Wednesday, February 5, 2025
2/5/2025
PROJECT SUMMARY Copper (Cu) is an essential micronutrient that is required for growth and development of humans. The requirement of Cu is attributed to its role as a catalytic cofactor for a number of enzymes involved in various physiological processes, including mitochondrial energy production, neurotransmitter biosynthesis, and connective tissue formation. Owing to its diverse roles in cellular and organismal physiology, loss-of-function mutations in genes required for Cu absorption or transport to cuproenzymes often result in fatal infantile disorders. For example, defects in the steps involved in the mitochondrial Cu delivery pathway to cytochrome c oxidase (CcO), a mitochondrial cuproenzyme, are associated with a subset of mitochondrial disorders, while disruption in delivering dietary Cu to different organ systems results in Menkes disease. Currently, therapies for these diseases are experimental and largely ineffective at preventing early mortality. To identify compounds that can deliver Cu to cuproenzymes and thus overcome these defects, we performed a targeted screen for Cu-binding pharmacological agents and identified elesclomol (ES) as a potent Cu-transporting molecule. Our initial studies have shown that low nanomolar concentrations of ES can deliver Cu to CcO in yeast, zebrafish, and mouse models of Cu deficiency. Having made this breakthrough, we are now in position to test our hypothesis that ES, which was originally developed as a cancer drug, can be repurposed to safely deliver Cu to different cuproenzymes and rescue disease phenotypes associated with Cu deficiency disorders. To do this, we will first determine where and how ES releases Cu inside cells and whether this can be achieved without damaging cells. Second, we will utilize our newly constructed zebrafish models with specific defects in systemic or mitochondrial Cu metabolism and a mouse model of Menkes disease to test the efficiency of ES in rescuing mitochondrial, cellular, and organismal phenotypes by delivering Cu to cuproenzymes. Thus, the proposed work will uncover the mechanism of ES-mediated intracellular Cu transport and advance a promising therapeutic molecule for the treatment of debilitating and frequently fatal Cu deficiency disorders.
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