51
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Wei Y, Gong J, Xu Z, Duh EJ. Nrf2 promotes reparative angiogenesis through regulation of NADPH oxidase-2 in oxygen-induced retinopathy. Free Radic Biol Med 2016; 99:234-243. [PMID: 27521459 PMCID: PMC8565612 DOI: 10.1016/j.freeradbiomed.2016.08.013] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 08/01/2016] [Accepted: 08/09/2016] [Indexed: 12/11/2022]
Abstract
Revascularization of ischemic tissue is a highly desirable outcome in multiple diseases, including cardiovascular diseases and ischemic retinopathies. Oxidative stress and inflammation are both known to play a role in suppressing reparative angiogenesis in ischemic disease models including oxygen-induced retinopathy (OIR), but the regulatory molecules governing these pathophysiologic processes in retinal ischemia are largely unknown. Nrf2 is a major stress-response transcription factor that has been implicated in regulating ischemic angiogenesis in the retina and other tissue beds. Using Nrf2-deficient mice, we investigated the effects of Nrf2 in regulating revascularization and modulating the retinal tissue milieu during ischemia. Strikingly, Nrf2's beneficial effect on reparative angiogenesis only became manifested in the later phase of ischemia in OIR, from postnatal day 14 (P14) to P17. This was temporally associated with a reduction in both oxidative stress and inflammatory mediators in wild-type compared to Nrf2-/- mice. Nrf2-/- retinas exhibited an increase in VEGF but also induction of anti-angiogenic Dll4/Notch signaling. NADPH oxidase (NOX), and especially NOX2, is a major pathogenic molecule and a particularly important contributor to oxidative stress in multiple retinal disease processes. Nrf2-/- mice exhibited a significant exacerbation of NOX2 induction in OIR that manifested in the later phases of ischemia. Pharmacologic inhibition of NADPH oxidase abrogated the adverse effect of Nrf2 deficiency on reparative angiogenesis. Taken together, this suggests that Nrf2 is an important regulator of the retinal milieu during tissue ischemia, and that the Nrf2/NOX2 balance may play a critical role in determining the fate of ischemic revascularization.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Animals
- Animals, Newborn
- Calcium-Binding Proteins
- Gene Expression Regulation
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/metabolism
- Ischemia/genetics
- Ischemia/metabolism
- Ischemia/pathology
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- NADPH Oxidase 2/genetics
- NADPH Oxidase 2/metabolism
- NF-E2-Related Factor 2/deficiency
- NF-E2-Related Factor 2/genetics
- Neovascularization, Pathologic/chemically induced
- Neovascularization, Pathologic/genetics
- Neovascularization, Pathologic/metabolism
- Neovascularization, Pathologic/pathology
- Oxidative Stress
- Oxygen/adverse effects
- Receptors, Notch/genetics
- Receptors, Notch/metabolism
- Retina/drug effects
- Retina/metabolism
- Retina/pathology
- Retinitis/chemically induced
- Retinitis/genetics
- Retinitis/metabolism
- Retinitis/pathology
- Signal Transduction
- Vascular Endothelial Growth Factor A/genetics
- Vascular Endothelial Growth Factor A/metabolism
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Affiliation(s)
- Yanhong Wei
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Junsong Gong
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zhenhua Xu
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Elia J Duh
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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52
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Moran EP, Wang Z, Chen J, Sapieha P, Smith LEH, Ma JX. Neurovascular cross talk in diabetic retinopathy: Pathophysiological roles and therapeutic implications. Am J Physiol Heart Circ Physiol 2016; 311:H738-49. [PMID: 27473938 DOI: 10.1152/ajpheart.00005.2016] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 07/18/2016] [Indexed: 12/19/2022]
Abstract
Diabetic retinopathy (DR) is the leading cause of blindness in the working-age population in developed countries, and its prevalence will increase as the global incidence of diabetes grows exponentially. DR begins with an early nonproliferative stage in which retinal blood vessels and neurons degenerate as a consequence of chronic hyperglycemia, resulting in vasoregression and persistent retinal ischemia, metabolic disequilibrium, and inflammation. This is conducive to overcompensatory pathological neovascularization associated with advanced proliferative DR. Although DR is considered a microvascular complication, the retinal microvasculature is intimately associated with and governed by neurons and glia; neurodegeneration, neuroinflammation, and dysregulation of neurovascular cross talk are responsible in part for vascular abnormalities in both early nonproliferative DR and advanced proliferative DR. Neuronal activity directly regulates microvascular dilation and blood flow in the process of neurovascular coupling. Retinal neurons also secrete guidance cues in response to injury, ischemia, or metabolic stress that may either promote or suppress vascular outgrowth, either alleviating or exacerbating DR, contingent on the stage of disease and retinal microenvironment. Neurodegeneration, impaired neurovascular coupling, and dysregulation of neuronal guidance cues are key events in the pathogenesis of DR, and correcting these events may prevent or delay development of advanced DR. The review discusses the mechanisms of neurovascular cross talk and its dysregulation in DR, and their potential therapeutic implications.
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Affiliation(s)
- Elizabeth P Moran
- Depatment of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; Harold Hamm Diabetes Center, Oklahoma City, Oklahoma
| | - Zhongxiao Wang
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; and
| | - Jing Chen
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; and
| | - Przemyslaw Sapieha
- Departments of Ophthalmology, Biochemistry & Molecular Medicine, Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, Montreal, Quebec, Canada
| | - Lois E H Smith
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; and
| | - Jian-Xing Ma
- Depatment of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; Harold Hamm Diabetes Center, Oklahoma City, Oklahoma;
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53
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Miloudi K, Binet F, Wilson A, Cerani A, Oubaha M, Menard C, Henriques S, Mawambo G, Dejda A, Nguyen PT, Rezende FA, Bourgault S, Kennedy TE, Sapieha P. Truncated netrin-1 contributes to pathological vascular permeability in diabetic retinopathy. J Clin Invest 2016; 126:3006-22. [PMID: 27400127 DOI: 10.1172/jci84767] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 05/12/2016] [Indexed: 12/31/2022] Open
Abstract
Diabetic retinopathy (DR) is a major complication of diabetes and a leading cause of blindness in the working-age population. Impaired blood-retinal barrier function leads to macular edema that is closely associated with the deterioration of central vision. We previously demonstrated that the neuronal guidance cue netrin-1 activates a program of reparative angiogenesis in microglia within the ischemic retina. Here, we provide evidence in both vitreous humor of diabetic patients and in retina of a murine model of diabetes that netrin-1 is metabolized into a bioactive fragment corresponding to domains VI and V of the full-length molecule. In contrast to the protective effects of full-length netrin-1 on retinal microvasculature, the VI-V fragment promoted vascular permeability through the uncoordinated 5B (UNC5B) receptor. The collagenase matrix metalloprotease 9 (MMP-9), which is increased in patients with diabetic macular edema, was capable of cleaving netrin-1 into the VI-V fragment. Thus, MMP-9 may release netrin-1 fragments from the extracellular matrix and facilitate diffusion. Nonspecific inhibition of collagenases or selective inhibition of MMP-9 decreased pathological vascular permeability in a murine model of diabetic retinal edema. This study reveals that netrin-1 degradation products are capable of modulating vascular permeability, suggesting that these fragments are of potential therapeutic interest for the treatment of DR.
