1
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Chauveau F, Winkeler A, Chalon S, Boutin H, Becker G. PET imaging of neuroinflammation: any credible alternatives to TSPO yet? Mol Psychiatry 2024:10.1038/s41380-024-02656-9. [PMID: 38997465 DOI: 10.1038/s41380-024-02656-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 06/26/2024] [Accepted: 07/01/2024] [Indexed: 07/14/2024]
Abstract
Over the last decades, the role of neuroinflammation in neuropsychiatric conditions has attracted an exponentially growing interest. A key driver for this trend was the ability to image brain inflammation in vivo using PET radioligands targeting the Translocator Protein 18 kDa (TSPO), which is known to be expressed in activated microglia and astrocytes upon inflammatory events as well as constitutively in endothelial cells. TSPO is a mitochondrial protein that is expressed mostly by microglial cells upon activation but is also expressed by astrocytes in some conditions and constitutively by endothelial cells. Therefore, our current understanding of neuroinflammation dynamics is hampered by the lack of alternative targets available for PET imaging. We performed a systematic search and review on radiotracers developed for neuroinflammation PET imaging apart from TSPO. The following targets of interest were identified through literature screening (including previous narrative reviews): P2Y12R, P2X7R, CSF1R, COX (microglial targets), MAO-B, I2BS (astrocytic targets), CB2R & S1PRs (not specific of a single cell type). We determined the level of development and provided a scoping review for each target. Strikingly, astrocytic biomarker MAO-B has progressed in clinical investigations the furthest, while few radiotracers (notably targeting S1P1Rs, CSF1R) are being implemented in clinical investigations. Other targets such as CB2R and P2X7R have proven disappointing in clinical studies (e.g. poor signal, lack of changes in disease conditions, etc.). While astrocytic targets are promising, development of new biomarkers and tracers specific for microglial activation has proven challenging.
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Affiliation(s)
- Fabien Chauveau
- Université Claude Bernard Lyon 1, Centre de Recherche en Neurosciences de Lyon, Inserm U1028, CNRS UMR5292, BIORAN, Groupement Hospitalier Est - CERMEP, 59 boulevard Pinel, 69677, Bron, Cedex, France
| | - Alexandra Winkeler
- Université Paris-Saclay, Inserm, CNRS, CEA, BioMaps, Service Hospitalier Frédéric Joliot, 4 place du général Leclerc, 91401, Orsay, France
| | - Sylvie Chalon
- UMR 1253 iBrain, Université de Tours - INSERM, Bâtiment Planiol, UFR de Médecine, 10 Boulevard Tonnellé, 37032, Tours, Cedex 01, France
| | - Hervé Boutin
- UMR 1253 iBrain, Université de Tours - INSERM, Bâtiment Planiol, UFR de Médecine, 10 Boulevard Tonnellé, 37032, Tours, Cedex 01, France.
| | - Guillaume Becker
- Université Claude Bernard Lyon 1, Centre de Recherche en Neurosciences de Lyon, Inserm U1028, CNRS UMR5292, BIORAN, Groupement Hospitalier Est - CERMEP, 59 boulevard Pinel, 69677, Bron, Cedex, France
- Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail, 14 rue Pierre et Marie Curie, 94701, Maisons-Alfort, Cedex, France
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2
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Lamba M, Singh PR, Bandyopadhyay A, Goswami A. Synthetic 18F labeled biomolecules that are selective and promising for PET imaging: major advances and applications. RSC Med Chem 2024; 15:1899-1920. [PMID: 38911154 PMCID: PMC11187557 DOI: 10.1039/d4md00033a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 04/14/2024] [Indexed: 06/25/2024] Open
Abstract
The concept of positron emission tomography (PET) based imaging was developed more than 40 years ago. It has been a widely adopted technique for detecting and staging numerous diseases in clinical settings, particularly cancer, neuro- and cardio-diseases. Here, we reviewed the evolution of PET and its advantages over other imaging modalities in clinical settings. Primarily, this review discusses recent advances in the synthesis of 18F radiolabeled biomolecules in light of the widely accepted performance for effective PET. The discussion particularly emphasizes the 18F-labeling chemistry of carbohydrates, lipids, amino acids, oligonucleotides, peptides, and protein molecules, which have shown promise for PET imaging in recent decades. In addition, we have deliberated on how 18F-labeled biomolecules enable the detection of metabolic changes at the cellular level and the selective imaging of gross anatomical localization via PET imaging. In the end, the review discusses the future perspective of PET imaging to control disease in clinical settings. We firmly believe that collaborative multidisciplinary research will further widen the comprehensive applications of PET approaches in the clinical management of cancer and other pathological outcomes.
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Affiliation(s)
- Manisha Lamba
- Department of Chemistry, Indian Institute of Technology Birla Farms Ropar Punjab-140001 India
| | - Prasoon Raj Singh
- Department of Chemistry, Indian Institute of Technology Birla Farms Ropar Punjab-140001 India
| | - Anupam Bandyopadhyay
- Department of Chemistry, Indian Institute of Technology Birla Farms Ropar Punjab-140001 India
| | - Avijit Goswami
- Department of Chemistry, Indian Institute of Technology Birla Farms Ropar Punjab-140001 India
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3
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Santos L, Moreira JN, Abrunhosa A, Gomes C. Brain metastasis: An insight into novel molecular targets for theranostic approaches. Crit Rev Oncol Hematol 2024; 198:104377. [PMID: 38710296 DOI: 10.1016/j.critrevonc.2024.104377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 04/11/2024] [Accepted: 04/25/2024] [Indexed: 05/08/2024] Open
Abstract
Brain metastases (BrM) are common malignant lesions in the central nervous system, and pose a significant threat in advanced-stage malignancies due to delayed diagnosis and limited therapeutic options. Their distinct genomic profiles underscore the need for molecular profiling to tailor effective treatments. Recent advances in cancer biology have uncovered molecular drivers underlying tumor initiation, progression, and metastasis. This, coupled with the advances in molecular imaging technology and radiotracer synthesis, has paved the way for the development of innovative radiopharmaceuticals with enhanced specificity and affinity for BrM specific targets. Despite the challenges posed by the blood-brain barrier to effective drug delivery, several radiolabeled compounds have shown promise in detecting and targeting BrM. This manuscript provides an overview of the recent advances in molecular biomarkers used in nuclear imaging and targeted radionuclide therapy in both clinical and preclinical settings. Additionally, it explores potential theranostic applications addressing the unique challenges posed by BrM.
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Affiliation(s)
- Liliana Santos
- Institute for Nuclear Sciences Applied to Health (ICNAS) and Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), University of Coimbra, Coimbra 3000-548, Portugal; Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, Coimbra 3000-548, Portugal
| | - João Nuno Moreira
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra 3004-504, Portugal; Center for Innovative Biomedicine and Biotechnology Consortium (CIBB), University of Coimbra, Coimbra 3000-548, Portugal
| | - Antero Abrunhosa
- Institute for Nuclear Sciences Applied to Health (ICNAS) and Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), University of Coimbra, Coimbra 3000-548, Portugal
| | - Célia Gomes
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, Coimbra 3000-548, Portugal; Center for Innovative Biomedicine and Biotechnology Consortium (CIBB), University of Coimbra, Coimbra 3000-548, Portugal; Clinical Academic Center of Coimbra (CACC), Coimbra 3000-075, Portugal.
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4
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Gustavsson T, Herth MM, Sehlin D, Syvänen S. Indium-111 radiolabelling of a brain-penetrant Aβ antibody for SPECT imaging. Ups J Med Sci 2024; 129:10585. [PMID: 38863725 PMCID: PMC11165248 DOI: 10.48101/ujms.v129.10585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/12/2024] [Accepted: 04/12/2024] [Indexed: 06/13/2024] Open
Abstract
Background The development of bispecific antibodies that can traverse the blood-brain barrier has paved the way for brain-directed immunotherapy and when radiolabelled, immunoPET imaging. The objective of this study was to investigate how indium-111 (111In) radiolabelling with compatible chelators affects the brain delivery and peripheral biodistribution of the bispecific antibody RmAb158-scFv8D3, which binds to amyloid-beta (Aβ) and the transferrin receptor (TfR), in Aβ pathology-expressing tg-ArcSwe mice and aged-matched wild-type control mice. Methods Bispecific RmAb158-scFv8D3 (biAb) was radiolabelled with 111In using CHX-A"-DTPA, DOTA, or DOTA-tetrazine (DOTA-Tz). Affinity toward TfR and Aβ, as well as stability, was investigated in vitro. Mice were then intravenously administered with the three different radiolabelled biAb variants, and blood samples were collected for monitoring pharmacokinetics. Brain concentration was quantified after 2 and 72 h, and organ-specific retention was measured at 72 h by gamma counting. A subset of mice also underwent whole-body Single-photon emission computed tomography (SPECT) scanning at 72 h after injection. Following post-mortem isolation, the brains of tg-ArcSwe and WT mice were sectioned, and the spatial distribution of biAb was further investigated with autoradiography. Results All three [111In]biAb variants displayed similar blood pharmacokinetics and brain uptake at 2 h after administration. Radiolabelling did not compromise affinity, and all variants showed good stability, especially the DOTA-Tz variant. Whole-body SPECT scanning indicated high liver, spleen, and bone accumulation of all [111In]biAb variants. Subsequent ex vivo measurement of organ retention confirmed SPECT data, with retention in the spleen, liver, and bone - with very high bone marrow retention. Ex vivo gamma measurement of brain tissue, isolated at 72 h post-injection, and ex vivo autoradiography showed that WT mice, despite the absence of Aβ, exhibited comparable brain concentrations of [111In]biAb as those found in the tg-ArcSwe brain. Conclusions The successful 111In-labelling of biAb with retained binding to TfR and Aβ, and retained ability to enter the brain, demonstrated that 111In can be used to generate radioligands for brain imaging. A high degree of [111In]biAb in bone marrow and intracellular accumulation in brain tissue indicated some off-target interactions or potential interaction with intrabrain TfR resulting in a relatively high non-specific background signal.
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Affiliation(s)
- Tobias Gustavsson
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Matthias M. Herth
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Dag Sehlin
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
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5
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Shojaei M, Zhou Q, Palumbo G, Schaefer R, Kaskinoro J, Vehmaan-Kreula P, Bartenstein P, Brendel M, Edbauer D, Lindner S. Development and Preclinical Evaluation of a Copper-64-Labeled Antibody Targeting Glycine-Alanine Dipeptides for PET Imaging of C9orf72-Associated Amyotrophic Lateral Sclerosis/Frontotemporal Dementia. ACS Pharmacol Transl Sci 2024; 7:1404-1414. [PMID: 38751620 PMCID: PMC11091963 DOI: 10.1021/acsptsci.4c00037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 04/04/2024] [Accepted: 04/09/2024] [Indexed: 05/18/2024]
Abstract
Aggregating poly(glycine-alanine) (poly-GA) is derived from the unconventional translation of the pathogenic intronic hexanucleotide repeat expansion in the C9orf72 gene, which is the most common genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Poly-GA accumulates predominantly in neuronal cytoplasmic inclusions unique to C9orf72 ALS/FTD patients. Poly-GA is, therefore, a promising target for PET/CT imaging of FTD/ALS to monitor disease progression and therapeutic interventions. A novel 64Cu-labeled anti-GA antibody (mAb1A12) targeting the poly-GA protein was developed and evaluated in a transgenic mouse model. It was obtained with high radiochemical purity (RCP), radiochemical yield (RCY), and specific activity, and showed high stability in vitro and ex vivo and specifically bound to poly-GA. The affinity of NODAGA-mAb1A12 for poly-GA was not affected by this modification. [64Cu]Cu-NODAGA-mAb1A12 was injected into transgenic mice expressing GFP-(GA)175 in excitatory neurons driven by Camk2a-Cre and in control littermates. PET/CT imaging was performed at 2, 20, and 40 h post-injection (p.i.) and revealed a higher accumulation in the cortex in transgenic mice than in wild-type mice, as reflected by higher standardized uptake value ratios (SUVR) using the cerebellum as the reference region. The organs were isolated for biodistribution and ex vivo autoradiography. Autoradiography revealed a higher cortex-to-cerebellum ratio in the transgenic mice than in the controls. Results from autoradiography were validated by immunohistochemistry and poly-GA immunoassays. Moreover, we confirmed antibody uptake in the CNS in a pharmacokinetic study of the perfused tissues. In summary, [64Cu]Cu-NODAGA-mAb1A12 demonstrated favorable in vitro characteristics and an increased relative binding in poly-GA transgenic mice compared to wild-type mice in vivo. Our results with this first-in-class radiotracer suggested that targeting poly-GA is a promising approach for PET/CT imaging in FTD/ALS.
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Affiliation(s)
- Monireh Shojaei
- Department
of Nuclear Medicine, University Hospital,
LMU Munich, 81377 Munich, Germany
| | - Qihui Zhou
- German
Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
| | - Giovanna Palumbo
- Department
of Nuclear Medicine, University Hospital,
LMU Munich, 81377 Munich, Germany
| | - Rebecca Schaefer
- Department
of Nuclear Medicine, University Hospital,
LMU Munich, 81377 Munich, Germany
| | | | | | - Peter Bartenstein
- Department
of Nuclear Medicine, University Hospital,
LMU Munich, 81377 Munich, Germany
- Munich
Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Matthias Brendel
- Department
of Nuclear Medicine, University Hospital,
LMU Munich, 81377 Munich, Germany
- German
Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
- Munich
Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Dieter Edbauer
- German
Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
- Munich
Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Simon Lindner
- Department
of Nuclear Medicine, University Hospital,
LMU Munich, 81377 Munich, Germany
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6
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Schlein E, Rokka J, Odell LR, van den Broek SL, Herth MM, Battisti UM, Syvänen S, Sehlin D, Eriksson J. Synthesis and evaluation of fluorine-18 labelled tetrazines as pre-targeting imaging agents for PET. EJNMMI Radiopharm Chem 2024; 9:21. [PMID: 38446356 PMCID: PMC10917718 DOI: 10.1186/s41181-024-00250-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Accepted: 02/28/2024] [Indexed: 03/07/2024] Open
Abstract
BACKGROUND The brain is a challenging target for antibody-based positron emission tomography (immunoPET) imaging due to the restricted access of antibody-based ligands through the blood-brain barrier (BBB). To overcome this physiological obstacle, we have previously developed bispecific antibody ligands that pass through the BBB via receptor-mediated transcytosis. While these radiolabelled ligands have high affinity and specificity, their long residence time in the blood and brain, typical for large molecules, poses another challenge for PET imaging. A viable solution could be a two-step pre-targeting approach which involves the administration of a tagged antibody that accumulates at the target site in the brain and then clears from the blood, followed by administration of a small radiolabelled molecule with fast kinetics. This radiolabelled molecule can couple to the tagged antibody and thereby make the antibody localisation visible by PET imaging. The in vivo linkage can be achieved by using the inverse electron demand Diels-Alder reaction (IEDDA), with trans-cyclooctene (TCO) and tetrazine groups participating as reactants. In this study, two novel 18F-labelled tetrazines were synthesized and evaluated for their potential use as pre-targeting imaging agents, i.e., for their ability to rapidly enter the brain and, if unbound, to be efficiently cleared with minimal background retention. RESULTS The two compounds, a methyl tetrazine [18F]MeTz and an H-tetrazine [18F]HTz were radiolabelled using a two-step procedure via [18F]F-Py-TFP synthesized on solid support followed by amidation with amine-bearing tetrazines, resulting in radiochemical yields of 24% and 22%, respectively, and a radiochemical purity of > 96%. In vivo PET imaging was performed to assess their suitability for in vivo pre-targeting. Time-activity curves from PET-scans showed [18F]MeTz to be the more pharmacokinetically suitable agent, given its fast and homogenous distribution in the brain and rapid clearance. However, in terms of rection kinetics, H-tetrazines are advantageous, exhibiting faster reaction rates in IEDDA reactions with dienophiles like trans-cyclooctenes, making [18F]HTz potentially more beneficial for pre-targeting applications. CONCLUSION This study demonstrates a significant potential of [18F]MeTz and [18F]HTz as agents for pre-targeted PET brain imaging due to their efficient brain uptake, swift clearance and appropriate chemical stability.
