiliation(s)
- Young Jun Kim
- Department of Ophthalmology and Inha Vision Science Laboratory, Inha University School of Medicine, Incheon, Korea
| | - Sang Jun Park
- Department of Ophthalmology and Inha Vision Science Laboratory, Inha University School of Medicine, Incheon, Korea
| | - Na Rae Kim
- Department of Ophthalmology and Inha Vision Science Laboratory, Inha University School of Medicine, Incheon, Korea
| | - Hee Seung Chin
- Department of Ophthalmology and Inha Vision Science Laboratory, Inha University School of Medicine, Incheon, Korea
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Mammadzada P, Gudmundsson J, Kvanta A, André H. Differential hypoxic response of human choroidal and retinal endothelial cells proposes tissue heterogeneity of ocular angiogenesis. Acta Ophthalmol 2016; 94:805-814. [PMID: 27255568 DOI: 10.1111/aos.13119] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 04/14/2016] [Indexed: 02/06/2023]
Abstract
PURPOSE To elaborate molecular differences between choroidal and retinal angiogenesis by generating and comparatively analysing human primary choroidal and retinal endothelial cell (CEC and REC) lines. METHODS Human CEC and REC were isolated by positive selection and were cultured. Characterization was performed by immunostaining for endothelial cell (EC)-specific markers. Total RNA and protein were extracted from normoxic or hypoxic CEC and REC cultures. Quantitative polymerase chain reaction (PCR) arrays were used to comparatively analyse 133 genes between CEC and REC, and the expression differences were calculated by ΔΔCt method. A total of 57 angiogenesis-related protein expression differences were investigated by Western blot and proteome profiler and were calculated by densitometry. RESULTS Primary human CEC and REC lines stained positively for all EC markers and demonstrated high purity with similar staining and morphology. Under normoxia, CEC showed significantly lower expression levels for cell proliferation and vessel maturation genes and higher expression levels for inflammation-related genes when compared to REC. In response to hypoxia, CEC and REC displayed differential regulation for a multitude of angiogenesis-related genes and proteins. Furthermore, within the vascular endothelial growth factor (VEGF) family, CEC showed preferential upregulation for vascular endothelial growth factor A (VEGFA) while REC upregulated placenta growth factor (PlGF) levels. CONCLUSION Differential normoxic and hypoxic regulation of angiogenesis-related factors by CEC and REC outlines tissue heterogeneity of ocular angiogenesis and suggests that tissue specificity should be considered as a novel treatment modality for successfully overcoming choroidal and retinal angiogenic conditions in the clinic.
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Affiliation(s)
- Parviz Mammadzada
- Section of Ophthalmology and Vision; Department of Clinical Neuroscience; St. Erik Eye Hospital; Karolinska Institute; Stockholm Sweden
| | - Johann Gudmundsson
- Section of Ophthalmology and Vision; Department of Clinical Neuroscience; St. Erik Eye Hospital; Karolinska Institute; Stockholm Sweden
| | - Anders Kvanta
- Section of Ophthalmology and Vision; Department of Clinical Neuroscience; St. Erik Eye Hospital; Karolinska Institute; Stockholm Sweden
| | - Helder André
- Section of Ophthalmology and Vision; Department of Clinical Neuroscience; St. Erik Eye Hospital; Karolinska Institute; Stockholm Sweden
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29
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Larrayoz IM, Rey-Funes M, Contartese DS, Rolón F, Sarotto A, Dorfman VB, Loidl CF, Martínez A. Cold Shock Proteins Are Expressed in the Retina Following Exposure to Low Temperatures. PLoS One 2016; 11:e0161458. [PMID: 27556928 PMCID: PMC4996528 DOI: 10.1371/journal.pone.0161458] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 08/05/2016] [Indexed: 12/05/2022] Open
Abstract
Hypothermia has been proposed as a therapeutic intervention for some retinal conditions, including ischemic insults. Cold exposure elevates expression of cold-shock proteins (CSP), including RNA-binding motif protein 3 (RBM3) and cold inducible RNA-binding protein (CIRP), but their presence in mammalian retina is so far unknown. Here we show the effects of hypothermia on the expression of these CSPs in retina-derived cell lines and in the retina of newborn and adult rats. Two cell lines of retinal origin, R28 and mRPE, were exposed to 32°C for different time periods and CSP expression was measured by qRT-PCR and Western blotting. Neonatal and adult Sprague-Dawley rats were exposed to a cold environment (8°C) and expression of CSPs in their retinas was studied by Western blotting, multiple inmunofluorescence, and confocal microscopy. RBM3 expression was upregulated by cold in both R28 and mRPE cells in a time-dependent fashion. On the other hand, CIRP was upregulated in R28 cells but not in mRPE. In vivo, expression of CSPs was negligible in the retina of newborn and adult rats kept at room temperature (24°C). Exposure to a cold environment elicited a strong expression of both proteins, especially in retinal pigment epithelium cells, photoreceptors, bipolar, amacrine and horizontal cells, Müller cells, and ganglion cells. In conclusion, CSP expression rapidly rises in the mammalian retina following exposure to hypothermia in a cell type-specific pattern. This observation may be at the basis of the molecular mechanism by which hypothermia exerts its therapeutic effects in the retina.
