1
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Gouda MA, Abu-Hashem AA, Ameen TA, Salem MA, Aljuhani A. Recent Progress in Synthetic Chemistry and Biological Activities of Pyrimido[
4,5- b] Quinoline Derivatives (Part III). MINI-REV ORG CHEM 2024; 21:779-792. [DOI: 10.2174/1570193x20666230626101436] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/09/2023] [Accepted: 05/29/2023] [Indexed: 07/10/2024]
Abstract
Abstract:
Amongst heterocyclic compounds, quinoline and pyrimidine are advantaged scaffolds that
appear as significant assembly motifs for the development of new drug entities. Moreover, quinolinepyrimidine-
inspired hybrids have a number of biological characteristics that are known. In addition,
many pyrimido[4,5-b]quinoline ring systems (PyQs4,5-b), specifically concerning medicinal chemistry,
have been reported over the past decade. The synthesis of (PyQs4,5-b) using barbituric acid, thiobarbituric
acid, pyrimidine, and their derivatives is presented in this review. The preparation of
PyQs4,5-b was clarified through the following chemical reactions: Friedländer, Vilsmeier-Haack
formylation, Hantzsch-like reaction, and one-pot three-component reaction.
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Affiliation(s)
- Moustafa A. Gouda
- Department of Chemistry, Faculty of Science and Arts, Taibah University, AlUla, Medina, Saudia Arabia
- Department
of Chemistry, Faculty of Science, Mansoura University, Mansoura, 35516, Egypt
| | - Ameen A. Abu-Hashem
- Photochemistry Department (Heterocyclic
Unit), National Research Centre, Dokki, Giza, 12622, Egypt
- Chemistry Departments, Faculty of Science, Jazan
University, Jazan, 45142, Saudi Arabia
| | - Tahah A. Ameen
- Chemistry Departments, Faculty of Science, Jazan
University, Jazan, 45142, Saudi Arabia
| | - Mohammed A. Salem
- Department of Chemistry, Faculty of Science & Arts, King Khalid University,
Saudia Arabia
- Department of Chemistry, Faculty of Science (Boyes), Al-Azhar University, Nasr City, Cairo, 11284,
Egypt
| | - Ateyatallah Aljuhani
- Department of Chemistry, College of Science, Taibah University, Al-Madinah Al-Munawarah, 30002, Saudi
Arabia
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2
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Fairley LH, Lai KO, Grimm A, Eckert A, Barron AM. The mitochondrial translocator protein (TSPO) in Alzheimer's disease: Therapeutic and immunomodulatory functions. Biochimie 2024:S0300-9084(24)00162-7. [PMID: 38971458 DOI: 10.1016/j.biochi.2024.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 07/03/2024] [Accepted: 07/03/2024] [Indexed: 07/08/2024]
Abstract
The translocator protein (TSPO) has been widely investigated as a PET-imaging biomarker of neuroinflammation and, more recently, as a therapeutic target for the treatment of neurodegenerative disease. TSPO ligands have been shown to exert neuroprotective effects in vivo and in vitro models of Alzheimer's disease (AD), by reducing toxic beta amyloid peptides, and attenuating brain atrophy. Recent transcriptomic and proteomic analyses, and the generation of TSPO-KO mice, have enabled new insights into the mechanistic function of TSPO in AD. Using a multi-omics approach in both TSPO-KO- and TSPO ligand-treated mice, we have demonstrated a key role for TSPO in microglial respiratory metabolism and phagocytosis in AD. In this review, we discuss emerging evidence for therapeutic and immunomodulatory functions of TSPO in AD, and new tools for studying TSPO in the brain.
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Affiliation(s)
- Lauren H Fairley
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 308232, Singapore
| | - Kei Onn Lai
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 308232, Singapore
| | - Amandine Grimm
- Transfaculty Research Platform, Molecular & Cognitive Neuroscience, Neurobiology Laboratory for Brain Aging and Mental Health, University of Basel, Basel, Switzerland; Psychiatric University Clinics, Basel, Switzerland
| | - Anne Eckert
- Transfaculty Research Platform, Molecular & Cognitive Neuroscience, Neurobiology Laboratory for Brain Aging and Mental Health, University of Basel, Basel, Switzerland; Psychiatric University Clinics, Basel, Switzerland
| | - Anna M Barron
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 308232, Singapore.
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3
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Hector M, Langmann T, Wolf A. Translocator protein (18 kDa) (Tspo) in the retina and implications for ocular diseases. Prog Retin Eye Res 2024; 100:101249. [PMID: 38430990 DOI: 10.1016/j.preteyeres.2024.101249] [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: 12/05/2023] [Revised: 02/28/2024] [Accepted: 02/29/2024] [Indexed: 03/05/2024]
Abstract
Translocator protein (18 kDa) (Tspo), formerly known as peripheral benzodiazepine receptor is a highly conserved transmembrane protein primarily located in the outer mitochondrial membrane. In the central nervous system (CNS), especially in glia cells, Tspo is upregulated upon inflammation. Consequently, Tspo was used as a tool for diagnostic in vivo imaging of neuroinflammation in the brain and as a potential therapeutic target. Several synthetic Tspo ligands have been explored as immunomodulatory and neuroprotective therapy approaches. Although the function of Tspo and how its ligands exert these beneficial effects is not fully clear, it became a research topic of interest, especially in ocular diseases in the past few years. This review summarizes state-of-the-art knowledge of Tspo expression and its proposed functions in different cells of the retina including microglia, retinal pigment epithelium and Müller cells. Tspo is involved in cytokine signaling, oxidative stress and reactive oxygen species production, calcium signaling, neurosteroid synthesis, energy metabolism, and cholesterol efflux. We also highlight recent developments in preclinical models targeting Tspo and summarize the relevance of Tspo biology for ocular and retinal diseases. We conclude that glial upregulation of Tspo in different ocular pathologies and the use of Tspo ligands as promising therapeutic approaches in preclinical studies underline the importance of Tspo as a potential disease-modifying protein.
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Affiliation(s)
- Mandy Hector
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Centre for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
| | - Anne Wolf
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Centre for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
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4
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Bobotis BC, Halvorson T, Carrier M, Tremblay MÈ. Established and emerging techniques for the study of microglia: visualization, depletion, and fate mapping. Front Cell Neurosci 2024; 18:1317125. [PMID: 38425429 PMCID: PMC10902073 DOI: 10.3389/fncel.2024.1317125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 01/15/2024] [Indexed: 03/02/2024] Open
Abstract
The central nervous system (CNS) is an essential hub for neuronal communication. As a major component of the CNS, glial cells are vital in the maintenance and regulation of neuronal network dynamics. Research on microglia, the resident innate immune cells of the CNS, has advanced considerably in recent years, and our understanding of their diverse functions continues to grow. Microglia play critical roles in the formation and regulation of neuronal synapses, myelination, responses to injury, neurogenesis, inflammation, and many other physiological processes. In parallel with advances in microglial biology, cutting-edge techniques for the characterization of microglial properties have emerged with increasing depth and precision. Labeling tools and reporter models are important for the study of microglial morphology, ultrastructure, and dynamics, but also for microglial isolation, which is required to glean key phenotypic information through single-cell transcriptomics and other emerging approaches. Strategies for selective microglial depletion and modulation can provide novel insights into microglia-targeted treatment strategies in models of neuropsychiatric and neurodegenerative conditions, cancer, and autoimmunity. Finally, fate mapping has emerged as an important tool to answer fundamental questions about microglial biology, including their origin, migration, and proliferation throughout the lifetime of an organism. This review aims to provide a comprehensive discussion of these established and emerging techniques, with applications to the study of microglia in development, homeostasis, and CNS pathologies.
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Affiliation(s)
- Bianca Caroline Bobotis
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Centre for Advanced Materials and Related Technology, Victoria, BC, Canada
| | - Torin Halvorson
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
- Department of Surgery, University of British Columbia, Vancouver, BC, Canada
- British Columbia Children’s Hospital Research Institute, Vancouver, BC, Canada
| | - Micaël Carrier
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Département de Psychiatrie et de Neurosciences, Faculté de Médecine, Université Laval, Québec City, QC, Canada
- Axe neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Centre for Advanced Materials and Related Technology, Victoria, BC, Canada
- Axe neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
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5
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Mills KA, Du Y, Coughlin JM, Foss CA, Horti AG, Jenkins K, Skorobogatova Y, Spiro E, Motley CS, Dannals RF, Song JJ, Choi YR, Redding-Ochoa J, Troncoso J, Dawson VL, Kam TI, Pomper MG, Dawson TM. Exploring [ 11C]CPPC as a CSF1R-targeted PET Imaging Marker for Early Parkinson's Disease Severity. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2023.05.28.23290647. [PMID: 37398476 PMCID: PMC10312881 DOI: 10.1101/2023.05.28.23290647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Neuroinflammation through enhanced innate immunity is thought play a role in the pathogenesis of Parkinson's disease (PD). Methods for monitoring neuroinflammation in living patients with PD are currently limited to positron emission tomography (PET) ligands that lack specificity in labeling immune cells in the nervous system. The colony stimulating factor 1 receptor (CSF1R) plays a crucial role in microglial function, an important cellular contributor to the nervous system's innate immune response. Using immunologic methods, we show that CSF1R in human brain is colocalized with the microglial marker, ionized calcium binding adaptor molecule 1 (Iba1). In PD, CSF1R immunoreactivity is significantly increased in PD across multiple brain regions, with the largest differences in the midbrain versus controls. Autoradiography revealed significantly increased [3H]JHU11761 binding in the inferior parietal cortex of PD patients. PET imaging demonstrated that higher [11C]CPPC binding in the striatum was associated with greater motor disability in PD. Furthermore, increased [11C]CPPC binding in various regions correlated with more severe motor disability and poorer verbal fluency. This study finds that CSF1R expression is elevated in PD and that [11C]CPPC-PET imaging of CSF1R is indicative of motor and cognitive impairments in the early stages of the disease. Moreover, the study underscores the significance of CSF1R as a promising biomarker for neuroinflammation in Parkinson's disease, suggesting its potential use for non-invasive assessment of disease progression and severity, leading to earlier diagnosis and targeted interventions.
