Obeticholic acid improved triptolide/lipopolysaccharide‐induced hepatotoxicity by inhibiting caspase‐11‐GSDMD pyroptosis pathway

Abstract

This study was designed to investigate the potential role of farnesoid X receptor (FXR) in abnormal bile acid metabolism and pyroptosis during the pathogenesis of triptolide (TP)/lipopolysaccharide (LPS)-induced hepatotoxicity. Moreover, the protective effect of obeticholic acid (OCA) was explored under this condition. In vivo, female C57BL/6 mice were administrated with OCA (40 mg/kg bw, intragastrical injection) before (500 μg/kg bw, intragastrical injection)/LPS (0.1 mg/kg bw, intraperitoneal injection) administration. In vitro, AML12 cells were treated with TP (50 nM) and TNF-α (50 ng/ml) to induce hepatotoxicity; GW4064 (5 μM) and cholestyramine (CHO) (0.1 mg/ml and 0.05 mg/ml) were introduced to explain the role of FXR/total bile acid (TBA) in it. Serum TBA level was significantly elevated, which was induced by FXR suppression. And both GW4064 and CHO intervention presented remarkable protective effects against TP/TNF-α-induced NLRP3 upregulation and pyroptosis pathway activation. Pre-administration of FXR agonist OCA successfully attenuated TP/LPS-induced severe liver injury by reducing serum bile acids accumulation and inhibiting the activation of caspase-11-GSDMD (gasdermin D) pyroptosis pathway.We have drawn conclusions that TP aggravated liver hypersensitivity to LPS and inhibited FXR-SHP (small heterodimer partner) axis, which was served as endogenous signals to activate caspase-11-GSDMD-mediated pyroptosis contributing to liver injury. OCA alleviated TP/LPS-induced liver injury accompanied by inhibiting caspase-11-GSDMD-mediated pyroptosis pathway and decreased serum TBA level.The results indicated that FXR might be an attractive therapeutic target for TP/LPSinduced hepatotoxicity, providing an effective strategy for drug-induced liver injury.

CHIR-98014, a GSK 3β Inhibitor, Protects Against Triptolide/Lipopolysaccharide-Induced Hepatotoxicity by Mitochondria-Dependent Apoptosis Inhibition

“…TNF-R1, which is expressed on almost every mammalian cell type, including hepatocytes, regulates a number of biological responses, ranging from NF-κB activation to cell death, when it is activated by TNF-α. Previously, we confirmed that decreased TNF-α levels exogenously administered or facilitated by LPS might counteract TP-induced hepatotoxic reactions, especially apoptosis and necroptosis, in vivo and in vitro . To maintain the consistency of the experimental conditions, TNF-α was used instead of LPS as a stimulus for in vitro experiments.…”

“…Thus, we selected LPS as a stimulant and found that TP/LPS cotreatment caused severe liver injury and massive hepatic cell death. 44,45 As Tolllike receptor 4 (TLR-4) is expressed at low levels in hepatocytes, it is not suitable to use LPS as a direct stimulant for in vitro hepatocyte experiments. However, TNF-α is a pro-inflammatory factor produced by LPS-activated immune cells.…”

“…Based on long-term studies of the toxicological mechanism of TP, our research group proposed that TP treatment might disrupt immune homeostasis, leading to liver hypersensitivity upon pathogen stimulation. Thus, we selected LPS as a stimulant and found that TP/LPS cotreatment caused severe liver injury and massive hepatic cell death. , As Toll-like receptor 4 (TLR-4) is expressed at low levels in hepatocytes, it is not suitable to use LPS as a direct stimulant for in vitro hepatocyte experiments. However, TNF-α is a pro-inflammatory factor produced by LPS-activated immune cells.…”

“…Previously, we confirmed that decreased TNF-α levels exogenously administered or facilitated by LPS might counteract TP-induced hepatotoxic reactions, especially apoptosis and necroptosis, in vivo and in vitro. 44 To maintain the consistency of the experimental conditions, TNF-α was used instead of LPS as a stimulus for in vitro experiments.…”