Proteomics Reveals AP-2 Complex Depletion Suppressing Listeria monocytogenes Intracellular Replication

Area of Science:

• Microbiology
• Cell Biology
• Immunology

Background:

• Listeria monocytogenes is a zoonotic pathogen causing significant infections.
• Innate immune cells like macrophages and dendritic cells are crucial for controlling L. monocytogenes.
• Understanding host-pathogen interactions is key to developing new treatments.

Purpose of the Study:

• To investigate the role of the AP-2 adaptor complex in L. monocytogenes infection.
• To identify specific AP-2 subunits involved in intracellular bacterial replication.
• To explore the potential of the AP-2 complex as a therapeutic target.

Main Methods:

• Established an in vitro infection model using various cell lines (Raw264.7, DC2.4, HeLa, Caco-2).
• Utilized proteomics to identify interacting AP-2 complex subunits.
• Employed CRISPR/Cas9 gene editing to create knockout cell lines for specific AP-2 subunits.

Main Results:

• L. monocytogenes infection upregulates the expression of Ap2s1, a subunit of the AP-2 complex.
• Proteomic analysis identified Ap2m1 and Ap2a2 as cooperating subunits.
• Silencing Ap2m1, Ap2a2, or Ap2s1 significantly inhibited intracellular bacterial growth.

Conclusions:

• The AP-2 adaptor complex, specifically subunits Ap2s1, Ap2m1, and Ap2a2, is essential for L. monocytogenes intracellular replication.
• AP-2 facilitates post-phagosomal cytosolic replication, independent of bacterial spread.
• The AP-2 complex represents a promising host-directed therapeutic target against L. monocytogenes infections, including antibiotic-resistant strains.