The c-Jun-N-terminal kinase is involved in the neurotoxic effect of azaspiracid-1.
OBJECTIVE
Azaspiracids (AZAs) are marine phycotoxins with an unknown mechanism of action, recently implicated in human intoxications. The predominant analog in nature, AZA-1 targets several organs in vivo, including the central nervous system and exhibits high neurotoxicity in vitro.


METHODS
We used pharmacological tools to inhibit the cytotoxic effect of the toxin in primary cultured neurons. Immunocytochemical techniques in combination with confocal microscopy were employed to examine the cellular mechanisms involved in the neurotoxic effect of AZA-1.


RESULTS
Several targets for azaspiracid-induced neurotoxicity, specifically the cAMP pathway, or protein kinase C and phosphatidylinositol 3-kinase activation were excluded. Interestingly, the specific c-Jun-N-terminal protein kinase (JNK) inhibitor SP 600125 protected cultured neurons against AZA-induced cytotoxicity. Immunocytochemistry experiments showed that AZA-1 increased the amount of phosphorylated JNK and caused nuclear translocation of the active protein that was prevented by SP 600125.


CONCLUSIONS
Our data constitute the relationship between azaspiracid-induced cytotoxicity and specific modifications in cellular transduction signals, specifically we found that JNK activation is associated with the cytotoxic effect of the toxin. These results should provide the basis to identify the mechanism of action of this group of toxins.
Vale
Carmen
C
Departamento de Farmacología, Facultad de Veterinaria, USC, Lugo, Spain.
Gómez-Limia
Belén
B
Nicolaou
K C
KC
Frederick
Michael O
MO
Vieytes
Mercedes R
MR
Botana
Luis M
LM
D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects; D002467:Cell Nucleus / Q000187:drug effects / Q000201:enzymology; D002478:Cells, Cultured; D002531:Cerebellum / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D000242:Cyclic AMP / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008387:Marine Toxins / Q000633:toxicity*; D051379:Mice; D009474:Neurons / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D009498:Neurotoxins / Q000633:toxicity*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D013141:Spiro Compounds / Q000633:toxicity*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D000095702:Polyether Toxins
D000873:Anthracenes; D000242:Cyclic AMP; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D008387:Marine Toxins; D009498:Neurotoxins; D010750:Phosphoproteins; D011493:Protein Kinase C; D017382:Reactive Oxygen Species; D013141:Spiro Compounds; D048051:p38 Mitogen-Activated Protein Kinases; C406592:azaspiracid; D000095702:Polyether Toxins; C432165:pyrazolanthrone