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Affiliation(s)
- Kelly A Mills
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Yong Du
- Johns Hopkins University School of Medicine, Russell H. Morgan Dept. of Radiology and Radiologic Science, Baltimore, MD, USA
| | - Jennifer M Coughlin
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Catherine A Foss
- Johns Hopkins University School of Medicine, Russell H. Morgan Dept. of Radiology and Radiologic Science, Baltimore, MD, USA
| | - Andrew G Horti
- Johns Hopkins University School of Medicine, Russell H. Morgan Dept. of Radiology and Radiologic Science, Baltimore, MD, USA
| | - Katelyn Jenkins
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Yana Skorobogatova
- Johns Hopkins University School of Medicine, Russell H. Morgan Dept. of Radiology and Radiologic Science, Baltimore, MD, USA
| | - Ergi Spiro
- Johns Hopkins University School of Medicine, Russell H. Morgan Dept. of Radiology and Radiologic Science, Baltimore, MD, USA
| | - Chelsie S Motley
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Robert F Dannals
- Johns Hopkins University School of Medicine, Russell H. Morgan Dept. of Radiology and Radiologic Science, Baltimore, MD, USA
| | - Jae-Jin Song
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Yu Ree Choi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Javier Redding-Ochoa
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Department of Pathology (Neuropathology), Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Juan Troncoso
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Department of Pathology (Neuropathology), Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Valina L Dawson
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Tae-In Kam
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Martin G Pomper
- Johns Hopkins University School of Medicine, Russell H. Morgan Dept. of Radiology and Radiologic Science, Baltimore, MD, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, US
- Department of Radiology, University of Texas Southwestern School of Medicine, Dallas, TX, USA (current)
| | - Ted M Dawson
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, US
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6
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Park M, Ha J, Lee Y, Choi HS, Kim BS, Jeong YK. Low-moderate dose whole-brain γ-ray irradiation modulates the expressions of glial fibrillary acidic protein and intercellular adhesion molecule-1 in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's disease mouse model. Neurobiol Aging 2023; 132:175-184. [PMID: 37837733 DOI: 10.1016/j.neurobiolaging.2023.06.015] [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: 02/28/2023] [Revised: 06/22/2023] [Accepted: 06/24/2023] [Indexed: 10/16/2023]
Abstract
The anti-inflammatory efficacy of radiation therapy (RT) with single fractions below 1.0 Gy has been demonstrated in Alzheimer's disease mouse models. As neuroinflammation is also a major pathological feature of Parkinson's disease (PD), RT may also be effective in PD treatment. Therefore, this study aimed to investigate the anti-inflammatory effect of low-moderate dose RT (LMDRT, 0.6 Gy/single dose, for 5 days) exposure in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 30 mg/kg, intraperitoneally, for 5 consecutive days)-induced PD mouse model. Importantly, LMDRT reduced the levels of glial fibrillary acidic protein and intercellular adhesion molecule-1 (CD54) in the striatum region, which increased following MPTP administration. LMDRT also modulated inflammatory gene expression patterns in the substantia nigra region of the MPTP-treated mice. However, LMDRT had no direct effects on the severe loss of dopaminergic neurons and impaired motor behavior in the rotarod test. These results indicate that LMDRT has anti-inflammatory effects by modulating neuroinflammatory factors, including glial fibrillary acidic protein and intercellular adhesion molecule-1, but showed no behavioral improvements or neuroprotection in the MPTP-induced mouse model of PD.
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MESH Headings
- Animals
- Mice
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/metabolism
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/pharmacology
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/therapeutic use
- Brain/metabolism
- Brain/radiation effects
- Disease Models, Animal
- Dopaminergic Neurons/pathology
- Glial Fibrillary Acidic Protein/metabolism
- Intercellular Adhesion Molecule-1/metabolism
- Intercellular Adhesion Molecule-1/pharmacology
- Intercellular Adhesion Molecule-1/therapeutic use
- Mice, Inbred C57BL
- Parkinson Disease/metabolism
- Parkinson Disease/radiotherapy
- Substantia Nigra/metabolism
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Affiliation(s)
- Mijeong Park
- Radiological and Medical Support Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Jimin Ha
- Radiological and Medical Support Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea; Division of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul, Republic of Korea
| | - Yuri Lee
- Radiological and Medical Support Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea; Division of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul, Republic of Korea
| | - Hoon-Seong Choi
- Research Animal Resource Center, Korea Institute of Science and Technology, Seoul, Republic of Korea
| | - Byoung Soo Kim
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Youn Kyoung Jeong
- Radiological and Medical Support Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea.
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7
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Prasher P, Mall T, Sharma M. Synthesis and biological profile of benzoxazolone derivatives. Arch Pharm (Weinheim) 2023; 356:e2300245. [PMID: 37379239 DOI: 10.1002/ardp.202300245] [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: 05/04/2023] [Revised: 06/07/2023] [Accepted: 06/09/2023] [Indexed: 06/30/2023]
Abstract
The benzoxazolone nucleus is an ideal scaffold for drug design, owing to its discrete physicochemical profile, bioisosteric preference over pharmacokinetically weaker moieties, weakly acidic behavior, presence of both lipophilic and hydrophilic fragments on a single framework, and a wider choice of chemical modification on the benzene and oxazolone rings. These properties apparently influence the interactions of benzoxazolone-based derivatives with their respective biological targets. Hence, the benzoxazolone ring is implicated in the synthesis and development of pharmaceuticals with a diverse biological profile ranging from anticancer, analgesics, insecticides, anti-inflammatory, and neuroprotective agents. This has further led to the commercialization of several benzoxazolone-based molecules and a few others under clinical trials. Nevertheless, the SAR exploration of benzoxazolone derivatives for the identification of potential "hits" followed by the screening of "leads" provides a plethora of opportunities for further exploration of the pharmacological profile of the benzoxazolone nucleus. In this review, we aim to present the biological profile of different derivatives based on the benzoxazolone framework.
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Affiliation(s)
- Parteek Prasher
- Department of Chemistry, University of Petroleum & Energy Studies, Energy Acres, Dehradun, India
| | - Tanisqa Mall
- Department of Chemistry, University of Petroleum & Energy Studies, Energy Acres, Dehradun, India
| | - Mousmee Sharma
- Department of Chemistry, Uttaranchal University, Dehradun, India
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8
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Tournier B, Bouteldja F, Amossé Q, Nicolaides A, Duarte Azevedo M, Tenenbaum L, Garibotto V, Ceyzériat K, Millet P. 18 kDa Translocator Protein TSPO Is a Mediator of Astrocyte Reactivity. ACS OMEGA 2023; 8:31225-31236. [PMID: 37663488 PMCID: PMC10468775 DOI: 10.1021/acsomega.3c03368] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/01/2023] [Indexed: 09/05/2023]
Abstract
An increase in astrocyte reactivity has been described in Alzheimer's disease and seems to be related to the presence of a pro-inflammatory environment. Reactive astrocytes show an increase in the density of the 18 kDa translocator protein (TSPO), but TSPO involvement in astrocyte functions remains poorly understood. The goal of this study was to better characterize the mechanisms leading to the increase in TSPO under inflammatory conditions and the associated consequences. For this purpose, the C6 astrocytic cell line was used in the presence of lipopolysaccharide (LPS) or TSPO overexpression mediated by the transfection of a plasmid encoding TSPO. The results show that nonlethal doses of LPS induced TSPO expression at mRNA and protein levels through a STAT3-dependent mechanism and increased the number of mitochondria per cell. LPS stimulated reactive oxygen species (ROS) production and decreased glucose consumption (quantified by the [18F]FDG uptake), and these effects were diminished by FEPPA, a TSPO antagonist. The transfection-mediated overexpression of TSPO induced ROS production, and this effect was blocked by FEPPA. In addition, a synergistic effect of overexpression of TSPO and LPS on ROS production was observed. These data show that the increase of TSPO in astrocytic cells is involved in the regulation of glucose metabolism and in the pro-inflammatory response. These data suggest that the overexpression of TSPO by astrocytes in Alzheimer's disease would have rather deleterious effects by promoting the pro-inflammatory response.
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Affiliation(s)
- Benjamin
B. Tournier
- Department
of Psychiatry, University Hospitals of Geneva, Geneva 1206, Switzerland
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
| | - Farha Bouteldja
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
| | - Quentin Amossé
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
| | - Alekos Nicolaides
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
| | - Marcelo Duarte Azevedo
- Laboratory
of Cellular and Molecular Neurotherapies, Center for Neuroscience
Research, Clinical Neuroscience Department, Lausanne University Hospital, Lausanne 1011, Switzerland
| | - Liliane Tenenbaum
- Laboratory
of Cellular and Molecular Neurotherapies, Center for Neuroscience
Research, Clinical Neuroscience Department, Lausanne University Hospital, Lausanne 1011, Switzerland
| | - Valentina Garibotto
- Division
of Nuclear Medicine, Diagnostic Department, University Hospitals of Geneva, Geneva 1206, Switzerland
- CIBM
Center for BioMedical Imaging; NIMTLab, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland
| | - Kelly Ceyzériat
- Department
of Psychiatry, University Hospitals of Geneva, Geneva 1206, Switzerland
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
- Division
of Nuclear Medicine, Diagnostic Department, University Hospitals of Geneva, Geneva 1206, Switzerland
- CIBM
Center for BioMedical Imaging; NIMTLab, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland
| | - Philippe Millet
- Department
of Psychiatry, University Hospitals of Geneva, Geneva 1206, Switzerland
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
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9
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Angeloni E, Germelli L, Marchetti L, Da Pozzo E, Tremolanti C, Wetzel CH, Baglini E, Taliani S, Da Settimo F, Martini C, Costa B. The human microglial surveillant phenotype is preserved by de novo neurosteroidogenesis through the control of cholesterol homeostasis: Crucial role of 18 kDa Translocator Protein. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166751. [PMID: 37169037 DOI: 10.1016/j.bbadis.2023.166751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/04/2023] [Accepted: 05/05/2023] [Indexed: 05/13/2023]
Abstract
Neurodegenerative disease-associated microglia commonly exhibit harmful cholesterol accumulation that impairs their ability to resolve the neuroinflammatory response, contributing to disease onset and progression. Neurosteroids, whose levels have been often found significantly altered in brain diseases, are the most potent endogenous anti-inflammatory molecules exerting beneficial effects on activities of brain cells, including microglia. For the first time, the impact of neurosteroidogenesis on cholesterol homeostasis for the immune surveillance phenotype maintenance was investigated in a human microglia in vitro model. To enhance and inhibit neurosteroidogenesis, pharmacological stimulation and knock-down of 18 kDa Translocator Protein (TSPO), which is involved in the neurosteroidogenesis rate-limiting step, were used as experimental approaches, respectively. The obtained results point to an essential autocrine control of neurosteroidogenesis in orchestrating cholesterol trafficking in human microglia. TSPO pharmacological stimulation ensured cholesterol turnover by strengthening cholesterol efflux systems and preserving healthy immune surveillant phenotype. Conversely, TSPO knock-down induced an impairment of the controlled interplay among cholesterol synthesis, efflux, and metabolism mechanisms, leading to an excessive cholesterol accumulation and acquisition of a chronically activated dysfunctional phenotype. In this model, the exogenous neurosteroid administration restored proper the cholesterol clearance. The TSPO ability in promoting native neurosteroidogenesis opens the way to restore cholesterol homeostasis, and thus to maintain microglia proper functionality for the treatment of neuroinflammation-related brain diseases.
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Affiliation(s)
- Elisa Angeloni
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | - Lorenzo Germelli
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | - Laura Marchetti
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy; Center for Instrument Sharing University of Pisa (CISUP), Lungarno Pacinotti, 43/44, 56126 Pisa, Italy.
| | - Eleonora Da Pozzo
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy; Center for Instrument Sharing University of Pisa (CISUP), Lungarno Pacinotti, 43/44, 56126 Pisa, Italy.
| | - Chiara Tremolanti
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | - Christian H Wetzel
- Department of Psychiatry and Psychotherapy, Molecular Neurosciences, University of Regensburg, 93059 Regensburg, Germany.
| | - Emma Baglini
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | - Sabrina Taliani
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | - Federico Da Settimo
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | - Claudia Martini
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | - Barbara Costa
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy; Center for Instrument Sharing University of Pisa (CISUP), Lungarno Pacinotti, 43/44, 56126 Pisa, Italy.
