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Giladi M, Montgomery AP, Kassiou M, Danon JJ. Structure-based drug design for TSPO: Challenges and opportunities. Biochimie 2024:S0300-9084(24)00120-2. [PMID: 38782353 DOI: 10.1016/j.biochi.2024.05.018] [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: 02/19/2024] [Revised: 04/27/2024] [Accepted: 05/21/2024] [Indexed: 05/25/2024]
Abstract
The translocator protein 18 kDa (TSPO) is an evolutionarily conserved mitochondrial transmembrane protein implicated in various neuropathologies and inflammatory conditions, making it a longstanding diagnostic and therapeutic target of interest. Despite the development of various classes of TSPO ligand chemotypes, and the elucidation of bacterial and non-human mammalian experimental structures, many unknowns exist surrounding its differential structural and functional features in health and disease. There are several limitations associated with currently used computational methodologies for modelling the native structure and ligand-binding behaviour of this enigmatic protein. In this perspective, we provide a critical analysis of the developments in the uses of these methods, outlining their uses, inherent limitations, and continuing challenges. We offer suggestions of unexplored opportunities that exist in the use of computational methodologies which offer promise for enhancing our understanding of the TSPO.
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Affiliation(s)
- Mia Giladi
- School of Chemistry, The University of Sydney, 2050, Sydney, NSW, Australia
| | | | - Michael Kassiou
- School of Chemistry, The University of Sydney, 2050, Sydney, NSW, Australia.
| | - Jonathan J Danon
- School of Chemistry, The University of Sydney, 2050, Sydney, NSW, Australia.
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2
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Wongso H, Kurniawan A, Setiadi Y, Kusumaningrum CE, Widyasari EM, Wibawa TH, Mahendra I, Febrian MB, Sriyani ME, Halimah I, Daruwati I, Gunawan R, Achmad A, Nugraha DH, Lesmana R, Nugraha AS. Translocator Protein 18 kDa (TSPO): A Promising Molecular Target for Image-Guided Surgery of Solid Cancers. Adv Pharm Bull 2024; 14:86-104. [PMID: 38585455 PMCID: PMC10997928 DOI: 10.34172/apb.2024.015] [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: 05/01/2023] [Revised: 08/26/2023] [Accepted: 10/08/2023] [Indexed: 04/09/2024] Open
Abstract
The translocator protein 18-kDa (TSPO) is a mitochondrial membrane protein that is previously identified as the peripheral benzodiazepine receptor (PBR). Furthermore, it plays a significant role in a diverse range of biochemical processes, including steroidogenesis, mitochondrial cholesterol transport, cell survival and death, cell proliferation, and carcinogenesis. Several investigations also reported its roles in various types of cancers, including colorectal, brain, breast, prostate, and lung cancers, as well as melanoma. According to a previous study, the expression of TSPO was upregulated in cancer cells, which corresponds to an aggressive phenotype and/or poor prognosis. Consequently, the potential for crafting diagnostic and prognostic tools with a focus on TSPO holds great potential. In this context, several radioligands designed to target this protein have been identified, and some of the candidates have advanced to clinical trials. In recent years, the use of hybrid probes with radioactive and fluorescence molecules for image-guided surgery has exhibited promising results in animal and human studies. This indicates that the approach can serve as a valuable surgical navigator during cancer surgery. The current hybrid probes are built from various molecular platforms, including small molecules, nanoparticles, and antibodies. Although several TSPO-targeted imaging probes have been developed, their development for image-guided surgery of cancers is still limited. Therefore, this review aims to highlight recent findings on the involvement of TSPO in carcinogenesis, as well as provide a new perspective on the potential application of TSPO-targeted hybrid probes for image-guided surgery.
