• International Journal of Oral Biology
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• v.35 no.3
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• pp.107-111
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• 2010

Treponema denticola is a gram-negative anaerobe that can cause periodontal disease. The adhesion of this bacterium to host tissues is considered to be the primary event in the colonization and infection of a host. Fibrinogen is generally found in damaged tissues resulting from periodontitis. The binding ability of T. denticola to fibrinogen may therefore be an important virulence factor in inducing periodontal diseases. It has been reported recently that oral spirochetes can be labeled with fluorescent fatty acids and we speculated that this labeling method could be used in an oral spirochete binding assay. The binding of several different strains of T. denticola to immobilized human fibrinogen was therefore tested using the fluorescent fatty acid labeling method. In the case of immobilized fibrinogen, the T. denticola ATCC 35405 strain showed saturable binding to immobilized fibrinogen. Indeed, all four different T. denticola strains tested in this experiment, T. denticola ATCC 35405, T. denticola ATCC 33520, T. denticola ATCC 35404 and T. denticola OTK showed binding to fibrinogen. The fluorescent fatty acid labeling method thus shows utility in binding assays for T. denticola, different strains of which can generally bind to immobilized fibrinogen.

• Journal of Ginseng Research
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• v.40 no.4
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• pp.359-365
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• 2016

Background: Glycoprotein IIb/IIIa (${\alpha}aIIb/{\beta}_3$) is involved in platelet adhesion, and triggers a series of intracellular signaling cascades, leading to platelet shape change, granule secretion, and clot retraction. In this study, we evaluated the effect of ginsenoside Ro (G-Ro) on the binding of fibrinogen to ${\alpha}aIIb/{\beta}_3$. Methods: We investigated the effect of G-Ro on regulation of signaling molecules affecting the binding of fibrinogen to ${\alpha}aIIb/{\beta}_3$, and its final reaction, clot retraction. Results: We found that G-Ro dose-dependently inhibited thrombin-induced platelet aggregation and attenuated the binding of fibrinogen to ${\alpha}aIIb/{\beta}_3$ by phosphorylating cyclic adenosine monophosphate (cAMP)-dependently vasodilator-stimulated phosphoprotein (VASP; $Ser^{157}$). In addition, G-Ro strongly abrogated the clot retraction reflecting the intensification of thrombus. Conclusion: We demonstrate that G-Ro is a beneficial novel compound inhibiting ${\alpha}aIIb/{\beta}_3$-mediated fibrinogen binding, and may prevent platelet aggregation-mediated thrombotic disease.

• Journal of Ginseng Research
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• v.40 no.1
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• pp.76-85
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• 2016

Background: Binding of adhesive proteins (i.e., fibrinogen, fibronectin, vitronectin) to platelet integrin glycoprotein IIb/IIIa (${\alpha}IIb/{\beta}3$) by various agonists (thrombin, collagen, adenosine diphosphate) involve in strength of thrombus. This study was carried out to evaluate the antiplatelet effect of total saponin from Korean Red Ginseng (KRG-TS) by investigating whether KRG-TS inhibits thrombin-induced binding of fibrinogen and fibronectin to ${\alpha}IIb/{\beta}3$. Methods: We investigated the effect of KRG-TS on phosphorylation of vasodilator-stimulated phosphoprotein (VASP) and dephosphorylation of phosphatidylinositol 3-kinase (PI3K) and Akt, affecting binding of fibrinogen and fibronectin to ${\alpha}IIb/{\beta}3$, and clot retraction. Results: KRG-TS had an antiplatelet effect by inhibiting the binding of fibrinogen and fibronectin to ${\alpha}IIb/{\beta}3$ via phosphorylation of VASP ($Ser^{157}$), and dephosphorylation of PI3K and Akt on thrombin-induced platelet aggregation. Moreover, A-kinase inhibitor Rp-8-Br-cyclic adenosine monophosphates (cAMPs) reduced KRG-TS-increased VASP ($Ser^{157}$) phosphorylation, and increased KRG-TS-inhibited fibrinogen-, and fibronectin-binding to ${\alpha}IIb/{\beta}3$. These findings indicate that KRG-TS interferes with the binding of fibrinogen and fibronectin to ${\alpha}IIb/{\beta}3$ via cAMP-dependent phosphorylation of VASP ($Ser^{157}$). In addition, KRG-TS decreased the rate of clot retraction, reflecting inhibition of ${\alpha}IIb/{\beta}3$ activation. In this study, we clarified ginsenoside Ro (G-Ro) in KRG-TS inhibited thrombin-induced platelet aggregation via both inhibition of $[Ca^{2+}]_i$ mobilization and increase of cAMP production. Conclusion: These results strongly indicate that KRG-TS is a beneficial herbal substance inhibiting fibrinogen-, and fibronectin-binding to ${\alpha}IIb/{\beta}3$, and clot retraction, and may prevent platelet ${\alpha}IIb/{\beta}3$-mediated thrombotic disease. In addition, we demonstrate that G-Ro is a novel compound with antiplatelet characteristics of KRG-TS.

