• Journal of Applied Biological Chemistry
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• 제66권
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• pp.447-454
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• 2023

인간이 살아가는 환경에는 인체에 침입하여 건강한 삶을 영위하는 것을 방해하는 다양한 항원들이 존재하며, 면역 체계는 복잡한 기전을 통하여 이를 인식하고 제거한다. 대식세포는 선천 면역체계에 관연하는 면역세포로 체내 널리 분포하고 있으며, inducible nitric oxide synthase로 유도된 산화질소, cyclooxygenase-2로 유도된 prostaglandin E2 그리고 tumor necrosis factor-alpha 등의 전염증성 사이토카인 같은 다양한 면역 조절 물질을 생산한다. 흰점박이꽃무지유충은 미래 식량 수급 문제에 대한 대안으로 등장한 식용 곤충의 일종으로, 기존 mitogen activated protein kinases 및 nuclear factor-kappa B (NF-κB) 신호전달 경로를 경유하는 RAW264.7 대식세포의 활성화를 통한 면역 조절 효과가 보고되었다. 본 연구에서는 RAW264.7 세포에서 흰점박이꽃무지유충 추출물에 의해 유도된 면역 조절 물질의 발현이 toll-like receptor 4, mitogen activated protein kinases 및 nuclear factor-kappa B 신호전달 경로의 약리학적 억제제에 의해 어떻게 변화되었는지 확인하였다. 그 결과, 흰점박이꽃무지유충 처리에 의해 증가된 면역 조절 물질의 발현이 c-Jun N-terminal kinase (JNK) 억제제 및 NF-κB 억제제 처리에 의해 감소하는 것을 확인하였다. 또한, toll-like receptor 4(TLR4) 억제제 처리에 의해서는 흰점박이꽃무지유충 추출물 처리에 의해 증가된 면역 조절 물질의 발현과 JNK 및 NF-κB의 인산화 감소를 확인하였다. 우리의 이러한 연구는 흰점박이꽃무지유충이 TLR4-JNK/NF-κB 신호전달의 관여에 의해 RAW264.7 세포를 활성화하는 것을 시사한다.

• Annals of dermatology
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• 제30권6호
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• pp.645-652
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• 2018

Background: Adiponectin, an adipokine secreted from adipocytes, affects energy metabolism and also shows anti-diabetic and anti-inflammatory properties. Recent studies have reported that adiponectin plays a role in regulating skin inflammation. Objective: This study aimed to investigate the effect of adiponectin on the expression of filaggrin (FLG) in normal human epidermal keratinocytes (NHEKs). Methods: NHEKs were serum-starved for 6h before being treated with adiponectin. Afterward, cell viability was assessed by MTT assay. We also treated with calcium, interleukin (IL)-4, and IL-13 to provide positive and negative comparative controls, respectively. Gene mRNA expression was quantified using real time reverse transcription polymerase chain reaction, and protein expression was evaluated using Western blot. To evaluate the relationship among mitogen-activated protein kinases (MAPKs), activator protein 1 (AP-1), and FLG, we also treated cells with inhibitors for MAPKs JNK, p38, and ERK1/2. Results: FLG and FLG-2 mRNA expression in NHEKs significantly increased after treatment with $10{\mu}g/ml$ adiponectin. Adiponectin also restored FLG and FLG-2 mRNA expression that was otherwise inhibited by treatment with IL-4 and IL-13. Adiponectin induced FLG expression via AP-1 and MAPK signaling. Conclusion: Adiponectin positively regulated the expression of FLG and could be useful as a therapeutic agent to control diseases related to disrupted skin barrier function.

• 대한통합의학회지
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• 제11권3호
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• pp.159-169
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• 2023

