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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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Correa‐da‐Silva F, Fliers E, Swaab DF, Yi C. Hypothalamic neuropeptides and neurocircuitries in Prader Willi syndrome. J Neuroendocrinol 2021; 33:e12994. [PMID: 34156126 PMCID: PMC8365683 DOI: 10.1111/jne.12994] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 04/19/2021] [Accepted: 05/04/2021] [Indexed: 02/06/2023]
Abstract
Prader-Willi Syndrome (PWS) is a rare and incurable congenital neurodevelopmental disorder, resulting from the absence of expression of a group of genes on the paternally acquired chromosome 15q11-q13. Phenotypical characteristics of PWS include infantile hypotonia, short stature, incomplete pubertal development, hyperphagia and morbid obesity. Hypothalamic dysfunction in controlling body weight and food intake is a hallmark of PWS. Neuroimaging studies have demonstrated that PWS subjects have abnormal neurocircuitry engaged in the hedonic and physiological control of feeding behavior. This is translated into diminished production of hypothalamic effector peptides which are responsible for the coordination of energy homeostasis and satiety. So far, studies with animal models for PWS and with human post-mortem hypothalamic specimens demonstrated changes particularly in the infundibular and the paraventricular nuclei of the hypothalamus, both in orexigenic and anorexigenic neural populations. Moreover, many PWS patients have a severe endocrine dysfunction, e.g. central hypogonadism and/or growth hormone deficiency, which may contribute to the development of increased fat mass, especially if left untreated. Additionally, the role of non-neuronal cells, such as astrocytes and microglia in the hypothalamic dysregulation in PWS is yet to be determined. Notably, microglial activation is persistently present in non-genetic obesity. To what extent microglia, and other glial cells, are affected in PWS is poorly understood. The elucidation of the hypothalamic dysfunction in PWS could prove to be a key feature of rational therapeutic management in this syndrome. This review aims to examine the evidence for hypothalamic dysfunction, both at the neuropeptidergic and circuitry levels, and its correlation with the pathophysiology of PWS.
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Affiliation(s)
- Felipe Correa‐da‐Silva
- Department of Endocrinology and MetabolismAmsterdam Gastroenterology Endocrinology and MetabolismAmsterdam University Medical Center (UMC)University of AmsterdamAmsterdamThe Netherlands
- Laboratory of EndocrinologyAmsterdam University Medical Center (UMC)University of AmsterdamAmsterdamThe Netherlands
- Department of Neuropsychiatric DisordersNetherlands Institute for NeuroscienceAn Institute of the Royal Netherlands Academy of Arts and SciencesAmsterdamThe Netherlands
| | - Eric Fliers
- Department of Endocrinology and MetabolismAmsterdam Gastroenterology Endocrinology and MetabolismAmsterdam University Medical Center (UMC)University of AmsterdamAmsterdamThe Netherlands
| | - Dick F. Swaab
- Department of Neuropsychiatric DisordersNetherlands Institute for NeuroscienceAn Institute of the Royal Netherlands Academy of Arts and SciencesAmsterdamThe Netherlands
| | - Chun‐Xia Yi
- Department of Endocrinology and MetabolismAmsterdam Gastroenterology Endocrinology and MetabolismAmsterdam University Medical Center (UMC)University of AmsterdamAmsterdamThe Netherlands
- Laboratory of EndocrinologyAmsterdam University Medical Center (UMC)University of AmsterdamAmsterdamThe Netherlands
- Department of Neuropsychiatric DisordersNetherlands Institute for NeuroscienceAn Institute of the Royal Netherlands Academy of Arts and SciencesAmsterdamThe Netherlands
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4
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Chen WC, Liu YB, Liu WF, Zhou YY, He HF, Lin S. Neuropeptide Y Is an Immunomodulatory Factor: Direct and Indirect. Front Immunol 2020; 11:580378. [PMID: 33123166 PMCID: PMC7573154 DOI: 10.3389/fimmu.2020.580378] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/18/2020] [Indexed: 12/12/2022] Open
Abstract
Neuropeptide Y (NPY), which is widely distributed in the nervous system, is involved in regulating a variety of biological processes, including food intake, energy metabolism, and emotional expression. However, emerging evidence points to NPY also as a critical transmitter between the nervous system and immune system, as well as a mediator produced and released by immune cells. In vivo and in vitro studies based on gene-editing techniques and specific NPY receptor agonists and antagonists have demonstrated that NPY is responsible for multifarious direct modulations on immune cells by acting on NPY receptors. Moreover, via the central or peripheral nervous system, NPY is closely connected to body temperature regulation, obesity development, glucose metabolism, and emotional expression, which are all immunomodulatory factors for the immune system. In this review, we focus on the direct role of NPY in immune cells and particularly discuss its indirect impact on the immune response.
