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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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2
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Chen ZY, Mao SF, Guo LH, Qin J, Yang LX, Liu Y. Effect of maternal pregestational diabetes mellitus on congenital heart diseases. World J Pediatr 2022; 19:303-314. [PMID: 35838899 DOI: 10.1007/s12519-022-00582-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/08/2022] [Indexed: 11/24/2022]
Abstract
BACKGROUND The increasing population of diabetes mellitus in adolescent girls and women of childbearing age contributes to a large number of pregnancies with maternal pregestational diabetes mellitus. Congenital heart diseases are a common adverse outcome in mothers with pregestational diabetes mellitus. However, there is little systematic information between maternal pregestational diabetes mellitus and congenital heart diseases in the offspring. DATA SOURCES Literature selection was performed in PubMed. One hundred and seven papers were cited in our review, including 36 clinical studies, 26 experimental studies, 31 reviews, eight meta-analysis articles, and six of other types. RESULTS Maternal pregestational diabetes mellitus poses a high risk of congenital heart diseases in the offspring and causes variety of phenotypes of congenital heart diseases. Factors such as persistent maternal hyperglycemia, oxidative stress, polymorphism of uncoupling protein 2, polymorphism of adiponectin gene, Notch 1 pathway, Nkx2.5 disorders, dysregulation of the hypoxia-inducible factor 1, and viral etiologies are associated with the occurrence of congenital heart diseases in the offspring of mothers with pregestational diabetes mellitus. Treatment options including blood sugar-reducing, anti-oxidative stress drug supplements and exercise can help to prevent maternal pregestational diabetes mellitus from inducing congenital heart diseases. CONCLUSIONS Our review contributes to a better understanding of the association between maternal pregestational diabetes mellitus and congenital heart diseases in the offspring and to a profound thought of the mechanism, preventive and therapeutic measurements of congenital heart diseases caused by maternal pregestational diabetes mellitus.
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Affiliation(s)
- Zhi-Yan Chen
- Department of Basic Medical Sciences, Sichuan Vocational College of Health and Rehabilitation, Zigong, 643000, China
| | - Shuang-Fa Mao
- Department of Basic Medical Sciences, Sichuan Vocational College of Health and Rehabilitation, Zigong, 643000, China
| | - Ling-Hong Guo
- Department of Pharmacology, West China School of Basic Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Jian Qin
- Department of Basic Medical Sciences, Sichuan Vocational College of Health and Rehabilitation, Zigong, 643000, China
| | - Li-Xin Yang
- Department of Basic Medical Sciences, Sichuan Vocational College of Health and Rehabilitation, Zigong, 643000, China
| | - Yin Liu
- Department of Basic Medical Sciences, Sichuan Vocational College of Health and Rehabilitation, Zigong, 643000, China. .,Department of Pharmacology, West China School of Basic Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China. .,Department of Anesthesiology, Sichuan Cancer Hospital and Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610000, China. .,Animal Research Institute, Sichuan University, Chengdu, China.
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3
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Smith TL, Oubaha M, Cagnone G, Boscher C, Kim JS, El Bakkouri Y, Zhang Y, Chidiac R, Corriveau J, Delisle C, Andelfinger GU, Sapieha P, Joyal JS, Gratton JP. eNOS controls angiogenic sprouting and retinal neovascularization through the regulation of endothelial cell polarity. Cell Mol Life Sci 2021; 79:37. [PMID: 34971428 PMCID: PMC8739159 DOI: 10.1007/s00018-021-04042-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 10/27/2021] [Accepted: 11/13/2021] [Indexed: 11/29/2022]
Abstract
The roles of nitric oxide (NO) and endothelial NO synthase (eNOS) in the regulation of angiogenesis are well documented. However, the involvement of eNOS in the sprouting of endothelial tip-cells at the vascular front during sprouting angiogenesis remains poorly defined. In this study, we show that downregulation of eNOS markedly inhibits VEGF-stimulated migration of endothelial cells but increases their polarization, as evidenced by the reorientation of the Golgi in migrating monolayers and by the fewer filopodia on tip cells at ends of sprouts in endothelial cell spheroids. The effect of eNOS inhibition on EC polarization was prevented in Par3-depleted cells. Importantly, downregulation of eNOS increased the expression of polarity genes, such as PARD3B, PARD6A, PARD6B, PKCΖ, TJP3, and CRB1 in endothelial cells. In retinas of eNOS knockout mice, vascular development is retarded with decreased vessel density and vascular branching. Furthermore, tip cells at the extremities of the vascular front have a marked reduction in the number of filopodia per cell and are more oriented. In a model of oxygen-induced retinopathy (OIR), eNOS deficient mice are protected during the initial vaso-obliterative phase, have reduced pathological neovascularization, and retinal endothelial tip cells have fewer filopodia. Single-cell RNA sequencing of endothelial cells from OIR retinas revealed enrichment of genes related to cell polarity in the endothelial tip-cell subtype of eNOS deficient mice. These results indicate that inhibition of eNOS alters the polarity program of endothelial cells, which increases cell polarization, regulates sprouting angiogenesis and normalizes pathological neovascularization during retinopathy.
