Outer membrane vesicles hijack TIM-1 for cellular uptake

Area of Science:

• Microbiology
• Cell Biology
• Immunology

Background:

• Outer membrane vesicles (OMVs) are bacterial nanoparticles involved in host-pathogen interactions.
• Mechanisms of OMV entry into host cells are not fully understood.
• OMVs have potential applications in vaccines and drug delivery.

Purpose of the Study:

• To elucidate the host cell receptors and mechanisms involved in OMV uptake.
• To identify specific host factors mediating bacterial OMV internalization.
• To explore therapeutic strategies targeting OMV-host interactions.

Main Methods:

• High-throughput screening of human transmembrane proteins for OMV binding.
• Functional assays including receptor overexpression and knockout.
• Antibody-mediated blockade of receptor-ligand interactions.
• Mechanistic studies on receptor-ligand binding and downstream effects.

Main Results:

• T-cell immunoglobulin and mucin-domain 1 (TIM-1) was identified as a key receptor for E. coli OMV uptake.
• TIM-1 overexpression enhanced OMV internalization; TIM-1 knockout/blockade reduced it.
• TIM-1 binds to OMV lipopolysaccharide (LPS) via its phosphatidylserine-binding domain.
• TIM-1-mediated OMV uptake triggers proinflammatory cytokine production.
• Multiple bacterial species' OMVs utilize TIM-1 for entry.

Conclusions:

• TIM-1 is a critical host receptor mediating the uptake of bacterial OMVs.
• Targeting the TIM-1-OMV interaction can modulate pathogenesis and inflammation.
• This finding provides a novel approach for developing antivirulence strategies and enhancing OMV-based therapies.