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Papadogkonaki S, Spyridakos D, Lapokonstantaki E, Chaniotakis N, Makriyannis A, Malamas MS, Thermos K. Investigating the Effects of Exogenous and Endogenous 2-Arachidonoylglycerol on Retinal CB1 Cannabinoid Receptors and Reactive Microglia in Naive and Diseased Retina. Int J Mol Sci 2023; 24:15689. [PMID: 37958673 PMCID: PMC10650178 DOI: 10.3390/ijms242115689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 10/22/2023] [Accepted: 10/26/2023] [Indexed: 11/15/2023] Open
Abstract
The endocannabinoid system (ECS) is a new target for the development of retinal disease therapeutics, whose pathophysiology involves neurodegeneration and neuroinflammation. The endocannabinoid 2-arachidonoylglycerol (2-AG) affects neurons and microglia by activating CB1/CB2 cannabinoid receptors (Rs). The aim of this study was to investigate the effects of 2-AG on the CB1R expression/downregulation and retinal neurons/reactive microglia, when administered repeatedly (4 d), in three different paradigms. These involved the 2-AG exogenous administration (a) intraperitoneally (i.p.) and (b) topically and (c) by enhancing the 2-AG endogenous levels via the inhibition (AM11920, i.p.) of its metabolic enzymes (MAGL/ABHD6). Sprague Dawley rats were treated as mentioned above in the presence or absence of CB1/CB2R antagonists and the excitatory amino acid, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). Immunohistochemistry, Western blot and a 2-AG level analyses were performed. The 2-AG repeated treatment (i.p.) induced the CB1R downregulation, abolishing its neuroprotective actions. However, 2-AG attenuated the AMPA-induced activation of microglia via the CB2R, as concurred by the AM630 antagonist effect. Topically administered 2-AG was efficacious as a neuroprotectant/antiapoptotic and anti-inflammatory agent. AM11920 increased the 2-AG levels providing neuroprotection against excitotoxicity and reduced microglial activation without affecting the CB1R expression. Our findings show that 2-AG, in the three paradigms studied, displays differential pharmacological profiles in terms of the downregulation of the CB1R and neuroprotection. All treatments, however, attenuated the activation of microglia via the CB2R activation, supporting the anti-inflammatory role of 2-AG in the retina.
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Affiliation(s)
- Sofia Papadogkonaki
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, 71003 Crete, Greece; (S.P.); (D.S.)
| | - Dimitris Spyridakos
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, 71003 Crete, Greece; (S.P.); (D.S.)
| | | | - Nikos Chaniotakis
- Department of Chemistry, University of Crete, Heraklion, 71003 Crete, Greece; (E.L.); (N.C.)
| | - Alexandros Makriyannis
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA; (A.M.); (M.S.M.)
| | - Michael S. Malamas
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA; (A.M.); (M.S.M.)
| | - Kyriaki Thermos
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, 71003 Crete, Greece; (S.P.); (D.S.)
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CB 1R, CB 2R and TRPV1 expression and modulation in in vivo, animal glaucoma models: A systematic review. Biomed Pharmacother 2022; 150:112981. [PMID: 35468582 DOI: 10.1016/j.biopha.2022.112981] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/06/2022] [Accepted: 04/14/2022] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The endocannabinoid system (ECS) is a complex biological regulatory system. Its expression and functionality have been widely investigated in ocular tissues. Recent data have reported its modulation to be valid in determining an ocular hypotensive and a neuroprotective effect in preclinical animal models of glaucoma. AIM This study aimed to explore the available literature on cannabinoid receptor 1 (CB1R), cannabinoid receptor 2 (CB2R), and transient receptor potential vanilloid 1 (TRPV1) expression in the trabecular meshwork (TM), ciliary body (CB), and retina as well as their ocular hypotensive and neuroprotective effects in preclinical, in vivo, animal glaucoma models. MATERIALS AND METHODS The study adhered to both PRISMA and SYRCLE guidelines. Sixty-nine full-length articles were included in the final analysis. RESULTS Preclinical studies indicated a widespread distribution of CB1R, CB2R, and TRPV1 in the TM, CB, and retina, although receptor-, age-, and species-dependent differences were observed. CB1R and CB2R modulation have been shown to exert ocular hypotensive effects in preclinical models via the regulation of inflow and outflow pathways. Retinal cell neuroprotection has been achieved in several experimental models, mediated by agonists and antagonists of CB1R, CB2R, and TRPV1. DISCUSSION Despite the growing body of preclinical data regarding the expression and modulation of ECS in ocular tissues, the mechanisms responsible for the hypotensive and neuroprotective efficacy exerted by this system remain largely elusive. Research on this topic is advocated to further substantiate the hypothesis that the ECS is a new potential therapeutic target in the context of glaucoma.
