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Mondal K, Del Mar NA, Gary AA, Grambergs RC, Yousuf M, Tahia F, Stephenson B, Stephenson DJ, Chalfant CE, Reiner A, Mandal N. Sphingolipid changes in mouse brain and plasma after mild traumatic brain injury at the acute phases. Lipids Health Dis 2024; 23:200. [PMID: 38937745 PMCID: PMC11209960 DOI: 10.1186/s12944-024-02186-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 06/14/2024] [Indexed: 06/29/2024] Open
Abstract
BACKGROUND Traumatic brain injury (TBI) causes neuroinflammation and can lead to long-term neurological dysfunction, even in cases of mild TBI (mTBI). Despite the substantial burden of this disease, the management of TBI is precluded by an incomplete understanding of its cellular mechanisms. Sphingolipids (SPL) and their metabolites have emerged as key orchestrators of biological processes related to tissue injury, neuroinflammation, and inflammation resolution. No study so far has investigated comprehensive sphingolipid profile changes immediately following TBI in animal models or human cases. In this study, sphingolipid metabolite composition was examined during the acute phases in brain tissue and plasma of mice following mTBI. METHODS Wildtype mice were exposed to air-blast-mediated mTBI, with blast exposure set at 50-psi on the left cranium and 0-psi designated as Sham. Sphingolipid profile was analyzed in brain tissue and plasma during the acute phases of 1, 3, and 7 days post-TBI via liquid-chromatography-mass spectrometry. Simultaneously, gene expression of sphingolipid metabolic markers within brain tissue was analyzed using quantitative reverse transcription-polymerase chain reaction. Significance (P-values) was determined by non-parametric t-test (Mann-Whitney test) and by Tukey's correction for multiple comparisons. RESULTS In post-TBI brain tissue, there was a significant elevation of 1) acid sphingomyelinase (aSMase) at 1- and 3-days, 2) neutral sphingomyelinase (nSMase) at 7-days, 3) ceramide-1-phosphate levels at 1 day, and 4) monohexosylceramide (MHC) and sphingosine at 7-days. Among individual species, the study found an increase in C18:0 and a decrease in C24:1 ceramides (Cer) at 1 day; an increase in C20:0 MHC at 3 days; decrease in MHC C18:0 and increase in MHC C24:1, sphingomyelins (SM) C18:0, and C24:0 at 7 days. Moreover, many sphingolipid metabolic genes were elevated at 1 day, followed by a reduction at 3 days and an absence at 7-days post-TBI. In post-TBI plasma, there was 1) a significant reduction in Cer and MHC C22:0, and an increase in MHC C16:0 at 1 day; 2) a very significant increase in long-chain Cer C24:1 accompanied by significant decreases in Cer C24:0 and C22:0 in MHC and SM at 3 days; and 3) a significant increase of C22:0 in all classes of SPL (Cer, MHC and SM) as well as a decrease in Cer C24:1, MHC C24:1 and MHC C24:0 at 7 days. CONCLUSIONS Alterations in sphingolipid metabolite composition, particularly sphingomyelinases and short-chain ceramides, may contribute to the induction and regulation of neuroinflammatory events in the early stages of TBI, suggesting potential targets for novel diagnostic, prognostic, and therapeutic strategies in the future.
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Affiliation(s)
- Koushik Mondal
- Department of Ophthalmology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA
- Molecular Diagnostics Laboratory, Department of Basic & Translational Research, Saroj Gupta Cancer Centre & Research Institute, Kolkata, WB, 700 063, India
| | - Nobel A Del Mar
- Department of Ophthalmology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA
| | - Ashlyn A Gary
- Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Richard C Grambergs
- Department of Ophthalmology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA
| | - Mohd Yousuf
- Department of Ophthalmology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA
| | - Faiza Tahia
- Department of Ophthalmology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA
| | - Benjamin Stephenson
- Departments of Medicine and Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
| | - Daniel J Stephenson
- Departments of Medicine and Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
| | - Charles E Chalfant
- Departments of Medicine and Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
- Research Service, Richmond VA Medical Center, Richmond, VA, 23298, USA
| | - Anton Reiner
- Department of Ophthalmology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA
| | - Nawajes Mandal
- Department of Ophthalmology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA.
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA.
- Department of Pharmaceutical Sciences, College of Pharmacy, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA.
- Memphis VA Medical Center, Memphis, TN, 38104, USA.
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2
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Cui D, Zhang Y, Zhang M. The effect of cannabinoid type 2 receptor agonist on morphine tolerance. IBRO Neurosci Rep 2024; 16:43-50. [PMID: 38145173 PMCID: PMC10733637 DOI: 10.1016/j.ibneur.2023.11.005] [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: 09/05/2023] [Revised: 10/24/2023] [Accepted: 11/14/2023] [Indexed: 12/26/2023] Open
Abstract
Pain highly impacts the quality of life of patients. Morphine is used for pain treatment; however, its side effects, especially morphine tolerance, limit its use in the clinic. The problem of morphine tolerance has plagued health workers and patients for years. Unfortunately, the exact mechanism of morphine tolerance has not been fully clarified. The mechanisms of morphine tolerance that are currently being studied may include μ-opioid receptor (MOR) desensitization and internalization, mitogen-activated protein kinase (MAPK) pathway activation and crosstalk, the effects of microglia and the increase in inflammatory factors. Morphine tolerance can be alleviated by improving the pathophysiological changes that lead to morphine tolerance. Previous studies have shown that a cannabinoid type 2 (CB2) receptor agonist could attenuate morphine tolerance in a variety of animal models. Many studies have shown an interaction between the cannabinoid system and the opioid system. The CB2 receptor may modulate the effect of morphine through a pathway that is common to the MOR, since both receptors are G protein-coupled receptors (GPCRs). This study introduces the potential mechanism of morphine tolerance and the effect of CB2 receptor agonists on reducing morphine tolerance, which can provide new ideas for researchers studying morphine and provide beneficial effects for patients suffering from morphine tolerance.
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Affiliation(s)
- Di Cui
- Department of Anesthesiology, Harbin Medical University Cancer Hospital, Harbin, China
| | - Yuanyuan Zhang
- Department of Anesthesiology, Harbin Medical University Cancer Hospital, Harbin, China
| | - Mingyue Zhang
- Department of Anesthesiology, Harbin Medical University Cancer Hospital, Harbin, China
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3
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Moe A, Rayasam A, Sauber G, Shah RK, Doherty A, Yuan CY, Szabo A, Moore BM, Colonna M, Cui W, Romero J, Zamora AE, Hillard CJ, Drobyski WR. Type 2 cannabinoid receptor expression on microglial cells regulates neuroinflammation during graft-versus-host disease. J Clin Invest 2024; 134:e175205. [PMID: 38662453 PMCID: PMC11142740 DOI: 10.1172/jci175205] [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: 09/07/2023] [Accepted: 04/12/2024] [Indexed: 04/29/2024] Open
Abstract
Neuroinflammation is a recognized complication of immunotherapeutic approaches such as immune checkpoint inhibitor treatment, chimeric antigen receptor therapy, and graft versus host disease (GVHD) occurring after allogeneic hematopoietic stem cell transplantation. While T cells and inflammatory cytokines play a role in this process, the precise interplay between the adaptive and innate arms of the immune system that propagates inflammation in the central nervous system remains incompletely understood. Using a murine model of GVHD, we demonstrate that type 2 cannabinoid receptor (CB2R) signaling plays a critical role in the pathophysiology of neuroinflammation. In these studies, we identify that CB2R expression on microglial cells induces an activated inflammatory phenotype that potentiates the accumulation of donor-derived proinflammatory T cells, regulates chemokine gene regulatory networks, and promotes neuronal cell death. Pharmacological targeting of this receptor with a brain penetrant CB2R inverse agonist/antagonist selectively reduces neuroinflammation without deleteriously affecting systemic GVHD severity. Thus, these findings delineate a therapeutically targetable neuroinflammatory pathway and have implications for the attenuation of neurotoxicity after GVHD and potentially other T cell-based immunotherapeutic approaches.
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Affiliation(s)
| | | | | | | | | | | | - Aniko Szabo
- Division of Biostatistics, Institute of Health and Equity, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Bob M. Moore
- College of Pharmacy, Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University, Saint Louis, Missouri, USA
| | - Weiguo Cui
- Department of Pathology, Northwestern University, Chicago, Illinois, USA
| | - Julian Romero
- Faculty of Experimental Sciences, Francisco de Vitoria University, Madrid, Spain
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4
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Joers V, Murray BC, McLaughlin C, Oliver D, Staley H, Coronado J, Achat-Mendes C, Golshani S, Kelly SD, Goodson M, Lee D, Manfredsson FP, Moore BM, Tansey MG. Modulation of cannabinoid receptor 2 alters neuroinflammation and reduces formation of alpha-synuclein aggregates in a rat model of nigral synucleinopathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.25.554814. [PMID: 38562842 PMCID: PMC10983852 DOI: 10.1101/2023.08.25.554814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Research into the disequilibrium of microglial phenotypes has become an area of intense focus in neurodegenerative disease as a potential mechanism that contributes to chronic neuroinflammation and neuronal loss in Parkinson's disease (PD). There is growing evidence that neuroinflammation accompanies and may promote progression of alpha-synuclein (Asyn)-induced nigral dopaminergic (DA) degeneration. From a therapeutic perspective, development of immunomodulatory strategies that dampen overproduction of pro-inflammatory cytokines from chronically activated immune cells and induce a pro-phagocytic phenotype is expected to promote Asyn removal and protect vulnerable neurons. Cannabinoid receptor-2 (CB2) is highly expressed on activated microglia and peripheral immune cells, is upregulated in the substantia nigra of individuals with PD and in mouse models of nigral degeneration. Furthermore, modulation of CB2 protects against rotenone-induced nigral degeneration; however, CB2 has not been pharmacologically and selectively targeted in an Asyn model of PD. Here, we report that 7 weeks of peripheral administration of CB2 inverse agonist SMM-189 reduced phosphorylated (pSer129) alpha-synuclein in the substantia nigra compared to vehicle treatment. Additionally, SMM-189 delayed Asyn-induced immune cell infiltration into the brain as determined by flow cytometry, increased CD68 protein expression, and elevated wound-healing-immune-mediator gene expression. Additionally, peripheral immune cells increased wound-healing non-classical monocytes and decreased pro-inflammatory classical monocytes. In vitro analysis of RAW264.7 macrophages treated with lipopolysaccharide (LPS) and SMM-189 revealed increased phagocytosis as measured by the uptake of fluorescence of pHrodo E. coli bioparticles. Together, results suggest that targeting CB2 with SMM-189 skews immune cell function toward a phagocytic phenotype and reduces toxic aggregated species of Asyn. Our novel findings demonstrate that CB2 may be a target to modulate inflammatory and immune responses in proteinopathies.
