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The chronological evolution of fluorescent GPCR probes for bioimaging. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2023.215040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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2
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Tahk MJ, Laasfeld T, Meriste E, Brea J, Loza MI, Majellaro M, Contino M, Sotelo E, Rinken A. Fluorescence based HTS-compatible ligand binding assays for dopamine D3 receptors in baculovirus preparations and live cells. Front Mol Biosci 2023; 10:1119157. [PMID: 37006609 PMCID: PMC10062709 DOI: 10.3389/fmolb.2023.1119157] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 02/28/2023] [Indexed: 03/18/2023] Open
Abstract
Dopamine receptors are G-protein-coupled receptors that are connected to severe neurological disorders. The development of new ligands targeting these receptors enables gaining a deeper insight into the receptor functioning, including binding mechanisms, kinetics and oligomerization. Novel fluorescent probes allow the development of more efficient, cheaper, reliable and scalable high-throughput screening systems, which speeds up the drug development process. In this study, we used a novel Cy3B labelled commercially available fluorescent ligand CELT-419 for developing dopamine D3 receptor-ligand binding assays with fluorescence polarization and quantitative live cell epifluorescence microscopy. The fluorescence anisotropy assay using 384-well plates achieved Z’ value of 0.71, which is suitable for high-throughput screening of ligand binding. The assay can also be used to determine the kinetics of both the fluorescent ligand as well as some reference unlabeled ligands. Furthermore, CELT-419 was also used with live HEK293-D3R cells in epifluorescence microscopy imaging for deep-learning-based ligand binding quantification. This makes CELT-419 quite a universal fluorescence probe which has the potential to be also used in more advanced microscopy techniques resulting in more comparable studies.
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Affiliation(s)
| | - Tõnis Laasfeld
- Institute of Chemistry, University of Tartu, Tartu, Estonia
- Department of Computer Science, University of Tartu, Tartu, Estonia
| | - Elo Meriste
- Institute of Chemistry, University of Tartu, Tartu, Estonia
| | - Jose Brea
- Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CiMUS), Universidade de Santiago de Compostela, Santiago, Spain
| | - Maria Isabel Loza
- Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CiMUS), Universidade de Santiago de Compostela, Santiago, Spain
| | - Maria Majellaro
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago, Spain
- Celtarys Research S.L., Santiago, Spain
| | - Marialessandra Contino
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari Aldo Moro, Bari, Italy
| | - Eddy Sotelo
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago, Spain
| | - Ago Rinken
- Institute of Chemistry, University of Tartu, Tartu, Estonia
- *Correspondence: Ago Rinken,
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Ali MAS, Hollo K, Laasfeld T, Torp J, Tahk MJ, Rinken A, Palo K, Parts L, Fishman D. ArtSeg-Artifact segmentation and removal in brightfield cell microscopy images without manual pixel-level annotations. Sci Rep 2022; 12:11404. [PMID: 35794119 PMCID: PMC9259686 DOI: 10.1038/s41598-022-14703-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 06/10/2022] [Indexed: 11/10/2022] Open
Abstract
Brightfield cell microscopy is a foundational tool in life sciences. The acquired images are prone to contain visual artifacts that hinder downstream analysis, and automatically removing them is therefore of great practical interest. Deep convolutional neural networks are state-of-the-art for image segmentation, but require pixel-level annotations, which are time-consuming to produce. Here, we propose ScoreCAM-U-Net, a pipeline to segment artifactual regions in brightfield images with limited user input. The model is trained using only image-level labels, so the process is faster by orders of magnitude compared to pixel-level annotation, but without substantially sacrificing the segmentation performance. We confirm that artifacts indeed exist with different shapes and sizes in three different brightfield microscopy image datasets, and distort downstream analyses such as nuclei segmentation, morphometry and fluorescence intensity quantification. We then demonstrate that our automated artifact removal ameliorates this problem. Such rapid cleaning of acquired images using the power of deep learning models is likely to become a standard step for all large scale microscopy experiments.
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Affiliation(s)
- Mohammed A S Ali
- Department of Computer Science, University of Tartu, Narva mnt 18, 51009, Tartu, Estonia
| | - Kaspar Hollo
- Department of Computer Science, University of Tartu, Narva mnt 18, 51009, Tartu, Estonia
| | - Tõnis Laasfeld
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| | - Jane Torp
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| | - Maris-Johanna Tahk
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| | - Ago Rinken
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| | - Kaupo Palo
- PerkinElmer Cellular Technologies Germany GmbH, Hamburg, Germany
| | - Leopold Parts
- Department of Computer Science, University of Tartu, Narva mnt 18, 51009, Tartu, Estonia.
