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Singh P, Adhikari A, Singh D, Gond C, Tiwari AK. The 18-kDa Translocator Protein PET Tracers as a Diagnostic Marker for Neuroinflammation: Development and Current Standing. ACS OMEGA 2022; 7:14412-14429. [PMID: 35557664 PMCID: PMC9089361 DOI: 10.1021/acsomega.2c00588] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/05/2022] [Indexed: 05/13/2023]
Abstract
Translocator protein (TSPO, 18 kDa) is an evolutionary, well-preserved, and tryptophan-rich 169-amino-acid protein which localizes on the contact sites between the outer and inner mitochondrial membranes of steroid-synthesizing cells. This mitochondrial protein is implicated in an extensive range of cellular activities, including steroid synthesis, cholesterol transport, apoptosis, mitochondrial respiration, and cell proliferation. The upregulation of TSPO is well documented in diverse disease conditions including neuroinflammation, cancer, brain injury, and inflammation in peripheral organs. On the basis of these outcomes, TSPO has been assumed to be a fascinating subcellular target for early stage imaging of the diseased state and for therapeutic purposes. The main outline of this Review is to give an update on dealing with the advances made in TSPO PET tracers for neuroinflammation, synchronously emphasizing the approaches applied for the design and advancement of new tracers with reference to their structure-activity relationship (SAR).
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Affiliation(s)
- Priya Singh
- Department
of Chemistry, Babasaheb Bhimrao Ambedkar
University (A Central University), Lucknow, 226025, Uttar Pradesh, India
| | - Anupriya Adhikari
- Department
of Chemistry, Babasaheb Bhimrao Ambedkar
University (A Central University), Lucknow, 226025, Uttar Pradesh, India
| | - Deepika Singh
- Department
of Chemistry, Babasaheb Bhimrao Ambedkar
University (A Central University), Lucknow, 226025, Uttar Pradesh, India
| | - Chandraprakash Gond
- Department
of Chemistry, Babasaheb Bhimrao Ambedkar
University (A Central University), Lucknow, 226025, Uttar Pradesh, India
| | - Anjani Kumar Tiwari
- Department
of Chemistry, Babasaheb Bhimrao Ambedkar
University (A Central University), Lucknow, 226025, Uttar Pradesh, India
- Address:
Department of Chemistry,
Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh. Tel.: +91-7503381343. Fax: +91-522-2440821. E-mail:
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2
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Auriemma R, Sponchioni M, Capasso Palmiero U, Rossino G, Rossetti A, Marsala A, Collina S, Sacchetti A, Moscatelli D, Peviani M. Synthesis and Characterization of a "Clickable" PBR28 TSPO-Selective Ligand Derivative Suitable for the Functionalization of Biodegradable Polymer Nanoparticles. NANOMATERIALS 2021; 11:nano11071693. [PMID: 34203263 PMCID: PMC8308144 DOI: 10.3390/nano11071693] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/21/2021] [Accepted: 06/22/2021] [Indexed: 02/04/2023]
Abstract
Reactive microgliosis is a pathological hallmark that accompanies neuronal demise in many neurodegenerative diseases, ranging from acute brain/spinal cord injuries to chronic diseases, such as amyotrophic lateral sclerosis (ALS), Alzheimer’s disease (AD) and age-related dementia. One strategy to assess and monitor microgliosis is to use positron emission tomography (PET) by exploiting radioligands selective for the 18 kDa translocator protein (TSPO) which is highly upregulated in the brain in pathological conditions. Several TSPO ligands have been developed and validated, so far. Among these, PBR28 has been widely adopted for PET imaging at both preclinical and clinical levels, thanks to its high brain penetration and high selectivity. For this reason, PBR28 represents a good candidate for functionalization strategies, where this ligand could be exploited to drive selective targeting of TSPO-expressing cells. Since the PBR28 structure lacks functional moieties that could be exploited for derivatization, in this work we explored a synthetic pathway for the synthesis of a PBR28 derivative carrying an alkyne group (PBR-alkyne), enabling the fast conjugation of the ligand through azide-alkyne cycloaddition, also known as click-chemistry. As a proof of concept, we demonstrated in silico that the derivatized PBR28 ligand maintains the capability to fit into the TSPO binding pocked, and we successfully exploited PBR-alkyne to decorate zwitterionic biodegradable polymer nanoparticles (NPs) resulting in efficient internalization in cultured microglia-like cell lines.
