• 생명과학회지
• /
• 제30권9호
• /
• pp.826-833
• /
• 2020

Phospholipase C gamma (PLCγ)는 phosphatidylinositol을 가수분해하여 신호전달 과정에 참여하는 PLC의 주요한 isotype으로 γ-specific array의 특징적인 구조를 바탕으로 receptor tyrosine kinases 및 non-receptor tyrosine kinase 신호를 주로 매개한다. PLCγ1과 PLCγ2의 두 isozyme이 존재하며 다양한 세포에서 발현하여 cell proliferation, migration 및 differentiation 등 여러 세포작용을 조절하고 있다. 최근의 연구들에서 PLCγ 돌연변이가 cancer와 immune disease 및 brain disorder 등에 연관된다는 것이 밝혀지고 있으며 genetic model을 통해 PLCγ의 생리적·병리적 기능이 제시되었다. 본 리뷰에서는 최신의 연구 결과들을 바탕으로 PLCγ의 구조와 활성 조절 기전에 대해 기술하고 나아가 여러 질병의 발병과 진행에서 보고된 PLCγ의 돌연변이와 knockout 마우스를 활용한 연구 결과를 바탕으로 생리적·병리적 관점에서 PLCγ의 역할에 대해 고찰하였다.

• 생명과학회지
• /
• 제32권2호
• /
• pp.86-93
• /
• 2022

Lupeol은 pentacyclic triterpene의 일종으로 다양한 질병에 약리 효과가 있는 것으로 보고되어 있으나, lupeol이 포도당 흡수에 미치는 영향은 아직 보고된 바 없다. 본 연구에서 3T3-L1 지방세포에서 포도당 흡수에 대한 lupeol의 효과를 조사하였다. 그 결과, Lupeol은 3T3-L1 지방세포에서 GLUT4를 원형질막으로 이동시켜 포도당 흡수를 촉진하였으며, 이는 PI3K/AKT 및 AMPK 경로의 활성화와 관련되어 있었다. PI3K/AKT 경로에서 lupeol은 PI3K를 활성화시키는 insulin receptor substrate 1의 인산화와 AKT의 인산화를 촉진하지만 비정형 단백질 키나아제 C isoforms ζ 및 λ의 인산화는 촉진하지 않았다. 반면, lupeol은 5 'AMP-activated protein kinase의 인산화를 촉진하였고, Lupeol의 의한 AMPK의 활성화는 원형질막-GLUT4의 발현과 세포내 포도당 흡수를 증가시키는 것으로 확인되었다. 3T3-L1 지방세포에서 lupeol에 의한 포도당 흡수 효과는 PI3K 억제제인 wortmannin 및 AMPK 억제제인 Compound C에 의해 억제됨을 통해 확인하였다. 본 연구 결과는 lupeol이 3T3-L1 지방세포에서 PI3K/AKT 및 AMPK 경로를 통해 원형질막 GLUT4의 발현을 자극함으로써 인슐린 감수성을 증가시켜 포도당 흡수를 촉진할 수 있음을 제시하고 있다.

• Journal of Periodontal and Implant Science
• /
• 제41권1호
• /
• pp.17-22
• /
• 2011

Purpose: Nitric oxide (NO) has been known as an important regulator of osteoblasts and periodontal ligament cell activity. This study was performed to investigate the relationship between NO-mediated cell death of human periodontal ligament fibroblasts (PDLFs) and N-methyl-D-aspartic acid (NMDA) receptor antagonist (+)-5-methyl-10, 11-dihydro-5H-dibenzo[a,d]cyclohepten-5, 10-imine hydrogen maleate (MK801). Methods: Human PDLFs were treated with various concentrations (0 to 4 mM) of sodium nitroprusside (SNP) with or without $200\;{\mu}M$ MK801 in culture media for 16 hours and the cell medium was then removed and replaced by fresh medium containing MTS reagent for cell proliferation assay. Western blot analysis was performed to investigate the effects of SNP on the expression of Bax, cytochrome c, and caspase-3 proteins. The differences for each value among the sample groups were compared using analysis of variance with 95% confidence intervals. Results: In the case of SNP treatment, as a NO donor, cell viability was significantly decreased in a concentration-dependent manner. In addition, a synergistic effect was shown when both SNP and NMDA receptor antagonist was added to the medium. SNP treated PDLFs exhibited a round shape in culture conditions and were dramatically reduced in cell number. SNP treatment also increased levels of apoptotic marker protein, such as Bax and cytochrome c, and reduced caspase-3 in PDLFs. Mitogen-activated protein kinase signaling was activated by treatment of SNP and NMDA receptor antagonist. Conclusions: These results suggest that excessive production of NO may induce apoptosis and that NMDA receptor may modulate NO-induced apoptosis in PDLFs.

