Cocaine regulation of Nr4a1 chromatin bivalency and mRNA in male and female mice

Abstract

Cocaine epigenetically regulates gene expression via changes in histone post-translational modifications (HPTMs). We previously found that the immediate early gene Nr4a1 is epigenetically activated by cocaine in mouse brain reward regions. However, few studies have examined multiple HPTMs at a single gene. Bivalent gene promoters are simultaneously enriched in both activating (H3K4me3 (K4)) and repressive (H3K27me3 (K27)) HPTMs. As such, bivalent genes are lowly expressed but poised for activity-dependent gene regulation. In this study, we identified K4&K27 bivalency at Nr4a1 following investigator-administered cocaine in male and female mice. We applied sequential chromatin immunoprecipitation and qPCR to define Nr4a1 bivalency and expression in striatum (STR), prefrontal cortex (PFC), and hippocampus (HPC). We used Pearson’s correlation to quantify relationships within each brain region across treatment conditions for each sex. In female STR, cocaine increased Nr4a1 mRNA while maintaining Nr4a1 K4&K27 bivalency. In male STR, cocaine enriched repressive H3K27me3 and K4&K27 bivalency at Nr4a1 and maintained Nr4a1 mRNA. Furthermore, cocaine epigenetically regulated a putative NR4A1 target, Cartpt, in male PFC. This study defined the epigenetic regulation of Nr4a1 in reward brain regions in male and female mice following cocaine, and, thus, shed light on the biological relevance of sex to cocaine use disorder.

Cell-type specific profiling of histone post-translational modifications in the adult mouse striatum

“…In this context, loss of H3K4me3/H3K27me3 co-enrichment to H3K4me3 enrichment alone is positively associated with gene induction during neuronal differentiation 20 . However, similar mechanisms may be at play in postmitotic neurons, for stable, long-term changes in gene expression 21 . Here, we characterized cell-type specific hPTM profiles in striatal MSNs.…”

Cocaine-Induced Gene Regulation in D1 and D2 Neuronal Ensembles of the Nucleus Accumbens Revealed by Single-Cell RNA Sequencing

“…Similarly, neuronal activity rapidly induces Fosb , and its ΔFosb isoform in particular accumulates with repeated cocaine exposure and is crucial for long-term neural and behavioral adaptations associated with addiction 18,35 . Cocaine is known to epigenetically activate Nr4a1 , which is integral to neuronal homeostasis and neuroprotection in response to hyper- excitation 57,62 .…”

Sex Chromosome Complement and Estradiol Modify Cocaine Self-Administration Behaviors in Male Mice

“…One target of these histone-modifying genes is a nuclear transcription factor, Nr4a1, and mice with KO of this gene displayed an elevated preference for the cocaine-paired side in a CPP paradigm as compared with wild-type mice [24]. The promoter of nuclear transcription factor, Nr4a1 , accumulated both modifications [24, 41]. Interestingly, this led to an increase in gene expression in females but no change in males.…”

“…Interestingly, this led to an increase in gene expression in females but no change in males. A downstream target of Nr4a1 , prepropeptide cocaine and amphetamine-regulated transcript, which is expressed at high levels during abstinence from cocaine, was enhanced in males but not in females [41]. These data suggest one mechanism by which X-chromosome genes can have sexually dimorphic actions on cocaine-related behaviors.…”