Endotoxin-Stimulated Hepatic Stellate Cells Augment Acetaminophen-Induced Hepatocyte Injury

Area of Science:

• Hepatology
• Immunology
• Toxicology

Background:

• Acetaminophen (APAP)-induced liver injury is a significant clinical concern.
• The role of inflammatory bacterial endotoxin, lipopolysaccharide (LPS), and hepatic stellate cells (HSCs) in APAP hepatotoxicity is not fully understood.

Purpose of the Study:

• To investigate the role of LPS-stimulated HSCs in APAP-induced liver injury.
• To elucidate the underlying molecular mechanisms involving cytokine production and signaling pathways.

Main Methods:

• Rats and mice were treated with APAP, LPS, or vehicle, with or without HSC depletion.
• In vitro studies utilized hepatocytes and HSC-conditioned medium.
• Assays included histopathology, TUNL staining, caspase-3 activation, Western blotting for IRF1, cytokine analysis, and antibody neutralization.

Main Results:

• Combined LPS and APAP administration significantly augmented liver injury compared to either agent alone.
• LPS-stimulated HSCs produced interferon-beta (IFN-β), which mediated APAP/LPS-induced hepatocyte apoptosis via IRF1 signaling.
• HSC depletion protected mice from APAP and LPS/APAP-induced liver injury, reducing oxidative stress and pro-inflammatory cytokine production.

Conclusions:

• Hepatic stellate cells play a critical role in exacerbating APAP-induced liver injury, with or without LPS preconditioning.
• The IFN-β-IRF1 signaling pathway is a key mechanism by which HSCs contribute to hepatotoxicity.
• Targeting HSCs or their signaling pathways may offer therapeutic strategies for managing APAP overdose.