Ageo Miccoli’s research while affiliated with Cardiff University and other places

The specific targeting of protein‐protein interactions by phosphoserine‐containing small molecules has been scarce due to the dephosphorylation of phosphoserine and its charged nature at physiological pH, which hinder its uptake into cells. To address these issues, we herein report the synthesis of phosphoserine aryloxy triester phosphoramidates as phosphoserine prodrugs that are enzymatically metabolized to release phosphoserine. This phosphoserine‐masking approach was applied to a phosphoserine‐containing inhibitor of 14‐3‐3 dimerization, and the generated prodrugs exhibited improved pharmacological activity. Collectively, this provided a proof of concept that the masking of phosphoserine with biocleavable aryloxy triester phosphoramidate masking groups is a viable intracellular delivery system for phosphoserine‐containing molecules. Ultimately, this will facilitate the discovery of phosphoserine‐containing small‐molecule therapeutics.

Many cellular protein-protein interactions (PPIs) are mediated by phosphoserine. The specific targeting of these PPIs by phosphoserine-containing small molecules has been scarce due to the dephosphorylation of phosphoserine and its charged nature at physiological pH, which hinders its uptake into cells. To address these issues, we herein report the masking of the phosphate group of phosphoserine with biocleavable aryloxy triester phosphoramidate groups. A combination of in vitro enzymatic assays and in silico studies, using carboxypeptidase Y and Hint-1 respectively, showed that the phosphate masking groups are metabolized to release phosphoserine. To probe the applicability of this phosphoserine masking approach, it was applied to a phosphoserine-containing inhibitor of 14-3-3 dimerization, and this generated molecules with improved pharmacological activity in cells compared to their unmasked phosphoserine-containing parent compound. Collectively, the data showcases the masking of phosphoserine with biocleavable aryloxy triester phosphoramidate masking groups as an efficient intracellular delivery system for phosphoserine-containing molecules.

Unmasked phohate groups of phosphotyrosine-containing molecules carry two negative charges at physiological pH, which compromise their (passive) celular uptake. Also, these phosphate groups are often cleaved off by phosphatases. Together, these ultimately limit the pharmacological efficacy of the phosphotyrosine-containing compounds. To address these drawbacks, we herein present the application of the aryloxy triester phosphoramidate prodrug technology, a monophosphate prodrug technology, to the phosphotyrosine-containing compound ISS-610-Met, an analogue of the anticancer STAT3 dimerization inhibitor ISS-610. Our data shows that the generated ISS-610-Met prodrugs exhibited enhanced pharmacological activity and inhibition of STAT3 downstream signaling compared to the parent compound ISS-610-Met and the known STAT3 dimerization inhibitor ISS-610. These encouraging results provide a compelling proof of concept for the potential of the aryloxy triester phosphoramidate prodrug technology in the discovery of novel therapeutics that contain phosphotyrosine and its phospho mimics.

Mutations in PINK1, which impair its catalytic kinase activity, are causal for autosomal recessive early onset Parkinson's disease (PD). Various studies have indicated that the activation of PINK1 could be a useful strategy in treating neurodegenerative diseases such as PD. Herein, we show that the anthelmintic drug niclosamide and its analogues are capable of activating PINK1 in cells via reversible impairment of the mitochondrial membrane potential. Using these compounds, we demonstrate for the first time that the PINK1 pathway is active and detectable in primary neurons. Our findings suggest that niclosamide and its analogues are robust compounds to study the PINK1 pathway and may hold promise as a therapeutic strategy in Parkinson's and related disorders.

Since loss of function mutations of PINK1 lead to early-onset Parkinson's disease, there has been growing interest in the discovery of small molecules that amplify the kinase activity of PINK1. We herein report the design, synthesis, serum stability and hydrolysis of four kinetin riboside ProTides. These ProTides, along with kinetin riboside, activated PINK1 in cells independent of mitochondrial depolarization. This highlights the potential of modified nucleosides and their phosphate prodrugs as treatments for neurodegenerative diseases.