Hedgehog Treatment of Down Syndrome: Establishing Mechanisms

唐氏综合症的刺猬疗法：建立机制

• 批准号: 8931797
• 负责人: Roger H Reeves
• 金额: $ 19.74万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-22 至 2017-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8931797
• 关键词: Adrenal hormone preparation; Adult; Adverse effects; Affect; Age; Age-Months; Agonist; Anatomy; Antibiotics; Area; Attenuated; Behavior; Biological Assay; Birth; Brain; Brain Part; Brain region; Cell Count; Cell Proliferation; Cells; Cerebellum; Child; Childhood Malignant Brain Tumor; Chromosomes, Human, Pair 21; Clinic; Cognitive; Complementary DNA; Congenital cerebellar hypoplasia; Country; Cytoplasmic Granules; DNA; Data; Development; Dose; Down Syndrome; Down-Regulation; Doxycycline; Drug Delivery Systems; Embryonic Development; Emotional; Epidemiology; Erinaceidae; Evaluation; Exposure to; Family; Gene Expression; Genes; Genetic; Growth Factor; Hippocampus (Brain); Human; Human Cell Line; Human Chromosomes; Injection of therapeutic agent; Intellectual functioning disability; Journals; Laboratories; Learning; Life; Light; Link; Luciferases; Malignant Neoplasms; Maps; Mediating; Medical; Memory; Methods; Mitotic; Morphology; Mothers; Motion; Mus; Mutation; Neonatal; Neural Crest Cell; Neurons; Oncogenic; Orthologous Gene; Performance; Persons; Pharmacology; Physiology; Play; Population; Problem Solving; Process; Production; Prosencephalon; Purkinje Cells; Recovery; Resistance; Role; Series; Signal Transduction; Site; Societies; Sonic Hedgehog Pathway; Structural defect; Structure; Synaptic plasticity; Syndrome; System; Testing; Tetanus Helper Peptide; Therapeutic; Thyroid Hormones; Time; Translating; Trisomy; Validation; Water; biological systems; cDNA Library; cell transformation; combinatorial; cost; dentate gyrus; disability; expression cloning; gene function; genetic approach; granule cell; human SMO protein; improved; in vivo; medulloblastoma; mouse Ts65Dn; mouse model; neonate; neuro-oncology; overexpression; postnatal; programs; promoter; public health relevance; pup; research study; response; restraint; screening; small molecule; smoothened signaling pathway; young adult

 DESCRIPTION (provided by applicant): Down syndrome (DS), caused by trisomy for human chromosome 21 (Hsa21), is the most common genetically defined cause of intellectual disability. Structural abnormalities that are thought to contribute to learning problems are seen in the cerebellum and hippocampus of people with the condition. Treatments to correct these parts of the brain would tangibly improve the lives of children and young adults with DS and would allow them to better integrate into society. We recently showed that a single injection on the day of birth with the Sonic Hedgehog (Shh) agonist, SAG 1.1, permanently normalizes the size and gross anatomy of the cerebellum, leads to better adult spatial problem solving, and restores electrophysiological correlates of learning in the CA1-hippocampal subfield of the Ts65Dn mouse model of DS. A number of questions remain before this finding can be translated to therapy for people. Whether improvements in hippocampal behavior & physiology occur through Shh-induced normalization of cerebellar structure or via direct stimulation with Shh is not known. Another restraint on advancing Shh treatments to the clinic is the very wide range of effects of this potent growth factor, making systemic application in people problematic. A more confined method of drug delivery might limit side effects. Another approach would be to understand which Hsa21 genes act to downregulate the Shh pathway response in cerebellum, which might suggest more "druggable" targets. The experiments proposed here will first screen Shh responses with an Hsa21 Gene Expression clone-set of 169 cDNAs, 149 of which are highly conserved between human and mouse and twenty that are human specific. Genes that significantly decrease Shh pathway activation in the LIGHT2 assay will be evaluated in additional Shh-sensitive assays to assure that they generalize across different biological systems (Specific Aim 1). Next, we will determine how region-specific expression of Shh in the Ts65Dn brain affects hippocampal function. Using a conditional "temporal-spatial" genetics approach that will allow us to increase Shh expression at birth for a 24h period selectively within the Purkinje cells of the cerebellum, or within the hippocampus, we will determine whether cerebellar Shh expression is necessary and/or sufficient to correct the behavior & physiology of adult Ts65Dn mice in hippocampal tests or whether Shh actions in additional parts of the brain are required (Specific Aim 2).

 描述（由申请人提供）：唐氏综合症（DS）由人类 21 号染色体（Hsa21）三体性引起，是智力障碍最常见的遗传原因。患有这种疾病的人的小脑和海马体中出现了被认为会导致学习问题的结构异常。纠正大脑这些部分的治疗将明显改善患有 DS 的儿童和年轻人的生活，并使他们更好地融入社会。我们最近表明，在出生当天单次注射 Sonic Hedgehog (Shh) 激动剂 SAG 1.1，可以使小脑的大小和总体解剖结构永久正常化，从而更好地解决成人空间问题，并恢复 DS65Dn 小鼠模型 CA1 海马亚区学习的电生理相关性。在将这一发现转化为人类治疗之前，仍然存在许多问题。海马行为和生理学的改善是通过“嘘”诱导的小脑结构正常化还是通过“嘘”的直接刺激而发生，目前尚不清楚。将Shh疗法推向临床的另一个限制是这种强效生长因子的作用范围非常广泛，这使得在人体中的全身应用产生了问题。更有限的药物输送方法可能会限制副作用。另一种方法是了解哪些 Hsa21 基因可以下调小脑中的 Shh 通路反应，这可能会提示更多“可药物”靶点。这里提出的实验将首先使用包含 169 个 cDNA 的 Hsa21 基因表达克隆集筛选 Shh 反应，其中 149 个在人类和小鼠之间高度保守，另外 20 个是人类特有的。在 LIGHT2 检测中显着降低 Shh 通路激活的基因将在其他 Shh 敏感检测中进行评估，以确保它们在不同的生物系统中通用（具体目标 1）。接下来，我们将确定 Ts65Dn 大脑中 Shh 的区域特异性表达如何影响海马功能。使用条件“时空”遗传学方法，使我们能够在出生时选择性地在 24 小时内增加 Shh 表达。 在小脑或海马内的浦肯野细胞中，我们将确定小脑 Shh 表达对于纠正海马测试中成年 Ts65Dn 小鼠的行为和生理学是否是必要和/或充分的，或者是否需要大脑其他部分的 Shh 动作（具体目标 2）。