The skin consists of the epidermis, dermis, and hypodermis or subcutaneous tissue. The hypodermis is the predominant site of infection, which causes redness, swelling, and pain with potentially serious health problems. How immune cells prevent or promote S. aureus infection is unclear. The authors of this study found that hypodermal macrophages (HDMs) enhance tissue clearance of the extracellular matrix component hyaluronic acid, which provides S. aureus with an opportunity to hijack the tissue and establish infection. HDMs did so through cell-autonomous insulin-like growth factor 1-driven expression of the hyaluronic acid receptor LYVE-1.
What is exciting about this article?
The findings show that macrophages and stroma communicate intricately to support skin structural integrity. It also confirms the role of macrophages in the regulation of hyaluronic acid. These functions of hypodermal macrophages may be harnessed to limit skin infection.
Research reported in this publication was supported by the Intramural Research Program of the NIHʼs National Institute of Arthritis and Musculoskeletal and Skin Diseases.