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Affiliation(s)
- Wei-Can Chen
- Department of Anesthesiology, The Second Affiliated Hospital, Fujian Medical University, Quanzhou, China
| | - Yi-Bin Liu
- Department of Anesthesiology, The Second Affiliated Hospital, Fujian Medical University, Quanzhou, China
| | - Wei-Feng Liu
- Department of Anesthesiology, The Second Affiliated Hospital, Fujian Medical University, Quanzhou, China
| | - Ying-Ying Zhou
- Department of Anesthesiology, The Second Affiliated Hospital, Fujian Medical University, Quanzhou, China
| | - He-Fan He
- Department of Anesthesiology, The Second Affiliated Hospital, Fujian Medical University, Quanzhou, China
| | - Shu Lin
- Department of Anesthesiology, The Second Affiliated Hospital, Fujian Medical University, Quanzhou, China.,Centre of Neurological and Metabolic Research, The Second Affiliated Hospital, Fujian Medical University, Quanzhou, China.,Diabetes and Metabolism Division, Garvan Institute of Medical Research, Sydney, NSW, Australia
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5
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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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6
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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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7
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Caolo V, Roblain Q, Lecomte J, Carai P, Peters L, Cuijpers I, Robinson EL, Derks K, Sergeys J, Noël A, Jones EAV, Moons L, Heymans S. Resistance to retinopathy development in obese, diabetic and hypertensive ZSF1 rats: an exciting model to identify protective genes. Sci Rep 2018; 8:11922. [PMID: 30093686 PMCID: PMC6085379 DOI: 10.1038/s41598-018-29812-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 07/17/2018] [Indexed: 12/11/2022] Open
Abstract
Diabetic retinopathy (DR) is one of the major complications of diabetes, which eventually leads to blindness. Up to date, no animal model has yet shown all the co-morbidities often observed in DR patients. Here, we investigated whether obese 42 weeks old ZSF1 rat, which spontaneously develops diabetes, hypertension and obesity, would be a suitable model to study DR. Although arteriolar tortuosity increased in retinas from obese as compared to lean (hypertensive only) ZSF1 rats, vascular density pericyte coverage, microglia number, vascular morphology and retinal thickness were not affected by diabetes. These results show that, despite high glucose levels, obese ZSF1 rats did not develop DR. Such observations prompted us to investigate whether the expression of genes, possibly able to contain DR development, was affected. Accordingly, mRNA sequencing analysis showed that genes (i.e. Npy and crystallins), known to have a protective role, were upregulated in retinas from obese ZSF1 rats. Lack of retina damage, despite obesity, hypertension and diabetes, makes the 42 weeks of age ZSF1 rats a suitable animal model to identify genes with a protective function in DR. Further characterisation of the identified genes and downstream pathways could provide more therapeutic targets for the treat DR.
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Affiliation(s)
- Vincenza Caolo
- Department of Cardiovascular Sciences, Centre for Molecular and Vascular Biology, KU Leuven, Belgium.
