The last few decades of protease research has confirmed that a number of important biological processes are strictly dependent on proteolysis. Neutrophil elastase (NE) is a critical protease in immune response and host defense mechanisms in both physiological and disease-associated conditions. Particularly, NE has been identified as a promising biomarker for early diagnosis of lung inflammation. Recent studies have shown an increasing interest in developing methods for NE activity imaging both in vitro and in vivo. Unlike anatomical imaging modalities, functional molecular imaging, including enzymatic activities, enables disease detection at a very early stage and thus constitutes a much more accurate approach. When combined with advanced imaging technologies, opportunities arise for measuring imbalanced proteolytic activities with unprecedented details. Such technologies consist in building the highest resolved and sensitive instruments as well as the most specific probes based either on peptide substrates or on covalent inhibitors. This review outlines strengths and weaknesses of these technologies and discuss their applications to investigate NE activity as biomarker of pulmonary inflammatory diseases by imaging.

中文翻译：

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中性粒细胞弹性蛋白酶活性成像：基于活性的探针和基于底物的探针的设计和应用的最新方法。

蛋白酶研究的最后几十年证实，许多重要的生物学过程严格依赖于蛋白水解。中性粒细胞弹性蛋白酶（NE）是在生理和疾病相关条件下免疫应答和宿主防御机制中的关键蛋白酶。特别是，NE已被确定为早期诊断肺部炎症的有前途的生物标志物。最近的研究表明对开发用于体外和体内NE活性成像的方法的兴趣日益增加。与解剖学成像方式不同，包括酶活性在内的功能分子成像可以在非常早期就进行疾病检测，因此构成了一种更为准确的方法。结合先进的成像技术，出现了以前所未有的细节衡量不平衡蛋白水解活性的机会。此类技术包括构建基于肽底物或共价抑制剂的最高分离度和灵敏度的仪器以及最特异性的探针。这篇综述概述了这些技术的优缺点，并讨论了它们在通过影像学调查NE活动作为肺炎性疾病的生物标志物方面的应用。