• International Journal of Oral Biology
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• 제34권2호
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• pp.115-121
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• 2009

Bone morphogenetic protein (BMP) 2 is a potent osteogenic factor. Although both Smad1/5 and mitogenactivated protein kinases (MAPKs) are activated by BMP2, the hierarchical relationship between them is unclear. In this study, we examined if BMP2-stimulated MAPK activation is regulated by Smad1/5 or vice versa. When C2C12 cells were treated with BMP2, the activation of extracellular signal-regulated kinase (ERK), p38 MAPK and c-Jun-N-terminal kinase was evident within 5 min. The knockdown of both Smad1 and Smad5 by small interfering RNA did not affect the activation of these MAPKs. In addition, neither the overexpression of Smad1 nor Smad5 induced ERK activation. When ERK activation was induced by constitutively active MEK1 expression, the protein level and activation of Smad1 increased. Furthermore, the inhibition of constitutively active BMP receptor type IB-induced ERK activation significantly suppressed Smad1 activation. These results indicate that Smad1/5 activation is not necessary for BMP2-induced MAPK activation and also that ERK positively regulates Smad1 activation.

• 대한소아치과학회지
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• 제28권2호
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• pp.238-246
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• 2001

본 실험은 탁월한 골유도능으로 관심의 대상이 되고 있는 BMP의 세포내 신호 전달자로 알려진 Smad 1과 Smad 5가 조골세포 초기 분화표지인자인 ALP 유전자의 발현에 미치는 영향 및 그 조절기전을 알아보고자 하였다. BMP 처리 없이도 Smad에 의해 ALP가 발현되는가를 알아보기 위해 Smad 1과 Smad 5가 각각 stably transfection된 C2C12 세포를 3일간 배양후 histochemical assay를 하였고, Smad 1과 Smad 5의 expression vector와 ALP promoter vector를 transient co-transfection한 후 ALP promoter activity를 측정하였다. Smad에 의한 BMP의 효과를 알아보기 위해서 100ng/ml의 BMP-2를 처리한 군과 처리하지 않은 군으로 나누어 세포를 배양한후 ALP 유전자의 발현을 northern blot analysis로 확인 하였다. Smad가 ALP 유전자의 발현을 직접적으로 조절하는가를 알아보기 위해서는 단백질 합성억제제인 cycloheximide를 전처리하여 ALP 유전자의 발현을 northern blot analysis하였다. 이상의 실험결과 다음과 같은 결론을 얻었다. $\cdot$ Smad 1과 Smad 5가 과발현된 세포에서는 BMP 처리없이도 ALP가 발현된다. $\cdot$ Smad 1과 Smad 5가 과발현된 세포에서 BMP 처리후 ALP 발현 증가율이 대조군 보다 현저히 높게 나타나 Smad가 BMP 효과를 증가시킨다는 것을 알 수 있다. $\cdot$ Smad는 새로운 단백질의 합성을 통해 ALP 유전자를 발현시킨다.

• Journal of Acupuncture Research
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• 제31권1호
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• pp.7-21
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• 2014