Purpose : Though other Citrus spp. have reported their anti-inflammatory and antioxidative activities in previous studies, the biological activity of Kiyomi (Citrus unshiu × C. sinensis) has not been reported yet. Therefore, this study attempted to analyze the anti-inflammatory mechanisms of Kiyomi leaf ethanol extract (KLEE) in lipopolysaccharide (LPS) stimulated RAW 264.7 cells. Methods : The cytotoxic effect of KLEE in RAW 264.7 cells was determined by WST-1 assay. Bacterial endotoxin, the concentration of nitric oxide (NO) was analyzed by the Griess reaction. In addition, Western blot analysis was applied to measure the protein expression level of inducible NO synthase (iNOS). The phosphorylated status of the critical inflammatory transcription factor, nuclear factor (NF)-𝜅B, and its upstream signaling molecules, phosphoinositide 3-kinase (PI3K)/Akt as well as mitogen-activated protein kinases (MAPKs), were also measured by Western blot analysis. Results : KLEE was not cytotoxic up to a concentration of 200 ㎍/㎖, and protein expression levels of iNOS and cyclooxygenase (COX)-2, enzymes that counteract NO and prostaglandin (PG) E2 production, were inhibited by KLEE treatment. The phosphorylated status of PI3K/Akt as well as MAPKs including extracellular regulated kinase (ERK), c-jun NH2kinase (JNK), and p38, were significantly attenuated by KLEE treatment in LPS stimulated RAW 264.7 cells. Moreover, one of phase II enzymes, heme oxygenase (HO)-1 which has known for its anti-inflammatory capacity, was strongly induced by KLEE treatment. Conclusion : Consequently, KLEE treatment significantly attenuated the production of NO as well as the expression levels of iNOS and COX-2 in LPS-stimulated RAW 264.7 cells. The inflammatory transcription factor, NF-𝜅B, as well as its upstream signaling molecules, PI3K/Akt and MAPKs, were also diminished by KLEE treatment with statistical significance in LPS-stimulated RAW 264.7 cells. These results suggest that KLEE might be a promising candidate for the attenuation of inflammatory disorders.

• 대한의생명과학회지
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• 제29권4호
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• pp.211-219
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• 2023

Caffeic acid phenethyl ester (CAPE) is an active component of propolis obtained from honeybee hives. CAPE possesses anti-mitogenic, anti-carcinogenic, anti-inflammatory, and immunomodulatory activities in diverse systems, which know as displays antioxidant activity and inhibits lipoxygenase activities, protein tyrosine kinase, and nuclear factor kappa B (NF-κB) activation. This study aimed to investigate the effect of CAPE on lipopolysaccharide (LPS)-induced human neutrophil phagocytosis. Human neutrophils were cultured with various concentrations of CAPE (1, 10, and 100 µM) with or without LPS. The pro-inflammatory proteins (tumor necrosis factor-alpha [TNF-α], interleukin [IL]-6 and IL-8) levels were measured after 4 h incubation. To investigate the intracellular signaling pathway, we measured the levels of mitogen-activated protein kinases (MAPK), including phosphorylation of p38, extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) and c-Jun N-terminal kinase (JNK). Next, to evaluate the potential phagocytosis, neutrophils were labeled with iron particles of superparamagnetic iron oxide nanoparticles (SPIONs, 40 nm) for 1 h in culture medium containing 5 mg/mL of iron. The labeling efficiency was determined by Prussian blue staining for intracellular iron and 3T-wighted magnetic resonance imaging. CAPE decreased the activation of intracellular signaling pathways, including ERK1/2 and c-Jun, and expression of pro-inflammatory cytokines, including TNF-α and IL-6, but had no effect on the signaling pathways of p38 and cytokine IL-8. Furthermore, images obtained after mannan-coated SPION treatment suggested that CAPE induced significantly higher signal intensities than the control or LPS group. Together, these results suggest that CAPE regulates LPS-mediated activation of human neutrophils to reduce phagocytosis.

• Clinical and Experimental Pediatrics
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• 제60권6호
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• pp.181-188
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• 2017

Purpose: Hypoxic-ischemic encephalopathy is a significant cause of neonatal morbidity and mortality. Erythropoietin (EPO) is emerging as a therapeutic candidate for neuroprotection. Therefore, this study was designed to determine the neuroprotective role of recombinant human EPO (rHuEPO) and the possible mechanisms by which mitogen-activated protein kinase (MAPK) signaling pathway including extracellular signal-regulated kinase (ERK1/2), JNK, and p38 MAPK is modulated in cultured cortical neuronal cells and astrocytes. Methods: Primary neuronal cells and astrocytes were prepared from cortices of ICR mouse embryos and divided into the normoxic, hypoxia (H), and hypoxia-pretreated with EPO (H+EPO) groups. The phosphorylation of MAPK pathway was quantified using western blot, and the apoptosis was assessed by caspase-3 measurement and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Results: All MAPK pathway signals were activated by hypoxia in the neuronal cells and astrocytes (P<0.05). In the neuronal cells, phosphorylation of ERK-1/-2 and apoptosis were significantly decreased in the H+EPO group at 15 hours after hypoxia (P<0.05). In the astrocytes, phosphorylation of ERK-1/-2, p38 MAPK, and apoptosis was reduced in the H+EPO group at 15 hours after hypoxia (P<0.05). Conclusion: Pretreatment with rHuEPO exerts neuroprotective effects against hypoxic injury reducing apoptosis by caspase-dependent mechanisms. Pathologic, persistent ERK activation after hypoxic injury may be attenuateed by pretreatment with EPO supporting that EPO may regulate apoptosis by affecting ERK pathways.

