Generation of GABAergic Neurons from Human Induced Pluripotent Stem Cells Using Doxycycline-Inducible ASCL1/DLX2 Expression at AAVS1.

Human induced pluripotent stem cells (hiPSCs) offer an unprecedented opportunity to model human neurological diseases in vitro. Reliable generation of defined neuronal populations, such as gamma-aminobutyric acid (GABAergic) neurons, is essential for these studies. This protocol details a robust method for differentiating hiPSCs into GABAergic neurons using a doxycycline-inducible system. The approach relies on the stable integration of transgenes encoding the transcription factors ASCL1 and DLX2 into the safe-harbor adeno-associated virus integration site 1 (AAVS1.) locus via CRISPR/Cas9-mediated knock-in. This targeted integration avoids the transgene silencing often observed with random lentiviral integration. The protocol covers the maintenance of hiPSCs, the nucleofection process for transgene integration, puromycin selection to enrich successfully engineered cells, and the step-by-step differentiation procedure. Upon induction with doxycycline, the engineered hiPSCs rapidly exit the cell cycle, acquire neuronal morphology, and express GABAergic lineage markers within 21 days. Key steps include neuro-induction and subsequent maturation using specific growth factors, as well as potential approaches to improve cellular adhesion during maturation. This standardized method yields enriched populations of induced neurons expressing GABAergic lineage markers, providing a valuable tool for neuroscience research and cellular modeling.