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Remy I, Schwitzer T, Albuisson É, Schwan R, Krieg J, Bernardin F, Ligier F, Lalanne L, Maillard L, Laprevote V. Impaired P100 among regular cannabis users in response to magnocellular biased visual stimuli. Prog Neuropsychopharmacol Biol Psychiatry 2022; 113:110437. [PMID: 34520807 DOI: 10.1016/j.pnpbp.2021.110437] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 08/30/2021] [Accepted: 09/08/2021] [Indexed: 01/10/2023]
Abstract
Regular cannabis using causes vision impairment by affecting human retinal neurotransmission. However, studies less considered its impact on the subsequent visual cortical processing, key feature for the integration of the visual signal in brain. We aimed at investigating this purpose in regular cannabis users using spatial frequencies and temporal frequencies filtered visual stimuli. We recruited 45 regular cannabis users and 25 age-matched controls. We recorded visual evoked potentials during the projection of low spatial frequency (0.5 cycles/degree) or high spatial frequency gratings (15 cycles/degree), which were presented statically (0 Hz) or dynamically (8 Hz). We analyzed the amplitude, latency, and area under the curve of both P100 and N170, best EEG markers for early visual processing. Data were compared between groups by repeated measures ANCOVA. Results showed a significant decrease in P100 amplitude among regular cannabis users in low spatial frequency (F(1,67) = 4.43; p = 0.04) and in dynamic condition (F(1,67) = 4.35; p = 0.04). Analysis also reported a decrease in P100 area under the curve in regular cannabis users to low spatial frequency (F(1,67) = 4.31; p = 0.04) and in dynamic condition (F(1,67) = 7.65; p < 0.01). No effect was found on P100 latency, N170 amplitude, latency, or area under the curve. We found alteration of P100 responses to low spatial frequency and dynamic stimuli in regular cannabis users. This result could be interpreted as a preferential magnocellular impairment where such deficit could be linked to glutamatergic dysfunction. As mentioned in the literature, visual and electrophysiological anomalies in schizophrenia are related to a magnocellular dysfunction. Further studies are needed to clarify electrophysiological deficits in both populations. CLINICAL TRIALS REGISTRATION: Electrophysiological Study of the Functioning of Magnocellular Visual Pathway in Regular Cannabis Users (CAUSA MAP). [NCT02864680; ID 2013-A00097-38]. https://clinicaltrials.gov/ct2/show/NCT02864680?cond=Cannabis&cntry=FR&draw=2&rank=1.
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Affiliation(s)
- Irving Remy
- Centre Psychothérapique de Nancy, Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Laxou F-54520, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, F-67200, France; BioSerenity - 47, Boulevard de l'Hôpital, ICM-IPEPS, 75013, Paris, France
| | - Thomas Schwitzer
- Centre Psychothérapique de Nancy, Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Laxou F-54520, France; Université de Lorraine, Faculté de Médecine, Vandœuvre-lès-Nancy F-54505, France; Université de Lorraine, IADI, INSERM U1254, Vandœuvre-lès-Nancy, F-54511, France
| | - Éliane Albuisson
- Unité de méthodologie, Gestion des données statistiques, Centre Hospitalier Régional Universitaire de Nancy, DRCI, Département MPI, UMDS, F-54000 Nancy, France; Université de Lorraine, Faculté de Médecine, Département du Grand Est de Recherche en Soins Primaires (DEGERESP), F-54000 Nancy, France; Université de Lorraine, CNRS, Institut Élie-Cartan de Lorraine, F-54000 Nancy, France
| | - Raymund Schwan
- Centre Psychothérapique de Nancy, Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Laxou F-54520, France; Université de Lorraine, Faculté de Médecine, Vandœuvre-lès-Nancy F-54505, France; Université de Lorraine, IADI, INSERM U1254, Vandœuvre-lès-Nancy, F-54511, France
| | - Julien Krieg
- Centre Psychothérapique de Nancy, Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Laxou F-54520, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, F-67200, France
| | - Florent Bernardin
- Centre Psychothérapique de Nancy, Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Laxou F-54520, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, F-67200, France
| | - Fabienne Ligier
- Centre Psychothérapique de Nancy, Pôle Universitaire de Psychiatrie de l'Enfant et de l'Adolescent, Laxou F-54520, France; Université de Lorraine, EA 4360 APEMAC, Equipe MICS, F-54000, France; Université de Lorraine, EA 4432 InterPsy, Equipe PRISME, F-54000, France
| | - Laurence Lalanne
- INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, F-67200, France; Unité de Psychiatrie et d'Addictologie, Fédération de Médecine Translationnelle de Strasbourg, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, F-67200, France
| | - Louis Maillard
- Université de Lorraine, CNRS, CRAN, UMR 7039, F-54500, Nancy, France; Service de Neurologie, Centre Hospitalier Régional Universitaire de Nancy, Nancy F-54000, France
| | - Vincent Laprevote
- Centre Psychothérapique de Nancy, Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Laxou F-54520, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, F-67200, France; Université de Lorraine, Faculté de Médecine, Vandœuvre-lès-Nancy F-54505, France.
