1
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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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Guillemain G, Khemtemourian L, Brehat J, Morin D, Movassat J, Tourrel-Cuzin C, Lacapere JJ. TSPO in pancreatic beta cells and its possible involvement in type 2 diabetes. Biochimie 2024; 224:104-113. [PMID: 38908539 DOI: 10.1016/j.biochi.2024.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 06/19/2024] [Accepted: 06/20/2024] [Indexed: 06/24/2024]
Abstract
Amyloidosis forms a large family of pathologies associated with amyloid deposit generated by the formation of amyloid fibrils or plaques. The amyloidogenic proteins and peptides involved in these processes are targeted against almost all organs. In brain they are associated with neurodegenerative disease, and the Translocator Protein (TSPO), overexpressed in these inflammatory conditions, is one of the target for the diagnostic. Moreover, TSPO ligands have been described as promising therapeutic drugs for neurodegenerative diseases. Type 2 diabetes, another amyloidosis, is due to a beta cell mass decrease that has been linked to hIAPP (human islet amyloid polypeptide) fibril formation, leading to the reduction of insulin production. In the present study, in a first approach, we link overexpression of TSPO and inflammation in potentially prediabetic patients. In a second approach, we observed that TSPO deficient rats have higher level of insulin secretion in basal conditions and more IAPP fibrils formation compared with wild type animals. In a third approach, we show that diabetogenic conditions also increase TSPO overexpression and IAPP fibril formation in rat beta pancreatic cell line (INS-1E). These data open the way for further studies in the field of type 2 diabetes treatment or prevention.
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Affiliation(s)
- Ghislaine Guillemain
- Sorbonne Université, Institut Hospitalo-Universitaire, INSERM UMR_S938, Institute of Cardiometabolism and Nutrition (ICAN), Centre de Recherche de St-Antoine (CRSA), 27 Rue de Chaligny, 75012, Paris, France.
| | | | - Juliette Brehat
- INSERM, U955, IMRB, équipe Ghaleh, Faculté de Médecine, UPEC, 94010, Créteil, France
| | - Didier Morin
- INSERM, U955, IMRB, équipe Ghaleh, Faculté de Médecine, UPEC, 94010, Créteil, France
| | - Jamileh Movassat
- Université Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, CNRS UMR 8251, Team "Biologie et Pathologie du Pancréas Endocrine", Paris, France
| | - Cécile Tourrel-Cuzin
- Université Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, CNRS UMR 8251, Team "Biologie et Pathologie du Pancréas Endocrine", Paris, France
| | - Jean-Jacques Lacapere
- Sorbonne Université, Ecole normale supérieure, PSL University, CNRS, Laboratoire des Biomolécules, LBM, 75005, Paris, France.
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3
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Twitto-Greenberg R, Liraz-Zaltsman S, Michaelson DM, Liraz O, Lubitz I, Atrakchi-Baranes D, Shemesh C, Ashery U, Cooper I, Harari A, Harats D, Schnaider-Beeri M, Shaish A. 9-cis beta-carotene-enriched diet significantly improved cognition and decreased Alzheimer's disease neuropathology and neuroinflammation in Alzheimer's disease-like mouse models. Neurobiol Aging 2024; 133:16-27. [PMID: 38381472 DOI: 10.1016/j.neurobiolaging.2023.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 09/10/2023] [Accepted: 09/17/2023] [Indexed: 02/22/2024]
Abstract
A significant progressive decline in beta-carotene (βC) levels in the brain is associated with cognitive impairment and a higher prevalence of Alzheimer's disease (AD). In this study, we investigated whether the administration of 9-cis beta-carotene (9CBC)-rich powder of the alga Dunaliella bardawil, the best-known source of βC in nature, inhibits the development of AD-like neuropathology and cognitive deficits. We demonstrated that in 3 AD mouse models, Tg2576, 5xFAD, and apoE4, 9CBC treatment improved long- and short-term memory, decreased neuroinflammation, and reduced the prevalence of β-amyloid plaques and tau hyperphosphorylation. These findings suggest that 9CBC has the potential to be an effective preventive and symptomatic AD therapy.
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Affiliation(s)
- Rachel Twitto-Greenberg
- The Bert W. Strassburger Metabolic Center, Sheba Medical Center, Ramat-Gan, Israel; The Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel; The Joseph Sagol Neuroscience Center, Sheba Medical Center, Ramat-Gan, Israel
| | - Sigal Liraz-Zaltsman
- The Joseph Sagol Neuroscience Center, Sheba Medical Center, Ramat-Gan, Israel; Department of Pharmacology, Institute for Drug Research, Hebrew University, Jerusalem, Israel; Institutes for Health and Medical Professions, Department of Sports Therapy, Ono Academic College, Kyrat-Ono, Israel
| | - Daniel M Michaelson
- The Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Ori Liraz
- The Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Irit Lubitz
- The Joseph Sagol Neuroscience Center, Sheba Medical Center, Ramat-Gan, Israel
| | | | - Chen Shemesh
- The Joseph Sagol Neuroscience Center, Sheba Medical Center, Ramat-Gan, Israel
| | - Uri Ashery
- The Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Itzik Cooper
- The Joseph Sagol Neuroscience Center, Sheba Medical Center, Ramat-Gan, Israel; Institutes for Health and Medical Professions, Department of Sports Therapy, Ono Academic College, Kyrat-Ono, Israel
| | - Ayelet Harari
- The Bert W. Strassburger Metabolic Center, Sheba Medical Center, Ramat-Gan, Israel
| | - Dror Harats
- The Bert W. Strassburger Metabolic Center, Sheba Medical Center, Ramat-Gan, Israel; The Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | | | - Aviv Shaish
- The Bert W. Strassburger Metabolic Center, Sheba Medical Center, Ramat-Gan, Israel; Department of Life Sciences, Achva Academic College, Be'er-Tuvia Regional Council, Israel.
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4
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Zhang S, Deng Z, Qiu Y, Lu G, Wu J, Huang H. FGIN-1-27 Mitigates Radiation-induced Mitochondrial Hyperfunction and Cellular Hyperactivation in Cultured Astrocytes. Neuroscience 2023; 535:23-35. [PMID: 37913861 DOI: 10.1016/j.neuroscience.2023.10.017] [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: 08/14/2023] [Revised: 10/04/2023] [Accepted: 10/21/2023] [Indexed: 11/03/2023]
Abstract
Radiation-induced brain injury (RBI) poses a significant challenge in the context of radiotherapy for intracranial tumors, necessitating a comprehensive understanding of the cellular and molecular mechanisms involved. While prior investigations have underscored the role of astrocyte activation and excessive vascular endothelial growth factor production in microvascular damage associated with RBI, there remains a scarcity of studies examining the impact of radiation on astrocytes, particularly regarding organelles such as mitochondria. Thus, our study aimed to elucidate alterations in astrocyte and mitochondrial functionality following radiation exposure, with a specific focus on evaluating the potential ameliorative effects of translocator protein 18 kDa(TSPO) ligands. In this study, cultured astrocytes were subjected to X-ray irradiation, and their cellular states and mitochondrial functions were examined and compared to control cells. Our findings revealed that radiation-induced astrocytic hyperactivation, transforming them into the neurotoxic A1-type, concomitant with reduced cell proliferation. Additionally, radiation triggered mitochondrial hyperfunction, heightened the mitochondrial membrane potential, and increased oxidative metabolite production. However, following treatment with FGIN-1-27, a TSPO ligand, we observed a restoration of mitochondrial function and a reduction in oxidative metabolite production. Moreover, this intervention mitigated astrocyte hyperactivity, decreased the number of A1-type astrocytes, and restored cell proliferative capacity. In conclusion, our study has unveiled additional manifestations of radiation-induced astrocyte dysfunction and validated that TSPO ligands may serve as a promising therapeutic strategy to mitigate this dysfunction. It has potential clinical implications for the treatment of RBI.
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Affiliation(s)
- Shifeng Zhang
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, No. 58 Zhongshan Road 2, Guangzhou 510080, China
| | - Zhezhi Deng
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, No. 58 Zhongshan Road 2, Guangzhou 510080, China
| | - Yuemin Qiu
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, No. 58 Zhongshan Road 2, Guangzhou 510080, China
| | - Gengxin Lu
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, No. 58 Zhongshan Road 2, Guangzhou 510080, China
| | - Junyu Wu
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, No. 58 Zhongshan Road 2, Guangzhou 510080, China
| | - Haiwei Huang
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, No. 58 Zhongshan Road 2, Guangzhou 510080, China.
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5
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Mahemuti Y, Kadeer K, Su R, Abula A, Aili Y, Maimaiti A, Abulaiti S, Maimaitituerxun M, Miao T, Jiang S, Axier A, Aisha M, Wang Y, Cheng X. TSPO exacerbates acute cerebral ischemia/reperfusion injury by inducing autophagy dysfunction. Exp Neurol 2023; 369:114542. [PMID: 37717810 DOI: 10.1016/j.expneurol.2023.114542] [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: 12/31/2022] [Revised: 09/12/2023] [Accepted: 09/13/2023] [Indexed: 09/19/2023]
Abstract
Autophagy is considered a double-edged sword, with a role in the regulation of the pathophysiological processes of the central nervous system (CNS) after cerebral ischemia-reperfusion injury (CIRI). The 18-kDa translocator protein (TSPO) is a highly conserved protein, with its expression level in the nervous system closely associated with the regulation of pathophysiological processes. In addition, the ligand of TSPO reduces neuroinflammation in brain diseases, but the potential role of TSPO in CIRI is largely undiscovered. On this basis, we investigated whether TSPO regulates neuroinflammatory response by affecting autophagy in microglia. In our study, increased expression of TSPO was detected in rat brain tissues with transient middle cerebral artery occlusion (tMCAO) and in BV2 microglial cells exposed to oxygen-glucose deprivation or reoxygenation (OGD/R) treatment, respectively. In addition, we confirmed that autophagy was over-activated during CIRI by increased expression of autophagy activation related proteins with Beclin-1 and LC3B, while the expression of p62 was decreased. The degradation process of autophagy was inhibited, while the expression levels of LAMP-1 and Cathepsin-D were significantly reduced. Results of confocal laser microscopy and transmission electron microscopy (TEM) indicated that autophagy flux was disordered. In contrast, inhibition of TSPO prevented autophagy over-activation both in vivo and in vitro. Interestingly, suppression of TSPO alleviated nerve cell damage by reducing reactive oxygen species (ROS) and pro-inflammatory factors, including TNF-α and IL-6 in microglia cells. In summary, these results indicated that TSPO might affect CIRI by mediating autophagy dysfunction and thus might serve as a potential target for ischemic stroke treatment.
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Affiliation(s)
- Yusufu Mahemuti
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China; School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou 310058, Zhejiang, PR China; Liangzhu Laboratory, MOE Frontier Science Center for Brain Science & Brain-Machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, Zhejiang, PR China; NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, Zhejiang, PR China
| | - Kaheerman Kadeer
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Riqing Su
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Abudureheman Abula
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Yirizhati Aili
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Aierpati Maimaiti
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Subinuer Abulaiti
- Department of Epidemiology and Biostatistics, Institute of Public Health, Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | | | - Tong Miao
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Shihao Jiang
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Aximujiang Axier
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Maimaitili Aisha
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Yongxin Wang
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Xiaojiang Cheng
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China.
