Small Molecule Inhibitors Limit Endothelial Cell Invasion by Staphylococcus aureus.

Area of Science:

• Microbiology
• Cell Biology
• Infectious Diseases

Background:

• Staphylococcus aureus is a major cause of severe infections like sepsis, endocarditis, and pneumonia.
• Pathogenic S. aureus strains can invade host cells, worsening patient prognosis.
• Host cell protein CDC42 was previously identified as crucial for S. aureus endothelial cell invasion.

Purpose of the Study:

• To investigate the effect of a CDC42 inhibitor, ML 141, on S. aureus invasion and pathogenesis.
• To explore the mechanisms by which ML 141 inhibits bacterial entry.
• To evaluate novel CDC42 inhibitors for therapeutic potential against invasive S. aureus infections.

Main Methods:

• Treatment of endothelial cells with ML 141, a CDC42 inhibitor.
• Dose-response and reversibility studies of ML 141 effects.
• Analysis of actin remodeling and bacterial binding to fibronectin.
• Synthesis and evaluation of ML 141 structural analogs (RSM series).

Main Results:

• ML 141 significantly decreased S. aureus invasion and pathogenesis in a dose-dependent and reversible manner.
• Inhibition involved reduced actin remodeling, a process critical for bacterial uptake.
• ML 141 diminished bacterial binding to fibronectin complexes, a key invasion pathway.
• Novel RSM analogs were identified that inhibit invasion without cytotoxicity or bactericidal effects.

Conclusions:

• Targeting host CDC42 with inhibitors like ML 141 is a promising strategy to combat invasive S. aureus infections.
• Inhibiting CDC42 disrupts bacterial entry by interfering with host cell actin dynamics and bacterial adhesion.
• Development of adjunctive therapies targeting host CDC42 could mitigate the severity of invasive S. aureus disease.