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Affiliation(s)
- Valerie Joers
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, Florida
- Center for Translational Research in Neurodegenerative Disease, University of Florida College of Medicine, Gainesville, Florida
- McKnight Brain Institute, University of Florida, Gainesville, Florida
| | | | | | - Danielle Oliver
- Department of Physiology, Emory University, Atlanta, Georgia
| | - Hannah Staley
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, Florida
- Center for Translational Research in Neurodegenerative Disease, University of Florida College of Medicine, Gainesville, Florida
- McKnight Brain Institute, University of Florida, Gainesville, Florida
| | - Jazmyn Coronado
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, Florida
- Center for Translational Research in Neurodegenerative Disease, University of Florida College of Medicine, Gainesville, Florida
- McKnight Brain Institute, University of Florida, Gainesville, Florida
| | | | - Sanam Golshani
- Department of Physiology, Emory University, Atlanta, Georgia
| | - Sean D Kelly
- Department of Physiology, Emory University, Atlanta, Georgia
| | - Matthew Goodson
- Department of Physiology, Emory University, Atlanta, Georgia
| | - Danica Lee
- Department of Physiology, Emory University, Atlanta, Georgia
| | - Fredric P Manfredsson
- Parkinson's Disease Research Unit, Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, Arizona
| | - Bob M Moore
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Malú Gámez Tansey
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, Florida
- Center for Translational Research in Neurodegenerative Disease, University of Florida College of Medicine, Gainesville, Florida
- McKnight Brain Institute, University of Florida, Gainesville, Florida
- Norman Fixel Institute for Neurological Diseases, University of Florida Health, Gainesville, Florida
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5
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Zhang Q, Zhao Y, Wu J, Zhong W, Huang W, Pan Y. The progress of small molecules against cannabinoid 2 receptor (CB 2R). Bioorg Chem 2024; 144:107075. [PMID: 38218067 DOI: 10.1016/j.bioorg.2023.107075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/03/2023] [Accepted: 12/27/2023] [Indexed: 01/15/2024]
Abstract
The two subtypes of cannabinoid receptors (CBR), namely CB1R and CB2R, belong to the G protein-coupled receptor (GPCR) superfamily and are confirmed as potential therapeutic targets for a variety of diseases such as inflammation, neuropathic pain, and immune-related disorders. Since CB1R is mainly distributed in the central nervous system (CNS), it could produce severe psychiatric adverse reactions and addiction. In contrast, CB2R are predominantly distributed in the peripheral immune system with minimal CNS-related side effects. Therefore, more attention has been devoted to the discovery of CB2R ligands. In view of the favorable profile of CB2R, many high-binding affinity and selectivity CB2R ligands have been developed recently. This paper reviews recent research progress on CB2R ligands, including endogenous CB2R ligands, natural compounds, and novel small molecules, in order to provide a reference for subsequent CB2R ligand development.
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Affiliation(s)
| | - Ying Zhao
- Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Jianan Wu
- Hangzhou Medical College, Hangzhou, Zhejiang, China
| | | | - Wenhai Huang
- Hangzhou Medical College, Hangzhou, Zhejiang, China.
| | - Youlu Pan
- Hangzhou Medical College, Hangzhou, Zhejiang, China.
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6
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Ding L, Patel A, Shankar S, Driscoll N, Zhou C, Rex TS, Vitale F, Gallagher MJ. An Open-Source Mouse Chronic EEG Array System with High-Density MXene-Based Skull Surface Electrodes. eNeuro 2024; 11:ENEURO.0512-22.2023. [PMID: 38388423 PMCID: PMC10884564 DOI: 10.1523/eneuro.0512-22.2023] [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: 12/16/2022] [Revised: 11/12/2023] [Accepted: 12/18/2023] [Indexed: 02/24/2024] Open
Abstract
Electroencephalography (EEG) is an indispensable tool in epilepsy, sleep, and behavioral research. In rodents, EEG recordings are typically performed with metal electrodes that traverse the skull into the epidural space. In addition to requiring major surgery, intracranial EEG is difficult to perform for more than a few electrodes, is time-intensive, and confounds experiments studying traumatic brain injury. Here, we describe an open-source cost-effective refinement of this technique for chronic mouse EEG recording. Our alternative two-channel (EEG2) and sixteen-channel high-density EEG (HdEEG) arrays use electrodes made of the novel, flexible 2D nanomaterial titanium carbide (Ti3C2T x ) MXene. The MXene electrodes are placed on the surface of the intact skull and establish an electrical connection without conductive gel or paste. Fabrication and implantation times of MXene EEG electrodes are significantly shorter than the standard approach, and recorded resting baseline and epileptiform EEG waveforms are similar to those obtained with traditional epidural electrodes. Applying HdEEG to a mild traumatic brain injury (mTBI) model in mice of both sexes revealed that mTBI significantly increased spike-wave discharge (SWD) preictal network connectivity with frequencies of interest in the β-spectral band (12-30 Hz). These findings indicate that the fabrication of MXene electrode arrays is a cost-effective, efficient technology for multichannel EEG recording in mice that obviates the need for skull-penetrating surgery. Moreover, increased preictal β-frequency network connectivity may contribute to the development of early post-mTBI SWDs.
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Affiliation(s)
- Li Ding
- Department of Neurology, Vanderbilt University School of Medicine, Nashville 37232, Tennessee
| | - Aashvi Patel
- Department of Neurology, Vanderbilt University School of Medicine, Nashville 37232, Tennessee
| | - Sneha Shankar
- Departments of Bioengineering and Neurology, Center for Neuroengineering & Therapeutics, University of Pennsylvania, Philadelphia 19104, Pennsylvania
| | - Nicolette Driscoll
- Departments of Bioengineering and Neurology, Center for Neuroengineering & Therapeutics, University of Pennsylvania, Philadelphia 19104, Pennsylvania
| | - Chengwen Zhou
- Department of Neurology, Vanderbilt University School of Medicine, Nashville 37232, Tennessee
| | - Tonia S Rex
- Department of Ophthalmology & Visual Sciences, Vanderbilt University School of Medicine, Nashville 37232, Tennessee
| | - Flavia Vitale
- Departments of Bioengineering and Neurology, Center for Neuroengineering & Therapeutics, University of Pennsylvania, Philadelphia 19104, Pennsylvania
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia 19104, Pennsylvania
| | - Martin J Gallagher
- Department of Neurology, Vanderbilt University School of Medicine, Nashville 37232, Tennessee
- Department of Veteran's Affairs, Tennessee Valley Health System, Nashville 37212, Tennessee
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7
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Moe A, Rayasam A, Sauber G, Shah RK, Yuan CY, Szabo A, Moore BM, Colonna M, Cui W, Romero J, Zamora AE, Hillard CJ, Drobyski WR. MICROGLIAL CELL EXPRESSION OF THE TYPE 2 CANNABINOID RECEPTOR REGULATES IMMUNE-MEDIATED NEUROINFLAMMATION. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.10.552854. [PMID: 37645843 PMCID: PMC10462026 DOI: 10.1101/2023.08.10.552854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Neuroinflammation is a recognized complication of immunotherapeutic approaches such as immune checkpoint inhibitor treatment, chimeric antigen receptor therapy, and graft versus host disease (GVHD) occurring after allogeneic hematopoietic stem cell transplantation. While T cells and inflammatory cytokines play a role in this process, the precise interplay between the adaptive and innate arms of the immune system that propagates inflammation in the central nervous system remains incompletely understood. Using a murine model of GVHD, we demonstrate that type 2 cannabinoid receptor (CB2R) signaling plays a critical role in the pathophysiology of neuroinflammation. In these studies, we identify that CB2R expression on microglial cells induces an activated inflammatory phenotype which potentiates the accumulation of donor-derived proinflammatory T cells, regulates chemokine gene regulatory networks, and promotes neuronal cell death. Pharmacological targeting of this receptor with a brain penetrant CB2R inverse agonist/antagonist selectively reduces neuroinflammation without deleteriously affecting systemic GVHD severity. Thus, these findings delineate a therapeutically targetable neuroinflammatory pathway and has implications for the attenuation of neurotoxicity after GVHD and potentially other T cell-based immunotherapeutic approaches.
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8
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Lins BR, Anyaegbu CC, Hellewell SC, Papini M, McGonigle T, De Prato L, Shales M, Fitzgerald M. Cannabinoids in traumatic brain injury and related neuropathologies: preclinical and clinical research on endogenous, plant-derived, and synthetic compounds. J Neuroinflammation 2023; 20:77. [PMID: 36935484 PMCID: PMC10026409 DOI: 10.1186/s12974-023-02734-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 02/13/2023] [Indexed: 03/21/2023] Open
Abstract
Traumatic brain injury is common, and often results in debilitating consequences. Even mild traumatic brain injury leaves approximately 20% of patients with symptoms that persist for months. Despite great clinical need there are currently no approved pharmaceutical interventions that improve outcomes after traumatic brain injury. Increased understanding of the endocannabinoid system in health and disease has accompanied growing evidence for therapeutic benefits of Cannabis sativa. This has driven research of Cannabis' active chemical constituents (phytocannabinoids), alongside endogenous and synthetic counterparts, collectively known as cannabinoids. Also of therapeutic interest are other Cannabis constituents, such as terpenes. Cannabinoids interact with neurons, microglia, and astrocytes, and exert anti-inflammatory and neuroprotective effects which are highly desirable for the management of traumatic brain injury. In this review, we comprehensively appraised the relevant scientific literature, where major and minor phytocannabinoids, terpenes, synthetic cannabinoids, and endogenous cannabinoids were assessed in TBI, or other neurological conditions with pathology and symptomology relevant to TBI, as well as recent studies in preclinical TBI models and clinical TBI populations.
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Affiliation(s)
- Brittney R Lins
- Curtin Health Innovation Research Institute, Curtin University, Bentley, 6102, Australia.
