• Title/Summary/Keyword: IL-1beta

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Vanillic Acid Stimulates Anagen Signaling via the PI3K/Akt/β-Catenin Pathway in Dermal Papilla Cells

  • Kang, Jung-Il;Choi, Youn Kyung;Koh, Young-Sang;Hyun, Jin-Won;Kang, Ji-Hoon;Lee, Kwang Sik;Lee, Chun Mong;Yoo, Eun-Sook;Kang, Hee-Kyoung
    • Biomolecules & Therapeutics
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    • v.28 no.4
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    • pp.354-360
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    • 2020
  • The hair cycle (anagen, catagen, and telogen) is regulated by the interaction between mesenchymal cells and epithelial cells in the hair follicles. The proliferation of dermal papilla cells (DPCs), mesenchymal-derived fibroblasts, has emerged as a target for the regulation of the hair cycle. Here, we show that vanillic acid, a phenolic acid from wheat bran, promotes the proliferation of DPCs via a PI3K/Akt/Wnt/β-catenin dependent mechanism. Vanillic acid promoted the proliferation of DPCs, accompanied by increased levels of cell-cycle proteins cyclin D1, CDK6, and Cdc2 p34. Vanillic acid also increased the levels of phospho(ser473)-Akt, phospho(ser780)-pRB, and phospho(thr37/46)-4EBP1 in a time-dependent manner. Wortmannin, an inhibitor of the PI3K/Akt pathway, attenuated the vanillic acid-mediated proliferation of DPCs. Vanillic acid-induced progression of the cell-cycle was also suppressed by wortmannin. Moreover, vanillic acid increased the levels of Wnt/β-catenin proteins, such as phospho(ser9)-glycogen synthase kinase-3β, phospho(ser552)-β-catenin, and phospho(ser675)-β-catenin. We found that vanillic acid increased the levels of cyclin D1 and Cox-2, which are target genes of β-catenin, and these changes were inhibited by wortmannin. To investigate whether vanillic acid affects the downregulation of β-catenin by dihydrotestosterone (DHT), implicated in the development of androgenetic alopecia, DPCs were stimulated with DHT in the presence and absence of vanillic acid for 24 h. Western blotting and confocal microscopy analyses showed that the decreased level of β-catenin after the incubation with DHT was reversed by vanillic acid. These results suggest that vanillic acid could stimulate anagen and alleviate hair loss by activating the PI3K/Akt and Wnt/β-catenin pathways in DPCs.

Human Periodontal Ligament Fibroblasts Support the Osteoclastogenesis of RAW264.7 Cells (치주인대섬유아세포가 파골세포분화에 미치는 영향)

  • Lee, Ho;Jeon, Yong-Seon;Choi, Seoung-Hwan;Kim, Hyung-Seop;Oh, Kwi-Ok
    • Journal of Periodontal and Implant Science
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    • v.32 no.4
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    • pp.733-744
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    • 2002
  • The fibroblasts are the principal cells in the periodontal ligament of peridontium. As the periodontal ligament fibroblasts (PDLF) show similar phenotype with osteoblasts, the PDLF are thought to play an important role in alveolar bone remodeling. Cell-to-cell contacted signaling is crucial for osteoclast formation. Recently it has been reported that PDLJ enhance the bone resorbing activity of osteoclasts differentiated from hematopoietic preosteoclasts. The aims of this study were to $clarify\;^{1)}$ the mechanism of PDLF-induced osteoclastogenesis $and\;^{2)}$ whether we can use preosteoclast cell line instead of primary hematopoietic preosteoclast cells for studying the mechanism of PDLF-induced osteoclastogenesis. Osteoclastic differentiation of mouse macrophage cell line RAW264.7 was compared with that of mouse bone marrow-derived M-CSF dependent cell (MDBM), a well-known hematopoietic preosteoclast model, by examining, 1) osteoclast-specific gene expression such as calcitonin receptor, M-CSF receptor (c-fms), cathepsin K, receptoractivator nuclear factor kappa B (RANK) ,2) generation of TRAP(+) multinucleated cells (MNCs), and 3) generation of resorption pit on the $OAAS^{TM}$ plate. RAW264.7 cultured in the medium containing of soluble osteoclast differentiation Factor (sODF) showed similar phenotype with MDBM-derived osteoclasts, those are mRNA expression pattern of osteoclast-specific genes, TRAP(+) MNCs generation, and bone resorbing abivity. Formation of resorption pits by osteoclastic MNCs differentiated from sODF-treated RAW264.7, was completely blocked by the addition of osteoprotegerin (OPG), a soluble decoy receptor for ODF, to the sODF-containing culture me야um. The effects of PDLF on differentiation of RAW264.7 into the TRAP(+) multinucleated osteoclast-like cells were examined using coculture system. PDLF were fxed with paraformaldehyde, followed by coculture with RAW264.7, which induced formation of TRAP(+) MNCs in the absence of additional treatment of sODF. When compared with untreated and fixed PDLF (fPDLF), IL-1 ${\beta}$-treated, or lipopolysaccha-ride-treated and then fixed PDLF showed two-folld increase in the supporting activity of osteoclastogenesis from RAW264.7 coculture system. There were no TRAP(+) MNCs formation in coculture system of RAW264.7 with PDLF of no fixation. These findigs suggested that we can replace the primary hematopoietic preosteoclasts for RAW264. 7 cell line for studying the mechanism of PDLF-induced osteoclastogenesis, and we hypothesize that PDLF control osteoclastogenesis through ODF expression which might be enhanced by inflammatory signals.