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10
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Szego EM, Malz L, Bernhardt N, Rösen-Wolff A, Falkenburger BH, Luksch H. Constitutively active STING causes neuroinflammation and degeneration of dopaminergic neurons in mice. eLife 2022; 11:81943. [PMID: 36314770 PMCID: PMC9767458 DOI: 10.7554/elife.81943] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/31/2022] [Indexed: 12/30/2022] Open
Abstract
Stimulator of interferon genes (STING) is activated after detection of cytoplasmic dsDNA by cGAS (cyclic GMP-AMP synthase) as part of the innate immunity defence against viral pathogens. STING binds TANK-binding kinase 1 (TBK1). TBK1 mutations are associated with familial amyotrophic lateral sclerosis, and the STING pathway has been implicated in the pathogenesis of further neurodegenerative diseases. To test whether STING activation is sufficient to induce neurodegeneration, we analysed a mouse model that expresses the constitutively active STING variant N153S. In this model, we focused on dopaminergic neurons, which are particularly sensitive to stress and represent a circumscribed population that can be precisely quantified. In adult mice expressing N153S STING, the number of dopaminergic neurons was smaller than in controls, as was the density of dopaminergic axon terminals and the concentration of dopamine in the striatum. We also observed alpha-synuclein pathology and a lower density of synaptic puncta. Neuroinflammation was quantified by staining astroglia and microglia, by measuring mRNAs, proteins and nuclear translocation of transcription factors. These neuroinflammatory markers were already elevated in juvenile mice although at this age the number of dopaminergic neurons was still unaffected, thus preceding the degeneration of dopaminergic neurons. More neuroinflammatory markers were blunted in mice deficient for inflammasomes than in mice deficient for signalling by type I interferons. Neurodegeneration, however, was blunted in both mice. Collectively, these findings demonstrate that chronic activation of the STING pathway is sufficient to cause degeneration of dopaminergic neurons. Targeting the STING pathway could therefore be beneficial in Parkinson's disease and further neurodegenerative diseases.
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Affiliation(s)
- Eva M Szego
- Department of Neurology, TU Dresden, Dresden, Germany
| | - Laura Malz
- Departments of Neurology & Pediatrics, TU Dresden, Dresden, Germany
| | | | | | - Björn H Falkenburger
- Department of Neurology, TU Dresden, Dresden, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen, Dresden, Germany
| | - Hella Luksch
- Department of Pediatrics, TU Dresden, Dresden, Germany
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11
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Corsi F, Baglini E, Barresi E, Salerno S, Cerri C, Martini C, Da Settimo Passetti F, Taliani S, Gargini C, Piano I. Targeting TSPO Reduces Inflammation and Apoptosis in an In Vitro Photoreceptor-Like Model of Retinal Degeneration. ACS Chem Neurosci 2022; 13:3188-3197. [PMID: 36300862 PMCID: PMC9673150 DOI: 10.1021/acschemneuro.2c00582] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The 18 kDa translocator protein (TSPO) is predominantly located in the mitochondrial outer membrane, playing an important role in steroidogenesis, inflammation, survival, and cell proliferation. Its expression in the CNS, and mainly in glial cells, is upregulated in neuropathologies and brain injury. In this study, the potential of targeting TSPO for the therapeutic treatment of inflammatory-based retinal neurodegeneration was evaluated by means of an in vitro model of lipopolysaccharide (LPS)-induced degeneration in 661 W cells, a photoreceptor-like cell line. After the assessment of the expression of TSPO in 661W cells, which, to the best of our knowledge, was never investigated so far, the anti-inflammatory and cytoprotective effects of a number of known TSPO ligands, belonging to the class of N,N-dialkyl-2-arylindol-3-ylglyoxylamides (PIGAs), were evaluated, using the classic TSPO ligand PK11195 as the reference standard. All tested PIGAs showed the ability to modulate the inflammatory and apoptotic processes in 661 W photoreceptor-like cells and to reduce LPS-driven cellular cytotoxicity. The protective effect of PIGAs was, in all cases, reduced by cotreatment with the pregnenolone synthesis inhibitor SU-10603, suggesting the involvement of neurosteroids in the protective mechanism. As inflammatory processes play a crucial role in the retinal neurodegenerative disease progression toward photoreceptors' death and complete blindness, targeting TSPO might represent a successful strategy to slow down this degenerative process that may lead to the inexorable loss of vision.
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12
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Naoi M, Maruyama W, Shamoto-Nagai M. Neuroprotective Function of Rasagiline and Selegiline, Inhibitors of Type B Monoamine Oxidase, and Role of Monoamine Oxidases in Synucleinopathies. Int J Mol Sci 2022; 23:ijms231911059. [PMID: 36232361 PMCID: PMC9570229 DOI: 10.3390/ijms231911059] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/09/2022] [Accepted: 09/14/2022] [Indexed: 11/27/2022] Open
Abstract
Synucleinopathies are a group of neurodegenerative disorders caused by the accumulation of toxic species of α-synuclein. The common clinical features are chronic progressive decline of motor, cognitive, behavioral, and autonomic functions. They include Parkinson’s disease, dementia with Lewy body, and multiple system atrophy. Their etiology has not been clarified and multiple pathogenic factors include oxidative stress, mitochondrial dysfunction, impaired protein degradation systems, and neuroinflammation. Current available therapy cannot prevent progressive neurodegeneration and “disease-modifying or neuroprotective” therapy has been proposed. This paper presents the molecular mechanisms of neuroprotection by the inhibitors of type B monoamine oxidase, rasagiline and selegiline. They prevent mitochondrial apoptosis, induce anti-apoptotic Bcl-2 protein family, and pro-survival brain- and glial cell line-derived neurotrophic factors. They also prevent toxic oligomerization and aggregation of α-synuclein. Monoamine oxidase is involved in neurodegeneration and neuroprotection, independently of the catalytic activity. Type A monoamine oxidases mediates rasagiline-activated signaling pathways to induce neuroprotective genes in neuronal cells. Multi-targeting propargylamine derivatives have been developed for therapy in various neurodegenerative diseases. Preclinical studies have presented neuroprotection of rasagiline and selegiline, but beneficial effects have been scarcely presented. Strategy to improve clinical trials is discussed to achieve disease-modification in synucleinopathies.
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Affiliation(s)
- Makoto Naoi
- Correspondence: ; Tel.: +81-05-6173-1111 (ext. 3494); Fax: +81-561-731-142
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13
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Translocator Protein 18 kDa (TSPO) as a Novel Therapeutic Target for Chronic Pain. Neural Plast 2022; 2022:8057854. [PMID: 36071748 PMCID: PMC9444456 DOI: 10.1155/2022/8057854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 07/19/2022] [Accepted: 08/13/2022] [Indexed: 11/18/2022] Open
Abstract
Chronic pain is an enormous modern public health problem, with significant numbers of people debilitated by chronic pain from a variety of etiologies. Translocator protein 18 kDa (TSPO) was discovered in 1977 as a peripheral benzodiazepine receptor. It is a five transmembrane domain protein, mainly localized in the outer mitochondrial membrane. Recent and increasing studies have found changes in TSPO and its ligands in various chronic pain models. Reversing their expressions has been shown to alleviate chronic pain in these models, illustrating the effects of TSPO and its ligands. Herein, we review recent evidence and the mechanisms of TSPO in the development of chronic pain associated with peripheral nerve injury, spinal cord injury, cancer, and inflammatory responses. The cumulative evidence indicates that TSPO-based therapy may become an alternative strategy for treating chronic pain.
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14
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Viviano M, Barresi E, Siméon FG, Costa B, Taliani S, Da Settimo F, Pike VW, Castellano S. Essential Principles and Recent Progress in the Development of TSPO PET Ligands for Neuroinflammation Imaging. Curr Med Chem 2022; 29:4862-4890. [PMID: 35352645 PMCID: PMC10080361 DOI: 10.2174/0929867329666220329204054] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 12/21/2021] [Accepted: 01/25/2022] [Indexed: 11/22/2022]
Abstract
The translocator protein 18kDa (TSPO) is expressed in the outer mitochondrial membrane and is implicated in several functions, including cholesterol transport and steroidogenesis. Under normal physiological conditions, TSPO is present in very low concentrations in the human brain but is markedly upregulated in response to brain injury and inflammation. This upregulation is strongly associated with activated microglia. Therefore, TSPO is particularly suited for assessing active gliosis associated with brain lesions following injury or disease. For over three decades, TSPO has been studied as a biomarker. Numerous radioligands for positron emission tomography (PET) that target TSPO have been developed for imaging inflammatory progression in the brain. Although [11C]PK11195, the prototypical first-generation PET radioligand, is still widely used for in vivo studies, mainly now as its single more potent R-enantiomer, it has severe limitations, including low sensitivity and poor amenability to quantification. Second-generation radioligands are characterized by higher TSPO specific signals but suffer from other drawbacks, such as sensitivity to the TSPO single nucleotide polymorphism (SNP) rs6971. Therefore, their applications in human studies have the burden of needing to genotype subjects. Consequently, recent efforts are focused on developing improved radioligands that combine the optimal features of the second generation with the ability to overcome the differences in binding affinities across the population. This review presents essential principles in the design and development of TSPO PET ligands and discusses prominent examples among the main chemotypes.
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Affiliation(s)
- Monica Viviano
- Department of Pharmacy, University of Salerno, 84084 Fisciano (SA), Italy
| | | | - Fabrice G. Siméon
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Barbara Costa
- Department of Pharmacy, University of Pisa, 56126, Pisa, Italy
| | - Sabrina Taliani
- Department of Pharmacy, University of Pisa, 56126, Pisa, Italy
| | | | - Victor W. Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sabrina Castellano
- Department of Pharmacy, University of Salerno, 84084 Fisciano (SA), Italy
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15
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The mitochondrial translocator protein (TSPO): a key multifunctional molecule in the nervous system. Biochem J 2022; 479:1455-1466. [PMID: 35819398 DOI: 10.1042/bcj20220050] [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] [Received: 01/31/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 12/12/2022]
Abstract
Translocator protein (TSPO, 18 kDa), formerly known as peripheral benzodiazepine receptor, is an evolutionary well-conserved protein located on the outer mitochondrial membrane. TSPO is involved in a variety of fundamental physiological functions and cellular processes. Its expression levels are regulated under many pathological conditions, therefore, TSPO has been proposed as a tool for diagnostic imaging and an attractive therapeutic drug target in the nervous system. Several synthetic TSPO ligands have thus been explored as agonists and antagonists for innovative treatments as neuroprotective and regenerative agents. In this review, we provide state-of-the-art knowledge of TSPO functions in the brain and peripheral nervous system. Particular emphasis is placed on its contribution to important physiological functions such as mitochondrial homeostasis, energy metabolism and steroidogenesis. We also report how it is involved in neuroinflammation, brain injury and diseases of the nervous system.