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6
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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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Fronza MG, Alves D, Praticò D, Savegnago L. The neurobiology and therapeutic potential of multi-targeting β-secretase, glycogen synthase kinase 3β and acetylcholinesterase in Alzheimer's disease. Ageing Res Rev 2023; 90:102033. [PMID: 37595640 DOI: 10.1016/j.arr.2023.102033] [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: 06/16/2023] [Revised: 08/04/2023] [Accepted: 08/14/2023] [Indexed: 08/20/2023]
Abstract
Alzheimer's Disease (AD) is the most common form of dementia, affecting almost 50 million of people around the world, characterized by a complex and age-related progressive pathology with projections to duplicate its incidence by the end of 2050. AD pathology has two major hallmarks, the amyloid beta (Aβ) peptides accumulation and tau hyperphosphorylation, alongside with several sub pathologies including neuroinflammation, oxidative stress, loss of neurogenesis and synaptic dysfunction. In recent years, extensive research pointed out several therapeutic targets which have shown promising effects on modifying the course of the disease in preclinical models of AD but with substantial failure when transposed to clinic trials, suggesting that modulating just an isolated feature of the pathology might not be sufficient to improve brain function and enhance cognition. In line with this, there is a growing consensus that an ideal disease modifying drug should address more than one feature of the pathology. Considering these evidence, β-secretase (BACE1), Glycogen synthase kinase 3β (GSK-3β) and acetylcholinesterase (AChE) has emerged as interesting therapeutic targets. BACE1 is the rate-limiting step in the Aβ production, GSK-3β is considered the main kinase responsible for Tau hyperphosphorylation, and AChE play an important role in modulating memory formation and learning. However, the effects underlying the modulation of these enzymes are not limited by its primarily functions, showing interesting effects in a wide range of impaired events secondary to AD pathology. In this sense, this review will summarize the involvement of BACE1, GSK-3β and AChE on synaptic function, neuroplasticity, neuroinflammation and oxidative stress. Additionally, we will present and discuss new perspectives on the modulation of these pathways on AD pathology and future directions on the development of drugs that concomitantly target these enzymes.
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Affiliation(s)
- Mariana G Fronza
- Neurobiotechnology Research Group (GPN) - Centre for Technology Development CDTec, Federal University of Pelotas (UFPel), Pelotas, RS, Brazil
| | - Diego Alves
- Laboratory of Clean Organic Synthesis (LASOL), Center for Chemical, Pharmaceutical and Food Sciences (CCQFA), UFPel, RS, Brazil
| | - Domenico Praticò
- Alzheimer's Center at Temple - ACT, Temple University, Lewis Katz School of Medicine, Philadelphia, PA, United States
| | - Lucielli Savegnago
- Neurobiotechnology Research Group (GPN) - Centre for Technology Development CDTec, Federal University of Pelotas (UFPel), Pelotas, RS, Brazil.
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8
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Tournier B, Bouteldja F, Amossé Q, Nicolaides A, Duarte Azevedo M, Tenenbaum L, Garibotto V, Ceyzériat K, Millet P. 18 kDa Translocator Protein TSPO Is a Mediator of Astrocyte Reactivity. ACS OMEGA 2023; 8:31225-31236. [PMID: 37663488 PMCID: PMC10468775 DOI: 10.1021/acsomega.3c03368] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/01/2023] [Indexed: 09/05/2023]
Abstract
An increase in astrocyte reactivity has been described in Alzheimer's disease and seems to be related to the presence of a pro-inflammatory environment. Reactive astrocytes show an increase in the density of the 18 kDa translocator protein (TSPO), but TSPO involvement in astrocyte functions remains poorly understood. The goal of this study was to better characterize the mechanisms leading to the increase in TSPO under inflammatory conditions and the associated consequences. For this purpose, the C6 astrocytic cell line was used in the presence of lipopolysaccharide (LPS) or TSPO overexpression mediated by the transfection of a plasmid encoding TSPO. The results show that nonlethal doses of LPS induced TSPO expression at mRNA and protein levels through a STAT3-dependent mechanism and increased the number of mitochondria per cell. LPS stimulated reactive oxygen species (ROS) production and decreased glucose consumption (quantified by the [18F]FDG uptake), and these effects were diminished by FEPPA, a TSPO antagonist. The transfection-mediated overexpression of TSPO induced ROS production, and this effect was blocked by FEPPA. In addition, a synergistic effect of overexpression of TSPO and LPS on ROS production was observed. These data show that the increase of TSPO in astrocytic cells is involved in the regulation of glucose metabolism and in the pro-inflammatory response. These data suggest that the overexpression of TSPO by astrocytes in Alzheimer's disease would have rather deleterious effects by promoting the pro-inflammatory response.
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Affiliation(s)
- Benjamin
B. Tournier
- Department
of Psychiatry, University Hospitals of Geneva, Geneva 1206, Switzerland
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
| | - Farha Bouteldja
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
| | - Quentin Amossé
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
| | - Alekos Nicolaides
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
| | - Marcelo Duarte Azevedo
- Laboratory
of Cellular and Molecular Neurotherapies, Center for Neuroscience
Research, Clinical Neuroscience Department, Lausanne University Hospital, Lausanne 1011, Switzerland
| | - Liliane Tenenbaum
- Laboratory
of Cellular and Molecular Neurotherapies, Center for Neuroscience
Research, Clinical Neuroscience Department, Lausanne University Hospital, Lausanne 1011, Switzerland
| | - Valentina Garibotto
- Division
of Nuclear Medicine, Diagnostic Department, University Hospitals of Geneva, Geneva 1206, Switzerland
- CIBM
Center for BioMedical Imaging; NIMTLab, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland
| | - Kelly Ceyzériat
- Department
of Psychiatry, University Hospitals of Geneva, Geneva 1206, Switzerland
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
- Division
of Nuclear Medicine, Diagnostic Department, University Hospitals of Geneva, Geneva 1206, Switzerland
- CIBM
Center for BioMedical Imaging; NIMTLab, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland
| | - Philippe Millet
- Department
of Psychiatry, University Hospitals of Geneva, Geneva 1206, Switzerland
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
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9
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Nisha Aji K, Hafizi S, Da Silva T, Kiang M, Rusjan PM, Weickert CS, Mizrahi R. Interaction between peripheral and central immune markers in clinical high risk for psychosis. Brain Behav Immun Health 2023; 30:100636. [PMID: 37293440 PMCID: PMC10244662 DOI: 10.1016/j.bbih.2023.100636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 05/07/2023] [Indexed: 06/10/2023] Open
Abstract
Neuroinflammatory events prior to the diagnosis of schizophrenia may play a role in transition to illness. To date only one in-vivo study has investigated this association between peripheral proinflammatory cytokines and brain markers of inflammation (e.g., mitochondrial 18 kDa translocator protein, TSPO) in schizophrenia, but none in its putative prodrome. In this study, we primarily aimed to (Barron et al., 2017) test study group (clinical high-risk (CHR) and healthy controls) differences in peripheral inflammatory markers and test for any associations with symptom measures, (Hafizi et al., 2017a) investigate the interaction between brain TSPO levels (dorsolateral prefrontal cortex (DLPFC) and hippocampus) and peripheral inflammatory clusters (entire cohort and (CHR) group independently) within a relatively large group of individuals at CHR for psychosis (N = 38) and healthy controls (N = 20). Participants underwent structural brain magnetic resonance imaging (MRI) and TSPO [18F]FEPPA positron emission tomography (PET) scans. Serum samples were assessed for peripheral inflammatory markers (i.e., CRP and interleukins). For exploratory analysis, we aimed to examine cluster differences for symptom measures and identify independent peripheral predictors of brain TSPO expression. Here, we report increased IL-8 levels that are positively correlated with prodromal general symptom severity and showed trend-level association with apathy in CHR. We identified distinct inflammatory clusters characterized by inflammatory markers (IL-1 β, IL-2, IFN-γ) that were comparable between entire cohort and CHR. TSPO levels did not differ between inflammatory clusters (entire cohort or CHR). Finally, we show that CRP, IL-1 β, TNF-α, and IFN-γ levels were the independent peripheral predictors of brain TSPO expression. Thus, alterations in brain TSPO expression in response to inflammatory processes are not evident in CHR. Taken together, clustering by inflammatory status is a promising strategy to characterize the interaction between brain TSPO and peripheral markers of inflammation.
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Affiliation(s)
- Kankana Nisha Aji
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Douglas Research Centre, Clinical and Translational Sciences Lab, Montreal, Quebec, Canada
| | - Sina Hafizi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Tania Da Silva
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Michael Kiang
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Pablo M. Rusjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Douglas Research Centre, Clinical and Translational Sciences Lab, Montreal, Quebec, Canada
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | | | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Douglas Research Centre, Clinical and Translational Sciences Lab, Montreal, Quebec, Canada
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
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10
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Cheung G, Lin YC, Papadopoulos V. Translocator protein in the rise and fall of central nervous system neurons. Front Cell Neurosci 2023; 17:1210205. [PMID: 37416505 PMCID: PMC10322222 DOI: 10.3389/fncel.2023.1210205] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 06/07/2023] [Indexed: 07/08/2023] Open
Abstract
Translocator protein (TSPO), a 18 kDa protein found in the outer mitochondrial membrane, has historically been associated with the transport of cholesterol in highly steroidogenic tissues though it is found in all cells throughout the mammalian body. TSPO has also been associated with molecular transport, oxidative stress, apoptosis, and energy metabolism. TSPO levels are typically low in the central nervous system (CNS), but a significant upregulation is observed in activated microglia during neuroinflammation. However, there are also a few specific regions that have been reported to have higher TSPO levels than the rest of the brain under normal conditions. These include the dentate gyrus of the hippocampus, the olfactory bulb, the subventricular zone, the choroid plexus, and the cerebellum. These areas are also all associated with adult neurogenesis, yet there is no explanation of TSPO's function in these cells. Current studies have investigated the role of TSPO in microglia during neuron degeneration, but TSPO's role in the rest of the neuron lifecycle remains to be elucidated. This review aims to discuss the known functions of TSPO and its potential role in the lifecycle of neurons within the CNS.
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11
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Angeloni E, Germelli L, Marchetti L, Da Pozzo E, Tremolanti C, Wetzel CH, Baglini E, Taliani S, Da Settimo F, Martini C, Costa B. The human microglial surveillant phenotype is preserved by de novo neurosteroidogenesis through the control of cholesterol homeostasis: Crucial role of 18 kDa Translocator Protein. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166751. [PMID: 37169037 DOI: 10.1016/j.bbadis.2023.166751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/04/2023] [Accepted: 05/05/2023] [Indexed: 05/13/2023]
Abstract
Neurodegenerative disease-associated microglia commonly exhibit harmful cholesterol accumulation that impairs their ability to resolve the neuroinflammatory response, contributing to disease onset and progression. Neurosteroids, whose levels have been often found significantly altered in brain diseases, are the most potent endogenous anti-inflammatory molecules exerting beneficial effects on activities of brain cells, including microglia. For the first time, the impact of neurosteroidogenesis on cholesterol homeostasis for the immune surveillance phenotype maintenance was investigated in a human microglia in vitro model. To enhance and inhibit neurosteroidogenesis, pharmacological stimulation and knock-down of 18 kDa Translocator Protein (TSPO), which is involved in the neurosteroidogenesis rate-limiting step, were used as experimental approaches, respectively. The obtained results point to an essential autocrine control of neurosteroidogenesis in orchestrating cholesterol trafficking in human microglia. TSPO pharmacological stimulation ensured cholesterol turnover by strengthening cholesterol efflux systems and preserving healthy immune surveillant phenotype. Conversely, TSPO knock-down induced an impairment of the controlled interplay among cholesterol synthesis, efflux, and metabolism mechanisms, leading to an excessive cholesterol accumulation and acquisition of a chronically activated dysfunctional phenotype. In this model, the exogenous neurosteroid administration restored proper the cholesterol clearance. The TSPO ability in promoting native neurosteroidogenesis opens the way to restore cholesterol homeostasis, and thus to maintain microglia proper functionality for the treatment of neuroinflammation-related brain diseases.
