The role of dorsal striatal DNMT3b in alcohol seeking behavior after withdrawal.

Relapse after long-term withdrawal in patients with alcohol use disorder(AUD) is closely associated with alcohol-seeking behavior. The dorsal striatum is crucial for alcohol seeking and dependence. DNA methyltransferases (DNMTs)-mediated neural adaptation may represent a key mechanism for alcohol relapse. Here, we investigated the causal role of dorsal striatal DNMTs in relapse. After training rats to self-administer alcohol (14 days, 0.5h/d), to assess relapse behavior, we examined alcohol cue-seeking in rats on withdrawal days 14 and 28. Using Western blotting, we analyzed the expression of DNMT3a and DNMT3b in the dorsal striatum (DS), nucleusaccumbens (NAc), basolateral Amygdala (BLA) and hippocampal CA1 region immediately following the relapse test. To establish causality, we bilaterally injected an adeno-associated virus (AAV) expressing a short hairpin RNA (shRNA) targeting DNMT3b into the DS. We found that DNMT3b expression was selectively upregulated in the DS, but not in the NAc, BLA, or hippocampal CA1 region, on withdrawal day 28 compared to day 14. In contrast, DNMT3a expression remained unaltered across all regions examined.Knockdown of DNMT3b in the DS markedly suppressed alcohol seeking behavior in rats. This study demonstrates that DNMT3b in the DS is a critical mediator of alcohol seeking after long-term withdrawal, thereby identifying a potential molecular target for the treatment of alcohol addiction relapse.