• The Korean Journal of Physiology and Pharmacology
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• 제25권6호
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• pp.593-601
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• 2021

Primary cilia on kidney tubular cells play crucial roles in maintaining structure and physiological function. Emerging evidence indicates that the absence of primary cilia, and their length, are associated with kidney diseases. The length of primary cilia in kidney tubular epithelial cells depends, at least in part, on oxidative stress and extracellular signal-regulated kinase 1/2 (ERK) activation. Hydrogen sulfide (H₂S) is involved in antioxidant systems and the ERK signaling pathway. Therefore, in this study, we investigated the role of H₂S in primary cilia elongation and the downstream pathway. In cultured Madin-Darby Canine Kidney cells, the length of primary cilia gradually increased up to 4 days after the cells were grown to confluent monolayers. In addition, the expression of H₂S-producing enzyme increased concomitantly with primary cilia length. Treatment with NaHS, an exogenous H₂S donor, accelerated the elongation of primary cilia whereas DL-propargylglycine (a cystathionine γ-lyase inhibitor) and hydroxylamine (a cystathionine-β-synthase inhibitor) delayed their elongation. NaHS treatment increased ERK activation and Sec10 and Arl13b protein expression, both of which are involved in cilia formation and elongation. Treatment with U0126, an ERK inhibitor, delayed elongation of primary cilia and blocked the effect of NaHS-mediated primary cilia elongation and Sec10 and Arl13b upregulation. Finally, we also found that H₂S accelerated primary cilia elongation after ischemic kidney injury. These results indicate that H₂S lengthens primary cilia through ERK activation and a consequent increase in Sec10 and Arl13b expression, suggesting that H₂S and its downstream targets could be novel molecular targets for regulating primary cilia.

• 생명과학회지
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• 제26권10호
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• pp.1182-1188
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• 2016

Membrane associated guanylate kinase inverted-3 (MAGI-3)는 세포-세포 연접의 형성을 유도하는 막단백질인 membrane associated guanylate kinases (MAGUKs)의 한 종류 단백질로 140 kDa 크기를 가진다. MAGI-3는 PTEN/MMAC와 함께 협력하여 AKT/PKB의 kinase 활성을 조절하거나 MAPKs 신호전달경로로 ERK 활성을 조절로 한다. Coxsackievirus B3 (CVB3)는 가장 일반적으로 감염된 심근 세포 사멸으로 인한 바이러스성 심근염을 일으키는 enterovirus에 속하는 인간 병원체이다. 이전 연구에서 protein kinase B (PKB, 또는 AKT)와 extracellular signal-regulated kinases 1/2 (ERK1/2)의 활성은 HeLa 세포에서 CVB3 복제를 위해 필수적임이 밝혀졌다. 본 연구에서 enterovirus 복제와 AKT 신호 활성조절에서 MAGI-3의 역할을 검증하였다. MAGI-3-Flag의 발현은 CVB3 감염 후에 AKT 신호 활성과 viral capsid protein VP1의 발현을 유도하였으며 이는 MAGI-3에 의한 enterovirus 증식 조절을 보여주었다. AKT 신호는 MAGI-3 발현에 의해 enterovirus 감염과 함께 유의하게 증가하고 이것은 감염 바이러스의 증식을 활발하게 유도함을 확인하였다. 이 결과는 MAGI-3의 발현은 AKT와 ERK의 활성이 증가하고, 더 나아가 바이러스 증식과 연관이 있다는 것을 입증한다. MAGI-3는 아마도 AKT 신호 조절을 통해 enterovirus 증식 조절에 중요한 역할을 할 것으로 생각된다.

• 대한본초학회지
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• 제22권2호
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• pp.147-153
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• 2007

Objectives : Sophora flavescens (SF) is widely used in traditional herbal medicine in Korea and is well recognized for its anti-inflammatory effect. However, its effect on Tumornecrosis factor alpha (Tnf) production in BV2 microglial cell is not yet known. Methods : We investigated the effect of SF on the production and expression of Tnf, a well known inflammatory mediator, in lipopolysaccaride (LPS)-activated BV2 microglial cells. Results : The LPS-induced Tnf production was markedly reduced by treatment with SF (50 ${\mu}g/ml$). In reverse transcription polymerase chain reaction (RT-PCR) analysis, SF suppressed the LPS activated expression of Tnf mRNA. In addition, Western blot analysis confirmed that SF suppressed the expression of Tnf. Sophora flavescens also inhibited the LPS-induced phosphylation of extracellular signal-regulated kinases (ERK), which mediate the Tnfproduction signaling pathway whereas LPS-induced phosphylation of p38 mitogen activated protein kinase (p38 MAPK), and c-Jun NH2-terminal kinases (JNK) was not inhibited by SF, which implies that SF suppresses LPS-induced Tnf production via the ERK mediated pathway. Conclusion : Taken together, these findings indicated that SF inhibits LPS-induce Tnf production, and that this inhibitory effect is mediated via the ERK pathway.

