Nongenomic activation of the GC-A enzyme by resveratrol and estradiol downstream from membrane estrogen receptors in human coronary arterial cells

Background and aimResveratrol (RSVL), a polyphenolic phytoestrogen in grapes, confers multifaceted cardiovascular benefits. The cellular and molecular basis of RSVL actions has been largely undefined until now.Methods and resultsIn human coronary smooth muscle cells (HCSMCs), RSVL markedly (3.2-fold) enhanced cGMP formation (t1/2: 6.3 min, EC50: 1.8 μM) and stimulated kinase-G activity (4-fold). By contrast, RSVL had no effect on cAMP or PKA activity in these cells. The RSVL-enhanced cGMP/kinase-G activity was not abrogated by the nitric oxide synthase-inhibitor (L-NMMA, 10 μM), or the soluble guanylyl cyclase (sGC)-inhibitor (ODQ, 10 μM). In membrane preparations from HCSMCs, RSVL activated GC in the particulate-, but not in the soluble-membrane fraction. Similar effects were due to the specific particulate-GC-A agonist atrial natriuretic peptide (ANP, 0.1–1 μM). The combined effects of RSVL and ANP were competitive. By contrast, the selective GC-B agonist (BNP) showed no response on cGMP, whereas that for GC-C (guanylin) produced only slight increases in cGMP levels. Estradiol (E2) mimicked the effects of RSVL on cGMP, but showed a 46% lower maximal response. Combining E2 with RSVL showed a competitive, rather than an additive, response. Further, cGMP formation by RSVL or E2 was significantly attenuated by the pure estrogen receptor blocker, ICI-182,780 (10 μM).ConclusionThese findings are the first to link RSVL with pGC/kinase-G activation downstream from membrane ERs in the vasculature, thus substantiating its coronary protective effects, even in endothelium-disrupted coronary arteries.