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The Vertical and Horizontal Pathways in the Monkey Retina Are Modulated by Typical and Atypical Cannabinoid Receptors. Cells 2021; 10:cells10113160. [PMID: 34831383 PMCID: PMC8622302 DOI: 10.3390/cells10113160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/04/2021] [Accepted: 11/11/2021] [Indexed: 12/11/2022] Open
Abstract
The endocannabinoid (eCB) system has been found in all visual parts of the central ner-vous system and plays a role in the processing of visual information in many species, including monkeys and humans. Using anatomical methods, cannabinoid receptors are present in the monkey retina, particularly in the vertical glutamatergic pathway, and also in the horizontal GABAergic pathway. Modulating the eCB system regulates normal retinal function as demonstrated by electrophysiological recordings. The characterization of the expression patterns of all types of cannabinoid receptors in the retina is progressing, and further research is needed to elucidate their exact role in processing visual information. Typical cannabinoid receptors include G-protein coupled receptor CB1R and CB2R, and atypical cannabinoid receptors include the G-protein coupled receptor 55 (GPR55) and the ion channel transient receptor potential vanilloid 1 (TRPV1). This review focuses on the expression and localization studies carried out in monkeys, but some data on other animal species and humans will also be reported. Furthermore, the role of the endogenous cannabinoid receptors in retinal function will also be presented using intraocular injections of known modulators (agonists and antagonists) on electroretinographic patterns in monkeys. The effects of the natural bioactive lipid lysophosphatidylglucoside and synthetic FAAH inhibitor URB597 on retinal function, will also be described. Finally, the potential of typical and atypical cannabinoid receptor acti-vity regulation in retinal diseases, such as age-related macular degeneration, diabetic retinopathy, glaucoma, and retinitis pigmentosa will be briefly explored.
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The Inhibition of the Degrading Enzyme Fatty Acid Amide Hydrolase Alters the Activity of the Cone System in the Vervet Monkey Retina. Brain Sci 2021; 11:brainsci11111418. [PMID: 34827417 PMCID: PMC8615683 DOI: 10.3390/brainsci11111418] [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: 09/27/2021] [Revised: 10/20/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022] Open
Abstract
Recent studies using full-field electroretinography (ffERG) that triggers a non-specific mass response generated by several retinal sources have attributed an important role for cannabinoid receptors in mediating vision in primates. Specific cone-mediated responses evoked through the photopic flicker ERG appear to be a better way to validate the assumption that endogenous cannabinoids modulate the cone pathway, since FAAH is mainly expressed in the vervet monkey cone photoreceptors. The aim of this study is two-fold: (1) to use the photopic flicker ERG to target the cone pathway specifically, and (2) use URB597 as a selective inhibitor of the endocannabinoid degrading enzyme Fatty Acid Amide Hydrolase (FAAH) to enhance the levels of fatty acid amides, particularly anandamide. We recorded ERGs under four different flicker frequencies (15, 20, 25, and 30 Hz) in light-adapted conditions after intravitreal injections of URB597. Our results show that intravitreal injections of URB597, compared to the vehicle DMSO, increased significantly ffERG amplitudes at 30 Hz, a frequency that solely recruits cone activity. However, at 15 Hz, a frequency that activates both rods and cones, no significant difference was found in the ERG response amplitude. Additionally, we found no differences in implicit times after URB597 injections compared to DMSO vehicle. These results support the role of molecules degraded by FAAH in cone-mediated vision in non-human primates.
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Cannabinoids in Glaucoma Patients: The Never-Ending Story. J Clin Med 2020; 9:jcm9123978. [PMID: 33302608 PMCID: PMC7763320 DOI: 10.3390/jcm9123978] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 11/26/2020] [Accepted: 12/04/2020] [Indexed: 12/18/2022] Open
Abstract
Glaucoma is one of the principal causes of irreversible blindness worldwide. Yet, intraocular pressure (IOP) is the main modifiable risk factor for disease progression. In the never-ending challenge to develop new and effective drugs, several molecules have been tested as anti-glaucoma agents thanks to their pressure-lowering capabilities. Among these molecules, the cannabinoids have been investigated as possible anti-glaucoma drugs since the early 1970s. Cannabinoids are a large class of chemical compounds that exploit their effects by interaction with cannabinoid receptors 1 and 2. These receptors are widely expressed in the human retina where they may influence important functions such as photo-transduction, amacrine cell network maintenance, and IOP regulation. Therefore, in past years several studies have been conducted in order to assess the IOP lowering effects of cannabinoids. PRISMA guidelines have been used to perform a literature search on Pubmed and Scopus aiming to investigate the mechanism of IOP lowering effects and the potential benefits of orally administered, inhaled, topical, and intravenous cannabinoids in the treatment of glaucoma patients.
