Metabotropic glutamate receptors (mGlu) regulate multiple functions in the nervous systems and are involved in several neurological disorders. However, selectively targeting individual mGlu subtypes with spatiotemporal precision is still an unmet need. Photopharmacology can address this concern through the utilization of photoswitchable compounds such as optogluram, which is a positive allosteric modulator (PAM) of mGlu that enables the precise control of physiological responses using light but does not have an optimal selectivity profile.
View Article and Find Full Text PDFMetabotropic glutamate receptors (mGluRs) are dimeric G-protein-coupled receptors activated by the main excitatory neurotransmitter, L-glutamate. mGluR activation by agonists binding in the venus flytrap domain is regulated by positive (PAM) or negative (NAM) allosteric modulators binding to the 7-transmembrane domain (7TM). We report the cryo-electron microscopy structures of fully inactive and intermediate-active conformations of mGlu receptor bound to an antagonist and a NAM or an agonist and a PAM, respectively, as well as the crystal structure of the 7TM bound to a photoswitchable NAM.
View Article and Find Full Text PDFThe M muscarinic acetylcholine receptor (mAChR) has emerged as an exciting therapeutic target for the treatment of addiction and behavioral disorders. This has been in part due to promising preclinical studies with the M mAChR selective negative allosteric modulator (NAM), ML375. The binding site of ML375 remains unknown, however, making it difficult to develop improved M mAChR selective modulators.
View Article and Find Full Text PDFACS Pharmacol Transl Sci
October 2020
G protein-coupled receptors (GPCR), including the metabotrobic glutamate 5 receptor (mGlu), are important therapeutic targets and the development of allosteric ligands for targeting GPCRs has become a desirable approach toward modulating receptor activity. Traditional pharmacological approaches toward modulating GPCR activity are still limited since precise spatiotemporal control of a ligand is lost as soon as it is administered. Photopharmacology proposes the use of photoswitchable ligands to overcome this limitation, since their activity can be reversibly controlled by light with high precision.
View Article and Find Full Text PDFMass spectrometry (MS) binding assays are a label-free alternative to radioligand or fluorescence binding assays, so the readout is based on direct mass spectrometric detection of the test ligand. The study presented here describes the development and validation of a highly sensitive, rapid, and robust MS binding assay for the quantification of the binding of the metabotropic glutamate 5 (mGlu5) negative allosteric modulator (NAM), MPEP (2-methyl-6-phenylethynylpyridine) at the mGlu5 allosteric binding site. The LC-ESI-MS/MS (liquid chromatography-electrospray ionization-tandem mass spectrometric) analytical method was established and validated with a deuterated analogue of MPEP as an internal standard.
View Article and Find Full Text PDFAdv Pharmacol
September 2020
G-protein-coupled receptor (GPCR) pharmacology tends to be complex and at times poorly understood. This has led to the development of GPCR-targeting agents that often demonstrate poor pharmacokinetic properties and poor selectivity for their target receptors. One approach that is emerging as a means of addressing these limitations is the use of molecules whose activity can be controlled by light.
View Article and Find Full Text PDFBackground: Alcohol use disorder (AUD) is a major socioeconomic burden on society, and current pharmacotherapeutic treatment options are inadequate. Aberrant alcohol use and seeking alters frontostriatal function.
Methods: We performed genome-wide RNA sequencing and subsequent quantitative polymerase chain reaction and receptor binding validation in the caudate-putamen of human AUD samples to identify potential therapeutic targets.
Proc Natl Acad Sci U S A
December 2019
The human M muscarinic acetylcholine receptor (mAChR) has recently emerged as an exciting therapeutic target for treating a range of disorders, including drug addiction. However, a lack of structural information for this receptor subtype has limited further drug development and validation. Here we report a high-resolution crystal structure of the human M mAChR bound to the clinically used inverse agonist, tiotropium.
View Article and Find Full Text PDFRecent years have seen a large increase in the discovery of allosteric ligands targeting muscarinic acetylcholine receptors (mAChRs). One of the challenges in screening such compounds is to understand their mechanisms of action and define appropriate parameter estimates for affinity, cooperativity and efficacy. Herein we describe the mechanisms of action and structure-activity relationships for a series of "pan-G-coupled" muscarinic acetylcholine (ACh) receptor (mAChR) positive allosteric modulators (PAMs).
View Article and Find Full Text PDFDespite the cost to both individual and society, alcohol use disorders (AUDs) remain a major health risk within society, and both relapse and heavy drinking are still poorly controlled with current medications. Here we demonstrate for the first time that a centrally active and selective negative allosteric modulator for the rat M muscarinic acetylcholine receptor (mAChR), ML375, decreases ethanol self-administration and attenuates cue-induced reinstatement of ethanol seeking in ethanol-preferring (iP) rats. Importantly, ML375 did not affect sucrose self-administration or general locomotor activity indicative of a selective effect on ethanol seeking.
View Article and Find Full Text PDFRecently, the first subtype-selective allosteric modulators of the M5 muscarinic acetylcholine receptor (mAChR) have been described, but their molecular mechanisms of action remain unknown. Using radioligand-binding and functional assays of inositol phosphate (IP) accumulation and Ca(2+) mobilization in a recombinant cell line stably expressing the human M5 mAChR, we investigated the effects of the positive allosteric modulator (PAM), ML380, and negative allosteric modulator, ML375. In functional assays, ML380 caused robust enhancements in the potency of the full agonists, acetylcholine (ACh), carbachol, and oxotremorine-M, while significantly increasing the maximal response to the partial agonist, pilocarpine.
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