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Affiliation(s)
- Ignacio M. Larrayoz
- Angiogenesis Study Group, Center for Biomedical Research of La Rioja (CIBIR), 26006, Logroño, Spain
- * E-mail:
| | - Manuel Rey-Funes
- Laboratorio de Neuropatología Experimental, Instituto de Biología Celular y Neurociencia “Prof. E. De Robertis” (IBCN), Facultad de Medicina, Universidad de Buenos Aires, CONICET, Paraguay 2155 (C1428ABG), Ciudad Autónoma de Buenos Aires, Argentina
| | - Daniela S. Contartese
- Laboratorio de Neuropatología Experimental, Instituto de Biología Celular y Neurociencia “Prof. E. De Robertis” (IBCN), Facultad de Medicina, Universidad de Buenos Aires, CONICET, Paraguay 2155 (C1428ABG), Ciudad Autónoma de Buenos Aires, Argentina
| | - Federico Rolón
- Laboratorio de Neuropatología Experimental, Instituto de Biología Celular y Neurociencia “Prof. E. De Robertis” (IBCN), Facultad de Medicina, Universidad de Buenos Aires, CONICET, Paraguay 2155 (C1428ABG), Ciudad Autónoma de Buenos Aires, Argentina
| | - Anibal Sarotto
- Laboratorio de Neuropatología Experimental, Instituto de Biología Celular y Neurociencia “Prof. E. De Robertis” (IBCN), Facultad de Medicina, Universidad de Buenos Aires, CONICET, Paraguay 2155 (C1428ABG), Ciudad Autónoma de Buenos Aires, Argentina
| | - Veronica B. Dorfman
- Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, Hidalgo 775 (C1405BCK), Ciudad Autónoma de Buenos Aires, Argentina
| | - Cesar F. Loidl
- Laboratorio de Neuropatología Experimental, Instituto de Biología Celular y Neurociencia “Prof. E. De Robertis” (IBCN), Facultad de Medicina, Universidad de Buenos Aires, CONICET, Paraguay 2155 (C1428ABG), Ciudad Autónoma de Buenos Aires, Argentina
- Laboratorio de Neurociencia, Facultad de Ciencias Médicas, Universidad Católica de Cuyo. San Juan, Argentina
| | - Alfredo Martínez
- Angiogenesis Study Group, Center for Biomedical Research of La Rioja (CIBIR), 26006, Logroño, Spain
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30
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Uddin MI, Evans SM, Craft JR, Capozzi ME, McCollum GW, Yang R, Marnett LJ, Uddin MJ, Jayagopal A, Penn JS. In Vivo Imaging of Retinal Hypoxia in a Model of Oxygen-Induced Retinopathy. Sci Rep 2016; 6:31011. [PMID: 27491345 PMCID: PMC4974503 DOI: 10.1038/srep31011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 07/11/2016] [Indexed: 01/16/2023] Open
Abstract
Ischemia-induced hypoxia elicits retinal neovascularization and is a major component of several blinding retinopathies such as retinopathy of prematurity (ROP), diabetic retinopathy (DR) and retinal vein occlusion (RVO). Currently, noninvasive imaging techniques capable of detecting and monitoring retinal hypoxia in living systems do not exist. Such techniques would greatly clarify the role of hypoxia in experimental and human retinal neovascular pathogenesis. In this study, we developed and characterized HYPOX-4, a fluorescence-imaging probe capable of detecting retinal-hypoxia in living animals. HYPOX-4 dependent in vivo and ex vivo imaging of hypoxia was tested in a mouse model of oxygen-induced retinopathy (OIR). Predicted patterns of retinal hypoxia were imaged by HYPOX-4 dependent fluorescence activity in this animal model. In retinal cells and mouse retinal tissue, pimonidazole-adduct immunostaining confirmed the hypoxia selectivity of HYPOX-4. HYPOX-4 had no effect on retinal cell proliferation as indicated by BrdU assay and exhibited no acute toxicity in retinal tissue as indicated by TUNEL assay and electroretinography (ERG) analysis. Therefore, HYPOX-4 could potentially serve as the basis for in vivo fluorescence-based hypoxia-imaging techniques, providing a tool for investigators to understand the pathogenesis of ischemic retinopathies and for physicians to address unmet clinical needs.
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Affiliation(s)
- Md. Imam Uddin
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Stephanie M. Evans
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jason R. Craft
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Megan E. Capozzi
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Gary W. McCollum
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Rong Yang
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Lawrence J. Marnett
- A. B. Hancock, Jr., Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry and Pharmacology, Vanderbilt Institute of Chemical Biology, Center for Molecular Toxicology and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Md. Jashim Uddin
- A. B. Hancock, Jr., Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry and Pharmacology, Vanderbilt Institute of Chemical Biology, Center for Molecular Toxicology and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Ashwath Jayagopal
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Ltd., Basel, Switzerland
| | - John S. Penn
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
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Lange C, Mowat F, Sayed H, Mehad M, Duluc L, Piper S, Luhmann U, Nandi M, Kelly P, Smith A, Ali R, Leiper J, Bainbridge J. Dimethylarginine dimethylaminohydrolase-2 deficiency promotes vascular regeneration and attenuates pathological angiogenesis. Exp Eye Res 2016; 147:148-155. [PMID: 27181226 PMCID: PMC4912010 DOI: 10.1016/j.exer.2016.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 05/04/2016] [Accepted: 05/09/2016] [Indexed: 11/21/2022]
Abstract
Ischemia-induced angiogenesis is critical for tissue repair, but aberrant neovascularization in the retina causes severe sight impairment. Nitric oxide (NO) has been implicated in neovascular eye disease because of its pro-angiogenic properties in the retina. Nitric oxide production is inhibited endogenously by asymmetric dimethylarginines (ADMA and L-NMMA) which are metabolized by dimethylarginine dimethylaminohydrolase (DDAH) 1 and 2. The aim of this study was to determine the roles of DDAH1, DDAH2, ADMA and L-NMMA in retinal ischemia-induced angiogenesis. First, DDAH1, DDAH2, ADMA and L-NMMA levels were determined in adult C57BL/6J mice. The results obtained revealed that DDAH1 was twofold increased in the retina compared to the brain and the choroid. DDAH2 expression was approximately 150 fold greater in retinal and 70 fold greater in choroidal tissue compared to brain tissue suggesting an important tissue-specific role for DDAH2 in the retina and choroid. ADMA and L-NMMA levels were similar in the retina and choroid under physiological conditions. Next, characterization of DDAH1+/− and DDAH2−/− deficient mice by in vivo fluorescein angiography, immunohistochemistry and electroretinography revealed normal neurovascular function compared with wildtype control mice. Finally, DDAH1+/− and DDAH2−/− deficient mice were studied in the oxygen-induced retinopathy (OIR) model, a model used to emulate retinal ischemia and neovascularization, and VEGF and ADMA levels were quantified by ELISA and liquid chromatography tandem mass spectrometry. In the OIR model, DDAH1+/− exhibited a similar phenotype compared to wildtype controls. DDAH2 deficiency, in contrast, resulted in elevated retinal ADMA which was associated with attenuated aberrant angiogenesis and improved vascular regeneration in a VEGF independent manner. Taken together this study suggests, that in retinal ischemia, DDAH2 deficiency elevates ADMA, promotes vascular regeneration and protects against aberrant angiogenesis. Therapeutic inhibition of DDAH2 may therefore offer a potential therapeutic strategy to protect sight by promoting retinal vascular regeneration and preventing pathological angiogenesis. Nitric oxide has been implicated in neovascular eye disease. Key inhibitor of NO production is ADMA, which is metabolized by DDAH. DDAH2 deficiency results in elevated ADMA and reduced neovascularization in mice. Therapeutic inhibition of ADMA or DDAH2 may offer a potential therapeutic strategy.
