A human endothelial cell membrane protein that binds Staphylococcus aureus in vitro

Area of Science:

• Microbiology
• Cell Biology
• Biochemistry

Background:

• Staphylococcus aureus (S. aureus) is a significant pathogen.
• Understanding S. aureus adherence to host cells is critical for infection control.
• Endothelial cells form the inner lining of blood vessels and are a key interface for pathogens.

Purpose of the Study:

• To investigate the specific molecular interactions between S. aureus and human endothelial cells.
• To identify and characterize endothelial cell surface components involved in S. aureus binding.
• To elucidate the role of these interactions in S. aureus colonization and invasion.

Main Methods:

• Developed an in vitro model using confluent endothelial cell monolayers.
• Utilized a pH-dependent affinity technique for isolating membrane components.
• Characterized the isolated component using enzymatic and labeling studies ([35S]Methionine, [125I]iodine).
• Performed functional binding assays with immobilized protein and S. aureus.

Main Results:

• S. aureus binding to endothelial cells was specific, saturable, and dependent on dose and time.
• A 50-kD endothelial cell membrane protein was isolated and purified.
• The protein was trypsin-sensitive, periodate-insensitive, and synthesized/expressed on the cell surface.
• The purified protein specifically bound S. aureus, and its preincubation reduced bacterial adherence to endothelial cells.

Conclusions:

• Identified a 50-kD endothelial cell surface protein that mediates S. aureus adherence.
• This protein plays a significant role in the interaction between S. aureus and the endovascular surface.
• Targeting this interaction could offer novel strategies to prevent S. aureus colonization and invasion.