Opposing Roles of CYP2E1 and ALDH2 in Binge Alcohol-Mediated Cerebellar Damage

To explore the opposing roles between the toxic acetaldehyde-producing enzyme Cytochrome P450-2E1 (CYP2E1) and acetaldehyde-clearing protein mitochondrial Aldehyde Dehydrogenase-2 (ALDH2) in alcohol-mediated cerebellar damage, two separate experiments were conducted. Young Svj/129 wild-type (WT) vs. Cyp2e1-Knockout (KO) mice were administered consecutive doses of 5 g/kg/dose ethanol (EtOH) at 12 h intervals, and C57BL/6J WT vs. Aldh2-KO mice were administered 4 g/kg/dose EtOH at 12 h intervals. Control mice were given dextrose, and cerebella were collected one hour after the last ethanol dose. Cerebellar tissue extracts were used for immunoblot analyses, and frozen tissue sections were evaluated by confocal microscopy with Fluoro-Jade C (FJC) staining for damaged neurons. Rotarod locomotor function of another mouse group was evaluated 48 h after ethanol exposure. Representative immunoblots showed increased levels of oxidative post-translational modifications (PTMs) (e.g., p-Ser/Thr-Pro, Ac-Lys, and acrolein adducts) in EtOH-exposed WT mice, and FJC-staining images revealed more degenerated neurons with decreased locomotor activity in ethanol-exposed WT compared to the corresponding Cyp2e1-KO mice. However, elevated levels of oxidative PTMs were observed in alcohol-exposed Aldh2-KO mice with increased damaged neurons stained with FJC. Our results show that CYP2E1 is a contributing factor, while ALDH2 shows a protective function, demonstrating their opposing roles in binge alcohol-mediated cerebellar degeneration.