JAK2 signaling in erythropoiesis

红细胞生成中的 JAK2 信号传导

基本信息

批准号：
8710321
负责人：
LILY JUNSHEN HUANG
金额：
$ 38.96万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-09-01 至 2018-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8710321
关键词：
Affect Anemia Biology Blood Cells Blood Substitutes Catalytic Domain ChIP-seq Chromatin Structure Clinical Data Complex Cytokine Receptors Defect Development EZH2 gene Endocytosis Epigenetic Process Erythrocytes Erythrocytoses Erythroid Erythropoiesis Erythropoietin Receptor Etiology Event Exhibits Exons Feedback Functional disorder Funding Gene Expression Gene Targeting Generations Genetic Transcription Goals Granulopoiesis Hematologic Neoplasms Hematopoiesis Hematopoietic High-Throughput Nucleotide Sequencing Human In Vitro Investigation Knowledge Ligands Light Mediating Modeling Molecular Mus Mutation Myeloproliferative disease Pathway interactions Patients Phenotype Phosphorylation Phosphorylation Site Phosphotransferases Play Polycomb Polycythemia Process Production Protein Tyrosine Kinase Proteins Recruitment Activity Regulation Repression Role STAT5A gene Signal Pathway Signal Transduction Stem cells System Testing Therapeutic Agents Toxic effect Translating Work chromatin immunoprecipitation design effective therapy epsin erythroid differentiation gain of function genome wide association study genome-wide granulocyte improved in vitro activity in vivo kinase inhibitor knowledge base mouse model mutant novel novel therapeutics progenitor public health relevance research study stem

项目摘要

DESCRIPTION (provided by applicant): The Janus tyrosine kinase 2 (JAK2) plays an important role in hematopoiesis of multiple lineages, and a gain-of-function JAK2 mutation, V617F, is the major determinant in myeloproliferative neoplasms (MPNs). JAK2 kinase inhibitors showed hematological toxicity in treating MPNs, calling for novel therapeutics that can target only the affected lineage while sparing others. This task is hampered by lack of understanding in how JAK2 signaling regulates the generation of different blood cells. We propose to fill this knowledge gap by determining JAK2 signaling pathways that differentially drive erythropoiesis vs. granulopoiesis, and delineate two novel pathways utilized by JAK2 to regulate signaling and transcription for erythroid differentiation. The overall goal of this proposl is to characterize mechanisms underlying how JAK2 regulates erythropoiesis. Aim 1 will characterize a novel set of murine models; each expresses a different activating JAK2 mutant that results in a distinct MPN phenotype. We will determine whether different JAK2 mutants cause erythrocytosis or granulocytosis by promoting lineage-specific proliferation or by skewing differentiation in common progenitor compartments, and identify downstream signaling pathways required therein to cause different MPN phenotypes. We will also translate these mechanistic studies into the human setting. Aims 2 and 3 will dissect two novel molecular mechanisms for JAK2 to orchestrate signaling and transcription for erythroid differentiation, and examine their contribution in MPN development. Aim 2 will use both in vitro and in vivo experiments to characterize how JAK2 directs endocytosis of the erythropoietin receptor to terminate signaling. This process involves a new function of the p85 subunit of PI3K and is PI3K kinase activity-independent. Defects in this process result in prolonged signaling in primary and familial congenital polycythemia. In Aim 3, we will employ transcriptional profiling and genome-wide chromatin-immunoprecipitation followed by high-throughput sequencing (ChIP-seq) to delineate a novel pathway whereby JAK2 controls transcription, not by the canonical JAK-STAT pathway, but by regulating chromatin structure through phosphorylating the polycomb repression complex 2. Results from these studies will fill key gaps in our understanding of signaling in hematopoietic stem and progenitor cells that regulate both normal and excessive erythropoiesis. These results will also further our understanding of how Epo signaling is terminated, and will shift the paradigm of how JAK2 activates erythroid transcriptional network. In addition, these results will shed light on MPN biology and facilitate the design of novel and more effective therapeutic agents that specifically target affected lineage without compromising other lineages.

描述（由申请人提供）：Janus 酪氨酸激酶 2 (JAK2) 在多个谱系的造血过程中发挥重要作用，功能获得性 JAK2 突变 V617F 是骨髓增生性肿瘤 (MPN) 的主要决定因素。 JAK2 激酶抑制剂在治疗 MPN 时显示出血液学毒性，因此需要新的治疗方法来仅针对受影响的谱系，同时不影响其他谱系。由于缺乏对 JAK2 信号如何调节不同血细胞生成的了解，这项任务受到阻碍。我们建议通过确定差异驱动红细胞生成与粒细胞生成的 JAK2 信号通路来填补这一知识空白，并描述 JAK2 用于调节红细胞分化的信号和转录的两条新通路。该提案的总体目标是描述 JAK2 调节红细胞生成的机制。目标 1 将表征一组新颖的小鼠模型；每个表达不同的激活 JAK2 突变体，导致不同的 MPN 表型。我们将确定不同的 JAK2 突变体是否通过促进谱系特异性增殖或通过在共同祖细胞区室中倾斜分化来引起红细胞增多或粒细胞增多，并确定其中引起不同 MPN 表型所需的下游信号通路。我们还将把这些机制研究转化为人类环境。目标 2 和 3 将剖析 JAK2 协调红细胞分化信号传导和转录的两种新分子机制，并检查它们在 MPN 发育中的贡献。目标 2 将使用体外和体内实验来表征 JAK2 如何指导促红细胞生成素受体的内吞作用以终止信号传导。该过程涉及 PI3K p85 亚基的新功能，并且与 PI3K 激酶活性无关。这一过程的缺陷会导致原发性和家族性先天性红细胞增多症的信号传导时间延长。在目标 3 中，我们将采用转录分析和全基因组染色质免疫沉淀，然后进行高通量测序 (ChIP-seq) 来描绘一条新途径，通过该途径 JAK2 控制转录，不是通过经典的 JAK-STAT 途径，而是通过调节染色质通过磷酸化多梳抑制复合物 2 来形成结构。这些研究的结果将填补我们对造血干细胞和祖细胞信号传导理解的关键空白。调节正常和过度的红细胞生成。这些结果还将进一步加深我们对 Epo 信号传导如何终止的理解，并将改变 JAK2 如何激活红细胞转录网络的范式。此外，这些结果将揭示 MPN 生物学，并有助于设计新颖且更有效的治疗剂，专门针对受影响的谱系，而不损害其他谱系。