Oxidative stress stimulates multiple MAPK signalling pathways and phosphorylation of the small HSP27 in the perfused amphibian heart

Abstract

SUMMARYWe investigated the activation of three subfamilies of MAPKs (ERK, JNKs and p38-MAPK) by oxidative stress in the isolated perfused amphibian heart. Activation of p43-ERK by 100 μmol l-1 H2O2was maximally observed within 5 min, remained elevated for 30 min and was comparable with the effect of 1 μmol l-1 PMA. p43-ERK activation by H2O2 was inhibited by PD98059 but not by SB203580. The p46 and p52 species of JNKs were maximally activated by 2.5- and 2.1-fold,respectively, by 100 μmol l-1 H2O2 within 2 min. JNK activation was still detectable after 15 min, reaching control values at 30 min of treatment. p38-MAPK was maximally activated by 9.75-fold by 100 μmol l-1 H2O2 after 2 min and this activation progressively declined thereafter, reaching control values within 45 min of treatment. The observed dose-dependent profile of p38-MAPK activation by H2O2 revealed that 30 μmol l-1 H2O2 induced maximal phosphorylation,whereas 100–300 μmol l-1 H2O2induced considerable activation of the kinase. Our studies also showed that the phosphorylation of MAPKAPK2 by H2O2 followed a parallel time-dependent pattern and that SB203580 abolished this phosphorylation. Furthermore, our experiments clearly showed that 30 μmol l-1 H2O2 induced a strong, specific phosphorylation of HSP27. Our immunohistochemical studies showed that immune complexes of phosphorylated forms of both p38-MAPK and HSP27 were strongly enhanced by 30 μmol l-1 H2O2 in the perinuclear region as well as dispersedly in the cytoplasm of ventricular cells and that SB203580 abolished this phosphorylation. These data indicate that oxidative stress is a powerful activator of all three MAPK subfamilies in the amphibian heart. Stimulation of p38-MAPK and the consequent phosphorylation of HSP27 may be important in cardioprotection under such conditions.

Artemisinin mimics calorie restriction to extend yeast lifespan via a dual-phase mode: a conclusion drawn from global transcriptome profiling

“…During this process, Sod1 and Sod2 are induced in ME yeast cells, whereas Cta2 and Gpx1 are otherwise induced in PME yeast cells. Also, it is noteworthy that ROS is a powerful activator of all MAPK subfamilies (ERK, JNKs and p38-MAPK) [38]. Indeed, we did not observe the upregulation of Sod1, Sod2, and other antioxidant genes that generate H 2 O 2 except for Cta2 and Gpx1 that degrade H 2 O 2 in PME yeast cells, suggesting an extremely low ROS level due to an active antioxidative response.…”

Extracellular pH changes activate the p38-MAPK signalling pathway in the amphibian heart

“…p38-MAPK is activated by dual phosphorylation at the Thr and Tyr residues of the Thr-GlyTyr motif which lies at the activation loop of the molecule (Davis, 1994). The p38-MAPK activation can be induced by cytokines (Freshney et al, 1994;Goedert et al, 1997), or oxidative (Clerk et al, 1998;Gaitanaki et al, 2003) and mechanical (Aggeli et al, 2001b;Aikawa et al, 2001) stresses.…”

K Ca 3.1 upregulation preserves endothelium‐dependent vasorelaxation during aging and oxidative stress

“…Studies have shown that H 2 O 2 enhances the tyrosine phosphorylation of Src kinases and mitogen‐activated protein kinases, leading to activation of gene expression, including activator protein‐1 (Hardwick & Sefton, 1997; Jaramillo & Olivier, 2002; Gaitanaki et al ., 2003). Consistent with these results, H 2 O 2 increased the phosphorylation of the Src family kinase Fyn.…”