I have a really naive quesiton. Does this mean that we can leverage the same system for any GPCRs of which its expression is peripherally restricted to create another potential DREADD chemogenetic actuators?
GPCRs that are exclusively expressed in the periphery would be a promising starting point, as they inherently provide an extra layer of selectivity for peripheral activity. You would still need to modify that GPCR so that it becomes unresponsive to its endogenous ligand and develop a new, peripherally restricted ligand that activates only the mutated receptor and not the wild-type receptor (or other GPCRs).