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54
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Nrf2 in ischemic neurons promotes retinal vascular regeneration through regulation of semaphorin 6A. Proc Natl Acad Sci U S A 2015; 112:E6927-36. [PMID: 26621751 DOI: 10.1073/pnas.1512683112] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Delayed revascularization of ischemic neural tissue is a major impediment to preservation of function in central nervous system (CNS) diseases including stroke and ischemic retinopathies. Therapeutic strategies allowing rapid revascularization are greatly needed to reduce ischemia-induced cellular damage and suppress harmful pathologic neovascularization. However, key mechanisms governing vascular recovery in ischemic CNS, including regulatory molecules governing the transition from tissue injury to tissue repair, are largely unknown. NF-E2-related factor 2 (Nrf2) is a major stress-response transcription factor well known for its cell-intrinsic cytoprotective function. However, its role in cell-cell crosstalk is less appreciated. Here we report that Nrf2 is highly activated in ischemic retina and promotes revascularization by modulating neurons in their paracrine regulation of endothelial cells. Global Nrf2 deficiency strongly suppresses retinal revascularization and increases pathologic neovascularization in a mouse model of ischemic retinopathy. Conditional knockout studies demonstrate a major role for neuronal Nrf2 in vascular regrowth into avascular retina. Deletion of neuronal Nrf2 results in semaphorin 6A (Sema6A) induction in hypoxic/ischemic retinal ganglion cells in a hypoxia-inducible factor-1 alpha (HIF-1α)-dependent fashion. Sema6A expression increases in avascular inner retina and colocalizes with Nrf2 in human fetal eyes. Extracellular Sema6A leads to dose-dependent suppression of the migratory phenotype of endothelial cells through activation of Notch signaling. Lentiviral-mediated delivery of Sema6A small hairpin RNA (shRNA) abrogates the defective retinal revascularization in Nrf2-deficient mice. Importantly, pharmacologic Nrf2 activation promotes reparative angiogenesis and suppresses pathologic neovascularization. Our findings reveal a unique function of Nrf2 in reprogramming ischemic tissue toward neurovascular repair via Sema6A regulation, providing a potential therapeutic strategy for ischemic retinal and CNS diseases.
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55
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Abstract
Proper tissue vascularization is vital for cellular function as it delivers oxygen, nutrients, hormones, and immune cells and helps to clear cellular debris and metabolic waste products. Tissue angiogenesis occurs to satisfy energy requirements and cellular sensors of metabolic imbalance coordinate vessel growth. In this regard, the classical pathways of the unfolded protein response activated under conditions of ER stress have recently been described to generate angiomodulatory or angiostatic signals. This review elaborates on the link between angiogenesis and ER stress and discusses the implications for diseases characterized by altered vascular homeostasis, such as cancer, retinopathies, and atherosclerosis.
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Affiliation(s)
- François Binet
- Departments of Ophthalmology, Biochemistry, & Molecular Medicine, Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, Montreal, QC H1T 2M4, Canada
| | - Przemyslaw Sapieha
- Departments of Ophthalmology, Biochemistry, & Molecular Medicine, Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, Montreal, QC H1T 2M4, Canada; Department of Neurology-Neurosurgery, McGill University, Montreal, QC H3A 2B4, Canada.
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56
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Economopoulou M, Avramovic N, Klotzsche-von Ameln A, Korovina I, Sprott D, Samus M, Gercken B, Troullinaki M, Grossklaus S, Funk RH, Li X, Imhof BA, Orlova VV, Chavakis T. Endothelial-specific deficiency of Junctional Adhesion Molecule-C promotes vessel normalisation in proliferative retinopathy. Thromb Haemost 2015; 114:1241-9. [PMID: 26311310 DOI: 10.1160/th15-01-0051] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 07/09/2015] [Indexed: 12/29/2022]
Abstract
In proliferative retinopathies, like proliferative diabetic retinopathy and retinopathy of prematurity (ROP), the hypoxia response is sustained by the failure of the retina to revascularise its ischaemic areas. Non-resolving retina ischaemia/hypoxia results in upregulation of pro-angiogenic factors and pathologic neovascularisation with ectopic, fragile neovessels. Promoting revascularisation of the retinal avascular area could interfere with this vicious cycle and lead to vessel normalisation. Here, we examined the function of endothelial junctional adhesion molecule-C (JAM-C) in the context of ROP. Endothelial-specific JAM-C-deficient (EC-JAM-C KO) mice and littermate JAM-C-proficient (EC-JAM-C WT) mice were subjected to the ROP model. An increase in total retinal vascularisation was found at p17 owing to endothelial JAM-C deficiency, which was the result of enhanced revascularisation and vessel normalisation, thereby leading to significantly reduced avascular area in EC-JAM-C KO mice. In contrast, pathologic neovessel formation was not affected by endothelial JAM-C deficiency. Consistent with improved vessel normalisation, tip cell formation at the interface between vascular and avascular area was higher in EC-JAM-C KO mice, as compared to their littermate controls. Consistently, JAM-C inactivation in endothelial cells resulted in increased spreading on fibronectin and enhanced sprouting in vitro in a manner dependent on β1-integrin and on the activation of the small GTPase RAP1. Together, endothelial deletion of JAM-C promoted endothelial cell sprouting, and consequently vessel normalisation and revascularisation of the hypoxic retina without altering pathologic neovascularisation. Thus, targeting endothelial JAM-C may provide a novel therapeutic strategy for promoting revascularisation and vessel normalisation in the treatment of proliferative retinopathies.