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Affiliation(s)
- Tracy L Smith
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Malika Oubaha
- Département des Sciences Biologiques, Université du Québec à Montréal (UQAM), Montreal, QC, Canada.
| | - Gael Cagnone
- Department of Pediatrics and Centre Hospitalier Universitaire Ste-Justine, Université de Montréal, Montreal, QC, Canada
| | - Cécile Boscher
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Jin Sung Kim
- Department of Pediatrics and Centre Hospitalier Universitaire Ste-Justine, Université de Montréal, Montreal, QC, Canada
| | - Yassine El Bakkouri
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Ying Zhang
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Rony Chidiac
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
- Donnelly Centre, University of Toronto, Toronto, Canada
| | - Jeanne Corriveau
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Chantal Delisle
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Gregor U Andelfinger
- Department of Pediatrics and Centre Hospitalier Universitaire Ste-Justine, Université de Montréal, Montreal, QC, Canada
| | - Przemyslaw Sapieha
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, Université de Montréal, Montreal, QC, Canada
| | - Jean-Sébastien Joyal
- Department of Pediatrics and Centre Hospitalier Universitaire Ste-Justine, Université de Montréal, Montreal, QC, Canada
| | - Jean-Philippe Gratton
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada.
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4
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Ninchoji T, Love DT, Smith RO, Hedlund M, Vestweber D, Sessa WC, Claesson-Welsh L. eNOS-induced vascular barrier disruption in retinopathy by c-Src activation and tyrosine phosphorylation of VE-cadherin. eLife 2021; 10:64944. [PMID: 33908348 PMCID: PMC8087444 DOI: 10.7554/elife.64944] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 04/22/2021] [Indexed: 12/30/2022] Open
Abstract
Background: Hypoxia and consequent production of vascular endothelial growth factor A (VEGFA) promote blood vessel leakiness and edema in ocular diseases. Anti-VEGFA therapeutics may aggravate hypoxia; therefore, therapy development is needed. Methods: Oxygen-induced retinopathy was used as a model to test the role of nitric oxide (NO) in pathological neovascularization and vessel permeability. Suppression of NO formation was achieved chemically using L-NMMA, or genetically, in endothelial NO synthase serine to alanine (S1176A) mutant mice. Results: Suppression of NO formation resulted in reduced retinal neoangiogenesis. Remaining vascular tufts exhibited reduced vascular leakage through stabilized endothelial adherens junctions, manifested as reduced phosphorylation of vascular endothelial (VE)-cadherin Y685 in a c-Src-dependent manner. Treatment with a single dose of L-NMMA in established retinopathy restored the vascular barrier and prevented leakage. Conclusions: We conclude that NO destabilizes adheren junctions, resulting in vascular hyperpermeability, by converging with the VEGFA/VEGFR2/c-Src/VE-cadherin pathway. Funding: This study was supported by the Swedish Cancer foundation (19 0119 Pj ), the Swedish Research Council (2020-01349), the Knut and Alice Wallenberg foundation (KAW 2020.0057) and a Fondation Leducq Transatlantic Network of Excellence Grant in Neurovascular Disease (17 CVD 03). KAW also supported LCW with a Wallenberg Scholar grant (2015.0275). WCS was supported by Grants R35 HL139945, P01 HL1070205, AHA MERIT Award. DV was supported by grants from the Deutsche Forschungsgemeinschaft, SFB1450, B03, and CRU342, P2.
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Affiliation(s)
- Takeshi Ninchoji
- Uppsala University, Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala, Sweden
| | - Dominic T Love
- Uppsala University, Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala, Sweden
| | - Ross O Smith
- Uppsala University, Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala, Sweden
| | - Marie Hedlund
- Uppsala University, Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala, Sweden
| | | | - William C Sessa
- Yale University School of Medicine, Department of Pharmacology and Vascular Biology and Therapeutics Program, New Haven, United States
| | - Lena Claesson-Welsh
- Uppsala University, Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala, Sweden
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5
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Nishimura K, Nie M, Miura S, Takeuchi S. Microfluidic Device for the Analysis of Angiogenic Sprouting under Bidirectional Biochemical Gradients. MICROMACHINES 2020; 11:E1049. [PMID: 33261134 PMCID: PMC7761305 DOI: 10.3390/mi11121049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 11/25/2020] [Accepted: 11/26/2020] [Indexed: 12/04/2022]
Abstract
In this paper, we developed a spheroid culture device that can trap a spheroid in the trapping site sandwiched by two extracellular matrix gels located at the upper and lower side of the spheroid. This device can form different biochemical gradients by applying target biochemicals separately in upper and lower channels, allowing us to study the angiogenic sprouting under various biochemical gradients in different directions. In the experiments, we confirmed the trapping of the spheroids and demonstrate the investigation on the direction and extent of angiogenic sprouts under unidirectional or bidirectional biochemical gradients. We believe our device can contribute to understanding the pathophysiological phenomena driven by chemical gradients, such as tissue development and tumor angiogenesis.
