Aspergillus fumigatus melanin manipulates the cargo and kinetics of neutrophil-derived extracellular vesicles

ABSTRACT: Neutrophil-derived extracellular vesicles have regained scientific interest as potent ‘wireless’ modulators with pleiotropic effects on the immune system. A few studies have addressed their role in the context of microbial pathogenesis showing their bacteriostatic effects against Staphylococcus aureus in vitro and their potential as diagnostic markers in the onset of bacterimic sepsis in vivo. Here, we provided first insights into the vesicle release driven by the clinically relevant pathogenic fungus Aspergillus fumigatus that causes invasive infections in immunocompromised individuals worldwide often with a lethal outcome. Neutrophils, stimulated with fungal spores, potently produced vesicles that we refer as anti-fungal extracellular vesicles (afEVs). We revealed that the conidial surface pigment of A. fumigatus dihydroxynaphthalene (DHN) melanin - a well known fungal virulence factor - is a key ‘switch-on/off’ governing vesicle production. We profiled the kinetics of afEV formation and showed that DHN-melanin interferes with the vesicle number, vesicle surface maturation markers such as CD11b, CD63 and CD177 and governs the enrichment of distinct afEV subpopulations unrelated to apoptosis. Simultaneously we tracked down the fate of neutrophils during afEV formation and observed mulivesicular body formation that led to active export of CD11b, CD63 and CD177 by shedding from the surface of neutrophils onto the surface afEVs. By dissecting the proteome cargo of afEVs produced against wild-type and melanin-free conidia we verified that DHN-melanin also manipulates the type of cargo neutrophils accumulate in the vesicles upon confronting conidia with different cell wall integrity. afEVs contained higher amounts of antimicrobial peptides than spontaneously released EVs from uninfected neutrophils. Last but not least afEVs exhibit fungistatic effects and also modulate cell wall morphogenesis of hyphae.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Neosartorya Fumigata (aspergillus Fumigatus)

TISSUE(S): Conidium, Neutrophil

SUBMITTER: Thomas Krüger  

LAB HEAD: Axel A. Brakhage

PROVIDER: PXD005994 | Pride | 2019-05-17

REPOSITORIES: Pride