1
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Ebrahimi M, Sivaprasad S, Thompson P, Perry G. Retinal Neurodegeneration in Euglycemic Hyperinsulinemia, Prediabetes, and Diabetes. Ophthalmic Res 2022; 66:385-397. [PMID: 36463857 DOI: 10.1159/000528503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2023]
Abstract
Diabetic retinopathy (DR) is a challenging public health problem mainly because of its growing prevalence and risk of blindness. In general, our current knowledge and practice have failed to prevent the onset or progression of DR to sight-threatening complications. While there are treatment options for sight-threatening complications of DR, it is crucial to pay more attention to the early stages of DR to decrease its prevalence. Growing evidence suggests many pathologic changes occur before clinical presentations of DR in euglycemic hyperinsulinemia, prediabetes, and diabetes. These pathological changes occur in retinal neurons, glia, and microvasculature. A new focus on these preclinical pathologies - especially on hyperinsulinemia - may provide further insight into disease mechanisms, endpoints for clinical trials, and druggable targets in early disease. Here, we review the current evidence on the pathophysiological changes reported in preclinical DR and appraise preventive and treatment options for DR.
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Affiliation(s)
- Moein Ebrahimi
- Network of Immunity in Infection, Malignancy, and Autoimmunity, Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Sobha Sivaprasad
- NIHR Moorfields Biomedical Research Centre, Moorfields Eye Hospital, London, UK
| | - Paul Thompson
- Imaging Genetics Center, Mark and Mary Stevens Institute for Neuroimaging and Informatics, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - George Perry
- Department of Biology, University of Texas and San Antonio, San Antonio, Texas, USA
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2
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Ou K, Li Y, Liu L, Li H, Cox K, Wu J, Liu J, Dick AD. Recent developments of neuroprotective agents for degenerative retinal disorders. Neural Regen Res 2022; 17:1919-1928. [PMID: 35142668 PMCID: PMC8848613 DOI: 10.4103/1673-5374.335140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Retinal degeneration is a debilitating ocular complication characterized by the progressive loss of photoreceptors and other retinal neurons, which are caused by a group of retinal diseases affecting various age groups, and increasingly prevalent in the elderly. Age-related macular degeneration, diabetic retinopathy and glaucoma are among the most common complex degenerative retinal disorders, posing significant public health problems worldwide largely due to the aging society and the lack of effective therapeutics. Whilst pathoetiologies vary, if left untreated, loss of retinal neurons can result in an acquired degeneration and ultimately severe visual impairment. Irrespective of underlined etiology, loss of neurons and supporting cells including retinal pigment epithelium, microvascular endothelium, and glia, converges as the common endpoint of retinal degeneration and therefore discovery or repurposing of therapies to protect retinal neurons directly or indirectly are under intensive investigation. This review overviews recent developments of potential neuroprotectants including neuropeptides, exosomes, mitochondrial-derived peptides, complement inhibitors, senolytics, autophagy enhancers and antioxidants either still experimentally or in clinical trials. Effective treatments that possess direct or indirect neuroprotective properties would significantly lift the burden of visual handicap.
