Functional Role of Tetraspanin CD82 in Hematopoietic Stem Cell Interaction

 描述（由申请人提供）：造血干/祖细胞（HSPC）与细胞微环境的通讯对于干细胞功能的调节至关重要。尽管它们在临床环境中发挥着重要作用，但我们目前对调控HSPCs贩运及其生态位相互作用的分子线索的理解仍然是基本的。因此，为了改善HSPC移植作为患者的治疗选择，我们确定调控HSPC粘附，运输和再增殖的分子和机制至关重要。本提案的目的是确定分子支架蛋白CD 82如何调节HSPC定位和与骨髓的粘附相互作用，这直接影响HSPC功能。我们将检验CD 82通过调节整合素聚集和小生境粘附来调节HSPC归巢、动员和长期再增殖能力的假设。在特定目标1中，我们将利用我们在超分辨率成像方法和原代人类细胞方面的经验，量化CD 82膜组织的分子分布，并确定对整合素聚集、细胞粘附和归巢的影响。对于特定目标2，我们将使用CD 82 KO小鼠确定CD 82表达的变化如何改变HSPC的骨髓保留、归巢和长期再增殖。这一贡献是重要的，因为我们期望将CD 82鉴定为新的治疗靶点，以改善临床中的HSPC分离和移植功效。此外，我们提出要获得的定量单分子和体内信息的组合以前没有被测量过，这将为CD 82在HSPC粘附/信号传导中的功能带来新的视角。因此，该提议是创新的，因为它将采用组合的实验方法来解决HSPC粘附、骨髓运输和再增殖的问题。通过利用小鼠模型、突变分析、超分辨率成像和原始患者样本，我们将整合分子、生化和形态学信息，以获得对CD 82在调节HSPC/生态位相互作用和α 4 β 1整合素中的作用的多尺度理解。

 DESCRIPTION (provided by applicant): Hematopoietic stem/progenitor cell (HSPC) communication with the cellular microenvironment is critical for the regulation of stem cell functions. Despite their essential role in the clinical setting, our current understanding of the molecular cues that regulate the trafficking of HSPCs and their niche interactions remain rudimentary. Therefore, to improve HSPC transplantation as a treatment option for patients, it is critical that we identify the molecules and mechanisms that regulate HSPC adhesion, trafficking and repopulation. The objective of this proposal is to determine how the molecular scaffold protein, CD82, regulates HSPC localization and adhesive interactions with the bone marrow, which directly influences HSPC function. We will test the hypothesis that CD82 modulates HSPC homing, mobilization, and long-term repopulation capacity through the regulation of integrin clustering and niche adhesion. In Specific Aim 1, we will use our experience with super-resolution imaging methods and primary human cells to quantify the molecular distribution of CD82 membrane organization and determine the effects on integrin clustering, cell adhesion and homing. For Specific Aim 2, we will determine how changes in CD82 expression alter bone marrow retention, homing, and long-term repopulation of HSPCs using the CD82KO mice. This contribution is significant because we expect to identify CD82 as a novel therapeutic target to improve HSPC isolations and transplant efficacy in the clinic. Furthermore, the combination of quantitative single molecule and in vivo information that we propose to obtain has not been measured previously and will bring new perspectives to the function of CD82 in HSPC adhesion/signaling. As such, this proposal is innovative because it will apply a combinatorial, experimental approach to the problem of HSPC adhesion, bone marrow trafficking and repopulation. By utilizing mouse models, mutational analysis, super-resolution imaging, and primary patient samples, we will integrate molecular, biochemical and morphological information to obtain a multi-scale understanding of the role of CD82 in regulating HSPC/niche interactions and the a4ß1 integrin.