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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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2
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Wongso H, Kurniawan A, Setiadi Y, Kusumaningrum CE, Widyasari EM, Wibawa TH, Mahendra I, Febrian MB, Sriyani ME, Halimah I, Daruwati I, Gunawan R, Achmad A, Nugraha DH, Lesmana R, Nugraha AS. Translocator Protein 18 kDa (TSPO): A Promising Molecular Target for Image-Guided Surgery of Solid Cancers. Adv Pharm Bull 2024; 14:86-104. [PMID: 38585455 PMCID: PMC10997928 DOI: 10.34172/apb.2024.015] [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: 05/01/2023] [Revised: 08/26/2023] [Accepted: 10/08/2023] [Indexed: 04/09/2024] Open
Abstract
The translocator protein 18-kDa (TSPO) is a mitochondrial membrane protein that is previously identified as the peripheral benzodiazepine receptor (PBR). Furthermore, it plays a significant role in a diverse range of biochemical processes, including steroidogenesis, mitochondrial cholesterol transport, cell survival and death, cell proliferation, and carcinogenesis. Several investigations also reported its roles in various types of cancers, including colorectal, brain, breast, prostate, and lung cancers, as well as melanoma. According to a previous study, the expression of TSPO was upregulated in cancer cells, which corresponds to an aggressive phenotype and/or poor prognosis. Consequently, the potential for crafting diagnostic and prognostic tools with a focus on TSPO holds great potential. In this context, several radioligands designed to target this protein have been identified, and some of the candidates have advanced to clinical trials. In recent years, the use of hybrid probes with radioactive and fluorescence molecules for image-guided surgery has exhibited promising results in animal and human studies. This indicates that the approach can serve as a valuable surgical navigator during cancer surgery. The current hybrid probes are built from various molecular platforms, including small molecules, nanoparticles, and antibodies. Although several TSPO-targeted imaging probes have been developed, their development for image-guided surgery of cancers is still limited. Therefore, this review aims to highlight recent findings on the involvement of TSPO in carcinogenesis, as well as provide a new perspective on the potential application of TSPO-targeted hybrid probes for image-guided surgery.
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Affiliation(s)
- Hendris Wongso
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
| | - Ahmad Kurniawan
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Yanuar Setiadi
- Research Center for Environmental and Clean Technology, Research Organization for Life Sciences and Environment, National Research and Innovation Agency, Puspiptek, Banten 15314, Indonesia
| | - Crhisterra E. Kusumaningrum
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Eva M. Widyasari
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Teguh H.A. Wibawa
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Isa Mahendra
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
| | - Muhamad B. Febrian
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Maula E. Sriyani
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Iim Halimah
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Isti Daruwati
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
- Department of Pharmaceutical Analysis and Medicinal Chemistry, Faculty of Pharmacy, Universitas Padjadjaran, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
| | - Rudi Gunawan
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
- Department of Pharmaceutical Analysis and Medicinal Chemistry, Faculty of Pharmacy, Universitas Padjadjaran, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
| | - Arifudin Achmad
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
- Department of Nuclear Medicine and Molecular Theranostics, Faculty of Medicine, Universitas Padjadjaran, Bandung 40161
- Oncology and Stem Cells Working Group, Faculty of Medicine, Universitas Padjadjaran, Bandung 40161
| | | | - Ronny Lesmana
- Department of Biomedical Science, Faculty of Medicine, Universitas Padjadjaran, Jatinangor 45363, Indonesia
- Physiology Molecular, Division of Biological Activity, Central Laboratory, Universitas Padjadjaran, Jatinangor 45363, Indonesia
- Laboratory of Sciences, Graduate School, Universitas Padjadjaran, Bandung, Indonesia
| | - Ari S. Nugraha
- Drug Utilisation and Discovery Research Group, Faculty of Pharmacy, Universitas Jember, Jember 68121, Indonesia
- School of Chemistry and Molecular Biosciences, Molecular Horizons, University of Wollongong, Wollongong, New South Wales, 2522, Australia
