Identification of small molecules that disrupt vacuolar function in the pathogen Candida albicans.
The fungal vacuole is a large acidified organelle that performs a variety of cellular functions. At least a sub-set of these functions are crucial for pathogenic species of fungi, such as Candida albicans, to survive within and invade mammalian tissue as mutants with severe defects in vacuolar biogenesis are avirulent. We therefore sought to identify chemical probes that disrupt the normal function and/or integrity of the fungal vacuole to provide tools for the functional analysis of this organelle as well as potential experimental therapeutics. A convenient indicator of vacuolar integrity based upon the intracellular accumulation of an endogenously produced pigment was adapted to identify Vacuole Disrupting chemical Agents (VDAs). Several chemical libraries were screened and a set of 29 compounds demonstrated to reproducibly cause loss of pigmentation, including 9 azole antifungals, a statin and 3 NSAIDs. Quantitative analysis of vacuolar morphology revealed that (excluding the azoles) a sub-set of 14 VDAs significantly alter vacuolar number, size and/or shape. Many C. albicans mutants with impaired vacuolar function are deficient in the formation of hyphal elements, a process essential for its pathogenicity. Accordingly, all 14 VDAs negatively impact C. albicans hyphal morphogenesis. Fungal selectivity was observed for approximately half of the VDA compounds identified, since they did not alter the morphology of the equivalent mammalian organelle, the lysosome. Collectively, these compounds comprise of a new collection of chemical probes that directly or indirectly perturb normal vacuolar function in C. albicans.
Department of Clinical Pharmacy, Division of Clinical and Experimental Therapeutics, College of Pharmacy, University of Tennessee Health Sciences Center, Memphis, Tennessee, United States of America.
Helene
H
Tournu
Department of Medicine, Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, Louisiana, United States of America.
Jennifer
J
Carroll
Department of Medicine, Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, Louisiana, United States of America.
Brian
B
Latimer
Department of Medicine, Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, Louisiana, United States of America.
Ana-Maria
AM
Dragoi
Department of Medicine, Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, Louisiana, United States of America.
Samantha
S
Dykes
Department of Medicine, Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, Louisiana, United States of America.
James
J
Cardelli
Department of Clinical Pharmacy, Division of Clinical and Experimental Therapeutics, College of Pharmacy, University of Tennessee Health Sciences Center, Memphis, Tennessee, United States of America.
Tracy L
TL
Peters
Department of Microbiology, Immunology and Parasitology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America.
Karen E
KE
Eberle
Department of Clinical Pharmacy, Division of Clinical and Experimental Therapeutics, College of Pharmacy, University of Tennessee Health Sciences Center, Memphis, Tennessee, United States of America.
Glen E
GE
Palmer
D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D002460:Cell Line; D004396:Coloring Agents; D003374:Coumarins; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D009154:Mutation; D010858:Pigmentation / Q000235:genetics; D010860:Pigments, Biological / Q000235:genetics / Q000378:metabolism; D014617:Vacuoles / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure
C453681:7-amino-4-chloromethylcoumarin; D000935:Antifungal Agents; D004396:Coloring Agents; D003374:Coumarins; D010860:Pigments, Biological