TYORISINE PHOSPHATASE SHP2 IN HEMATOPOIETIC STEM CELL PROPERTY MAINTENANCE

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 这项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。我们将基于我们最近从造血细胞/阶段特异性Shp2缺陷小鼠收集的数据，重点研究包含蛋白酪氨酸磷酸酶Shp2(PTPN11)的Src同源2(SH2)结构域的作用。我们以前产生了一个Ptpn11等位基因，通过Cre-loxP系统诱导Shp2在造血细胞中的缺失会导致骨髓再生不全，造血干细胞(HSC)大量减少，髓系和红系集落形成减少。Shp2突变的小鼠看起来更小，不健康，并且患有严重的贫血。相反，从粒细胞(G)-巨噬细胞(M)前体细胞(GMP)阶段开始就缺乏Shp2表达的小鼠，看起来正常，但随着年龄的增长出现骨量减少。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。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)的共同作用下，Shp2表达缺失的骨髓巨噬细胞(BMM)生长受阻，RAS/ERK激活异常，PI3K/Akt信号转导失控。 我们的初步数据有力地暗示了Shp2在HSC维持和造血中的关键作用，Shp2可能在不同类型的造血细胞和/或不同的造血期具有不同的功能。我们的中心假设是：1)Shp2对HSC的自我更新和/或多谱系分化是必不可少的；2)Shp2是骨髓生成、粒单核细胞增殖和分化所必需的。我们打算填补以下认识空白：1)Shp2缺乏导致的造血缺陷HSC是自主的吗？2)如果是，Shp2在HSC中的作用是什么？Shp2是否在HSC的自我更新、存活和/或多系分化中起作用？3)Shp2调节HSC特性的主要信号通路(S)是什么？4)Shp2缺陷的髓系细胞中Ras/Erk和PI3激酶/Akt信号的缺陷是否导致其生长迟缓，并影响其分化？阐明Shp2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用于再生医学和了解Shp2突变如何导致青少年粒单核细胞白血病(JMML)和髓系增生性疾病(MPD)等人类造血疾病提供深入的认识。

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).