S- Enantiomer of 19-Hydroxyeicosatetraenoic Acid Preferentially Protects Against Angiotensin II-Induced Cardiac Hypertrophy.

We had recently demonstrated that the racemic mixture of 19-hydroxyeicosatetraenoic acid (19-HETE) protects against angiotensin II (Ang II)-induced cardiac hypertrophy. Therefore, the purpose of this study was to investigate whether the R- or S- enantiomer of 19-HETE confers cardioprotection against Ang II-induced cellular hypertrophy in RL-14 and H9c2 cells. Both cell lines were treated with vehicle or 10 μ M Ang II in the absence and presence of 20 μ M 19( R ) - HETE or 19( S ) - HETE for 24 hours. Thereafter, the level of midchain HETEs was determined using liquid chromatography-mass spectrometry. Gene- and protein-expression levels were measured using real-time polymerase chain reaction and Western blot analysis, respectively. The results showed that both 19( R ) - HETE and 19( S ) - HETE significantly decreased the metabolite formation rate of midchain HETEs, namely 8-, 9-, 12-, and 15-HETE, compared with control group, whereas the level of 5-HETE was selectively decreased by S- enantiomer. Moreover, both 19( R ) - HETE and 19( S ) - HETE significantly inhibited the catalytic activity of CYP1B1 and decreased the protein expression of 5- and 12-lipoxygenase (LOX) as well as cyclo-oxygenase-2 (COX-2). Notably, the decrease in 15-LOX protein expression was only mediated by 19( S ) - HETE. Interestingly, both enantiomers protected against Ang II-induced cellular hypertrophy, as evidenced by a significant decrease in mRNA expression of β / α -myosin heavy chain ratio, atrial natriuretic peptide, and interleukins 6 and 8. Our data demonstrated that S- enantiomer of 19-HETE preferentially protected against Ang II-induced cellular hypertrophy by decreasing the level of midchain HETEs, inhibiting catalytic activity of CYP1B1, decreasing protein expression of LOX and COX-2 enzymes, and decreasing mRNA expression of IL-6 and IL-8.