Copper supplementation mitigates Parkinson-like wild-type SOD1 pathology and nigrostriatal degeneration in a novel mouse model

Abstract

Misfolded wild-type superoxide dismutase 1 (disSOD1) protein is implicated in the death of substantia nigra (SN) dopamine neurons in Parkinson disease. Regionally reduced copper availability, and subsequent reduced copper binding to SOD1, is a key factor driving the development of this pathology, suggesting brain copper supplementation may constitute an effective means of preventing its formation. We evaluated whether the blood-brain-barrier-permeable copper delivery drug, CuATSM, attenuated the misfolding and deposition of wild-type disSOD1 and associated neuron death in a novel mouse model that expresses this pathology. These factors were profiled using proteomic and elemental mass spectrometry, together with biochemical and histological workflows. We demonstrated copper supplementation corrects altered post-translational modifications on soluble SOD1 and improves the enzymatic activity of the protein in the brains of these animals. These changes were associated with a significant reduction in disSOD1 pathology and preservation of dopamine neurons in the SN, which were highly correlated with tissue copper levels. Our data position wild-type disSOD1 pathology as a novel drug target for Parkinson disease and suggest that brain copper supplementation may constitute an effective means of slowing SN dopamine neuron death in this disorder.