Stabilin receptors clear LPS and control systemic inflammation.

Area of Science:

• Immunology
• Cell Biology
• Hepatology

Background:

• Lipopolysaccharides (LPS) trigger lethal endotoxemia if not cleared from circulation.
• Liver sinusoidal endothelial cells (LSEC) are key in systemic LPS clearance via unknown mechanisms.

Purpose of the Study:

• To elucidate the mechanisms of LPS clearance by LSEC.
• To investigate the roles of Stabilin-1 and Stabilin-2 (Stab1, Stab2) in LPS uptake and endotoxemia.
• To determine the relationship between LPS clearance and inflammatory responses.

Main Methods:

• Utilized Stabilin double knockout (Stab DK), Stab1 KO, and Stab2 KO mouse models.
• Administered LPS to mice and assessed systemic cytokine production, survival rates, and LPS clearance.
• Quantified LPS uptake and endocytosis by LSEC.

Main Results:

• LPS clearance by LSEC involves endocytosis via Stab1 and Stab2, independent of TLR4.
• Stab1 deficiency (Stab1 KO and Stab DK) led to increased cytokine production and mortality upon LPS exposure.
• Stab1, not Stab2, primarily mediates LPS clearance and limits TLR4-driven inflammation.

Conclusions:

• Stab1 is a crucial receptor for proactive LPS clearance, mitigating TLR4-mediated inflammation.
• Stab1 and TLR4 act as opposing receptors for LPS.
• Optimizing Stab1-mediated LPS clearance offers a therapeutic strategy for endotoxemia.