All muscarinic acetylcholine receptors (M1-M5) are expressed in murine brain microvascular endothelium

Abstract

Clinical and experimental studies indicate that muscarinic acetylcholine receptors are potential pharmacological targets for the treatment of neurological diseases. Although these receptors have been described in human, bovine and rat cerebral microvascular tissue, a subtype functional characterization in mouse brain endothelium is lacking. Here, we show that all muscarinic acetylcholine receptors (M1-M5) are expressed in mouse brain microvascular endothelial cells. The mRNA expression of M2, M3, and M5 correlates with their respective protein abundance, but a mismatch exists for M1 and M4 mRNA versus protein levels. Acetylcholine activates calcium transients in brain endothelium via muscarinic, but not nicotinic, receptors. Moreover, although M1 and M3 are the most abundant receptors, only a small fraction of M1 is present in the plasma membrane and functions in ACh-induced Ca2+ signaling. Bioinformatic analyses performed on eukaryotic muscarinic receptors demonstrate a high degree of conservation of the orthosteric binding site and a great variability of the allosteric site. In line with previous studies, this result indicates muscarinic acetylcholine receptors as potential pharmacological targets in future translational studies. We argue that research on drug development should especially focus on the allosteric binding sites of the M1 and M3 receptors.

Allosteric sodium binding cavity in GPR3: a novel player in modulation of Aβ production

“…The crystal structure of the GPR3 receptor is not available yet, thus homology modeling technique was carried out to predict its 3D structure. The sequence was retrieved from the Uniprot database (Uniprot entry: P46089) and the model was generated through the GOMoDo web-server, as in 52 , 53 , 70 , 71 . First, a multiple sequence alignment was generated by the GOMoDo webserver to create a Hidden Markov Model (HMM) for our target.…”

The Role of Endothelial Ca2+ Signaling in Neurovascular Coupling: A View from the Lumen

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