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Affiliation(s)
- Matina Economopoulou
- Matina Economopoulou, Department of Ophthalmology, Univ. Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany, Tel.: +49 351 45819291, E-mail:
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57
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Johnson V, Xiang M, Chen Z, Junge HJ. Neurite Mistargeting and Inverse Order of Intraretinal Vascular Plexus Formation Precede Subretinal Vascularization in Vldlr Mutant Mice. PLoS One 2015; 10:e0132013. [PMID: 26177550 PMCID: PMC4503745 DOI: 10.1371/journal.pone.0132013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 06/09/2015] [Indexed: 02/07/2023] Open
Abstract
In the retina blood vessels are required to support a high metabolic rate, however, uncontrolled vascular growth can lead to impaired vision and blindness. Subretinal vascularization (SRV), one type of pathological vessel growth, occurs in retinal angiomatous proliferation and proliferative macular telangiectasia. In these diseases SRV originates from blood vessels within the retina. We use mice with a targeted disruption in the Vldl-receptor (Vldlr) gene as a model to study SRV with retinal origin. We find that Vldlr mRNA is strongly expressed in the neuroretina, and we observe both vascular and neuronal phenotypes in Vldlr-/- mice. Unexpectedly, horizontal cell (HC) neurites are mistargeted prior to SRV in this model, and the majority of vascular lesions are associated with mistargeted neurites. In Foxn4-/- mice, which lack HCs and display reduced amacrine cell (AC) numbers, we find severe defects in intraretinal capillary development. However, SRV is not suppressed in Foxn4-/-;Vldlr-/- mice, which reveals that mistargeted HC neurites are not required for vascular lesion formation. In the absence of VLDLR, the intraretinal capillary plexuses form in an inverse order compared to normal development, and subsequent to this early defect, vascular proliferation is increased. We conclude that SRV in the Vldlr-/- model is associated with mistargeted neurites and that SRV is preceded by altered retinal vascular development.
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Affiliation(s)
- Verity Johnson
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado, 80309, United States of America
| | - Mengqing Xiang
- Center for Advanced Biotechnology and Medicine and Department of Pediatrics, Rutgers University-Robert Wood Johnson Medical School, Piscataway, New Jersey, 08901, United States of America
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 South Xianlie Road, Guangzhou, 510060, China
| | - Zhe Chen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado, 80309, United States of America
| | - Harald J. Junge
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado, 80309, United States of America
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58
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Trost A, Motloch K, Bruckner D, Schroedl F, Bogner B, Kaser-Eichberger A, Runge C, Strohmaier C, Klein B, Aigner L, Reitsamer HA. Time-dependent retinal ganglion cell loss, microglial activation and blood-retina-barrier tightness in an acute model of ocular hypertension. Exp Eye Res 2015; 136:59-71. [PMID: 26001526 DOI: 10.1016/j.exer.2015.05.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 05/18/2015] [Accepted: 05/19/2015] [Indexed: 02/04/2023]
Abstract
Glaucoma is a group of neurodegenerative diseases characterized by the progressive loss of retinal ganglion cells (RGCs) and their axons, and is the second leading cause of blindness worldwide. Elevated intraocular pressure is a well known risk factor for the development of glaucomatous optic neuropathy and pharmacological or surgical lowering of intraocular pressure represents a standard procedure in glaucoma treatment. However, the treatment options are limited and although lowering of intraocular pressure impedes disease progression, glaucoma cannot be cured by the currently available therapy concepts. In an acute short-term ocular hypertension model in rat, we characterize RGC loss, but also microglial cell activation and vascular alterations of the retina at certain time points. The combination of these three parameters might facilitate a better evaluation of the disease progression, and could further serve as a new model to test novel treatment strategies at certain time points. Acute ocular hypertension (OHT) was induced by the injection of magnetic microbeads into the rat anterior chamber angle (n = 22) with magnetic position control, leading to constant elevation of IOP. At certain time points post injection (4d, 7d, 10d, 14d and 21d), RGC loss, microglial activation, and microvascular pericyte (PC) coverage was analyzed using immunohistochemistry with corresponding specific markers (Brn3a, Iba1, NG2). Additionally, the tightness of the retinal vasculature was determined via injections of Texas Red labeled dextran (10 kDa) and subsequently analyzed for vascular leakage. For documentation, confocal laser-scanning microscopy was used, followed by cell counts, capillary length measurements and morphological and statistical analysis. The injection of magnetic microbeads led to a progressive loss of RGCs at the five time points investigated (20.07%, 29.52%, 41.80%, 61.40% and 76.57%). Microglial cells increased in number and displayed an activated morphology, as revealed by Iba1-positive cell number (150.23%, 175%, 429.25%,486.72% and 544.78%) and particle size analysis (205.49%, 203.37%, 412.84%, 333.37% and 299.77%) compared to contralateral control eyes. Pericyte coverage (NG2-positive PC/mm) displayed a significant reduction after 7d of OHT in central, and after 7d and 10d in peripheral retina. Despite these alterations, the tightness of the retinal vasculature remained unaltered at 14 and 21 days after OHT induction. While vascular tightness was unchanged in the course of OHT, a progressive loss of RGCs and activation of microglial cells was detected. Since a significant loss in RGCs was observed already at day 4 of experimental glaucoma, and since activated microglia peaked at day 10, we determined a time frame of 7-14 days after MB injection as potential optimum to study glaucoma mechanisms in this model.
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Affiliation(s)
- A Trost
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria; Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria
| | - K Motloch
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria
| | - D Bruckner
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria
| | - F Schroedl
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria; Anatomy, Paracelsus Medical University, Salzburg, Austria
| | - B Bogner
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria
| | - A Kaser-Eichberger
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria
| | - C Runge
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria
| | - C Strohmaier
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria
| | - B Klein
- Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University Salzburg, Austria
| | - L Aigner
- Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University Salzburg, Austria
| | - H A Reitsamer
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University Salzburg, Austria.
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59
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SanGiovanni JP, Chen J, Gupta AS, Smith LEH, Sapieha P, Lee PH. Netrin-1 - DCC Signaling Systems and Age-Related Macular Degeneration. PLoS One 2015; 10:e0125548. [PMID: 25950802 PMCID: PMC4423995 DOI: 10.1371/journal.pone.0125548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 03/25/2015] [Indexed: 01/04/2023] Open
Abstract
We conducted a nested candidate gene study and pathway-based enrichment analysis on data from a multi-national 77,000-person project on the molecular genetics of age-related macular degeneration (AMD) to identify AMD-associated DNA-sequence variants in genes encoding constituents of a netrin-1 (NTN1)-based signaling pathway that converges on DNA-binding transcription complexes through a 3'-5'-cyclic adenosine monophosphate-calcineurin (cAMP-CN)-dependent axis. AMD-associated single nucleotide polymorphisms (SNPs) existed in 9 linkage disequilibrium-independent genomic regions; these included loci overlapping NTN1 (rs9899630, P ≤ 9.48 x 10-5), DCC (Deleted in Colorectal Cancer)—the gene encoding a primary NTN1 receptor (rs8097127, P ≤ 3.03 x 10-5), and 6 other netrin-related genes. Analysis of the NTN1-DCC pathway with exact methods demonstrated robust enrichment with AMD-associated SNPs (corrected P-value = 0.038), supporting the idea that processes driven by NTN1-DCC signaling systems operate in advanced AMD. The NTN1-DCC pathway contains targets of FDA-approved drugs and may offer promise for guiding applied clinical research on preventive and therapeutic interventions for AMD.
