KCNJ2 and atrial fibrillation: MicroRNA-26 (miR-26) was downregulated in KCNJ2-upregulated AF animals and patients, and the knockdown, inhibition, or binding-site mutation of miR-26 enhanced the expression of KCNJ2, establishing that KCNJ2 is a miR-26 target (Luo et al. 2013).