Abstract
Reliable and systematic experimental access to diverse cell types is necessary for understanding the neural circuit organization, function, and pathophysiology of the human brain. Methods for targeting human neural populations are scarce and currently center around identifying and engineering transcriptional enhancers and viral capsids. Here we demonstrate the utility of 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 ex vivo human cortical tissues. We designed CellREADR constructs to target two distinct human neuron types, CALB2+ (calretinin) GABAergic interneurons and FOXP2+ (forkhead box protein P2) glutamatergic projection neurons, and validated cell targeting using histological, electrophysiological, and transcriptomic methods. CellREADR-mediated expression of optogenetic effectors and genetically-encoded calcium indicators allowed us to manipulate and monitor these neuronal populations in cortical microcircuits. We further demonstrate that AAV-based CellREADR and enhancer vectors can be jointly used to target different subpopulations in the same preparation. By demonstrating specific, reliable, and programmable experimental access to targeted cell types, our results highlight CellREADR's potential for studying human neural circuits and treating brain disorders with cell type resolution.