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Zammit M, Kao CM, Zhang HJ, Tsai HM, Holderman N, Mitchell S, Tanios E, Bhuiyan M, Freifelder R, Kucharski A, Green WN, Mukherjee J, Chen CT. Evaluation of an Image-Derived Input Function for Kinetic Modeling of Nicotinic Acetylcholine Receptor-Binding PET Ligands in Mice. Int J Mol Sci 2023; 24:15510. [PMID: 37958495 PMCID: PMC10650787 DOI: 10.3390/ijms242115510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/18/2023] [Accepted: 10/21/2023] [Indexed: 11/15/2023] Open
Abstract
Positron emission tomography (PET) radioligands that bind with high-affinity to α4β2-type nicotinic receptors (α4β2Rs) allow for in vivo investigations of the mechanisms underlying nicotine addiction and smoking cessation. Here, we investigate the use of an image-derived arterial input function and the cerebellum for kinetic analysis of radioligand binding in mice. Two radioligands were explored: 2-[18F]FA85380 (2-FA), displaying similar pKa and binding affinity to the smoking cessation drug varenicline (Chantix), and [18F]Nifene, displaying similar pKa and binding affinity to nicotine. Time-activity curves of the left ventricle of the heart displayed similar distribution across wild type mice, mice lacking the β2-subunit for ligand binding, and acute nicotine-treated mice, whereas reference tissue binding displayed high variation between groups. Binding potential estimated from a two-tissue compartment model fit of the data with the image-derived input function were higher than estimates from reference tissue-based estimations. Rate constants of radioligand dissociation were very slow for 2-FA and very fast for Nifene. We conclude that using an image-derived input function for kinetic modeling of nicotinic PET ligands provides suitable results compared to reference tissue-based methods and that the chemical properties of 2-FA and Nifene are suitable to study receptor response to nicotine addiction and smoking cessation therapies.
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Affiliation(s)
- Matthew Zammit
- Department of Radiology, University of Chicago, Chicago, IL 60637, USA
| | - Chien-Min Kao
- Department of Radiology, University of Chicago, Chicago, IL 60637, USA
| | - Hannah J. Zhang
- Department of Radiology, University of Chicago, Chicago, IL 60637, USA
| | - Hsiu-Ming Tsai
- Department of Radiology, University of Chicago, Chicago, IL 60637, USA
| | | | - Samuel Mitchell
- Department of Radiology, University of Chicago, Chicago, IL 60637, USA
| | - Eve Tanios
- Department of Radiology, University of Chicago, Chicago, IL 60637, USA
| | - Mohammed Bhuiyan
- Department of Radiology, University of Chicago, Chicago, IL 60637, USA
| | | | - Anna Kucharski
- Department of Radiology, University of Chicago, Chicago, IL 60637, USA
- Fermi National Accelerator Laboratory, Batavia, IL 60510, USA
| | - William N. Green
- Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Jogeshwar Mukherjee
- Department of Radiological Sciences, University of California, Irvine, CA 92697, USA
| | - Chin-Tu Chen
- Department of Radiology, University of Chicago, Chicago, IL 60637, USA
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Zhang HJ, Zammit M, Kao CM, Govind AP, Mitchell S, Holderman N, Bhuiyan M, Freifelder R, Kucharski A, Zhuang X, Mukherjee J, Chen CT, Green WN. Trapping of Nicotinic Acetylcholine Receptor Ligands Assayed by In Vitro Cellular Studies and In Vivo PET Imaging. J Neurosci 2023; 43:2-13. [PMID: 36028313 PMCID: PMC9838697 DOI: 10.1523/jneurosci.2484-21.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 08/07/2022] [Accepted: 08/13/2022] [Indexed: 01/19/2023] Open
Abstract
A question relevant to nicotine addiction is how nicotine and other nicotinic receptor membrane-permeant ligands, such as the anti-smoking drug varenicline (Chantix), distribute in brain. Ligands, like varenicline, with high pKa and high affinity for α4β2-type nicotinic receptors (α4β2Rs) are trapped in intracellular acidic vesicles containing α4β2Rs in vitro Nicotine, with lower pKa and α4β2R affinity, is not trapped. Here, we extend our results by imaging nicotinic PET ligands in vivo in male and female mouse brain and identifying the trapping brain organelle in vitro as Golgi satellites (GSats). Two PET 18F-labeled imaging ligands were chosen: [18F]2-FA85380 (2-FA) with varenicline-like pKa and affinity and [18F]Nifene with