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Affiliation(s)
- John Paul SanGiovanni
- National Institute of Alcohol Abuse and Alcoholism, Section on Nutritional Neuroscience, National Institutes of Health, Bethesda, MD, United States of America
- * E-mail:
| | - Jing Chen
- Department of Ophthalmology, Harvard Medical School, Boston Children’s Hospital, Boston, MA, United States of America
| | - Ankur S. Gupta
- University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Lois E. H. Smith
- Department of Ophthalmology, Harvard Medical School, Boston Children’s Hospital, Boston, MA, United States of America
| | - Przemyslaw Sapieha
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, Montreal, QC, Canada
| | - Phil H. Lee
- Analytic & Translational Genetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States of America
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60
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Artham S, Fouda AY, El-Remessy AB, Fagan SC. Vascular protective effects of Angiotensin Receptor Blockers: Beyond Blood pressure. ACTA ACUST UNITED AC 2015; 2. [PMID: 26317114 DOI: 10.14800/rci.774] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Sandeep Artham
- Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, and Georgia Regents University, Charlie Norwood VA Medical Center, Augusta, GA, USA
| | - Abdelrahman Y Fouda
- Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, and Georgia Regents University, Charlie Norwood VA Medical Center, Augusta, GA, USA
| | - Azza B El-Remessy
- Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, and Georgia Regents University, Charlie Norwood VA Medical Center, Augusta, GA, USA
| | - Susan C Fagan
- Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, and Georgia Regents University, Charlie Norwood VA Medical Center, Augusta, GA, USA
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61
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Usui Y, Westenskow PD, Kurihara T, Aguilar E, Sakimoto S, Paris LP, Wittgrove C, Feitelberg D, Friedlander MSH, Moreno SK, Dorrell MI, Friedlander M. Neurovascular crosstalk between interneurons and capillaries is required for vision. J Clin Invest 2015; 125:2335-46. [PMID: 25915585 DOI: 10.1172/jci80297] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 03/19/2015] [Indexed: 12/21/2022] Open
Abstract
Functional interactions between neurons, vasculature, and glia within neurovascular units are critical for maintenance of the retina and other CNS tissues. For example, the architecture of the neurosensory retina is a highly organized structure with alternating layers of neurons and blood vessels that match the metabolic demand of neuronal activity with an appropriate supply of oxygen within perfused blood. Here, using murine genetic models and cell ablation strategies, we have demonstrated that a subset of retinal interneurons, the amacrine and horizontal cells, form neurovascular units with capillaries in 2 of the 3 retinal vascular plexuses. Moreover, we determined that these cells are required for generating and maintaining the intraretinal vasculature through precise regulation of hypoxia-inducible and proangiogenic factors, and that amacrine and horizontal cell dysfunction induces alterations to the intraretinal vasculature and substantial visual deficits. These findings demonstrate that specific retinal interneurons and the intraretinal vasculature are highly interdependent, and loss of either or both elicits profound effects on photoreceptor survival and function.
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62
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Hu JZ, Long H, Wu TD, Zhou Y, Lu HB. The effect of estrogen-related receptor α on the regulation of angiogenesis after spinal cord injury. Neuroscience 2015; 290:570-80. [PMID: 25665753 DOI: 10.1016/j.neuroscience.2015.01.067] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 01/29/2015] [Accepted: 01/29/2015] [Indexed: 01/08/2023]
Abstract
Estrogen receptor-related receptor-α (ERRα) is an orphan member of the nuclear receptor superfamily that interacts with peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) to stimulate vascular endothelial growth factor (VEGF) expression and angiogenesis in a hypoxia-inducible factor-1α-independent pathway. Although it is not regulated by any natural ligand, the action of ERRα can be blocked by the synthetic molecule XCT790. In the present study, Sprague-Dawley rats were randomly allocated to a sham group, injury-saline group or injury-XCT90 group. A modified Allen's weight-drop method was applied to induce the acute traumatic spinal cord injury (SCI) model in these rats, and an injection of XCT790 was administered every 24h, starting half an hour after the SCI contusion. Histological analyses revealed that XCT790 significantly aggravated tissue damage and decreased the number of ERRα-positive cells at 1, 3 and 7 days after SCI. Western blot and quantitative real-time polymerase chain reaction (qRT-PCR) analyses also indicated that XCT790 dramatically repressed the expression of ERRα, thus reducing the expression of VEGF and angiopoietin-2 (Ang-2) throughout the duration of the experiment, but the expression of PGC-1α was not affected. Immunofluorescence analyses indicated that vascular density and endothelial cell proliferation were decreased in the injury-XCT90 group compared with the injury-saline group. These results suggest that ERRα is involved in mediating angiogenesis after SCI in the rat traumatic SCI model.
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Affiliation(s)
- J Z Hu
- Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha 410008, PR China
| | - H Long
- Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha 410008, PR China
| | - T-D Wu
- Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha 410008, PR China
| | - Y Zhou
- Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha 410008, PR China
| | - H-B Lu
- Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha 410008, PR China.
