Highly Selective and Rapidly Activatable Fluorogenic Thrombin Sensors and Application in Human Lung Tissue

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.A. Megia-Fernandez, B. Mills, C. Michels, S.V. Chankeshwara, K. Dhaliwal and M. Bradley
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Heriot-Watt University/University of Edinburgh

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The title of this paper means finding a synthetic compound than can be “turned on” as a fluorescent signal when the enzyme Thrombin is present in tissue. The synthetic compound is not affected by the presence of other enzymes. This is useful because high levels of Thrombin are related to certain diseases that can appear in the human lung, and therefore these compounds could allow for better diagnosis.

Introduction:

Thrombin is an important enzyme in the human body, involved in blood coagulation and many other processes. Increased levels of Thrombin activity have been found in models of acute lung injury and in patients with pulmonary fibrosis, which is a disease that builds up scar tissue in your lungs and makes them stiff.

Aim:

The aim of this work was to find a Thrombin fluorogenic probe – a compound which changes how it emits light in the presence of that particular enzyme.

Method:

After preparing and studying a library of peptides (small proteins that can react with Thrombin), a lead candidate was chosen from which to create a fluorogenic probe with improved solubility and selectivity– good selectivity is important to avoid “false positive” results when detecting the enzyme. The fluorescent probe can be applied to ex vivo human lung tissue to identify the formation of excess fibrous connective tissue.

Results:

To find the best probe, different compounds have been prepared in the lab and undergone biological assessment for optimal performance. The candidate probe enables the reliable and accurate detection of Thrombin in human lung tissue samples where other highly similar enzymes are present, such as Plasmin and Factor Xa. The development of a fast and selective probe for Thrombin detection has important implications in the improved diagnosis and therapeutic stratification of early stages of diseases. If our fluorescent probe detects high levels of Thrombin, it can be related with a diagnosis of fibrotic tissue.

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The advanced article was published in Organic & Biomolecular Chemistry