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Affiliation(s)
- Keigo Nishimura
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan;
| | - Minghao Nie
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan;
| | - Shigenori Miura
- Institute of Industrial Science (IIS), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan;
| | - Shoji Takeuchi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan;
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan;
- Institute of Industrial Science (IIS), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan;
- International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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6
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PPAR- γ Mediates Ta-VNS-Induced Angiogenesis and Subsequent Functional Recovery after Experimental Stroke in Rats. BIOMED RESEARCH INTERNATIONAL 2020; 2020:8163789. [PMID: 32775443 PMCID: PMC7396041 DOI: 10.1155/2020/8163789] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/09/2020] [Accepted: 06/18/2020] [Indexed: 02/05/2023]
Abstract
Background Neoangiogenesis after cerebral ischemia in mammals is insufficient to restore neurological function, illustrating the need to design better strategies for improving outcomes. Our previous study has suggested that transcutaneous auricular vagus nerve stimulation (ta-VNS) induced angiogenesis and improved neurological functions in a rat model of cerebral ischemia/reperfusion (I/R) injury. However, the mechanisms involved need further exploration. Peroxisome proliferator-activated receptor-γ (PPAR-γ), well known as a ligand-modulated nuclear transcription factor, plays a crucial role in the regulation of cerebrovascular structure and function. Hence, the present study was designed to explore the role of PPAR-γ in ta-VNS-mediated angiogenesis and uncover the possible molecular mechanisms against ischemic stroke. Methods Adult male Sprague-Dawley rats were transfected with either PPAR-γ small interfering RNA (siRNA) or lentiviral vector without siRNA prior to surgery and subsequently received ta-VNS treatment. The expression and localization of PPAR-γ in the ischemic boundary after ta-VNS treatment were examined. Subsequently, neurological deficit scores, neuronal damage, and infarct volume were all evaluated. Additionally, microvessel density, endothelial cell proliferation condition, and the expression of angiogenesis-related molecules in the peri-infarct cortex were measured. Results We found that the expression of PPAR-γ in the peri-infarct cortex increased at 14 d and reached normal levels at 28 d after reperfusion. Ta-VNS treatment further upregulated PPAR-γ expression in the ischemic cortex. PPAR-γ was mainly expressed in neurons and astrocytes. Furthermore, ta-VNS-treated I/R rats showed better neurobehavioral recovery, alleviated neuronal injury, reduced infarct volume, and increased angiogenesis, as indicated by the elevated levels of brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), and phosphorylated endothelial nitric oxide synthase (P-eNOS). Surprisingly, the beneficial effects of ta-VNS were weakened after PPAR-γ silencing. Conclusions Our results suggest that PPAR-γ is a potential mediator of ta-VNS-induced angiogenesis and neuroprotection against cerebral I/R injury.
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7
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Gericke A, Wolff I, Musayeva A, Zadeh JK, Manicam C, Pfeiffer N, Li H, Xia N. Retinal arteriole reactivity in mice lacking the endothelial nitric oxide synthase (eNOS) gene. Exp Eye Res 2019; 181:150-156. [PMID: 30716330 DOI: 10.1016/j.exer.2019.01.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/17/2019] [Accepted: 01/31/2019] [Indexed: 12/20/2022]
Abstract
Dysfunctional vascular endothelial nitric oxide synthase (eNOS) has been proposed to play a main pathophysiological role in various ocular diseases. The aim of the present study was to test the hypothesis that the chronic lack of eNOS impairs endothelium-dependent vasodilation in retinal arterioles. The relevance of eNOS for mediating vascular responses was studied in retinal vascular preparations from eNOS-deficient mice (eNOS-/-) and wild-type controls in vitro. Changes in luminal diameter in response to vasoactive agents were measured by videomicroscopy. The thromboxane mimetic, U46619, induced similar concentration-dependent constriction of retinal arterioles in eNOS-/- and wild-type mice. Responses to the endothelium-independent vasodilator, nitroprusside, did not differ between both mouse genotypes, either. In contrast, responses to the endothelium-dependent vasodilator, acetylcholine, were blunted in eNOS-/- mice. Non-isoform-selective blockade of either nitric oxide synthase (NOS) or cyclooxygenase (COX) alone did not affect responses to acetylcholine. However, combined blockade of both enzyme families markedly attenuated cholinergic vasodilation. Also, combined blockade of COX and neuronal NOS (nNOS) blunted acetylcholine-induced vasodilation, while combined COX and inducible NOS (iNOS) inhibition had no effect. Simultaneous NOS and COX-1 blockade did not affect cholinergic vasodilation, whereas combined NOS and COX-2 inhibition markedly reduced vasodilation to acetylcholine. These findings are the first to demonstrate that the chronic lack of eNOS is associated with moderate endothelial dysfunction in retinal arterioles. However, eNOS-deficiency is partially compensated by nNOS and COX-2 metabolites, which are reciprocally regulated.