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Vielma AH, Tapia F, Alcaino A, Fuenzalida M, Schmachtenberg O, Chávez AE. Cannabinoid Signaling Selectively Modulates GABAergic Inhibitory Input to OFF Bipolar Cells in Rat Retina. Invest Ophthalmol Vis Sci 2020; 61:3. [PMID: 32150246 PMCID: PMC7401570 DOI: 10.1167/iovs.61.3.3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose In the mammalian retina, cannabinoid type 1 receptors (CB1Rs) are well-positioned to alter inhibitory synaptic function from amacrine cells and, thus, might influence visual signal processing in the inner retina. However, it is not known if CB1R modulates amacrine cells feedback inhibition at retinal bipolar cell (BC) terminals. Methods Using whole-cell voltage-clamp recordings, we examined the pharmacological effect of CB1R activation and inhibition on spontaneous inhibitory postsynaptic currents (sIPSCs) and glutamate-evoked IPSCs (gIPSCs) from identified OFF BCs in light-adapted rat retinal slices. Results Activation of CB1R with WIN55212-2 selectively increased the frequency of GABAergic, but not glycinergic sIPSC in types 2, 3a, and 3b OFF BCs, and had no effect on inhibitory activity in type 4 OFF BCs. The increase in GABAergic activity was eliminated in axotomized BCs and can be suppressed by blocking CB1R with AM251 or GABAA and GABAρ receptors with SR-95531 and TPMPA, respectively. In all OFF BC types tested, a brief application of glutamate to the outer plexiform layer elicited gIPSCs comprising GABAergic and glycinergic components that were unaffected by CB1R activation. However, blocking CB1R selectively increased GABAergic gIPSCs, supporting a role for endocannabinoid signaling in the regulation of glutamate-evoked GABAergic inhibitory feedback to OFF BCs. Conclusions CB1R activation shape types 2, 3a, and 3b OFF BC responses by selectively regulate GABAergic feedback inhibition at their axon terminals, thus cannabinoid signaling might play an important role in the fine-tuning of visual signal processing in the mammalian inner retina.
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Zhao L, Liao Q, Zhang Y, Tan S, Li S, Ke T. Ischemic Postconditioning Mitigates Retinopathy in Tree Shrews with Diabetic Cerebral Ischemia. J Diabetes Res 2020; 2020:6286571. [PMID: 32104713 PMCID: PMC7037873 DOI: 10.1155/2020/6286571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 01/04/2020] [Accepted: 01/17/2020] [Indexed: 12/25/2022] Open
Abstract
Ischemic postconditioning (PC) is proved to efficiently protect diabetic patients with acute myocardial infarction from ischemia-reperfusion injury. We aimed to explore the protective roles of ischemic PC on diabetic retinopathy in tree shrews with diabetic cerebral ischemia. A diabetic tree shrew model was established through high-fat diet feeding combined with streptozotocin (STZ) injection, while cortical thrombotic cerebral ischemia was induced photochemically. Tree shrews were divided into the normal control group, sham operation group, diabetes mellitus group, diabetes mellitus+cerebral ischemia group, and diabetes mellitus+cerebral ischemia+PC group (in which the tree shrews with diabetic cerebral ischemia were treated with ischemic PC). H&E staining was used to examine the pathological changes in the retina, and immunohistochemistry was performed to determine the retinal expression of VEGF (vascular endothelial growth factor). The modeling resulted in 77% tree shrews with diabetes. Ischemic PC reduced the blood glucose levels in the tree shrews with diabetic cerebral ischemia. Tree shrews with diabetes had thinned retina with disordered structures, and these pathological changes were aggravated after cerebral ischemia. The retinopathy was alleviated after ischemic PC. Retina expression of VEGF was mainly distributed in the ganglion cell layer in tree shrews. Diabetes and cerebral ischemia increased retinal VEGF expression in a step-wise manner, while additional ischemic PC reduced retinal VEGF expression. Therefore, ischemic PC effectively alleviates retinopathy in tree shrews with diabetic cerebral ischemia, and this effect is associated with reduced retinal VEGF expression.
