Atopic Dermatitis-like mouse model using early inoculation of patient-derived S. aureus together with MC903

Area of Science:

• Microbiology
• Immunology
• Dermatology

Background:

• Staphylococcus aureus (S. aureus) exacerbates atopic dermatitis (AD), but strain-specific pathogenicity is poorly understood.
• Existing mouse models often lack clinical relevance and fail to incorporate patient-derived S. aureus strains.
• Limited models exist for studying early-stage AD and manipulating S. aureus in vivo.

Purpose of the Study:

• To investigate the inflammatory potential of clinical S. aureus and S. epidermidis isolates from AD patients in a mouse model.
• To assess the impact of pathogenic S. aureus strains within a type 2 immune environment mimicking AD.
• To explore the role of virulence factors and genomic variation in S. aureus-induced inflammation.

Main Methods:

• Utilized a mouse model to evaluate inflammatory responses to clinical S. aureus and S. epidermidis isolates from AD patients.
• Administered MC903 to induce a type 2 immune environment, then introduced pathogenic S. aureus strains.
• Analyzed bacterial colonization, skin inflammation, and immune responses (type 1, 2, 17/22).
• Examined virulence factor expression and genomic variation in S. aureus strains.

Main Results:

• Clinical S. aureus strains exhibited significant variability in eliciting inflammation, linked to virulence factors and genomic differences.
• S. epidermidis strains induced mild, consistent inflammation with less strain-level variability.
• In a type 2 immune environment, pathogenic S. aureus enhanced colonization, increased inflammation, and promoted mixed immune responses.
• These combined effects were more pronounced than individual treatments alone.

Conclusions:

• Clinical S. aureus strains from AD patients differ in their capacity to modulate skin inflammation, especially in type 2-skewed environments.
• Incorporating clinically relevant S. aureus isolates into early-stage in vivo models can improve understanding of AD immunopathology.
• Findings support the development of microbiome-targeted therapeutic strategies for atopic dermatitis.