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Affiliation(s)
- Eva Schlein
- Department of Public Health and Caring Sciences, Uppsala University, 751 85, Uppsala, Sweden
| | - Johanna Rokka
- Department of Public Health and Caring Sciences, Uppsala University, 751 85, Uppsala, Sweden
| | - Luke R Odell
- Department of Medicinal Chemistry, Uppsala University, 751 23, Uppsala, Sweden
| | | | - Matthias M Herth
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100, Copenhagen, Denmark
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Copenhagen University Hospital, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Umberto M Battisti
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, 751 85, Uppsala, Sweden
| | - Dag Sehlin
- Department of Public Health and Caring Sciences, Uppsala University, 751 85, Uppsala, Sweden
| | - Jonas Eriksson
- Department of Medicinal Chemistry, Uppsala University, 751 23, Uppsala, Sweden.
- PET Centre, Uppsala University Hospital, 751 85, Uppsala, Sweden.
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7
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Schlein E, Andersson KG, Dallas T, Syvänen S, Sehlin D. Reducing neonatal Fc receptor binding enhances clearance and brain-to-blood ratio of TfR-delivered bispecific amyloid-β antibody. MAbs 2024; 16:2339337. [PMID: 38634473 PMCID: PMC11028011 DOI: 10.1080/19420862.2024.2339337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 04/02/2024] [Indexed: 04/19/2024] Open
Abstract
Recent development of amyloid-β (Aβ)-targeted immunotherapies for Alzheimer's disease (AD) have highlighted the need for accurate diagnostic methods. Antibody-based positron emission tomography (PET) ligands are well suited for this purpose as they can be directed toward the same target as the therapeutic antibody. Bispecific, brain-penetrating antibodies can achieve sufficient brain concentrations, but their slow blood clearance remains a challenge, since it prolongs the time required to achieve a target-specific PET signal. Here, two antibodies were designed based on the Aβ antibody bapineuzumab (Bapi) - one monospecific IgG (Bapi) and one bispecific antibody with an antigen binding fragment (Fab) of the transferrin receptor (TfR) antibody 8D3 fused to one of the heavy chains (Bapi-Fab8D3) for active, TfR-mediated transport into the brain. A variant of each antibody was designed to harbor a mutation to the neonatal Fc receptor (FcRn) binding domain, to increase clearance. Blood and brain pharmacokinetics of radiolabeled antibodies were studied in wildtype (WT) and AD mice (AppNL-G-F). The FcRn mutation substantially reduced blood half-life of both Bapi and Bapi-Fab8D3. Bapi-Fab8D3 showed high brain uptake and the brain-to-blood ratio of its FcRn mutated form was significantly higher in AppNL-G-F mice than in WT mice 12 h after injection and increased further up to 168 h. Ex vivo autoradiography showed specific antibody retention in areas with abundant Aβ pathology. Taken together, these results suggest that reducing FcRn binding of a full-sized bispecific antibody increases the systemic elimination and could thereby drastically reduce the time from injection to in vivo imaging.
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Affiliation(s)
- Eva Schlein
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | | | - Tiffany Dallas
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Dag Sehlin
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
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Ren J, Jepson CE, Nealy SL, Kuhlmann CJ, Osuka S, Azolibe SU, Blucas MT, Nagaoka-Kamata Y, Kharlampieva E, Kamata M. Site-oriented conjugation of poly(2-methacryloyloxyethyl phosphorylcholine) for enhanced brain delivery of antibody. Front Cell Dev Biol 2023; 11:1214118. [PMID: 37920826 PMCID: PMC10618420 DOI: 10.3389/fcell.2023.1214118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 10/03/2023] [Indexed: 11/04/2023] Open
Abstract
Antibody therapeutics are limited in treating brain diseases due to poor blood-brain barrier (BBB) penetration. We have discovered that poly 2-methacryloyloxyethyl phosphorylcholine (PMPC), a biocompatible polymer, effectively facilitates BBB penetration via receptor-mediated transcytosis and have developed a PMPC-shell-based platform for brain delivery of therapeutic antibodies, termed nanocapsule. Yet, the platform results in functional loss of antibodies due to epitope masking by the PMPC polymer network, which necessitates the incorporation of a targeting moiety and degradable crosslinker to enable on-site antibody release. In this study, we developed a novel platform based on site-oriented conjugation of PMPC to the antibody, allowing it to maintain key functionalities of the original antibody. With an optimized PMPC chain length, the PMPC-antibody conjugate exhibited enhanced brain delivery while retaining epitope recognition, cellular internalization, and antibody-dependent cellular phagocytic activity. This simple formula incorporates only the antibody and PMPC without requiring additional components, thereby addressing the issues of the nanocapsule platform and paving the way for PMPC-based brain delivery strategies for antibodies.
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Affiliation(s)
- Jie Ren
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Chloe E. Jepson
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Sarah L. Nealy
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Charles J. Kuhlmann
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Satoru Osuka
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Stella Uloma Azolibe
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Madison T. Blucas
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Yoshiko Nagaoka-Kamata
- Department of Pathology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Eugenia Kharlampieva
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Masakazu Kamata
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
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9
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Shah S, Turner ML, Chen X, Ances BM, Hammoud DA, Tucker EW. The Promise of Molecular Imaging: Focus on Central Nervous System Infections. J Infect Dis 2023; 228:S311-S321. [PMID: 37788502 PMCID: PMC11009511 DOI: 10.1093/infdis/jiad223] [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] [Indexed: 10/05/2023] Open
Abstract
Central nervous system (CNS) infections can lead to high mortality and severe morbidity. Diagnosis, monitoring, and assessing response to therapy of CNS infections is particularly challenging with traditional tools, such as microbiology, due to the dangers associated with invasive CNS procedures (ie, biopsy or surgical resection) to obtain tissues. Molecular imaging techniques like positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging have long been used to complement anatomic imaging such as computed tomography (CT) and magnetic resonance imaging (MRI), for in vivo evaluation of disease pathophysiology, progression, and treatment response. In this review, we detail the use of molecular imaging to delineate host-pathogen interactions, elucidate antimicrobial pharmacokinetics, and monitor treatment response. We also discuss the utility of pathogen-specific radiotracers to accurately diagnose CNS infections and strategies to develop radiotracers that would cross the blood-brain barrier.
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Affiliation(s)
- Swati Shah
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Mitchell L Turner
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Xueyi Chen
- Department of Pediatrics, Center for Infection and Inflammation Imaging Research, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Beau M Ances
- Department of Neurology, Washington University, St Louis, Missouri, USA
| | - Dima A Hammoud
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Elizabeth W Tucker
- Department of Anesthesiology and Critical Care Medicine, Center for Infection and Inflammation Imaging Research, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
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10
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Cools R, Kerkhofs K, Leitao RCF, Bormans G. Preclinical Evaluation of Novel PET Probes for Dementia. Semin Nucl Med 2023; 53:599-629. [PMID: 37149435 DOI: 10.1053/j.semnuclmed.2023.03.004] [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: 03/15/2023] [Accepted: 03/24/2023] [Indexed: 05/08/2023]
Abstract
The development of novel PET imaging agents that selectively bind specific dementia-related targets can contribute significantly to accurate, differential and early diagnosis of dementia causing diseases and support the development of therapeutic agents. Consequently, in recent years there has been a growing body of literature describing the development and evaluation of potential new promising PET tracers for dementia. This review article provides a comprehensive overview of novel dementia PET probes under development, classified by their target, and pinpoints their preclinical evaluation pathway, typically involving in silico, in vitro and ex/in vivo evaluation. Specific target-associated challenges and pitfalls, requiring extensive and well-designed preclinical experimental evaluation assays to enable successful clinical translation and avoid shortcomings observed for previously developed 'well-established' dementia PET tracers are highlighted in this review.
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Affiliation(s)
- Romy Cools
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Kobe Kerkhofs
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium; NURA, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Renan C F Leitao
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Guy Bormans
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium.
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Esparza TJ, Su S, Francescutti CM, Rodionova E, Kim JH, Brody DL. Enhanced in vivo blood brain barrier transcytosis of macromolecular cargo using an engineered pH-sensitive mouse transferrin receptor binding nanobody. Fluids Barriers CNS 2023; 20:64. [PMID: 37620930 PMCID: PMC10463325 DOI: 10.1186/s12987-023-00462-z] [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: 04/26/2023] [Accepted: 08/10/2023] [Indexed: 08/26/2023] Open
Abstract
BACKGROUND The blood brain barrier limits entry of macromolecular diagnostic and therapeutic cargos. Blood brain barrier transcytosis via receptor mediated transport systems, such as the transferrin receptor, can be used to carry macromolecular cargos with variable efficiency. Transcytosis involves trafficking through acidified intracellular vesicles, but it is not known whether pH-dependent unbinding of transport shuttles can be used to improve blood brain barrier transport efficiency. METHODS A mouse transferrin receptor binding nanobody, NIH-mTfR-M1, was engineered to confer greater unbinding at pH 5.5 vs 7.4 by introducing multiple histidine mutations. The histidine mutant nanobodies were coupled to neurotensin for in vivo functional blood brain barrier transcytosis testing via central neurotensin-mediated hypothermia in wild-type mice. Multi-nanobody constructs including the mutant M1R56H, P96H, Y102H and two copies of the P2X7 receptor-binding 13A7 nanobody were produced to test proof-of-concept macromolecular cargo transport in vivo using quantitatively verified capillary depleted brain lysates and in situ histology. RESULTS The most effective histidine mutant, M1R56H, P96H, Y102H-neurotensin, caused > 8 °C hypothermia after 25 nmol/kg intravenous injection. Levels of the heterotrimeric construct M1R56H, P96H, Y102H-13A7-13A7 in capillary depleted brain lysates peaked at 1 h and were 60% retained at 8 h. A control construct with no brain targets was only 15% retained at 8 h. Addition of the albumin-binding Nb80 nanobody to make M1R56H, P96H, Y102H-13A7-13A7-Nb80 extended blood half-life from 21 min to 2.6 h. At 30-60 min, biotinylated M1R56H, P96H, Y102H-13A7-13A7-Nb80 was visualized in capillaries using in situ histochemistry, whereas at 2-16 h it was detected in diffuse hippocampal and cortical cellular structures. Levels of M1R56H, P96H, Y102H-13A7-13A7-Nb80 reached more than 3.5 percent injected dose/gram of brain tissue after 30 nmol/kg intravenous injection. However, higher injected concentrations did not result in higher brain levels, compatible with saturation and an apparent substrate inhibitory effect. CONCLUSION The pH-sensitive mouse transferrin receptor binding nanobody M1R56H, P96H, Y102H may be a useful tool for rapid and efficient modular transport of diagnostic and therapeutic macromolecular cargos across the blood brain barrier in mouse models. Additional development will be required to determine whether this nanobody-based shuttle system will be useful for imaging and fast-acting therapeutic applications.
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Affiliation(s)
- Thomas J Esparza
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc, Bethesda, MD, USA
| | - Shiran Su
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | | | - Elvira Rodionova
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Joong Hee Kim
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc, Bethesda, MD, USA
| | - David L Brody
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
- Center for Neuroscience and Regenerative Medicine, Bethesda, MD, USA.
- Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
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Faresjö R, Sehlin D, Syvänen S. Age, dose, and binding to TfR on blood cells influence brain delivery of a TfR-transported antibody. Fluids Barriers CNS 2023; 20:34. [PMID: 37170266 PMCID: PMC10173660 DOI: 10.1186/s12987-023-00435-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 04/27/2023] [Indexed: 05/13/2023] Open
Abstract
BACKGROUND Transferrin receptor 1 (TfR1) mediated brain delivery of antibodies could become important for increasing the efficacy of emerging immunotherapies in Alzheimer's disease (AD). However, age, dose, binding to TfR1 on blood cells, and pathology could influence the TfR1-mediated transcytosis of TfR1-binders across the blood-brain barrier (BBB). The aim of the study was, therefore, to investigate the impact of these factors on the brain delivery of a bispecific TfR1-transported Aβ-antibody, mAb3D6-scFv8D3, in comparison with the conventional antibody mAb3D6. METHODS Young (3-5 months) and aged (17-20 months) WT and tg-ArcSwe mice (AD model) were injected with 125I-labeled mAb3D6-scFv8D3 or mAb3D6. Three different doses were used in the study, 0.05 mg/kg (low dose), 1 mg/kg (high dose), and 10 mg/kg (therapeutic dose), with equimolar doses for mAb3D6. The dose-corrected antibody concentrations in whole blood, blood cells, plasma, spleen, and brain were evaluated at 2 h post-administration. Furthermore, isolated brains were studied by autoradiography, nuclear track emulsion, and capillary depletion to investigate the intrabrain distribution of the antibodies, while binding to blood cells was studied in vitro using blood isolated from young and aged mice. RESULTS The aged WT and tg-ArcSwe mice showed significantly lower brain concentrations of TfR-binding [125I]mAb3D6-scFv8D3 and higher concentrations in the blood cell fraction compared to young mice. For [125I]mAb3D6, no significant differences in blood or brain delivery were observed between young and aged mice or between genotypes. A low dose of [125I]mAb3D6-scFv8D3 was associated with increased relative parenchymal delivery, as well as increased blood cell distribution. Brain concentrations and relative parenchymal distribution of [125I]mAb3D6-scFv8D6 did not differ between tg-ArcSwe and WT mice at this early time point but were considerably increased compared to those observed for [125I]mAb3D6. CONCLUSION Age-dependent differences in blood and brain concentrations were observed for the bispecific antibody mAb3D6-scFv8D3 but not for the conventional Aβ antibody mAb3D6, indicating an age-related effect on TfR1-mediated brain delivery. The lowest dose of [125I]mAb3D6-scFv8D3 was associated with higher relative BBB penetration but, at the same time, a higher distribution to blood cells. Overall, Aβ-pathology did not influence the early brain distribution of the bispecific antibody. In summary, age and bispecific antibody dose were important factors determining brain delivery, while genotype was not.
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Affiliation(s)
- Rebecca Faresjö
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Dag Sehlin
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden.