Objectives : To observe the regenerative effects of indirect moxibustion, a traditional Korean medical treatment on skeletal muscles using mouse model of skeletal muscle adiposity. Methods : Twenty seven ICR male mice were randomly assigned into Intact control(n=3), glycerol treatment together without moxibustion(n=12), and glycerol treatment together with moxibustion (n=12) groups. Mice of glycerol treatment groups were injected with 50 ${\mu}l$ DW(distilled water) containing 50 % of glycerol into the two tibialis anterior. After injection, moxibustion was applied at 'Shenshu'($BL_{23}$) and 'Zusanli'($ST_{36}$) acupoints three times per each session, every days for twelve days(total 12 treatments). Phospho-Erk1/2, Myostatin protein levels were analyzed by western blotting and immunofluo-rescence staining techniques for tissues of the tibialis anterior muscle. Smad, phospho-Smad were analyzed by immunofluorescence staining. Results : 1. Histological analysis of sections from injected TA muscles showed that glycerol induced rapidly muscle necrosis, with a maximum at day 3. 6 days and 9 days after injection, muscle was regenerating. 2. According to western blotting and immunofluorescence staining, phospho-Erk1/2 protein signals in glycerol treatment with moxibustion group were stronger compared to Intact and glycerol treatment without moxibustion group. 3. According to western blotting and immunofluorescence staining, myostatin protein signals in glycerol treatment without moxibustion group were stronger compared to Intact and glycerol treatment with moxibustion group. 4. According to immunofluorescence staining, Smad protein signals in glycerol treatment without moxibustion group were stronger compared to Intact and glycerol treatment with moxibustion group. 5. According to immunofluorescence staining, phospho-Smad protein signals in glycerol treatment without moxibustion group were stronger compared to Intact and glycerol treatment with moxibustion group. Conclusions : These results confirm that indirect moxibustion of 'Shenshu'($BL_{23}$) and 'Zusanli'($ST_{36}$) influences muscle regeneration in mouse models of skeletal muscle adiposity. Further discussion, and the establishment of moxibustion mechanism will prompt clinical application of moxibustion.

• IMMUNE NETWORK
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• 제12권3호
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• pp.84-88
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• 2012

B cell-activating factor belonging to the TNF family (BAFF) is primarily expressed by macrophages and stimulates B cell proliferation, differentiation, survival, and Ig production. In this study, we explored the effect of lactoferrin (LF) on BAFF expression by murine macrophages. We determined the level of BAFF expression at the transcriptional and protein levels using RT-PCR and ELISA, respectively. LF markedly enhanced BAFF expression in mouse macrophages at both the transcriptional and protein levels. Overexpression of Smad3/4 further increased LF-induced BAFF transcription while DN-Smad3 abolished the LF-induced BAFF expression. These results demonstrate that LF can enhance BAFF expression through Smad3/4 pathway.

• Molecules and Cells
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• 제40권4호
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• pp.291-298
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• 2017

MicroRNAs (miRNAs) are short non-coding RNAs that regulate genes posttranscriptionally. Past studies have reported that miR-210 is up-regulated in many cancers including cervical cancer, and plays a pleiotropic role in carcinogenesis. However, its role in regulating response towards anti-cancer agents has not been fully elucidated. We have previously reported that the natural compound 1'S-1'-acetoxychavicol acetate (ACA) is able to induce cytotoxicity in various cancer cells including cervical cancer cells. Hence, this study aims to investigate the mechanistic role of miR-210 in regulating response towards ACA in cervical cancer cells. In the present study, we found that ACA down-regulated miR-210 expression in cervical cancer cells, and suppression of miR-210 expression enhanced sensitivity towards ACA by inhibiting cell proliferation and promoting apoptosis. Western blot analysis showed increased expression of mothers against decapentaplegic homolog 4 (SMAD4), which was predicted as a target of miR-210 by target prediction programs, following treatment with ACA. Luciferase reporter assay confirmed that miR-210 binds to sequences in 3'UTR of SMAD4. Furthermore, decreased in SMAD4 protein expression was observed when miR-210 was overexpressed. Conversely, SMAD4 protein expression increased when miR-210 expression was suppressed. Lastly, we demonstrated that overexpression of SMAD4 augmented the anti-proliferative and apoptosis-inducing effects of ACA. Taken together, our results demonstrated that down-regulation of miR-210 conferred sensitivity towards ACA in cervical cancer cells by targeting SMAD4. These findings suggest that combination of miRNAs and natural compounds could provide new strategies in treating cervical cancer.

