Tissue Culture Models of Lesch-Nyhan Disease

描述（由申请人提供）：尽管已知Lesch-Nyhan病（LND）的潜在基因缺陷，并且基底神经节功能改变与神经和行为异常的表现密切相关，但次黄嘌呤-鸟嘌呤磷酸核糖基转移酶（HPRT）活性缺乏与选择性多巴胺丢失之间的机制联系仍不清楚。HPRT缺陷的细胞模型为理解重要的分子扰动和快速评价潜在的治疗药物提供了一种强大而有效的方法。如在体内观察到的，在啮齿动物多巴胺能细胞系中选择HPRT突变导致细胞多巴胺含量的一致降低。这不能通过随后的HPRT功能恢复来逆转。我们建议利用现有的细胞模型，以及在体外产生多巴胺能神经元的干细胞技术的最新进展，以研究HPRT缺陷所赋予的多巴胺能特异性和分化的改变。了解嘌呤补救和多巴胺稳态之间的联系是解开LND的病理基础的关键，而确定的时间窗口，其中HPRT是正常的多巴胺能张力所需的，提供了一个有意义的基础，有效的治疗方法，特别是基因替代策略的发展。

DESCRIPTION (provided by applicant): Although the underlying gene defect in Lesch-Nyhan Disease (LND) is known and altered basal ganglia function strongly implicated in the manifestation of neurological and behavioral abnormalities, the mechanistic connection between the lack of hypoxanthine-guanine phosphoribosyltransferase (HPRT) activity and selective dopamine loss remains unclear. Cell models of HPRT-deficiency provide a powerful and efficient approach to understanding the important molecular perturbations and rapid evaluation of potential therapeutic agents. As observed in vivo, selection for HPRT mutations in rodent dopaminergic cell lines has resulted in a consistent decrease in cellular dopamine content. This has not been reversible by subsequent restoration of HPRT function. We propose to utilize existing cell models as well as recent advancements in stem cell technology that generate dopaminergic neurons in vitro to investigate alterations in dopaminergic specification and differentiation conferred by HPRT deficiency. Understanding the link between purine salvage and dopamine homeostasis is key to unraveling the pathological basis of LND, while identifying the temporal window wherein HPRT is required for normal dopaminergic tone provides a meaningful basis for the development of effective therapeutics, especially gene replacement strategies.