Circadian transcription factor NPAS2 and the NAD⁺‐dependent deacetylase SIRT1 interact in the mouse nucleus accumbens and regulate reward

Abstract

Substance use disorders are associated with disruptions to both circadian rhythms and cellular metabolic state. At the molecular level, the circadian molecular clock and cellular metabolic state may be interconnected through interactions with the nicotinamide adenine dinucleotide (NAD+)‐dependent deacetylase, sirtuin 1 (SIRT1). In the nucleus accumbens (NAc), a region important for reward, both SIRT1 and the circadian transcription factor neuronal PAS domain protein 2 (NPAS2) are highly enriched, and both are regulated by the metabolic cofactor NAD+. Substances of abuse, like cocaine, greatly disrupt cellular metabolism and promote oxidative stress; however, their effects on NAD+ in the brain remain unclear. Interestingly, cocaine also induces NAc expression of both NPAS2 and SIRT1, and both have independently been shown to regulate cocaine reward in mice. However, whether NPAS2 and SIRT1 interact in the NAc and/or whether together they regulate reward is unknown. Here, we demonstrate diurnal expression of Npas2, Sirt1 and NAD+ in the NAc, which is altered by cocaine‐induced upregulation. Additionally, co‐immunoprecipitation reveals NPAS2 and SIRT1 interact in the NAc, and cross‐analysis of NPAS2 and SIRT1 chromatin immunoprecipitation sequencing reveals several reward‐relevant and metabolic‐related pathways enriched among shared gene targets. Notably, NAc‐specific Npas2 knock‐down or a functional Npas2 mutation in mice attenuates SIRT1‐mediated increases in cocaine preference. Together, our data reveal an interaction between NPAS2 and SIRT1 in the NAc, which may serve to integrate cocaine's effects on circadian and metabolic factors, leading to regulation of drug reward.

The Ventral Tegmental Area and Nucleus Accumbens as Circadian Oscillators: Implications for Drug Abuse and Substance Use Disorders

“…Using the PER2:LUC mouse model, sustained bioluminescent rhythms have been detected in the NAc ex vivo ( Logan et al, 2015 ; Landgraf et al, 2016a ; Porcu et al, 2020 ). This corroborates gene expression analyses in mice showing significant diurnal variation in molecular clock mRNA levels in the NAc ( Falcon et al, 2013 ; Natsubori et al, 2014 ; Logan et al, 2015 ; Brami-Cherrier et al, 2020 ; Porcu et al, 2020 ; Becker-Krail et al, 2022b ), as well as protein expression analyses in the striatum ( Schnell et al, 2015 ). This is also seen in human post-mortem NAc tissue RNA-sequencing analyses where transcript levels are organized by time-of-death and tested for rhythmicity.…”

“…Notably, while CLOCK seems to play a role in regulating reward through its expression in the VTA, NPAS2 has been shown to regulate reward through its expression in the NAc. The use of Npas2 mutant mice or knockdown of Npas2 in the NAc decreases cocaine conditioned place preference through its expression in D 1 MSNs ( Ozburn et al, 2015 ; Parekh et al, 2019 ; Becker-Krail et al, 2022b ); Npas2 mutant mice actually show significant increases in locomotor response to novelty, exploratory drive, cocaine self-administration and self-administration motivation ( Ozburn et al, 2017 ; DePoy et al, 2020 ). In addition to its enriched expression in the D 1 MSNs of the NAc, this disrupted reward regulation can also be attributed to NPAS2’s transcriptional regulation of reward-related transcripts and downstream regulation of excitatory synaptic transmission and plasticity ( Parekh et al, 2019 ; Becker-Krail et al, 2022b ).…”

“…The use of Npas2 mutant mice or knockdown of Npas2 in the NAc decreases cocaine conditioned place preference through its expression in D 1 MSNs ( Ozburn et al, 2015 ; Parekh et al, 2019 ; Becker-Krail et al, 2022b ); Npas2 mutant mice actually show significant increases in locomotor response to novelty, exploratory drive, cocaine self-administration and self-administration motivation ( Ozburn et al, 2017 ; DePoy et al, 2020 ). In addition to its enriched expression in the D 1 MSNs of the NAc, this disrupted reward regulation can also be attributed to NPAS2’s transcriptional regulation of reward-related transcripts and downstream regulation of excitatory synaptic transmission and plasticity ( Parekh et al, 2019 ; Becker-Krail et al, 2022b ). In addition to NPAS2, loss of function or decreased expression of other molecular clock proteins in the NAc (e.g., CLOCK, PER, CRY, and REV-ERBα) have also been shown to directly alter a whole range of behaviors, including reward, anxiety, cognitive function, stress-susceptibility, mood and depressive-like behaviors ( De Bundel et al, 2013 ; Spencer et al, 2013 ; Landgraf et al, 2016a ; Parekh et al, 2018 ; Zhao and Gammie, 2018 ; Porcu et al, 2020 ).…”

A role for the circadian transcription factor NPAS2 in the progressive loss of non-rapid eye movement sleep and increased arousal during fentanyl withdrawal in male mice

“…Nevertheless, our work suggests NPAS2 may be important for mediating the impact of fentanyl on sleep and wake, and possibly, the homeostatic regulation of sleep during withdrawal from opioids. Although the mechanism by which NPAS2 mediates the effects of fentanyl withdrawal on sleep is unknown, the involvement of NPAS2 in the molecular clock is likely (Franken and Dijk 2009) and may be preferentially involved in modulating arousal and wakefulness through actions in the striatum (Becker-Krail et al 2022;DePoy et al 2021;Garcia et al 2000;Luo et al 2018;Ozburn et al 2015Ozburn et al , 2017Parekh et al 2019;Zhang et al 2021).…”

The circadian neurobiology of reward

“…72 NPAS2 and SIRTUIN-1 are interacting in the NAc and mediate cocaine preference. 85 Chronic cocaine administration disturbs Npas2 rhythms leading to reduced dopamine receptor D3 expression levels in the NAc and induces Npas2 expression in the striatum increasing binding to the Period 1 (Per1) promotor and thereby inducing Per expression in the NAc and caudate putamen. 71,86 Interestingly, cocaine sensitization and reward peak in the early inactive phase in mice when Per1 expression is high.…”