• Biomedical Science Letters
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• v.23 no.3
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• pp.251-260
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• 2017

Platelet activation is essential at the sites of vascular injury, which leads to hemostasis through adhesion, aggregation, and secretion process. However, potent and continuous platelet activation may be an important reason of circulatory disorders. Therefore, proper regulation of platelet activation may be an effective treatment for vascular diseases. In this research, inhibitory effects of cordycepin (3'-deoxyadenosine) on platelet activation were determined. As the results, cordycepin increased cAMP and cGMP, which are intracellular $Ca^{2+}$-antagonists. In addition, cordycepin reduced collagen-elevated $[Ca^{2+}]_i$ mobilization, which was increased by a cAMP-dependent protein kinase (PKA) inhibitor (Rp-8-Br-cAMPS), but not a cGMP-protein kinase (PKG) inhibitor (Rp-8-Br-cGMPS). Furthermore, cordycepin increased $IP_3RI$ ($Ser^{1756}$) phosphorylation, indicating inhibition of $IP_3$-mediated $Ca^{2+}$ release from internal store via the $IP_3RI$, which was strongly inhibited by Rp-8-Br-cAMPS, but was not so much inhibited by Rp-8-Br-cGMPS. These results suggest that the reduction of $[Ca^{2+}]_i$ mobilization is caused by the cAMP/A-kinase-dependent $IP_3RI$ ($Ser^{1756}$) phosphorylation. In addition, cordycepin increased the phosphorylation of VASP ($Ser^{157}$) known as PKA substrate, but not VASP ($Ser^{239}$) known as PKG substrate. Cordycepin-induced VASP ($Ser^{157}$) phosphorylation was inhibited by Rp-8-Br-cAMPS, but was not inhibited by Rp-8-Br-cGMPS, and cordycepin inhibited collagen-induced fibrinogen binding to ${\alpha}IIb/{\beta}_3$, which was increased by Rp-8-Br-cAMPS, but was not inhibited by Rp-8-Br-cGMPS. These results suggest that the inhibition of ${\alpha}IIb/{\beta}_3$ activation is caused by the cAMP/A-kinase-dependent VASP ($Ser^{157}$) phosphorylation. In conclusion, these results demonstrate that inhibitory effects of cordycepin on platelet activation were due to inhibition of $[Ca^{2+}]_i$ mobilization through cAMP-dependent $IP_3RI$ ($Ser^{1756}$) phosphorylation and suppression of ${\alpha}IIb/{\beta}_3$ activation through cAMP-dependent VASP ($Ser^{157}$) phosphorylation. These results strongly indicated that cordycepin might have therapeutic or preventive potential for platelet activation-mediated disorders including thrombosis, atherosclerosis, myocardial infarction, or cardiovascular disease.

• YAKHAK HOEJI
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• v.49 no.4
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• pp.260-267
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• 2005

[ $PGE_1$ ] is an endogenous substance of potent vasodialator as well as inhibitor of platelet aggregation. It has been used therapeutically in peripheral arterial occlusive disease and impotence. Intracavernous injection of $PGE_1$ for erectile dysfunction has been established for several years as a treatment option for erectile dysfunction of diverse etiologies, but this mode of administration is limited by penile discomfort, pain at the injection site, inconvenience and noncompliance. As the matter of worse, the $\beta-hydroxy$ moiety of $PGE_1$ is extremely susceptible to dehydration in solution to give inactive $PGA_1$ and $PGB_1$. For the improvement of stability, rapid absorption at action site and the convenience of application, $PGE_1$ was formulated as urethral suppositories of three types of formulations, such as PEG, witepsol, and the mixture of PEG and witepsol. The stability test of $PGE_1$ and the release test in urinary suppositories were performed. Futhermore, the effect of enhancers and vehicle composition on the penetration of $PGE_1$ through excised rat skin was evaluated by permeability coefficient and enhancement ratio.