| | - Quentin Roblain
- Department of Cardiology, CARIM School for Cardiovascular Diseases Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.,Laboratory of Tumor and Development Biology, GIGA-Cancer, University of Liège, Liège, Belgium
| | - Julie Lecomte
- Laboratory of Tumor and Development Biology, GIGA-Cancer, University of Liège, Liège, Belgium
| | - Paolo Carai
- Department of Cardiovascular Sciences, Centre for Molecular and Vascular Biology, KU Leuven, Belgium
| | - Linsey Peters
- Department of Cardiology, CARIM School for Cardiovascular Diseases Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Ilona Cuijpers
- Department of Cardiovascular Sciences, Centre for Molecular and Vascular Biology, KU Leuven, Belgium.,Department of Cardiology, CARIM School for Cardiovascular Diseases Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Emma Louise Robinson
- Department of Cardiology, CARIM School for Cardiovascular Diseases Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Kasper Derks
- Department of Genetics and Cell Biology, CARIM School for Cardiovascular Diseases Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Jurgen Sergeys
- Laboratory of Neural Circuit Development and Regeneration, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium
| | - Agnès Noël
- Laboratory of Tumor and Development Biology, GIGA-Cancer, University of Liège, Liège, Belgium
| | - Elizabeth A V Jones
- Department of Cardiovascular Sciences, Centre for Molecular and Vascular Biology, KU Leuven, Belgium
| | - Lieve Moons
- Laboratory of Neural Circuit Development and Regeneration, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium
| | - Stephane Heymans
- Department of Cardiovascular Sciences, Centre for Molecular and Vascular Biology, KU Leuven, Belgium.,Department of Cardiology, CARIM School for Cardiovascular Diseases Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.,The Netherlands Heart Institute, Nl-HI, Utrecht, The Netherlands
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8
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Neuropeptides and Microglial Activation in Inflammation, Pain, and Neurodegenerative Diseases. Mediators Inflamm 2017; 2017:5048616. [PMID: 28154473 PMCID: PMC5244030 DOI: 10.1155/2017/5048616] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/26/2016] [Accepted: 12/05/2016] [Indexed: 12/15/2022] Open
Abstract
Microglial cells are responsible for immune surveillance within the CNS. They respond to noxious stimuli by releasing inflammatory mediators and mounting an effective inflammatory response. This is followed by release of anti-inflammatory mediators and resolution of the inflammatory response. Alterations to this delicate process may lead to tissue damage, neuroinflammation, and neurodegeneration. Chronic pain, such as inflammatory or neuropathic pain, is accompanied by neuroimmune activation, and the role of glial cells in the initiation and maintenance of chronic pain has been the subject of increasing research over the last two decades. Neuropeptides are small amino acidic molecules with the ability to regulate neuronal activity and thereby affect various functions such as thermoregulation, reproductive behavior, food and water intake, and circadian rhythms. Neuropeptides can also affect inflammatory responses and pain sensitivity by modulating the activity of glial cells. The last decade has witnessed growing interest in the study of microglial activation and its modulation by neuropeptides in the hope of developing new therapeutics for treating neurodegenerative diseases and chronic pain. This review summarizes the current literature on the way in which several neuropeptides modulate microglial activity and response to tissue damage and how this modulation may affect pain sensitivity.
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9
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Neuropeptide Y (NPY) as a therapeutic target for neurodegenerative diseases. Neurobiol Dis 2016; 95:210-24. [PMID: 27461050 DOI: 10.1016/j.nbd.2016.07.022] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/29/2016] [Accepted: 07/20/2016] [Indexed: 12/16/2022] Open
Abstract
Neuropeptide Y (NPY) and NPY receptors are widely expressed in the mammalian central nervous system. Studies in both humans and rodent models revealed that brain NPY levels are altered in some neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, Huntington's disease and Machado-Joseph disease. In this review, we will focus on the roles of NPY in the pathological mechanisms of these disorders, highlighting NPY as a neuroprotective agent, as a neural stem cell proliferative agent, as an agent that increases trophic support, as a stimulator of autophagy and as an inhibitor of excitotoxicity and neuroinflammation. Moreover, the effect of NPY in some clinical manifestations commonly observed in Alzheimer's disease, Parkinson's disease, Huntington's disease and Machado-Joseph disease, such as depressive symptoms and body weight loss, are also discussed. In conclusion, this review highlights NPY system as a potential therapeutic target in neurodegenerative diseases.
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10
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Palavra F, Almeida L, Ambrósio AF, Reis F. Obesity and brain inflammation: a focus on multiple sclerosis. Obes Rev 2016; 17:211-24. [PMID: 26783119 DOI: 10.1111/obr.12363] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 10/25/2015] [Accepted: 11/09/2015] [Indexed: 02/06/2023]
Abstract
The increase in prevalence of obesity in industrialized societies is an indisputable fact. However, the apparent passive role played by adipocytes, in pathophysiological terms, has been gradually substituted by a metabolically active performance, relevant to many biochemical mechanisms that may contribute to a chronic low-grade inflammatory status, which increasingly imposes itself as a key feature of obesity. This chronic inflammatory status will have to be integrated into the complex equation of many diseases in which inflammation plays a crucial role. Multiple sclerosis (MS) is a chronic inflammatory condition typically confined to the central nervous system, and many work has been produced to find possible points of contact between the biology of this immune-mediated disease and obesity. So far, clinical data are not conclusive, but many biochemical features have been recently disclosed. Brain inflammation has been implicated in some of the mechanisms that lead to obesity, which has also been recognized as an important player in inducing some degree of immune dysfunction. In this review, we collected evidence that allows establishing bridges between obesity and MS. After considering epidemiological controversies, we will focus on possible shared mechanisms, as well as on the potential contributions that disease-modifying drugs may have on this apparent relationship of mutual interference.
