Angiotensin II induces apoptosis of adult ventricular myocytes in vitro

To determine whether angiotensin II (Ang II) activates the suicide program of myocytes, primary cultures of adult rat ventricular myocytes were exposed to 10(-9) M of Ang II, for 24 h. Ang II resulted in a five-fold increase in programmed myocyte cell death (PMCD) documented by the terminal deoxynuc...

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Bibliographic Details
Published in:Journal of molecular and cellular cardiology 1997-03, Vol.29 (3), p.859-870
Main Authors: Kajstura, J, Cigola, E, Malhotra, A, Li, P, Cheng, W, Meggs, L G, Anversa, P
Format: Article
Language:English
Subjects:
Alkaloids
Angiotensin II - pharmacology
Angiotensin Receptor Antagonists
Animals
Apoptosis - drug effects
Benzophenanthridines
Biphenyl Compounds - pharmacology
Calcimycin - pharmacology
Calcium - metabolism
Cells, Cultured
Chelating Agents - pharmacology
Cytosol - metabolism
Egtazic Acid - analogs & derivatives
Egtazic Acid - pharmacology
Enzyme Inhibitors - pharmacology
Imidazoles - pharmacology
Ionophores - pharmacology
Isoenzymes - metabolism
Losartan
Myocardium - cytology
Phenanthridines - pharmacology
Protein Kinase C - antagonists & inhibitors
Protein Kinase C - metabolism
Protein Kinase C-delta
Protein Kinase C-epsilon
Pyridines - pharmacology
Rats
Rats, Sprague-Dawley
Receptor, Angiotensin, Type 1
Receptor, Angiotensin, Type 2
Tetrazoles - pharmacology
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Summary:To determine whether angiotensin II (Ang II) activates the suicide program of myocytes, primary cultures of adult rat ventricular myocytes were exposed to 10(-9) M of Ang II, for 24 h. Ang II resulted in a five-fold increase in programmed myocyte cell death (PMCD) documented by the terminal deoxynucleotidyl transferase assay and confirmed by DNA agarose gel electrophoresis. Ang II stimulation was associated with translocation of the epsilon and delta isoforms of protein kinase C (PKC) which was coupled with an increase in cytosolic Ca2+ in the cells. The PKC inhibitor chelerythrine abolished Ang II-mediated increases in cytosolic Ca2+ and PMCD. Similarly, pretreatment of cells with the intracellular Ca2+ chelator BAPTA/AM inhibited the formation of DNA strand breaks. Conversely, the Ca2+ ionophore A23187 markedly increased PMCD. Finally, the AT1 receptor antagonist, losartan, completely blocked Ang II-induced PMCD, whereas the AT2 receptor antagonist, PD123319, did not attenuate this phenomenon. In conclusion, ligand binding of AT1 receptors on myocytes triggers PMCD by a mechanism involving PKC-mediated increases in cytosolic calcium, which result in internucleosomal DNA fragmentation.
ISSN:0022-2828
DOI:10.1006/jmcc.1996.0333