DREADD Agonist 21 Is an Effective Agonist for Muscarinic-Based DREADDs in Vitro and in Vivo.

Karen Thompson ,Jeffrey F Diberto,Jing Liu,Patrick M Sexton,Xi Ping Huang,Thomas L Kash,Jian Jin,Colin Molloy,Sophie J Bradley,Michael J Krashes,Bryan L Roth,Arthur Christopoulos,Dipanwita Pati,Yan Xiong,Andrew B Tobin,Elham Khajehali,Christoffer Bundgaard,Kristen M Boyt,Melanie M Pina,Reid H.j Olsen ,Jovana Navarrete ,Samuel T Slocum

doi:10.1021/acsptsci.8b00012

Abstract

Chemogenetic tools such as designer receptors exclusively activated by designer drugs (DREADDs) are routinely used to modulate neuronal and non-neuronal signaling and activity in a relatively noninvasive manner. The first generation of DREADDs were templated from the human muscarinic acetylcholine receptor family and are relatively insensitive to the endogenous agonist acetylcholine but instead are activated by clozapine-N-oxide (CNO). Despite the undisputed success of CNO as an activator of muscarinic DREADDs, it has been known for some time that CNO is subject to a low rate of metabolic conversion to clozapine, raising the need for alternative chemical actuators of muscarinic-based DREADDs. Here we show that DREADD agonist 21 (C21) (11-(1-piperazinyl)-5H-dibenzo[b,e][1,4]diazepine) is a potent and selective agonist at both excitatory (hM3Dq) and inhibitory (hM4Di) DREADDs and has excellent bioavailability, pharmacokinetic properties, and brain penetrability. We also show that C21-induced activation of hM3Dq and hM4Di in vivo can modulate bidirectional feeding in defined circuits in mice. These results indicate that C21 represents an alternative to CNO for in vivo studies where metabolic conversion of CNO to clozapine is a concern.

Highlights

Over the past decade, several technologies have been developed to provide chemogenetic modulation of neuronal and non-neuronal signaling
Several technologies have been developed to provide chemogenetic modulation of neuronal and non-neuronal signaling. These include engineered ion channels,[1,2] kinases,[3] and G protein coupled receptors (GPCRs).[4−6] Of these, it is the GPCR-based designer receptors exclusively activated by designer drugs (DREADDs)[6] that are most frequently used among neuroscientists and other biologists
There are several classes of DREADDs including (1) those based on human muscarinic acetylcholine receptors which are coupled to Gαq and activate neuronal signaling and firing,[6,7] (2) those which are coupled to Gαi and inhibit adenylate cyclase and attenuate neuronal activity and neurotransmitter release,[6] and (3) those which preferentially couple to Gαs (GsD),[8] one which preferentially couples to arrestin,[9] and one which

Summary

Introduction

Several technologies have been developed to provide chemogenetic modulation of neuronal and non-neuronal signaling. These include engineered ion channels,[1,2] kinases,[3] and G protein coupled receptors (GPCRs).[4−6] Of these, it is the GPCR-based designer receptors exclusively activated by designer drugs (DREADDs)[6] that are most frequently used among neuroscientists and other biologists. There are several classes of DREADDs including (1) those based on human muscarinic acetylcholine receptors (mAChRs) which are coupled to Gαq (hM1Dq and hM3Dq) and activate neuronal signaling and firing,[6,7] (2) those which are coupled to Gαi (hM4Di) and inhibit adenylate cyclase and attenuate neuronal activity and neurotransmitter release,[6] and (3) those which preferentially couple to Gαs (GsD),[8] one which preferentially couples to arrestin,[9] and one which. The extensive literature using CNO as an effective actuator of muscarinic DREADDs (reviewed in refs 23 and 24)

Methods

Results

Conclusion