• 한국균학회지
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• 제46권2호
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• pp.161-176
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• 2018

진균류 유래의 ${\beta}$-glucan은 pathogen-associated molecular patterns의 일종이기도 하며 면역촉진과 항암작용을 나타냄이 알려져 있지만 세포 내 신호전달에 관해서는 알려진 바가 많지 않다. 대식세포주인 RAW264.7 세포에 불로초에서 추출한 ${\beta}$-glucan을 처리하였을 때 세포막에서는 덱틴-1, toll-like receptor 2, 4, 6의 발현이 증가되었으며, 세포 내에서는 macrophage inflammatory protein (MIP)-1a, MIP-$1{\beta}$, MIP-$1{\gamma}$, IL-$1{\beta}$ 그리고 tumor necrosis factor (TNF)-${\alpha}$의 발현이 증가되었다. 또한 대식세포주에 불로초의 ${\beta}$-glucan과 PI3K 또는 MEK1/MEK2 억제제를 각각 처리하였을 때에 세포 내의 MIP-1a, MIP-$1{\beta}$, MIP-$1{\gamma}$, interleukin-$1{\beta}$, TNF-${\alpha}$의 발현이 감소되었다. 따라서 불로초의 ${\beta}$-glucan은 대식세포에서 MyD88의 경로인 PI3K/Akt를 경유할 뿐만 아니라 MEK 경로를 활성화시킴으로써 다양한 면역조절작용이 가능한 것으로 여겨진다.

• IMMUNE NETWORK
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• 제5권4호
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• pp.237-246
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• 2005

Background: Little information is available on the identification and characterization of the upstream regulators of the signal transduction cascades for Mycobacterium tuberculosis (M. tbc)-induced ERK 1/2 activation and chemokine expression. We investigated the signaling mechanisms involved in expression of CCL3 /MIP-1 and CCL4/MIP-1 in human primary monocytes infected with M. tbc. Methods: MAP kinase phosphorylation was determined using western blot analysis with specific primary antibodies (ERK 1/2, and phospho-ERK1/2), and the upstream signaling pathways were further investigated using specific inhibitors. Results: An avirulent strain, M. tbc H37Ra, induced greater and more sustained ERK 1/2 phosphorylation, and higher CCL3 and CCL4 production, than did M. tbc H37Rv. Specific inhibitors for mitogen-activated protein kinase (MAPK) kinase (MEK; U0126 and PD98059) significantly inhibited the expression of CCL3 and CCL4 in human monocytes. Mycobactetia-mediated expression of CCL3 and CCL4 was not inhibited by the Ras inhibitor manumycin A or the Raf-1 inhibitor GW 5074. On the other hand, phospholipase C (PLC) inhibitor (U73122) and protein kinase C (PKC)specific inhibitors ($G\ddot{o}6976$ and Ro31-8220) significantly reduced M. tbc-induced activation of ERK 1/2 and chemokine synthesis. Conclusion: These results are the first to demonstrate that the PLC-PKC-MEK-ERK, not the Ras-Raf-MEK-ERK, pathway is the major signaling pathway inducing M. tbc-mediated CCL3 and CCL4 expression in human primary monocytes.

• Advances in Traditional Medicine
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• 제10권4호
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• pp.254-262
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• 2010

Artemisia capillaris (A. capillaries) is known to play roles in many cellular events, such as cell proliferation, differentiation, and apoptosis. We investigated the antifibrogenic efficacy of A. capillaris in the immortalized human hepatic stellate cell line LX2. Cell proliferation was determined by the MTT assay. Cell cycle was analyzed by the flow cytometry. Apoptotic cells were measured using a cell death detection ELISA. Caspase activity was detected by a colorimetric assay. The mRNA level of Bcl-2 and Bax mRNA were measured by real-time PCR. MEK and ERK protein were detected by Western blot analysis. We provide evidence that A. capillaris induces cell cycle arrest, apoptosis, and potently inhibits the mitogen-activated protein kinase pathway. A. capillaris inhibited cell proliferation of LX2 cells in a dose- and time-dependent manner, increased the apoptosis fraction at cell cycle analysis with an accompanying DNA fragmentation, and resulted in a significant decrease in Bcl-2 mRNA levels and an increase in Bax expression. Exposure of LX2 cells to A. capillaris induced caspase-3 activation, but co-treatment of A. capillaris with the pan-caspase inhibitor Z-VAD-FMK, and the caspase-3 inhibitor Z-DEVE-FMK, blocked apoptosis. A. capillaris down-regulated Mcl-1 protein levels and inhibited phosphorylation of MEK/ERK, suggesting that it mediates cell death in LX2 cells through the down-regulation of Mcl-1 protein via a MEK/ERK-independent pathway.