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Affiliation(s)
- Hendris Wongso
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
| | - Ahmad Kurniawan
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Yanuar Setiadi
- Research Center for Environmental and Clean Technology, Research Organization for Life Sciences and Environment, National Research and Innovation Agency, Puspiptek, Banten 15314, Indonesia
| | - Crhisterra E. Kusumaningrum
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Eva M. Widyasari
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Teguh H.A. Wibawa
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Isa Mahendra
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
| | - Muhamad B. Febrian
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Maula E. Sriyani
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Iim Halimah
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Isti Daruwati
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
- Department of Pharmaceutical Analysis and Medicinal Chemistry, Faculty of Pharmacy, Universitas Padjadjaran, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
| | - Rudi Gunawan
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
- Department of Pharmaceutical Analysis and Medicinal Chemistry, Faculty of Pharmacy, Universitas Padjadjaran, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
| | - Arifudin Achmad
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
- Department of Nuclear Medicine and Molecular Theranostics, Faculty of Medicine, Universitas Padjadjaran, Bandung 40161
- Oncology and Stem Cells Working Group, Faculty of Medicine, Universitas Padjadjaran, Bandung 40161
| | | | - Ronny Lesmana
- Department of Biomedical Science, Faculty of Medicine, Universitas Padjadjaran, Jatinangor 45363, Indonesia
- Physiology Molecular, Division of Biological Activity, Central Laboratory, Universitas Padjadjaran, Jatinangor 45363, Indonesia
- Laboratory of Sciences, Graduate School, Universitas Padjadjaran, Bandung, Indonesia
| | - Ari S. Nugraha
- Drug Utilisation and Discovery Research Group, Faculty of Pharmacy, Universitas Jember, Jember 68121, Indonesia
- School of Chemistry and Molecular Biosciences, Molecular Horizons, University of Wollongong, Wollongong, New South Wales, 2522, Australia
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3
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Uzuegbunam BC, Rummel C, Librizzi D, Culmsee C, Hooshyar Yousefi B. Radiotracers for Imaging of Inflammatory Biomarkers TSPO and COX-2 in the Brain and in the Periphery. Int J Mol Sci 2023; 24:17419. [PMID: 38139248 PMCID: PMC10743508 DOI: 10.3390/ijms242417419] [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: 10/24/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023] Open
Abstract
Inflammation involves the activation of innate immune cells and is believed to play an important role in the development and progression of both infectious and non-infectious diseases such as neurodegeneration, autoimmune diseases, pulmonary and cancer. Inflammation in the brain is marked by the upregulation of translocator protein (TSPO) in microglia. High TSPO levels are also found, for example, in macrophages in cases of rheumatoid arthritis and in malignant tumor cells compared to their relatively low physiological expression. The same applies for cyclooxgenase-2 (COX-2), which is constitutively expressed in the kidney, brain, thymus and gastrointestinal tract, but induced in microglia, macrophages and synoviocytes during inflammation. This puts TSPO and COX-2 in the spotlight as important targets for the diagnosis of inflammation. Imaging modalities, such as positron emission tomography and single-photon emission tomography, can be used to localize inflammatory processes and to track their progression over time. They could also enable the monitoring of the efficacy of therapy and predict its outcome. This review focuses on the current development of PET and SPECT tracers, not only for the detection of neuroinflammation, but also for emerging diagnostic measures in infectious and other non-infectious diseases such as rheumatic arthritis, cancer, cardiac inflammation and in lung diseases.
