cardiovascular-agents and 20-hydroxy-5-8-11-14-eicosatetraenoic-acid

20-Hydroxyeicosatetraenoic acid (20-HETE) induces endothelial dysfunction and is correlated with diabetes. This study was designed to investigate the effects of 20-HETE on endothelial insulin signaling.Human umbilical vein endothelial cells (HUVECs) or C57BL/6J mice were treated with 20-HETE in the presence or absence of insulin, and p-ERK1/2, p-JNK, IRS-1/PI3K/AKT/eNOS pathway, were examined in endothelial cells and aortas by immunoblotting. eNOS activity and nitric oxide production were measured. 20-HETE increased ERK1/2 phosphorylation and IRS-1 phosphorylation at Ser616; these effects were reversed by ERK1/2 inhibition. We further observed that 20-HETE treatment resulted in impaired insulin-stimulated IRS-1 phosphorylation at Tyr632 and subsequent PI3-kinase/Akt activation. Furthermore, 20-HETE treatment blocked insulin-stimulated phosphorylation of eNOS at the stimulatory Ser1177 site, eNOS activation and NO production; these effects were reversed by inhibiting ERK1/2. Treatment of C57BL/6J mice with 20-HETE resulted in ERK1/2 activation and impaired insulin-dependent activation of the IRS-1/PI3K/Akt/eNOS pathway in the aorta. Our data suggest that the 20-HETE activation of IRS-1 phosphorylation at Ser616 is dependent on ERK1/2 and leads to impaired insulin-stimulated vasodilator effects that are mediated by the IRS-1/PI3K/AKT/eNOS pathway.

Topics: Animals; Aorta; Cardiovascular Agents; Cardiovascular Diseases; Cells, Cultured; Drug Evaluation, Preclinical; Extracellular Signal-Regulated MAP Kinases; Human Umbilical Vein Endothelial Cells; Humans; Hydroxyeicosatetraenoic Acids; Insulin; Insulin Receptor Substrate Proteins; MAP Kinase Signaling System; Mice, Inbred C57BL; Nitric Oxide; Nitric Oxide Synthase Type III; Phosphatidylinositol 3-Kinases; Phosphorylation; Protein Processing, Post-Translational; Proto-Oncogene Proteins c-akt; Serine

The present study evaluated the contribution of cytochrome P-450 omega-hydroxylase in modulating the reactivity of cremaster muscle arterioles in normotensive rats on high-salt (HS) and low-salt (LS) diet and in rats with reduced renal mass hypertension (RRM-HT). Changes in arteriolar diameter in response to ACh, sodium nitroprusside (SNP), ANG II, and elevated O(2) were measured via television microscopy under control conditions and following cytochrome P-450 omega-hydroxylase inhibition with 17-octadecynoic acid (17-ODYA) or N-methylsulfonyl-12,12-dibromododec-11-enamide (DDMS). In normotensive rats on either LS or HS diet, resting tone was unaffected and arteriolar reactivity to ACh or SNP was minimally affected by cytochrome P-450 omega-hydroxylase inhibition. In RRM-HT rats, cytochrome P-450 omega-hydroxylase inhibition reduced resting tone and significantly enhanced arteriolar dilation to ACh and SNP. Treatment with 17-ODYA or DDMS inhibited arteriolar constriction to ANG II and O(2) in all the groups, although the degree of inhibition was greater in RRM-HT than in normotensive animals. These results suggest that metabolites of cytochrome P-450 omega-hydroxylase contribute to the altered reactivity of skeletal muscle arterioles to vasoconstrictor and vasodilator stimuli in RRM-HT.

Topics: Acetylcholine; Amides; Angiotensin II; Animals; Arterioles; Blood Pressure; Cardiovascular Agents; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Enzyme Inhibitors; Fatty Acids, Unsaturated; Hydroxyeicosatetraenoic Acids; Hypertension, Renal; Male; Microscopy, Video; Mixed Function Oxygenases; Muscle, Skeletal; Nitroprusside; Oxygen; Perfusion; Rats; Rats, Sprague-Dawley; Sodium Chloride, Dietary; Sulfones