posted on 2016-10-25, 00:00authored byAnnelies Cannaert, Jolien Storme, Florian Franz, Volker Auwärter, Christophe P. Stove
Synthetic
cannabinoids (SCs) are the largest group of compounds
currently monitored in Europe by the EU Early Warning System on new
psychoactive substances. Emerging recreational use of these products
has led to multiple cases of adverse health effects and even death.
In contrast to marijuana, where Δ9-tetrahydrocannabinol
(Δ9THC) is metabolized to only one major active metabolite,
it has been reported that several major phase I metabolites of SCs
remain biologically active, exerting cannabinoid (CB) receptor affinity,
potency, and efficacy greater than those of Δ9THC.
It is therefore reasonable that more SCs can also be biotransformed
into molecules with various levels of CB activity. Here, we developed
and applied a new G-protein coupled receptor (GPCR) activation assay
based on NanoLuc binary technology (Promega). More specifically, by
demonstrating CB1 and CB2 receptor activation by JWH-018 and a selection
of its metabolites, we are the first to show the suitability of the
newly developed bioassay for monitoring GPCR-mediated activity. We
also successfully applied this reporter system to evaluate the in
vitro activity of JWH-122, JWH-210, and PB-22, their 5-fluoro analogues
(MAM-2201, EAM-2201, and 5F-PB-22, respectively), and their main phase
I metabolites. By doing so, we demonstrate that several major metabolites
of these SCs retain their activity at cannabinoid receptors. All of
these active metabolites may prolong the parent compound’s
psychotropic and physiological effects and may contribute to its toxicity
profile. We also demonstrate a proof of concept of the applicability
of the newly developed bioassay for screening urine for CB receptor
activity exerted by SCs.