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Affiliation(s)
- Adrian Gericke
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstr. 1, 55131, Mainz, Germany.
| | - Ismael Wolff
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstr. 1, 55131, Mainz, Germany
| | - Aytan Musayeva
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstr. 1, 55131, Mainz, Germany
| | - Jenia Kouchek Zadeh
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstr. 1, 55131, Mainz, Germany
| | - Caroline Manicam
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstr. 1, 55131, Mainz, Germany
| | - Norbert Pfeiffer
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstr. 1, 55131, Mainz, Germany
| | - Huige Li
- Department of Pharmacology, University Medical Center, Johannes Gutenberg University Mainz, Obere Zahlbacher Str. 67, 55131, Mainz, Germany
| | - Ning Xia
- Department of Pharmacology, University Medical Center, Johannes Gutenberg University Mainz, Obere Zahlbacher Str. 67, 55131, Mainz, Germany
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Zhou R, Zhang S, Gu X, Ge Y, Zhong D, Zhou Y, Tang L, Liu XL, Chen JF. Adenosine A 2A receptor antagonists act at the hyperoxic phase to confer protection against retinopathy. Mol Med 2018; 24:41. [PMID: 30134834 PMCID: PMC6069809 DOI: 10.1186/s10020-018-0038-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 07/16/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Retinopathy of prematurity (ROP) remains a major cause of childhood blindness and current laser photocoagulation and anti-VEGF antibody treatments are associated with reduced peripheral vision and possible delayed development of retinal vasculatures and neurons. In this study, we advanced the translational potential of adenosine A2A receptor (A2AR) antagonists as a novel therapeutic strategy for selectively controlling pathological retinal neovascularization in oxygen-induced retinopathy (OIR) model of ROP. METHODS Developing C57BL/6 mice were exposed to 75% oxygen from postnatal (P) day 7 to P12 and to room air from P12 to P17 and treated with KW6002 or vehicle at different postnatal developmental stages. Retinal vascularization was examined by whole-mount fluorescence and cross-sectional hematoxylin-eosin staining. Cellular proliferation, astrocyte and microglial activation, and tip cell function were investigated by isolectin staining and immunohistochemistry. Apoptosis was analyzed by TUNEL assay. The effects of oxygen exposure and KW6002 treatment were analyzed by two-way ANOVA or Kruskal-Wallis test or independent Student's t-test or Mann-Whitney U test. RESULTS The A2AR antagonist KW6002 (P7-P17) did not affect normal postnatal development of retinal vasculature, but selectively reduced avascular areas and neovascularization, with the reduced cellular apoptosis and proliferation, and enhanced astrocyte and tip cell functions in OIR. Importantly, contrary to our prediction that A2AR antagonists were most effective at the hypoxic phase with aberrantly increased adenosine-A2AR signaling, we discovered that the A2AR antagonist KW6002 mainly acted at the hyperoxic phase to confer protection against OIR as KW6002 treatment at P7-P12 (but not P12-P17) conferred protection against OIR; this protection was observed as early as P9 with reduced avascular areas and reduced cellular apoptosis and reversal of eNOS mRNA down-regulation in retina of OIR. CONCLUSIONS As ROP being a biphasic disease, our identification of the hyperoxic phase as the effective window, together with selective and robust protection against pathological (but not physiological) angiogenesis, elevates A2AR antagonists as a novel therapeutic strategy for ROP treatment.
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Affiliation(s)
- Rong Zhou
- Institute of Molecular Medicine, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, 270 Xueyuan Road, Wenzhou, 325027, Zhejiang, China.,State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Shuya Zhang
- Institute of Molecular Medicine, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, 270 Xueyuan Road, Wenzhou, 325027, Zhejiang, China.,State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Xuejiao Gu
- Institute of Molecular Medicine, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, 270 Xueyuan Road, Wenzhou, 325027, Zhejiang, China.,State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Yuanyuan Ge
- Institute of Molecular Medicine, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, 270 Xueyuan Road, Wenzhou, 325027, Zhejiang, China.,State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Dingjuan Zhong
- Institute of Molecular Medicine, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, 270 Xueyuan Road, Wenzhou, 325027, Zhejiang, China.,State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Yuling Zhou
- Institute of Molecular Medicine, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, 270 Xueyuan Road, Wenzhou, 325027, Zhejiang, China.,State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Lingyun Tang
- Institute of Molecular Medicine, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, 270 Xueyuan Road, Wenzhou, 325027, Zhejiang, China.,State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Xiao-Ling Liu
- Institute of Molecular Medicine, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, 270 Xueyuan Road, Wenzhou, 325027, Zhejiang, China. .,State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China.
| | - Jiang-Fan Chen
- Institute of Molecular Medicine, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, 270 Xueyuan Road, Wenzhou, 325027, Zhejiang, China. .,State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China.
