Oral Presentation International Peptide Symposium 2023

A wide range of dietary phytochemicals have been demonstrated to reduce inflammation through modulating the activity of inflammatory transcription factors, such as NFκB, STAT1 and STAT3. Many of these compounds feature electrophilic functionalities, enabling covalent bonding with the sulfhydryl side chain of cysteine residues within proteins. The notable anti-inflammatory potential of these dietary electrophiles has been associated with a reduced risk of acute ischaemic stroke and venous thromboembolism. However, the impact of such covalent modifications on the function and activity of platelets – vital cellular components of blood orchestrating hemostasis and thrombosis – remains largely unexplored. To address this question, we examined platelet phenotypes associated with the irreversible engagement of proteins by 23 dietary electrophiles with known immunomodulatory activities. This led to the identification of unique antiplatelet selectivity profiles for naturally-occurring isothiocyanates and polyphenols, where the platelets’ response to ADP agonist was attenuated without impairing thrombin-mediated activation. By integrating a Click chemistry-based target enrichment strategy with a multiplexed Tandem Mass Tag (TMT) proteomic mapping approach, we uncovered a novel mode of action beyond gene regulation. This antiplatelet mechanism hinges on the electrophilic modulation of protein chaperone activities in platelets, which in turn influences the PI3K/Akt signalling pathway, resulting in the distinctive antiplatelet phenotypes.