Abstract 331: 20-hydroxyeicosatetraenoic Acid is Involved in Angiotensin II-mediated Apoptosis in Rat Cardiac Myocyte
Cardiomyocyte apoptosis has been documented involved in a variety of cardiac stresses, including ischemia-reperfusion injury, heart failure, and cardiomyopathy. Both angiotensin II (Ang II) and 20-Hydroxyeicosatetraenoic Acid (20-HETE), a hydroxylation product of arachidonic acid catalyzed by CYP450-ω hydroxylase, induce apoptosis in cardiomyocyte. However, the crosstalk between 20-HETE and Ang II in cardiomyocytes apoptosis process is unclear. In the current study, we examined apoptosis using flow cytometry in primary cultured neonatal rat ventricular myocytes treated with control, Ang II (100nM), Ang II plus HET0016 (10μM), HET0016, or 20-HETE (10nM) along. The results demonstrated that treatment with Ang II or 20-HETE significantly increased apoptosis and that Ang II-induced apoptosis were markedly attenuated by HET0016, a 20-HETE agonist. In addition, Ang II-induced increases of caspase-3 activity were significantly attenuated by 20.9±3.4% after co-treatment with HET0016. Our results also demonstrated that HET0016 significantly suppressed Ang II-induced increases of superoxide production by 27.52.3% and mitochondrial membrane potential by 64.5±6.3%. Finally, Ang II-induced nuclei crenation, chromatin condensation and fractionation were attenuated by 73.6±8.5% with HET0016 pre-treatment. In addition, treatment cardiomyocytes with Ang II increased CYP4A1 expression and 20-HETE production, measured by Western blot, real-time RT-PCR, and mass spectrometric analysis. All results suggest that 20-HETE may play a key role in Ang II-induced apoptosis in cardiomyocytes. 20-HETE and 20-HETE-producing enzymes could be novel targets for the treatment of Ang II related cardiac diseases.
- © 2012 by American Heart Association, Inc.