Upregulated GIRK2 counteracts ethanol-induced changes in excitability and respiration in human neurons.

Genome-wide association analysis of electroencephalographic endophenotypes for alcohol use disorder has identified non-coding polymorphisms within the KCNJ6 gene. KCNJ6 encodes the GIRK2 protein, a subunit of a G-protein-coupled inwardly-rectifying potassium channel that regulates neuronal excitability. To elucidate how GIRK2 affects neuronal excitability and the response to ethanol exposure, we upregulated KCNJ6 in human glutamatergic neurons derived from induced pluripotent stem cells using two distinct strategies: CRISPRa induction and lentiviral expression. Multi-electrode-arrays, calcium imaging, patch-clamp electrophysiology, and mitochondrial stress tests collectively show that elevated GIRK2 acts in concert with 7-21 days of ethanol exposure to inhibit neuronal activity, to counteract ethanol-induced increases in glutamate sensitivity, and to promote an increase intrinsic excitability. Furthermore, ethanol exposure did not alter basal nor activity-dependent mitochondrial respiration in elevated GIRK2 neurons. These data highlight a role for GIRK2 in mitigating the effects of ethanol on neuronal glutamatergic signaling and mitochondrial activity.