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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; 224:120-131. [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] [MESH Headings] [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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2
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Bréhat J, Issop L, Morin D. History of Tspo deletion and induction in vivo: Phenotypic outcomes under physiological and pathological situations. Biochimie 2024; 224:80-90. [PMID: 38432291 DOI: 10.1016/j.biochi.2024.03.001] [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: 12/21/2023] [Revised: 02/23/2024] [Accepted: 03/01/2024] [Indexed: 03/05/2024]
Abstract
The mitochondrial translocator protein (TSPO) is an outer mitochondrial protein membrane with high affinity for cholesterol. It is expressed in most tissues but is more particularly enriched in steroidogenic tissues. TSPO is involved in various biological mechanisms and TSPO regulation has been related to several diseases. However, despite a considerable number of published studies interested in TSPO over the past forty years, the precise function of the protein remains obscure. Most of the functions attributed to TSPO have been identified using pharmacological ligands of this protein, leading to much debate about the accuracy of these findings. In addition, research on the physiological role of TSPO has been hampered by the lack of in vivo deletion models. Studies to perform genetic deletion of Tspo in animal models have long been unsuccessful, which led to the conclusions that the deletion was deleterious and the gene essential to life. During the last decades, thanks to the significant technical advances allowing genome modification, several models of animal genetically modified for TSPO have been developed. These models have modified our view regarding TSPO and profoundly improved our fundamental knowledge on this protein. However, to date, they did not allow to elucidate the precise molecular function of TSPO and numerous questions persist concerning the physiological role of TSPO and its future as a therapeutic target. This article chronologically reviews the development of deletion and induction models of TSPO.
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Affiliation(s)
- Juliette Bréhat
- INSERM U955-IMRB, Team Ghaleh, UPEC, Ecole Nationale Vétérinaire d'Alfort, Créteil, France
| | - Leeyah Issop
- INSERM U955-IMRB, Team Ghaleh, UPEC, Ecole Nationale Vétérinaire d'Alfort, Créteil, France
| | - Didier Morin
- INSERM U955-IMRB, Team Ghaleh, UPEC, Ecole Nationale Vétérinaire d'Alfort, Créteil, France.
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3
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Papageorgiou MP, Filiou MD. Mitochondrial dynamics and psychiatric disorders: The missing link. Neurosci Biobehav Rev 2024; 165:105837. [PMID: 39089419 DOI: 10.1016/j.neubiorev.2024.105837] [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: 04/29/2024] [Revised: 07/14/2024] [Accepted: 07/29/2024] [Indexed: 08/04/2024]
Abstract
Elucidating the molecular mechanisms of psychopathology is crucial for optimized diagnosis and treatment. Accumulating data have underlined how mitochondrial bioenergetics affect major psychiatric disorders. However, how mitochondrial dynamics, a term addressing mitochondria quality control, including mitochondrial fission, fusion, biogenesis and mitophagy, is implicated in psychopathologies remains elusive. In this review, we summarize the existing literature on mitochondrial dynamics perturbations in psychiatric disorders/neuropsychiatric phenotypes. We include preclinical/clinical literature on mitochondrial dynamics recalibrations in anxiety, depression, post-traumatic stress disorder (PTSD), bipolar disorder and schizophrenia. We discuss alterations in mitochondrial network, morphology and shape, molecular markers of the mitochondrial dynamics machinery and mitochondrial DNA copy number (mtDNAcn) in animal models and human cohorts in brain and peripheral material. By looking for common altered mitochondrial dynamics patterns across diagnoses/phenotypes, we highlight mitophagy and biogenesis as regulators of anxiety and depression pathophysiology, respectively, as well as the fusion mediator dynamin-like 120 kDa protein (Opa1) as a molecular hub contributing to psychopathology. Finally, we comment on limitations and future directions in this novel neuropsychiatry field.
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Affiliation(s)
- Maria P Papageorgiou
- Laboratory of Biochemistry, Department of Biological Applications and Technology, University of Ioannina, Greece; Biomedical Research Institute, Foundation for Research and Technology-Hellas, Ioannina, Greece.
| | - Michaela D Filiou
- Laboratory of Biochemistry, Department of Biological Applications and Technology, University of Ioannina, Greece; Biomedical Research Institute, Foundation for Research and Technology-Hellas, Ioannina, Greece; Institute of Biosciences, University of Ioannina, Greece.
