• 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.

• Molecules and Cells
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• v.43 no.8
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• pp.718-727
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• 2020

The imbalance between the proliferation and apoptosis of B-cell precursors is an important contributor to the pathogenesis of B-cell precursor acute lymphoblastic leukemia (BCP-ALL), while its specific regulatory mechanism remains perplexing. This study aimed to expound the underlying mechanism of the proliferation and apoptosis of BCP-ALL cells from the perspective of non-coding RNA. In this study, long non-coding RNA colorectal neoplasia differentially expressed (LncRNA CRNDE) was upregulated in the bone marrow of BCP-ALL patients and BCP-ALL cell lines (NALM-6 and RS4;11). Functionally, LncRNA CRNDE knockdown restrained cell proliferation and boosted cell apoptosis in NALM-6 and RS4;11 cells. The subsequent investigation confirmed that LncRNA CRNDE bound to miR-345-5p and negatively regulated miR-345-5p expression. The overexpression of miR-345-5p suppressed cell proliferation and boosted cell apoptosis in NALM-6 and RS4;11 cells. Further experiments revealed that miR-345-5p downregulated cyclic AMP response element-binding protein (CREB) expression by targeting its mRNA directly. CREB overexpression reversed the effect of miR-345-5p mimic on cell proliferation and apoptosis in NALM-6 and RS4;11 cells. Finally, in vivo experiments showed that LncRNA CRNDE knockdown prolonged the survival of mice xenotransplanted with NALM-6 cells. In conclusion, LncRNA CRNDE upregulated CREB expression by suppressing miR-345-5p, thus promoting cell proliferation and reducing cell apoptosis in BCP-ALL.

• Journal of Ginseng Research
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• v.45 no.5
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• pp.555-564
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• 2021

Background: Ginsenosides of Panax ginseng are used to enhance skin health and beauty. The present study aimed to investigate the potential use of ginsenoside Rf (Rf) from Panax ginseng as a new anti-pigmentation agent. Methods: The anti-melanogenic effects of Rf were explored. The transcriptional activity of the cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) and the expression levels of tyrosinase, microphthalmia-associated transcription factor (MITF), and tyrosinase-related proteins (Tyrps) were evaluated in melanocytes and UV-irradiated ex vivo human skin. Results: Rf significantly inhibited Forskolin (FSK) or UV-stimulated melanogenesis. Consistently, cellular tyrosinase activity and levels of MITF, tyrosinase, and Tyrps were downregulated. Furthermore, Rf suppressed MITF promoter activity, which was stimulated by FSK or CREB-regulated transcription coactivator 3 (CRTC3) overexpression. Increased CREB phosphorylation and protein kinase A (PKA) activity induced by FSK were also mitigated in the presence of Rf. Conclusion: Rf can be used as a reliable anti-pigmentation agent, which has a scientifically confirmed and reproducible action mechanism, via inhibition of CREB/MITF pathway.

• Molecules and Cells
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• v.37 no.8
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• pp.613-619
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• 2014

The optic nerve often suffers regenerative failure after injury, leading to serious visual impairment such as glaucoma. The main inhibitory factors, including Nogo-A, oligodendrocyte myelin glycoprotein, and myelin-associated glycoprotein, exert their inhibitory effects on axonal growth through the same receptor, the Nogo-66 receptor (NgR). Oncomodulin (OM), a calcium-binding protein with a molecular weight of an ~12 kDa, which is secreted from activated macrophages, has been demonstrated to have high and specific affinity for retinal ganglion cells (RGC) and promote greater axonal regeneration than other known polypeptide growth factors. Protamine has been reported to effectively deliver small interference RNA (siRNA) into cells. Accordingly, a fusion protein of OM and truncated protamine (tp) may be used as a vehicle for the delivery of NgR siRNA into RGC for gene therapy. To test this hypothesis, we constructed OM and tp fusion protein (OM/tp) expression vectors. Using the indirect immunofluorescence labeling method, OM/tp fusion proteins were found to have a high affinity for RGC. The gel shift assay showed that the OM/tp fusion proteins retained the capacity to bind to DNA. Using OM/tp fusion proteins as a delivery tool, the siRNA of NgR was effectively transfected into cells and significantly down-regulated NgR expression levels. More importantly, OM/tp-NgR siRNA dramatically promoted axonal growth of RGC compared with the application of OM/tp recombinant protein or NgR siRNA alone in vitro. In addition, OM/tp-NgR siRNA highly elevated intracellular cyclic adenosine monophosphate (cAMP) levels and inhibited activation of the Ras homolog gene family, member A (RhoA). Taken together, our data demonstrated that the recombinant OM/tp fusion proteins retained the functions of both OM and tp, and that OM/tp-NgR siRNA might potentially be used for the treatment of optic nerve injury.