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Affiliation(s)
- Renato Auriemma
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Via Mancinelli 7, 20131 Milano, Italy; (R.A.); (A.R.); (A.S.); (D.M.)
| | - Mattia Sponchioni
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Via Mancinelli 7, 20131 Milano, Italy; (R.A.); (A.R.); (A.S.); (D.M.)
- Correspondence: (M.S.); (M.P.)
| | - Umberto Capasso Palmiero
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland;
| | - Giacomo Rossino
- Department of Drug Sciences, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy; (G.R.); (S.C.)
| | - Arianna Rossetti
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Via Mancinelli 7, 20131 Milano, Italy; (R.A.); (A.R.); (A.S.); (D.M.)
| | - Andrea Marsala
- Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy;
| | - Simona Collina
- Department of Drug Sciences, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy; (G.R.); (S.C.)
| | - Alessandro Sacchetti
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Via Mancinelli 7, 20131 Milano, Italy; (R.A.); (A.R.); (A.S.); (D.M.)
| | - Davide Moscatelli
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Via Mancinelli 7, 20131 Milano, Italy; (R.A.); (A.R.); (A.S.); (D.M.)
| | - Marco Peviani
- Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy;
- Gene Therapy Program, Dana Farber/Boston Children’s Cancer and Blood Disorders Center, 450 Brookline Ave., Boston, MA 02215, USA
- Harvard Medical School, Boston, MA 02115, USA
- Correspondence: (M.S.); (M.P.)
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3
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Foss CA, Sanchez-Bautista J, Jain SK. Imaging Macrophage-associated Inflammation. Semin Nucl Med 2018; 48:242-245. [PMID: 29626941 DOI: 10.1053/j.semnuclmed.2017.12.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Macrophages belong to the mononuclear phagocyte system comprising closely related cells of bone marrow origin. Activated macrophages are critical in several diseases such as tuberculosis, sarcoidosis, Crohn's disease, and atherosclerosis. Noninvasive imaging techniques that can specifically image activated macrophages could therefore help in differentiating various forms of inflammatory diseases and to monitor therapeutic responses.
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Affiliation(s)
- Catherine A Foss
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD; Center for Infection and Inflammation Imaging Research, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Julian Sanchez-Bautista
- Center for Infection and Inflammation Imaging Research, Johns Hopkins University School of Medicine, Baltimore, MD; Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Sanjay K Jain
- Center for Infection and Inflammation Imaging Research, Johns Hopkins University School of Medicine, Baltimore, MD; Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD.
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4
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Alam MM, Lee J, Lee SY. Recent Progress in the Development of TSPO PET Ligands for Neuroinflammation Imaging in Neurological Diseases. Nucl Med Mol Imaging 2017; 51:283-296. [PMID: 29242722 DOI: 10.1007/s13139-017-0475-8] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 12/08/2016] [Accepted: 02/06/2017] [Indexed: 12/13/2022] Open
Abstract
Neuroinflammation is heavily associated with various neurological diseases including Alzheimer's disease, Parkinson's disease, multiple sclerosis, and stroke. It is strongly characterized by the activation of microglia which can be visualized using position emission tomography (PET). Traditionally, translocator protein 18 kDa (TSPO) has been the preferred target for imaging the inflammatory progression of the microglial component. TSPO is expressed in the outer mitochondrial membrane and present in very low concentrations in the healthy human brain, but is markedly upregulated in response to brain injury and inflammation. Due to its value as a marker of microglial activation and subsequent utility for evaluating neuroinflammation in CNS disorders, several classes of TSPO radioligands have been developed and evaluated. However, the application of these second-generation TSPO radiotracers has been subject to several limiting factors, including a polymorphism that affects TSPO binding. This review focuses on recent developments in TSPO imaging, as well as current limitations and suggestions for future directions from a medical imaging perspective.
