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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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Gao S, Li N, Wang Y, Lin Z, Zhu Y, Xu J, Zhang Q, Zhu C, Zhou Y, Zhou J, Shen X. Inhibition of vascular endothelial growth factor alleviates neovascular retinopathy with regulated neurotrophic/proinflammatory cytokines through the modulation of DBI-TSPO signaling. FASEB J 2022; 36:e22367. [PMID: 35639422 DOI: 10.1096/fj.202101294rrr] [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: 08/14/2021] [Revised: 04/17/2022] [Accepted: 05/10/2022] [Indexed: 11/11/2022]
Abstract
Diazepam binding inhibitor (DBI)-translocator protein (18kDa) (TSPO) signaling in the retina was reported to possess coordinated macroglia-microglia interactions. We investigated DBI-TSPO signaling and its correlation with vascular endothelial growth factor (VEGF), neurotrophic or inflammatory cytokines in neovascular retinopathy, and under hypoxic conditions. The vitreous expression of DBI, VEGF, nerve growth factor (NGF), and interleukin-1beta (IL-1β) were examined in proliferative diabetic retinopathy (PDR) patients with or without anti-VEGF therapy and nondiabetic controls. Retinal DBI-TSPO signaling and the effect of the anti-VEGF agent were evaluated in a mouse model of oxygen-induced retinopathy (OIR). Interactions between Müller cell-derived VEGF and DBI, as well as cocultured microglial cells under hypoxic conditions, were studied, using Western blot, real-time RT-PCR, enzyme-linked immunosorbent assay (ELISA), flow cytometry, and immunofluorescent labeling. Results showed that vitreous levels of DBI, VEGF, NGF, and IL-1β were significantly higher in PDR patients compared with controls, which further changed after anti-VEGF therapy. A statistical association was found between vitreous DBI and VEGF, NGF, IL-1β, and age. The application of the anti-VEGF agent in the OIR model induced retinal expression of DBI and NGF, and attenuated inflammation and microglial cell activation. Inhibition of Müller cell-derived VEGF could increase its DBI expression under hypoxic conditions, while the DBI-TSPO signaling pathway is essential for anti-VEGF agents exerting anti-inflammatory and neuroprotective effects, as well as limiting inflammatory magnitude, promoting its neurotrophin production and anti-inflammatory (M2) polarization in microglial cells. These findings suggest the beneficial effect of anti-VEGF therapy on inflammation and neurotrophy of retinal glial cells through modulation of the DBI-TSPO signaling pathway.
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Affiliation(s)
- Shuang Gao
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Na Li
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yanuo Wang
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Zhongjing Lin
- Department of Ophthalmology, Renji Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yanji Zhu
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jianmin Xu
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Qiong Zhang
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Caihong Zhu
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yingming Zhou
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jia Zhou
- Department of Ophthalmology, Ruijin Hospital, LuWan Branch, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xi Shen
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
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MicroPET Imaging Assessment of Brain Tau and Amyloid Deposition in 6 × Tg Alzheimer’s Disease Model Mice. Int J Mol Sci 2022; 23:ijms23105485. [PMID: 35628296 PMCID: PMC9146140 DOI: 10.3390/ijms23105485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/04/2022] [Accepted: 05/09/2022] [Indexed: 11/23/2022] Open
Abstract
Alzheimer’s disease (AD) is characterized by the deposition of extracellular amyloid plaques and intracellular accumulation of neurofibrillary tangles (NFT). Amyloid beta (Aβ) and tau imaging are widely used for diagnosing and monitoring AD in clinical settings. We evaluated the pathology of a recently developed 6 × Tg − AD (6 × Tg) mouse model by crossbreeding 5 × FAD mice with mice expressing mutant (P301L) tau protein using micro-positron emission tomography (PET) image analysis. PET studies were performed in these 6 × Tg mice using [18F]Flutemetamol, which is an amyloid PET radiotracer; [18F]THK5351 and [18F]MK6240, which are tau PET radiotracers; moreover, [18F]DPA714, which is a translocator protein (TSPO) radiotracer, and comparisons were made with age-matched mice of their respective parental strains. We compared group differences in standardized uptake value ratio (SUVR), kinetic parameters, biodistribution, and histopathology. [18F]Flutemetamol images showed prominent cortical uptake and matched well with 6E10 staining images from 2-month-old 6 × Tg mice. [18F]Flutemetamol images showed a significant correlation with [18F]DPA714 in the cortex and hippocampus. [18F]THK5351 images revealed prominent hippocampal uptake and matched well with AT8 immunostaining images in 4-month-old 6 × Tg mice. Moreover, [18F]THK5351 images were confirmed using [18F]MK6240, which revealed significant correlations in the cortex and hippocampus. Uptake of [18F]THK5351 or [18F]MK6240 was highly correlated with [18F]Flutemetamol in 4-month-old 6 × Tg mice. In conclusion, PET imaging revealed significant age-related uptake of Aβ, tau, and TSPO in 6 × Tg mice, which was highly correlated with age-dependent pathology.
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Translocator Protein Regulate Polarization Phenotype Transformation of Microglia after Cerebral Ischemia-reperfusion Injury. Neuroscience 2021; 480:203-216. [PMID: 34624453 DOI: 10.1016/j.neuroscience.2021.09.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/26/2021] [Accepted: 09/28/2021] [Indexed: 12/12/2022]
Abstract
Microglia cells are activated after cerebral ischemia-reperfusion injury (CIRI), playing a dual role in aggravating the injury or promoting tissue repair by polarization. Translocator protein (TSPO) is a biomarker of neuroinflammation or microglia activation. Its expression is significantly increased while brain injury and neuroinflammation occur. However, the relationship between TSPO and microglia polarization in CIRI is still not clear. In the present study, the middle cerebral artery occlusion (MCAO) methods in rats were used to simulate CIRI. We found that the expressions of M1 markers (CD86, IL-1β, and TNF-α) and M2 markers (CD206, IL-10, and TGF-β) were significantly increased. Moreover, the injection of TSPO ligand, PK11195, inhibited the increase of M1 polarization markers but promoted the expressions of M2 polarization markers, which significantly ameliorated the neurological damage after MCAO in rats. In vitro studies showed that shRNA-mediated TSPO knock-down promoted M1 polarization but inhibited M2 polarization, accompanied by a significant decrease in cell viability. On the contrary, overexpression of TSPO inhibited M1 polarization, promoted M2 polarization, and significantly improved cell viability. In summary, TSPO plays a neuroprotective role in CIRI by inhibiting M1 polarization and promoting M2 polarization, which suggests that TSPO may have the potential to serve as a therapeutic target for stroke.
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Choudhury ME, Miyanishi K, Takeda H, Tanaka J. Microglia and the Aging Brain: Are Geriatric Microglia Linked to Poor Sleep Quality? Int J Mol Sci 2021; 22:ijms22157824. [PMID: 34360590 PMCID: PMC8345993 DOI: 10.3390/ijms22157824] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/15/2021] [Accepted: 07/20/2021] [Indexed: 12/14/2022] Open
Abstract
Poor sleep quality and disrupted circadian behavior are a normal part of aging and include excessive daytime sleepiness, increased sleep fragmentation, and decreased total sleep time and sleep quality. Although the neuronal decline underlying the cellular mechanism of poor sleep has been extensively investigated, brain function is not fully dependent on neurons. A recent antemortem autographic study and postmortem RNA sequencing and immunohistochemical studies on aged human brain have investigated the relationship between sleep fragmentation and activation of the innate immune cells of the brain, microglia. In the process of aging, there are marked reductions in the number of brain microglial cells, and the depletion of microglial cells disrupts circadian rhythmicity of brain tissue. We also showed, in a previous study, that pharmacological suppression of microglial function induced sleep abnormalities. However, the mechanism underlying the contribution of microglial cells to sleep homeostasis is only beginning to be understood. This review revisits the impact of aging on the microglial population and activation, as well as microglial contribution to sleep maintenance and response to sleep loss. Most importantly, this review will answer questions such as whether there is any link between senescent microglia and age-related poor quality sleep and how this exacerbates neurodegenerative disease.
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Affiliation(s)
- Mohammed E. Choudhury
- Department of Molecular and Cellular Physiology, Ehime University Graduate School of Medicine, Shitsukawa, Toon 791-0295, Ehime, Japan
- Correspondence: (M.E.C.); (J.T.)
| | - Kazuya Miyanishi
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba 305-8575, Ibaraki, Japan;
| | - Haruna Takeda
- Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, Aoba, Sendai 980-8575, Miyagi, Japan;
| | - Junya Tanaka
- Department of Molecular and Cellular Physiology, Ehime University Graduate School of Medicine, Shitsukawa, Toon 791-0295, Ehime, Japan
- Correspondence: (M.E.C.); (J.T.)
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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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7
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Vaht M. Variation rs6971 in the Translocator Protein Gene ( TSPO) is Associated with Aggressiveness and Impulsivity but Not with Anxiety in a Population-Representative Sample of Young Adults. The Journal of Genetic Psychology 2021; 182:149-162. [PMID: 33769215 DOI: 10.1080/00221325.2021.1896470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Expression of the 18-kDa translocator protein (TSPO), originally identified as a peripheral benzodiazepine receptor, has been found to be altered in several psychiatric disorders. A common single nucleotide polymorphism (rs6971) in the TSPO gene leads to an amino acid substitution, Ala147Thr, which dramatically alters the affinity with which TSPO binds drug ligands. As cholesterol also binds TSPO in the same transmembrane domain, it is suggested that this substitution may impair the ability of TSPO to bind or import cholesterol, and hence may affect steroid synthesis and hypothalamic-pituitary-adrenal function. The analysis was carried out on older birth cohort (n = 655) of the longitudinal Estonian Children Personality, Behavior and Health Study sample. Anxiety, aggressive behavior, impulsiveness, and history of stressful life events were self-reported in various data collection waves. Psychiatric assessment of lifetime prevalence of anxiety disorders was carried out at 25 years of age by experienced clinical psychologists. TSPO rs6971 was genotyped in all participants. TSPO rs6971 was not associated with self-reported levels of anxiety or lifetime prevalence of anxiety disorders. However, participants homozygous for the minor A allele displayed the highest aggressiveness and dysfunctional impulsivity scores. The positive, adaptive aspect of impulsivity was sensitive to stressful life events, as the AA genotype was associated with functional impulsivity only when the participants had experienced a low number of stressful life events during childhood. TSPO rs6971 polymorphism may be related to development of aggressiveness and impulsivity by adulthood, regardless of the participants' gender.