• 생명과학회지
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• 제32권6호
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• pp.421-429
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• 2022

본 연구에서는 죽상경화 플락에서 발견되는 펩티도글리칸이 혈관염증에서 어떠한 역할을 하는지 알아보기 위하여 염증성 사이토카인의 한 종류인 인터루킨-1 알파의 발현에 대한 영향을 조사하였다. 실험방법으로는 혈관염증을 주도하는 단핵구/대식세포인 THP-1 세포주에 펩티도글리칸을 처리하고 인터루킨-1 알파의 발현을 RT-PCR, real-time PCR, ELISA 방법으로 분석하였다. 펩티도글리칸의 처리 시간과 농도에 비례하여 단핵구/대식세포에서 인터루킨-1 알파의 전사체와 단백질 분비가 증가함을 관찰하였다. 또한 펩티도글리칸의 작용기전을 규명하기 위하여 신호전달을 차단하는 억제제를 세포에 처리하고 인터루킨-1 알파의 발현을 조사하였다. TLR2/4의 억제제인 OxPAPC 그리고 세포 kinase의 작용을 억제하는 LY294002(PI3 kinase 억제), Akti IV (Akt 억제), rapamycin (mTOR 억제), U0126 (MEK 억제), SB202190 (p38 MAPK 억제), SP6001250 (JNK 억제), DPI (NOX 억제)를 처리하는 경우 인터루킨-1 알파 전사체의 발현 그리고 단백질의 분비가 감소되었다. 반면에 LPS의 작용을 억제하는 polymyxin B는 인터루킨-1 알파의 발현에 영향을 주지 않았다. 이상의 결과는, 펩티도글리칸이 TLR2, PI3K, Akt, mTOR, MAPKs를 통하여 단핵구/대식세포의 인터루킨-1 알파 발현을 증가시키고 혈관염증에 기여한다는 것을 나타낸다.

• Nutrition Research and Practice
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• 제4권4호
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• pp.276-282
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• 2010

The principal objective of this study was to evaluate the chemopreventive and therapeutic effects of a combination of all-trans-retinoic acid (RA) and knockdown of delta-like 1 homologue (Drosophila) (DLK1) on neuroblastoma, the most common malignant disease in children. As unfavorable neuroblastoma is poorly differentiated, neuroblastoma cell was induced differentiation by RA or DLK1 knockdown. Neuroblastoma cells showed elongated neurite growth, a hallmark of neuronal differentiation at various doses of RA, as well as by DLK1 knockdown. In order to determine whether or not a combination of RA and DLK1 knockdown exerts a greater chemotherapeutic effect on neuroblastoma, cells were incubated at 10 nM RA after being transfected with SiRNA-DLK1. Neuronal differentiation was increased more by a combination of RA and DLK1 knockdown than by single treatment. Additionally, in order to assess the signal pathway of neuroblastoma differentiation induced by RA and DLK1 knockdown, treatment with the specific MEK/ERK inhibitors, U0126 and PD 98059, was applied to differentiated neuroblastoma cells. Differentiation induced by RA and DLK1 knockdown increased ERK phosphorylation. The MEK/ERK inhibitor U0126 completely inhibited neuronal differentiation induced by both RA and DLK1 knockdown, whereas PD98059 partially blocked neuronal differentiation. After the withdrawal of inhibitors, cellular differentiation was fully recovered. This study is, to the best of our knowledge, the first to demonstrate that the specific inhibitors of the MEK/ERK pathway, U0126 and PD98059, exert differential effects on the ERK phosphorylation induced by RA or DLK1 knockdown. Based on the observations of this study, it can be concluded that a combination of RA and DLK1 knockdown increases neuronal differentiation for the control of the malignant growth of human neuroblastomas, and also that both MEK1 and MEK2 are required for the differentiation induced by RA and DLK1 knockdown.