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Affiliation(s)
- Elisa Angeloni
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | - Lorenzo Germelli
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | - Laura Marchetti
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy; Center for Instrument Sharing University of Pisa (CISUP), Lungarno Pacinotti, 43/44, 56126 Pisa, Italy.
| | - Eleonora Da Pozzo
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy; Center for Instrument Sharing University of Pisa (CISUP), Lungarno Pacinotti, 43/44, 56126 Pisa, Italy.
| | - Chiara Tremolanti
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | - Christian H Wetzel
- Department of Psychiatry and Psychotherapy, Molecular Neurosciences, University of Regensburg, 93059 Regensburg, Germany.
| | - Emma Baglini
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | - Sabrina Taliani
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | - Federico Da Settimo
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | - Claudia Martini
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy.
| | - Barbara Costa
- Department of Pharmacy, University of Pisa, via Bonanno 6, 56126 Pisa, Italy; Center for Instrument Sharing University of Pisa (CISUP), Lungarno Pacinotti, 43/44, 56126 Pisa, Italy.
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12
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Kikutani K, Hosokawa K, Giga H, Ota K, Matsumata M, Zhu M, Takemoto H, Ji B, Ohshimo S, Shime N, Aizawa H. GENETIC DELETION OF TRANSLOCATOR PROTEIN EXACERBATES POST-SEPSIS SYNDROME WITH ACTIVATION OF THE C1Q PATHWAY IN SEPTIC MOUSE MODEL. Shock 2023; 59:82-90. [PMID: 36703279 DOI: 10.1097/shk.0000000000002030] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
ABSTRACT Significant numbers of patients who survive sepsis exhibit psychiatric and cognitive impairments, termed post-sepsis syndrome. Understanding the underlying pathophysiology is essential to develop effective therapies. Translocator protein 18 kDa (TSPO) is a multifaceted mitochondrial protein implicated in inflammation, oxidative stress, and steroidogenesis in the central nervous system. Despite accumulated evidence demonstrating TSPO is a biomarker in psychiatric and neurodegenerative disorders, the role of this protein in post-sepsis syndrome remains elusive. The aim of this study was to investigate the role of TSPO in the long-term impairment of mouse behavior associated with psychiatric and cognitive impairments following sepsis induced by cecal ligation and puncture (CLP) surgery. Animals were divided into three groups: (i) wild type (WT) + sham, (ii) WT + CLP, and (iii) TSPO knock out + CLP. Survival rate and body weight change were assessed up to 17 days after surgeries. Then, we also assessed anxiety-like behavior, depression-like behavior, cognitive function, locomotor activity, and forelimb muscle strength in surviving mice by elevated plus maze, tail suspension test, y-maze, open field test, and grip strength test, respectively. Deletion of the TSPO gene led to high mortality and prolonged weight loss and exacerbated anxiety-like and depressive-like behavior with cognitive impairment 17 days after, but not before, CLP surgery. RNA-seq analysis of the hippocampus revealed the upregulation of genes (C1qb, C1qc, and Tyrobp) in C1q complement pathways correlated significantly with anxiety-like behavior that appeared long after CLP surgery. The expressions of these genes predicted other behavioral traits, including depressive-like behavior in the tail suspension test and grip power impairment, supporting the role of the C1q pathway in post-sepsis syndrome. Because the C1q pathway has recently attracted interest as a tag for pathological synaptic elimination, the current study suggests the C1q pathway is involved in the psychiatric and cognitive impairments observed in post-sepsis syndrome.
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Affiliation(s)
| | - Koji Hosokawa
- Department of Anesthesiology and Reanimatology, Faculty of Medicine Sciences, University of Fukui, Japan
| | | | - Kohei Ota
- Department of Emergency and Critical Care Medicine, Graduate School of Biomedical and Health Science, Hiroshima University, Japan
| | - Miho Matsumata
- Department of Neurobiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Japan
| | - Meina Zhu
- Department of Neurobiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Japan
| | | | | | - Shinichiro Ohshimo
- 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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13
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Owen DR, Phillips A, O’Connor D, Grey G, Aimola L, Nicholas R, Matthews PM. Human pharmacokinetics of XBD173 and etifoxine distinguish their potential for pharmacodynamic effects mediated by translocator protein. Br J Clin Pharmacol 2022; 88:4230-4236. [PMID: 35524344 PMCID: PMC9545781 DOI: 10.1111/bcp.15392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/26/2022] [Accepted: 04/29/2022] [Indexed: 11/29/2022] Open
Abstract
XBD173 and etifoxine are translocator protein (TSPO) ligands that modulate inflammatory responses in preclinical models. Limited human pharmacokinetic data is available for either molecule, and the binding affinity of etifoxine for human TSPO is unknown. To allow for design of human challenge experiments, we derived pharmacokinetic data for orally administered etifoxine (50 mg 3 times daily) and XBD173 (90 mg once daily) and determined the binding affinity of etifoxine for TSPO. For XBD173, maximum plasma concentration and free fraction measurements predicted a maximal free concentration of 1.0 nM, which is similar to XBD173 binding affinity. For etifoxine, maximum plasma concentration and free fraction measurements predicted a maximal free concentration of 0.31 nM, substantially lower than the Ki for etifoxine in human brain derived here (7.8 μM, 95% CI 4.5-14.6 μM). We conclude that oral XBD173 dosing at 90 mg once daily will achieve pharmacologically relevant TSPO occupancy. However, the occupancy is too low for TSPO mediated effects after oral dosing of etifoxine at 50 mg 3 times daily.
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Affiliation(s)
- David R. Owen
- Department of Brain SciencesImperial College LondonLondon
| | | | | | - Gabrielle Grey
- Department of Brain SciencesImperial College LondonLondon
| | - Lina Aimola
- Department of Brain SciencesImperial College LondonLondon
| | | | - Paul M. Matthews
- Department of Brain SciencesImperial College LondonLondon
- UK Dementia Research Institute CentreImperial College LondonLondonUK
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14
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Yue YY, Wang YC, Liao ZX, Hu FY, Liu QY, Dong J, Zhong M, Chen MH, Pan YM, Zhong H, Shang J. Peripheral benzodiazepine receptor TSPO needs to be reconsidered before using as a drug target for a pigmentary disorder. FASEB J 2022; 36:e22454. [PMID: 35839067 DOI: 10.1096/fj.202101746rr] [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: 11/17/2021] [Revised: 06/19/2022] [Accepted: 07/06/2022] [Indexed: 11/11/2022]
Abstract
The peripheral benzodiazepine receptor (TSPO/PBR) is highly conserved among different species but with perplexing biochemical functions. Multiple ligands of TSPO show commendable regulatory activities in lots of biological functions, such as neuro-protection, cholesterol transport, and so on. These researches support that TSPO may be a potential target for disease treatment and drug development. Previous studies have shown that its ligands benzodiazepines show a satisfactory effect on melanogenic promotion. However, the potential application of TSPO in drug development for pigmentary disorder needs further investigation. In this study, we confirmed the melanogenesis induction of TSPO ligand, Ro5-4864 in mouse melanoma cell lines, human skin tissue, and zebrafish embryos by inducing melanin synthesis and melanosome transport. Molecular genetics and pharmacological studies showed that TSPO deficiency did not affect melanin production in B16F10 cells and zebrafish embryos, nor did it affect the melanin promotion effect of Ro5-4864. Whether or not TSPO exists, the expression of lots of melanogenesis-related proteins, such as TYR, TRP-1, DCT, Mlph, and Rab27 was upregulated with the Ro5-4864 administration. These results indicated that Ro5-4864 induces melanogenesis in a TSPO-independent manner, which is inconsistent with previous research. This research is a reminder that we need to be very careful during target validation in drug development.
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Affiliation(s)
- Yun-Yun Yue
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Yi-Chuan Wang
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Zi-Xian Liao
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Fang-Yuan Hu
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Qiu-Yan Liu
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Jing Dong
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Min Zhong
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Ming-Han Chen
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Yu-Min Pan
- School of Chemistry and Pharmacy, Guangxi Normal University, Guilin, China
| | - Hui Zhong
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Jing Shang
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China.,Jiangsu Key Laboratory of TCM Evaluation and Translational Research, China Pharmaceutical University, Nanjing, China.,NMPA Key Laboratory for Research and Evaluation of Cosmetics, National Institutes for Food and Drug Control, Beijing, China
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15
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The mitochondrial translocator protein (TSPO): a key multifunctional molecule in the nervous system. Biochem J 2022; 479:1455-1466. [PMID: 35819398 DOI: 10.1042/bcj20220050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 12/12/2022]
Abstract
Translocator protein (TSPO, 18 kDa), formerly known as peripheral benzodiazepine receptor, is an evolutionary well-conserved protein located on the outer mitochondrial membrane. TSPO is involved in a variety of fundamental physiological functions and cellular processes. Its expression levels are regulated under many pathological conditions, therefore, TSPO has been proposed as a tool for diagnostic imaging and an attractive therapeutic drug target in the nervous system. Several synthetic TSPO ligands have thus been explored as agonists and antagonists for innovative treatments as neuroprotective and regenerative agents. In this review, we provide state-of-the-art knowledge of TSPO functions in the brain and peripheral nervous system. Particular emphasis is placed on its contribution to important physiological functions such as mitochondrial homeostasis, energy metabolism and steroidogenesis. We also report how it is involved in neuroinflammation, brain injury and diseases of the nervous system.
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16
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Tournier BB, Tsartsalis S, Ceyzériat K, Fraser BH, Grégoire MC, Kövari E, Millet P. Astrocytic TSPO Upregulation Appears Before Microglial TSPO in Alzheimer's Disease. J Alzheimers Dis 2021; 77:1043-1056. [PMID: 32804124 PMCID: PMC7683091 DOI: 10.3233/jad-200136] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Background: In vivo PET/SPECT imaging of neuroinflammation is primarily based on the estimation of the 18 kDa-translocator-protein (TSPO). However, TSPO is expressed by different cell types which complicates the interpretation. Objective: The present study evaluates the cellular origin of TSPO alterations in Alzheimer’s disease (AD). Methods: The TSPO cell origin was evaluated by combining radioactive imaging approaches using the TSPO radiotracer [125I]CLINDE and fluorescence-activated cell sorting, in a rat model of AD (TgF344-AD) and in AD subjects. Results: In the hippocampus of TgF344-AD rats, TSPO overexpression not only concerns glial cells but the increase is visible at 12 and 24 months in astrocytes and only at 24 months in microglia. In the temporal cortex of AD subjects, TSPO upregulation involved only glial cells. However, the mechanism of this upregulation appears different with an increase in the number of TSPO binding sites per cell without cell proliferation in the rat, and a microglial cell population expansion with a constant number of binding sites per cell in human AD. Conclusion: These data indicate an earlier astrocyte intervention than microglia and that TSPO in AD probably is an exclusive marker of glial activity without interference from other TSPO-expressing cells. This observation indicates that the interpretation of TSPO imaging depends on the stage of the pathology, and highlights the particular role of astrocytes.
