Mechanisms of Impaired Granulopoiesis Due to CLPB Mutations

项目总结/摘要 这项研究的目的是阐明重症先天性巨噬细胞的分子发病机制， 嗜中性粒细胞减少症（SCN）由于酪蛋白分解肽酶B（CLPB）的突变。SCN是一种先天性疾病， 以出生时严重慢性中性粒细胞减少为特征的粒细胞生成，继发于 感染并发症和向骨髓恶性肿瘤的转化。通过一个大的外显子组测序 SCN队列中，候选人最近已确定CLPB中的杂合错义突变为新的 SCN的常见原因CLPB是一种位于线粒体内部的核编码蛋白质 膜空间，在那里它起分子伴侣的作用，以解聚和促进再折叠的蛋白质。 错误折叠的蛋白质然而，将CLPB功能受损与粒细胞缺陷联系起来的机制， 形成不清楚。在这项提案中，主要研究者将测试突变CLPB作为 以显性方式破坏CLPB的伴侣蛋白功能，导致线粒体应激受损 反应和诱导早幼粒细胞凋亡。为了检验这一假设，以下具体目标是 目的：1）确定CLPB突变是否损害线粒体对内质网的反应， 目的2）检查CLPB突变对粒细胞前体细胞中的网状应激的影响， 从糖酵解到早期粒细胞前体的氧化磷酸化。 拟议的研究应提供CLPB的分子病理生理学的理解， 突变SCN。最终，对正常和SCN相关的粒细胞生成的更好理解可能提示新的 治疗或预防SCN患者和接受治疗的患者中的中性粒细胞减少症的治疗方法 清髓性化疗 这位物理学家兼科学家候选人的长期目标是建立一个富有成效和独立的 研究正常和恶性造血的主要学术机构的实验室。主要导师 是丹尼尔林克博士，一位杰出的科学家，他也是一位经验丰富、尽职尽责的导师。一组 具有互补的科学和翻译专业知识的高级研究人员将在正式的K99 导师委员会提供科学和职业指导。华盛顿大学是一个例外 培训初级研究人员的环境，特别是那些对造血感兴趣的人。有现成的通道 拥有众多的核心设施和强大的知识环境，拥有干细胞生物学、中性粒细胞 生物学、线粒体生物学和造血的细胞模型。除了参加课程， 生物统计学和生物信息学，候选人将利用提供的讲习班的广泛组合， 华盛顿大学帮助初级研究人员建立和运营独立实验室。华盛顿 大学已承诺提供实验室空间和资源，以促进候选人的过渡， 独立

Project Summary/Abstract The goal of the proposed research is to elucidate the molecular pathogenesis of severe congenital neutropenia (SCN) due to mutations of caseinolytic peptidase B (CLPB). SCN is an inborn disorder of granulopoiesis characterized by severe chronic neutropenia from birth, premature death secondary to infectious complications, and transformation to myeloid malignancy. Through exome sequencing of a large SCN cohort, the candidate has recently identified heterozygous missense mutations in CLPB as a new and frequent cause of SCN. CLPB is a nuclear-encoded protein that resides within the inner mitochondrial membrane space where it functions as a molecular chaperone to disaggregate and facilitate re-folding of misfolded proteins. However, the mechanisms linking impaired CLPB function to a defect in granulocyte formation are unclear. In this proposal, the principle investigator will test the hypothesis that mutant CLPB acts in a dominant fashion to disrupt the chaperone function of CLPB, resulting in impaired mitochondrial stress responses and induction of apoptosis in promyelocytes. To test this hypothesis, the following specific aims are proposed: Aim 1) to determine whether CLPB mutations impair the mitochondrial response to endoplasmic reticulum stress in granulocytic precursors; Aim 2) to examine the impact of CLPB mutations on the switch from glycolysis to oxidative phosphorylation in early granulocytic precursors. The proposed studies should provide an understanding of the molecular pathophysiology of CLPB- mutant SCN. Ultimately, a better understanding of normal and SCN-related granulopoiesis may suggest new therapeutic approaches to treat or prevent neutropenia in patients with SCN, and in patients receiving myeloablative chemotherapy. The long-term goal of this physician-scientist candidate is to establish a productive and independent laboratory at a major academic institution studying normal and malignant hematopoiesis. The primary mentor is Dr. Daniel Link, a distinguished scientist who is also an experienced and committed mentor. A panel of senior investigators with complementary scientific and translational expertise will serve on a formal K99 mentorship committee to provide both scientific and career guidance. Washington University is an exceptional environment to train junior investigators, especially those interested in hematopoiesis. There is ready access to numerous core facilities and a strong intellectual environment with experts in stem cell biology, neutrophil biology, mitochondrial biology, and cellular models of hematopoiesis. In addition to taking courses in biostatistics and bioinformatics, the candidate will take advantage of the broad portfolio of workshops offered at Washington University to help junior investigators establish and run an independent laboratory. Washington University has committed to providing laboratory space and resources to facilitate the candidate’s transition to independence.