nicotine-like pKa and affinity. [18F]2-FA PET-imaging kinetics were very slow consistent with 2-FA trapping in α4β2R-containing GSats. In contrast, [18F]Nifene kinetics were rapid, consistent with its binding to α4β2Rs but no trapping. Specific [18F]2-FA and [18F]Nifene signals were eliminated in β2 subunit knock-out (KO) mice or by acute nicotine (AN) injections demonstrating binding to sites on β2-containing receptors. Chloroquine (CQ), which dissipates GSat pH gradients, reduced [18F]2-FA distributions while having little effect on [18F]Nifene distributions in vivo consistent with only [18F]2-FA trapping in GSats. These results are further supported by in vitro findings where dissipation of GSat pH gradients blocks 2-FA trapping in GSats without affecting Nifene. By combining in vitro and in vivo imaging, we mapped both the brain-wide and subcellular distributions of weak-base nicotinic receptor ligands. We conclude that ligands, such as varenicline, are trapped in neurons in α4β2R-containing GSats, which results in very slow release long after nicotine is gone after smoking.SIGNIFICANCE STATEMENT Mechanisms of nicotine addiction remain poorly understood. An earlier study using in vitro methods found that the anti-smoking nicotinic ligand, varenicline (Chantix) was trapped in α4β2R-containing acidic vesicles. Using a fluorescent-labeled high-affinity nicotinic ligand, this study provided evidence that these intracellular acidic vesicles were α4β2R-containing Golgi satellites (GSats). In vivo PET imaging with F-18-labeled nicotinic ligands provided additional evidence that differences in PET ligand trapping in acidic vesicles were the cause of differences in PET ligand kinetics and subcellular distributions. These findings combining in vitro and in vivo imaging revealed new mechanistic insights into the kinetics of weak base PET imaging ligands and the subcellular mechanisms underlying nicotine addiction.
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Affiliation(s)
- Hannah J Zhang
- Department of Radiology, University of Chicago, Chicago, Illinois 60637
| | - Matthew Zammit
- Department of Radiology, University of Chicago, Chicago, Illinois 60637
| | - Chien-Min Kao
- Department of Radiology, University of Chicago, Chicago, Illinois 60637
| | - Anitha P Govind
- Department of Neurobiology, University of Chicago, Chicago, Illinois 60637
| | - Samuel Mitchell
- Department of Radiology, University of Chicago, Chicago, Illinois 60637
| | | | - Mohammed Bhuiyan
- Department of Radiology, University of Chicago, Chicago, Illinois 60637
| | | | - Anna Kucharski
- Department of Radiology, University of Chicago, Chicago, Illinois 60637
| | - Xiaoxi Zhuang
- Department of Neurobiology, University of Chicago, Chicago, Illinois 60637
| | - Jogeshwar Mukherjee
- Departments of Preclinical Imaging and Radiological Sciences, University of California, Irvine, California 92697
| | - Chin-Tu Chen
- Department of Radiology, University of Chicago, Chicago, Illinois 60637
| | - William N Green
- Department of Neurobiology, University of Chicago, Chicago, Illinois 60637
- Marine Biological Laboratory, Woods Hole, Massachusetts 02543
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Zhang HJ, Mitchell S, Fang YH, Tsai HM, Piao L, Ousta A, Leoni L, Chen CT, Sharp WW. Assessment of Brain Glucose Metabolism Following Cardiac Arrest by [ 18F]FDG Positron Emission Tomography. Neurocrit Care 2020; 34:64-72. [PMID: 32358767 DOI: 10.1007/s12028-020-00984-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
BACKGROUND Cardiac arrest (CA) patients who survived by cardiopulmonary resuscitation (CPR) can present different levels of neurological deficits ranging from minor cognitive impairments to persistent vegetative state and brain death. The pathophysiology of the resulting brain injury is poorly understood, and whether changes in post-CA brain metabolism contribute to the injury are unknown. Here we utilized [18F]fluorodeoxyglucose (FDG)-Positron emission tomography (PET) to study in vivo cerebral glucose metabolism 72 h following CA in a murine CA model. METHODS Anesthetized and ventilated adult C57BL/6 mice underwent 12-min KCl-induced CA followed by CPR. Seventy-two hours following CA, surviving mice were intraperitoneally injected with [18F]FDG (~ 186 µCi/200 µL) and imaged on Molecubes preclinical micro-PET/computed tomography (CT) imaging systems after a 30-min