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Affiliation(s)
- Md Maqusood Alam
- Neuroscience Research Institute, Gachon University, Incheon, 20565 South Korea
| | - Jihye Lee
- Neuroscience Research Institute, Gachon University, Incheon, 20565 South Korea
| | - Sang-Yoon Lee
- Neuroscience Research Institute, Gachon University, Incheon, 20565 South Korea.,Department of Neuroscience, College of Medicine, Gachon University, Incheon, 21936 South Korea
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Lee J, Cheong IK, Lee SY. Successful application of a neutral organic base, 1,8-bis(tetramethylguanidino)naphthalene (TMGN), for the radiosynthesis of [ 11C]raclopride. Appl Radiat Isot 2016; 118:382-388. [PMID: 27894050 DOI: 10.1016/j.apradiso.2016.10.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 08/05/2016] [Accepted: 10/10/2016] [Indexed: 10/20/2022]
Abstract
[11C]Raclopride is one of the most popular PET tracers used in Parkinson's disease studies. We previously prepared [11C]raclopride with reasonable yields using NaOH as an inorganic base, but the reaction patterns fluctuated. In this study, we describe the successful application of a commercially available 'super basic' proton sponge, TMGN, as a base for the [11C]methylation step using [11C]CH3OTf. This novel TMGN method produced better radiochemical yields, as well as enhanced reproducibility and a reduction in side products. Under optimal conditions (1.2 equiv. of TMGN), the radiochemical yield was 14.4±0.2% (ndc, EOS, n=5) and the specific activity was 66.6±13.3 GBq/mmol (n=5).
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Affiliation(s)
- Jihye Lee
- Neuroscience Research Institute, Gachon University, 24, Namdong-daero 774 beon-gil, Namdong-gu, Incheon, Korea
| | - Il-Koo Cheong
- Gachon Advanced Institute for Health Science and Technology, Graduate School, Gachon University, 155, Gaetbeol-ro, Yeonsu-gu, Incheon, Korea
| | - Sang-Yoon Lee
- Neuroscience Research Institute, Gachon University, 24, Namdong-daero 774 beon-gil, Namdong-gu, Incheon, Korea; Department of Neuroscience, College of Medicine, Gachon University, 191, Hambangmoe-ro, Yeonsu-gu, Incheon, Korea.
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Damont A, Médran-Navarrete V, Cacheux F, Kuhnast B, Pottier G, Bernards N, Marguet F, Puech F, Boisgard R, Dollé F. Novel Pyrazolo[1,5-a]pyrimidines as Translocator Protein 18 kDa (TSPO) Ligands: Synthesis, in Vitro Biological Evaluation, [(18)F]-Labeling, and in Vivo Neuroinflammation PET Images. J Med Chem 2015; 58:7449-64. [PMID: 26280386 DOI: 10.1021/acs.jmedchem.5b00932] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A series of novel pyrazolo[1,5-a]pyrimidines, closely related to N,N-diethyl-2-(2-(4-(2-fluoroethoxy)phenyl)-5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-yl)acetamide (2, DPA-714), were synthesized and biologically in vitro evaluated for their potential to bind the translocator protein 18 kDa (TSPO), a protein today recognized as an early biomarker of neuroinflammatory processes. This series is composed of fluoroalkyl- and fluoroalkynyl- analogues, prepared from a common iodinated intermediate via Sonogashira coupling reactions. All derivatives displayed subnanomolar affinity for the TSPO (0.37 to 0.86 nM), comparable to that of 2 (0.91 nM). Two of them were radiolabeled with fluorine-18, and their biodistribution was investigated by in vitro autoradiography and positron emission tomography (PET) imaging on a rodent model of neuroinflammation. Brain uptake and local accumulation of both compounds in the AMPA-mediated lesion confirm their potential as in vivo PET-radiotracers. In particular, [(18)F]23 exhibited a significantly higher ipsi- to contralateral ratio at 60 min than the parent molecule [(18)F]2 in vivo.