- Perron Institute for Neurological and Translational Science, Nedlands, 6009, Australia.
| | - Chidozie C Anyaegbu
- Curtin Health Innovation Research Institute, Curtin University, Bentley, 6102, Australia
- Perron Institute for Neurological and Translational Science, Nedlands, 6009, Australia
| | - Sarah C Hellewell
- Curtin Health Innovation Research Institute, Curtin University, Bentley, 6102, Australia
- Perron Institute for Neurological and Translational Science, Nedlands, 6009, Australia
| | - Melissa Papini
- Curtin Health Innovation Research Institute, Curtin University, Bentley, 6102, Australia
- Perron Institute for Neurological and Translational Science, Nedlands, 6009, Australia
| | - Terence McGonigle
- Curtin Health Innovation Research Institute, Curtin University, Bentley, 6102, Australia
| | - Luca De Prato
- MediCann Health Aust Pty Ltd, Osborne Park, 6017, Australia
| | - Matthew Shales
- MediCann Health Aust Pty Ltd, Osborne Park, 6017, Australia
| | - Melinda Fitzgerald
- Curtin Health Innovation Research Institute, Curtin University, Bentley, 6102, Australia
- Perron Institute for Neurological and Translational Science, Nedlands, 6009, Australia
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9
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CB2R activation ameliorates late adolescent chronic alcohol exposure-induced anxiety-like behaviors during withdrawal by preventing morphological changes and suppressing NLRP3 inflammasome activation in prefrontal cortex microglia in mice. Brain Behav Immun 2023; 110:60-79. [PMID: 36754245 DOI: 10.1016/j.bbi.2023.02.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 01/08/2023] [Accepted: 02/03/2023] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Chronic alcohol exposure (CAE) during late adolescence increases the risk of anxiety development. Alcohol-induced prefrontal cortex (PFC) microglial activation, characterized by morphological changes and increased associations with neurons, plays a critical role in the pathogenesis of anxiety. Alcohol exposure increases NLRP3 inflammasome expression, increasing cytokine secretion by activated microglia. Cannabinoid type 2 receptor (CB2R), an essential receptor of the endocannabinoid system, regulates microglial activation and neuroinflammatory reactions. We aimed to investigate the role of CB2R activation in ameliorating late adolescent CAE-induced anxiety-like behaviors and microglial activation in C57BL/6J mice. METHODS Six-week-old C57BL/6J mice were acclimated for 7 days and then were administered alcohol by gavage (4 g/kg, 25 % w/v) for 28 days. The mice were intraperitoneally injected with the specific CB2R agonist AM1241 1 h before alcohol treatment. Anxiety-like behaviors during withdrawal were assessed by open field test and elevated plus maze test 24 h after the last alcohol administration. Microglial activation, microglia-neuron interactions, and CB2R and NLRP3 inflammasome-related molecule expression in the PFC were measured using immunofluorescence, immunohistochemical, qPCR, and Western blotting assays. Microglial morphology was evaluated by Sholl analysis and the cell body-to-total cell size index. Additionally, N9 microglia were activated by LPS in vitro, and the effects of AM1241 on NLRP3 and N9 microglial activation were investigated. RESULTS After CAE, mice exhibited severe anxiety-like behaviors during withdrawal. CAE induced obvious microglia-neuron associations, and increased expression of microglial activation markers, CB2R, and NLRP3 inflammasome-related molecules in the PFC. Microglia also showed marked filament retraction and reduction and cell body enlargement after CAE. AM1241 treatment ameliorated anxiety-like behaviors in CAE model mice, and it prevented microglial morphological changes, reduced microglial activation marker expression, and suppressed the microglial NLRP3 inflammasome activation and proinflammatory cytokine secretion induced by CAE. AM1241 suppressed the LPS-induced increase in NLRP3 inflammasome-related molecules, IL-1β release, and M1 phenotype markers (iNOS and CD86) in N9 cell, which was reversed by CB2R antagonist treatment. CONCLUSIONS CAE caused anxiety-like behaviors in late adolescent mice at least partly by inducing microglial activation and increasing microglia-neuron associations in the PFC. CB2R activation ameliorated these effects by preventing morphological changes and suppressing NLRP3 inflammasome activation in PFC microglia.
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10
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Aychman MM, Goldman DL, Kaplan JS. Cannabidiol's neuroprotective properties and potential treatment of traumatic brain injuries. Front Neurol 2023; 14:1087011. [PMID: 36816569 PMCID: PMC9932048 DOI: 10.3389/fneur.2023.1087011] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/17/2023] [Indexed: 02/05/2023] Open
Abstract
Cannabidiol (CBD) has numerous pharmacological targets that initiate anti-inflammatory, antioxidative, and antiepileptic properties. These neuroprotective benefits have generated interest in CBD's therapeutic potential against the secondary injury cascade from traumatic brain injury (TBI). There are currently no effective broad treatment strategies for combating the damaging mechanisms that follow the primary injury and lead to lasting neurological consequences or death. However, CBD's effects on different neurotransmitter systems, the blood brain barrier, oxidative stress mechanisms, and the inflammatory response provides mechanistic support for CBD's clinical utility in TBI. This review describes the cascades of damage caused by TBI and CBD's neuroprotective mechanisms to counter them. We also present challenges in the clinical treatment of TBI and discuss important future clinical research directions for integrating CBD in treatment protocols. The mechanistic evidence provided by pre-clinical research shows great potential for CBD as a much-needed improvement in the clinical treatment of TBI. Upcoming clinical trials sponsored by major professional sport leagues are the first attempts to test the efficacy of CBD in head injury treatment protocols and highlight the need for further clinical research.
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11
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Spyridakos D, Mastrodimou N, Vemuri K, Ho TC, Nikas SP, Makriyannis A, Thermos K. Blockade of CB1 or Activation of CB2 Cannabinoid Receptors Is Differentially Efficacious in the Treatment of the Early Pathological Events in Streptozotocin-Induced Diabetic Rats. Int J Mol Sci 2022; 24:240. [PMID: 36613692 PMCID: PMC9820336 DOI: 10.3390/ijms24010240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 12/24/2022] Open
Abstract
Oxidative stress, neurodegeneration, neuroinflammation, and vascular leakage are believed to play a key role in the early stage of diabetic retinopathy (ESDR). The aim of this study was to investigate the blockade of cannabinoid receptor 1 (CB1R) and activation of cannabinoid receptor 2 (CB2R) as putative therapeutics for the treatment of the early toxic events in DR. Diabetic rats [streptozotocin (STZ)-induced] were treated topically (20 μL, 10 mg/mL), once daily for fourteen days (early stage DR model), with SR141716 (CB1R antagonist), AM1710 (CB2R agonist), and the dual treatment SR141716/AM1710. Immunohistochemical-histological, ELISA, and Evans-Blue analyses were performed to assess the neuroprotective and vasculoprotective properties of the pharmacological treatments on diabetes-induced retinal toxicity. Activation of CB2R or blockade of CB1R, as well as the dual treatment, attenuated the nitrative stress induced by diabetes. Both single treatments protected neural elements (e.g., RGC axons) and reduced vascular leakage. AM1710 alone reversed all toxic insults. These findings provide new knowledge regarding the differential efficacies of the cannabinoids, when administered topically, in the treatment of ESDR. Cannabinoid neuroprotection of the diabetic retina in ESDR may prove therapeutic in delaying the development of the advanced stage of the disease.
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Affiliation(s)
- Dimitris Spyridakos
- Department of Pharmacology, School of Medicine, University of Crete, 71003 Heraklion, Greece
| | - Niki Mastrodimou
- Department of Pharmacology, School of Medicine, University of Crete, 71003 Heraklion, Greece
| | - Kiran Vemuri
- Center for Drug Discovery, Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
| | - Thanh C. Ho
- Center for Drug Discovery, Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
| | - Spyros P. Nikas
- Center for Drug Discovery, Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
| | - Alexandros Makriyannis
- Center for Drug Discovery, Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
| | - Kyriaki Thermos
- Department of Pharmacology, School of Medicine, University of Crete, 71003 Heraklion, Greece
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12
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Swanson ML, Regner KR, Moore BM, Park F. Cannabinoid Type 2 Receptor Activation Reduces the Progression of Kidney Fibrosis Using a Mouse Model of Unilateral Ureteral Obstruction. Cannabis Cannabinoid Res 2022; 7:790-803. [PMID: 35196117 DOI: 10.1089/can.2021.0127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Background: Kidney fibrosis is a hallmark consequence of all forms of chronic kidney disease with few available treatment modalities. Material and Methods: In this study, we performed the unilateral ureteral obstruction (UUO) procedure to investigate the effects of a selective cannabinoid type 2 (CB2) agonist receptor, SMM-295, as a nephroprotective therapy. Results: SMM-295 was demonstrated to exhibit 50-fold selectivity over the cannabinoid type 1 (CB1) receptor with an EC50 ∼2 nM. Four other off-targets were identified in the safety panel, but only at the highest concentration (5 mM) tested in the assay demonstrating the relative selectivity and safety of our compound. Administration of SMM-295 (12 mg/kg IP daily) in UUO mice led to a significant decrease of 33% in tubular damage compared to the vehicle-treated UUO mice after 7 days. Consistent with these findings, there was a significant decrease in α-smooth muscle actin and fibronectin, which are markers of tubulointerstitial fibrosis, as determined by Western blot analysis. DNA damage as detected by a classic marker, γ-H2AX, was significantly reduced by 50% in the SMM-295 treatment group compared to vehicle treatment. Genetic knockout of CB2 or administration of a CB2 inverse agonist did not exhibit any beneficial effect on tubulointerstitial fibrosis or kidney tubule injury. Conclusions: In conclusion, our study provides new evidence that SMM-295 can therapeutically target the CB2 receptor with few, if any, physiological off-target sites to reduce kidney tissue damage and slow the fibrotic progression in a mouse model of kidney fibrosis.
