Transcriptional signatures of heroin intake and seeking throughout the brain reward circuit

Abstract

Opioid use disorder (OUD) looms as one of the most severe medical crises currently facing society. More effective therapeutics for OUD requires in-depth understanding of molecular changes supporting drug-taking and relapse. Recent efforts have helped advance these aims, but studies have been limited in number and scope. Here, we develop a brain reward circuit-wide atlas of opioid-induced transcriptional regulation by combining RNA sequencing (RNAseq) and heroin self-administration in male mice modeling multiple OUD-relevant conditions: acute heroin exposure, chronic heroin intake, context-induced drug-seeking following prolonged abstinence, and heroin-primed drug-seeking (i.e., relapse). Bioinformatics analysis of this rich dataset identified numerous patterns of molecular changes, transcriptional regulation, brain-region-specific involvement in various aspects of OUD, and both region-specific and pan-circuit biological domains affected by heroin. Integrating RNAseq data with behavioral outcomes using factor analysis to generate an addiction index uncovered novel roles for particular brain regions in promoting addiction-relevant behavior, and implicated multi-regional changes in affected genes and biological processes. Comparisons with RNAseq and genome-wide association studies from humans with OUD reveal convergent molecular regulation that are implicated in drug-taking and relapse, and point to novel gene candidates with high therapeutic potential for OUD. These results outline broad molecular reprogramming that may directly promote the development and maintenance of OUD, and provide a foundational resource to the field for future research into OUD mechanisms and treatment strategies.

Drugs of abuse hijack a mesolimbic pathway that processes homeostatic need

“…S5a) ( 27 ). Consistent with previous transcriptomic profiling by RNA-seq in response to drugs of abuse ( 28, 29 ), this approach reliably captured canonical marker genes temporally associated with the addicted state (Fig. 5b, c and Fig.…”

Shared and divergent transcriptomic regulation in nucleus accumbens D1 and D2 medium spiny neurons by cocaine and morphine

“…Using gene ontology analysis, we found that this hub gene cluster enriched for biological processes related to extracellular matrix (ECM) maintenance and associated collagen biology. This finding was particularly interesting given our recent work profiling transcriptional regulation in a mouse model of OUD, as well as recent findings in postmortem NAc from patients with OUD, both of which implicate an important role for ECM dysregulation in supporting opioid addiction pathology (11,12,30). Nearly all genes in this cluster were associated with module 3 (see sunburst plots in Figure 2), a large gene network containing nearly 5700 genes (Supp Fig 2B).…”

“…Mice were treated with cocaine (20 mg/kg) or morphine (10 mg/kg), at doses known to cause strong rewarding effects in mice (21), or with saline, for 10-15 days, followed by 30 days of long-term withdrawal. The 30 d timepoint was chosen to coincide with a period of abstinence associated with high levels of drug craving that promotes relapse (22), and has been linked to dynamic transcriptional regulation within the NAc for both cocaine and opioids (9,11). At the 30 d time point, animals received a challenge injection of either saline, cocaine, or morphine in the homecage and were euthanized 1h later, at which point the NAc was dissected and flash frozen.…”

“…Central to the neurobiology of both SUDs is the nucleus accumbens (NAc), a critical region in the brain's reward circuitry, which undergoes significant transcriptional alterations in response to chronic drug exposure. Recent studies have begun to elucidate transcriptional disruptions in the NAc associated with CUD and OUD (9)(10)(11)(12) revealing both overlapping and divergent molecular signatures. For instance, both disorders have been linked to alterations in genes associated with biological processes supporting synaptic plasticity, neurotransmission, and intracellular signaling.…”

Circadian rhythm disruptions associated with opioid use disorder in the synaptic proteomes of the human dorsolateral prefrontal cortex and nucleus accumbens

“…Limma-Voom with covariate selection (covariates included TMT plex, sex, age, PMI, and peptide expression) was used to detect differentially expressed (DE) proteins between unaffected subjects and subjects with OUD in homogenate and synaptosome protein fractions for each brain region [23]. Proteins were considered DE if both p<0.05 and log2 fold-change (logFC) were greater than or equal to ±0.26 (20% change in protein expression), as previously used [3,33,34]. Over-representation pathway analyses were completed using clusterProfiler [35] and ReactomePA [36] for DE proteins in homogenates and synaptosomes.…”