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Nutma E, Fancy N, Weinert M, Tsartsalis S, Marzin MC, Muirhead RCJ, Falk I, Breur M, de Bruin J, Hollaus D, Pieterman R, Anink J, Story D, Chandran S, Tang J, Trolese MC, Saito T, Saido TC, Wiltshire KH, Beltran-Lobo P, Phillips A, Antel J, Healy L, Dorion MF, Galloway DA, Benoit RY, Amossé Q, Ceyzériat K, Badina AM, Kövari E, Bendotti C, Aronica E, Radulescu CI, Wong JH, Barron AM, Smith AM, Barnes SJ, Hampton DW, van der Valk P, Jacobson S, Howell OW, Baker D, Kipp M, Kaddatz H, Tournier BB, Millet P, Matthews PM, Moore CS, Amor S, Owen DR. Translocator protein is a marker of activated microglia in rodent models but not human neurodegenerative diseases. Nat Commun 2023; 14:5247. [PMID: 37640701 PMCID: PMC10462763 DOI: 10.1038/s41467-023-40937-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 08/16/2023] [Indexed: 08/31/2023] Open
Abstract
Microglial activation plays central roles in neuroinflammatory and neurodegenerative diseases. Positron emission tomography (PET) targeting 18 kDa Translocator Protein (TSPO) is widely used for localising inflammation in vivo, but its quantitative interpretation remains uncertain. We show that TSPO expression increases in activated microglia in mouse brain disease models but does not change in a non-human primate disease model or in common neurodegenerative and neuroinflammatory human diseases. We describe genetic divergence in the TSPO gene promoter, consistent with the hypothesis that the increase in TSPO expression in activated myeloid cells depends on the transcription factor AP1 and is unique to a subset of rodent species within the Muroidea superfamily. Finally, we identify LCP2 and TFEC as potential markers of microglial activation in humans. These data emphasise that TSPO expression in human myeloid cells is related to different phenomena than in mice, and that TSPO-PET signals in humans reflect the density of inflammatory cells rather than activation state.
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Affiliation(s)
- Erik Nutma
- Department of Pathology, Amsterdam UMC - Location VUmc, Amsterdam, The Netherlands
- Department of Neurobiology and Aging, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Nurun Fancy
- Department of Brain Sciences, Imperial College London, London, UK
- UK Dementia Research Institute at Imperial College London, London, UK
| | - Maria Weinert
- Department of Brain Sciences, Imperial College London, London, UK
| | - Stergios Tsartsalis
- Department of Brain Sciences, Imperial College London, London, UK
- UK Dementia Research Institute at Imperial College London, London, UK
- Department of Psychiatry, University of Geneva, Geneva, Switzerland
| | - Manuel C Marzin
- Department of Pathology, Amsterdam UMC - Location VUmc, Amsterdam, The Netherlands
| | - Robert C J Muirhead
- Department of Brain Sciences, Imperial College London, London, UK
- UK Dementia Research Institute at Imperial College London, London, UK
| | - Irene Falk
- Viral Immunology Section, NIH, Bethesda, MD, USA
- Flow and Imaging Cytometry Core Facility, NIH, Bethesda, MD, USA
| | - Marjolein Breur
- Department of Pathology, Amsterdam UMC - Location VUmc, Amsterdam, The Netherlands
| | - Joy de Bruin
- Department of Pathology, Amsterdam UMC - Location VUmc, Amsterdam, The Netherlands
| | - David Hollaus
- Department of Pathology, Amsterdam UMC - Location VUmc, Amsterdam, The Netherlands
| | - Robin Pieterman
- Department of Pathology, Amsterdam UMC - Location VUmc, Amsterdam, The Netherlands
| | - Jasper Anink
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - David Story
- UK Dementia Research Institute at Edinburgh, Edinburgh, UK
| | | | - Jiabin Tang
- Department of Brain Sciences, Imperial College London, London, UK
- UK Dementia Research Institute at Imperial College London, London, UK
| | - Maria C Trolese
- Department of Neuroscience, Mario Negri Institute for Pharmacological Research IRCCS, Milan, Italy
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, Wako-shi, Saitama, Japan
| | - Takaomi C Saido
- Department of Neurocognitive Science, Institute of Brain Science, Nagoya City University, Nagoya, Japan
| | | | - Paula Beltran-Lobo
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Alexandra Phillips
- Department of Brain Sciences, Imperial College London, London, UK
- UK Dementia Research Institute at Imperial College London, London, UK
| | - Jack Antel
- Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Luke Healy
- Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Marie-France Dorion
- Division of Biomedical Sciences, Memorial University of Newfoundland, St. John's, Canada