• Molecules and Cells
• /
• 제28권3호
• /
• pp.201-207
• /
• 2009

Silibinin is a polyphenolic flavonoid compound isolated from milk thistle (Silybum marianum), with known hepatoprotective, anticarcinogenic, and antioxidant effects. Herein, we show that silibinin inhibits receptor activator of $NF-{\kappa}B$ ligand (RANKL)-induced osteoclastogenesis from RAW264.7 cells as well as from bone marrow-derived monocyte/macrophage cells in a dose-dependent manner. Silibinin has no effect on the expression of RANKL or the soluble RANKL decoy receptor osteoprotegerin (OPG) in osteoblasts. However, we demonstrate that silibinin can block the activation of $NF-{\kappa}B$, c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein (MAP) kinase, and extracellular signal-regulated kinase (ERK) in osteoclast precursors in response to RANKL. Furthermore, silibinin attenuates the induction of nuclear factor of activated T cells (NFAT) c1 and osteoclast-associated receptor (OSCAR) expression during RANKL-induced osteoclastogenesis. We demonstrate that silibinin can inhibit $TNF-{\alpha}$-induced osteoclastogenesis as well as the expression of NFATc1 and OSCAR. Taken together, our results indicate that silibinin has the potential to inhibit osteoclast formation by attenuating the downstream signaling cascades associated with RANKL and $TNF-{\alpha}$.

• 대한물리치료과학회지
• /
• 제13권2호
• /
• pp.137-145
• /
• 2006

We investigated whether increased contractile responsiveness to epidermal growth factor (EGF) is associated with altered activation of mitogen-activated protein kinase (MAPK) in the aortic smooth muscle of deoxycorticosterone acetate (DOCA)-salt hypertensive rats. EGF induced contraction and MAPK activity in aortic smooth muscle strips, which were significantly increased in tissues from the DOCA-salt hypertensive rats compared with those from sham-operated rats. AG1478, PD98059, and LY294002, inhibitors of EGF receptor (EGFR) tyrosine kinase, MAPK/extracellular signal-regulated kinase (ERK) kinase, and phosphatidylinositol 3-kinase (PI3K), respectively, inhibited the contraction and the activity of ERK1/2 that were elevated by EGF. Y27632 and GF109203X, inhibitors of Rho kinase and protein kinase C, respectively, attenuated EGF-induced contraction, with no diminution of ERK1/2 activity. Although EGF also elevated the activity of EGFR tyrosine kinase in both sham-operated and DOCA-salt hypertensive rats, the expression and the magnitude of activation did not differ between strips. These results strongly suggest that EGF induces contraction by the activation of ERK1/2, which is regulated by the PI3K pathway in the aortic smooth muscle of DOCA-salt hypertensive rats.