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Riebel M, Brunner LM, Nothdurfter C, Wein S, Schwarzbach J, Liere P, Schumacher M, Rupprecht R. Neurosteroids and translocator protein 18 kDa (TSPO) ligands as novel treatment options in depression. Eur Arch Psychiatry Clin Neurosci 2024:10.1007/s00406-024-01843-7. [PMID: 38976049 DOI: 10.1007/s00406-024-01843-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Accepted: 06/06/2024] [Indexed: 07/09/2024]
Abstract
Recently, the gamma-aminobutyric acid (GABA) system has come into focus for the treatment of anxiety, postpartum depression, and major depressive disorder. Endogenous 3α-reduced steroids such as allopregnanolone are potent positive allosteric modulators of GABAA receptors and have been known for decades. Current industry developments and first approvals by the U.S. food and drug administration (FDA) for the treatment of postpartum depression with exogenous analogues of these steroids represent a major step forward in the field. 3α-reduced steroids target both synaptic and extrasynaptic GABAA receptors, unlike benzodiazepines, which bind to synaptic receptors. The first FDA-approved 3α-reduced steroid for postpartum depression is brexanolone, an intravenous formulation of allopregnanolone. It has been shown to provide rapid relief of depressive symptoms. An orally available 3α-reduced steroid is zuranolone, which also received FDA approval in 2023 for the treatment of postpartum depression. Although a number of studies have been conducted, the efficacy data were not sufficient to achieve approval of zuranolone in major depressive disorder by the FDA in 2023. The most prominent side effects of these 3α-reduced steroids are somnolence, dizziness and headache. In addition to the issue of efficacy, it should be noted that current data limit the use of these compounds to two weeks. An alternative to exogenous 3α-reduced steroids may be the use of substances that induce endogenous neurosteroidogenesis, such as the translocator protein 18 kDa (TSPO) ligand etifoxine. TSPO has been extensively studied for its role in steroidogenesis, in addition to other functions such as anti-inflammatory and neuroregenerative properties. Currently, etifoxine is the only clinically available TSPO ligand in France for the treatment of anxiety disorders. Studies are underway to evaluate its antidepressant potential. Hopefully, neurosteroid research will lead to the development of fast-acting antidepressants.
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Affiliation(s)
- Marco Riebel
- Department of Psychiatry and Psychotherapy, University Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany.
| | - Lisa-Marie Brunner
- Department of Psychiatry and Psychotherapy, University Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany
| | - Caroline Nothdurfter
- Department of Psychiatry and Psychotherapy, University Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany
| | - Simon Wein
- Department of Psychiatry and Psychotherapy, University Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany
| | - Jens Schwarzbach
- Department of Psychiatry and Psychotherapy, University Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany
| | - Philippe Liere
- U1195 Inserm and University Paris-Saclay, Le Kremlin-Bicêtre, Paris, 94276, France
| | - Michael Schumacher
- U1195 Inserm and University Paris-Saclay, Le Kremlin-Bicêtre, Paris, 94276, France
| | - Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, University Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany
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Brunner LM, Riebel M, Wein S, Koller M, Zeman F, Huppertz G, Emmer T, Eberhardt Y, Schwarzbach J, Rupprecht R, Nothdurfter C. The translocator protein 18kDa ligand etifoxine in the treatment of depressive disorders-a double-blind, randomized, placebo-controlled proof-of-concept study. Trials 2024; 25:274. [PMID: 38650030 PMCID: PMC11034134 DOI: 10.1186/s13063-024-08120-x] [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: 01/19/2024] [Accepted: 04/16/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND Recent developments suggest that neurosteroids may achieve rapid antidepressant effects. As such, neurosteroidogenesis mediated by the translocator protein 18 kDa (TSPO) might constitute a promising option for the treatment of depression. Therefore, the current clinical trial aims to get the first evidence of whether TPSO ligands promote rapid antidepressant effects. Furthermore, we study which mechanisms of action, e.g., modulation of distinct neuronal networks, neurosteroidogenesis, endocrinological mechanisms, TSPO expression or microbiome composition, contribute to their putative antidepressant effects. METHODS This is a randomized, placebo-controlled, double-blind single-center trial of 2-week treatment with the TSPO ligand etifoxine versus placebo in depressive patients. Main eligibility criteria: male or female individuals aged 18 to 65 years with unipolar/bipolar depressive disorder with no other psychiatric main diagnosis or acute neurological/somatic disorder or drug/alcohol dependence during their lifetime. The primary endpoint is the time point at which 50% of the maximal effect has occurred (ET50) estimated by the scores of the Hamilton Depression Scale (HAMD-21). A total of 20 patients per group are needed to detect changes of therapeutic efficacy about 5% and changes of ET50 about 10% with a power of 70%. Assuming a drop-out rate of 10-20%, 50 patients will be randomized in total. The study will be conducted at the Department of Psychiatry and Psychotherapy of the University of Regensburg. DISCUSSION This study will provide a first proof-of-concept on the potential of the TSPO ligand etifoxine in the treatment of depressive disorders. TRIAL REGISTRATION Clinical Trials Register (EudraCT number: 2021-006773-38 , registration date: 14 September 2022) and German Register of Clinical Studies (DRKS number: DRKS00031099 , registration date: 23 January 2023).