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Affiliation(s)
| | - Christoph Rummel
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, 35392 Gießen, Germany;
- Center for Mind Brain and Behavior, Universities Giessen and Marburg, 35043 Marburg, Germany;
| | - Damiano Librizzi
- Department of Nuclear Medicine, Philipps University of Marburg, 35043 Marburg, Germany;
| | - Carsten Culmsee
- Center for Mind Brain and Behavior, Universities Giessen and Marburg, 35043 Marburg, Germany;
- Institute of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, 35037 Marburg, Germany
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Bartos LM, Kirchleitner SV, Kolabas ZI, Quach S, Beck A, Lorenz J, Blobner J, Mueller SA, Ulukaya S, Hoeher L, Horvath I, Wind-Mark K, Holzgreve A, Ruf VC, Gold L, Kunze LH, Kunte ST, Beumers P, Park HE, Antons M, Zatcepin A, Briel N, Hoermann L, Schaefer R, Messerer D, Bartenstein P, Riemenschneider MJ, Lindner S, Ziegler S, Herms J, Lichtenthaler SF, Ertürk A, Tonn JC, von Baumgarten L, Albert NL, Brendel M. Deciphering sources of PET signals in the tumor microenvironment of glioblastoma at cellular resolution. SCIENCE ADVANCES 2023; 9:eadi8986. [PMID: 37889970 PMCID: PMC10610915 DOI: 10.1126/sciadv.adi8986] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 09/26/2023] [Indexed: 10/29/2023]
Abstract
Various cellular sources hamper interpretation of positron emission tomography (PET) biomarkers in the tumor microenvironment (TME). We developed an approach of immunomagnetic cell sorting after in vivo radiotracer injection (scRadiotracing) with three-dimensional (3D) histology to dissect the cellular allocation of PET signals in the TME. In mice with implanted glioblastoma, translocator protein (TSPO) radiotracer uptake per tumor cell was higher compared to tumor-associated microglia/macrophages (TAMs), validated by protein levels. Translation of in vitro scRadiotracing to patients with glioma immediately after tumor resection confirmed higher single-cell TSPO tracer uptake of tumor cells compared to immune cells. Across species, cellular radiotracer uptake explained the heterogeneity of individual TSPO-PET signals. In consideration of cellular tracer uptake and cell type abundance, tumor cells were the main contributor to TSPO enrichment in glioblastoma; however, proteomics identified potential PET targets highly specific for TAMs. Combining cellular tracer uptake measures with 3D histology facilitates precise allocation of PET signals and serves to validate emerging novel TAM-specific radioligands.
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Affiliation(s)
- Laura M. Bartos
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | | | - Zeynep Ilgin Kolabas
- Institute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Center, Neuherberg, Munich, Germany
- Institute for Stroke and Dementia Research (ISD), University Hospital of Munich, LMU Munich, Munich, Germany
- Graduate School of Systemic Neurosciences (GSN), Munich, Germany
| | - Stefanie Quach
- Department of Neurosurgery, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Alexander Beck
- Center for Neuropathology and Prion Research, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Julia Lorenz
- Department of Neuropathology, Regensburg University Hospital, Regensburg, Germany
| | - Jens Blobner
- Department of Neurosurgery, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Stephan A. Mueller
- Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- DZNE–German Center for Neurodegenerative Diseases, Munich, Germany
| | - Selin Ulukaya
- Institute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Center, Neuherberg, Munich, Germany
- Faculty of Biology, Master of Science Program in Molecular and Cellular Biology, Ludwig-Maximilians-Universität München, Planegg, Germany
| | - Luciano Hoeher
- Institute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Center, Neuherberg, Munich, Germany
| | - Izabela Horvath
- Institute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Center, Neuherberg, Munich, Germany
- School of Computation, Information and Technology (CIT), TUM, Boltzmannstr. 3, 85748 Garching, Germany
| | - Karin Wind-Mark
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Adrien Holzgreve
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Viktoria C. Ruf
- Center for Neuropathology and Prion Research, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Lukas Gold
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Lea H. Kunze
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Sebastian T. Kunte
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Philipp Beumers
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Ha Eun Park
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Melissa Antons
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Artem Zatcepin
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
- DZNE–German Center for Neurodegenerative Diseases, Munich, Germany
| | - Nils Briel
- Center for Neuropathology and Prion Research, Faculty of Medicine, LMU Munich, Munich, Germany