• 생명과학회지
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• 제19권10호
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• pp.1438-1443
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• 2009

이 연구는 신장섬유아 세포를 이용하여 LPS에 의해 유도된 신장섬유화 표적유전자인 plasminogen activator inhibitor (PAI-1) 발현과 Ascofuranone (AF)에 의한 신장섬유화 저해효과를 연구하였다. 이 연구를 통해 LPS가 PAI-1의 발현을 농도 및 시간 의존적으로 증가시켜 LPS가 신장섬유화 유도물질임을 확인 할 수 있었다. 또한 LPS로 유도된 PAI-1 mRNA 및 단백질 발현 레벨이 AF에 의해 저해되었으며, 신장섬유화의 또 다른 대표유전자인 fibronectin의 단백질 발현도 AF에 의해 억제되어 AF가 신장섬유화를 저해하는 사실을 확인할 수 있었다. 그리고 AF에 대한 PAI-1 프로모터 활성을 조사하기 위하여 p800-PAI-1-luc을 신장섬유아 세포에 형질전환 시킨 결과, AF가 PAI-1의 전사 활성 조절을 통해 발현을 억제한다는 것을 확인하였다. ERK-1/2의 상위에 존재하는 MEK inhibitor를 처리하여 PAI-1의 발현을 확인한 결과에서도 AF를 처리한 경우와 동일하게 PAI-1 발현이 저해되어 LPS로 유도된 PAI-1의 발현이 ERK-1/2에 의해 조절됨을 알 수 있었다. 또한 LPS로 유도된 ERK-1/2의 인산화가 AF 농도의존적으로 저해된 결과는, AF가 ERK-1/2의 활성저해를 통하여 PAI-1 발현을 조절한다는 사실을 확인 할 수 있었다. 따라서 이러한 연구결과 AF가 신장섬유화를 저해하는 유력한 후보물질로서의 가능성을 제시하였다.

• 대한한의학회지
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• 제21권4호
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• pp.64-72
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• 2000

Objectives : This study was designed to investigate the neuroprotective effect of Hwansodan(Huanshao-dan) on the apoptosis induced by withdrawal of neurotrophic support. Methods : PCl2 pheochromocytoma cells have been used extensively as a model for studying the cellular and molecular effects of neuronal cells. The viability of cells was measured by MTT assay. We used DNA fragmentation and caspase 3-like protease activation assay. Results : The water extract of Hwansodan(Huanshao-dan) significantly showed protective effects on serum and glucose deprivation-induced apoptotic death. Hwansodan(Huanshao-dan) also prevents DNA fragmentation and caspase 3-like protease activation, representing typical neuronal apoptotic phenomena in PCl2 pheochromocytoma cells and induces tyrosine phosphorylation of proteins around 44 kDa, which was identified as ERK1 with electrophoretic gel mobility shift by Western blot. In addition, MAPK kinase(MEK) inhibitor PD98059 and Ras inactivator, ${\alpha}-hydroxyfarnesylphosphonic$ acid attenuated the neuroprotective effects of Hwansodan(Huanshao-dan) in serum-deprived PCl2 cells. Conclusions : These results indicate that Ras/MEK/ERK signaling pathway plays a key role in neuroprotective effects of Hwansodan(Huanshao-dan) in serum-deprived PCl2 cells. Taken together, we suggest the possibility that Hwansodan(Huanshao-dan) might provide a neurotrophic-like activity in PCl2 cells.

• 한국발생생물학회지:발생과생식
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• 제13권4호
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• pp.291-296
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• 2009

멍게 유생의 뇌포에는 2개의 감각색소세포인 평형기와 안점 이외에 또 다른 감각세포로 추정되는 수압수용체세포가 존재한다. 수압수용체세포 형성에 관해서는 현재까지 거의 알려진 것이 없다. 본 연구에서는 수압수용체세포 형성에서 FGF 신호전달 과정의 관련성을 조사했다. 수정란에 Hr-FGF9/16/20 antisense MO를 미세주입했을 때, 발생한 유생에서 수압수용체세포 특이적 Hpr-1 항원의 발현이 검출되지 않았다. 32세포기부터 FGF 수용체 억제제 SU5402 및 MEK 억제제 U0126을 처리한 배아도 수압수용체세포를 갖지 못한 유생으로 발생했다. 다음으로 수압수용체세포 형성에 FGF 신호전달 과정이 관련되는 시기를 자세히 조사했다. 수압수용체세포 형성에는 FGF 수용체 활성이 16세포기부터 64세포기까지 필요하다는 것이 시사되었다. U0126은 8세포기부터 후기 낭배기까지 Hpr-1 항원 발현을 억제했다. Hpr-1 항원 발현은 신경판기 직전부터 U0126의 영향을 받지 않았다. 따라서, 멍게에서 수압수용체세포 형성은 1차 신경유도기부터 후기 낭배기까지 FGF 신호전달 과정을 필요로 한다는 것이 밝혀졌다.