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Gustavsson T, Metzendorf NG, Wik E, Roshanbin S, Julku U, Chourlia A, Nilsson P, Andersson KG, Laudon H, Hultqvist G, Syvänen S, Sehlin D. Long-term effects of immunotherapy with a brain penetrating Aβ antibody in a mouse model of Alzheimer's disease. Alzheimers Res Ther 2023; 15:90. [PMID: 37131196 PMCID: PMC10152635 DOI: 10.1186/s13195-023-01236-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 04/23/2023] [Indexed: 05/04/2023]
Abstract
BACKGROUND Brain-directed immunotherapy is a promising strategy to target amyloid-β (Aβ) deposits in Alzheimer's disease (AD). In the present study, we compared the therapeutic efficacy of the Aβ protofibril targeting antibody RmAb158 with its bispecific variant RmAb158-scFv8D3, which enters the brain by transferrin receptor-mediated transcytosis. METHODS AppNL-G-F knock-in mice received RmAb158, RmAb158-scFv8D3, or PBS in three treatment regimens. First, to assess the acute therapeutic effect, a single antibody dose was given to 5 months old AppNL-G-F mice, with evaluation after 3 days. Second, to assess the antibodies' ability to halt the progression of Aβ pathology, 3 months old AppNL-G-F mice received three doses during a week, with evaluation after 2 months. Reduction of RmAb158-scFv8D3 immunogenicity was explored by introducing mutations in the antibody or by depletion of CD4+ T cells. Third, to study the effects of chronic treatment, 7-month-old AppNL-G-F mice were CD4+ T cell depleted and treated with weekly antibody injections for 8 weeks, including a final diagnostic dose of [125I]RmAb158-scFv8D3, to determine its brain uptake ex vivo. Soluble Aβ aggregates and total Aβ42 were quantified with ELISA and immunostaining. RESULTS Neither RmAb158-scFv8D3 nor RmAb158 reduced soluble Aβ protofibrils or insoluble Aβ1-42 after a single injection treatment. After three successive injections, Aβ1-42 was reduced in mice treated with RmAb158, with a similar trend in RmAb158-scFv8D3-treated mice. Bispecific antibody immunogenicity was somewhat reduced by directed mutations, but CD4+ T cell depletion was used for long-term therapy. CD4+ T cell-depleted mice, chronically treated with RmAb158-scFv8D3, showed a dose-dependent increase in blood concentration of the diagnostic [125I]RmAb158-scFv8D3, while concentration was low in plasma and brain. Chronic treatment did not affect soluble Aβ aggregates, but a reduction in total Aβ42 was seen in the cortex of mice treated with both antibodies. CONCLUSIONS Both RmAb158 and its bispecific variant RmAb158-scFv8D3 achieved positive effects of long-term treatment. Despite its ability to efficiently enter the brain, the benefit of using the bispecific antibody in chronic treatment was limited by its reduced plasma exposure, which may be a result of interactions with TfR or the immune system. Future research will focus in new antibody formats to further improve Aβ immunotherapy.
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Affiliation(s)
- Tobias Gustavsson
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | | | - Elin Wik
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Sahar Roshanbin
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Ulrika Julku
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | | | - Per Nilsson
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden
| | | | | | | | - Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Dag Sehlin
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden.
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Willuweit A, Humpert S, Schöneck M, Endepols H, Burda N, Gremer L, Gering I, Kutzsche J, Shah NJ, Langen KJ, Neumaier B, Willbold D, Drzezga A. Evaluation of the 18F-labeled analog of the therapeutic all-D-enantiomeric peptide RD2 for amyloid β imaging. Eur J Pharm Sci 2023; 184:106421. [PMID: 36889654 DOI: 10.1016/j.ejps.2023.106421] [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: 09/30/2022] [Revised: 02/16/2023] [Accepted: 03/05/2023] [Indexed: 03/08/2023]
Abstract
Positron emission tomography (PET) imaging with radiotracers that bind to fibrillary amyloid β (Aβ) deposits is an important tool for the diagnosis of Alzheimer's disease (AD) and for the recruitment of patients into clinical trials. However, it has been suggested that rather than the fibrillary Aβ deposits, it is smaller, soluble Aβ aggregates that exert a neurotoxic effect and trigger AD pathogenesis. The aim of the current study is to develop a PET probe that is capable of detecting small aggregates and soluble Aβ oligomers for improved diagnosis and therapy monitoring. An 18F-labeled radioligand was prepared based on the Aβ-binding d-enantiomeric peptide RD2, which is currently being evaluated in clinical trials as a therapeutic agent to dissolve Aβ oligomers. 18F-labeling was carried out using palladium-catalyzed S-arylation of RD2 with 2-[18F]fluoro-5-iodopyridine ([18F]FIPy). Specific binding of [18F]RD2-cFPy to brain material from transgenic AD (APP/PS1) mice and AD patients was demonstrated with in vitro autoradiography. In vivo uptake and biodistribution of [18F]RD2-cFPy were evaluated using PET analyses in wild-type and transgenic APP/PS1 mice. Although brain penetration and brain wash-out kinetics of the radioligand were low, this study provides proof of principle for a PET probe based on a d-enantiomeric peptide binding to soluble Aβ species.
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Affiliation(s)
- Antje Willuweit
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany.
| | - Swen Humpert
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany
| | - Michael Schöneck
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany
| | - Heike Endepols
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany; Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne 50937, Germany; Department of Nuclear Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne 50937, Germany
| | - Nicole Burda
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany
| | - Lothar Gremer
- Institute of Biological Information Processing (IBI-7), Forschungszentrum Jülich, Jülich 52425, Germany; Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf 40225, Germany
| | - Ian Gering
- Institute of Biological Information Processing (IBI-7), Forschungszentrum Jülich, Jülich 52425, Germany
| | - Janine Kutzsche
- Institute of Biological Information Processing (IBI-7), Forschungszentrum Jülich, Jülich 52425, Germany
| | - N Jon Shah
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany; JARA - Brain - Translational Medicine, Aachen 52074, Germany; Department of Neurology, RWTH Aachen University, Aachen 52074, Germany
| | - Karl-Josef Langen
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany; Department of Nuclear Medicine, RWTH Aachen University, Aachen 52074, Germany
| | - Bernd Neumaier
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany; Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne 50937, Germany
| | - Dieter Willbold
- Institute of Biological Information Processing (IBI-7), Forschungszentrum Jülich, Jülich 52425, Germany; Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf 40225, Germany
| | - Alexander Drzezga
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany; Department of Nuclear Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne 50937, Germany
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Esparza TJ, Su S, Francescutti CM, Rodionova E, Kim JH, Brody DL. Enhanced in Vivo Blood Brain Barrier Transcytosis of Macromolecular Cargo Using an Engineered pH-sensitive Mouse Transferrin Receptor Binding Nanobody. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.26.538462. [PMID: 37333358 PMCID: PMC10274906 DOI: 10.1101/2023.04.26.538462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Background The blood brain barrier limits entry of macromolecular diagnostic and therapeutic cargos. Blood brain barrier transcytosis via receptor mediated transport systems, such as the transferrin receptor, can be used to carry macromolecular cargos with variable efficiency. Transcytosis involves trafficking through acidified intracellular vesicles, but it is not known whether pH-dependent unbinding of transport shuttles can be used to improve blood brain barrier transport efficiency. Methods A mouse transferrin receptor binding nanobody, NIH-mTfR-M1, was engineered to confer greater unbinding at pH 5.5 vs 7.4 by introducing multiple histidine mutations. The histidine mutant nanobodies were coupled to neurotensin for in vivo functional blood brain barrier transcytosis testing via central neurotensin-mediated hypothermia in wild-type mice. Multi-nanobody constructs including the mutant M1 R56H, P96H, Y102H and two copies of the P2X7 receptor-binding 13A7 nanobody were produced to test proof-of-concept macromolecular cargo transport in vivo using quantitatively verified capillary depleted brain lysates and in situ histology. Results The most effective histidine mutant, M1 R56H, P96H, Y102H -neurotensin, caused >8°C hypothermia after 25 nmol/kg intravenous injection. Levels of the heterotrimeric construct M1 56,96,102His -13A7-13A7 in capillary depleted brain lysates peaked at 1 hour and were 60% retained at 8 hours. A control construct with no brain targets was only 15% retained at 8 hours. Addition of the albumin-binding Nb80 nanobody to make M1 R56H, P96H, Y102H -13A7-13A7-Nb80 extended blood half-life from 21 minutes to 2.6 hours. At 30-60 minutes, biotinylated M1 R56H, P96H, Y102H -13A7-13A7-Nb80 was visualized in capillaries using in situ histochemistry, whereas at 2-16 hours it was detected in diffuse hippocampal and cortical cellular structures. Levels of M1 R56H, P96H, Y102H -13A7-13A7-Nb80 reached more than 3.5 percent injected dose/gram of brain tissue after 30 nmol/kg intravenous injection. However, higher injected concentrations did not result in higher brain levels, compatible with saturation and an apparent substrate inhibitory effect. Conclusion The pH-sensitive mouse transferrin receptor binding nanobody M1 R56H, P96H, Y102H may be a useful tool for rapid and efficient modular transport of diagnostic and therapeutic macromolecular cargos across the blood brain barrier in mouse models. Additional development will be required to determine whether this nanobody-based shuttle system will be useful for imaging and fast-acting therapeutic applications.
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Affiliation(s)
- Thomas J. Esparza
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, United States of America
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc, Bethesda, MD, United States of America
| | - Shiran Su
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, United States of America
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, United States of America
| | | | - Elvira Rodionova
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, United States of America
| | - Joong Hee Kim
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, United States of America
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc, Bethesda, MD, United States of America
| | - David L. Brody
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, United States of America
- Center for Neuroscience and Regenerative Medicine, Bethesda, MD, United States of America
- Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States of America
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Lopresti BJ, Royse SK, Mathis CA, Tollefson SA, Narendran R. Beyond monoamines: I. Novel targets and radiotracers for Positron emission tomography imaging in psychiatric disorders. J Neurochem 2023; 164:364-400. [PMID: 35536762 DOI: 10.1111/jnc.15615] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 10/18/2022]
Abstract
With the emergence of positron emission tomography (PET) in the late 1970s, psychiatry had access to a tool capable of non-invasive assessment of human brain function. Early applications in psychiatry focused on identifying characteristic brain blood flow and metabolic derangements using radiotracers such as [15 O]H2 O and [18 F]FDG. Despite the success of these techniques, it became apparent that more specific probes were needed to understand the neurochemical bases of psychiatric disorders. The first neurochemical PET imaging probes targeted sites of action of neuroleptic (dopamine D2 receptors) and psychoactive (serotonin receptors) drugs. Based on the centrality of monoamine dysfunction in psychiatric disorders and the measured success of monoamine-enhancing drugs in treating them, the next 30 years witnessed the development of an armamentarium of PET radiopharmaceuticals and imaging methodologies for studying monoamines. Continued development of monoamine-enhancing drugs over this time however was less successful, realizing only modest gains in efficacy and tolerability. As patent protection for many widely prescribed and profitable psychiatric drugs lapsed, drug development pipelines shifted away from monoamines in search of novel targets with the promises of improved efficacy, or abandoned altogether. Over this period, PET radiopharmaceutical development activities closely paralleled drug development priorities resulting in the development of new PET imaging agents for non-monoamine targets. Part one of this review will briefly survey novel PET imaging targets with relevance to the field of psychiatry, which include the metabotropic glutamate receptor type 5 (mGluR5), purinergic P2 X7 receptor, type 1 cannabinoid receptor (CB1 ), phosphodiesterase 10A (PDE10A), and describe radiotracers developed for these and other targets that have matured to human subject investigations. Current limitations of the targets and techniques will also be discussed.
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Affiliation(s)
- Brian J Lopresti
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Sarah K Royse
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Chester A Mathis
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Savannah A Tollefson
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Rajesh Narendran
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Departments of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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ImmunoPET Directed to the Brain: A New Tool for Preclinical and Clinical Neuroscience. Biomolecules 2023; 13:biom13010164. [PMID: 36671549 PMCID: PMC9855881 DOI: 10.3390/biom13010164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/08/2023] [Accepted: 01/10/2023] [Indexed: 01/14/2023] Open
Abstract
Immuno-positron emission tomography (immunoPET) is a non-invasive in vivo imaging method based on tracking and quantifying radiolabeled monoclonal antibodies (mAbs) and other related molecules, such as antibody fragments, nanobodies, or affibodies. However, the success of immunoPET in neuroimaging is limited because intact antibodies cannot penetrate the blood-brain barrier (BBB). In neuro-oncology, immunoPET has been successfully applied to brain tumors because of the compromised BBB. Different strategies, such as changes in antibody properties, use of physiological mechanisms in the BBB, or induced changes to BBB permeability, have been developed to deliver antibodies to the brain. These approaches have recently started to be applied in preclinical central nervous system PET studies. Therefore, immunoPET could be a new approach for developing more specific PET probes directed to different brain targets.
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18
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Bonvicini G, Syvänen S, Andersson KG, Haaparanta-Solin M, López-Picón F, Sehlin D. ImmunoPET imaging of amyloid-beta in a rat model of Alzheimer's disease with a bispecific, brain-penetrating fusion protein. Transl Neurodegener 2022; 11:55. [PMID: 36567338 PMCID: PMC9791759 DOI: 10.1186/s40035-022-00324-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 11/03/2022] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Hijacking the transferrin receptor (TfR) is an effective strategy to transport amyloid-beta (Aβ) immuno-positron emission tomography (immunoPET) ligands across the blood-brain barrier (BBB). Such ligands are more sensitive and specific than small-molecule ligands at detecting Aβ pathology in mouse models of Alzheimer's disease (AD). This study aimed to determine if this strategy would be as sensitive in rats and to assess how TfR affinity affects BBB transport of bispecific immunoPET radioligands. METHODS Two affinity variants of the rat TfR antibody, OX26, were chemically conjugated to a F(ab')2 fragment of the anti-Aβ antibody, bapineuzumab (Bapi), to generate two bispecific fusion proteins: OX265-F(ab')2-Bapi and OX2676-F(ab')2-Bapi. Pharmacokinetic analyses were performed 4 h and 70 h post-injection of radioiodinated fusion proteins in wild-type (WT) rats. [124I]I-OX265-F(ab')2-Bapi was administered to TgF344-AD and WT rats for in vivo PET imaging. Ex vivo distribution of injected [124I]I-OX265-F(ab')2-Bapi and Aβ pathology were assessed. RESULTS More [125I]I-OX265-F(ab')2-Bapi was taken up into the brain 4 h post-administration than [124I]I-OX2676-F(ab')2-Bapi. [124I]I-OX265-F(ab')2-Bapi PET visualized Aβ pathology with significantly higher signals in the TgF344-AD rats than in the WT littermates without Aβ pathology. The PET signals significantly correlated with Aβ levels in AD animals. CONCLUSION Affinity to TfR affects how efficiently a TfR-targeting bispecific fusion protein will cross the BBB, such that the higher-affinity bispecific fusion protein crossed the BBB more efficiently. Furthermore, bispecific immunoPET imaging of brain Aβ pathology using TfR-mediated transport provides good imaging contrast between TgF344-AD and WT rats, suggesting that this immunoPET strategy has the potential to be translated to higher species.