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Affiliation(s)
- Mallory L Swanson
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Kevin R Regner
- Division of Nephrology, Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Bob M Moore
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Frank Park
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
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13
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Honig MG, Del Mar NA, Moore BM, Reiner A. Raloxifene Mitigates Emotional Deficits after Mild Traumatic Brain Injury in Mice. Neurotrauma Rep 2022; 3:534-544. [DOI: 10.1089/neur.2022.0052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Affiliation(s)
- Marcia G. Honig
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Nobel A. Del Mar
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Bob M. Moore
- Department of Pharmaceutical Sciences, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Anton Reiner
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
- Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
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14
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Rasiah PK, Jha KA, Gentry J, Del Mar NA, Townsend T, Torgbe KE, Reiner A, Gangaraju R. A Long-Term Safety and Efficacy Report on Intravitreal Delivery of Adipose Stem Cells and Secretome on Visual Deficits After Traumatic Brain Injury. Transl Vis Sci Technol 2022; 11:1. [PMID: 36180031 PMCID: PMC9547363 DOI: 10.1167/tvst.11.10.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 08/30/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose We compared intravitreal injection of human adipose stem cell concentrated conditioned media (ASC-CCM) to injection of live ASCs for their long-term safety and effectiveness against the visual deficits of mild traumatic brain injury (mTBI). Methods We first tested different intravitreal ASC doses for safety. Other C57BL/6 mice then received focal cranial blast mTBI and were injected with the safe ASC dose (1000 cells/eye), ASC-CCM (∼200 ng protein/eye), or saline solution. At five and 10 months after blast injury, visual, molecular, and histological assessments evaluated treatment efficacy. Histological evaluation of eyes and other organs at 10 months after blast injury assessed safety. Results Human ASCs at 1000 cells/eye were found to be safe, with >10,000 cells causing retinal damage. Blast-injured mice showed significant vision deficits compared to sham blast mice up to 10 months. Blast mice receiving ASC or ASC-CCM showed improved vision at five months but marginal effects at 10 months, correlated with changes in glial fibrillary acidic protein and proinflammatory gene expression in retina. Immunostaining for human IgG failed to detect ASCs in retina. Peripheral organs examined histologically at 10 months after blast injury were normal. Conclusions Intravitreal injection of ASCs or ASC-CCM is safe and effective against the visual deficits of mTBI. Considering the unimproved glial response and the risk of retinal damage with live cells, our studies suggest that ASC-CCM has better safety and effectiveness than live cells for the treatment of visual dysfunction in mTBI. Translational Relevance This study demonstrates the safety and efficacy of mesenchymal stem cell-based therapeutics, supporting them for phase 1 clinical studies.
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Affiliation(s)
- Pratheepa Kumari Rasiah
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Kumar Abhiram Jha
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Jordy Gentry
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Nobel A. Del Mar
- Department of Anatomy & Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Tanisha Townsend
- Department of Pathology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Kwame E. Torgbe
- Department of Pathology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Anton Reiner
- Department of Anatomy & Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Rajashekhar Gangaraju
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Anatomy & Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
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15
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Honig MG, Del Mar NA, Henderson DL, O'Neal D, Yammanur M, Cox R, Li C, Perry AM, Moore BM, Reiner A. Raloxifene, a cannabinoid type-2 receptor inverse agonist, mitigates visual deficits and pathology and modulates microglia after ocular blast. Exp Eye Res 2022; 218:108966. [PMID: 35143834 DOI: 10.1016/j.exer.2022.108966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/04/2022] [Accepted: 01/24/2022] [Indexed: 11/19/2022]
Abstract
Visual deficits after ocular blast injury (OBI) are common, but pharmacological approaches to improve long-term outcomes have not been identified. Blast forces frequently damage the retina and optic nerves, and work on experimental animals has shown the pro-inflammatory actions of microglia can further exacerbate such injuries. Cannabinoid type-2 receptor (CB2) inverse agonists specifically target activated microglia, biasing them away from the harmful pro-inflammatory M1 state toward the helpful reparative M2 state. We previously found that treating mice with CB2 inverse agonists after traumatic brain injury, produced by either focal cranial air blast or dorsal cranial impact, greatly attenuated the visual deficits and pathology that otherwise resulted. Here we examined the consequences of single and repeat OBI and the benefit provided by raloxifene, an FDA-approved estrogen receptor drug that possesses noteworthy CB2 inverse agonism. After single OBI, although the amplitudes of the A- and B-waves of the electroretinogram and pupil light response appeared to be normal, the mice showed hints of deficits in contrast sensitivity and visual acuity, a trend toward optic nerve axon loss, and significantly increased light aversion, which were reversed by 2 weeks of daily treatment with raloxifene. Mice subjected to repeat OBI (5 blasts spaced 1 min apart), exhibited more severe visual deficits, including decreases in contrast sensitivity, visual acuity, the amplitudes of the A- and B-waves of the electroretinogram, light aversion, and resting pupil diameter (i.e. hyperconstriction), accompanied by the loss of photoreceptor cells and optic nerve axons, nearly all of which were mitigated by raloxifene. Interestingly, optic nerve axon abundance was strongly correlated with contrast sensitivity and visual acuity across all groups of experimental mice in the repeat OBI study, suggesting optic nerve axon loss with rOBI and its attenuation with raloxifene are associated with the extent of these two deficits while photoreceptor abundance was highly correlated with A-wave amplitude and resting pupil size, suggesting a prominent role for photoreceptors in these two deficits. Quantitative PCR (qPCR) showed levels of M1-type microglial markers (e.g. iNOS, IL1β, TNFα, and CD32) in retina, optic nerve, and thalamus were increased 3 days after repeat OBI. With raloxifene treatment, the overall expression of M1 markers was more similar to that in sham mice. Raloxifene treatment was also associated with the elevation of IL10 transcripts in all three tissues compared to repeat OBI alone, but the results for the three other M2 microglial markers we examined were more varied. Taken together, the qPCR results suggest that raloxifene benefit for visual function and pathology was associated with a lessening of the pro-inflammatory actions of microglia. The benefit we find for raloxifene following OBI provides a strong basis for phase-2 efficacy testing in human clinical trials for treating ocular injury.
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Affiliation(s)
- Marcia G Honig
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Nobel A Del Mar
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Desmond L Henderson
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Dylan O'Neal
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Meghna Yammanur
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Rachel Cox
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Chunyan Li
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Aaron M Perry
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Bob M Moore
- Department of Pharmaceutical Sciences, The University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Anton Reiner
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA; Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, TN, 38163, USA.
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16
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Jha KA, Rasiah PK, Gentry J, Del Mar NA, Kumar R, Adebiyi A, Reiner A, Gangaraju R. Mesenchymal stem cell secretome protects against oxidative stress-induced ocular blast visual pathologies. Exp Eye Res 2022; 215:108930. [PMID: 35016886 DOI: 10.1016/j.exer.2022.108930] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 12/16/2021] [Accepted: 01/04/2022] [Indexed: 12/20/2022]
Abstract
Visual deficits are a common concern among subjects with head trauma. Stem cell therapies have gained recent attention in treating visual deficits following head trauma. Previously, we have shown that adipose-derived stem cell (ASC) concentrated conditioned medium (ASC-CCM), when delivered via an intravitreal route, yielded a significant improvement in vision accompanied by a decrease in retinal neuroinflammation in a focal cranial blast model that indirectly injures the retina. The purpose of the current study is to extend our previous studies to a direct ocular blast injury model to further establish the preclinical efficacy of ASC-CCM. Adult C57BL/6J mice were subjected to repetitive ocular blast injury (rOBI) of 25 psi to the left eye, followed by intravitreal delivery of ASC-CCM (∼200 ng protein/2 μl) or saline within 2-3 h. Visual function and histological changes were measured 4 weeks after injury and treatment. In vitro, Müller cells were used to evaluate the antioxidant effect of ASC-CCM. Visual acuity, contrast sensitivity, and b-wave amplitudes in rOBI mice receiving saline were significantly decreased compared with age-matched sham blast mice. Immunohistological analyses demonstrated a significant increase in glial fibrillary acidic protein (a retinal injury marker) in Müller cell processes, DNA/RNA damage, and nitrotyrosine (indicative of oxidative stress) in the retina, while qPCR analysis revealed a >2-fold increase in pro-inflammatory cytokines (TNF-α, ICAM1, and Ccl2) in the retina, as well as markers for microglia/macrophage activation (IL-1β and CD86). Remarkably, rOBI mice that received ASC-CCM demonstrated a significant improvement in visual function compared to saline-treated rOBI mice, with visual acuity, contrast sensitivity, and b-wave amplitudes that were not different from those in sham mice. This improvement in visual function also was associated with a significant reduction in retinal GFAP, neuroinflammation markers, and oxidative stress compared to saline-treated rOBI mice. In vitro, Müller cells exposed to oxidative stress via increasing doses of hydrogen peroxide demonstrated decreased viability, increased GFAP mRNA expression, and reduced activity for the antioxidant catalase. On the other hand, oxidatively stressed Müller cells pre-incubated with ASC-CCM showed normalized GFAP, viability, and catalase activity. In conclusion, our study demonstrates that a single intravitreal injection of ASC-CCM in the rOBI can significantly rescue retinal injury and provide significant restoration of visual function. Our in vitro studies suggest that the antioxidant catalase may play a major role in the protective effects of ASC-CCM, uncovering yet another aspect of the multifaceted benefits of ASC secretome therapies in neurotrauma.
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Affiliation(s)
- Kumar Abhiram Jha
- Department of Ophthalmology, University of Tennessee Health Science Center, 930 Madison Ave, Suite 769, Memphis, TN, 38163, USA.
| | - Pratheepa Kumari Rasiah
- Department of Ophthalmology, University of Tennessee Health Science Center, 930 Madison Ave, Suite 769, Memphis, TN, 38163, USA.
| | - Jordy Gentry
- Department of Ophthalmology, University of Tennessee Health Science Center, 930 Madison Ave, Suite 769, Memphis, TN, 38163, USA.
| | - Nobel A Del Mar
- Department of Anatomy & Neurobiology, University of Tennessee Health Science Center, 317 Wittenborg Building, 875 Monroe Avenue, Memphis, TN, 38163, USA.
| | - Ravi Kumar
- Department of Physiology, University of Tennessee Health Science Center, 956 Court Avenue, Coleman Building, Suite C211, Memphis, TN, 38163, USA.
| | - Adebowale Adebiyi
- Department of Physiology, University of Tennessee Health Science Center, 956 Court Avenue, Coleman Building, Suite C211, Memphis, TN, 38163, USA.
| | - Anton Reiner
- Department of Anatomy & Neurobiology, University of Tennessee Health Science Center, 522 Wittenborg Building, 875 Monroe Avenue, Memphis, TN, 38163, USA.
| | - Rajashekhar Gangaraju
- Department of Ophthalmology, Anatomy & Neurobiology, Neuroscience Institute, University of Tennessee Health Science Center, 930 Madison Ave, Suite 768, Memphis, TN, 38163, USA.
