TYORISINE PHOSPHATASE SHP2 IN HEMATOPOIETIC STEM CELL PROPERTY MAINTENANCE

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 本研究的长期目标是阐明蛋白酪氨酸磷酸酶在正常造血和造血疾病中的功能。我们将集中在Src同源性2（SH 2）结构域包含蛋白酪氨酸磷酸酶Shp 2（PTPN 11）的作用，根据我们最近从造血细胞/阶段特异性Shp 2缺陷小鼠收集的数据。我们先前产生了Ptpn 11 floxed等位基因，通过“Cre-loxP”系统诱导造血细胞中Shp 2的缺失导致骨髓再生障碍，造血干细胞（HSC）的大量减少以及髓系和红系的集落形成减少。Shp 2突变小鼠看起来更小，不健康，严重贫血。 相比之下，自粒细胞（G）-巨噬细胞（M）祖细胞（GMP）阶段缺乏Shp 2表达的小鼠表现正常，但随着年龄的增长发展成骨质疏松症。 来自这些突变小鼠的骨髓细胞显示CFU-M和CFU-GM集落的数量和大小减少。 缺乏Shp 2表达的骨髓源性巨噬细胞（BMM）在巨噬细胞集落刺激因子（M-CSF）和粒细胞-巨噬细胞集落刺激因子（GM-CSF）的作用下表现出生长迟缓和Ras/Erk活化缺陷，PI 3激酶/Akt信号也被错误调节。 我们的初步数据强烈暗示了Shp 2在HSC维持和造血中的关键作用，并且Shp 2可能在各种类型的造血细胞和/或在不同的造血阶段具有不同的功能。我们的主要假设是：1）Shp 2对于HSC的自我更新和/或多谱系分化是必需的; 2）Shp 2对于骨髓生成、骨髓单核细胞增殖和分化是必需的。 我们打算填补以下知识空白：1）由于Shp 2缺陷HSC的造血缺陷是自主的吗？2)如果是这样，Shp 2在HSC中的作用是什么？Shp 2是否在HSC自我更新、存活和/或多谱系分化中发挥作用？3)Shp 2调节HSC特性的主要信号通路是什么？4)Ras/Erk和PI 3激酶/Akt信号通路的缺陷是否导致Shp 2缺陷型骨髓细胞生长迟缓并影响其分化？阐明Shp 2调节HSC自我更新和多谱系分化的分子和细胞机制将为动员HSC用于再生医学提供见解，并了解Shp 2突变如何导致人类造血系统疾病，如青少年粒单核细胞白血病（JMML）和骨髓增生性疾病（MPD）。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The long term goal of this study is to elucidate the function of protein tyrosine phosphatases in normal hematopoiesis and hematopoietic disorders. We will focus on the role of the Src homology 2 (SH2) domain containing protein tyrosine phosphatase Shp2 (PTPN11) based on our recent data collected from hematopoietic cell/stage-specific Shp2 deficient mice. We previously generated a Ptpn11 floxed allele, inducible deletion of Shp2 in hematopoietic cells via "Cre-loxP" system causes marrow aplasia, substantial reduction of hematopoietic stem cells (HSC) and decreased colony formation of myeloid and erythroid lineages. Shp2 mutant mice appear smaller, not healthy and were severely anemic. In contrast, mice lacking Shp2 expression since granulocyte (G)-macrophage (M) progenitor (GMP) stage, appear normal, but developed osteopetreosis as they aged. Marrow cells from these mutant mice show reduction in the number and size of CFU-M and CFU-GM colonies. Bone marrow derived macrophages (BMM) lacking Shp2 expression display retarded growth and defective Ras/Erk activation in response to both macrophage-colony stimulating factor (M-CSF) and granulocyte-macrophage colony stimulating factor (GM-CSF), PI3 kinase/Akt signaling was mis-regulated as well. Our preliminary data strongly implicate a critical role for Shp2 in HSC maintenance and hematopoiesis, and Shp2 may have differential function in various types of hematopoietic cells and/or at different hematopoietic stage. Our central hypotheses are: 1) Shp2 is essential for the self-renewal and/or multiple lineage differentiation of HSC; 2) Shp2 is required for myelopoiesis, myelomonocytic cell proliferation and differentiation. We intend to fill the following knowledge gaps: 1) Is the defective hematopoiesis due to Shp2 deficiency HSC autonomous? 2) If so, what's the role of Shp2 in HSC? Does Shp2 play a role for HSC self-renewal, survival, and/or multiple lineage differentiation? 3) What is the primary signaling pathway(s) by which Shp2 regulates HSC properties? 4) Does the defective Ras/Erk and PI3 kinase/Akt signaling in Shp2 deficient myeloid cells account for their retarded growth, and affect their differentiation? Elucidating the molecular and cellular mechanism through which Shp2 modulates HSC self-renewal and multi-lineage differentiation will provide insights into mobilizing HSC for regenerative medicine and understanding how Shp2 mutations cause human hematopoietic diseases, such as juvenile myelomonocytic leukemia1 (JMML) and myeloid proliferative disorders (MPD).