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Affiliation(s)
- Kepeng Ou
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, IATTI, Chongqing University of Arts and Sciences, Chongqing, China; Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Youjian Li
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, IATTI, Chongqing University of Arts and Sciences, Chongqing, China; Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Ling Liu
- Department of Ophthalmology, Yongchuan Hospital, Chongqing Medical University, Chongqing, China
| | - Hua Li
- Department of Ophthalmology, Yongchuan Hospital, Chongqing Medical University, Chongqing, China
| | - Katherine Cox
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Jiahui Wu
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK; Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian Liu
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Andrew D Dick
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol; Institute of Ophthalmology, University College London, London; National Institute for Health Research Biomedical Research Centre, Moorfields Eye Hospital, London, UK
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3
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Pöstyéni E, Ganczer A, Kovács-Valasek A, Gabriel R. Relevance of Peptide Homeostasis in Metabolic Retinal Degenerative Disorders: Curative Potential in Genetically Modified Mice. Front Pharmacol 2022; 12:808315. [PMID: 35095518 PMCID: PMC8793341 DOI: 10.3389/fphar.2021.808315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/20/2021] [Indexed: 11/19/2022] Open
Abstract
The mammalian retina contains approximately 30 neuropeptides that are synthetized by different neuronal cell populations, glia, and the pigmented epithelium. The presence of these neuropeptides leaves a mark on normal retinal molecular processes and physiology, and they are also crucial in fighting various pathologies (e.g., diabetic retinopathy, ischemia, age-related pathologies, glaucoma) because of their protective abilities. Retinal pathologies of different origin (metabolic, genetic) are extensively investigated by genetically manipulated in vivo mouse models that help us gain a better understanding of the molecular background of these pathomechanisms. These models offer opportunities to manipulate gene expression in different cell types to help reveal their roles in the preservation of retinal health or identify malfunction during diseases. In order to assess the current status of transgenic technologies available, we have conducted a literature survey focused on retinal disorders of metabolic origin, zooming in on the role of retinal neuropeptides in diabetic retinopathy and ischemia. First, we identified those neuropeptides that are most relevant to retinal pathologies in humans and the two clinically most relevant models, mice and rats. Then we continued our analysis with metabolic disorders, examining neuropeptide-related pathways leading to systemic or cellular damage and rescue. Last but not least, we reviewed the available literature on genetically modified mouse strains to understand how the manipulation of a single element of any given pathway (e.g., signal molecules, receptors, intracellular signaling pathways) could lead either to the worsening of disease conditions or, more frequently, to substantial improvements in retinal health. Most attention was given to studies which reported successful intervention against specific disorders. For these experiments, a detailed evaluation will be given and the possible role of converging intracellular pathways will be discussed. Using these converging intracellular pathways, curative effects of peptides could potentially be utilized in fighting metabolic retinal disorders.
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Affiliation(s)
- Etelka Pöstyéni
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary
| | - Alma Ganczer
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary.,János Szentágothai Research Centre, University of Pécs, Pécs, Hungary
| | - Andrea Kovács-Valasek
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary
| | - Robert Gabriel
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary.,János Szentágothai Research Centre, University of Pécs, Pécs, Hungary
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4
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Ou K, Copland DA, Theodoropoulou S, Mertsch S, Li Y, Liu J, Schrader S, Liu L, Dick AD. Treatment of diabetic retinopathy through neuropeptide Y-mediated enhancement of neurovascular microenvironment. J Cell Mol Med 2020; 24:3958-3970. [PMID: 32141716 PMCID: PMC7171318 DOI: 10.1111/jcmm.15016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 12/02/2019] [Accepted: 12/27/2019] [Indexed: 12/12/2022] Open
Abstract
Diabetic retinopathy (DR) is one of the most severe clinical manifestations of diabetes mellitus and a major cause of blindness. DR is principally a microvascular disease, although the pathogenesis also involves metabolic reactive intermediates which induce neuronal and glial activation resulting in disruption of the neurovascular unit and regulation of the microvasculature. However, the impact of neural/glial activation in DR remains controversial, notwithstanding our understanding as to when neural/glial activation occurs in the course of disease. The objective of this study was to determine a potential protective role of neuropeptide Y (NPY) using an established model of DR permissive to N-methyl-D-aspartate (NMDA)-induced excitotoxic apoptosis of retinal ganglion cells (RGC) and vascular endothelial growth factor (VEGF)-induced vascular leakage. In vitro evaluation using primary retinal endothelial cells demonstrates that NPY promotes vascular integrity, demonstrated by maintained tight junction protein expression and reduced permeability in response to VEGF treatment. Furthermore, ex vivo assessment of retinal tissue explants shows that NPY can protect RGC from excitotoxic-induced apoptosis. In vivo clinical imaging and ex vivo tissue analysis in the diabetic model permitted assessment of NPY treatment in relation to neural and endothelial changes. The neuroprotective effects of NPY were confirmed by attenuating NMDA-induced retinal neural apoptosis and able to maintain inner retinal vascular integrity. These findings could have important clinical implications and offer novel therapeutic approaches for the treatment in the early stages of DR.
