Protection of stressed hematopoietic stem cells by the tetraspanin family member CD53

四跨膜蛋白家族成员 CD53 对应激造血干细胞的保护作用

• 批准号: 10581382
• 负责人: LAURA G. SCHUETTPELZ
• 金额: $ 39.13万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-01-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10581382
• 关键词: Address; Agonist; Binding Proteins; Biological Assay; Cell Count; Cell Cycle; Cell physiology; Cell surface; Clonal Expansion; Complex; DNMT3a; Data; Development; Experimental Models; Family; Family member; Genes; Genetic; Goals; Hematopoiesis; Hematopoietic Neoplasms; Hematopoietic stem cells; Homing; Immune response; Immune system; Impairment; Infection; Inflammation; Inflammatory; Integral Membrane Protein; Knockout Mice; Label; Ligation; Mediating; Mus; Mutation; Pathway interactions; Phosphoric Monoester Hydrolases; Pilot Projects; Process; Proliferating; Protein Phosphatase 2A Regulatory Subunit PR53; Proteins; Proteomics; Repression; Repressor Proteins; Research; Risk; Role; Shapes; Signal Transduction; Stimulus; Stress; Systems Development; TP53 gene; Testing; Toll-like receptors; Transcription Repressor; Up-Regulation; age related; cdc Genes; cytokine; epigenome; hematopoietic stem cell quiescence; immune system function; improved; in vivo; leukemic transformation; member; migration; mutant; novel; overexpression; prevent; protein complex; response; response to injury; stem cell function; stressor; therapeutic development; therapeutic target; tool; transcriptome sequencing; transcriptomics

Project Summary/Abstract The goal of this proposal is to understand how the tetraspanin family member CD53 protects hematopoietic stem cells (HSCs) from inflammatory stress. While important for normal immune system function, inflammatory signaling can impair HSC function and promote the development of hematopoietic malignancies. In preliminary data, we identified CD53 as a critical regulator of HSC function in the context of inflammatory stress. CD53 is a member of the tetraspanin family of transmembrane proteins that organize multi-protein networks to regulate a wide variety of cellular processes such as proliferation, migration, and survival. While normally expressed at very low levels in HSCs, CD53 is markedly upregulated in response to multiple stressors including inflammatory cytokines, toll like receptor agonists and mobilizing agents. Using our newly-generated Cd53-/- mouse, we found that loss of CD53 causes a significant reduction in HSC repopulating ability and increased cycling in the face of inflammatory stress. RNA sequencing and proximity labeling studies suggest that CD53 promotes HSC quiescence in response to inflammation via activation of “DREAM,” a transcriptional repressor complex involving the Rb-like family members p107/Rbl1 and p130/Rbl2 that inhibits the expression of cell cycle genes in response to p53 and p21 activation. Based on this data, we hypothesize that CD53 promotes DREAM complex-mediated repression of cell cycle-related genes in HSCs in response to inflammatory stress, thereby promoting HSC quiescence and protecting HSC function. Notably, CD53 expression is markedly increased in HSCs deficient for Tet2 or Dnmt3a. Mutations in these epigenome regulators are commonly associated with age-related clonal hematopoiesis (CH), which involves inflammation-driven expansion of mutant HSCs and increased risk of leukemic transformation. We predict that CD53 may thus promote the clonal advantage of mutant HSCs in CH. Using a combination of proteomic, transcriptomic and in vivo HSC functional tools, we will: 1) Determine the role of CD53 in promoting HSC function in response to inflammatory stimuli; 2) Determine how CD53 regulates HSC cycling and DREAM complex activity; and 3) Determine whether elevated CD53 promotes the clonal advantage of mutant HSCs. We will perform overexpression studies to elucidate the effects of sustained CD53 expression on HSC function, and DREAM knockout mice will be used to determine the role of this complex in mediating the effects of CD53 on HSCs. We will determine the mechanisms by which CD53 regulates HSC cycling and DREAM activation using proximity ligation assays to characterize CD53- interacting partners. Finally, we will perform functional studies and chimeric modeling experiments using Cd53 and Dnmt3a knockout mice to determine whether CD53 promotes the clonal expansion of mutant HSCs. Together, our proposed studies will describe a novel mechanism that enables HSCs to resist inflammatory stress. Ultimately, understanding the mechanisms by which both normal and mutant HSCs resist inflammatory stress is essential to the development of therapeutic strategies to promote healthy HSC function and to prevent the expansion of mutant HSCs in CH.

项目总结/文摘