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Affiliation(s)
- Annelaure Damont
- CEA, I2BM, Service Hospitalier Frédéric Joliot, Orsay, France.,Inserm/CEA/Université Paris Sud, UMR 1023-ERL 9218 CNRS, IMIV, Orsay, France
| | - Vincent Médran-Navarrete
- CEA, I2BM, Service Hospitalier Frédéric Joliot, Orsay, France.,Inserm/CEA/Université Paris Sud, UMR 1023-ERL 9218 CNRS, IMIV, Orsay, France
| | - Fanny Cacheux
- CEA, I2BM, Service Hospitalier Frédéric Joliot, Orsay, France.,Inserm/CEA/Université Paris Sud, UMR 1023-ERL 9218 CNRS, IMIV, Orsay, France
| | - Bertrand Kuhnast
- CEA, I2BM, Service Hospitalier Frédéric Joliot, Orsay, France.,Inserm/CEA/Université Paris Sud, UMR 1023-ERL 9218 CNRS, IMIV, Orsay, France
| | - Géraldine Pottier
- CEA, I2BM, Service Hospitalier Frédéric Joliot, Orsay, France.,Inserm/CEA/Université Paris Sud, UMR 1023-ERL 9218 CNRS, IMIV, Orsay, France
| | - Nicholas Bernards
- CEA, I2BM, Service Hospitalier Frédéric Joliot, Orsay, France.,Inserm/CEA/Université Paris Sud, UMR 1023-ERL 9218 CNRS, IMIV, Orsay, France
| | | | | | - Raphaël Boisgard
- CEA, I2BM, Service Hospitalier Frédéric Joliot, Orsay, France.,Inserm/CEA/Université Paris Sud, UMR 1023-ERL 9218 CNRS, IMIV, Orsay, France
| | - Frédéric Dollé
- CEA, I2BM, Service Hospitalier Frédéric Joliot, Orsay, France.,Inserm/CEA/Université Paris Sud, UMR 1023-ERL 9218 CNRS, IMIV, Orsay, France
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Solingapuram Sai KK, Gage D, Nader M, Mach RH, Mintz A. Improved Automated Radiosynthesis of [(11)C]PBR28. Sci Pharm 2015; 83:413-27. [PMID: 26839827 PMCID: PMC4727796 DOI: 10.3797/scipharm.1505-06] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 06/19/2015] [Indexed: 11/22/2022] Open
Abstract
Microglial activation is commonly identified by elevated levels of the 18 kDa translocator protein (TSPO) in response to several inflammatory processes. [(11)C]PBR28 is one of the most promising PET tracers to image TSPO in both human and non-human primates. In this study, we optimized the radiolabeling procedure of [(11)C]PBR28 for higher radiochemical yield, radiochemical purity, and specific activity, which can be easily translated to any automated module for clinical trials. Time-activity curves (TACs) derived from the dynamic PET imaging of male rhesus monkey brains demonstrated that [(11)C]PBR28 had suitable kinetics with radiotracer accumulation observed in the caudate, putamen, cerebellum, and frontal cortex region.