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Affiliation(s)
- Clemens Lange
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK; Eye Center, University Hospital Freiburg, Germany
| | - Freya Mowat
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | - Haroon Sayed
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | - Manjit Mehad
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | - Lucie Duluc
- The Nitric Oxide Signalling Group, MRC Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London, UK
| | - Sophie Piper
- The Nitric Oxide Signalling Group, MRC Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London, UK
| | - Ulrich Luhmann
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | - Manasi Nandi
- Institute of Pharmaceutical Science, King's College London, UK
| | - Peter Kelly
- The Nitric Oxide Signalling Group, MRC Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London, UK
| | - Alexander Smith
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | - Robin Ali
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | - James Leiper
- The Nitric Oxide Signalling Group, MRC Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London, UK
| | - James Bainbridge
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK.
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Kast B, Schori C, Grimm C. Hypoxic preconditioning protects photoreceptors against light damage independently of hypoxia inducible transcription factors in rods. Exp Eye Res 2016; 146:60-71. [DOI: 10.1016/j.exer.2015.12.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 12/15/2015] [Accepted: 12/17/2015] [Indexed: 12/17/2022]
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33
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Roy S, Amin S, Roy S. Retinal fibrosis in diabetic retinopathy. Exp Eye Res 2016; 142:71-5. [PMID: 26675403 DOI: 10.1016/j.exer.2015.04.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 03/20/2015] [Accepted: 04/08/2015] [Indexed: 01/10/2023]
Abstract
In response to injury, reparative processes are triggered to restore the damaged tissue; however, such processes are not always successful in rebuilding the original state. The formation of fibrous connective tissue is known as fibrosis, a hallmark of the reparative process. For fibrosis to be successful, delicately balanced cellular events involving cell proliferation, cell migration, and extracellular matrix (ECM) remodeling must occur in a highly orchestrated manner. While successful repair may result in a fibrous scar, this often restores structural stability and functionality to the injured tissue. However, depending on the functionality of the injured tissue, a fibrotic scar can have a devastating effect. For example, in the retina, fibrotic scarring may compromise vision and ultimately lead to blindness. In this review, we discuss some of the retinal fibrotic complications and highlight mechanisms underlying the development of retinal fibrosis in diabetic retinopathy.
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Affiliation(s)
- Sayon Roy
- Departments of Medicine and Ophthalmology, Boston University School of Medicine, Boston, MA, United States.
| | - Shruti Amin
- Departments of Medicine and Ophthalmology, Boston University School of Medicine, Boston, MA, United States
| | - Sumon Roy
- Departments of Medicine and Ophthalmology, Boston University School of Medicine, Boston, MA, United States
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Liyanage SE, Fantin A, Villacampa P, Lange CA, Denti L, Cristante E, Smith AJ, Ali RR, Luhmann UF, Bainbridge JW, Ruhrberg C. Myeloid-Derived Vascular Endothelial Growth Factor and Hypoxia-Inducible Factor Are Dispensable for Ocular Neovascularization--Brief Report. Arterioscler Thromb Vasc Biol 2015; 36:19-24. [PMID: 26603154 PMCID: PMC4684248 DOI: 10.1161/atvbaha.115.306681] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/12/2015] [Indexed: 11/16/2022]
Abstract
Supplemental Digital Content is available in the text. Ocular neovascularization (ONV) is a pathological feature of sight-threatening human diseases, such as diabetic retinopathy and age-related macular degeneration. Macrophage depletion in mouse models of ONV reduces the formation of pathological blood vessels, and myeloid cells are widely considered an important source of the vascular endothelial growth factor A (VEGF). However, the importance of VEGF or its upstream regulators hypoxia-inducible factor-1α (HIF1α) and hypoxia-inducible factor-2α (HIF2α) as myeloid-derived regulators of ONV remains to be determined.
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Affiliation(s)
- Sidath E Liyanage
- From the Divisions of Genetics (S.E.L., P.V., C.A.L., E.C., A.J.S., R.R.A., U.F.L., J.W.B.) and Cell Biology (A.F., L.D., C.R.), UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Alessandro Fantin
- From the Divisions of Genetics (S.E.L., P.V., C.A.L., E.C., A.J.S., R.R.A., U.F.L., J.W.B.) and Cell Biology (A.F., L.D., C.R.), UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Pilar Villacampa
- From the Divisions of Genetics (S.E.L., P.V., C.A.L., E.C., A.J.S., R.R.A., U.F.L., J.W.B.) and Cell Biology (A.F., L.D., C.R.), UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Clemens A Lange
- From the Divisions of Genetics (S.E.L., P.V., C.A.L., E.C., A.J.S., R.R.A., U.F.L., J.W.B.) and Cell Biology (A.F., L.D., C.R.), UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Laura Denti
- From the Divisions of Genetics (S.E.L., P.V., C.A.L., E.C., A.J.S., R.R.A., U.F.L., J.W.B.) and Cell Biology (A.F., L.D., C.R.), UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Enrico Cristante
- From the Divisions of Genetics (S.E.L., P.V., C.A.L., E.C., A.J.S., R.R.A., U.F.L., J.W.B.) and Cell Biology (A.F., L.D., C.R.), UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Alexander J Smith
- From the Divisions of Genetics (S.E.L., P.V., C.A.L., E.C., A.J.S., R.R.A., U.F.L., J.W.B.) and Cell Biology (A.F., L.D., C.R.), UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Robin R Ali
- From the Divisions of Genetics (S.E.L., P.V., C.A.L., E.C., A.J.S., R.R.A., U.F.L., J.W.B.) and Cell Biology (A.F., L.D., C.R.), UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Ulrich F Luhmann
- From the Divisions of Genetics (S.E.L., P.V., C.A.L., E.C., A.J.S., R.R.A., U.F.L., J.W.B.) and Cell Biology (A.F., L.D., C.R.), UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - James W Bainbridge
- From the Divisions of Genetics (S.E.L., P.V., C.A.L., E.C., A.J.S., R.R.A., U.F.L., J.W.B.) and Cell Biology (A.F., L.D., C.R.), UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Christiana Ruhrberg
- From the Divisions of Genetics (S.E.L., P.V., C.A.L., E.C., A.J.S., R.R.A., U.F.L., J.W.B.) and Cell Biology (A.F., L.D., C.R.), UCL Institute of Ophthalmology, University College London, London, United Kingdom.
