Pulmonary Transgene Expression Imaging with PET

描述（由申请人提供）： 虽然已经清楚，正电子发射断层扫描（PET）成像可用于跟踪整个动物的转基因表达，但迄今为止还没有研究证明使用分子成像方法（如PET）跟踪疾病实验模型中的转基因表达的实用性。我们建议通过给大鼠施用携带生物学相关基因（先前合作者显示影响急性呼吸窘迫综合征、ARDS和肺动脉高压的不同疾病模型的病理生理学）和“PET报告基因”（例如病毒胸苷激酶，tk）的腺病毒载体来解决这一重要问题，两者都在相同启动子的控制下。将进行成像，以跟踪与疾病修饰基因的生理效应（也用非侵入性成像研究）相关的报告基因转基因表达的位置（在肺内）、时间（开始和持续时间）和幅度。因此，我们的建议有以下具体目标：具体目标1：使用PET成像，确定实验性肺损伤过程中β 2肾上腺素能受体（β 2AR）转基因表达的时间、幅度、持续时间和功能效应。 1.a用PET和体外测定法测量作为病毒剂量函数的β 2 AR和tk表达的变化。 1.b在正常动物中用PET确定基因表达的时间过程。 1.c在急性高氧肺损伤（ARDS的肺损伤模型）中将PET报告基因表达、β-2肾上腺素能受体转基因表达和β 2AR转基因的功能效应（也用PET成像评估）（时间和地理上，即在肺内）相关联。具体目标二：使用PET成像和超声心动图，确定实验性肺动脉高压期间前列腺素I2合酶转基因表达的时间、幅度、持续时间和功能效应。将在肺动脉高压的野百合碱模型（亚急性肺血管疾病模型）的两种变体中实施一系列类似的研究（具体目标2.a、2.b和2.c）。 研究结果将展示PET成像如何用于研究基因表达变化对疾病自然史的影响，或开发改变疾病结局的治疗方案。

DESCRIPTION (provided by applicant): Although it is already clear that positron emission tomographic (PET) imaging can be used to follow transgene expression in whole animals, no studies to date have yet demonstrated the utility of using molecular imaging methods, such as PET, to follow transgene expression in experimental models of disease. We propose to address this important issue by administering, to rats, adenoviral vectors carrying biologically relevant genes (shown previously by collaborators to affect the pathophysiology of different disease models of the acute respiratory distress syndrome, ARDS, and of pulmonary hypertension) and a "PET reporter gene" (e.g. viral thymidine kinase, tk), both under the control of the same promoter. Imaging will be performed to follow the location (within the lungs), timing (onset and duration), and magnitude of reporter transgene expression in relation to the physiologic effects (also studied with non-invasive imaging) of the disease modifying genes. Thus, our proposal has the following specific aims: Specific Aim 1: using PET imaging, determine the timing, magnitude, duration, and functional effects of beta-2 adrenergic receptor (beta2AR) transgene expression during experimental lung injury. 1.a Measure changes with PET and in vitro assays of beta2AR and tk expression as a function of viral dose. 1.b Determine the time course of gene expression with PET in normal animals. 1.c Correlate (temporally and geographically, i.e. within the lungs) PET reporter gene expression, beta-2 adrenergic receptor transgene expression, and functional effects of the beta2AR transgene (also evaluated with PET imaging) in acute hyperoxic lung injury (a lung injury model of ARDS). Specific Aim 2: using PET imaging and echocardiography, determine the timing, magnitude, duration, and functional effects of prostaglandin I2 synthase transgene expression during experimental pulmonary hypertension. An analogous series of studies (Specific Aims 2.a, 2.b and 2.c) will be implemented in two variants of the monocrotaline model of pulmonary hypertension, a model of sub-acute pulmonary vascular disease. The results will demonstrate how PET imaging can be used to study the impact of changes in gene expression on the natural history of disease or to develop therapeutic protocols to alter disease outcome.