The paralytic shellfish toxin, saxitoxin, enters the cytoplasm and induces apoptosis of oyster immune cells through a caspase-dependent pathway

Type Article
Date 2017-09
Language English
Author(s) Abikhalil Celina1, Finkelstein Darren S.2, Conejero Genevieve3, 4, Du Bois Justin2, Destoumieux-Garzon Delphine1, Rolland Jean-Luc1
Affiliation(s) 1 : Univ Montpellier, IFREMER, CNRS, IHPE,UMR 5244,Univ Perpignan, Via Domitia, F-34095 Montpellier, France.
2 : Stanford Univ, Dept Chem, 333 Campus Dr, Stanford, CA 94305 USA.
3 : UMR B, Plant Cell Imaging Platform PHIV, Montpellier, France.
4 : UM, PMP, INRA, CNRS,SupAgro, Montpellier, France.
Source Aquatic Toxicology (0166-445X) (Elsevier Science Bv), 2017-09 , Vol. 190 , P. 133-141
DOI 10.1016/j.aquatox.2017.07.001
WOS© Times Cited 21
Keyword(s) Shellfish, Toxin, Harmful algae, Phytoplankton
Abstract

Exposure of the toxin-producing dinoflagellate Alexandrium catenella (A. catenella) was previously demonstrated to cause apoptosis of hemocytes in the oyster species Crassostrea gigas. In this work, a coumarin-labeled saxitoxin appeared to spread throughout the cytoplasm of the hemocytes. PSTs, including saxitoxin, were also shown to be directly responsible for inducing apoptosis in hemocytes, a process dependent on caspase activation and independent of reactive oxygen species (ROS) production. A series of in vitro labeling and microscopy experiments revealed that STX and analogs there of induced nuclear condensation, phosphatidylserine exposure, membrane permeability, and DNA fragmentation of hemocytes. Unlike in vertebrates, gonyautoxin-5 (GTX5), which is present in high concentrations in A. catenella, was found to be more toxic than saxitoxin (STX) to oyster immune cells. Altogether, results show that PSTs produced by toxic dinoflagellates enter the cytoplasm and induce apoptosis of oyster immune cells through a caspase-dependent pathway. Because of the central role of hemocytes in mollusc immune defense, PST-induced death of hemocytes could negatively affect resistance of bivalve molluscs to microbial infection.

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Abikhalil Celina, Finkelstein Darren S., Conejero Genevieve, Du Bois Justin, Destoumieux-Garzon Delphine, Rolland Jean-Luc (2017). The paralytic shellfish toxin, saxitoxin, enters the cytoplasm and induces apoptosis of oyster immune cells through a caspase-dependent pathway. Aquatic Toxicology, 190, 133-141. Publisher's official version : https://doi.org/10.1016/j.aquatox.2017.07.001 , Open Access version : https://archimer.ifremer.fr/doc/00391/50272/