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16
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Hines RM, Aquino EA, Khumnark MI, Dávila MP, Hines DJ. Comparative Assessment of TSPO Modulators on Electroencephalogram Activity and Exploratory Behavior. Front Pharmacol 2022; 13:750554. [PMID: 35444539 PMCID: PMC9015213 DOI: 10.3389/fphar.2022.750554] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 03/07/2022] [Indexed: 01/04/2023] Open
Abstract
Network communication in the CNS relies upon multiple neuronal and glial signaling pathways. In addition to synaptic transmission, other organelles such as mitochondria play roles in cellular signaling. One highly conserved mitochondrial signaling mechanism involves the 18 kDa translocator protein (TSPO) of the outer mitochondrial membrane. Originally, TSPO was identified as a binding site for benzodiazepines in the periphery. It was later discovered that TSPO is found in mitochondria, including in CNS cells. TSPO is implicated in multiple cellular processes, including the translocation of cholesterol and steroidogenesis, porphyrin transport, cellular responses to stress, inflammation, and tumor progression. Yet the impacts of modulating TSPO signaling on network activity and behavioral performance have not been characterized. In the present study, we assessed the effects of TSPO modulators PK11195, Ro5-4864, and XBD-173 via electroencephalography (EEG) and the open field test (OFT) at low to moderate doses. Cortical EEG recordings revealed increased power in the δ and θ frequency bands after administration of each of the three modulators, as well as compound- and dose-specific changes in α and γ. Behaviorally, these compounds reduced locomotor activity in the OFT in a dose-dependent manner, with XBD-173 having the subtlest behavioral effects while still strongly modulating the EEG. These findings indicate that TSPO modulators, despite their diversity, exert similar effects on the EEG while displaying a range of sedative/hypnotic effects at moderate to high doses. These findings bring us one step closer to understanding the functions of TSPO in the brain and as a target in CNS disease.
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Affiliation(s)
- Rochelle M Hines
- Department of Psychology, Psychological and Brain Sciences & Interdisciplinary Neuroscience Programs, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Elaine A Aquino
- Department of Psychology, Psychological and Brain Sciences & Interdisciplinary Neuroscience Programs, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Matthew I Khumnark
- Department of Psychology, Psychological and Brain Sciences & Interdisciplinary Neuroscience Programs, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Maria P Dávila
- Department of Psychology, Psychological and Brain Sciences & Interdisciplinary Neuroscience Programs, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Dustin J Hines
- Department of Psychology, Psychological and Brain Sciences & Interdisciplinary Neuroscience Programs, University of Nevada, Las Vegas, Las Vegas, NV, United States
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17
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Histamine Causes Pyroptosis of Liver by Regulating Gut-Liver Axis in Mice. Int J Mol Sci 2022; 23:ijms23073710. [PMID: 35409071 PMCID: PMC8998596 DOI: 10.3390/ijms23073710] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 03/24/2022] [Accepted: 03/24/2022] [Indexed: 02/05/2023] Open
Abstract
Huangjiu usually caused rapid-drunkenness and components such as β-benzyl ethanol (β-be), isopentanol (Iso), histamine (His), and phenethylamine (PEA) have been reported linked with intoxication. However, the destructive effect of these components on gut microbiota and liver is unclear. In this study, we found oral treatment of these components, especially His, stimulated the level of oxidative stress and inflammatory cytokines in liver and serum of mice. The gut microbiota community was changed and the level of lipopolysaccharide (LPS) increased significantly. Additionally, cellular pyroptosis pathway has been assessed and correlation analysis revealed a possible relationship between gut microbiota and liver pyroptosis. We speculated oral His treatment caused the reprogramming of gut microbiota metabolism, and increased LPS modulated the gut-liver interaction, resulting in liver pyroptosis, which might cause health risks. This study provided a theoretical basis for the effect of Huangjiu, facilitating the development of therapeutic and preventive strategies for related inflammatory disorders.
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18
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The 18 kDa translocator protein is associated with microglia in the hippocampus of non-demented elderly subjects. AGING BRAIN 2022; 2:100045. [PMID: 36908874 PMCID: PMC9997180 DOI: 10.1016/j.nbas.2022.100045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 06/22/2022] [Accepted: 06/24/2022] [Indexed: 11/23/2022] Open
Abstract
Increase in the brain expression of the 18 kDa translocator protein (TSPO) is considered as a marker of neuroinflammation in the context of brain diseases, such as Alzheimer's disease (AD). However, in non-demented subjects with Alzheimer's neuropathology, TSPO accumulation in hippocampus subdivisions has not been fully characterized. To determine if TSPO is associated with the presence of amyloid β plaques and/or phosphorylated Tau accumulation, we analyzed hippocampal sections using immunohistochemistry of 14 non-demented subjects with positive staining for Aβ and/or phosphorylated Tau. TSPO expression was heterogenous with higher accumulation in the CA2/3 and subiculum subfields of the hippocampus. Its distribution closely resembled that of the microglial IBA1 marker and of the Aβ42 amyloid form. In addition, positive correlations were observed between TSPO and IBA1 densities in CA4, CA2/3 and the subiculum but not with either the astrocyte GFAP marker or the AD-type Aβ and Tau markers. This study sustains the hypothesis that TSPO is mainly associated with microglia and in Aβ42-rich subdivisions in the hippocampus of non-demented elderly individuals.
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19
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Nutma E, Ceyzériat K, Amor S, Tsartsalis S, Millet P, Owen DR, Papadopoulos V, Tournier BB. Cellular sources of TSPO expression in healthy and diseased brain. Eur J Nucl Med Mol Imaging 2021; 49:146-163. [PMID: 33433698 PMCID: PMC8712293 DOI: 10.1007/s00259-020-05166-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/13/2020] [Indexed: 12/11/2022]
Abstract
The 18 kDa translocator protein (TSPO) is a highly conserved protein located in the outer mitochondrial membrane. TSPO binding, as measured with positron emission tomography (PET), is considered an in vivo marker of neuroinflammation. Indeed, TSPO expression is altered in neurodegenerative, neuroinflammatory, and neuropsychiatric diseases. In PET studies, the TSPO signal is often viewed as a marker of microglial cell activity. However, there is little evidence in support of a microglia-specific TSPO expression. This review describes the cellular sources and functions of TSPO in animal models of disease and human studies, in health, and in central nervous system diseases. A discussion of methods of analysis and of quantification of TSPO is also presented. Overall, it appears that the alterations of TSPO binding, their cellular underpinnings, and the functional significance of such alterations depend on many factors, notably the pathology or the animal model under study, the disease stage, and the involved brain regions. Thus, further studies are needed to fully determine how changes in TSPO binding occur at the cellular level with the ultimate goal of revealing potential therapeutic pathways.
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Affiliation(s)
- Erik Nutma
- Department of Pathology, Amsterdam UMC, VUmc, Amsterdam, The Netherlands
| | - Kelly Ceyzériat
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland
- Division of Nuclear medicine and Molecular Imaging, University Hospitals of Geneva, Geneva, Switzerland
- Division of Radiation Oncology, Department of Oncology, University Hospitals of Geneva, Geneva, Switzerland
| | - Sandra Amor
- Department of Pathology, Amsterdam UMC, VUmc, Amsterdam, The Netherlands
- Centre for Neuroscience and Trauma, Blizard Institute, Barts and the London School of Medicine & Dentistry, Queen Mary University of London, London, UK
| | - Stergios Tsartsalis
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland
- Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Philippe Millet
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland
- Department of Psychiatry, University of Geneva, Geneva, Switzerland
| | - David R Owen
- Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Vassilios Papadopoulos
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Benjamin B Tournier
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland.
- Department of Psychiatry, University of Geneva, Geneva, Switzerland.
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20
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Guilarte TR, Rodichkin AN, McGlothan JL, Acanda De La Rocha AM, Azzam DJ. Imaging neuroinflammation with TSPO: A new perspective on the cellular sources and subcellular localization. Pharmacol Ther 2021; 234:108048. [PMID: 34848203 DOI: 10.1016/j.pharmthera.2021.108048] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/04/2021] [Accepted: 11/24/2021] [Indexed: 12/14/2022]
Abstract
Translocator Protein 18 kDa (TSPO), previously named Peripheral Benzodiazepine Receptor, is a well-validated and widely used biomarker of neuroinflammation to assess diverse central nervous system (CNS) pathologies in preclinical and clinical studies. Many studies have shown that in animal models of human neurological and neurodegenerative disease and in the human condition, TSPO levels increase in the brain neuropil, and this increase is driven by infiltration of peripheral inflammatory cells and activation of glial cells. Therefore, a clear understanding of the dynamics of the cellular sources of the TSPO response is critically important in the interpretation of Positron Emission Tomography (PET) studies and for understanding the pathophysiology of CNS diseases. Within the normal brain compartment, there are tissues and cells such as the choroid plexus, ependymal cells of the lining of the ventricles, and vascular endothelial cells that also express TSPO at even higher levels than in glial cells. However, there is a paucity of knowledge if these cell types respond and increase TSPO in the diseased brain. These cells do provide a background signal that needs to be accounted for in TSPO-PET imaging studies. More recently, there are reports that TSPO may be expressed in neurons of the adult brain and TSPO expression may be increased by neuronal activity. Therefore, it is essential to study this topic with a great deal of detail, methodological rigor, and rule out alternative interpretations and imaging artifacts. High levels of TSPO are present in the outer mitochondrial membrane. Recent studies have provided evidence of its localization in other cellular compartments including the plasma membrane and perinuclear regions which may define functions that are different from that in mitochondria. A greater understanding of the TSPO subcellular localization in glial cells and infiltrating peripheral immune cells and associated function(s) may provide an additional layer of information to the understanding of TSPO neurobiology. This review is an effort to outline recent advances in understanding the cellular sources and subcellular localization of TSPO in brain cells and to examine remaining questions that require rigorous investigation.
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Affiliation(s)
- Tomás R Guilarte
- Brain, Behavior, & the Environment Program, Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL 33199, United States of America.
