Investigation of Novel Drug Targets for Stimulant Use Disorder

项目总结 兴奋剂使用障碍(SUD)在美国的发病率呈上升趋势。值得注意的是，没有FDA批准的 目前已有治疗SUD的药物。可卡因和甲基苯丙胺(冰毒)是人类使用的主要兴奋剂。 患有自闭症的个体。因为这些兴奋剂通过单胺转运体(MAT)发挥作用， 调节MAT功能的干预措施可能是有效的SUD治疗方法。我们的团队确认了大脑- 表达的RGS12蛋白是单胺转运蛋白的调制器，RGS蛋白被认为是 成为可下药的目标。因此，我的第一个目标(我的论文研究项目)是评估RGS12抑制作为一种 使用疾病的小鼠模型治疗SUD的潜在策略。我们小组发现，老鼠缺乏 RGS12的功能抵抗各种刺激剂的运动激活作用，包括3，4- 甲基二氧甲基苯丙胺(MDMA)。我早期的论文工作集中在理解为什么RGS12- Null小鼠对MDMA诱导的过度运动具有抵抗力。因为MDMA的主要目标是5-羟色胺转运体 (SERT)，我假设SERT在RGS12基因缺失的小鼠中调节失调。为了检验我的假设，我测量了 利用野生型和RGS12缺失小鼠脑组织的sert表达和功能。我发现， 与野生型小鼠相比，RGS12基因缺失小鼠的SERT表达和功能增强。vt.给出 小鼠RGS12的丢失伴随着SERT表达和功能的增加(我的发现)和 多巴胺转运体(DAT；以前研究生的发现)，因为可卡因针对SERT 而DAT，我假设RGS12基因缺失的小鼠将对可卡因戒断相关行为产生抵抗力。 为了验证我的假设，我评估了之前报道的野生型和非野生型可卡因戒断的体征。 RGS12缺失小鼠。我的结果显示，虽然野生型小鼠在吸食可卡因期间会表现出更多的梳理 停药后，RGS12基因缺失的小鼠不会。在F99培训阶段，我将继续努力验证RGS12作为 通过测量可卡因或冰毒静脉自我给药(IVSA)作为SUD的靶标，这是黄金标准 在实验动物中模拟sud的行为范式。我会确定是否有RGS12基因- 对获得和维持可卡因或冰毒自我管理的相关影响以及对 恢复扑灭的可卡因或冰毒的自我管理。我的第二个目标(我的博士后研究 方向)是表征SUD相关电路中的gprR转录组，因为gpcr是很好的靶标 用于调节电池/电路的活动。在K00训练阶段，我将使用逆行示踪剂来标记单次 投射到与SUD相关的脑区的细胞。然后，我将使用单细胞rna-seq鉴定gpr。 标记细胞的转录组。理想情况下，这些数据将揭示GPCRs，在激活或停用时，将 抑制伏隔核多巴胺的释放。拟议的研究阶段将为我提供充足的 学习新技术的机会。此外，拟议的培训计划将帮助我提高在 演示、写作、指导、教学和领导实验室小组。

PROJECT SUMMARY The incidence of stimulant use disorder (SUD) in the United States is on the rise. Notably, no FDA-approved medications exist to treat SUD. Cocaine and methamphetamine (METH) are the primary stimulants used by individuals with SUD. Because those stimulants exert their effects via monoamine transporters (MATs), interventions that modulate MAT function could be effective SUD treatments. Our group identified the brain- expressed protein RGS12 as being a modulator of monoamine transporters, and RGS proteins are thought to be druggable targets. Thus, my first aim (my dissertation research project) is to evaluate RGS12 inhibition as a potential treatment strategy for SUD using a mouse model of the disease. Our group discovered that mice lacking RGS12 function are resistant to the locomotor-activating effects of various stimulants, including 3,4- methylendedioxymethamphetamine (MDMA). My early dissertation work focused on understanding why RGS12- null mice are resistant to MDMA-induced hyperlocomotion. As MDMA’s primary target is the serotonin transporter (SERT), I hypothesized that SERT was dysregulated in RGS12-null mice. To test my hypothesis, I measured SERT expression and function using brain tissue from wild-type and RGS12-null mice. I discovered that, compared with wild-type mice, RGS12-null mice exhibited increases in SERT expression and function. Given that loss of RGS12 in mice is accompanied by increased expression and function of SERT (my finding) and the dopamine transporter (DAT; a previous graduate student’s finding), and because cocaine targets both SERT and DAT, I hypothesized that RGS12-null mice would be resistant to cocaine withdrawal-associated behaviors. To test my hypothesis, I assessed previously reported somatic signs of cocaine withdrawal in wild-type and RGS12-null mice. My results showed that while wild-type mice display increased grooming during cocaine withdrawal, RGS12-null mice do not. In the F99 training phase, I will continue my efforts to validate RGS12 as a target for SUD by measuring cocaine or METH intravenous self-administration (IVSA), the gold standard behavioral paradigm for modeling SUD in laboratory animals. I will determine if there are Rgs12 genotype- associated effects on the acquisition and maintenance of cocaine or METH self-administration, as well as on reinstatement of extinguished cocaine or METH self-administration. My second aim (my postdoctoral research direction) is to characterize the GPCR transcriptome in SUD-relevant circuitry, as GPCRs are excellent targets for modulating the activities of cells/circuits. In the K00 training phase, I will use retrograde tracers to label single cells that project to SUD-relevant brain regions. I will then identify, using single-cell RNA-seq, the GPCR transcriptome of labeled cells. Ideally, those data will reveal GPCRs that, upon activation or inactivation, will dampen dopamine release in the nucleus accumbens. The proposed research phases will provide me ample opportunities to learn new techniques. Additionally, the proposed training plan will help me improve my skills in presenting, writing, mentoring, teaching, and leading a laboratory group.