Samotolisib Attenuates Acute Liver Injury Through Inhibiting Caspase-11-Mediated Pyroptosis Via Regulating E3 Ubiquitin Ligase Nedd4

Abstract

Acute liver injury (ALI) is associated with poor survival in patients with sepsis. During sepsis, the liver is the main site of bacterial endotoxin-induced inflammation. Lipopolysaccharide (LPS) promotes caspase-4/5/11 activation, leading to pyroptosis, a major sepsis driver. This study aimed to identify novel drugs that can control hepatocyte caspase-4/5/11 activation during sepsis. We performed LPS-induced caspase-11 activation and pyroptosis in RAW 264.7 cells and established an LPS-induced ALI mouse model. We identified samotolisib (ST), a novel dual phosphoinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) inhibitor, by screening a library of 441 pyroptosis compounds with known targets, which dose-dependently inhibited caspase-11 activation and N-terminal fragment of gasdermin D (GSDMD-NT) generation, reducing RAW 264.7 cell pyroptosis. In mice, ST preconditioning improved survival, attenuated LPS-induced serum alanine aminotransferase and aspartate aminotransferase activity, and inhibited severe liver inflammation and damage. Importantly, ST treatment activated Nedd4, which directly interacts with and mediates caspase-11 ubiquitination and degradation. This was largely abrogated by insulin-like growth factor 1. ST ameliorated LPS-induced hepatotoxicity by inhibiting caspase-11/GSDMD-NT pyroptosis signaling via regulating PI3K/AKT/mTOR/Nedd4 signaling. Hence, ST may play a key role in the prevention of liver injury in patients with sepsis.