| | - Alexander N Rodichkin
- Brain, Behavior, & the Environment Program, Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL 33199, United States of America
| | - Jennifer L McGlothan
- Brain, Behavior, & the Environment Program, Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL 33199, United States of America
| | - Arlet Maria Acanda De La Rocha
- Brain, Behavior, & the Environment Program, Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL 33199, United States of America
| | - Diana J Azzam
- Brain, Behavior, & the Environment Program, Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL 33199, United States of America
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21
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The Neuro-Protective Effects of the TSPO Ligands CB86 and CB204 on 6-OHDA-Induced PC12 Cell Death as an In Vitro Model for Parkinson’s Disease. BIOLOGY 2021; 10:biology10111183. [PMID: 34827176 PMCID: PMC8615274 DOI: 10.3390/biology10111183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 11/21/2022]
Abstract
Simple Summary Aims and objectives: For this study, we hypothesized that the two TSPO ligands CB86 and CB204 can inhibit cellular apoptosis and necrosis by in in vitro cellular PD model of undifferentiated PC12 cells exposed to 6-hydroxydopamine (6-OHDA, 80 µM). The two TSPO ligands CB86 and CB204 seem to suppress cell death of PC12 induced by 6-OHDA. The results may be relevant to the use of these two TSPO ligands as therapeutic options for neurodegenerative diseases like Parkinson disease (PD). Results: The two ligands normalized significantly (57% and 52%, respectively, from 44%; whereas the control was 68%) cell proliferation at different time points from 0–24 h. As compared to control, the red count was increased up to 57-fold whereas CB86 and CB204 inhibited to 2.7-fold and 3.2-fold, respectively. CB86 and CB204 inhibited also normalized the cell viability up to 1.8-fold after the exposure to 6-OHDA, as assessed by XTT assay. The two TSPO ligands also inhibited apoptosis significantly (1.3-fold for both) as assessed by apopxin green staining. Conclusion: It appears that CB86, CB204, and maybe other TSPO ligands are able to slow the progression of neurodegenerative diseases like PD. Abstract Parkinson’s disease (PD) is a progressive neurodegenerative disorder which is characterized by the degeneration of dopaminergic neurons in substantia nigra (SN). Oxidative stress or reactive oxygen species (ROS) generation was suggested to play a role in this specific type of neurodegeneration. Therapeutic options which can target and counteract ROS generation may be of benefit. TSPO ligands are known to counteract with neuro-inflammation, ROS generation, apoptosis, and necrosis. In the current study, we investigated an in vitro cellular PD model by the assessment of 6-hydroxydopamine (6-OHDA, 80 µM)-induced PC12 neurotoxicity. Simultaneously to the exposure of the cells to 6-OHDA, we added the TSPO ligands CB86 and CB204 (25 µM each) and assessed the impact on several markers of cell death. The two ligands normalized significantly (57% and 52% respectively, from 44%; whereas the control was 68%) cell proliferation at different time points from 0–24 h. Additionally, we evaluated the effect of these two TSPO ligands on necrosis using propidium iodide (PI) staining and found that the ligands inhibited significantly the 6-OHDA-induced necrosis. As compared to control, the red count was increased up to 57-fold whereas CB86 and CB204 inhibited to 2.7-fold and 3.2-fold respectively. Necrosis was also analyzed by LDH assay which showed significant effect. Both assays demonstrated similar potent anti-necrotic effect of the two TSPO ligands. Reactive oxygen species (ROS) generation induced by 6-OHDA was also inhibited by the two TSPO ligand up to 1.3 and 1.5-fold respectively, as compared to 6-OHDA group. CB86 and CB204 inhibited also normalized the cell viability up to 1.8-fold after the exposure to 6-OHDA, as assessed by XTT assay. The two TSPO ligands also inhibited apoptosis significantly (1.3-fold for both) as assessed by apopxin green staining. In summary, it appears that the two TSPO ligands CB86 and CB204 can suppress cell death of PC12 induced by 6-OHDA. The results may be relevant to the use of these two TSPO ligands as therapeutic option neurodegenerative diseases like PD.
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22
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Wang J, Beecher K. TSPO: an emerging role in appetite for a therapeutically promising biomarker. Open Biol 2021; 11:210173. [PMID: 34343461 PMCID: PMC8331234 DOI: 10.1098/rsob.210173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
There is accumulating evidence that an obesogenic Western diet causes neuroinflammatory damage to the brain, which then promotes further appetitive behaviour. Neuroinflammation has been extensively studied by analysing the translocator protein of 18 kDa (TSPO), a protein that is upregulated in the inflamed brain following a damaging stimulus. As a result, there is a rich supply of TSPO-specific agonists, antagonists and positron emission tomography ligands. One TSPO ligand, etifoxine, is also currently used clinically for the treatment of anxiety with a minimal side-effect profile. Despite the neuroinflammatory pathogenesis of diet-induced obesity, and the translational potential of targeting TSPO, there is sparse literature characterizing the effect of TSPO on appetite. Therefore, in this review, the influence of TSPO on appetite is discussed. Three putative mechanisms for TSPO's appetite-modulatory effect are then characterized: the TSPO–allopregnanolone–GABAAR signalling axis, glucosensing in tanycytes and association with the synaptic protein RIM-BP1. We highlight that, in addition to its plethora of functions, TSPO is a regulator of appetite. This review ultimately suggests that the appetite-modulating function of TSPO should be further explored due to its potential therapeutic promise.
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Affiliation(s)
- Joshua Wang
- Addiction Neuroscience and Obesity Laboratory, School of Clinical Sciences, Faculty of Health, Translational Research Institute, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Kate Beecher
- Addiction Neuroscience and Obesity Laboratory, School of Clinical Sciences, Faculty of Health, Translational Research Institute, Queensland University of Technology, Brisbane, Queensland, Australia
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23
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Frison M, Faccenda D, Abeti R, Rigon M, Strobbe D, England-Rendon BS, Cash D, Barnes K, Sadeghian M, Sajic M, Wells LA, Xia D, Giunti P, Smith K, Mortiboys H, Turkheimer FE, Campanella M. The translocator protein (TSPO) is prodromal to mitophagy loss in neurotoxicity. Mol Psychiatry 2021; 26:2721-2739. [PMID: 33664474 PMCID: PMC8505241 DOI: 10.1038/s41380-021-01050-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 01/13/2021] [Accepted: 02/05/2021] [Indexed: 12/14/2022]
Abstract
Dysfunctional mitochondria characterise Parkinson's Disease (PD). Uncovering etiological molecules, which harm the homeostasis of mitochondria in response to pathological cues, is therefore pivotal to inform early diagnosis and therapy in the condition, especially in its idiopathic forms. This study proposes the 18 kDa Translocator Protein (TSPO) to be one of those. Both in vitro and in vivo data show that neurotoxins, which phenotypically mimic PD, increase TSPO to enhance cellular redox-stress, susceptibility to dopamine-induced cell death, and repression of ubiquitin-dependent mitophagy. TSPO amplifies the extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) signalling, forming positive feedback, which represses the transcription factor EB (TFEB) and the controlled production of lysosomes. Finally, genetic variances in the transcriptome confirm that TSPO is required to alter the autophagy-lysosomal pathway during neurotoxicity.
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Affiliation(s)
- Michele Frison
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London, United Kingdom
- MRC Mitochondrial Biology Unit, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Danilo Faccenda
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London, United Kingdom
| | - Rosella Abeti
- Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square London, United Kingdom
| | - Manuel Rigon
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London, United Kingdom
- Department of Biology, University of Rome TorVergata, Via della Ricerca Scientifica, Rome, Italy
| | - Daniela Strobbe
- Department of Biology, University of Rome TorVergata, Via della Ricerca Scientifica, Rome, Italy
| | - Britannie S England-Rendon
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London, United Kingdom
| | - Diana Cash
- Department of Neuroimaging, Institute of Psychiatry, King's College London, Camberwell, United Kingdom
| | - Katy Barnes
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - Mona Sadeghian
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Marija Sajic
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Lisa A Wells
- Imanova Limited, Centre for Imaging Sciences, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Dong Xia
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London, United Kingdom
| | - Paola Giunti
- Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square London, United Kingdom
| | - Kenneth Smith
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Heather Mortiboys
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - Federico E Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, King's College London, Camberwell, United Kingdom
| | - Michelangelo Campanella
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London, United Kingdom.
- Department of Biology, University of Rome TorVergata, Via della Ricerca Scientifica, Rome, Italy.
- University College London Consortium for Mitochondrial Research, London, United Kingdom.
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24
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Jung ME. A Protective Role of Translocator Protein in Alzheimer's Disease Brain. Curr Alzheimer Res 2021; 17:3-15. [PMID: 32065102 DOI: 10.2174/1567205017666200217105950] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 01/13/2020] [Accepted: 01/20/2020] [Indexed: 12/16/2022]
Abstract
Translocator Protein (18 kDa) (TSPO) is a mitochondrial protein that locates cytosol cholesterol to mitochondrial membranes to begin the synthesis of steroids including neurotrophic neurosteroids. TSPO is abundantly present in glial cells that support neurons and respond to neuroinflammation. Located at the outer membrane of mitochondria, TSPO regulates the opening of mitochondrial permeability transition pore (mPTP) that controls the entry of molecules necessary for mitochondrial function. TSPO is linked to neurodegenerative Alzheimer's Disease (AD) such that TSPO is upregulated in the brain of AD patients and signals AD-induced adverse changes in brain. The initial increase in TSPO in response to brain insults remains elevated to repair cellular damages and perhaps to prevent further neuronal degeneration as AD progresses. To exert such protective activities, TSPO increases the synthesis of neuroprotective steroids, decreases neuroinflammation, limits the opening of mPTP, and reduces the generation of reactive oxygen species. The beneficial effects of TSPO on AD brain are manifested as the attenuation of neurotoxic amyloid β and mitochondrial dysfunction accompanied by the improvement of memory and cognition. However, the protective activities of TSPO appear to be temporary and eventually diminish as the severity of AD becomes profound. Timely treatment with TSPO agonists/ligands before the loss of endogenous TSPO's activity may promote the protective functions and may extend neuronal survival.
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Affiliation(s)
- Marianna E Jung
- Pharmacology and Neuroscience, University of North Texas Health Science Center, Institute for Healthy Aging, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, United States
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25
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Fairley LH, Sahara N, Aoki I, Ji B, Suhara T, Higuchi M, Barron AM. Neuroprotective effect of mitochondrial translocator protein ligand in a mouse model of tauopathy. J Neuroinflammation 2021; 18:76. [PMID: 33740987 PMCID: PMC7980620 DOI: 10.1186/s12974-021-02122-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/02/2021] [Indexed: 12/13/2022] Open
Abstract
Background The translocator protein (TSPO) has been identified as a positron emission tomography (PET)-visible biomarker of inflammation and promising immunotherapeutic target for the treatment of Alzheimer’s disease (AD). While TSPO ligands have been shown to reduce the accumulation of the toxic Alzheimer’s beta-amyloid peptide, their effect on tau pathology has not yet been investigated. To address this, we analyzed the effects of TSPO ligand, Ro5-4864, on the progression of neuropathology in rTg4510 tau transgenic mice (TauTg). Methods Brain atrophy, tau accumulation, and neuroinflammation were assessed longitudinally using volumetric magnetic resonance imaging, tau-PET, and TSPO-PET, respectively. In vivo neuroimaging results were confirmed by immunohistochemistry for markers of neuronal survival (NeuN), tauopathy (AT8), and inflammation (TSPO, ionized calcium-binding adaptor molecule 1 or IBA-1, and complement component 1q or C1q) in brain sections from scanned mice. Results TSPO ligand treatment attenuated brain atrophy and hippocampal neuronal loss in the absence of any detected effect on tau depositions. Atrophy and neuronal loss were strongly associated with in vivo inflammatory signals measured by TSPO-PET, IBA-1, and levels of C1q, a regulator of the complement cascade. In vitro studies confirmed that the TSPO ligand Ro5-4864 reduces C1q expression in a microglial cell line in response to inflammation, reduction of which has been shown in previous studies to protect synapses and neurons in models of tauopathy. Conclusions These findings support a protective role for TSPO ligands in tauopathy, reducing neuroinflammation, neurodegeneration, and brain atrophy. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02122-1.
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Affiliation(s)
- Lauren H Fairley
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, 308232, Singapore
| | - Naruhiko Sahara
- National Institute of Radiological Science, Chiba City, Chiba Province, 263-8555, Japan
| | - Ichio Aoki
- National Institute of Radiological Science, Chiba City, Chiba Province, 263-8555, Japan
| | - Bin Ji
- National Institute of Radiological Science, Chiba City, Chiba Province, 263-8555, Japan
| | - Tetsuya Suhara
- National Institute of Radiological Science, Chiba City, Chiba Province, 263-8555, Japan
| | - Makoto Higuchi
- National Institute of Radiological Science, Chiba City, Chiba Province, 263-8555, Japan
| | - Anna M Barron
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, 308232, Singapore. .,National Institute of Radiological Science, Chiba City, Chiba Province, 263-8555, Japan.
