Improving the interaction of hematopoietic stem cells with the perivascular niche to promote engraftment

项目摘要/摘要 造血干细胞(HSC)移植是许多血液疾病和癌症的根治疗法。 然而，这些程序仍然需要优化，以改善患者的预后和存活率。在某种程度上，我们有 由于我们对供者的HSCs如何与受者的骨髓相互作用缺乏了解 移植。这项研究提案试图解决关于细胞的基本问题 造血干细胞与壁龛细胞之间的相互作用。根据我们之前的数据，我们已经表明，利基市场不是 HSC只指示HSC，但HSC也向利基市场传递有启发性的线索。其中包括触发 将周围的内皮细胞重塑成一个“拥抱”HSC的支撑性口袋。为了更好地描述 这种新的细胞结构，我们结合了多种成像方式来产生第一个相关光和 内源性干细胞在其壁龛中的电子显微镜数据。自那以后，我们进行了功能性遗传 为这种结构的形成提供了机械论见解的研究。这些初步结果导致了 美国将追求以下具体目标：1)识别介导EC的HSC衍生的旁分泌信号 重塑以形成HSC的生态位；2)识别粘附性HSC-EC生态位相互作用的机制 这促进了HSC池的信令和稳定扩展。我们将在体内进行基因敲除 和小分子治疗，结合实时成像，以了解HSC之间的动态相互作用 和内皮细胞。然后，我们将把这些结果转化为具有扩展潜力的体外血管利基 移植前的HSCs。最终，我们希望我们的研究将有助于改善临床的造血干细胞移植。 协议。

PROJECT SUMMARY/ABSTRACT Hematopoietic stem cell (HSC) transplantation is a curative treatment for many blood diseases and cancers. However, these procedures still need to be optimized to improve patient outcomes and survival. In part, we have been limited by our poor understanding of how donor HSCs interact with the recipient bone marrow after transplantation. This research proposal seeks to address fundamental questions regarding the cellular interactions between HSCs and niche cells. Based on our previous data, we have shown that the niche not only instructs HSC, but that HSC also transmit instructive cues to the niche. These include triggered remodeling of surrounding endothelial cells into a supportive pocket that “cuddles” the HSC. To better describe this novel cellular structure, we combined multiple imaging modalities to produce the first correlative light and electron microscopy data of an endogenous stem cell in its niche. We have since performed functional genetic studies that provided mechanistic insight into the formation of this structure. These preliminary results have led us to pursue the following Specific Aims: 1) Identify the HSC-derived paracrine signals that mediate EC remodeling to form a niche for HSCs; 2) Identify mechanisms of adhesive HSC-EC niche interactions that promote signaling and stable expansion of the HSC pool. We will perform in vivo genetic knockdown and small molecule treatments, together with live imaging, to understand the dynamic interactions between HSC and endothelial cells. We will then translate these results to an in vitro vascular niche with the potential to expand HSCs prior to transplantation. Ultimately, we hope our studies will lead to improved clinical HSC transplantation protocols.