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Affiliation(s)
- Mariliis Vaht
- Institute of Psychology, University of Tartu, Tartu, Estonia.,Institute of Genomics, University of Tartu, Tartu, Estonia
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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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Etxeberria-Rekalde E, Alzola-Aldamizetxebarria S, Flunkert S, Hable I, Daurer M, Neddens J, Hutter-Paier B. Quantification of Huntington's Disease Related Markers in the R6/2 Mouse Model. Front Mol Neurosci 2021; 13:617229. [PMID: 33505246 PMCID: PMC7831778 DOI: 10.3389/fnmol.2020.617229] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 12/10/2020] [Indexed: 12/12/2022] Open
Abstract
Huntington’s disease (HD) is caused by an expansion of CAG triplets in the huntingtin gene, leading to severe neuropathological changes that result in a devasting and lethal phenotype. Neurodegeneration in HD begins in the striatum and spreads to other brain regions such as cortex and hippocampus, causing motor and cognitive dysfunctions. To understand the signaling pathways involved in HD, animal models that mimic the human pathology are used. The R6/2 mouse as model of HD was already shown to present major neuropathological changes in the caudate putamen and other brain regions, but recently established biomarkers in HD patients were yet not analyzed in these mice. We therefore performed an in-depth analysis of R6/2 mice to establish new and highly translational readouts focusing on Ctip2 as biological marker for motor system-related neurons and translocator protein (TSPO) as a promising readout for early neuroinflammation. Our results validate already shown pathologies like mutant huntingtin aggregates, ubiquitination, and brain atrophy, but also provide evidence for decreased tyrosine hydroxylase and Ctip2 levels as indicators of a disturbed motor system, while vesicular acetyl choline transporter levels as marker for the cholinergic system barely change. Additionally, increased astrocytosis and activated microglia were observed by GFAP, Iba1 and TSPO labeling, illustrating, that TSPO is a more sensitive marker for early neuroinflammation compared to GFAP and Iba1. Our results thus demonstrate a high sensitivity and translational value of Ctip2 and TSPO as new marker for the preclinical evaluation of new compounds in the R6/2 mouse model of HD.
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Affiliation(s)
| | | | | | - Isabella Hable
- QPS Austria GmbH, Grambach, Austria.,Department of Health Studies, FH Joanneum University of Applied Sciences, Graz, Austria
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Li F, Hicks JW, Yu L, Desjardin L, Morrison L, Hadway J, Lee TY. Plasma radio-metabolite analysis of PET tracers for dynamic PET imaging: TLC and autoradiography. EJNMMI Res 2020; 10:141. [PMID: 33226509 PMCID: PMC7683627 DOI: 10.1186/s13550-020-00705-2] [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: 06/12/2020] [Accepted: 09/18/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In molecular imaging with dynamic PET, the binding and dissociation of a targeted tracer is characterized by kinetics modeling which requires the arterial concentration of the tracer to be measured accurately. Once in the body the radiolabeled parent tracer may be subjected to hydrolysis, demethylation/dealkylation and other biochemical processes, resulting in the production and accumulation of different metabolites in blood which can be labeled with the same PET radionuclide as the parent. Since these radio-metabolites cannot be distinguished by PET scanning from the parent tracer, their contribution to the arterial concentration curve has to be removed for the accurate estimation of kinetic parameters from kinetic analysis of dynamic PET. High-performance liquid chromatography has been used to separate and measure radio-metabolites in blood plasma; however, the method is labor intensive and remains a challenge to implement for each individual patient. The purpose of this study is to develop an alternate technique based on thin layer chromatography (TLC) and a sensitive commercial autoradiography system (Beaver, Ai4R, Nantes, France) to measure radio-metabolites in blood plasma of two targeted tracers-[18F]FAZA and [18F]FEPPA, for imaging hypoxia and inflammation, respectively. RESULTS Radioactivity as low as 17 Bq in 2 µL of pig's plasma can be detected on the TLC plate using autoradiography. Peaks corresponding to the parent tracer and radio-metabolites could be distinguished in the line profile through each sample (n = 8) in the autoradiographic image. Significant intersubject and intra-subject variability in radio-metabolites production could be observed with both tracers. For [18F]FEPPA, 50% of plasma activity was from radio-metabolites as early as 5-min post injection, while for [18F]FAZA, significant metabolites did not appear until 50-min post. Simulation study investigating the effect of radio-metabolite in the estimation of kinetic parameters indicated that 32-400% parameter error can result without radio-metabolites correction. CONCLUSION TLC coupled with autoradiography is a good alternative to high-performance liquid chromatography for radio-metabolite correction. The advantages of requiring only small blood samples (~ 100 μL) and of analyzing multiple samples simultaneously, make the method suitable for individual dynamic PET studies.
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Affiliation(s)
- Fiona Li
- Department of Medical Biophysics, The University of Western University, 1151 Richmond Street North, London, ON, N6A 3K7, Canada.,Lawson Health Research Institute, Grosvenor Campus, 268 Grosvenor Street, London, ON, N6A 4V2, Canada.,Robarts Research Institute, London, ON, Canada
| | - Justin W Hicks
- Department of Medical Biophysics, The University of Western University, 1151 Richmond Street North, London, ON, N6A 3K7, Canada.,Lawson Health Research Institute, Grosvenor Campus, 268 Grosvenor Street, London, ON, N6A 4V2, Canada
| | - Lihai Yu
- Lawson Health Research Institute, Grosvenor Campus, 268 Grosvenor Street, London, ON, N6A 4V2, Canada
| | - Lise Desjardin
- Lawson Health Research Institute, Grosvenor Campus, 268 Grosvenor Street, London, ON, N6A 4V2, Canada
| | - Laura Morrison
- Lawson Health Research Institute, Grosvenor Campus, 268 Grosvenor Street, London, ON, N6A 4V2, Canada
| | - Jennifer Hadway
- Lawson Health Research Institute, Grosvenor Campus, 268 Grosvenor Street, London, ON, N6A 4V2, Canada.,Robarts Research Institute, London, ON, Canada
| | - Ting-Yim Lee
- Department of Medical Biophysics, The University of Western University, 1151 Richmond Street North, London, ON, N6A 3K7, Canada. .,Lawson Health Research Institute, Grosvenor Campus, 268 Grosvenor Street, London, ON, N6A 4V2, Canada. .,Robarts Research Institute, London, ON, Canada.
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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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12
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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: 42] [Impact Index Per Article: 10.5] [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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13
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Da Pozzo E, Tremolanti C, Costa B, Giacomelli C, Milenkovic VM, Bader S, Wetzel CH, Rupprecht R, Taliani S, Da Settimo F, Martini C. Microglial Pro-Inflammatory and Anti-Inflammatory Phenotypes Are Modulated by Translocator Protein Activation. Int J Mol Sci 2019; 20:ijms20184467. [PMID: 31510070 PMCID: PMC6770267 DOI: 10.3390/ijms20184467] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 09/06/2019] [Accepted: 09/09/2019] [Indexed: 12/13/2022] Open
Abstract
A key role of the mitochondrial Translocator Protein 18 KDa (TSPO) in neuroinflammation has been recently proposed. However, little is known about TSPO-activated pathways underlying the modulation of reactive microglia. In the present work, the TSPO activation was explored in an in vitro human primary microglia model (immortalized C20 cells) under inflammatory stimulus. Two different approaches were used with the aim to (i) pharmacologically amplify or (ii) silence, by the lentiviral short hairpin RNA, the TSPO physiological function. In the TSPO pharmacological stimulation model, the synthetic steroidogenic selective ligand XBD-173 attenuated the activation of microglia. Indeed, it reduces and increases the release of pro-inflammatory and anti-inflammatory cytokines, respectively. Such ligand-induced effects were abolished when C20 cells were treated with the steroidogenesis inhibitor aminoglutethimide. This suggests a role for neurosteroids in modulating the interleukin production. The highly steroidogenic ligand XBD-173 attenuated the neuroinflammatory response more effectively than the poorly steroidogenic ones, which suggests that the observed modulation on the cytokine release may be influenced by the levels of produced neurosteroids. In the TSPO silencing model, the reduction of TSPO caused a more inflamed phenotype with respect to scrambled cells. Similarly, during the inflammatory response, the TSPO silencing increased and reduced the release of pro-inflammatory and anti-inflammatory cytokines, respectively. In conclusion, the obtained results are in favor of a homeostatic role for TSPO in the context of dynamic balance between anti-inflammatory and pro-inflammatory mediators in the human microglia-mediated inflammatory response. Interestingly, our preliminary results propose that the TSPO expression could be stimulated by NF-κB during activation of the inflammatory response.
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Affiliation(s)
- Eleonora Da Pozzo
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy; (E.D.P.); (C.T.); (C.G.); (S.T.); (F.D.S.); (C.M.)
| | - Chiara Tremolanti
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy; (E.D.P.); (C.T.); (C.G.); (S.T.); (F.D.S.); (C.M.)
| | - Barbara Costa
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy; (E.D.P.); (C.T.); (C.G.); (S.T.); (F.D.S.); (C.M.)
- Correspondence:
| | - Chiara Giacomelli
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy; (E.D.P.); (C.T.); (C.G.); (S.T.); (F.D.S.); (C.M.)
| | - Vladimir M. Milenkovic
- Department of Psychiatry and Psychotherapy, Molecular Neurosciences, University of Regensburg, 93059 Regensburg, Germany; (V.M.M.); (S.B.); (C.H.W.); (R.R.)
| | - Stefanie Bader
- Department of Psychiatry and Psychotherapy, Molecular Neurosciences, University of Regensburg, 93059 Regensburg, Germany; (V.M.M.); (S.B.); (C.H.W.); (R.R.)
| | - Christian H. Wetzel
- Department of Psychiatry and Psychotherapy, Molecular Neurosciences, University of Regensburg, 93059 Regensburg, Germany; (V.M.M.); (S.B.); (C.H.W.); (R.R.)
| | - Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, Molecular Neurosciences, University of Regensburg, 93059 Regensburg, Germany; (V.M.M.); (S.B.); (C.H.W.); (R.R.)
| | - Sabrina Taliani
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy; (E.D.P.); (C.T.); (C.G.); (S.T.); (F.D.S.); (C.M.)
| | - Federico Da Settimo
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy; (E.D.P.); (C.T.); (C.G.); (S.T.); (F.D.S.); (C.M.)
| | - Claudia Martini
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy; (E.D.P.); (C.T.); (C.G.); (S.T.); (F.D.S.); (C.M.)