- DZNE–German Center for Neurodegenerative Diseases, Munich, Germany
| | - Leonie Hoermann
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Rebecca Schaefer
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Denise Messerer
- Department of Cardiology, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | | | - Simon Lindner
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Sibylle Ziegler
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Jochen Herms
- Center for Neuropathology and Prion Research, Faculty of Medicine, LMU Munich, Munich, Germany
- DZNE–German Center for Neurodegenerative Diseases, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Stefan F. Lichtenthaler
- Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- DZNE–German Center for Neurodegenerative Diseases, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Ali Ertürk
- Institute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Center, Neuherberg, Munich, Germany
- Institute for Stroke and Dementia Research (ISD), University Hospital of Munich, LMU Munich, Munich, Germany
- Graduate School of Systemic Neurosciences (GSN), Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Joerg C. Tonn
- Department of Neurosurgery, University Hospital of Munich, LMU Munich, Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Louisa von Baumgarten
- Department of Neurosurgery, University Hospital of Munich, LMU Munich, Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Nathalie L. Albert
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Bavarian Cancer Research Center (BZKF), Erlangen, Germany
| | - Matthias Brendel
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
- DZNE–German Center for Neurodegenerative Diseases, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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Cheung G, Lin YC, Papadopoulos V. Translocator protein in the rise and fall of central nervous system neurons. Front Cell Neurosci 2023; 17:1210205. [PMID: 37416505 PMCID: PMC10322222 DOI: 10.3389/fncel.2023.1210205] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 06/07/2023] [Indexed: 07/08/2023] Open
Abstract
Translocator protein (TSPO), a 18 kDa protein found in the outer mitochondrial membrane, has historically been associated with the transport of cholesterol in highly steroidogenic tissues though it is found in all cells throughout the mammalian body. TSPO has also been associated with molecular transport, oxidative stress, apoptosis, and energy metabolism. TSPO levels are typically low in the central nervous system (CNS), but a significant upregulation is observed in activated microglia during neuroinflammation. However, there are also a few specific regions that have been reported to have higher TSPO levels than the rest of the brain under normal conditions. These include the dentate gyrus of the hippocampus, the olfactory bulb, the subventricular zone, the choroid plexus, and the cerebellum. These areas are also all associated with adult neurogenesis, yet there is no explanation of TSPO's function in these cells. Current studies have investigated the role of TSPO in microglia during neuron degeneration, but TSPO's role in the rest of the neuron lifecycle remains to be elucidated. This review aims to discuss the known functions of TSPO and its potential role in the lifecycle of neurons within the CNS.
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Wongso H. Recent progress on the development of fluorescent probes targeting the translocator protein 18 kDa (TSPO). Anal Biochem 2022; 655:114854. [PMID: 35963341 DOI: 10.1016/j.ab.2022.114854] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/06/2022] [Indexed: 11/01/2022]
Abstract
The translocator protein 18 kDa (TSPO) was first identified in 1997, and has now become one of the appealing subcellular targets in medicinal chemistry and its related fields. TSPO involves in a variety of diseases, covering neurodegenerative diseases, psychiatric disorders, cancers, and so on. To date, various high-affinity TSPO ligands labelled with single-photon emission computed tomography (SPECT)/positron emission tomography (PET) radionuclides have been reported, with some third-generation radioligands advanced to clinical trials. On the other hand, only a few number of TSPO ligands have been labelled with fluorophores for disease diagnosis. It is noteworthy that the majority of the TSPO fluorescent probes synthesised to date are based on visible fluorophores, suggesting that their applications are limited to in vitro studies, such as in vitro imaging of cancer cells, post-mortem analysis, and tissue biopsies examinations. In this context, the potential application of TSPO ligands can be broadened for in vivo investigations of human diseases by labelling with near-infrared (NIR)-fluorophores or substituting visible fluorophores with NIR-fluorophores on the currently developed fluorescent probes. In this review article, recent progress on fluorescent probes targeting the TSPO are summarised, with an emphasis on development trend in recent years and application prospects in the future.