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Affiliation(s)
- Benjamin B Tournier
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Switzerland
| | - Stergios Tsartsalis
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Switzerland
| | - Kelly Ceyzériat
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Switzerland.,Division of Nuclear medicine, University Hospitals of Geneva, Switzerland
| | - Ben H Fraser
- ANSTO LifeSciences, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Sydney, NSW, Australia
| | - Marie-Claude Grégoire
- ANSTO LifeSciences, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Sydney, NSW, Australia
| | - Enikö Kövari
- Division of Geriatric Psychiatry, Department of Mental Health and Psychiatry, University Hospitals of Geneva, Switzerland.,Department of Psychiatry, University of Geneva, Switzerland
| | - Philippe Millet
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Switzerland.,Department of Psychiatry, University of Geneva, Switzerland
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17
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Wang J, Beecher K. TSPO: an emerging role in appetite for a therapeutically promising biomarker. Open Biol 2021; 11:210173. [PMID: 34343461 PMCID: PMC8331234 DOI: 10.1098/rsob.210173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
There is accumulating evidence that an obesogenic Western diet causes neuroinflammatory damage to the brain, which then promotes further appetitive behaviour. Neuroinflammation has been extensively studied by analysing the translocator protein of 18 kDa (TSPO), a protein that is upregulated in the inflamed brain following a damaging stimulus. As a result, there is a rich supply of TSPO-specific agonists, antagonists and positron emission tomography ligands. One TSPO ligand, etifoxine, is also currently used clinically for the treatment of anxiety with a minimal side-effect profile. Despite the neuroinflammatory pathogenesis of diet-induced obesity, and the translational potential of targeting TSPO, there is sparse literature characterizing the effect of TSPO on appetite. Therefore, in this review, the influence of TSPO on appetite is discussed. Three putative mechanisms for TSPO's appetite-modulatory effect are then characterized: the TSPO–allopregnanolone–GABAAR signalling axis, glucosensing in tanycytes and association with the synaptic protein RIM-BP1. We highlight that, in addition to its plethora of functions, TSPO is a regulator of appetite. This review ultimately suggests that the appetite-modulating function of TSPO should be further explored due to its potential therapeutic promise.
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Affiliation(s)
- Joshua Wang
- Addiction Neuroscience and Obesity Laboratory, School of Clinical Sciences, Faculty of Health, Translational Research Institute, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Kate Beecher
- Addiction Neuroscience and Obesity Laboratory, School of Clinical Sciences, Faculty of Health, Translational Research Institute, Queensland University of Technology, Brisbane, Queensland, Australia
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18
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Dominguini D, Steckert AV, Abatti MR, Generoso JS, Barichello T, Dal-Pizzol F. The Protective Effect of PK-11195 on Cognitive Impairment in Rats Survived of Polymicrobial Sepsis. Mol Neurobiol 2021; 58:2724-2733. [PMID: 33495933 DOI: 10.1007/s12035-021-02294-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 01/13/2021] [Indexed: 10/22/2022]
Abstract
Sepsis is an organ dysfunction caused by a host's unregulated response to infection, causing long-term brain dysfunction with microglial activation, the release of inflammatory components, and mitochondrial changes. Neuroinflammation can increase the expression of the 18-kD translocator protein (TSPO) in the mitochondria, leading to the activation of the microglia and the release of inflammatory components. The antagonist PK-11195 can modulate TSPO and reduce microglial activation and cognitive damage presented in an animal model of sepsis. The aim of this was to evaluate the effects of PK-11195 on long-term brain inflammation and cognitive impairment in an animal model of sepsis. Wistar rats, 60 days old, were submitted to cecal ligation and puncture (CLP) surgery, divided into groups control/saline, control/PK-11195, sepsis/saline, and sepsis/PK-11195. Immediately after surgery, the antagonist PK-11195 was administered at a dose of 3 mg/kg. Ten days after CLP surgery, the animals were submitted to behavioral tests and determination of brain inflammatory parameters. The sepsis/saline group presented cognitive damage. However, there was damage prevention in animals that received PK-11195. Besides, the sepsis increased the levels of cytokines and M1 microglia markers and caused oxidative damage. However, PK-11195 had the potential to decrease inflammation. These events show that the modulation of neuroinflammation during sepsis by PK-11195, possibly related to changes in TSPO, improves mitochondrial function in the animals' brains. In conclusion, the antagonist PK-11195 attenuated brain inflammation and prevented cognitive impairment in animals subjected to sepsis.
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Affiliation(s)
- Diogo Dominguini
- Laboratory of Experimental Pathophysiology, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, 88806-000, Brazil.
| | - Amanda V Steckert
- Laboratory of Experimental Pathophysiology, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, 88806-000, Brazil
| | - Mariane R Abatti
- Laboratory of Experimental Pathophysiology, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, 88806-000, Brazil
| | - Jaqueline S Generoso
- Laboratory of Experimental Pathophysiology, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, 88806-000, Brazil
| | - Tatiana Barichello
- Laboratory of Experimental Pathophysiology, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, 88806-000, Brazil
- Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Felipe Dal-Pizzol
- Laboratory of Experimental Pathophysiology, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, 88806-000, Brazil
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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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20
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De novo Neurosteroidogenesis in Human Microglia: Involvement of the 18 kDa Translocator Protein. Int J Mol Sci 2021; 22:ijms22063115. [PMID: 33803741 PMCID: PMC8003294 DOI: 10.3390/ijms22063115] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/06/2021] [Accepted: 03/15/2021] [Indexed: 12/14/2022] Open
Abstract
Neuroactive steroids are potent modulators of microglial functions and are capable of counteracting their excessive reactivity. This action has mainly been ascribed to neuroactive steroids released from other sources, as microglia have been defined unable to produce neurosteroids de novo. Unexpectedly, immortalized murine microglia recently exhibited this de novo biosynthesis; herein, de novo neurosteroidogenesis was characterized in immortalized human microglia. The results demonstrated that C20 and HMC3 microglial cells constitutively express members of the neurosteroidogenesis multiprotein machinery-in particular, the transduceosome members StAR and TSPO, and the enzyme CYP11A1. Moreover, both cell lines produce pregnenolone and transcriptionally express the enzymes involved in neurosteroidogenesis. The high TSPO expression levels observed in microglia prompted us to assess its role in de novo neurosteroidogenesis. TSPO siRNA and TSPO synthetic ligand treatments were used to reduce and prompt TSPO function, respectively. The TSPO expression downregulation compromised the de novo neurosteroidogenesis and led to an increase in StAR expression, probably as a compensatory mechanism. The pharmacological TSPO stimulation the de novo neurosteroidogenesis improved in turn the neurosteroid-mediated release of Brain-Derived Neurotrophic Factor. In conclusion, these results demonstrated that de novo neurosteroidogenesis occurs in human microglia, unravelling a new mechanism potentially useful for future therapeutic purposes.
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21
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Lan N, Liu Y, Juan Z, Zhang R, Ma B, Xie K, Sun L, Feng H, Sun M, Liu J. The TSPO-specific Ligand PK11195 Protects Against LPS-Induced Cognitive Dysfunction by Inhibiting Cellular Autophagy. Front Pharmacol 2021; 11:615543. [PMID: 33708121 PMCID: PMC7941270 DOI: 10.3389/fphar.2020.615543] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/16/2020] [Indexed: 11/13/2022] Open
Abstract
Perioperative neurocognitive disorders (PND) is a common postoperative neurological complication. Neuroinflammation is a major cause that leads to PND. Autophagy, an intracellular process of lysosomal degradation, plays an important role in the development and maintenance of nervous system. PK11195 is a classic translocator protein (TSPO) ligand, which can improve the cognitive function of rats. In this study, we evaluate the protective effect of PK11195 on the learning and memory of rats. A rat model of lipopolysaccharide (LPS)-induced cognitive dysfunction was established by intraperitoneal injection of LPS. Morris Water Maze (MWM), Western blot, qRT-PCR, confocal microscopy and transmission electron microscopy (TEM) were used to study the role of TSPO-specific ligand PK11195 in LPS-activated mitochondrial autophagy in rat hippocampus. We found that PK11195 ameliorated LPS-induced learning and memory impairment, as indicated by decreased escape latencies, swimming distances and increased target quadrant platform crossing times and swimming times during MWM tests. TSPO, ATG7, ATG5, LC3B and p62 protein and mRNA expression increased in the hippocampus of PND model rats. The hippocampal microglia of PND model rats also have severe mitochondrial damage, and a large number of autophagosomes and phagocytic vesicles can be seen. PK11195 pretreatment significantly decreased the expression of TSPO, ATG7, ATG5, LC3B and p62 protein and mRNA, as well as mitochondrial damage. These findings suggested that PK11195 may alleviate the damage of LPS-induced cognitive dysfunction of rats by inhibiting microglia activation and autophagy.
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Affiliation(s)
- Nannan Lan
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Yongxin Liu
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Zhaodong Juan
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Rui Zhang
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Baoyu Ma
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Keliang Xie
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Lina Sun
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Hao Feng
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Meng Sun
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Jianfeng Liu
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
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Savi FF, de Oliveira A, de Medeiros GF, Bozza FA, Michels M, Sharshar T, Dal-Pizzol F, Ritter C. What animal models can tell us about long-term cognitive dysfunction following sepsis: A systematic review. Neurosci Biobehav Rev 2020; 124:386-404. [PMID: 33309906 DOI: 10.1016/j.neubiorev.2020.12.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 01/28/2023]
Abstract
Survivors of sepsis often develop long-term cognitive impairments. This review aimed at exploring the results of the behavioral tools and tests which have been used to evaluate cognitive dysfunction in different animal models of sepsis. Two independent investigators searched for sepsis- and cognition-related keywords. 6323 publications were found, of which 355 were selected based on their title, and 226 of these were chosen based on manuscript review. LPS was used to induce sepsis in 171 studies, while CLP was used in 55 studies. Inhibitory avoidance was the most widely used method for assessing aversive memory, followed by fear conditioning and continuous multi-trial inhibitory avoidance. With regard to non-aversive memory, most studies used the water maze, open-field, object recognition, Y-maze, plus maze, and radial maze tests. Both CLP and LPS models of sepsis were effective in inducing short- and long-term behavioral impairment. Our findings help elucidate the mechanisms involved in the pathophysiology of sepsis-induced cognitive changes, as well as the available methods and tests used to study this in animal models.
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Affiliation(s)
- Felipe Figueredo Savi
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Brazil
| | - Alexandre de Oliveira
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Brazil
| | | | - Fernando Augusto Bozza
- Laboratório de Medicina Intensiva, Instituto Nacional de Infectologia Evandro Chagas (INI), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
| | - Monique Michels
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Brazil
| | - Tarek Sharshar
- Laboratoire de Neuropathologie Expérimentale, Institut Pasteur, Paris, France; Department of Neuro-Intensive Care Medicine, Sainte-Anne Hospital, Paris-Descartes University, Paris, France
| | - Felipe Dal-Pizzol
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Brazil; Laboratoire de Neuropathologie Expérimentale, Institut Pasteur, Paris, France
| | - Cristiane Ritter
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Brazil.
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23
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Zhang H, Ma L, Guo WZ, Jiao LB, Zhao HY, Ma YQ, Hao XM. TSPO ligand etifoxine attenuates LPS-induced cognitive dysfunction in mice. Brain Res Bull 2020; 165:178-184. [PMID: 33075418 DOI: 10.1016/j.brainresbull.2020.10.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 09/14/2020] [Accepted: 10/09/2020] [Indexed: 12/19/2022]
Abstract
The translocator protein (TSPO), once known as peripheral-type benzodiazepine receptor, was reported to be related with several physiological functions. Etifoxine is a clinically available anxiolytic drug, and has recently shown neuroprotective effects as a TSPO ligand. The aim of the present study was to investigate the influence of etifoxine on LPS-induced neuroinflammation and cognitive dysfunction. C57/BL6 male mice were injected with etifoxine (50 mg/kg, i.p.) three days before lipopolysaccharide (LPS, 500 μg/kg, i.p.) administration. Etifoxine pretreatment alleviated hippocampal inflammation, increased brain levels of progesterone, allopregnanolone and attenuated cognitive dysfunction in LPS-injected mice. While LPS increased expression of caspase-3 and decreased p-Akt/Akt, etifoxine returned caspase-3 and p-Akt/Akt to control levels. Finasteride, a 5α-reductase inhibitor that blocked allopregnanolone production, partially reversed the effects of etifoxine. We concluded that etifoxine exerted neuroprotective effects in LPS-induced neuroinflammation and the neuroprotection may be related with increase of neurosteroids synthesis and decrease of apoptosis.
