Lipidome analysis reveals antifungal polyphenol curcumin affects membrane lipid homeostasis

Abstract

This study shows that antifungal curcumin (CUR), significantly depletes ergosterol levels in Candida albicans. CUR while displaying synergy with fluconazole (FLC) lowers ergosterol. However, CUR alone at its synergistic concentration (lower than MIC₅₀), could not affect ergosterol contents. For deeper insight of CUR effects on lipids, we performed high throughput mass spectroscopy (MS) based lipid profiling of C. albicans cells. The lipidome analysis revealed that there were no major changes in phosphoglycerides (PGLs) composition following CUR treatment of Candida, however, significant differences in molecular species of PGLs were detected. Among major SPLs, CUR treatment resulted in the reduction of ceramide and accumulation of IPCs levels. The lipidome of CUR treated cells confirmed a dramatic drop in the ergosterol levels with a simultaneous accumulation of its biosynthetic precursors. This was further supported by the fact that the mutants defective in ergosterol biosynthesis (ERG2 and ERG11) and those lacking the transcription factor regulating ergosterol biosynthesis, UPC2, were highly susceptible to CUR. Our study first time shows that CUR, for its antifungal activity, targets and down regulates Δ^5,6 desaturase (ERG3) resulting in depletion of ergosterol. This results in parallel accumulation of ergosterol biosynthetic precursors, generation of reactive oxygen species (ROS) and cell death.