Caspase-11 counteracts mitochondrial ROS-mediated clearance of Staphylococcus aureus in macrophages

Area of Science:

• Microbiology
• Immunology
• Cell Biology

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant public health threat due to antibiotic resistance.
• MRSA is an intracellular pathogen that can survive within macrophages, professional phagocytes.

Purpose of the Study:

• To investigate the role of CASP11 in MRSA survival within murine macrophages.
• To elucidate the mechanisms by which MRSA evades intracellular killing.

Main Methods:

• Utilized murine macrophages and MRSA infection models.
• Assessed the association of MRSA-containing vacuoles with mitochondria.
• Investigated the effect of antimycin A (Ant A) and cytochalasin D on MRSA survival.
• Measured caspase cleavage and cytokine production.

Main Results:

• MRSA actively prevents mitochondrial recruitment to its vacuole, requiring CASP11.
• CASP11 deficiency enhances mitochondrial association with MRSA vacuoles.
• Antimycin A-induced mitochondrial superoxide aids MRSA eradication in CASP11-deficient cells.
• CASP11 absence reduces caspase-1, IL-1β, and caspase-7 cleavage, and CXCL1/KC production.

Conclusions:

• CASP11 promotes MRSA persistence by facilitating the dissociation of mitochondria from MRSA-containing vacuoles.
• Targeting this CASP11-mediated pathway offers a potential strategy for MRSA eradication.