James Eaton

Inflammation plays a key pathophysiological role in atherosclerosis, myocardial infarction and stroke, and the recent CANTOS trial has shown that targeting inflammation is an effective therapeutic approachto treating these diseases. Chemokines are a group of ~50 small secreted proteins that bind ~20 G-protein coupled receptors to recruit immune-inflammatory cells to damaged tissue and are validated therapeutic targets for these cardiovascular inflammatory diseases. Major obstacles to developing therapeutics targeting the chemokine system in inflammatory disease are the expression of multiple chemokines at sites of inflammation, the “one-to-many” interactions between chemokines and target receptors, and the expression of multiple receptors on the surface of inflammatory cells. Moreover, the large and flat protein-protein interaction (PPI) interface between the chemokine ligand and receptor has made it challenging for the generation of chemically tractable chemokine inhibitors that target the ligand-receptor interaction. Evasins are small (10-15 kDa) chemokine binding proteins found in tick saliva that have a unique mechanism of action. Unlike monovalent therapeutics they bind multiple chemokines in a “one-to-many” fashion, disrupting multiple chemokine/receptor interactions, efficiently neutralizing chemokine function. As a result they have potent anti-inflammatory effects in preclinical models including myocardial infarction and plaque inflammation. Using a platform yeast surface display technology (“Bug-to-Drug”), we have identified 28 novel evasins that bind and neutralize multiple chemokines that are key players in monocyte, neutrophil and T-cell recruitment. However, key limitations of biologicals are the high costs of manufacture, the possibility of immunogenicity and the requirement for parenteral delivery, which limit their application to chronic diseases such as atherosclerosis. These limitations have been overcome in several instances by the development of peptidomimetic therapeutics, which are derived from biologicals and mimic their activity. Cardiovascular examples include ACE inhibitors and tirofiban, which target PPIs, and were developed through the deconvolution of a protein-protein interaction to a protein-peptide interaction and then finally to a peptidomimetic (small molecule)-protein interaction. It is therefore highly desirable to have a chemically synthesizable peptide or small molecule that can mimic the effect of evasins. To this end I have been utilising various approaches, including mass spectrometry and homology modelling, to engineer chemically tractable molecules that can mimic evasin function.