Cre‐dependent DREADD (Designer Receptors Exclusively Activated by Designer Drugs) mice

Abstract

DREADDs, designer receptors exclusively activated by designer drugs, are engineered G protein-coupled receptors (GPCR) which can precisely control GPCR signaling pathways (for example, Gq, Gs and Gi). This chemogenetic technology for control of GPCR signaling has been successfully applied in a variety of in vivo studies, including in mice, to remotely control GPCR signaling, for example, in neurons, glia cells, pancreatic beta-cells, or cancer cells. In order to fully explore the in vivo applications of the DREADD technology we generated hM3Dq and hM4Di strains of mice which allow for Cre recombinase-mediated restricted expression of these pathway-selective DREADDs. With the many Cre driver lines now available, these DREADD lines will be applicable to studying a wide array of research and preclinical questions.

Spontaneous and Bite-Evoked Muscle Pain Are Mediated by a Common Nociceptive Pathway With Differential Contribution by TRPV1

“…We took advantage of an inhibitory DREADD in which a modified human muscarinic M4 receptor is coupled to Gi (hM4Di). We employed a newly developed R26R-LSL-hM4Di/mCitrine mouse line that expresses floxed hM4Di and mCitrine from the R26 locus 61 (Fig. 5A).…”

“…Ablation of TRPV1-lineage neurons eliminates heat- and cold responses but mechanical sensitivity is not affected, which shows TRPV1-lineage neurons do not include mechano-sensitive neurons 40 . Second, we used a mouse line conditionally expressing an engineered human muscarinic 4 receptor (hM4Di; Gi-coupled Designer Receptors Exclusively Activated by Designer Drugs (DREADD)) from Rosa26 locus (R26-LSL-hM4Di; https://www.jax.org/strain/026219) 61 . Upon removal of loxP-stop-loxP cassette (LSL) by Cre recombination, the Gi-coupled hM4Di is expressed and the neuronal function is silenced by the administration of clozapine-N-oxide (CNO).…”

A Clock-Driven Neural Network Critical for Arousal

“…Because silencing mWAKE DMH neurons led to a mild phenotype, we chose to inhibit the broad mWAKE + network. To do this, we crossed transgenic mice expressing Cre-dependent DREADD-hM4Di (LSL-Gi) 22 to mWAKE (Cre/+) mice to generate mWAKE (Cre/+) ; LSL-Gi progeny. We first examined the expression pattern of the DREADD-hM4Di in these mice by immunostaining and found that it largely recapitulated the original expression pattern of the mWAKE (Cre/+) mice (Extended Data Fig.…”

Combining designer receptors exclusively activated by designer drugs and neuroimaging in experimental models: A powerful approach towards neurotheranostic applications

“…Urban et al () demonstrated that acute or chronic selective activation of hM3Dq‐expressing dorsal raphe nucleus serotonergic neurons with CNO resulted in distinct metabolic brain responses and behaviours. Moreover, using DREAMM and slice electrophysiology, they observed that hM3Dq exhibited robust and continuous activity after long‐term (3 weeks) stimulation with CNO (Urban, Zhu et al, ). Most recently, Bonaventura et al () demonstrated with DREAMM that JHU37160‐mediated activation of hM3Dq‐ or hM4Di‐expressing dopaminergic D 1 neurons resulted in decreased or increased metabolism in distinct, largely non‐overlapping brain networks, respectively (Bonaventura et al, ).…”

“…In vivo, DREADDs expression in specific cell types is typically achieved by using transgenic mouse models or focal viral vector injections targeting selected brain areas. Various transgenic mouse models have been developed to specifically express DREADDs in selected cell populations by using specific promoters (Farrell et al, ; Guettier et al, ), the transcriptional Tet‐On/Off system (Alexander et al, ) or the Cre‐recombinase system (Zhu et al, ). Transgenic lines lower the inter‐animal variability by offering similar expression levels of DREADDs across all animals, while losing the ability to non‐invasively manipulate the receptors in a region‐specific manner.…”