• Biomolecules & Therapeutics
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• v.31 no.1
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• pp.127-138
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• 2023

Glycogen synthase kinase-3β (GSK-3β) is an important serine/threonine kinase that implicates in multiple cellular processes and links with the neurodegenerative diseases including Alzheimer's disease (AD). In this study, structure-based virtual screening was performed to search database for compounds targeting GSK-3β from Enamine's screening collection. Of the top-ranked compounds, 7 primary hits underwent a luminescent kinase assay and a cell assay using human neuroblastoma SH-SY5Y cells expressing Tau repeat domain (Tau_RD) with pro-aggregant mutation ΔK280. In the kinase assay for these 7 compounds, residual GSK-3β activities ranged from 36.1% to 90.0% were detected at the IC₅₀ of SB-216763. In the cell assay, only compounds VB-030 and VB-037 reduced Tau aggregation in SH-SY5Y cells expressing ΔK280 Tau_RD-DsRed folding reporter. In SH-SY5Y cells expressing ΔK280 Tau_RD, neither VB-030 nor VB-037 increased expression of GSK-3α Ser21 or GSK-3β Ser9. Among extracellular signal-regulated kinase (ERK), AKT serine/threonine kinase 1 (AKT), mitogen-activated protein kinase 14 (P38) and mitogenactivated protein kinase 8 (JNK) which modulate Tau phosphorylation, VB-037 attenuated active phosphorylation of P38 Thr180/ Tyr182, whereas VB-030 had no effect on the phosphorylation status of ERK, AKT, P38 or JNK. However, both VB-030 and VB-037 reduced endogenous Tau phosphorylation at Ser202, Thr231, Ser396 and Ser404 in neuronally differentiated SH-SY5Y expressing ΔK280 Tau_RD. In addition, VB-030 and VB-037 further improved neuronal survival and/or neurite length and branch in mouse hippocampal primary culture under Tau cytotoxicity. Overall, through inhibiting GSK-3β kinase activity and/or p-P38 (Thr180/Tyr182), both compounds may serve as promising candidates to reduce Tau aggregation/cytotoxicity for AD treatment.

• Research in Plant Disease
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• v.16 no.3
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• pp.259-265
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• 2010

Pepper mild mosaic virus(PMMoV) and Cucumber mosaic virus (CMV) are important pathogens in various vegetable crops worldwide. We have found that hot water extract of Phellinus linteus mycelium strongly inhibit PMMoV and CMV infection. Based on these results, the inhibitor named as 'PLM-WE1' formulated from extract of Phellinus linteus mycelium was tested for its inhibitory effects on PMMoV and CMV infection to each local lesion host plant (Nicotiana glutinosa: PMMoV, Chenopodium amaranticolor: CMV). Pretreatment effect of PLM-WE1 against infections of each virus (PMMoV and CMV) to local host plant was measured to be 99.2% to PMMoV and 80.3% to CMV, and its permeability effect was measured to be 45.0% to PMMoV and 41.9% to CMV. Duration of inhibitory activity of PLM-WE1 against PMMoV infection on N. glutinosa was maintained for 3 days at 75% inhibition level and CMV infection on C. amaranticolor maintained for 3 days at 62% inhibition level. Inhibitory effects on systemic host plants of PLM-WE1 were measured to be 75~85% to PMMoV and 75% to CMV. Under electron microscope, PMMoV particles were not denatured or aggregated by mixing PLM-WE1. It is suggested that the mode of action of PLM-WE1 differ from that of inactivation due to the aggregation of viruses. The methanol extract of P. linteus mycelium was sequentially partitioned with haxane, ethyl acetate, BuOH and $H_2O$. The $H_2O$ fraction was showed high activity than the other fractions. The active compound was isolated with a partial acid hydrolysis, fractional precipitation with ethanol. The inhibitory effect of the precipitate isolated from 70% ethanol fraction was 99.1% to PMMoV and 88.0% to CMV. The structure of isolated compound was determined by $^1H$-NMR and $^{13}C$-NMR. This compound was identified as a polysaccharide consisting alpha or beta-glucan.