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Affiliation(s)
- F Palavra
- Laboratory of Pharmacology & Experimental Therapeutics, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,Center for Neuroscience and Cell Biology-Institute for Biomedical Imaging and Life Sciences (CNC.IBILI) Research Consortium, University of Coimbra, Coimbra, Portugal
| | - L Almeida
- Laboratory of Pharmacology & Experimental Therapeutics, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - A F Ambrósio
- Laboratory of Pharmacology & Experimental Therapeutics, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,Center for Neuroscience and Cell Biology-Institute for Biomedical Imaging and Life Sciences (CNC.IBILI) Research Consortium, University of Coimbra, Coimbra, Portugal.,Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, Portugal
| | - F Reis
- Laboratory of Pharmacology & Experimental Therapeutics, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,Center for Neuroscience and Cell Biology-Institute for Biomedical Imaging and Life Sciences (CNC.IBILI) Research Consortium, University of Coimbra, Coimbra, Portugal
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11
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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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12
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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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13
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Geloso MC, Corvino V, Di Maria V, Marchese E, Michetti F. Cellular targets for neuropeptide Y-mediated control of adult neurogenesis. Front Cell Neurosci 2015; 9:85. [PMID: 25852477 PMCID: PMC4360818 DOI: 10.3389/fncel.2015.00085] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 02/23/2015] [Indexed: 12/14/2022] Open
Abstract
Neuropeptides are emerging as key regulators of stem cell niche activities in health and disease, both inside and outside the central nervous system (CNS). Among them, neuropeptide Y (NPY), one of the most abundant neuropeptides both in the nervous system and in non-neural districts, has become the focus of much attention for its involvement in a wide range of physiological and pathological conditions, including the modulation of different stem cell activities. In particular, a pro-neurogenic role of NPY has been evidenced in the neurogenic niche, where a direct effect on neural progenitors has been demonstrated, while different cellular types, including astrocytes, microglia and endothelial cells, also appear to be responsive to the peptide. The marked modulation of the NPY system during several pathological conditions that affect neurogenesis, including stress, seizures and neurodegeneration, further highlights the relevance of this peptide in the regulation of adult neurogenesis. In view of the considerable interest in understanding the mechanisms controlling neural cell fate, this review aims to summarize and discuss current data on NPY signaling in the different cellular components of the neurogenic niche in order to elucidate the complexity of the mechanisms underlying the modulatory properties of this peptide.
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Affiliation(s)
- Maria Concetta Geloso
- Institute of Anatomy and Cell Biology, Università Cattolica del Sacro Cuore Rome, Italy
| | - Valentina Corvino
- Institute of Anatomy and Cell Biology, Università Cattolica del Sacro Cuore Rome, Italy
| | - Valentina Di Maria
- Institute of Anatomy and Cell Biology, Università Cattolica del Sacro Cuore Rome, Italy
| | - Elisa Marchese
- Institute of Anatomy and Cell Biology, Università Cattolica del Sacro Cuore Rome, Italy
| | - Fabrizio Michetti
- Institute of Anatomy and Cell Biology, Università Cattolica del Sacro Cuore Rome, Italy
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14
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15
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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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16
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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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Malva JO, Xapelli S, Baptista S, Valero J, Agasse F, Ferreira R, Silva AP. Multifaces of neuropeptide Y in the brain--neuroprotection, neurogenesis and neuroinflammation. Neuropeptides 2012; 46:299-308. [PMID: 23116540 DOI: 10.1016/j.npep.2012.09.001] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 09/17/2012] [Accepted: 09/25/2012] [Indexed: 12/20/2022]
Abstract
Neuropeptide Y (NPY) has been implicated in the modulation of important features of neuronal physiology, including calcium homeostasis, neurotransmitter release and excitability. Moreover, NPY has been involved as an important modulator of hippocampal and thalamic circuits, receiving particular attention as an endogenous antiepileptic peptide and as a potential master regulator of feeding behavior. NPY not only inhibits excessive glutamate release (decreasing circuitry hyperexcitability) but also protects neurons from excitotoxic cell death. Furthermore, NPY has been involved in the modulation of the dynamics of dentate gyrus and subventricular zone neural stem cell niches. In both regions, NPY is part of the chemical resource of the neurogenic niche and acts through NPY Y1 receptors to promote neuronal differentiation. Interestingly, NPY is also considered a neuroimmune messenger. In this review, we highlight recent evidences concerning paracrine/autocrine actions of NPY involved in neuroprotection, neurogenesis and neuroinflammation. In summary, the three faces of NPY, discussed in the present review, may contribute to better understand the dynamics and cell fate decision in the brain parenchyma and in restricted areas of neurogenic niches, in health and disease.