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Affiliation(s)
- Hendris Wongso
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency, Puspiptek, Banten, 15314, Indonesia.
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7
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Carboranes in drug discovery, chemical biology and molecular imaging. Nat Rev Chem 2022; 6:486-504. [PMID: 37117309 DOI: 10.1038/s41570-022-00400-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2022] [Indexed: 11/08/2022]
Abstract
There exists a paucity of structural innovation and limited molecular diversity associated with molecular frameworks in drug discovery and biomolecular imaging/chemical probe design. The discovery and exploitation of new molecular entities for medical and biological applications will necessarily involve voyaging into previously unexplored regions of chemical space. Boron clusters, notably the carboranes, offer an alternative to conventional (poly)cyclic organic frameworks that may address some of the limitations associated with the use of novel molecular frameworks in chemical biology or medicine. The high thermal stability, unique 3D structure and aromaticity, kinetic inertness to metabolism and ability to engage in unusual types of intermolecular interactions, such as dihydrogen bonds, with biological receptors make carboranes exquisite frameworks in the design of probes for chemical biology, novel drug candidates and biomolecular imaging agents. This Review highlights the key developments of carborane derivatives made over the last decade as new design tools in medicinal chemistry and chemical biology, showcasing the versatility of this unique family of boron compounds.
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8
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Singh P, Adhikari A, Singh D, Gond C, Tiwari AK. The 18-kDa Translocator Protein PET Tracers as a Diagnostic Marker for Neuroinflammation: Development and Current Standing. ACS OMEGA 2022; 7:14412-14429. [PMID: 35557664 PMCID: PMC9089361 DOI: 10.1021/acsomega.2c00588] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/05/2022] [Indexed: 05/13/2023]
Abstract
Translocator protein (TSPO, 18 kDa) is an evolutionary, well-preserved, and tryptophan-rich 169-amino-acid protein which localizes on the contact sites between the outer and inner mitochondrial membranes of steroid-synthesizing cells. This mitochondrial protein is implicated in an extensive range of cellular activities, including steroid synthesis, cholesterol transport, apoptosis, mitochondrial respiration, and cell proliferation. The upregulation of TSPO is well documented in diverse disease conditions including neuroinflammation, cancer, brain injury, and inflammation in peripheral organs. On the basis of these outcomes, TSPO has been assumed to be a fascinating subcellular target for early stage imaging of the diseased state and for therapeutic purposes. The main outline of this Review is to give an update on dealing with the advances made in TSPO PET tracers for neuroinflammation, synchronously emphasizing the approaches applied for the design and advancement of new tracers with reference to their structure-activity relationship (SAR).
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Affiliation(s)
- Priya Singh
- Department
of Chemistry, Babasaheb Bhimrao Ambedkar
University (A Central University), Lucknow, 226025, Uttar Pradesh, India
| | - Anupriya Adhikari
- Department
of Chemistry, Babasaheb Bhimrao Ambedkar
University (A Central University), Lucknow, 226025, Uttar Pradesh, India
| | - Deepika Singh
- Department
of Chemistry, Babasaheb Bhimrao Ambedkar
University (A Central University), Lucknow, 226025, Uttar Pradesh, India
| | - Chandraprakash Gond
- Department
of Chemistry, Babasaheb Bhimrao Ambedkar
University (A Central University), Lucknow, 226025, Uttar Pradesh, India
| | - Anjani Kumar Tiwari
- Department
of Chemistry, Babasaheb Bhimrao Ambedkar
University (A Central University), Lucknow, 226025, Uttar Pradesh, India
- Address:
Department of Chemistry,
Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh. Tel.: +91-7503381343. Fax: +91-522-2440821. E-mail:
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9
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Giordani A, Menziani MC, Moresco RM, Matarrese M, Paolino M, Saletti M, Giuliani G, Anzini M, Cappelli A. Exploring Translocator Protein (TSPO) Medicinal Chemistry: An Approach for Targeting Radionuclides and Boron Atoms to Mitochondria. J Med Chem 2021; 64:9649-9676. [PMID: 34254805 DOI: 10.1021/acs.jmedchem.1c00379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Translocator protein 18 kDa [TSPO or peripheral-type benzodiazepine receptor (PBR)] was identified in the search of binding sites for benzodiazepine anxiolytic drugs in peripheral regions. In these areas, binding sites for TSPO ligands were recognized in steroid-producing tissues. TSPO plays an important role in many cellular functions, and its coding sequence is highly conserved across species. TSPO is located predominantly on the membrane of mitochondria and is overexpressed in several solid cancers. TSPO basal expression in the CNS is low, but it becomes high in neurodegenerative conditions. Thus, TSPO constitutes not only as an outstanding drug target but also as a valuable marker for the diagnosis of a number of diseases. The aim of the present article is to show the lesson we have learned from our activity in TSPO medicinal chemistry and in approaching the targeted delivery to mitochondria by means of TSPO ligands.