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Affiliation(s)
- Ling Zhao
- Department of Endocrinology, The Second Affiliated Hospital of Kunming Medical University, Yunnan 650101, China
| | - Qiwei Liao
- Department of Cardiology, The Yan-an Affiliated Hospital of Kunming Medical University, Yunnan 650051, China
| | - Yueting Zhang
- Department of Endocrinology, The Second Affiliated Hospital of Kunming Medical University, Yunnan 650101, China
| | - Shufen Tan
- Department of Gynecologic Oncology, The Third Affiliated Hospital of Kunming Medical University, Yunnan 650101, China
| | - Shuqing Li
- Department of Pathophysiology, Kunming Medical University, Yunnan 650050, China
| | - Tingyu Ke
- Department of Endocrinology, The Second Affiliated Hospital of Kunming Medical University, Yunnan 650101, China
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Faiq MA, Wollstein G, Schuman JS, Chan KC. Cholinergic nervous system and glaucoma: From basic science to clinical applications. Prog Retin Eye Res 2019; 72:100767. [PMID: 31242454 PMCID: PMC6739176 DOI: 10.1016/j.preteyeres.2019.06.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/19/2019] [Accepted: 06/21/2019] [Indexed: 02/08/2023]
Abstract
The cholinergic system has a crucial role to play in visual function. Although cholinergic drugs have been a focus of attention as glaucoma medications for reducing eye pressure, little is known about the potential modality for neuronal survival and/or enhancement in visual impairments. Citicoline, a naturally occurring compound and FDA approved dietary supplement, is a nootropic agent that is recently demonstrated to be effective in ameliorating ischemic stroke, traumatic brain injury, Parkinson's disease, Alzheimer's disease, cerebrovascular diseases, memory disorders and attention-deficit/hyperactivity disorder in both humans and animal models. The mechanisms of its action appear to be multifarious including (i) preservation of cardiolipin, sphingomyelin, and arachidonic acid contents of phosphatidylcholine and phosphatidylethanolamine, (ii) restoration of phosphatidylcholine, (iii) stimulation of glutathione synthesis, (iv) lowering glutamate concentrations and preventing glutamate excitotoxicity, (v) rescuing mitochondrial function thereby preventing oxidative damage and onset of neuronal apoptosis, (vi) synthesis of myelin leading to improvement in neuronal membrane integrity, (vii) improving acetylcholine synthesis and thereby reducing the effects of mental stress and (viii) preventing endothelial dysfunction. Such effects have vouched for citicoline as a neuroprotective, neurorestorative and neuroregenerative agent. Retinal ganglion cells are neurons with long myelinated axons which provide a strong rationale for citicoline use in visual pathway disorders. Since glaucoma is a form of neurodegeneration involving retinal ganglion cells, citicoline may help ameliorate glaucomatous damages in multiple facets. Additionally, trans-synaptic degeneration has been identified in humans and experimental models of glaucoma suggesting the cholinergic system as a new brain target for glaucoma management and therapy.
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Affiliation(s)
- Muneeb A Faiq
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Gadi Wollstein
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Joel S Schuman
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Kevin C Chan
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States; Department of Radiology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States; Center for Neural Science, Faculty of Arts and Science, New York University, New York, NY, United States.
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The Endocannabinoid System Is Present in Rod Outer Segments from Retina and Is Modulated by Light. Mol Neurobiol 2019; 56:7284-7295. [PMID: 31016476 DOI: 10.1007/s12035-019-1603-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/10/2019] [Indexed: 10/27/2022]
Abstract
The aim of the present research was to evaluate if the endocannabinoid system (enzymes and receptors) could be modulated by light in rod outer segment (ROS) from bovine retina. First, we analyzed endocannabinoid 2-arachidonoylglycerol (2-AG) metabolism in purified ROS obtained from dark-adapted (DROS) or light-adapted (LROS) retinas. To this end, diacylglycerol lipase (DAGL), monoacylglycerol lipase (MAGL), and lysophosphatidate phosphohydrolase (LPAP) enzymatic activities were analyzed using radioactive substrates. The protein content of these enzymes and of the receptors to which cannabinoids bind was determined by immunoblotting under light stimulus. Our results indicate that whereas DAGL and MAGL activities were stimulated in retinas exposed to light, no changes were observed in LPAP activity. Interestingly, the protein content of the main enzymes involved in 2-AG metabolism, phospholipase C β1 (PLCβ1), and DAGLα (synthesis), and MAGL (hydrolysis), was also modified by light. PLCβ1 content was increased, while that of lipases was decreased. On the other hand, light produced an increase in the cannabinoid receptors CB1 and CB2 and a decrease in GPR55 protein levels. Taken together, our results indicate that the endocannabinoid system (enzymes and receptors) depends on the illumination state of the retina, suggesting that proteins related to phototransduction phenomena could be involved in the effects observed.