• 대한본초학회지
• /
• 제37권5호
• /
• pp.17-26
• /
• 2022

Objective : The aim of the present study is to examine hepatic lipid-lowering and anti-inflammatory effects of silymarin combined with Jakyakgamcho-tang on non-alcoholic fatty liver disease in a high fat diet-induced obese mice model. Methods : C57BL/6 mice were divided into four dietary groups: (1) Normal, (2) Control (60% high-fat diet), (3) Control + silymarin 50 mg/kg/day (Silymarin), (4) Control + Silymarin 50 mg/kg/day + Jakyakgamcho-tang 100 mg/kg/day (SPG). After 12 weeks administration, mice were sacrificed and lipids and inflammation-related biomarkers were analyzed liver and plasma. Results : Silymarin and SPG treatments significantly lowered body and liver weights compared to the Control. Serumlipids (triglyceride (TG), total cholesterol) and pro-inflammatory cytokines (tumor necrosis factor alpha, interleukin 1𝛽, and IL-6) concentrations were significantly lowered in the Silymarin and SPG groups than the Control group. Silymarin and SPG treatments suppressed hepatic TG level and hepatic lipid droplets compared to the Control. Theses two treatments significantly increased hepatic kinase B1 and AMP-activated protein kinase protein levels, and significantly decreased hepatic key lipogenic enzymes (acetyl-CoA carboxylase, fatty acid synthase and stearyl coenzyme A desaturase 1) protein levels than the Control. SPG also significantly increased hepatic fatty acid oxidation-related protein (peroxisome proliferator-activated receptor alpha and uncoupling protein 2) levels than the Control. Conclusions: Silymarin and SPG suppressed hepatic lipid accumulation by regulating hepatic protein expression, and lowered blood pro-inflammatory cytokines concentrations though the synergic effect of silymarin and Jakyakgamchotang was not clear.

• Molecules and Cells
• /
• 제28권6호
• /
• pp.589-593
• /
• 2009

In this study, the roles of the p38 MAPK, ERK1/2 and JNK signaling pathway in IGF-I-induced AR induction and activation were examined. C2C12 cells were treated with IGF-I in the absence or presence of various inhibitors of p38 MAPK (SB203580), ERK1/2 (PD98059), and JNK (SP600125). Inhibition of the MAPK pathway with SB203580, PD98059, or SP600125 significantly decreased IGF-I-induced AR phosphorylation and total AR protein expression. IGF-I-induced nuclear fraction of total AR and phosphorylated AR were significantly inhibited by SB203580, PD98059, or SP600125. Furthermore, IGF-I-induced AR mRNA and skeletal ${\alpha}-actin$ mRNA were blocked by those inhibitors in dose-dependent manner. Confocal images showed that IGF-I-induced AR nuclear translocation from cytosol was significantly blocked by SB203580, PD98059, or SP600125, suggesting that the MAPK pathway regulates IGF-I-induced AR nuclear localization in skeletal muscle cells. The present results suggest that the MAPK pathways are required for the ligand-independent activation of AR by IGF-I in C2C12 skeletal muscle cells.

• 대한약침학회지
• /
• 제16권3호
• /
• pp.39-45
• /
• 2013

Objectives: Buxus Microphylla var. Koreana Nakai Extract (BMKNE) is used as a folk remedy for malaria and veneral disease. In the present study, we investigated the effects of BMKNE in the growth and the survival of AGS cells, the most common human gastric adenocarcinoma cell lines. Methods: The AGS cells were treated with varying concentrations of BMKNE. Analyses of the sub G1 peak, the caspase-3 and -9 activities, and the mitochondrial depolarization were conducted to determine whether AGS cell death occured by apoptosis. Also, to identify the role of transient receptor potential melastatin (TRPM) 7 channels in AGS cell growth and survival, we used human embryonic kidney (HEK) 293 cells overexpressed with TRPM7 channels. Results: Experimental results showed that the sub G1 peak, the caspase-3 and -9 activities, and the mitochondrial depolarization were increased. Therefore, BMKNE was found to induce the apoptosis of these cells, and this apoptosis was inhibited by SB203580 (a p38 mitogen-activated protein kinase (MAPK) inhibitor), and by a c-jun NH2-terminal kinase (JNK) II inhibitor. Furthermore, BMKNE inhibited TRPM7 currents and TRPM7 channel over-expressions in HEK 293 cells, exacerbating BMKNE-induced cell death. Conclusions: These findings indicate that BMKNE inhibits the growth and the survival of gastric cancer cells due to a blockade of the TRPM7 channel's activity and MAPK signaling. Therefore, BMKNE is a potential drug for treatment of gastric cancer, and both the TRPM7 channel and MAPK signaling may play an important role in survival in gastric cancer cells.

