Inhibitory Effects of Cytosolic Ca²⁺Concentration by Ginsenoside Ro Are Dependent on Phosphorylation of IP₃RI and Dephosphorylation of ERK in Human Platelets

Abstract

Intracellular Ca2+ ([Ca2+]i) is platelet aggregation-inducing molecule and is involved in activation of aggregation associated molecules. This study was carried out to understand the Ca2+-antagonistic effect of ginsenoside Ro (G-Ro), an oleanane-type saponin in Panax ginseng. G-Ro, without affecting leakage of lactate dehydrogenase, dose-dependently inhibited thrombin-induced platelet aggregation, and the half maximal inhibitory concentration was approximately 155 μM. G-Ro inhibited strongly thrombin-elevated [Ca2+]i, which was strongly increased by A-kinase inhibitor Rp-8-Br-cAMPS compared to G-kinase inhibitor Rp-8-Br-cGMPS. G-Ro increased the level of cAMP and subsequently elevated the phosphorylation of inositol 1, 4, 5-triphosphate receptor I (IP3RI) (Ser1756) to inhibit [Ca2+]i mobilization in thrombin-induced platelet aggregation. Phosphorylation of IP3RI (Ser1756) by G-Ro was decreased by PKA inhibitor Rp-8-Br-cAMPS. In addition, G-Ro inhibited thrombin-induced phosphorylation of ERK 2 (42 kDa), indicating inhibition of Ca2+ influx across plasma membrane. We demonstrate that G-Ro upregulates cAMP-dependent IP3RI (Ser1756) phosphorylation and downregulates phosphorylation of ERK 2 (42 kDa) to decrease thrombin-elevated [Ca2+]i, which contributes to inhibition of ATP and serotonin release, and p-selectin expression. These results indicate that G-Ro in Panax ginseng is a beneficial novel Ca2+-antagonistic compound and may prevent platelet aggregation-mediated thrombotic disease.

Vasodilator-stimulated phosphoprotein-phosphorylation by ginsenoside Ro inhibits fibrinogen binding to αIIb/β3 in thrombin-induced human platelets

“…The phosphorylation of IP 3 RI is connected to inhibition of [Ca 2+ ] i mobilization by IP 3 , and the phosphorylation of VASP contributes to inhibition of fibrinogen binding to αIIb/β 3 . In a previous report, we found that G-Ro inhibits thrombin-elevated [Ca 2+ ] i mobilization by phosphorylating IP 3 RI in a cAMP-dependent manner [22] . This means that G-Ro may be involved in inhibition of fibrinogen binding to αIIb/β 3 by decreasing [Ca 2+ ] i , and increasing cAMP.…”

“…It is known that p-selectin is released by Ca 2+ , and subsequently interacts with monocyte to trigger inflammation [34] . G-Ro in a Ca 2+ -antagonistic action inhibited thrombin-induced expression of p-selectin [22] , which means that the decrease of Ca 2+ level by G-Ro might involve in inhibition of inflammation by suppressing thrombin-induced p-selectin secretion. This is also evidenced by results that G-Ro had anti-inflammatory activity in vivo and in vitro [35] , [36] .…”

Short‐Term E‐Cigarette Exposure Increases the Risk of Thrombogenesis and Enhances Platelet Function in Mice

“…It was previously shown that phosphorylation of Akt and/or ERK plays a critical role in platelet function,60, 61, 62 and supports thrombus formation 63, 64. Thus, we examined whether e‐cigarettes exert any effect on these 2 markers of platelet activation.…”

20(S)-ginsenoside Rg3 inhibits glycoprotein IIb/IIIa activation in human platelets

“…The mechanism of G-Rg3 inhibitory effect on αIIb/ β 3 function was not clear, but our results suggested that this inhibitory effect was attributed cAMP/VASP Ser 157 signaling pathway. Furthermore, it has been reported that antiplatelet compounds, such as Korean red ginseng extract, ginsenoside Rp1 and ginsenoside Ro increase cyclic AMP levels [16][17]20]. These reports also suggest that the inhibitory action of ginseng saponins on platelet activation might be caused by increased cyclic AMP levels.…”

“…However, G-Ro and G-Rg3 (20S) exert suppression of human platelet aggregation [9]. Thus, in the present study, I first examined the effect of G-Ro on cyclic AMP concentration in human platelets and verified its cyclic AMPelevating effect [17]. The current study focused on the G-Rg3induced increase in cyclic AMP level.…”