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Affiliation(s)
- Gillian Bonvicini
- grid.8993.b0000 0004 1936 9457Department of Public Health and Caring Sciences, Uppsala University, 751 85 Uppsala, Sweden ,BioArctic AB, 112 51 Stockholm, Sweden
| | - Stina Syvänen
- grid.8993.b0000 0004 1936 9457Department of Public Health and Caring Sciences, Uppsala University, 751 85 Uppsala, Sweden
| | | | - Merja Haaparanta-Solin
- grid.1374.10000 0001 2097 1371Preclinical Imaging Laboratory, Turku PET Centre, University of Turku, 20520 Turku, Finland ,grid.1374.10000 0001 2097 1371MediCity Research Laboratory, University of Turku, 20520 Turku, Finland
| | - Francisco López-Picón
- grid.1374.10000 0001 2097 1371Preclinical Imaging Laboratory, Turku PET Centre, University of Turku, 20520 Turku, Finland ,grid.1374.10000 0001 2097 1371MediCity Research Laboratory, University of Turku, 20520 Turku, Finland
| | - Dag Sehlin
- grid.8993.b0000 0004 1936 9457Department of Public Health and Caring Sciences, Uppsala University, 751 85 Uppsala, Sweden
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Ramasubramanian B, Reddy VS, Chellappan V, Ramakrishna S. Emerging Materials, Wearables, and Diagnostic Advancements in Therapeutic Treatment of Brain Diseases. BIOSENSORS 2022; 12:1176. [PMID: 36551143 PMCID: PMC9775999 DOI: 10.3390/bios12121176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/07/2022] [Accepted: 12/07/2022] [Indexed: 06/17/2023]
Abstract
Among the most critical health issues, brain illnesses, such as neurodegenerative conditions and tumors, lower quality of life and have a significant economic impact. Implantable technology and nano-drug carriers have enormous promise for cerebral brain activity sensing and regulated therapeutic application in the treatment and detection of brain illnesses. Flexible materials are chosen for implantable devices because they help reduce biomechanical mismatch between the implanted device and brain tissue. Additionally, implanted biodegradable devices might lessen any autoimmune negative effects. The onerous subsequent operation for removing the implanted device is further lessened with biodegradability. This review expands on current developments in diagnostic technologies such as magnetic resonance imaging, computed tomography, mass spectroscopy, infrared spectroscopy, angiography, and electroencephalogram while providing an overview of prevalent brain diseases. As far as we are aware, there hasn't been a single review article that addresses all the prevalent brain illnesses. The reviewer also looks into the prospects for the future and offers suggestions for the direction of future developments in the treatment of brain diseases.
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Affiliation(s)
- Brindha Ramasubramanian
- Department of Mechanical Engineering, Center for Nanofibers & Nanotechnology, National University of Singapore, Singapore 117574, Singapore
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), #08-03, 2 Fusionopolis Way, Innovis, Singapore 138634, Singapore
| | - Vundrala Sumedha Reddy
- Department of Mechanical Engineering, Center for Nanofibers & Nanotechnology, National University of Singapore, Singapore 117574, Singapore
| | - Vijila Chellappan
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), #08-03, 2 Fusionopolis Way, Innovis, Singapore 138634, Singapore
| | - Seeram Ramakrishna
- Department of Mechanical Engineering, Center for Nanofibers & Nanotechnology, National University of Singapore, Singapore 117574, Singapore
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20
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Edelmann MR. Radiolabelling small and biomolecules for tracking and monitoring. RSC Adv 2022; 12:32383-32400. [PMID: 36425706 PMCID: PMC9650631 DOI: 10.1039/d2ra06236d] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 11/02/2022] [Indexed: 11/13/2022] Open
Abstract
Radiolabelling small molecules with beta-emitters has been intensively explored in the last decades and novel concepts for the introduction of radionuclides continue to be reported regularly. New catalysts that induce carbon/hydrogen activation are able to incorporate isotopes such as deuterium or tritium into small molecules. However, these established labelling approaches have limited applicability for nucleic acid-based drugs, therapeutic antibodies, or peptides, which are typical of the molecules now being investigated as novel therapeutic modalities. These target molecules are usually larger (significantly >1 kDa), mostly multiply charged, and often poorly soluble in organic solvents. However, in preclinical research they often require radiolabelling in order to track and monitor drug candidates in metabolism, biotransformation, or pharmacokinetic studies. Currently, the most established approach to introduce a tritium atom into an oligonucleotide is based on a multistep synthesis, which leads to a low specific activity with a high level of waste and high costs. The most common way of tritiating peptides is using appropriate precursors. The conjugation of a radiolabelled prosthetic compound to a functional group within a protein sequence is a commonly applied way to introduce a radionuclide or a fluorescent tag into large molecules. This review highlights the state-of-the-art in different radiolabelling approaches for oligonucleotides, peptides, and proteins, as well as a critical assessment of the impact of the label on the properties of the modified molecules. Furthermore, applications of radiolabelled antibodies in biodistribution studies of immune complexes and imaging of brain targets are reported.
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Affiliation(s)
- Martin R Edelmann
- Department of Pharmacy and Pharmacology, University of Bath Bath BA2 7AY UK
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, Therapeutic Modalities, Small Molecule Research, Isotope Synthesis, F. Hoffmann-La Roche Ltd CH-4070 Basel Switzerland
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21
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Meier SR, Sehlin D, Syvänen S. Passive and receptor mediated brain delivery of an anti-GFAP nanobody. Nucl Med Biol 2022; 114-115:121-127. [PMID: 35487832 DOI: 10.1016/j.nucmedbio.2022.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/24/2022] [Accepted: 04/04/2022] [Indexed: 12/27/2022]
Abstract
PURPOSE Antibody-based constructs, engineered to enter the brain using transferrin receptor (TfR) mediated transcytosis, have been successfully used as PET radioligands for imaging of amyloid-beta (Aβ) in preclinical studies. However, these radioligands have been large and associated with long circulation times, i.e. non-optimal properties for neuroPET radioligands. The aim of this study was to investigate the in vivo brain delivery of the radiolabeled nanobody VHH-E9 that binds to glial fibrillary acidic protein (GFAP) expressed by reactive astrocytes, without and with fusion to a TfR binding moiety, as potential tools to detect neuroinflammation. METHODS Three protein constructs were recombinantly expressed: 1) The GFAP specific nanobody VHH-E9, 2) VHH-E9 fused to a single chain variable fragment of the TfR binding antibody 8D3 (scFv8D3) and 3) scFv8D3 alone. Brain delivery of the constructs was investigated at 2 h post injection. Binding to GFAP was studied with autoradiography while in vivo brain retention of [125I]VHH-E9 and [125I]VHH-E9-scFv8D3 was further investigated at 8 h, 24 h and 48 h in wild-type (WT), and at the same time points in transgenic mice (ArcSwe) that in addition to Aβ pathology also display neuroinflammation. RESULTS At 2 h after administration, [125I]VHH-E9-scFv8D3 and [125I]scFv8D3 displayed 3-fold higher brain concentrations than [125I]VHH-E9. In vitro autoradiography showed distinct binding of both [125I]VHH-E9-scFv8D3 and [125I]VHH-E9 to regions with abundant GFAP in ArcSwe mice. However, in vivo, there was no difference in brain concentrations between WT and ArcSwe at any of the studied time points. CONCLUSIONS Fused to scFv8D3, VHH-E9 displayed increased brain delivery. When radiolabeled and applied on brain sections, the bispecific construct was able to discriminate between WT and ArcSwe mice, but in vivo brain uptake and retention over time did not differ between WT and ArcSwe mice.
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Affiliation(s)
- Silvio R Meier
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Dag Sehlin
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden.
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22
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Schlein E, Syvänen S, Rokka J, Gustavsson T, Rossin R, Robillard M, Eriksson J, Sehlin D. Functionalization of Radiolabeled Antibodies to Enhance Peripheral Clearance for High Contrast Brain Imaging. Mol Pharm 2022; 19:4111-4122. [PMID: 36201682 PMCID: PMC9644377 DOI: 10.1021/acs.molpharmaceut.2c00536] [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] [Indexed: 11/30/2022]
Abstract
![]()
Small molecule imaging
agents such as [11C]PiB, which
bind to the core of insoluble amyloid-β (Aβ) fibrils,
are useful tools in Alzheimer’s disease (AD) research, diagnostics,
and drug development. However, the [11C]PiB PET signal
saturates early in the disease progression and does not detect soluble
or diffuse Aβ pathology which are believed to play important
roles in the disease progression. Antibodies, modified into a bispecific
format to enter the brain via receptor-mediated transcytosis, could
be a suitable alternative because of their diversity and high specificity
for their target. However, the circulation time of these antibodies
is long, resulting in an extended exposure to radiation and low imaging
contrast. Here, we explore two alternative strategies to enhance imaging
contrast by increasing clearance of the antibody ligand from blood.
The bispecific Aβ targeting antibody RmAb158-scFv8D3 and the
monospecific RmAb158 were radiolabeled and functionalized with either
α-d-mannopyranosylphenyl isothiocyanate (mannose) or
with trans-cyclooctene (TCO). While mannose can directly
mediate antibody clearance via the liver, TCO-modified antibody clearance
was induced by injection of a tetrazine-functionalized, liver-targeting
clearing agent (CA). In vivo experiments in wild type and AD transgenic
mice demonstrated the ability of both strategies to drastically shorten
the circulation time of RmAb158, while they had limited effect on
the bispecific variant RmAb158-8D3. Furthermore, single photon emission
computed tomography imaging with TCO-[125I]I-RmAb158 in
AD mice showed higher contrast 1 day after injection of the tetrazine-functionalized
CA. In conclusion, strategies to enhance the clearance of antibody-based
imaging ligands could allow imaging at earlier time points and thereby
open the possibility to combine antibodies with short-lived radionuclides
such as fluorine-18.
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Affiliation(s)
- Eva Schlein
- Department of Public Health and Caring Sciences, Uppsala University, 751 85 Uppsala, Sweden
| | - Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, 751 85 Uppsala, Sweden
| | - Johanna Rokka
- Department of Public Health and Caring Sciences, Uppsala University, 751 85 Uppsala, Sweden
| | - Tobias Gustavsson
- Department of Public Health and Caring Sciences, Uppsala University, 751 85 Uppsala, Sweden
| | - Raffaella Rossin
- Tagworks Pharmaceuticals, Toernooiveld 1, 6525 ED Nijmegen, Netherlands
| | - Marc Robillard
- Tagworks Pharmaceuticals, Toernooiveld 1, 6525 ED Nijmegen, Netherlands
| | - Jonas Eriksson
- PET Centre, Uppsala University Hospital, 751 85 Uppsala, Sweden.,Department of Medicinal Chemistry, Uppsala University, 751 23 Uppsala, Sweden
| | - Dag Sehlin
- Department of Public Health and Caring Sciences, Uppsala University, 751 85 Uppsala, Sweden
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23
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Lopes van den Broek S, Shalgunov V, García Vázquez R, Beschorner N, Bidesi NSR, Nedergaard M, Knudsen GM, Sehlin D, Syvänen S, Herth MM. Pretargeted Imaging beyond the Blood–Brain Barrier—Utopia or Feasible? Pharmaceuticals (Basel) 2022; 15:ph15101191. [PMID: 36297303 PMCID: PMC9612205 DOI: 10.3390/ph15101191] [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: 08/01/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 11/17/2022] Open
Abstract
Pretargeting is a promising nuclear imaging technique that allows for the usage of antibodies (Abs) with enhanced imaging contrast and reduced patient radiation burden. It is based on bioorthogonal chemistry with the tetrazine ligation—a reaction between trans-cyclooctenes (TCOs) and tetrazines (Tzs)—currently being the most popular reaction due to its high selectivity and reactivity. As Abs can be designed to bind specifically to currently ‘undruggable’ targets such as protein isoforms or oligomers, which play a crucial role in neurodegenerative diseases, pretargeted imaging beyond the BBB is highly sought after, but has not been achieved yet. A challenge in this respect is that large molecules such as Abs show poor brain uptake. Uptake can be increased by receptor mediated transcytosis; however, it is largely unknown if the achieved brain concentrations are sufficient for pretargeted imaging. In this study, we investigated whether the required concentrations are feasible to reach. As a model Ab, we used the bispecific anti-amyloid beta (Aβ) anti-transferrin receptor (TfR) Ab 3D6scFv8D3 and conjugated it to a different amount of TCOs per Ab and tested different concentrations in vitro. With this model in hand, we estimated the minimum required TCO concentration to achieve a suitable contrast between the high and low binding regions. The estimation was carried out using pretargeted autoradiography on brain sections of an Alzheimer’s disease mouse model. Biodistribution studies in wild-type (WT) mice were used to correlate how different TCO/Ab ratios alter the brain uptake. Pretargeted autoradiography showed that increasing the number of TCOs as well as increasing the TCO-Ab concentration increased the imaging contrast. A minimum brain concentration of TCOs for pretargeting purposes was determined to be 10.7 pmol/g in vitro. Biodistribution studies in WT mice showed a brain uptake of 1.1% ID/g using TCO-3D6scFv8D3 with 6.8 TCO/Ab. According to our estimations using the optimal parameters, pretargeted imaging beyond the BBB is not a utopia. Necessary brain TCO concentrations can be reached and are in the same order of magnitude as required to achieve sufficient contrast. This work gives a first estimate that pretargeted imaging is indeed possible with antibodies. This could allow the imaging of currently ‘undruggable’ targets and therefore be crucial to monitor (e.g., therapies for intractable neurodegenerative diseases).
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Affiliation(s)
- Sara Lopes van den Broek
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Vladimir Shalgunov
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Rocío García Vázquez
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Natalie Beschorner
- Center for Translational Neuromedicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Natasha S. R. Bidesi
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Gitte M. Knudsen
- Neurobiology Research Unit, Rigshospitalet Copenhagen University Hospital, Blegdamsvej 9, 2100 Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Dag Sehlin
- Rudbeck Laboratory, Department of Public Health and Caring Sciences, University of Uppsala, Dag Hammarskjölds väg 20, 75185 Uppsala, Sweden
| | - Stina Syvänen
- Rudbeck Laboratory, Department of Public Health and Caring Sciences, University of Uppsala, Dag Hammarskjölds väg 20, 75185 Uppsala, Sweden
| | - Matthias M. Herth
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Copenhagen University Hospital, Blegdamsvej 9, 2100 Copenhagen, Denmark
- Correspondence:
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24
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Rofo F, Meier SR, Metzendorf NG, Morrison JI, Petrovic A, Syvänen S, Sehlin D, Hultqvist G. A Brain-Targeting Bispecific-Multivalent Antibody Clears Soluble Amyloid-Beta Aggregates in Alzheimer's Disease Mice. Neurotherapeutics 2022; 19:1588-1602. [PMID: 35939261 PMCID: PMC9606191 DOI: 10.1007/s13311-022-01283-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2022] [Indexed: 12/04/2022] Open
Abstract
Amyloid-β (Aβ) oligomers and protofibrils are suggested to be the most neurotoxic Aβ species in Alzheimer's disease (AD). Hence, antibodies with strong and selective binding to these soluble Aβ aggregates are of therapeutic potential. We have recently introduced HexaRmAb158, a multivalent antibody with additional Aβ-binding sites in the form of single-chain fragment variables (scFv) on the N-terminal ends of Aβ protofibril selective antibody (RmAb158). Due to the additional binding sites and the short distance between them, HexaRmAb158 displayed a slow dissociation from protofibrils and strong binding to oligomers in vitro. In the current study, we aimed at investigating the therapeutic potential of this antibody format in vivo using mouse models of AD. To enhance BBB delivery, the transferrin receptor (TfR) binding moiety (scFv8D3) was added, forming the bispecific-multivalent antibody (HexaRmAb158-scFv8D3). The new antibody displayed a weaker TfR binding compared to the previously developed RmAb158-scFv8D3 and was less efficiently transcytosed in a cell-based BBB model. HexaRmAb158 detected soluble Aβ aggregates derived from brains of tg-ArcSwe and AppNL-G-F mice more efficiently compared to RmAb158. When intravenously injected, HexaRmAb158-scFv8D3 was actively transported over the BBB into the brain in vivo. Brain uptake was marginally lower than that of RmAb158-scFv8D3, but significantly higher than observed for conventional IgG antibodies. Both antibody formats displayed similar brain retention (72 h post injection) and equal capacity in clearing soluble Aβ aggregates in tg-ArcSwe mice. In conclusion, we demonstrate a bispecific-multivalent antibody format capable of passing the BBB and targeting a wide-range of sizes of soluble Aβ aggregates.
