Identification of Altered Molecular Signature of Down Syndrome iPS Cells

描述（由申请人提供）：本申请涉及广泛的挑战领域（14）干细胞和特定的挑战主题，14-HL-101：通过分析来自定义基因型受影响个体的重编程诱导多能干细胞，开发心脏、血管、肺和血液疾病的分子特征。唐氏综合征（DS）儿童表现出一系列临床异常，包括造血细胞发育异常的显著发生率。多达10%的DS新生儿表现出短暂性骨髓增生性疾病（TMD）的证据，这是一种巨核细胞前体细胞异常增生的疾病。此外，患有TMD的婴儿表现出患白血病的倾向。DS儿童血液学异常的自然史表明，21三体直接和功能上有助于妊娠期间胎儿肝脏造血细胞的异常扩增。与这一假设一致，最近的两项研究表明，患有DS的人胎儿显示出巨核细胞红系祖细胞以及红系和巨核细胞集落形成单位的显著扩增。为了更好地定义整倍体和21三体造血祖细胞之间的分子差异，我们建议比较有和没有DS的个体产生的诱导多能干细胞（iPSC）的基因表达和甲基化谱。此外，我们将比较这两组iPSC的造血分化潜力，作为研究DS对血细胞发育和疾病影响的另一种手段。我们的具体目标是：1）从患有和不患有唐氏综合征的个体产生和表征三体和整倍体iPSC，2）比较未分化的DS和野生型iPSC以及衍生自这些iPSC组的造血祖细胞中的微小RNA和mRNA的表达，以及3）表征DS相对于整倍体iPSC的表观基因组。我们的长期目标是确定我们在21三体细胞中检测到的microRNA、mRNA或甲基化差异中的哪一个有助于DS中异常的造血。 公共卫生相关性：本研究与多种人类疾病相关：1）DS儿童中的一过性骨髓增生性疾病，2）DS儿童中的急性白血病，以及3）人类DS的多种非造血表型。对于复杂的遗传疾病，如唐氏综合征，强大的新方法，包括使用人类iPSC，对于提高我们对疾病分子基础的理解和发现缓解这种疾病症状的新方法绝对至关重要。

DESCRIPTION (provided by applicant): This application addresses broad Challenge Area (14) Stem Cells and specific Challenge Topic, 14-HL-101: Develop molecular signatures for heart, vascular, lung, and blood diseases by profiling reprogrammed induced pluripotent stem cells derived from affected individuals of defined genotypes. Children with Down syndrome (DS) show a spectrum of clinical abnormalities, including a remarkable incidence of abnormal hematopoietic cell development. As many as 10% of newborns with DS show evidence of transient myeloproliferative disorder (TMD), a disease in which megakaryocyte precursor cells proliferate abnormally. Moreover, infants with TMD show a predisposition to leukemia. The natural history of hematologic abnormalities in children with DS suggests that trisomy 21 directly and functionally contributes to aberrant expansion of hematopoietic cells in the fetal liver during gestation. Consistent with this hypothesis, two studies have recently demonstrated that human fetuses with DS show a significant expansion in megakaryocyte erythroid progenitors and in both erythroid and megakaryocytic colony forming units. In order to better define the molecular differences between euploid and trisomy 21 hematopoietic progenitors, we propose to compare gene expression and methylation profiles of induced pluripotent stem cells (iPSCs) generated from individuals with and without DS. In addition, we will compare the hematopoietic differentiation potential of these two groups of iPSCs as another means to study the effect of DS on blood cell development and disease. Our specific aims are: 1) To generate and characterize trisomic and euploid iPSCs from individuals with and without Down syndrome, 2) To compare the expression of microRNAs and mRNAs in undifferentiated DS and wild-type iPSCs and hematopoietic progenitors derived from these groups of iPSCs, and 3) To characterize the epigenome of DS versus euploid iPSCs. Our long-term goal is to determine which of the microRNAs, mRNAs or methylation differences we detect in trisomy 21 cells contribute to aberrant hematopoiesis in DS. PUBLIC HEALTH RELEVANCE: This research is relevant to multiple human diseases: 1) transient myeloproliferative disease in children with DS, 2) acute leukemia in children with DS, and 3) multiple non-hematopoietic phenotypes that characterize human DS. For complex genetic diseases, such as Down syndrome, powerful new approaches, including the use of human iPSCs, are absolutely critical to improve our understanding of the molecular basis of the disease and the discovery of novel approaches to alleviate symptoms of this disease.