ATP Synthase C-Subunit Leak Channel As a Novel Therapeutic Target.

Mitochondrial ATP synthase plays a key role in cell life and death by catalyzing the ATP synthesis and housing a leak channel of mitochondrial permeability transition. Various pharmacological and natural compounds that target mitochondria and ATP synthase were under clinical trials recently including bedaquiline (against mycobacterial tuberculosis) and resveratrol (for treating Alzheimer's disease). Here in this work, we are evaluating the effects of these compounds on the structure and leak channel activity of ATP synthase. Purified ATP synthase from porcine heart mitochondria was reconstituted in a planar lipid bilayer to study the single-channel activity of ATP synthase. Electrophysiological experiments revealed a profound inhibitory effect of bedaquiline on the single channel activity of ATP synthase. Additionally, we observed a concentration-dependent dual role of resveratrol on ATP synthase channel activity. Higher concentrations of resveratrol activated the channel while nanomolar concentrations inhibited the ATP synthase leak channel activity. Similar results were obtained with a less sensitive but more classical calcium retention capacity (CRC) assay for measuring the mitochondrial permeability transition pore (mPTP) opening, establishing the involvement of these compounds in modulating mPTP. Currently, we are investigating the ATP synthase structure bound to these compounds by cryo-electron microscopy (cryo-EM) to explore the channel gating mechanism. These findings will lead to the development of structure-based therapeutic drugs targeting the ATP synthase c-subunit leak channel for treating mPTP-related diseases.