Role of the STING-IRF3 pathway in ambient GABA homeostasis and cognitive function

Targeting altered expression and/or activity of GABA transporters (GATs) provide therapeutic benefit for age-related impairments, including cognitive dysfunction. However, the mechanisms underlying the transcriptional regulation of GATs are unknown. In the present study, we demonstrated that the stimulator of interferon genes (STING) upregulates GAT1 and GAT3 expression in the brain which resulted in cognitive dysfunction. Genetic and pharmacological intervention of STING suppressed the expression of both GAT1 and GAT3, increased the ambient GABA concentration, and therefore, enhanced tonic GABA A inhibition of principal hippocampal neurons, resulting in spatial learning and working memory deficits in mice in a type I interferon (IFN I)-independent manner. Stimulation of the STING-GAT pathway efficiently restored cognitive dysfunction in STING-deficient mice models. Our study uncovered for the first time that the STING signaling pathway regulates GATs expression in a cell autonomous manner and therefore could be a novel target for GABAergic cognitive deficits. Significance Statement GABA concentration in extracellular space is maintained by GABA release and clearance of GABA back to brain cells for degradation. GABA clearance from the synaptic cleft predominantly depends on level and activity of GABA transporters (GATs) in the brain. Insufficient GABA clearance resulted to an aberrant tonic GABA A inhibition in brain. In this study, we have identified an unusually high GABA content in brain of STING-deficient mice, resulting in cognitive impairment. Our results show that STING regulates GATs expression through STING-TBK1-IRF3 pathway and thus regulates GABAergic tone. This is the first study that indicates that the STING-TBK1-IRF3 signaling pathway maintains GABA homeostasis in brain, which may offer a novel therapeutic target for modulating GABAergic tone in cases of cognitive dysfunction.