• Natural Product Sciences
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• 제15권1호
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• pp.32-36
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• 2009

Glutamate causes neurotoxicity through formation of reactive oxygen species and activation of mitogen-activated protein kinase (MAPK) pathways. MAPK phosphatase-1 (MKP-1) is one of the phosphatases responsible for dephosphorylation/deactivation of three MAPK families: the extracellular signal-regulated kinase-1/2 (ERK-1/2), the c-Jun N-terminal kinase-1/2 (JNK-1/2), and the p38 MAPK. In this report, the potential involvement of MKP-1 in neuroprotective effects of curcumin, the active ingredient of turmeric (Curcuma longa), was examined using HT22 cells. Glutamate caused cell death and activation of ERK-1/2 but not p38 MAPK or JNK-1/2. Blockage of ERK-1/2 by its inhibitor protected HT22 cells against glutamate-induced toxicity. Curcumin attenuated glutamate-induced cell death and ERK-1/2 activation. Interestingly, curcumin induced MKP-1 activation. In HT22 cells transiently transfected with small interfering RNA against MKP-1, curcumin failed to inhibit glutamate-induced ERK-1/2 activation and to protect HT22 cells from glutamate-induced toxicity. These results suggest that curcumin can attenuate glutamate-induced neurotoxicity by activating MKP-1 which acts as the negative regulator of ERK-1/2. This novel pathway may contribute to and explain at least one of the neuroprotective actions of curcumin.

• Animal cells and systems
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• 제16권3호
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• pp.190-197
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• 2012

Depression is one of the most prevalent diseases of alcohol abuse. Brain-derived neurotrophic factor (BDNF) plays a critical role in cell survival in the hippocampus. Phosphorylation of extracellular signal-regulated kinase 1/2 (p-ERK1/2) is induced by BDNF, and it regulates cell proliferation and differentiation in the brain. We investigated the effects of alcohol intake on depression-like behavior, cell proliferation, expressions of BDNF and its downstream molecules in the hippocampus using Mongolian gerbils. The gerbils were divided into four groups: control group, 0.5 g/kg alcohol-treated group, 1 g/kg alcohol-treated group, 2 g/kg alcohol-treated group. Each dose of alcohol was orally administered for 3 weeks. The present results demonstrated that alcohol intake induced depression-like behavior. Both 5-hydroxytryptamine synthesis and its synthesizing enzyme tryptophan hydroxylase expression in the dorsal raphe and cell proliferation in the hippocampal dentate gyrus were decreased by alcohol intake. Alcohol intake suppressed BDNF expression, and resulted in the decrease of its downstream molecules, pERK1/2 and Bcl-2, in the hippocampus. We showed that alcohol intake may lead to a depressed-like state with reduced hippocampal cell proliferation through inhibition of the BDNF-ERK signaling pathway.

• Tuberculosis and Respiratory Diseases
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• 제72권3호
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• pp.275-283
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• 2012

Background: Healthy individuals who develop nontuberculous mycobacteria (NTM) lung disease are likely to have specific susceptibility factors which can lead to a NTM infection. The aim of the present study was to investigate the mechanism underlying innate immune responses, including the role of mitogen-activated protein kinase (MAPK), in Mycobacterium abscessus lung disease. Methods: Extracellular signal-regulated kinase (ERK1/2) and p38 MAPK expression in monocytes from peripheral blood mononuclear cells were measured by Western blot analysis after stimulation by Mycobacterium avium in five patients with M. abscessus lung disease and seven healthy controls. A M. avium-induced cytokine assay was performed after inhibition of ERK1/2 and p38 MAPK pathways. Results: Mycobacterium avium induced p38 and ERK1/2 expression in monocytes from healthy controls and subsequently upregulated tumor necrosis factor (TNF)-${\alpha}$, interleukin (IL)-6, and IL-10 production. In monocytes from patients with M. abscessus lung disease, however, induction of p38 and ERK1/2 expression, and the production of TNF-${\alpha}$, IL-6, and IL-10 were significantly lower. Conclusion: Decreased activity of MAPK and cytokine secretion in monocytes from patients with M. abscessus lung disease may provide an explanation regarding host susceptibility to these uncommon infections.