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Affiliation(s)
- Antonio Giordani
- Rottapharm Biotech S.p.A., Via Valosa di Sopra 9, 20900 Monza, Italy
| | - Maria Cristina Menziani
- Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, Via Campi 103, 41121 Modena, Italy
| | - Rosa Maria Moresco
- Department of Medicine and Surgery, University of Milan-Bicocca, Nuclear Medicine Department, San Raffaele Scientific Institute, IBFM-CNR, Via Olgettina 60, 20132 Milano, Italy
| | - Mario Matarrese
- Department of Medicine and Surgery, University of Milan-Bicocca, Nuclear Medicine Department, San Raffaele Scientific Institute, IBFM-CNR, Via Olgettina 60, 20132 Milano, Italy
| | - Marco Paolino
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Mario Saletti
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Germano Giuliani
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Maurizio Anzini
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Andrea Cappelli
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
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Vettermann FJ, Harris S, Schmitt J, Unterrainer M, Lindner S, Rauchmann BS, Palleis C, Weidinger E, Beyer L, Eckenweber F, Schuster S, Biechele G, Ferschmann C, Milenkovic VM, Wetzel CH, Rupprecht R, Janowitz D, Buerger K, Perneczky R, Höglinger GU, Levin J, Haass C, Tonn JC, Niyazi M, Bartenstein P, Albert NL, Brendel M. Impact of TSPO Receptor Polymorphism on [ 18F]GE-180 Binding in Healthy Brain and Pseudo-Reference Regions of Neurooncological and Neurodegenerative Disorders. Life (Basel) 2021; 11:484. [PMID: 34073557 PMCID: PMC8229996 DOI: 10.3390/life11060484] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/19/2021] [Accepted: 05/21/2021] [Indexed: 12/20/2022] Open
Abstract
TSPO-PET tracers are sensitive to a single-nucleotide polymorphism (rs6971-SNP), resulting in low-, medium- and high-affinity binders (LABs, MABs and HABS), but the clinical relevance of [18F]GE-180 is still unclear. We evaluated the impact of rs6971-SNP on in vivo [18F]GE-180 binding in a healthy brain and in pseudo-reference tissue in neuro-oncological and neurodegenerative diseases. Standardized uptake values (SUVs) of [18F]GE-180-PET were assessed using a manually drawn region of interest in the frontoparietal and cerebellar hemispheres. The SUVs were compared between the LABs, MABs and HABs in control, glioma, four-repeat tauopathy (4RT) and Alzheimer's disease (AD) subjects. Second, the SUVs were compared between the patients and controls within their rs6971-subgroups. After excluding patients with prior therapy, 24 LABs (7 control, 5 glioma, 6 4RT and 6 AD) were analyzed. Age- and sex-matched MABs (n = 38) and HABs (n = 50) were selected. The LABs had lower frontoparietal and cerebellar SUVs when compared with the MABs and HABs, but no significant difference was observed between the MABs and HABs. Within each rs6971 group, no SUV difference between the patients and controls was detected in the pseudo-reference tissues. The rs6971-SNP affects [18F]GE-180 quantification, revealing lower binding in the LABs when compared to the MABs and HABs. The frontoparietal and cerebellar ROIs were successfully validated as pseudo-reference regions.
