In vivo reporters of gene expression

描述（由申请人提供）：器官移植变得越来越普遍，在过去的20年里，由于积极的免疫抑制药物治疗，移植的一年生存率急剧上升。例如，肾移植现在在大多数移植中心一年的成功率超过90%。然而，在同一时期，长期存活率并没有显著增加。亚临床炎症（SCI）是器官移植恶化的主要原因，为了提高器官移植的长期成功率，在移植组织中测量SCI是至关重要的。目前，脊髓损伤的评估是通过活检的侵入性措施，但可以通过炎症期间激活的基因成像更有效地评估。我们已经开发了一个基因表达报告系统，可以用于成像基因表达在深层组织。报告子是由选定的启动子表达的适体，当它们结合靶放射配体时，就会被可视化。适体充当细胞内受体，与它们的配体紧密结合，从而提供启动子被激活的细胞图像。目前的资深团队包括细胞和分子生物学、合成有机化学和放射化学方面的专业知识，他们将开发一种适体报告系统，用于对移植组织的局部炎症进行成像，实现以下具体目标：1)制备稳定表达新霉素适体的哺乳动物细胞，作为调控（Lcn2）或组成型表达（actin）基因的报告者；2)开发合成适体配体的化学方法并对其进行放射性标记；3)在体内对actin和Lcn2基因表达进行成像。这里提出的研究对监测组织移植的健康状况具有广泛的意义，可以在药物治疗方面做出更明智的决定。这种监测预计将增加移植的存活率，这些移植已经被修改了

DESCRIPTION (provided by applicant): Organ transplants are becoming increasingly common and the one year graft survival rates have risen sharply over the past 20 years due to aggressive immunosuppressive drug treatments. For example, renal transplants now have one year success rates of over 90% in most transplant centers. However, the long-term survival rate has not increased significantly over this same period. Subclinical inflammation (SCI) is a major contributor to transplant deterioration and to increase long-term success rates of organ transplants it is vital to have a measure of SCI in the transplant tissue. SCI is currently assesse by the invasive measure of a biopsy but could be more effectively evaluated by imaging of gene(s) that are activated during inflammation. We have developed a gene expression reporter system that can be used for imaging gene expression in deep tissue. The reporters are aptamers that are expressed from a chosen promoter and are visualized when they bind their target radioligand. The aptamers behave as intracellular receptors, binding their ligands tightly and thereby providing an image of the cells in which the promoter has been activated. The current veteran team, which includes expertise in cell and molecular biology, synthetic organic chemistry and radiochemistry, will develop an aptamer reporter system for imaging local inflammation of transplanted tissues by achieving the following specific aims: 1) Prepare mammalian cells that stably express neomycin aptamers as reporters of either a regulated (Lcn2) or constitutively expressed (actin) gene, 2) Develop the chemical procedures to synthesize and radiolabel aptamer ligands, and 3) Image actin and Lcn2 gene expression in vivo. The studies proposed here have broad implications for monitoring the health of tissue transplants to enable more informed decisions regarding medications. Such monitoring is anticipated to increase the survival of transplants that have been modified by the inclusion of the aptamer SCI reporter system prior to their transplantation. The same reporter platform may be applied to other imaging needs such as stem cell trafficking or their gene expression profile to monitor their differentiation stage.