Attenuated CaV1.2-BK channel protein interaction in bipolar disorder
Bipolar disorder (BP) is a severe mental illness featured with potential cycling of depressive and manic episodes. The recurrent cycling is known to be associated with poor prognosis. Thus, it is important to decipher the pathophysiological mechanism that may possibly underlie the cycling. In our study, by using BP patient-derived neurons, we discovered the delay of time-to-peak in depolarization-associated intracellular calcium dynamics. This cellular deficit is selectively associated with the number of manic episodes in BP patients, suggesting that this deficit may participate in the mechanism of clinical cycling. We also observed an attenuated protein interaction between the calcium and voltage-activated potassium (BK) channel and the CaV1.2 L-type VGCC in BP patients. Pharmacological and molecular interventions that target CaV1.2-BK protein interaction, directly to BK channel for the amelioration of this attenuated protein interaction rescues the disease-associated intracellular calcium deficit. To test the involvement of BK channel in cycling-associated behaviors, we generated a novel animal model.