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Affiliation(s)
- Fadi Rofo
- Department of Pharmacy, Uppsala University, 75124, Uppsala, Sweden
| | - Silvio R Meier
- Department of Public Health and Caring Sciences, Uppsala University, 75185, Uppsala, Sweden
| | | | - Jamie I Morrison
- Department of Pharmacy, Uppsala University, 75124, Uppsala, Sweden
| | - Alex Petrovic
- Department of Pharmacy, Uppsala University, 75124, Uppsala, Sweden
| | - Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, 75185, Uppsala, Sweden
| | - Dag Sehlin
- Department of Public Health and Caring Sciences, Uppsala University, 75185, Uppsala, Sweden
| | - Greta Hultqvist
- Department of Pharmacy, Uppsala University, 75124, Uppsala, Sweden.
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25
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Prange S, Theis H, Banwinkler M, van Eimeren T. Molecular Imaging in Parkinsonian Disorders—What’s New and Hot? Brain Sci 2022; 12:brainsci12091146. [PMID: 36138882 PMCID: PMC9496752 DOI: 10.3390/brainsci12091146] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 12/02/2022] Open
Abstract
Highlights Abstract Neurodegenerative parkinsonian disorders are characterized by a great diversity of clinical symptoms and underlying neuropathology, yet differential diagnosis during lifetime remains probabilistic. Molecular imaging is a powerful method to detect pathological changes in vivo on a cellular and molecular level with high specificity. Thereby, molecular imaging enables to investigate functional changes and pathological hallmarks in neurodegenerative disorders, thus allowing to better differentiate between different forms of degenerative parkinsonism, improve the accuracy of the clinical diagnosis and disentangle the pathophysiology of disease-related symptoms. The past decade led to significant progress in the field of molecular imaging, including the development of multiple new and promising radioactive tracers for single photon emission computed tomography (SPECT) and positron emission tomography (PET) as well as novel analytical methods. Here, we review the most recent advances in molecular imaging for the diagnosis, prognosis, and mechanistic understanding of parkinsonian disorders. First, advances in imaging of neurotransmission abnormalities, metabolism, synaptic density, inflammation, and pathological protein aggregation are reviewed, highlighting our renewed understanding regarding the multiplicity of neurodegenerative processes involved in parkinsonian disorders. Consequently, we review the role of molecular imaging in the context of disease-modifying interventions to follow neurodegeneration, ensure stratification, and target engagement in clinical trials.
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Affiliation(s)
- Stéphane Prange
- Multimodal Neuroimaging Group, Department of Nuclear Medicine, Faculty of Medicine, University Hospital of Cologne, University of Cologne, 50937 Cologne, Germany
- Institut des Sciences Cognitives Marc Jeannerod, CNRS, UMR 5229, Université de Lyon, 69675 Bron, France
- Correspondence: (S.P.); (T.v.E.); Tel.: +49-221-47882843 (T.v.E.)
| | - Hendrik Theis
- Multimodal Neuroimaging Group, Department of Nuclear Medicine, Faculty of Medicine, University Hospital of Cologne, University of Cologne, 50937 Cologne, Germany
- Department of Neurology, Faculty of Medicine, University Hospital of Cologne, University of Cologne, 50937 Cologne, Germany
| | - Magdalena Banwinkler
- Multimodal Neuroimaging Group, Department of Nuclear Medicine, Faculty of Medicine, University Hospital of Cologne, University of Cologne, 50937 Cologne, Germany
| | - Thilo van Eimeren
- Multimodal Neuroimaging Group, Department of Nuclear Medicine, Faculty of Medicine, University Hospital of Cologne, University of Cologne, 50937 Cologne, Germany
- Department of Neurology, Faculty of Medicine, University Hospital of Cologne, University of Cologne, 50937 Cologne, Germany
- Correspondence: (S.P.); (T.v.E.); Tel.: +49-221-47882843 (T.v.E.)
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26
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Cervenka S, Frick A, Bodén R, Lubberink M. Application of positron emission tomography in psychiatry-methodological developments and future directions. Transl Psychiatry 2022; 12:248. [PMID: 35701411 PMCID: PMC9198063 DOI: 10.1038/s41398-022-01990-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 05/20/2022] [Accepted: 05/25/2022] [Indexed: 11/09/2022] Open
Abstract
Mental disorders represent an increasing source of disability and high costs for societies globally. Molecular imaging techniques such as positron emission tomography (PET) represent powerful tools with the potential to advance knowledge regarding disease mechanisms, allowing the development of new treatment approaches. Thus far, most PET research on pathophysiology in psychiatric disorders has focused on the monoaminergic neurotransmission systems, and although a series of discoveries have been made, the results have not led to any material changes in clinical practice. We outline areas of methodological development that can address some of the important obstacles to fruitful progress. First, we point towards new radioligands and targets that can lead to the identification of processes upstream, or parallel to disturbances in monoaminergic systems. Second, we describe the development of new methods of PET data quantification and PET systems that may facilitate research in psychiatric populations. Third, we review the application of multimodal imaging that can link molecular imaging data to other aspects of brain function, thus deepening our understanding of disease processes. Fourth, we highlight the need to develop imaging study protocols to include longitudinal and interventional paradigms, as well as frameworks to assess dimensional symptoms such that the field can move beyond cross-sectional studies within current diagnostic boundaries. Particular effort should be paid to include also the most severely ill patients. Finally, we discuss the importance of harmonizing data collection and promoting data sharing to reach the desired sample sizes needed to fully capture the phenotype of psychiatric conditions.
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Affiliation(s)
- Simon Cervenka
- Department of Medical Sciences, Psychiatry, Uppsala University, Uppsala, Sweden. .,Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet and Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden.
| | - Andreas Frick
- grid.8993.b0000 0004 1936 9457Department of Medical Sciences, Psychiatry, Uppsala University, Uppsala, Sweden
| | - Robert Bodén
- grid.8993.b0000 0004 1936 9457Department of Medical Sciences, Psychiatry, Uppsala University, Uppsala, Sweden
| | - Mark Lubberink
- grid.8993.b0000 0004 1936 9457Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
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27
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Transferrin Receptor Binding BBB-Shuttle Facilitates Brain Delivery of Anti-Aβ-Affibodies. Pharm Res 2022; 39:1509-1521. [PMID: 35538266 PMCID: PMC9246779 DOI: 10.1007/s11095-022-03282-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 04/29/2022] [Indexed: 12/13/2022]
Abstract
Affibodies targeting amyloid-beta (Aβ) could potentially be used as therapeutic and diagnostic agents in Alzheimer's disease (AD). Affibodies display suitable characteristics for imaging applications such as high stability and a short biological half-life. The aim of this study was to explore brain delivery and retention of Aβ protofibril-targeted affibodies in wild-type (WT) and AD transgenic mice and to evaluate their potential as imaging agents. Two affibodies, Z5 and Z1, were fused with the blood-brain barrier (BBB) shuttle single-chain variable fragment scFv8D3. In vitro binding of 125I-labeled affibodies with and without scFv8D3 was evaluated by ELISA and autoradiography. Brain uptake and retention of the affibodies at 2 h and 24 h post injection was studied ex vivo in WT and transgenic (tg-Swe and tg-ArcSwe) mice. At 2 h post injection, [125I]I-Z5 and [125I]I-Z1 displayed brain concentrations of 0.37 ± 0.09% and 0.46 ± 0.08% ID/g brain, respectively. [125I]I-scFv8D3-Z5 and [125I]I-scFv8D3-Z1 showed increased brain concentrations of 0.53 ± 0.16% and 1.20 ± 0.35%ID/g brain. At 24 h post injection, brain retention of [125I]I-Z1 and [125I]I-Z5 was low, while [125I]I-scFv8D3-Z1 and [125I]I-scFv8D3-Z5 showed moderate brain retention, with a tendency towards higher retention of [125I]I-scFv8D3-Z5 in AD transgenic mice. Nuclear track emulsion autoradiography showed greater parenchymal distribution of [125I]I-scFv8D3-Z5 and [125I]I-scFv8D3-Z1 compared with the affibodies without scFv8D3, but could not confirm specific affibody accumulation around Aβ deposits. Affibody-scFv8D3 fusions displayed increased brain and parenchymal delivery compared with the non-fused affibodies. However, fast brain washout and a suboptimal balance between Aβ and mTfR1 affinity resulted in low intrabrain retention around Aβ deposits.
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28
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Syvänen S, Meier SR, Roshanbin S, Xiong M, Faresjö R, Gustavsson T, Bonvicini G, Schlein E, Aguilar X, Julku U, Eriksson J, Sehlin D. PET Imaging in Preclinical Anti-Aβ Drug Development. Pharm Res 2022; 39:1481-1496. [PMID: 35501533 PMCID: PMC9246809 DOI: 10.1007/s11095-022-03277-z] [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: 03/15/2022] [Accepted: 04/25/2022] [Indexed: 11/21/2022]
Abstract
Positron emission tomography (PET), a medical imaging technique allowing for studies of the living human brain, has gained an important role in clinical trials of novel drugs against Alzheimer’s disease (AD). For example, PET data contributed to the conditional approval in 2021 of aducanumab, an antibody directed towards amyloid-beta (Aβ) aggregates, by showing a dose-dependent reduction in brain amyloid after treatment. In parallel to clinical studies, preclinical studies in animal models of Aβ pathology may also benefit from PET as a tool to detect target engagement and treatment effects of anti-Aβ drug candidates. PET is associated with a high level of translatability between species as similar, non-invasive protocols allow for longitudinal rather than cross-sectional studies and can be used both in a preclinical and clinical setting. This review focuses on the use of preclinical PET imaging in genetically modified animals that express human Aβ, and its present and potential future role in the development of drugs aimed at reducing brain Aβ levels as a therapeutic strategy to halt disease progression in AD.
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Affiliation(s)
- Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, Dag Hammarskjöldsväg 20, 75185, Uppsala, Sweden.
| | - Silvio R Meier
- Department of Public Health and Caring Sciences, Uppsala University, Dag Hammarskjöldsväg 20, 75185, Uppsala, Sweden
| | - Sahar Roshanbin
- Department of Public Health and Caring Sciences, Uppsala University, Dag Hammarskjöldsväg 20, 75185, Uppsala, Sweden
| | - Mengfei Xiong
- Department of Public Health and Caring Sciences, Uppsala University, Dag Hammarskjöldsväg 20, 75185, Uppsala, Sweden
| | - Rebecca Faresjö
- Department of Public Health and Caring Sciences, Uppsala University, Dag Hammarskjöldsväg 20, 75185, Uppsala, Sweden
| | - Tobias Gustavsson
- Department of Public Health and Caring Sciences, Uppsala University, Dag Hammarskjöldsväg 20, 75185, Uppsala, Sweden
| | - Gillian Bonvicini
- Department of Public Health and Caring Sciences, Uppsala University, Dag Hammarskjöldsväg 20, 75185, Uppsala, Sweden.,BioArctic AB, Stockholm, Sweden
| | - Eva Schlein
- Department of Public Health and Caring Sciences, Uppsala University, Dag Hammarskjöldsväg 20, 75185, Uppsala, Sweden
| | - Ximena Aguilar
- Department of Public Health and Caring Sciences, Uppsala University, Dag Hammarskjöldsväg 20, 75185, Uppsala, Sweden
| | - Ulrika Julku
- Department of Public Health and Caring Sciences, Uppsala University, Dag Hammarskjöldsväg 20, 75185, Uppsala, Sweden
| | - Jonas Eriksson
- Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden.,PET Centre, Uppsala University Hospital, Uppsala, Sweden
| | - Dag Sehlin
- Department of Public Health and Caring Sciences, Uppsala University, Dag Hammarskjöldsväg 20, 75185, Uppsala, Sweden
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29
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Alzghool OM, van Dongen G, van de Giessen E, Schoonmade L, Beaino W. α-Synuclein Radiotracer Development and In Vivo Imaging: Recent Advancements and New Perspectives. Mov Disord 2022; 37:936-948. [PMID: 35289424 PMCID: PMC9310945 DOI: 10.1002/mds.28984] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 02/14/2022] [Accepted: 02/21/2022] [Indexed: 12/13/2022] Open
Abstract
α-Synucleinopathies including idiopathic Parkinson's disease, dementia with Lewy bodies and multiple systems atrophy share overlapping symptoms and pathological hallmarks. Selective neurodegeneration and Lewy pathology are the main hallmarks of α-synucleinopathies. Currently, there is no imaging biomarker suitable for a definitive early diagnosis of α-synucleinopathies. Although dopaminergic deficits detected with single-photon emission computed tomography (SPECT) and positron emission tomography (PET) radiotracers can support clinical diagnosis by confirming the presence of dopaminergic neurodegeneration, dopaminergic imaging cannot visualize the preceding disease process, nor distinguish α-synucleinopathies from tauopathies with dopaminergic neurodegeneration, especially at early symptomatic disease stage when clinical presentation is often overlapping. Aggregated α-synuclein (αSyn) could be a suitable imaging biomarker in α-synucleinopathies, because αSyn aggregation and therefore, Lewy pathology is evidently an early driver of α-synucleinopathies pathogenesis. Additionally, several antibodies and small molecule compounds targeting aggregated αSyn are in development for therapy. However, there is no way to directly measure if or how much they lower the levels of aggregated αSyn in the brain. There is clearly a paramount diagnostic and therapeutic unmet medical need. To date, aggregated αSyn and Lewy pathology inclusion bodies cannot be assessed ante-mortem with SPECT or PET imaging because of the suboptimal binding characteristics and/or physicochemical properties of current radiotracers. The aim of this narrative review is to highlight the suitability of aggregated αSyn as an imaging biomarker in α-synucleinopathies, the current limitations with and lessons learned from αSyn radiotracer development, and finally to propose antibody-based ligands for imaging αSyn aggregates as a complementary tool rather than an alternative to small molecule ligands. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson Movement Disorder Society.