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9
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Opatrilova R, Kubatka P, Caprnda M, Büsselberg D, Krasnik V, Vesely P, Saxena S, Ruia S, Mozos I, Rodrigo L, Kruzliak P, dos Santos KG. Nitric oxide in the pathophysiology of retinopathy: evidences from preclinical and clinical researches. Acta Ophthalmol 2018; 96:222-231. [PMID: 28391624 DOI: 10.1111/aos.13384] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 12/12/2016] [Indexed: 12/11/2022]
Abstract
Retinopathy is the leading cause of blindness and visual disability in working-aged people. The pathogenesis of retinopathy is an actual and still open query. Alterations contributing to oxidative and nitrosative stress, including elevated nitric oxide and superoxide production, changes in the expression of different isoforms of nitric oxide synthase or endogenous antioxidant system, have been implicated in the mechanisms how this ocular disease develops. In addition, it was documented that renin-angiotensin system has been implicated in the progression of retinopathy. Based on comprehensive preclinical and clinical researches in this area, the role of above-mentioned factors in the pathogenesis of diabetic retinopathy, hypertensive retinopathy and ischaemic proliferative retinopathy is reviewed in this study. Moreover, the genetic susceptibility factors involved in the development of the retinopathy and possible strategies that utilize antioxidants as additive therapy are also highlighted here.
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Affiliation(s)
- Radka Opatrilova
- Department of Chemical Drugs; Faculty of Pharmacy; University of Veterinary and Pharmaceutical Sciences; Brno Czech Republic
| | - Peter Kubatka
- Department of Medical Biology; Jessenius Faculty of Medicine; Comenius University in Bratislava; Martin Slovak Republic
- Division of Oncology; Biomedical Center Martin; Jessenius Faculty of Medicine; Comenius University in Bratislava; Martin Slovak Republic
| | - Martin Caprnda
- 2nd Department of Internal Medicine; Faculty of Pharmacy; Comenius University; Bratislava Slovakia
| | | | - Vladimir Krasnik
- Department of Ophthalmology; Faculty of Medicine; Comenius University; Bratislava Slovakia
| | | | - Sandeep Saxena
- Retina Service; Department of Ophthalmology; King George's Medical University; Lucknow India
| | - Surabhi Ruia
- Retina Service; Department of Ophthalmology; King George's Medical University; Lucknow India
| | - Ioana Mozos
- Department of Functional Sciences; “Victor Babes” University of Medicine and Pharmacy; Timisoara Romania
| | - Luis Rodrigo
- Faculty of Medicine; University of Oviedo; Central University Hospital of Asturias (HUCA); Oviedo Spain
| | - Peter Kruzliak
- Department of Chemical Drugs; Faculty of Pharmacy; University of Veterinary and Pharmaceutical Sciences; Brno Czech Republic
| | - Katia Goncalves dos Santos
- Laboratory of Human Molecular Genetics; Universidade Luterana do Brasil; Canoas Brazil
- Experimental and Molecular Cardiovascular Laboratory; Hospital de Clínicas de Porto Alegre; Porto Alegre Brazil
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10
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Rivera JC, Noueihed B, Madaan A, Lahaie I, Pan J, Belik J, Chemtob S. Tetrahydrobiopterin (BH4) deficiency is associated with augmented inflammation and microvascular degeneration in the retina. J Neuroinflammation 2017; 14:181. [PMID: 28874201 PMCID: PMC5586016 DOI: 10.1186/s12974-017-0955-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 08/28/2017] [Indexed: 02/07/2023] Open
Abstract
Background Tetrahydrobiopterin (BH4) is an essential cofactor in multiple metabolic processes and plays an essential role in maintaining the inflammatory and neurovascular homeostasis. In this study, we have investigated the deleterious effects of BH4 deficiency on retinal vasculature during development. Methods hph-1 mice, which display deficiency in BH4 synthesis, were used to characterize the inflammatory effects and the integrity of retinal microvasculature. BH4 levels in retinas from hph-1 and wild type (WT) mice were measured by LC-MS/MS. Retinal microvascular area and microglial cells number were quantified in hph-1 and WT mice at different ages. Retinal expression of pro-inflammatory, anti-angiogenic, and neuronal-derived factors was analyzed by qPCR. BH4 supplementation was evaluated in vitro, ex-vivo, and in vivo models. Results Our findings demonstrated that BH4 levels in the retina from hph-1 mice were significantly lower by ~ 90% at all ages analyzed compared to WT mice. Juvenile hph-1 mice showed iris atrophy, persistent fetal vasculature, significant increase in the number of microglial cells (p < 0.01), as well as a marked degeneration of the retinal microvasculature. Retinal microvascular alterations in juvenile hph-1 mice were associated with a decreased expression in Norrin (0.2-fold) and its receptor Frizzled-4 (FZD4; 0.51-fold), as well as with an augmented expression of pro-inflammatory factors such as IL-6 (3.2-fold), NRLP-3 (4.4-fold), IL-1β (8.6-fold), and the anti-angiogenic factor thrombospondin-1 (TSP-1; 17.5-fold). We found that TSP-1 derived from activated microglial cells is a factor responsible of inducing microvascular degeneration, but BH4 supplementation markedly prevented hyperoxia-induced microglial activation in vitro and microvascular injury in an ex-vivo model of microvascular angiogenesis and an in vivo model of oxygen-induced retinopathy (OIR). Conclusion Our findings reveal that BH4 is a key cofactor in regulating the expression of inflammatory and anti-angiogenic factors that play an important function in the maintenance of retinal microvasculature. Electronic supplementary material The online version of this article (10.1186/s12974-017-0955-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- José Carlos Rivera
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Center, Université de Montréal, 5415 Blvd de l'Assomption, Montréal, Québec, H1T 2M4, Canada. .,Department of Pediatrics, Ophthalmology and Pharmacology, CHU Sainte-Justine Research Center, Université de Montréal, Montréal, QC, Canada.
