Poster Presentation Australasian Extracellular Vesicles Conference 2018

Quantitative proteomic analysis of extracellular vesicles fromĀ Candida albicans biofilms. (#80)

Charlotte Dawson 1 , Mark Bleackley 1 , Marilyn Anderson 1
  1. La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia

The dimorphic pathogenic fungus Candida albicans is the leading cause of invasive fungal infections. The high morbidity and mortality associated with Candida infections are linked to its ability to form biofilms. Yeast-form Candida is known to release extracellular vesicles (EVs) containing protein and RNA. However, it is unknown whether EVs are released by Candida biofilms.

A major issue hindering the study of fungal EVs is a lack of defined EV protein markers. Only three tetraspanin families have been identified in fungi, none of which are orthologous to CD9, CD63, or CD81. Additionally, orthologs of the ESCRT proteins TSG101 and ALIX are either not enriched or not detected in fungal EVs. Hence, there is a need to identify new fungal-specific EV markers to facilitate fungal EV research.

We have performed label-free quantitative proteomics on EVs and cell lysates derived from Candida grown in the yeast form and as a biofilm. These samples were compared to identify proteins significantly enriched in yeast and biofilm EVs.

EVs from yeast-form Candida were enriched in proteins involved in glycosylation, ergosterol biosynthesis, and pathogenesis. Biofilm EVs were enriched in proteins involved in pathogenesis, adhesion, and biofilm formation. The potential EV marker proteins identified included GTPases and plasma membrane proteins.

We have demonstrated that EVs are released by Candida biofilms and that their protein cargo is distinct from yeast-form Candida EVs. Future work will focus on validating the potential new EV protein markers and understanding the potential roles for EVs in C. albicans pathogenesis.