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Affiliation(s)
- Kepeng Ou
- College of Pharmacy, National and Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing University of Arts and Sciences, Chongqing, China.,Laboratory for Experimental Ophthalmology, University of Düsseldorf, Düsseldorf, Germany.,Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - David A Copland
- Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - Sofia Theodoropoulou
- Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - Sonja Mertsch
- Laboratory for Experimental Ophthalmology, University of Düsseldorf, Düsseldorf, Germany.,Department of Ophthalmology, Faculty of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Youjian Li
- College of Pharmacy, National and Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing University of Arts and Sciences, Chongqing, China.,Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - Jian Liu
- Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - Stefan Schrader
- Laboratory for Experimental Ophthalmology, University of Düsseldorf, Düsseldorf, Germany.,Department of Ophthalmology, Faculty of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Lei Liu
- Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - Andrew D Dick
- Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK.,National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital, University College London Institute of Ophthalmology, London, UK
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5
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Neuroprotective Peptides in Retinal Disease. J Clin Med 2019; 8:jcm8081146. [PMID: 31374938 PMCID: PMC6722704 DOI: 10.3390/jcm8081146] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 07/26/2019] [Accepted: 07/31/2019] [Indexed: 02/07/2023] Open
Abstract
In the pathogenesis of many disorders, neuronal death plays a key role. It is now assumed that neurodegeneration is caused by multiple and somewhat converging/overlapping death mechanisms, and that neurons are sensitive to unique death styles. In this respect, major advances in the knowledge of different types, mechanisms, and roles of neurodegeneration are crucial to restore the neuronal functions involved in neuroprotection. Several novel concepts have emerged recently, suggesting that the modulation of the neuropeptide system may provide an entirely new set of pharmacological approaches. Neuropeptides and their receptors are expressed widely in mammalian retinas, where they exert neuromodulatory functions including the processing of visual information. In multiple models of retinal diseases, different peptidergic substances play neuroprotective actions. Herein, we describe the novel advances on the protective roles of neuropeptides in the retina. In particular, we focus on the mechanisms by which peptides affect neuronal death/survival and the vascular lesions commonly associated with retinal neurodegenerative pathologies. The goal is to highlight the therapeutic potential of neuropeptide systems as neuroprotectants in retinal diseases.
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Christiansen AT, Sørensen NB, Haanes KA, Blixt FW, la Cour M, Warfvinge K, Klemp K, Woldbye DPD, Kiilgaard JF. Neuropeptide Y treatment induces retinal vasoconstriction and causes functional and histological retinal damage in a porcine ischaemia model. Acta Ophthalmol 2018; 96:812-820. [PMID: 30218483 DOI: 10.1111/aos.13806] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 04/04/2018] [Indexed: 01/10/2023]
Abstract
PURPOSE To investigate the effects of intravitreal neuropeptide Y (NPY) treatment following acute retinal ischaemia in an in vivo porcine model. In addition, we evaluated the vasoconstrictive potential of NPY on porcine retinal arteries ex vivo. METHODS Twelve pigs underwent induced retinal ischaemia by elevated intraocular pressure clamping the ocular perfusion pressure at 5 mmHg for 2 hr followed by intravitreal injection of NPY or vehicle. After 4 weeks, retinas were evaluated functionally by standard and global-flash multifocal electroretinogram (mfERG) and histologically by thickness of retinal layers and number of ganglion cells. Additionally, the vasoconstrictive effects of NPY and its involved receptors were tested using wire myographs and NPY receptor antagonists on porcine retinal arteries. RESULTS Intravitreal injection of NPY after induced ischaemia caused a significant reduction in the mean induced component (IC) amplitude ratio (treated/normal eye) compared to vehicle-treated eyes. This reduction was accompanied by histological damage, where NPY treatment reduced the mean thickness of inner retinal layers and number of ganglion cells. In retinal arteries, NPY-induced vasoconstriction to a plateau of approximately 65% of potassium-induced constriction. This effect appeared to be mediated via Y1 and Y2, but not Y5. CONCLUSION In seeming contrast to previous in vitro studies, intravitreal NPY treatment caused functional and histological damage compared to vehicle after a retinal ischaemic insult. Furthermore, we showed for the first time that NPY induces Y1- and Y2- but not Y5-mediated vasoconstriction in retinal arteries. This constriction could explain the worsening in vivo effect induced by NPY treatment following an ischaemic insult and suggests that future studies on exploring the neuroprotective effects of NPY might focus on other receptors than Y1 and Y2.
