Alcohol use disorder (AUD) arises from excessive alcohol use, characterized by a pathological drive to drink alcohol and cognitive inflexibility. Using the automated IntelliCage system, researchers used a mouse model of AUD to examine the biological structure of alcohol craving during forced withdrawal. In this model, <2 or ≥2 diagnostic criteria of AUD were applied to classify animals as either AUD-prone or AUD-resistant. Understanding the neural mechanisms underlying all AUD-related behaviours is essential for developing effective preventive and therapeutic strategies.
Patients’ cognitive inflexibility and personal focus on obtaining alcohol were key features of craving during recovery. Similarly, in the mouse model, researchers sought to identify the molecular mechanisms driving alcohol-seeking behaviour. The molecular mechanism remains unclear for the hippocampus’s role in alcohol craving during drinking. But interventions in the dentate gyrus (DG) that disrupt adult neurogenesis have been shown to enhance drug use and drug-seeking behaviors.
Male and female C57BL/6J mice, 10 weeks old, were obtained from the Medical University of Bialystok, Poland. The mouse was kept in a home cage for a 12-hour cycle with unlimited meals and water access. The long-term training was conducted with 58 female mice, including an alcohol introduction phase (days 1 to 12) followed by an alcohol-free access phase (days 13 to 47). Each mouse entering the corner was supported by a cue light that indicated the availability of alcohol.
The examination of daily alcohol intake throughout the course of the training period may be the cause of the surprising absence of association between alcohol consumption and AUD score. Mice with an AUD-like phenotype and AUD-resistant phenotypes were identified using the AUD model. Following the second alcohol elimination test, hippocampal tissue was obtained, total RNA was isolated, and an advanced RNA sequencing technique was performed.
Using the Gene Ontology (GO) platform, differentially expressed genes (DEGs) were categorized based on their cellular component (CC) and molecular function (MF) categories. The ML synapses of acute hippocampus slices were used to measure input-output and paired-pulse ratio (PPR) to assess synaptic functions. The AUD score and PPR slope correlated with alcohol craving during persistence and extinction phases.
The slope of the field excitatory postsynaptic potentials (fEPSP) was positively associated with alcohol intake during relapse and negatively associated with craving during relapse. Compared to alcohol-naive mice, alcohol-trained mice showed enhanced synaptic function. Hippocampal sections obtained after training animals revealed that the polymorphic layer of the hippocampal dentate gyrus (PoDG) cells expressing cofilin (Cfl) exhibited higher F-actin content. The luciferase (shLuc) and short cofilin (shCfl) groups were separated into excellent and poor performers in each AUD test during data analysis. Blood CFL1 mRNA levels did not differ between male and female AUD patients.
These results observed the peripheral cofilin levels that predict hospital readmissions linked to alcohol use, but not a sign of AUD. The study highlighted a correlation between CFL1 mRNA blood levels and hospital admissions related to alcohol use. Three single-nucleotide polymorphisms (SNPs) in the human CFL1 gene were linked to an increased risk of AUD.
References: Salamian A, Pagano R, Skonieczna E, et al. Hippocampal cofilin and CFL1 gene variants are linked to alcohol use disorder phenotypes. Mol Psychiatry. 2025. doi:10.1038/s41380-025-03226-3