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, Cambridgeshire, UK.
| | - Dmytro Fishman
- Department of Computer Science, University of Tartu, Narva mnt 18, 51009, Tartu, Estonia.
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Tahk MJ, Torp J, Ali MAS, Fishman D, Parts L, Grätz L, Müller C, Keller M, Veiksina S, Laasfeld T, Rinken A. Live-cell microscopy or fluorescence anisotropy with budded baculoviruses-which way to go with measuring ligand binding to M 4 muscarinic receptors? Open Biol 2022; 12:220019. [PMID: 35674179 PMCID: PMC9175271 DOI: 10.1098/rsob.220019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 04/27/2022] [Indexed: 01/04/2023] Open
Abstract
M4 muscarinic acetylcholine receptor is a G protein-coupled receptor (GPCR) that has been associated with alcohol and cocaine abuse, Alzheimer's disease, and schizophrenia which makes it an interesting drug target. For many GPCRs, the high-affinity fluorescence ligands have expanded the options for high-throughput screening of drug candidates and serve as useful tools in fundamental receptor research. Here, we explored two TAMRA-labelled fluorescence ligands, UR-MK342 and UR-CG072, for development of assays for studying ligand-binding properties to M4 receptor. Using budded baculovirus particles as M4 receptor preparation and fluorescence anisotropy method, we measured the affinities and binding kinetics of both fluorescence ligands. Using the fluorescence ligands as reporter probes, the binding affinities of unlabelled ligands could be determined. Based on these results, we took a step towards a more natural system and developed a method using live CHO-K1-hM4R cells and automated fluorescence microscopy suitable for the routine determination of unlabelled ligand affinities. For quantitative image analysis, we developed random forest and deep learning-based pipelines for cell segmentation. The pipelines were integrated into the user-friendly open-source Aparecium software. Both image analysis methods were suitable for measuring fluorescence ligand saturation binding and kinetics as well as for screening binding affinities of unlabelled ligands.
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Affiliation(s)
- Maris-Johanna Tahk
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu, Estonia
| | - Jane Torp
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu, Estonia
| | - Mohammed A. S. Ali
- Department of Computer Science, University of Tartu, Narva Street 20, 51009 Tartu, Estonia
| | - Dmytro Fishman
- Department of Computer Science, University of Tartu, Narva Street 20, 51009 Tartu, Estonia
| | - Leopold Parts
- Department of Computer Science, University of Tartu, Narva Street 20, 51009 Tartu, Estonia
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK
| | - Lukas Grätz
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Christoph Müller
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Max Keller
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Santa Veiksina
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu, Estonia
| | - Tõnis Laasfeld
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu, Estonia
- Department of Computer Science, University of Tartu, Narva Street 20, 51009 Tartu, Estonia
| | - Ago Rinken
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu, Estonia
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Intercellular Communication in the Central Nervous System as Deduced by Chemical Neuroanatomy and Quantitative Analysis of Images: Impact on Neuropharmacology. Int J Mol Sci 2022; 23:ijms23105805. [PMID: 35628615 PMCID: PMC9145073 DOI: 10.3390/ijms23105805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 01/25/2023] Open
Abstract
In the last decades, new evidence on brain structure and function has been acquired by morphological investigations based on synergic interactions between biochemical anatomy approaches, new techniques in microscopy and brain imaging, and quantitative analysis of the obtained images. This effort produced an expanded view on brain architecture, illustrating the central nervous system as a huge network of cells and regions in which intercellular communication processes, involving not only neurons but also other cell populations, virtually determine all aspects of the integrative function performed by the system. The main features of these processes are described. They include the two basic modes of intercellular communication identified (i.e., wiring and volume transmission) and mechanisms modulating the intercellular signaling, such as cotransmission and allosteric receptor–receptor interactions. These features may also open new possibilities for the development of novel pharmacological approaches to address central nervous system diseases. This aspect, with a potential major impact on molecular medicine, will be also briefly discussed.