| | - Dylan A Galloway
- Division of Biomedical Sciences, Memorial University of Newfoundland, St. John's, Canada
| | - Rochelle Y Benoit
- Division of Biomedical Sciences, Memorial University of Newfoundland, St. John's, Canada
| | - Quentin Amossé
- Department of Psychiatry, University of Geneva, Geneva, Switzerland
| | - Kelly Ceyzériat
- Department of Psychiatry, University of Geneva, Geneva, Switzerland
| | | | - Enikö Kövari
- Department of Psychiatry, University of Geneva, Geneva, Switzerland
| | - Caterina Bendotti
- Department of Neuroscience, Mario Negri Institute for Pharmacological Research IRCCS, Milan, Italy
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Carola I Radulescu
- Department of Brain Sciences, Imperial College London, London, UK
- UK Dementia Research Institute at Imperial College London, London, UK
| | - 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
| | - Amy M Smith
- UK Dementia Research Institute at Imperial College London, London, UK
- Centre for Brain Research and Department of Pharmacology and Clinical Pharmacology, University of Auckland, Auckland, New Zealand
| | - Samuel J Barnes
- Department of Brain Sciences, Imperial College London, London, UK
- UK Dementia Research Institute at Imperial College London, London, UK
| | | | - Paul van der Valk
- Department of Pathology, Amsterdam UMC - Location VUmc, Amsterdam, The Netherlands
| | | | - Owain W Howell
- Institute of Life Science (ILS), Swansea University Medical School, Swansea, UK
| | - David Baker
- Department of Neuroscience and Trauma, Blizard Institute, Queen Mary University of London, London, UK
| | - Markus Kipp
- Institute of Anatomy, Rostock University Medical Center, 18057, Rostock, Germany
| | - Hannes Kaddatz
- Institute of Anatomy, Rostock University Medical Center, 18057, Rostock, Germany
| | | | - Philippe Millet
- Department of Psychiatry, University of Geneva, Geneva, Switzerland
- Division of Adult Psychiatry, University Hospitals of Geneva, Geneva, Switzerland
| | - Paul M Matthews
- Department of Brain Sciences, Imperial College London, London, UK
- UK Dementia Research Institute at Imperial College London, London, UK
| | - Craig S Moore
- Division of Biomedical Sciences, Memorial University of Newfoundland, St. John's, Canada
| | - Sandra Amor
- Department of Pathology, Amsterdam UMC - Location VUmc, Amsterdam, The Netherlands.
- Department of Neuroscience and Trauma, Blizard Institute, Queen Mary University of London, London, UK.
- Institute of Anatomy, Rostock University Medical Center, 18057, Rostock, Germany.
| | - David R Owen
- Department of Brain Sciences, Imperial College London, London, UK.
- UK Dementia Research Institute at Imperial College London, London, UK.
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Cvetanovic M, Gray M. Contribution of Glial Cells to Polyglutamine Diseases: Observations from Patients and Mouse Models. Neurotherapeutics 2023; 20:48-66. [PMID: 37020152 PMCID: PMC10119372 DOI: 10.1007/s13311-023-01357-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/17/2023] [Indexed: 04/07/2023] Open
Abstract
Neurodegenerative diseases are broadly characterized neuropathologically by the degeneration of vulnerable neuronal cell types in a specific brain region. The degeneration of specific cell types has informed on the various phenotypes/clinical presentations in someone suffering from these diseases. Prominent neurodegeneration of specific neurons is seen in polyglutamine expansion diseases including Huntington's disease (HD) and spinocerebellar ataxias (SCA). The clinical manifestations observed in these diseases could be as varied as the abnormalities in motor function observed in those who have Huntington's disease (HD) as demonstrated by a chorea with substantial degeneration of striatal medium spiny neurons (MSNs) or those with various forms of spinocerebellar ataxia (SCA) with an ataxic motor presentation primarily due to degeneration of cerebellar Purkinje cells. Due to the very significant nature of the degeneration of MSNs in HD and Purkinje cells in SCAs, much of the research has centered around understanding the cell autonomous mechanisms dysregulated in these neuronal cell types. However, an increasing number of studies have revealed that dysfunction in non-neuronal glial cell types contributes to the pathogenesis of these diseases. Here we explore these non-neuronal glial cell types with a focus on how each may contribute to the pathogenesis of HD and SCA and the tools used to evaluate glial cells in the context of these diseases. Understanding the regulation of supportive and harmful phenotypes of glia in disease could lead to development of novel glia-focused neurotherapeutics.
