Premium
NEW INSIGHT INTO THE SIGNALLING PATHWAYS OF HEAT STRESS‐INDUCED MYOCARDIAL PRECONDITIONING: PROTEIN KINASE Cε TRANSLOCATION AND HEAT SHOCK PROTEIN 27 PHOSPHORYLATION
Author(s) -
Arnaud Claire,
JoyeuxFaure Marie,
Bottari Serge,
GodinRibuot Diane,
Ribuot Christophe
Publication year - 2004
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.2004.03966.x
Subject(s) - protein kinase c , hsp27 , western blot , heat shock protein , p38 mitogen activated protein kinases , phosphorylation , cytosol , protein kinase a , kinase , gene isoform , hsp70 , microbiology and biotechnology , chemistry , biology , biochemistry , enzyme , gene
SUMMARY 1. Heat stress (HS) is known to induce delayed preconditioning against myocardial infarction 24 h later, but the exact signalling pathway of this response remains to be elucidated. In previous studies, we have shown evidence for the implication of protein kinase C (PKC) and p38 mitogen‐activated protein kinase (MAPK) in the HS‐induced reduction in infarct size. Furthermore, in their phosphorylated state, small heat shock proteins (Hsp27) seem to confer cytoskeletal protection. In the present study, we sought to determine the effect of HS on the subcellular distribution of PKC isoforms and on Hsp27 phosphorylation. 2. Rats were subjected to either HS (42°C for 15 min; HS group) or sham anaesthesia (sham group) before their hearts were excised. Myocardial tissue extracts obtained 20 min or 24 h after HS were processed for western blot analysis. 3. In the HS group, PKCε translocated from the cytosolic to the particulate fraction (4426 ± 128 vs 6258 ± 316 arbitrary units; P = 0.002). Chelerythrine (5 mg/kg, i.p.), a PKC inhibitor, abolished this translocation. Western blot analysis of Hsp27 24 h after HS showed a marked increase in protein expression and phosphorylation in the particulate fraction. 4. In the present study, we have shown that HS induces the translocation of PKCε from the cytosolic to the particulate fraction. Along with our previous observation that PKC is a trigger of HS‐induced myocardial preconditioning, the results of the present study suggest an important role of the ε isoform of PKC in this cardioprotective mechanism. Furthermore, we have also demonstrated that the cytoprotective protein Hsp27 is phosphorylated following HS. Therefore, we can conclude that PKC and MAPK/Hsp27 are involved in the signalling pathway of HS‐induced cardioprotection.