Germline mutations of PTPN11 (SHP2) in the stem cell microenvironment

项目摘要 努南综合征（NS），一种以先天性心脏病为特征的发育障碍， 面部结构、身材矮小和智力迟钝，是由相关基因的生殖系突变引起的 在Ras信号通路中。NS患者发生白血病的风险增加。的 白血病发生的潜在机制尚未完全了解。NS主要（>50%）与 在蛋白酪氨酸磷酸酶PTPN 11（SHP 2）中存在生殖系杂合激活突变， PTPN 11突变的患者预后最差。我们实验室和其他机构的研究表明， 建立了造血细胞内在PTPN 11突变在NS发病机制中的因果作用， 相关白血病值得注意的是，在上一个资助期，我们发现PTPN 11激活突变 (E76K或D 61 G），特别是表达巢蛋白的细胞和表达巢蛋白的细胞。 衍生的间充质干细胞和骨祖细胞，对发育/ 小鼠模型中血液恶性肿瘤的进展。然而，我们对影响的理解 BM微环境中的PTPN 11疾病突变仍然不完整。我们最近的试点数据表明， 外周神经系统（PNS）和其他神经嵴衍生后代中的PTPN 11激活突变 BM基质中的PTPN 11 E76 K突变也对驻留HSC的神经嵴特异性PTPN 11 E76 K突变产生不利影响 敲入小鼠（PTPN 11 E76 K/+/Wnt 1-Cre+）发生骨髓增生性肿瘤（MPN），并且这种恶性肿瘤 来源于野生型造血干细胞（HSC）。此外，供体细胞来源的MPN（D-MPN） 在移植有健康BM细胞的PTPN 11 E76 K/+/Wnt 1-Cre+小鼠中发展。本报告的总体目标 应用是破译PTPN 11突变在神经系统中的细胞和分子机制， BM基质中的嵴源性细胞诱导MPN。该提案的核心假设是，PTPN 11 这些微环境细胞中的突变直接和/或间接地驱动白血病的发展。 过度激活宿主HSC我们计划测试这一假设，并实现本申请的目标 通过追求以下三个目标。1）。为了鉴定细胞类型、蛋白质因子和/或神经递质， 介导PNS和其他神经嵴衍生物中PTPN 11激活突变的致白血病作用 在BM基质中。2）。为了确定PTPN 11功能获得性激活的分子机制， 突变会放松对PNS和其他神经嵴衍生细胞的活动的调节。3）。验证 BM微环境PTPN 11疾病突变对NS患者标本的致病作用， 患者来源的细胞。这项申请中提出的研究不仅将大大推进我们对 NS白血病发生的机制，但也通知合理设计的新的 预防NS中白血病发展和改善干细胞移植的治疗干预 NS相关血液恶性肿瘤的治疗。

Project Summary Noonan Syndrome (NS), a developmental disorder characterized by congenital heart disease, dysmorphic facial structures, short stature, and mental retardation, is caused by germline mutations in the genes involved in the Ras signaling pathway. Patients with NS are at an increased risk of developing leukemia. The mechanisms underlying the leukemogenesis are not completely understood. NS is mainly (>50%) associated with germline heterozygous activating mutations in the protein tyrosine phosphatase PTPN11 (SHP2), and NS patients with PTPN11 mutations have the worst prognosis. Studies from our laboratory and others have established the causal role of hematopoietic cell intrinsic PTPN11 mutations in the pathogenesis of NS- associated leukemia. Notably, in the last funding period we discovered that PTPN11 activating mutations (E76K or D61G) in the bone marrow (BM) stroma, specifically Nestin-expressing and Nestin-expressing cell- derived mesenchymal stem cells and osteoprogenitors, contributed significantly to the development/ progression of hematological malignancies in mouse models. However, our understanding of the effects of PTPN11 disease mutations in the BM microenvironment is still incomplete. Our recent pilot data indicate that PTPN11 activating mutations in the peripheral nervous system (PNS) and other neural crest-derived progeny in the BM stroma also exert detrimental effects on resident HSCs  neural crest-specific PTPN11E76K mutation knock-in mice (PTPN11E76K/+/Wnt1-Cre+) developed a myeloproliferative neoplasm (MPN), and this malignancy originated from wild-type hematopoietic stem cells (HSCs). Furthermore, a donor cell-derived MPN (D-MPN) developed in PTPN11E76K/+/Wnt1-Cre+ mice transplanted with healthy BM cells. The overall objective of this application is to decipher the cellular and molecular mechanisms by which the PTPN11 mutation in neural crest-derived cells in the BM stroma induce a MPN. The central hypothesis of the proposal is that the PTPN11 mutation in these microenvironmental cells drives leukemia development by directly and/or indirectly hyperactivating resident HSCs. We plan to test this hypothesis and accomplish the objective of this application by pursuing the following three aims. 1). To identify the cell type, protein factors, and/or neurotransmitters that mediate the leukemogenic effect of PTPN11 activating mutations in the PNS and other neural crest derivatives in the BM stroma. 2). To determine the molecular mechanisms by which PTPN11 gain-of-function activating mutations deregulate the activities of the PNS and other neural crest-derived cells. 3). To validate the pathogenic effects of BM microenvironmental PTPN11 disease mutations with NS patient specimens and patient-derived cells. The research proposed in this application will not only greatly advance our understanding of the mechanisms underlying the leukemogenesis in NS, but also inform the rational design of new therapeutic interventions for preventing leukemia development in NS and improving stem cell transplantation therapy for NS-associated hematological malignancies.