Deficiency of astrocytic TWIK-1 displays increased susceptibility to kainic acid-induced seizures

TWIK-1 is the first identified member of the two-pore domain K+ (K2P) channel family, which plays an essential role in the background K+ conductance of cells. However, the physiological role of TWIK-1 has remained largely unknown since the phenotype of previously reported exon 2-deleted Twik-1 knockout(KO) mice are not clear. Here, we demonstrate, through individual exon-specific short hairpin RNAs (shRNAs) against Twik-1 and CRISPR/Cas9 system to target each exon of the Twik-1 gene, that the exon 2-deleted Twik-1 KO mice express an unexpected functional K+ channel. Furthermore, we generate a new strain of Twik-1 KO mice in which exon 1 was targeted using the CRISPR/Cas9 technique and provide strong evidence, using the new Twik-1 KO mice, to show the potassium buffering role of TWIK-1 in astrocytes. Additionally, deficiency of astrocytic TWIK-1 by cell-type specific gene silencing techniques decreases the potassium buffering function of astrocytes, leading to increased susceptibility to kainic acid-induced seizures. These results clearly showed that TWIK-1 contributes to the astrocytic passive conductance, which is critical in the potassium buffering function of astrocytes in the brain, and the new Twik-1 KO mice can pave the way for functional studies on the physiological role of TWIK-1.