Phosphatidylcholine biosynthesis pathways in: functional interplay and impact on virulence.

Abstract

As fungal diseases emerge, new studies aim to understand how different metabolic pathways, including the biosynthesis of phospholipids, influence the fungal pathogenicity. Therefore, to investigate the role of phosphatidylcholine (PC) in the biology of the human fungal pathogen, a double mutant lacking(phosphatidylethanolamine methyltransferase) from thepathway, and(choline phosphate cytidylyltransferase) from the salvage Kennedy pathway was generated usingPCR coupled with biolistic technique for gene deletion. Phenotypic and virulence assays were performed, including growth viability in minimal nutrient, melanization, capsule expansion and titanization, lipid droplet analysis andinfection in larval and murine models. The double mutant () exhibited normal growth in complex medium, but displayed severe growth defects and loss of viability under nutrient-limited conditions. Supplementation with L-α-glycerophosphorylcholine (GPC), PC or sorbitol fully restores growth, suggesting compensation of GPC-dependent reacylation pathway. Disruption of PC biosynthesis affected important virulence traits, including capsule formation, melanization, and titan cell development, and increased susceptibility to membrane stresses. In vivo, in both theand murine models,was hypovirulent with reduced brain colonization. Other studies withand, another pathogenic yeast, showed no impact in deletion of eitheroralone for virulence and pathogenicity. Therefore, these findings highlight the critical role of PC biosynthesis for maintaining membrane integrity, morphological plasticity and host dissemination of.