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17
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The Endocannabinoid System in Glial Cells and Their Profitable Interactions to Treat Epilepsy: Evidence from Animal Models. Int J Mol Sci 2021; 22:ijms222413231. [PMID: 34948035 PMCID: PMC8709154 DOI: 10.3390/ijms222413231] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 12/11/2022] Open
Abstract
Epilepsy is one of the most common neurological conditions. Yearly, five million people are diagnosed with epileptic-related disorders. The neuroprotective and therapeutic effect of (endo)cannabinoid compounds has been extensively investigated in several models of epilepsy. Therefore, the study of specific cell-type-dependent mechanisms underlying cannabinoid effects is crucial to understanding epileptic disorders. It is estimated that about 100 billion neurons and a roughly equal number of glial cells co-exist in the human brain. The glial population is in charge of neuronal viability, and therefore, their participation in brain pathophysiology is crucial. Furthermore, glial malfunctioning occurs in a wide range of neurological disorders. However, little is known about the impact of the endocannabinoid system (ECS) regulation over glial cells, even less in pathological conditions such as epilepsy. In this review, we aim to compile the existing knowledge on the role of the ECS in different cell types, with a particular emphasis on glial cells and their impact on epilepsy. Thus, we propose that glial cells could be a novel target for cannabinoid agents for treating the etiology of epilepsy and managing seizure-like disorders.
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18
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Honig MG, Del Mar NA, Henderson DL, O'Neal D, Doty JB, Cox R, Li C, Perry AM, Moore BM, Reiner A. Raloxifene Modulates Microglia and Rescues Visual Deficits and Pathology After Impact Traumatic Brain Injury. Front Neurosci 2021; 15:701317. [PMID: 34776838 PMCID: PMC8585747 DOI: 10.3389/fnins.2021.701317] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 09/07/2021] [Indexed: 11/29/2022] Open
Abstract
Mild traumatic brain injury (TBI) involves widespread axonal injury and activation of microglia, which initiates secondary processes that worsen the TBI outcome. The upregulation of cannabinoid type-2 receptors (CB2) when microglia become activated allows CB2-binding drugs to selectively target microglia. CB2 inverse agonists modulate activated microglia by shifting them away from the harmful pro-inflammatory M1 state toward the helpful reparative M2 state and thus can stem secondary injury cascades. We previously found that treatment with the CB2 inverse agonist SMM-189 after mild TBI in mice produced by focal cranial blast rescues visual deficits and the optic nerve axon loss that would otherwise result. We have further shown that raloxifene, which is Food and Drug Administration (FDA)-approved as an estrogen receptor modulator to treat osteoporosis, but also possesses CB2 inverse agonism, yields similar benefit in this TBI model through its modulation of microglia. As many different traumatic events produce TBI in humans, it is widely acknowledged that diverse animal models must be used in evaluating possible therapies. Here we examine the consequences of TBI created by blunt impact to the mouse head for visual function and associated pathologies and assess raloxifene benefit. We found that mice subjected to impact TBI exhibited decreases in contrast sensitivity and the B-wave of the electroretinogram, increases in light aversion and resting pupil diameter, and optic nerve axon loss, which were rescued by daily injection of raloxifene at 5 or 10 mg/ml for 2 weeks. Raloxifene treatment was associated with reduced M1 activation and/or enhanced M2 activation in retina, optic nerve, and optic tract after impact TBI. Our results suggest that the higher raloxifene dose, in particular, may be therapeutic for the optic nerve by enhancing the phagocytosis of axonal debris that would otherwise promote inflammation, thereby salvaging less damaged axons. Our current work, together with our prior studies, shows that microglial activation drives secondary injury processes after both impact and cranial blast TBI and raloxifene mitigates microglial activation and visual system injury in both cases. The results thus provide a strong basis for phase 2 human clinical trials evaluating raloxifene as a TBI therapy.
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Affiliation(s)
- Marcia G Honig
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Nobel A Del Mar
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Desmond L Henderson
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Dylan O'Neal
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - John B Doty
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Rachel Cox
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Chunyan Li
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Aaron M Perry
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Bob M Moore
- Department of Pharmaceutical Sciences, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Anton Reiner
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States.,Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, TN, United States
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19
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Mondal K, Takahashi H, Cole J, Del Mar NA, Li C, Stephenson DJ, Allegood J, Cowart LA, Chalfant CE, Reiner A, Mandal N. Systemic Elevation of n-3 Polyunsaturated Fatty Acids (n-3-PUFA) Is Associated with Protection against Visual, Motor, and Emotional Deficits in Mice following Closed-Head Mild Traumatic Brain Injury. Mol Neurobiol 2021; 58:5564-5580. [PMID: 34365584 DOI: 10.1007/s12035-021-02501-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 07/17/2021] [Indexed: 12/30/2022]
Abstract
Traumatic brain injury (TBI) causes neuroinflammation and neurodegeneration leading to various pathological complications such as motor and sensory (visual) deficits, cognitive impairment, and depression. N-3 polyunsaturated fatty acid (n-3 PUFA) containing lipids are known to be anti-inflammatory, whereas the sphingolipid, ceramide (Cer), is an inducer of neuroinflammation and degeneration. Using Fat1+-transgenic mice that contain elevated levels of systemic n-3 PUFA, we tested whether they are resistant to mild TBI-mediated sensory-motor and emotional deficits by subjecting Fat1-transgenic mice and their WT littermates to focal cranial air blast (50 psi) or sham blast (0 psi, control). We observed that visual function in WT mice was reduced significantly following TBI but not in Fat1+-blast animals. We also found Fat1+-blast mice were resistant to the decline in motor functions, depression, and fear-producing effects of blast, as well as the reduction in the area of oculomotor nucleus and increase in activated microglia in the optic tract in brain sections seen following blast in WT mice. Lipid and gene expression analyses confirmed an elevated level of the n-3 PUFA eicosapentaenoic acid (EPA) in the plasma and brain, blocking of TBI-mediated increase of Cer in the brain, and decrease in TBI-mediated induction of Cer biosynthetic and inflammatory gene expression in the brain of the Fat1+ mice. Our results demonstrate that suppression of ceramide biosynthesis and inflammatory factors in Fat1+-transgenic mice is associated with significant protection against the visual, motor, and emotional deficits caused by mild TBI. This study suggests that n-3 PUFA (especially, EPA) has a promising therapeutic role in preventing neurodegeneration after TBI.
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Affiliation(s)
- Koushik Mondal
- Department of Ophthalmology, The University of Tennessee Health Science Centre, TN, 38163, Memphis, USA
| | - Haruka Takahashi
- Department of Ophthalmology, The University of Tennessee Health Science Centre, TN, 38163, Memphis, USA.,Department of Animal Science, Iwate University, Morioka, Japan
| | - Jerome Cole
- Department of Ophthalmology, The University of Tennessee Health Science Centre, TN, 38163, Memphis, USA
| | - Nobel A Del Mar
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Centre, TN, 38163, Memphis, USA
| | - Chunyan Li
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Centre, TN, 38163, Memphis, USA
| | - Daniel J Stephenson
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL, 33620, USA
| | - Jeremy Allegood
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23219, USA
| | - L Ashley Cowart
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23219, USA.,Hunter Holmes McGuire VA Medical Center, Richmond, VA, 23249, USA
| | - Charles E Chalfant
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL, 33620, USA.,The Moffitt Cancer Center, Tampa, FL, 33620, USA.,Research Service, James A. Haley Veterans Hospital, Tampa, FL, 33612, USA
| | - Anton Reiner
- Department of Ophthalmology, The University of Tennessee Health Science Centre, TN, 38163, Memphis, USA.,Department of Anatomy and Neurobiology, The University of Tennessee Health Science Centre, TN, 38163, Memphis, USA
| | - Nawajes Mandal
- Department of Ophthalmology, The University of Tennessee Health Science Centre, TN, 38163, Memphis, USA. .,Department of Anatomy and Neurobiology, The University of Tennessee Health Science Centre, TN, 38163, Memphis, USA. .,Department of Pharmaceutical Sciences, College of Pharmacy, The University of Tennessee Health Science Centre, TN, 38163, Memphis, USA. .,Memphis VA Medical Center, Memphis, TN, 38104, USA.
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20
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Dependence of visual and cognitive outcomes on animal holder configuration in a rodent model of blast overpressure exposure. Vision Res 2021; 188:162-173. [PMID: 34333201 DOI: 10.1016/j.visres.2021.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 05/24/2021] [Accepted: 07/14/2021] [Indexed: 02/04/2023]
Abstract
Blast-induced traumatic brain injury is the signature injury of modern military conflicts. To more fully understand the effects of blast exposure, we placed rats in different holder configurations, exposed them to blast overpressure, and assessed the degree of eye and brain injury. Anesthetized Long-Evans rats received blast exposures directed at the head (63 kPa, 195 dB-SPL) in either an "open holder" (head and neck exposed; n = 7), or an "enclosed holder" (window for blast exposure to eye; n = 15) and were compared to non-blast exposed (control) rats (n = 22). Outcomes included optomotor response (OMR), electroretinography (ERG), and spectral domain optical coherence tomography (SD-OCT) at 2, 4, and 6 months post-blast, and cognitive function (Y-maze) at 3 months. Spatial frequency and contrast sensitivity were reduced in ipsilateral blast-exposed eyes in both holders (p < 0.01), while contralateral eyes showed greater deficits with the enclosed holder (p < 0.05). Thinner retinas (p < 0.001) and reduced ERG a- and b- wave amplitudes (p < 0.05) were observed for both ipsilateral and contralateral eyes with the enclosed, but not the open, holder. Rats in the open holder showed cognitive deficits compared to rats in the enclosed holder (p < 0.05). Overall, the animal holder configuration used in blast exposure studies can significantly affect outcomes. Enclosed holders may cause secondary damage to the contralateral eye by concussive injury or blast wave reflection off the holder wall. Open holders may damage the brain via rapid head movement (contrecoup injury). These results highlight additional factors to be considered when evaluating patients with blast exposure or developing models of blast injury.
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Axonopathy precedes cell death in ocular damage mediated by blast exposure. Sci Rep 2021; 11:11774. [PMID: 34083587 PMCID: PMC8175471 DOI: 10.1038/s41598-021-90412-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 05/04/2021] [Indexed: 12/13/2022] Open
Abstract
Traumatic brain injuries (TBI) of varied types are common across all populations and can cause visual problems. For military personnel in combat settings, injuries from blast exposures (bTBI) are prevalent and arise from a myriad of different situations. To model these diverse conditions, we are one of several groups modeling bTBI using mice in varying ways. Here, we report a refined analysis of retinal ganglion cell (RGC) damage in male C57BL/6J mice exposed to a blast-wave in an enclosed chamber. Ganglion cell layer thickness, RGC density (BRN3A and RBPMS immunoreactivity), cellular density of ganglion cell layer (hematoxylin and eosin staining), and axon numbers (paraphenylenediamine staining) were quantified at timepoints ranging from 1 to 17-weeks. RNA sequencing was performed at 1-week and 5-weeks post-injury. Earliest indices of damage, evident by 1-week post-injury, are a loss of RGC marker expression, damage to RGC axons, and increase in glial markers expression. Blast exposure caused a loss of RGC somas and axons—with greatest loss occurring by 5-weeks post-injury. While indices of glial involvement are prominent early, they quickly subside as RGCs are lost. The finding that axonopathy precedes soma loss resembles pathology observed in mouse models of glaucoma, suggesting similar mechanisms.
