• Nutrition Research and Practice
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• 제9권6호
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• pp.606-612
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• 2015

BACKGROUND/OBJECTIVES: Several medicinal properties of Smilax china L. have been studied including antioxidant, anti-inflammatory, and anti-cancer effects. However, the antiobesity activity and mechanism by which the water-soluble fraction of this plant mediates its effects are not clear. In the present study, we investigated the lipolytic actions of the water-soluble fraction of Smilax china L. leaf ethanol extract (wsSCLE) in 3T3-L1 adipocytes. MATERIALS/METHODS: The wsSCLE was identified by measuring the total polyphenol and flavonoid content. The wsSCLE was evaluated for its effects on cell viability, lipid accumulation, glycerol, and cyclic adenosine monophosphate (cAMP) contents. In addition, western blot analysis was used to evaluate the effects on protein kinase A (PKA), PKA substrates (PKAs), and hormone-sensitive lipase (HSL). For the lipid accumulation assay, 3T3-L1 adipocytes were treated with different doses of wsSCLE for 9 days starting 2 days post-confluence. In other cell experiments, mature 3T3-L1 adipocytes were treated for 24 h with wsSCLE. RESULTS: Results showed that treatment with wsSCLE at 0.05, 0.1, and 0.25 mg/mL had no effect on cell morphology and viability. Without evidence of toxicity, wsSCLE treatment decreased lipid accumulation compared with the untreated adipocyte controls as shown by the lower absorbance of Oil Red O stain. The wsSCLE significantly induced glycerol release and cAMP production in mature 3T3-L1 cells. Furthermore, protein levels of phosphorylated PKA, PKAs, and HSL significantly increased following wsSCLE treatment. CONCLUSION: These results demonstrate that the potential antiobesity activity of wsSCLE is at least in part due to the stimulation of cAMP-PKA-HSL signaling. In addition, the wsSCLE-stimulated lipolysis induced by the signaling is mediated via activation of the ${\beta}$-adrenergic receptor.

• 한국발생생물학회지:발생과생식
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• 제22권1호
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• pp.95-104
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• 2018

CREBZF (cAMP-response element binding protein zhangfei) is a member of ATF/CREB family, and which regulates various cellular functions by suppressing major factors with direct interaction. In this study, we have examined the expression of CREBZF on mouse endometrium during uterus estrous cycles and estrogen (E2) treatment. In uterus, CREBZF mRNA expression was higher than other organs and mRNA and protein of CREBZF was increased in proestrus phase and decreased in estrus phase. The expression of CREBZF in 3-weeks old mouse uterus was reduced by E2 injection in endometrium. In addition, the expression of progesterone receptor, a marker of E2 in ovariectomized mice was found to be strongly expressed in stroma, while CREBZF was only expressed in epithelium. Also, we conformed that E2-suppressed CREBZF was restored by co-injection of ICI 182,780, an estrogen receptor antagonist. Overall, these results suggest that CREBZF is regulated by estrogen and involved in ER signaling pathway in mouse uterus.

• 한국미생물·생명공학회지
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• 제38권4호
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• pp.349-361
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• 2010

본 총설에서는 아미노산의 공업적 생산균인 Corynebacterium glutamicum의 탄소 대사 및 이와 관련된 총체적 조절 메커니즘에 대한 최근의 연구를 정리하였다. C. glutamicum의 산업적 발효을 위한 기질로서 사용되는 당밀은 주로 sucrose, glucose, fructose로 이루어져 있으며, 이들 당은 phosphotransferase system을 통해서 수송된다. C. glutamicum의 탄소 대사 특징은 glucose가 다른 당이나 유기산 등과 함께 존재할 때, glucose와 이러한 탄소원 들을 동시에 대사한다. 그러나 glucose/glutamate 혹은 glucose/ethanol 등의 혼합물에서 는 탄소원의 순차적 이용으로 인해 나타나는 diauxic growth 현상을 나타내며, 이러한 carbon catabolite repression(CCR) 현상은 E. coli나 B. subtilis 등에서 알려진 것과는 다른 독특한 분자적 메커니즘과 조절 circuits을 가지고 있음이 밝혀지고 있다. C. glutamicum의 CRP homologue인 GlxR은 acetate 대사를 포함하여 glycolysis, gluconeogenesis 및 TCA cycle 등을 포함하는 중심탄소대사 조절 뿐만 아니라, 다양한 세포 기능의 조절에 관여하는 총체적 조절 단백질로서의 역할이 제시되고 있다. C. glutamicum의 adenylate cyclase(AC)는 막과 결합된 class IIIAC 로서, 막 단백질의 특성상 아직 규명되어 있지 않은 세포 외부의 환경 변화에 대응하여 세포 내의 cAMP합성 수준을 조절할 수 있는 sensor로 추정할 수 있다. 특히 C. glutamicum의 경우 배지내 glucose 를 비롯한 탄소원과 cAMP 농도와의 관련성이 E. coli에서 알려진 교과서적 지식과는 상반되게 변화하는 경향을 보이고 있어, cAMP signaling에 의한 세포 내 regulatory network 등은 향후 풀어야 할 의문으로 남아있다. 탄소대사 조절의 최상위에 존재하며 global 조절자인 GlxRcAMP 복합체 이외에도 차상위 전사조절 단백질로서 RamB, RamA, SugR 등이 존재하여 다양한 탄소대사를 조절한다. 최근 들어서는 새로운 탄소원으로서 대두되고 있는 biomass 관련 기질들을 이용할 수 있는 C. glutamucum 균주 구축을 통하여 이용 기질의 범위를 확대시키고자 하는 연구 및 탄소 대사와 관련하여 L-lysine의 발효 수율 혹은 생산성을 향상시키고자 하는 다양한 분자적 균주 육종 연구 등이 수행되고 있다.