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Pichu S, Sathiyamoorthy J, Krishnamoorthy E, Umapathy D, Viswanathan V. Impact of the hypoxia inducible factor-1α (HIF-1α) pro582ser polymorphism and its gene expression on diabetic foot ulcers. Diabetes Res Clin Pract 2015; 109:533-40. [PMID: 26113285 DOI: 10.1016/j.diabres.2015.05.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 04/08/2015] [Accepted: 05/03/2015] [Indexed: 12/18/2022]
Abstract
AIM Adaptation to low oxygen tension (hypoxia) in cells and tissues leads to the transcriptional induction of series of genes and the primary factor mediating this response is the hypoxia-inducible factor-1α. This study was designed in order to examine the HIF-1α gene polymorphism, p582s (rs11549465) in Exon-12 of HIF-1α gene in diabetic subjects with and without foot ulcers (DFU) and to find its expression under these pathological conditions. METHODS A total of 224 subjects from our tertiary care centre were included, which consists of healthy controls (N=66), type 2 diabetes mellitus (T2DM) (N=79) and T2DM with foot ulcers (DFU) (N=79). Allelic and genotypic comparisons between the different groups were evaluated by PCR-RFLP. The gene expression studies on selected samples (N=15 of each group) were done by Semi-quantitative real time PCR. RESULTS AND DISCUSSIONS Genotype analysis showed a significant increase in presence of 'T' allele in T2DM & DFU when compared to that of control subjects. Allele wise analysis showed a higher frequency of 'T' allele in the T2DM (62.03%) when compared to that of control subjects (53.79%). Interestingly, semi-quantitative RT-PCR results showed decreased expression of HIF-1α gene on DFU when compared to that of T2DM and control subjects. CONCLUSION Our findings predict that there is an association of HIF-1α gene polymorphism on foot ulcer patients when compare to that of healthy controls. Semi-quantitative real time studies showed decreased HIF-1α gene expression on foot ulcer patients suggesting its possible role on the pathogenesis.
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Affiliation(s)
- Sivakamasundari Pichu
- Prof. M. Viswanathan Diabetes Research Centre, MV Hospital for Diabetes, Royapuram, Chennai 600013, Tamil Nadu, India.
| | - Jayalalitha Sathiyamoorthy
- Prof. M. Viswanathan Diabetes Research Centre, MV Hospital for Diabetes, Royapuram, Chennai 600013, Tamil Nadu, India
| | - Ezhilarasi Krishnamoorthy
- Prof. M. Viswanathan Diabetes Research Centre, MV Hospital for Diabetes, Royapuram, Chennai 600013, Tamil Nadu, India
| | - Dhamodharan Umapathy
- Prof. M. Viswanathan Diabetes Research Centre, MV Hospital for Diabetes, Royapuram, Chennai 600013, Tamil Nadu, India
| | - Vijay Viswanathan
- Prof. M. Viswanathan Diabetes Research Centre, MV Hospital for Diabetes, Royapuram, Chennai 600013, Tamil Nadu, India.
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Nezgoda JT, Tsai FF, Nudleman E. Tractional Retinal Detachments in Adults and Children. CURRENT SURGERY REPORTS 2015. [DOI: 10.1007/s40137-015-0100-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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PEDF and its roles in physiological and pathological conditions: implication in diabetic and hypoxia-induced angiogenic diseases. Clin Sci (Lond) 2015; 128:805-23. [PMID: 25881671 PMCID: PMC4557399 DOI: 10.1042/cs20130463] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Pigment epithelium-derived factor (PEDF) is a broadly expressed multifunctional member of the serine proteinase inhibitor (serpin) family. This widely studied protein plays critical roles in many physiological and pathophysiological processes, including neuroprotection, angiogenesis, fibrogenesis and inflammation. The present review summarizes the temporal and spatial distribution patterns of PEDF in a variety of developing and adult organs, and discusses its functions in maintaining physiological homoeostasis. The major focus of the present review is to discuss the implication of PEDF in diabetic and hypoxia-induced angiogenesis, and the pathways mediating PEDF's effects under these conditions. Furthermore, the regulatory mechanisms of PEDF expression, function and degradation are also reviewed. Finally, the therapeutic potential of PEDF as an anti-angiogenic drug is briefly summarized.
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Lin WJ, Kuang HY. Oxidative stress induces autophagy in response to multiple noxious stimuli in retinal ganglion cells. Autophagy 2015; 10:1692-701. [PMID: 25207555 PMCID: PMC4198355 DOI: 10.4161/auto.36076] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Retinal ganglion cells (RGCs) are the only afferent neurons that can transmit visual information to the brain. The death of RGCs occurs in the early stages of glaucoma, diabetic retinopathy, and many other retinal diseases. Autophagy is a highly conserved lysosomal pathway, which is crucial for maintaining cellular homeostasis and cell survival under stressful conditions. Research has established that autophagy exists in RGCs after increasing intraocular pressure (IOP), retinal ischemia, optic nerve transection (ONT), axotomy, or optic nerve crush. However, the mechanism responsible for defining how autophagy is induced in RGCs has not been elucidated. Accumulating data has pointed to an essential role of reactive oxygen species (ROS) in the activation of autophagy. RGCs have long axons with comparatively high densities of mitochondria. This makes them more sensitive to energy deficiency and vulnerable to oxidative stress. In this review, we explore the role of oxidative stress in the activation of autophagy in RGCs, and discuss the possible mechanisms that are involved in this process. We aim to provide a more theoretical basis of oxidative stress-induced autophagy, and provide innovative targets for therapeutic intervention in retinopathy.
