Gomisin A induces Ca2+-dependent activation of eNOS in human coronary artery endothelial cells.
OBJECTIVE
Gomisin A (GA) is a small molecular weight lignan contained in Fructus Schisandrae, the dried seed of Schisandra chinensis which is widely used as a tonic in traditional Korean medicine. We previously demonstrated that GA induces endothelium-dependent and -independent relaxation in rat thoracic aorta, however the signaling pathways involved was not clarified. In this study, we examined whether GA could actually induce nitric oxide (NO) production and clarified the mechanism in cultured human coronary artery endothelial cells (HCAEC).


RESULTS
Treatment of HCAEC with GA induced NO production in a time- and concentration-dependent manner in association with an enhanced endothelial NO synthase (eNOS) activity with an increased cytosolic translocation of eNOS. Both GA-induced NO production and eNOS activation were attenuated by pretreatment of the cells with EGTA, an extracellular Ca(2+) chelator, and BAPTA-AM, an intracellular Ca(2+) chelator, but not by LY 294002, a PI3-kinase/Akt inhibitor, suggesting involvement of Ca(2+). Furthermore, GA rapidly increased the intracellular Ca(2+) concentration, which was abolished in Ca(2+) free media.


CONCLUSIONS
Taken together, our results suggest that GA induces Ca(2+)-dependent activation and translocation of eNOS in HCAEC, events linked to NO production and thereby endothelial-dependent vasorelaxation.
Park
Ji Young
JY
Department of Pharmacology, School of Medicine, and MRC for Ischemic Tissue Regeneration and Medical Research Institute, Pusan National University, Yangsan, Gyeongnam 626-770, Republic of Korea.
Shin
Hwa Kyoung
HK
Choi
Young Whan
YW
Lee
You Jin
YJ
Bae
Sun Sik
SS
Han
Jin
J
Kim
Chi Dae
CD
D002118:Calcium / Q000097:blood; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D002867:Chromones / Q000494:pharmacology; D003331:Coronary Vessels; D034242:Cyclooctanes / Q000302:isolation & purification / Q000494:pharmacology*; D004149:Dioxoles / Q000302:isolation & purification / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects* / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005638:Fruit; D006801:Humans; D017705:Lignans / Q000302:isolation & purification / Q000494:pharmacology*; D009025:Morpholines / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis*; D052250:Nitric Oxide Synthase Type III / Q000097:blood*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D032141:Schisandra / Q000737:chemistry*; D013997:Time Factors; D014665:Vasodilator Agents / Q000302:isolation & purification / Q000494:pharmacology*
D002614:Chelating Agents; D002867:Chromones; D034242:Cyclooctanes; D004149:Dioxoles; D004791:Enzyme Inhibitors; D017705:Lignans; D009025:Morpholines; D010936:Plant Extracts; D014665:Vasodilator Agents; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D009569:Nitric Oxide; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D004533:Egtazic Acid; C033585:schizandrol B; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; D002118:Calcium