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Combined effect of insulin-like growth factor-1 and CC chemokine ligand 2 on angiogenic events in endothelial cells. PLoS One 2015; 10:e0121249. [PMID: 25830234 PMCID: PMC4382320 DOI: 10.1371/journal.pone.0121249] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 01/29/2015] [Indexed: 12/31/2022] Open
Abstract
Therapeutic angiogenesis may be applied in medical conditions to promote stimulation of angiogenesis. Angiogenesis is a multistep process, which includes endothelial cell proliferation, migration, and tube formation, which is mediated by various angiogenic polypeptides. Thus, studies that elucidate the cellular mechanisms involved in these processes are necessary to develop novel therapeutic strategies. This study investigated the in vitro effects of the pro-angiogenic factors, insulin-like growth factor-1 (IGF-1) and/or chemokine (CC motif) ligand 2 (CCL2), on endothelial cells. Flow cytometry analysis showed that IGF-1 and CCL2 treatment did not interfere with IGF-1 receptor (IGF-1R) expression, but CCL2 treatment increased CCL2 receptor (CCR2) expression. Immunofluorescence analysis revealed that the IGF-1/CCL2 combination induced a greater increase in fibronectin deposition, but the treatments did not alter the expression of the fibronectin receptors, CD49e and CD44. The interaction of fibronectin with cytokines demonstrated that IGF-1/CCL2 promoted changes in intermediate F-actin remodeling that may result in increased endothelial cell adhesion and cell migration mediated by fibronectin. Furthermore, IGF-1/CCL2 stimulated endothelial cells, grown on fibronectin, to form capillary-like structures and intercellular lumina with greater luminal area. These data suggest that IGF-1/CCL2 combination and a fibronectin matrix may contribute to the angiogenesis process to stimulate adhesion, migration, and tube formation by endothelial cells as a result of F-actin remodeling.
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Paris LP, Usui Y, Serino J, Sá J, Friedlander M. A Challenging Form of Non-autoimmune Insulin-Dependent Diabetes in a Wolfram Syndrome Patient with a Novel Sequence Variant. ACTA ACUST UNITED AC 2015; 6:1-5. [PMID: 26819810 PMCID: PMC4725320 DOI: 10.4172/2155-6156.1000561] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Wolfram syndrome type 1 is a rare, autosomal recessive, neurodegenerative disorder that is diagnosed when insulin-dependent diabetes of non-auto-immune origin and optic atrophy are concomitantly present. Wolfram syndrome is also designated by DIDMOAD that stands for its most frequent manifestations: diabetes insipidus, diabetes mellitus, optic atrophy and deafness. With disease progression, patients also commonly develop severe neurological and genito-urinary tract abnormalities. When compared to the general type 1 diabetic population, patients with Wolfram Syndrome have been reported to have a form of diabetes that is more easily controlled and with less microvascular complications, such as diabetic retinopathy. We report a case of Wolfram syndrome in a 16-year-old male patient who presented with progressive optic atrophy and severe diabetes with very challenging glycemic control despite intensive therapy since diagnosis at the age of 6. Despite inadequate metabolic control he did not develop any diabetic microvascular complications during the 10-year follow-up period. To further investigate potential causes for this metabolic idiosyncrasy, we performed genetic analyses that revealed a novel combination of homozygous sequence variants that are likely the cause of the syndrome in this family. The identified genotype included a novel sequence variant in the Wolfram syndrome type 1 gene along with a previously described one, which had initially been associated with isolated low frequency sensorineural hearing loss (LFSNHL). Interestingly, our patient did not show any abnormal findings with audiometry testing.
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Affiliation(s)
- Liliana P Paris
- Department of Cell and Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Yoshihiko Usui
- Department of Cell and Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Josefina Serino
- Ophthalmology Department, Hospital Pedro Hispano, Matosinhos - Greater Oporto area, Portugal
| | | | - Martin Friedlander
- Department of Cell and Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Sene A, Chin-Yee D, Apte RS. Seeing through VEGF: innate and adaptive immunity in pathological angiogenesis in the eye. Trends Mol Med 2015; 21:43-51. [PMID: 25457617 PMCID: PMC4282831 DOI: 10.1016/j.molmed.2014.10.005] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 10/01/2014] [Accepted: 10/14/2014] [Indexed: 12/19/2022]
Abstract
The central role of vascular endothelial growth factor (VEGF) signaling in regulating normal vascular development and pathological angiogenesis has been documented in multiple studies. Ocular anti-VEGF therapy is highly effective for treating a subset of patients with blinding eye disorders such as diabetic retinopathy and neovascular age-related macular degeneration (AMD). However, chronic VEGF suppression can lead to adverse effects associated with poor visual outcomes due to the loss of prosurvival and neurotrophic capacities of VEGF. In this review, we discuss emerging evidence for immune-related mechanisms that regulate ocular angiogenesis in a VEGF-independent manner. These novel molecular and cellular pathways may provide potential therapeutic avenues for a multitarget strategy, preserving the neuroprotective functions of VEGF in those patients whose disease is unresponsive to VEGF neutralization.
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Affiliation(s)
- Abdoulaye Sene
- Department of Ophthalmology, Washington University School of Medicine, St Louis, MO, USA.
| | - David Chin-Yee
- Department of Ophthalmology, Washington University School of Medicine, St Louis, MO, USA
| | - Rajendra S Apte
- Department of Ophthalmology, Washington University School of Medicine, St Louis, MO, USA; Department of Developmental Biology, Washington University School of Medicine, St Louis, MO, USA; Neuroscience Program, Washington University School of Medicine, St Louis, MO, USA.
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66
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Shanab AY, Elshaer SL, El-Azab MF, Soliman S, Sabbineni H, Matragoon S, Fagan SC, El-Remessy AB. Candesartan stimulates reparative angiogenesis in ischemic retinopathy model: role of hemeoxygenase-1 (HO-1). Angiogenesis 2014; 18:137-50. [PMID: 25420481 DOI: 10.1007/s10456-014-9451-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 11/12/2014] [Indexed: 02/06/2023]
Abstract
Ischemic diseases such as stroke and proliferative retinopathy are characterized by hypoxia-driven release of angiogenic factors such as vascular endothelial growth factor (VEGF). However, revascularization of the ischemic areas is inadequate, resulting in impaired neuro-vascular function. We aim to examine the vascular protective effects of candesartan, an angiotensin receptor blocker, in an ischemic retinopathy mouse model. Vascular density, number of tip cells, and perfusions of capillaries were assessed. Activation of Muller glial cells and levels of peroxynitrite, VEGF, VEGFR2, inducible nitric oxide synthase, hemeoxygenase-1 (HO-1) were assessed. Proangiogenic effects of candesartan were examined in human endothelial cells (EC) that were cultured in normoxia or hypoxia and transduced with siRNA against HO-1. Candesartan (1 mg/kg) and (10 mg/kg) decreased hypoxia-induced neovascularization by 67 and 70%, respectively. Candesartan (10 mg/kg) significantly stimulated the number of tip cells and physiological revascularization of the central retina (45%) compared with untreated pups. The effects of candesartan coincided with reduction of hypoxia-induced Muller glial activation, iNOS expression and restoration of HO-1 expression with no significant change in VEGF levels. In vitro, silencing HO-1 expression blunted the ability of candesartan to induce VEGF expression under normoxia and VEGFR2 activation and angiogenic response under both normoxia and hypoxia. These findings suggest that candesartan improved reparative angiogenesis and hence prevented pathological angiogenesis by modulating HO-1 and iNOS levels in ischemic retinopathy. HO-1 is required for VEGFR2 activation and proangiogenic action of candesartan in EC. Candesartan, an FDA-approved drug, could be repurposed as a potential therapeutic agent for the treatment of ischemic diseases.
