Pathogenesis of hypertension in a mouse model for human CLCN2 related hyperaldosteronism.

Human primary aldosteronism (PA) can be caused by mutations in several ion channel genes but mouse models replicating this condition are lacking. We now show that almost all known PA-associated CLCN2 mutations markedly increase ClC-2 chloride currents and generate knock-in mice expressing a constitutively open ClC-2 Cl channel as mouse model for PA. The Clcn2 allele strongly increases the chloride conductance of zona glomerulosa cells, provoking a strong depolarization and increasing cytoplasmic Ca concentration. Clcn2 mice display typical features of human PA, including high serum aldosterone in the presence of low renin activity, marked hypertension and hypokalemia. These symptoms are more pronounced in homozygous Clcn2 than in heterozygous Clcn2 mice. This difference is attributed to the unexpected finding that only ~50 % of Clcn2 zona glomerulosa cells are depolarized. By reproducing essential features of human PA, Clcn2 mice are a valuable model to study the pathological mechanisms underlying this disease.