Julie Charton

A novel series of potent agonists of the bile acid receptor TGR5 bearing a dihydropyridone scaffold was developed from a high-throughput screen. Starting from a micromolar hit compound, we implemented an extensive structure-activity-relationship (SAR) study with the synthesis and biological evaluation of 83 analogues. The project culminated with the identification of the potent nanomolar TGR5 agonist 77A. We report the GLP-1 secretagogue effect of our lead compound ex vivo in mouse colonoids and in vivo. In addition, to identify specific features favorable for TGR5 activation, we generated and optimized a three-dimensional quantitative SAR model that contributed to our understanding of our activity profile and could guide further development of this dihydropyridone series.

The main protease (3CLp) of the SARS‐CoV‐2, the causative agent for the COVID‐19 pandemic, is one of the main targets for drug development. To be active, 3CLp relies on a complex interplay between dimerization, active site flexibility, and allosteric regulation. The deciphering of these mechanisms is a crucial step to enable the search for inhibitors. In this context, using NMR spectroscopy, we studied the conformation of dimeric 3CLp from the SARS‐CoV‐2 and monitored ligand binding, based on NMR signal assignments. We performed a fragment‐based screening that led to the identification of 38 fragment hits. Their binding sites showed three hotspots on 3CLp, two in the substrate binding pocket and one at the dimer interface. F01 is a non‐covalent inhibitor of the 3CLp and has antiviral activity in SARS‐CoV‐2 infected cells. This study sheds light on the complex structure‐function relationships of 3CLp and constitutes a strong basis to assist in developing potent 3CLp inhibitors.

Chemical biology and drug discovery are two scientific activities that pursue different goals but complement each other. The former is an interventional science that aims at understanding living systems through the modulation of its molecular components with compounds designed for this purpose. The latter is the art of designing drug candidates, i.e., molecules that act on selected molecular components of human beings and display, as a candidate treatment, the best reachable risk benefit ratio. In chemical biology, the compound is the means to understand biology, whereas in drug discovery, the compound is the goal. The toolbox they share includes biological and chemical analytic technologies, cell and whole-body imaging, and exploring the chemical space through state-of-the-art design and synthesis tools. In this article, we examine several tools shared by drug discovery and chemical biology through selected examples taken from research projects conducted in our institute in the last decade. These examples illustrate the design of chemical probes and tools to identify and validate new targets, to quantify target engagement in vitro and in vivo, to discover hits and to optimize pharmacokinetic properties with the control of compound concentration both spatially and temporally in the various biophases of a biological system.

The main protease (3CLp) of the SARS‐CoV‐2, the causative agent for the COVID‐19 pandemic, is one of the main targets for drug development. To be active, 3CLp relies on a complex interplay between dimerization, active site flexibility, and allosteric regulation. The deciphering of these mechanisms is a crucial step to enable the search for inhibitors. In this context, using NMR spectroscopy, we studied the conformation of dimeric 3CLp from the SARS‐CoV‐2 and monitored ligand binding, based on NMR signal assignments. We performed a fragment‐based screening that led to the identification of 38 fragment hits. Their binding sites showed three hotspots on 3CLp, two in the substrate binding pocket and one at the dimer interface. F01 is a non‐covalent inhibitor of the 3CLp and has antiviral activity in SARS‐CoV‐2 infected cells. This study sheds light on the complex structure‐function relationships of 3CLp and constitutes a strong basis to assist in developing potent 3CLp inhibitors.

PEGylation of therapeutic agents is known to improve the pharmacokinetic behavior of macromolecular drugs and nanoparticles. In this work, we performed the conjugation of polyethylene glycols (220–5000 Da) to a series of non-steroidal small agonists of the bile acids receptor TGR5. A suitable anchoring position on the agonist was identified to retain full agonistic potency with the conjugates. We describe herein an extensive structure–properties relationships study allowing us to finely describe the non-linear effects of the PEG length on the physicochemical as well as the in vitro and in vivo pharmacokinetic properties of these compounds. When appending a PEG of suitable length to the TGR5 pharmacophore, we were able to identify either systemic or gut lumen-restricted TGR5 agonists.