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Affiliation(s)
- Ahmed Y Shanab
- Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA, 30912, USA
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Dejda A, Mawambo G, Cerani A, Miloudi K, Shao Z, Daudelin JF, Boulet S, Oubaha M, Beaudoin F, Akla N, Henriques S, Menard C, Stahl A, Delisle JS, Rezende FA, Labrecque N, Sapieha P. Neuropilin-1 mediates myeloid cell chemoattraction and influences retinal neuroimmune crosstalk. J Clin Invest 2014; 124:4807-22. [PMID: 25271625 DOI: 10.1172/jci76492] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 08/28/2014] [Indexed: 12/28/2022] Open
Abstract
Immunological activity in the CNS is largely dependent on an innate immune response and is heightened in diseases, such as diabetic retinopathy, multiple sclerosis, amyotrophic lateral sclerosis, and Alzheimer's disease. The molecular dynamics governing immune cell recruitment to sites of injury and disease in the CNS during sterile inflammation remain poorly defined. Here, we identified a subset of mononuclear phagocytes (MPs) that responds to local chemotactic cues that are conserved among central neurons, vessels, and immune cells. Patients suffering from late-stage proliferative diabetic retinopathy (PDR) had elevated vitreous semaphorin 3A (SEMA3A). Using a murine model, we found that SEMA3A acts as a potent attractant for neuropilin-1-positive (NRP-1-positive) MPs. These proangiogenic MPs were selectively recruited to sites of pathological neovascularization in response to locally produced SEMA3A as well as VEGF. NRP-1-positive MPs were essential for disease progression, as NRP-1-deficient MPs failed to enter the retina in a murine model of oxygen-induced retinopathy (OIR), a proxy for PDR. OIR mice with NRP-1-deficient MPs exhibited decreased vascular degeneration and diminished pathological preretinal neovascularization. Intravitreal administration of a NRP-1-derived trap effectively mimicked the therapeutic benefits observed in mice lacking NRP-1-expressing MPs. Our findings indicate that NRP-1 is an obligate receptor for MP chemotaxis, bridging neural ischemia to an innate immune response in neovascular retinal disease.
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68
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Yuen TJ, Silbereis JC, Griveau A, Chang SM, Daneman R, Fancy SPJ, Zahed H, Maltepe E, Rowitch DH. Oligodendrocyte-encoded HIF function couples postnatal myelination and white matter angiogenesis. Cell 2014; 158:383-396. [PMID: 25018103 DOI: 10.1016/j.cell.2014.04.052] [Citation(s) in RCA: 275] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Revised: 03/13/2014] [Accepted: 04/22/2014] [Indexed: 12/30/2022]
Abstract
Myelin sheaths provide critical functional and trophic support for axons in white matter tracts of the brain. Oligodendrocyte precursor cells (OPCs) have extraordinary metabolic requirements during development as they differentiate to produce multiple myelin segments, implying that they must first secure adequate access to blood supply. However, mechanisms that coordinate myelination and angiogenesis are unclear. Here, we show that oxygen tension, mediated by OPC-encoded hypoxia-inducible factor (HIF) function, is an essential regulator of postnatal myelination. Constitutive HIF1/2α stabilization resulted in OPC maturation arrest through autocrine activation of canonical Wnt7a/7b. Surprisingly, such OPCs also show paracrine activity that induces excessive postnatal white matter angiogenesis in vivo and directly stimulates endothelial cell proliferation in vitro. Conversely, OPC-specific HIF1/2α loss of function leads to insufficient angiogenesis in corpus callosum and catastrophic axon loss. These findings indicate that OPC-intrinsic HIF signaling couples postnatal white matter angiogenesis, axon integrity, and the onset of myelination in mammalian forebrain.
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Affiliation(s)
- Tracy J Yuen
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine and Howard Hughes Medical Institute, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | - John C Silbereis
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine and Howard Hughes Medical Institute, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA; Neuroscience Graduate Program, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Amelie Griveau
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine and Howard Hughes Medical Institute, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Sandra M Chang
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine and Howard Hughes Medical Institute, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Richard Daneman
- Department of Anatomy, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Stephen P J Fancy
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine and Howard Hughes Medical Institute, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Hengameh Zahed
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine and Howard Hughes Medical Institute, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA; Medical Science Training Program, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Emin Maltepe
- Division of Neonatology, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | - David H Rowitch
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine and Howard Hughes Medical Institute, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA; Division of Neonatology, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA.
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69
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Miloudi K, Dejda A, Binet F, Lapalme E, Cerani A, Sapieha P. Assessment of vascular regeneration in the CNS using the mouse retina. J Vis Exp 2014:e51351. [PMID: 24998265 DOI: 10.3791/51351] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The rodent retina is perhaps the most accessible mammalian system in which to investigate neurovascular interplay within the central nervous system (CNS). It is increasingly being recognized that several neurodegenerative diseases such as Alzheimer's, multiple sclerosis, and amyotrophic lateral sclerosis present elements of vascular compromise. In addition, the most prominent causes of blindness in pediatric and working age populations (retinopathy of prematurity and diabetic retinopathy, respectively) are characterized by vascular degeneration and failure of physiological vascular regrowth. The aim of this technical paper is to provide a detailed protocol to study CNS vascular regeneration in the retina. The method can be employed to elucidate molecular mechanisms that lead to failure of vascular growth after ischemic injury. In addition, potential therapeutic modalities to accelerate and restore healthy vascular plexuses can be explored. Findings obtained using the described approach may provide therapeutic avenues for ischemic retinopathies such as that of diabetes or prematurity and possibly benefit other vascular disorders of the CNS.