• Biomolecules & Therapeutics
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• v.23 no.1
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• pp.60-70
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• 2015

In this study, we investigated the effects of cordycepin-enriched (CE)-WIB801C, a n-butanol extract of Cordyceps militaris-hypha on collagen-stimulated platelet aggregation. CE-WIB801C dose dependently inhibited collagen-induced platelet aggregation, and had a synergistic effect together with cordycepin (W-cordycepin) from CE-WIB801C on the inhibition of collagen-induced platelet aggregation. CE-WIB801C and cordycepin stimulated the phosphorylation of VASP ($Ser^{157}$) and the dephosphorylation of PI3K and Akt, and inhibited the binding of fibrinogen to glycoprotein IIb/IIIa (${\alpha}IIb/{\beta}3$) and the release of ATP and serotonin in collagen-induced platelet aggregation. A-kinase inhibitor Rp-8-Br-cAMPS reduced CE-WIB801C-, and cordycepin-increased VASP ($Ser^{157}$) phosphorylation, and increased CE-WIB801C-, and cordycepin-inhibited the fibrinogen binding to ${\alpha}IIb/{\beta}3$. Therefore, we demonstrate that CE-WIB801C-, and cordycepin-inhibited fibrinogen binding to ${\alpha}IIb/{\beta}3$are due to stimulation of cAMP-dependent phosphorylation of VASP ($Ser^{157}$), and inhibition of PI3K/Akt phosphorylation. These results strongly indicate that CE-WIB801C and cordycepin may have preventive or therapeutic potential for platelet aggregation-mediated diseases, such as thrombosis, myocardial infarction, atherosclerosis, and ischemic cerebrovascular disease.

• BMB Reports
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• v.31 no.5
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• pp.515-518
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• 1998

Adhesive interaction of the platelet glycoprotien IIb-IIIa (GP IIb-IIIa) with a plasma protein, such as fibrinogen, plays an important role in thrombosis and hemostasis. The specific sequence Arg-Gly-Asp (RGD) is critical for the binding of fibrinogen to platelet. To examine and characterize the GP IIb-IIIa antagonist from natural sources, we have developed a simple enzyme-linked immunosorbant assay (ELISA) system. The GP IIb-IIIa complex was purified to homogeneity from platelet Iysates by the combination of two affinity chromatographic methods using the synthetic RGD peptide (GRGDSPK)-immobilized Sepharose and wheat germ lectin-Sepharose. The synthetic peptide GRGDSP inhibits GP IIb-IIIa binding to immobilized fibrinogen with an $IC_{50}$ of $1.5\;{\mu}M$. Venoms of three different snake species and a Korean scolopendra extract have strong antagonistic activities for the binding of human fibrinogen to the platelet GP IIb-IIIa complex. The $IC_{50}$ values of the snake venom s and scolopendra were in the range of $5.5\;{\mu}g$ to $60\;{\mu}g$. These results provide meaningful information for developing antiplatelet agents.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.2
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• pp.99-107
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• 2017

A species of Cordyceps, an ingredient in Chinese traditional medicine well-known for its major component, cordycepin (3'-deoxyadenosine), has been known to have antiplatelet effects; however, its effects on regulation of phosphoprotein have not been fully elucidated. In this study, we investigated how cordycepin regulates the phosphoprotein, including phosphatidylinositol 3-kinase (PI3K)/Akt and p38, to inhibit platelet aggregation, which are concerned with fibrinogen binding to glycoprotein IIb/IIIa (${\alpha}IIb/{\beta}_3$) and granule secretion in platelets. Our finding suggests that cordycepin inhibits collagen-induced platelet aggregation with $261.1{\mu}M$ of $IC_{50}$ and also inhibits fibrinogen binding to ${\alpha}IIb/{\beta}_3$ by a suppression of PI3K/Akt phosphorylation in a dose dependent manner. In addition, cordycepin further showed to inhibit collagen-induced p38 phosphorylation, reducing granule secretion (i.e. ATP- and serotonin-release) and thromboxane $A_2$ ($TXA_2$) production without regulating cyclooxygenase-1 (COX-1) and thromboxane A synthase (TXAS) activities, as well as phospholipase $C-{\gamma}_2$ ($PLC-{\gamma}_2$) phosphorylation. In conclusion, these results demonstrate that cordycepin-mediated antiplatelet effects were due to the inhibition of fibrinogen binding to ${\alpha}IIb/{\beta}_3$ via the suppression of PI3K/Akt phosphorylation and inhibition of granule secretion & $TXA_2$ production by suppressing p38 phosphorylation. These results strongly indicate that cordycepin might have therapeutic or preventive potential for platelet aggregation-mediated disorders, regulating the phosphoprotein, including PI3K/Akt and p38.