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14
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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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15
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Sex-Dependent Effects of Perinatal Inflammation on the Brain: Implication for Neuro-Psychiatric Disorders. Int J Mol Sci 2019; 20:ijms20092270. [PMID: 31071949 PMCID: PMC6539135 DOI: 10.3390/ijms20092270] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 05/03/2019] [Accepted: 05/06/2019] [Indexed: 12/12/2022] Open
Abstract
Individuals born preterm have higher rates of neurodevelopmental disorders such as schizophrenia, autistic spectrum, and attention deficit/hyperactivity disorders. These conditions are often sexually dimorphic and with different developmental trajectories. The etiology is likely multifactorial, however, infections both during pregnancy and in childhood have emerged as important risk factors. The association between sex- and age-dependent vulnerability to neuropsychiatric disorders has been suggested to relate to immune activation in the brain, including complex interactions between sex hormones, brain transcriptome, activation of glia cells, and cytokine production. Here, we will review sex-dependent effects on brain development, including glia cells, both under normal physiological conditions and following perinatal inflammation. Emphasis will be given to sex-dependent effects on brain regions which play a role in neuropsychiatric disorders and inflammatory reactions that may underlie early-life programming of neurobehavioral disturbances later in life.
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16
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Guignet M, Lein PJ. Neuroinflammation in organophosphate-induced neurotoxicity. ROLE OF INFLAMMATION IN ENVIRONMENTAL NEUROTOXICITY 2019. [DOI: 10.1016/bs.ant.2018.10.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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17
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Simmons DA, James ML, Belichenko NP, Semaan S, Condon C, Kuan J, Shuhendler AJ, Miao Z, Chin FT, Longo FM. TSPO-PET imaging using [18F]PBR06 is a potential translatable biomarker for treatment response in Huntington's disease: preclinical evidence with the p75NTR ligand LM11A-31. Hum Mol Genet 2018; 27:2893-2912. [PMID: 29860333 PMCID: PMC6077813 DOI: 10.1093/hmg/ddy202] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/04/2018] [Accepted: 05/21/2018] [Indexed: 12/11/2022] Open
Abstract
Huntington's disease (HD) is an inherited neurodegenerative disorder that has no cure. HD therapeutic development would benefit from a non-invasive translatable biomarker to track disease progression and treatment response. A potential biomarker is using positron emission tomography (PET) imaging with a translocator protein 18 kDa (TSPO) radiotracer to detect microglial activation, a key contributor to HD pathogenesis. The ability of TSPO-PET to identify microglial activation in HD mouse models, essential for a translatable biomarker, or therapeutic efficacy in HD patients or mice is unknown. Thus, this study assessed the feasibility of utilizing PET imaging with the TSPO tracer, [18F]PBR06, to detect activated microglia in two HD mouse models and to monitor response to treatment with LM11A-31, a p75NTR ligand known to reduce neuroinflammation in HD mice. [18F]PBR06-PET detected microglial activation in striatum, cortex and hippocampus of vehicle-treated R6/2 mice at a late disease stage and, notably, also in early and mid-stage symptomatic BACHD mice. After oral administration of LM11A-31 to R6/2 and BACHD mice, [18F]PBR06-PET discerned the reductive effects of LM11A-31 on neuroinflammation in both HD mouse models. [18F]PBR06-PET signal had a spatial distribution similar to ex vivo brain autoradiography and correlated with microglial activation markers: increased IBA-1 and TSPO immunostaining/blotting and striatal levels of cytokines IL-6 and TNFα. These results suggest that [18F]PBR06-PET is a useful surrogate marker of therapeutic efficacy in HD mice with high potential as a translatable biomarker for preclinical and clinical HD trials.
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Affiliation(s)
- Danielle A Simmons
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Michelle L James
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA
| | - Nadia P Belichenko
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Sarah Semaan
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Christina Condon
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Jason Kuan
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Adam J Shuhendler
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA
| | - Zheng Miao
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA
| | - Frederick T Chin
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA
| | - Frank M Longo
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
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18
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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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19
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Kupa LDVK, Drewes CC, Barioni ED, Neves CL, Sampaio SC, Farsky SHP. Role of Translocator 18 KDa Ligands in the Activation of Leukotriene B4 Activated G-Protein Coupled Receptor and Toll Like Receptor-4 Pathways in Neutrophils. Front Pharmacol 2017; 8:766. [PMID: 29163156 PMCID: PMC5664262 DOI: 10.3389/fphar.2017.00766] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 10/11/2017] [Indexed: 12/13/2022] Open
Abstract
TSPO (Translocator 18 KDa; tryptophan-rich sensory protein oxygen sensor) is a constitutive outer mitochondrial membrane protein overexpressed in inflammatory cells during local or systemic processes. Despite its expression is characterized, role of TSPO in inflammation remains elusive. For this study, we investigated the role of TSPO ligands on neutrophil functions elicited by two different inflammatory pathways. Peritoneal neutrophils were isolated from male Balb-C mice, treated with TSPO ligand diazepam, Ro5-4864 or PK11195 (1,100 or 1000 nM; 2 h) and further stimulated with lipopolysaccharide from Escherichia coli (LPS), a binding for Toll-Like Receptor-4 (TLR4), or leukotriene B4 (LTB4), a G-protein coupled receptor (GPCR) ligand. LPS treatment did not lead to overexpression of TSPO on neutrophils, and pre-treatment with any TSPO ligand did not alter cytokine expression, adhesion molecule expression, or the production of reactive oxygen and nitrogen species caused by LPS stimulation. Conversely, all TSPO ligands impaired LTB4’s actions, as visualized by reductions in L-selectin shedding, β2 integrin overexpression, neutrophil chemotaxis, and actin filament assembly. TSPO ligands showed distinct intracellular effects on LTB4-induced neutrophil locomotion, with diazepam enhancing cofilin but not modifying Arp2/3 expression, and Ro5-4864 and PK11195 reducing both cofilin and Arp2/3 expression. Taken together, our data exclude a direct role of TSPO ligands in TLR4-elicited pathways, and indicate that TSPO activation inhibits GPCR inflammatory pathways in neutrophils, with a relevant role in neutrophil influx into inflammatory sites.
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Affiliation(s)
- Léonard de Vinci Kanda Kupa
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Carine C Drewes
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Eric D Barioni
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Camila L Neves
- Laboratory of Pathophysiology, Institute Butantan, São Paulo, Brazil
| | | | - Sandra H P Farsky
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
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20
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Frago LM, Canelles S, Freire-Regatillo A, Argente-Arizón P, Barrios V, Argente J, Garcia-Segura LM, Chowen JA. Estradiol Uses Different Mechanisms in Astrocytes from the Hippocampus of Male and Female Rats to Protect against Damage Induced by Palmitic Acid. Front Mol Neurosci 2017; 10:330. [PMID: 29114202 PMCID: PMC5660686 DOI: 10.3389/fnmol.2017.00330] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 09/29/2017] [Indexed: 01/22/2023] Open
Abstract
An excess of saturated fatty acids can be toxic for tissues, including the brain, and this has been associated with the progression of neurodegenerative diseases. Since palmitic acid (PA) is a free fatty acid that is abundant in the diet and circulation and can be harmful, we have investigated the effects of this fatty acid on lipotoxicity in hippocampal astrocytes and the mechanism involved. Moreover, as males and females have different susceptibilities to some neurodegenerative diseases, we accessed the responses of astrocytes from both sexes, as well as the possible involvement of estrogens in the protection against fatty acid toxicity. PA increased endoplasmic reticulum stress leading to cell death in astrocytes from both males and females. Estradiol (E2) increased the levels of protective factors, such as Hsp70 and the anti-inflammatory cytokine interleukin-10, in astrocytes from both sexes. In male astrocytes, E2 decreased pJNK, TNFα, and caspase-3 activation. In contrast, in female astrocytes E2 did not affect the activation of JNK or TNFα levels, but decreased apoptotic cell death. Hence, although E2 exerted protective effects against the detrimental effects of PA, the mechanisms involved appear to be different between male and female astrocytes. This sexually dimorphic difference in the protective mechanisms induced by E2 could be involved in the different susceptibilities of males and females to some neurodegenerative processes.
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Affiliation(s)
- Laura M Frago
- Departamento de Pediatría, Universidad Autónoma de Madrid, Madrid, Spain.,Departamento de Endocrinología, Hospital Infantil Universitario Niño Jesús, Madrid, Spain.,Instituto de Investigación Sanitaria Princesa, Madrid, Spain.,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain
| | - Sandra Canelles
- Departamento de Endocrinología, Hospital Infantil Universitario Niño Jesús, Madrid, Spain.,Instituto de Investigación Sanitaria Princesa, Madrid, Spain.,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain
| | - Alejandra Freire-Regatillo
- Departamento de Pediatría, Universidad Autónoma de Madrid, Madrid, Spain.,Departamento de Endocrinología, Hospital Infantil Universitario Niño Jesús, Madrid, Spain.,Instituto de Investigación Sanitaria Princesa, Madrid, Spain.,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain
| | - Pilar Argente-Arizón
- Departamento de Pediatría, Universidad Autónoma de Madrid, Madrid, Spain.,Departamento de Endocrinología, Hospital Infantil Universitario Niño Jesús, Madrid, Spain.,Instituto de Investigación Sanitaria Princesa, Madrid, Spain.,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain
| | - Vicente Barrios
- Departamento de Endocrinología, Hospital Infantil Universitario Niño Jesús, Madrid, Spain.,Instituto de Investigación Sanitaria Princesa, Madrid, Spain.,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain
| | - Jesús Argente
- Departamento de Pediatría, Universidad Autónoma de Madrid, Madrid, Spain.,Departamento de Endocrinología, Hospital Infantil Universitario Niño Jesús, Madrid, Spain.,Instituto de Investigación Sanitaria Princesa, Madrid, Spain.,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain.,IMDEA Food Institute, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Luis M Garcia-Segura
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.,CIBER de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | - Julie A Chowen
- Departamento de Endocrinología, Hospital Infantil Universitario Niño Jesús, Madrid, Spain.,Instituto de Investigación Sanitaria Princesa, Madrid, Spain.,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain
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21
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Owen DR, Narayan N, Wells L, Healy L, Smyth E, Rabiner EA, Galloway D, Williams JB, Lehr J, Mandhair H, Peferoen LA, Taylor PC, Amor S, Antel JP, Matthews PM, Moore CS. Pro-inflammatory activation of primary microglia and macrophages increases 18 kDa translocator protein expression in rodents but not humans. J Cereb Blood Flow Metab 2017; 37:2679-2690. [PMID: 28530125 PMCID: PMC5536262 DOI: 10.1177/0271678x17710182] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The 18kDa Translocator Protein (TSPO) is the most commonly used tissue-specific marker of inflammation in positron emission tomography (PET) studies. It is expressed in myeloid cells such as microglia and macrophages, and in rodent myeloid cells expression increases with cellular activation. We assessed the effect of myeloid cell activation on TSPO gene expression in both primary human and rodent microglia and macrophages in vitro, and also measured TSPO radioligand binding with 3H-PBR28 in primary human macrophages. As observed previously, we found that TSPO expression increases (∼9-fold) in rodent-derived macrophages and microglia upon pro-inflammatory stimulation. However, TSPO expression does not increase with classical pro-inflammatory activation in primary human microglia (fold change 0.85 [95% CI 0.58-1.12], p = 0.47). In contrast, pro-inflammatory activation of human monocyte-derived macrophages is associated with a reduction of both TSPO gene expression (fold change 0.60 [95% CI 0.45-0.74], p = 0.02) and TSPO binding site abundance (fold change 0.61 [95% CI 0.49-0.73], p < 0.0001). These findings have important implications for understanding the biology of TSPO in activated macrophages and microglia in humans. They are also clinically relevant for the interpretation of PET studies using TSPO targeting radioligands, as they suggest changes in TSPO expression may reflect microglial and macrophage density rather than activation phenotype.