Anti-Inflammatory Effects of 1,2,3,4,6-Penta-O-Galloyl-β-D-Glucose in LPS-Stimulated Macrophages (LPS로 자극한 대식세포에서 1,2,3,4,6-Penta-O-Galloyl-β-D-Glucose의 염증 억제 효과)

  • Lee, Hee Won;Kang, Ye Rim;Bae, Min Seo;Kim, Yoon Hee
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.46 no.4
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    • pp.409-416
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    • 2017
  • 1,2,3,4,6-Penta-O-galloyl-${\beta}$-D-glucose (PGG) is a gallotannin isolated from Galla Rhois. In a previous study, PGG was shown to suppress the allergic response by attenuating immunoglobulin E production both in vitro and in vivo. However, the effect of PGG on bacteria-induced inflammation at physiological concentration remains unclear. Therefore, the aim of this study was to investigate the effect of PGG on lipopolysaccharide (LPS)-stimulated macrophages. PGG inhibited release of nitric oxide (NO) and prostaglandin $E_2$ by alleviating protein expression of inducible NO synthase and cyclooxygenase-2 in LPS-treated RAW264.7 cells. Furthermore, PGG suppressed the release of interleukin-6 and tumor necrosis factor-${\alpha}$ induced by LPS. Further study indicated that PGG blocked translocation of the p65 subunit of nuclear factor-${\kappa}B$ from the cytosol into the nucleus, which is one of the underlying mechanisms of the anti-inflammatory action of PGG. Collectively, these data suggest that PGG might be useful for the treatment of inflammatory disease.

Moxi-tar Herbal Acupuncture of BL25 Acupoint Ameliorates TNBS-Induced Colitis in Mice (TNBS로 유도된 만성 염증성 대장염에 대한 대장유(大腸兪) 구진약침(灸津藥鍼)의 효과)

  • Baek, Dae-Bong;Kwon, Oh-Sang;Choi, Won-Jong;Kim, Jae-Hyo;Jeon, Hee-Young;Kim, Kyung-Sik;Sohn, In-Chul
    • Korean Journal of Acupuncture
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    • v.24 no.3
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    • pp.149-164
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    • 2007
  • Objectives : Inflammatory bowel disease (IBD) is a chronic relapsing inflammatory disease in the gastrointestinal tract. The sources and pathologic mechanisms of IBD are still unknown. Moreover conventional therapies for IBD are not always effective, and they often have serious side effects. The purpose of this study is to examine the effect of Moxi-tar herbal acupuncture in IBD affected mice. Methods : Mice were treated with 5 % 2, 4, 6 - trinitrobenzenesulfonic acid (TNBS) on day 1 and day 7. To assume the preemptive effect and therapeutic effect, herbal acupuncture was practiced with Moxi-tar at BL25 (Daejangsu) on day 0, day 3, and day 6. The end of day in treatment with Moxi-tar herbal acupuncture, the mortality and the inflammatory factors of the colon were measured by the various methods. Results TNBS induced high mortality but herbal acupuncture with Moxi-tar at BL25 sup-pressed the mortality caused by TNBS. TNBS induced infiltration of immune cells in all layers of the colon and increased myeloperoxygenase (MPO) activity, while the treatment with Moxi-tar herbal acupuncture at BL25 suppressed the infiltration of immune cells and the increase of MPO activity caused by TNBS to normal levels, Herbal acupuncture with Moxi-tar regulated $NF-{\kappa}B$ activity, which is an important factor for the pathogenesis of chronic colitis, and reduced the expressions of $TNF-{\alpha}$, $IL-1{\beta}$, and ICAM-1 in the colons of TNBS treated mice. Furthermore herbal acupuncture suppressed macro- and micro- colonic damages caused by TNBS. Conclusions : This study demonstrates that herbal acupuncture with Moxi-tar at BL25 isa potential preemptive and/or therapeutic method targeting the chronic IBD.

