Novel mechanisms of alcohol use disorder revealed by multidimensional animal model

Alcohol use disorder (AUD) is marked by persistent alcohol seeking and impaired behavioral flexibility, particularly during abstinence. We investigated the molecular and synaptic mechanisms underlying deficient extinction of alcohol seeking using an IntelliCage-based mouse model that stratifies animals as AUD-prone (≥2 AUD-like criteria) or AUD-resistant (<2 criteria).

Hippocampal RNA sequencing identified alterations in genes regulating the actin cytoskeleton and synaptic function, including cofilin (Cfl1). These molecular changes were accompanied by impaired synaptic transmission in the molecular layer of the dentate gyrus (ML-DG) in AUD-prone mice. To test causality, we manipulated Cfl1 expression locally in the polymorphic layer of the dentate gyrus (PoDG). Cfl1 overexpression suppressed ML-DG transmission, increased motivation to seek alcohol and sucrose, and impaired extinction of reward seeking. Conversely, reducing Cfl1 levels facilitated extinction, identifying cofilin-dependent synaptic regulation as a key mechanism controlling persistent reward seeking.

Importantly, this mechanism showed translational relevance. Three human CFL1 variants (rs369270402, rs2376005, rs36124259) were associated with increased AUD risk, while peripheral blood CFL1 mRNA levels were associated with alcohol-related hospital readmission.

Together, our findings identify hippocampal cofilin signaling as a molecular link between synaptic dysfunction, impaired behavioral flexibility, and persistent alcohol seeking, and suggest CFL1 as a potential marker of vulnerability and relapse-related phenotypes in AUD.