• Natural Product Sciences
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• v.22 no.4
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• pp.246-251
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• 2016

This study investigated the effects of (-)-sesamin on memory deficits in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned mouse model of Parkinson's disease (PD). MPTP lesion (30 mg/kg/day, 5 days) in mice showed memory deficits including habit learning memory and spatial memory. However, treatment with (-)-sesamin (25 and 50 mg/kg) for 21 days ameliorated memory deficits in MPTP-lesioned mouse model of PD: (-)-sesamin at both doses improved decreases in the retention latency time of the passive avoidance test and the levels of dopamine, norepinephrine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid, improved the decreased transfer latency time of the elevated plus-maze test, reduced the increased expression of N-methyl-D-aspartate (NMDA) receptor, and increased the reduced phosphorylation of extracellular signal-regulated kinase (ERK1/2) and cyclic AMP-response element binding protein (CREB). These results suggest that (-)-sesamin has protective effects on both habit learning memory and spatial memory deficits via the dopaminergic neurons and NMDA receptor-ERK1/2-CREB system in MPTP-lesioned mouse model of PD, respectively. Therefore, (-)-sesamin may serve as an adjuvant phytonutrient for memory deficits in PD patients.

• Natural Product Sciences
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• v.24 no.2
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• pp.99-102
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• 2018

This study investigated the effects of ombuoside, a flavonol glycoside, on dopamine biosynthesis in PC12 cells. Ombuoside at concentrations of 1, 5, and $10{\mu}M$ increased intracellular dopamine levels at 1 - 24 h. Ombuoside (1, 5, and $10{\mu}M$) also significantly increased the phosphorylation of tyrosine hydroxylase (TH) (Ser40) and cyclic AMP-response element binding protein (CREB) (Ser133) at 0.5 - 6 h. In addition, ombuoside (1, 5, and $10{\mu}M$) combined with L-DOPA (20, 100, and $200{\mu}M$) further increased intracellular dopamine levels for 24 h compared to L-DOPA alone. These results suggest that ombuoside regulates dopamine biosynthesis by modulating TH and CREB activation in PC12 cells.

• Molecules and Cells
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• v.23 no.1
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• pp.23-29
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• 2007

Cyclic AMP-responsive element binding protein (CREB) is known to be associated with angiogenesis. In the present study we investigated the possible role of CREB in the expression of vascular endothelial growth factor (VEGF) by mouse macrophages. Over-expression of CREB increased VEGF secretion by cells of the RAW264.7 mouse macrophage cell line. It also increased the promoter activity of a mouse reporter driven by the VEGF promoter, while a dominant negative CREB (DN-CREB) abrogated the activity, suggesting that CREB mediates VEGF transcription. Forskolin, an adenylyl cyclase activator, stimulated VEGF transcription, and the PKA inhibitor H89 abolished this effect. IFN-${\gamma}$, a potent cytokine, stimulated VEGF expression only in part through the PKA-CREB pathway. These results indicate that PKA phosphorylates CREB and so induces VEGF gene expression. An analysis of mutant promoters revealed that one of the putative CREB responsive elements (CREs), at -399 ~ -388 in the promoter, is critical for CREB-mediated VEGF promoter activity, and the significance of this CRE was confirmed by chromatin immunoprecipitation assays.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.1
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• pp.63-70
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• 2018

