Molecular Regulation of Erythroid Differentiation

描述（由申请人提供）：在哺乳动物红细胞生成过程中，红细胞祖细胞分化成红细胞，随后细胞核和细胞器被移除，发育成成熟红细胞。虽然与红细胞生成不同阶段相关的形态学变化已被很好地表征，但控制这些过程的精确分子机制仍有待确定。Bcl-2家族成员Nix/Bnip3L已被发现调节红细胞分化过程中的线粒体清除。在缺乏nix的红细胞中，自噬体的形成正常进行。然而，线粒体在自噬体中的隔离是有缺陷的。我们提出实验来验证这样的假设，即在终末红细胞分化过程中，Nix调节线粒体靶向自噬体清除，线粒体自噬缺陷导致线粒体异常保留的红细胞容易发生氧化应激，导致细胞周转增加和溶血性贫血。目的1。线粒体自噬需要Nix，而红细胞成熟不需要其他方面的假设，将在缺乏Nix或自噬的小鼠和红细胞白血病细胞系中进行研究。目标2。线粒体自噬缺陷红细胞是否更容易发生氧化应激诱导的细胞凋亡有待进一步研究。目标3。利用免疫沉淀和蛋白质组学方法研究介导nix诱导的线粒体自噬的下游分子。红细胞成熟缺陷已被发现与贫血有关。通过确定红细胞成熟过程中负责线粒体移除的线粒体自噬的分子调控，我们将深入了解正常和疾病环境下红细胞生成的调控。这将有助于更好地理解与红细胞成熟缺陷相关的血液学疾病的发病机制。它还可能促进治疗这些疾病的治疗方法的发展。公共卫生相关性：本项目旨在研究红细胞成熟过程中线粒体自噬的分子调控。这将有助于深入了解正常和疾病环境下红细胞生成的调节。提出的研究可能会导致更好地理解与红细胞成熟缺陷相关的血液学疾病的发病机制。

DESCRIPTION (provided by applicant): During mammalian erythropoiesis, erythroid progenitors differentiate into erythroblasts, followed by the removal of the nucleus and organelles to develop into mature erythrocytes. Although the morphological changes associated with different stages of erythropoiesis have been well characterized, the precise molecular mechanisms governing these processes remain to be determined. A Bcl-2 family member, Nix/Bnip3L, has been found to regulate mitochondrial clearance in differentiating erythroid cells. In Nix-deficient red blood cells, the formation of autophagosomes proceeded normally. However, the sequestration of mitochondria into autophagosomes was defective. Experiments are proposed to test the hypothesis that Nix regulates the targeting of mitochondria into autophagosomes for clearance during terminal erythroid differentiation, and erythrocytes with abnormal retention of mitochondria due to defective mitochondrial autophagy are prone to oxidative stress, leading to increased cell turnover and hemolytic anemia. Aim 1. The hypothesis that Nix is required for the mitochondrial autophagy, but not other aspects of erythroid maturation, will be studied using mice deficient in Nix or autophagy and erythroleukemic cell line. Aim 2. Whether erythrocytes deficient in mitochondrial autophagy are more susceptible to oxidative stress-induced apoptosis will be examined. Aim 3. Downstream molecules mediating Nix-induced mitochondrial autophagy will be studied using immunoprecipitation and proteomics approach. Defects in erythroid maturation have been found to be associated with anemia. By determining the molecular regulation of mitochondrial autophagy responsible for mitochondrial removal during erythroid maturation, we will gain insights into the regulation of erythropoiesis under both normal and disease settings. This will lead to better understanding of the pathogenesis of hemotological disorders associated with defective erythroid maturation. It may also facilitate the development of therapeutic approaches to treat these disorders. PUBLIC HEALTH RELEVANCE: This project seeks to investigate molecular regulation of mitochondrial autophagy during erythroid maturation. This will help gain insights into the regulation of erythropoiesis under both normal and disease settings. The proposed studies may lead to better understanding of the pathogenesis of hemotological disorders associated with defective erythroid maturation.