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Affiliation(s)
- Anders T. Christiansen
- Laboratory of Neural Plasticity; Department of Neuroscience; University of Copenhagen; Copenhagen Denmark
- Department of Ophthalmology; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
| | - Nina B. Sørensen
- Department of Ophthalmology; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
| | - Kristian A. Haanes
- Department of Clinical Experimental Research; Glostrup Research Institute; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
| | - Frank W. Blixt
- Department of Clinical Sciences; Division of Experimental Vascular Research; Lund University; Lund Sweden
| | - Morten la Cour
- Department of Ophthalmology; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
| | - Karin Warfvinge
- Department of Clinical Experimental Research; Glostrup Research Institute; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
| | - Kristian Klemp
- Department of Ophthalmology; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
| | - David P. D. Woldbye
- Laboratory of Neural Plasticity; Department of Neuroscience; University of Copenhagen; Copenhagen Denmark
| | - Jens F. Kiilgaard
- Department of Ophthalmology; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
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7
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Campos EJ, Martins J, Brudzewsky D, Correia S, Santiago AR, Woldbye DP, Ambrósio AF. Impact of type 1 diabetes mellitus and sitagliptin treatment on the neuropeptide Y system of rat retina. Clin Exp Ophthalmol 2018; 46:783-795. [PMID: 29442423 DOI: 10.1111/ceo.13176] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 02/06/2018] [Accepted: 02/10/2018] [Indexed: 11/28/2022]
Abstract
BACKGROUND Neuropeptide Y (NPY) is a neuromodulator that is expressed in the retina. Increasing evidence suggests that NPY has pronounced anti-inflammatory effects, which might depend on the inhibition of dipeptidyl-peptidase-IV (DPP-IV). The aim of this study was to investigate the impact of type 1 diabetes mellitus (DM) and sitagliptin, a DPP-IV inhibitor, on the NPY system in the retina using an animal model. METHODS Type 1 DM was induced in male Wistar rats by an intraperitoneal injection of streptozotocin. Starting 2 weeks after DM onset, animals were treated orally with sitagliptin (5 mg/kg.day) for 2 weeks. The expression of NPY and NPY receptors (Y1 , Y2 and Y5 receptors) was measured by quantitative polymerase chain reaction, Western blot and/or enzyme-linked immunosorbent assay. The immunoreactivity of NPY and NPY receptors was evaluated by immunohistochemistry, and the [35 S]GTPγS binding assay was used to assess the functional binding of NPY receptors. RESULTS DM decreased the mRNA levels of NPY in the retina, as well as the protein levels of NPY and Y5 receptor. No changes were detected in the localization of NPY and NPY receptors in the retina and in the functional binding of NPY to all receptors. Sitagliptin alone reduced retinal NPY mRNA levels. The effects of DM on the NPY system were not affected by sitagliptin. CONCLUSION DM modestly affects the NPY system in the retina and these effects are not prevented by sitagliptin treatment. These observations suggest that DPP-IV enzyme is not underlying the NPY changes detected in the retina induced by type 1 DM.