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Myristoleic Acid Promotes Anagen Signaling by Autophagy through Activating Wnt/β-Catenin and ERK Pathways in Dermal Papilla Cells

  • Choi, Youn Kyung;Kang, Jung-Il;Hyun, Jin Won;Koh, Young Sang;Kang, Ji-Hoon;Hyun, Chang-Gu;Yoon, Kyung-Sup;Lee, Kwang Sik;Lee, Chun Mong;Kim, Tae Yang;Yoo, Eun-Sook;Kang, Hee-Kyoung
    • Biomolecules & Therapeutics
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    • v.29 no.2
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    • pp.211-219
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    • 2021
  • Alopecia is a distressing condition caused by the dysregulation of anagen, catagen, and telogen in the hair cycle. Dermal papilla cells (DPCs) regulate the hair cycle and play important roles in hair growth and regeneration. Myristoleic acid (MA) increases Wnt reporter activity in DPCs. However, the action mechanisms of MA on the stimulation of anagen signaling in DPCs is not known. In this study, we evaluated the effects of MA on anagen-activating signaling pathways in DPCs. MA significantly increased DPC proliferation and stimulated the G2/M phase, accompanied by increasing cyclin A, Cdc2, and cyclin B1. To elucidate the mechanism by which MA promotes DPC proliferation, we evaluated the effect of MA on autophagy and intracellular pathways. MA induced autophagosome formation by decreasing the levels of the phospho-mammalian target of rapamycin (phospho-mTOR) and increasing autophagy-related 7 (Atg7) and microtubule-associated protein 1A/1B-light chain 3II (LC3II). MA also increased the phosphorylation levels of Wnt/β-catenin proteins, such as GSK3β (Ser9) and β-catenin (Ser552 and Ser675). Treatment with XAV939, an inhibitor of the Wnt/β-catenin pathway, attenuated the MA-induced increase in β-catenin nuclear translocation. Moreover, XAV939 reduced MA-induced effects on cell cycle progression, autophagy, and DPC proliferation. On the other hand, MA increased the levels of phospho (Thr202/Tyr204)-extracellular signal regulated kinases (ERK). MA-induced ERK phosphorylation led to changes in the expression levels of Cdc2, Atg7 and LC3II, as well as DPC proliferation. Our results suggest that MA promotes anagen signaling via autophagy and cell cycle progression by activating the Wnt/β-catenin and ERK pathways in DPCs.

Effect of SAL5 on chronic ethanol-induced fatty liver model (흰쥐에서 SAL5의 알코올성 지방간 형성에 미치는 영향)