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Affiliation(s)
- Marija Cvetanovic
- Department of Neuroscience, Institute for Translational Neuroscience, University of Minnesota, Minneapolis, USA
| | - Michelle Gray
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, USA.
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Molecular Characterization and Functional Analysis of Two Steroidogenic Genes TSPO and SMAD4 in Yellow Catfish. Int J Mol Sci 2021; 22:ijms22094505. [PMID: 33925909 PMCID: PMC8123483 DOI: 10.3390/ijms22094505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/22/2021] [Accepted: 04/22/2021] [Indexed: 11/16/2022] Open
Abstract
The steroid hormones are required for gonadal development in fish. The present study was undertaken to characterize the cDNA and promoter sequences of TSPO and SMAD4 genes in yellow catfish Pelteobagrus fulvidraco, explored the mRNA tissue expression and deciphered their promoter regions. Yellow catfish TSPO and SMAD4 shared the similar domains to the corresponding genes from other vertebrates. The TSPO and SMAD4 mRNAs were widely expressed in the detected tissues, but at different levels. Several transcription factors were predicted, such as Sp, GATA, AP1, SOX1, SRY, STAT, HNF4α, PPARγ, Pu.1 and FOXL2. PPARγ overexpression increased but STAT3 overexpression reduced TSPO promoter activity, and FOXL2 overexpression inhibited the promoter activity of TSPO and SMAD4. The site mutation and EMSA analysis indicated that TSPO promoter possessed STAT3 and FOXL2 sites. Overall, our provided the novel understanding into the transcriptionally regulatory mechanisms of TSPO and SMAD4 in fish.
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De Carvalho LM, Wiers CE, Sun H, Wang G, Volkow ND. Increased transcription of TSPO, HDAC2, and HDAC6 in the amygdala of males with alcohol use disorder. Brain Behav 2021; 11:e01961. [PMID: 33216461 PMCID: PMC7882159 DOI: 10.1002/brb3.1961] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 10/22/2020] [Accepted: 10/26/2020] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION Repeated exposure to high doses of alcohol triggers neuroinflammatory processes that contribute to craving and mood dysfunction in alcohol use disorder (AUD). The upregulation of the translocator protein (TSPO) is considered a biomarker of neuroinflammation, and TSPO ligands have been used as neuroimaging biomarkers of neuroinflammation. Epigenetic mechanisms are also implicated in neuroinflammatory responses to alcohol, and elevated expression of HDAC2 and HDAC6 has been reported in the brain of animals exposed to chronic alcohol. METHODS The present study examined the transcriptional regulation of TSPO, HDAC2, and HDAC6 in human postmortem brain tissue from males previously diagnosed with AUD (n = 11) compared to age-matched nondependent males (n = 13) in four brain regions relevant to AUD: prefrontal cortex (PFC), nucleus accumbens (NAc), hippocampus (HPP), and amygdala (AMY). RESULTS Translocator protein mRNA levels in AMY and PFC and HDAC2 and HDAC6 mRNA levels in AMY were upregulated in AUD compared to controls. In AMY, TSPO mRNA levels were positively associated with HDAC2 and HDAC6 mRNA levels, suggesting a possible regulation of TSPO by HDAC2 and HDAC6 in this brain region. In contrast, there were no group differences for TSPO, HDAC2, and HDAC6 in NAc and HPP. CONCLUSION Our study is the first to find upregulated TSPO mRNA levels in AMY and PFC in postmortem brains from AUD consistent with neuroinflammation, and in the amygdala, they implicate epigenetic regulation of TSPO by HDAC2 and HDAC6.