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BOPPY-based novel fluorescent dopamine D2 and D3 receptor ligands. Bioorg Med Chem Lett 2022; 59:128573. [DOI: 10.1016/j.bmcl.2022.128573] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 12/12/2021] [Accepted: 01/15/2022] [Indexed: 01/20/2023]
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Lavogina D, Laasfeld T, Vardja M, Lust H, Jaal J. Viability fingerprint of glioblastoma cell lines: roles of mitotic, proliferative, and epigenetic targets. Sci Rep 2021; 11:20338. [PMID: 34645858 PMCID: PMC8514540 DOI: 10.1038/s41598-021-99630-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/24/2021] [Indexed: 01/03/2023] Open
Abstract
Despite the use of multimodal treatment combinations, the prognosis of glioblastoma (GB) is still poor. To prevent rapid tumor recurrence, targeted strategies for the treatment of GB are widely sought. Here, we compared the efficacy of focused modulation of a set of signaling pathways in two GB cell lines, U-251 MG and T98-G, using a panel of thirteen compounds targeting cell cycle progression, proliferation, epigenetic modifications, and DNA repair mechanism. In parallel, we tested combinations of these compounds with temozolomide and lomustine, the standard chemotherapy agents used in GB treatment. Two major trends were found: within individual compounds, the lowest IC50 values were exhibited by the Aurora kinase inhibitors, whereas in the case of mixtures, the addition of DNA methyltransferase 1 inhibitor azacytidine to lomustine proved the most beneficial. The efficacy of cell cycle-targeting compounds was further augmented by combination with radiation therapy using two different treatment regimes. The potency of azacytidine and lomustine mixtures was validated using a unique assay pipeline that utilizes automated imaging and machine learning-based data analysis algorithm for assessment of cell number and DNA damage extent. Based on our results, the combination of azacytidine and lomustine should be tested in GB clinical trials.
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Affiliation(s)
- Darja Lavogina
- grid.10939.320000 0001 0943 7661Institute of Clinical Medicine, University of Tartu, L. Puusepa 8, 50406 Tartu, Estonia ,grid.10939.320000 0001 0943 7661Institute of Chemistry, University of Tartu, Tartu, Estonia
| | - Tõnis Laasfeld
- grid.10939.320000 0001 0943 7661Institute of Chemistry, University of Tartu, Tartu, Estonia ,grid.10939.320000 0001 0943 7661Department of Computer Science, University of Tartu, Tartu, Estonia
| | - Markus Vardja
- grid.412269.a0000 0001 0585 7044Department of Radiotherapy and Oncological Therapy, Tartu University Hospital, Tartu, Estonia
| | - Helen Lust
- grid.10939.320000 0001 0943 7661Institute of Clinical Medicine, University of Tartu, L. Puusepa 8, 50406 Tartu, Estonia
| | - Jana Jaal
- grid.10939.320000 0001 0943 7661Institute of Clinical Medicine, University of Tartu, L. Puusepa 8, 50406 Tartu, Estonia ,grid.412269.a0000 0001 0585 7044Department of Radiotherapy and Oncological Therapy, Tartu University Hospital, Tartu, Estonia
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Allikalt A, Purkayastha N, Flad K, Schmidt MF, Tabor A, Gmeiner P, Hübner H, Weikert D. Fluorescent ligands for dopamine D 2/D 3 receptors. Sci Rep 2020; 10:21842. [PMID: 33318558 PMCID: PMC7736868 DOI: 10.1038/s41598-020-78827-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 11/27/2020] [Indexed: 12/11/2022] Open
Abstract
Fluorescent ligands are versatile tools for the study of G protein-coupled receptors. Depending on the fluorophore, they can be used for a range of different applications, including fluorescence microscopy and bioluminescence or fluorescence resonance energy transfer (BRET or FRET) assays. Starting from phenylpiperazines and indanylamines, privileged scaffolds for dopamine D2-like receptors, we developed dansyl-labeled fluorescent ligands that are well accommodated in the binding pockets of D2 and D3 receptors. These receptors are the target proteins for the therapy for several neurologic and psychiatric disorders, including Parkinson’s disease and schizophrenia. The dansyl-labeled ligands exhibit binding affinities up to 0.44 nM and 0.29 nM at D2R and D3R, respectively. When the dansyl label was exchanged for sterically more demanding xanthene or cyanine dyes, fluorescent ligands 10a-c retained excellent binding properties and, as expected from their indanylamine pharmacophore, acted as agonists at D2R. While the Cy3B-labeled ligand 10b was used to visualize D2R and D3R on the surface of living cells by total internal reflection microscopy, ligand 10a comprising a rhodamine label showed excellent properties in a NanoBRET binding assay at D3R.
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Affiliation(s)
- Anni Allikalt
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Nirupam Purkayastha
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Khajidmaa Flad
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Maximilian F Schmidt
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Alina Tabor
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Harald Hübner
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Dorothee Weikert
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany.
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