  • Kim, Bok-Kyu;Yang, Won-Kyung;Park, Yang-Chun;Jung, Ga-Young;Shin, Eun-Ju;Do, Seon-Gil;Kim, Seung-Hyung
    • The Korea Journal of Herbology
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    • v.33 no.1
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    • pp.17-26
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    • 2018
  • Objective : In this study, we investigated the effect of SAL5(mixing extracts of Schisandra chinensis Baillon, Artemisia capillaris Thunb., and Aloe vera Linne) on chronic ethanol-induced fatty liver model. Methods : Sprague-Dawley male rats were fed Liber-DeCarli (normal), ethanol liquid diet (control), SAL5 (200 mg/kg). We administrated the SAL5 on chronic ethanol-induced fatty liver model for 5 weeks. We measured alkaline phosphtase (ALP), alanine transminase (ALT), aspartate transminase (AST) and ${\gamma}-glutamyl$ transpeptase (${\gamma}-GTP$) in serum and triglyceride (TG), superoxide dismutase (SOD), catalase, glutathione (GSH) and malondialdehyde (MDA) level in liver. Liver histopathology was examined by Hematoxylin-eosin and Oil red O staining of the fixed liver tissues. Real-time PCR was performed to measure the mRNA expression of inflammatory cytokines and MMP-2, MMP-9. Results : SAL5 administration resulted in significantly decreased liver marker enzymes activities of alanine transminase (ALT), ${\gamma}-glutamyl$ transpeptase (${\gamma}-GTP$) in serum and triglyceride (TG) activities in liver. The control group decreased the activities of superoxide dismutase (SOD), catalase (CAT) with the reduced level of glutathione (GSH) in liver. On the other hand, SAL5 group increased the activities of SOD, CAT and the level of GSH. SAL5 delayed the development of an alcoholic fatty liver by reversing fat accumulation in the liver, as evidenced in histological observations. The gene expression of mRNA were significantly decreased at the $IL-1{\beta}$, $TNF-{\alpha}$, NOS-II and MMP-2 by SAL5. Conclusions : These results indicate that SAL5 might have protective effect chronic ethanol-induced fatty liver models.

Transforming growth factor $(TGF)-{\beta}1$ conjugated chitosan film for enhanced osteoblastic activity (변형성장인자가 고정된 키토산 필름의 골아세포 활성에 미치는 영향)

  • Park, Yoon-Jeong;Lee, Jue-Yeon;Kim, Kyung-Hwa;Kim, Tae-Il;Lee, Myung-Hee;Shin, Seung-Yoon;Seol, Yang-Jo;Lee, Yong-Moo;Rhyu, In-Chul;Ku, Young;Han, Soo-Boo;Min, Byung-Moo;Lee, Seung-Jin;Chung, Chong-Pyoung
    • Journal of Periodontal and Implant Science
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    • v.34 no.4
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    • pp.781-790
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    • 2004
  • 골아세포의 생물학적 기능을 증진시키기 위해 키토산의 표면개질에 대하여 연구하였다. 생체적합성 천연고분자인 키토산은 1차 아미노기를 소유하고 있으므로 적정한 공유결합제를 사용하여 세포성장인자와 같은 생리활성을 지닌 단백질을 키토산의 표면에 고정시킬 수 있다. 본 연구에서는 키토산을 필름형태로 제조하여 세포성장인자 중 형질전환성장인자를 고정하고 골아세포의 부착, 성장 및 분화를 증가시키고자 하였다. 형태전환성장인자의 고정화 효율은 단순한 흡착방법에 비해 높았으며, 표면에 형성된 공유결합은 매우 안정하였다. 골아세포를 배양하여 초기세포부착능에 대한 영향을 연구한 결과, 배양 후 4시간, 1일째, 형질전환성장인자를 고정한 키토산 표면에서 고정하지 않은 키토산의 표면에 비해 더 많은 수의 골아세포가 부착되었고, 더 많이 신장된 부착형태를 보였다. 세포활성정도와 배양 후 4주일째의 칼슘축적량을 측정한 결과, 형질전환성장인자를 고정한 키토산 표면에서 고정하지 않은 키토산의 표면에 비해 더 높았다. 위의 결과는 키토산 표면에 형태전환성장인자의 고정이 성공적으로 이루어졌으며, 또한 실제로 활성이 있는 것이 증명되었다. 위의 연구 결과에서 형질전환성장인자로 고정된 키토산은 골아세포의 초기 부착 및 분화를 촉진시켰음을 알 수 있었던 바 성장인자의 표면고정은 임플란트 및 조직공학용 지지체에도 적용하여 생체적합성과 세포기능을 증진시키는데 이용할 수 있음을 알 수 있었다.

