Abstract
Hearts isolated from whole body-heated animals have a better recovery than unheated control after an ischemia/reperfusion challenge. This effect has been attributed to the heat-induced increase in the inducible form of HSP70. Recently, we found that the cognate form of HSP70 (HSC70) also accumulated after thermal pretreatment. Furthermore, there was a redistribution of the HSC70 protein to the nuclear compartment, which coincided with the development of oxidative resistance. Here we assessed the protective function of HSC70 by examining whether its overexpression protects against a reperfusion-simulated oxidative insult. Rat HSC70 cDNA had been inserted to an eukaryotic expression vector, pRC/CMV. In the resultant construct, pCMV-HSC70, transcription of the HSC70 cDNA is driven by the strong cytomegaloviral promoter. This plasmid was then introduced into the heart-derived H9c2 myocytes, and the cells permanently transfected with pCMV-HSC70 were selected with G418. Immunoblot analysis indicated that some of the G418-resistant clones expressed the HSC70 protein at least two-fold higher than either untransfected or pRC/CMVtransfected cells. When subjected to a xanthine oxidase-catalyzed oxygen radical generating system, these clones were found to survive better than untransfected or pRC/CMV-transfected cells. These results, demonstrating an antioxidant effect of HSC70, suggest that HSC70 may be an important molecule to preserve the myocardium during reperfusion following ischemia.
Original language | English |
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Pages (from-to) | A1295 |
Journal | FASEB Journal |
Volume | 10 |
Issue number | 6 |
State | Published - 1996 |
Externally published | Yes |