Functional and Molecular Dissection of Myeloproliferative Neoplasm Stem Cells

描述(由申请者提供)：候选人Ann Mullally博士提出了一项为期5年的职业发展计划，旨在利用体内小鼠模型研究骨髓增生性肿瘤(MPN)造血干细胞(HSCs)的功能和分子特性，同时建立血液学领域独立内科科学家的学术生涯。本建议的具体目的是：(1)对JAK2V617F突变的HSCs进行详细的功能鉴定；(2)研究TET2缺失对JAK2V617F介导的MPN的影响；(3)确定JAK2V617F突变的HSCs的分子依赖性和协同作用途径。MPN是一种克隆性造血障碍，其特征是成熟血细胞的积聚和相关并发症的发展。JAK2V617F功能获得突变是MPN中最常见的分子异常，重要的是它发生在HSC间隔室。因此，它仍然是MPN的一个有吸引力的治疗靶点，尽管使用小分子JAK2激酶抑制剂直接靶向它的努力到目前为止未能选择性和一致地减少MPN患者中的JAK2V617F突变克隆。这项建议的主要目标是在生物学上了解正常和JAK2V617F突变的造血干细胞之间的差异，并在这样做的过程中，确定MPN干细胞的治疗敏感性，以便它们能够有效地靶向，最终消除维持疾病的MPN克隆。穆拉利博士完全有资格开展这项提议中概述的研究，他最近在《癌细胞》杂志上描述了JAK2V617F突变在小鼠敲打模型中对造血干和祖细胞的不同影响，这将是该提议中所述实验中使用的主要生物试剂。在JAK2V617F敲门小鼠模型的鉴定过程中，穆拉利博士获得了成功完成该提案目标所需的所有技术和方法技能方面的专业知识。候选人在本次K08颁奖期间的主要职业发展目标将是获得成为一名独立医生-科学家所需的额外技能。这将通过候选人执行拟议的研究战略以及参加职业发展计划中概述的一系列正式会议和说教教育活动来实现。此外，这位候选人还组建了一支由导师、顾问和合作者组成的才华横溢的团队，带领她过渡到独立的科学研究人员。她的主要导师本杰明·埃伯特博士非常有能力为这一奖项提供专家指导，因为他拥有HSC生物学、红细胞生成和RNA干扰方面的背景。尽管埃伯特在哈佛的教职级别相对较低，但他已经在学术上取得了非凡的成就，并以对导师的卓越奉献而闻名。此外，候选人将由斯图尔特·奥尔金博士共同指导，他曾指导过70多名在血液学领域非常成功的学术医生和科学家，并在小鼠造血模型方面拥有数十年的经验。她的导师将至少每月与候选人会面，以监督和帮助她过渡到独立。候选人还幸运地继续受益于加里·吉利兰博士的指导和专业知识，他在指导内科科学家走向独立方面有着出色的记录，尽管最近进入了行业，但他仍然非常致力于候选人的职业发展。斯科特·阿姆斯特朗博士将提供更多的小鼠专业知识，他将在候选人的顾问委员会任职，他被公认为白血病干细胞生物学领域的领导者。南希·伯林纳博士和大卫·威廉姆斯博士都是科长，有着长期的指导记录，他们将组成候选人顾问委员会的剩余成员，该委员会将至少每六个月举行一次会议，以确保科学研究项目的成功。最后，候选人招募了罗斯·莱文博士作为她的项目的合作者。莱文博士是描述MPN中JAK2V617F突变的首批科学研究人员之一。

DESCRIPTION (provided by applicant): The candidate, Dr. Ann Mullally, presents a 5-year career development plan that seeks to investigate the functional and molecular properties of myeloproliferative neoplasm (MPN) hematopoietic stem cells (HSCs), using in vivo murine models, while establishing an academic career as an independent physician-scientist in the field of hematology. The specific aims of this proposal are to (1) perform detailed functional characterization of Jak2V617F mutant HSCs; (2) investigate the effect of Tet2 loss on Jak2V617F mediated MPN and (3) determine molecular dependencies and co-operating pathways in Jak2V617F mutant HSCs. MPN are clonal disorders of hematopoiesis characterized by an accumulation of mature blood cells and development of the associated complications of this. The JAK2V617F gain-of-function mutation is the most common molecular abnormality in MPN, and importantly it arises in the HSC compartment. Therefore, it remains an attractive therapeutic target in MPN, although efforts to target it directly using small molecule JAK2 kinase inhibitors have so far failed to selectively and consistently diminish the JAK2V617F mutant clone in MPN patients. The major goal of this proposal is to gain biological understanding of the differences between normal and Jak2V617F mutant HSCs, and in doing so, to identify the therapeutic susceptibilities of MPN stem cells, so that they can be effectively targeted to definitively eliminate the disease-maintaining MPN clone. Dr. Mullally is well qualified to carry out the research outlined in this proposal, having recently described in Cancer Cell, the differential effects of the Jak2V617F mutation on hematopoietic stem and progenitor cells in a murine knockin model, that will be the main biological reagent utilized in the experiments outlined in this proposal. During the course of characterizing the Jak2V617F knockin mouse model, Dr. Mullally gained expertise in all of the technical and methodological skills required to successfully complete the objectives of this proposal. The candidate's primary career development goal during this K08 award period will be to gain the additional skills required to become an independent physician-scientist. This will be achieved through the candidate's execution of the proposed research strategy in addition to her involvement in a series of formal meetings and didactic educational activities as outlined in the career development plan. Furthermore, the candidate has assembled a highly talented team of mentors, advisors, and collaborators to shepherd her transition to independent scientific investigator. Her primary mentor, Dr. Benjamin Ebert is well positioned to provide expert guidance for this award given his background in HSC biology, erythropoiesis and RNA interference. Despite his relatively junior faculty position at Harvard, Dr. Ebert has already achieved remarkable academic success and has established a reputation for exceptional dedication to his mentees. In addition, the candidate will be co-mentored by Dr. Stuart Orkin, who has mentored more than seventy highly successful academic physicians and scientists in the field of hematology and has decades of experience in murine models of hematopoiesis. Her mentors will meet with the candidate at least monthly to supervise and assist in her transition to independence. The candidate is also fortunate to continue to benefit from the guidance and expertise of Dr. Gary Gilliland, who has an outstanding record of mentoring physician-scientists to independence, and although recently moved to industry remains very committed to the candidate's career development. Additional murine expertise will be provided by Dr. Scott Armstrong, who will serve on the candidate's advisory committee, and is recognized as a leader in the field of leukemia stem cell biology. Drs. Nancy Berliner and David Williams, both division chiefs with a long track record of mentorship, will comprise the remaining members of the candidate's advisory committee, which will meet at minimum, every six months to ensure a successful scientific research program. Finally, the candidate has recruited Dr. Ross Levine, one of the initial scientific investigators to describe the JAK2V617F mutation in MPN, as a collaborator for her project.