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Affiliation(s)
| | - Don Gage
- Department of Radiology, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157, USA
| | - Mike Nader
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157, USA
| | - Robert H Mach
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Akiva Mintz
- Department of Radiology, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157, USA
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Brody AL, Okita K, Shieh J, Liang L, Hubert R, Mamoun M, Farahi J, Mandelkern MA. Radiation dosimetry and biodistribution of the translocator protein radiotracer [(11)C]DAA1106 determined with PET/CT in healthy human volunteers. Nucl Med Biol 2014; 41:871-5. [PMID: 25156039 PMCID: PMC4192057 DOI: 10.1016/j.nucmedbio.2014.07.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 07/11/2014] [Accepted: 07/15/2014] [Indexed: 10/25/2022]
Abstract
INTRODUCTION When microglia become activated (an integral part of neuroinflammation), cellular morphology changes and expression of translocator protein (TSPO) 18 kDa is increased. Over the past several years, [(11)C]DAA1106 has emerged as a reliable radiotracer for labeling TSPO with high affinity during positron emission tomography (PET) scanning. While [(11)C]DAA1106 PET scanning has been used in several research studies, a radiation dosimetry study of this radiotracer in humans has not yet been published. METHODS Twelve healthy participants underwent full body dynamic [(11)C]DAA1106 PET scanning, with 8 sequential whole body scans (approximately 12 bed positions each), following a single injection. Regions of interest were drawn manually, and time activity curves (TACs) were obtained for 15 organs. OLINDA/EXM 1.1 was used to compute radiation absorbed doses to the target organs, as well as effective dose (ED) and effective dose equivalent (EDE). RESULTS The ED and EDE were 4.06 ± 0.58 μSv/MBq and 5.89 ± 0.83 μSv/MBq, respectively. The highest absorbed doses were to the heart wall, kidney, liver, pancreas, and spleen. TACs revealed that peak dose rates are during the first scan (at 6 min) for all organs other than the urinary bladder wall, which had its peak dose rate during the fourth scan (at 30 min). CONCLUSIONS The recently developed radiotracer [(11)C]DAA1106 has its EDE and target-organ absorbed dose such that, for a single administration, its radiation dosimetry is well within the U.S. FDA guidelines for basic research studies in adults. This dose level implies that the dosimetry for multiple [(11)C]DAA1106 scans within a given year also falls within FDA guidelines, and this favorable property makes this radiotracer suitable for examining microglial activation repeatedly over time, which may in the future be useful for longitudinal tracking of disease progression and monitoring of therapy response in conditions marked by neuroinflammation (e.g., head trauma and multiple sclerosis).
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Affiliation(s)
- Arthur L Brody
- Department of Research, VA Greater Los Angeles Healthcare System (VAGLAHS), 11301 Wilshire Blvd., Los Angeles, CA 90073; Department of Psychiatry, University of California at Los Angeles, 300 UCLA Medical Plaza, Suite 2200, Los Angeles, CA 90095.
| | - Kyoji Okita
- Department of Research, VA Greater Los Angeles Healthcare System (VAGLAHS), 11301 Wilshire Blvd., Los Angeles, CA 90073; UCLA Laboratory of Molecular Imaging, 760 Westwood Plaza C8-538, Los Angeles, CA 90095
| | - Jennifer Shieh
- Department of Research, VA Greater Los Angeles Healthcare System (VAGLAHS), 11301 Wilshire Blvd., Los Angeles, CA 90073
| | - Lidia Liang
- Department of Research, VA Greater Los Angeles Healthcare System (VAGLAHS), 11301 Wilshire Blvd., Los Angeles, CA 90073
| | - Robert Hubert
- Department of Research, VA Greater Los Angeles Healthcare System (VAGLAHS), 11301 Wilshire Blvd., Los Angeles, CA 90073
| | - Michael Mamoun
- Department of Research, VA Greater Los Angeles Healthcare System (VAGLAHS), 11301 Wilshire Blvd., Los Angeles, CA 90073
| | - Judah Farahi