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Affiliation(s)
- Hui Zhang
- Department of Neurosurgery, Air Force Medical Center of the Chinese PLA, Beijing, 100142, China.
| | - Li Ma
- Department of Anesthesiology, 7th Medical Center of the Chinese PLA General Hospital, Beijing, 100700, China
| | - Wen-Zhi Guo
- Department of Anesthesiology, 7th Medical Center of the Chinese PLA General Hospital, Beijing, 100700, China
| | - Lin-Bo Jiao
- Department of Anesthesiology, Beijing Shouda E.E.N.T Hospital, Beijing, 100070, China
| | - Hong-Yu Zhao
- Department of Anesthesiology, 7th Medical Center of the Chinese PLA General Hospital, Beijing, 100700, China
| | - Ya-Qun Ma
- Department of Anesthesiology, 7th Medical Center of the Chinese PLA General Hospital, Beijing, 100700, China
| | - Xue-Mei Hao
- Operating Room, 7th Medical Center of the Chinese PLA General Hospital, Beijing, 100700, China.
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24
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Ye C, Lin L, Zhang P, Chen Y, Huang J, Lin X. The protective effect of PK11195 on D-galactose-induced amnestic mild cognitive impairment in rats. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:1190. [PMID: 33241039 PMCID: PMC7576013 DOI: 10.21037/atm-20-6157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background This study aimed to investigate the preventive effect of translocator protein 18kDa (TSPO) ligand PK11195 on amnestic mild cognitive impairment (aMCI), as well as its influence on astrocytes, in order to identify effective ways to prevent aMCI. Methods Male SD rats were randomly divided into control group (n=10), aMCI group (n=10), PK11195 group (n=10), PK11195 + D-gal group (n=10). The preventive effect of PK11195 on aMCI in rats was evaluated. The cognitive function of rats in four different treatment groups was determined using the Morris water maze (MWM), as well as whole-brain pathology and immunofluorescence of rat brain tissue. Results The results of the MWM behavioral test showed that rats pre-treated with PK11195 had improved escape latency and a higher number of platform crossings compared with the aMCI model rats. PK11195 was also shown to prevent the D-galactose (D-gal)-induced senescence of pyramidal cells in the hippocampal CA1 region and to inhibit the apoptosis of astrocytes. At the same time, compared with the aMCI model rats, the TSPO in the brain tissue of rats pretreated with PK11195 had a lower distribution density. Conclusions Our results prove that PK11195 can effectively prevent D-gal-induced decline of learning and memory function as well as inhibit abnormal changes of related cells.
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Affiliation(s)
- Chen Ye
- Department of Anesthesiology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China.,Institute of Anesthesiology, Fujian Medical University, Fuzhou, China
| | - Lanying Lin
- Department of Anesthesiology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China.,Institute of Anesthesiology, Fujian Medical University, Fuzhou, China
| | - Peiling Zhang
- Department of Anesthesiology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China.,Institute of Anesthesiology, Fujian Medical University, Fuzhou, China
| | - Yi Chen
- Department of Anesthesiology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China.,Institute of Anesthesiology, Fujian Medical University, Fuzhou, China
| | - Jinghao Huang
- Department of Anesthesiology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China.,Institute of Anesthesiology, Fujian Medical University, Fuzhou, China
| | - Xianzhong Lin
- Department of Anesthesiology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China.,Institute of Anesthesiology, Fujian Medical University, Fuzhou, China
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25
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In Vivo TSPO Signal and Neuroinflammation in Alzheimer's Disease. Cells 2020; 9:cells9091941. [PMID: 32839410 PMCID: PMC7565089 DOI: 10.3390/cells9091941] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 12/15/2022] Open
Abstract
In the last decade, positron emission tomography (PET) and single-photon emission computed tomography (SPECT) in in vivo imaging has attempted to demonstrate the presence of neuroinflammatory reactions by measuring the 18 kDa translocator protein (TSPO) expression in many diseases of the central nervous system. We focus on two pathological conditions for which neuropathological studies have shown the presence of neuroinflammation, which translates in opposite in vivo expression of TSPO. Alzheimer's disease has been the most widely assessed with more than forty preclinical and clinical studies, showing overall that TSPO is upregulated in this condition, despite differences in the topography of this increase, its time-course and the associated cell types. In the case of schizophrenia, a reduction of TSPO has instead been observed, though the evidence remains scarce and contradictory. This review focuses on the key characteristics of TSPO as a biomarker of neuroinflammation in vivo, namely, on the cellular origin of the variations in its expression, on its possible biological/pathological role and on its variations across disease phases.
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26
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Qiu ZK, Liu X, Chen Y, Wu RJ, Guan SF, Pan YY, Wang QB, Tang D, Zhu T, Chen JS. Translocator protein 18 kDa: a potential therapeutic biomarker for post traumatic stress disorder. Metab Brain Dis 2020; 35:695-707. [PMID: 32172519 DOI: 10.1007/s11011-020-00548-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 02/10/2020] [Indexed: 11/11/2022]
Abstract
Post traumatic stress disorder (PTSD) is widely regarded as a stress-related and trauma disorder. The symptoms of PTSD are characterized as a spectrum of vulnerabilities after the exposure to an extremely traumatic stressor. Considering as one of complex mental disorders, little progress has been made toward its diagnostic biomarkers, despite the involvement of PTSD has been studied. Many studies into the underlying neurobiology of PTSD implicated the dysfunction of neurosteroids biosynthesis and neuorinflammatory processes. Translocator protein 18 kDa (TSPO) has been considered as one of the promising therapeutic biomarkers for neurological stress disorders (like PTSD, depression, anxiety, et al) without the benzodiazepine-like side effects. This protein participates in the formation of neurosteroids and modulation of neuroinflammation. The review outlines current knowledge involving the role of TSPO in the neuropathology of PTSD and the anti-PTSD-like effects of TSPO ligands.
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Affiliation(s)
- Zhi-Kun Qiu
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Xu Liu
- Pharmacy Department of Medical Supplies Center of General Hospital of Chinese People's Armed Police Forces, Beijing, 100039, People's Republic of China
| | - Yong Chen
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Rong-Jia Wu
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Shi-Feng Guan
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Yun-Yun Pan
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Qian-Bo Wang
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Dan Tang
- Guangdong Provincial Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of Pharmacy, Jinan University, Guangzhou, 510632, People's Republic of China
| | - Tao Zhu
- Guangdong Provincial Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of Pharmacy, Jinan University, Guangzhou, 510632, People's Republic of China
| | - Ji-Sheng Chen
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China.
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27
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Dimitrova-Shumkovska J, Krstanoski L, Veenman L. Diagnostic and Therapeutic Potential of TSPO Studies Regarding Neurodegenerative Diseases, Psychiatric Disorders, Alcohol Use Disorders, Traumatic Brain Injury, and Stroke: An Update. Cells 2020; 9:cells9040870. [PMID: 32252470 PMCID: PMC7226777 DOI: 10.3390/cells9040870] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/29/2020] [Accepted: 03/30/2020] [Indexed: 02/08/2023] Open
Abstract
Neuroinflammation and cell death are among the common symptoms of many central nervous system diseases and injuries. Neuroinflammation and programmed cell death of the various cell types in the brain appear to be part of these disorders, and characteristic for each cell type, including neurons and glia cells. Concerning the effects of 18-kDa translocator protein (TSPO) on glial activation, as well as being associated with neuronal cell death, as a response mechanism to oxidative stress, the changes of its expression assayed with the aid of TSPO-specific positron emission tomography (PET) tracers' uptake could also offer evidence for following the pathogenesis of these disorders. This could potentially increase the number of diagnostic tests to accurately establish the stadium and development of the disease in question. Nonetheless, the differences in results regarding TSPO PET signals of first and second generations of tracers measured in patients with neurological disorders versus healthy controls indicate that we still have to understand more regarding TSPO characteristics. Expanding on investigations regarding the neuroprotective and healing effects of TSPO ligands could also contribute to a better understanding of the therapeutic potential of TSPO activity for brain damage due to brain injury and disease. Studies so far have directed attention to the effects on neurons and glia, and processes, such as death, inflammation, and regeneration. It is definitely worthwhile to drive such studies forward. From recent research it also appears that TSPO ligands, such as PK11195, Etifoxine, Emapunil, and 2-Cl-MGV-1, demonstrate the potential of targeting TSPO for treatments of brain diseases and disorders.
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Affiliation(s)
- Jasmina Dimitrova-Shumkovska
- Department of Experimental Biochemistry, Institute of Biology, Faculty of Natural Sciences and Mathematics, University Ss Cyril and Methodius, Arhimedova 3, P.O. Box 162, 1000 Skopje, Republic of North Macedonia;
- Correspondence: (J.D.-S.); (L.V.)
| | - Ljupcho Krstanoski
- Department of Experimental Biochemistry, Institute of Biology, Faculty of Natural Sciences and Mathematics, University Ss Cyril and Methodius, Arhimedova 3, P.O. Box 162, 1000 Skopje, Republic of North Macedonia;
| | - Leo Veenman
- Technion-Israel Institute of Technology, Faculty of Medicine, Rappaport Institute of Medical Research, 1 Efron Street, P.O. Box 9697, Haifa 31096, Israel
- Correspondence: (J.D.-S.); (L.V.)
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28
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Giatti S, Diviccaro S, Serafini MM, Caruso D, Garcia-Segura LM, Viviani B, Melcangi RC. Sex differences in steroid levels and steroidogenesis in the nervous system: Physiopathological role. Front Neuroendocrinol 2020; 56:100804. [PMID: 31689419 DOI: 10.1016/j.yfrne.2019.100804] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 10/10/2019] [Accepted: 10/30/2019] [Indexed: 12/13/2022]
Abstract
The nervous system, in addition to be a target for steroid hormones, is the source of a variety of neuroactive steroids, which are synthesized and metabolized by neurons and glial cells. Recent evidence indicates that the expression of neurosteroidogenic proteins and enzymes and the levels of neuroactive steroids are different in the nervous system of males and females. We here summarized the state of the art of neuroactive steroids, particularly taking in consideration sex differences occurring in the synthesis and levels of these molecules. In addition, we discuss the consequences of sex differences in neurosteroidogenesis for the function of the nervous system under healthy and pathological conditions and the implications of neuroactive steroids and neurosteroidogenesis for the development of sex-specific therapeutic interventions.
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Affiliation(s)
- Silvia Giatti
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Silvia Diviccaro
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Melania Maria Serafini
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Donatella Caruso
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Luis Miguel Garcia-Segura
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain; Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | - Barbara Viviani
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Roberto C Melcangi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy.
