Probing the Histamine H Receptor Binding Site to Explore Ligand Binding Kinetics.

Analysis of structure-kinetic relationships (SKR) can contribute to an improved understanding of receptor-ligand interactions. Here, fragment (4-(2-benzylphenoxy)-1-methylpiperidine) was used in different fragment growing approaches to mimic the putative binding mode of the long residence time (RT) ligands olopatadine, acrivastine, and levocetirizine at the histamine H receptor (HR). SKR analyses reveal that introduction of a carboxylic acid moiety can increase RT at HR up to 11-fold.

Histamine H Receptor Isoforms: Insights from Alternative Splicing to Functional Complexity.

Alternative splicing significantly enhances the diversity of the G protein-coupled receptor (GPCR) family, including the histamine H receptor (HR). This post-transcriptional modification generates multiple HR isoforms with potentially distinct pharmacological and physiological profiles. HR is primarily involved in the presynaptic inhibition of neurotransmitter release in the central nervous system.

A high-affinity, cis-on photoswitchable beta blocker to optically control β-adrenergic receptors in vitro and in vivo.

This study introduces (S)-Opto-prop-2, a second-generation photoswitchable ligand designed for precise modulation of β-adrenoceptor (βAR). Synthesised by incorporating an azobenzene moiety with propranolol, (S)-Opto-prop-2 exhibited a high PSS (photostationary state for cis isomer) percentage (∼90 %) and a favourable half-life (>10 days), facilitating diverse bioassay measurements. In vitro, the cis-isomer displayed substantially higher βAR binding affinity than the trans-isomer (1000-fold), making (S)-Opto-prop-2 one of the best photoswitchable GPCR (G protein-coupled receptor) ligands reported so far.

Multiplex Detection of Fluorescent Chemokine Binding to CXC Chemokine Receptors by NanoBRET.

NanoLuc-mediated bioluminescence resonance energy transfer (NanoBRET) has gained popularity for its ability to homogenously measure ligand binding to G protein-coupled receptors (GPCRs), including the subfamily of chemokine receptors. These receptors, such as ACKR3, CXCR4, CXCR3, play a crucial role in the regulation of the immune system, are associated with inflammatory diseases and cancer, and are seen as promising drug targets. The aim of this study was to optimize NanoBRET-based ligand binding to NLuc-ACKR3 and NLuc-CXCR4 using different fluorescently labeled chemokine CXCL12 analogs and their use in a multiplex NanoBRET binding assay of two chemokine receptors at the same time.

Synthesis and Pharmacological Characterization of New Photocaged Agonists for Histamine H and H Receptors.

The modulation of biological processes with light-sensitive chemical probes promises precise temporal and spatial control. Yet, the design and synthesis of suitable probes is a challenge for medicinal chemists. This article introduces a photocaging strategy designed to modulate the pharmacology of histamine H receptors (HR) and H receptors (HR).