• Genomics & Informatics
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• 제9권4호
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• pp.161-172
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• 2011

Angiogenesis is regulated by a large number of molecules and complex signaling mechanisms. The G protein $G{\alpha}_{13}$ is a part of this signaling mechanism as an endothelial cell movement regulator. Gene expression analysis of $G{\alpha}_{13}$ knockout mouse embryos was carried out to identify the role of $G{\alpha}_{13}$ in angiogenesis signaling during embryonic development. Hypoxia-inducible response factors including those acting as regulators of angiogenesis were over expressed, while genes related to the cell cycle, DNA replication, protein modification and cell-cell dissociation were under expressed. Functional annotation and network analysis indicate that $G{\alpha}_{13}{^{-/-}}$ embryonic mice were exposed to hypoxic conditions. The present analysis of the time course highlighted the significantly high levels of disorder in the development of the cardiovascular system. The data suggested that hypoxia-inducible factors including those associated with angiogenesis and abnormalities related to endothelial cell division contributed to the developmental failure of $G{\alpha}_{13}$ knockout mouse embryos.

• Molecules and Cells
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• 제41권5호
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• pp.454-464
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• 2018

Crosstalk between G-protein signaling and glutamatergic transmission within the brain reward circuits is critical for long-term emotional effects (depression and anxiety), cravings, and negative withdrawal symptoms associated with opioid addiction. A previous study showed that Regulator of G-protein signaling 4 (RGS4) may be implicated in opiate action in the nucleus accumbens (NAc). However, the mechanism of the NAc-specific RGS4 actions that induce the behavioral responses to opiates remains largely unknown. The present study used a short hairpin RNA (shRNA)-mediated knock-down of RGS4 in the NAc of the mouse brain to investigate the relationship between the activation of ionotropic glutamate receptors and RGS4 in the NAc during morphine reward. Additionally, the shRNA-mediated RGS4 knock-down was implemented in NAc/striatal primary-cultured neurons to investigate the role that striatal neurons have in the morphine-induced activation of ionotropic glutamate receptors. The results of this study show that the NAc-specific knock-down of RGS4 significantly increased the behaviors associated with morphine and did so by phosphorylation of the GluR1 (Ser831) and NR2A (Tyr1325) glutamate receptors in the NAc. Furthermore, the knock-down of RGS4 enhanced the phosphorylation of the GluR1 and NR2A glutamate receptors in the primary NAc/striatal neurons during spontaneous morphine withdrawal. These findings show a novel molecular mechanism of RGS4 in glutamatergic transmission that underlies the negative symptoms associated with morphine administration.

• Asian Pacific Journal of Cancer Prevention
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• 제13권4호
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• pp.1097-1104
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• 2012

Background/Aim: Pristimerin isolated from Celastrus and Maytenus spp can inhibit proteasome activity. However, whether pristimerin can modulate cancer metastasis is unknown. Methods: The impacts of pristimerin on the purified and intracellular chymotrypsin proteasomal activity, the levels of regulator of G protein signaling 4 (RGS 4) expression and breast cancer cell lamellipodia formation, and the migration and invasion were determined by enzymatic, Western blot, immunofluorescent, and transwell assays, respectively. Results: We found that pristimerin inhibited human chymotrypsin proteasomal activity in MDA-MB-231 cells in a dose-dependent manner. Pristimerin also inhibited breast cancer cell lamellipodia formation, migration, and invasion in vitro by up-regulating RGS4 expression. Thus, knockdown of RGS4 attenuated pristimerin-mediated inhibition of breast cancer cell migration and invasion. Furthermore, pristimerin inhibited growth and invasion of implanted breast tumors in mice. Conclusion: Pristmerin inhibits proteasomal activity and increases the levels of RGS4, inhibiting the migration and invasion of breast cancer cells.

