1
|
Mikkelsen JD, Aripaka SS, Egilmez CB, Pazarlar BA. Binding of the monoacylglycerol lipase (MAGL) radiotracer [ 3H]T-401 in the rat brain after status epilepticus. Neurochem Int 2024; 175:105717. [PMID: 38447759 DOI: 10.1016/j.neuint.2024.105717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/29/2024] [Accepted: 03/03/2024] [Indexed: 03/08/2024]
Abstract
OBJECTIVES Monoacylglycerol lipase (MAGL) is a cytosolic serine hydrolase considered a potential novel drug target for the treatment of CNS disorders including epilepsy. Here we examined MAGL levels in a rat model of epilepsy. METHODS Autoradiography has been used to validate the binding properties of the MAGL radiotracer, [3H]T-401, in the rat brain, and to explore spatial and temporal changes in binding levels in a model of temporal lobe epilepsy model using unilateral intra-hippocampal injections of kainic acid (KA) in rats. RESULTS Specific and saturable binding of [3H]T-401 was detected in both cortical grey and subcortical white matter. Saturation experiments revealed a KD in the range between 15 nM and 17 nM, and full saturation was achieved at concentrations around 30 nM. The binding could be completely blocked with the cold ligand (Ki 44.2 nM) and at higher affinity (Ki 1.27 nM) with another structurally different MAGL inhibitor, ABD 1970. Bilateral reduction in [3H]T-401 binding was observed in the cerebral cortex and the hippocampus few days after status epilepticus that further declined to a level of around 30% compared to the control. No change in binding was observed in either the hypothalamus nor the white matter at any time point. Direct comparison to [3H]UCB-J binding to synaptic vesicle glycoprotein 2 A (SV2A), another protein localized in the pre-synapse, revealed that while binding to MAGL remained low in the chronic phase, SV2A was increased significantly in some cortical areas. SIGNIFICANCE These data show that MAGL is reduced in the cerebral cortex and hippocampus in a chronic epilepsy model and indicate that MAGL inhibitors may further reduce MAGL activity in the treatment resistant epilepsy patient.
Collapse
Affiliation(s)
- Jens D Mikkelsen
- Neurobiology Research Unit, University Hospital Rigshospitalet, Copenhagen, Denmark; Institute of Neuroscience, University of Copenhagen, Denmark.
| | - Sanjay S Aripaka
- Neurobiology Research Unit, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Cansu B Egilmez
- Physiology Department, Faculty of Medicine, Izmir Katip Celebi University, Izmir, Turkey
| | - Burcu A Pazarlar
- Neurobiology Research Unit, University Hospital Rigshospitalet, Copenhagen, Denmark; Institute of Neuroscience, University of Copenhagen, Denmark; Physiology Department, Faculty of Medicine, Izmir Katip Celebi University, Izmir, Turkey
| |
Collapse
|
3
|
Takahata K, Seki C, Kimura Y, Kubota M, Ichise M, Sano Y, Yamamoto Y, Tagai K, Shimada H, Kitamura S, Matsuoka K, Endo H, Shinotoh H, Kawamura K, Zhang MR, Takado Y, Higuchi M. First-in-human in vivo undefined imaging and quantification of monoacylglycerol lipase in the brain: a PET study with 18F-T-401. Eur J Nucl Med Mol Imaging 2022; 49:3150-3161. [PMID: 35022846 DOI: 10.1007/s00259-021-05671-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 12/26/2021] [Indexed: 11/04/2022]
Abstract
PURPOSE Monoacylglycerol lipase (MAGL) regulates cannabinoid neurotransmission and the pro-inflammatory arachidonic acid pathway by degrading endocannabinoids. MAGL inhibitors may accordingly act as cannabinoid-potentiating and anti-inflammatory agents. Although MAGL dysfunction has been implicated in neuropsychiatric disorders, it has never been visualized in vivo in human brain. The primary objective of the current study was to visualize MAGL in the human brain using the novel PET ligand 18F-T-401. METHODS Seven healthy males underwent 120-min dynamic 18F-T-401-PET scans with arterial blood sampling. Six subjects also underwent a second PET scan with 18F-T-401 within 2 weeks of the first scan. For quantification of MAGL in the human brain, kinetic analyses using one- and two-tissue compartment models (1TCM and 2TCM, respectively), along with multilinear analysis (MA1) and Logan graphical analysis, were performed. Time-stability and test-retest reproducibility of 18F-T-401-PET were also evaluated. RESULTS 18F-T-401 showed rapid uptake and gradual washout from the brain. Logan graphical analysis showed linearity in all subjects, indicating reversible radioligand kinetics. Using a metabolite-corrected arterial input function, MA1 estimated regional total distribution volume (VT) values by best identifiability. VT values were highest in the cerebral cortex, moderate in the thalamus and putamen, and lowest in white matter and the brainstem, which was in agreement with regional MAGL expression in the human brain. Time-stability analysis showed that MA1 estimated VT values with a minimal bias even using truncated 60-min scan data. Test-retest reliability was also excellent with the use of MA1. CONCLUSIONS Here, we provide the first demonstration of in vivo visualization of MAGL in the human brain. 18F-T-401 showed excellent test-retest reliability, reversible kinetics, and stable estimation of VT values consistent with known regional MAGL expressions. PET with 18F-T-401-PET is promising tool for measurement of central MAGL.
Collapse
Affiliation(s)
- Keisuke Takahata
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan. .,Department of Neuro-Psychiatry, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, Japan.
| | - Chie Seki
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan
| | - Yasuyuki Kimura
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan.,Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, 7-430 Morioka, Obu, Aichi, Japan
| | - Manabu Kubota
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan.,Department of Psychiatry, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawara-cho, Sakyo-ku, Kyoto, Japan
| | - Masanori Ichise
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan.,Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, 7-430 Morioka, Obu, Aichi, Japan
| | - Yasunori Sano
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan
| | - Yasuharu Yamamoto
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan
| | - Kenji Tagai
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan
| | - Hitoshi Shimada
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan.,Department of Functional Neurology & Neurosurgery, Center for Integrated Human Brain Science, Brain Research Institute, Niigata University, 1-757 Asahimachi-Dori, Chuo, Niigata, Niigata, Japan
| | - Soichiro Kitamura
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan
| | - Kiwamu Matsuoka
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan
| | - Hironobu Endo
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan
| | - Hitoshi Shinotoh
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan
| | - Kazunori Kawamura
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage, Chiba, Chiba, Japan
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage, Chiba, Chiba, Japan
| | - Yuhei Takado
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan
| | - Makoto Higuchi
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba, 263-8555, Japan
| |
Collapse
|