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Brodarac A, Šarić T, Oberwallner B, Mahmoodzadeh S, Neef K, Albrecht J, Burkert K, Oliverio M, Nguemo F, Choi YH, Neiss WF, Morano I, Hescheler J, Stamm C. Susceptibility of murine induced pluripotent stem cell-derived cardiomyocytes to hypoxia and nutrient deprivation. Stem Cell Res Ther 2015; 6:83. [PMID: 25900017 PMCID: PMC4445302 DOI: 10.1186/s13287-015-0057-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 05/23/2014] [Accepted: 03/19/2015] [Indexed: 01/06/2023] Open
Abstract
Introduction Induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs) may be suitable for myocardial repair. While their functional and structural properties have been extensively investigated, their response to ischemia-like conditions has not yet been clearly defined. Methods iPS-CMs were differentiated and enriched from murine induced pluripotent stem cells expressing enhanced green fluorescent protein (eGFP) and puromycin resistance genes under the control of an α-myosin heavy chain (α-MHC) promoter. iPS-CMs maturity and function were characterized by microscopy, real-time PCR, calcium transient recordings, electrophysiology, and mitochondrial function assays, and compared to those from neonatal murine cardiomyocytes. iPS-CMs as well as neonatal murine cardiomyocytes were exposed for 3 hours to hypoxia (1% O2) and glucose/serum deprivation, and viability, apoptosis markers, reactive oxygen species, mitochondrial membrane potential and intracellular stress signaling cascades were investigated. Then, the iPS-CMs response to mesenchymal stromal cell-conditioned medium was determined. Results iPS-CMs displayed key morphological and functional properties that were comparable to those of neonatal cardiomyocytes, but several parameters indicated an earlier iPS-CMs maturation stage. During hypoxia and glucose/serum deprivation, iPS-CMs exhibited a significantly higher proportion of poly-caspase-active, 7-aminoactinomycin D-positive and TUNEL-positive cells than neonatal cardiomyocytes. The average mitochondrial membrane potential was reduced in “ischemic” iPS-CMs but remained unchanged in neonatal cardiomyocytes; reactive oxygen species production was only increased in “ischemic” iPS-CMs, and oxidoreductase activity in iPS-CMs dropped more rapidly than in neonatal cardiomyocytes. In iPS-CMs, hypoxia and glucose/serum deprivation led to upregulation of Hsp70 transcripts and decreased STAT3 phosphorylation and total PKCε protein expression. Treatment with mesenchymal stromal cell-conditioned medium preserved oxidoreductase activity and restored pSTAT3 and PKCε levels. Conclusion iPS-CMs appear to be particularly sensitive to hypoxia and nutrient deprivation. Counteracting the ischemic susceptibility of iPS-CMs with mesenchymal stromal cell-conditioned medium may help enhance their survival and efficacy in cell-based approaches for myocardial repair.
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Affiliation(s)
- Andreja Brodarac
- Berlin-Brandenburg Center for Regenerative Therapies, Föhrer Str.15, Berlin, 13353, Germany.
| | - Tomo Šarić
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, Germany.
| | - Barbara Oberwallner
- Berlin-Brandenburg Center for Regenerative Therapies, Föhrer Str.15, Berlin, 13353, Germany.
| | | | - Klaus Neef
- Department of Cardiothoracic Surgery, Heart Center, University Hospital Cologne, Cologne, Germany.
| | - Julie Albrecht
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, Germany.
| | - Karsten Burkert
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, Germany.
| | - Matteo Oliverio
- Max-Planck-Institute for Metabolism Research, Cologne, Germany.
| | - Filomain Nguemo
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, Germany.
| | - Yeong-Hoon Choi
- Department of Cardiothoracic Surgery, Heart Center, University Hospital Cologne, Cologne, Germany.
| | - Wolfram F Neiss
- Department of Anatomy I, Medical Faculty, University of Cologne, Cologne, Germany.
| | - Ingo Morano
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.
| | - Jürgen Hescheler
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, Germany.
| | - Christof Stamm
- Berlin-Brandenburg Center for Regenerative Therapies, Föhrer Str.15, Berlin, 13353, Germany. .,Deutsches Herzzentrum Berlin, Berlin, Germany.
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Uddin MI, Evans SM, Craft JR, Marnett LJ, Uddin MJ, Jayagopal A. Applications of azo-based probes for imaging retinal hypoxia. ACS Med Chem Lett 2015; 6:445-9. [PMID: 25893047 DOI: 10.1021/ml5005206] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/12/2015] [Indexed: 11/29/2022] Open
Abstract
We report the design and synthesis of an activatable molecular imaging probe to detect hypoxia in mouse models of retinal vascular diseases. Hypoxia of the retina has been associated with the initiation and progression of blinding retinal vascular diseases including age-related macular degeneration, diabetic retinopathy, and retinopathy of prematurity. In vivo retinal imaging of hypoxia may be useful for early detection and timely treatment of retinal diseases. To achieve this goal, we synthesized HYPOX-3, a near-infrared (NIR) imaging agent coupled to a dark quencher, Black Hole Quencher 3 (BHQ3), which has been previously reported to contain a hypoxia-sensitive cleavable azo-bond. HYPOX-3 was cleaved in hypoxic retinal cell culture and animal models, enabling detection of hypoxia with high signal-to-noise ratios without acute toxicity. HYPOX-3 fluorescences in hypoxic cells and tissues and was undetectable under normoxia. These imaging agents are promising candidates for imaging retinal hypoxia in preclinical disease models and patients.
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Affiliation(s)
- Md. Imam Uddin
- Department
of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Stephanie M. Evans
- Department
of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Jason R. Craft
- Department
of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Lawrence J. Marnett
- A. B.
Hancock, Jr., Memorial Laboratory for Cancer Research, Department
of Biochemistry, Chemistry and Pharmacology, Vanderbilt Institute
of Chemical Biology, Center for Molecular Toxicology and Vanderbilt-Ingram
Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Md. Jashim Uddin
- A. B.