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Affiliation(s)
- Lisa-Marie Brunner
- Department of Psychiatry and Psychotherapy, University of Regensburg, Regensburg, Germany.
| | - Marco Riebel
- Department of Psychiatry and Psychotherapy, University of Regensburg, Regensburg, Germany
| | - Simon Wein
- Department of Psychiatry and Psychotherapy, University of Regensburg, Regensburg, Germany
| | - Michael Koller
- Center for Clinical Studies, University Hospital of Regensburg, Regensburg, Germany
| | - Florian Zeman
- Center for Clinical Studies, University Hospital of Regensburg, Regensburg, Germany
| | - Gunnar Huppertz
- Center for Clinical Studies, University Hospital of Regensburg, Regensburg, Germany
| | - Tanja Emmer
- Center for Clinical Studies, University Hospital of Regensburg, Regensburg, Germany
| | - Yvonne Eberhardt
- Center for Clinical Studies, University Hospital of Regensburg, Regensburg, Germany
| | - Jens Schwarzbach
- Department of Psychiatry and Psychotherapy, University of Regensburg, Regensburg, Germany
| | - Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, University of Regensburg, Regensburg, Germany
| | - Caroline Nothdurfter
- Department of Psychiatry and Psychotherapy, University of Regensburg, Regensburg, Germany
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Pradhan AK, Neumüller T, Klug C, Fuchs S, Schlegel M, Ballmann M, Tartler KJ, Pianos A, Garcia MS, Liere P, Schumacher M, Kreuzer M, Rupprecht R, Rammes G. Chronic administration of XBD173 ameliorates cognitive deficits and neuropathology via 18 kDa translocator protein (TSPO) in a mouse model of Alzheimer's disease. Transl Psychiatry 2023; 13:332. [PMID: 37891168 PMCID: PMC10611770 DOI: 10.1038/s41398-023-02630-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/02/2023] [Accepted: 10/06/2023] [Indexed: 10/29/2023] Open
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of β-amyloid peptide (Aβ). It affects cognition and leads to memory impairment. The mitochondrial translocator protein (TSPO) plays an essential role in maintaining mitochondrial homeostasis and has been implicated in several neuronal disorders or neuronal injuries. Ligands targeting the mitochondrial translocator protein (18 kDa), promote neurosteroidogenesis and may be neuroprotective. To study whether the TSPO ligand XBD173 may exert early neuroprotective effects in AD pathology we investigated the impact of XBD173 on amyloid toxicity and neuroplasticity in mouse models of AD. We show that XBD173 (emapunil), via neurosteroid-mediated signaling and delta subunit-containing GABAA receptors, prevents the neurotoxic effect of Aβ on long-term potentiation (CA1-LTP) in the hippocampus and prevents the loss of spines. Chronic but not acute administration of XBD173 ameliorates spatial learning deficits in transgenic AD mice with arctic mutation (ArcAβ). The heterozygous TSPO-knockout crossed with the transgenic arctic mutation model of AD mice (het TSPOKO X ArcAβ) treated with XBD173 does not show this improvement in spatial learning suggesting TSPO is needed for procognitive effects of XBD173. The neuroprotective profile of XBD173 in AD pathology is further supported by a reduction in plaques and soluble Aβ levels in the cortex, increased synthesis of neurosteroids, rescued spine density, reduction of complement protein C1q deposits, and reduced astrocytic phagocytosis of functional synapses both in the hippocampus and cortex. Our findings suggest that XBD173 may exert therapeutic effects via TSPO in a mouse model of AD.
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Affiliation(s)
- Arpit Kumar Pradhan
- Klinik für Anaesthesiologie und Intensivmedizin der Technischen Universität München, Klinikum rechts der Isar, Munich, Germany.
- Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universität München, Martinsried, Germany.
| | - Tatjana Neumüller
- Klinik für Anaesthesiologie und Intensivmedizin der Technischen Universität München, Klinikum rechts der Isar, Munich, Germany
| | - Claudia Klug
- Klinik für Anaesthesiologie und Intensivmedizin der Technischen Universität München, Klinikum rechts der Isar, Munich, Germany
| | - Severin Fuchs
- Klinik für Anaesthesiologie und Intensivmedizin der Technischen Universität München, Klinikum rechts der Isar, Munich, Germany
| | - Martin Schlegel
- Klinik für Anaesthesiologie und Intensivmedizin der Technischen Universität München, Klinikum rechts der Isar, Munich, Germany
| | - Markus Ballmann
- Klinik für Anaesthesiologie und Intensivmedizin der Technischen Universität München, Klinikum rechts der Isar, Munich, Germany
| | - Katharina Johanna Tartler
- Klinik für Anaesthesiologie und Intensivmedizin der Technischen Universität München, Klinikum rechts der Isar, Munich, Germany
| | - Antoine Pianos
- U1195 Inserm and University Paris-Saclay, 80 rue du Général Leclerc, Le Kremlin-Bicêtre, 94276, France
| | - Maria Sanchez Garcia
- U1195 Inserm and University Paris-Saclay, 80 rue du Général Leclerc, Le Kremlin-Bicêtre, 94276, France
| | - Philippe Liere
- U1195 Inserm and University Paris-Saclay, 80 rue du Général Leclerc, Le Kremlin-Bicêtre, 94276, France
| | - Michael Schumacher
- U1195 Inserm and University Paris-Saclay, 80 rue du Général Leclerc, Le Kremlin-Bicêtre, 94276, France
| | - Matthias Kreuzer
- Klinik für Anaesthesiologie und Intensivmedizin der Technischen Universität München, Klinikum rechts der Isar, Munich, Germany
| | - Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, University Regensburg, Regensburg, Germany
| | - Gerhard Rammes
- Klinik für Anaesthesiologie und Intensivmedizin der Technischen Universität München, Klinikum rechts der Isar, Munich, Germany
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7
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Rupprecht R, Pradhan AK, Kufner M, Brunner LM, Nothdurfter C, Wein S, Schwarzbach J, Puig X, Rupprecht C, Rammes G. Neurosteroids and translocator protein 18 kDa (TSPO) in depression: implications for synaptic plasticity, cognition, and treatment options. Eur Arch Psychiatry Clin Neurosci 2023; 273:1477-1487. [PMID: 36574032 DOI: 10.1007/s00406-022-01532-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 11/30/2022] [Indexed: 12/28/2022]
Abstract
There is need for novel fast acting treatment options in affective disorders. 3α-reduced neurosteroids such as allopregnanolone are powerful positive allosteric modulators of GABAA receptors and target also extrasynaptic receptors. Their synthesis is mediated by the translocator protein 18 kDa (TSPO). TSPO ligands not only promote endogenous neurosteroidogenesis, but also exert a broad spectrum of functions involving modulation of mitochondrial activity and acting as anti-inflammatory and neuroregenerative agents. Besides affective symptoms, in depression cognitive impairment can be frequently observed, which may be ameliorated through targeting of extrasynaptic GABAA receptors either via TSPO ligands or exogenously administered 3α-reduced neurosteroids. Interestingly, recent findings indicate an enhanced activation of the complement system, e.g., enhanced expression of C1q, both in depression and dementia. It is of note that benzodiazepines have been shown to reduce long-term potentiation and to cause cognitive decline. Intriguingly, TSPO may be crucial in mediating the effects of benzodiazepines on synaptic pruning. Here, we discuss how benzodiazepines and TSPO may interfere with synaptic pruning. Moreover, we highlight recent developments of TSPO ligands and 3α-reduced neurosteroids as therapeutic agents. Etifoxine is the only clinically available TSPO ligand so far and has been studied in anxiety disorders. Regarding 3α-reduced neurosteroids, brexanolone, an intravenous formulation of allopregnanolone, has been approved for the treatment of postpartum depression and zuranolone, an orally available 3α-reduced neurosteroid, is currently being studied in major depressive disorder and postpartum depression. As such, 3α-reduced neurosteroids and TSPO ligands may constitute promising treatment approaches for affective disorders.
