Affiliation:
1. From the Departments of Medicine (Cardiology) and Cell Biology (S.B., S.M., A.L.W., R.N.K.), Albert Einstein College of Medicine, Bronx, NY; Division of Endocrinology (V.L.C., A.D.), Northwestern University Medical Center, Chicago, Ill; and Idun Pharmaceuticals (A.S.), La Jolla, Calif. S.B.’s present address is Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
Abstract
Abstract
—Many cell types undergo apoptosis under conditions of ischemia. Little is known, however, about the molecular pathways that mediate this response. A cellular and biochemical approach to elucidate such signaling pathways was undertaken in primary cultures of cardiac myocytes, a cell type that is especially sensitive to ischemia-induced apoptosis. Deprivation of serum and glucose, components of ischemia in vivo, resulted in myocyte apoptosis, as determined by nuclear fragmentation, internucleosomal cleavage of DNA, and processing of caspase substrates. These manifestations of apoptosis were blocked by zVAD-fmk, a peptide caspase inhibitor, indicating that caspase activity is necessary for the progression of apoptosis in this model. In contrast to control cells, apoptotic myocytes exhibited cytoplasmic accumulation of cytochrome
c
, indicating release from the mitochondria. Furthermore, both caspase-9 and caspase-3 were processed to their active forms in serum-/glucose-deprived myocytes. Caspase processing, but not cytochrome
c
release, was inhibited by zVAD-fmk, placing the latter event upstream of caspase activation. This evidence demonstrates that components of ischemia activate the mitochondrial death pathway in cardiac myocytes.
Publisher
Ovid Technologies (Wolters Kluwer Health)
Subject
Cardiology and Cardiovascular Medicine,Physiology
Cited by
241 articles.
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