# Discovery and Validation of a Novel Class of Necroptosis Inhibitors Targeting RIPK1

## TL;DR

This paper introduces a new class of drugs that block necroptosis, a type of cell death linked to diseases, by targeting the RIPK1 protein.

## Contribution

The study presents a novel pharmacophore and a photoaffinity probe for RIPK1 inhibition, validated through biochemical and in vivo experiments.

## Key findings

- Compounds with a 7-phenylquinoline motif inhibit necroptosis by blocking RIPK1 autophosphorylation.
- The compounds bind to the active conformation of RIPK1 at the hinge region as type I kinase inhibitors.
- Lead compounds showed in vivo protection against acute inflammation in necroptosis models.

## Abstract

Necroptosis is a form of programmed cell death that,
when dysregulated,
is associated with cancer and inflammatory and neurodegenerative diseases.
Here, starting from hits identified from a phenotypic high-throughput
screen for inhibitors of necroptosis, we synthesized a library of
compounds containing a 7-phenylquinoline motif and validated their
anti-necroptotic activity in a novel live-cell assay. Based on these
data, we designed an optimized photoaffinity probe for target engagement
studies and through biochemical and cell-based assays established
receptor-interacting kinase 1 (RIPK1) as the cellular target, with
inhibition of necroptosis arising from the prevention of RIPK1 autophosphorylation
and activation. X-ray crystallography and mass spectrometry revealed
that these compounds bind at the hinge region of the active conformation
of RIPK1, establishing them as type I kinase inhibitors. In addition,
we demonstrated in vitro synergy with type III kinase
inhibitors, such as necrostatin-1 and found that lead compounds protected
mice against acute inflammation in necroptosis models in vivo. Overall, we present a novel pharmacophore for inhibition of human
RIPK1, a key protein involved in necroptosis, and provide a photoaffinity
probe to explore RIPK1 target engagement in cells.