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Affiliation(s)
- Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, University Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany.
| | - Arpit Kumar Pradhan
- Experimental Neuropharmacology, Department of Anesthesiology, Technical University Munich, Munich, Germany
| | - Marco Kufner
- Department of Psychiatry and Psychotherapy, University Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany
| | - Lisa Marie Brunner
- Department of Psychiatry and Psychotherapy, University Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany
| | - Caroline Nothdurfter
- Department of Psychiatry and Psychotherapy, University Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany
| | - Simon Wein
- Department of Psychiatry and Psychotherapy, University Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany
| | - Jens Schwarzbach
- Department of Psychiatry and Psychotherapy, University Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany
| | - Xenia Puig
- Experimental Neuropharmacology, Department of Anesthesiology, Technical University Munich, Munich, Germany
| | - Christian Rupprecht
- Experimental Neuropharmacology, Department of Anesthesiology, Technical University Munich, Munich, Germany
| | - Gerhard Rammes
- Experimental Neuropharmacology, Department of Anesthesiology, Technical University Munich, Munich, Germany
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Yang X, Cai M. New Insights into the Mutual Promotion of Rosacea, Anxiety, and Depression from Neuroendocrine Immune Aspects. Clin Cosmet Investig Dermatol 2023; 16:1363-1371. [PMID: 37275216 PMCID: PMC10238710 DOI: 10.2147/ccid.s413237] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Accepted: 05/22/2023] [Indexed: 06/07/2023]
Abstract
Rosacea is a common chronic inflammatory skin disease with a complex etiology and undefined pathogenesis, and there is still a lack of targeted clinical treatment. Patients with rosacea are at a higher risk of anxiety and depression compared to the healthy population. Compared to skin conditions such as acne and psoriasis, rosacea has been much less studied in relation to multiple-etiology psychiatric disorders such as anxiety and depression. In contrast to the mainstream belief that the causal association between rosacea and psychiatric disorders is that rosacea increases the psychological burden of patients and thus triggers psychiatric disorders simply by altering their facial appearance, this review outlines the possible common mechanisms between rosacea and anxiety and depression disorders, starting from the pathophysiological mechanisms of transient receptor potential family cation channels, HPA axis, and Th1/Th17 cell polarization. It envisages the possibility of the neuroendocrine-immune interplay between rosacea and anxiety and depression, and new ideas on the complex causal relationship between rosacea and psychiatric disorders, offering more orientations to open up new therapeutic approaches for rosacea.
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Affiliation(s)
- Xiaoting Yang
- Department of Dermatology and Venereology, the Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650101, People’s Republic of China
| | - Mei Cai
- Department of Dermatology and Venereology, the Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650101, People’s Republic of China
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9
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Royse SK, Lopresti BJ, Mathis CA, Tollefson S, Narendran R. Beyond monoamines: II. Novel applications for PET imaging in psychiatric disorders. J Neurochem 2023; 164:401-443. [PMID: 35716057 DOI: 10.1111/jnc.15657] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/07/2022] [Accepted: 06/08/2022] [Indexed: 11/27/2022]
Abstract
Early applications of positron emission tomography (PET) in psychiatry sought to identify derangements of cerebral blood flow and metabolism. The need for more specific neurochemical imaging probes was soon evident, and these probes initially targeted the sites of action of neuroleptic (dopamine D2 receptors) and psychoactive (serotonin receptors) drugs. For nearly 30 years, the centrality of monoamine dysfunction in psychiatric disorders drove the development of an armamentarium of monoaminergic PET radiopharmaceuticals and imaging methodologies. However, continued investments in monoamine-enhancing drug development realized only modest gains in efficacy and tolerability. As patent protection for many widely prescribed and profitable psychiatric drugs lapsed, drug development pipelines shifted away from monoamines in search of novel targets with the promises of improved efficacy, or abandoned altogether. Over this period, PET radiopharmaceutical development activities closely parallelled drug development priorities, resulting in the development of new PET imaging agents for non-monoamine targets. In part two of this review, we survey clinical research studies using the novel targets and radiotracers described in part one across major psychiatric application areas such as substance use disorders, anxiety disorders, eating disorders, personality disorders, mood disorders, and schizophrenia. Important limitations of the studies described are discussed, as well as key methodologic issues, challenges to the field, and the status of clinical trials seeking to exploit these targets for novel therapeutics.
