The skin microbiome plays an important role in health and disease. Researchers have now substantiated that certain skin bacteria can protect us from the sun's ultraviolet (UV) radiation specifically by metabolizing cis-urocanic acid using an enzyme called urocanase. This enables the skin's ability to fine-tune how it responds to UV radiation The findings of the study in the Journal of Investigative Dermatology, published by Elsevier, provide a striking case study that demonstrates the ability of the skin microbiome to remodel host immune functions.
The skin hosts a vast ecosystem composed of millions of microorganisms, including bacteria, fungi, and viruses. The composition of the cutaneous microbiome is highly unique, complex, and varies greatly depending on the anatomical location. Commensal microbes, also known as normal microbiota or indigenous microbiota that live in a beneficial or neutral relationship without causing harm, adapt their metabolism to the resources available in their microenvironment, feeding on our skin's nutrients and producing various molecules that affect their environment and interact with our skin cells.
Lead investigator VijayKumar Patra, PhD, Centre International de Recherche en Infectiologie; Lyon, France, and Research Unit for Photodermatology, Medical University of Graz, Austria, explains, "To date, many internal and external factors have been identified that influence the composition of the skin microbiome. These include various individual parameters such as race, gender, age, hormone levels, diet, and hygiene, but environmental factors and the effects of occupation, pollution, and climate also have a major influence. We have known for a long time that UV radiation modulates immune responses directed against environmental antigens on the surface of the skin and, more recently, that the skin microbiome also plays a role in regulating these responses. What intrigued us was the idea that certain microbes could be actively involved in or even interfere with UV effects. The overlap between microbial metabolism and host immunity became the focus of our investigation."
