Gliotoxin induces caspase-dependent neurite degeneration and calpain-mediated general cytotoxicity in differentiated human neuroblastoma SH-SY5Y cells.
In this study, a significant increase by 50% in intracellular free calcium concentration ([Ca(2+)](i)) was observed in differentiated human neuroblastoma (SH-SY5Y) cells after exposure to 0.25microM of the fungal metabolite gliotoxin for 72h. Further, the involvement of caspases and calpains was demonstrated to underlie the gliotoxin-induced cytotoxic and neurite degenerative effects. The caspase inhibitor Z-VAD-fmk almost completely reduced the neurite degeneration from 40% degeneration of neurites to 5% as compared to control. Inhibition of calpains with calpeptin significantly attenuated gliotoxin-induced cytotoxicity, determined as reduction in total cellular protein content, from 43% to 14% as compared to control cells. Western blot analyses of alphaII-spectrin breakdown fragments confirmed activity of the proteases, and that alphaII-spectrin was cleaved by caspases in gliotoxin-exposed cells. These results show that calpains and caspases have a role in the toxicity of gliotoxin in differentiated SH-SY5Y cells and that the process may be Ca(2+)-mediated.
Axelsson
V
V
Department of Neurochemistry, The Arrhenius Laboratories for Natural Sciences, Stockholm University, Sweden. viktoria@neurochem.su.se
Holback
S
S
Sjögren
M
M
Gustafsson
H
H
Forsby
A
A
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002154:Calpain / Q000378:metabolism*; D020169:Caspases / Q000378:metabolism*; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005912:Gliotoxin / Q000494:pharmacology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D016501:Neurites / Q000378:metabolism*; D009447:Neuroblastoma / Q000378:metabolism*; D013049:Spectrin / Q000378:metabolism
D000590:Amino Acid Chloromethyl Ketones; D004791:Enzyme Inhibitors; D007166:Immunosuppressive Agents; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D013049:Spectrin; D005912:Gliotoxin; D002154:Calpain; D020169:Caspases; D002118:Calcium