Cardioprotective effects of Cu(II) ATSM in human vascular smooth muscle cells and cardiomyocytes mediated by Nrf2 and DJ-1

Cu-(II) ATSM was developed as a hypoxia sensitive positron emission tomography agent. Recent reports have highlighted the neuroprotective properties of Cu-(II) ATSM, yet there are no reports that it confers cardioprotection. We demonstrate that Cu-(II) ATSM activates the redox-sensitive transcription factor Nrf2 in human coronary artery smooth muscle cells (HCASMC) and cardiac myocytes (HCM), leading to upregulation of antioxidant defense enzymes. Oral delivery of Cu-(II) ATSM in mice induced expression of the Nrf2-regulated enzymes in the heart and aorta. In HCASMC, Cu-(II) ATSM increased expression of the Nrf2 stabilizer DJ-1, and knockdown of Nrf2 or DJ-1 attenuated Cu-(II) ATSM-mediated heme oxygenase-1 and NADPH quinone oxidoreductase-1 induction. Pre-treatment of HCASMC with Cu-(II) ATSM protected against the pro-oxidant effects of angiotensin II (Ang II) by attenuating superoxide generation, apoptosis, proliferation and increases in intracellular calcium. Notably, Cu-(II) ATSM-mediated protection against Ang II-induced HCASMC apoptosis was diminished by Nrf2 knockdown. Acute treatment with Cu-(II) ATSM enhanced the association of DJ-1 with superoxide dismutase-1 (SOD1), paralleled by significant increases in intracellular Cu-(II) levels and SOD1 activity. We describe a novel mechanism by which Cu-(II) ATSM induces Nrf2-regulated antioxidant enzymes and protects against Ang II-mediated HCASMC dysfunction via activation of the Nrf2/DJ-1 axis. Cu-(II) ATSM may provide a therapeutic strategy for cardioprotection via upregulation of antioxidant defenses.