Nrf2 deficiency aggravates PM-induced cardiomyopathy by enhancing oxidative stress, fibrosis and inflammation via RIPK3-regulated mitochondrial disorder.

PM is a well-known air pollutant threatening public health, and long-term exposure to PM increases the risk of cardiovascular diseases. Nrf2 plays a pivotal role in the amelioration of PM-induced lung injury. However, if Nrf2 is involved in PM-induced heart injury, and the underlying molecular mechanisms have not been explored. In this study, wild type (Nrf2) and Nrf2 knockout (Nrf2) mice were exposed to PM for 6 months. After PM exposure, Nrf2 mice developed severe physiological changes, lung injury and cardiac dysfunction. In the PM-exposed hearts, Nrf2 deficiency caused significant collagen accumulation through promoting the expression of fibrosis-associated signals. Additionally, Nrf2 mice exhibited greater oxidative stress in cardiac tissues after PM exposure. Furthermore, PM-induced inflammation in heart samples were accelerated in Nrf2 mice through promoting inhibitor of α/nuclear factor κB (IκBα/NF-κB) signaling pathways. We also found that Nrf2 aggravated autophagy initiation and glucose metabolism disorder in hearts of mice with PM challenge. Cardiac receptor-interacting protein kinase 3 (RIPK3) expression triggered by PM was further enhanced in mice with the loss of Nrf2. Collectively, these results suggested that strategies for enhancing Nrf2 could be used to treat PM-induced cardiovascular diseases.