Regulation of hematopoiesis by ribosomal protein paralogs

核糖体蛋白旁系同源物对造血的调节

• 批准号: 10333363
• 负责人: DAVID L. WIEST
• 金额: $ 56.1万
• 依托单位: RESEARCH INST OF FOX CHASE CAN CTR
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-18 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10333363
• 关键词: Ablation; Acute Myelocytic Leukemia; Address; Adult; Anemia; Attenuated; B-Lymphocytes; Binding; Biogenesis; Biological Process; Biology; Dependence; Development; Disease; Disease Progression; Distal; Dysmyelopoietic Syndromes; Embryo; Erythroid; Functional disorder; Future; Gene Expression; Gene Proteins; Health; Hematologic Neoplasms; Hematopoiesis; Hematopoietic; Hematopoietic Stem Cell Transplantation; Hematopoietic stem cells; Human; Hydroxyeicosatetraenoic Acids; In Vitro; Knowledge; Ligands; Link; Lipids; Lipoxygenase; Malignant Neoplasms; Mediating; Mediator of activation protein; Messenger RNA; Metabolism; Myelogenous; Pathway interactions; Play; Positioning Attribute; Process; Protein Biosynthesis; RNA; RNA Binding; RNA Splicing; RNA Stability; Regulation; Repression; Ribosomal Proteins; Ribosomes; Role; Signal Transduction; Specificity; Stem Cell Development; T-Cell Development; Testing; Therapeutic; Tissues; Translations; Zebrafish; antagonist; arachidonate; attenuation; cancer immunotherapy; cell behavior; combinatorial; experimental study; falls; fatty acid oxidation; fetal; hematopoietic stem cell emergence; hematopoietic stem cell self-renewal; hnRNP A1; immune checkpoint blockade; insight; link protein; loss of function; mouse model; novel; novel strategies; novel therapeutic intervention; paralogous gene; progenitor; protein function; reconstitution; stem cell biology; stem cell function

PROJECT SUMMARY/ABSTRACT Ribosomal proteins (RP) are increasingly understood to play crucial regulatory roles in development and disease; however, the way they do so remains unclear. The potential modes of RP action fall into two classes: effects on the ribosome itself or extraribosomal functions carried out while physically separate from the ribosome. Traditional loss-of-function approaches to address RP function fail to distinguish these modes of action because most RP are essential for ribosome biogenesis and/or function and so ablation of such RP genes attenuates both modes of action. Consequently, an unequivocal determination of the contributions of extraribosomal RP functions to biological processes remains a critical gap in knowledge. Importantly, we have identified an RP, Rpl22, which is not required for ribosome biogenesis or function, but nevertheless plays critical, selective roles in hematopoiesis. Rpl22 not only regulates hematopoietic stem cell (HSC) emergence in the embryo but also regulates adult HSC function, as well as more distal stages of hematopoiesis including B and T lymphocyte development. The basis for the selective requirement for Rpl22 in particular hematopoietic processes remains unclear; however, we have recently determined that the capacity of Rpl22 to regulate fetal HSC emergence is dependent upon its physical association with hnRNP-A1, which can regulate translation. Moreover, hnRNP-A1 selectively associates with Rpl22 molecules that are physically separate from the ribosome. Consequently, we have an unprecedented opportunity to investigate the importance of the extraribosomal function of Rpl22 in hematopoiesis. We hypothesize that Rpl22 regulates hematopoiesis chiefly through its extraribosomal activity, by associating with hnRNP-A1, and regulating the translation, splicing and possibly the stability of RNA targets that differ depending on the cellular context. Indeed, while Rpl22 controls fetal HSC emergence by regulating the expression of Smad1, Rpl22 controls adult HSC behavior by regulating the expression of a lipoxygenase (Alox12), which generates lipid species that activate PPARd, a master regulator of fatty acid oxidation (FAO). As FAO has been shown to regulate HSC self-renewal, we hypothesize that Rpl22 regulates Alox12 signaling to maintain HSCs. In this proposal, we will test these hypotheses in two aims. Aim 1 seeks to determine how the Rpl22/hnRNP-A1 axis exerts its functions in controlling HSC biology, and identify the specific Rpl22-regulated fetal and adult hematopoietic processes that depend on Rpl22 association with hnRNP-A1. Aim2 focuses on investigating the mechanism and role of downstream Alox12-driven FAO pathways through which Rpl22 controls adult HSC function. In pursing these studies, we will integrate cutting edge structural analysis with the unique strengths of zebrafish and a variety of novel mouse models, and verify core findings in human progenitors. Together, these studies will provide the first insight into the novel, extraribosomal “moonlighting” functions through which RP regulate biological processes, and may reveal the basis for the tissue specificity of Rpl22- dependence displayed by particular hematopoietic processes.

PROJECT SUMMARY/ABSTRACT Ribosomal proteins (RP) are increasingly understood to play crucial regulatory roles in development and disease; however, the way they do so remains unclear. The potential modes of RP action fall into two classes: effects on the ribosome itself or extraribosomal functions carried out while physically separate from the ribosome. Traditional loss-of-function approaches to address RP function fail to distinguish these modes of action because most RP are essential for ribosome biogenesis and/or function and so ablation of such RP genes attenuates both modes of action. Consequently, an unequivocal determination of the contributions of extraribosomal RP functions to biological processes remains a critical gap in knowledge. Importantly, we have identified an RP, Rpl22, which is not required for ribosome biogenesis or function, but nevertheless plays critical, selective roles in hematopoiesis. Rpl22 not only regulates hematopoietic stem cell (HSC) emergence in the embryo but also regulates adult HSC function, as well as more distal stages of hematopoiesis including B and T lymphocyte development. The basis for the selective requirement for Rpl22 in particular hematopoietic processes remains unclear; however, we have recently determined that the capacity of Rpl22 to regulate fetal HSC emergence is dependent upon its physical association with hnRNP-A1, which can regulate translation. Moreover, hnRNP-A1 selectively associates with Rpl22 molecules that are physically separate from the ribosome. Consequently, we have an unprecedented opportunity to investigate the importance of the extraribosomal function of Rpl22 in hematopoiesis. We hypothesize that Rpl22 regulates hematopoiesis chiefly through its extraribosomal activity, by associating with hnRNP-A1, and regulating the translation, splicing and possibly the stability of RNA targets that differ depending on the cellular context. Indeed, while Rpl22 controls fetal HSC emergence by regulating the expression of Smad1, Rpl22 controls adult HSC behavior by regulating the expression of a lipoxygenase (Alox12), which generates lipid species that activate PPARd, a master regulator of fatty acid oxidation (FAO). As FAO has been shown to regulate HSC self-renewal, we hypothesize that Rpl22 regulates Alox12 signaling to maintain HSCs. In this proposal, we will test these hypotheses in two aims. Aim 1 seeks to determine how the Rpl22/hnRNP-A1 axis exerts its functions in controlling HSC biology, and identify the specific Rpl22-regulated fetal and adult hematopoietic processes that depend on Rpl22 association with hnRNP-A1. Aim2 focuses on investigating the mechanism and role of downstream Alox12-driven FAO pathways through which Rpl22 controls adult HSC function. In pursing these studies, we will integrate cutting edge structural analysis with the unique strengths of zebrafish and a variety of novel mouse models, and verify core findings in human progenitors. Together, these studies will provide the first insight into the novel, extraribosomal “moonlighting” functions through which RP regulate biological processes, and may reveal the basis for the tissue specificity of Rpl22- dependence displayed by particular hematopoietic processes.