EDNA-Mediated Cutaneous Protection Against UVB Damage Conferred by Staphylococcal Epidermal Colonization.

Sapir Ron-Doitch,Danielle Duanis-Assaf,Dalit Amar,Doron Steinberg,Yoram Soroka,Ron Kohen,Marina Frušić-Zlotkin

doi:10.3390/microorganisms9040788

Sapir Ron-Doitch, Danielle Duanis-Assaf + Show 5 more

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https://doi.org/10.3390/microorganisms9040788

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Abstract

The human skin is a lush microbial habitat which is occupied by a wide array of microorganisms. Among the most common inhabitants are Staphylococcus spp., namely Staphylococcus epidermidis and, in ≈20% of healthy individuals, Staphylococcus aureus. Both bacteria have been associated with cutaneous maladies, where they mostly arrange in a biofilm, thus achieving improved surface adhesion and stability. Moreover, our skin is constantly exposed to numerous oxidative environmental stressors, such as UV-irradiation. Thus, skin cells are equipped with an important antioxidant defense mechanism, the Nrf2–Keap1 pathway. In this work, we aimed to explore the morphology of S. aureus and S. epidermidis as they adhered to healthy human skin and characterize their matrix composition. Furthermore, we hypothesized that the localization of both types of bacteria on a healthy skin surface may provide protective effects against oxidative stressors, such as UV-irradiation. Our results indicate for the first time that S. aureus and S. epidermidis assume a biofilm-like morphology as they adhere to ex vivo healthy human skin and that the cultures’ extracellular matrix (ECM) is composed of extracellular polysaccharides (EPS) and extracellular DNA (eDNA). Both bacterial cultures, as well as isolated S. aureus biofilm eDNA, conferred cutaneous protection against UVB-induced apoptosis. This work emphasized the importance of skin microbiota representatives in the maintenance of a healthy cutaneous redox balance by activating the skin’s natural defense mechanism.

Highlights

IntroductionThe human skin is the largest interface of our body with its surroundings and as such, it possesses many important physiological roles [1]
Introduction published maps and institutional affilThe human skin is the largest interface of our body with its surroundings and as such, it possesses many important physiological roles [1]
We aimed to explore the hypothesis that the cutaneous residents S. aureus and S. epidermidis portray an important role in skin physiology in a novel context, protection against environmental stressors, and UVB exposure as an example

Summary

Introduction

The human skin is the largest interface of our body with its surroundings and as such, it possesses many important physiological roles [1]. It is home to a milieu of microorganisms: viruses, bacteria, and fungi, which assemble a distinct ecosystem and greatly affect the cutaneous physiology [2]. Two highly explored positive effects that are attributed to cutaneous microbiota are the competitive exclusion of pathogens and immune modulation and training properties [3]. Among the Staphylococcus genus, one of the most abundant and well-characterized skin commensal is Staphylococcus epidermidis [2,4], while Staphylococcus aureus is part of the normal cutaneous flora of about 20% of healthy individuals [5]. S. aureus is a cutaneous inhabitant, which is notoriously known as a very common opportunistic pathogen. It has been linked to several cutaneous diseases, iations

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