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29
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Zhou D, Ji L, Chen Y. TSPO Modulates IL-4-Induced Microglia/Macrophage M2 Polarization via PPAR-γ Pathway. J Mol Neurosci 2019; 70:542-549. [PMID: 31879837 DOI: 10.1007/s12031-019-01454-1] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 11/20/2019] [Indexed: 02/03/2023]
Abstract
Microglia activation has been reported to be associated with pathogenesis of neuroinflammation, central nervous system damage, and degeneration diseases. With various damage-associated molecules released, M1 polarization of microglia emerges early after injury and followed by M2 polarization. In this study, we demonstrate using a primary microglia polarization model that, during the M2 polarization of microglia, the protein expression of translocator protein (TSPO) was decreased and peroxisome proliferator-activated receptor (PPAR-γ) activation was observed. In addition, we found TSPO antagonist PK11195 treatment enhanced PPAR-γ expression in M2-polarized microglia, while TSPO agonist FGIN-1-27 and TSPO overexpression in microglia significantly suppressed PPAR-γ expression in both the cytoplasm and nucleus. Then, real-time quantitative PCR was used to detect the expression of M2 polarization markers in microglia after TSPO ligand treatment, the data showed that PK11195 promoted the expression of CD206, Arg-1, YM-1, and FIZZ-1 induced by interleukin-4 (IL-4), and FGIN-1-27 and TSPO overexpression inhibited the expression of these molecules. Furthermore, the release of BDNF, CNTF-1, IGF-1, and NGF-1 from microglia was determined by enzyme-linked immunosorbent assay; these trophic factors showed similar trends with expression of M2 polarization markers. Levels of BDNF, CNTF-1, IGF-1, and NGF-1 were obviously upregulated by PK11195 and downregulated by FGIN-1-27 and TSPO overexpression. We propose that IL-4 in the hypoxic ischemia brain site induces the M2 polarization of microglia, and TSPO inhibits the M2 polarization and trophic factor release through PPAR-γ pathway.
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Affiliation(s)
- Dandan Zhou
- Department of Obstetrics and Gynecology, Yancheng First People's Hospital, Yancheng, 224005, Jiangsu, People's Republic of China
| | - Lei Ji
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Soochow University, Suzhou, 215123, Jiangsu, People's Republic of China
| | - Youguo Chen
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Soochow University, Suzhou, 215123, Jiangsu, People's Republic of China.
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30
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Arbo B, Ribeiro M, Garcia-Segura L. Development of new treatments for Alzheimer's disease based on the modulation of translocator protein (TSPO). Ageing Res Rev 2019; 54:100943. [PMID: 31430564 DOI: 10.1016/j.arr.2019.100943] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 08/07/2019] [Accepted: 08/15/2019] [Indexed: 12/27/2022]
Abstract
The increase in life expectancy of the world population is associated with a higher prevalence of neurodegenerative diseases. Alzheimer's Disease (AD) is the most common neurodegenerative disease, affecting currently 43 million people over the world. To date, most of the pharmacological interventions in AD are intended for the alleviation of some of its symptoms, and there are no effective treatments to inhibit the progression of the disease. Translocator protein (TSPO) is present in contact points between the outer and the inner mitochondrial membranes and is involved in the control of steroidogenesis, inflammation and apoptosis. In the last decade, studies have shown that TSPO ligands present neuroprotective effects in different experimental models of AD, both in vitro and in vivo. The aim of this review is to analyze the data provided by these studies and to discuss if TSPO could be a viable therapeutic target for the development of new treatments for AD.
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31
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Sheppard O, Coleman MP, Durrant CS. Lipopolysaccharide-induced neuroinflammation induces presynaptic disruption through a direct action on brain tissue involving microglia-derived interleukin 1 beta. J Neuroinflammation 2019; 16:106. [PMID: 31103036 PMCID: PMC6525970 DOI: 10.1186/s12974-019-1490-8] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 04/29/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Systemic inflammation has been linked to synapse loss and cognitive decline in human patients and animal models. A role for microglial release of pro-inflammatory cytokines has been proposed based on in vivo and primary culture studies. However, mechanisms are hard to study in vivo as specific microglial ablation is challenging and the extracellular fluid cannot be sampled without invasive methods. Primary cultures have different limitations as the intricate multicellular architecture in the brain is not fully reproduced. It is essential to confirm proposed brain-specific mechanisms of inflammatory synapse loss directly in brain tissue. Organotypic hippocampal slice cultures (OHSCs) retain much of the in vivo neuronal architecture, synaptic connections and diversity of cell types whilst providing convenient access to manipulate and sample the culture medium and observe cellular reactions. METHODS OHSCs were generated from P6-P9 C57BL/6 mice. Inflammation was induced via addition of lipopolysaccharide (LPS), and cultures were analysed for changes in synaptic proteins, gene expression and protein secretion. Microglia were selectively depleted using clodronate, and the effect of IL1β was assessed using a specific neutralising monoclonal antibody. RESULTS LPS treatment induced loss of the presynaptic protein synaptophysin without altering PSD95 or Aβ protein levels. Depletion of microglia prior to LPS application prevented the loss of synaptophysin, whilst microglia depletion after the inflammatory insult was partially effective, although less so than pre-emptive treatment, indicating a time-critical window in which microglia can induce synaptic damage. IL1β protein and mRNA were increased after LPS addition, with these effects also prevented by microglia depletion. Direct application of IL1β to OHSCs resulted in synaptophysin loss whilst pre-treatment with IL1β neutralising antibody prior to LPS addition prevented a significant loss of synaptophysin but may also impact basal synaptic levels. CONCLUSIONS The loss of synaptophysin in this system confirms LPS can act directly within brain tissue to disrupt synapses, and we show that microglia are the relevant cellular target when all major CNS cell types are present. By overcoming limitations of primary culture and in vivo work, our study strengthens the evidence for a key role of microglia-derived IL1β in synaptic dysfunction after inflammatory insult.
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Affiliation(s)
- Olivia Sheppard
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, E.D Adrian Building, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK
| | - Michael P Coleman
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, E.D Adrian Building, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK.,Signalling Programme, Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Claire S Durrant
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, E.D Adrian Building, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK. .,Signalling Programme, Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK.
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Lipopolysaccharide-Induced Neuroinflammation as a Bridge to Understand Neurodegeneration. Int J Mol Sci 2019; 20:ijms20092293. [PMID: 31075861 PMCID: PMC6539529 DOI: 10.3390/ijms20092293] [Citation(s) in RCA: 253] [Impact Index Per Article: 50.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/03/2019] [Accepted: 05/05/2019] [Indexed: 12/19/2022] Open
Abstract
A large body of experimental evidence suggests that neuroinflammation is a key pathological event triggering and perpetuating the neurodegenerative process associated with many neurological diseases. Therefore, different stimuli, such as lipopolysaccharide (LPS), are used to model neuroinflammation associated with neurodegeneration. By acting at its receptors, LPS activates various intracellular molecules, which alter the expression of a plethora of inflammatory mediators. These factors, in turn, initiate or contribute to the development of neurodegenerative processes. Therefore, LPS is an important tool for the study of neuroinflammation associated with neurodegenerative diseases. However, the serotype, route of administration, and number of injections of this toxin induce varied pathological responses. Thus, here, we review the use of LPS in various models of neurodegeneration as well as discuss the neuroinflammatory mechanisms induced by this toxin that could underpin the pathological events linked to the neurodegenerative process.
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33
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Insulin treatment protects the brain against neuroinflammation by reducing cerebral cytokines and modulating mitochondrial function. Brain Res Bull 2019; 149:120-128. [PMID: 31002914 DOI: 10.1016/j.brainresbull.2019.04.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 04/12/2019] [Accepted: 04/14/2019] [Indexed: 12/22/2022]
Abstract
In the central nervous system, glial cells protect the brain against neuronal stress by inducing inflammatory responses; namely, intracellular signaling and cytokine production. However, chronic inflammation is often associated with degenerative diseases that can damage hormone signaling and mitochondrial function. Lipopolysaccharide (LPS) induces neuroinflammation by stimulating the production of interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α); moreover, it generates oxidative stress and impairs cognitive functions. The aim of the present study was to assess the therapeutic efficacy of intracerebroventricular (i.c.v.) injections of insulin against neuroinflammation. Inflammation was first induced in male Wistar rats (60 days old, n = 12/group) through an intraperitoneal injection of 0.1 mg/kg LPS. The i.c.v. insulin treatment at a 0.5 mU dose was initiated 4 h later and administered once a day for 5 days. Thereafter, the spatial memory of the rats was assessed, and the hippocampus and cortex were later dissected for biochemical analyses. Our results showed that LPS induced cognitive function impairments, but the insulin treatment reversed these effects. Whereas the levels of brain-derived neurotrophic factor and beta-nerve growth factor in the hippocampus were not altered by LPS, they were decreased in the cortex by insulin. The IL-1β and TNF-α levels were increased in the cortex and hippocampus following exposure to LPS, but insulin reversed these effects. Evaluation of the H2O2levels and mitochondrial membrane potential revealed that LPS modulated mitochondrial function, an effect that was also reversed by insulin. Moreover, LPS induced oxidative stress by decreasing the superoxide dismutase and catalase activities and glutathione and sulfhydryl levels. Furthermore, the levels of oxidative stress probes/markers (i.e.,2',7'-dichlorodihydrofluoresceindiacetateand nitrite) were higher in the LPS-treated rats. These effects were all reversed in the cortex and hippocampus by insulin treatment. Our results suggest a potential role for insulin as a therapeutic drug against inflammatory diseases associated with mitochondrial dysfunction in the brain.
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Clemens V, Regen F, Le Bret N, Heuser I, Hellmann-Regen J. Retinoic Acid Enhances Apolipoprotein E Synthesis in Human Macrophages. J Alzheimers Dis 2019; 61:1295-1300. [PMID: 29376871 DOI: 10.3233/jad-170823] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Apolipoprotein E (ApoE) represents a pivotal target in Alzheimer's disease (AD) and is modulated through retinoic acid (RA), an endogenous neuroprotective and anti-inflammatory compound. A major source of ApoE are microglia, which are pathologically activated in AD. Activated microglia are known to block RA signaling. This suggests a vicious cycle between inflammation, RA signaling, and ApoE homeostasis in AD pathogenesis. To test this hypothesis, we investigated effects of RA and proinflammatory activation on ApoE synthesis in primary human macrophage-derived microglial-like cells. Our results indicate that proinflammatory activation attenuates ApoE synthesis, an effect blocked by RA.
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Affiliation(s)
- Vera Clemens
- Department of Psychiatry, Section Clinical Neurobiology, Campus Benjamin Franklin, Charité, University Medicine Berlin, Germany
| | - Francesca Regen
- Department of Psychiatry, Section Clinical Neurobiology, Campus Benjamin Franklin, Charité, University Medicine Berlin, Germany
| | - Nathalie Le Bret
- Department of Psychiatry, Section Clinical Neurobiology, Campus Benjamin Franklin, Charité, University Medicine Berlin, Germany
| | - Isabella Heuser
- Department of Psychiatry, Section Clinical Neurobiology, Campus Benjamin Franklin, Charité, University Medicine Berlin, Germany
| | - Julian Hellmann-Regen
- Department of Psychiatry, Section Clinical Neurobiology, Campus Benjamin Franklin, Charité, University Medicine Berlin, Germany
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35
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Christensen A, Pike CJ. TSPO ligand PK11195 improves Alzheimer-related outcomes in aged female 3xTg-AD mice. Neurosci Lett 2018; 683:7-12. [PMID: 29925037 DOI: 10.1016/j.neulet.2018.06.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 06/15/2018] [Indexed: 11/18/2022]
Abstract
Alzheimer's disease (AD) pathogenesis is a multifactorial process that involves numerous pathways within the central nervous system. Thus, interventions that interact with several disease-related pathways may offer an increased opportunity for successful prevention and treatment of AD. Translocator protein 18 kD (TSPO) is a mitochondrial protein that is associated with regulation of many cellular processes including inflammation, steroid synthesis, apoptosis, and mitochondrial respiration. Although TSPO ligands have been shown to be protective in several neurodegenerative paradigms, little work has been done to assess their potential as treatments for AD. Female 3xTg-AD mice were administered the TSPO ligand PK11195 once weekly for 5 weeks beginning at 16 months, an age characterized by extensive β-amyloid pathology and behavioral impairments. Animals treated with PK11195 showed improvements in behavior and modest reductions of in both soluble and deposited β-amyloid. The finding that short-term PK11195 treatment was effective in improving both behavioral and pathological outcomes in a model of late-stage AD supports further investigation of TSPO ligands as potential therapeutics for the treatment of AD.
