Identification and Design of a Novel Family of Mitochondrial Protonophores for Bioenergetics Analysis and the Treatment of Ischemia-Reperfusion Injury

Nutrient oxidation is normally coupled to ATP production via a proton cycle across the mitochondrial inner membrane. Small molecule proton transporters (protonophores) enable protons to enter the mitochondrial matrix independently of ATP production and thereby ‘uncouple’ mitochondrial respiration. Mitochondrial protonophore uncouplers improve the efficiency of electron transfer to reduce the production of reactive oxygen species (ROS) and cause mitochondria to respire at a maximal rate. Therefore, mitochondrial uncouplers are used as chemical tools to assess mitochondrial function/dysfunction, and may have clinical applicability in disorders involving mitochondria-derived ROS such as ischemia-reperfusion injury.

A handful of small molecule mitochondrial protonophore uncouplers are known, but they have unwanted activity at other membranes. The primary objective of my thesis project was to identify a mitochondrial uncoupler that lacks activity at the plasma membrane. Herein I report the discovery and validation of BAM15, a novel mitochondrial uncoupler that does not have protonophore activity at the plasma membrane. Structure-activity relationship studies were performed to define the mechanism by which BAM15 uncouples mitochondria. Finally, we demonstrate that BAM15 treatment protects mice from renal ischemia-reperfusion injury. In sum, we conclude that BAM15 is a novel mitochondrial uncoupler that enables a more accurate analysis of cellular and mitochondrial bioenergetics and may have clinical applicability for renal ischemia-reperfusion injury. This work provides a foundation for future chemical engineering and medicinal chemistry to optimize BAM15 for advanced experimental and therapeutic applications.