The Evaluation of Radioimmunoassay kits for Insulin (Insulin 측정용 방사면역측정법 시약의 평가)

  • Shin, Yong Hwan;Kim, Yun Hyun;Lee, Il Kyu;Kim, Ji Young;Seok, Jae Dong;Shin, Suk Hee
    • The Korean Journal of Nuclear Medicine Technology
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    • v.16 no.2
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    • pp.149-155
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    • 2012
  • Purpose : Serum insulin levels are useful indicator which of reflecting the function of insulin secretion in pancreatic ${\beta}$ cell and diagnosis of diabetes, differentiating the cause of impaired glucose tolerance. Insulin measurement kits have shown some differences in many ways such as test methods as well as quality control. The purpose of this study was to evaluate the diagnostic performance of seven manufacturing companies commercial kits. Materials and Methods : The values of insulin measured by three manufacturing companies (Biosource, Siemens, TFB) with 59 samples in August 2009 were compared with those measured by four manufacturing companies (Immunotech, Izotope, BNIBT, Cisbio) with 68 samples in December 2011. We evaluated precision, recovery rate, dilution test and correlation of serum insulin measurement using seven manufacturing company kits. Statistical program SPSS 12.0 was used for the verification of results. Results : The coefficients variation of the precision on all seven different kits were showed within 5.0%. Recovery rate of Biosource, Siemens, TFB kits on three different levels showed 94.2~103.7%, 99.0~104.6%, 99.7~107.6% respectively. Immunotech, Izotope, BNIBT, Cisbio were 93.5~99.1%, 91.4~99.1%, 99.2~131.0%, 84.8~102.3% respectively. There was strong correlation between the measurement of insulin by Biosource kit and that by two commercial kits, Siemens (R2=0.96), TFB (R2=0.99). There was good correlation between the measurement of insulin by TFB kit and that by three commercial kits, Immunotech (R2=0.97), Izotope (R2=0.96), Cisbio (R2=0.97). In the dilution test performed with more than 200 ${\mu}IU/ml$ high concentration samples, samples with diabetes correctly was measured in all seven manufacturing kits. However, as measured with insulinoma samples TFB, Siemens, Izotope, Cisbio kits were correctly measured, but Biosource and Immunotech kits were measured 47.4 ${\mu}IU/ml$, 72.3 ${\mu}IU/ml$, respectively. Conclusion : Serum Insulin radioimmunoassay kits were showed excellent precision, correlation and good recovery rate. However, some kits were not measured correctly in the high concentration insulin values. when selecting a kit should be considered many factors that cost effectiveness, compatible for automation equipment, high performance kit, the environment for each laboratory such as reaction time and reporting time.

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Anti-inflammatory Metabolites of Agrimonia pilosa Ledeb. and Their Mechanism

  • Park, Mi Jin;Ryu, Da Hye;Cho, Jwa Yeoung;Kang, Young-Hwa
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2018.04a
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    • pp.13-13
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    • 2018
  • The anti-inflammatory (INF) compounds (1-15) were isolated from Agrimonia pilosa Ledeb. (APL) by activity-guided isolation technique. The isolated compounds (1-15) were identified as quercetin-7-O-rhanmoside (1), apigenin-7-O-glycoside (2), kaempferol-7-O-glycoside (3), apigenin-7-O-[6"-(butyl)-glycoside] (4), querceitn (5), kaempferol (6), apigenin (7), apigenin-7-O-[6"-(pentyl)-glycoside] (8), agrimonolide (9), agrimonolide-6-O-glucoside (10), desmethylagrimonolide (11), desmethylagrimonolide-6-O-glucoside (12), luteolin (13), vitexin (14) and isovitexin (15). Flavonoids, compound 2, 3, 11, and 14-15 have been found in APL for the first time. Furthermore, two novel flavone derivatives, compound 4 and 8, have been isolated inceptively in plant. In the no cytotoxicity concentration ranges of $0-20{\mu}M$, nitric oxide (NO) production level of 1-15 was estimated in LPS-treated Raw 264.7 macrophage cells. The flavone aglycones, 7 (apigenin, $IC_{50}=3.69{\pm}0.34{\mu}M$), 13 (luteolin, $IC_{50}=4.62{\pm}0.43{\mu}M$), 6 (kaempferol, $IC_{50}=14.43{\pm}0.23{\mu}M$) and 5 (quercetin, $IC_{50}=19.50{\pm}1.71{\mu}M$), exhibited excellent NO inhibitory (NOI) activity in dose-dependent manner. In the structure activity relationship (SAR) study of apigenin-derivatives (APD), apigenin; Api, apigenin-7-O-glucoside; Api-G, apignenin-7-O-[6"-(butyl)-glycoside]; Api-BG and apignenin-7-O-[6"-(pentyl)-glycoside]; Api-P, from APL on INF activity was investigated. The INF mediators level such as NO, INF-cytokines, NF-KB proteins, iNOS and COX-2 were sharply increased in Raw 264.7 cells by LPS. When pretreatment with APD in INF induced macrophages, NOI activity of Api was most effective than other APD with $IC_{50}$ values of $3.69{\pm}0.77{\mu}M$. And the NOI activity was declined in the following order: Api-BG ($IC_{50}=8.91{\pm}1.18{\mu}M$), Api-PG ($IC_{50}=13.52{\pm}0.85{\mu}M$) and API-G ($IC_{50}=17.30{\pm}0.66{\mu}M$). The NOI activity of two novel compounds, Api-PG and Api-BG were lower than their aglycone; Api, but more effective than Api-G (NOI: Api-PG and Api-BG). And their suppression ability on INF cytokines such as $TNF-{\alpha}$, $IL-1{\beta}$ and IL-6 mRNA showed the similar tendency. Therefore, the anti-INF mechanism study of Api-PG and Api-BG on nuclear factor-kappa B ($NF-{\kappa}B$) pathway, representative INF mechanism, was investigated and Api was used as positive control. Api-BF was more effectively prevent the than phosphorylation of $pI{\kappa}B$ kinase (p-IKK) and p65 than Api-PG in Raw 264.7 cells. In contrast, Api-PG and Api-BG were not reduced the phosphorylation of inhibitor of kappa B alpha ($I{\kappa}B{\alpha}$). Moreover, pretreatment with Api-PG and Api-BG, dose-dependently inhibited LPS-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNAs and proteins in macrophage cells, and their expression were correlated with their NOI activity. Therefore, APL can be utilized to health promote agent associated with their AIN metabolites.

