The Discovery of an Anti-Candida Xanthone with Selective Inhibition of Candida Albicans GAPDH

Objectives: This study aimed to discover novel antifungals targeting Candida albicans glyceraldehyde-3phosphate dehydrogenase ( Ca GAPDH), have an insight into inhibitory mode, and provide evidence supporting Ca GAPDH as a target for new antifungals. Methods: Virtual screening was utilized to discover inhibitors of Ca GAPDH. The inhibitory effect on cellular GAPDH was evaluated by determining the levels of ATP, NAD, NADH, etc., as well as examining GAPDH mRNA and protein expression. The role of GAPDH inhibition in C. albicans was supported by drug affinity responsive target stability and overexpression experiments. The mechanism of Ca GAPDH inhibition was elucidated by Michaelis-Menten enzyme kinetics and site -specific mutagenesis based on docking. Chemical synthesis was used to produce an improved candidate. Different sources of GAPDH were used to evaluate inhibitory selectivity across species. In vitro and in vivo antifungal tests, along with anti-biofilm activity, were carried out to evaluate antifungal potential of GAPDH inhibitors. Results: A natural xanthone was identified as the first competitive inhibitor of Ca GAPDH. It demonstrated in vitro anti - C. albicans potential but also caused hemolysis. XP -W, a synthetic side -chain -optimized xanthone, demonstrated a better safety profile, exhibiting a 50 -fold selectivity for Ca GAPDH over human GAPDH. XP -W also exhibited potent anti-biofilm activity and displayed broad-spectrum anti- Candida activities in vitro and in vivo, including multi-azole-resistant C. albicans . Conclusions: These results demonstrate for the first time that Ca GAPDH is a valuable target for antifungal drug discovery, and XP -W provides a promising lead. (c) 2024 Elsevier Ltd and International Society of Antimicrobial Chemotherapy. All rights reserved.