title: Salivary histatin 5 induces non-lytic release of ATP from Candida albicans leading to cell death.
abstract: Salivary histatins are potent in vitro antifungal proteins and have promise as therapeutic agents against oral candidiasis. We performed pharmacological studies directed at understanding the biochemical basis of Hst 5 candidacidal activity. Three inhibitors of mitochondrial metabolism: carbonyl cyanide p-chlorophenylhydrazone, dinitrophenol, and azide inhibited Hst 5 killing of Candida albicans, while not inhibiting cellular ATP production. In contrast, Hst 5 caused a drastic reduction of C. albicans intracellular ATP content, which was a result of an efflux of ATP. Carbonyl cyanide p-chlorophenylhydrazone, dinitrophenol, and azide inhibited Hst 5-induced ATP efflux, thus establishing a correlation between ATP release and cell killing. Furthermore, C. albicans cells were respiring and had polarized membranes at least 80 min after ATP release, thus implying a non-lytic exit of cellular ATP in response to Hst 5. Based on evidence that transmembrane ATP efflux can occur in the absence of cytolysis through a channel-like pathway and that released ATP can act as a cytotoxic mediator by binding to membrane purinergic receptors, we evaluated whether extracellular ATP released by Hst 5 may have further functional role in cell killing. Consistent with this hypothesis, purinergic agonists BzATP and adenosine 5'O-(thiotriphosphate) induced loss of C. albicans cell viability and purinergic antagonists prevented Hst 5 killing.
authors.affiliation: Department of Oral Biology, School of Dental Medicine, State University of New York at Buffalo, Buffalo, New York 14214, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Koshlukova
authors.forename: T L
authors.initials: TL
authors.lastname: Lloyd
authors.forename: M W
authors.initials: MW
authors.lastname: Araujo
authors.forename: M
authors.initials: M
authors.lastname: Edgerton
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D000935:Antifungal Agents / Q000378:metabolism*; D001386:Azides / Q000494:pharmacology; D002176:Candida albicans / Q000187:drug effects / Q000378:metabolism*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects; D004140:Dinitrophenols / Q000494:pharmacology; D054808:Histatins; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D008969:Molecular Sequence Data; D010101:Oxygen Consumption; D011983:Receptors, Purinergic / Q000378:metabolism; D012471:Salivary Proteins and Peptides / Q000378:metabolism*; D014475:Uncoupling Agents / Q000494:pharmacology
chemical_list: D000935:Antifungal Agents; D001386:Azides; D004140:Dinitrophenols; C068075:HTN3 protein, human; D054808:Histatins; D011983:Receptors, Purinergic; D012471:Salivary Proteins and Peptides; D014475:Uncoupling Agents; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000255:Adenosine Triphosphate