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Affiliation(s)
| | - Agnieszka Dejda
- Department of Biochemistry, Maisonneuve-Rosemont Hospital Research Centre, University of Montréal
| | - François Binet
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, University of Montréal
| | - Eric Lapalme
- Department of Biochemistry, Maisonneuve-Rosemont Hospital Research Centre, University of Montréal
| | - Agustin Cerani
- Department of Biochemistry, Maisonneuve-Rosemont Hospital Research Centre, University of Montréal
| | - Przemyslaw Sapieha
- Department of Neurology-Neurosurgery, McGill University; Department of Biochemistry, Maisonneuve-Rosemont Hospital Research Centre, University of Montréal; Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, University of Montréal;
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Neonatal systemic inflammation in rats alters retinal vessel development and simulates pathologic features of retinopathy of prematurity. J Neuroinflammation 2014; 11:87. [PMID: 24886524 PMCID: PMC4030274 DOI: 10.1186/1742-2094-11-87] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 05/01/2014] [Indexed: 11/23/2022] Open
Abstract
Background Alteration of retinal angiogenesis during development leads to retinopathy of prematurity (ROP) in preterm infants, which is a leading cause of visual impairment in children. A number of clinical studies have reported higher rates of ROP in infants who had perinatal infections or inflammation, suggesting that exposure of the developing retina to inflammation may disturb retinal vessel development. Thus, we investigated the effects of systemic inflammation on retinal vessel development and retinal inflammation in neonatal rats. Methods To induce systemic inflammation, we intraperitoneally injected 100 μl lipopolysaccharide (LPS, 0.25 mg/ml) or the same volume of normal saline in rat pups on postnatal days 1, 3, and 5. The retinas were extracted on postnatal days 7 and 14, and subjected to assays for retinal vessels, inflammatory cells and molecules, and apoptosis. Results We found that intraperitoneal injection of LPS impaired retinal vessel development by decreasing vessel extension, reducing capillary density, and inducing localized overgrowth of abnormal retinal vessels and dilated peripheral vascular ridge, all of which are characteristic findings of ROP. Also, a large number of CD11c+ inflammatory cells and astrocytes were localized in the lesion of abnormal vessels. Further analysis revealed that the number of major histocompatibility complex (MHC) class IIloCD68loCD11bloCD11chi cells in the retina was higher in LPS-treated rats compared to controls. Similarly, the levels of TNF-α, IL-1β, and IL-12a were increased in LPS-treated retina. Also, apoptosis was increased in the inner retinal layer where retinal vessels are located. Conclusions Our data demonstrate that systemic LPS-induced inflammation elicits retinal inflammation and impairs retinal angiogenesis in neonatal rats, implicating perinatal inflammation in the pathogenesis of ROP.
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Michan S, Juan AM, Hurst CG, Cui Z, Evans LP, Hatton CJ, Pei DT, Ju M, Sinclair DA, Smith LEH, Chen J. Sirtuin1 over-expression does not impact retinal vascular and neuronal degeneration in a mouse model of oxygen-induced retinopathy. PLoS One 2014; 9:e85031. [PMID: 24416337 PMCID: PMC3885684 DOI: 10.1371/journal.pone.0085031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 11/20/2013] [Indexed: 12/28/2022] Open
Abstract
Proliferative retinopathy is a leading cause of blindness, including retinopathy of prematurity (ROP) in children and diabetic retinopathy in adults. Retinopathy is characterized by an initial phase of vessel loss, leading to tissue ischemia and hypoxia, followed by sight threatening pathologic neovascularization in the second phase. Previously we found that Sirtuin1 (Sirt1), a metabolically dependent protein deacetylase, regulates vascular regeneration in a mouse model of oxygen-induced proliferative retinopathy (OIR), as neuronal depletion of Sirt1 in retina worsens retinopathy. In this study we assessed whether over-expression of Sirtuin1 in retinal neurons and vessels achieved by crossing Sirt1 over-expressing flox mice with Nestin-Cre mice or Tie2-Cre mice, respectively, may protect against retinopathy. We found that over-expression of Sirt1 in Nestin expressing retinal neurons does not impact vaso-obliteration or pathologic neovascularization in OIR, nor does it influence neuronal degeneration in OIR. Similarly, increased expression of Sirt1 in Tie2 expressing vascular endothelial cells and monocytes/macrophages does not protect retinal vessels in OIR. In addition to the genetic approaches, dietary supplement with Sirt1 activators, resveratrol or SRT1720, were fed to wild type mice with OIR. Neither treatment showed significant vaso-protective effects in retinopathy. Together these results indicate that although endogenous Sirt1 is important as a stress-induced protector in retinopathy, over-expression of Sirt1 or treatment with small molecule activators at the examined doses do not provide additional protection against retinopathy in mice. Further studies are needed to examine in depth whether increasing levels of Sirt1 may serve as a potential therapeutic approach to treat or prevent retinopathy.
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Affiliation(s)
- Shaday Michan
- Instituto Nacional de Geriatría, Institutos Nacionales de Salud, México
| | - Aimee M Juan
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America ; Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Christian G Hurst
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Zhenghao Cui
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Lucy P Evans
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Colman J Hatton
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Dorothy T Pei
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Meihua Ju
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - David A Sinclair
- Paul F. Glenn Laboratories for the Biological Mechanisms of Aging, Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America ; Department of Pharmacology, The University of New South Wales, Kensington, Australia
| | - Lois E H Smith
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jing Chen
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America ; Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
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Neuron-derived semaphorin 3A is an early inducer of vascular permeability in diabetic retinopathy via neuropilin-1. Cell Metab 2013; 18:505-18. [PMID: 24093675 DOI: 10.1016/j.cmet.2013.09.003] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 07/20/2013] [Accepted: 08/23/2013] [Indexed: 01/01/2023]
Abstract
The deterioration of the inner blood-retinal barrier and consequent macular edema is a cardinal manifestation of diabetic retinopathy (DR) and the clinical feature most closely associated with loss of sight. We provide evidence from both human and animal studies for the critical role of the classical neuronal guidance cue, semaphorin 3A, in instigating pathological vascular permeability in diabetic retinas via its cognate receptor neuropilin-1. We reveal that semaphorin 3A is induced in early hyperglycemic phases of diabetes within the neuronal retina and precipitates initial breakdown of endothelial barrier function. We demonstrate, by a series of orthogonal approaches, that neutralization of semaphorin 3A efficiently prevents diabetes-induced retinal vascular leakage in a stage of the disease when vascular endothelial growth factor neutralization is inefficient. These observations were corroborated in Tg(Cre-Esr1)/Nrp1(flox/flox) conditional knockout mice. Our findings identify a therapeutic target for macular edema and provide further evidence for neurovascular crosstalk in the pathogenesis of DR.