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Affiliation(s)
- Amy Christensen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA USA
| | - Christian J Pike
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA USA.
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36
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Chowdhury AA, Gawali NB, Munshi R, Juvekar AR. Trigonelline insulates against oxidative stress, proinflammatory cytokines and restores BDNF levels in lipopolysaccharide induced cognitive impairment in adult mice. Metab Brain Dis 2018; 33:681-691. [PMID: 29277879 DOI: 10.1007/s11011-017-0147-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 11/07/2017] [Indexed: 10/18/2022]
Abstract
Neuroinflammation is said to play a pivotal role in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease (AD). Trigonelline (TRG) is a naturally occurring alkaloid, commonly isolated from fenugreek and coffee beans. In the present study, we investigated whether TRG exerts neuroprotective action against LPS mediated cognitive impairment. Mice pretreated with TRG (50 and 100 mg/kg po) were administered with LPS (250 μg/kg ip) for 7 days. Memory was assessed in the Morris water maze (MWM) and Y maze. LPS administration caused poor memory retention in MWM and Y maze paradigms, and resulted in marked oxidative stress as evidenced by decrease in superoxide dismutase (SOD), reduced glutathione (GSH) levels and increased lipid peroxidation in the hippocampus and cortex. Cholinergic involvement during neuroinflammation was evaluated by measuring levels of acetylcholinesterase (AChE) enzyme. TRG treatment at both the doses reversed LPS induced behavioral and memory disturbances, significantly decreased the oxidative stress and AChE levels in both the hippocampus and cortex. LPS administration also elevated the tumour necrosis factor (TNF-α) and interleukin -6 (IL-6) levels, whereas brain derived neurotrophic factor (BDNF) levels were significantly depleted. TRG pretreatment led to decreased TNF-α and IL-6 levels and caused a significant upregulation of BDNF levels. In conclusion, present study highlights the promising neuroprotective role of TRG against LPS mediated cognitive impairment which could be attributed to reduced oxidative stress, inhibition of proinflammatory cytokines and restoration of BDNF levels.
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Affiliation(s)
- Amrita A Chowdhury
- Department of Pharmaceutical Sciences and Technology (DPST), Institute of Chemical Technology (ICT), N. P. Marg, Matunga (E), Mumbai, -400019, India
| | - Nitin B Gawali
- Department of Pharmaceutical Sciences and Technology (DPST), Institute of Chemical Technology (ICT), N. P. Marg, Matunga (E), Mumbai, -400019, India
| | - Renuka Munshi
- Department of Clinical Pharmacology, B. Y. L. Nair Charitable Hospital and Topiwala National Medical College, Dr. A. L. Nair Road, Mumbai, 400008, India
| | - Archana R Juvekar
- Department of Pharmaceutical Sciences and Technology (DPST), Institute of Chemical Technology (ICT), N. P. Marg, Matunga (E), Mumbai, -400019, India.
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Notter T, Coughlin JM, Gschwind T, Weber-Stadlbauer U, Wang Y, Kassiou M, Vernon AC, Benke D, Pomper MG, Sawa A, Meyer U. Translational evaluation of translocator protein as a marker of neuroinflammation in schizophrenia. Mol Psychiatry 2018; 23:323-334. [PMID: 28093569 DOI: 10.1038/mp.2016.248] [Citation(s) in RCA: 140] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 10/14/2016] [Accepted: 11/28/2016] [Indexed: 02/08/2023]
Abstract
Positron emission tomography (PET) imaging with radiotracers that target translocator protein 18 kDa (TSPO) has become a popular approach to assess putative neuroinflammatory processes and associated microglia activation in psychotic illnesses. It remains unclear, however, whether TSPO imaging can accurately capture low-grade inflammatory processes such as those present in schizophrenia and related disorders. Therefore, we evaluated the validity of TSPO as a disease-relevant marker of inflammation using a translational approach, which combined neurodevelopmental and neurodegenerative mouse models with PET imaging in patients with recent-onset schizophrenia and matched controls. Using an infection-mediated neurodevelopmental mouse model, we show that schizophrenia-relevant behavioral abnormalities and increased inflammatory cytokine expression are associated with reduced prefrontal TSPO levels. On the other hand, TSPO was markedly upregulated in a mouse model of acute neurodegeneration and reactive gliosis, which was induced by intrahippocampal injection of kainic acid. In both models, the changes in TSPO levels were not restricted to microglia but emerged in various cell types, including microglia, astrocytes and vascular endothelial cells. Human PET imaging using the second-generation TSPO radiotracer [11C]DPA-713 revealed a strong trend towards reduced TSPO binding in the middle frontal gyrus of patients with recent-onset schizophrenia, who were previously shown to display increased levels of inflammatory cytokines in peripheral and central tissues. Together, our findings challenge the common assumption that central low-grade inflammation in schizophrenia is mirrored by increased TSPO expression or ligand binding. Our study further underscores the need to interpret altered TSPO binding in schizophrenia with caution, especially when measures of TSPO are not complemented with other markers of inflammation. Unless more selective microglial markers are available for PET imaging, quantification of cytokines and other inflammatory biomarkers, along with their molecular signaling pathways, may be more accurate in attempts to characterize inflammatory profiles in schizophrenia and other mental disorders that lack robust reactive gliosis.
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Affiliation(s)
- T Notter
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - J M Coughlin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, MD, USA
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - T Gschwind
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - U Weber-Stadlbauer
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland
| | - Y Wang
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - M Kassiou
- School of Chemistry, The University of Sydney, Sydney, NSW, Australia
- Discipline of Medical Radiation Sciences, The University of Sydney, Sydney, NSW, Australia
| | - A C Vernon
- MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK
- King's College London, Institute of Psychiatry Psychology and Neuroscience, Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, London, UK
| | - D Benke
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - M G Pomper
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, MD, USA
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - A Sawa
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - U Meyer
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
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38
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McNeela AM, Bernick C, Hines RM, Hines DJ. TSPO regulation in reactive gliotic diseases. J Neurosci Res 2018; 96:978-988. [PMID: 29315754 DOI: 10.1002/jnr.24212] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 11/29/2017] [Accepted: 12/06/2017] [Indexed: 12/19/2022]
Abstract
The brain is the most metabolically active organ in the body. This high metabolic demand is apparent in that 60% of the brain is comprised of mitochondria-enriched cells. A disruption of the brain's ability to meet this immense metabolic demand is central to the pathogenesis of a multitude of neurological disorders, which range from depression to Alzheimer's disease. Central to these pathologies are glial signaling and energy metabolism cascades regulating apoptosis and inflammation. Thus, diseases causing inflammation and disruption of metabolism can be correlated with glial reactivity. Acutely, reactive gliosis provides a mechanism for limiting the progression of a disease. Following chronic activation, the ability of reactive gliosis to limit disease progression decreases and, in some cases, transitions into a harmful state. The necessity for a noninvasive biomarker of disease in the brain has linked reactive gliosis with an upregulation of translocator protein (TSPO). TSPO is an 18kDa protein that is both a therapeutic target for multiple acute and chronic neuroinflammatory diseases and the leading biomarker for Alzheimer's disease. Although a central function of TSPO is not well known, the protein was named for its ability to translocate cholesterol. Increased TSPO expression is an indicator of disrupted metabolic activity and increased reactive oxygen production. The changes in TSPO expression levels both temporally and spatially relate to the pathogenesis of stroke, Alzheimer's disease, traumatic brain injury, and depression. Therefore, research into the basic function and potential therapeutics targeting TSPO will have broad implications for many diseases of the brain.
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Affiliation(s)
- Adam M McNeela
- Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV
| | - Charles Bernick
- Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV
| | - Rochelle M Hines
- Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV
| | - Dustin J Hines
- Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV
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Barichello T, Simões LR, Collodel A, Giridharan VV, Dal-Pizzol F, Macedo D, Quevedo J. The translocator protein (18 kDa) and its role in neuropsychiatric disorders. Neurosci Biobehav Rev 2017; 83:183-199. [DOI: 10.1016/j.neubiorev.2017.10.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 09/20/2017] [Accepted: 10/10/2017] [Indexed: 02/08/2023]
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40
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Regulation of Mitochondrial, Cellular, and Organismal Functions by TSPO. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2017; 82:103-136. [PMID: 29413517 DOI: 10.1016/bs.apha.2017.09.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In 1999, the enigma of the 18kDa mitochondrial translocator protein (TSPO), also known as the peripheral-type benzodiazepine receptor, was the seeming disparity of the many functions attributed to TSPO, ranging from the potential of TSPO acting as a housekeeping gene at molecular biological levels to adaptations to stress, and even involvement in higher emotional and cognitive functioning, such as anxiety and depression. In the years since then, knowledge regarding the many functions modulated by TSPO has expanded, and understanding has deepened. In addition, new functions could be firmly associated with TSPO, such as regulation of programmed cell death and modulation of gene expression. Interestingly, control by the mitochondrial TSPO over both of these life and death functions appears to include Ca++ homeostasis, generation of reactive oxygen species (ROS), and ATP production. Other mitochondrial functions under TSPO control are considered to be steroidogenesis and tetrapyrrole metabolism. As TSPO effects on gene expression and on programmed cell death can be related to the wide range of functions that can be associated with TSPO, several of these five elements of Ca++, ROS, ATP, steroids, and tetrapyrroles may indeed form the basis of TSPO's capability to operate as a multifunctional housekeeping gene to maintain homeostasis of the cell and of the whole multicellular organism.
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41
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Zhao WX, Zhang JH, Cao JB, Wang W, Wang DX, Zhang XY, Yu J, Zhang YY, Zhang YZ, Mi WD. Acetaminophen attenuates lipopolysaccharide-induced cognitive impairment through antioxidant activity. J Neuroinflammation 2017; 14:17. [PMID: 28109286 PMCID: PMC5251335 DOI: 10.1186/s12974-016-0781-6] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 12/16/2016] [Indexed: 12/20/2022] Open
Abstract
Background Considerable evidence has shown that neuroinflammation and oxidative stress play an important role in the pathophysiology of postoperative cognitive dysfunction (POCD) and other progressive neurodegenerative disorders. Increasing evidence suggests that acetaminophen (APAP) has unappreciated antioxidant and anti-inflammatory properties. However, the impact of APAP on the cognitive sequelae of inflammatory and oxidative stress is unknown. The objective of this study is to explore whether APAP could have neuroprotective effects on lipopolysaccharide (LPS)-induced cognitive impairment in mice. Methods A mouse model of LPS-induced cognitive impairment was established to evaluate the neuroprotective effects of APAP against LPS-induced cognitive impairment. Adult C57BL/6 mice were treated with APAP half an hour prior to intracerebroventricular microinjection of LPS and every day thereafter, until the end of the study period. The Morris water maze was used to assess cognitive function from postinjection days 1 to 3. Animal behavioural tests as well as pathological and biochemical assays were performed to evaluate LPS-induced hippocampal damage and the neuroprotective effect of APAP. Results Mice treated with LPS exhibited impaired performance in the Morris water maze without changing spontaneous locomotor activity, which was ameliorated by treatment with APAP. APAP suppressed the accumulation of pro-inflammatory cytokines and microglial activation induced by LPS in the hippocampus. In addition, APAP increased SOD activity, reduced MDA levels, modulated glycogen synthase kinase 3β (GSK3β) activity and elevated brain-derived neurotrophic factor (BDNF) expression in the hippocampus. Moreover, APAP significantly decreased the Bax/Bcl-2 ratio and neuron apoptosis in the hippocampus of LPS-treated mice. Conclusions Our results suggest that APAP may possess a neuroprotective effect against LPS-induced cognitive impairment and inflammatory and oxidative stress via mechanisms involving its antioxidant and anti-inflammatory properties, as well as its ability to inhibit the mitochondrial permeability transition (MPT) pore and the subsequent apoptotic pathway.
