# The Endogenous Metabolite TDCA Ameliorates LPS-Driven Liver Injury via Modulation of Caspase-11/GSDMD-Mediated Pyroptosis

## TL;DR

The study shows that the bile acid TDCA protects the liver from LPS-induced injury by reducing a type of cell death called pyroptosis.

## Contribution

The novel finding is that TDCA, an endogenous metabolite, ameliorates LPS-driven liver injury via the Caspase-11/GSDMD pyroptotic pathway.

## Key findings

- TDCA reduces pyroptosis in macrophages by suppressing caspase-11 and GSDMD activation.
- TDCA treatment improves survival and reduces liver damage in a sepsis-induced liver injury model.
- TDCA attenuates systemic inflammation and histopathological damage in LPS-challenged mice.

## Abstract

The liver is a central immunometabolic organ during endotoxemia and a major target of sepsis-related injury. Intriguingly, the liver exhibits a notable resilience to endotoxemia or septic insults, suggesting the activation of endogenous protective mechanisms. The bile acid taurodeoxycholic acid (TDCA) demonstrates hepatoprotective properties; nonetheless, its role and mechanism in lipopolysaccharide (LPS)-driven inflammatory liver injury remain elusive. This study reveals that LPS challenge induces significant reprogramming of hepatic bile acid metabolism, with TDCA being markedly elevated in LPS-challenged mice. In vitro, TDCA dose-dependently attenuated pyroptosis in bone marrow-derived macrophages, as evidenced by reduced lactate dehydrogenase (LDH) release, decreased interleukin-1 beta (IL-1β) and interleukin-18 (IL-18) secretion, and suppressed dye Oxazole yellow uptake. Consistent with reduced non-canonical inflammasome signaling, TDCA treatment was associated with decreased activation of caspase-11 and its downstream targets Gasdermin D (GSDMD) and IL-1β. In a lethal D-Galactosamine (D-GalN)/LPS-induced toxin-sensitized inflammatory liver injury model, therapeutic administration of TDCA (3, 6 mg/kg) profoundly improved survival rates (40% and 80%, respectively), attenuated liver injury, reduced alanine aminotransferase (ALT) and aspartate aminotransferase (AST), suppressed systemic inflammation (IL-1β and IL-18), and ameliorated histopathological damage. Crucially, TDCA treatment reduced the activation of the caspase-11/GSDMD pathway in the septic liver. Our findings demonstrate that TDCA is an endogenously mobilized bile acid that confers protection against LPS-driven inflammatory liver injury, with effects supporting a role for modulation of the Caspase-11/GSDMD pyroptotic pathway. These observations provide hypothesis-generating implications for sepsis-associated liver injury that warrant further validation in clinically relevant sepsis models and pathway-necessity studies.