Chelerythrine rapidly induces apoptosis through generation of reactive oxygen species in cardiac myocytes.
The role of protein kinase C (PKC) inhibition in cardiac myocyte apoptosis has not been well understood. We investigated the mechanism, by which chelerythrine, a commonly used PKC inhibitor, induces potent myocyte death. Chelerythrine (6-30 microm) rapidly induced pyknosis, shrinkage and subsequent cell death in cardiac myocytes. Chelerythrine-induced myocyte death was accompanied by nuclear fragmentation and activation of caspase-3 and -9, while it was prevented by XIAP, suggesting that the cell death is due to apoptosis. Higher concentrations of chelerythrine caused necrotic cell death where neither cell shrinkage nor caspase activation was observed. Intravenous injection of chelerythrine (5 mg/kg) also increased apoptosis in adult rat hearts in vivo. Downregulation of the phorbol 12-myristate 13-acetate (PMA)-sensitive PKC failed to affect chelerythrine-induced apoptosis, while anti-oxidants, including N-acetyl-L-cysteine (NAC) and glutathione, inhibited it, suggesting that generation of reactive oxygen species (ROS) rather than inhibition of PMA-sensitive PKC mediates chelerythrine-induced cardiac myocyte apoptosis. Chelerythrine caused cytochrome c release from mitochondria, which was significantly inhibited in the presence of NAC, suggesting that ROS mediates chelerythrine-induced cytochrome c release. Partial inhibition of cytochrome c release by Bcl-X(L) significantly reduced chelerythrine-induced apoptosis. These results suggest that chelerythrine rapidly induces cardiac myocyte apoptosis and that production of ROS, possibly H(2)O(2), and subsequent cytochrome c release from mitochondria play an important role in mediating chelerythrine-induced rapid cardiac myocyte apoptosis.
Yamamoto
S
S
Cardiovascular Research Institute, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark 07103, USA.
Seta
K
K
Morisco
C
C
Vatner
S F
SF
Sadoshima
J
J
D000111:Acetylcysteine / Q000494:pharmacology; D000256:Adenoviridae / Q000235:genetics; D000470:Alkaloids; D000818:Animals; D000831:Animals, Newborn; D017304:Annexin A5 / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis; D053119:Benzophenanthridines; D020169:Caspases / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D053938:DNA Fragmentation; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D005822:Genetic Vectors; D005978:Glutathione / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D015151:Immunoblotting; D020287:In Situ Nick-End Labeling; D007275:Injections, Intravenous; D008856:Microscopy, Fluorescence; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism; D009336:Necrosis; D010617:Phenanthridines / Q000494:pharmacology*; D020033:Protein Isoforms; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species; D019311:Staurosporine / Q000494:pharmacology; D013347:Subcellular Fractions; D013755:Tetradecanoylphorbol Acetate; D013997:Time Factors
D000470:Alkaloids; D017304:Annexin A5; D000975:Antioxidants; D053119:Benzophenanthridines; D004791:Enzyme Inhibitors; D010617:Phenanthridines; D020033:Protein Isoforms; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; C016299:chelerythrine; D011493:Protein Kinase C; D020169:Caspases; D005978:Glutathione; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate; D000111:Acetylcysteine