Epub – Biological Psychiatry
Astrocyte molecular clock function in the nucleus accumbens is important for reward-related behavior

Becker-Krail DD, Ketchesin KD, Burns JN, Zong W, Hildebrand MA, DePoy LM, Vadnie CA, Tseng GC, Logan RW, Huang YH, McClung CA

Background: Substance use disorders (SUDs) are associated with disruptions in circadian rhythms. Both human and animal work has shown the integral role for circadian clocks in the modulation of reward behaviors. Interestingly, astrocytes have emerged as key regulators of circadian rhythmicity. However, no studies to date have identified the role of circadian astrocyte function in the nucleus accumbens (NAc), a hub for reward regulation, or determined the importance of these rhythms for reward-related behavior.
Methods: Using astrocyte-specific RNA-sequencing across time-of-day, we first characterized diurnal variation of the NAc astrocyte transcriptome. We then investigated the functional significance of this circadian regulation through viral-mediated disruption of molecular clock function in NAc astrocytes, followed by assessment of reward-related behaviors, metabolic-related molecular assays, and whole-cell electrophysiology in the NAc.
Results: Strikingly, ∼43% of the astrocyte transcriptome has a diurnal rhythm and key metabolic pathways were enriched among the top rhythmic genes. Moreover, mice with a viral-mediated loss of molecular clock function in NAc astrocytes show a significant increase in locomotor response to novelty, exploratory drive, operant food self-administration and motivation. At the molecular level, these animals also show disrupted metabolic gene expression, along with significant downregulation of both lactate and glutathione levels in the NAc. Importantly, loss of NAc astrocyte clock function also significantly altered glutamatergic signaling onto neighboring medium spiny neurons, alongside upregulated glutamate-related gene expression.
Conclusions: Taken together, these findings demonstrate a novel role for astrocyte circadian molecular clock function in the regulation of the NAc and reward-related behaviors.

Becker-Krail DD, Ketchesin KD, Burns JN, Zong W, Hildebrand MA, DePoy LM, Vadnie CA, Tseng GC, Logan RW, Huang YH, McClung CA. Astrocyte molecular clock function in the nucleus accumbens is important for reward-related behavior. Biol Psychiatry. 2022 Feb 18. doi: 10.1016/j.biopsych.2022.02.007. [Epub ahead of print].

https://www.biologicalpsychiatryjournal.com/article/S0006-3223(22)00094-4/fulltext#relatedArticles