Hemoglobin Switching: Genetics to Translation

血红蛋白转换：遗传学到翻译

• 批准号: 8205184
• 负责人: STUART H ORKIN
• 金额: $ 42.91万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-15 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8205184
• 关键词: Address; Adult; Affect; Biological Assay; CCND1 gene; CD34 gene; Development; Developmental Biology; Disease; Erythroid; Erythroid Cells; Erythropoiesis; Fetal Hemoglobin; Genes; Genetic; Genetic Transcription; Goals; Grant; Hemoglobin; Human; Individual; Knowledge; Lead; Libraries; Maps; Methods; Morbidity - disease rate; Open Reading Frames; Pathway interactions; Patients; Regulation; Regulatory Element; Research; Resolution; Route; Screening procedure; Sickle Cell Anemia; Therapeutic; Translating; Translations; Work; base; beta Thalassemia; effective therapy; fetal; genome-wide; global health; improved; mortality; novel; novel therapeutics; progenitor; small hairpin RNA; small molecule; treatment strategy

The global health burden ofthe major hemoglobin disorders, sickle cell anemia and B-thalassemia, is enormous and predicted to grow. Increased fetal hemoglobin (HbF) greatly ameliorates the morbidity and mortality of these disorders. A long sought goal is directed reactivation of HbF expression in adults with hemoglobin disorders. Largely through human genefic studies, substantial progress has been made in understanding the regulatory factors controlling the fetal (a2Y2) to adult (a2B2) switch and how HbF silencing is maintained in the adult. A premise of the proposed work is that fundamental findings on hemoglobin switching provide a platform for establishing mechanism-based approaches to the identification of small molecules that induce HbF in adult erythroid cells. If successful in this overall goal, new therapies may be developed for treatment of patients with the major hemoglobin disorders. This proposal encompasses three independent, but interrelated, aims. First, the mechanisms by which the gene encoding BCL11A, a central repressor of HbF expression, is regulated will be explored using high-resolution nascent transcription mapping, chromafin occupancy, and assays of putafive cis-regulatory elements. Down-regulafion of BCL11A expression or function provides a direct route to relief from HbF silencing. An addifional goal of this aim is also to determine how genefic variafion in the BCL1 IA gene influences expression of BCL11A itself, as this knowledge may lead to approaches to direct down-regulafion of BCL11A expression. Second, highthroughput screening for small molecule inducers of HbF will be performed in cultured erythroid cells, and promising "hits" will be evaluated further for the pathways affected and for optimization as therapeutics. Third, screens with genome-wide short hairpin RNA (shRNA) and open reading frame (ORF) libraries will be performed to identify novel genes/pathways for induction of silenced HbF in primary human CD34 derived erythroid progenitors. Through the mulfidisciplinary approaches in this proposal basic findings on HbF regulation will be translated to advance identificafion and development of new therapeutics for pafients with hemoglobin disorders.

主要血红蛋白疾病、镰状细胞性贫血和 B 地中海贫血给全球健康造成的负担是巨大的，而且预计还会增加。胎儿血红蛋白 (HbF) 的增加大大降低了这些疾病的发病率和死亡率。长期寻求的目标是在患有血红蛋白疾病的成人中直接重新激活 HbF 表达。主要通过人类基因研究，在以下方面取得了实质性进展： 了解控制胎儿 (a2Y2) 到成人 (a2B2) 转换的调节因素以及成人中如何维持 HbF 沉默。拟议工作的前提是血红蛋白转换的基本发现为建立基于机制的方法来识别小分子提供了一个平台。 在成人红细胞中诱导 HbF 的分子。如果成功实现这一总体目标，可能会开发出新的疗法来治疗患有主要血红蛋白疾病的患者。该提案包含三个独立但相互关联的目标。首先，编码 BCL11A 的基因（BCL11A）的机制 将使用高分辨率新生转录图谱、染色质占据和假定的顺式调节元件的测定来探索 HbF 表达的阻遏物的调节。 BCL11A 表达或功能的下调提供了缓解 HbF 沉默的直接途径。该目标的另一个目标是 还确定 BCL1 IA 基因的基因变异如何影响 BCL11A 本身的表达，因为这一知识可能导致直接下调 BCL11A 表达的方法。其次，将在培养的红系细胞中进行 HbF 小分子诱导剂的高通量筛选，并且 将进一步评估有希望的“命中”受影响的途径以及优化治疗方法。 第三，将使用全基因组短发夹 RNA (shRNA) 和开放阅读框 (ORF) 文库进行筛选，以确定在原代人 CD34 衍生的红系祖细胞中诱导沉默 HbF 的新基因/途径。通过本提案中的多学科方法，HbF 调节的基本发现将转化为促进血红蛋白疾病患者新疗法的识别和开发。