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Affiliation(s)
- J O Malva
- Laboratory of Biochemistry and Cell Biology, Faculty of Medicine, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal.
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Gonçalves J, Ribeiro CF, Malva JO, Silva AP. Protective role of neuropeptide Y Y2receptors in cell death and microglial response following methamphetamine injury. Eur J Neurosci 2012; 36:3173-83. [DOI: 10.1111/j.1460-9568.2012.08232.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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20
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Localized retinal neuropeptide regulation of macrophage and microglial cell functionality. J Neuroimmunol 2010; 232:17-25. [PMID: 20965575 DOI: 10.1016/j.jneuroim.2010.09.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2010] [Revised: 09/21/2010] [Accepted: 09/23/2010] [Indexed: 11/20/2022]
Abstract
The functionality of immune cells is manipulated within the ocular microenvironment to protect the sensitive and non-regenerating light-gathering tissue from the collateral damage of inflammation. This is mediated partly by the constitutive presence of immunomodulating neuropeptides. Treating primary resting macrophages with soluble factors produced by the posterior eye induced co-expression of Arginase1 and NOS2. The neuropeptides alpha-melanocyte stimulating hormone and Neuropeptide Y alternatively activated the macrophages to co-express Arginase1 and NOS2 like myeloid suppressor cells. Similar co-expressing cells were found within healthy, but not in wounded retinas. Therefore, the healthy retina regulates macrophage functionality to the benefit of ocular immune privilege.
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Alvaro AR, Martins J, Araújo IM, Rosmaninho-Salgado J, Ambrósio AF, Cavadas C. Neuropeptide Y stimulates retinal neural cell proliferation--involvement of nitric oxide. J Neurochem 2010; 105:2501-10. [PMID: 18331583 DOI: 10.1111/j.1471-4159.2008.05334.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Neuropeptide Y (NPY) is a 36 amino acid peptide widely present in the CNS, including the retina. Previous studies have demonstrated that NPY promotes cell proliferation of rat post-natal hippocampal and olfactory epithelium precursor cells. The aim of this work was to investigate the role of NPY on cell proliferation of rat retinal neural cells. For this purpose, primary retinal cell cultures expressing NPY, and NPY Y(1), Y(2), Y(4) and Y(5) receptors [Alvaro et al., (2007) Neurochem. Int., 50, 757] were used. NPY (10-1000 nM) stimulated cell proliferation through the activation of NPY Y(1), Y(2) and Y(5) receptors. NPY also increased the number of proliferating neuronal progenitor cells (BrdU(+)/nestin(+) cells). The intracellular mechanisms coupled to NPY receptors activation that mediate the increase in cell proliferation were also investigated. The stimulatory effect of NPY on cell proliferation was reduced by L-nitroarginine-methyl-esther (L-NAME; 500 microM), a nitric oxide synthase inhibitor, 1H-[1,2,4]oxadiazolo-[4, 3-a]quinoxalin-1-one (ODQ; 20 microM), a soluble guanylyl cyclase inhibitor or U0126 (1 microM), an inhibitor of the extracellular signal-regulated kinase 1/2 (ERK 1/2). In conclusion, NPY stimulates retinal neural cell proliferation, and this effect is mediated through nitric oxide-cyclic GMP and ERK 1/2 pathways.
