Mechanisms of HbF Activation by Non-deletional HPFH

非缺失 HPFH 激活 HbF 的机制

基本信息

批准号：
8854128
负责人：
KENNETH R PETERSON
金额：
$ 37.18万
依托单位：
UNIVERSITY OF KANSAS MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-08-15 至 2016-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8854128
关键词：
3-Dimensional Adult Adverse effects Affect African American Amino Acids Binding Binding Sites Biochemical Biological Assay Bone Marrow Cells Cell Culture Techniques Cells Chromatin Chromatin Structure Chromosomes, Artificial, Yeast Clinical Complex Coupled DNA Binding DNA-Binding Proteins Data Deoxyribonuclease I Development Disease Distal EMSA Elements Environment Erythropoiesis Ethylnitrosourea Fetal Hemoglobin Fluorescence-Activated Cell Sorting Functional disorder Gene Activation Gene Expression Gene Silencing Genes Globin Goals Greek Green Fluorescent Proteins Growth Health Hemoglobin F Disease Hereditary Disease Human Hypersensitivity Intercistronic Region Knowledge Label Lead Light Locus Control Region Mass Spectrum Analysis Modeling Modification Molecular Molecular Biology Molecular Conformation Molecular Target Mus Mutagenesis Mutation Mutation Spectra Nature Nucleotides Outcome Study Patients Phenotype Point Mutation Population Process Promoter Regions Protein Binding Proteins Proteomics Reporter Reporting Repression Research Resolution Sickle Cell Anemia Site Stable Isotope Labeling Staging Stem cells Structure Switch Genes Testing Therapeutic Transcription Repressor/Corepressor Transgenes Transgenic Mice Up-Regulation base beta Globin effective therapy embryo/fetus fetal gene interaction gene repression hematopoietic tissue histone modification in vivo melting mutant new therapeutic target novel prevent promoter protein complex targeted treatment transgene expression

项目摘要

DESCRIPTION (provided by applicant): Understanding the molecular mechanisms underlying the human γ- to β-globin gene switch has long been recognized as important in the treatment of sickle cell disease (SCD), since a wealth of evidence has demonstrated that increased fetal hemoglobin (HbF) significantly decreases the pathophysiology associated with this disease. Thus, knowledge of how to reactivate γ-globin (HbF) in adult erythropoiesis will benefit SCD patients. Our goal in this study is to understand γ-globin gene silencing during the adult stage of definitive erythropoiesis. Our clinical goal is to identify new molecular targets based on the outcome of this study that can be modulated therapeutically for up-regulation of γ-globin synthesis to treat SCD. Non-deletional hereditary persistence of fetal hemoglobin (HPFH) point mutations are likely to be highly informative regarding mechanisms of γ-globin gene repression and activation, but to date have not been studied extensively at the mechanistic level. The proposed study will test the hypothesis that HPFH mutations prevent silencing or maintain activation of γ-globin gene expression by abrogating recruitment of transcriptional repressor complex ("repressosome") components normally located at the γ-globin gene or more distal intergenic regions of the locus, or alternately, by creating a favorable chromatin structure that allows the γ-globin genes to partly outcompete the β-globin gene for interaction with the locus control region (LCR), or both. Several HPFH mutations have been introduced into our human β-globin locus yeast artificial chromosome (β-YAC) including the -566, -195, -175, and -117 , Aγ-globin non-deletional HPFH point mutations and transgenic mice have been produced. In Specific Aim 1, we will study the mechanisms by which the - 566, -195, -175, and -117 HPFH mutations disrupt γ-globin gene repression and/or alter the β-globin locus chromatin domain during development in vivo using murine models and molecular biology/biochemical approaches including transgene structure/expression studies, 3C, histone modification, DNase I sensitivity, co-activator/repressor recruitment, Bcl11A recruitment, and synergy between the HPFH mutations. In Specific Aim 2 we will examine how these four HPFH mutations alter DNA-binding protein complexes in the Aγ-globin promoter using proteomics of isolated chromatin segments (PICh) and Stable Isotope Labeling by Amino Acids in Cell Culture (SILAC) coupled with mass spectrometry (MS). In Specific Aim 3, we will generate and identify novel HPFH mutations within the Aγ-globin gene promoter using a cell-based reporter assay to select for HPFH mutations, followed by phenotypic characterization of these mutations in β-YAC transgenic mice and determination of the DNA-binding activity at these sites. The knowledge we gain from these studies will reveal novel therapeutic targets for which highly-specific treatments may be developed to increase HbF for the treatment of SCD without the side-effects associated with broad-spectrum therapies.

描述（由适用提供）：了解人γ-至β-蛋白质基因开关的分子机制长期以来一直被认为是对镰状细胞疾病（SCD）的重要性，因为大量证据表明，胎儿血红蛋白（HBF）的增加显着降低了与这种疾病相关的病理生物学。这是关于如何重新激活成人红细胞生成的γ-球蛋白（HBF）的知识将使SCD患者受益。我们在这项研究中的目标是了解最终红细胞生成的成人阶段γ-球蛋白基因沉默。我们的临床目标是根据这项研究的结果鉴定新的分子靶标，该靶标可以在治疗上调节以上调γ-球蛋白合成以治疗SCD。胎儿血红蛋白（HPFH）点突变的非缺血遗传持续性可能在γ-珠蛋白基因表达和激活的机制方面具有很高的信息，但迄今为止尚未在机械水平上进行广泛的研究。拟议的研究将检验以下假说：HPFH突变通过废除正常位于γ-糖基因基因或更多离散的当地的crout crout的人类群中，通过废除转录复制子复合物（“抑制体”）组成的转录复制器复合物（“抑制体”）的募集来防止沉默或保持γ-全珠蛋白基因表达的激活，或β-珠蛋白基因座酵母菌人工染色体（β -YAC）（包括-566，-195，-175和-117，Aγ-珠蛋白非缺血HPFH点突变和转基因小鼠）。 In Specific Aim 1, we will study the mechanisms by which the - 566, -195, -175, and -117 HPFH mutations disrupt γ-globin gene expression and/or alter the β-globin locus chromatin domain during development in vivo using murine models and molecular biology/biochemical approaches including transformation structure/expression studies, 3C, histone modification, DNase I sensitivity, HPFH突变之间的共同激活剂/阻遏物募集，BCL11A募集和协同作用。具体目的2我们将研究这四个HPFH突变如何使用分离的染色质片段（PICH）的蛋白质组学（PICH）（PICH）和稳定的同位素在细胞培养物（SILAC）与质谱（MS）中偶联的细胞培养物（SILAC）中通过氨基酸标记的蛋白质组学改变DNA结合蛋白复合物。在特定的目标3中，我们将使用基于细胞的报告基因测定法生成和鉴定Aγ-珠蛋白基因启动子内的新型HPFH突变，以选择HPFH突变，然后在这些位点对这些突变的表型表征以及对这些位置的DNA结合活性的表型表征。我们从这些研究中获得的知识将揭示出新的治疗靶标，可以开发出高度特定的治疗方法，以增加HBF治疗SCD，而无需与广谱疗法相关的副作用。