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Affiliation(s)
- Elisa J Campos
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - João Martins
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Dan Brudzewsky
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Sandra Correia
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Ana R Santiago
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, Portugal
| | - David Pd Woldbye
- Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - António F Ambrósio
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, Portugal
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8
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Christiansen AT, Kiilgaard JF, Klemp K, Woldbye DPD, Hannibal J. Localization, distribution, and connectivity of neuropeptide Y in the human and porcine retinas-A comparative study. J Comp Neurol 2018; 526:1877-1895. [DOI: 10.1002/cne.24455] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/27/2018] [Accepted: 03/29/2018] [Indexed: 12/24/2022]
Affiliation(s)
| | - Jens Folke Kiilgaard
- Department of Ophthalmology; Copenhagen University Hospital, Rigshospitalet; Denmark
| | - Kristian Klemp
- Department of Ophthalmology; Copenhagen University Hospital, Rigshospitalet; Denmark
| | - David Paul Drucker Woldbye
- Laboratory of Neural Plasticity; Center for Neuroscience, Faculty of Health Sciences, University of Copenhagen; Denmark
| | - Jens Hannibal
- Department of Clinical Biochemistry; Copenhagen University Hospital, Bispebjerg Hospital; Copenhagen Denmark
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9
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Effects of Neuropeptide Y on Stem Cells and Their Potential Applications in Disease Therapy. Stem Cells Int 2017; 2017:6823917. [PMID: 29109742 PMCID: PMC5646323 DOI: 10.1155/2017/6823917] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 08/01/2017] [Accepted: 08/08/2017] [Indexed: 01/04/2023] Open
Abstract
Neuropeptide Y (NPY), a 36-amino acid peptide, is widely distributed in the central and peripheral nervous systems and other peripheral tissues. It takes part in regulating various biological processes including food intake, circadian rhythm, energy metabolism, and neuroendocrine secretion. Increasing evidence indicates that NPY exerts multiple regulatory effects on stem cells. As a kind of primitive and undifferentiated cells, stem cells have the therapeutic potential to replace damaged cells, secret paracrine molecules, promote angiogenesis, and modulate immunity. Stem cell-based therapy has been demonstrated effective and considered as one of the most promising treatments for specific diseases. However, several limitations still hamper its application, such as poor survival and low differentiation and integration rates of transplanted stem cells. The regulatory effects of NPY on stem cell survival, proliferation, and differentiation may be helpful to overcome these limitations and facilitate the application of stem cell-based therapy. In this review, we summarized the regulatory effects of NPY on stem cells and discussed their potential applications in disease therapy.
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10
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Martins J, Elvas F, Brudzewsky D, Martins T, Kolomiets B, Tralhão P, Gøtzsche CR, Cavadas C, Castelo-Branco M, Woldbye DPD, Picaud S, Santiago AR, Ambrósio AF. Activation of Neuropeptide Y Receptors Modulates Retinal Ganglion Cell Physiology and Exerts Neuroprotective Actions In Vitro. ASN Neuro 2015; 7:7/4/1759091415598292. [PMID: 26311075 PMCID: PMC4552225 DOI: 10.1177/1759091415598292] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Neuropeptide Y (NPY) is expressed in mammalian retina but the location and potential modulatory effects of NPY receptor activation remain largely unknown. Retinal ganglion cell (RGC) death is a hallmark of several retinal degenerative diseases, particularly glaucoma. Using purified RGCs and ex vivo rat retinal preparations, we have measured RGC intracellular free calcium concentration ([Ca2+]i) and RGC spiking activity, respectively. We found that NPY attenuated the increase in the [Ca2+]i triggered by glutamate mainly via Y1 receptor activation. Moreover, (Leu31, Pro34)−NPY, a Y1/Y5 receptor agonist, increased the initial burst response of OFF-type RGCs, although no effect was observed on RGC spontaneous spiking activity. The Y1 receptor activation was also able to directly modulate RGC responses by attenuating the NMDA-induced increase in RGC spiking activity. These results suggest that Y1 receptor activation, at the level of inner or outer plexiform layers, leads to modulation of RGC receptive field properties. Using in vitro cultures of rat retinal explants exposed to NMDA, we found that NPY pretreatment prevented NMDA-induced cell death. However, in an animal model of retinal ischemia-reperfusion injury, pretreatment with NPY or (Leu31, Pro34)−NPY was not able to prevent apoptosis or rescue RGCs. In conclusion, we found modulatory effects of NPY application that for the first time were detected at the level of RGCs. However, further studies are needed to evaluate whether NPY neuroprotective actions detected in retinal explants can be translated into animal models of retinal degenerative diseases.