Hancock, Jr., Memorial Laboratory for Cancer Research, Department
of Biochemistry, Chemistry and Pharmacology, Vanderbilt Institute
of Chemical Biology, Center for Molecular Toxicology and Vanderbilt-Ingram
Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Ashwath Jayagopal
- Department
of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
- Molecular
Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
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Rattner A, Wang Y, Zhou Y, Williams J, Nathans J. The role of the hypoxia response in shaping retinal vascular development in the absence of Norrin/Frizzled4 signaling. Invest Ophthalmol Vis Sci 2014; 55:8614-25. [PMID: 25414188 DOI: 10.1167/iovs.14-15693] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
PURPOSE To define the role of hypoxia and vascular endothelial growth factor (VEGF) in modifying the pattern, density, and permeability of the retinal vasculature in mouse models in which Norrin/Frizzled4 signaling is impaired. METHODS Retinal vascular structure was analyzed in mice with mutation of Ndp (the gene coding for Norrin) or Frizzle4 (Fz4) with or without three additional perturbations: (1) retinal hyperoxia and reduction of VEGF, (2) reduced induction of VEGF in response to hypoxia, or (3) reduced responsiveness of vascular endothelial cells (ECs) to VEGF. These perturbations were produced, respectively, by (1) genetic ablation of rod photoreceptors in the retinal degeneration 1 (rd1) mutant background, (2) conditional deletion of the gene coding for hypoxia-inducible factor (HIF)-2alpha either in all neural retina cells or specifically in Müller glia, and (3) conditional deletion of the VEGF coreceptor neuropilin1 (NRP1) in ECs. RESULTS All three conditions reduced vascular proliferation. Eliminating HIF2-alpha in Müller glia blocked VEGF induction in the inner nuclear layer, identifying HIF2-alpha as the transcription factor responsible for the hypoxia response in these cells. When Norrin/Frizzled4 signaling was eliminated, a secondary elevation in VEGF levels was required to compromise the barrier to transendothelial movement of high molecular weight compounds. CONCLUSIONS In the absence of Norrin or Frizzled4, the vascular phenotype is determined by the primary defect in Norrin/Frizzled4 signaling (i.e., canonical Wnt signaling) and compensatory responses resulting from hypoxia. This work may be useful in guiding therapeutic strategies for the treatment of familial exudative vitreoretinopathy (FEVR).
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Affiliation(s)
- Amir Rattner
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Yanshu Wang
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Yulian Zhou
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - John Williams
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Jeremy Nathans
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
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Biswal MR, Prentice HM, Dorey CK, Blanks JC. A hypoxia-responsive glial cell-specific gene therapy vector for targeting retinal neovascularization. Invest Ophthalmol Vis Sci 2014; 55:8044-53. [PMID: 25377223 DOI: 10.1167/iovs.14-13932] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
PURPOSE Müller cells, the major glial cell in the retina, play a significant role in retinal neovascularization in response to tissue hypoxia. We previously designed and tested a vector using a hypoxia-responsive domain and a glial fibrillary acidic protein (GFAP) promoter to drive green fluorescent protein (GFP) expression in Müller cells in the murine model of oxygen-induced retinopathy (OIR). This study compares the efficacy of regulated and unregulated Müller cell delivery of endostatin in preventing neovascularization in the OIR model. METHODS Endostatin cDNA was cloned into plasmids with hypoxia-regulated GFAP or unregulated GFAP promoters, and packaged into self-complementary adeno-associated virus serotype 2 vectors (scAAV2). Before placement in hyperoxia on postnatal day (P)7, mice were given intravitreal injections of regulated or unregulated scAAV2, capsid, or PBS. Five days after return to room air, on P17, neovascular and avascular areas, as well as expression of the transgene and vascular endothelial growth factor (VEGF), were compared in OIR animals treated with a vector, capsid, or PBS. RESULTS The hypoxia-regulated, glial-specific, vector-expressing endostatin reduced neovascularization by 93% and reduced the central vaso-obliteration area by 90%, matching the results with the unregulated GFAP-Endo vector. Retinas treated with the regulated endostatin vector expressed substantial amounts of endostatin protein, and significantly reduced VEGF protein. Endostatin production from the regulated vector was undetectable in retinas with undamaged vasculature. CONCLUSIONS These findings suggest that the hypoxia-regulated, glial cell-specific vector expressing endostatin may be useful for treatment of neovascularization in proliferative diabetic retinopathy.
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Affiliation(s)
- Manas R Biswal
- Integrative Biology PhD Program, Florida Atlantic University, Boca Raton, Florida, United States
| | - Howard M Prentice
- Center for Complex Systems and Brain Sciences, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, Florida, United States Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, United States
| | - C Kathleen Dorey
- Virginia Tech Carilion School of Medicine, Roanoke, Virginia, United States
| | - Janet C Blanks
- Center for Complex Systems and Brain Sciences, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, Florida, United States
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Evans SM, Kim K, Moore CE, Uddin MI, Capozzi ME, Craft JR, Sulikowski GA, Jayagopal A. Molecular probes for imaging of hypoxia in the retina. Bioconjug Chem 2014; 25:2030-7. [PMID: 25250692 PMCID: PMC4240343 DOI: 10.1021/bc500400z] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Hypoxia has been associated with retinal diseases which lead the causes of irreversible vision loss, including diabetic retinopathy, retinopathy of prematurity, and age-related macular degeneration. Therefore, technologies for imaging hypoxia in the retina are needed for early disease detection, monitoring of disease progression, and assessment of therapeutic responses in the patient. Toward this goal, we developed two hypoxia-sensitive imaging agents based on nitroimidazoles which are capable of accumulating in hypoxic cells in vivo. 2-nitroimidazole or Pimonidazole was conjugated to fluorescent dyes to yield the imaging agents HYPOX-1 and HYPOX-2. Imaging agents were characterized in cell culture and animal models of retinal vascular diseases which exhibit hypoxia. Both HYPOX-1 and -2 were capable of detecting hypoxia in cell culture models with >10:1 signal-to-noise ratios without acute toxicity. Furthermore, intraocular administration of contrast agents in mouse models of retinal hypoxia enabled ex vivo detection of hypoxic tissue. These imaging agents are a promising step toward translation of hypoxia-sensitive molecular imaging agents in preclinical animal models and patients.