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22
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Cannabinoid receptor type 2 ligands: an analysis of granted patents since 2010. Pharm Pat Anal 2021; 10:111-163. [DOI: 10.4155/ppa-2021-0002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The G-protein-coupled cannabinoid receptor type 2 (CB2R) is a key element of the endocannabinoid (EC) system. EC/CB2R signaling has significant therapeutic potential in major pathologies affecting humans such as allergies, neurodegenerative disorders, inflammation or ocular diseases. CB2R agonism exerts anti-inflammatory and tissue protective effects in preclinical animal models of cardiovascular, gastrointestinal, liver, kidney, lung and neurodegenerative disorders. Existing ligands can be subdivided into endocannabinoids, cannabinoid-like and synthetic CB2R ligands that possess various degrees of potency on and selectivity against the cannabinoid receptor type 1. This review is an account of granted CB2R ligand patents from 2010 up to the present, which were surveyed using Derwent Innovation®.
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Evans LP, Roghair AM, Gilkes NJ, Bassuk AG. Visual Outcomes in Experimental Rodent Models of Blast-Mediated Traumatic Brain Injury. Front Mol Neurosci 2021; 14:659576. [PMID: 33935648 PMCID: PMC8081965 DOI: 10.3389/fnmol.2021.659576] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 03/18/2021] [Indexed: 11/24/2022] Open
Abstract
Blast-mediated traumatic brain injuries (bTBI) cause long-lasting physical, cognitive, and psychological disorders, including persistent visual impairment. No known therapies are currently utilized in humans to lessen the lingering and often serious symptoms. With TBI mortality decreasing due to advancements in medical and protective technologies, there is growing interest in understanding the pathology of visual dysfunction after bTBI. However, this is complicated by numerous variables, e.g., injury location, severity, and head and body shielding. This review summarizes the visual outcomes observed by various, current experimental rodent models of bTBI, and identifies data showing that bTBI activates inflammatory and apoptotic signaling leading to visual dysfunction. Pharmacologic treatments blocking inflammation and cell death pathways reported to alleviate visual deficits in post-bTBI animal models are discussed. Notably, techniques for assessing bTBI outcomes across exposure paradigms differed widely, so we urge future studies to compare multiple models of blast injury, to allow data to be directly compared.
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Affiliation(s)
- Lucy P. Evans
- Department of Pediatrics, University of Iowa, Iowa City, IA, United States
- Medical Scientist Training Program, University of Iowa, Iowa City, IA, United States
| | - Ariel M. Roghair
- Department of Pediatrics, University of Iowa, Iowa City, IA, United States
| | - Noah J. Gilkes
- Department of Pediatrics, University of Iowa, Iowa City, IA, United States
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24
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Alghamdi SS, Mustafa SM, Moore Ii BM. Synthesis and biological evaluation of a ring analogs of the selective CB2 inverse agonist SMM-189. Bioorg Med Chem 2021; 33:116035. [PMID: 33550084 DOI: 10.1016/j.bmc.2021.116035] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/14/2021] [Accepted: 01/16/2021] [Indexed: 12/23/2022]
Abstract
Microglia are the principle cell type driving sustained neuroinflammation in neurodegenerative diseases such as Alzheimer's, Parkinson's, and Multiple Sclerosis. Interestingly, microglia locked into a chronic M1 pro-inflammatory phenotype significantly up-regulate the cannabinoid receptor 2 (CB2) expression. Our approach to exploiting CB2 as a therapeutic target in neuroinflammatory diseases focuses on the development of selective CB2 inverse agonists to shift microglia bias to a M2 pro-wound healing phenotype. Herein we report work designed to refine the structure activity relationship of the 2,6-dihydroxy-biphenyl-aryl-methanone CB2 inverse agonist scaffold. A series of analogs of our lead compound SMM-189 were synthesized and measured for affinity/selectivity, potency, and efficacy in regulating cAMP production and β-arrestin recruitment. In this series compound 40 demonstrated a significant increase in potency and efficacy for cAMP stimulation compared to SMM-189. Akin to our lead SMM-189, this compound was highly efficacious in biasing microglia to an M2 pro-wound healing phenotype in LPS stimulated cell lines. These results advance our understanding of the structure-activity relationship of the 2,6-dihydroxy-biphenyl-aryl-methanone scaffold and provide further support for regulating microglia activation using CB2 inverse agonists.
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Affiliation(s)
- Sahar S Alghamdi
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Suni M Mustafa
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Bob M Moore Ii
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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Khan RS, Ross AG, Aravand P, Dine K, Selzer EB, Shindler KS. RGC and Vision Loss From Traumatic Optic Neuropathy Induced by Repetitive Closed Head Trauma Is Dependent on Timing and Force of Impact. Transl Vis Sci Technol 2021; 10:8. [PMID: 33505775 PMCID: PMC7794277 DOI: 10.1167/tvst.10.1.8] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 12/09/2020] [Indexed: 12/24/2022] Open
Abstract
Purpose Traumatic optic neuropathy (TON) is often caused by blunt head trauma and has no currently effective treatment. Common animal models of TON induced by surgical crush injury are plagued by variability and do not mimic typical mechanisms of TON injury. Traumatic head impact models have recently shown evidence of TON, but the degree of head impact necessary to consistently induce TON is not well characterized, and it is examined here. Methods Traumatic skull impacts to C57BL/6J mice were induced using an electromagnetic controlled impact device. One impact performed at two depths (mild and severe), as well as three and five repetitive impacts with an interconcussion interval of 48 hours, were tested. Optokinetic responses (OKRs) and retinal ganglion cell (RGC) loss were measured. Results Five repetitive mild impacts significantly decreased OKR scores and RGC numbers compared with control mice 10 weeks after initial impact, with maximal pathology observed by 6 weeks and partial but significant loss present by 3 weeks. One severe impact induced similar TON. Three mild impacts also induced early OKR and RGC loss, but one mild impact did not. Equivalent degrees of TON were induced bilaterally, and a significant correlation was observed between OKR scores and RGC numbers. Conclusions Repetitive, mild closed head trauma in mice induces progressive RGC and vision loss that worsens with increasing impacts. Translational Relevance Results detail a reproducible model of TON that provides a reliable platform for studying potential treatments over a 3- to 6-week time course.
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Affiliation(s)
- Reas S Khan
- Department of Ophthalmology, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Ahmara G Ross
- Department of Ophthalmology, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA.,Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Puya Aravand
- Department of Ophthalmology, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Kimberly Dine
- Department of Ophthalmology, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Evan B Selzer
- Thomas Jefferson University School of Medicine, Philadelphia, PA, USA
| | - Kenneth S Shindler
- Department of Ophthalmology, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA.,Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
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26
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Ma C, Zhang M, Liu L, Zhang P, Liu D, Zheng X, Zhong X, Wang G. Low-dose cannabinoid receptor 2 agonist induces microglial activation in a cancer pain-morphine tolerance rat model. Life Sci 2021; 264:118635. [PMID: 33131746 DOI: 10.1016/j.lfs.2020.118635] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/11/2020] [Accepted: 10/18/2020] [Indexed: 12/15/2022]
Abstract
AIMS Cancer pain seriously affects the life quality of patients. Morphine is commonly used for cancer pain, but tolerance development limits its clinical administration. Central immune signaling is important in the development of cancer pain and morphine tolerance. Cannabinoid receptor 2 (CB2) inhibits cancer pain and morphine tolerance by regulating central immune signaling. In the present study, we investigated the mechanisms of central immune signaling involved in morphine tolerance inhibition by the CB2 agonist AM1241 in cancer pain treatment. MAIN METHODS Rats were implanted with tumor cells and divided into 4 groups: Vehicle (PBS), 0.07 μg AM1241, 0.03 μg AM1241, and AM630 (10 μg) + AM1241 (0.07 μg). All groups received morphine (20 μg/day, i.t.) for 8 days. AM630 (CB2 antagonist) was intrathecally injected 30 min before AM1241, and AM1241 was intrathecally injected 30 min before morphine. The spinal cord (SC) and dorsal root ganglion (DRG) were collected to determine the expression of Toll-like receptor 4 (TLR4), the p38 mitogen-activated protein kinase (MAPK), microglial markers, interleukin (IL)-1β, and tumor necrosis factor (TNF)-α. KEY FINDINGS The expression of TLR4, p38 MAPK, microglial markers, IL-1β, and TNF-α was significantly higher in AM1241-pretreated groups than in the vehicle group (P < 0.05). No difference in microglial markers, IL-1β, and TNF-α expression was detected in the AM630 + AM1241 group compared with the vehicle group. SIGNIFICANCE Our results suggest that in a cancer pain-morphine tolerance model, an i.t. non-analgesic dose of AM1241 induces microglial activation and IL-1β TNF-α upregulation in SC and DRG via the CB2 receptor pathway.
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Affiliation(s)
- Chao Ma
- Department of Anesthesiology, The Fourth Hospital of Harbin Medical University, Harbin, China
| | - Mingyue Zhang
- Department of Anesthesiology, Harbin Medical University Cancer Hospital, Harbin, China
| | - Li Liu
- Department of Anesthesiology, Harbin Medical University Cancer Hospital, Harbin, China
| | - Pinyi Zhang
- Department of Anesthesiology, Harbin Medical University Cancer Hospital, Harbin, China
| | - Dandan Liu
- Department of Anesthesiology, The Fourth Hospital of Harbin Medical University, Harbin, China
| | - Xiaoyu Zheng
- Department of Anesthesiology, Harbin Medical University Cancer Hospital, Harbin, China
| | - Xuelai Zhong
- Department of Anesthesiology, The Fourth Hospital of Harbin Medical University, Harbin, China
| | - Guonian Wang
- Department of Anesthesiology, The Fourth Hospital of Harbin Medical University, Harbin, China; Pain Research Institute of Heilongjiang Academy of Medical Sciences, Harbin, China.