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Affiliation(s)
- David R Owen
- 1 Division of Brain Sciences, Department of Medicine Hammersmith Hospital, Imperial College London, London, UK
| | - Nehal Narayan
- 2 Nuffield Department of Orthopaedics, Rheumatology & Musculoskeletal Sciences, Botnar Research Centre, University of Oxford, Oxford, UK
| | - Lisa Wells
- 3 Imanova Centre for Imaging Science, Hammersmith Hospital, London, UK
| | - Luke Healy
- 4 Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Erica Smyth
- 3 Imanova Centre for Imaging Science, Hammersmith Hospital, London, UK
| | - Eugenii A Rabiner
- 3 Imanova Centre for Imaging Science, Hammersmith Hospital, London, UK.,5 Centre for Neuroimaging Sciences, King's College, London, UK
| | - Dylan Galloway
- 6 Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland
| | - John B Williams
- 6 Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland
| | - Joshua Lehr
- 6 Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland
| | - Harpreet Mandhair
- 2 Nuffield Department of Orthopaedics, Rheumatology & Musculoskeletal Sciences, Botnar Research Centre, University of Oxford, Oxford, UK
| | - Laura An Peferoen
- 7 Pathology Department, VU Medical Centre, VU University of Amsterdam, The Netherlands
| | - Peter C Taylor
- 2 Nuffield Department of Orthopaedics, Rheumatology & Musculoskeletal Sciences, Botnar Research Centre, University of Oxford, Oxford, UK
| | - Sandra Amor
- 7 Pathology Department, VU Medical Centre, VU University of Amsterdam, The Netherlands.,8 Neuroimmunology Unit, Blizard Institute, Barts and the London School of medicine & Dentistry Queen Mary University of London, UK
| | - Jack P Antel
- 4 Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Paul M Matthews
- 1 Division of Brain Sciences, Department of Medicine Hammersmith Hospital, Imperial College London, London, UK.,9 UK Dementia Research Institute, Imperial College London, London, UK
| | - Craig S Moore
- 6 Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland
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22
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Thelin EP, Tajsic T, Zeiler FA, Menon DK, Hutchinson PJA, Carpenter KLH, Morganti-Kossmann MC, Helmy A. Monitoring the Neuroinflammatory Response Following Acute Brain Injury. Front Neurol 2017; 8:351. [PMID: 28775710 PMCID: PMC5517395 DOI: 10.3389/fneur.2017.00351] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 07/04/2017] [Indexed: 12/11/2022] Open
Abstract
Traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) are major contributors to morbidity and mortality. Following the initial insult, patients may deteriorate due to secondary brain damage. The underlying molecular and cellular cascades incorporate components of the innate immune system. There are different approaches to assess and monitor cerebral inflammation in the neuro intensive care unit. The aim of this narrative review is to describe techniques to monitor inflammatory activity in patients with TBI and SAH in the acute setting. The analysis of pro- and anti-inflammatory cytokines in compartments of the central nervous system (CNS), including the cerebrospinal fluid and the extracellular fluid, represent the most common approaches to monitor surrogate markers of cerebral inflammatory activity. Each of these compartments has a distinct biology that reflects local processes and the cross-talk between systemic and CNS inflammation. Cytokines have been correlated to outcomes as well as ongoing, secondary injury progression. Alongside the dynamic, focal assay of humoral mediators, imaging, through positron emission tomography, can provide a global in vivo measurement of inflammatory cell activity, which reveals long-lasting processes following the initial injury. Compared to the innate immune system activated acutely after brain injury, the adaptive immune system is likely to play a greater role in the chronic phase as evidenced by T-cell-mediated autoreactivity toward brain-specific proteins. The most difficult aspect of assessing neuroinflammation is to determine whether the processes monitored are harmful or beneficial to the brain as accumulating data indicate a dual role for these inflammatory cascades following injury. In summary, the inflammatory component of the complex injury cascade following brain injury may be monitored using different modalities. Using a multimodal monitoring approach can potentially aid in the development of therapeutics targeting different aspects of the inflammatory cascade and improve the outcome following TBI and SAH.
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Affiliation(s)
- Eric Peter Thelin
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Tamara Tajsic
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Frederick Adam Zeiler
- Division of Anaesthesia, Department of Medicine, University of Cambridge, Cambridge, United Kingdom.,Rady Faculty of Health Sciences, Department of Surgery, University of Manitoba, Winnipeg, MB, Canada.,Clinician Investigator Program, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - David K Menon
- Division of Anaesthesia, Department of Medicine, University of Cambridge, Cambridge, United Kingdom.,Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Peter J A Hutchinson
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.,Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Keri L H Carpenter
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.,Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Maria Cristina Morganti-Kossmann
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia.,Department of Child Health, Barrow Neurological Institute at Phoenix Children's Hospital, University of Arizona College of Medicine, Phoenix, Phoenix, AZ, United States
| | - Adel Helmy
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
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Dupont AC, Largeau B, Santiago Ribeiro MJ, Guilloteau D, Tronel C, Arlicot N. Translocator Protein-18 kDa (TSPO) Positron Emission Tomography (PET) Imaging and Its Clinical Impact in Neurodegenerative Diseases. Int J Mol Sci 2017; 18:ijms18040785. [PMID: 28387722 PMCID: PMC5412369 DOI: 10.3390/ijms18040785] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/31/2017] [Accepted: 04/04/2017] [Indexed: 02/06/2023] Open
Abstract
In vivo exploration of activated microglia in neurodegenerative diseases is achievable by Positron Emission Tomography (PET) imaging, using dedicated radiopharmaceuticals targeting the translocator protein-18 kDa (TSPO). In this review, we emphasized the major advances made over the last 20 years, thanks to TSPO PET imaging, to define the pathophysiological implication of microglia activation and neuroinflammation in neurodegenerative diseases, including Parkinson’s disease, Huntington’s disease, dementia, amyotrophic lateral sclerosis, multiple sclerosis, and also in psychiatric disorders. The extent and upregulation of TSPO as a molecular biomarker of activated microglia in the human brain is now widely documented in these pathologies, but its significance, and especially its protective or deleterious action regarding the disease’s stage, remains under debate. Thus, we exposed new and plausible suggestions to enhance the contribution of TSPO PET imaging for biomedical research by exploring microglia’s role and interactions with other cells in brain parenchyma. Multiplex approaches, associating TSPO PET radiopharmaceuticals with other biomarkers (PET imaging of cellular metabolism, neurotransmission or abnormal protein aggregates, but also other imaging modalities, and peripheral cytokine levels measurement and/or metabolomics analysis) was considered. Finally, the actual clinical impact of TSPO PET imaging as a routine biomarker of neuroinflammation was put into perspective regarding the current development of diagnostic and therapeutic strategies for neurodegenerative diseases.
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Affiliation(s)
- Anne-Claire Dupont
- CHRU Tours, 2 Boulevard Tonnellé, 37044 Tours, France.
- Institut National de la Santé et de la Recherche Médicale U930, 10 Boulevard Tonnellé, 37032 Tours, France.
| | | | - Maria Joao Santiago Ribeiro
- CHRU Tours, 2 Boulevard Tonnellé, 37044 Tours, France.
- Institut National de la Santé et de la Recherche Médicale U930, 10 Boulevard Tonnellé, 37032 Tours, France.
| | - Denis Guilloteau
- CHRU Tours, 2 Boulevard Tonnellé, 37044 Tours, France.
- Institut National de la Santé et de la Recherche Médicale U930, 10 Boulevard Tonnellé, 37032 Tours, France.
| | - Claire Tronel
- Institut National de la Santé et de la Recherche Médicale U930, 10 Boulevard Tonnellé, 37032 Tours, France.
| | - Nicolas Arlicot
- CHRU Tours, 2 Boulevard Tonnellé, 37044 Tours, France.
- Institut National de la Santé et de la Recherche Médicale U930, 10 Boulevard Tonnellé, 37032 Tours, France.
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24
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Belloli S, Pannese M, Buonsanti C, Maiorino C, Di Grigoli G, Carpinelli A, Monterisi C, Moresco RM, Panina-Bordignon P. Early upregulation of 18-kDa translocator protein in response to acute neurodegenerative damage in TREM2-deficient mice. Neurobiol Aging 2017; 53:159-168. [PMID: 28189343 DOI: 10.1016/j.neurobiolaging.2017.01.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 11/21/2016] [Accepted: 01/06/2017] [Indexed: 10/20/2022]
Abstract
Mutations in the TREM2 gene confer risk for Alzheimer's disease and susceptibility for Parkinson's disease (PD). We evaluated the effect of TREM2 deletion in a 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model, measuring neurodegeneration and microglia activation using a combined in vivo imaging and postmortem molecular approach. In wild-type mice, MPTP administration induced a progressive decrease of [11C]FECIT uptake, culminating at day 7. Neuronal loss was accompanied by an increase of TREM2, IL-1β, and translocator protein (TSPO) transcript levels, [11C]PK11195 binding and GFAP staining (from day 2), and an early and transient increase of TNF-α, Galectin-3, and Iba-1 (from day 1). In TREM2 null (TREM2-/-) mice, MPTP similarly affected neuron viability and microglial cells, as shown by the lower level of Iba-1 staining in basal condition, and reduced increment of Iba-1, TNF-α, and IL-1β in response to MPTP. Likely to compensate for TREM2 absence, TREM2-/- mice showed an earlier increment of [11C]PK11195 binding and a significant increase of IL-4. Taken together, our data demonstrate a central role of TREM2 in the regulation of microglia response to acute neurotoxic insults and suggest a potential modulatory role of TSPO in response to immune system deficit.