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Affiliation(s)
- Stephanie M Evans
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute , Nashville, Tennessee37232, United States
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Wilkinson-Berka JL, Deliyanti D, Rana I, Miller AG, Agrotis A, Armani R, Szyndralewiez C, Wingler K, Touyz RM, Cooper ME, Jandeleit-Dahm KA, Schmidt HHHW. NADPH oxidase, NOX1, mediates vascular injury in ischemic retinopathy. Antioxid Redox Signal 2014; 20:2726-40. [PMID: 24053718 PMCID: PMC4026404 DOI: 10.1089/ars.2013.5357] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
AIMS Ischemic retinal diseases such as retinopathy of prematurity are major causes of blindness due to damage to the retinal microvasculature. Despite this clinical situation, retinopathy of prematurity is mechanistically poorly understood. Therefore, effective preventative therapies are not available. However, hypoxic-induced increases in reactive oxygen species (ROS) have been suggested to be involved with NADPH oxidases (NOX), the only known dedicated enzymatic source of ROS. Our major aim was to determine the contribution of NOX isoforms (1, 2, and 4) to a rodent model of retinopathy of prematurity. RESULTS Using a genetic approach, we determined that only mice with a deletion of NOX1, but not NOX2 or NOX4, were protected from retinal neovascularization and vaso-obliteration, adhesion of leukocytes, microglial accumulation, and the increased generation of proangiogenic and proinflammatory factors and ROS. We complemented these studies by showing that the specific NOX inhibitor, GKT137831, reduced vasculopathy and ROS levels in retina. The source of NOX isoforms was evaluated in retinal vascular cells and neuro-glial elements. Microglia, the immune cells of the retina, expressed NOX1, 2, and 4 and responded to hypoxia with increased ROS formation, which was reduced by GKT137831. INNOVATION Our studies are the first to identify the NOX1 isoform as having an important role in the pathogenesis of retinopathy of prematurity. CONCLUSIONS Our findings suggest that strategies targeting NOX1 have the potential to be effective treatments for a range of ischemic retinopathies.
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Madamanchi A, Capozzi M, Geng L, Li Z, Friedman RD, Dickeson SK, Penn JS, Zutter MM. Mitigation of oxygen-induced retinopathy in α2β1 integrin-deficient mice. Invest Ophthalmol Vis Sci 2014; 55:4338-47. [PMID: 24917135 DOI: 10.1167/iovs.14-14061] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
PURPOSE The α2β1 integrin plays an important but complex role in angiogenesis and vasculopathies. Published GWAS studies established a correlation between genetic polymorphisms of the α2β1 integrin gene and incidence of diabetic retinopathy. Recent studies indicated that α2-null mice demonstrate superior vascularization in both the wound and diabetic microenvironments. The goal of this study was to determine whether the vasculoprotective effects of α2-integrin deficiency extended to the retina, using the oxygen-induced retinopathy (OIR) model for retinopathy of prematurity (ROP). METHODS In the OIR model, wild-type (WT) and α2-null mice were exposed to 75% oxygen for 5 days (postnatal day [P] 7 to P12) and subsequently returned to room air for 6 days (P12-P18). Retinas were collected at postnatal day 7, day 13, and day 18 and examined via hematoxylin and eosin and Lectin staining. Retinas were analyzed for retinal vascular area, neovascularization, VEGF expression, and Müller cell activation. Primary Müller cell cultures from WT and α2-null mice were isolated and analyzed for hypoxia-induced VEGF-A expression. RESULTS In the retina, the α2β1 integrin was minimally expressed in endothelial cells and strongly expressed in activated Müller cells. Isolated α2-null primary Müller cells demonstrated decreased hypoxia-induced VEGF-A expression. In the OIR model, α2-null mice displayed reduced hyperoxia-induced vaso-attenuation, reduced pathological retinal neovascularization, and decreased VEGF expression as compared to WT counterparts. CONCLUSIONS Our data suggest that the α2β1 integrin contributes to the pathogenesis of retinopathy. We describe a newly identified role for α2β1 integrin in mediating hypoxia-induced Müller cell VEGF-A production.
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Affiliation(s)
- Aasakiran Madamanchi
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Megan Capozzi
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Ling Geng
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Zhengzhi Li
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Richard D Friedman
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - S Kent Dickeson
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - John S Penn
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Mary M Zutter
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
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Fawzi AA, Chou JC, Kim GA, Rollins SD, Taylor JM, Farrow KN. Sildenafil attenuates vaso-obliteration and neovascularization in a mouse model of retinopathy of prematurity. Invest Ophthalmol Vis Sci 2014; 55:1493-501. [PMID: 24519428 DOI: 10.1167/iovs.13-13207] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE We sought to determine the effect of sildenafil on retinal vascular changes in a mouse model of oxygen-induced retinopathy (OIR). METHODS Vascular defects in OIR mice were quantified by measuring vaso-obliteration at postnatal days 12 and 17 (P12 and P17) and neovascularization at P17 to compare sildenafil-treated to dextrose-treated OIR mice. Retinal HIF1α protein expression was quantified by Western blotting and normalized to that of β-actin. Right ventricular hypertrophy was measured by Fulton's index as a surrogate for hyperoxia-induced pulmonary hypertension. RESULTS At P12, OIR mice treated with sildenafil demonstrated a 24% reduction in vaso-obliteration (P < 0.05), whereas at P17, treated animals showed a 50% reduction in neovascularization (P < 0.05) compared to dextrose-treated controls. Sildenafil-treated OIR mice had stabilization of retinal HIF1α at P12, immediately after hyperoxia. At P17, sildenafil-treated OIR mice had decreased HIF1α relative to untreated mice. OIR mice developed right ventricle hypertrophy that was significant compared to that in room air controls, which was abrogated by sildenafil. CONCLUSIONS Sildenafil treatment significantly decreased retinal vaso-obliteration and neovascularization in a mouse OIR model. These effects are likely due to sildenafil-induced HIF1α stabilization during hyperoxia exposure. Furthermore, we confirm disease overlap by showing that OIR mice also develop hyperoxia-induced right ventricular hypertrophy, which is prevented by sildenafil. This study is a first step toward delineating a potential therapeutic role for sildenafil in OIR and further suggests that there may be common pathophysiologic mechanisms underlying hyperoxia-induced retinal and pulmonary vascular disease.
