The roles of mDia2 in membrane remodeling and organelle clearance during reticulocyte formation

mDia2 在网织红细胞形成过程中膜重塑和细胞器清除中的作用

基本信息

批准号：
10597618
负责人：
Peng Ji
金额：
$ 39.43万
依托单位：
NORTHWESTERN UNIVERSITY AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-04-15 至 2025-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10597618
关键词：
Acetylation Actins Affect Anemia Biochemical Biological Assay Biology Cell Cycle Cell Nucleus Cells Cytokinesis Cytoplasmic Protein Data Deacetylase Deacetylation Defect Development Disease Electron Transport Complex III Enzymes Erythroblasts Erythrocyte Transfusion Erythrocytes Erythroid Erythroid Cells Erythropoiesis Functional disorder Generations Genetic Transcription Goals HDAC6 gene Hematopoietic Image In Vitro Knockout Mice Lysine Mass Spectrum Analysis Mediating Mediator Membrane Microfilaments Microscopy Mitosis Modification Mus Organelles Pathway interactions Phosphorylation Play Polymers Post-Translational Protein Processing Process Production Proliferating Protein Family Publishing Regulation Reporting Reticulocytes Rho-associated kinase Role Serum Response Factor Signal Transduction Signal Transduction Pathway Spectrin Techniques Transcriptional Regulation Transplantation Work cell motility genetic technology in vivo insight mouse model mutant non-histone protein novel novel strategies overexpression polymerization protein complex transfusion medicine treatment strategy

项目摘要

PROJECT SUMMARY Mammalian terminal erythropoiesis has been well studied in erythroid lineage commitment and various factors involved in differentiation and proliferation. Relatively little is known in the final steps of terminal differentiation, specifically from enucleation to reticulocyte maturation into red blood cells. Several outstanding questions in this field include what factors regulate the exit of last mitosis of erythroblast for enucleation, how nascent reticulocyte separate from the extruded nucleus, and what signals are involved in regulating the clearance of organelles in reticulocytes. Answers to these questions with mechanistic insights are important not only for our understanding of the basic biology of terminal erythropoiesis and pathophysiology of many red cell-related diseases, but also to provide clues for efficient strategies of in vitro or ex vivo generation of red blood cells in transfusion medicine. In this respect, we have been working on the role of mDia formins in terminal erythropoiesis and our recent novel unpublished findings may help shed light on the clues to these questions. Using a mDia2 hematopoietic-specific knockout mouse model, we revealed that mDia2 controls the motility of the nascent reticulocyte that is required for the detachment of the pyknotic nucleus. Reticulocytes in mDia2 deficient mice are rigid with extended spectrin chains, primarily due to the disrupted actin profilaments. mDia2 deficient reticulocytes also show defects in membrane remodeling and organelle clearance. We further revealed in our preliminary data that Chmp5, one of the major components of the ESCRT III complex, is a novel downstream mediator of mDia2. Our preliminary mechanistic studies indicated that mDia2 regulates the transcriptional activity of serum response factor (SRF) and Chmp5 is a potential novel target of SRF. These results led us to hypothesize that mDia2 regulates the ESCRT III complex to control membrane remodeling and organelle clearance during reticulocyte formation. In this project, we will use in vivo mouse models, transplantation assays, various biochemical assays, and cutting-edge microscopy to study 1) the functional roles of mDia2 in the formation and organelle clearance of reticulocytes. 2) the mechanism of mDia2-SRF- Chmp5 signaling in the regulation of reticulocyte membrane remodeling and organelle clearance, and 3) the post-translational modifications of mDia2 in its roles in reticulocyte maturation. Successful completion of our proposed studies has the potential to open a new field in signaling transduction that modulates enucleation to reticulocyte formation. Understanding the emerging roles of mDia2 as a master regulator of the late stage terminal erythropoiesis will have an important impact in this field as a paradigm.

项目概要哺乳动物终末红细胞生成已在红细胞谱系定型和各种因素方面得到了深入研究参与分化和增殖。对于终末分化的最后步骤知之甚少，特别是从去核到网织红细胞成熟为红细胞。中的几个悬而未决的问题该领域包括哪些因素调节有红细胞最后一次有丝分裂的退出，以及如何新生网织红细胞与挤出的细胞核分离，以及哪些信号参与调节网织红细胞的清除网织红细胞中的细胞器。以机械见解回答这些问题不仅对我们很重要了解终末红细胞生成的基本生物学和许多红细胞相关的病理生理学疾病，而且还为体外或离体产生红细胞的有效策略提供线索输血医学。在这方面，我们一直致力于mDia formins在终端中的作用红细胞生成和我们最近未发表的新发现可能有助于揭示这些问题的线索。使用 mDia2 造血特异性敲除小鼠模型，我们发现 mDia2 控制固缩核分离所需的新生网织红细胞。 mDia2 中的网织红细胞有缺陷的小鼠是僵硬的，血影蛋白链延长，这主要是由于肌动蛋白丝被破坏。直径2 网织红细胞缺陷还表现出膜重塑和细胞器清除方面的缺陷。我们进一步我们的初步数据显示，ESCRT III 复合体的主要组成部分之一 Chmp5 是一个 mDia2 的新型下游介质。我们的初步机制研究表明 mDia2 调节血清反应因子（SRF）和 Chmp5 的转录活性是 SRF 的潜在新靶点。这些结果使我们假设 mDia2 调节 ESCRT III 复合物来控制膜重塑和网织红细胞形成过程中的细胞器清除。在这个项目中，我们将使用体内小鼠模型，移植测定、各种生化测定和尖端显微镜来研究 1) 功能 mDia2 在网织红细胞形成和细胞器清除中的作用。 2）mDia2-SRF的作用机制- Chmp5 信号传导在网织红细胞膜重塑和细胞器清除调节中的作用，以及 3) mDia2 的翻译后修饰在网织红细胞成熟中的作用。顺利完成我们的拟议的研究有可能开辟信号转导的新领域，调节去核网织红细胞形成。了解 mDia2 作为后期主调节器的新兴角色终末红细胞生成作为范例将在该领域产生重要影响。