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，红系祖细胞分化为成红细胞，随后去除细胞核和细胞器，发育为成熟红细胞。虽然与红细胞生成的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。已经发现Bcl-2家族成员Nix/Bnip 3L在分化的红系细胞中调节线粒体清除。在缺乏Nix的红细胞中，自噬体的形成正常进行。然而，线粒体进入自噬体的隔离是有缺陷的。提出实验来检验以下假设：Nix调节线粒体靶向进入自噬体以在终末红细胞分化期间清除，并且由于线粒体自噬缺陷而具有线粒体异常保留的红细胞易于氧化应激，导致细胞更新增加和溶血性贫血。目标1.将使用缺乏Nix或自噬的小鼠和红白血病细胞系研究线粒体自噬需要Nix而不是红系成熟的其他方面的假设。目标二。线粒体自噬缺陷的红细胞是否对氧化应激诱导的细胞凋亡更敏感将被检查。目标3.我们将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。已发现红细胞成熟缺陷与贫血有关。通过确定线粒体自噬的分子调控，负责在红细胞成熟过程中的线粒体去除，我们将获得洞察正常和疾病环境下的红细胞生成的调节。这将导致更好地了解与红细胞成熟缺陷相关的血液学疾病的发病机制。它还可以促进治疗这些疾病的治疗方法的发展。公共卫生相关性：该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情况下红细胞生成的调节。拟议的研究可能会导致更好地了解与红细胞成熟缺陷相关的血液疾病的发病机制。

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.