LPS-TLR4 pathway exaggerates alcoholic hepatitis via provoking NETs formation

Area of Science:

• Hepatology
• Immunology
• Microbiology

Background:

• Neutrophil infiltration is characteristic of alcoholic hepatitis (AH).
• Neutrophil extracellular traps (NETs) are a neutrophil defense mechanism.
• The gut-liver axis is implicated in AH, but NETs' role remains unclear.

Purpose of the Study:

• To investigate the presence and role of NETs in alcoholic hepatitis.
• To elucidate the mechanism by which NETs contribute to AH pathogenesis.
• To explore the link between gut microbiota, LPS, and NETs in AH.

Main Methods:

• Serum samples from AH patients were analyzed for LPS and MPO-DNA.
• Animal models (WT, NE KO, TLR4 KO mice) were used to induce AH.
• Interventions included antibiotic treatment, LPS supplementation, and NE depletion.

Main Results:

• Elevated serum MPO-DNA and LPS correlated in AH patients.
• Intrahepatic NET formation was increased in AH mice and modulated by antibiotics and LPS.
• Depletion of neutrophils (NE) or TLR4 deficiency ameliorated AH markers.
• Gut sterilization and LPS re-supplementation affected NETs and AH markers in a TLR4-dependent manner.

Conclusions:

• Intestinal-derived LPS promotes NET formation in AH via the TLR4 pathway.
• NETs accelerate alcoholic hepatitis progression, contributing to liver injury, inflammation, and fibrosis.
• Targeting the LPS-NETs-TLR4 axis may offer therapeutic strategies for AH.