• Mycobiology
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• 제39권3호
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• pp.143-150
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• 2011

The basidiomycete fungus Cryptococcus neoformans is an important pathogen of immunocompromised people. The ability of the fungus to sense its environment is critical for proliferation and the generation of infectious propagules, as well as for adaptation to the mammalian host during infection. The conserved cAMP/protein kinase A pathway makes an important contribution to sensing, as demonstrated by the phenotypes of mutants with pathway defects. These phenotypes include loss of the ability to mate and to elaborate the key virulence factors capsule and melanin. This review summarizes recent work that reveals new targets of the pathway, new phenotypic consequences of signaling defects, and a more detailed understanding of connections with other aspects of cryptococcal biology including iron regulation, pH sensing, and stress.

• BMB Reports
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• 제36권3호
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• pp.299-304
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• 2003

For deciphering the cyclic guanosine monophosphate (cGMP) signaling pathway, we employed chemical proteomics to identify the novel target molecules of cGMP. We used cGMP that was immobilized onto agarose beads with linkers directed at three different positions of cGMP. We performed a pull-down assay using the beads as baits on tissue lysates and identified 9 proteins by MALDI-TOF (Matrix-Assisted Laser Desorption/Ionization Time-of-Flight) mass spectrometry. Some of the identified proteins were previously known cGMP targets, including cGMP-dependent protein kinase and cGMP-stimulated phosphodiesterase. Surprisingly, some of the co-precipitated proteins were never formerly reported to associate with the cGMP signaling pathway. The competition binding assays showed that the interactions are not by nonspecific binding to either the linker or bead itself, but by specific binding to cGMP. Furthermore, we observed that the interactions are highly specific to cGMP against other nucleotides, such as cyclic adenosine monophosphate (cAMP) and 5'-GMP, which are structurally similar to cGMP. As one of the identified targets, MAPK1 was confirmed by immunoblotting with an anti-MAPK1 antibody. For further proof, we observed that the membrane-permeable cGMP (8-bromo cyclic GMP) stimulated mitogen-activated protein kinase 1 signaling in the treated cells. Our present study suggests that chemical proteomics can be a very useful and powerful technique for identifying the target proteins of small bioactive molecules.

• Journal of Ginseng Research
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• 제40권4호
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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.

• 한국자원식물학회지
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• 제30권6호
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• pp.647-653
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• 2017

Hepatic ischemia-reperfusion injury (HIRI) is linked with high mortality rate. Several agents have been developed so far to reduce the risk of HIRI. In this study, we investigated the effects of Acanthopanax senticosus extract (AS) on hepatic ischemia-reperfusion. To explore the protective effects of A. senticosus extract injection (ASI) on hepatic ischemia-reperfusion injury rats animal model were used. After the development of HIRI by using clamping method rats were then randomly divided into five groups. Different doses of AS were administered in HIRI rat model. The level of ALT, AST, and MDA content in serum were detected in sham and HIRI groups. The activity of SOD, MPO and $Ca^{2+}-ATPase$, content of MDA, and cAMP in hepatic tissue were also measured. Expression of Bcl-2 and Bax protein were detected by immunohistochemical staining method. Compared with sham group, ASI has the protective effect on the HIRI model in rats. Blood levels of ALT, AST, SOD, MPO, and MDA were significantly lower in ASI group compared with HIRI. Indeed SOD and $Ca^{2+}-ATPase$ activities, MDA content, and cAMP level were improved in ASI group. Furthermore, Bcl-2 and Bax protein were improved in ASI group compared with only HIRI group. These results suggest that AS may provide potential ameliorative therapy by inhibiting the damage signaling mechanism in hepatic ischemia/reperfusion injury model.

