New insights into the role of Cutibacterium acnes-derived extracellular vesicles in inflammatory skin disorders

Abstract

Abstract Background: Cutibacterium acnes (C. acnes) is one of the most prevalent bacteria that forms the human skin microbiota. Specific phylotypes of C. acnes have been linked to acne vulgaris development, while others have been found in individuals with healthy skin. In this scenario, bacterial extracellular vesicles (EVs) play an interkingdom communication role with the host. The purpose of this study was to examine the impact of EVs generated by various phylotypes of C. acnes on inflammation and sebum production using different in vitro skin models. Results: The main findings of this study reveal that the proteomic profile of the cargo embodied in the EVs reflects distinct characteristics of the different C. acnes phylotypes in terms of lifestyle, survival, and virulence. The in vitro skin models showed an extended pro-inflammatory modulation of A1 EVs consistently triggering the activation of the inflammation-related factors IL-8, IL-6, TNFαand GM-CSF, in comparison to H1 and H2. Additionally, an acne-prone skin model utilizing PCi-SEB and arachidonic acid (AA) as a sebum inductor, was employed to investigate the impact of C. acnes EVs on sebum regulation. The results indicated that all three types of EVs significantly inhibited sebum production after a 24-hour treatment period, with H1 EVs exhibiting the most pronounced inhibitory effect when compared to the positive control. Conclusions: The results of this study highlight the protective nature of C. acnes H1 EVs and their potential as a natural treatment option for alleviating symptoms associated with inflammation and oily skin.