The PDE9A Inhibitor BI-409306 Protects Against Alcohol-Induced Neurotoxicity and Reduces Alcohol Consumption

Alcohol dependence, a severe global health issue, often involves fatal acute intoxication, exacerbated by alcohol-induced oxidative stress and synaptic impairment. This study investigated the neuroprotective potential of BI-409306, a specific PDE9A inhibitor that enhances cGMP signaling, in both in vitro and in vivo alcohol exposure models. In ethanol-injured SH-SY5Y cells, BI mitigated cytotoxicity, stabilized mitochondrial membrane potential, reduced ROS and lipid peroxidation, and upregulated the antioxidant enzyme GPX4. In a chronic mouse model of alcohol dependence, BI administration reduced alcohol consumption and preference, concurrently restoring hippocampal levels of synaptic proteins, dendritic spine density, and GPX4. Furthermore, in an acute alcohol intoxication model, BI treatment improved behavioral outcomes by shortening sedative sleep duration and enhancing motor performance, which was associated with modulated hippocampal GPX4 and the pro-inflammatory cytokine IL-1β. Collectively, these results demonstrate that BI-409306 provides significant protection against alcohol-induced neuronal damage by alleviating oxidative stress and restoring synaptic plasticity, effectively countering both addictive drinking behaviors and acute alcohol toxicity.