Molecular and Clinical Glycobiology of the Bone Marrow Environment

血细胞的终生生产需要系统性和系统性指导的造血发展计划 本地信号以传达对这些小区的动态需求。这些信号是如何在延髓内传递的 人们仍然对利基市场知之甚少。由公共关系主任提供的广泛的已公布和即将公布的信息 方案，协作的和单独的，清楚地确立了葡聚糖参与指导 造血祖细胞的命运、功能，尤其是在血小板生成和血小板功能方面。这个 最重要的假说是“细胞内在和外在的糖链介导的机制调节维持， 造血细胞的分化和功能。项目1将调查 半乳糖基转移酶β4GalT1、β1整合素和糖胺多聚糖(GAGS)/硫酸乙酰肝素蛋白多糖 新型组合SHARE在稳态和清髓性应激后的血小板生成中的作用 “组学”和项目3的标准方法：β4GalT1在调节中的未知作用 HSPG的巨核细胞(MK)的表达也将被检测。函数定义的MK偏向 造血干细胞将与项目2一起进行研究，特别是关于重度α2，6- 唾液酸化的细胞表面，尽管缺乏产生这种结构所必需的St6gal1表达。项目 2将研究细胞外糖基化的作用，特别是由外源ST6GAL1介导的作用 结合“组学”方法(项目1)，如何调节造血生态位中的外源性唾液酸化， 确定唾液酸化的细胞表面目标；并通过项目3，了解新发现的 GAG辅因子调节外源性ST6GAL1活性。临床骨髓增生异常综合征(MDS)和 骨髓增生性肿瘤(MPN)和临床前小鼠模型将用于首次评估 这些骨髓疾病的糖生物学表现高度不同，但具有以下共性 巨噬细胞发育异常、血小板数量和功能改变，以及对这些临床疾病的分析是共享的 所有三个项目。项目3将研究GAG与蛋白质的结构-功能关系 在骨髓微环境中，如生长因子及其受体和糖基转移酶。他们的 在促进血栓形成和细胞命运决定中的作用将使用多维方法进行询问 涉及识别不同的GAG序列。项目3将发现合成的Gag模拟物作为 用于治疗的造血/血小板生成。核心A将监督该计划的管理 B将提供从大量RNA样本和单个细胞中提取的cDNA文库的生成和测序，以及 核心C将进行GAG、蛋白质组学和蛋白质-GAG相互作用的比较结构分析，以及 蛋白质表达的定量蛋白质组学。这三个项目紧密交织在一起，将使用所有核心。 这一计划将发现增加血小板生成的新信息，并有助于了解临床 以MK异常为特征的条件。

The life-long production of blood cells requires hematopoietic developmental programs guided by systemic and local signals to convey the dynamic need for these cells. How these signals are delivered within the intra-medullar niches remain poorly understood. Extensive published and to-be-published information by the PIs of this Program, collaborative and individually, clearly established the involvement of glycans in the guidance of hematopoietic progenitor cell fate, function, and especially in thrombopoiesis and platelet functionality. The overarching hypothesis is “cell-intrinsic and extrinsic glycan-mediated mechanisms regulate maintenance, differentiation, and function of hematopoietic cells.” Project 1 will investigate the roles of the galactosyltransferase β4GalT1, β1 integrin, and glycosaminoglycans (GAGs)/heparan sulfate proteoglycans (HSPGs) in thrombopoiesis at steady-state and following myeloablative stress using novel combined shared “omics” and standard approaches with Project 3. A previously unknown role of β4GalT1 to regulate megakaryocyte (MK) expression of HSPGs will also be investigated. A functionally defined MK-biased hematopoietic stem cell will be investigated together with Project 2, especially with respect to the heavily α2,6- sialylated cell surface despite the absence of St6gal1 expression necessary to generate this structure. Project 2 will investigate the role of extracellular glycosylation, especially that mediated by extrinsic ST6GAL1 using the combined “omics” approach (Project 1), how extrinsic sialylation in the hematopoietic niche is regulated, identifying the cell surface targets of sialylation; and with Project 3, understanding how the newly discovered GAG cofactor modulates extrinsic ST6GAL1 activity. Clinical Myelodysplastic Syndromes (MDS) and Myeloproliferative Neoplasms (MPN) and preclinical mouse models will be used in a first-time assessment into the glycobiology of these marrow diseases of highly heterogenous presentations but with the commonality of dysplastic MKs and altered platelet numbers and function, and analysis of these clinical diseases is shared across all three Projects. Project 3 will investigate the structure–function relationships of GAGs with proteins within the marrow microenvironment, such as growth factors and their receptors, and glycosyltransferases. Their roles in promoting thrombopoiesis and cell fate decisions will be interrogated using a multi-dimensional approach to identifying distinct GAG sequences. Project 3 will discover synthetic GAG mimetics as modulators of hematopoiesis/thrombopoiesis for therapeutic use. Core A will oversee the administration of the program, Core B will provide generation and sequencing of cDNA libraries derived from bulk RNA samples and single cells, and Core C will perform comparative structural analysis of GAGs, proteomics and protein-GAG interactions, and quantitative proteomics of protein expression. The three projects are intimately intertwined and will use all Cores. This program will uncover novel information to increase platelet production and help understand clinical conditions characterized by MK abnormalities.