Diamond-Blackfan Anemia and Ribosomal Protein S19

描述(由申请人提供)： 这一新应用的长期目标是发展对钻石-布莱克凡贫血(DBA)病理生理学的详细机制理解。具体地说，将探索核糖体蛋白S19(RPS19)在DBA正常红细胞生成和紊乱红细胞生成中的作用。拟议研究的基本原理是，尽管已有25%的DBA受试者被证明在RPS19基因的一个等位基因中存在突变，但目前还没有关于该蛋白如何调节红细胞生成的信息。在目前的应用中，我们建议测试关于DBA的病理生理学和RPS19在红细胞生成中的作用的几个假说：i)RPS19在红细胞中运输和/或表达水平的改变导致红细胞生成障碍；ii)涉及RPS19及其结合伙伴的多蛋白复合体的信号转导途径调节红细胞生成；iii)催乳素是体内红细胞生成的调节剂，并且观察到一些DBA受影响的个体对甲氧氯普胺的有益反应是通过这种治疗诱导的催乳素合成和释放。为了实现我们的既定目标，我们设计了一系列研究，具体目标如下。1)研究正常和突变蛋白在红细胞中的亚细胞定位和表达水平，并确定条件性单倍体功能不全是否可以解释DBA的多效性。通过定义RPS19被RNA介导的干扰(RNAi)特异性抑制后祖细胞红系分化的变化，获得对RPS19在红系生成中的作用的见解。2)鉴定RPS19蛋白的结合体，确定RPS19及其结合体的多蛋白复合体是否调控红细胞生成。3)明确催乳素在调节红细胞生成中的作用，从机制上认识甲氧氯普胺治疗DBA的疗效。我们期望所提出的目标的成功实现将为DBA的病理生理学和RPS19在红细胞生成中的作用提供基本的见解。此外，我们希望我们的研究产生的新见解可能会导致开发新的治疗策略，用于治疗出现RPS19基因突变的DBA患者。

DESCRIPTION (provided by applicant): The long-term objective of this new application is to develop a detailed mechanistic understanding of the pathophysiology of Diamond-Blackfan anemia (DBA). Specifically, the role of the ribosomal protein S19 (RPS19) in normal erythropoiesis and in disordered erythropoiesis in DBA will be explored. The rationale for the proposed studies is that although 25% of DBA subjects have been documented to harbor mutations in one allele of the RPS19 gene, there is currently no information on how this protein regulates erythropoiesis. In the present application, we propose to test several hypotheses regarding the pathophysiology of DBA and the role of RPS19 in erythropoiesis: i) altered trafficking and/or expression levels of RPS19 in erythroblasts leads to disordered erythropoiesis; ii) a signal transduction pathway involving a multiprotein complex of RPS19 and its binding partners regulates erythropoiesis; and iii) prolactin is a modulator of in vivo erythropoiesis and that the observed beneficial response to metoclopramide of some DBA affected individuals is through prolactin synthesis and release induced by this treatment. To achieve our stated objectives we have designed a series of studies with the following three specific aims. 1) Study subcellular localization and expression levels of normal and mutant proteins in erythroblasts and determine if conditional haploinsufficiency could account for the pleiotropic character of DBA. Obtain insights into role of RPS19 in erythropoiesis by defining alterations in erythroid differentiation of progenitors following specific inhibition of RPS19 by RNA mediated interference (RNAi). 2) Characterize the binding partners of RPS19 protein and determine if multiprotein complex of RPS19 and its binding partners regulate erythropoiesis. 3) Define the role of prolactin in regulating erythropoiesis and develop mechanistic understanding for the efficacy of metoclopramide in treatment of DBA. We anticipate that successful achievement of the proposed aims will provide fundamental insights into the DBA pathophysiology and the role of RPS19 in erythropoiesis. Furthermore, it is our hope that the new insights generated by our studies might lead to the development of new therapeutic strategies for the treatment of DBA patients presenting with RPS19 gene mutations.