Cilostazol is a selective inhibitor of type 3 phosphodiesterase (PDE3) and has been widely used as an antiplatelet agent. Cilostazol mediates this activity through effects on the cyclic adenosine monophosphate (cAMP) signaling cascade. Recently, it has attracted attention as a neuroprotective agent. However, little is known about cilostazol's effect on excitotoxicity induced neuronal cell death. Therefore, this study evaluated the neuroprotective effect of cilostazol treatment against hippocampal neuronal damage in a mouse model of kainic acid (KA)-induced neuronal loss. Cilostazol pretreatment reduced KA-induced seizure scores and hippocampal neuron death. In addition, cilostazol pretreatment increased cAMP response element-binding protein (CREB) phosphorylation and decreased neuroinflammation. These observations suggest that cilostazol may have beneficial therapeutic effects on seizure activity and other neurological diseases associated with excitotoxicity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.4
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• pp.484-491
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• 2016

The present study investigated the effect of Sinetrol-XPur (polyphenolic Citrus spp. and Paullinia cupana Kunth dry extract) and defined the action mode for cyclic adenosine monophosphate (cAMP)-dependent uncoupling protein (UCP)-2 activation. Leptin-deficient obese mice were treated with two different doses, 100 mg/kg body weight (BW) and 300 mg/kg BW of each AIN93G supplement, for 7 weeks. Treatment of obese mice with both low and high doses of Sinetrol-XPur significantly reduced body weight gain compared to control obese mice. White adipose tissue weight of mice was reduced by 30.96% in high dose-supplemented groups. Serum total cholesterol and triglyceride were reduced by a high dose of Sinetrol-XPur by 20.02% and 30.96%, respectively. Serum level of high density lipoprotein (HDL) was significantly increased by treatment with both doses, as the ratio of HDL to low density lipoprotein increased by 138.78% and 171.49%, respectively. Regarding expression of biochemical factors related to lipid metabolism, fatty acid synthase significantly decreased and UCP-2 increased upon treatment with a high dose of Sinetrol-XPur, but there was no significant difference in lipoprotein lipase and hormone-sensitive lipase. To define cellular mechanism, intracellular cAMP levels in 3T3-L1 adipocytes significantly increased in a dose-dependent manner over the range of $50{\sim}250{\mu}m/mL$. The phosphodiesterase (PDE) inhibitor 3-isobutyl-1-methylxanthine clearly blocked cAMP, suggesting that Sinetrol-XPur promotes lipolysis of adipocytes through inhibition of cAMP-dependent PDE, resulting in induction of cAMP response element binding protein and UCP-2. These results suggest that Sinetrol-XPur supplementation is a viable option for reducing body weight and fat by improving serum lipid profiles and genetic expression of lipid metabolic factors, especially activation of cAMP-dependent UCP-2.

• Journal of Microbiology and Biotechnology
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• v.26 no.3
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• pp.627-636
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• 2016

The causative agent of pandemic cholera, Vibrio cholerae, infects the anaerobic environment of the human intestine. Production of cholera toxin (CT), a major virulence factor of V. cholerae, is highly induced during anaerobic respiration with trimethylamine N-oxide (TMAO) as an alternative electron acceptor. However, the molecular mechanism of TMAO-stimulated CT production is not fully understood. Herein, we reveal that CT production during anaerobic TMAO respiration is affected by glucose fermentation. When the seventh pandemic V. cholerae O1 strain N16961 was grown with TMAO and additional glucose, CT production was markedly reduced. Furthermore, an N16961 Δcrp mutant, devoid of cyclic AMP receptor protein (CRP), was defective in CT production during growth by anaerobic TMAO respiration, further suggesting a role of glucose metabolism in regulating TMAO-mediated CT production. TMAO reductase activity was noticeably decreased when grown together with glucose or by mutation of the crp gene. A CRP binding region was identified in the promoter region of the torD gene, which encodes a structural subunit of the TMAO reductase. Gel shift assays further confirmed the binding of purified CRP to the torD promoter sequence. Together, our results suggest that the bacterial ability to respire using TMAO is controlled by CRP, whose activity is dependent on glucose availability. Our results reveal a novel mechanism for the regulation of major virulence factor production by V. cholerae under anaerobic growth conditions.