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Affiliation(s)
- Ana Rita Alvaro
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
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Nunes AF, Montero M, Franquinho F, Santos SD, Malva J, Zimmer J, Sousa MM. Transthyretin knockout mice display decreased susceptibility to AMPA-induced neurodegeneration. Neurochem Int 2009; 55:454-7. [DOI: 10.1016/j.neuint.2009.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 07/01/2009] [Accepted: 07/02/2009] [Indexed: 12/13/2022]
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Alvaro AR, Rosmaninho-Salgado J, Ambrósio AF, Cavadas C. Neuropeptide Y inhibits [Ca2+]i changes in rat retinal neurons through NPY Y1, Y4, and Y5 receptors. J Neurochem 2009; 109:1508-15. [PMID: 19344373 DOI: 10.1111/j.1471-4159.2009.06079.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Neuropeptide Y (NPY) and NPY receptors are widely distributed in the CNS, including the retina, but the role of NPY in the retina is largely unknown. The aim of this study was to investigate whether NPY modulates intracellular calcium concentration ([Ca(2+)](i)) changes in retinal neurons and identify the NPY receptors involved. As NPY decreased the [Ca(2+)](i) amplitudes evoked by 30 mM KCl in only 50% of neurons analyzed, we divided them in two populations: NPY-non-responsive neurons (Delta2/Delta1 > or = 0.80) and NPY-responsive neurons (Delta2/Delta1 < 0.80), being the Delta2/Delta1 the ratio between the amplitude of [Ca(2+)](i) increase evoked by the second (Delta2) and the first (Delta1) stimuli of KCl. The NPY Y(1)/Y(5), Y(4), and Y(5) receptor agonists (100 nM), but not the Y(2) receptor agonist (300 nM), inhibited the [Ca(2+)](i) increase induced by KCl. In addition, the inhibitory effect of NPY on evoked-[Ca(2+)](i) changes was reduced in the presence of the Y(1) or the Y(5) receptor antagonists. In conclusion, NPY inhibits KCl-evoked [Ca(2+)](i) increase in retinal neurons through the activation of NPY Y(1), Y(4), and Y(5) receptors. This effect may be viewed as a potential neuroprotective mechanism of NPY against retinal neurodegeneration.
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Affiliation(s)
- Ana Rita Alvaro
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
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Andrade da Costa BLDS, Kang KD, Rittenhouse KD, Osborne NN. The localization of PGE2 receptor subtypes in rat retinal cultures and the neuroprotective effect of the EP2 agonist butaprost. Neurochem Int 2009; 55:199-207. [PMID: 19524109 DOI: 10.1016/j.neuint.2009.02.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 02/10/2009] [Accepted: 02/25/2009] [Indexed: 01/05/2023]
Abstract
It is concluded from immunohistochemical that all four types of prostaglandin-E(2) (PGE(2)) (EP1, EP2, EP3 and EP4) receptors are associated with specific cell-types in primary rat retinal cultures. Analysis specifically of EP2 receptor immunoreactivity shows it to coexist with some neurones expressing Thy-1 and calbindin immunoreactivities as well as with vimentin-positive Müller cells. Moreover, exposure of cultures to the EP2 specific agonist butaprost (100 nM) for a period of 24h results in a generation of cAMP thus providing support for the functionality of EP2 receptors. Cell survival was significantly affected in cultures where the serum concentration was reduced from 10 to 1% for 24h. This was reflected by a reduction in the number of GABA-positive neurons and an elevation of released lactate dehydrogenase (LDH) into the culture medium. Moreover, a number of cells displayed a clear generation of reactive oxygen species (ROS) and a staining for the breakdown of DNA by the TUNEL procedure as an indicator for apoptosis. These negative effects were attenuated when butaprost (100 nM) was present during the serum reduction and 30 min before the insult. The present studies provide evidence to show that all PGE(2) receptor types exist in the retina of rat pups, remain functional when the retinal cells are cultured and that specific activation of EP2 receptors with butaprost can attenuate a detrimental insult caused by insufficient serum that may occur in situ by reduced trophic support.
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Affiliation(s)
- Belmira Lara da Silveira Andrade da Costa
- Departamento de Fisiologia e Farmacologia, Centro de Ciências Biológicas (CCB), CCB-UFPE, Av. Prof. Moraes Rego s/n, Cidade Universitária, 50670901 Recife, PE, Brazil
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Neuropeptide Y protects retinal neural cells against cell death induced by ecstasy. Neuroscience 2008; 152:97-105. [DOI: 10.1016/j.neuroscience.2007.12.027] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Revised: 12/09/2007] [Accepted: 12/10/2007] [Indexed: 01/28/2023]
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