• Biomedical Science Letters
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• v.27 no.4
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• pp.270-276
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• 2021

Physiological agents trigger a signaling process called "inside-out signaling" and activated platelets promote adhesion, granule release, and conformational changes of glycoprotein IIb/IIIa (αIIb/β₃). Activated αIIb/β₃ interacts with fibrinogen and initiates a second signaling step called "external signaling". These two signaling pathways can cause hemostasis or thrombosis, and thrombosis is a possible medical problem in arterial and venous vessels, and platelet-mediated thrombosis is a major cause of cardiovascular disease (CVD). Therefore, modulating platelet activity is important for platelet-mediated thrombosis and cardiovascular disease. Esculetin is a coumarin-based physiologically active 6,7-dihydroxy derivative known to have pharmacological activity against obesity, diabetes, renal failure and CVD. Although some studies have confirmed the effects of esculetin in human platelet activation and experimental mouse models, it is not clear how esculetin has antiplatelet and antithrombotic effects. We confirmed the effect and mechanism of action of escultein on human platelets induced by collagen. As a result, esculetin decreased Ca²⁺ recruitment through upregulation of inositol 1, 4, 5-triphosphate receptor. In addition, esculetin upregulates cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP)-dependent pathways and inhibits fibrinogen binding and thrombus contraction. Our results demonstrate the antiplatelet effect and antithrombotic effect of esculetin in human platelets. Therefore, we suggest that esculetin could be a potential phytochemical for the prevention of thrombus-mediated CVD.

• 대한임상약리학회:학술대회논문집
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• 1998.12a
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• pp.44-44
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• 1998

• Biomedical Science Letters
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• v.25 no.2
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• pp.123-130
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• 2019

Platelet aggregation is essential for hemostatic process in case of blood vessels damages. However, excessive platelet aggregation can cause cardiovascular disorders including atherosclerosis, thrombosis and myocardial infarction. Scopoletin is usually found in the roots of genus Scopolia or Artemisia, and is known to have anticoagulant and anti-malarial effects. This study investigated the effect of scopoletin on human platelet aggregation induced by U46619, an analogue of thromboxane $A_2(TXA_2)$. Scopoletin had anti-platelet effects by down-regulating $TXA_2$ and intracellular $Ca^{2+}$ mobilization ($[Ca^{2+}]_i$), the aggregation-inducing molecules generated in activated platelets. On the other hand, scopoletin increased the levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are known to be intracellular $Ca^{2+}$ antagonists. This resulted in inhibition of fibrinogen binding to ${\alpha}IIb/{\beta}_3$ in U46619-induced human platelet aggregation. In addition, scopoletin inhibited the release of adenosine trisphosphate (ATP) in dose-dependent manner. This result means that the aggregation amplification activity through the granule secretion in platelets was suppressed by scopoletin. Therefore, we demonstrated that scopoletin has a potent antiplatelet effect and is highly likely to prevent platelet-derived vascular disease.

• Natural Product Sciences
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• v.26 no.4
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• pp.295-302
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• 2020

Cudrania tricuspidata (C. tricuspidata) is a deciduous tree found in Japan, China and Korea. The root, stems, bark and fruit of C. tricuspidata has been used as traditional herbal remedies such as eczema, mumps, acute arthritis and tuberculosis. In this study, we investigated the potential efficacies of this natural compound by focusing on the inhibitory effect of cudraxanthone L (CXL) isolated from the roots of C. tricuspidata on human platelet aggregation. Our study focused on the action of CXL on collagen-stimulated human platelet aggregation, inhibition of platelet signaling molecules such as fibrinogen binding, intracellular calcium mobilization, fibronectin adhesion, dense granule secretion, and thromboxane A2 secretion. In addition, we investigated the inhibitory effect of CXL on thrombin-induced clot retraction. Our results showed that CXL inhibited collagen-induced human platelet aggregation, intracellular calcium mobilization, fibrinogen binding, fibronectin adhesion and clot retraction without cytotoxicity. Therefore, we confirmed that CXL has inhibitory effects on human platelet activities and has potential value as a natural substance for preventing thrombosis.