The role of macrophages in S. aureus colonization of inflammatory skin diseases

01.05.2025 bis 30.04.2028

Atopic dermatitis and psoriasis are inflammatory skin diseases that affect up to 10% of the world's population. Psoriasis and atopic dermatitis are both triggered by a specific pathological T cell immune response with a predominance of TH1 or TH2 polarized T cells, respectively. It is thought that this T cell imbalance influences the higher predisposition to S. aureus colonization in atopic dermatitis patients, as they are often pathologically colonized with S. aureus in contrast to psoriasis patients. Tissue-resident macrophages are important for tissue homeostasis and remodeling and are key players in the inflammatory immune response of the skin and in the primary defense against pathogens. We hypothesize that skin-resident macrophages orchestrate the decision toward type 1 or type 2 immune cell responses in psoriasis and atopic dermatitis patients, respectively, thereby modulating susceptibility to S. aureus skin colonization. Using advanced in vitro and in vivo human and mouse models of psoriasis, atopic dermatitis and infection, this project aims to combine our expertise in innate immune response against S. aureus infection and advanced microscopic imaging to decipher (i) how skin-resident macrophages orchestrate the antibacterial and inflammatory TH1 and TH2 immune responses, (ii) how S. aureus evades macrophage clearance, and (iii) whether macrophages can be directed to limit skin inflammation and eliminate S. aureus in AD skin.