• Journal of Ginseng Research
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• 제42권2호
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• pp.233-237
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• 2018

• The Korean Journal of Physiology and Pharmacology
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• 제17권4호
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• pp.307-314
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• 2013

Connective tissue growth factor (CTGF) is a potent pro-fibrotic factor, which is implicated in fibrosis through extracellular matrix (ECM) induction in diabetic cardiovascular complications. It is an important downstream mediator in the fibrotic action of transforming growth factor ${\beta}$ ($TGF{\beta}$) and is potentially induced by hyperglycemia in human vascular smooth muscle cells (VSMCs). Therefore, the goal of this study is to identify the signaling pathways of CTGF effects on ECM accumulation and cell proliferation in VSMCs under hyperglycemia. We found that high glucose stimulated the levels of CTGF mRNA and protein and followed by VSMC proliferation and ECM components accumulation such as collagen type 1, collagen type 3 and fibronectin. By depleting endogenous CTGF we showed that CTGF is indispensable for the cell proliferation and ECM components accumulation in high glucose-stimulated VSMCs. In addition, pretreatment with the MEK1/2 specific inhibitors, PD98059 or U0126 potently inhibited the CTGF production and ECM components accumulation in high glucose-stimulated VSMCs. Furthermore, knockdown with ERK1/2 MAPK siRNA resulted in significantly down regulated of CTGF production, ECM components accumulation and cell proliferation in high glucose-stimulated VSMCs. Finally, ERK1/2 signaling regulated Egr-1 protein expression and treatment with recombinant CTGF reversed the Egr-1 expression in high glucose-induced VSMCs. It is conceivable that ERK1/2 MAPK signaling pathway plays an important role in regulating CTGF expression and suggests that blockade of CTGF through ERK1/2 MAPK signaling may be beneficial for therapeutic target of diabetic cardiovascular complication such as atherosclerosis.

• The Korean Journal of Physiology and Pharmacology
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• 제8권4호
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• pp.187-194
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• 2004

Middle cerebral artery occlusion (MCAO) results in cell death by activation of complex signal pathways for cell death and survival. Hypothermia is a robust neuroprotectant, and its effect has often been attributed to various mechanisms, but it is not yet clear. Upstream from the cell death promoters and executioners are several enzymes that may activate several transcription factors involved in cell death and survival. In this study, we immunohistochemically examined the phosphorylation of mitogen-activated protein kinase, extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 kinase during early period of the ischemic injury, following 2 hours (h) of transient MCAO. Increased phosphorylation of ERK and p38 was observed in the vessels at 3 h, neuron-like cells at 6 and 12 h and glia-like cells at 12 h. Activation of JNK was not remarkable, and a few cells showed active JNK following ischemia. Phosphorylation of Elk-1, a transcription factor, was reduced by ischemic insult. Hypothermia attenuated the activation of ERK, p38 and JNK, and inhibited reduction of Elk-1. These data suggest that signals via different MAPK family members converge on the cell damage process and hypothermia protects the brain by interfering with these pathways.

• 한국해양생명과학회지
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• 제6권2호
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• pp.58-65
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• 2021

노화가 진행될수록 활성산소종으로 인하여 피부 보습은 떨어지고 피부 장벽은 붕괴되어 피부가 손상된다. 본 연구에서는 인천 동막 해변에 서식하는 염생식물인 갯끈풀(Spartina anglica; SAE)과 갯메꽃(Calystegia soldanella; CSE)을 70% 에탄올(EtOH)로 추출하여 피부 보습 및 피부 장벽 기능 강화에 대한 효능을 평가하였다. 이 추출물들에 대한 피부 각질형성세포(HaCaT cell)에서 세포독성을 WST-8 assay를 이용하여, 세포 생존율이 90% 이상을 보이는 농도를 선별하여 추가 실험을 진행하였다. ABTS 라디칼 소거능을 통해 항산화 효과를 확인한 결과, SAE와 CSE는 높은 라디칼 소거능을 보였다. 피부 보습과 관련된 인자들인 filaggrin (FGL), aquaporin 3(AQP3), hyaluronan synthase 2 (HAS2)과 피부 장벽 기능과 연관 있는 transglutaminase 1 (TGM1)과 involucrin (INV)의 유전자 수준에서의 발현 변화를 측정한 결과, SAE에 의해 AQP3, HAS2, TGM1의 발현이 증가하였으나, CSE는 변화가 없는 것을 확인할 수 있었다. SAE에 의한 세포 내 신호전달 경로를 확인하기 위해 western blot 분석을 수행하였다. Extracellular signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 mitogen activated protein kinase의 활성이 SAE에 의하여 상향 조절되었음을 확인하였다. 이러한 결과는 갯끈풀 추출물이 피부 보습 및 피부 장벽 기능 강화를 위한 화장품의 기능성 소재로 사용될 수 있음을 시사한다.