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73
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Neuronal sirtuin1 mediates retinal vascular regeneration in oxygen-induced ischemic retinopathy. Angiogenesis 2013; 16:985-92. [PMID: 23912262 DOI: 10.1007/s10456-013-9374-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 07/24/2013] [Indexed: 10/26/2022]
Abstract
Regeneration of blood vessels in ischemic neuronal tissue is critical to reduce tissue damage in diseases. In proliferative retinopathy, initial vessel loss leads to retinal ischemia, which can induce either regrowth of vessels to restore normal metabolism and minimize damage, or progress to hypoxia-induced sight-threatening pathologic vaso-proliferation. It is not well understood how retinal neurons mediate regeneration of vascular growth in response to ischemic insults. In this study we aim to investigate the potential role of Sirtuin 1 (Sirt1), a metabolically-regulated protein deacetylase, in mediating the response of ischemic neurons to regulate vascular regrowth in a mouse model of oxygen-induced ischemic retinopathy (OIR). We found that Sirt1 is highly induced in the avascular ischemic retina in OIR. Conditional depletion of neuronal Sirt1 leads to significantly decreased retinal vascular regeneration into the avascular zone and increased hypoxia-induced pathologic vascular growth. This effect is likely independent of PGC-1α, a known Sirt1 target, as absence of PGC-1α in knockout mice does not impact vascular growth in retinopathy. We found that neuronal Sirt1 controls vascular regrowth in part through modulating deacetylation and stability of hypoxia-induced factor 1α and 2α, and thereby modulating expression of angiogenic factors. These results indicate that ischemic neurons induce Sirt1 to promote revascularization into ischemic neuronal areas, suggesting a novel role of neuronal Sirt1 in mediating vascular regeneration in ischemic conditions, with potential implications beyond retinopathy.
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Buehler A, Sitaras N, Favret S, Bucher F, Berger S, Pielen A, Joyal JS, Juan AM, Martin G, Schlunck G, Agostini HT, Klagsbrun M, Smith LEH, Sapieha P, Stahl A. Semaphorin 3F forms an anti-angiogenic barrier in outer retina. FEBS Lett 2013; 587:1650-5. [PMID: 23603393 DOI: 10.1016/j.febslet.2013.04.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/28/2013] [Accepted: 04/09/2013] [Indexed: 02/08/2023]
Abstract
Semaphorins are known modulators of axonal sprouting and angiogenesis. In the retina, we identified a distinct and almost exclusive expression of Semaphorin 3F in the outer layers. Interestingly, these outer retinal layers are physiologically avascular. Using functional in vitro models, we report potent anti-angiogenic effects of Semaphorin 3F on both retinal and choroidal vessels. In addition, human retinal pigment epithelium isolates from patients with pathologic neovascularization of the outer retina displayed reduced Semaphorin 3F expression in 10 out of 15 patients. Combined, these results elucidate a functional role for Semaphorin 3F in the outer retina where it acts as a vasorepulsive cue to maintain physiologic avascularity.
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75
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Binet F, Mawambo G, Sitaras N, Tetreault N, Lapalme E, Favret S, Cerani A, Leboeuf D, Tremblay S, Rezende F, Juan AM, Stahl A, Joyal JS, Milot E, Kaufman RJ, Guimond M, Kennedy TE, Sapieha P. Neuronal ER stress impedes myeloid-cell-induced vascular regeneration through IRE1α degradation of netrin-1. Cell Metab 2013; 17:353-71. [PMID: 23473031 DOI: 10.1016/j.cmet.2013.02.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 10/26/2012] [Accepted: 01/23/2013] [Indexed: 12/13/2022]
Abstract
In stroke and proliferative retinopathy, despite hypoxia driven angiogenesis, delayed revascularization of ischemic tissue aggravates the loss of neuronal function. What hinders vascular regrowth in the ischemic central nervous system remains largely unknown. Using the ischemic retina as a model of neurovascular interaction in the CNS, we provide evidence that the failure of reparative angiogenesis is temporally and spatially associated with endoplasmic reticulum (ER) stress. The canonical ER stress pathways of protein kinase RNA-like ER kinase (PERK) and inositol-requiring enzyme-1α (IRE1α) are activated within hypoxic/ischemic retinal ganglion neurons, initiating a cascade that results in angiostatic signals. Our findings demonstrate that the endoribonuclease IRE1α degrades the classical guidance cue netrin-1. This neuron-derived cue triggers a critical reparative-angiogenic switch in neural macrophage/microglial cells. Degradation of netrin-1, by persistent neuronal ER stress, thereby hinders vascular regeneration. These data identify a neuronal-immune mechanism that directly regulates reparative angiogenesis.
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Affiliation(s)
- François Binet
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, Montreal, QC H1T 2M4, Canada
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Javerzat S, Godard V, Bikfalvi A. Balancing risks and benefits of anti-angiogenic drugs for malignant glioma. FUTURE NEUROLOGY 2013. [DOI: 10.2217/fnl.12.91] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Angiogenesis is a delicate process that has been programmed over the time of evolution of vertebrates to provide optimized quantities of oxygen and nutrients to the developing embryo and the growing newborn. Similarly, angiogenesis induction pathways are used during tumor development. Angiogenesis and tumor cell invasion are closely linked. Anti-angiogenesis treatment strategies have entered the clinic and show some promising results. However, recent research using preclinical models have pointed to possible harmful effects, including evasive resistance and increase in tumor cell invasion when VEGF activity is inhibited. This has been corroborated by observations in treated glioblastoma patients. However, the meaning of these observations is still in question. The results of Phase III clinical trials that are ongoing will certainly provide more definitive answers with regard to evasive resistance in glioblastoma treated with anti-angiogenic drugs.
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Affiliation(s)
- Sophie Javerzat
- University of Bordeaux, Laboratoire de l’Angiogenèse et du Microenvironnement des Cancers, Unités Mixte de Recherche 1029, F-33400 Talence, France
- Institut National de la Santé et de la Recherche Médicale, Laboratoire de l’Angiogenèse et du Microenvironnement des Cancers, Unités Mixte de Recherche 1029, F-33400 Talence, France
| | - Virginie Godard
- University of Bordeaux, Laboratoire de l’Angiogenèse et du Microenvironnement des Cancers, Unités Mixte de Recherche 1029, F-33400 Talence, France
- Institut National de la Santé et de la Recherche Médicale, Laboratoire de l’Angiogenèse et du Microenvironnement des Cancers, Unités Mixte de Recherche 1029, F-33400 Talence, France
| | - Andreas Bikfalvi
- Institut National de la Santé et de la Recherche Médicale, Laboratoire de l’Angiogenèse et du Microenvironnement des Cancers, Unités Mixte de Recherche 1029, F-33400 Talence, France
- University of Bordeaux, Laboratoire de l’Angiogenèse et du Microenvironnement des Cancers, Unités Mixte de Recherche 1029, F-33400 Talence, France.
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