title: The marine toxin palytoxin induces necrotic death in HaCaT cells through a rapid mitochondrial damage.
abstract: Palytoxin (PLTX) is one of the most toxic algal biotoxin known so far. It transforms the Na(+)/K(+)-ATPase into a cationic channel inducing a massive intracellular Na(+) influx. However, from a mechanistic point of view, the features and the intracellular pathways leading to PLTX-induced cell death are still not completely characterized. This study on skin HaCaT keratinocytes demonstrates that PLTX induces necrosis since propidium iodide uptake was observed already after 1 h toxin exposure, an effect that was not lowered by toxin removal. Furthermore, necrotic-like morphological alterations were evidenced by confocal microscopy. Apoptosis occurrence was excluded since no caspases 3/7, caspase 8, and caspase 9 activation as well as no apoptotic bodies formation were recorded. Necrosis was preceded by a very early mitochondrial damage as indicated by JC-1 fluorescence shift, recorded already after 5 min toxin exposure. This shift was totally abolished when Na(+) and Ca(2+) ions were withdrawn from culture medium, whereas cyclosporine-A was ineffective, excluding the occurrence of a controlled biochemical response. These results clearly establish necrosis as the primary mechanism for PLTX-induced cell death in HaCaT cells. The rapidity of mitochondrial damage and the consequent irreversible necrosis rise serious concerns about the very fast onset of PLTX toxic effects.
authors: Department of Life Science, University of Trieste, Via Valerio 6, 34127 Trieste, Italy. Electronic address: marco.pelin@hotmail.it.
authors: Marco
authors: M
authors: Pelin
authors: Department of Life Science, University of Trieste, Via Valerio 6, 34127 Trieste, Italy. Electronic address: silvio.sosa@econ.units.it.
authors: Silvio
authors: S
authors: Sosa
authors: Department of Life Science, University of Trieste, Via Valerio 6, 34127 Trieste, Italy. Electronic address: pacorsab@units.it.
authors: Sabrina
authors: S
authors: Pacor
authors: Department of Life Science, University of Trieste, Via Valerio 6, 34127 Trieste, Italy. Electronic address: tubaro@units.it.
authors: Aurelia
authors: A
authors: Tubaro
authors: Department of Life Science, University of Trieste, Via Valerio 6, 34127 Trieste, Italy. Electronic address: florioc@units.it.
authors: Chiara
authors: C
authors: Florio
mesh_terms: D000178:Acrylamides / Q000494:pharmacology*; D015153:Blotting, Western; D020169:Caspases / Q000187:drug effects / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003064:Cnidarian Venoms / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects*; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000187:drug effects*; D000095702:Polyether Toxins
chemical_list: D000178:Acrylamides; D020169:Caspases; D003064:Cnidarian Venoms; C010272:palytoxin; D000095702:Polyether Toxins
keywords: Apoptosis; HaCaT cells; Mitochondria; Necrosis; Palytoxin