Resveratrol activates the kinase-G system in human coronary smooth muscle cells via a nongenomic, estrogen-independant mechanism

ABSTRACT

Resveratrol [RSVL], a polyphenolic phytoestrogen in grapes, confers multifaceted cardiovascular benefits. The cellular and molecular basis of RSVL actions has been largely undefined. Currently, in human coronary smooth muscle cells [HCSMCs], RSVL markedly [3.2 fold] enhanced cGMP formation [t1/2 6.3 min, EC 50 1.8 microM] 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 either of the phosphodiesterase-inhibitors [zaprinast, 10 microM, IBMX, 0.5mM], the nitric oxide synthase-inhibitor [L-NMMA, 10 microM], or the soluble guanylyl cyclase [sGC]-inhibitor [ODQ, 10 microM].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 [pGC] agonist atrial natriuretic peptide [ANP, 0.1-1 microM]. By contrast, the nitric oxide donor, SNAP [1-10 microM] stimulated GC only in the soluble fraction. Responses to RSVL were insensitive to the estrogen receptor blockers, tamoxifen and ICI-182,780. Conversely, pretreatment with the PKC activator, PMA [0.1 microM], a known desensitizer of pGC, markedly blunted the RSVL-enhanced GC-activity. These findings demonstrate that RSVL triggers a pGC-mediated stimulation of protein kinase-G in human coronary smooth muscle cells. This pathway appears to be independent of the conventional estrogen machinery and supports both vasodilatory and anti-atherogenic actions for RSVL