Novel Inhibitors of the Calcium-Activated K+ Channel KCa3.1 to Treat Non-Alcoholic Fatty Liver Disease and Liver Fibrosis

Liver fibrosis resulting from non-alcoholic fatty liver disease (NAFLD) is a leading cause of liver-related morbidity and mortality. Thecalcium-activatedK Ca3.1 potassium channel is considered a therapeutic target for this disease because of its role in myofibroblasts and T cells, which are key drivers of fibrosis. Here, we describe the development of novel K Ca3.1 inhibitors. Our starting template nifedipine, a dihydropyridine, blocks K Ca3.1 with an IC 50 = 1.8 μM. Nifedipine analogues were screened for blocking of K Ca3.1 using automated planar electrophysiology. Structure-activity-relationship analysis led to the identification of novel analogues with IC 50 in the low nanomolar range. Mutagenesis studies showed that Nifedipine bound to the fenestration region of K Ca3.1, while the new analogues bound in the channel pore. Molecular modeling and simulations were used to characterize the binding of these compounds. In parallel, we tested K Ca3.1 inhibitor TRAM-34 in mice reconstituted with a functional human immune system and fed an obesity-inducing diet. TRAM-34 prevented the progression of NALFD to liver fibrosis, reduced T cell infiltration of the liver and reduced circulating levels of IFN-γ and IL-17. These studies indicate that K Ca3.1 blockers may have use in the treatment of diet-induced liver fibrosis