RNA-programmable cell-type monitoring and manipulation in the human cortex with CellREADR.

Reliable and systematic access to diverse cell types is necessary for understanding the organization, function, and pathophysiology of human neural circuits. Methods for targeting human neural populations are scarce and currently center on identifying transcriptional enhancers and engineering viral capsids. Here, we demonstrate the utility of cell access through RNA sensing by endogenous adenosine deaminase acting on RNA (ADAR) (CellREADR), a programmable RNA sensor-effector technology that couples cellular RNA sensing to effector protein translation, for accessing, monitoring, and manipulating specific neuron types in the human cortex ex vivo. We design CellREADRs to target two subpopulations-calretinin (CALB2) GABAergic interneurons and forkhead box protein P2 (FOXP2) glutamatergic projection neurons-and then validate targeting specificity using histological, electrophysiological, and transcriptomic methods. CellREADR expression of channelrhodopsin and GCamp enables the manipulation and monitoring of these populations in live cortical microcircuits. By demonstrating specific, reliable, and programmable experimental access to human neuronal subpopulations, our results highlight CellREADR's potential for studying neural circuits and treating brain disorders.