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Bouskila J, Palmour RM, Bouchard JF, Ptito M. Retinal structure and function in monkeys with fetal alcohol exposure. Exp Eye Res 2018; 177:55-64. [PMID: 30071214 DOI: 10.1016/j.exer.2018.07.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 07/24/2018] [Accepted: 07/26/2018] [Indexed: 11/16/2022]
Abstract
Exposure to ethanol in utero leads to several brain development disorders including retinal abnormalities whose underlying cellular pathogenesis remains elusive. We recently reported that fetal alcohol exposure (FAE) in vervet monkeys induces anomalies of full-field electroretinogram (ERG) waveforms that suggest premature aging of the retina. The goal of this study is to characterize the anatomo-functional mechanisms underlying the retinal changes observed in fetal alcohol exposed (FAE) monkeys, and age- and sex-matched normals. First, we examined in vivo the fundus of the eyes, measured intraocular pressure (IOP) and assessed cone activity using flicker ERG. Second, we investigated ex vivo, protein expression and anatomical organization of the retina using Western blotting, classical histology and immunohistochemistry. Our results indicated that the fundus of the eyes showed both, increased vascularization (tessellated fundus) and IOP in FAE monkeys. Furthermore, light-adapted flicker responses above 15 Hz were also significantly higher in FAE monkeys. Although there were no obvious changes in the overall anatomy in the FAE retina, Glial Fibrillary Acidic Protein (GFAP, a potent marker of astrocytes) immunoreactivity was increased in the FAE retinal ganglion cell layer indicating a strong astrogliosis. These alterations were present in juvenile (2 years old) monkeys and persist in adults (8 years old). Moreover, using specific cell type markers, no significant modifications in the morphology of the photoreceptors, horizontal cells, bipolar cells, and amacrine cells were observed. Our data indicate that FAE does indeed induce anatomical changes within the retinal ganglion cell layer that are reflected in the increased photosensitivity of the cone photoreceptors.
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Affiliation(s)
- Joseph Bouskila
- Departments of Psychiatry and Human Genetics, McGill University, Montreal, QC, Canada; Behavioral Science Foundations, Saint Kitts and Nevis; School of Optometry, University of Montreal, Montreal, Quebec, Canada.
| | - Roberta M Palmour
- Departments of Psychiatry and Human Genetics, McGill University, Montreal, QC, Canada; Behavioral Science Foundations, Saint Kitts and Nevis
| | | | - Maurice Ptito
- School of Optometry, University of Montreal, Montreal, Quebec, Canada; Department of Nuclear Medicine, University of Southern Denmark, Odense, Denmark
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da Silva Sampaio L, Kubrusly RCC, Colli YP, Trindade PP, Ribeiro-Resende VT, Einicker-Lamas M, Paes-de-Carvalho R, Gardino PF, de Mello FG, De Melo Reis RA. Cannabinoid Receptor Type 1 Expression in the Developing Avian Retina: Morphological and Functional Correlation With the Dopaminergic System. Front Cell Neurosci 2018; 12:58. [PMID: 29662438 PMCID: PMC5890097 DOI: 10.3389/fncel.2018.00058] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 02/19/2018] [Indexed: 01/19/2023] Open
Abstract
The avian retina has been used as a model to study signaling by different neuro- and gliotransmitters. It is unclear how dopaminergic and cannabinoid systems are related in the retina. Here we studied the expression of type 1 and 2 cannabinoid receptors (CB1 and CB2), as well as monoacylglycerol lipase (MAGL), the enzyme that degrades 2-arachidonoylglycerol (2-AG), during retina development. Our data show that CB1 receptor is highly expressed from embryonic day 5 (E5) until post hatched day 7 (PE7), decreasing its levels throughout development. CB1 is densely found in the ganglion cell layer (GCL) and inner plexiform layer (IPL). CB2 receptor was also found from E5 until PE7 with a decrease in its contents from E9 afterwards. CB2 was mainly present in the lamination of the IPL at PE7. MAGL is expressed in all retinal layers, mainly in the IPL and OPL from E9 to PE7 retina. CB1 and CB2 were found both in neurons and glia cells, but MAGL was only expressed in Müller glia. Older retinas (PE7) show CB1 positive cells mainly in the INL and co-expression of CB1 and tyrosine hydroxylase (TH) are shown in a few cells when both systems are mature. CB1 co-localized with TH and was heavily associated to D1 receptor labeling in primary cell cultures. Finally, cyclic AMP (cAMP) was activated by the selective D1 agonist SKF38393, and inhibited when cultures were treated with WIN55, 212–2 (WIN) in a CB1 dependent manner. The results suggest a correlation between the endocannabinoid and dopaminergic systems (DSs) during the avian retina development. Activation of CB1 limits cAMP accumulation via D1 receptor activation and may influence embryological parameters during avian retina differentiation.
