HMOX1 and neurodegenerative disease: For years, attempts have been made to explore the underlying pathogenic factors in the progression of neurodegenerative diseases; one of the key factors responsible for the neurodegeneration is elevated oxidative stress, which is characterized by increased lipid peroxidation, elevation in the levels of reactive oxygen species, and disruption in the levels of master antioxidant regulators, such as Nrf2 and HO-1 [46].