• 생명과학회지
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• 제19권11호
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• pp.1506-1513
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• 2009

RGS단백질은 G 단백질 신호전달작용에 있어서 신호를 억제하는 조절단백질로서 G 단백질 매개수용체(GPCR)의 활성을 억제하는 것으로 알려졌다. 그렇지만 캐너비노이드 수용체 CB2의 활성에 있어서 RGS 단백질의 조절효과에 관해서는 지금까지 알려져 있지 않다. 그러므로 본 연구에서 우리는 RGS2, 3, 4, 5와 캐너비노이드 수용체 CB2 cDNA를 동시에 HEK293 세포주에 발현시킨 후 각 RGS 단백질의 효과를 조사하였다. CB2 단백질을 발현하는 HEK293 세포주(CB2-HEK293)에서 CB2 효현제인 WIN55,212-2는 폴스콜린으로 유도된 cAMP response element (CRE) 활성을 억제하였다. 이러한 WIN55,212-2의 CRE 억제 활성은 RGS3에 의하여 차단되었지만 RGS2, 4, 및 RGS5에서는 관찰되지 않았다. 뿐만 아니라 RGS3 small interference RNA (siRNA)를 사용하여 내인성 RGS3 단백질의 발현을 저하시키면 WIN55,212-2에 의한 폴스콜린 유도 CRE 억제활성은 더욱 증강되었다. 이상의 결과는 캐너비노이드 수용체 CB2 신호전달작용에 있어서 RGS 단백질의 기능적 역할과 특히 내인성 RGS3의 캐너비노이드 수용체 CB2에 대한 선택적 작용을 나타낸다.

• Natural Product Sciences
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• 제16권4호
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• pp.239-244
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• 2010

Protein tyrosine phosphatase 1B (PTP1B), a negative regulator of insulin signaling, has served as a potential drug target for the treatment of type 2 diabetes. The MeOH extracts of twenty-nine medicinal plants, traditionally used in Vietnam as anti-diabetes agents, were investigated for PTP1B inhibitory activity in vitro. The results indicated that, most materials showed moderate to strong inhibitory activity with $IC_{50}$ values ranging from $3.4\;{\mu}g/mL$ to $35.1\;{\mu}g/mL$; meanwhile, eleven extracts (37.9%) could demonstrate PTP1B activity with $IC_{50}$ values less than $15.5\;{\mu}g/mL$; sixteen extracts (55.2%) could demonstrate PTP1B activity with $IC_{50}$ values ranging from $15.5\;{\mu}g/mL$ to $35.1\;{\mu}g/mL$. The study may provide a proof, at least in a part, for the ethno-medical use in diabetes disease of these plants.

• 한국해양바이오학회지
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• 제2권4호
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• pp.230-233
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• 2007

Protein tyrosine phosphatase 1B (PTP1B) acts as a negative regulator of insulin signaling, and selective inhibition of PTP1B has served as a potential drug target for the treatment of type 2 diabetes. As part of our searching for PTP1B inhibitors from natural products, the extracts of marine microorganisms were screened for the inhibitory effects on the activity of protein tyrosine phosphatase 1B (PTP1B). Among the tested 304 extracts, 29 extracts exhibited inhibition rate ranging 40.1 - 83.6 % against PTP1B at the concentration level of $30{\mu}g/mL$.

• BMB Reports
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• 제47권6호
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• pp.324-329
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• 2014

Regulators of G-protein signaling (RGS) proteins regulate certain G-protein-coupled receptor (GPCR)-mediated signaling pathways. The GABAB receptor ($GABA_BR$) is a GPCR that plays a role in the stress response. Previous studies indicate that acute immobilization stress (AIS) decreases RGS4 in the prefrontal cortex (PFC) and hypothalamus (HY) and suggest the possibility of a signal complex composed of RGS4 and $GABA_BR$. Therefore, in the present study, we tested whether RGS4 associates with $GABA_BR$ in these brain regions. We found the co-localization of RGS4 and $GABA_BR$ subtypes in the PFC and HY using double immunohistochemistry and confirmed a direct association between $GABA_{B2}R$ and RGS4 proteins using co-immunoprecipitation. Furthermore, we found that AIS decreased the amount of RGS4 bound to $GABA_{B2}R$ and the number of double-positive cells. These results indicate that $GABA_BR$ forms a signal complex with RGS4 and suggests that RGS4 is a regulator of $GABA_BR$.