- Department of Imaging, VAGLAHS, 11301 Wilshire Blvd., Los Angeles, CA 90073
| | - Mark A Mandelkern
- Department of Imaging, VAGLAHS, 11301 Wilshire Blvd., Los Angeles, CA 90073; Department of Physics, University of California at Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697
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Shao X, Schnau PL, Fawaz M, Scott PJH. Enhanced radiosyntheses of [¹¹C]raclopride and [¹¹C]DASB using ethanolic loop chemistry. Nucl Med Biol 2013; 40:109-16. [PMID: 23123138 PMCID: PMC3514660 DOI: 10.1016/j.nucmedbio.2012.09.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 09/25/2012] [Accepted: 09/28/2012] [Indexed: 10/27/2022]
Abstract
INTRODUCTION To improve the synthesis and quality control of carbon-11 labeled radiopharmaceuticals, we report the fully automated loop syntheses of [¹¹C]raclopride and [¹¹C]DASB using ethanol as the only organic solvent for synthesis module cleaning, carbon-11 methylation, HPLC purification, and reformulation. METHODS Ethanolic loop chemistry is fully automated using a GE TRACERLab FX(C-Pro) synthesis module, and is readily adaptable to any other carbon-11 synthesis apparatus. Precursors (1 mg) were dissolved in ethanol (100 μL) and loaded into the HPLC loop. [¹¹C]MeOTf was passed through the HPLC loop and then the labeled products were purified by semi-preparative HPLC and reformulated into ethanolic saline. RESULTS Both [¹¹C]raclopride (3.7% RCY; >95% RCP; SA=20831 Ci/mmol; n=64) and [¹¹C]DASB, both with (3.0% RCY; >95% RCP; SA=15152Ci/mmol; n=9) and without (3.0% RCY; >95% RCP; SA=10931 Ci/mmol; n=3) sodium ascorbate, have been successfully prepared using the described methodology. Doses are suitable for human use and the described methods are now employed for routine clinical production of both radiopharmaceuticals at the University of Michigan. CONCLUSIONS Ethanolic loop chemistry is a powerful technique for preparing [¹¹C]raclopride and [¹¹C]DASB, and we are in the process of adapting it for other carbon-11 radiopharmaceuticals prepared in our laboratories ([¹¹C]PMP, [¹¹C]PBR28 etc.).
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Affiliation(s)
- Xia Shao
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Paul L. Schnau
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Maria Fawaz
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Peter J. H. Scott
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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10
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Fully automated synthesis of PET TSPO radioligands [11C]DAA1106 and [18F]FEDAA1106. Appl Radiat Isot 2012; 70:965-73. [DOI: 10.1016/j.apradiso.2012.03.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 02/09/2012] [Accepted: 03/05/2012] [Indexed: 11/17/2022]
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11
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Kuhnast B, Damont A, Hinnen F, Catarina T, Demphel S, Le Helleix S, Coulon C, Goutal S, Gervais P, Dollé F. [18F]DPA-714, [18F]PBR111 and [18F]FEDAA1106-selective radioligands for imaging TSPO 18 kDa with PET: automated radiosynthesis on a TRACERLAb FX-FN synthesizer and quality controls. Appl Radiat Isot 2011; 70:489-97. [PMID: 22104496 DOI: 10.1016/j.apradiso.2011.10.015] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 10/19/2011] [Accepted: 10/25/2011] [Indexed: 10/15/2022]
Abstract
Imaging of TSPO 18 kDa with PET is more and more considered as a relevant biomarker of inflammation in numerous diseases. Development of new radiotracers for TSPO 18 kDa has seen acceleration in the last years and the challenge today is to make available large amounts of such a radiotracer in compliance with GMP standards for application in humans. We present in this technical note automated productions of [(18)F]DPA-714, [(18)F]PBR111 and [(18)F]FEDAA1106, three promising radiotracers for TSPO 18 kDa imaging, using a TRACERlab FX-FN synthesizer. This note also includes the quality control data of the validation batches for the manufacturing qualification of clinical production of [(18)F]DPA-714.