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Affiliation(s)
- Luzia da Silva Sampaio
- Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Regina C C Kubrusly
- Laboratório de Neurofarmacologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Brazil
| | - Yolanda P Colli
- Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Priscila P Trindade
- Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Victor T Ribeiro-Resende
- Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcelo Einicker-Lamas
- Laboratório de Biomembranas, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Roberto Paes-de-Carvalho
- Laboratório de Neurobiologia Celular, Programa de Neurociências, Universidade Federal Fluminense, Niterói, Brazil
| | - Patricia F Gardino
- Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fernando G de Mello
- Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ricardo A De Melo Reis
- Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Rapino C, Tortolani D, Scipioni L, Maccarrone M. Neuroprotection by (endo)Cannabinoids in Glaucoma and Retinal Neurodegenerative Diseases. Curr Neuropharmacol 2018; 16:959-970. [PMID: 28738764 PMCID: PMC6120105 DOI: 10.2174/1570159x15666170724104305] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 07/14/2017] [Accepted: 07/21/2017] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Emerging neuroprotective strategies are being explored to preserve the retina from degeneration, that occurs in eye pathologies like glaucoma, diabetic retinopathy, age-related macular degeneration, and retinitis pigmentosa. Incidentally, neuroprotection of retina is a defending mechanism designed to prevent or delay neuronal cell death, and to maintain neural function following an initial insult, thus avoiding loss of vision. METHODS Numerous studies have investigated potential neuroprotective properties of plant-derived phytocannabinoids, as well as of their endogenous counterparts collectively termed endocannabinoids (eCBs), in several degenerative diseases of the retina. eCBs are a group of neuromodulators that, mainly by activating G protein-coupled type-1 and type-2 cannabinoid (CB1 and CB2) receptors, trigger multiple signal transduction cascades that modulate central and peripheral cell functions. A fine balance between biosynthetic and degrading enzymes that control the right concentration of eCBs has been shown to provide neuroprotection in traumatic, ischemic, inflammatory and neurotoxic damage of the brain. RESULTS Since the existence of eCBs and their binding receptors was documented in the retina of numerous species (from fishes to primates), their involvement in the visual processing has been demonstrated, more recently with a focus on retinal neurodegeneration and neuroprotection. CONCLUSION The aim of this review is to present a modern view of the endocannabinoid system, in order to discuss in a better perspective available data from preclinical studies on the use of eCBs as new neuroprotective agents, potentially useful to prevent glaucoma and retinal neurodegenerative diseases.
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Affiliation(s)
- Cinzia Rapino
- Address correspondence to these authors at the Faculty of Veterinary Medicine, University of Teramo, 64100 Teramo, Italy; Tel: +39 0861 266842;, E-mail: and the Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy; Tel: +39 06 225419169;, E-mail:
| | | | | | - Mauro Maccarrone
- Address correspondence to these authors at the Faculty of Veterinary Medicine, University of Teramo, 64100 Teramo, Italy; Tel: +39 0861 266842;, E-mail: and the Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy; Tel: +39 06 225419169;, E-mail:
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Chen Y, Luo X, Liu S, Shen Y. Neuroprotective effect of cannabinoid receptor 1 antagonist in the MNU-induced retinal degeneration model. Exp Eye Res 2017; 167:145-151. [PMID: 29126840 DOI: 10.1016/j.exer.2017.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 11/02/2017] [Accepted: 11/06/2017] [Indexed: 11/16/2022]
Abstract
Endocannabinoid system involves in neuroprotective effects on the central neural system. The cannabinoid receptor 1 (CB1R) is widely expressed in the mouse retina. However, the role of cannabinoid receptors in the retina remains unclear. In this work, we established a photoreceptor degeneration mouse model via N-methyl-N-nitrosourea (MNU) administration to identify the neuroprotective effects of cannabinoid receptors. The MNU-induced retinal degeneration behaves similarly to that in the human retinitis pigmentosa (RP). Administration of the CB1R antagonist SR141716A distinctly recovered the photoreceptor loss, decreased glial reactivity and reduced abnormal vascular complexes in an MNU-induced mouse model. The BC dendrites were shrunk in the MNU-treated retina with eliminated ON-BCs responses and partially diminished OFF-BCs responses in patch-clamp recordings. In the MNU + SR1 group, both the function and structure of ON-BCs recovered. Taken together, our study showed that the inhibition of CB1R can effectively prevent MNU-induced retinal degeneration, suggesting a potential therapeutic effect of the CB1R antagonist SR1 in retinal degeneration diseases.
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Affiliation(s)
- Yuanyuan Chen
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, PR China
| | - Xue Luo
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, PR China
| | - Shiliang Liu
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, PR China
| | - Yin Shen
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, PR China.
