Dopamine D1 Receptor in mouse models of primary dystonia

描述（由申请人提供）：原发性扭转肌张力障碍（PTD）是一组运动障碍，其特征为扭转肌肉挛缩，肌张力障碍是唯一的临床体征（震颤除外），并且不存在神经元变性或后天性原因。有多种遗传原因，具有重叠的表型。我们现在已经确定了一系列的突变GNAL，编码G？olf，在未携带TOR 1A或THAP 1突变的早发性扭转性肌张力障碍（EOTD）患者中。G？olf是一种G蛋白，其将纹状体多巴胺D1（D1 R）和腺苷A2 a（A2 AR）受体与腺苷酸环化酶V偶联。因此，其在纹状体输出中等大小的多刺神经元和胆碱能中间神经元中表达。大量证据支持肌张力障碍中基底神经节的功能障碍，尽管其他区域，例如小脑和皮质，也参与其中。在基底神经节内，重点是多巴胺D2受体（D2 R）和纹状体胆碱能中间神经元。除了酪氨酸羟化酶生物合成途径中的突变之外，GNAL是第一个直接指向DA信号转导系统作为病理生理学起源的EOTD基因，特别是 在D1 R。TorsinA是一种AAA-ATPase蛋白，Thap 1是一种转录因子。然而，它们的具体功能仍然是个谜，特别是它们的突变如何导致肌张力障碍。因此，G？olf和黑质纹状体多巴胺系统允许在三种形式的EOTD的小鼠“模型”中对该系统进行定向的比较测定。这些研究背后的基本原理是，解剖神经传递中的直接效应和代偿性适应不良，特别是多巴胺能和腺苷能，Gnal杂合子缺失小鼠也将为DYT 1（TOR 1A）和DYT 6（THAP 1）EOTD的病理生理学提供线索。在具体目标1中，将确定EOTD基因TOR 1A、THAP 1和GNAL中的突变是否导致纹状体中DA神经传递的类似改变，如DA水平和释放、G蛋白活性和cAMP产生所证明的。在特定目标2中，将在相同基因型中分析基线和干扰素诱导的行为。在D1 R、D2 R和A2 AR受体激动剂和拮抗剂之后，将通过测量ERK和DARPP-32磷酸化的诱导来分析行为的分子对应物。在特定目标3中，将在Gnal+/-小鼠和THAP 1-C54 Y敲入小鼠中进行RNA-seq，并与Tor 1a GAG+/-小鼠中的RNA-seq进行比较（通过合作），以识别下游靶标，特别是神经递质通路中的靶标。在不同形式的EOTD的最终共同途径的鉴定将有助于指导发现这种目前无法治愈的疾病的治疗靶点。

DESCRIPTION (provided by applicant): Primary torsion dystonias (PTD) are a group of movement disorders characterized by twisting muscle contractures, with dystonia as the only clinical sign (except for tremor) and in the absence of neuronal degeneration or an acquired cause. There are multiple genetic causes, with overlapping phenotypes. We have now identified a series of mutations in GNAL, encoding G?olf, in patients with early onset torsion dystonia (EOTD) who do not harbor mutations in TOR1A or THAP1. G?olf is a G protein that couples striatal dopamine D1 (D1R) and adenosine A2a (A2AR) receptors to adenylyl cyclase V. Therefore, it is expressed in striatal output medium size spiny neurons and cholinergic interneurons. Abundant evidence supports dysfunction of the basal ganglia in dystonia, although other regions, e.g. cerebellum and cortex, are also involved. Within the basal ganglia, the focus has been on the dopamine D2 receptor (D2R) and striatal cholinergic interneurons. Other than mutations in the tyrosine hydroxylase biosynthetic pathway, GNAL is the first EOTD gene that directly points to the DA signal transduction system as the origin of pathophysiology, particularly to D1R. TorsinA is a AAA-ATPase protein and Thap1 is a transcription factor. Their specific functions, however, remain enigmatic, particularly as to how their mutations result in dystonia. Therefore, the connection between G?olf and the nigrostriatal dopamine system allows for directed, comparative assays of this system in mouse "models" of the three forms of EOTD. The rationale behind these studies is that dissecting the direct effects and compensatory maladaptations in neurotransmission, particularly dopaminergic and adenosinergic, Gnal heterozygote-null mice will offer clues to pathophysiology in DYT1 (TOR1A) and DYT6 (THAP1) EOTD as well. In Specific Aim 1, it will be determined whether mutations in EOTD genes TOR1A, THAP1 and GNAL result in similar altered DA neurotransmission in the striatum as evidenced by DA level and release, G protein activity, and cAMP production. In Specific Aim 2, baseline and pharmacologically induced behavior will be analyzed in the same genotypes. The molecular counterparts of the behaviors will be assayed via measures of induction of phosphorylation of ERK and DARPP-32, following D1R, D2R, and A2AR receptor agonists and antagonists. In Specific Aim 3, RNA-seq will be performed in the Gnal+/- mouse and THAP1-C54Y knockin mouse, and compared to those in the Tor1a GAG+/-mouse (via collaboration) to identify downstream targets, particularly in neurotransmitter pathways. Identification of a final common pathway in different forms of EOTD will aid in directing discovery of therapeutic targets for this currently incurable disorder.