New Research Highlights How Skin Bacteria Help Protect Against Sun Damage

Recent scientific research has shed light on the pivotal role our skin's microbiome plays in safeguarding us from the harmful effects of ultraviolet (UV) radiation from the sun. The study, published in the Journal of Investigative Dermatology, demonstrates that certain skin bacteria can metabolize cis-urocanic acid—a byproduct of UV exposure—using an enzyme called urocanase. This metabolic process significantly reduces the immunosuppressive properties of cis-urocanic acid, thereby enabling the skin to better regulate its immune response after sun exposure.

The skin's microbiome, a complex ecosystem comprising bacteria, fungi, and viruses, varies considerably depending on the specific area of the body and is shaped by factors like age, environment, hygiene, and climate. Commensal microbes, or beneficial microorganisms, adapt their metabolism based on skin nutrients and produce molecules that influence skin health and immune functions.

Lead researcher VijayKumar Patra explains that previous studies have shown UV radiation impacts skin immunity and that the microbiome also modulates these responses. By integrating microbiome sequencing, immune testing, and animal models, the researchers found that specific bacteria metabolize the UV-induced molecule cis-urocanic acid, reducing its ability to suppress immune responses. This microbial activity helps fine-tune the skin’s response to UV exposure.

The findings reveal an intriguing interaction between sunscreen ingredients, UV products, and skin microbes, particularly in the outermost skin layer, the stratum corneum. Co-investigator Marc Vocanson notes that this is the first evidence of a direct metabolic connection between UV radiation, host molecules, and bacterial behavior affecting immune function.

This research opens new horizons for personalized sun protection strategies that consider the skin microbiome. Future treatments could involve topical agents designed to modify microbial activity, potentially enhancing UV protection or controlling immune responses for skin conditions and phototherapy. Experts believe understanding these microbe-host interactions could revolutionize approaches to skin health, cancer prevention, and immune regulation, emphasizing the skin as a dynamic, metabolically active barrier.

Overall, the study highlights that skin bacteria are not passive bystanders but active regulators of our skin’s defense mechanisms against sunlight, promising innovative avenues for therapies and preventive measures.

Source: https://medicalxpress.com/news/2025-05-reveals-skin-bacteria-bad-effects.html