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Affiliation(s)
- João Martins
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal
| | - Filipe Elvas
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal
| | - Dan Brudzewsky
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal
| | - Tânia Martins
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal
| | - Bogdan Kolomiets
- Sorbonne Universités, UPMC Univ Paris 06, Institut de la Vision, UMR_S968, 75012 Paris, France
| | - Pedro Tralhão
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal
| | - Casper R Gøtzsche
- Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Cláudia Cavadas
- CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Miguel Castelo-Branco
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal
| | - David P D Woldbye
- Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Serge Picaud
- Sorbonne Universités, UPMC Univ Paris 06, Institut de la Vision, UMR_S968, 75012 Paris, France
| | - Ana R Santiago
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - António F Ambrósio
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
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Santos-Carvalho A, Ambrósio AF, Cavadas C. Neuropeptide Y system in the retina: From localization to function. Prog Retin Eye Res 2015; 47:19-37. [DOI: 10.1016/j.preteyeres.2015.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 03/05/2015] [Accepted: 03/10/2015] [Indexed: 01/10/2023]
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12
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Hanumunthadu D, Dehabadi MH, Cordeiro MF. Neuroprotection in glaucoma: current and emerging approaches. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/17469899.2014.892415] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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13
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Santos-Carvalho A, Álvaro AR, Martins J, Ambrósio AF, Cavadas C. Emerging novel roles of neuropeptide Y in the retina: from neuromodulation to neuroprotection. Prog Neurobiol 2013; 112:70-9. [PMID: 24184719 DOI: 10.1016/j.pneurobio.2013.10.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 10/14/2013] [Accepted: 10/15/2013] [Indexed: 12/11/2022]
Abstract
Neuropeptide Y (NPY) and NPY receptors are widely expressed in the central nervous system, including the retina. Retinal cells, in particular neurons, astrocytes, and Müller, microglial and endothelial cells express this peptide and its receptors (Y1, Y2, Y4 and/or Y5). Several studies have shown that NPY is expressed in the retina of various mammalian and non-mammalian species. However, studies analyzing the distribution of NPY receptors in the retina are still scarce. Although the physiological roles of NPY in the retina have not been completely elucidated, its early expression strongly suggests that NPY may be involved in the development of retinal circuitry. NPY inhibits the increase in [Ca(2+)]i triggered by elevated KCl in retinal neurons, protects retinal neural cells against toxic insults and induces the proliferation of retinal progenitor cells. In this review, we will focus on the roles of NPY in the retina, specifically proliferation, neuromodulation and neuroprotection. Alterations in the NPY system in the retina might contribute to the pathogenesis of retinal degenerative diseases, such as diabetic retinopathy and glaucoma, and NPY and its receptors might be viewed as potentially novel therapeutic targets.
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Affiliation(s)
- Ana Santos-Carvalho
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - Ana Rita Álvaro
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Department of Biology and Environment, University of Trás-os-Montes and Alto Douro, Apartado 1013, 5001-801 Vila Real, Portugal
| | - João Martins
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
| | - António Francisco Ambrósio
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal; AIBILI-Association for Innovation and Biomedical Research on Light and Image, Azinhaga Santa Comba, Celas, 3000-548 Coimbra, Portugal
| | - Cláudia Cavadas
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal.