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26
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Wang J, Li HY, Shen SY, Zhang JR, Liang LF, Huang HJ, Li B, Wu GC, Zhang YQ, Yu J. The antidepressant and anxiolytic effect of GPER on translocator protein (TSPO) via protein kinase a (PKA) signaling in menopausal female rats. J Steroid Biochem Mol Biol 2021; 207:105807. [PMID: 33345973 DOI: 10.1016/j.jsbmb.2020.105807] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 11/05/2020] [Accepted: 12/08/2020] [Indexed: 12/11/2022]
Abstract
Postmenopausal depression is mainly caused by the deprivation of ovarian hormones during menopausal transition, it is of great importance to study on the treatment that could effectively relieve symptoms of menopausal depression with fewer side effects. Activation of G-protein-coupled estrogen receptor (GPER) has long been reported to facilitate neuronal plasticity and improve cognition in animals. Meanwhile, it could participate in regulation of intracellular signaling pathways through the characteristic of GPER, ameliorate intracellular mitochondrial function and oxidative stress. However, the impact of GPER on regulating estrogen deprived-depressant and anxious behaviors is still largely unknown. Here we used the ovariectomized female rats to imitate the condition of menopause. Owing to the lateral ventricle administration of G-1 which specifically react with GPER receptor intracerebrally, Ovariectomized (OVX) female rats showed depressive- or anxiety-like phenotypes with attenuated mitochondrial function. In addition, G-1 facilitated PKA activation, which further accelerated TSPO phosphorylation and alleviated menopausal depression- and anxiety-like behaviors. Moreover, PKA inhibitor PKI could partially antagonized the anti-anxiety and anti-depression effects of G-1. Taken together, we concluded that GPER activation might exhibit antidepressant and anxiolytic effect by elevating TSPO phosphorylation via protein kinase A signaling and rescuing the redox status in menopausal female rats.
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Affiliation(s)
- Jing Wang
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Hao-Yuan Li
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Shi-Yu Shen
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Jia-Rui Zhang
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Ling-Feng Liang
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Hui-Jie Huang
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Bing Li
- Center Laboratories, Jinshan Hospital of Fudan University, Shanghai, 201508, China
| | - Gen-Cheng Wu
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Yu-Qiu Zhang
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
| | - Jin Yu
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
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27
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Fairley LH, Wong JH, Barron AM. Mitochondrial Regulation of Microglial Immunometabolism in Alzheimer's Disease. Front Immunol 2021; 12:624538. [PMID: 33717134 PMCID: PMC7947196 DOI: 10.3389/fimmu.2021.624538] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 01/21/2021] [Indexed: 12/14/2022] Open
Abstract
Alzheimer’s disease (AD) is an age-associated terminal neurodegenerative disease with no effective treatments. Dysfunction of innate immunity is implicated in the pathogenesis of AD, with genetic studies supporting a causative role in the disease. Microglia, the effector cells of innate immunity in the brain, are highly plastic and perform a diverse range of specialist functions in AD, including phagocytosing and removing toxic aggregates of beta amyloid and tau that drive neurodegeneration. These immune functions require high energy demand, which is regulated by mitochondria. Reflecting this, microglia have been shown to be highly metabolically flexible, reprogramming their mitochondrial function upon inflammatory activation to meet their energy demands. However, AD-associated genetic risk factors and pathology impair microglial metabolic programming, and metabolic derailment has been shown to cause innate immune dysfunction in AD. These findings suggest that immunity and metabolic function are intricately linked processes, and targeting microglial metabolism offers a window of opportunity for therapeutic treatment of AD. Here, we review evidence for the role of metabolic programming in inflammatory functions in AD, and discuss mitochondrial-targeted immunotherapeutics for treatment of the disease.
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Affiliation(s)
- Lauren H Fairley
- Neurobiology of Aging and Disease Laboratory, Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
| | - Jia Hui Wong
- Neurobiology of Aging and Disease Laboratory, Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
| | - Anna M Barron
- Neurobiology of Aging and Disease Laboratory, Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
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28
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Iliopoulou SM, Tsartsalis S, Kaiser S, Millet P, Tournier BB. Dopamine and Neuroinflammation in Schizophrenia - Interpreting the Findings from Translocator Protein (18kDa) PET Imaging. Neuropsychiatr Dis Treat 2021; 17:3345-3357. [PMID: 34819729 PMCID: PMC8608287 DOI: 10.2147/ndt.s334027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/09/2021] [Indexed: 12/22/2022] Open
Abstract
Schizophrenia is a complex disease whose pathophysiology is not yet fully understood. In addition to the long prevailing dopaminergic hypothesis, the evidence suggests that neuroinflammation plays a role in the pathophysiology of the disease. Recent studies using positron emission tomography (PET) that target a 18kDa translocator protein (TSPO) in activated microglial cells in an attempt to measure neuroinflammation in patients have shown a decrease or a lack of an increase in TSPO binding. Many biological and methodological considerations have been formulated to explain these findings. Although dopamine has been described as an immunomodulatory molecule, its potential role in neuroinflammation has not been explored in the aforementioned studies. In this review, we discuss the interactions between dopamine and neuroinflammation in psychotic states. Dopamine may inhibit neuroinflammation in activated microglia. Proinflammatory molecules released from microglia may decrease dopaminergic transmission. This could potentially explain why the levels of neuroinflammation in the brain of patients with schizophrenia seem to be unchanged or decreased compared to those in healthy subjects. However, most data are indirect and are derived from animal studies or from studies performed outside the field of schizophrenia. Further studies are needed to combine TSPO and dopamine imaging to study the association between microglial activation and dopamine system function.
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Affiliation(s)
- Sotiria Maria Iliopoulou
- Adult Psychiatry Division, Department of Psychiatry, Geneva University Hospitals (HUG), Geneva, 1225, Switzerland
| | | | - Stefan Kaiser
- Adult Psychiatry Division, Department of Psychiatry, Geneva University Hospitals (HUG), Geneva, 1225, Switzerland.,Faculty of Medicine, University of Geneva, Geneva, 1204, Switzerland
| | - Philippe Millet
- Adult Psychiatry Division, Department of Psychiatry, Geneva University Hospitals (HUG), Geneva, 1225, Switzerland.,Faculty of Medicine, University of Geneva, Geneva, 1204, Switzerland
| | - Benjamin B Tournier
- Adult Psychiatry Division, Department of Psychiatry, Geneva University Hospitals (HUG), Geneva, 1225, Switzerland.,Faculty of Medicine, University of Geneva, Geneva, 1204, Switzerland
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29
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Fan J, Papadopoulos V. Mitochondrial TSPO Deficiency Triggers Retrograde Signaling in MA-10 Mouse Tumor Leydig Cells. Int J Mol Sci 2020; 22:ijms22010252. [PMID: 33383772 PMCID: PMC7795497 DOI: 10.3390/ijms22010252] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 12/10/2020] [Accepted: 12/22/2020] [Indexed: 12/13/2022] Open
Abstract
The mitochondrial translocator protein (TSPO) has been shown to bind cholesterol with high affinity and is involved in mediating its availability for steroidogenesis. We recently reported that targeted Tspo gene deletion in MA-10 mouse tumor Leydig cells resulted in reduced cAMP-stimulated steroid formation and significant reduction in the mitochondrial membrane potential (ΔΨm) compared to control cells. We hypothesized that ΔΨm reduction in the absence of TSPO probably reflects the dysregulation and/or maintenance failure of some basic mitochondrial function(s). To explore the consequences of TSPO depletion via CRISPR-Cas9-mediated deletion (indel) mutation in MA-10 cells, we assessed the transcriptome changes in TSPO-mutant versus wild-type (Wt) cells using RNA-seq. Gene expression profiles were validated using real-time PCR. We report herein that there are significant changes in nuclear gene expression in Tspo mutant versus Wt cells. The identified transcriptome changes were mapped to several signaling pathways including the regulation of membrane potential, calcium signaling, extracellular matrix, and phagocytosis. This is a retrograde signaling pathway from the mitochondria to the nucleus and is probably the result of changes in expression of several transcription factors, including key members of the NF-κB pathway. In conclusion, TSPO regulates nuclear gene expression through intracellular signaling. This is the first evidence of a compensatory response to the loss of TSPO with transcriptome changes at the cellular level.
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Affiliation(s)
- Jinjiang Fan
- The Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada;
- Department of Medicine, McGill University, Montreal, QC H4A 3J1, Canada
| | - Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada;
- Department of Medicine, McGill University, Montreal, QC H4A 3J1, Canada
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089, USA
- Correspondence: ; Fax: +1-323-442-1681
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30
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Rivière G, Jaipuria G, Andreas LB, Leonov A, Giller K, Becker S, Zweckstetter M. Membrane-embedded TSPO: an NMR view. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2020; 50:173-180. [PMID: 33354729 PMCID: PMC8071791 DOI: 10.1007/s00249-020-01487-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 10/19/2020] [Accepted: 11/26/2020] [Indexed: 12/21/2022]
Abstract
Translocator Protein (18 kDa) (TSPO) is a mitochondrial transmembrane protein commonly used as a biomarker for neuroinflammation and is also a potential therapeutic target in neurodegenerative diseases. Despite intensive research efforts, the function of TSPO is still largely enigmatic. Deciphering TSPO structure in the native lipid environment is essential to gain insight into its cellular activities and to design improved diagnostic and therapeutic ligands. Here, we discuss the influence of lipid composition on the structure of mammalian TSPO embedded into lipid bilayers on the basis of solid-state NMR experiments. We further highlight that cholesterol can influence both the tertiary and quaternary TSPO structure and also influence TSPO localization in mitochondria-associated endoplasmic reticulum membranes.
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Affiliation(s)
- Gwladys Rivière
- Senior Research Group of Translational Structural Biology in Dementia, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | - Garima Jaipuria
- Senior Research Group of Translational Structural Biology in Dementia, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | - Loren B Andreas
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Andrei Leonov
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Karin Giller
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Stefan Becker
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Markus Zweckstetter
- Senior Research Group of Translational Structural Biology in Dementia, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany.
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany.
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.
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31
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Russi M, Martin E, D'Autréaux B, Tixier L, Tricoire H, Monnier V. A Drosophila model of Friedreich ataxia with CRISPR/Cas9 insertion of GAA repeats in the frataxin gene reveals in vivo protection by N-acetyl cysteine. Hum Mol Genet 2020; 29:2831-2844. [PMID: 32744307 DOI: 10.1093/hmg/ddaa170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/10/2020] [Accepted: 07/23/2020] [Indexed: 12/11/2022] Open
Abstract
Friedreich ataxia (FA) is caused by GAA repeat expansions in the first intron of FXN, the gene encoding frataxin, which results in decreased gene expression. Thanks to the high degree of frataxin conservation, the Drosophila melanogaster fruitfly appears as an adequate animal model to study this disease and to evaluate therapeutic interventions. Here, we generated a Drosophila model of FA with CRISPR/Cas9 insertion of approximately 200 GAA in the intron of the fly frataxin gene fh. These flies exhibit a developmental delay and lethality associated with decreased frataxin expression. We were able to bypass preadult lethality using genetic tools to overexpress frataxin only during the developmental period. These frataxin-deficient adults are short-lived and present strong locomotor defects. RNA-Seq analysis identified deregulation of genes involved in amino-acid metabolism and transcriptomic signatures of oxidative stress. In particular, we observed a progressive increase of Tspo expression, fully rescued by adult frataxin expression. Thus, Tspo expression constitutes a molecular marker of the disease progression in our fly model and might be of interest in other animal models or in patients. Finally, in a candidate drug screening, we observed that N-acetyl cysteine improved the survival, locomotor function, resistance to oxidative stress and aconitase activity of frataxin-deficient flies. Therefore, our model provides the opportunity to elucidate in vivo, the protective mechanisms of this molecule of therapeutic potential. This study also highlights the strength of the CRISPR/Cas9 technology to introduce human mutations in endogenous orthologous genes, leading to Drosophila models of human diseases with improved physiological relevance.