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Affiliation(s)
- Obada M Alzghool
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, The Netherlands.,Turku PET Centre, University of Turku, Turku, Finland
| | - Guus van Dongen
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, The Netherlands
| | - Elsmarieke van de Giessen
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, The Netherlands
| | - Linda Schoonmade
- Medical Library, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Wissam Beaino
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, The Netherlands
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30
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Roshanbin S, Xiong M, Hultqvist G, Söderberg L, Zachrisson O, Meier S, Ekmark-Lewén S, Bergström J, Ingelsson M, Sehlin D, Syvänen S. In vivo imaging of alpha-synuclein with antibody-based PET. Neuropharmacology 2022; 208:108985. [PMID: 35149134 DOI: 10.1016/j.neuropharm.2022.108985] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 01/05/2022] [Accepted: 02/02/2022] [Indexed: 12/11/2022]
Abstract
The protein alpha-synuclein (αSYN) plays a central role in synucleinopathies such as Parkinsons's disease (PD) and multiple system atrophy (MSA). Presently, there are no selective αSYN positron emission tomography (PET) radioligands that do not also show affinity to amyloid-beta (Aβ). We have previously shown that radiolabeled antibodies, engineered to enter the brain via the transferrin receptor (TfR), is a promising approach for PET imaging of intrabrain targets. In this study, we used this strategy to visualize αSYN in the living mouse brain. Five bispecific antibodies, binding to both the murine TfR and αSYN were generated and radiolabeled with iodine-125 or iodine-124. All bispecific antibodies bound to αSYN and mTfR before and after radiolabelling in an ELISA assay, and bound to brain sections prepared from αSYN overexpressing mice as well as human PD- and MSA subjects, but not control tissues in autoradiography. Brain concentrations of the bispecific antibodies were between 26-63 times higher than the unmodified IgG format 2 h post-injection, corresponding to about 1.5% of the injected dose per gram brain tissue. Additionally, intrastriatal αSYN fibrils were visualised with PET in an αSYN deposition mouse model with one of the bispecific antibodies, [124I]RmAbSynO2-scFv8D3. However, PET images acquired in αSYN transgenic mice with verified brain pathology injected with [124I]RmAbSynO2-scFv8D3 and [124I]RmAb48-scFv8D3 showed no increase in antibody retention compared to WT mice. Despite successful imaging of deposited extracellular αSYN using a brain-penetrating antibody-based radioligand with no cross-specificity towards Aβ, this proof-of-concept study demonstrates challenges in imaging intracellular αSYN inclusions present in synucleinopathies.
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Affiliation(s)
- Sahar Roshanbin
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden.
| | - Mengfei Xiong
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Greta Hultqvist
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | | | | | - Silvio Meier
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Sara Ekmark-Lewén
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Joakim Bergström
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Martin Ingelsson
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden; Department of Medicine and Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
| | - Dag Sehlin
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
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31
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Tatulian SA. Challenges and hopes for Alzheimer's disease. Drug Discov Today 2022; 27:1027-1043. [PMID: 35121174 DOI: 10.1016/j.drudis.2022.01.016] [Citation(s) in RCA: 86] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 09/01/2021] [Accepted: 01/27/2022] [Indexed: 12/11/2022]
Abstract
Recent drug development efforts targeting Alzheimer's disease (AD) have failed to produce effective disease-modifying agents for many reasons, including the substantial presymptomatic neuronal damage that is caused by the accumulation of the amyloid β (Aβ) peptide and tau protein abnormalities, deleterious adverse effects of drug candidates, and inadequate design of clinical trials. New molecular targets, biomarkers, and diagnostic techniques, as well as alternative nonpharmacological approaches, are sorely needed to detect and treat early pathological events. This article analyzes the successes and debacles of pharmaceutical endeavors to date, and highlights new technologies that may lead to the more effective diagnosis and treatment of the pathologies that underlie AD. The use of focused ultrasound, deep brain stimulation, stem cell therapy, and gene therapy, in parallel with pharmaceuticals and judicious lifestyle adjustments, holds promise for the deceleration, prevention, or cure of AD and other neurodegenerative disorders.
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Affiliation(s)
- Suren A Tatulian
- Department of Physics, College of Sciences, and Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32816, USA.
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32
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Pardridge WM. Kinetics of Blood-Brain Barrier Transport of Monoclonal Antibodies Targeting the Insulin Receptor and the Transferrin Receptor. Pharmaceuticals (Basel) 2021; 15:3. [PMID: 35056060 PMCID: PMC8778919 DOI: 10.3390/ph15010003] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 12/10/2021] [Accepted: 12/18/2021] [Indexed: 12/21/2022] Open
Abstract
Biologic drugs are large molecule pharmaceuticals that do not cross the blood-brain barrier (BBB), which is formed by the brain capillary endothelium. Biologics can be re-engineered for BBB transport as IgG fusion proteins, where the IgG domain is a monoclonal antibody (MAb) that targets an endogenous BBB transporter, such as the insulin receptor (IR) or transferrin receptor (TfR). The IR and TfR at the BBB transport the receptor-specific MAb in parallel with the transport of the endogenous ligand, insulin or transferrin. The kinetics of BBB transport of insulin or transferrin, or an IRMAb or TfRMAb, can be quantified with separate mathematical models. Mathematical models to estimate the half-time of receptor endocytosis, MAb or ligand exocytosis into brain extracellular space, or receptor recycling back to the endothelial luminal membrane were fit to the brain uptake of a TfRMAb or a IRMAb fusion protein in the Rhesus monkey. Model fits to the data also allow for estimates of the rates of association of the MAb in plasma with the IR or TfR that is embedded within the endothelial luminal membrane in vivo. The parameters generated from the model fits can be used to estimate the brain concentration profile of the MAb over time, and this brain exposure is shown to be a function of the rate of clearance of the antibody fusion protein from the plasma compartment.
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Hampel H, Hardy J, Blennow K, Chen C, Perry G, Kim SH, Villemagne VL, Aisen P, Vendruscolo M, Iwatsubo T, Masters CL, Cho M, Lannfelt L, Cummings JL, Vergallo A. The Amyloid-β Pathway in Alzheimer's Disease. Mol Psychiatry 2021; 26:5481-5503. [PMID: 34456336 PMCID: PMC8758495 DOI: 10.1038/s41380-021-01249-0] [Citation(s) in RCA: 498] [Impact Index Per Article: 166.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 07/19/2021] [Accepted: 07/28/2021] [Indexed: 02/06/2023]
Abstract
Breakthroughs in molecular medicine have positioned the amyloid-β (Aβ) pathway at the center of Alzheimer's disease (AD) pathophysiology. While the detailed molecular mechanisms of the pathway and the spatial-temporal dynamics leading to synaptic failure, neurodegeneration, and clinical onset are still under intense investigation, the established biochemical alterations of the Aβ cycle remain the core biological hallmark of AD and are promising targets for the development of disease-modifying therapies. Here, we systematically review and update the vast state-of-the-art literature of Aβ science with evidence from basic research studies to human genetic and multi-modal biomarker investigations, which supports a crucial role of Aβ pathway dyshomeostasis in AD pathophysiological dynamics. We discuss the evidence highlighting a differentiated interaction of distinct Aβ species with other AD-related biological mechanisms, such as tau-mediated, neuroimmune and inflammatory changes, as well as a neurochemical imbalance. Through the lens of the latest development of multimodal in vivo biomarkers of AD, this cross-disciplinary review examines the compelling hypothesis- and data-driven rationale for Aβ-targeting therapeutic strategies in development for the early treatment of AD.
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Affiliation(s)
- Harald Hampel
- Eisai Inc., Neurology Business Group, Woodcliff Lake, NJ, USA.
| | - John Hardy
- UK Dementia Research Institute at UCL and Department of Neurodegenerative Disease, UCL Institute of Neurology, University College London, London, UK
| | - Kaj Blennow
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Christopher Chen
- Memory Aging and Cognition Centre, Departments of Pharmacology and Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - George Perry
- Department of Biology and Neurosciences Institute, University of Texas at San Antonio (UTSA), San Antonio, TX, USA
| | - Seung Hyun Kim
- Department of Neurology, College of Medicine, Hanyang University, Seoul, Republic of Korea; Cell Therapy Center, Hanyang University Hospital, Seoul, Republic of Korea
| | - Victor L Villemagne
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia
| | - Paul Aisen
- USC Alzheimer's Therapeutic Research Institute, San Diego, CA, USA
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Takeshi Iwatsubo
- Department of Neuropathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Colin L Masters
- Laureate Professor of Dementia Research, Florey Institute and The University of Melbourne, Parkville, VIC, Australia
| | - Min Cho
- Eisai Inc., Neurology Business Group, Woodcliff Lake, NJ, USA
| | - Lars Lannfelt
- Uppsala University, Department of of Public Health/Geriatrics, Uppsala, Sweden
- BioArctic AB, Stockholm, Sweden
| | - Jeffrey L Cummings
- Chambers-Grundy Center for Transformative Neuroscience, Department of Brain Health, School of Integrated Health Sciences, University of Nevada Las Vegas (UNLV), Las Vegas, NV, USA
| | - Andrea Vergallo
- Eisai Inc., Neurology Business Group, Woodcliff Lake, NJ, USA.
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34
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Bidesi NSR, Vang Andersen I, Windhorst AD, Shalgunov V, Herth MM. The role of neuroimaging in Parkinson's disease. J Neurochem 2021; 159:660-689. [PMID: 34532856 PMCID: PMC9291628 DOI: 10.1111/jnc.15516] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 09/09/2021] [Accepted: 09/10/2021] [Indexed: 11/29/2022]
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder that affects millions of people worldwide. Two hallmarks of PD are the accumulation of alpha-synuclein and the loss of dopaminergic neurons in the brain. There is no cure for PD, and all existing treatments focus on alleviating the symptoms. PD diagnosis is also based on the symptoms, such as abnormalities of movement, mood, and cognition observed in the patients. Molecular imaging methods such as magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT), and positron emission tomography (PET) can detect objective alterations in the neurochemical machinery of the brain and help diagnose and study neurodegenerative diseases. This review addresses the application of functional MRI, PET, and SPECT in PD patients. We provide an overview of the imaging targets, discuss the rationale behind target selection, the agents (tracers) with which the imaging can be performed, and the main findings regarding each target's state in PD. Molecular imaging has proven itself effective in supporting clinical diagnosis of PD and has helped reveal that PD is a heterogeneous disorder, which has important implications for the development of future therapies. However, the application of molecular imaging for early diagnosis of PD or for differentiation between PD and atypical parkinsonisms has remained challenging. The final section of the review is dedicated to new imaging targets with which one can detect the PD-related pathological changes upstream from dopaminergic degeneration. The foremost of those targets is alpha-synuclein. We discuss the progress of tracer development achieved so far and challenges on the path toward alpha-synuclein imaging in humans.
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Affiliation(s)
- Natasha S R Bidesi
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Ida Vang Andersen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Albert D Windhorst
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Vladimir Shalgunov
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Matthias M Herth
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen, Denmark
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35
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Gkanatsiou E, Nilsson J, Toomey CE, Vrillon A, Kvartsberg H, Portelius E, Zetterberg H, Blennow K, Brinkmalm A, Lashley T, Brinkmalm G. Amyloid pathology and synaptic loss in pathological aging. J Neurochem 2021; 159:258-272. [PMID: 34473357 DOI: 10.1111/jnc.15487] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 07/24/2021] [Accepted: 07/26/2021] [Indexed: 01/04/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive memory dysfunction and cognitive decline. Pathological aging (PA) describes patients who are amyloid-positive but cognitively unimpaired at time of death. Both AD and PA contain amyloid plaques dominated by amyloid β (Aβ) peptides. In this study, we investigated and compared synaptic protein levels, amyloid plaque load, and Aβ peptide patterns between AD and PA. Two cohorts of post-mortem brain tissue were investigated. In the first, consisting of controls, PA, AD, and familial AD (FAD) individuals, synaptic proteins extracted with tris(hydroxymethyl)aminomethane-buffered saline (TBS) were analyzed. In the second, consisting of tissue from AD and PA patients from three different regions (occipital lobe, frontal lobe, and cerebellum), a two-step extraction was performed. Five synaptic proteins were extracted using TBS, and from the remaining portion Aβ peptides were extracted using formic acid. Subsequently, immunoprecipitation with several antibodies targeting different proteins/peptides was performed for both fractions, which were subsequently analyzed by mass spectrometry. The levels of synaptic proteins were lower in AD (and FAD) compared with PA (and controls), confirming synaptic loss in AD patients. The amyloid plaque load was increased in AD compared with PA, and the relative amount of Aβ40 was higher in AD while for Aβ42 it was higher in PA. In AD loss of synaptic function was associated with increased plaque load and increased amounts of Aβ40 compared with PA cases, suggesting that synaptic function is preserved in PA cases even in the presence of Aβ.
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Affiliation(s)
- Eleni Gkanatsiou
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Johanna Nilsson
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Christina E Toomey
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK.,UK Dementia Research Institute at UCL, London, UK.,Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
| | - Agathe Vrillon
- Center of Cognitive Neurology, Lariboisière Fernand-Widal Hospital, APHP, University of Paris Diderot, Paris, France
| | - Hlin Kvartsberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Erik Portelius
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.,UK Dementia Research Institute at UCL, London, UK.,Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK.,Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Ann Brinkmalm
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Tammaryn Lashley
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK.,Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
| | - Gunnar Brinkmalm
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
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36
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Alpha-Synuclein PET Tracer Development-An Overview about Current Efforts. Pharmaceuticals (Basel) 2021; 14:ph14090847. [PMID: 34577548 PMCID: PMC8466155 DOI: 10.3390/ph14090847] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 12/18/2022] Open
Abstract
Neurodegenerative diseases such as Parkinson’s disease (PD) are manifested by inclusion bodies of alpha-synuclein (α-syn) also called α-synucleinopathies. Detection of these inclusions is thus far only possible by histological examination of postmortem brain tissue. The possibility of non-invasively detecting α-syn will therefore provide valuable insights into the disease progression of α-synucleinopathies. In particular, α-syn imaging can quantify changes in monomeric, oligomeric, and fibrillic α-syn over time and improve early diagnosis of various α-synucleinopathies or monitor treatment progress. Positron emission tomography (PET) is a non-invasive in vivo imaging technique that can quantify target expression and drug occupancies when a suitable tracer exists. As such, novel α-syn PET tracers are highly sought after. The development of an α-syn PET tracer faces several challenges. For example, the low abundance of α-syn within the brain necessitates the development of a high-affinity ligand. Moreover, α-syn depositions are, in contrast to amyloid proteins, predominantly localized intracellularly, limiting their accessibility. Furthermore, another challenge is the ligand selectivity over structurally similar amyloids such as amyloid-beta or tau, which are often co-localized with α-syn pathology. The lack of a defined crystal structure of α-syn has also hindered rational drug and tracer design efforts. Our objective for this review is to provide a comprehensive overview of current efforts in the development of selective α-syn PET tracers.
