Apoptosis-like cell death of cryptococcus neoformans mediated by staphylococcus aureus contact

Abstract

Co-culture of the fungal pathogen Cryptococcus neoformans with Staphylococcus aureus results in the death of the fungus, caused by the adherence to the latter. The present study found that the molecules responsible for this adherence were capsular glucuronoxylomannan (GXM) (present on C. neoformans) and a glycolytic enzyme triosephosphate isomerase (TPI) (present on S. aureus). The mannan backbone of GXM and purified TPI interacted in vitro. GXM-bound TPI molecules were identified by immunoelectron microscopy. The death of C. neoformans was accompanied by decreased actin turnover, increased accumulation of reactive oxygen species, and DNA fragmentation. This process may also be influenced by the Rho/Rho-associated coiled-coil-forming kinase (ROCK) pathway and enhanced expression of voltage-dependent ion-selective channels. Taken together, these results suggest that Rho-ROCK signaling may play a role via the mitochondrial pathway in the induction of C. neoformans apoptosis-like cell death after its adherence to S. aureus adherence.