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Affiliation(s)
- Sarah K Royse
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Brian J Lopresti
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Chester A Mathis
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Savannah Tollefson
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Rajesh Narendran
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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10
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Liere P, Liu GJ, Pianos A, Middleton RJ, Banati RB, Akwa Y. The Comprehensive Steroidome in Complete TSPO/PBR Knockout Mice under Basal Conditions. Int J Mol Sci 2023; 24:ijms24032474. [PMID: 36768796 PMCID: PMC9916858 DOI: 10.3390/ijms24032474] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/23/2023] [Accepted: 01/25/2023] [Indexed: 01/31/2023] Open
Abstract
The 18 kDa translocator protein (TSPO/PBR) is a multifunctional evolutionary highly conserved outer mitochondrial membrane protein. Decades of research has reported an obligatory role of TSPO/PBR in both mitochondrial cholesterol transport and, thus, steroid production. However, the strict dependency of steroidogenesis on TSPO/PBR has remained controversial. The aim of this study was to provide insight into the steroid profile in complete C57BL/6-Tspotm1GuWu(GuwiyangWurra)-knockout male mice (TSPO-KO) under basal conditions. The steroidome in the brain, adrenal glands, testes and plasma was measured by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). We found that steroids present in wild-type (WT) mice were also detected in TSPO-KO mice, including pregnenolone (PREG), progestogens, mineralo-glucocorticosteroids and androgens. The concentrations of PREG and most metabolites were similar between genotypes, except a significant decrease in the levels of the 5α-reduced metabolites of progesterone (PROG) in adrenal glands and plasma and of the 5α-reduced metabolites of corticosterone (B) in plasma in TSPO-KO compared to WT animals, suggesting other regulatory functions for the TSPO/PBR. The expression levels of the voltage-dependent anion-selective channel (VDAC-1), CYP11A1 and 5α-reductase were not significantly different between both groups. Thus, the complete deletion of the tspo gene in male mice does not impair de novo steroidogenesis in vivo.
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Affiliation(s)
- Philippe Liere
- Disease and Hormones of the Nervous System, U1195 Inserm-Université Paris Saclay, 80 rue du Général Leclerc, 94276 Kremlin-Bicêtre, France
| | - Guo-Jun Liu
- Australian Nuclear Science and Technology Organisation (ANSTO), Kirrawee, NSW 2232, Australia
- Faculty of Medicine and Health, Medical Imaging Sciences, Brain and Mind Centre, University of Sydney, Camperdown, NSW 2006, Australia
| | - Antoine Pianos
- Disease and Hormones of the Nervous System, U1195 Inserm-Université Paris Saclay, 80 rue du Général Leclerc, 94276 Kremlin-Bicêtre, France
| | - Ryan J. Middleton
- Australian Nuclear Science and Technology Organisation (ANSTO), Kirrawee, NSW 2232, Australia
| | - Richard B. Banati
- Australian Nuclear Science and Technology Organisation (ANSTO), Kirrawee, NSW 2232, Australia
- Faculty of Medicine and Health, Medical Imaging Sciences, Brain and Mind Centre, University of Sydney, Camperdown, NSW 2006, Australia
| | - Yvette Akwa
- Disease and Hormones of the Nervous System, U1195 Inserm-Université Paris Saclay, 80 rue du Général Leclerc, 94276 Kremlin-Bicêtre, France
- Correspondence: ; Tel.: +33-(0)1-49591878
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11
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Xiong B, Zhong Z, Chen C, Huang H, Lin J, Xu Y, Yang J, Yu C. The anxiolytic effect of koumine on a predatory sound stress-induced anxiety model and its associated molecular mechanisms. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2022; 103:154225. [PMID: 35689899 DOI: 10.1016/j.phymed.2022.154225] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 05/24/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Koumine is the most abundant alkaloid extracted from Gelsemium elegans Benth.. Preliminary studies by our research group have shown that koumine has significant anxiolytic effect, but this needs to be further confirmed. HYPOTHESIS/PURPOSE To investigate the potential anxiolytic effect of koumine on predatory sound (PS) stress-induced anxiety models and preliminarily explore its therapeutic targets and molecular mechanisms. STUDY DESIGN AND METHODS The anxiolytic effect of koumine in an animal model of acute PS stress-induced anxiety were determined. Then, neurosteroids levels in the main brain regions involved in anxiety disorders, as well as plasma adrenocorticotropic hormone (ACTH) and corticosterone (CORT) levels, were determinated. Finally, to clarify the effect of koumine on translocator protein 18 kDa (TSPO), the affinity between koumine and TSPO was evaluated by surface plasmon resonance (SPR) technology. RESULTS Koumine treatment mitigated anxiety-like behavior following acute PS stress in the open field test and elevated plus maze test. PS exposure significantly decreased progesterone and allopregnanolone levels in the PFC, Hip, and Amy and increased ACTH and CORT levels in plasma, and koumine administration significantly reversed these effects. Finally, the reliable SPR results showed that the KD of koumine with TSPO was 155.33 ± 11.0 μM, indicating that koumine is a human TSPO high-affinity ligand that has an affinity comparable to typical TSPO ligands. CONCLUSION Our results show that koumine has obvious anxiolytic effect in the PS-induced anxiety model. Targeting TSPO-neurosteroids-HPA axis may be an important mechanism by which koumine exerts its anxiolytic effect.