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Affiliation(s)
- Franziska J Vettermann
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Stefanie Harris
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Julia Schmitt
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Marcus Unterrainer
- Department of Radiology, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Simon Lindner
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Boris-Stephan Rauchmann
- Department of Radiology, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
- Department of Psychiatry and Psychotherapy, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Carla Palleis
- Department of Neurology, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Endy Weidinger
- Department of Neurology, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Leonie Beyer
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Florian Eckenweber
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Sebastian Schuster
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Gloria Biechele
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Christian Ferschmann
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Vladimir M Milenkovic
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Christian H Wetzel
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Daniel Janowitz
- Institute for Stroke and Dementia Research, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Katharina Buerger
- Institute for Stroke and Dementia Research, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
| | - Robert Perneczky
- Department of Psychiatry and Psychotherapy, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
- Ageing Epidemiology (AGE) Research Unit, School of Public Health, Imperial College, London SW7 2AZ, UK
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Günter U Höglinger
- German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
- Department of Neurology, Hannover Medical School, 30625 Hannover, Germany
| | - Johannes Levin
- Department of Neurology, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Christian Haass
- German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
- Chair of Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, LMU Munich, 82152 Planegg, Germany
| | - Joerg C Tonn
- Department of Neurosurgery, University Hospital of Munich, 81377 Munich, Germany
| | - Maximilian Niyazi
- Department of Radiation Oncology, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Nathalie L Albert
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
| | - Matthias Brendel
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
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Vaht M. Variation rs6971 in the Translocator Protein Gene ( TSPO) is Associated with Aggressiveness and Impulsivity but Not with Anxiety in a Population-Representative Sample of Young Adults. The Journal of Genetic Psychology 2021; 182:149-162. [PMID: 33769215 DOI: 10.1080/00221325.2021.1896470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Expression of the 18-kDa translocator protein (TSPO), originally identified as a peripheral benzodiazepine receptor, has been found to be altered in several psychiatric disorders. A common single nucleotide polymorphism (rs6971) in the TSPO gene leads to an amino acid substitution, Ala147Thr, which dramatically alters the affinity with which TSPO binds drug ligands. As cholesterol also binds TSPO in the same transmembrane domain, it is suggested that this substitution may impair the ability of TSPO to bind or import cholesterol, and hence may affect steroid synthesis and hypothalamic-pituitary-adrenal function. The analysis was carried out on older birth cohort (n = 655) of the longitudinal Estonian Children Personality, Behavior and Health Study sample. Anxiety, aggressive behavior, impulsiveness, and history of stressful life events were self-reported in various data collection waves. Psychiatric assessment of lifetime prevalence of anxiety disorders was carried out at 25 years of age by experienced clinical psychologists. TSPO rs6971 was genotyped in all participants. TSPO rs6971 was not associated with self-reported levels of anxiety or lifetime prevalence of anxiety disorders. However, participants homozygous for the minor A allele displayed the highest aggressiveness and dysfunctional impulsivity scores. The positive, adaptive aspect of impulsivity was sensitive to stressful life events, as the AA genotype was associated with functional impulsivity only when the participants had experienced a low number of stressful life events during childhood. TSPO rs6971 polymorphism may be related to development of aggressiveness and impulsivity by adulthood, regardless of the participants' gender.