• Journal of Acupuncture Research
• /
• 제32권3호
• /
• pp.27-40
• /
• 2015

Objectives : This study was performed to evaluate the effects of water extract of Cervi Parvum Cornu(CPC), Aconiti Lateralis Radix Preparata(ALR), and Yongbu-tang(YBT) on suppression of the receptor activator of nuclear factor kappa-B ligand(RANKL)-induced osteoclast differentiation and bone resorption. Methods : The effects of CPC, ALR, YBT extracts on osteoclast differentiation were determined by culture of bone marrow macrophage(BMM). The mRNA expression levels of the nuclear factor of activated T-cells cytoplasmic 1(NFATc1), c-Fos and tartrate-resistant acid phosphatase(TRAP) in BMMs were analyzed by reverse transcriptase polymerase chain reaction(RT-PCR). Similarly, the protein expression levels of NFATc1, c-Fos, mitogen-activated protein kinase(MAPK)s and ${\beta}$-actin in cell lysates were measured by western blotting. In addition, effects of CPC, ALR and YBT extracts were determined by means of Lipopolysaccharide(LPS)-induced bone-loss with mice. Results : CPC, ALR and YBT extracts showed remarkable inhibition on RANKL-induced osteoclast differentiation without cytotoxicity. CPC and ALR extracts significantly reduced the protein expression level of NFATc1. YBT extract significantly reduced the mRNA expression levels of c-Fos, NFATc1 and the protein expression levels of c-Fos, NFATc1, AKT, p38, c-Jun N-terminal kinase(JNK). Further, YBT extract suppressed degradation of$ I-{\kappa}B$. And ALR extract significantly restored the bone erosion by LPS treatment in mice. Conclusions : YBT extract showed more remarkable inhibition on osteoclast differentiation than CPC and ALR extracts in vitro. ALR extract showed remarkable inhibition on bone resorption in vivo. Thus, YBT extract can be a useful treatment for bone-loss diseases such as osteoporosis.

• 한방비만학회지
• /
• 제20권2호
• /
• pp.109-121
• /
• 2020

Objectives: Tanshinone I is a bioactive constituent in Salvia miltiorrhiza. At present, the anti-obesity effect and mechanism of tanshinone I are not fully understood. Here we investigated the effect of tanshinone I on lipid accumulation in 3T3-L1 preadipocytes and zebrafish. Methods: Lipid accumulation and triglyceride (TG) content in 3T3-L1 cells were determined by Oil Red O staining and AdipoRed assay, respectively. The expression and phosphorylation levels of adipogenic/lipogenic proteins in 3T3-L1 cells were evaluated by Western blotting. The messenger RNA (mRNA) expression levels of adipogenic/lipogenic markers and leptin in 3T3-L1 cells were measured by reverse transcription polymerase chain reaction (RT-PCR). Lipid accumulation in zebrafish was assessed by LipidGreen2 staining. Results: Tanshinone I at 5 μM largely blocked lipid accumulation and reduced TG content in differentiating 3T3-L1 cells. Furthermore, tanshinone I decreased the expression of CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferator-activated receptor-γ (PPAR-γ), fatty acid synthase (FAS), acetyl CoA carboxylase (ACC), and perilipin A but also the phosphorylation of signal transducer and activator of transcription-3 (STAT-3) in differentiating 3T3-L1 cells. In addition, tanshinone I increased the phosphorylation of adenosine 3',5'-cyclic monophosphate (cAMP)-activated protein kinase (AMPK) while decreased the intracellular adenosine triphosphate (ATP) content with no change in the phosphorylation and expression of liver kinase-B1 in differentiating 3T3-L1 cells. Importantly, tanshinone I also reduced the extent of lipid deposit formation in developing zebrafish. Conclusions: These findings demonstrate that tanshinone I has strong anti-adipogenic effects on 3T3-L1 cells and reduces adiposity in zebrafish, and these anti-adipogenic effect in 3T3-L1 cells are mediated through control of C/EBP-α, PPAR-γ, STAT-3, FAS, ACC, perilipin A, and AMPK.