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Affiliation(s)
- Luana Martins De Carvalho
- National Institute on Alcohol Abuse and AlcoholismNational Institutes of HealthBethesdaMDUSA
- Center for Alcohol Research in Epigenetics, Department of PsychiatryUniversity of Illinois at ChicagoChicagoILUSA
| | - Corinde E. Wiers
- National Institute on Alcohol Abuse and AlcoholismNational Institutes of HealthBethesdaMDUSA
- Department of PsychiatryPerelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Hui Sun
- National Institute on Alcohol Abuse and AlcoholismNational Institutes of HealthBethesdaMDUSA
| | - Gene‐Jack Wang
- National Institute on Alcohol Abuse and AlcoholismNational Institutes of HealthBethesdaMDUSA
| | - Nora D. Volkow
- National Institute on Alcohol Abuse and AlcoholismNational Institutes of HealthBethesdaMDUSA
- National Institute on Drug AbuseNational Institutes of HealthRockvilleMDUSA
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Kikutani K, Giga H, Hosokawa K, Shime N, Aizawa H. Microglial translocator protein and stressor-related disorder. Neurochem Int 2020; 140:104855. [PMID: 32980493 DOI: 10.1016/j.neuint.2020.104855] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 09/20/2020] [Accepted: 09/22/2020] [Indexed: 02/08/2023]
Abstract
Despite the prevalence of neuroinflammation in psychiatric disorders, molecular mechanism underlying it remains elusive. Translocator protein 18 kDa (TSPO), also known as peripheral benzodiazepine receptor, is a mitochondrial protein implicated in the synthesis of steroids in a variety of tissues. Multiple reports have shown increased expression of TSPO in the activated microglia in the CNS. Radioactive probes targeting TSPO have been developed and used for imaging assessment in neurological and psychiatric disorders to examine neuroinflammation. Recent studies revealed that the wide range of stressors ranging from psychological to physical insults induced TSPO in human, suggesting that this protein could be an important tool to explore the contribution of microglia in stressor-related disorders. In this review, we first overview the microglial activation with TSPO in a wide range of stressors in human and animal models to discuss prevalent roles of TSPO in response of CNS to stressors. With recent update of the signaling pathway revealing link connecting TSPO with neuroinflammatory effectors such as reactive oxygen species, we discuss TSPO as a therapeutic targeting tool for suppression of adverse effect of stressors on long-lasting changes in animal behaviors and activities. Targeting TSPO which mediates neuroinflammation under the stress might pave the way to develop therapeutic intervention and prophylaxis of stressor-related disorder.
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Affiliation(s)
- Kazuya Kikutani
- Department of Emergency and Critical Care Medicine, Graduate School of Biomedical and Health Science, Hiroshima University, Japan
| | - Hiroshi Giga
- Department of Emergency and Critical Care Medicine, Graduate School of Biomedical and Health Science, Hiroshima University, Japan
| | - Koji Hosokawa
- Department of Emergency and Critical Care Medicine, Graduate School of Biomedical and Health Science, Hiroshima University, Japan
| | - Nobuaki Shime
- Department of Emergency and Critical Care Medicine, Graduate School of Biomedical and Health Science, Hiroshima University, Japan
| | - Hidenori Aizawa
- Department of Neurobiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Japan.
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Wilton DK, Stevens B. The contribution of glial cells to Huntington's disease pathogenesis. Neurobiol Dis 2020; 143:104963. [PMID: 32593752 DOI: 10.1016/j.nbd.2020.104963] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 05/07/2020] [Accepted: 06/10/2020] [Indexed: 12/20/2022] Open
Abstract
Glial cells play critical roles in the normal development and function of neural circuits, but in many neurodegenerative diseases, they become dysregulated and may contribute to the development of brain pathology. In Huntington's disease (HD), glial cells both lose normal functions and gain neuropathic phenotypes. In addition, cell-autonomous dysfunction elicited by mutant huntingtin (mHTT) expression in specific glial cell types is sufficient to induce both pathology and Huntington's disease-related impairments in motor and cognitive performance, suggesting that these cells may drive the development of certain aspects of Huntington's disease pathogenesis. In support of this imaging studies in pre-symptomatic HD patients and work on mouse models have suggested that glial cell dysfunction occurs at a very early stage of the disease, prior to the onset of motor and cognitive deficits. Furthermore, selectively ablating mHTT from specific glial cells or correcting for HD-induced changes in their transcriptional profile rescues some HD-related phenotypes, demonstrating the potential of targeting these cells for therapeutic intervention. Here we review emerging research focused on understanding the involvement of different glial cell types in specific aspects of HD pathogenesis. This work is providing new insight into how HD impacts biological functions of glial cells in the healthy brain as well as how HD induced dysfunction in these cells might change the way they integrate into biological circuits.