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Affiliation(s)
- Maria Russi
- Université de Paris, BFA Unit of Functional and Adaptative Biology, UMR 8251, CNRS, Paris F-75013, France
| | - Elodie Martin
- Université de Paris, BFA Unit of Functional and Adaptative Biology, UMR 8251, CNRS, Paris F-75013, France
| | - Benoit D'Autréaux
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette cedex 91198, France
| | - Laura Tixier
- Université de Paris, BFA Unit of Functional and Adaptative Biology, UMR 8251, CNRS, Paris F-75013, France
| | - Hervé Tricoire
- Université de Paris, BFA Unit of Functional and Adaptative Biology, UMR 8251, CNRS, Paris F-75013, France
| | - Véronique Monnier
- Université de Paris, BFA Unit of Functional and Adaptative Biology, UMR 8251, CNRS, Paris F-75013, France
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32
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Belloli S, Morari M, Murtaj V, Valtorta S, Moresco RM, Gilardi MC. Translation Imaging in Parkinson's Disease: Focus on Neuroinflammation. Front Aging Neurosci 2020; 12:152. [PMID: 32581765 PMCID: PMC7289967 DOI: 10.3389/fnagi.2020.00152] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 05/06/2020] [Indexed: 12/15/2022] Open
Abstract
Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the appearance of α-synuclein insoluble aggregates known as Lewy bodies. Neurodegeneration is accompanied by neuroinflammation mediated by cytokines and chemokines produced by the activated microglia. Several studies demonstrated that such an inflammatory process is an early event, and contributes to oxidative stress and mitochondrial dysfunctions. α-synuclein fibrillization and aggregation activate microglia and contribute to disease onset and progression. Mutations in different genes exacerbate the inflammatory phenotype in the monogenic compared to sporadic forms of PD. Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) with selected radiopharmaceuticals allow in vivo imaging of molecular modifications in the brain of living subjects. Several publications showed a reduction of dopaminergic terminals and dopamine (DA) content in the basal ganglia, starting from the early stages of the disease. Moreover, non-dopaminergic neuronal pathways are also affected, as shown by in vivo studies with serotonergic and glutamatergic radiotracers. The role played by the immune system during illness progression could be investigated with PET ligands that target the microglia/macrophage Translocator protein (TSPO) receptor. These agents have been used in PD patients and rodent models, although often without attempting correlations with other molecular or functional parameters. For example, neurodegeneration and brain plasticity can be monitored using the metabolic marker 2-Deoxy-2-[18F]fluoroglucose ([18F]-FDG), while oxidative stress can be probed using the copper-labeled diacetyl-bis(N-methyl-thiosemicarbazone) ([Cu]-ATSM) radioligand, whose striatal-specific binding ratio in PD patients seems to correlate with a disease rating scale and motor scores. Also, structural and functional modifications during disease progression may be evaluated by Magnetic Resonance Imaging (MRI), using different parameters as iron content or cerebral volume. In this review article, we propose an overview of in vivo clinical and non-clinical imaging research on neuroinflammation as an emerging marker of early PD. We also discuss how multimodal-imaging approaches could provide more insights into the role of the inflammatory process and related events in PD development.
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Affiliation(s)
- Sara Belloli
- Institute of Molecular Bioimaging and Physiology (IBFM), CNR, Milan, Italy.,Nuclear Medicine Department, San Raffaele Scientific Institute (IRCCS), Milan, Italy
| | - Michele Morari
- Section of Pharmacology, Department of Medical Sciences, National Institute for Neuroscience, University of Ferrara, Ferrara, Italy
| | - Valentina Murtaj
- Nuclear Medicine Department, San Raffaele Scientific Institute (IRCCS), Milan, Italy.,PhD Program in Neuroscience, School of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
| | - Silvia Valtorta
- Institute of Molecular Bioimaging and Physiology (IBFM), CNR, Milan, Italy.,Nuclear Medicine Department, San Raffaele Scientific Institute (IRCCS), Milan, Italy.,Medicine and Surgery Department, University of Milano-Bicocca, Milan, Italy
| | - Rosa Maria Moresco
- Institute of Molecular Bioimaging and Physiology (IBFM), CNR, Milan, Italy.,Nuclear Medicine Department, San Raffaele Scientific Institute (IRCCS), Milan, Italy.,Medicine and Surgery Department, University of Milano-Bicocca, Milan, Italy
| | - Maria Carla Gilardi
- Institute of Molecular Bioimaging and Physiology (IBFM), CNR, Milan, Italy.,Medicine and Surgery Department, University of Milano-Bicocca, Milan, Italy
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Wolf A, Herb M, Schramm M, Langmann T. The TSPO-NOX1 axis controls phagocyte-triggered pathological angiogenesis in the eye. Nat Commun 2020; 11:2709. [PMID: 32483169 PMCID: PMC7264151 DOI: 10.1038/s41467-020-16400-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 04/30/2020] [Indexed: 02/07/2023] Open
Abstract
Aberrant immune responses including reactive phagocytes are implicated in the etiology of age-related macular degeneration (AMD), a major cause of blindness in the elderly. The translocator protein (18 kDa) (TSPO) is described as a biomarker for reactive gliosis, but its biological functions in retinal diseases remain elusive. Here, we report that tamoxifen-induced conditional deletion of TSPO in resident microglia using Cx3cr1CreERT2:TSPOfl/fl mice or targeting the protein with the synthetic ligand XBD173 prevents reactivity of phagocytes in the laser-induced mouse model of neovascular AMD. Concomitantly, the subsequent neoangiogenesis and vascular leakage are prevented by TSPO knockout or XBD173 treatment. Using different NADPH oxidase-deficient mice, we show that TSPO is a key regulator of NOX1-dependent neurotoxic ROS production in the retina. These data define a distinct role for TSPO in retinal phagocyte reactivity and highlight the protein as a drug target for immunomodulatory and antioxidant therapies for AMD.
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Affiliation(s)
- Anne Wolf
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, D-50931, Cologne, Germany
| | - Marc Herb
- Institute for Medical Microbiology, Immunology and Hygiene, D-50931, Cologne, Germany
| | - Michael Schramm
- Institute for Medical Microbiology, Immunology and Hygiene, D-50931, Cologne, Germany
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, D-50931, Cologne, Germany.
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, D-50931, Cologne, Germany.
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34
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Lee Y, Park Y, Nam H, Lee JW, Yu SW. Translocator protein (TSPO): the new story of the old protein in neuroinflammation. BMB Rep 2020. [PMID: 31818362 PMCID: PMC6999824 DOI: 10.5483/bmbrep.2020.53.1.273] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Translocator protein (TSPO), also known as peripheral benzodiazepine receptor, is a transmembrane protein located on the outer mitochondria membrane (OMM) and mainly expressed in glial cells in the brain. Because of the close correlation of its expression level with neuropathology and therapeutic efficacies of several TSPO binding ligands under many neurological conditions, TSPO has been regarded as both biomarker and therapeutic target, and the biological functions of TSPO have been a major research focus. However, recent genetic studies with animal and cellular models revealed unexpected results contrary to the anticipated biological importance of TSPO and cast doubt on the action modes of the TSPO-binding drugs. In this review, we summarize recent controversial findings on the discrepancy between pharmacological and genetic studies of TSPO and suggest some future direction to understand this old and mysterious protein.
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Affiliation(s)
- Younghwan Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Youngjin Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Hyeri Nam
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Ji-Won Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Seong-Woon Yu
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea; Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
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35
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18-kDa translocator protein association complexes in the brain: From structure to function. Biochem Pharmacol 2020; 177:114015. [PMID: 32387458 DOI: 10.1016/j.bcp.2020.114015] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 05/04/2020] [Indexed: 12/14/2022]
Abstract
The outer mitochondrial membrane 18-kDa translocator protein (TSPO) is highly conserved in organisms of different species and ubiquitously expressed throughout tissues, including the nervous system. In the healthy adult brain, TSPO expression levels are low and promptly modulated under different pathological conditions, such as cancer, inflammatory states, and neurological and psychiatric disorders. Not surprisingly, several endogenous and synthetic molecules capable of binding TSPO have been proposed as drugs or diagnostic tools for brain diseases. The most studied biochemical function of TSPO is cholesterol translocation into mitochondria, which in turn affects the synthesis of steroids in the periphery and neurosteroids in the brain. In the last 30 years, roles for TSPO have also been suggested in other cellular processes, such as heme synthesis, apoptosis, autophagy, calcium signalling and reactive oxygen species production. Herein, we provide an overview of TSPO associations with different proteins, focusing particular attention on their related functions. Furthermore, recent TSPO-targeted therapeutic interventions are explored and discussed as prospect for innovative treatments in mental and brain diseases.
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36
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Dimitrova-Shumkovska J, Krstanoski L, Veenman L. Diagnostic and Therapeutic Potential of TSPO Studies Regarding Neurodegenerative Diseases, Psychiatric Disorders, Alcohol Use Disorders, Traumatic Brain Injury, and Stroke: An Update. Cells 2020; 9:cells9040870. [PMID: 32252470 PMCID: PMC7226777 DOI: 10.3390/cells9040870] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/29/2020] [Accepted: 03/30/2020] [Indexed: 02/08/2023] Open
Abstract
Neuroinflammation and cell death are among the common symptoms of many central nervous system diseases and injuries. Neuroinflammation and programmed cell death of the various cell types in the brain appear to be part of these disorders, and characteristic for each cell type, including neurons and glia cells. Concerning the effects of 18-kDa translocator protein (TSPO) on glial activation, as well as being associated with neuronal cell death, as a response mechanism to oxidative stress, the changes of its expression assayed with the aid of TSPO-specific positron emission tomography (PET) tracers' uptake could also offer evidence for following the pathogenesis of these disorders. This could potentially increase the number of diagnostic tests to accurately establish the stadium and development of the disease in question. Nonetheless, the differences in results regarding TSPO PET signals of first and second generations of tracers measured in patients with neurological disorders versus healthy controls indicate that we still have to understand more regarding TSPO characteristics. Expanding on investigations regarding the neuroprotective and healing effects of TSPO ligands could also contribute to a better understanding of the therapeutic potential of TSPO activity for brain damage due to brain injury and disease. Studies so far have directed attention to the effects on neurons and glia, and processes, such as death, inflammation, and regeneration. It is definitely worthwhile to drive such studies forward. From recent research it also appears that TSPO ligands, such as PK11195, Etifoxine, Emapunil, and 2-Cl-MGV-1, demonstrate the potential of targeting TSPO for treatments of brain diseases and disorders.
