Using NIS gene for monitoring Stem Cell Therapies

描述（由申请人提供）：人骨髓源性干细胞能够在体外广泛增殖，而不会丧失体外分化潜能。它们代表了遗传性或退行性疾病的新型细胞疗法。我们想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是否可以支持异基因造血干细胞移植，促进植入，而不增加移植物抗宿主病（GVHD）的风险。然而，关于静脉输注的人干细胞的体内分布和存活及其对正常组织功能的贡献的信息不足。到目前为止，在临床前研究和临床研究中，在体内和实时可靠地跟踪这些输注的细胞还不可行。在本申请中，我们建议开发分子成像技术，以在多个时间点跟踪体内静脉输注的细胞，以了解它们的分布和增殖。具体而言，我们建议使用Na+/I-同向转运体（NIS）基因作为报告基因标记人类干细胞，以成像其分布和持久性在体内使用放射性碘或高锝酸盐作为示踪剂。NIS是一种内源性膜糖蛋白，介导甲状腺滤泡细胞对活性碘（I-）的摄取。已经表明，NIS基因转移可以诱导多种细胞中的碘摄取，并且表达外源性NIS的异种移植物可以在体内成像。我们以前的MSC和HSC输注和NIS基因成像的经验将确保该项目的成功。当开发出来时，所提出的体内成像技术将使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，然后开发放射性碘或等效物的成像技术来监测干细胞输注。虽然我们的重点是人MSC和HSC，但也可以使用所提出的技术研究其他干/祖细胞。这种可用于重复成像的非侵入性方法也将使我们能够将我们的血液学/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.