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Affiliation(s)
- Sara Belloli
- Institute of Bioimages and Molecular Physiology, National Research Council, Segrate, MI, Italy; Milan Center for Neuroscience (NeuroMi), Milan, Italy; Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Maria Pannese
- Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Cecilia Buonsanti
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Chiara Maiorino
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Giuseppe Di Grigoli
- Institute of Bioimages and Molecular Physiology, National Research Council, Segrate, MI, Italy; Milan Center for Neuroscience (NeuroMi), Milan, Italy
| | - Assunta Carpinelli
- Institute of Bioimages and Molecular Physiology, National Research Council, Segrate, MI, Italy
| | - Cristina Monterisi
- Department of Medicine and Surgery, University of Milan Bicocca, Monza, Italy
| | - Rosa Maria Moresco
- Milan Center for Neuroscience (NeuroMi), Milan, Italy; Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy; Department of Medicine and Surgery, University of Milan Bicocca, Monza, Italy.
| | - Paola Panina-Bordignon
- Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
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25
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Lee JW, Nam H, Yu SW. Systematic Analysis of Translocator Protein 18 kDa (TSPO) Ligands on Toll-like Receptors-mediated Pro-inflammatory Responses in Microglia and Astrocytes. Exp Neurobiol 2016; 25:262-268. [PMID: 27790060 PMCID: PMC5081472 DOI: 10.5607/en.2016.25.5.262] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 08/24/2016] [Accepted: 08/25/2016] [Indexed: 02/06/2023] Open
Abstract
Translocator protein 18 kDa (TSPO) is a mitochondrial protein highly expressed on reactive microglia and astrocytes, and is considered as a biomarker for neurodegeneration and brain damage, especially neuroinflammation. Toll-like receptors (TLRs) are closely related with inflammatory responses of microglia and astrocytes and these signaling pathways regulate neuroinflammation. Previous reports have identified the anti-inflammatory effects of TSPO ligands, however study of their effects in relation to the TLR signaling was limited. Here, we investigated the effects of five representative TSPO ligands on microglia and astrocytes following activation by various TLR ligands. Our results show that TSPO ligands reduce the pro-inflammatory response elicited by the TLR ligands with more profound effects on microglia than astrocytes.
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Affiliation(s)
- Ji-Won Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Hyeri Nam
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Seong-Woon Yu
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea.; Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
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26
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Flannery BM, Bruun DA, Rowland DJ, Banks CN, Austin AT, Kukis DL, Li Y, Ford BD, Tancredi DJ, Silverman JL, Cherry SR, Lein PJ. Persistent neuroinflammation and cognitive impairment in a rat model of acute diisopropylfluorophosphate intoxication. J Neuroinflammation 2016; 13:267. [PMID: 27733171 PMCID: PMC5062885 DOI: 10.1186/s12974-016-0744-y] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/06/2016] [Indexed: 12/19/2022] Open
Abstract
Background Acute intoxication with organophosphorus (OP) cholinesterase inhibitors can trigger convulsions that progress to life-threatening status epilepticus. Survivors face long-term morbidity including mild-to-severe decline in memory. It is posited that neuroinflammation plays a key role in the pathogenesis of OP-induced neuropsychiatric deficits. Rigorous testing of this hypothesis requires preclinical models that recapitulate relevant phenotypic outcomes. Here, we describe a rat model of acute intoxication with the OP diisopropylfluorophosphate (DFP) that exhibits persistent neuroinflammation and cognitive impairment. Methods Neuroinflammation, neurodegeneration, and cognitive function were compared in adult male Sprague Dawley rats injected with an acutely toxic dose of DFP vs. vehicle controls at multiple time points up to 36 days post-exposure. Neuroinflammation was quantified using immunohistochemical biomarkers of microglia (ionized calcium-binding adapter molecule 1, IBA1) and activated astrocytes (glial fibrillary acidic protein, GFAP) and positron emission tomography (PET) imaging of [11C]-(R)-PK11195, a ligand for the 18-kDa mitochondrial membrane translocator protein (TSPO). FluoroJade-B staining was used to assess neurodegeneration; Pavlovian conditioning, to assess cognitive function. Results Animals exhibited moderate-to-severe seizures within minutes of DFP injection that continued for up to 6 h post-injection. As indicated by IBA1 and GFAP immunoreactivity and by PET imaging of TSPO, acute DFP intoxication triggered neuroinflammation in the hippocampus and cortex during the first 3 days that peaked at 7 days and persisted to 21 days post-exposure in most animals. Neurodegeneration was detected in multiple brain regions from 1 to 14 days post-exposure. All DFP-intoxicated animals exhibited significant deficits in contextual fear conditioning at 9 and 20 days post-exposure compared to vehicle controls. Whole-brain TSPO labeling positively correlated with seizure severity score, but did not correlate with performance in the contextual fear-conditioning task. Conclusions We describe a preclinical model in which acute DFP intoxication causes seizures, persistent neuroinflammation, neurodegeneration, and memory impairment. The extent of the neuroinflammatory response is influenced by seizure severity. However, the observation that a subset of animals with moderate seizures and minimal TSPO labeling exhibited cognitive deficits comparable to those of animals with severe seizures and significant TSPO labeling suggests that DFP may impair learning and memory circuitry via mechanisms independent of seizures or neuroinflammation.
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Affiliation(s)
- Brenna M Flannery
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, 95616, USA
| | - Donald A Bruun
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, 95616, USA
| | - Douglas J Rowland
- Center for Molecular and Genomic Imaging, University of California-Davis, Davis, CA, 95616, USA
| | - Christopher N Banks
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, 95616, USA.,Current address: Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Sacramento, CA, 95812, USA
| | - Adam T Austin
- Department of Pediatrics, University of California-Davis Medical Center, Sacramento, CA, 95817, USA.,Current address: Navistar, Inc., 2701 Navistar Drive, Lisle, IL, 60532, USA
| | - David L Kukis
- Center for Molecular and Genomic Imaging, University of California-Davis, Davis, CA, 95616, USA
| | - Yonggang Li
- Division of Biomedical Sciences, University of California-Riverside School of Medicine, Riverside, CA, 92521, USA
| | - Byron D Ford
- Division of Biomedical Sciences, University of California-Riverside School of Medicine, Riverside, CA, 92521, USA
| | - Daniel J Tancredi
- Department of Pediatrics, University of California-Davis Medical Center, Sacramento, CA, 95817, USA
| | - Jill L Silverman
- Department of Psychiatry and Behavioral Sciences, University of California-Davis Medical Center, Sacramento, CA, 95817, USA
| | - Simon R Cherry
- Center for Molecular and Genomic Imaging, University of California-Davis, Davis, CA, 95616, USA
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, 95616, USA.
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27
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TSPO PIGA Ligands Promote Neurosteroidogenesis and Human Astrocyte Well-Being. Int J Mol Sci 2016; 17:ijms17071028. [PMID: 27367681 PMCID: PMC4964404 DOI: 10.3390/ijms17071028] [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: 05/11/2016] [Revised: 06/22/2016] [Accepted: 06/23/2016] [Indexed: 01/05/2023] Open
Abstract
The steroidogenic 18 kDa translocator protein (TSPO) is an emerging, attractive therapeutic tool for several pathological conditions of the nervous system. Here, 13 high affinity TSPO ligands belonging to our previously described N,N-dialkyl-2-phenylindol-3-ylglyoxylamide (PIGA) class were evaluated for their potential ability to affect the cellular Oxidative Metabolism Activity/Proliferation index, which is used as a measure of astrocyte well-being. The most active PIGA ligands were also assessed for steroidogenic activity in terms of pregnenolone production, and the values were related to the metabolic index in rat and human models. The results showed a positive correlation between the increase in the Oxidative Metabolism Activity/Proliferation index and the pharmacologically induced stimulation of steroidogenesis. The specific involvement of steroid molecules in mediating the metabolic effects of the PIGA ligands was demonstrated using aminoglutethimide, a specific inhibitor of the first step of steroid biosynthesis. The most promising steroidogenic PIGA ligands were the 2-naphthyl derivatives that showed a long residence time to the target, in agreement with our previous data. In conclusion, TSPO ligand-induced neurosteroidogenesis was involved in astrocyte well-being.
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28
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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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TSPO ligand PK11195 alleviates neuroinflammation and beta-amyloid generation induced by systemic LPS administration. Brain Res Bull 2016; 121:192-200. [DOI: 10.1016/j.brainresbull.2016.02.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 01/26/2016] [Accepted: 02/01/2016] [Indexed: 12/12/2022]
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30
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Porcu P, Barron AM, Frye CA, Walf AA, Yang SY, He XY, Morrow AL, Panzica GC, Melcangi RC. Neurosteroidogenesis Today: Novel Targets for Neuroactive Steroid Synthesis and Action and Their Relevance for Translational Research. J Neuroendocrinol 2016; 28:12351. [PMID: 26681259 PMCID: PMC4769676 DOI: 10.1111/jne.12351] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 12/12/2015] [Accepted: 12/12/2015] [Indexed: 12/19/2022]
Abstract
Neuroactive steroids are endogenous neuromodulators synthesised in the brain that rapidly alter neuronal excitability by binding to membrane receptors, in addition to the regulation of gene expression via intracellular steroid receptors. Neuroactive steroids induce potent anxiolytic, antidepressant, anticonvulsant, sedative, analgesic and amnesic effects, mainly through interaction with the GABAA receptor. They also exert neuroprotective, neurotrophic and antiapoptotic effects in several animal models of neurodegenerative diseases. Neuroactive steroids regulate many physiological functions, such as the stress response, puberty, the ovarian cycle, pregnancy and reward. Their levels are altered in several neuropsychiatric and neurological diseases and both preclinical and clinical studies emphasise a therapeutic potential of neuroactive steroids for these diseases, whereby symptomatology ameliorates upon restoration of neuroactive steroid concentrations. However, direct administration of neuroactive steroids has several challenges, including pharmacokinetics, low bioavailability, addiction potential, safety and tolerability, which limit its therapeutic use. Therefore, modulation of neurosteroidogenesis to restore the altered endogenous neuroactive steroid tone may represent a better therapeutic approach. This review summarises recent approaches that target the neuroactive steroid biosynthetic pathway at different levels aiming to promote neurosteroidogenesis. These include modulation of neurosteroidogenesis through ligands of the translocator protein 18 kDa and the pregnane xenobiotic receptor, as well as targeting of specific neurosteroidogenic enzymes such as 17β-hydroxysteroid dehydrogenase type 10 or P450 side chain cleavage. Enhanced neurosteroidogenesis through these targets may be beneficial not only for neurodegenerative diseases, such as Alzheimer's disease and age-related dementia, but also for neuropsychiatric diseases, including alcohol use disorders.
