Synthesis of optical probes for the visualization of human neutrophil elastase
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Date
28/11/2019Item status
Restricted AccessEmbargo end date
28/11/2020Author
Evans, Vikki
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Abstract
Optical medical imaging is a new technology that uses light to improve clinical
processes such as disease diagnosis and tumour margin delineation. It has the
potential to produce high-resolution images in real-time, with continuously
generated images on or in biological tissues at a molecular level. Imaging
inside the lung can be accomplished via the use of microendoscopy, and this
has been used to detect and analyse several pulmonary diseases, which
traditionally have been hard to unequivocally define.
Several pulmonary diseases have been linked with overactive leukocytes
within the lung. A class of leukocytes, neutrophils, are used by the body to
aggressively destroy potential pathogens with an arsenal of proteases
including human neutrophil elastase (HNE) at its disposal. However,
overexpression of unregulated HNE has been implicated in a number of
pulmonary diseases, such as fibrosis, COPD and acute lung injury with
irreversible damage caused to lung tissue through protein degradation.
Currently in the clinic, it is difficult to identify and quantify unregulated HNE
in vivo using traditional methods of diagnosis. Thus, the ability to quantify and
evaluate numbers of neutrophils and levels of HNE using an in vivo technique
would be very valuable.
Within this work, a library of optical probes to selectively detect HNE at a
molecular level were designed and evaluated. The probes consist of two parts:
an inhibitor warhead designed to irreversibly bind to HNE, and a fluorophore.
Two different classes of warheads have been synthesised and conjugated to a
variety of fluorophores that emit over a range of wavelengths. Having optical
probes over the span of several wavelength ranges is beneficial as it allows
multiplex imaging so several diseases can be screened simultaneously, as well
as removing the probes from possible tissue autofluorescence wavelengths.
The probes were evaluated for their binding efficacy with HNE, toxicity
against erythrocytes and then, subsequently used to detect and image the
presence and localisation of HNE within neutrophils. It is envisioned that the
use of optical probes to detect HNE overexpression will lead to quicker
diagnoses for patients with debilitating pulmonary diseases.