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12
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Damont A, Boisgard R, Kuhnast B, Lemée F, Raggiri G, Scarf AM, Da Pozzo E, Selleri S, Martini C, Tavitian B, Kassiou M, Dollé F. Synthesis of 6-[¹⁸F]fluoro-PBR28, a novel radiotracer for imaging the TSPO 18 kDa with PET. Bioorg Med Chem Lett 2011; 21:4819-22. [PMID: 21741237 DOI: 10.1016/j.bmcl.2011.06.048] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 06/09/2011] [Accepted: 06/11/2011] [Indexed: 11/19/2022]
Abstract
6-Fluoro-PBR28 (N-(6-fluoro-4-phenoxypyridin-3-yl)-N-(2-methoxybenzyl)acetamide), a fluorinated analogue of the recently developed TSPO 18 kDa ligand PBR28, was synthesized and labelled with fluorine-18. 6-Fluoro-PBR28 and its 6-chloro/6-bromo counterparts were synthesized in six chemical steps and obtained in 16%, 10% and 19% overall yields, respectively. Labelling with fluorine-18 was performed in one single step (chlorine/bromine-for-fluorine heteroaromatic substitution) using a Zymate-XP robotic system affording HPLC-purified, ready-to-inject, 6-[(18)F]fluoro-PBR28 (>95% radiochemically pure). Non-decay-corrected overall yields were 9-10% and specific radioactivities ranged from 74 to 148 GBq/μmol. In vitro binding experiments, dynamic μPET studies performed in a rat model of acute neuroinflammation (unilaterally, AMPA-induced, striatum-lesioned rats) and ex vivo autoradiography on the same model demonstrated the potential of 6-[(18)F]fluoro-PBR28 to image the TSPO 18 kDa using PET.
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13
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In vivo imaging and quantitative analysis of TSPO in rat peripheral tissues using small-animal PET with [18F]FEDAC. Nucl Med Biol 2010; 37:853-60. [DOI: 10.1016/j.nucmedbio.2010.04.183] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Revised: 04/19/2010] [Accepted: 04/19/2010] [Indexed: 11/23/2022]
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Hoareau R, Scott PJ. A novel one-pot palladium-mediated synthesis of N-[(2-hydroxyphenyl)methyl]-N-(4-phenoxy-3-pyridinyl) acetamide, the precursor to [11C]PBR28, a PET biomarker for the peripheral benzodiazepine receptor. Tetrahedron Lett 2010. [DOI: 10.1016/j.tetlet.2010.04.089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Binding of NIR-conPK and NIR-6T to astrocytomas and microglial cells: evidence for a protein related to TSPO. PLoS One 2009; 4:e8271. [PMID: 20020060 PMCID: PMC2792720 DOI: 10.1371/journal.pone.0008271] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Accepted: 11/12/2009] [Indexed: 12/02/2022] Open
Abstract
PK 11195 and DAA1106 bind with high-affinity to the translocator protein (TSPO, formerly known as the peripheral benzodiazepine receptor). TSPO expression in glial cells increases in response to cytokines and pathological stimuli. Accordingly, [11C]-PK 11195 and [11C]-DAA1106 are recognized molecular imaging (MI) agents capable of monitoring changes in TSPO expression occurring in vivo and in response to various neuropathologies. Here we tested the pharmacological characteristics and TSPO-monitoring potential of two novel MI agents: NIR-conPK and NIR-6T. NIR-conPK is an analogue of PK 11195 conjugated to the near-infrared (NIR) emitting fluorophore: IRDye 800CW. NIR-6T is a DAA1106 analogue also conjugated to IRDye 800CW. We found that NIR-6T competed for [3H]-PK 11195 binding in astrocytoma cell homogenates with nanomolar affinity, but did not exhibit specific binding in intact astrocytoma cells in culture, indicating that NIR-6T is unlikely to constitute a useful MI agent for monitoring TSPO expression in intact cells. Conversely, we found that NIR-conPK did not compete for [3H]-PK 11195 binding in astrocytoma cell homogenate, but exhibited specific binding in intact astrocytoma cells in culture with nanomolar affinity, suggesting that NIR-conPK binds to a protein distinct, but related to, TSPO. Accordingly, treating intact astrocytoma cells and microglia in culture with cytokines led to significant changes in the amount of NIR-conPK specific binding without corresponding change in TSPO expression. Remarkably, the cytokine-induced changes in the protein targeted by NIR-conPK in intact microglia were selective, since IFN-γ (but not TNFα and TGFβ) increased the amount of NIR-conPK specific binding in these cells. Together these results suggest that NIR-conPK binds to a protein that is related to TSPO, and expressed by astrocytomas and microglia. Our results also suggest that the expression of this protein is increased by specific cytokines, and thus allows for the monitoring of a particular subtype of microglia activation.