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Affiliation(s)
- Patrizia Porcu
- Neuroscience Institute, National Research Council of Italy (CNR), Cagliari, Italy
| | - Anna M. Barron
- Molecular Imaging Center, National Institute of Radiological Sciences, Anagawa, Inage-ku, Chiba, Japan
| | - Cheryl Anne Frye
- Institute of Arctic Biology, The University of Alaska–Fairbanks, Fairbanks, AK, USA
- The University at Albany, Albany, NY, USA
| | - Alicia A. Walf
- Institute of Arctic Biology, The University of Alaska–Fairbanks, Fairbanks, AK, USA
- The University at Albany, Albany, NY, USA
- Department of Cognitive Science, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Song-Yu Yang
- Department of Developmental Biochemistry, NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Xue-Ying He
- Department of Developmental Biochemistry, NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - A. Leslie Morrow
- Departments of Psychiatry and Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Gian Carlo Panzica
- Department of Neuroscience, University of Turin, and NICO - Neuroscience Institute Cavalieri Ottolenghi, Orbassano, Italy
| | - Roberto C. Melcangi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
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32
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Arbo BD, Benetti F, Garcia-Segura LM, Ribeiro MF. Therapeutic actions of translocator protein (18 kDa) ligands in experimental models of psychiatric disorders and neurodegenerative diseases. J Steroid Biochem Mol Biol 2015. [PMID: 26200949 DOI: 10.1016/j.jsbmb.2015.07.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Translocator protein (TSPO) is an 18kDa protein located at contact sites between the outer and the inner mitochondrial membrane. Numerous studies have associated TSPO with the translocation of cholesterol across the aqueous mitochondrial intermembrane space and the regulation of steroidogenesis, as well as with the control of some other mitochondrial functions, such as mitochondrial respiration, mitochondrial permeability transition pore opening, apoptosis and cell proliferation. In the brain, changes in TSPO expression occur in several neuropathological conditions including neurodegenerative diseases and psychiatric disorders. Furthermore, TSPO ligands have been shown to promote neuroprotection in animal models of brain pathology. At least in some cases, the mechanisms of neuroprotection are associated with modifications in brain steroidogenesis. In addition, regulation of neuroinflammation seems to be a common mechanism in the neuroprotective actions of TSPO ligands in different animal models of brain pathology.
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Affiliation(s)
- B D Arbo
- Laboratório de Interação Neuro-Humoral, Department of Physiology, ICBS, Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500, CEP 90050-170 Porto Alegre, RS, Brazil; Cajal Institute, CSIC, Avenida Doctor Arce, 37, 28002 Madrid, Spain.
| | - F Benetti
- Laboratório de Neurofisiologia Cognitiva e do Desenvolvimento, Department of Physiology, ICBS, Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500, CEP 90050-170 Porto Alegre, RS, Brazil
| | | | - M F Ribeiro
- Laboratório de Interação Neuro-Humoral, Department of Physiology, ICBS, Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500, CEP 90050-170 Porto Alegre, RS, Brazil
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33
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Targeting the 18-kDa translocator protein: recent perspectives for neuroprotection. Biochem Soc Trans 2015; 43:559-65. [DOI: 10.1042/bst20150028] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Indexed: 12/14/2022]
Abstract
The translocator protein (TSPO, 18 kDa), mainly localized in the outer mitochondrial membrane of steroidogenic tissues, is involved in several cellular functions. TSPO level alterations have been reported in a number of human disorders, particularly in cancer, psychiatric and neurological diseases. In the central nervous system (CNS), TSPO is usually expressed in glial cells, but also in some neuronal cell types. Interestingly, the expression of TSPO on glial cells rises after brain injury and increased TSPO expression is often observed in neurological disorders, gliomas, encephalitis and traumatic injury. Since TSPO is up-regulated in brain diseases, several structurally different classes of ligands targeting TSPO have been described as potential diagnostic or therapeutic agents. Recent researches have reported that TSPO ligands might be valuable in the treatment of brain diseases. This review focuses on currently available TSPO ligands, as useful tools for the treatment of neurodegeneration, neuro-inflammation and neurotrauma.
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34
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Sanchez-Guajardo V, Tentillier N, Romero-Ramos M. The relation between α-synuclein and microglia in Parkinson's disease: Recent developments. Neuroscience 2015; 302:47-58. [PMID: 25684748 DOI: 10.1016/j.neuroscience.2015.02.008] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Revised: 01/13/2015] [Accepted: 02/04/2015] [Indexed: 12/14/2022]
Abstract
Recent research suggests a complex role for microglia not only in Parkinson's disease but in other disorders involving alpha-synuclein aggregation, such as multiple system atrophy. In these neurodegenerative processes, the activation of microglia is a common pathological finding, which disturbs the homeostasis of the neuronal environment otherwise maintained, among others, by microglia. The term activation comprises any deviation from what otherwise is considered normal microglia status, including cellular abundance, morphology or protein expression. The microglial response during disease will sustain survival or otherwise promote cell degeneration. The novel concepts of alpha-synuclein being released and uptaken by neighboring cells, and their importance in disease progression, positions microglia as the main cell that can clear and handle alpha-synuclein efficiently. Microglia's behavior will therefore be a determinant on the disease's progression. For this reason we believe that the better understanding of microglia's response to alpha-synuclein pathological accumulation across brain areas and disease stages is essential to develop novel therapeutic tools for Parkinson's disease and other alpha-synucleinopathies. In this review we will revise the most recent findings and developments with regard to alpha-synuclein and microglia in Parkinson's disease.
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Affiliation(s)
- V Sanchez-Guajardo
- AU IDEAS center NEURODIN, Aarhus University, DK-8000 Aarhus C, Denmark; Neuroimmunology of Degenerative Disease, Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - N Tentillier
- AU IDEAS center NEURODIN, Aarhus University, DK-8000 Aarhus C, Denmark; CNS Disease Modeling Group, Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - M Romero-Ramos
- AU IDEAS center NEURODIN, Aarhus University, DK-8000 Aarhus C, Denmark; CNS Disease Modeling Group, Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark.
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Agusti A, Dziedzic JL, Hernandez-Rabaza V, Guilarte TR, Felipo V. Rats with minimal hepatic encephalopathy due to portacaval shunt show differential increase of translocator protein (18 kDa) binding in different brain areas, which is not affected by chronic MAP-kinase p38 inhibition. Metab Brain Dis 2014; 29:955-63. [PMID: 24307181 PMCID: PMC4087148 DOI: 10.1007/s11011-013-9461-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 11/21/2013] [Indexed: 01/01/2023]
Abstract
Neuroinflammation plays a main role in neurological deficits in rats with minimal hepatic encephalopathy (MHE) due to portacaval shunt (PCS). Treating PCS rats with SB239063, an inhibitor of MAP-kinase-p38, reduces microglial activation and brain inflammatory markers and restores cognitive and motor function. The translocator protein-(18-kDa) (TSPO) is considered a biomarker of neuroinflammation. TSPO is increased in brain of PCS rats and of cirrhotic patients that died in hepatic coma. Rats with MHE show strong microglial activation in cerebellum and milder in other areas when assessed by MHC-II immunohistochemistry. This work aims were assessing: 1) whether binding of TSPO ligands is selectively increased in cerebellum in PCS rats; 2) whether treatment with SB239063 reduces binding of TSPO ligands in PCS rats; 3) which cell type (microglia, astrocytes) increases TSPO expression. Quantitative autoradiography was used to assess TSPO-selective (3)H-(R)-PK11195 binding to different brain areas. TSPO expression increased differentially in PCS rats, reaching mild expression in striatum or thalamus and very high levels in cerebellum. TSPO was expressed in astrocytes and microglia. Treatment with SB239063 did not reduces (3)[H]-PK11195 binding in PCS rats. SB239063 reduces microglial activation and levels of inflammatory markers, but not binding of TSPO ligands. This indicates that SB239063-induced neuroinflammation reduction in PCS rats is not mediated by effects on TSPO. Also, enhanced TSPO expression is not always associated with cognitive or motor deficits. If enhanced TSPO expression plays a role in mechanisms leading to neurological alterations in MHE, SB239063 would interfere these mechanisms at a later step.
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Affiliation(s)
- Ana Agusti
- Laboratory of Neurobiology, Centro Investigación Príncipe Felipe, Eduardo Primo Yufera, 3, 46012, Valencia, Spain
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36
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Chua SW, Kassiou M, Ittner LM. The translocator protein as a drug target in Alzheimer's disease. Expert Rev Neurother 2014; 14:439-48. [PMID: 24625007 DOI: 10.1586/14737175.2014.896201] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The translocator protein (TSPO) recently emerged as a potential drug target in Alzheimer's disease (AD). This has been fuelled mainly by positron emission topography studies that show the upregulation of TSPO in AD, especially in relation to microgliosis and astrogliosis in amyloid-β and tau pathology. Although data as to the exact role of TSPO in AD is still inconclusive, TSPO appears to be involved in neuroinflammatory processes and AD has been shown to involve substantial inflammation. Therefore, further development and investigation of the pharmacological effect of TSPO ligands in AD pathology are warranted.
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Affiliation(s)
- Sook W Chua
- Dementia Research Unit, School of Medical Sciences, Wallace Wurth Building, University of New South Wales, Sydney, NSW 2052, Australia
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37
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Lin R, Angelin A, Da Settimo F, Martini C, Taliani S, Zhu S, Wallace DC. Genetic analysis of dTSPO, an outer mitochondrial membrane protein, reveals its functions in apoptosis, longevity, and Ab42-induced neurodegeneration. Aging Cell 2014; 13:507-18. [PMID: 24977274 PMCID: PMC4076708 DOI: 10.1111/acel.12200] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The outer mitochondrial membrane (OMM) protein, the translocator protein 18 kDa (TSPO), formerly named the peripheral benzodiazepine receptor (PBR), has been proposed to participate in the pathogenesis of neurodegenerative diseases. To clarify the TSPO function, we identified the Drosophila homolog, CG2789/dTSPO, and studied the effects of its inactivation by P-element insertion, RNAi knockdown, and inhibition by ligands (PK11195, Ro5-4864). Inhibition of dTSPO inhibited wing disk apoptosis in response to γ-irradiation or H2O2 exposure, as well as extended male fly lifespan and inhibited Aβ42-induced neurodegeneration in association with decreased caspase activation. Therefore, dTSPO is an essential mediator of apoptosis in Drosophila and plays a central role in controlling longevity and neurodegenerative disease, making it a promising drug target.
