Beside acetylcholinesterase, butyrylcholinestersase could be considered as a putative target of interest for the symptomatic treatment of Alzheimer's disease (AD). As a result of complexity of AD, no molecule has been approved since 2002. Idalopirdine, a 5-HT6 receptors antagonist, did not show its effectiveness in clinical trial despite its evaluation as adjunct to cholinesterase inhibitors. Pleiotropic molecules, known as multitarget directed ligands (MTDLs) are currently developed to tackle the multifactorial origin of AD. In this context, we have developed a pleiotropic carbamate 7, that behaves as a covalent inhibitor of BuChE (IC50 = 0.97 µM). The latter will deliver after hydrolysis compound 6, a potent 5-HT6 receptors antagonist (Ki = 11.4 nM) related to idalopirdine. In silico and in vitro evaluation proving our concept were performed completed with first in vivo results that demonstrate great promise in restoring working memory.

Alzheimer’s disease (AD) is a multifactorial neurodegenerative disease which is still poorly understood. The drugs currently used against AD, mainly acetylcholinesterase inhibitors (AChEI), are considered clinically insufficient and are responsible for deleterious side effects. AChE is, however, currently receiving renewed interest through the discovery of a chaperone role played in the pathogenesis of AD. But AChE could also serve as an activating protein for pleiotropic prodrugs. Indeed, inhibiting central AChE with brain-penetrating designed carbamates which are able to covalently bind to the enzyme and to concomitantly liberate active metabolites in the brain could constitute a clinically more efficient approach which, additionally, is less likely to cause peripheral side effects. We aim in this article to pave the road of this new avenue with an in vitro and in vivo study of pleiotropic prodrugs targeting both the 5-HT4 receptor and AChE, in order to display a neuroprotective activity associated with a sustained restoration of the cholinergic neurotransmission and without the usual peripheral side effects associated with classic AChEI. This plural activity could bring to AD patients effective, relatively safe, symptomatic and disease-modifying therapeutic benefits.