title: Pathological and ultrastructural changes in cultured cells induced by venom from the ectoparasitic wasp Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae).
abstract: The ectoparasitic wasp Nasonia vitripennis produces a proteinaceous venom that induces death in fly hosts by non-paralytic mechanisms. Previous in vitro assays have suggested that the primary cause of cell and tissue death is oncosis, a non-programmed cell death (PCD) pathway characterized by cellular swelling and lysis. However, ultrastructural analyses of BTI-TN-5B1 cells exposed to LC(99) doses of wasp venom revealed cellular changes more consistent with apoptosis and/or non-apoptotic PCD than oncosis or necrosis: By 3h after incubation with venom, susceptible cells displayed indentations in the nuclear membranes, large nucleoli, and extensive vacuolization throughout the cytoplasm. In the vast majority of venom treated cells, annexin V bound to the plasma membrane surface within 15 min after treatment, a characteristic consistent with translocation of phosphatidylserine to the cell surface during the early stages of apoptosis. Likewise, mitochondrial transmembrane potential was depressed in cells within 15 min in venom-treated cells, an event that occurred in the absence of mitochondrial swelling or rupturing of cristae. Active caspase 3 was detected by fluorescent labeling in nearly all venom treated cells 3h after exposure to venom, and in turn, the potent caspase 3 inhibitor Z-VAD-FMK attenuated the morphological changes elicited by wasp venom and afforded protection to BTI-TN-5B1-4 cells.
authors.affiliation: Department of Biology, Loyola University Maryland, Baltimore, MD, USA. drivers@loyola.edu
authors.forename: David B
authors.initials: DB
authors.lastname: Rivers
authors.forename: Fevzi
authors.initials: F
authors.lastname: Uçkan
authors.forename: Ekrem
authors.initials: E
authors.lastname: Ergin
authors.forename: Donald A
authors.initials: DA
authors.lastname: Keefer
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D053148:Caspase 3 / Q000378:metabolism; D061945:Caspase Inhibitors; D016923:Cell Death / Q000502:physiology; D002460:Cell Line; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D006927:Hymenoptera / Q000737:chemistry / Q000378:metabolism*; D007915:Lepidoptera / Q000469:parasitology* / Q000648:ultrastructure; D053078:Membrane Potential, Mitochondrial / Q000502:physiology; D046529:Microscopy, Electron, Transmission; D014862:Wasp Venoms / Q000494:pharmacology*
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D014862:Wasp Venoms; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D053148:Caspase 3