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Affiliation(s)
- Wei-Xing Zhao
- Anesthesia and Operation Center, Chinese PLA General Hospital, 28th Fuxing Road, Haidian District, Beijing, 100853, China
| | - Jun-Han Zhang
- The Second Affiliated Hospital of Xiangya School of Medicine, Central South University, Changsha, 410008, China
| | - Jiang-Bei Cao
- Anesthesia and Operation Center, Chinese PLA General Hospital, 28th Fuxing Road, Haidian District, Beijing, 100853, China
| | - Wei Wang
- Anesthesia and Operation Center, Chinese PLA General Hospital, 28th Fuxing Road, Haidian District, Beijing, 100853, China.,Department of Anesthesiology, The General Hospital of the PLA Rocket Force, Beijing, 100088, China
| | - Dong-Xin Wang
- Department of Anesthesiology and Surgical Intensive Care, Peking University First Hospital, Beijing, 100034, China
| | - Xiao-Ying Zhang
- Anesthesia and Operation Center, Chinese PLA General Hospital, 28th Fuxing Road, Haidian District, Beijing, 100853, China
| | - Jun Yu
- Anesthesia and Operation Center, Chinese PLA General Hospital, 28th Fuxing Road, Haidian District, Beijing, 100853, China
| | - Yong-Yi Zhang
- Anesthesia and Operation Center, Chinese PLA General Hospital, 28th Fuxing Road, Haidian District, Beijing, 100853, China
| | - You-Zhi Zhang
- Institute of Pharmacology and Toxicology, Beijing Key laboratory of Neuropsychopharmacology, 27th Taiping Road, Haidian District, Beijing, 100850, China
| | - Wei-Dong Mi
- Anesthesia and Operation Center, Chinese PLA General Hospital, 28th Fuxing Road, Haidian District, Beijing, 100853, China.
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Wang W, Zhang L, Zhang X, Xue R, Li L, Zhao W, Fu Q, Mi W, Li Y. Lentiviral-Mediated Overexpression of the 18 kDa Translocator Protein (TSPO) in the Hippocampal Dentate Gyrus Ameliorates LPS-Induced Cognitive Impairment in Mice. Front Pharmacol 2016; 7:384. [PMID: 27803668 PMCID: PMC5068146 DOI: 10.3389/fphar.2016.00384] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 10/03/2016] [Indexed: 12/12/2022] Open
Abstract
The 18 kDa translocator protein (TSPO) is involved in the immune/inflammatory response. However, the exact role that TSPO plays in neuroinflammation-induced cognitive impairment is still elusive. The purpose of our present study was to investigate the effects of lentiviral-mediated hippocampal overexpression of the TSPO in a mouse model of LPS-induced cognitive impairment. We established a mouse cognitive impairment model using systematic daily administration of lipopolysaccharide (LPS) (0.5 mg/kg). Microinjection of the dentate gyrus of the mouse with lentiviral vectors, which contained a cDNA targeting TSPO (Lv-TSPO), resulted in a significant increase in TSPO expression and allopregnanolone production. Mice treated with LPS showed cognitive deficits in the novel object recognition test and the Morris water maze test that could be ameliorated by TSPO overexpression. In addition, TSPO overexpression reversed LPS-induced microglial activation and accumulation of pro-inflammatory cytokines, including IL-1β, IL-6, and TNF-α. Moreover, TSPO overexpression attenuated the LPS-induced impairment of hippocampal neurogenesis. Our results suggest that local overexpression of TSPO in the hippocampal dentate gyrus alleviated LPS-induced cognitive deficits, and its effects might be mediated by the attenuation of inflammatory cytokines, inhibition of microglial activation, and promotion of neurogenesis.
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Affiliation(s)
- Wei Wang
- Anesthesia and Operation Center, Chinese PLA General HospitalBeijing, China; Department of New Drug Evaluation, Beijing Institute of Pharmacology and ToxicologyBeijing, China; Department of Anesthesiology, The General Hospital of the PLA Rocket ForceBeijing, China
| | - Liming Zhang
- Department of New Drug Evaluation, Beijing Institute of Pharmacology and Toxicology Beijing, China
| | - Xiaoying Zhang
- Anesthesia and Operation Center, Chinese PLA General Hospital Beijing, China
| | - Rui Xue
- Department of New Drug Evaluation, Beijing Institute of Pharmacology and Toxicology Beijing, China
| | - Lei Li
- Department of Postgraduates, Hebei North University Zhangjiakou, China
| | - Weixing Zhao
- Anesthesia and Operation Center, Chinese PLA General Hospital Beijing, China
| | - Qiang Fu
- Anesthesia and Operation Center, Chinese PLA General Hospital Beijing, China
| | - Weidong Mi
- Anesthesia and Operation Center, Chinese PLA General Hospital Beijing, China
| | - Yunfeng Li
- Department of New Drug Evaluation, Beijing Institute of Pharmacology and Toxicology Beijing, China
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Selvaraj V, Tu LN. Current status and future perspectives: TSPO in steroid neuroendocrinology. J Endocrinol 2016; 231:R1-R30. [PMID: 27422254 DOI: 10.1530/joe-16-0241] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 07/15/2016] [Indexed: 12/21/2022]
Abstract
The mitochondrial translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor (PBR), has received significant attention both as a diagnostic biomarker and as a therapeutic target for different neuronal disease pathologies. Recently, its functional basis believed to be mediating mitochondrial cholesterol import for steroid hormone production has been refuted by studies examining both in vivo and in vitro genetic Tspo-deficient models. As a result, there now exists a fundamental gap in the understanding of TSPO function in the nervous system, and its putative pharmacology in neurosteroid production. In this review, we discuss several recent findings in steroidogenic cells that are in direct contradiction to previous studies, and necessitate a re-examination of the purported role for TSPO in de novo neurosteroid biosynthesis. We critically examine the pharmacological effects of different TSPO-binding drugs with particular focus on studies that measure neurosteroid levels. We highlight the basis of key misconceptions regarding TSPO that continue to pervade the literature, and the need for interpretation with caution to avoid negative impacts. We also summarize the emerging perspectives that point to new directions that need to be investigated for understanding the molecular function of TSPO, only after which the true potential of this therapeutic target in medicine may be realized.
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Affiliation(s)
- Vimal Selvaraj
- Department of Animal ScienceCornell University, Ithaca, New York, USA
| | - Lan N Tu
- Department of Animal ScienceCornell University, Ithaca, New York, USA
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Betlazar C, Middleton RJ, Banati RB, Liu GJ. The impact of high and low dose ionising radiation on the central nervous system. Redox Biol 2016; 9:144-156. [PMID: 27544883 PMCID: PMC4993858 DOI: 10.1016/j.redox.2016.08.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 08/06/2016] [Accepted: 08/09/2016] [Indexed: 12/12/2022] Open
Abstract
Responses of the central nervous system (CNS) to stressors and injuries, such as ionising radiation, are modulated by the concomitant responses of the brains innate immune effector cells, microglia. Exposure to high doses of ionising radiation in brain tissue leads to the expression and release of biochemical mediators of ‘neuroinflammation’, such as pro-inflammatory cytokines and reactive oxygen species (ROS), leading to tissue destruction. Contrastingly, low dose ionising radiation may reduce vulnerability to subsequent exposure of ionising radiation, largely through the stimulation of adaptive responses, such as antioxidant defences. These disparate responses may be reflective of non-linear differential microglial activation at low and high doses, manifesting as an anti-inflammatory or pro-inflammatory functional state. Biomarkers of pathology in the brain, such as the mitochondrial Translocator Protein 18 kDa (TSPO), have facilitated in vivo characterisation of microglial activation and ‘neuroinflammation’ in many pathological states of the CNS, though the exact function of TSPO in these responses remains elusive. Based on the known responsiveness of TSPO expression to a wide range of noxious stimuli, we discuss TSPO as a potential biomarker of radiation-induced effects. Ionising radiation can modulate responses of microglial cells in the CNS. High doses can induce ROS formation, oxidative stress and neuroinflammation. Low doses can mitigate tissue damage via antioxidant defences. TSPO as a potential biomarker and modulator of radiation induced effects in the CNS. Non-linear differential microglial activation to high and low doses is proposed.
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Affiliation(s)
- Calina Betlazar
- Bioanalytics group, Life Sciences, Australian Nuclear Science and Technology Organisation (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234, Australia; Discipline of Medical Imaging & Radiation Sciences, Faculty of Health Sciences, The University of Sydney, 75 East Street, Lidcombe, NSW 2141, Australia
| | - Ryan J Middleton
- Bioanalytics group, Life Sciences, Australian Nuclear Science and Technology Organisation (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Richard B Banati
- Bioanalytics group, Life Sciences, Australian Nuclear Science and Technology Organisation (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234, Australia; Discipline of Medical Imaging & Radiation Sciences, Faculty of Health Sciences, The University of Sydney, 75 East Street, Lidcombe, NSW 2141, Australia.
| | - Guo-Jun Liu
- Bioanalytics group, Life Sciences, Australian Nuclear Science and Technology Organisation (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234, Australia; Discipline of Medical Imaging & Radiation Sciences, Faculty of Health Sciences, The University of Sydney, 75 East Street, Lidcombe, NSW 2141, Australia.
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Augmented expression of TSPO after intracerebral hemorrhage: a role in inflammation? J Neuroinflammation 2016; 13:151. [PMID: 27315802 PMCID: PMC4912814 DOI: 10.1186/s12974-016-0619-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 06/09/2016] [Indexed: 02/08/2023] Open
Abstract
Background Intracerebral hemorrhage (ICH) is a potentially fatal stroke subtype accounting for 10–15 % of all strokes. Despite neurosurgical intervention and supportive care, the 30-day mortality rate remains 30–50 % with ICH survivors frequently displaying neurological impairment and requiring long-term assisted care. Although accumulating evidence demonstrates the role of neuroinflammation in secondary brain injury and delayed fatality after ICH, the molecular regulators of neuroinflammation remain poorly defined after ICH. Methods In the present study, ICH was induced in CD1 male mice by collagenase injection method and given the emerging role of TSPO (18-kDa translocator protein) in neuroinflammation, immunofluorescence staining of brain sections was performed to characterize the temporal expression pattern and cellular and subcellular localization of TSPO after ICH. Further, both genetic and pharmacological studies were employed to assess the functional role of TSPO in neuroinflammation. Results The expression of TSPO was found to be increased in the peri-hematomal brain region 1 to 7 days post-injury, peaking on day 3 to day 5 in comparison to sham. Further, the TSPO expression was mostly observed in microglia/macrophages, the inflammatory cells of the central nervous system, suggesting an unexplored role of TSPO in neuroinflammatory responses after ICH. Further, the subcellular localization studies revealed prominent perinuclear expression of TSPO after ICH. Moreover, both genetic and pharmacological studies revealed a regulatory role of TSPO in the release of pro-inflammatory cytokines in a macrophage cell line, RAW 264.7. Conclusions Altogether, the data suggest that TSPO induction after ICH could be an intrinsic mechanism to prevent an exacerbated inflammatory response and raise the possibility of targeting TSPO for the attenuation of secondary brain injury after ICH.
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