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Gábriel R. Neuropeptides and diabetic retinopathy. Br J Clin Pharmacol 2013; 75:1189-201. [PMID: 23043302 DOI: 10.1111/bcp.12003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 10/02/2012] [Indexed: 12/21/2022] Open
Abstract
Diabetic retinopathy, a common complication of diabetes, develops in 75% of patients with type 1 and 50% of patients with type 2 diabetes, progressing to legal blindness in about 5%. In the recent years, considerable efforts have been put into finding treatments for this condition. It has been discovered that peptidergic mechanisms (neuropeptides and their analogues, activating a diverse array of signal transduction pathways through their multiple receptors) are potentially important for consideration in drug development strategies. A considerable amount of knowledge has been accumulated over the last three decades on human retinal neuropeptides and those elements in the pathomechanisms of diabetic retinopathy which might be related to peptidergic signal transduction. Here, human retinal neuropeptides and their receptors are reviewed, along with the theories relevant to the pathogenesis of diabetic retinopathy both in humans and in experimental models. By collating this information, the curative potential of certain neupeptides and their analogues/antagonists can also be discussed, along with the existing clinical treatments of diabetic retinopathy. The most promising peptidergic pathways for which treatment strategies may be developed at present are stimulation of the somatostatin-related pathway and the pituitary adenylyl cyclase-activating polypeptide-related pathway or inhibition of angiotensinergic mechanisms. These approaches may result in the inhibition of vascular endothelial growth factor production and neuronal apoptosis; therefore, both the optical quality of the image and the processing capability of the neural circuit in the retina may be saved.
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Affiliation(s)
- Robert Gábriel
- Department of Experimental Zoology and Neurobiology, University of Pécs, H-7621, Pécs, Hungary.
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Neuropeptide Y receptors activation protects rat retinal neural cells against necrotic and apoptotic cell death induced by glutamate. Cell Death Dis 2013; 4:e636. [PMID: 23681231 PMCID: PMC3674367 DOI: 10.1038/cddis.2013.160] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
It has been claimed that glutamate excitotoxicity might have a role in the pathogenesis of several retinal degenerative diseases, including glaucoma and diabetic retinopathy. Neuropeptide Y (NPY) has neuroprotective properties against excitotoxicity in the hippocampus, through the activation of Y1, Y2 and/or Y5 receptors. The principal objective of this study is to investigate the potential protective role of NPY against glutamate-induced toxicity in rat retinal cells (in vitro and in an animal model), unraveling the NPY receptors and intracellular mechanisms involved. Rat retinal neural cell cultures were prepared from newborn Wistar rats (P3-P5) and exposed to glutamate (500 μM) for 24 h. Necrotic cell death was evaluated by propidium iodide (PI) assay and apoptotic cell death using TUNEL and caspase-3 assays. The cell types present in culture were identified by immunocytochemistry. The involvement of NPY receptors was assessed using selective agonists and antagonists. Pre-treatment of cells with NPY (100 nM) inhibited both necrotic cell death (PI-positive cells) and apoptotic cell death (TUNEL-positive cells and caspase 3-positive cells) triggered by glutamate, with the neurons being the cells most strongly affected. The activation of NPY Y2, Y4 and Y5 receptors inhibited necrotic cell death, while apoptotic cell death was only prevented by the activation of NPY Y5 receptor. Moreover, NPY neuroprotective effect was mediated by the activation of PKA and p38K. In the animal model, NPY (2.35 nmol) was intravitreally injected 2 h before glutamate (500 nmol) injection into the vitreous. The protective role of NPY was assessed 24 h after glutamate (or saline) injection by TUNEL assay and Brn3a (marker of ganglion cells) immunohistochemistry. NPY inhibited the increase in the number of TUNEL-positive cells and the decrease in the number of Brn3a-positive cells induced by glutamate. In conclusion, NPY and NPY receptors can be considered potential targets to treat retinal degenerative diseases, such as glaucoma and diabetic retinopathy.