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37
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Bolcaen J, Kleynhans J, Nair S, Verhoeven J, Goethals I, Sathekge M, Vandevoorde C, Ebenhan T. A perspective on the radiopharmaceutical requirements for imaging and therapy of glioblastoma. Theranostics 2021; 11:7911-7947. [PMID: 34335972 PMCID: PMC8315062 DOI: 10.7150/thno.56639] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/29/2021] [Indexed: 11/26/2022] Open
Abstract
Despite numerous clinical trials and pre-clinical developments, the treatment of glioblastoma (GB) remains a challenge. The current survival rate of GB averages one year, even with an optimal standard of care. However, the future promises efficient patient-tailored treatments, including targeted radionuclide therapy (TRT). Advances in radiopharmaceutical development have unlocked the possibility to assess disease at the molecular level allowing individual diagnosis. This leads to the possibility of choosing a tailored, targeted approach for therapeutic modalities. Therapeutic modalities based on radiopharmaceuticals are an exciting development with great potential to promote a personalised approach to medicine. However, an effective targeted radionuclide therapy (TRT) for the treatment of GB entails caveats and requisites. This review provides an overview of existing nuclear imaging and TRT strategies for GB. A critical discussion of the optimal characteristics for new GB targeting therapeutic radiopharmaceuticals and clinical indications are provided. Considerations for target selection are discussed, i.e. specific presence of the target, expression level and pharmacological access to the target, with particular attention to blood-brain barrier crossing. An overview of the most promising radionuclides is given along with a validation of the relevant radiopharmaceuticals and theranostic agents (based on small molecules, peptides and monoclonal antibodies). Moreover, toxicity issues and safety pharmacology aspects will be presented, both in general and for the brain in particular.
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Affiliation(s)
- Julie Bolcaen
- Radiobiology, Radiation Biophysics Division, Nuclear Medicine Department, iThemba LABS, Cape Town, South Africa
| | - Janke Kleynhans
- Nuclear Medicine Research Infrastructure NPC, Pretoria, South Africa
- Nuclear Medicine Department, University of Pretoria and Steve Biko Academic Hospital, Pretoria, South Africa
| | - Shankari Nair
- Radiobiology, Radiation Biophysics Division, Nuclear Medicine Department, iThemba LABS, Cape Town, South Africa
| | | | - Ingeborg Goethals
- Ghent University Hospital, Department of Nuclear Medicine, Ghent, Belgium
| | - Mike Sathekge
- Nuclear Medicine Research Infrastructure NPC, Pretoria, South Africa
- Nuclear Medicine Department, University of Pretoria and Steve Biko Academic Hospital, Pretoria, South Africa
| | - Charlot Vandevoorde
- Radiobiology, Radiation Biophysics Division, Nuclear Medicine Department, iThemba LABS, Cape Town, South Africa
| | - Thomas Ebenhan
- Nuclear Medicine Research Infrastructure NPC, Pretoria, South Africa
- Nuclear Medicine Department, University of Pretoria, Pretoria, South Africa
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38
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Kouhi A, Pachipulusu V, Kapenstein T, Hu P, Epstein AL, Khawli LA. Brain Disposition of Antibody-Based Therapeutics: Dogma, Approaches and Perspectives. Int J Mol Sci 2021; 22:ijms22126442. [PMID: 34208575 PMCID: PMC8235515 DOI: 10.3390/ijms22126442] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/10/2021] [Accepted: 06/11/2021] [Indexed: 12/12/2022] Open
Abstract
Due to their high specificity, monoclonal antibodies have been widely investigated for their application in drug delivery to the central nervous system (CNS) for the treatment of neurological diseases such as stroke, Alzheimer’s, and Parkinson’s disease. Research in the past few decades has revealed that one of the biggest challenges in the development of antibodies for drug delivery to the CNS is the presence of blood–brain barrier (BBB), which acts to restrict drug delivery and contributes to the limited uptake (0.1–0.2% of injected dose) of circulating antibodies into the brain. This article reviews the various methods currently used for antibody delivery to the CNS at the preclinical stage of development and the underlying mechanisms of BBB penetration. It also describes efforts to improve or modulate the physicochemical and biochemical properties of antibodies (e.g., charge, Fc receptor binding affinity, and target affinity), to adapt their pharmacokinetics (PK), and to influence their distribution and disposition into the brain. Finally, a distinction is made between approaches that seek to modify BBB permeability and those that use a physiological approach or antibody engineering to increase uptake in the CNS. Although there are currently inherent difficulties in developing safe and efficacious antibodies that will cross the BBB, the future prospects of brain-targeted delivery of antibody-based agents are believed to be excellent.
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Meier SR, Sehlin D, Roshanbin S, Lim Falk V, Saito T, Saido TC, Neumann U, Rokka J, Eriksson J, Syvanen S. 11C-PIB and 124I-antibody PET provide differing estimates of brain amyloid-beta after therapeutic intervention. J Nucl Med 2021; 63:302-309. [PMID: 34088777 PMCID: PMC8805773 DOI: 10.2967/jnumed.121.262083] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 05/05/2021] [Indexed: 11/16/2022] Open
Abstract
PET imaging of amyloid-β (Aβ) has become an important component of Alzheimer disease diagnosis. 11C-Pittsburgh compound B (11C-PiB) and analogs bind to fibrillar Aβ. However, levels of nonfibrillar, soluble, aggregates of Aβ appear more dynamic during disease progression and more affected by Aβ-reducing treatments. The aim of this study was to compare an antibody-based PET ligand targeting nonfibrillar Aβ with 11C-PiB after β-secretase (BACE-1) inhibition in 2 Alzheimer disease mouse models at an advanced stage of Aβ pathology. Methods: Transgenic ArcSwe mice (16 mo old) were treated with the BACE-1 inhibitor NB-360 for 2 mo, whereas another group was kept as controls. A third group was analyzed at the age of 16 mo as a baseline. Mice were PET-scanned with 11C-PiB to measure Aβ plaque load followed by a scan with the bispecific radioligand 124I-RmAb158-scFv8D3 to investigate nonfibrillar aggregates of Aβ. The same study design was then applied to another mouse model, AppNL-G-F. In this case, NB-360 treatment was initiated at the age of 8 mo and animals were scanned with 11C-PiB-PET and 125I-RmAb158-scFv8D3 SPECT. Brain tissue was isolated after scanning, and Aβ levels were assessed. Results:124I-RmAb158-scFv8D3 concentrations measured with PET in hippocampus and thalamus of NB-360–treated ArcSwe mice were similar to those observed in baseline animals and significantly lower than concentrations observed in same-age untreated controls. Reduced 125I-RmAb158-scFv8D3 retention was also observed with SPECT in hippocampus, cortex, and cerebellum of NB-360–treated AppNL-G-F mice. Radioligand in vivo concentrations corresponded to postmortem brain tissue analysis of soluble Aβ aggregates. For both models, mice treated with NB-360 did not display a reduced 11C-PiB signal compared with untreated controls, and further, both NB-360 and control mice tended, although not reaching significance, to show higher 11C-PiB signal than the baseline groups. Conclusion: This study demonstrated the ability of an antibody-based radioligand to detect changes in brain Aβ levels after anti-Aβ therapy in ArcSwe and AppNL-G-F mice with pronounced Aβ pathology. In contrast, the decreased Aβ levels could not be quantified with 11C-PiB PET, suggesting that these ligands detect different pools of Aβ.
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Faresjö R, Bonvicini G, Fang XT, Aguilar X, Sehlin D, Syvänen S. Brain pharmacokinetics of two BBB penetrating bispecific antibodies of different size. Fluids Barriers CNS 2021; 18:26. [PMID: 34078410 PMCID: PMC8170802 DOI: 10.1186/s12987-021-00257-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/07/2021] [Indexed: 11/16/2022] Open
Abstract
Background Transferrin receptor (TfR1) mediated enhanced brain delivery of antibodies have been studied extensively in preclinical settings. However, the brain pharmacokinetics, i.e. brain entry, distribution and elimination are still not fully understood for this class of antibodies. The overall aim of the study was to compare the brain pharmacokinetics of two BBB-penetrating bispecific antibodies of different size (210 vs 58 kDa). Specifically, we wanted to investigate if the faster systemic clearance of the smaller non-IgG antibody di-scFv3D6-8D3, in comparison with the IgG-based bispecific antibody mAb3D6-scFv8D3, was also reflected in the brain. Methods Wild-type (C57/Bl6) mice were injected with 125I-iodinated ([125I]) mAb3D6-scFv8D3 (n = 46) or [125I]di-scFv3D6-8D3 (n = 32) and euthanized 2, 4, 6, 8, 10, 12, 16, or 24 h post injection. Ex vivo radioactivity in whole blood, peripheral organs and brain was measured by γ-counting. Ex vivo autoradiography and nuclear track emulsion were performed on brain sections to investigate brain and parenchymal distribution. Capillary depletion was carried out at 2, 6, and 24 h after injection of [125I]mAb3D6-scFv8D3 (n = 12) or [125I]di-scFv3D6-8D3 (n = 12), to estimate the relative levels of radiolabelled antibody in brain capillaries versus brain parenchyma. In vitro binding kinetics for [125I]mAb3D6-scFv8D3 or [125I]di-scFv3D6-8D3 to murine TfR were determined by LigandTracer. Results [125I]di-scFv3D6-8D3 showed faster elimination from blood, lower brain Cmax, and Tmax, a larger parenchymal-to-capillary concentration ratio, and a net elimination from brain at an earlier time point after injection compared with the larger [125I]mAb3D6-scFv8D3. However, the elimination rate from brain did not differ between the antibodies. The study also indicated that [125I]di-scFv3D6-8D3 displayed lower avidity than [125I]mAb3D6-scFv8D3 towards TfR1 in vitro and potentially in vivo, at least at the BBB. Conclusion A smaller size and lower TfR1 avidity are likely important for fast parenchymal delivery, while elimination of brain-associated bispecific antibodies may not be dependent on these characteristics. Supplementary Information The online version contains supplementary material available at 10.1186/s12987-021-00257-0.
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Affiliation(s)
- Rebecca Faresjö
- Department of Public Healt and Caring Sciences, Uppsala University, Rudbeck Laboratory, Dag Hammarskjölds väg 20, 751 85, Uppsala, Sweden
| | - Gillian Bonvicini
- Department of Public Healt and Caring Sciences, Uppsala University, Rudbeck Laboratory, Dag Hammarskjölds väg 20, 751 85, Uppsala, Sweden.,BioArctic AB, Warfvinges väg 35, 112 51, Stockholm, Sweden
| | - Xiaotian T Fang
- Department of Radiology and Biomedical Imaging, Yale University, Yale PET Center, 801 Howard Avenue, New Haven, CT, 06520, USA
| | - Ximena Aguilar
- Department of Public Healt and Caring Sciences, Uppsala University, Rudbeck Laboratory, Dag Hammarskjölds väg 20, 751 85, Uppsala, Sweden
| | - Dag Sehlin
- Department of Public Healt and Caring Sciences, Uppsala University, Rudbeck Laboratory, Dag Hammarskjölds väg 20, 751 85, Uppsala, Sweden
| | - Stina Syvänen
- Department of Public Healt and Caring Sciences, Uppsala University, Rudbeck Laboratory, Dag Hammarskjölds väg 20, 751 85, Uppsala, Sweden.
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Du J, Cherry S. A high resolution and high detection efficiency depth-encoding detector for brain positron emission tomography based on a 0.75 mm pitch scintillator array. JOURNAL OF INSTRUMENTATION : AN IOP AND SISSA JOURNAL 2021; 16:P05015. [PMID: 34925535 PMCID: PMC8681625 DOI: 10.1088/1748-0221/16/05/p05015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The quantitative accuracy and precision of brain positron emission tomography (PET) studies can be considerably improved using dedicated brain PET scanners with a uniform high resolution and a high sensitivity across the brain volume. One approach to building such a system is to construct the PET scanner using depth-of-interaction (DOI) encoding detectors with finely segmented and thick crystal arrays. In this paper, the performance of a DOI PET detector based on two 16 × 16 arrays of 2 × 2 mm2 SiPMs coupled to both ends of a 44 × 44 array of 0.69 × 0.69 × 30 mm3 polished LYSO crystals was evaluated at different temperatures (-9°C, 0°C, 10°C, and 20°C) for brain PET applications. The pitch size of the LYSO array is 0.75 mm. The flood histograms show that all the crystal elements in the LYSO array can be resolved except some edge crystals, due to the limited light sharing. The average energy resolution, average DOI resolution, and average timing resolution across crystal elements are 21.1 ± 3.0%, 3.47 ± 0.17 mm, and 1.38 ± 0.09 ns, respectively, which were obtained at a bias voltage of 56.5 V and a temperature of 0°C.
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Affiliation(s)
- J. Du
- Department of Biomedical Engineering, University of California at Davis, Davis, California 95616, U.S.A
| | - S.R. Cherry
- Department of Biomedical Engineering, University of California at Davis, Davis, California 95616, U.S.A
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Pinpointing Brain TREM2 Levels in Two Mouse Models of Alzheimer's Disease. Mol Imaging Biol 2021; 23:665-675. [PMID: 33620643 PMCID: PMC8410720 DOI: 10.1007/s11307-021-01591-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 01/11/2021] [Accepted: 02/11/2021] [Indexed: 11/01/2022]
Abstract
PURPOSE The triggering receptor expressed on myeloid cells 2 (TREM2) is expressed by brain microglia. Microglial activation, as observed in Alzheimer's disease (AD) as well as in transgenic mice expressing human amyloid-beta, appears to increase soluble TREM2 (sTREM2) levels in CSF and brain. In this study, we used two different transgenic mouse models of AD pathology and investigated the potential of TREM2 to serve as an in vivo biomarker for microglial activation in AD. PROCEDURES We designed and generated a bispecific antibody based on the TREM2-specific monoclonal antibody mAb1729, fused to a single-chain variable fragment of the transferrin receptor binding antibody 8D3. The 8D3-moiety enabled transcytosis of the whole bispecific antibody across the blood-brain barrier. The bispecific antibody was radiolabeled with I-125 (ex vivo) or I-124 (PET) and administered to transgenic AD and wild-type (WT) control mice. Radioligand retention in the brain of transgenic animals was compared to WT mice by isolation of brain tissue at 24 h or 72 h, or with in vivo PET at 24 h, 48 h, and 72 h. Intrabrain distribution of radiolabeled mAb1729-scFv8D3CL was further studied by autoradiography, while ELISA was used to determine TREM2 brain concentrations. RESULTS Transgenic animals displayed higher total exposure, calculated as the AUC based on SUV determined at 24h, 48h, and 72h post injection, of PET radioligand [124I]mAb1729-scFv8D3CL than WT mice. However, differences were not evident in single time point PET images or SUVs. Ex vivo autoradiography confirmed higher radioligand concentrations in cortex and thalamus in transgenic mice compared to WT, and TREM2 levels in brain homogenates were considerably higher in transgenic mice compared to WT. CONCLUSION Antibody-based radioligands, engineered to enter the brain, may serve as PET radioligands to follow changes of TREM2 in vivo, but antibody formats with faster systemic clearance to increase the specific signal in relation to that from blood in combination with antibodies showing higher affinity for TREM2 must be developed to further progress this technique for in vivo use.
