The A2A adenosine receptor belongs to a family of G‐coupled protein receptors that have been subjected to extensive investigation over the last few decades. Due to their prominent role in the... Show moreThe A2A adenosine receptor belongs to a family of G‐coupled protein receptors that have been subjected to extensive investigation over the last few decades. Due to their prominent role in the biological functions of the heart, lungs, CNS and brain, they have become a target for the treatment of illnesses ranging from cancer immunotherapy to Parkinson's disease. The imaging of such receptors by using positron emission tomography (PET) has also been of interest, potentially providing a valuable tool for analysing and diagnosing various myocardial and neurodegenerative disorders, as well as offering support to drug discovery trials. Reported herein are the design, synthesis and evaluation of two new 5′‐fluorodeoxy‐adenosine (FDA)‐based receptor agonists (FDA‐PP1 and FDA‐PP2), each substituted at the C‐2 position with a terminally functionalised ethynyl unit. The structures enable a synthesis of 18F‐labelled analogues by direct, last‐step radiosynthesis from chlorinated precursors using the fluorinase enzyme (5′‐fluoro‐5′‐deoxyadenosine synthase), which catalyses a transhalogenation reaction. This delivers a new class of A2A adenosine receptor agonist that can be directly radiolabelled for exploration in PET studies. Show less
The Cannabinoid Receptor 2 (CB2R) is a G protein-coupled receptor (GPCR) investigated intensively as therapeutic target, however no drug has reached the market yet. We investigated personal... Show moreThe Cannabinoid Receptor 2 (CB2R) is a G protein-coupled receptor (GPCR) investigated intensively as therapeutic target, however no drug has reached the market yet. We investigated personal differences in CB2R drug responses using a label-free whole-cell assay (xCELLigence) combined with cell lines (Lymphoblastoid Cell Lines) from individuals with varying CB2R genotypes. Responses to agonists, partial agonists and antagonists of various chemical classes were characterized. Endogenous cannabinoids such as 2-AG induced cellular effects vastly different from all synthetic cannabinoids, especially in their time-profile. Secondly, the Q63R polymorphism affected CB2R responses in general. Agonists and especially partial agonists showed higher efficacy in a Q63R minor homozygote versus other genotypes. Non-classical cannabinoid CP55940 showed the most pronounced personal effects with highly reduced potency and efficacy in this genotype. Contrarily, aminoalkylindole compounds showed less individual differences. In conclusion, a label-free whole-cell assay combined with personal cell lines is a promising vehicle to investigate personal differences in drug response originating from genetic variation in GPCRs. Such phenotypic screening allows early identification of compounds prone to personal differences ('precision medicine') or more suited as drugs for the general population. Show less
We report the synthesis and biological evaluation of new 2-amino-4,5-diarylpyrimidines as selective antagonists at the adenosine A(1) receptor. The scaffold they are based upon is a deaza variation... Show moreWe report the synthesis and biological evaluation of new 2-amino-4,5-diarylpyrimidines as selective antagonists at the adenosine A(1) receptor. The scaffold they are based upon is a deaza variation of a previously reported collection of 3-amino-5,6-diaryl-1,2,4-triazines, members of which had a sub-nanomolar affinity but limited selectivity over the A(2A) subtype. Initially, similar structure-affinity relationships at the 5-aryl ring were established, and then emphasis was put on increasing selectivity at the hA(1)AR by introducing substituents on the N-2-position, all the while maintaining a nanomolar affinity. Compound 3z, bearing a trans 4-hydroxycyclohexyl substituent, was identified as a potent (K-i(hA(1)AR) = 7.7 nM) and selective (K-i(hA(2)AAR) = 1389 nM) antagonist at the human adenosine A(1) receptor. Computational docking was effected at the A(1) and A(2A) subtypes, rationalizing the effect of the 4-hydroxycyclohexyl substituent on selectivity, in relation with the nature of the substituent on the 5-position of the pyrimidine. (C) 2016 Elsevier Masson SAS. All rights reserved. Show less
Doornbos, M.L.J.; Cid, J.M.; Haubrich, J.; Nunes, A.G.; Sande, J.W. van de; Vermond, S.C.; ... ; Tresadern, G. 2017
We report the synthesis and biological evaluation of a series of 7-aryl-1,2,4-triazolo[4,3-a]pyridines with mGlu2 positive allosteric modulator (PAM) activity and affinity. Besides traditional in... Show moreWe report the synthesis and biological evaluation of a series of 7-aryl-1,2,4-triazolo[4,3-a]pyridines with mGlu2 positive allosteric modulator (PAM) activity and affinity. Besides traditional in vitro parameters of potency and affinity, kinetic parameters kon, koff and residence time (RT) were determined. The PAMs showed various kinetic profiles; kon values ranged over 2 orders of magnitude, whereas RT values were within a 10-fold range. Association rate constant kon was linearly correlated to affinity. Evaluation of a short, medium, and long RT compound in a label-free assay indicated a correlation between RT and functional effect. The effects of long RT compound 9 on sleep–wake states indicated long RT was translated into sustained inhibition of rapid eye movement (REM) in vivo. These results show that affinity-only driven selection would have resulted in mGlu2 PAMs with high values for kon but not necessarily optimized RT, which is key to predicting optimal efficacy in vivo. Show less
Lenselink, E.B.; Louvel, J.A.; Forti, A.F.; Veldhoven, J.P.D. van; Vries, H. de; Mulder-Krieger, T.; ... ; Beuming, T. 2016