• 한국환경성돌연변이발암원학회지
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• 제25권3호
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• pp.87-96
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• 2005

[ $p16^{INK4a}$ ] is a tumor suppressor that belongs to the INK4 family of the cyclin D-dependent kinases (cdk) inhibitors. It plays regulatory roles in cell proliferation and in tumorigenesis by interacting with Rb signaling. Abnormally elevated $p16^{INK4a}$ protein expression causes cell cycle arrest (G1/S transition) and loss of cyclin-cdk activity. In many cancers, $p16^{INK4a}$ is altered by mutation, deletion, and promoter methylation. This review summarizes the function of p16 as an important regulator of cancer pathobiology and a promising target fer developing cancer therapeutic and chemopreventive agents.

• Journal of Microbiology and Biotechnology
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• 제30권1호
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• pp.38-43
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• 2020

Hand, foot, and mouth disease (HFMD) is caused by enterovirus 71 (EV71) in infants and children under six years of age. HFMD is characterized by fever, mouth ulcers, and vesicular rashes on the palms and feet. EV71 also causes severe neurological manifestations, such as brainstem encephalitis and aseptic meningitis. Recently, frequent outbreaks of EV71 have occurred in the Asia-Pacific region, but currently, no effective antiviral drugs have been developed to treat the disease. In this study, we investigated the antiviral effect of salvianolic acid B (SalB) on EV71. SalB is a major component of the Salvia miltiorrhiza root and has been shown to be an effective treatment for subarachnoid hemorrhages and myocardial infarctions. HeLa cells were cultured in 12-well plates and treated with SalB (100 or 10 ㎍/ml) and 10⁶ PFU/ml of EV71. SalB treatment (100 ㎍/ml) significantly decreased the cleavage of the eukaryotic eIF4G1 protein and reduced the expression of the EV71 capsid protein VP1. In addition, SalB treatment showed a dramatic decrease in viral infection, measured by immunofluorescence staining. The Akt signaling pathway, a key component of cell survival and proliferation, was significantly increased in EV71-infected HeLa cells treated with 100 ㎍/ml SalB. RT-PCR results showed that the mRNA for anti-apoptotic protein Bcl-2 and the cell cycle regulator Cyclin-D1 were significantly increased by SalB treatment. These results indicate that SalB activates Akt/PKB signaling and inhibits apoptosis in infected HeLa cells. Taken together, these results suggest that SalB could be used to develop a new therapeutic drug for EV71-induced HFMD.

• 생명과학회지
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• 제29권5호
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• pp.514-523
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• 2019

인삼(Panax ginseng C. A. Meyer)의 사포닌 진세노사이드 Rb1이 처리된 인간 피부각질세포 HaCaT에서 microarray 분석 및 발현이 증가된 세포사멸 반응에 대한 작용기전을 연구하였다. HaCaT 세포에 진세노사이드 Rb1의 처리로 세포사멸, 유사분열 세포주기의 G2/M 전이, 세포분열, 핵분열, 그리고 단백질 수송 등의 작용기전에 관여하는 유전자들이 2 배 이상 발현이 증가된 것으로 나타났으며, DNA 수선, 감수 핵분열, 그리고 세포외기질 체계 등의 작용기전에 관여하는 유전자들은 2 배 이상 발현이 감소된 것으로 나타났다. 특히 세포사멸 신호전달은 FAS와 PLA2G4A를 경유하는 것으로 나타났으며, 이들 유전자의 상위 조절자로 STAT3가 예측되었다. 세포사멸 반응 경유 유전자 FAS와 PLA2G4A의 활성을 qPCR로 확인한 결과, FAS 유전자는 $10{\mu}g/ml$의 진세노사이드 Rb1를 24시간 동안 처리하였을 경우 약 2 배의 발현 증가와, PLA2G4A 유전자는 6시간 처리부터 약 2 배로 증가되어 24시간 동안 처리시 2 배 이상의 유전자 발현이 증가되었다. 한편 STAT3-siRNA를 이용한 knock-down 실험에서 FAS의 발현 감소와 PLA2G4A의 발현 증가로 상위 조절자 STAT3로부터 FAS 만을 경유하는 것을 알 수 있었다. 이상의 결과 진세노사이드 Rb1의 처리에 의해 상위 조절자인 STAT3는 FAS를 경유하여 세포사멸을 유도하는 것임을 알 수 있다.