O-fucose Modified Notch as a Regulator of the Hematopoietic Stem Cell Homeostasis

O-岩藻糖修饰的 Notch 作为造血干细胞稳态的调节剂

• 批准号: 8399085
• 负责人: Lan Zhou
• 金额: $ 37.37万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-12-15 至 2016-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8399085
• 关键词: Affect; Animal Model; Binding; Blood; Blood Cells; Bone Marrow; Bone Marrow Stem Cell; CXCL12 gene; Cell Adhesion Molecules; Cell Communication; Cell Cycle; Cell physiology; Chemotaxis; Complex; Coupling; Cues; Cytokine Network Pathway; Defect; Development; Disease; EGF gene; Ensure; Environment; Extracellular Domain; Fucose; Fucosyltransferase 1; Future; Glycolipids; Glycoproteins; Goals; Hematopoiesis; Hematopoietic; Hematopoietic Neoplasms; Hematopoietic stem cells; Homeostasis; Homing; Human Development; Image; Imaging technology; In Vitro; Intrinsic factor; Knockout Mice; Knowledge; Lead; Ligand Binding; Ligand Binding Domain; Ligands; Link; Location; Maintenance; Malignant Neoplasms; Marrow; Mediating; Medicine; Modification; Molecular Models; Mus; Mutation; Natural regeneration; Pathway interactions; Photons; Play; Polysaccharides; Process; Production; Proteins; Research; Role; Signal Pathway; Signal Transduction; Site; Specificity; Stem cell transplant; Stem cells; Stromal Cell-Derived Factor 1; System; Testing; base; cytokine; design; embryonic stem cell; glycosylation; glycosyltransferase; improved; in vivo; intravital microscopy; leukemic stem cell; molecular modeling; mouse model; mutant; notch protein; novel strategies; novel therapeutics; reconstitution; stem cell biology; stem cell niche; stem cell therapy; sugar

DESCRIPTION (provided by applicant): One of the signaling pathways that play pivotal roles in stem cell and hematopoietic homeostasis is the Notch signaling cascade. Notch plays a critical role in many developmental and pathophysiological processes. Mutation or abnormal activation of Notch pathway is linked to a variety of human development disorders and cancers. Notch receptor modification by a sugar molecule, fucose, critically regulates Notch receptor interaction with their counterparts, Notch ligands, and is important for Notch signaling activation. The addition of fucose to Notch receptors are mediated by protein O-fucosyltransferase 1 (Pofut1). Using two mouse models, in which mice are genetically modified to be conditionally deficient either in the expression of all fucose-carrying glycoproteins or glycolipids (FX-/-), or only O-linked fucosyl-glycans present on EGF repeats of a few proteins including Notch (conditional Pofut1-/-), we recently identified a role of O-fucose-modified Notch signaling that is essential for hematopoietic homeostasis as well as a requirement of fucose modification of hematopoietic stem cell (HSC) for their proper location in the bone marrow microenvironment, also called niche. These findings uncovered a unique role of fucose-modified Notch in hematopoiesis and HSC biology. In this study, in order to test the hypothesis that fucose-modified Notch is critical for Notch-ligand interaction- dependent control of HSC homeostasis, we will first define the impact of lack of Notch fucose moieties that are required for ligand binding on HSC homeostasis and blood lineage differentiation by using genetically modified mouse models and mouse embryonic stem cells. We will also assess if Pofut1-deficient HSCs, or HSCs that lack fucose known essential for Notch ligand binding, are displaced in the proper marrow niches by using the cutting edge imaging technology (2-photon intravital microscopy). Then, we will determine the mechanism(s) by which lack of Notch O-fucose causes aberrant HSC homeostasis. We will assess if a disruptive interaction between Notch and its ligand due to the lack of fucose in the ligand binding domain is the main reason that causes aberrant stem cell niche location and abnormal HSC function. Further, we will assess the interaction between Notch pathway with other major adhesion molecules and cytokines that are important for stem cell bone marrow homing and marrow niche lodging. Finally, we will determine the significance of the enhanced fucose modification of Notch in HSC binding with ligand and in HSC marrow homing and lodgment. At the end of these studies, we hope the knowledge we have gained will improve our understanding of the role of Notch glycosylation in stem cell biology, and will form the basis that leads to future studies and development of novel therapeutic maneuvers in stem cell therapy and cancer medicine.

描述（由申请人提供）：在干细胞和造血稳态中扮演关键作用的信号通路之一是Notch信号级联。 Notch在许多发育和病理生理过程中起着至关重要的作用。 Notch途径的突变或异常激活与各种人类发育障碍和癌症有关。通过糖分子，岩藻糖，批判性调节Notch受体与对应物，凹口配体的相互作用，对Notch受体的相互作用进行了修饰，对于Notch信号激活很重要。富含岩藻糖在Notch受体中的添加是由蛋白O藻糖基转移酶1（POFUT1）介导的。使用两种小鼠模型，其中遗传修饰的小鼠在所有携带杂糖糖蛋白的表达中是有条件缺陷的对于造血稳态以及造血干细胞（HSC）的岩藻糖修饰的要求，其在骨髓微环境中的适当位置，也称为NICHE所必需。这些发现在造血和HSC生物学中发现了Fucose修饰缺口的独特作用。在这项研究中，为了检验岩藻糖修饰的缺口对于HSC稳态的缺口相互作用的控制至关重要，我们将首先定义缺乏缺乏Notch Fucuse部分的影响，而Notch Fuccose部分对HSC稳态和血液谱系的结合所需的缺乏对HSC稳态和血液谱系的结合所必需的影响，并通过使用遗传学的修饰小鼠模型和小鼠型号的胚胎模型和血液来分化。我们还将通过使用尖端成像技术（2-光子液液体显微镜）在适当的骨髓壁nir中置换了凹入配体结合至关重要的poFUT1缺陷HSC或缺乏岩藻糖的HSC。然后，我们将确定缺乏缺口O-糖糖会导致异常HSC稳态的机制。我们将评估由于配体结合结构域缺乏岩藻糖的缺乏，导致干细胞生态位位置和异常HSC功能而导致的缺口与其配体之间的破坏性相互作用。此外，我们将评估Notch途径与其他主要粘附分子和细胞因子之间对干细胞骨髓归巢和骨髓小裂储藏至关重要的相互作用。最后，我们将确定HSC与配体以及HSC骨髓归巢和LODEgry在HSC结合中Notch增强的岩藻糖修饰的重要性。在这些研究结束时，我们希望我们获得的知识能够提高我们对缺口糖基化在干细胞生物学中的作用的理解，并将构成导致未来研究和开发干细胞疗法和癌症医学中新型治疗动作的基础。