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Affiliation(s)
- Mariliis Vaht
- Institute of Psychology, University of Tartu, Tartu, Estonia.,Institute of Genomics, University of Tartu, Tartu, Estonia
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12
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Cui Y, Liang Y, Ip MSM, Mak JCW. Cigarette smoke induces apoptosis via 18 kDa translocator protein in human bronchial epithelial cells. Life Sci 2021; 265:118862. [PMID: 33301812 DOI: 10.1016/j.lfs.2020.118862] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 11/20/2020] [Accepted: 12/03/2020] [Indexed: 12/13/2022]
Abstract
AIMS The 18 kDa translocator protein (TSPO) - also known as peripheral benzodiazepine receptor, is found to be expressed in lung epithelium and pneumocytes, which is closely associated with the mitochondrial permeability transition pore (mPTP) and apoptosis. Cigarette smoking, a key risk factor for the development of chronic obstructive pulmonary disease (COPD), is known to induce apoptosis. We aimed to investigate TSPO subcellular localization and to examine whether cigarette smoke medium (CSM) induce apoptosis via TSPO in airway epithelial cells. MAIN METHODS TSPO subcellular localization and expression were evaluated using immunofluorescent staining and Western blot analysis respectively. TSPO ligands either PK 11195 (a specific antagonist) or AC-5216 (a specific agonist) were pre-incubated in human bronchial epithelial cells before treating with 2% CSM for measurements of apoptotic cells, mitochondrial membrane potential (ΔΨm), cytoplasmic/mitochondrial reactive oxygen species (ROS) and inflammatory marker interleukin (IL)-8 respectively. KEY FINDINGS TSPO was localized around the nucleus and overlapped with mitochondria in BEAS-2B cells. CSM caused an increase in apoptotic cells along with elevation of TSPO protein expression. Pretreatment of PK 11195 suppressed while AC-5216 potentiated CSM-induced apoptosis, collapse of ΔΨm, elevation of cytoplasmic/mitochondrial ROS levels and IL-8 release. In support, knockdown of TSPO caused a significant suppression of CSM-induced IL-8 release in BEAS-2B cells. SIGNIFICANCE The findings suggest that TSPO may play a crucial role in the regulation of cigarette smoke-induced mitochondrial dysfunction via mPTP. Therefore, the development of specific TSPO antagonists like PK11195 may be beneficial to combat smoking-related diseases, such as COPD.
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Affiliation(s)
- Yuting Cui
- Department of Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Yingmin Liang
- Department of Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Mary S M Ip
- Department of Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Judith C W Mak
- Department of Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China; Department of Pharmacology & Pharmacy, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
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Recent Developments in TSPO PET Imaging as A Biomarker of Neuroinflammation in Neurodegenerative Disorders. Int J Mol Sci 2019; 20:ijms20133161. [PMID: 31261683 PMCID: PMC6650818 DOI: 10.3390/ijms20133161] [Citation(s) in RCA: 144] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 05/20/2019] [Accepted: 05/20/2019] [Indexed: 12/12/2022] Open
Abstract
Neuroinflammation is an inflammatory response in the brain and spinal cord, which can involve the activation of microglia and astrocytes. It is a common feature of many central nervous system disorders, including a range of neurodegenerative disorders. An overlap between activated microglia, pro-inflammatory cytokines and translocator protein (TSPO) ligand binding was shown in early animal studies of neurodegeneration. These findings have been translated in clinical studies, where increases in TSPO positron emission tomography (PET) signal occur in disease-relevant areas across a broad spectrum of neurodegenerative diseases. While this supports the use of TSPO PET as a biomarker to monitor response in clinical trials of novel neurodegenerative therapeutics, the clinical utility of current TSPO PET radioligands has been hampered by the lack of high affinity binding to a prevalent form of polymorphic TSPO (A147T) compared to wild type TSPO. This review details recent developments in exploration of ligand-sensitivity to A147T TSPO that have yielded ligands with improved clinical utility. In addition to developing a non-discriminating TSPO ligand, the final frontier of TSPO biomarker research requires developing an understanding of the cellular and functional interpretation of the TSPO PET signal. Recent insights resulting from single cell analysis of microglial phenotypes are reviewed.
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