Genetic mechanisms which control hematopoietic cell migration

控制造血细胞迁移的遗传机制

• 批准号: 7687557
• 负责人: Geoffrey S. Kansas
• 金额: $ 18.88万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-16 至 2012-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7687557
• 关键词: Anabolism; Binding; Blood Cells; Blood Circulation; Blood Vessels; Bone Marrow; Bone Marrow Transplantation; Carbohydrates; Cell Adhesion Molecules; Chemicals; Defect; Deoxyribonuclease I; E-Selectin; Elements; Endothelial Cells; Enzymes; Epigenetic Process; Exhibits; Family; Foundations; Fucose; Future; Gene Expression; Genes; Genetic; Hematopoiesis; Hematopoietic; Hematopoietic stem cells; Homeostasis; Homing; Immune; Immunity; Inflammation; Inflammatory Response; Knockout Mice; Leukocytes; Ligands; Lymphocyte; Maps; Marrow; Mediating; Molecular Genetics; Mus; Neoplasm Metastasis; Neutrophilia; P-Selectin; Pattern; Phenotype; Phosphorylation; Physiological; Play; Polysaccharides; Post-Translational Protein Processing; Process; Regulation; Research; Role; Selectins; Signal Transduction; Solid; Stem cells; Structure; Surface; Testing; Tissues; Transgenes; Transgenic Organisms; Travel; Work; base; cell motility; gain of function; galactoside 3-fucosyltransferase; genetic element; glycosyltransferase; in vivo; lactosamine; migration; novel; progenitor; public health relevance; receptor; research study; response; success; sugar

DESCRIPTION (provided by applicant): Migration of hematopoietic stem cells (HSC) to appropriate microenvironments within the bone marrow is critical to the success of bone marrow transplantation (BMT). Homing of HSC and hematopoietic progenitors both during BMT and during normal homeostasis is controlled in part by selectins, a family of 3 adhesion molecules which are also critical for mature leukocyte recruitment in settings of inflammation, metastasis, and lymphocyte recirculation. In particular, homing of HSC to bone marrow relies on expression of E-selectin and/or P-selectin on bone marrow endothelial cells as an obligate step in entering specialized niches within the marrow. The physiologic ligands for selectins are carbohydrates, and these glycans are formed by the sequential action of a number of glycosyltransferases. The terminal, regulated step in biosynthesis of all selectin ligands is mediated by the 11,3 fucosyltransferase FucT-VII, which adds a fucose residue 11,3 to a sialylated lactosamine precursor to form structures of the type (Neu5Ac(12-3)Gal(21-4)[Fuc(11-3)]GlcNAc-R). These structures constitute essential elements of ligands for selectins. Mice deficient in FucT-VII exhibit neutrophilia, altered hematopoiesis, and severe defects in immune and inflammatory responses, reflecting the broadly critical importance of this enzyme and the diverse set of processes in which selectins participate. The pattern of expression of FucT-VII and the lack of any phenotype unrelated to selectin ligands in FucT-VII null mice suggest that this enzyme is dedicated to function in selectin ligand biosynthesis. Because post-translational modifications such as phosphorylation play no role in the regulation of glycosyltransferase enzymatic activity, the enzymatic activity of glycosyltransferases is controlled primarily, if not exclusively, at the level of gene expression. However, despite the well documented critical importance of FucT-VII for effective hematopoiesis, inflammation and immunity, surprisingly little is known about how expression of the fut7 gene encoding this key enzyme is regulated in different hematopoietic lineages. In this application, we propose experiments to comprehensively identify cis-acting genetic elements which control fut7 gene expression, and to develop a transgenic, genetic complementation gain-of-function approach for testing the functionality of these elements in vivo. These results will provide a solid, long term foundation to unravel transcriptional, genetic, and epigenetic mechanisms which control fut7 gene expression. PUBLIC HEALTH RELEVANCE During a bone marrow transplant, specialized blood cells called stem cells travel through the bloodstream and enter the bone marrow in response to chemical signals from the tissues. This process involves specific sugars on the surface of these stem cells which bind to specific receptors on the blood vessel wall in the bone marrow. Understanding how expression of these sugars is regulated is therefore of high importance to understanding how bone marrow transplantation works as well as related processes.

描述（由申请人提供）：造血干细胞（HSC）迁移到骨髓内适当的微环境对骨髓移植（BMT）的成功至关重要。HSC和造血祖细胞在BMT期间和在正常稳态期间的归巢部分地由选择素控制，选择素是3种粘附分子的家族，其在炎症、转移和淋巴细胞再循环的情况下对于成熟白细胞募集也是关键的。特别地，HSC归巢到骨髓依赖于E-选择素和/或P-选择素在骨髓内皮细胞上的表达，作为进入骨髓内的特化小生境的必要步骤。选择素的生理配体是碳水化合物，并且这些聚糖通过许多糖基转移酶的顺序作用形成。所有选择素配体生物合成中的末端调节步骤均由11，3岩藻糖基转移酶FucT-VII介导，它将岩藻糖残基11，3添加到唾液酸化的乳糖胺前体中，形成类型（Neu 5Ac（12-3）Gal（21-4）[Fuc（11-3）]GlcNAc-R）的结构。这些结构构成了选择素配体的基本元素。缺乏FucT-VII的小鼠表现出嗜中性粒细胞增多、造血功能改变以及免疫和炎症反应的严重缺陷，反映了这种酶的广泛关键重要性以及选择素参与的各种过程。FucT-VII的表达模式和FucT-VII缺失小鼠中与选择素配体无关的任何表型的缺乏表明该酶致力于选择素配体生物合成中的功能。因为翻译后修饰如磷酸化在糖基转移酶酶活性的调节中不起作用，所以糖基转移酶的酶活性主要（如果不是排他的话）在基因表达水平上被控制。然而，尽管FucT-VII对于有效的造血、炎症和免疫的关键重要性得到了充分的证明，但令人惊讶的是，关于编码这种关键酶的fut 7基因的表达如何在不同的造血谱系中被调节的知之甚少。在这个应用中，我们提出的实验，以全面确定顺式作用的遗传元件，控制fut 7基因的表达，并开发一种转基因，遗传互补获得的功能的方法来测试这些元素在体内的功能。这些结果将为阐明控制fut 7基因表达的转录、遗传和表观遗传机制提供坚实的长期基础。 在骨髓移植过程中，被称为干细胞的特殊血细胞在血液中流动，并响应来自组织的化学信号进入骨髓。这个过程涉及这些干细胞表面的特定糖，这些糖与骨髓中血管壁上的特定受体结合。因此，了解这些糖的表达是如何调节的，对于了解骨髓移植如何工作以及相关过程非常重要。