| | - Baraa Noueihed
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Center, Université de Montréal, 5415 Blvd de l'Assomption, Montréal, Québec, H1T 2M4, Canada
| | - Ankush Madaan
- Department of Pediatrics, Ophthalmology and Pharmacology, CHU Sainte-Justine Research Center, Université de Montréal, Montréal, QC, Canada
| | - Isabelle Lahaie
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Center, Université de Montréal, 5415 Blvd de l'Assomption, Montréal, Québec, H1T 2M4, Canada
| | - Jingyi Pan
- Departments of Pediatrics and Physiology, The Hospital For Sick Children, University of Toronto, Toronto, Canada
| | - Jaques Belik
- Departments of Pediatrics and Physiology, The Hospital For Sick Children, University of Toronto, Toronto, Canada
| | - Sylvain Chemtob
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Center, Université de Montréal, 5415 Blvd de l'Assomption, Montréal, Québec, H1T 2M4, Canada. .,Department of Pediatrics, Ophthalmology and Pharmacology, CHU Sainte-Justine Research Center, Université de Montréal, Montréal, QC, Canada.
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11
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Edgar KS, Galvin OM, Collins A, Katusic ZS, McDonald DM. BH4-Mediated Enhancement of Endothelial Nitric Oxide Synthase Activity Reduces Hyperoxia-Induced Endothelial Damage and Preserves Vascular Integrity in the Neonate. Invest Ophthalmol Vis Sci 2017; 58:230-241. [PMID: 28114584 PMCID: PMC6039076 DOI: 10.1167/iovs.16-20523] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Accepted: 11/06/2016] [Indexed: 01/11/2023] Open
Abstract
Purpose Endothelial nitric oxide synthase (eNOS)-derived nitric oxide (NO) has important vasoprotective functions that are compromised in the vasodegenerative phase of retinopathy of prematurity, owing to hyperoxia-induced depletion of the essential NOS cofactor BH4. Because modulating eNOS function can be beneficial or detrimental, our aim was to investigate the effect of BH4 supplementation on eNOS function and vascular regression in hyperoxia. Methods Endothelial-specific eNOS-green fluorescent protein (GFP) overexpressing mice at postnatal day 7 (P7) were exposed to hyperoxia for 48 hours in the presence or absence of supplemental BH4, achieved by administration of sepiapterin, a stable BH4 precursor. Tissue was collected either for retinal flat mounts that were stained with lectin to determine the extent of vessel coverage or for analysis of BH4 by high-performance liquid chromatography, nitrotyrosine (NT) marker by Western blotting, VEGF expression by ELISA, and NOS activity by arginine-to-citrulline conversion. Primary retinal microvascular endothelial cells (RMEC) were similarly treated, and hyperoxia-induced damage was determined. Results Sepiapterin effectively enhanced BH4 levels in hyperoxia-exposed retinas and brains, elevated NOS activity, and reduced NT-modified protein, leading to reversal of the exacerbated vasoregression observed in the presence of eNOS overexpression. In RMECs, hyperoxia-mediated depletion of BH4 dysregulated the redox balance by reducing nitrite and elevating superoxide and impaired proliferative ability. BH4 supplementation restored normal RMEC proliferation in vitro and also in vivo, providing a mechanistic link with the enhanced vascular coverage in eNOS-GFP retinas. Conclusions These results demonstrate that BH4 supplementation corrects hyperoxia-induced RMEC dysfunction and preserves vascular integrity by enhancing eNOS function.