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Affiliation(s)
- Bojun Xiong
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
| | - Zhifeng Zhong
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China; Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing 400038, China
| | - Chaojie Chen
- School of Chemical Engineering and Resource Recycling, Wuzhou University, Wuzhou 543002, China; Fujian Center for Safety Evaluation of New Drug, Fujian Medical University, Fuzhou 350122, China
| | - Huihui Huang
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China; Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
| | - Jinxiang Lin
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
| | - Ying Xu
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China; Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China.
| | - Jian Yang
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China; Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China.
| | - Changxi Yu
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China; Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China.
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12
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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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13
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Rupprecht R, Wetzel CH, Dorostkar M, Herms J, Albert NL, Schwarzbach J, Schumacher M, Neumann ID. Translocator protein (18kDa) TSPO: a new diagnostic or therapeutic target for stress-related disorders? Mol Psychiatry 2022; 27:2918-2926. [PMID: 35444254 DOI: 10.1038/s41380-022-01561-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 03/25/2022] [Accepted: 03/31/2022] [Indexed: 12/11/2022]
Abstract
Efficient treatment of stress-related disorders, such as depression, is still a major challenge. The onset of antidepressant drug action is generally quite slow, while the anxiolytic action of benzodiazepines is considerably faster. However, their long-term use is impaired by tolerance development, abuse liability and cognitive impairment. Benzodiazepines act as positive allosteric modulators of ɣ-aminobutyric acid type A (GABAA) receptors. 3α-reduced neurosteroids such as allopregnanolone also are positive allosteric GABAA receptor modulators, however, through a site different from that targeted by benzodiazepines. Recently, the administration of neurosteroids such as brexanolone or zuranolone has been shown to rapidly ameliorate symptoms in post-partum depression or major depressive disorder. An attractive alternative to the administration of exogenous neurosteroids is promoting endogenous neurosteroidogenesis via the translocator protein 18k Da (TSPO). TSPO is a transmembrane protein located primarily in mitochondria, which mediates numerous biological functions, e.g., steroidogenesis and mitochondrial bioenergetics. TSPO ligands have been used in positron emission tomography (PET) studies as putative markers of microglia activation and neuroinflammation in stress-related disorders. Moreover, TSPO ligands have been shown to modulate neuroplasticity and to elicit antidepressant and anxiolytic therapeutic effects in animals and humans. As such, TSPO may open new avenues for understanding the pathophysiology of stress-related disorders and for the development of novel treatment options.
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Affiliation(s)
- Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053, Regensburg, Germany.
| | - Christian H Wetzel
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053, Regensburg, Germany
| | - Mario Dorostkar
- Center for Neuropathology and Prion Research, Ludwig-Maximilian-University Munich, 81377, Munich, Germany
| | - Jochen Herms
- Center for Neuropathology and Prion Research, Ludwig-Maximilian-University Munich, 81377, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), 81377, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), 81377, Munich, Germany
| | - Nathalie L Albert
- Department of Nuclear Medicine, Ludwig-Maximilian-University Munich, 81377, Munich, Germany
| | - Jens Schwarzbach
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053, Regensburg, Germany
| | - Michael Schumacher
- Research Unit 1195, INSERM and University Paris-Saclay, 94276, Le Kremlin-Bicêtre, France
| | - Inga D Neumann
- Department of Neurobiology and Animal Physiology, University Regensburg, 93040, Regensburg, Germany
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14
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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)
| | | | | | | | - 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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15
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Rupprecht R, Rupprecht C, Di Benedetto B, Rammes G. Neuroinflammation and psychiatric disorders: Relevance of C1q, translocator protein (18 kDa) (TSPO), and neurosteroids. World J Biol Psychiatry 2022; 23:257-263. [PMID: 34320915 DOI: 10.1080/15622975.2021.1961503] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
There is increasing evidence that neuroinflammatory processes may play a role in the pathophysiology of psychiatric disorders. Recently, the complement protein C1q and the translocator protein (18 kDa) (TSPO) have attracted considerable interest in this context. C1q is a small molecule which is involved into synaptic pruning mechanisms, increases during ageing and may contribute to neurodegenerative disorders. TSPO is a transmembrane channel protein and mediates numerous biological functions such as bioenergetics and steroid synthesis. Meanwhile, there is evidence that both C1q and TSPO may be elevated in psychiatric disorders, e.g. major depression. Moreover, preclinical and first clinical studies suggest that TSPO ligands may exert antidepressant and anxiolytic properties by promoting endogenous neurosteroid synthesis. In addition, certain neurosteroids, e.g. allopregnanolone, are potent positive allosteric modulators of GABAA receptors and their composition is altered in depression and anxiety disorders. Recently, neurosteroid compounds such as brexanolone or zuranolone have been reported to reduce depressive and anxiety symptoms in postpartum depression and major depressive disorder. In conclusion, compounds enhancing GABAergic neurotransmission such as neurosteroids and TSPO ligands, which also may exert anti-inflammatory properties in concert with immunomodulators such as C1q may open new avenues for the treatment of psychiatric disorders.
