EGFR/FAK and c-Src signalling pathways mediate the internalisation of Staphylococcus aureus by osteoblasts

Area of Science:

• Microbiology
• Cell Biology
• Orthopedics

Background:

• Osteomyelitis, a persistent bone infection, is often caused by Staphylococcus aureus.
• The internalisation of S. aureus into osteoblasts is crucial for disease recurrence, but the underlying mechanisms are poorly understood.

Purpose of the Study:

• To elucidate the mechanisms of Staphylococcus aureus internalisation into osteoblasts.
• To investigate the role of specific signaling pathways in this process.
• To identify potential therapeutic targets for chronic osteomyelitis.

Main Methods:

• In vivo studies using a mouse model of haematogenous osteomyelitis.
• In vitro experiments with osteoblastic MC3T3 cells and S. aureus.
• Analysis of intracellular bacterial presence and bone loss.
• Investigation of signaling pathways including epidermal growth factor receptor (EGFR), focal adhesion kinase (FAK), and c-Src.

Main Results:

• Intracellular S. aureus was detected in osteoblasts in a mouse model and in vitro.
• Blocking extracellular bacteria partially reduced bone loss, indicating the significance of intracellular bacteria.
• S. aureus invasion activated EGFR/FAK and c-Src signaling pathways in a time-dependent manner.
• Inhibition of EGFR/FAK or c-Src signaling significantly decreased S. aureus internalisation rates.

Conclusions:

• Staphylococcus aureus internalisation into osteoblasts is a key factor in osteomyelitis persistence.
• The EGFR/FAK and c-Src signaling pathways are critical mediators of S. aureus osteoblast internalisation.
• Targeting these signaling pathways presents a promising adjunctive therapeutic approach for chronic S. aureus osteomyelitis.