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Kulenkampff K, Wolf Perez AM, Sormanni P, Habchi J, Vendruscolo M. Quantifying misfolded protein oligomers as drug targets and biomarkers in Alzheimer and Parkinson diseases. Nat Rev Chem 2021; 5:277-294. [PMID: 37117282 DOI: 10.1038/s41570-021-00254-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2021] [Indexed: 02/06/2023]
Abstract
Protein misfolding and aggregation are characteristic of a wide range of neurodegenerative disorders, including Alzheimer and Parkinson diseases. A hallmark of these diseases is the aggregation of otherwise soluble and functional proteins into amyloid aggregates. Although for many decades such amyloid deposits have been thought to be responsible for disease progression, it is now increasingly recognized that the misfolded protein oligomers formed during aggregation are, instead, the main agents causing pathological processes. These oligomers are transient and heterogeneous, which makes it difficult to detect and quantify them, generating confusion about their exact role in disease. The lack of suitable methods to address these challenges has hampered efforts to investigate the molecular mechanisms of oligomer toxicity and to develop oligomer-based diagnostic and therapeutic tools to combat protein misfolding diseases. In this Review, we describe methods to quantify misfolded protein oligomers, with particular emphasis on diagnostic applications as disease biomarkers and on therapeutic applications as target biomarkers. The development of these methods is ongoing, and we discuss the challenges that remain to be addressed to establish measurement tools capable of overcoming existing limitations and to meet present needs.
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Synthesis and pharmacokinetic characterisation of a fluorine-18 labelled brain shuttle peptide fusion dimeric affibody. Sci Rep 2021; 11:2588. [PMID: 33510301 PMCID: PMC7844286 DOI: 10.1038/s41598-021-82037-2] [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: 10/02/2020] [Accepted: 01/14/2021] [Indexed: 11/08/2022] Open
Abstract
Brain positron emission tomography (PET) imaging with radiolabelled proteins is an emerging concept that potentially enables visualization of unique molecular targets in the brain. However, the pharmacokinetics and protein radiolabelling methods remain challenging. Here, we report the performance of an engineered, blood-brain barrier (BBB)-permeable affibody molecule that exhibits rapid clearance from the brain, which was radiolabelled using a unique fluorine-18 labelling method, a cell-free protein radiosynthesis (CFPRS) system. AS69, a small (14 kDa) dimeric affibody molecule that binds to the monomeric and oligomeric states of α-synuclein, was newly designed for brain delivery with an apolipoprotein E (ApoE)-derived brain shuttle peptide as AS69-ApoE (22 kDa). The radiolabelled products 18F-AS69 and 18F-AS69-ApoE were successfully synthesised using the CFPRS system. Notably, 18F-AS69-ApoE showed higher BBB permeability than 18F-AS69 in an ex vivo study at 10 and 30 min post injection and was partially cleared from the brain at 120 min post injection. These results suggest that small, a brain shuttle peptide-fused fluorine-18 labelled protein binders can potentially be utilised for brain molecular imaging.
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45
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Rofo F, Ugur Yilmaz C, Metzendorf N, Gustavsson T, Beretta C, Erlandsson A, Sehlin D, Syvänen S, Nilsson P, Hultqvist G. Enhanced neprilysin-mediated degradation of hippocampal Aβ42 with a somatostatin peptide that enters the brain. Am J Cancer Res 2021; 11:789-804. [PMID: 33391505 PMCID: PMC7738863 DOI: 10.7150/thno.50263] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 10/13/2020] [Indexed: 12/21/2022] Open
Abstract
Background: Aggregation of the amyloid-beta (Aβ) peptide is one of the main neuropathological events in Alzheimer's disease (AD). Neprilysin is the major enzyme degrading Aβ, with its activity enhanced by the neuropeptide somatostatin (SST). SST levels are decreased in the brains of AD patients. The poor delivery of SST over the blood-brain barrier (BBB) and its extremely short half-life of only 3 min limit its therapeutic significance. Methods: We recombinantly fused SST to a BBB transporter binding to the transferrin receptor. Using primary neuronal cultures and neuroblastoma cell lines, the ability of the formed fusion protein to activate neprilysin was studied. SST-scFv8D3 was administered to mice overexpressing the Aβ-precursor protein (AβPP) with the Swedish mutation (APPswe) as a single injection or as a course of three injections over a 72 h period. Levels of neprilysin and Aβ were quantified using an Enzyme-linked immunosorbent assay (ELISA). Distribution of SST-scFv8D3 in the brain, blood and peripheral organs was studied by radiolabeling with iodine-125. Results: The construct, SST-scFv8D3, exhibited 120 times longer half-life than SST alone, reached the brain in high amounts when injected intravenously and significantly increased the brain concentration of neprilysin in APPswe mice. A significant decrease in the levels of membrane-bound Aβ42 was detected in the hippocampus and the adjacent cortical area after only three injections. Conclusion: With intravenous injections of our BBB permeable SST peptide, we were able to significantly increase the levels neprilysin, an effect that was followed by a significant and selective degradation of membrane-bound Aβ42 in the hippocampus. Being that membrane-bound Aβ triggers neuronal toxicity and the hippocampus is the central brain area in the progression of AD, the study has illuminated a new potential treatment paradigm with a promising safety profile targeting only the disease affected areas.
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46
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Syvänen S, Fang XT, Faresjö R, Rokka J, Lannfelt L, Olberg DE, Eriksson J, Sehlin D. Fluorine-18-Labeled Antibody Ligands for PET Imaging of Amyloid-β in Brain. ACS Chem Neurosci 2020; 11:4460-4468. [PMID: 33236886 PMCID: PMC7747219 DOI: 10.1021/acschemneuro.0c00652] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Antibodies are attractive as radioligands due to their outstanding specificity and high affinity, but their inability to cross the blood-brain barrier (BBB) limits their use for CNS targets. To enhance brain distribution, amyloid-β (Aβ) antibodies were fused to a transferrin receptor (TfR) antibody fragment, enabling receptor mediated transport across the BBB. The aim of this study was to label these bispecific antibodies with fluorine-18 and use them for Aβ PET imaging. Bispecific antibody ligands RmAb158-scFv8D3 and Tribody A2, both targeting Aβ and TfR, were functionalized with trans-cyclooctene (TCO) groups and conjugated with 18F-labeled tetrazines through an inverse electron demand Diels-Alder reaction performed at ambient temperature. 18F-labeling did not affect antibody binding in vitro, and initial brain uptake was high. Conjugates with the first tetrazine variant ([18F]T1) displayed high uptake in bone, indicating extensive defluorination, a problem that was resolved with the second and third tetrazine variants ([18F]T2 and [18F]T3). Although the antibody ligands' half-life in blood was too long to optimally match the physical half-life of fluorine-18 (t1/2 = 110 min), [18F]T3-Tribody A2 PET seemed to discriminate transgenic mice (tg-ArcSwe) with Aβ deposits from wild-type mice 12 h after injection. This study demonstrates that 18F-labeling of bispecific, brain penetrating antibodies is feasible and, with further optimization, could be used for CNS PET imaging.
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Affiliation(s)
- Stina Syvänen
- Department of Public Health and Caring Sciences, Rudbeck Laboratory, Uppsala University, Uppsala 751 85, Sweden
| | - Xiaotian T Fang
- Department of Public Health and Caring Sciences, Rudbeck Laboratory, Uppsala University, Uppsala 751 85, Sweden
- Department of Radiology and Biomedical Imaging, Yale University, Yale PET Center, New Haven 06520, Connecticut United States
| | - Rebecca Faresjö
- Department of Public Health and Caring Sciences, Rudbeck Laboratory, Uppsala University, Uppsala 751 85, Sweden
| | - Johanna Rokka
- Department of Public Health and Caring Sciences, Rudbeck Laboratory, Uppsala University, Uppsala 751 85, Sweden
| | - Lars Lannfelt
- Department of Public Health and Caring Sciences, Rudbeck Laboratory, Uppsala University, Uppsala 751 85, Sweden
- BioArctic AB, Stockholm 112 51, Sweden
| | - Dag E Olberg
- Norsk medisinsk syklotronsenter AS, Oslo Postboks 4950, Norway
- Department of Pharmacy, University of Oslo, Oslo 0424, Norway
| | - Jonas Eriksson
- Department of Medicinal Chemistry, Division of Organic Pharmaceutical Chemistry, Uppsala University, Uppsala 751 23, Sweden
- PET Centre, Uppsala University Hospital, Uppsala 751 85, Sweden
| | - Dag Sehlin
- Department of Public Health and Caring Sciences, Rudbeck Laboratory, Uppsala University, Uppsala 751 85, Sweden
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Sehlin D, Stocki P, Gustavsson T, Hultqvist G, Walsh FS, Rutkowski JL, Syvänen S. Brain delivery of biologics using a cross‐species reactive transferrin receptor 1 VNAR shuttle. FASEB J 2020; 34:13272-13283. [DOI: 10.1096/fj.202000610rr] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 07/09/2020] [Accepted: 07/16/2020] [Indexed: 11/11/2022]
Affiliation(s)
- Dag Sehlin
- Department of Public Health and Caring Sciences/Geriatrics Uppsala University Uppsala Sweden
| | - Pawel Stocki
- Ossianix, Inc. Stevenage UK
- Ossianix, Inc. Philadelphia PA USA
| | - Tobias Gustavsson
- Department of Public Health and Caring Sciences/Geriatrics Uppsala University Uppsala Sweden
| | - Greta Hultqvist
- Department of Pharmaceutical Biosciences Uppsala University Uppsala Sweden
| | - Frank S. Walsh
- Ossianix, Inc. Stevenage UK
- Ossianix, Inc. Philadelphia PA USA
| | | | - Stina Syvänen
- Department of Public Health and Caring Sciences/Geriatrics Uppsala University Uppsala Sweden
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Wei W, Rosenkrans ZT, Liu J, Huang G, Luo QY, Cai W. ImmunoPET: Concept, Design, and Applications. Chem Rev 2020; 120:3787-3851. [PMID: 32202104 DOI: 10.1021/acs.chemrev.9b00738] [Citation(s) in RCA: 242] [Impact Index Per Article: 60.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Immuno-positron emission tomography (immunoPET) is a paradigm-shifting molecular imaging modality combining the superior targeting specificity of monoclonal antibody (mAb) and the inherent sensitivity of PET technique. A variety of radionuclides and mAbs have been exploited to develop immunoPET probes, which has been driven by the development and optimization of radiochemistry and conjugation strategies. In addition, tumor-targeting vectors with a short circulation time (e.g., Nanobody) or with an enhanced binding affinity (e.g., bispecific antibody) are being used to design novel immunoPET probes. Accordingly, several immunoPET probes, such as 89Zr-Df-pertuzumab and 89Zr-atezolizumab, have been successfully translated for clinical use. By noninvasively and dynamically revealing the expression of heterogeneous tumor antigens, immunoPET imaging is gradually changing the theranostic landscape of several types of malignancies. ImmunoPET is the method of choice for imaging specific tumor markers, immune cells, immune checkpoints, and inflammatory processes. Furthermore, the integration of immunoPET imaging in antibody drug development is of substantial significance because it provides pivotal information regarding antibody targeting abilities and distribution profiles. Herein, we present the latest immunoPET imaging strategies and their preclinical and clinical applications. We also emphasize current conjugation strategies that can be leveraged to develop next-generation immunoPET probes. Lastly, we discuss practical considerations to tune the development and translation of immunoPET imaging strategies.
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Affiliation(s)
- Weijun Wei
- Department of Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China.,Departments of Radiology and Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Room 7137, Madison, Wisconsin 53705, United States
| | - Zachary T Rosenkrans
- Department of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Jianjun Liu
- Department of Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Gang Huang
- Department of Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China.,Shanghai Key Laboratory of Molecular Imaging, Shanghai University of Medicine and Health Sciences, Shanghai 201318, China
| | - Quan-Yong Luo
- Department of Nuclear Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Weibo Cai
- Departments of Radiology and Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Room 7137, Madison, Wisconsin 53705, United States.,Department of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States.,University of Wisconsin Carbone Cancer Center, Madison, Wisconsin 53705, United States
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Pruis IJ, van Dongen GAMS, Veldhuijzen van Zanten SEM. The Added Value of Diagnostic and Theranostic PET Imaging for the Treatment of CNS Tumors. Int J Mol Sci 2020; 21:E1029. [PMID: 32033160 PMCID: PMC7037158 DOI: 10.3390/ijms21031029] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 01/27/2020] [Accepted: 02/01/2020] [Indexed: 12/11/2022] Open
Abstract
This review highlights the added value of PET imaging in Central Nervous System (CNS) tumors, which is a tool that has rapidly evolved from a merely diagnostic setting to multimodal molecular diagnostics and the guidance of targeted therapy. PET is the method of choice for studying target expression and target binding behind the assumedly intact blood-brain barrier. Today, a variety of diagnostic PET tracers can be used for the primary staging of CNS tumors and to determine the effect of therapy. Additionally, theranostic PET tracers are increasingly used in the context of pharmaceutical and radiopharmaceutical drug development and application. In this approach, a single targeted drug is used for PET diagnosis, upon the coupling of a PET radionuclide, as well as for targeted (nuclide) therapy. Theranostic PET tracers have the potential to serve as a non-invasive whole body navigator in the selection of the most effective drug candidates and their most optimal dose and administration route, together with the potential to serve as a predictive biomarker in the selection of patients who are most likely to benefit from treatment. PET imaging supports the transition from trial and error medicine to predictive, preventive, and personalized medicine, hopefully leading to improved quality of life for patients and more cost-effective care.
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Affiliation(s)
- Ilanah J. Pruis
- Department of Radiology & Nuclear Medicine, Erasmus MC, 3015 GD Rotterdam, The Netherlands;
| | - Guus A. M. S. van Dongen
- Department of Radiology & Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands;
| | - Sophie E. M. Veldhuijzen van Zanten
- Department of Radiology & Nuclear Medicine, Erasmus MC, 3015 GD Rotterdam, The Netherlands;
- Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
- Department of Pediatrics, Amsterdam UMC, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
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50
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Cavaco M, Gaspar D, ARB Castanho M, Neves V. Antibodies for the Treatment of Brain Metastases, a Dream or a Reality? Pharmaceutics 2020; 12:E62. [PMID: 31940974 PMCID: PMC7023012 DOI: 10.3390/pharmaceutics12010062] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 12/13/2019] [Accepted: 12/28/2019] [Indexed: 12/25/2022] Open
Abstract
The incidence of brain metastases (BM) in cancer patients is increasing. After diagnosis, overall survival (OS) is poor, elicited by the lack of an effective treatment. Monoclonal antibody (mAb)-based therapy has achieved remarkable success in treating both hematologic and non-central-nervous system (CNS) tumors due to their inherent targeting specificity. However, the use of mAbs in the treatment of CNS tumors is restricted by the blood-brain barrier (BBB) that hinders the delivery of either small-molecules drugs (sMDs) or therapeutic proteins (TPs). To overcome this limitation, active research is focused on the development of strategies to deliver TPs and increase their concentration in the brain. Yet, their molecular weight and hydrophilic nature turn this task into a challenge. The use of BBB peptide shuttles is an elegant strategy. They explore either receptor-mediated transcytosis (RMT) or adsorptive-mediated transcytosis (AMT) to cross the BBB. The latter is preferable since it avoids enzymatic degradation, receptor saturation, and competition with natural receptor substrates, which reduces adverse events. Therefore, the combination of mAbs properties (e.g., selectivity and long half-life) with BBB peptide shuttles (e.g., BBB translocation and delivery into the brain) turns the therapeutic conjugate in a valid approach to safely overcome the BBB and efficiently eliminate metastatic brain cells.
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Affiliation(s)
| | | | - Miguel ARB Castanho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal; (M.C.); (D.G.)
| | - Vera Neves
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal; (M.C.); (D.G.)
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