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Affiliation(s)
- Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, University Regensburg, Regensburg, Germany
| | - Christian Rupprecht
- Experimental Neuropharmacology, Department of Anesthesiology, Technische Universität München, Munich, Germany
| | - Barbara Di Benedetto
- Department of Psychiatry and Psychotherapy, University Regensburg, Regensburg, Germany
| | - Gerhard Rammes
- Experimental Neuropharmacology, Department of Anesthesiology, Technische Universität München, Munich, Germany
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16
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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: 81] [Impact Index Per Article: 27.0] [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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17
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Midazolam Exposure Impedes Oligodendrocyte Development via the Translocator Protein and Impairs Myelination in Larval Zebrafish. Mol Neurobiol 2021; 59:93-106. [PMID: 34626343 DOI: 10.1007/s12035-021-02559-8] [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: 07/16/2021] [Accepted: 09/09/2021] [Indexed: 10/20/2022]
Abstract
Anesthetics are commonly used in various medical procedures. Accumulating evidence suggests that early-life anesthetics exposure in infants and children affects brain development, causing psychiatric and neurological disorders. However, the underlying mechanisms are poorly understood. Using zebrafish larvae as a model, we found that the proliferation and migration of oligodendrocyte progenitor cells (OPCs) were severely impaired by the exposure of midazolam (MDZ), an anesthetic widely used in pediatric surgery and intensive care medicine, leading to a reduction of oligodendroglial lineage cell in the dorsal spinal cord. This defect was mimicked by the bath application of translocator protein (TSPO) agonists and partially rescued by genetic downregulation of TSPO. Cell transplantation experiments showed that requirement of TSPO for MDZ-induced oligodendroglial lineage cell defects is cell-autonomous. Furthermore, transmission electron microscopy and in vivo electrophysiological recording experiments demonstrated that MDZ exposure caused axon hypomyelination and action potential propagation retardation, resulting in delayed behavior initiation. Thus, our findings reveal that MDZ affects oligodendroglial lineage cell development and myelination in young animals, raising the care about its clinic use in infants and children.
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18
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Giordani A, Menziani MC, Moresco RM, Matarrese M, Paolino M, Saletti M, Giuliani G, Anzini M, Cappelli A. Exploring Translocator Protein (TSPO) Medicinal Chemistry: An Approach for Targeting Radionuclides and Boron Atoms to Mitochondria. J Med Chem 2021; 64:9649-9676. [PMID: 34254805 DOI: 10.1021/acs.jmedchem.1c00379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Translocator protein 18 kDa [TSPO or peripheral-type benzodiazepine receptor (PBR)] was identified in the search of binding sites for benzodiazepine anxiolytic drugs in peripheral regions. In these areas, binding sites for TSPO ligands were recognized in steroid-producing tissues. TSPO plays an important role in many cellular functions, and its coding sequence is highly conserved across species. TSPO is located predominantly on the membrane of mitochondria and is overexpressed in several solid cancers. TSPO basal expression in the CNS is low, but it becomes high in neurodegenerative conditions. Thus, TSPO constitutes not only as an outstanding drug target but also as a valuable marker for the diagnosis of a number of diseases. The aim of the present article is to show the lesson we have learned from our activity in TSPO medicinal chemistry and in approaching the targeted delivery to mitochondria by means of TSPO ligands.
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Affiliation(s)
- Antonio Giordani
- Rottapharm Biotech S.p.A., Via Valosa di Sopra 9, 20900 Monza, Italy
| | - Maria Cristina Menziani
- Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, Via Campi 103, 41121 Modena, Italy
| | - Rosa Maria Moresco
- Department of Medicine and Surgery, University of Milan-Bicocca, Nuclear Medicine Department, San Raffaele Scientific Institute, IBFM-CNR, Via Olgettina 60, 20132 Milano, Italy
| | - Mario Matarrese
- Department of Medicine and Surgery, University of Milan-Bicocca, Nuclear Medicine Department, San Raffaele Scientific Institute, IBFM-CNR, Via Olgettina 60, 20132 Milano, Italy
| | - Marco Paolino
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Mario Saletti
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Germano Giuliani
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Maurizio Anzini
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Andrea Cappelli
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
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19
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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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