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Affiliation(s)
- Amani A Fawzi
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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Park SW, Kim JH, Kim KE, Jeong MH, Park H, Park B, Suh YG, Park WJ, Kim JH. Beta-lapachone inhibits pathological retinal neovascularization in oxygen-induced retinopathy via regulation of HIF-1α. J Cell Mol Med 2014; 18:875-84. [PMID: 24533641 PMCID: PMC4119393 DOI: 10.1111/jcmm.12235] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 12/19/2013] [Indexed: 11/27/2022] Open
Abstract
Retinal neovascularization in retinopathy of prematurity (ROP) is the most common cause of blindness for children. Despite evidence that hypoxia inducible factor (HIF)-1α -VEGF axis is associated with the pathogenesis of ROP, the inhibitors of HIF-1α have not been established as a therapeutic target in the control of ROP pathophysiology. We investigated the hypothesis that degradation of HIF-1α as a master regulator of angiogenesis in hypoxic condition, using β-lapachone, would confer protection against hypoxia-induced retinopathy without affecting physiological vascular development in mice with oxygen-induced retinopathy (OIR), an animal model of ROP. The effects of β-lapachone were examined after intraocular injection in mice with OIR. Intraocular administration of β-lapachone resulted in significant reduction in hypoxia-induced retinal neovascularization without retinal toxicity or perturbation of developmental retinal angiogenesis. Our results demonstrate that HIF-1α–mediated VEGF expression in OIR is associated with pathological neovascularization, not physiological angiogenesis. Thus, strategies blocking HIF-1α in the developing eye in the pathological hypoxia could serve as a novel therapeutic target for ROP.
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Affiliation(s)
- Sung Wook Park
- Fight against Angiogenesis-Related Blindness Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea; Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul, Korea
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49
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Duan LJ, Takeda K, Fong GH. Hypoxia inducible factor-2α regulates the development of retinal astrocytic network by maintaining adequate supply of astrocyte progenitors. PLoS One 2014; 9:e84736. [PMID: 24475033 PMCID: PMC3903483 DOI: 10.1371/journal.pone.0084736] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Accepted: 11/27/2013] [Indexed: 11/18/2022] Open
Abstract
Here we investigate the role of hypoxia inducible factor (HIF)-2α in coordinating the development of retinal astrocytic and vascular networks. Three Cre mouse lines were used to disrupt floxed Hif-2α, including Rosa26CreERT2, Tie2Cre, and GFAPCre. Global Hif-2α disruption by Rosa26CreERT2 led to reduced astrocytic and vascular development in neonatal retinas, whereas endothelial disruption by Tie2Cre had no apparent effects. Hif-2α deletion in astrocyte progenitors by GFAPCre significantly interfered with the development of astrocytic networks, which failed to reach the retinal periphery and were incapable of supporting vascular development. Perplexingly, the abundance of strongly GFAP+ mature astrocytes transiently increased at P0 before they began to lag behind the normal controls by P3. Pax2+ and PDGFRα+ astrocytic progenitors and immature astrocytes were dramatically diminished at all stages examined. Despite decreased number of astrocyte progenitors, their proliferation index or apoptosis was not altered. The above data can be reconciled by proposing that HIF-2α is required for maintaining the supply of astrocyte progenitors by slowing down their differentiation into non-proliferative mature astrocytes. HIF-2α deficiency in astrocyte progenitors may accelerate their differentiation into astrocytes, a change which greatly interferes with the replenishment of astrocyte progenitors due to insufficient time for proliferation. Rapidly declining progenitor supply may lead to premature cessation of astrocyte development. Given that HIF-2α protein undergoes oxygen dependent degradation, an interesting possibility is that retinal blood vessels may regulate astrocyte differentiation through their oxygen delivery function. While our findings support the consensus that retinal astrocytic template guides vascular development, they also raise the possibility that astrocytic and vascular networks may mutually regulate each other's development, mediated at least in part by HIF-2α.
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Affiliation(s)
- Li-Juan Duan
- The Center for Vascular Biology, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Kotaro Takeda
- The Center for Vascular Biology, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Guo-Hua Fong
- The Center for Vascular Biology, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut, United States of America
- * E-mail:
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Lijkwan MA, Hellingman AA, Bos EJ, van der Bogt KEA, Huang M, Kooreman NG, de Vries MR, Peters HAB, Robbins RC, Hamming JF, Quax PHA, Wu JC. Short hairpin RNA gene silencing of prolyl hydroxylase-2 with a minicircle vector improves neovascularization of hindlimb ischemia. Hum Gene Ther 2014; 25:41-9. [PMID: 24090375 DOI: 10.1089/hum.2013.110] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
In this study, we target the hypoxia inducible factor-1 alpha (HIF-1-alpha) pathway by short hairpin RNA interference therapy targeting prolyl hydroxylase-2 (shPHD2). We use the minicircle (MC) vector technology as an alternative for conventional nonviral plasmid (PL) vectors in order to improve neovascularization after unilateral hindlimb ischemia in a murine model. Gene expression and transfection efficiency of MC and PL, both in vitro and in vivo, were assessed using bioluminescence imaging (BLI) and firefly luciferase (Luc) reporter gene. C57Bl6 mice underwent unilateral electrocoagulation of the femoral artery and gastrocnemic muscle injection with MC-shPHD2, PL-shPHD2, or phosphate-buffered saline (PBS) as control. Blood flow recovery was monitored using laser Doppler perfusion imaging, and collaterals were visualized by immunohistochemistry and angiography. MC-Luc showed a 4.6-fold higher in vitro BLI signal compared with PL-Luc. BLI signals in vivo were 4.3×10(5)±3.3×10(5) (MC-Luc) versus 0.4×10(5)±0.3×10(5) (PL-Luc) at day 28 (p=0.016). Compared with PL-shPHD2 or PBS, MC-shPHD2 significantly improved blood flow recovery, up to 50% from day 3 until day 14 after ischemia induction. MC-shPHD2 significantly increased collateral density and capillary density, as monitored by alpha-smooth muscle actin expression and CD31(+) expression, respectively. Angiography data confirmed the histological findings. Significant downregulation of PHD2 mRNA levels by MC-shPHD2 was confirmed by quantitative polymerase chain reaction. Finally, Western blot analysis confirmed significantly higher levels of HIF-1-alpha protein by MC-shPHD2, compared with PL-shPHD2 and PBS. This study provides initial evidence of a new potential therapeutic approach for peripheral artery disease. The combination of HIF-1-alpha pathway targeting by shPHD2 with the robust nonviral MC plasmid improved postischemic neovascularization, making this approach a promising potential treatment option for critical limb ischemia.
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Affiliation(s)
- Maarten A Lijkwan
- 1 Department of Medicine and Radiology, Stanford University School of Medicine , Stanford, CA 94305
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