Thousandfold Cell-Specific Pharmacology of Neurotransmission

Abstract

SUMMARYCell-specific pharmaceutical technologies promise mechanistic insight into clinical drugs―those that treat, and often define, human disease. In particular,DART(drug acutely restricted by tethering) achieves genetically programmable control of drug concentration over cellular dimensions. The method is compatible with clinical pharmaceuticals and amenable to studies in behaving animals. Here, we describeDART.2, comprising three advances. First, we improve the efficiency of chemical capture, enabling cell-specific accumulation of drug to ∼3,000-times the ambient concentration in 15 min. Second, we develop tracer reagents, providing a behavior-independent measure of cellular target engagement in each animal. Third, we extend the method to positive allosteric modulators and outline design principles for this clinically significant class. We showcase the platform with four pharmaceuticals―two that weaken excitatory (AMPAR) or inhibitory (GABAAR) chemical neurotransmission, and two that strengthen these forms of synaptic communication. Across four labs, we tested reagents in the mouse cerebellum, basal ganglia, visual cortex, and retina. Collectively, we demonstrate robust, bidirectional editing of chemical neurotransmission. We provide for distribution of validated reagents, community design principles, and synthetic building blocks for application to diverse pharmaceuticals.

Protein-Based Tools for Studying Neuromodulation

“…Membrane-tethered synthetic ligands via self-labeling proteins such as HaloTag and SNAP-tag can be applied to modulate endogenous GPCR’s activity . DART (drugs acutely restricted by tethering) , is composed of a synthetic drug with reduced potency attached to a HaloTag ligand via a PEG linker. The drug–HaloTag ligand conjugate is then anchored to the cell surface, where HaloTag is expressed.…”

Natural phasic inhibition of dopamine neurons signals cognitive rigidity

“…Mice lacking the ꞵ 3 subunit of GABA A receptors, specifically in DA neurons, showed normal extinction learning; however chronic compensatory changes were seen even in non-dopaminergic cells 37 . To circumvent these issues, we focused on an innovative drug-targeting technology, DART, which offers the ability to perform cell-specific, receptor-specific manipulations that take hold within minutes 38,39 .…”

Fundamental Neurochemistry Review: GABAA receptor neurotransmission and epilepsy: Principles, disease mechanisms and pharmacotherapy

“…Here, chimeric ligand‐gated ion channels sensitive to an effector molecule with reduced off‐target effects (PSAM/PSEM), or mutated GPCRs that bind inert compounds to mediate an inhibitory or excitatory influence (DREADDS) can be expressed under the control of a cell population‐specific promotor. An alternative novel approach enables a ligand to be concentrated at the membrane surface of a cell type of interest via the expression of a transmembrane anchor and self‐labelling protein tag, known as drugs acutely restricted by tethering (DART) (Shields et al, 2022). Optochemogenetic techniques may, in future, further enhance both regional and temporal pharmacologic precision.…”