Lab rotation project description
Building on our previous research on the development of Fluorescence Resonance Energy Transfer (FRET) and Magnetic Resonance Imaging (MRI) probes, we propose to synthesize an MRI active probe that can measure the activity of a chosen protease enzyme in vivo. To achieve this a peptide specific to the target enzyme will be modified with a polyfluorinated NMR-active reporter group and a Gd(III)-DOTA chelate.
Whilst the probe is intact the Gd(III), because of its strong paramagenetic properties and close proximity, will significantly broaden and reduce the 19F NMR signal. Once the protease has cleaved the peptide linking the two MRI active groups together, the 19F NMR signal will sharpen and allow the level of enzyme present to be quantified. The project will involve synthetic chemistry and associated analytical methods (NMR, IR, MS, HPLC). If time allows, the kinetic parameters for the cleavage of the MRI probe with the isolated enzyme will be determined in vitro.
There is a need for new tools. Matrix metalloproteases (MMPs) are a family of enzymes that derive their name from their role in tissue remodelling. The activity of MMPs in vivo is normally tightly regulated, but when unchecked, MMPs have been shown to be a driving factor in a range of diseases, including cancer progression or disorders of the immune system. A number of MMP inhibitors have been progressed to stage three clinical trials, though largely without success. This was partly because the inhibitors were broad range, affecting a number of MMPs simultaneously, lacking specificity, and partly due to uncertainty of the local drug doses that were achieved. The relationship between MMPs, their inhibitors and targets is complex. There is a lack of imaging biomarkers that allow to monitor local MMP activity in vivo, and the targeted, activity dependant delivery of drugs that can control MMP concentration locally and specifically. Molecular MRI can also provide information about the molecular origin of the signal and metabolic activity.
The aims of this project are to develop and apply a new theranostic material combining the ability to measure and control in situ regulation of enzymatic activity, allowing controlled release of MMP inhibitors and simultaneous monitoring in vivo with molecular MRI. The hypothesis is that the combination of imaging biomarker and controlled delivery of enzyme inhibitors will allow to quantify as well as regulate local enzyme concentration.
This project builds on our previously developed hydrogel that is responsive to MMPs and can release enzyme inhibitors and our MRI nanosensor that can relay local MMP concentration through changes in the MRI signal. We will initially assess the specificity and sensitivity in vitro, with fluorescence microscopy and MRI. We will then modify the system if necessary, and demonstrate the capabilities in tissue samples with locally induced changes in MMPs.
In alignment with the Biotechnology and Biological Sciences Research Council (BBSRC) remit, we currently hold a BBSRC iCASE PhD studentship with our industrial partner GE (BB/R506394/1, PI HM Faas) and recently completed a BBSRC Project grant ‘Monitoring enzyme activity with a hyperpolarized MRI biosensor’ (BB/N021460/1, PI HM Faas), which this PhD project is aligned with. The proposal sits within the BBSRC priorities, “Technology development for the biosciences” (bioimaging), and will directly contribute, through the translational imaging component, to the priority ‘Healthy ageing across the lifecourse’.
The overall project is highly interdisciplinary and key collaborators in the School of Medicine are Thomas Meersmann, Galina Pavlovskaya, Simon Johnson and Beth Coyle.