Design, Synthesis, and Evaluation of a New Fluorescent Ligand for the M<sub>2</sub> Muscarinic Acetylcholine Receptor
The M<sub>2</sub> muscarinic acetylcholine receptor (M<sub>2</sub>R) is a G protein-coupled receptor involved in regulating cardiovascular functions and mediation of central muscarinic effects, such as movement, temperature control, and antinociceptive responses. Molecular probes targeting this receptor are therefore important in exploring its pathophysiological role at a molecular level. Herein, we report the design, synthesis, and evaluation of a new fluorescent probe for M<sub>2</sub>R based on an anthranilamide ligand. In radioligand binding experiments, the presented Oregon Green 488-labeled conjugate (<b>33</b>) exhibited high M<sub>2</sub>R affinity (<i>K</i> <sub>i</sub> = 2.4 nM), a moderate preference for the M<sub>2</sub>R over the M<sub>4</sub> receptor, and excellent to pronounced M<sub>2</sub>R selectivity compared to the M<sub>1</sub>, M<sub>3</sub>, and M<sub>5</sub> receptors. The utility of the probe was demonstrated in confocal, two-photon, and stimulated emission depletion nanoscopy (STED) imaging to specifically label the receptors in human embryonic kidney (HEK) 293T cells. These properties suggest that our probe may be utilized in advanced microscopy to study the pharmacology of the M<sub>2</sub>R.
Authors
- Zeinab Nezafat Yazdi
- László Hunyady (ORCID: https://orcid.org/0000-0002-8438-7251)
- Lúcia Wittner (ORCID: https://orcid.org/0000-0001-6800-0953)
- György M. Keserű (ORCID: https://orcid.org/0000-0003-1039-7809)
- Balázs Volk (ORCID: https://orcid.org/0000-0002-2019-1874)
- Renáta Szabó (ORCID: https://orcid.org/0000-0001-7881-2082)
- András Dávid Tóth (ORCID: https://orcid.org/0000-0003-2746-9370)
- Jose Manuel Brea (ORCID: https://orcid.org/0000-0002-5523-1979)
- Marı́a Isabel Loza (ORCID: https://orcid.org/0000-0003-4730-0863)
- Domokos Meszéna
- Dénes Szepesi Kovács
- István Ulbert (ORCID: https://orcid.org/0000-0001-9941-9159)
- Dóra Kiss (ORCID: https://orcid.org/0000-0002-6664-3872)
Institutions
- Semmelweis University (HU)
- Centre for Drug Research and Development (CA)
- Harvard University (US)
- Universidade de Santiago de Compostela (ES)
- Budapest University of Technology and Economics (HU)
- Massachusetts General Hospital (US)
- Egis Pharmaceuticals (Hungary) (HU)
- Center for Neuro-Oncology (US)
- Center for Research in Molecular Medicine and Chronic Diseases (ES)
- Medicina (PL)
- Institute of Cognitive Neuroscience and Psychology (HU)
- Hungarian Academy of Sciences (HU)
- HUN-REN Research Centre for Natural Sciences (HU)
- Egis (France) (FR)
Publication Details
- Journal
- ACS Medicinal Chemistry Letters
- Published
- 2025-03-20
- DOI
- https://doi.org/10.1021/acsmedchemlett.4c00592
- Primary Topic
- Receptor Mechanisms and Signaling
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- European Commission
- Magyar Tudományos Akadémia
- Xunta de Galicia
- Nemzeti Kutatási Fejlesztési és Innovációs Hivatal
- European Regional Development Fund