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The arguments for and against cannabinoids application in glaucomatous retinopathy. Biomed Pharmacother 2016; 86:620-627. [PMID: 28027538 DOI: 10.1016/j.biopha.2016.11.106] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Revised: 11/21/2016] [Accepted: 11/27/2016] [Indexed: 01/22/2023] Open
Abstract
Glaucoma represents several optic neuropathies leading to irreversible blindness through progressive retinal ganglion cell (RGC) loss. Reduction of intraocular pressure (IOP) is known as the only modifiable factor in the treatment of this disorder. Application of exogenous cannabinoids to lower IOP has attracted attention of scientists as potential agents for the treatment of glaucoma. Accordingly, neuroprotective effect of these agents has been recently described through modulation of endocannabinoid system in the eye. In the present work, pertinent information regarding ocular endocannabinoid system, mechanism of exogenous cannabinoids interaction with the ocular endocannabinoid system to reduce IOP, and neuroprotection property of cannabinoids will be discussed according to current scientific literature. In addition to experimental studies, bioavailability of cannabinoids, clinical surveys, and adverse effects of application of cannabinoids in glaucoma will be reviewed.
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Rodriguez-Sanchez IP, Guindon J, Ruiz M, Tejero ME, Hubbard G, Martinez-de-Villarreal LE, Barrera-Saldaña HA, Dick EJ, Comuzzie AG, Schlabritz-Loutsevitch NE. The endocannabinoid system in the baboon (Papio spp.) as a complex framework for developmental pharmacology. Neurotoxicol Teratol 2016; 58:23-30. [PMID: 27327781 PMCID: PMC5897907 DOI: 10.1016/j.ntt.2016.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 05/19/2016] [Accepted: 06/16/2016] [Indexed: 12/22/2022]
Abstract
INTRODUCTION The consumption of marijuana (exogenous cannabinoid) almost doubled in adults during last decade. Consumption of exogenous cannabinoids interferes with the endogenous cannabinoid (or "endocannabinoid" (eCB)) system (ECS), which comprises N-arachidonylethanolamide (anandamide, AEA), 2-arachidonoyl glycerol (2-AG), endocannabinoid receptors (cannabinoid receptors 1 and 2 (CB1R and CB2R), encoded by CNR1 and CNR2, respectively), and synthesizing/degrading enzymes (FAAH, fatty-acid amide hydrolase; MAGL, monoacylglycerol lipase; DAGL-α, diacylglycerol lipase-alpha). Reports regarding the toxic and therapeutic effects of pharmacological compounds targeting the ECS are sometimes contradictory. This may be caused by the fact that structure of the eCBs varies in the species studied. OBJECTIVES First: to clone and characterize the cDNAs of selected members of ECS in a non-human primate (baboon, Papio spp.), and second: to compare those cDNA sequences to known human structural variants (single nucleotide polymorphisms and haplotypes). MATERIALS AND METHODS Polymerase chain reaction-amplified gene products from baboon tissues were transformed into Escherichia coli. Amplicon-positive clones were sequenced, and the obtained sequences were conceptually translated into amino-acid sequences using the genetic code. RESULTS Among the ECS members, CNR1 was the best conserved gene between humans and baboons. The phenotypes associated with mutations in the untranslated regions of this gene in humans have not been described in baboons. One difference in the structure of CNR2 between humans and baboons was detected in the region with the only known clinically relevant polymorphism in a human receptor. All of the differences in the amino-acid structure of DAGL-α between humans and baboons were located in the hydroxylase domain, close to phosphorylation sites. None of the differences in the amino-acid structure of MAGL observed between baboons and humans were located in the area critical for enzyme function. CONCLUSION The evaluation of the data, obtained in non-human primate model of cannabis-related developmental exposure should take into consideration possible evolutionary-determined species-specific differences in the CB1R expression, CB2R transduction pathway, and FAAH and DAGLα substrate-enzyme interactions.
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Affiliation(s)
- Iram P Rodriguez-Sanchez
- Universidad Autónoma de Nuevo León, Facultad de Medicina, Departamento de Genética, Monterrey, Nuevo León, Mexico
| | - Josee Guindon
- Department of Pharmacology and Neurobiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Marco Ruiz
- Department of Obstetrics and Gynecology, Texas Tech University Health Sciences Center at the Permian Basin, Odessa, TX, USA
| | - M Elizabeth Tejero
- Laboratorio de Nutrigenética y Nutrigenómica, Instituto Nacional de Medicina Genómica (INMEGEN), México, D.F., Mexico
| | - Gene Hubbard
- Department of Pathology, University of Texas at San Antonio, San Antonio, TX, USA
| | | | - Hugo A Barrera-Saldaña
- Universidad Autónoma de Nuevo León, Facultad de Medicina, Departamento de Bioquímica y Medicina Molecular, Monterrey, Nuevo León, Mexico
| | - Edward J Dick
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Anthony G Comuzzie
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
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