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Affiliation(s)
- Daniel K Wilton
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Beth Stevens
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Stanley Center, Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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Rashid K, Verhoyen M, Taiwo M, Langmann T. Translocator protein (18 kDa) (TSPO) ligands activate Nrf2 signaling and attenuate inflammatory responses and oxidative stress in human retinal pigment epithelial cells. Biochem Biophys Res Commun 2020; 528:261-268. [PMID: 32482385 DOI: 10.1016/j.bbrc.2020.05.114] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 05/17/2020] [Indexed: 01/31/2023]
Abstract
Degeneration of the retinal pigment epithelium (RPE) is a hallmark of atrophic age-related macular degeneration (AMD). Microglia mediated inflammatory responses and oxidative stress are critical pathophysiological processes in the onset and progression of RPE degeneration. Given the central role of the RPE, strategies to protect these cells from damage caused by oxidative stress and inflammation present a promising therapeutic approach to mitigate AMD. Ligands for the translocator protein (18 kDa) (TSPO) have been shown to confer protection against retinal inflammatory responses and neurodegeneration by acting primarily through retinal glia. However, despite RPE cells demonstrating strong TSPO expression, it remains unclear whether TSPO ligands could also inhibit inflammatory responses of RPE cells. Here, we investigated the influence of three different TSPO ligands XBD173, PK11195 and Ro5-4864 on inflammatory responses in human ARPE-19 cells triggered by supernatants from reactive human microglial cells and the lysosomal destabilizer, LLOMe. Our findings revealed that TSPO ligands significantly inhibited proinflammatory gene expression, inflammasome-mediated caspase-1 activation, lipid accumulation and intracellular ROS levels in stressed ARPE-19 cells. Notably, TSPO ligands induced activation of Nrf2 pathway and its downstream regulated genes in ARPE-19 cells, with Hmox-1 being the most strongly upregulated gene. Collectively, our study indicates that TSPO ligands can enhance the Nrf2 antioxidant pathway in RPE cells and protect them from cellular damage resulting from inflammation and oxidative stress.
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Affiliation(s)
- Khalid Rashid
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany.
| | - Mathilde Verhoyen
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany; University of Namur, Faculty of Medicine, Biomedical Sciences Department, 61 -5000, Namur, Belgium.
| | - Moyinoluwa Taiwo
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany.
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), 50931, Cologne, Germany.
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Fan Z, Kong M, Li M, Hong W, Fan X, Xu Y. Brahma Related Gene 1 (Brg1) Regulates Cellular Cholesterol Synthesis by Acting as a Co-factor for SREBP2. Front Cell Dev Biol 2020; 8:259. [PMID: 32500071 PMCID: PMC7243037 DOI: 10.3389/fcell.2020.00259] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 03/27/2020] [Indexed: 12/30/2022] Open
Abstract
Hepatocyte is a hub for cholesterol metabolism. Augmented synthesis of cholesterol in the liver is associated with hypercholesterolemia and contributes to the pathogenesis of a host of cardiovascular and metabolic diseases. Sterol response element binding protein 2 (SREBP2) regulates hepatic cholesterol metabolism by activating the transcription of rate-limiting enzymes in the cholesterol biosynthesis pathway. The underlying epigenetic mechanism is not well understood. We report here that mice with hepatocyte-specific knockout (CKO) of Brg1, a chromatin remodeling protein, exhibit reduced levels of hepatic cholesterol compared to the wild type (WT) littermates when placed on a high-fact diet (HFD) or a methionine-and-choline-deficient diet (MCD). Down-regulation of cholesterol levels as a result of BRG1 deficiency was accompanied by attenuation of cholesterogenic gene transcription. Likewise, BRG1 knockdown in hepatocytes markedly suppressed the induction of cholesterogenic genes by lipid depletion formulas. Brg1 interacted with SREBP2 and was recruited by SREBP2 to the cholesterogenic gene promoters. Reciprocally, Brg1 deficiency dampened the occupancies of SREBP2 on target promoters likely through modulating H3K9 methylation on the cholesterogenic gene promoters. Mechanistically, Brg1 recruited the H3K9 methyltransferase KDM3A to co-regulate pro-cholesterogenic transcription. KDM3A silencing dampened the cholesterogenic response in hepatocytes equivalent to Brg1 deficiency. In conclusion, our data demonstrate a novel epigenetic pathway that contributes to SREBP2-dependent cholesterol synthesis in hepatocytes.