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Affiliation(s)
- Ran Lin
- Department of Physiology and Pathophysiology School of Basic Medical Sciences Health Science Center Peking University Beijing 100191China
- Center for Mitochondrial and Epigenomic Medicine Children's Hospital of Philadelphia Research Institute Philadelphia PA 19104USA
| | - Alessia Angelin
- Center for Mitochondrial and Epigenomic Medicine Children's Hospital of Philadelphia Research Institute Philadelphia PA 19104USA
| | | | - Claudia Martini
- Dipartimento di Farmacia Università di Pisa via Bonanno 656126Pisa Italy
| | - Sabrina Taliani
- Dipartimento di Farmacia Università di Pisa via Bonanno 656126Pisa Italy
| | - Shigong Zhu
- Department of Physiology and Pathophysiology School of Basic Medical Sciences Health Science Center Peking University Beijing 100191China
| | - Douglas C. Wallace
- Center for Mitochondrial and Epigenomic Medicine Children's Hospital of Philadelphia Research Institute Philadelphia PA 19104USA
- Department of Pathology and Laboratory Medicine Perelman School of Medicine University of Pennsylvania Philadelphia PA 19104USA
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R K, D M A, C N, S N W, C D. Oxidative imbalance and anxiety disorders. Curr Neuropharmacol 2014; 12:193-204. [PMID: 24669212 PMCID: PMC3964749 DOI: 10.2174/1570159x11666131120223530] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 05/15/2013] [Accepted: 11/02/2013] [Indexed: 01/22/2023] Open
Abstract
The oxidative imbalance appears to have an important role in anxiety development. Studies in both humans and animals have shown a strong correlation between anxiety and oxidative stress. In humans, for example, the increased malondialdehyde levels and discrepancies in antioxidant enzymes in erythrocytes have been observed. In animals, several studies also show that anxiety-like behavior is related to the oxidative imbalance. Moreover, anxiety-like behavior can be caused by pharmacological-induced oxidative stress. Studies using knockout or overexpression of antioxidant enzymes have shown a relationship between anxiety-like behavior and oxidative stress. Related factors of oxidative stress that could influence anxious behavior are revised, including impaired function of different mitochondrial proteins, inflammatory cytokines, and neurotrophic factors. It has been suggested that a therapy specifically focus in reducing reactive species production may have a beneficial effect in reducing anxiety. However, the neurobiological pathways underlying the effect of oxidative stress on anxiety symptoms are not fully comprehended. The challenge now is to identify the oxidative stress mechanisms likely to be involved in the induction of anxiety symptoms. Understanding these pathways could help to clarify the neurobiology of the anxiety disorder and provide tools for new discovery in therapies and preventive strategies.
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Affiliation(s)
- Krolow R
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| | - Arcego D M
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| | - Noschang C
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| | - Weis S N
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| | - Dalmaz C
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
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Marshall SA, McClain JA, Kelso ML, Hopkins DM, Pauly JR, Nixon K. Microglial activation is not equivalent to neuroinflammation in alcohol-induced neurodegeneration: The importance of microglia phenotype. Neurobiol Dis 2013; 54:239-51. [PMID: 23313316 PMCID: PMC3629000 DOI: 10.1016/j.nbd.2012.12.016] [Citation(s) in RCA: 185] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 12/21/2012] [Accepted: 12/28/2012] [Indexed: 12/19/2022] Open
Abstract
Excessive alcohol intake, a defining characteristic of an alcohol use disorder (AUD), results in neurodegeneration in the hippocampus and entorhinal cortex that has been linked to a variety of cognitive deficits. Neuroinflammation is thought to be a factor in alcohol-induced neurodegeneration, and microglia activation is a key but not sole component of an inflammatory response. These experiments investigate the effects of ethanol exposure in a well-accepted model of an AUD on both microglial activation and blood brain barrier disruption (BBB) in order to understand their relationship to classical definitions of inflammation and alcohol-induced neurodegeneration. Following a four-day binge ethanol paradigm, rat hippocampal and entorhinal cortex tissue was examined using three distinct approaches to determine microglia phenotype and BBB disruption: immunohistochemistry, autoradiography, and ELISA. After ethanol exposure, there was an increase in [(3)H]-PK-11195 binding and OX-42 immunoreactivity indicative of microglial activation; however, microglia were not fully activated since both OX-6 and ED-1 immunoreactive microglia were absent. This data was supported by functional evidence as there was no increase in the proinflammatory cytokines IL-6 or TNF-α, but a 26% increase in the anti-inflammatory cytokine, IL-10, and a 38% increase in the growth factor, TGF-β, seven days after exposure. Furthermore, there was no evidence of a disruption of the BBB. These data suggest that the four-day binge model of an AUD, which produces neurodegeneration in corticolimbic regions, does not elicit classical neuroinflammation but instead produces partially activated microglia. Partial activation of microglia following binge ethanol exposure suggest that microglia in this model have beneficial or homeostatic roles rather than directly contributing to neurodegeneration and are a consequence of alcohol-induced-damage instead of the source of damage.
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Affiliation(s)
- S. Alex Marshall
- Department of Pharmaceutical Sciences, The University of Kentucky, Lexington, KY 40536-0596
| | - Justin A. McClain
- Department of Pharmaceutical Sciences, The University of Kentucky, Lexington, KY 40536-0596
| | | | - Deann M. Hopkins
- Department of Pharmaceutical Sciences, The University of Kentucky, Lexington, KY 40536-0596
| | - James R. Pauly
- Department of Pharmaceutical Sciences, The University of Kentucky, Lexington, KY 40536-0596
| | - Kimberly Nixon
- Department of Pharmaceutical Sciences, The University of Kentucky, Lexington, KY 40536-0596
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Jacobs AH, Tavitian B. Noninvasive molecular imaging of neuroinflammation. J Cereb Blood Flow Metab 2012; 32:1393-415. [PMID: 22549622 PMCID: PMC3390799 DOI: 10.1038/jcbfm.2012.53] [Citation(s) in RCA: 188] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 03/05/2012] [Accepted: 03/23/2012] [Indexed: 12/23/2022]
Abstract
Inflammation is a highly dynamic and complex adaptive process to preserve and restore tissue homeostasis. Originally viewed as an immune-privileged organ, the central nervous system (CNS) is now recognized to have a constant interplay with the innate and the adaptive immune systems, where resident microglia and infiltrating immune cells from the periphery have important roles. Common diseases of the CNS, such as stroke, multiple sclerosis (MS), and neurodegeneration, elicit a neuroinflammatory response with the goal to limit the extent of the disease and to support repair and regeneration. However, various disease mechanisms lead to neuroinflammation (NI) contributing to the disease process itself. Molecular imaging is the method of choice to try to decipher key aspects of the dynamic interplay of various inducers, sensors, transducers, and effectors of the orchestrated inflammatory response in vivo in animal models and patients. Here, we review the basic principles of NI with emphasis on microglia and common neurologic disease mechanisms, the molecular targets which are being used and explored for imaging, and molecular imaging of NI in frequent neurologic diseases, such as stroke, MS, neurodegeneration, epilepsy, encephalitis, and gliomas.
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Affiliation(s)
- Andreas H Jacobs
- European Institute for Molecular Imaging (EIMI) at the Westfalian Wilhelms-University of Münster (WWU), Münster, Germany.
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41
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Santos-Galindo M, Acaz-Fonseca E, Bellini MJ, Garcia-Segura LM. Sex differences in the inflammatory response of primary astrocytes to lipopolysaccharide. Biol Sex Differ 2011; 2:7. [PMID: 21745355 PMCID: PMC3143074 DOI: 10.1186/2042-6410-2-7] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 07/11/2011] [Indexed: 01/09/2023] Open
Abstract
Background Numerous neurological and psychiatric disorders show sex differences in incidence, age of onset, symptomatology or outcome. Astrocytes, one of the glial cell types of the brain, show sex differences in number, differentiation and function. Since astrocytes are involved in the response of neural tissue to injury and inflammation, these cells may participate in the generation of sex differences in the response of the brain to pathological insults. To explore this hypothesis, we have examined whether male and female astrocytes show a different response to an inflammatory challenge and whether perinatal testosterone influences this response. Methods Cortical astrocyte cultures were prepared from postnatal day 1 (one day after birth) male or female CD1 mice pups. In addition, cortical astrocyte cultures were also prepared from female pups that were injected at birth with 100 μg of testosterone propionate or vehicle. Cultures were treated for 5 hours with medium containing lipopolysaccharide (LPS) or with control medium. The mRNA levels of IL6, interferon-inducible protein 10 (IP10), TNFα, IL1β, Toll-like receptor 4 (TLR4), steroidogenic acute regulatory protein and translocator protein were assessed by quantitative real-time polymerase chain reaction. Statistical significance was assessed by unpaired t-test or by one-way analysis of variance followed by the Tukey post hoc test. Results The mRNA levels of IL6, TNFα and IL1β after LPS treatment were significantly higher in astrocytes derived from male or androgenized females compared to astrocytes derived from control or vehicle-injected females. In contrast, IP10 mRNA levels after LPS treatment were higher in astrocytes derived from control or vehicle-injected females than in those obtained from males or androgenized females. The different response of male and female astrocytes to LPS was due neither to differences in the basal expression of the inflammatory molecules nor to differences in the expression of the LPS receptor TLR4. In contrast, the different inflammatory response was associated with increased mRNA levels of translocator protein, a key steroidogenic regulator, in female astrocytes that were treated with LPS. Conclusions Male and female cortical astrocytes respond differentially to an inflammatory challenge and this may be predetermined by perinatal testosterone exposure.
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Hamdi Y, Masmoudi-Kouki O, Kaddour H, Belhadj F, Gandolfo P, Vaudry D, Mokni M, Leprince J, Hachem R, Vaudry H, Tonon MC, Amri M. Protective effect of the octadecaneuropeptide on hydrogen peroxide-induced oxidative stress and cell death in cultured rat astrocytes. J Neurochem 2011; 118:416-28. [DOI: 10.1111/j.1471-4159.2011.07315.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Choi J, Ifuku M, Noda M, Guilarte TR. Translocator protein (18 kDa)/peripheral benzodiazepine receptor specific ligands induce microglia functions consistent with an activated state. Glia 2011; 59:219-30. [PMID: 21125642 DOI: 10.1002/glia.21091] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In the brain, translocator protein (18 kDa) (TSPO), previously called peripheral benzodiazepine receptor (PBR), is a glial protein that has been extensively used as a biomarker of brain injury and inflammation. However, the functional role of TSPO in glial cells is not well characterized. In this study, we show that the TSPO-specific ligands R-PK11195 (PK) and Ro5-4864 (Ro) increased microglia proliferation and phagocytosis with no effect on migration. Both ligands increased reactive oxygen species (ROS) production, and this effect may be mediated by NADPH-oxidase. PK and Ro also produced a small but detectable increase in IL-1β release. We also examined the effect of PK and Ro on the expression of proinflammatory genes and cytokine release in lipopolysaccharide (LPS) and adenosine triphosphate (ATP) activated microglia. PK or Ro had no effect on LPS-induced increase of pro-inflammatory genes, but they both decreased the ATP-induced increase of COX-2 gene expression. Ro, but not PK, enhanced the LPS-induced release of IL-1β. However, Ro decreased the ATP-induced release of IL-1β and TNF-α, and PK decreased the ATP-induced release of TNF-α. Exposure to Ro in the presence of LPS increased the number of apoptotic microglia, an effect that could be blocked by PK. These findings show that TSPO ligands modulate cellular functions consistent with microglia activation. Further, when microglia are activated, these ligands may have therapeutic potential by reducing the expression of pro-inflammatory genes and cytokine release. Finally, Ro-like ligands may be involved in the elimination of activated microglia via apoptosis.