• The Korean Journal of Physiology and Pharmacology
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• 제17권2호
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• pp.133-137
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• 2013

Vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), P- and E-selectin play a pivotal role for initiation of atherosclerosis. Ginsenoside, a class of steroid glycosides, is abundant in Panax ginseng root, which has been used for prevention of illness in Korea. In this study, we investigated the mechanism(s) by which ginsenoside Rg2 may inhibit VCAM-1 and ICAM-1 expressions stimulated with lipopolysaccharide (LPS) in human umbilical vein endothelial cell (HUVEC). LPS increased VCAM-1 and ICAM-1 expression. Ginsenoside Rg2 prevented LPS-mediated increase of VCAM-1 and ICAM-1 expression. On the other hand, JSH, a nuclear factor kappa B (NF-${\kappa}B$) inhibitor, reduced both VCAM-1 and ICAM-1 expression stimulated with LPS. SB202190, inhibitor of p38 mitogen-activated protein kinase (p38 MAPK), and wortmannin, phosphatidylinositol 3-kinase (PI3-kinase) inhibitor, reduced LPS-mediated VCAM-1 but not ICAM-1 expression. PD98059, inhibitor of mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (MEK/ERK) did not affect VCAM-1 and ICAM-1 expression stimulated with LPS. SP600125, inhibitor of c-Jun N-terminal kinase (JNK), reduced LPS-mediated ICAM-1 but not VCAM-1 expression. LPS reduced IkappaB${\alpha}$ ($I{\kappa}B{\alpha}$) expression, in a time-dependent manner within 1 hr. Ginsenoside Rg2 prevented the decrease of $I{\kappa}B{\alpha}$ expression stimulated with LPS. Moreover, ginsenoside Rg2 reduced LPS-mediated THP-1 monocyte adhesion to HUVEC, in a concentration-dependent manner. These data provide a novel mechanism where the ginsenoside Rg2 may provide direct vascular benefits with inhibition of leukocyte adhesion into vascular wall thereby providing protection against vascular inflammatory disease.

• Asian Pacific Journal of Cancer Prevention
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• 제15권18호
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• pp.7617-7623
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• 2014

Objective: The mechanism of action of fatty acid synthase (FASN) in drug tolerance of breast cancer cells with epithelial-mesenchymal transition (EMT) features was investigated. Methods: The breast cancer cell line MCF-7-MEK5 with stably occurring EMT and tumour necrosis factor-${\alpha}$ (TNF-${\alpha}$) tolerance was used as the experimental model, whereas MCF-7 acted as the control. Tumour cells were implanted into nude mice for in vivo analysis, and cerulenin was used as a FASN inhibitor. RT-PCR, real-time quantitative PCR and Western blot were employed to detect the expression of FASN, TNFR-1, TNFR-2, Wnt-1, ${\beta}$-catenin and cytC at the RNA and protein levels. Results: Compared with MCF-7, TNFR-1 expression in MCF-7-MEK5 was slightly changed, TNFR-2 was decreased, and FASN, Wnt-1, ${\beta}$-catenin and cytC were increased. The expression of Wnt-1 and ${\beta}$-catenin in MCF-7-MEK5 decreased after cerulenin treatment, whereas cytC expression increased. Conclusions: The important function of FASN in the drug tolerance of breast cancer may be due to the following mechanisms: FASN downregulated TNFR-2 expression through lipid rafts to make the cells less sensitive to TNF-${\alpha}$, and simultaneously activated the Wnt-$1/{\beta}$-catenin signalling pathway. Thus, cytC expression increased, which provided cells with anti-apoptotic capacity and induced drug tolerance.