• Molecules and Cells
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• 제25권1호
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• pp.105-111
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• 2008

Radiotherapy is an important treatment for many malignant tumors, but there are recent reports that radiation may increase the malignancy of cancer cells by stimulating expression of type IV collagenases. In this study, we examined changes in matrix metalloproteinase (MMP) inhibitors, such as the tissue inhibitors of metalloproteinase (TIMP)-1, TIMP-2 and RECK, in response to irradiation in Panc-1 pancreatic cancer cells. Irradiation increased RECK protein levels but not mRNA levels, whereas no significant changes were found in TIMP-1 and TIMP-2. The enhanced RECK protein levels were associated with an increase in MMP inhibitory activity. However, irradiation slightly but reproducibly increased the invasiveness of the Panc-1 cells. Like irradiation, treatment of Panc-1 cells with transforming growth factor $(TGF)-{\beta}1$ led to a 2-fold increase in RECK protein levels. Transient transfection with Smad3 also increased RECK protein levels, but transfection with Smad7 markedly reduced them. Stable expression of Smad7 and treatment with SB431542, an inhibitor of $TGF-{\beta}$ receptor I kinase, abolished $TGF-{\beta}1$- and radiation-mediated effects on RECK. Furthermore, irradiation increased levels of phosphorylated Smad3. We conclude that radiation post-transciptionally enhances RECK protein levels in Panc-1 cells, at least in part, via $TGF-{\beta}$ signaling, and that irradiation increases Panc-1 invasiveness via a mechanism that may not be linked to MMP-2 activity.

• Journal of Nutrition and Health
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• 제51권1호
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• pp.23-30
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• 2018

Purpose: Runx2 (runt-related transcription factor 2), a bone-specific transcription factor, is a key regulator of osteoblast differentiation and its expression is induced by the activation of BMP-2 signaling. This study examined whether zinc modulates BMP-2 signaling and therefore stimulates Runx2 and osteoblast differentiation gene expression. Methods: Two osteoblastic MC3T3-E1 cell lines (subclones 4 as a high osteoblast differentiation and subclone 24 as a low osteoblastic differentiation) were cultured in an osteogenic medium (OSM) as the normal control, Zn-($1{\mu}M$ Zn) or Zn+($15{\mu}M$ Zn) for 24 h. The genes and proteins for BMP-2 signaling (BMP-2, Smad-1/p-Smad-1), transcription factors (Runx2, osterix), and osteoblast differentiation marker proteins were assessed. Results: In both cell lines, BMP-2 mRAN and protein expression and extracellular BMP-2 secretion all decreased in Zn-. The expression of Smad-1 (downstream regulator of BMP-2 signaling) and p-Smad-1 (phosphorylated Smad-1) also downregulated in Zn-. Furthermore, the expression of the bone-specific transcription factors, Runx2 and osterix, decreased in Zn-, which might be due to the decreased BMP-2 expression and Smad-1 activation (p-Smad-1) by Zn-, because Runx2 and osterix both are downstream in BMP-2 signaling. Bone marker gene expression, such as alkaline phosphatase (ALP), collagen type I (COLI), osteocalcin, and osteopontin were also downregulated in Zn-. Conclusion: The results suggest that a zinc deficiency in osteoblasts suppresses the BMP-2 signaling pathway via the suppression of Smad-1 activation, and this suppressed BMP-2 signaling can cause poor osteoblast differentiation.

• 대한한의학회지
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• 제24권2호
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• pp.1-11
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• 2003

