Using NIS gene for monitoring Stem Cell Therapies

描述(申请人提供)：人骨髓来源的干细胞能够在体外广泛增殖，而不会失去体外分化的潜力。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MSCs是否可以在不增加移植物抗宿主病(GVHD)风险的情况下，通过促进植入来支持异基因HSC移植。然而，关于静脉输注的人类干细胞在体内的分布和存活以及它们对正常组织功能的贡献，信息还不够充分。到目前为止，无论是在临床前还是临床研究中，都不可能在体内和实时可靠地跟踪这些注入的细胞。在这一应用中，我们建议开发分子成像技术来跟踪体内多个时间点的静脉输注细胞，以了解它们的分布和增殖。具体地说，我们建议使用Na+/I-转运体(NIS)基因作为报告基因来标记人类干细胞，以放射性碘或高铁酸盐为示踪剂，以显示其在体内的分布和存留。NIS是一种固有的膜糖蛋白，介导活性碘(I-)进入甲状腺滤泡细胞。已经证明，NIS基因转移可以诱导多种细胞摄取碘，并且表达外源NIS的异种移植瘤可以在体内成像。我们之前在骨髓间充质干细胞和造血干细胞输注以及NIS基因成像方面的经验将确保这个项目的成功。一旦开发出来，拟议的体内成像技术将让我们深入了解人类干细胞的潜力。我们将首先测试NIS基因转导的可行性，然后开发用于监测干细胞输注的放射性碘或类似物的成像技术。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/祖细胞也可以使用拟议的技术进行研究。这种可用于重复成像的非侵入性方法也将使我们的血液学/肿瘤学研究超越骨髓间充质干细胞或其他干细胞移植。

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.