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Wilson AA, Garcia A, Houle S, Vasdev N. Utility of commercial radiosynthetic modules in captive solvent [11C]-methylation reactions. J Labelled Comp Radiopharm 2009. [DOI: 10.1002/jlcr.1618] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Wang M, Yoder KK, Gao M, Mock BH, Xu XM, Saykin AJ, Hutchins GD, Zheng QH. Fully automated synthesis and initial PET evaluation of [11C]PBR28. Bioorg Med Chem Lett 2009; 19:5636-9. [PMID: 19716298 DOI: 10.1016/j.bmcl.2009.08.051] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 08/05/2009] [Accepted: 08/05/2009] [Indexed: 11/30/2022]
Abstract
Fully automated synthesis and initial PET evaluation of a TSPO radioligand, [11C]PBR28 (N-(2-[11C]methoxybenzyl)-N-(4-phenoxypyridin-3-yl)acetamide), are reported. These results facilitate the potential preclinical and clinical PET studies of [11C]PBR28 in animals and humans.
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Affiliation(s)
- Min Wang
- Department of Radiology, Indiana University School of Medicine, 950 West Walnut Street, Room 427, Indianapolis, IN 46202, USA
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Gulyás B, Makkai B, Kása P, Gulya K, Bakota L, Várszegi S, Beliczai Z, Andersson J, Csiba L, Thiele A, Dyrks T, Suhara T, Suzuki K, Higuchi M, Halldin C. A comparative autoradiography study in post mortem whole hemisphere human brain slices taken from Alzheimer patients and age-matched controls using two radiolabelled DAA1106 analogues with high affinity to the peripheral benzodiazepine receptor (PBR) system. Neurochem Int 2009; 54:28-36. [DOI: 10.1016/j.neuint.2008.10.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Accepted: 10/01/2008] [Indexed: 10/21/2022]
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Nuclear imaging of neuroinflammation: a comprehensive review of [11C]PK11195 challengers. Eur J Nucl Med Mol Imaging 2008; 35:2304-19. [DOI: 10.1007/s00259-008-0908-9] [Citation(s) in RCA: 324] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Accepted: 07/17/2008] [Indexed: 12/22/2022]
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20
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Briard E, Zoghbi SS, Imaizumi M, Gourley JP, Shetty HU, Hong J, Cropley V, Fujita M, Innis RB, Pike VW. Synthesis and Evaluation in Monkey of Two Sensitive 11C-Labeled Aryloxyanilide Ligands for Imaging Brain Peripheral Benzodiazepine Receptors In Vivo. J Med Chem 2007; 51:17-30. [DOI: 10.1021/jm0707370] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Emmanuelle Briard
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892
| | - Sami S. Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892
| | - Masao Imaizumi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892
| | - Jonathan P. Gourley
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892
| | - H. Umesha Shetty
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892
| | - Jinsoo Hong
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892
| | - Vanessa Cropley
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892
| | - Masahiro Fujita
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892
| | - Robert B. Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892
| | - Victor W. Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892
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