awake uptake period. Brain [18F]FDG uptake was determined by the VivoQuant software on fused PET/CT images with the 3D brain atlas. Upon completion of Positron emission tomography (PET) imaging, remaining [18F]FDG radioactivity in the brain, heart, and liver was determined using a gamma counter. RESULTS Global increases in brain [18F]FDG uptake in post-CA mice were observed compared to shams and controls. The median standardized uptake value of [18F]FDG for CA animals was 1.79 versus sham 1.25 (p < 0.05) and control animals 0.78 (p < 0.01). This increased uptake was consistent throughout the 60-min imaging period and across all brain regions reaching statistical significance in the midbrain, pons, and medulla. Biodistribution analyses of various key organs yielded similar observations that the median [18F]FDG uptake for brain was 7.04%ID/g tissue for CA mice versus 5.537%ID/g tissue for sham animals, p < 0.05). CONCLUSIONS This study has successfully applied [18F]FDG-PET/CT to measure changes in brain metabolism in a murine model of asystolic CA. Our results demonstrate increased [18F]FDG uptake in the brain 72 h following CA, suggesting increased metabolic demand in the case of severe neurological injury. Further study is warranted to determine the etiology of these changes.
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Affiliation(s)
- Hannah J Zhang
- Department of Radiology, University of Chicago, 5814 S Maryland Avenue, Chicago, IL, 60637, USA
| | - Samuel Mitchell
- Department of Radiology, University of Chicago, 5814 S Maryland Avenue, Chicago, IL, 60637, USA
| | - Yong-Hu Fang
- Department of Medicine, Section of Emergency Medicine, University of Chicago, 5841 S Maryland Avenue, Chicago, IL, 60637, USA
| | - Hsiu-Ming Tsai
- Office of Shared Research Facilities, University of Chicago, 5814 S Maryland Avenue, Chicago, IL, 60637, USA
| | - Lin Piao
- Department of Medicine, Section of Emergency Medicine, University of Chicago, 5841 S Maryland Avenue, Chicago, IL, 60637, USA
| | - Alaa Ousta
- Department of Medicine, Section of Emergency Medicine, University of Chicago, 5841 S Maryland Avenue, Chicago, IL, 60637, USA
| | - Lara Leoni
- Office of Shared Research Facilities, University of Chicago, 5814 S Maryland Avenue, Chicago, IL, 60637, USA
| | - Chin-Tu Chen
- Department of Radiology, University of Chicago, 5814 S Maryland Avenue, Chicago, IL, 60637, USA
| | - Willard W Sharp
- Department of Medicine, Section of Emergency Medicine, University of Chicago, 5841 S Maryland Avenue, Chicago, IL, 60637, USA.
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Kim H, Han H. Computer-Aided Multi-Target Management of Emergent Alzheimer's Disease. Bioinformation 2018; 14:167-180. [PMID: 29983487 PMCID: PMC6016757 DOI: 10.6026/97320630014167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 04/29/2018] [Accepted: 04/30/2018] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease (AD) represents an enormous global health burden in terms of human suffering and economic cost. AD management requires a shift from the prevailing paradigm targeting pathogenesis to design and develop effective drugs with adequate success in clinical trials. Therefore, it is of interest to report a review on amyloid beta (Aβ) effects and other multi-targets including cholinesterase, NFTs, tau protein and TNF associated with brain cell death to be neuro-protective from AD. It should be noted that these molecules have been generated either by target-based or phenotypic methods. Hence, the use of recent advancements in nanomedicine and other natural compounds screening tools as a feasible alternative for circumventing specific liabilities is realized. We review recent developments in the design and identification of neuro-degenerative compounds against AD generated using current advancements in computational multi-target modeling algorithms reflected by theragnosis (combination of diagnostic tests and therapy) concern.
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Affiliation(s)
- Hyunjo Kim
- Department of Medical Informatics, Ajou Medical University Hospital, Suwon, Kyeounggido province, South Korea
| | - Hyunwook Han
- Department of Informatics, School of Medicine, CHA University, Seongnam, South Korea
- Institute of Basic Medical Sciences, School of Medicine, CHA University, Seongnam, South Korea
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