Functional study of the role of SAPAP3 postsynaptic density protein on dorsolateral striatal cholinergic interneurons

项目总结/摘要 强迫症（OCD）是一种神经精神疾病，被列为十大和十五大最严重的致残性疾病。 根据2017年《柳叶刀》的数据，女性和男性的患病率分别为 美国2.3%。强迫症在人类中的特征是强迫性思维模式 和强迫性运动行为突触缺陷与精神和神经发育有关 疾病，包括强迫症，但疾病相关的突触蛋白对细胞，电路， 行为输出不完全理解。SAPAP 3是一种突触蛋白，其突变与 强迫症的诊断。组成性SAPAP 3缺失小鼠产生强迫性运动梳理 行为，这是挽救慢性管理的选择性5-羟色胺再摄取抑制剂（SSRIs）和 纹状体定位的SAPAP 3再表达。因此，强迫症的SAPAP 3缺失模型具有症状性 以及治疗有效性，并可用于研究细胞和回路水平的纹状体功能障碍 这种强迫性运动表型的基础。初步证据强调纹状体胆碱能中间神经元 （ChIs）作为该模型中广泛纹状体失调的可能贡献者。这些细胞表现出 在SAPAP 3缺乏的纹状体中诱发乙酰胆碱（ACh）的释放，这可以调节纹状体回路 通过广泛表达的乙酰胆碱受体的无数亚型。这个建议结合了电生理学， 光遗传学和双光子扫描激光显微镜（2 PLSM）来测试总体假设， ChIs的功能失调与适应不良的纹状体ACh释放和强迫性运动行为有关， SAPAP 3缺失模型。 在（目的1）中，将使用离体脑切片中的膜片钳电生理学来比较内在ChI功能， 脑切片免疫组织化学将用于探测突触ACh释放机制。这将揭开 SAPAP 3缺失对ChIs释放ACh相关内在功能特性的影响(Aim（2）意志 利用病毒光遗传学和ACh传感器构建体、电生理学和2 PLSM来测试输入特异性 突触诱发纹状体ACh释放的变化。最后，（目标3）将选择性地拯救SAPAP 3 表达，以测试该模型的纹状体ACh释放中断和OCD样表型是否本质上是 由这些细胞中的SAPAP 3缺失驱动。这将告知ChI靶向治疗是否足以 改变这种强迫症样的电路和行为表型。

PROJECT SUMMARY/ABSTRACT Obsessive Compulsive Disorder (OCD) is a neuropsychiatric disease listed in top 10 and top 15 most disabling illnesses in women and men, respectively, according to the Lancet in 2017 and has a predicted prevalence of 2.3% in the United States. OCD is characterized symptomatically in humans by obsessive thought patterns and compulsive motor behaviors. Synaptic deficits have been linked to psychiatric and neurodevelopmental diseases, including OCD, but the influence of disease-linked synaptic proteins on cellular, circuit, and behavioral outputs are incompletely understood. SAPAP3 is a synaptic protein, whose mutation is correlated with OCD diagnosis in humans. Constitutive SAPAP3 deletion in mice produces compulsive motor grooming behaviors, which are rescued by chronic administration of selective serotonin reuptake inhibitors (SSRIs) and striatum-localized SAPAP3 re-expression. The SAPAP3-deletion model of OCD, therefore, has symptomatic as well as treatment validity and can be used to investigate cellular- and circuit-level striatal dysfunctions underlying this compulsive motor phenotype. Preliminary evidence highlights striatal cholinergic interneurons (ChIs) as a likely contributor of widespread striatal dysregulation in this model. These cells display increased evoked release of Acetylcholine (ACh) in the SAPAP3-lacking striatum, which can modulate striatal circuits through myriad subtypes of widely expressed ACh receptors. This proposal combines electrophysiology, optogenetics, and 2-photon scanning laser microscopy (2PLSM) to test the overarching hypothesis, that functional dysregulation of ChIs is tied to maladaptive striatal ACh release and compulsive motor behavior in the SAPAP3-lacking model. In (Aim 1), patch-clamp electrophysiology in ex vivo brain slices will be used to compare intrinsic ChI function, and brain slice immunohistochemistry will be used to probe synaptic ACh release machinery. This will uncover SAPAP3 deletion’s impacts on intrinsic functional properties related to ACh release by ChIs. (Aim 2) will leverage viral optogenetic and ACh sensor constructs, electrophysiology, and 2PLSM to test for input-specific changes to synaptically evoked striatal ACh release. Finally, (Aim 3) will selectively rescue SAPAP3 expression in ChIs to test if this model’s disrupted striatal ACh release and OCD-like phenotype are intrinsically driven by SAPAP3-deletion in these cells. This will inform whether ChI-targeted therapies may be sufficient to modify this OCD-like circuit and behavioral phenotype.