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Affiliation(s)
- Zhiwen Fan
- Department of Pathology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Ming Kong
- Key Laboratory of Targeted Intervention of Cardiovascular Disease and Collaborative Innovation Center for Cardiovascular Translational Medicine, Department of Pathophysiology, Nanjing Medical University, Nanjing, China
| | - Min Li
- Department of Clinical Medicine and Laboratory Center for Experimental Medicine, Jiangsu Health Vocational College, Nanjing, China
| | - Wenxuan Hong
- Key Laboratory of Targeted Intervention of Cardiovascular Disease and Collaborative Innovation Center for Cardiovascular Translational Medicine, Department of Pathophysiology, Nanjing Medical University, Nanjing, China
| | - Xiangshan Fan
- Department of Pathology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Yong Xu
- Key Laboratory of Targeted Intervention of Cardiovascular Disease and Collaborative Innovation Center for Cardiovascular Translational Medicine, Department of Pathophysiology, Nanjing Medical University, Nanjing, China.,Institute of Biomedical Research, Liaocheng University, Liaocheng, China
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Shimoyama S, Furukawa T, Ogata Y, Nikaido Y, Koga K, Sakamoto Y, Ueno S, Nakamura K. Lipopolysaccharide induces mouse translocator protein (18 kDa) expression via the AP-1 complex in the microglial cell line, BV-2. PLoS One 2019; 14:e0222861. [PMID: 31536603 PMCID: PMC6752844 DOI: 10.1371/journal.pone.0222861] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 09/09/2019] [Indexed: 02/06/2023] Open
Abstract
It has been reported that neuroinflammation occurs in the central nervous system (CNS) in patients with neuropathic pain, Alzheimer’s disease and autism spectrum disorder. The 18-kDa translocator protein TSPO is used as an imaging target in positron emission tomography to detect neuroinflammation, and its expression is correlated with microglial activation. However, the mechanism underlying the transcriptional regulation of Tspo induced by inflammation is not clear. Here, we revealed that lipopolysaccharide (LPS) -induced Tspo expression was activated by the AP-1 complex in a mouse microglial cell line, BV-2. Knockdown of c-Fos and c-Jun, the components of AP-1, reduced LPS-induced Tspo expression. Furthermore, the enrichment of Sp1 in the proximal promoter region of Tspo was increased in the presence of LPS. In addition, the binding of histone deacetylase 1 (HDAC1) to the enhancer region, which contains the AP-1 site, was decreased by LPS treatment, but there were no significant differences in HDAC1 binding to the proximal promoter region with or without LPS. These results indicated that HDAC1 is involved not in the proximal promoter region but in the enhancer region. Our study revealed that inflammatory signals induce the recruitment of AP-1 to the enhancer region and Sp1 to the proximal promoter region of the Tspo gene and that Sp1 may regulate the basal expression of Tspo.
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Affiliation(s)
- Shuji Shimoyama
- Research Center for Child Mental Development, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Tomonori Furukawa
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Yoshiki Ogata
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Yoshikazu Nikaido
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Kohei Koga
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Yui Sakamoto
- Department of Neuropsychiatry, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Shinya Ueno
- Research Center for Child Mental Development, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Kazuhiko Nakamura
- Research Center for Child Mental Development, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
- Department of Neuropsychiatry, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
- * E-mail:
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Shoshan-Barmatz V, Pittala S, Mizrachi D. VDAC1 and the TSPO: Expression, Interactions, and Associated Functions in Health and Disease States. Int J Mol Sci 2019; 20:ijms20133348. [PMID: 31288390 PMCID: PMC6651789 DOI: 10.3390/ijms20133348] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 12/12/2022] Open
Abstract
The translocator protein (TSPO), located at the outer mitochondrial membrane (OMM), serves multiple functions and contributes to numerous processes, including cholesterol import, mitochondrial metabolism, apoptosis, cell proliferation, Ca2+ signaling, oxidative stress, and inflammation. TSPO forms a complex with the voltage-dependent anion channel (VDAC), a protein that mediates the flux of ions, including Ca2+, nucleotides, and metabolites across the OMM, controls metabolism and apoptosis and interacts with many proteins. This review focuses on the two OMM proteins TSPO and VDAC1, addressing their structural interaction and associated functions. TSPO appears to be involved in the generation of reactive oxygen species, proposed to represent the link between TSPO activation and VDAC, thus playing a role in apoptotic cell death. In addition, expression of the two proteins in healthy brains and diseased states is considered, as is the relationship between TSPO and VDAC1 expression. Both proteins are over-expressed in in brains from Alzheimer’s disease patients. Finally, TSPO expression levels were proposed as a biomarker of some neuropathological settings, while TSPO-interacting ligands have been considered as a potential basis for drug development.
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Affiliation(s)
- Varda Shoshan-Barmatz
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
| | - Srinivas Pittala
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Dario Mizrachi
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA
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