Molecular Imaging of Protein Glycosylation in Living Subjects

描述(由申请人提供)：该项目的主要目标是开发仪器和化学成像技术，以促进活体受试者蛋白质糖基化的研究。蛋白质糖基化是翻译后修饰(PTM)中最丰富、最复杂的一种。蛋白质糖基化的变化与癌症进展、神经紊乱和许多其他疾病相关。此外，葡聚糖在时间、空间和环境上都是动态的。因此，为了真正研究多糖在健康和疾病中的功能，应该在活体受试者中对它们的动态时空行为进行成像，并在适当的情况下，在它们修饰的蛋白质的背景下进行成像。然而，目前的体内成像工具具有有限的空间和时间分辨率，并且不能可视化蛋白质糖基化。我们提出了一种新的分子成像方式，可以在活体小鼠癌症模型中成像多糖的时空行为。这些工具将推动糖生物学领域的发展，加快新疾病生物标记物的发现和验证，并将传统生物化学与高水平的生物疾病模型联系起来。除了基本的癌症生物学前景外，成像肿瘤糖蛋白可能会提供肿瘤侵袭性的指示。这些信息将指导前列腺癌等疾病的治疗决定(建议患者进行前列腺切除术，而不是“积极监测”)以及其他癌症类型。我们将优化我们开发的一种基于光学相干断层扫描的新成像仪器，使基于纳米颗粒的造影剂能够以超高灵敏度在活组织中可视化(目标1)。第二，我们将合成两类新的纳米粒子显像剂：第一类用于靶向和可视化特定的糖链表位(目标2a)，第二类用于靶向和可视化特定的感兴趣蛋白质上的特定的糖链表位(目标2b)。第一类显像剂将用于可视化唾液酸的水平，唾液酸是一种与癌症进展和转移相关的重要多糖。第二类将用于监测αvβ3整合素上的唾液酸水平。αvβ3整合素的唾液酸化可能在促进血管生成和转移中发挥重要作用，但目前对此知之甚少。我们将在原位前列腺癌小鼠模型中验证新的成像仪器和显像剂，并研究前列腺癌进展和转移过程中唾液酸和唾液酸化的αvβ3整合素的时空模式(目标3)。

DESCRIPTION (provided by applicant): The broad objective of this project is to develop instrumentation and chemistry imaging technologies to advance the study of protein glycosylation in living subjects. Protein glycosylation is the most abundant and complex posttranslational modification (PTM). Changes in protein glycosylation have been correlated with cancer progression, neurological disorders and many other diseases. Moreover, glycans are dynamic in time, space and environment. Hence, in order to truly study the function of glycans in health and disease, their dynamic spatiotemporal behavior should be imaged in living subjects, and where relevant, in the context of the proteins they modify. However, current in vivo imaging tools have limited spatial and temporal resolutions and are not capable of visualizing protein glycosylations. We propose a novel molecular imaging modality that would allow imaging the spatiotemporal behavior of glycans in living murine cancer models. Such tools would advance the field of glycobiology, accelerate the discovery and validation of new disease biomarkers, and bridge traditional biochemistry with high-level biological disease models. Beyond the basic cancer biology prospects, imaging the tumor glycome may provide an indication on the tumor aggressiveness. Such information will guide treatment decisions of diseases such as prostate cancer (advise patients on prostatectomy versus "active surveillance") as well as other cancer types. We will optimize a new imaging instrument we developed based on optical coherence tomography, to allow visualizing nanoparticle-based contrast agents in living tissues with ultrahigh sensitivities (Aim 1). Second, we will synthesize two new classes of nanoparticle imaging agents: the first for targeting and visualizing a specific glycan epitope (Aim 2a) and the second for targeting and visualizing a specific glycan epitope on a specific protein of interest (Aim 2b). The first class of imaging agents will be used to visualize levels of sialic acid, an important glycan associated with cancer progression and metastasis. The second class will be used to monitor sialic acid levels on αvβ3 integrin. The sialylation of αvβ3 integrin may play a vital role in promoting angiogenesis and metastasis, but is currently poorly understood. We will validate the new imaging instrumentation and imaging agents in orthotopic prostate cancer mouse models and study the spatiotemporal patterns of sialic acid and sialylated αvβ3 integrin during prostate cancer progression and metastasis (Aim 3).