• The Korean Journal of Physiology and Pharmacology
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• 제9권6호
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• pp.333-339
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• 2005

B/K protein is a novel protein containing double C2-like domains. We examined the specific signaling pathway that regulates the transcription of B/K in PC12 cells. When the cells were treated with forskolin ($50{\mu}M$), B/K mRNA and protein levels were time-dependently decreased, reaching the lowest level at 3 or 4 hr, and thereafter returning to the control level. Chemicals such as dibutyryl-cAMP, cellpermeable cyclic AMP (cAMP) analogue and CGS21680, adenosine receptor $A_{2A}$ agonist, also repressed the B/K transcription. However, 1,9-dideoxyforskolin did not show inhibitory effect on B/K transcription, suggesting direct involvement of cAMP in the forskolin-induced inhibition of B/K transcription. Effect of forskolin, dibutyryl cAMP and CGS21680 was significantly reduced in PKA-deficient PC12 cell line (PC12-123.7). One cAMP-response element (CRE)-like sequence (B/K CLS) was found in the promoter region of B/K DNA, and electrophoretic mobility shift assay indicated its binding to CREM and CREB. Forskolin significantly suppressed the promoter activity in CHO-K1 cells transfected with the constructs containing B/K CLS, but not with the construct in which B/K CLS was mutated (AC：TG). Taken together, we suggest that the transcription of B/K gene in PC12 cells may be regulated by PKA-dependent mechanism.

• Journal of Ginseng Research
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• 제37권2호
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• pp.176-186
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• 2013

In this study, we have investigated the effects of total saponin from Korean red ginseng (TSKRG) on thrombin-induced platelet aggregation. TSKRG dose-dependently inhibited thrombin-induced platelet aggregation with $IC_{50}$ value of about 81.1 ${\mu}g/mL$. In addition, TSKRG dose-dependently decreased thrombin-elevated the level of cytosolic-free $Ca^{2+}$ ($[Ca^{2+}]_i$), one of aggregation-inducing molecules. Of two $Ca^{2+}$-antagonistic cyclic nucleotides as aggregation-inhibiting molecules, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), TSKRG significantly dose-dependently elevated intracellular level of cAMP, but not cGMP. In addition, TSKRG dose-dependently inhibited thrombin-elevated adenosine triphosphate (ATP) release from platelets. These results suggest that the suppression of $[Ca^{2+}]_i$ elevation, and of ATP release by TSKRG are associated with upregulation of cAMP. TSKRG elevated the phosphorylation of vasodilator-stimulated phosphoprotein (VASP)-$Ser^{157}$, a cAMP-dependent protein kinase (A-kinase) substrate, but not the phosphorylation of VASP-$Ser^{239}$, a cGMP-dependent protein kinase substrate, in thrombin-activated platelets. We demonstrate that TSKRG involves in increase of cAMP level and subsequent elevation of VASP-$Ser^{157}$ phosphorylation through A-kinase activation to inhibit $[Ca^{2+}]_i$ mobilization and ATP release in thrombin-induced platelet aggregation. These results strongly indicate that TSKRG is a beneficial herbal substance elevating cAMP level in thrombin-platelet interaction, which may result in preventing of platelet aggregation-mediated thrombotic diseases.

• 대한의생명과학회지
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• 제20권2호
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• pp.70-76
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• 2014

In this study, we investigated the effect of DMSO, a highly dipolar organic liquid, in collagen ($5{\mu}g/ml$)-stimulated platelet aggregation. DMSO inhibited platelet aggregation at 0.5% by inhibiting production of thromboxane $A_2$ ($TXA_2$) which was associated with blocking cyclooxygenase (COX)-1 activity and $TXA_2$ synthase. In addition, DMSO significantly increased the formation of cyclic adenosine monophosphate (cAMP) from adenosine triphosphate (ATP) and cyclic guanosine monophosphate (cGMP) from guanosine triphosphate (GTP). On the other hand, DMSO (0.1~0.5% concentration) did not affect the LDH release which indicates the cytotoxicity. Based on these results, DMSO has anti-platelet effect by regulation of several platelet signaling pathways, therefore we suggest that DMSO could be a novel strategy on many thrombotic disorders.