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CB2 Receptor in Microglia: The Guardian of Self-Control. Int J Mol Sci 2020; 22:ijms22010019. [PMID: 33375006 PMCID: PMC7792761 DOI: 10.3390/ijms22010019] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/16/2020] [Accepted: 12/18/2020] [Indexed: 12/12/2022] Open
Abstract
Microglia are key to maintaining the homeostasis of the brain. These immune cells of the brain can be our biggest ally in fighting infections, but can worsen pathology or hinder recovery when uncontrolled. Thus, understanding how microglia contribute to neuroinflammatory processes and how their activity can be controlled is of great importance. It is known that activation of endocannabinoid system, and especially the cannabinoid type 2 receptor (CB2R), decreases inflammation. Alongside its non-psychoactive effect, it makes the CB2R receptor a perfect target for treating diseases accompanied by neuroinflammation including neurodegenerative diseases. However, the exact mechanisms by which CB2R regulates microglial activity are not yet understood. Here, we review the current knowledge on the roles of microglial CB2R from in vitro and in vivo studies. We look into CB2R function under physiological and pathological conditions and focus on four different disease models representing chronic and acute inflammation. We highlight open questions and controversies and provide an update on the latest discoveries that were enabled by the development of novel technologies. Also, we discuss the recent findings on the role of microglia CB2R in cognition and its role in neuron–microglia communication.
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28
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Spyridakos D, Papadogkonaki S, Dionysopoulou S, Mastrodimou N, Polioudaki H, Thermos K. Effect of acute and subchronic administration of (R)-WIN55,212-2 induced neuroprotection and anti inflammatory actions in rat retina: CB1 and CB2 receptor involvement. Neurochem Int 2020; 142:104907. [PMID: 33220388 DOI: 10.1016/j.neuint.2020.104907] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/30/2020] [Accepted: 11/15/2020] [Indexed: 01/09/2023]
Abstract
Cannabinoids have been shown to protect the retina from ischemic/excitotoxic insults. The aim of the present study was to investigate the neuroprotective and anti-inflammatory properties of the synthetic cannabinoid (R)-WIN55,212-2 (CB1/CB2 receptor agonist) when administered acutely or subchronically in control and AMPA treated retinas. Sprague-Dawley rats were intravitreally administered (acutely) with vehicle or AMPA, in the absence or presence of (R)-WIN55,212-2 (10-7-10-4M) alone or in combination with AM251 [CB1 receptor antagonist/inverse agonist,10-4M] and AM630 (CB2 receptor antagonist,10-4M). In addition, AMPA was co-administered with the racemic (R,S)-WIN55,212 (10-4Μ). (R)-WIN55,212-2 was also administered subchronically (25,100 μg/kg,i.p.,4d) in control and AMPA treated rats. Immunohistochemical studies were performed using antibodies against the CB1R, and retinal markers for retinal neurons (brain nitric oxide synthetase, bNOS) and microglia (ionized calcium binding adaptor molecule 1, Iba1). ELISA assay was employed to assess TNFα levels in AMPA treated retinas. Intravitreal administration of (R)-WIN55,212-2 reversed the AMPA induced loss of bNOS expressing amacrine cells, an effect that was blocked by both AM251 and AM630. (R,S)WIN55,212 had no effect. (R)-WIN55,212-2 also reduced a) the AMPA induced activation of microglia, by activating CB2 receptors that were shown to be colocalized with Iba1+ reactive microglial cells, and b) TNFα levels in retina. (R)-WIN55,212-2 administered subchronically led to the downregulation of CB1 receptors at the high dose of 100 μg/kg(i.p.), and to the attenuation of the WIN55,212-2 induced neuroprotection of amacrine cells. At the same dose, (R)-WIN55,212-2 did not attenuate the AMPA induced increase in the number of reactive microglia cells, suggesting CB2 receptor downregulation under subchronic conditions. This study provides new findings regarding the role of CB1 and CB2 receptor activation by the synthetic cannabinoid (R)-WIN55,212-2, administered acutely or sub-chronically, on neuron viability and microglia activation in healthy and diseased retina.
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MESH Headings
- Animals
- Anti-Inflammatory Agents/administration & dosage
- Benzoxazines/administration & dosage
- Dose-Response Relationship, Drug
- Drug Administration Schedule
- Female
- Male
- Morpholines/administration & dosage
- Naphthalenes/administration & dosage
- Neuroprotective Agents/administration & dosage
- Rats
- Rats, Sprague-Dawley
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/agonists
- Receptor, Cannabinoid, CB2/metabolism
- Retina/drug effects
- Retina/metabolism
- alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/toxicity
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Affiliation(s)
- Dimitris Spyridakos
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Crete, 71003, Greece.
| | - Sofia Papadogkonaki
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Crete, 71003, Greece.
| | - Stavroula Dionysopoulou
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Crete, 71003, Greece.
| | - Niki Mastrodimou
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Crete, 71003, Greece.
| | - Hara Polioudaki
- Department of Biochemistry, School of Medicine, University of Crete, Heraklion, Crete, 71003, Greece.
| | - Kyriaki Thermos
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Crete, 71003, Greece.
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29
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Raloxifene as Treatment for Various Types of Brain Injuries and Neurodegenerative Diseases: A Good Start. Int J Mol Sci 2020; 21:ijms21207586. [PMID: 33066585 PMCID: PMC7589740 DOI: 10.3390/ijms21207586] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/10/2020] [Accepted: 10/12/2020] [Indexed: 02/06/2023] Open
Abstract
Recent studies have shown that the selective estrogen receptor modulator (SERM) raloxifene had pronounced protective effects against progressing brain damage after traumatic brain injury (TBI) in mice. These studies, indicating beneficial effects of raloxifene for brain health, prompted the study of the history and present state of knowledge of this topic. It appears that, apart from raloxifene, to date, four nonrelated compounds have shown comparable beneficial effects—fucoidan, pifithrin, SMM-189 (5-dihydroxy-phenyl]-phenyl-methanone), and translocator protein (TSPO) ligands. Raloxifene, however, is ahead of the field, as for more than two decades it has been used in medical practice for various chronic ailments in humans. Thus, apart from different types of animal and cell culture studies, it has also been assessed in various human clinical trials, including assaying its effects on mild cognitive impairments. Regarding cell types, raloxifene protects neurons from cell death, prevents glial activation, ameliorates myelin damage, and maintains health of endothelial cells. At whole central nervous system (CNS) levels, raloxifene ameliorated mild cognitive impairments, as seen in clinical trials, and showed beneficial effects in animal models of Parkinson’s disease. Moreover, with stroke and TBI in animal models, raloxifene showed curative effects. Furthermore, raloxifene showed healing effects regarding multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS) in cell culture. The adverse biological signals typical of these conditions relate to neuronal activity, neurotransmitters and their receptors, plasticity, inflammation, oxidative stress, nitric oxide, calcium homeostasis, cell death, behavioral impairments, etc. Raloxifene favorably modulates these signals toward cell health—on the one hand, by modulating gene expression of the relevant proteins, for example by way of its binding to the cell nuclear estrogen receptors ERα and ERβ (genomic effects) and, on the other hand (nongenomic effects) by modulation of mitochondrial activity, reduction of oxidative stress and programmed cell death, maintaining metabolic balance, degradation of Abeta, and modulation of intracellular cholesterol levels. More specifically regarding Alzheimer’s disease, raloxifene may not cure diagnosed Alzheimer’s disease. However, the onset of Alzheimer’s disease may be delayed or arrested by raloxifene’s capability to attenuate mild cognitive impairment. Mild cognitive impairment is a condition that may precede diagnosis of Alzheimer’s disease. In this review, relatively new insights are addressed regarding the notion that Alzheimer’s disease can be caused by bacterial (as well as viral) infections, together with the most recent findings that raloxifene can counteract infections of at least some bacterial and viral strains. Thus, here, an overview of potential treatments of neurodegenerative disease by raloxifene is presented, and attention is paid to subcellular molecular biological pathways that may be involved.
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30
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Reddy V, Grogan D, Ahluwalia M, Salles ÉL, Ahluwalia P, Khodadadi H, Alverson K, Nguyen A, Raju SP, Gaur P, Braun M, Vale FL, Costigliola V, Dhandapani K, Baban B, Vaibhav K. Targeting the endocannabinoid system: a predictive, preventive, and personalized medicine-directed approach to the management of brain pathologies. EPMA J 2020; 11:217-250. [PMID: 32549916 PMCID: PMC7272537 DOI: 10.1007/s13167-020-00203-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 03/10/2020] [Indexed: 02/07/2023]
Abstract
Cannabis-inspired medical products are garnering increasing attention from the scientific community, general public, and health policy makers. A plethora of scientific literature demonstrates intricate engagement of the endocannabinoid system with human immunology, psychology, developmental processes, neuronal plasticity, signal transduction, and metabolic regulation. Despite the therapeutic potential, the adverse psychoactive effects and historical stigma, cannabinoids have limited widespread clinical application. Therefore, it is plausible to weigh carefully the beneficial effects of cannabinoids against the potential adverse impacts for every individual. This is where the concept of "personalized medicine" as a promising approach for disease prediction and prevention may take into the account. The goal of this review is to provide an outline of the endocannabinoid system, including endocannabinoid metabolizing pathways, and will progress to a more in-depth discussion of the therapeutic interventions by endocannabinoids in various neurological disorders.
