Design, synthesis, and evaluation of potent RIPK1 inhibitors with in vivo anti-inflammatory activity

RIPK1 plays a key role in the necroptosis pathway that regulates inflammatory signaling and cell death in various diseases, including inflammatory and neurodegenerative diseases. Herein, we report a series of potent RIPK1 inhibitors, represented by compound 70. Compound 70 efficiently blocks necroptosis induced by TNF alpha in both human and mouse cells (EC50 = 17-30 nM). Biophysical assay demonstrates that compound 70 potently binds to RIPK1 (K-d = 9.2 nM), but not RIPK3 (K-d > 10,000 nM). Importantly, compound 70 exhibits greatly improved metabolic stability in human and rat liver microsomes compared to compound 6 (PK68), a RIPK1 inhibitor reported in our previous work. In addition, compound 70 displays high permeability in Caco-2 cells and excellent in vitro safety profiles in hERG and CYP assays. Moreover, pre-treatment of 70 significantly ameliorates hypothermia and lethal shock in SIRS mice model. Lastly, compound 70 possesses favorable pharmacokinetic parameters with moderate clearance and good oral bioavailability in SD rat. Taken together, our work supports 70 as a potent RIPK1 inhibitor and highlights its potential as a prototypical lead for further development in necroptosisassociated inflammatory disorders. (c) 2021 Elsevier Masson SAS. All rights reserved.

Automated summary

This study reports a series of potent RIPK1 inhibitors, with compound 70 being highly active and stable in blocking necroptosis in inflammatory signaling and cell death. Compound 70 exhibits excellent properties and activity in both in vitro and in vivo experiments.