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Affiliation(s)
- Jasmina Dimitrova-Shumkovska
- Department of Experimental Biochemistry, Institute of Biology, Faculty of Natural Sciences and Mathematics, University Ss Cyril and Methodius, Arhimedova 3, P.O. Box 162, 1000 Skopje, Republic of North Macedonia;
- Correspondence: (J.D.-S.); (L.V.)
| | - Ljupcho Krstanoski
- Department of Experimental Biochemistry, Institute of Biology, Faculty of Natural Sciences and Mathematics, University Ss Cyril and Methodius, Arhimedova 3, P.O. Box 162, 1000 Skopje, Republic of North Macedonia;
| | - Leo Veenman
- Technion-Israel Institute of Technology, Faculty of Medicine, Rappaport Institute of Medical Research, 1 Efron Street, P.O. Box 9697, Haifa 31096, Israel
- Correspondence: (J.D.-S.); (L.V.)
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Tonon MC, Vaudry H, Chuquet J, Guillebaud F, Fan J, Masmoudi-Kouki O, Vaudry D, Lanfray D, Morin F, Prevot V, Papadopoulos V, Troadec JD, Leprince J. Endozepines and their receptors: Structure, functions and pathophysiological significance. Pharmacol Ther 2020; 208:107386. [DOI: 10.1016/j.pharmthera.2019.06.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/20/2019] [Indexed: 02/06/2023]
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38
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Betlazar C, Middleton RJ, Banati R, Liu GJ. The Translocator Protein (TSPO) in Mitochondrial Bioenergetics and Immune Processes. Cells 2020; 9:cells9020512. [PMID: 32102369 PMCID: PMC7072813 DOI: 10.3390/cells9020512] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 02/19/2020] [Accepted: 02/19/2020] [Indexed: 12/11/2022] Open
Abstract
The translocator protein (TSPO) is an outer mitochondrial membrane protein that is widely used as a biomarker of neuroinflammation, being markedly upregulated in activated microglia in a range of brain pathologies. Despite its extensive use as a target in molecular imaging studies, the exact cellular functions of this protein remain in question. The long-held view that TSPO plays a fundamental role in the translocation of cholesterol through the mitochondrial membranes, and thus, steroidogenesis, has been disputed by several groups with the advent of TSPO knockout mouse models. Instead, much evidence is emerging that TSPO plays a fundamental role in cellular bioenergetics and associated mitochondrial functions, also part of a greater role in the innate immune processes of microglia. In this review, we examine the more direct experimental literature surrounding the immunomodulatory effects of TSPO. We also review studies which highlight a more central role for TSPO in mitochondrial processes, from energy metabolism, to the propagation of inflammatory responses through reactive oxygen species (ROS) modulation. In this way, we highlight a paradigm shift in approaches to TSPO functioning.
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Affiliation(s)
- Calina Betlazar
- Human Health, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia; (R.J.M.); (R.B.)
- Discipline of Medical Imaging & Radiation Sciences, Faculty of Medicine and Health, Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, NSW 2050, Australia
- Correspondence: (C.B.); (G-J.L.)
| | - Ryan J. Middleton
- Human Health, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia; (R.J.M.); (R.B.)
| | - Richard Banati
- Human Health, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia; (R.J.M.); (R.B.)
- Discipline of Medical Imaging & Radiation Sciences, Faculty of Medicine and Health, Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, NSW 2050, Australia
| | - Guo-Jun Liu
- Human Health, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia; (R.J.M.); (R.B.)
- Discipline of Medical Imaging & Radiation Sciences, Faculty of Medicine and Health, Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, NSW 2050, Australia
- Correspondence: (C.B.); (G-J.L.)
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Hu S, Hu M, Liu J, Zhang B, Zhang Z, Zhou FH, Wang L, Dong J. Phosphorylation of Tau and α-Synuclein Induced Neurodegeneration in MPTP Mouse Model of Parkinson's Disease. Neuropsychiatr Dis Treat 2020; 16:651-663. [PMID: 32184604 PMCID: PMC7061418 DOI: 10.2147/ndt.s235562] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/09/2020] [Indexed: 12/17/2022] Open
Abstract
PURPOSE Parkinson's disease (PD) is the second most common neurodegenerative disease. The α-Synuclein is a major component of Lewy bodies and Lewy neurites, the pathologic hallmark of PD. It is known that α-Synuclein is phosphorylated (p-α-Synuclein) in PD and tau-hyperphosphorylation (p-Tau) is also a pathologic feature of PD. However, the relationship between p-Synuclein and p-Tau in PD is not clear, in particular in the MPTP model of PD. The purpose of this study was to reveal their relationship in the mouse MPTP model. METHODS Firstly, the p-α-Synuclein, α-Synuclein, p-Tau and Tau protein levels were analyzed. Then, GSK3β activation was determined using immunoblot and immunohistochemical staining. Finally, the dopaminergic neurodegeneration was assessed using Tyrosine Hydroxylase (TH) staining and retrograde labeling and microglial marker were labeled. Microglial activation and nigrostriatal pathway degeneration were observed. RESULTS The results showed that p-α-Synuclein, α-Synuclein, p-Tau and Tau were upregulated in both hippocampus and substantia nigra of the PD mouse model. Furthermore, p-α-Synuclein and p-Tau were localized in the same regions of substantial nigra (SN) and dentate gyrus (DG) of hippocampus (Hippo). The activated form of GSK3β (phosphor GSK3β Y216) was increased in multiple brain areas. The GSK3β inhibitor AZD1080 injected in MPTP mice suppressed the expression of p-Tau and p-GSK3β and improved motor functions. CONCLUSION These findings revealed that p-α-Synuclein and p-Tau proteins are key pathological events leading to neurodegeneration and motor dysfunctions in the mouse MPTP model of PD. Our data suggest that the interference with the GSK3β activity may be an effective approach for the treatment of PD.
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Affiliation(s)
- Shanshan Hu
- Good Clinical Practice Center, Affiliated Hospital of Zunyi Medical University, Zunyi 563003, Guizhou, People's Republic of China
| | - Meigui Hu
- The Second School of Clinical Medicine, Zhuhai Campus of Zunyi Medical University, Zhuhai 519041, Guangdong, People's Republic of China
| | - Jian Liu
- Department of Anatomy, Zunyi Medical University, Zunyi 563000, Guizhou, People's Republic of China
| | - Bei Zhang
- Department of Stomatology, The First People's Hospital of Zunyi, Zunyi 563099, Guizhou, People's Republic of China
| | - Zhen Zhang
- Department of Hand Surgery, Department of Plastic Reconstructive Surgery, Ningbo No. 6 Hospital, Ningbo 315040, People's Republic of China
| | - Fiona H Zhou
- School of Pharmacy and Medical Sciences, and UniSA Cancer Research Institute, University of South Australia, Adelaide, SA 5001, Australia
| | - Liping Wang
- Department of Hand Surgery, Department of Plastic Reconstructive Surgery, Ningbo No. 6 Hospital, Ningbo 315040, People's Republic of China.,School of Pharmacy and Medical Sciences, and UniSA Cancer Research Institute, University of South Australia, Adelaide, SA 5001, Australia
| | - Jianghui Dong
- Department of Hand Surgery, Department of Plastic Reconstructive Surgery, Ningbo No. 6 Hospital, Ningbo 315040, People's Republic of China.,School of Pharmacy and Medical Sciences, and UniSA Cancer Research Institute, University of South Australia, Adelaide, SA 5001, Australia
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40
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Klee K, Storti F, Barben M, Samardzija M, Langmann T, Dunaief J, Grimm C. Systemic knockout of Tspo in mice does not affect retinal morphology, function and susceptibility to degeneration. Exp Eye Res 2019; 188:107816. [PMID: 31562844 DOI: 10.1016/j.exer.2019.107816] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/19/2019] [Accepted: 09/24/2019] [Indexed: 12/11/2022]
Abstract
Translocator protein (18 kDa) (TSPO) is a mitochondrial protein expressed by reactive microglia and astrocytes at the site of neuronal injury. Although TSPO function has not been fully determined, synthetic TSPO ligands have beneficial effects on different pathologies of the central nervous system, including the retina. Here, we studied the pattern of Tspo expression in the aging human retina and in two mouse models of retinal degeneration. Using a newly generated Tspo-KO mouse, we investigated the impact of the lack of TSPO on retinal morphology, function and susceptibility to degeneration. We show that TSPO was expressed in both human and mouse retina and retinal pigment epithelium (RPE). Tspo was induced in the mouse retina upon degeneration, but constitutively expressed in the RPE. Similarly, TSPO expression levels in healthy human retina and RPE were not differentially regulated during aging. Tspo-KO mice had normal retinal morphology and function up to 48 weeks of age. Photoreceptor loss caused either by exposure to excessive light levels or by a mutation in the phosphodiesterase 6b gene was not affected by the absence of Tspo. The reactivity states of retinal mononuclear phagocytes following light-damage were comparable in Tspo-KO and control mice. Our data suggest that lack of endogenous TSPO does not directly influence the magnitude of photoreceptor degeneration or microglia activation in these two models of retinal degeneration. We therefore hypothesize that the interaction of TSPO with its ligands may be required to modulate disease progression.
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Affiliation(s)
- Katrin Klee
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland; Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Federica Storti
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland
| | - Maya Barben
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland
| | - Marijana Samardzija
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), Cologne, Germany
| | - Joshua Dunaief
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Christian Grimm
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland; Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland; Neuroscience Center, University of Zurich, Zurich, Switzerland.
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Jellinger KA. Animal models of synucleinopathies and how they could impact future drug discovery and delivery efforts. Expert Opin Drug Discov 2019; 14:969-982. [DOI: 10.1080/17460441.2019.1638908] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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42
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Inhibitory Effects of the Two Novel TSPO Ligands 2-Cl-MGV-1 and MGV-1 on LPS-induced Microglial Activation. Cells 2019; 8:cells8050486. [PMID: 31121852 PMCID: PMC6562711 DOI: 10.3390/cells8050486] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 05/16/2019] [Accepted: 05/17/2019] [Indexed: 02/06/2023] Open
Abstract
The 18 kDa translocator protein (TSPO) ligands 2-Cl-MGV-1 and MGV-1 can attenuate cell death of astrocyte-like cells (U118MG) and induce differentiation of neuronal progenitor cells (PC-12). Lipopolysaccharide (LPS) is a bacterial membrane endotoxin that activates cellular inflammatory pathways by releasing pro-inflammatory molecules, including cytokines and chemokines. The aim of the present study was to assess the immuno-modulatory effect of TSPO ligands in activated microglial cells. We demonstrated that the TSPO ligands 2-Cl-MGV-1 and MGV-1 can prevent LPS-induced activation of microglia (BV-2 cell line). Co-treatment of LPS (100 ng/mL) with these TSPO ligands (final concentration- 25 µM) reduces significantly the LPS-induced release of interleukin-6 (IL-6) from 16.9-fold to 2.5-fold, IL-β from 8.3-fold to 1.6-fold, interferon-γ from 16.0-fold to 2.2-fold, and tumor necrosis factor-α from 16.4-fold to 1.8-fold. This anti-inflammatory activity seems to be achieved by inhibition of NF-κB p65 activation. Assessment of initiation of ROS generation and cell metabolism shows significant protective effects of these two novel TSPO ligands. The IL-10 and IL-13 levels were not affected by any of the TSPO ligands. Thus, it appears that the ligands suppress the LPS-induced activation of some inflammatory responses of microglia. Such immunomodulatory effects may be relevant to the pharmacotherapy of neuro-inflammatory diseases.
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