The Role of PPM1D in Myeloproliferative Neoplasms

骨髓增生性肿瘤(MPN)是一种慢性血液疾病，与明显的 发病率和死亡率，并有可能进展为骨髓纤维化和急变期。这些疾病 以一系列起源于造血干细胞(HSC)水平的驱动突变为特征， 然而，目前推动疾病进展的机制尚不清楚。MPN的现代治疗方法 在很大程度上不会改变疾病的进程，因此必须破译其潜在的机制 进展，以确定新的，更有效的治疗剂。这项建议的重点是澄清 磷酸酶镁/锰依赖的1D(PPM1D)在MPN中的作用及其作为潜在靶点的评价 防止MPN疾病进展。PPM1D参与了HSCs的维持和分化，并具有 最近发现在MPN患者的子集中发生突变和/或过度表达。初步数据显示 PPM1D突变/过表达导致JAK2突变的MPN克隆的适合度增加， 抑制PPM1D可耗尽MPN HSCs。进一步辨别MPN中PPM1D调节失调的后果 我们将利用涉及初级MPN样本的多管齐下的方法来实现以下目标 诱导多能干细胞(IPSC)系和小鼠模型：(1)PPM1D的作用 JAK2V617F+人造血细胞分子信号转导失调，(2)体内评价 PPM1D过度表达对MPN疾病表型的影响，(3)确定MPN的治疗脆弱性 PPM1D功能异常的MPN细胞。实验将采用各种技术，包括 生化分析、小鼠移植模型、原代造血细胞集落分析、RNA测序 以及转录本的基因分型。该提案还将评估在MPN中靶向PPM1D的新策略。 西奈山伊坎医学院助理教授布里奇特·马塞利诺博士将 在MPN领域的科学领袖Ronald Hoffman博士的指导下完成了这些研究。 她将拥有75%的受保护的研究时间，并将获得完成这些研究所需的资源 学习。作为一个机构，西奈山是促进内科科学家发展的理想选择 学术研讨会和最先进的设施和资源。布里奇特还将有一个咨询委员会 由西奈山的Eirini Papapetrou博士、斯隆·凯特琳癌症纪念馆的Ross Levine博士组成 Weill Cornell医学院Dan Avi Landau博士、生物统计学家Amylou Dueck博士和Heidi博士 梅奥诊所的科西奥雷克。这里概述的职业发展计划将使马塞利诺博士获得科学 她不仅拥有专业知识，而且还提高了手稿和赠款准备方面的技能。这项提议将为Dr。 马塞利诺将实现她发表研究成果的短期目标和发展的长期目标 作为一名内科科学家，并建立了一个独立的研究计划，专注于识别 MPN中的治疗靶点。

Myeloproliferative Neoplasms (MPNs) are chronic hematologic disorders that are associated with significant morbidity and mortality and have the potential to progress to myelofibrosis and a blast phase. These diseases are characterized by a series of driver mutations that originate at the hematopoietic stem cell (HSC) level, however, the mechanisms driving disease progression are currently unclear. Current therapeutics for MPNs largely do not alter the disease course and it is therefore imperative to decipher the mechanisms underlying progression in order to identify new, more effective therapeutic agents. This proposal focuses on elucidating the role of Phosphatase Mg2+/Mn2+ Dependent 1D (PPM1D) in MPNs and evaluating it as a potential target to prevent MPN disease progression. PPM1D is involved in the maintenance and differentiation of HSCs and has recently been found to be mutated and/or overexpressed in a subset of MPN patients. Preliminary data shows that PPM1D mutation/overexpression leads to increased fitness of the JAK2 mutated MPN clone and that PPM1D inhibition depletes MPN HSCs. To further discern the consequences of dysregulated PPM1D in MPNs we will complete the following aims utilizing a multipronged approach involving primary MPN samples, human induced pluripotent stem cell (iPSC) lines and murine models: (1) Delineate the effects of PPM1D dysregulation on molecular signaling in JAK2V617F+ human hematopoietic cells, (2) Assess the in vivo consequences of PPM1D overexpression on MPN disease phenotype, (3) Identify therapeutic vulnerabilities of MPN cells with dysregulated PPM1D function. Experiments will employ a variety of techniques including biochemical assays, murine transplant models, primary hematopoietic cell colony assays, RNA sequencing and genotyping of transcriptomes. This proposal will also evaluate a novel strategy to target PPM1D in MPNs. Dr. Bridget Marcellino, an assistant professor at the Icahn School of Medicine at Mount Sinai, will be completing these studies under the mentorship of Dr. Ronald Hoffman, a scientific leader in the field of MPNs. She will have 75% of protected research time and will be provided the necessary resources to complete these studies. As an institution Mount Sinai is ideal for fostering the development of physician-scientists with academic seminars and state of the art facilities and resources. Bridget will also have an advisory committee consisting of Dr. Eirini Papapetrou at Mount Sinai, Dr. Ross Levine at Memorial Sloan Kettering Cancer Center, Dr. Dan Avi Landau at Weill Cornell Medical College and biostatisticians, Dr. Amylou Dueck and Heidi Kosiorek at Mayo Clinic. The career development plan outlined here will allow Dr. Marcellino to gain scientific expertise as well as increase her skills in manuscript and grant preparation. This proposal will facilitate Dr. Marcellino to achieve both her short term goal of publishing her findings and her long term goals of developing as a physician-scientist and establishing an independent research program focused on identifying novel therapeutic targets in MPNs.