The human pathobiont Malassezia furfur secreted protease Mfsap1 regulates cell dispersal and exacerbates skin inflammation

Abstract

Malassezia form the dominant eukaryotic microbial community on the human skin. The Malassezia genus possesses a repertoire of secretory hydrolytic enzymes involved in protein and lipid metabolism which alter the external cutaneous environment. The exact role of most Malassezia secreted enzymes, including those in interaction with the epithelial surface, is not well characterized. In this study, we compared the expression level of secreted proteases, lipases, phospholipases, and sphingomyelinases of Malassezia globosa in healthy subjects and seborrheic dermatitis or atopic dermatitis patients. We observed upregulated gene expression of the previously characterized secretory aspartyl protease MGSAP1 in both diseased groups, in lesional and non-lesional skin sites, as compared to healthy subjects. To explore the functional roles of MGSAP1 in skin disease, we generated a knockout mutant of the homologous protease MFSAP1 in the genetically tractable Malassezia furfur . We observed the loss of MFSAP1 resulted in dramatic changes in the cell adhesion and dispersal in both culture and a human 3D reconstituted epidermis model. In a murine model of Malassezia colonization, we further demonstrated Mfsap1 contributes to inflammation as observed by reduced edema and inflammatory cell infiltration with the knockout mutant versus wildtype. Taken together, we show that this dominant secretory Malassezia aspartyl protease has an important role in enabling a planktonic cellular state that can potentially aid in colonization and additionally as a virulence factor in barrier-compromised skin, further highlighting the importance of considering the contextual relevance when evaluating the functions of secreted microbial enzymes.

Transcriptional Interplay between Malassezia restricta and Staphylococcus Species Co-Existing in the Skin Environment

“…Recent interesting study reported that MGSAP1 was upregulated in atopic and seborrheic dermatitis skin. Furthermore, this SAP play a pivotal role in fungal skin colonization and tissue inflammation in diseased skin tissue [ 24 ]. In our present work, pH is another factor which could control the expression of SAP.…”

Frequent transitions in mating-type locus chromosomal organization inMalasseziaand early steps in sexual reproduction

“…S18 ). A recent study revealed that MFSAP2 expression is essentially undetectable in M. furfur CBS14141 WT, whereas MFSAP1 (GLX27_000216), which lies adjacent to MFSAP2 in the genome, is the most highly expressed SAP gene (46). Our data confirmed that MFSAP1 is highly expressed but not differentially expressed in both mutant and WT strains (GLX27_000216; Datasets S2 and S3).…”

“…Our data confirmed that MFSAP1 is highly expressed but not differentially expressed in both mutant and WT strains (GLX27_000216; Datasets S2 and S3). M. furfur MFSAP1 seems to play an essential role in fungal skin colonization and tissue inflammation, and a compensatory expression of the other SAP genes was not observed when MFSAP1 was deleted (46). Therefore, the increased expression of MFSAP2 and three lipase genes in the A on B off and “solo” strains could represent a life cycle stage-specific response possibly associated with hyphal growth during sexual development.…”

“…Furthermore, we found that both M. furfur A on B off and “solo” strains have markedly increased expression of MFSAP2 , which encodes one of nine putative secretory aspartyl proteases. Recent studies demonstrated that MFSAP1 , which lies adjacent to MFSAP2 , is the dominant secretory aspartyl protease in M. furfur WT and has critical roles in controlling cell adhesion during colonization and inducing inflammation in barrier-compromised skin (46). Therefore, the Malassezia hyphal growth detected associated with initiation of sexual development may have important roles in skin colonization and inflammation, especially in patients with impaired skin barriers, and thus affect its pathogenicity and virulence.…”

More than Just Protein Degradation: The Regulatory Roles and Moonlighting Functions of Extracellular Proteases Produced by Fungi Pathogenic for Humans

“…For Microsporum canis Sub3 subtilisin, a cell-mediated immune response was demonstrated in the experimentally infected guinea pig model, and for the extracellular metalloproteinase Mep3 of the same species, an antibody response was observed, although neither protease was protective in the vaccination trials [ 111 , 112 , 113 , 114 ]. In addition, the secretory aspartyl protease Mfsap1 from an opportunistic cutaneous pathogen Malassezia furfur has been recently indicated as strongly contributing to the development of inflammation in barrier-compromised murine skin, and the mechanisms may involve a direct interaction of protease with the host, or the Mfsap1-dependent modification of fungal cell surface hydrophobicity [ 115 ]. An endemic fungus Paracoccidioides brasiliensis has also been reported to produce serine and cysteine proteases that trigger IL-6 and IL-8 secretion by lung epithelial cells in PAR1- and PAR2-dependent manners [ 116 ], and representatives of the former group of Paracoccidioides proteases have also been demonstrated to have antigenic properties [ 117 ].…”