Role of Cited2 in Hematopoiesis

Cited2 在造血中的作用

• 批准号: 8134372
• 负责人: YU-CHUNG YANG
• 金额: $ 39.25万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-25 至 2013-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8134372
• 关键词: Address; Adult; Apoptosis; Biological; Biological Assay; Biology; Bone Marrow; Cell physiology; Cells; Cellularity; Colony-Forming Units Assay; Competitive Binding; Complex; D-Aspartic Acid; Defect; Development; EP300 gene; Embryo; Family; Fetal Liver; Frequencies; Functional disorder; Gene Expression; Gene Transfer; Genes; Glutamic Acid; Goals; Health; Hematologic Neoplasms; Hematopoiesis; Hematopoietic; Hepatocyte; Hypoxia; In Vitro; Knock-out; Knockout Mice; Knowledge; Laboratories; Lipopolysaccharides; Lymphoid; Maintenance; Mediating; Mediator of activation protein; Microarray Analysis; Molecular; Mus; Myelogenous; Oncogenes; Oxidative Stress; Pathogenesis; Pathway interactions; Phenotype; Play; Polycomb; Pregnancy; Proto-Oncogene Protein c-kit; Regenerative Medicine; Reporter; Resistance; Retroviridae; Reverse Transcriptase Polymerase Chain Reaction; Role; Serum; Signal Transduction; Signaling Molecule; Sorting - Cell Movement; Stem cells; Stimulus; Stress; Tail; Testing; Time; Tissues; Trans-Activators; Transplantation; adult stem cell; base; cell type; cofactor; cytokine; genome-wide; hematopoietic tissue; histone acetyltransferase; in vivo; insight; leukemogenesis; member; mouse model; novel; overexpression; progenitor; reconstitution; research study; retroviral-mediated; stem cell biology; therapeutic development; transcription factor

DESCRIPTION (provided by applicant): Cited2 [CBP/p300-interacting transactivators with glutamic acid (E) and aspartic acid (D)-rich tail 2] is one of the founding members of a new family of transcriptional modulators. My laboratory cloned Cited2 and showed that Cited2 is induced by many cytokines and it is a transforming gene when overexpressed. We generated Cited2 null mice and found that deletion of Cited2 causes embryos to die at mid- to late gestation with several developmental defects. Since Cited2 expression correlates positively with LTR-HSCs activity and induces the expression of Bmi-1, a polycomb group gene necessary for the maintenance and renewal of embryonic and adult stem cells, we studied the role of Cited2 in fetal liver hematopoiesis. Cited2-/- fetal liver displayed significant reduction in the numbers of hematopoietic cells in different lineages. In vitro CFU and in vivo reconstitution studies demonstrate that Cited2 plays an important role in fetal liver hematopoiesis. Consistently, microarray analysis and real-time RT-PCR analyses identified several differentially expressed genes corresponding to HSC and progenitor dysfunction in Cited2-/- fetal liver. We have shown that Cited2 is a negative regulator of HIF-1 in certain tissues during development. More recently, others showed that FoxO3 is activated under hypoxia and inhibits HIF-1-induced apoptosis through Cited2 and decreased expression of Cited2 was found in FoxO triple knockout mice, establishing Cited2 as a downstream target of FoxO transcription factors. Since regional hypoxia in the bone marrow plays an important role in regulating stem cell function and FoxOs are critical mediators of HSC resistance to oxidative stress and maintenance of the HSC pool, we would like to study the crosstalk between Cited2, HIF-1, FoxOs and Bmi-1 in adult hematopoiesis using conditional knockout approach to test the hypothesis that the FoxO/Cited2/HIF-1 pathway and Bmi-1 play an important role in regulating HSC functions. The overall strategy of the application is to first functionally characterize Cited2 knockout phenotypes in adult hematopoietic tissue (Aim 1). This will be followed by two mechanistic studies to understand Cited2 actions. In addition to focusing on specific molecules such as Bmi-1 (Aim 2), FoxO3/HIF-1 (Aim 3) and their associated pathways, a more genome-wide approach will also be undertaken in parallel to uncover novel mechanisms. The proposed studies therefore will advance our knowledge of molecular mechanisms regulating normal and abnormal HSC biology, and thus may offer new insights into the therapeutic development targeting HSC for regenerative medicine and for treatment of different hematological malignancies. PUBLIC HEALTH RELEVANCE: This proposal will not only provide information critical to our understanding of normal hematopoiesis and stem cell biology but also elucidate the complex interplay between transcription factors/cofactors and signaling molecules in vivo, which may provide new clues to the molecular pathogenesis of leukemogenesis and help identify targets for specific therapies.

描述（由申请人提供）：Cited 2 [CBP/p300相互作用反式激活因子与富含谷氨酸（E）和天冬氨酸（D）的尾2]是转录调节因子新家族的创始成员之一。本实验室克隆了Cited 2基因，发现Cited 2基因受多种细胞因子的诱导，并且在过表达时是一个转化基因。我们产生了Cited 2缺失小鼠，发现Cited 2的缺失导致胚胎在妊娠中期至晚期死亡，并伴有几种发育缺陷。由于Cited 2表达与LTR-HSC活性正相关，并诱导Bmi-1（胚胎和成体干细胞维持和更新所必需的多梳组基因）的表达，我们研究了Cited 2在胎肝造血中的作用。引用的2-/-胎肝显示不同谱系的造血细胞数量显著减少。体外CFU和体内重建研究表明，Cited 2在胎肝造血中起重要作用。一致地，微阵列分析和实时RT-PCR分析确定了对应于Cited 2-/-胎肝中HSC和祖细胞功能障碍的几个差异表达基因。我们已经表明，Cited 2是一个负调节HIF-1在某些组织在发展过程中。最近，其他研究表明FoxO 3在缺氧条件下被激活，并通过Cited 2抑制HIF-1诱导的细胞凋亡，并且在FoxO三重敲除小鼠中发现Cited 2的表达减少，确立Cited 2为FoxO转录因子的下游靶点。由于骨髓中的局部缺氧在调节干细胞功能中起重要作用，并且FoxO是HSC抵抗氧化应激和维持HSC库的关键介质，我们希望研究Cited 2、HIF-1、使用条件性敲除方法检测FoxO/Cited 2/HIF-1通路和Bmi-1在成人造血中的作用，以验证FoxO/Cited 2/HIF-1通路和Bmi-1在成人造血中的作用的假设。1在调节HSC功能中起重要作用。本申请的总体策略是首先在功能上表征成年造血组织中的Cited 2敲除表型（目的1）。随后将进行两项机制研究，以了解Cited 2的作用。除了关注特定的分子，如Bmi-1（Aim 2），FoxO 3/HIF-1（Aim 3）及其相关通路外，还将同时采用更全基因组的方法来揭示新的机制。因此，拟议的研究将推进我们对调节正常和异常HSC生物学的分子机制的认识，从而可能为针对HSC的再生医学和不同血液恶性肿瘤的治疗提供新的见解。公共卫生相关性：这一建议不仅将为我们理解正常造血和干细胞生物学提供关键信息，而且还阐明了转录因子/辅因子和信号分子在体内的复杂相互作用，这可能为白血病发生的分子发病机制提供新的线索，并有助于确定特定治疗的靶点。