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Dubois CJ, Ramamoorthy P, Whim MD, Liu SJ. Activation of NPY type 5 receptors induces a long-lasting increase in spontaneous GABA release from cerebellar inhibitory interneurons. J Neurophysiol 2011; 107:1655-65. [PMID: 22190627 DOI: 10.1152/jn.00755.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Neuropeptide Y (NPY), a widely distributed neuropeptide in the central nervous system, can transiently suppress inhibitory synaptic transmission and alter membrane excitability via Y2 and Y1 receptors (Y2rs and Y1rs), respectively. Although many GABAergic neurons express Y5rs, the functional role of these receptors in inhibitory neurons is not known. Here, we investigated whether activation of Y5rs can modulate inhibitory transmission in cerebellar slices. Unexpectedly, application of NPY triggered a long-lasting increase in the frequency of miniature inhibitory postsynaptic currents in stellate cells. NPY also induced a sustained increase in spontaneous GABA release in cultured cerebellar neurons. When cerebellar cultures were examined for Y5r immunoreactivity, the staining colocalized with that of VGAT, a presynaptic marker for GABAergic cells, suggesting that Y5rs are located in the presynaptic terminals of inhibitory neurons. RT-PCR experiments confirmed the presence of Y5r mRNA in the cerebellum. The NPY-induced potentiation of GABA release was blocked by Y5r antagonists and mimicked by application of a selective peptide agonist for Y5r. Thus Y5r activation is necessary and sufficient to trigger an increase in GABA release. Finally, the potentiation of inhibitory transmission could not be reversed by a Y5r antagonist once it was initiated, consistent with the development of a long-term potentiation. These results indicate that activation of presynaptic Y5rs induces a sustained increase in spontaneous GABA release from inhibitory neurons in contrast to the transient suppression of inhibitory transmission that is characteristic of Y1r and Y2r activation. Our findings thus reveal a novel role of presynaptic Y5rs in inhibitory interneurons in regulating GABA release and suggest that these receptors could play a role in shaping neuronal network activity in the cerebellum.
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Affiliation(s)
- C J Dubois
- Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA
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Sousa-Ferreira L, Álvaro AR, Aveleira C, Santana M, Brandão I, Kügler S, Pereira de Almeida L, Cavadas C. Proliferative hypothalamic neurospheres express NPY, AGRP, POMC, CART and Orexin-A and differentiate to functional neurons. PLoS One 2011; 6:e19745. [PMID: 21589937 PMCID: PMC3092771 DOI: 10.1371/journal.pone.0019745] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2010] [Accepted: 04/15/2011] [Indexed: 01/12/2023] Open
Abstract
Some pathological conditions with feeding pattern alterations, including obesity and Huntington disease (HD) are associated with hypothalamic dysfunction and neuronal cell death. Additionally, the hypothalamus is a neurogenic region with the constitutive capacity to generate new cells of neuronal lineage, in adult rodents. The aim of the present work was to evaluate the expression of feeding-related neuropeptides in hypothalamic progenitor cells and their capacity to differentiate to functional neurons which have been described to be affected by hypothalamic dysfunction. Our study shows that hypothalamic progenitor cells from rat embryos grow as floating neurospheres and express the feeding-related neuropeptides Neuropeptide Y (NPY), Agouti-related Protein (AGRP), Pro-OpioMelanocortin (POMC), Cocaine-and-Amphetamine Responsive Transcript (CART) and Orexin-A/Hypocretin-1. Moreover the relative mRNA expression of NPY and POMC increases during the expansion of hypothalamic neurospheres in proliferative conditions. Mature neurons were obtained from the differentiation of hypothalamic progenitor cells including NPY, AGRP, POMC, CART and Orexin-A positive neurons. Furthermore the relative mRNA expression of NPY, CART and Orexin-A increases after the differentiation of hypothalamic neurospheres. Similarly to the adult hypothalamic neurons the neurospheres-derived neurons express the glutamate transporter EAAT3. The orexigenic and anorexigenic phenotype of these neurons was identified by functional response to ghrelin and leptin hormones, respectively. This work demonstrates the presence of appetite-related neuropeptides in hypothalamic progenitor cells and neurons obtained from the differentiation of hypothalamic neurospheres, including the neuronal phenotypes that have been described by others as being affected by hypothalamic neurodegeneration. These in vitro models can be used to study hypothalamic progenitor cells aiming a therapeutic intervention to mitigate feeding dysfunction that are associated with hypothalamic neurodegeneration.
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Affiliation(s)
- Lígia Sousa-Ferreira
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Ana Rita Álvaro
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Department of Biology and Environment, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
| | - Célia Aveleira
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Magda Santana
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Inês Brandão
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Sebastian Kügler
- Department of Neurology, Viral Vectors Laboratory, University Medicine Göttingen, Göttingen, Germany
| | - Luís Pereira de Almeida
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Cláudia Cavadas
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
- * E-mail:
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