Caspase-8-mediated CYLD cleavage boosts LPS-induced endotoxic shock

Area of Science:

• Immunology
• Molecular Biology
• Cell Death Research

Background:

• Caspase-8 is crucial in inflammation and cell death.
• Its role in septic shock and cytokine production needs clarification.
• CYLD is an anti-inflammatory protein whose regulation is not fully understood.

Purpose of the Study:

• To elucidate the mechanism by which Caspase-8 influences endotoxic shock.
• To investigate the role of CYLD cleavage by Caspase-8 in regulating inflammation.
• To identify CYLD cleavage as a potential therapeutic target.

Main Methods:

• Utilized a CYLD D215A mutant mouse model resistant to Caspase-8 cleavage.
• Employed Caspase-8 and MLKL knockout mice to assess CYLD's role.
• Investigated the ubiquitination status and nuclear translocation of p65.

Main Results:

• CYLD D215A mutant mice showed protection against lethal endotoxic shock.
• CYLD deletion restored endotoxic shock sensitivity in Caspase-8/MLKL deficient mice.
• CYLD was found to remove LUBAC-mediated ubiquitination of p65, suppressing NF-κB activation.

Conclusions:

• Caspase-8 promotes endotoxic shock by cleaving and degrading CYLD, removing its anti-inflammatory function.
• The CYLD D215A mutation confers anti-inflammatory effects by resisting Caspase-8 cleavage.
• Targeting CYLD cleavage presents a promising therapeutic strategy for endotoxic shock-induced inflammation.