关键词：异常；贫血；先天性畸形；发病机制
摘 要：Diamond Blackfan Anemia (DBA) is a disorder that results in pure red cell aplasia, congenital abnormalities, and predisposition to cancer. The current treatment of steroids and chronic transfusions leads to significant morbidity. Approximately 25% of patients with DBA have mutations in RPS19. We previously generated a zebrafish model with RPS19 insufficiency that the phenotype is similar to that observed in patients with DBA. We also first described that p53 is upregulated in these fish injected with RPS19 morpholinos. To understand the mechanism by which RPS19 insufficiency leads to defects in erythropoiesis, we identified a p53 target, microRNA34a (miR34a), as being upregulated in human CD34+ fetal liver cells transduced with RPS19shRNA lentivirus. This not only led to decreased erythroid colony formation, but also aberrant erythroid differentiation. We hypothesize that RPS19 insufficiency mediates defects in erythropoiesis through upregulation of p53 and miR34a. To more rigorously test this hypothesis and identify new downstream targets and microRNAs, we propose three specific aims. In Aim 1, we will characterize the role of miR34a in RPS19 insufficient primary human hematopoietic stem cells in vitro. In Aim 2, we will study the role of miR34a in RPS19 insufficient primary human hematopoietic stem cells in vivo. In Aim 3, RNA-seq will be performed to identify novel transcripts and microRNAs that are aberrantly regulated downstream of RPS19 insufficiency in primary human hematopoietic stem cells. These studies will provide new insights into the molecular pathways downstream of ribosomal protein insufficiency in hematopoietic stem cells and potentially new targets for therapy.