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Affiliation(s)
- Kevin S. Edgar
- Centre for Experimental Medicine, Queen's University Belfast, United Kingdom
| | - Orla M. Galvin
- Centre for Experimental Medicine, Queen's University Belfast, United Kingdom
| | - Anthony Collins
- Centre for Experimental Medicine, Queen's University Belfast, United Kingdom
| | - Zvonimir S. Katusic
- Department of Anesthesiology and Pharmacology, Mayo Clinic, Minnesota, United States
| | - Denise M. McDonald
- Centre for Experimental Medicine, Queen's University Belfast, United Kingdom
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12
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Edgar KS, Matesanz N, Gardiner TA, Katusic ZS, McDonald DM. Hyperoxia depletes (6R)-5,6,7,8-tetrahydrobiopterin levels in the neonatal retina: implications for nitric oxide synthase function in retinopathy. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:1769-82. [PMID: 25913075 DOI: 10.1016/j.ajpath.2015.02.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 01/20/2015] [Accepted: 02/10/2015] [Indexed: 02/08/2023]
Abstract
Retinopathy of prematurity is a sight-threatening complication of premature birth caused by nitro-oxidative insult to the developing retinal vasculature during therapeutic hyperoxia exposure and later ischemia-induced neovascularization on supplemental oxygen withdrawal. In the vasodegenerative phase, during hyperoxia, defective endothelial nitric oxide synthase (NOS) produces reactive oxygen and nitrogen free radicals rather than vasoprotective nitric oxide for unclear reasons. Crucially, normal NOS function depends on availability of the cofactor (6R)-5,6,7,8-tetrahydrobiopterin (BH4). Because BH4 synthesis is controlled enzymatically by GTP cyclohydrolase (GTPCH), we used GTPCH-depleted mice [hyperphenylalaninemia strain (hph1)] to investigate the impact of hyperoxia on BH4 bioavailability and retinal vascular pathology in the neonate. Hyperoxia decreased BH4 in retinas, lungs, and aortas in all experimental groups, resulting in a dose-dependent decrease in NOS activity and, in the wild-type group, elevated NOS-derived superoxide. Retinal dopamine levels were similarly diminished, consistent with the dependence of tyrosine hydroxylase on BH4. Despite greater depletion of BH4, the hph(+/-) and hph1(-/-) groups did not show exacerbated hyperoxia-induced vessel closure, but exhibited greater vascular protection and reduced progression to neovascular disease. This vasoprotective effect was independent of enhanced circulating vascular endothelial growth factor (VEGF), which was reduced by hyperoxia, but to local retinal ganglion cell layer-derived VEGF. In conclusion, a constitutively higher level of VEGF expression associated with retinal development protects GTPCH-deficient neonates from oxygen-induced vascular damage.
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Affiliation(s)
- Kevin S Edgar
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Nuria Matesanz
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Tom A Gardiner
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Zvonimir S Katusic
- Department of Pharmacology and Anesthesiology, Mayo Clinic, Rochester, Minnesota
| | - Denise M McDonald
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom.
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13
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Zhang Q, Jiang Y, Steinle JJ. IGFBP-3 reduces eNOS and PKCzeta phosphorylation, leading to lowered VEGF levels. Mol Vis 2015; 21:604-11. [PMID: 26015772 PMCID: PMC4443585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 05/20/2015] [Indexed: 10/25/2022] Open
Abstract
PURPOSE In models of diabetic retinopathy, insulin-like growth factor binding protein-3 (IGFBP-3) is protective to the retina, especially retinal microvascular endothelial cells (RECs), but the underlying mechanisms are unclear. For this study, we hypothesized that IGFBP-3 may reduce vascular endothelial growth factor (VEGF) levels through reduced endothelial nitric oxide synthase (eNOS) activity, which may be protective against macular edema. METHODS To test this hypothesis, we grew primary human retinal endothelial cells in normal glucose (5 mM) or high glucose (25 mM) for three days, treated with IGFBP-3 NB plasmid (a plasmid of IGFBP-3 that cannot bind IGF-1), followed by western blotting for eNOS, protein kinase C zeta (PKCzeta), and VEGF. Additionally, we treated some cells with recombinant eNOS or PKCzeta, after IGFBP-3 NB plasmid transfection to validate that these pathways regulate VEGF levels. Immunoprecipitation experiments were done with the eNOS antibody, followed by western blotting for PKCzeta, to determine if eNOS and PKCzeta interact directly. RESULTS Our results suggest that 1) IGFBP-3 inhibits the endothelial nitric oxide synthase (eNOS) and protein kinase C zeta (PKCzeta) pathway, which in turn inhibits VEGF production, and 2) that eNOS plays a role in activating PKCzeta to increase VEGF levels in diabetic retinopathy. CONCLUSIONS In conclusion, IGFBP-3 may be a novel treatment for macular edema through the inhibition of eNOS and PKCzeta activation, leading to reduced VEGF levels.
