Using NIS gene for monitoring Stem Cell Therapies

描述（由申请人提供）：人骨髓来源的干细胞能够在体外广泛增殖而不丧失体外分化潜力。它们代表了遗传性或退行性疾病的一种新的细胞疗法。我们希望研究骨髓间充质干细胞（MSC）和造血干细胞（HSC）之间的相互作用，以确定MSC是否可以通过促进移植而不增加移植物抗宿主病（GVHD）的风险来支持同种异体HSC移植。然而，关于静脉输注人类干细胞的体内分布和存活，以及它们对正常组织功能的贡献，目前还没有足够的信息。到目前为止，无论是临床前研究还是临床研究，都无法在体内实时可靠地跟踪这些输注细胞。在这个应用中，我们建议发展分子成像技术来跟踪静脉输注细胞在体内的多个时间点，以了解它们的分布和增殖。具体来说，我们建议使用Na+/I-同向转运体（NIS）基因作为报告基因，利用放射性碘化物或高锝酸盐作为示踪剂，对人干细胞进行标记，成像其在体内的分布和持久性。NIS是一种内在的膜糖蛋白，介导碘（I-）的活性吸收进入甲状腺滤泡细胞。研究表明，NIS基因转移可以诱导多种细胞对碘的吸收，并且表达外源NIS的异种移植物可以在体内成像。我们之前在MSC和HSC输注以及NIS基因成像方面的经验将确保这个项目的成功。该体内成像技术的发展将使我们对人类干细胞的潜力有更深入的了解。我们将首先测试NIS基因转导的可行性，然后用放射性碘化物或等效物开发成像技术来监测干细胞输注。虽然我们的重点是人类间充质干细胞和造血干细胞，但其他干细胞/祖细胞也可以使用所提出的技术进行研究。这种可用于重复成像的非侵入性方法也将使我们能够将血液学/肿瘤学研究扩展到MSC或其他干细胞移植之外。

DESCRIPTION (provided by applicant): Human bone marrow derived stem cells are able to proliferate extensively in vitro without loss of differentiation potential in vitro. They represent a novel cellular therapy of inherited or degenerative diseases. We want to investigate the interaction between bone marrow derived mesenchymal stem cells (MSC) and the hematopoietic stem cells (HSC) to determine if MSCs could support allogeneic HSC transplantation by facilitating engraftment without increasing the risk of graft versus host disease (GVHD). However, there is insufficient information about in vivo distribution and survival of intravenously infused human stem cells and, their contribution to normal tissue function. Thus far, it has not been feasible to reliably track these infused cells in vivo and in real-time in neither pre-clinical nor clinical studies. In this application, we propose to develop molecular imaging techniques to track intravenously infused cells in vivo at multiple time points to understand their distribution and proliferation. Specifically, we propose to use Na+/I- symporter (NIS) gene as a reporter gene to tag human stem cells for imaging their distribution and persistence in vivo by using radioiodide or pertechnetate as the tracer. NIS is an intrinsic membrane glycoprotein that mediates active iodide (I-) uptake into thyroid follicular cells. It has been shown that NIS gene transfer can induce iodide uptake in a variety of cells and that xenografts expressing exogenous NIS could be imaged in vivo. Our previous experience with MSC and HSC infusion and NIS gene imaging will ensure the success of this project. When developed, the proposed in vivo imaging technology will give us insights into human stem cell's potentials. We will first test the feasibility of NIS gene transduction and then develop the imaging techniques with radioiodide or equivalent for monitoring stem cell infusion. Although our focus is on human MSCs and HSCs, other stem/progenitor cells can also be studied using the proposed technology. This non-invasive approach that can be used for repeated imaging will also enable us to extend our hematology/oncology research beyond MSC or other stem cell transplantation.