This study examined the effects of major
burn injury on the cellular distribution of several PKC
isoforms in adult rat hearts and examined the hypothesis that PKC plays a regulatory role in cardiomyocyte
cytokine secretion.
Burn trauma was given over 40% total body surface area in Sprague-Dawley rats. An in vitro model of
burn injury included addition of
burn serum, 10% by volume, to primary cardiomyocyte cultures (
collagen perfusion). In vivo
burn injury produced redistribution of PKCdelta, PKCepsilon, and PKCalpha from the cytosol (soluble) to the membrane (particulate) component of the myocardium. This activation of the PKC
isoforms was evident 2 h after
burn injury and progressively increased over 24 h postburn. Addition of
burn serum to isolated myocytes produced similar PKC
isoform redistribution from the soluble to the particulate compartment, promoted myocyte Ca2+ and Na+ loading, and promoted robust myocyte secretion of inflammatory
cytokines similar to that reported after in vivo
burn injury. Pretreating cardiomyocytes with either
calphostin or PKCepsilon inhibitory
peptide, a potent inhibitor of PKCepsilon, prevented
burn serum-related redistribution of the PKCepsilon
isoform and prevented
burn serum-related cardiomyocyte secretion of
TNF-alpha, IL-1beta,
IL-6, and
IL-10. These data suggest that the PKCepsilon
isoform plays a pivotal role in myocardial inflammatory response to injury, altering cardiac function by modulating cardiomyocyte inflammatory
cytokine response to injury.