title: Oxidative stress-mediated antimalarial activity of plakortin, a natural endoperoxide from the tropical sponge Plakortis simplex.
abstract: Plakortin, a polyketide endoperoxide from the sponge Plakortis simplex has antiparasitic activity against P. falciparum. Similar to artemisinin, its activity depends on the peroxide functionality. Plakortin induced stage-, dose- and time-dependent morphologic anomalies, early maturation delay, ROS generation and lipid peroxidation in the parasite. Ring damage by 1 and 10 µM plakortin led to parasite death before schizogony at 20 and 95%, respectively. Treatment of late schizonts with 1, 2, 5 and 10 µM plakortin resulted in decreased reinfection rates by 30, 50, 61 and 65%, respectively. In both rings and trophozoites, plakortin induced a dose- and time-dependent ROS production as well as a significant lipid peroxidation and up to 4-fold increase of the lipoperoxide breakdown product 4-hydroxynonenal (4-HNE). Antioxidants and the free radical scavengers trolox and N-acetylcysteine significantly attenuated the parasite damage. Plakortin generated 4-HNE conjugates with the P. falciparum proteins: heat shock protein Hsp70-1, endoplasmatic reticulum-standing Hsp70-2 (BiP analogue), V-type proton ATPase catalytic subunit A, enolase, the putative vacuolar protein sorting-associated protein 11, and the dynein heavy chain-like protein, whose specific binding sites were identified by mass spectrometry. These proteins are crucially involved in protein trafficking, transmembrane and vesicular transport and parasite survival. We hypothesize that binding of 4-HNE to functionally relevant parasite proteins may explain the observed plakortin-induced morphologic aberrations and parasite death. The identification of 4-HNE-protein conjugates may generate a novel paradigm to explain the mechanism of action of pro-oxidant, peroxide-based antimalarials such as plakortin, artemisinins and synthetic endoperoxides.
authors.affiliation: Department of Oncology, University of Torino, Via Santena 5bis, 10126 Torino, Italy. Electronic address: olexii.skorokhod@unito.it.
authors.forename: Oleksii A
authors.initials: OA
authors.lastname: Skorokhod
authors.affiliation: Department of Oncology, University of Torino, Via Santena 5bis, 10126 Torino, Italy. Electronic address: denise.davalosschafler@unito.it.
authors.forename: Denise
authors.initials: D
authors.lastname: Davalos-Schafler
authors.affiliation: Department of Oncology, University of Torino, Via Santena 5bis, 10126 Torino, Italy. Electronic address: valentina.gallo@unito.it.
authors.forename: Valentina
authors.initials: V
authors.lastname: Gallo
authors.affiliation: Department of Oncology, University of Torino, Via Santena 5bis, 10126 Torino, Italy. Electronic address: elena.valente@unito.it.
authors.forename: Elena
authors.initials: E
authors.lastname: Valente
authors.affiliation: Department of Oncology, University of Torino, Via Santena 5bis, 10126 Torino, Italy. Electronic address: daniela.ulliers@unito.it.
authors.forename: Daniela
authors.initials: D
authors.lastname: Ulliers
authors.affiliation: Department of Oncology, University of Torino, Via Santena 5bis, 10126 Torino, Italy. Electronic address: agata.notarpietro@unito.it.
authors.forename: Agata
authors.initials: A
authors.lastname: Notarpietro
authors.affiliation: Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino Medical School, Via Nizza 52, 10126 Torino, Italy; Center for Experimental Research and Medical Studies (CeRMS), Città della Salute e della Scienza, Ospedale San Giovanni Battista, Via Cherasco 15, 10126 Torino, Italy. Electronic address: giorgia.mandili@unito.it.
authors.forename: Giorgia
authors.initials: G
authors.lastname: Mandili
authors.affiliation: Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino Medical School, Via Nizza 52, 10126 Torino, Italy; Center for Experimental Research and Medical Studies (CeRMS), Città della Salute e della Scienza, Ospedale San Giovanni Battista, Via Cherasco 15, 10126 Torino, Italy. Electronic address: franco.novelli@unito.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Novelli
authors.affiliation: Department of Pharmacy, University of Napoli 'Federico II', Via D. Montesano 49, 80131 Napoli, Italy. Electronic address: m.persico@unina.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Persico
authors.affiliation: Department of Pharmacy, University of Napoli 'Federico II', Via D. Montesano 49, 80131 Napoli, Italy. Electronic address: orazio.taglialatelascafati@unina.it.
authors.forename: Orazio
authors.initials: O
authors.lastname: Taglialatela-Scafati
authors.affiliation: Department of Oncology, University of Torino, Via Santena 5bis, 10126 Torino, Italy. Electronic address: paolo.arese@unito.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Arese
authors.affiliation: Department of Oncology, University of Torino, Via Santena 5bis, 10126 Torino, Italy. Electronic address: evelin.schwarzer@unito.it.
authors.forename: Evelin
authors.initials: E
authors.lastname: Schwarzer
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D015153:Blotting, Western; D004912:Erythrocytes / Q000469:parasitology; D005434:Flow Cytometry; D006801:Humans; D008288:Malaria; D008856:Microscopy, Fluorescence; D018384:Oxidative Stress / Q000187:drug effects; D010545:Peroxides / Q000494:pharmacology*; D047229:Plakortis; D010963:Plasmodium falciparum; D061065:Polyketides / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000962:Antimalarials; D010545:Peroxides; D061065:Polyketides; D017382:Reactive Oxygen Species
keywords: 4-hydroxynonenal; Antimalarial drug; Artemisinin resistance; Endoperoxide; Plakortin; Plasmodium falciparum; ROS