Ein photoschaltbarer Ligand zur Regulierung der Rezeptoraktivierung

Abstract

Über die Art und den zeitlichen Verlauf der Aktivierung von G-Protein-gekoppelten Rezeptoren (GPCRs), insbesondere der muskarinischen Acetylcholinrezeptoren (mACh-oder M-Rezeptoren), ist trotz der enormen therapeutischen Relevanz von M-Rezeptoren und GPCRs wenig bekannt. In der vorliegenden Arbeit haben wir deshalb einen dualsteren Liganden eingesetzt, der sowohl mit der orthosteren Bindungsstelle des Rezeptors,d .h.d erjenigen des Neurotransmitters,a ls auch mit einer allosteren Bindungsstelle interagiert, wobei synthetischeine photoschaltbare (photochrome) Azobenzoleinheit eingebaut wurde.W ir haben die photophysikalischen Eigenschaften des BQCAAI benannten Liganden charakterisiert und seine Einsetzbarkeit als pharmakologisches Werkzeug mit einem Satz von FRET-Techniken am M 1 -Rezeptor untersucht. BQCAAI stellt den ersten photoschaltbaren dualsteren Liganden dar,und seine Aktivitätkann durchLicht reguliert werden. Wirh aben BQCAAI eingesetzt, um den zeitlichen Ablauf verschiedener Prozesse der Rezeptoraktivierung zu untersuchen.

Development of an Indole-Amide-Based Photoswitchable Cannabinoid Receptor Subtype 1 (CB1R) “Cis-On” Agonist

“…After carrying out the photocharacterization of the target compounds, their affinity for CBRs was evaluated in radioligand binding assays. This assay was chosen as the first filter because unlike optical assays in vitro, it can be performed without the need for any external light sources. ,, This makes it easy to exclude possible false negatives due to back-isomerization of the ligands during the assay run or reading process. Radioligand binding studies are useful to check to which extent structural differences between each pair of photoisomers translate into changes in the affinity to the receptor.…”

“…This suggests that these novel compounds have a clear advantage over traditional nonswitchable ligands. It should also be mentioned that the affinity difference at the receptor level seems quite low, but numerous photopharmacological tool compounds have shown much more pronounced effects in assays investigating subsequent steps in the activation cascade, ,,, we even have recently shown an “all-or-nothing” in vivo response between cis - and trans -photoisomers …”

Sign Inversion in Photopharmacology: Incorporation of Cyclic Azobenzenes in Photoswitchable Potassium Channel Blockers and Openers

“…Freely diffusible azobenzene photoswitches that are active in their trans-form have been developed for av ariety of targets.T hese include GPCRs,s uch as the m-opioid receptor, [17] the M1 muscarinic receptor, [54] the sphingosine phosphate receptor S1PR1, [55] and the metabotropic glutamate receptor mGluR5, [18] and ion channels,s uch as GA-BAA, [56,57] a7n AChR, [14] and ionotropic glutamate receptors. [15,37,58] Dark active photopharmaceuticals have also been used to optically control transporters,s uch as GAT1, [21] EAAT1-3, [22,23] and F 1 F 0 -ATPase, [59] as well as enzymes.…”

Novel BQCA‐ and TBPB‐Derived M1 Receptor Hybrid Ligands: Orthosteric Carbachol Differentially Regulates Partial Agonism

“…[19] This approachh as the advantage that it is not reliant on the endogenous neurotransmitter and that biased signaling by activation of as pecific downstream signali sp ossible via as ingle molecule. [21][22][23][24] Furthermore,t he design of the connecting linker represents ac hallenge not only for dualsteric GPCR ligands, but for any kind of bivalent ligand.F or this reason,r andomw alk as well as computational approaches have been used to guide linker design. For this purpose, the connection points have to be chosen carefully in order to avoid alteration of essential functional groups responsible for receptor binding and function.…”

“…[20] In earlier studies, av ariety of dualsteric M 1 ligands have been developed, includingap hotoswitchable BQCA-iperoxoh ybrid. [21][22][23][24] Furthermore,t he design of the connecting linker represents ac hallenge not only for dualsteric GPCR ligands, but for any kind of bivalent ligand.F or this reason,r andomw alk as well as computational approaches have been used to guide linker design. [25] Because the orthosteric and allosteric binding pockets of the M 1 receptor are separated by the so-called "tyrosine lid" formed by three tyrosine residues (Figure1), dualsteric ligands have to bridge these two sites by al inker.W eh ave chosen three different linker lengths for this study.F irst, aC 3 -alkyl chain linker represents the shortestp ossible linker length to bypasst he tyrosine lid.…”