title: Differential activation of MAPKs by individual and combined ochratoxin A and citrinin treatments in porcine kidney PK15 cells.
abstract: The aim of this study was to investigate the underlying mechanisms of OTA and CTN individual and combined toxicity in porcine kidney PK15 cells of proximal tubule origin. Activation and expression of mitogen-activated protein kinases (MAPKs) ERK, JNK and p38 were determined by Western blot analysis. MAPKs were differentially activated by single or dual OTA and CTN treatments. Single OTA and CTN stimulated transient ERK and prolonged JNK activation, while phospho-p38 signal was more persistent after OTA treatment. Mycotoxin mixture provoked significant down-regulation of ERK activation, more prolonged phospho-p38 signal, and two-stage JNK phosphorylation pattern. In order to define the role of particular MAPKs in mycotoxin(s) cytotoxicity, we performed MTT assay with specific MAPKs inhibitors. In both individual and combined treatments JNK and p38 inhibition significantly induced cell survival. When cells were exposed to toxin mixture, inhibition of ERK also promoted cell survival, although to a lesser extent that JNK and p38 inhibition. Next we investigated the association between calcium (Ca(2+)) and MAPKs after OTA and/or CTN treatments, and we employed Ca(2+) chelator BAPTA-AM. We demonstrated that p38 activation was significantly down-regulated in cells treated with CTN alone or OTA + CTN suggesting the role of Ca(2+) in mycotoxin-induced cell death.
authors.affiliation: Department of Medical Biochemistry and Hematology, Faculty of Pharmacy and Biochemistry, University of Zagreb, Zagreb, Croatia.
authors.forename: Lada
authors.initials: L
authors.lastname: Rumora
authors.affiliation: Department of Pharmaceutical Botany, Faculty of Pharmacy and Biochemistry, University of Zagreb, Zagreb, Croatia.
authors.forename: Ana-Marija
authors.initials: AM
authors.lastname: Domijan
authors.affiliation: Department of Medical Biochemistry and Hematology, Faculty of Pharmacy and Biochemistry, University of Zagreb, Zagreb, Croatia.
authors.forename: Tihana
authors.initials: T
authors.lastname: Zanić Grubišić
authors.affiliation: Department of Microbiology, Faculty of Pharmacy and Biochemistry, University of Zagreb, Zagreb, Croatia. Electronic address: msegvic@pharma.hr.
authors.forename: Maja
authors.initials: M
authors.lastname: Segvić Klarić
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival; D002953:Citrinin / Q000494:pharmacology*; D004789:Enzyme Activation; D007668:Kidney / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009793:Ochratoxins / Q000494:pharmacology*; D013552:Swine
chemical_list: D009793:Ochratoxins; C025589:ochratoxin A; D002953:Citrinin; D020928:Mitogen-Activated Protein Kinases; D002118:Calcium
keywords: Calcium; Citrinin; Kidney; MAPK; Ochratoxin A; PK15 cells