| Summary: | Mutated channelopathy could play important roles in the pathogenesis of aldosterone-producing adenoma (APA). In this study, we identified a somatic mutation, <i>KCNJ5</i> 157-159delITE, and reported its immunohistological, pathophysiological and pharmacological characteristics. We conducted patch-clamp experiments on HEK293T cells and experiments on expression of aldosterone synthase (CYP11B2) and aldosterone secretion in HAC15 cells to evaluate electrophysiological and functional properties of this mutated <i>KCNJ5</i>. Immunohistochemistry was conducted to identify expressions of several steroidogenic enzymes. Macrolide antibiotics and a calcium channel blocker were administrated to evaluate the functional attenuation of mutated <i>KCNJ5</i> channel in transfected HAC15 cells. The interaction between macrolides and KCNJ5 protein was evaluated via molecular docking and molecular dynamics simulation analysis. The immunohistochemistry analysis showed strong CYP11B2 immunoreactivity in the APA harboring <i>KCNJ5</i> 157-159delITE mutation. Whole-cell patch-clamp data revealed that mutated <i>KCNJ5</i> 157-159delITE channel exhibited loss of potassium ion selectivity. The mutant-transfected HAC15 cells increased the expression of CYP11B2 and aldosterone secretion, which was partially suppressed by clarithromycin and nifedipine but not roxithromycin treatment. The docking analysis and molecular dynamics simulation disclosed that roxithromycin had strong interaction with <i>KCNJ5</i> L168R mutant channel but not with this <i>KCNJ5</i> 157-159delITE mutant channel. We showed comprehensive evaluations of the <i>KCNJ5</i> 157-159delITE mutation which revealed that it disrupted potassium channel selectivity and aggravated autonomous aldosterone production. We further demonstrated that macrolide antibiotics, roxithromycin, could not interfere the aberrant electrophysiological properties and gain-of-function aldosterone secretion induced by <i>KCNJ5</i> 157-159delITE mutation.
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