Epigenetic Therapy and Prader-Willi Syndrome

表观遗传疗法和普瑞德威利综合征

基本信息

批准号：
10171492
负责人：
YONG-HUI JIANG
金额：
$ 55.57万
依托单位：
YALE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-10-16 至 2024-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10171492
关键词：
Affect Bioavailable Biological Availability Biology Candidate Disease Gene Cells Chemicals Chimeric Proteins Chromatin Chromosome Structures Chromosomes Clinical Clinical Trials Collaborations Complex DNA Methylation Defect Development Disease Drug Kinetics Drug Screening Embryo Epigenetic Process Exhibits Experimental Designs Fibroblasts Gene Expression Regulation Gene Silencing Gene-Modified Genes Genetic Diseases Genetic Transcription Genetic study Genomic Imprinting Goals Grant Histones Human Human Genetics In Vitro Individual Introns Investigation Lead Libraries Lysine Manuscripts Mediating Medical Genetics Medicine Methylation Methyltransferase Modeling Molecular Molecular Analysis Molecular Genetics Molecular Target Mus Nature Neuraxis Oral Patients Penetration Perinatal mortality demographics Pharmaceutical Chemistry Pharmaceutical Preparations Pharmacology Phenotype Positioning Attribute Prader-Willi Syndrome Process Property Quality of life RNA Regulation Reporting Research SNRPN Safety Small Nucleolar RNA System Testing Therapeutic Therapeutic Intervention Toxic effect UBE3A gene Untranslated RNA acute toxicity analog base chromatin modification disability drug candidate drug development drug use screening epigenetic drug epigenetic regulation epigenetic silencing epigenetic therapy histone methyltransferase histone modification imprint improved in vivo inhibitor/antagonist innovation insight mouse model neurobehavioral disorder novel promoter protein complex screening small molecule targeted treatment

项目摘要

SUMMARY Like most genetic disorders, no specific therapeutic intervention targets the molecular defect of Prader-Willi syndrome (PWS), a genomic imprinting and neurobehavioral disorder that significantly affects the quality of life of affected individuals. PWS is caused by paternal deficiency of genes in the chromosome 15q11-q13 region. The corresponding genes on the maternal chromosome are structurally intact, but their transcription is repressed epigenetically. The involvement of epigenetic regulation renders PWS one of the best opportunities to explore molecular therapy. Recent reports indicate that SNORD116, a SnoRNA cluster located between the SNRPN and UBE3A genes, is responsible for key features of PWS. Although DNA methylation and chromatin modifications at the PWS imprinting center (PWS-IC) are believed to regulate the silent expression of PWS genes in the maternal 15q11-q13 region, the exact mechanism remains elusive. Thus, one attractive molecular-based, therapeutic strategy for PWS is to unsilence the expression of paternally expressed PWS genes, primarily SNORD116, from the maternal chromosome. Because SNORD116 is processed from the long noncoding host RNAs initiated from the PWS-IC or Snrpn promoter, we developed a drug screening system using mouse embryonic fibroblasts (MEFs) derived from mice carrying a maternal Snrpn-EGFP fusion protein. In collaboration with Dr. Bryan Roth (consultant for this proposal), Dr. Jiang (PI) screened 9200 small molecules and identified and validated two compounds that can unsilence the expression of both Snrpn and Snord116 in human PWS cells and a PWS mouse model. These compounds are selective inhibitors of histone methyltransferases (HMTs), as defined by Dr. Jin (co-PI), whose research group is a leader in discovering selective inhibitors of HMTs. Interestingly, in contrast with reactivation of SNRPN by DNA methylation inhibitors, these compounds reduced the H3K9 methylation level but did not change DNA methylation of the PWS-IC. These observations together offer new insights and opportunities to investigate the mechanism underlying the imprinted expression of PWS genes. Our central hypothesis is that these compounds unsilence PWS candidate genes by modifying epigenetic complexes in the PWS-IC, which will provide clinical benefits in PWS mouse models. We propose a Chromatin Spreading Model mediated by H3K9 methylation as a mechanism of imprinted regulation of PWS genes. Our long-term goal is to launch a clinical trial using these compounds or their derivatives in human PWS. The complementary expertise and close collaboration between Dr. Jiang (molecular and human genetics of PWS) and Dr. Jin (chemical biology of novel epigenetic drug development) uniquely position them to attain the specific objectives of this study, which are to understand the mechanism by which these compounds unsilence PWS candidate imprinted genes, to evaluate their efficacy and toxicity, and to optimize their drug-like properties. The proposed study is significant because it will provide novel insight into the molecular mechanism underlying genomic imprinting in PWS and lead to the development of a therapeutic intervention for the disease.

概括像大多数遗传疾病一样，没有特定的治疗干预措施针对Prader-Willi的分子缺陷综合征（PWS），一种基因组烙印和神经行为疾病，显着影响生活质量受影响的个体。 PWS是由15q11-Q13染色体中基因的父亲缺乏引起的。母体染色体上的相应基因在结构上是完整的，但它们的转录被抑制表观遗传。表观遗传调节的参与使PWS成为探索的最佳机会之一分子疗法。最近的报告表明，Snord116是一个位于SNRPN和 UBE3A基因负责PW的关键特征。尽管DNA甲基化和染色质修饰据信，在PWS印迹中心（PWS-IC）调节PWS基因在母体15q11-Q13地区，确切的机制仍然难以捉摸。因此，一个有吸引力的基于分子的， PWS的治疗策略是不要阐明亲子表达的PWS基因的表达，主要是 Snord116，来自母体染色体。因为SNORD116是从长的非编码主机处理的从PWS-IC或SNRPN启动子发起的RNA，我们使用鼠标开发了一种药物筛查系统源自携带母体SNRPN-EGFP融合蛋白的小鼠的胚胎成纤维细胞（MEF）。合作与Bryan Roth博士（该提案的顾问），Jiang博士（PI）筛选了9200个小分子并确定了并验证了两种可以在人PWS中使用SNRPN和SNORD116表达的化合物细胞和PWS小鼠模型。这些化合物是组蛋白甲基转移酶（HMTS）的选择性抑制剂，正如Jin（Co-Pi）博士所定义的那样，其研究小组是发现HMT选择性抑制剂的领导者。有趣的是，与DNA甲基化抑制剂对SNRPN的重新激活相反，这些化合物降低了 H3K9甲基化水平，但没有改变PWS-IC的DNA甲基化。这些观察结果提供新的见解和机会来调查PWS烙印的基础机制基因。我们的中心假设是，这些化合物通过修饰表观遗传学来使PWS候选基因 PWS-IC中的复合物将在PWS小鼠模型中提供临床益处。我们提出了染色质通过H3K9甲基化介导的扩散模型作为PWS基因印迹调节的机制。我们的长期目标是使用这些化合物或其衍生物在人类PWS中发起临床试验。这江博士（PWS的分子和人类遗传学）之间的互补专业知识和密切合作 Jin博士（新型表观遗传药物开发的化学生物学）独特地将其定位为这项研究的目的，这些目标是了解这些化合物无源PWS的机制候选基因，评估其功效和毒性，并优化其类似药物的特性。这拟议的研究很重要，因为它将提供对底层分子机制的新见解 PWS中的基因组印记，并导致为该疾病的治疗干预发展。