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Affiliation(s)
- Judy Choi
- Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
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44
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Rupprecht R, Papadopoulos V, Rammes G, Baghai TC, Fan J, Akula N, Groyer G, Adams D, Schumacher M. Translocator protein (18 kDa) (TSPO) as a therapeutic target for neurological and psychiatric disorders. Nat Rev Drug Discov 2011; 9:971-88. [PMID: 21119734 DOI: 10.1038/nrd3295] [Citation(s) in RCA: 715] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The translocator protein (18 kDa) (TSPO) is localized primarily in the outer mitochondrial membrane of steroid-synthesizing cells, including those in the central and peripheral nervous system. One of its main functions is the transport of the substrate cholesterol into mitochondria, a prerequisite for steroid synthesis. TSPO expression may constitute a biomarker of brain inflammation and reactive gliosis that could be monitored by using TSPO ligands as neuroimaging agents. Moreover, initial clinical trials have indicated that TSPO ligands might be valuable in the treatment of neurological and psychiatric disorders. This Review focuses on the biology and pathophysiology of TSPO and the potential of currently available TSPO ligands for the diagnosis and treatment of neurological and psychiatric disorders.
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Affiliation(s)
- Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians University, Nussbaumstrasse 7, 80336 Munich, Germany.
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Tolosa L, Caraballo-Miralles V, Olmos G, Lladó J. TNF-α potentiates glutamate-induced spinal cord motoneuron death via NF-κB. Mol Cell Neurosci 2010; 46:176-86. [PMID: 20849956 DOI: 10.1016/j.mcn.2010.09.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 08/31/2010] [Accepted: 09/01/2010] [Indexed: 12/14/2022] Open
Abstract
Besides glutamate excitotoxicity, the neuroinflammatory response is emerging as a relevant contributor to motoneuron loss in amyotrophic lateral sclerosis (ALS). In this regard, high levels of circulating proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-α) have been shown both in human patients and in animal models of ALS. The aim of this work was to study the effects of TNF-α on glutamate-induced excitotoxicity in spinal cord motoneurons. In rat spinal cord organotypic cultures chronic glutamate excitotoxicity, induced by the glutamate-uptake inhibitor threohydroxyaspartate (THA), resulted in motoneuron loss that was associated with a neuroinflammatory response. In the presence of TNF-α, THA-induced excitotoxic motoneuron death was potentiated. Co-exposure to TNF-α and THA also resulted in down-regulation of the astroglial glutamate transporter 1 (GLT-1) and in increased extracellular glutamate levels, which were prevented by nuclear factor-kappaB (NF-κB) inhibition. Furthermore, TNF-α and THA also cooperated in the induction of oxidative stress in a mechanism involving the NF-κB signalling pathway as well. The inhibition of this pathway abrogated the exacerbation of glutamate-mediated motoneuron death induced by TNF-α. These data link two important pathogenic mechanisms, excitotoxicity and neuroinflammation, suggested to play a role in ALS and, to our knowledge, this is the first time that TNF-α-induced NF-κB activation has been reported to potentiate glutamate excitotoxicity on motononeurons.
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Affiliation(s)
- Laia Tolosa
- Grup de Neurobiologia Cel·lular, Institut Universitari d'Investigacions en Ciències de la Salut (IUNICS)/Departament de Biologia, Universitat de les Illes Balears, Cra. de Valldemossa km 7.5,E-07122 Palma de Mallorca, Spain
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46
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CCR7 is expressed in astrocytes and upregulated after an inflammatory injury. J Neuroimmunol 2010; 227:87-92. [PMID: 20638137 DOI: 10.1016/j.jneuroim.2010.06.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2010] [Revised: 05/19/2010] [Accepted: 06/21/2010] [Indexed: 11/20/2022]
Abstract
Neurodegenerative or autoimmune diseases are frequently regulated by chemokines and their receptors, controlling both glial activation and immune cell infiltration. CCL19 and CCL21 have been described to mediate crucial functions during CNS pathological states, regulating both immune cell traffic to the CNS and communication between glia and neurons. Here, we describe the expression pattern and cellular sources of CCR7, receptor of CCL19 and CCL21, in the normal mouse brain. Moreover, we found that CCR7 is upregulated in reactive astrocytes upon intracerebral LPS, regulating early glial reactivity through its ligands CCL19 and CCL21. Our results indicate that CCR7 is playing an important role for the intercellular communication during the inflammatory activation in the CNS.
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47
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Yu JT, Lee CH, Yoo KY, Choi JH, Li H, Park OK, Yan B, Hwang IK, Kwon YG, Kim YM, Won MH. Maintenance of anti-inflammatory cytokines and reduction of glial activation in the ischemic hippocampal CA1 region preconditioned with lipopolysaccharide. J Neurol Sci 2010; 296:69-78. [PMID: 20580380 DOI: 10.1016/j.jns.2010.06.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 05/27/2010] [Accepted: 06/02/2010] [Indexed: 12/31/2022]
Abstract
Lipopolysaccharide (LPS) induces a strong immune response, and pretreatment with low dose of LPS suppresses the production of proinflammatory mediators. In the present study, we investigated the effect of LPS preconditioning on the delayed neuronal death in the gerbil hippocampal CA1 region after 5 min of transient cerebral ischemia. LPS preconditioning showed neuroprotective effects against ischemic damage in the hippocampal CA1 region after ischemic insult: about 92% of neurons in the CA1 region survived in the LPS-treated ischemia group. LPS preconditioning maintained anti-inflammatory cytokines, such as interleukin (IL)-4 and IL-13, in pyramidal neurons in the CA1 region after ischemia/reperfusion. In addition, IL-4 and IL-13 protein levels in the CA1 region of the LPS-treated ischemia group were similar to the vehicle-treated sham group. We found that reactive gliosis was markedly attenuated in the CA1 region of the LPS-treated ischemia group compared to the vehicle-treated ischemia group using immunohistochemistry of glial fibrillary acidic protein for astrocytes, and ionized calcium-binding adapter molecule 1 and isolectin B4 for microglia. These results indicate that LPS preconditioning may provide neuroprotection in the ischemic hippocampal CA1 region via maintenance of anti-inflammatory cytokines and suppression of glial activation.
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Affiliation(s)
- Jia Tian Yu
- Department of Anatomy and Neurobiology, and Institute of Neurodegeneration and Neuroregeneration, College of Medicine, Hallym University, Chuncheon 200-702, Republic of Korea
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Azcoitia I, DonCarlos LL, Arevalo MA, Garcia-Segura LM. Therapeutic implications of brain steroidogenesis. Horm Mol Biol Clin Investig 2010; 1:21-6. [PMID: 25961968 DOI: 10.1515/hmbci.2010.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Accepted: 06/16/2009] [Indexed: 12/24/2022]
Abstract
The nervous system is a steroidogenic tissue and several steroids synthesized locally in the brain, such as pregnenolone, progesterone and estradiol, modulate neuronal and glial physiology and are neuroprotective. The brain upregulates steroidogenesis at sites of injury as part of a program triggered by neural tissue to cope with neurodegenerative insults. Pharmacological targets to increase brain steroidogenesis and promote neuroprotection include the molecules that transport cholesterol to the inner mitochondrial membrane, where the first enzyme for steroidogenesis is located. Furthermore, the human gene encoding aromatase, the enzyme that synthesizes estradiol, is under the control of different tissue-specific promoters, and it is therefore conceivable that selective aromatase modulators can be developed that will enhance the expression of the enzyme and the consequent increase in estrogen formation in the brain but not in other tissues.
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Giatti S, Pesaresi M, Cavaletti G, Bianchi R, Carozzi V, Lombardi R, Maschi O, Lauria G, Garcia-Segura L, Caruso D, Melcangi R. Neuroprotective effects of a ligand of translocator protein-18kDa (Ro5-4864) in experimental diabetic neuropathy. Neuroscience 2009; 164:520-9. [DOI: 10.1016/j.neuroscience.2009.08.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 08/03/2009] [Accepted: 08/03/2009] [Indexed: 12/11/2022]
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Papadopoulos V, Lecanu L. Translocator protein (18 kDa) TSPO: an emerging therapeutic target in neurotrauma. Exp Neurol 2009; 219:53-7. [PMID: 19409385 DOI: 10.1016/j.expneurol.2009.04.016] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Accepted: 04/22/2009] [Indexed: 12/11/2022]
Abstract
Traumatic brain injury (TBI) induces physical, cognitive, and psychosocial deficits that affect millions of patients. TBI activates numerous cellular mechanisms and molecular cascades that produce detrimental outcomes, including neuronal death and loss of function. The mitochondrion is one of the major targets of TBI, as seen by increased mitochondrial activity in activated and proliferating microglia (due to high energy requirements and/or calcium overload) as well as increased reactive oxygen species, changes in mitochondrial permeability transition, release of cytochrome c, caspase activation, reduced ATP levels, and cell death in neurons. Translocator protein (TSPO) is an 18-kDa outer mitochondrial membrane protein that interacts with the mitochondria permeability transition pore and binds with high affinity to cholesterol and various classes of drug ligands, including some benzodiazepines such as 4'-chlorodiazepam (Ro5-4864). Although TSPO levels in the brain are low, they are increased after brain injury and inflammation. This finding has led to the proposed use of TSPO expression as a marker of brain injury and repair. TSPO drug ligands have been shown to participate in the control of mitochondrial respiration and function, mitochondrial steroid and neurosteroid formation, as well as apoptosis. This review and commentary will outline our current knowledge of the benefits of targeting TSPO for TBI treatment and the mechanisms underlying the neuroprotective effects of TSPO drug ligands in neurotrauma.
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Affiliation(s)
- Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre and Department of Medicine, McGill University, 1650 Cedar Avenue, Montreal, Quebec, Canada H3G 1A4.
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