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Affiliation(s)
- Qiuhua Zhang
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN
| | - Youde Jiang
- Department of Anatomy and Cell Biology, Wayne State University, Detroit, MI
| | - Jena J. Steinle
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN,Department of Anatomy and Cell Biology, Wayne State University, Detroit, MI,Department of Ophthalmology, Wayne State University, Detroit, MI
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14
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Okaniwa N, Sasaki M, Mizushima T, Ogasawara N, Funaki Y, Joh T, Kasugai K. eNOS plays an important role in the regulation of colonic inflammation: a novel therapeutic target and a predictive marker for the prognosis of ulcerative colitis. Free Radic Res 2014; 49:35-44. [PMID: 25329334 DOI: 10.3109/10715762.2014.977788] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND We reported that deficiency of the eNOS protein exacerbates colitis induced by dextran sodium sulfate (DSS-induced colitis). However, the role of eNOS in colitis remains controversial. Therefore, we studied how over-expression of eNOS affected this inflammatory condition, using vascular endothelial cells and mice as in vitro and in vivo models, respectively. Furthermore, we investigated the influence of a polymorphism in the eNOS gene on the clinical features of ulcerative colitis (UC). METHODS We examined the effect of eNOS overexpression on the expression of adhesion molecules in the endothelium and assessed the degree of DSS-induced colitis in eNOS transgenic (eNOS-Tg) mice. We also investigated the relationship between a polymorphism in the eNOS gene and clinical features of patients with UC. RESULTS The expression of adhesion molecules, under inflammatory conditions, was attenuated in eNOS gene-transfected vascular endothelial cells, as measured by western blot analysis. Symptoms of DSS-induced colitis were likewise attenuated in eNOS-Tg mice, which exhibited lower weight loss, mortality, histological damage (by inflammation score and crypt damage score), and colonic myeloperoxidase activity, tumor necrosis factor-α expression, and MAdCAM-1 expression than in wild-type mice. Furthermore, there was a significant relationship between intractable cases of UC and a polymorphism in the eNOS gene promoter (c.-786 T > C) that decreases eNOS expression. CONCLUSION The eNOS gene plays an important role in the regulation of colonic inflammation. The level of eNOS expression may be a predictive marker for prognosis of UC, and eNOS expression may be a novel therapeutic target.
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Affiliation(s)
- N Okaniwa
- Department of Gastroenterology, Aichi Medical University School of Medicine , Nagakute , Japan
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Suwanpradid J, Rojas M, Behzadian MA, Caldwell RW, Caldwell RB. Arginase 2 deficiency prevents oxidative stress and limits hyperoxia-induced retinal vascular degeneration. PLoS One 2014; 9:e110604. [PMID: 25375125 PMCID: PMC4222858 DOI: 10.1371/journal.pone.0110604] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 09/16/2014] [Indexed: 01/02/2023] Open
Abstract
Background Hyperoxia exposure of premature infants causes obliteration of the immature retinal microvessels, leading to a condition of proliferative vitreoretinal neovascularization termed retinopathy of prematurity (ROP). Previous work has demonstrated that the hyperoxia-induced vascular injury is mediated by dysfunction of endothelial nitric oxide synthase resulting in peroxynitrite formation. This study was undertaken to determine the involvement of the ureahydrolase enzyme arginase in this pathology. Methods and Findings Studies were performed using hyperoxia-treated bovine retinal endothelial cells (BRE) and mice with oxygen-induced retinopathy (OIR) as experimental models of ROP. Treatment with the specific arginase inhibitor 2(S)-amino-6-boronohexanoic acid (ABH) prevented hyperoxia-induced apoptosis of BRE cells and reduced vaso-obliteration in the OIR model. Furthermore, deletion of the arginase 2 gene protected against hyperoxia-induced vaso-obliteration, enhanced physiological vascular repair, and reduced retinal neovascularization in the OIR model. Additional deletion of one copy of arginase 1 did not improve the vascular pathology. Analyses of peroxynitrite by quantitation of its biomarker nitrotyrosine, superoxide by dihydroethidium imaging and NO formation by diaminofluoroscein imaging showed that the protective actions of arginase 2 deletion were associated with blockade of superoxide and peroxynitrite formation and normalization of NOS activity. Conclusions Our data demonstrate the involvement of arginase activity and arginase 2 expression in hyperoxia-induced vascular injury. Arginase 2 deletion prevents hyperoxia-induced retinal vascular injury by preventing NOS uncoupling resulting in decreased reactive oxygen species formation and increased nitric oxide bioavailability.
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Affiliation(s)
- Jutamas Suwanpradid
- Vascular Biology Center, Georgia Regents University, Augusta, Georgia, United States of America
- Culver Vision Discovery Institute, Georgia Regents University, Augusta, Georgia, United States of America
| | - Modesto Rojas
- Vascular Biology Center, Georgia Regents University, Augusta, Georgia, United States of America
- Culver Vision Discovery Institute, Georgia Regents University, Augusta, Georgia, United States of America
- Department of Pharmacology and Toxicology, Department of Cellular Biology & Anatomy, Georgia Regents University, Augusta, Georgia, United States of America
| | - M. Ali Behzadian
- Vascular Biology Center, Georgia Regents University, Augusta, Georgia, United States of America
| | - R. William Caldwell
- Culver Vision Discovery Institute, Georgia Regents University, Augusta, Georgia, United States of America
- Department of Pharmacology and Toxicology, Department of Cellular Biology & Anatomy, Georgia Regents University, Augusta, Georgia, United States of America
| | - Ruth B. Caldwell
- Vascular Biology Center, Georgia Regents University, Augusta, Georgia, United States of America
- Culver Vision Discovery Institute, Georgia Regents University, Augusta, Georgia, United States of America
- Charlie Norwood VA Medical Center, Augusta, Georgia, United States of America
- * E-mail:
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