Bacterial extracellular vesicles: A new way to decipher host‐microbiota communications in inflammatory dermatoses

Abstract

Bacterial extracellular vesicles (EVs) are bilayered lipid membrane structures, bearing integral proteins and able to carry diverse cargo outside the cell to distant sites. In microorganisms, EVs carry several types of molecules: proteins, glycoproteins, mRNAs and small RNA species, as mammalian EVs do, but also carbohydrates. Studying EVs opens a whole new world of possibilities to better understand the interplay between host and bacteria crosstalks, although there are still many questions to be answered in the field, especially when it comes to microbiota-derived EVs. In this review, we propose to summarize and analyse the current literature about bacterial EVs and possible clinical applications, through answering three main questions: (a) What are bacterial EVs? (b) What are EV impacts on skin inflammatory disease physiopathology? (iii) What are the possible and expected clinical applications of EVs to treat inflammatory skin diseases? K E Y W O R D S cell-to-cell communication, exosomes, extracellular vesicles, microbiota, probiotics, skin microbiota | 23 DAGNELIE Et AL.

The Skin Microbiome: A New Actor in Inflammatory Acne

“…Moreover, the vesicles induced a significant rise in inflammatory cytokine IL-8 and granulocyte macrophage colony-stimulating factor (GM-CSF) levels [20]. Indeed, bacterial extracellular vesicles were recently shown to be implicated in intra-and interspecies cell-tocell communication and to play a pro-inflammatory role in several human diseases, including acne [21]. Consequently, inhibiting the release of C. acnes extracellular vesicles or targeting their signaling pathways could represent an alternative way of limiting acne development and severity [20].…”

Caveolin‐1 as a possible target in the treatment for acne

“…This pathogen also constitutively releases extracellular vesicles, which can induce innate immunity and acne-like phenotype in human epidermal keratinocytes. [42,43] Similar mechanism based on the S. aureus-derived extracellular vesicles was stated to be an important factor in pathogenesis of atopic dermatitis. [44] Cutibacterium acnes produce coproporphyrin III, which arises from haeme synthesis.…”

“…Cutibacterium acnes interacts with the skin not only through invading the host cells. This pathogen also constitutively releases extracellular vesicles, which can induce innate immunity and acne‐like phenotype in human epidermal keratinocytes . Similar mechanism based on the S. aureus ‐derived extracellular vesicles was stated to be an important factor in pathogenesis of atopic dermatitis …”

Cross-Kingdom Extracellular Vesicles EV-RNA Communication as a Mechanism for Host–Pathogen Interaction

“…Bacterial vesicles were introduced intraperitonially in mice that afterwards presented symptoms of sepsis-like inflammation and eventually died, highlighting that the EVs were sufficient to trigger the host inflammatory response (Park et al, 2018). Additionally, it has been described that the pathogen vesicle formation can be affected by the antibiotic choice in the treatment of sepsis-a great contributor to treatment success-making it even more important to understand the phenomena surrounding the EV-cargo-microbehost system (Dagnelie et al, 2019).…”