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Overexpression of TMP21 Could Induce not only Downregulation of TrkA/ERK Phosphorylation but also Upregulation of p75NTR/RhoA Expression on NGF Receptor Signaling Pathway (γ-Secretase 활성억제단백질인 TMP21의 과발현이 신경세포주에서 NGF 수용체 신호전달과정에 미치는 영향)

  • Choi, Sun-Il;Jee, Seung-Wan;Her, Youn-Kyung;Kim, Ji-Eun;Nam, So-Hee;Hwang, In-Sik;Lee, Hye-Ryun;Goo, Jun-Seo;Lee, Young-Ju;Lee, Eon-Pil;Choi, Hae-Wook;Kim, Hong-Sung;Lee, Jae-Ho;Jung, Young-Jin;Lee, Su-Hae;Shim, Sun-Bo;Hwang, Dae-Youn
    • Journal of Life Science
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    • v.21 no.8
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    • pp.1134-1141
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    • 2011
  • Transmembrane protein 21 (TMP21) is a member of the p24 cargo protein family and has been shown to modulate ${\alpha}$-secretase-mediated A${\beta}$ production which was specifically observed in the brains of subjects with Alzheimer's disease (AD). In order to investigate whether TMP21 could affect nerve growth factor (NGF) receptor signaling pathway, the alteration of NGF receptors and their downstream proteins were detected in TMP21 over-expressed cells. CMV/hTMP21 vector used in this study was successfully expressed into TMP21 proteins in B35 cells after lipofectamin transfection. Expressed TMP21 proteins induced the down-regulation of ${\gamma}$-secretase complex components including Presenlin-1 (PS-1), PS-2, Nicastrin (NST), Pen-2 and APH-1. Also, the expression level of NGF receptor $p75^{NTR}$ and RhoA were significantly higher in CMV/hTMP21 transfectants than vehicle transfectants, while their levels returned to vehicle levels after NGF treatment. However, the phosphorylation of NGF receptor TrkA was dramtically decreased in NGF No-treated CMV/hTMP21 transfectants compared with vehicle transfectants, and increased in NGF treated CMV/hTMP21 transfectants. In TrkA downstream signaling pathway, the phosphorylation level of ERK was also decreased in CMV/hTMP21 transfectants, while the phosphorylation of Akt was increased in the same transfectants. Furthermore, NGF treatment induced the increase of phosphorylation level of Akt and ERK in CMV/hTMP21 transfectants. Therefore, these results suggested that over-expression of TMP21may simultaneously induce the up-regulation of $p75^{NTR}$/RhoA expression and the down-regulation of TrkA/ERK phosphorylation through the inhibition of ${\gamma}$-secretase activity.