Circuit-wide gene network analysis reveals sex-specific roles for phosphodiesterase enzymes in cocaine addiction

Cocaine use disorder is a significant public health issue without an effective pharmacological treatment. Successful treatments are hindered in part by an incomplete understanding of the molecular mechanisms in the brain that underly long-lasting maladaptive plasticity and addiction-like behaviors. In this study, we leverage a large RNA-sequencing dataset to generate gene co-expression networks across 6 interconnected regions of the brain’s reward circuitry from mice that underwent saline or cocaine self-administration, followed by a 24-hour or 30-day withdrawal period and a saline or cocaine challenge. We identify phosphodiesterase 1b (Pde1b), a Ca2+/calmodulin-dependent enzyme that catalyzes the hydrolysis of cAMP and cGMP, as one of the top hub genes within a nucleus accumbens (NAc) gene module that was bioinformatically associated with addiction-like behavior. Within Drd1- and Drd2-expressing medium spiny neurons (D1 and D2 MSNs) in the NAc, we found that chronic cocaine selectively upregulates Pde1b expression in D2 MSNs. Using a virus-mediated overexpression approach, we demonstrate that Pde1b in the NAc influences cocaine self-administration behavior, locomotor responses, electrophysiological properties of MSNs, and cocaine-induced transcriptomic adaptations in a cell-type- and sex-dependent manner. Together, we identify novel gene modules across the brain’s reward circuitry associated with addiction-like behavior and explore the role of Pde1b in regulating the molecular, cellular, and behavioral response to cocaine. we overexpressed Pde1b in NAc neurons, injected WT male or female mice with saline or cocaine (20 mg/kg) for 10 days, and performed RNA-seq

可卡因使用障碍是一项亟待解决的重大公共卫生问题，目前尚无有效的药物治疗手段。治疗方案的研发受阻，部分原因在于我们对大脑中介导长期适应性不良可塑性及类成瘾行为的分子机制仍缺乏完整认知。本研究依托大型RNA测序（RNA-sequencing）数据集，针对接受盐水或可卡因自身给药的小鼠，在其分别经历24小时或30天戒断期后予以盐水或可卡因攻击实验，最终构建了大脑奖赏回路6个相互连接脑区的基因共表达网络。我们鉴定出磷酸二酯酶1b（Pde1b）——一种可催化环腺苷酸（cAMP）与环鸟苷酸（cGMP）水解的钙/钙调蛋白依赖性酶——作为伏隔核（NAc）基因模块中的核心枢纽基因之一，生物信息学分析显示该模块与类成瘾行为显著相关。在伏隔核内表达多巴胺D1受体与D2受体的中型多棘神经元（D1、D2 MSNs）中，我们发现慢性可卡因给药可选择性上调D2 MSNs中的Pde1b表达。利用病毒介导的过表达手段，本研究证实伏隔核内的Pde1b可通过细胞类型和性别依赖的方式，调控可卡因自身给药行为、运动应答、中型多棘神经元的电生理特性以及可卡因诱导的转录组适应性变化。综上，本研究鉴定出大脑奖赏回路中与类成瘾行为相关的全新基因模块，并揭示了Pde1b在调控可卡因应答的分子、细胞及行为层面的作用。此外，我们在伏隔核神经元中过表达Pde1b，对野生型（WT）雄性及雌性小鼠予以生理盐水或可卡因（20 mg/kg）连续10天给药，随后开展RNA测序实验。