Objectives : The aim of this study was to characterize the effect of Injinchunggan-tang on $TGF-{\beta}1-induced$ hepatic fibrosis. Methods : mRNA and protein expression levels of $TGF-{\beta}1$ in Injinchunggan-tang-treated HepG2 cells were compared to untreated cells using quantitative RT-PCR and ELISA assay, respectively. mRNA expression levels of the TGF-1 pathway genes (TR-1, TR-II, Smad2, Smad3, Smad4, and PAI-1) and fibrosis-associated genes (CTGF, fibronectin, and collagen type 1) were evaluated by quantitative RT-PCR. The effect of Injinchunggan-tang on cell proliferation of T3891 human fibroblast was evaluated using [$^3H$]thymidine incorporation assay. Results : Expression of $TGF-{\beta}1$ mRNA and protein was inhibited by Injinchunggan-tang in a dose- and time-dependent manner. Whereas $TGF-{\beta}1-mediated$ induction of PAI-1 was suppressed by Injinchunggan-tang, expression of the $TGF-{\beta}1$ pathway genes such as TR-1, TR-II, Smad2, Smad3, and Smad4 was not affected by Injinchunggan-tang treatment. Injinchunggan-tang was found to inhibit $TGF-{\beta}1-induced$ cell proliferation of T3891 human fibroblast, and also abrogated $TGF-{\beta}1-mediated$ transcriptional up-regulation of CTGF, fibronectin, and collagen type I. Conclusions : This study strongly suggests that the liver cirrhosis-suppressive activity of Injinchunggan-tang may be derived at least in part from its inhibitory effect on $TGF-{\beta}1$ functions, such as blockade of $TGF-{\beta}1$ stimulation of fibroblast cell proliferation and fibrosis-related gene expression as well as expression of $TGF-{\beta}1$ itself.

• The Korean Journal of Physiology and Pharmacology
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• 제17권5호
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• pp.447-453
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• 2013

Osteoblastic activity of nectandrin A was examined in C2C12 cells. Nectandrin A enhances the BMP-induced osteoblastic differentiation and mineralization, manifested by the up-regulation of differentiation markers (alkaline phosphatase and osteogenic genes) and increased calcium contents. In C2C12 cells co-transfected with expression vector encoding Smad4 and Id1-Luc reporter, nectandrin A increased Id1 luciferase activity in a concentration-dependent manner, when compared to that in BMP-2 treated cells, indicating that Smad signaling pathway is associated with nectandrin A-enhanced osteoblastic differentiation in C2C12 cells. In addition, nectandrin A activated p38 mitogen-activated protein kinase (MAPK) in time- and concentration-dependent manners, and phosphorylated form of pSmad1/5/8 and alkaline phosphatase activity were both decreased when the cells were pretreated with SB203580, a p38 MAPK inhibitor, suggesting that p38 MAPK might be an upstream kinase for Smad signaling pathway. Taken together, nectandrin A enhances the BMP-induced osteoblastic differentiation and mineralization of C2C12 cells via activation of p38 MAPK-Smad signaling pathway, and it has a therapeutic potential for osteoporosis by promoting bone formation.

• BMB Reports
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• 제38권1호
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• pp.9-16
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• 2005

Transforming Growth Factor (TGF)-$\beta$ family, including TGF-$\beta$, bone morphorgenic protein (BMP), and activn, plays an important role in essential cellular functions such as proliferation, differentiation, apoptosis, tissue remodeling, angiognesis, immune responses, and cell adhesions. TGF-$\beta$ predominantly transmits the signals through serine/threonine receptor kinases and cytoplasmic proteins called Smads. Since the discovery of TGF-$\beta$ in the early 1980s, the dysregulation of TGF-$\beta$/Smad signaling has been implicated in the pathogenesis of human diseases. Among signal transducers in TGF-$\beta$/Smad signaling, inhibitory Smads (I-Smads), Smad6 and Smad7, act as major negative regulators forming autoinhibitory feedback loops and mediate the cross-talking with other signaling pathways. Expressions of I-Smads are mainly regulated on the transcriptional levels and post-translational protein degradations and their intracellular levels are tightly controlled to maintain the homeostatic balances. However, abnormal levels of I-Smads in the pathological conditions elicit the altered TGF-$\beta$ signaling in cells, eventually causing TGF-$\beta$-related human diseases. Thus, exploring the molecular mechanisms about the regulations of I-Smads may provide the therapeutic clues for human diseases induced by the abnormal TGF-$\beta$ signaling.