Tori Keefauver^1,2, Nicole L. Horan¹, Lillian Morgan¹, Anisha Saxena¹, Ryan W. Logan^3,4, Gregg E. Homanics², Marianne L. Seney¹, Sean P. Farris², Kyle D. Ketchesin¹

Alcohol misuse is a leading cause of preventable death worldwide. Chronic alcohol is associated with disrupted circadian rhythms, yet molecular mechanisms linking circadian rhythm dysregulation and alcohol consumption are poorly understood. Current FDA-approved treatments for alcohol use disorder (AUD) do not target molecular rhythms or sleep-wake cycles. Mammalian circadian rhythms are regulated by transcription-translation feedback loops that regulate the expression of ‘clock genes’ (e.g. Clock, Per, Arntl encoding for BMAL1). Both human and rodent studies have shown clock gene variants are associated with significant changes in reward-seeking behavior. Evidence suggests astrocytes, non-neuronal brain cells with cell-autonomous rhythms, may regulate both circadian rhythms and reward. In the nucleus accumbens (NAc), a region responsible for modulating alcohol- and reward-related behavior, over 43% of the astrocyte transcriptome is expressed rhythmically. No studies to date have investigated the role of NAc astrocyte rhythmicity in regulating alcohol drinking. We used AAV8-Gfap-Cre to functionally ablate molecular rhythms in NAc astrocytes of BMAL1 floxed mice (n = 6/group/sex). Continuous two-bottle choice (2BC), every other day 2BC, and drinking in the dark assessed alcohol drinking. Sucrose preference, social interaction, and light/dark locomotor boxes assessed reward, social, and locomotor behaviors. BMAL1 functional ablation was not associated with changes in any drinking or behavioral paradigm. Future studies will use operant alcohol self-administration to investigate the role of astrocyte molecular rhythms in motivated alcohol-seeking behavior. Understanding bidirectional relationships between astrocyte molecular rhythms and alcohol consumption will elucidate novel mechanisms of diurnal rhythmicity and inform development of targeted circadian therapeutics for AUD.

¹ Department of Psychiatry, Translational Neuroscience Program, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15261, USA.

² Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15261, USA.

³ Department of Psychiatry, University of Massachusetts Chan Medical School, Worcester, Massachusetts

⁴ Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, Massachusetts

Funding Support: NIAAA R21 (AA031074; KDK, MLS, SPF, GEH, RWL), NIMH K01 (MH128763; KDK), and predoctoral fellowship to TK funded by National Institute of Neurological Disorders and Stroke (NINDS: T32 NS141747).