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Affiliation(s)
- Vamsi Reddy
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA USA
| | - Dayton Grogan
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA USA
| | - Meenakshi Ahluwalia
- Department of Pathology, Medical College of Georgia, Augusta University, Augusta, GA USA
| | - Évila Lopes Salles
- Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia, Augusta University, Augusta, GA USA
| | - Pankaj Ahluwalia
- Department of Pathology, Medical College of Georgia, Augusta University, Augusta, GA USA
| | - Hesam Khodadadi
- Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia, Augusta University, Augusta, GA USA
| | - Katelyn Alverson
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA USA
| | - Andy Nguyen
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA USA
| | - Srikrishnan P. Raju
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA USA
- Brown University, Providence, RI USA
| | - Pankaj Gaur
- Georgia Cancer Center, Augusta University, Augusta, GA USA
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC, USA
| | - Molly Braun
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA USA
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, USA
- VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, USA
| | - Fernando L. Vale
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA USA
| | | | - Krishnan Dhandapani
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA USA
| | - Babak Baban
- Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia, Augusta University, Augusta, GA USA
| | - Kumar Vaibhav
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA USA
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31
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Yu Y, Li L, Nguyen DT, Mustafa SM, Moore BM, Jiang J. Inverse Agonism of Cannabinoid Receptor Type 2 Confers Anti-inflammatory and Neuroprotective Effects Following Status Epileptics. Mol Neurobiol 2020; 57:2830-2845. [PMID: 32378121 DOI: 10.1007/s12035-020-01923-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 04/22/2020] [Indexed: 12/13/2022]
Abstract
Prolonged status epilepticus (SE) in humans causes high mortality and brain inflammation-associated neuronal injury and morbidity in survivors. Currently, the only effective treatment is to terminate the seizures swiftly to prevent brain damage. However, reliance on acute therapies alone would be imprudent due to the required short response time. Follow-on therapies that can be delivered well after the SE onset are in an urgent need. Cannabinoid receptor type 2 (CB2), a G protein-coupled receptor that can be expressed by activated brain microglia, has emerged as an appealing anti-inflammatory target for brain conditions. In the current study, we reported that the CB2 inverse agonism by our current lead compound SMM-189 largely prevented the rat primary microglia-mediated inflammation and showed moderate neuroprotection against N-methyl-D-aspartic acid (NMDA) receptor-mediated excitotoxicity in rat primary hippocampal cultures containing both neurons and glia. Using a classical mouse model of epilepsy, in which SE was induced by systemic administration of kainate (30 mg/kg, i.p.) and proceeded for 1 h, we demonstrated that SE downregulated the CB1 but slightly upregulated CB2 receptor in the hippocampus. Transient treatment with SMM-189 (6 mg/kg, i.p., b.i.d.) after the SE was interrupted by diazepam (10 mg/kg, i.p.) prevented the seizure-induced cytokine surge in the brain, neuronal death, and behavioral impairments 24 h after SE. Our results suggest that CB2 inverse agonism might provide an adjunctive anti-inflammatory therapy that can be delivered hours after SE onset, together with NMDA receptor blockers and first-line anti-convulsants, to reduce brain injury and functional deficits following prolonged seizures.
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Affiliation(s)
- Ying Yu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Lexiao Li
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Davis T Nguyen
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Suni M Mustafa
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Bob M Moore
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Jianxiong Jiang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, 38163, USA.
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Evans LP, Woll AW, Wu S, Todd BP, Hehr N, Hedberg-Buenz A, Anderson MG, Newell EA, Ferguson PJ, Mahajan VB, Harper MM, Bassuk AG. Modulation of Post-Traumatic Immune Response Using the IL-1 Receptor Antagonist Anakinra for Improved Visual Outcomes. J Neurotrauma 2020; 37:1463-1480. [PMID: 32056479 PMCID: PMC7249480 DOI: 10.1089/neu.2019.6725] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The purpose of this study was to characterize acute changes in inflammatory pathways in the mouse eye after blast-mediated traumatic brain injury (bTBI) and to determine whether modulation of these pathways could protect the structure and function of retinal ganglion cells (RGC). The bTBI was induced in C57BL/6J male mice by exposure to three 20 psi blast waves directed toward the head with the body shielded, with an inter-blast interval of one hour. Acute cytokine expression in retinal tissue was measured through reverse transcription-quantitative polymerase chain reaction (RT-qPCR) four hours post-blast. Increased retinal expression of interleukin (lL)-1β, IL-1α, IL-6, and tumor necrosis factor (TNF)α was observed in bTBI mice exposed to blast when compared with shams, which was associated with activation of microglia and macroglia reactivity, assessed via immunohistochemistry with ionized calcium binding adaptor molecule 1 and glial fibrillary acidic protein, respectively, one week post-blast. Blockade of the IL-1 pathway was accomplished using anakinra, an IL-1RI antagonist, administered intra-peritoneally for one week before injury and continuing for three weeks post-injury. Retinal function and RGC layer thickness were evaluated four weeks post-injury using pattern electroretinogram (PERG) and optical coherence tomography (OCT), respectively. After bTBI, anakinra treatment resulted in a preservation of RGC function and RGC structure when compared with saline treated bTBI mice. Optic nerve integrity analysis demonstrated a trend of decreased damage suggesting that IL-1 blockade also prevents axonal damage after blast. Blast exposure results in increased retinal inflammation including upregulation of pro-inflammatory cytokines and activation of resident microglia and macroglia. This may explain partially the RGC loss we observed in this model, as blockade of the acute inflammatory response after injury with the IL-1R1 antagonist anakinra resulted in preservation of RGC function and RGC layer thickness.
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Affiliation(s)
- Lucy P Evans
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, USA.,Medical Scientist Training Program, University of Iowa, Iowa City, Iowa, USA
| | - Addison W Woll
- Department of Psychiatry, University of Iowa, Iowa City, Iowa, USA
| | - Shu Wu
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, USA
| | - Brittany P Todd
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, USA
| | - Nicole Hehr
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, USA
| | - Adam Hedberg-Buenz
- The Iowa City Department of Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, USA.,Department of Molecular Physiology and Biophysics, and University of Iowa, Iowa City, Iowa, USA
| | - Michael G Anderson
- The Iowa City Department of Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, USA.,Department of Molecular Physiology and Biophysics, and University of Iowa, Iowa City, Iowa, USA.,Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, USA
| | | | - Polly J Ferguson
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, USA
| | - Vinit B Mahajan
- Omics Laboratory, Byers Eye Institute, Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, California, USA.,Veterans Affairs Palo Alto Health Care System, Palo Alto, California, USA
| | - Matthew M Harper
- The Iowa City Department of Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, USA.,Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, USA
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33
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Honig MG, Dorian CC, Worthen JD, Micetich AC, Mulder IA, Sanchez KB, Pierce WF, Del Mar NA, Reiner A. Progressive long-term spatial memory loss following repeat concussive and subconcussive brain injury in mice, associated with dorsal hippocampal neuron loss, microglial phenotype shift, and vascular abnormalities. Eur J Neurosci 2020; 54:5844-5879. [PMID: 32090401 PMCID: PMC7483557 DOI: 10.1111/ejn.14711] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 12/14/2022]
Abstract
There is considerable concern about the long‐term deleterious effects of repeat head trauma on cognition, but little is known about underlying mechanisms and pathology. To examine this, we delivered four air blasts to the left side of the mouse cranium, a week apart, with an intensity that causes deficits when delivered singly and considered “concussive,” or an intensity that does not yield significant deficits when delivered singly and considered “subconcussive.” Neither repeat concussive nor subconcussive blast produced spatial memory deficits at 4 months, but both yielded deficits at 14 months, and dorsal hippocampal neuron loss. Hierarchical cluster analysis of dorsal hippocampal microglia across the three groups based on morphology and expression of MHCII, CX3CR1, CD68 and IBA1 revealed five distinct phenotypes. Types 1A and 1B microglia were more common in sham mice, linked to better neuron survival and memory, and appeared mildly activated. By contrast, 2B and 2C microglia were more common in repeat concussive and subconcussive mice, linked to poorer neuron survival and memory, and characterized by low expression levels and attenuated processes, suggesting they were de‐activated and dysfunctional. In addition, endothelial cells in repeat concussive mice exhibited reduced CD31 and eNOS expression, which was correlated with the prevalence of type 2B and 2C microglia. Our findings suggest that both repeat concussive and subconcussive head injury engender progressive pathogenic processes, possibly through sustained effects on microglia that over time lead to increased prevalence of dysfunctional microglia, adversely affecting neurons and blood vessels, and thereby driving neurodegeneration and memory decline.
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Affiliation(s)
- Marcia G Honig
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Conor C Dorian
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - John D Worthen
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Anthony C Micetich
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Isabelle A Mulder
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Katelyn B Sanchez
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - William F Pierce
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Nobel A Del Mar
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Anton Reiner
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA.,Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, TN, USA
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34
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Tanaka M, Sackett S, Zhang Y. Endocannabinoid Modulation of Microglial Phenotypes in Neuropathology. Front Neurol 2020; 11:87. [PMID: 32117037 PMCID: PMC7033501 DOI: 10.3389/fneur.2020.00087] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 01/24/2020] [Indexed: 12/12/2022] Open
Abstract
Microglia, the resident immune cells of the central nervous system, mediate brain homeostasis by controlling neuronal proliferation/differentiation and synaptic activity. In response to external signals from neuropathological conditions, homeostatic (M0) microglia can adopt one of two activation states: the classical (M1) activation state, which secretes mediators of the proinflammatory response, and the alternative (M2) activation state, which presumably mediates the resolution of neuroinflammation and tissue repair/remodeling. Since chronic inflammatory activation of microglia is correlated with several neurodegenerative diseases, functional modulation of microglial phenotypes has been considered as a potential therapeutic strategy. The endocannabinoid (eCB) system, composed of cannabinoid receptors and ligands and their metabolic/biosynthetic enzymes, has been shown to activate anti-inflammatory signaling pathways that modulate immune cell functions. Growing evidence has demonstrated that endogenous, synthetic, and plant-derived eCB agonists possess therapeutic effects on several neuropathologies; however, the molecular mechanisms that mediate the anti-inflammatory effects have not yet been identified. Over the last decade, it has been revealed that the eCB system modulates microglial activation and population. In this review, we thoroughly examine recent studies on microglial phenotype modulation by eCB in neuroinflammatory and neurodegenerative disease conditions. We hypothesize that cannabinoid 2 receptor (CB2R) signaling shifts the balance of expression between neuroinflammatory (M1-type) genes, neuroprotective (M2-type) genes, and homeostatic (M0-type) genes toward the latter two gene expressions, by which microglia acquire therapeutic functionality.
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Affiliation(s)
- Mikiei Tanaka
- Department of Anatomy, Physiology and Genetics, Uniformed Services University Health Sciences, Bethesda, MD, United States
| | - Scott Sackett
- Department of Anatomy, Physiology and Genetics, Uniformed Services University Health Sciences, Bethesda, MD, United States
| | - Yumin Zhang
- Department of Anatomy, Physiology and Genetics, Uniformed Services University Health Sciences, Bethesda, MD, United States
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35
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Honig MG, Del Mar NA, Henderson DL, Ragsdale TD, Doty JB, Driver JH, Li C, Fortugno AP, Mitchell WM, Perry AM, Moore BM, Reiner A. Amelioration of visual deficits and visual system pathology after mild TBI via the cannabinoid Type-2 receptor inverse agonism of raloxifene. Exp Neurol 2019; 322:113063. [DOI: 10.1016/j.expneurol.2019.113063] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 08/09/2019] [Accepted: 09/07/2019] [Indexed: 11/29/2022]
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