• Journal of Photoscience
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• 제9권2호
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• pp.229-232
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• 2002

There are two distinct UV-responsive signaling pathways in UV-irradiated mammalian cells, i.e., the DNA damage-dependent and -independent pathways. The former occurs in nucleus and results in growth arrest and apoptosis via post-translational modification of p53. The latter is initiated by oxidative stress and/or by damages in cell membrane or cytoplasm, which activate signaling cascade through intracellular molecules including mitogen activated protein kinases (MAPK). In normal human fibroblastic cells, all of MAPK family members, extracellular signal-related kinases (ERK), c-Jun N-terminal kinases (JNK) and p38, were rapidly phosphorylated following UV-irradiation. ERK phosphorylation was suppressed by an inhibitor of receptor tyrosine kinases (RTK). As ERK usually responds to mitogenic stimuli from RTK ligands, UV-induced ERK phosphorylation may be linked to the proliferation of survived cells. In contrast, phosphorylation of JNK and p38, as well as apoptosis, were modulated by the level of UV-generated oxidative stress Therefore, JNK and p38 may take part in oxidative stress-mediated apoptosis. Phosphorylation of p53 at Ser and Thr residues are essential for stabilization and activation of p53. Among several sites reported, we confirmed phosphorylation at Ser-15 and Ser-392 after UV-irradiation. Both of these were inhibited by a phosphoinositide 3-kinase inhibitor, presumably due to the shutdown of signals from DNA damage to p53. Phosphorylation at Ser-392 was also sensitive to an antioxidant and a p38 inhibitor, suggesting that Ser-392 of p53 is one of the possible points where DNA damage-dependent and -independent apoptic signals merge. Thus, MAPK pathway links UV-induced intracellular signals to the nuclear responses and modifies DNA damage-dependent cellular outcome, resulting in the determination of cell death.

• International Journal of Oral Biology
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• 제30권3호
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• pp.85-90
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• 2005

Homeostatic pH is very important for various cellular processes, including metabolism, survival, and death. An imbalanced-pH might induce cellular acidosis, which is involved in many abnormal events such as apoptosis and malignancy. One of several factors contributing to the onset of metabolic acidosis is the production of lactate and protons by lactate dehydrogenase (LDH) in anaerobic glycolysis. LDH is an important enzyme that catalyzes the reversible conversion of pyruvate to lactate. This study sought to examine whether decreases in extracellular pH induce apoptosis of CHO cells, and to elucidate the role of mitogen-activated protein kinases (MAPKs) in acidification-induced apoptosis. To test apoptotic signaling by acidification we used CHO dhfr cells that were sensitive to acidification, and CHO/anti-LDH cells that are resistant to acidification-induced apoptosis and have reduced LDH activity by stable LDH antisense mRNA expression. In the present study, cellular lactic acid-induced acidification and the role of MAPKs signaling in acidification-induced apoptosis were investigated. Acidification, which is caused by $HCO{_3}^-$-free conditions, induced apoptosis and MAPKs (ERK, JNK, and p38) activation. However, MAPKs were slightly activated in acidic conditions in the CHO/anti-LDH cells, indicating that lactic acid-induced acidification induces activation of MAPKs. Treatment with a p38 inhibitor, PD169316, increased acidification-induced apoptosis but apoptosis was not affected by inhibitors for ERK (U0126) or JNK (SP600125). Thus, these data support the hypothesis that activation of the p38 MAPK during acidification-induced apoptosis contributes to cell survival.

• The Korean Journal of Physiology and Pharmacology
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• 제10권4호
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• pp.199-205
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• 2006

The functional expression of potassium $(K^+)$ channels has electrophysiologically been studied in bone cells from several species, however, their identity and regulation of gene expressions in bone cells are not well known. In the present study, to investigate how $K^+$ channel expressions are regulated by estrogen, we measured changes of transcript levels of various $Ca^{2+}$-activated ($K_{Ca}$) and ATP-sensitive $K^+$ channels in rat osteoblastic ROS 17/2.8 cells after treatment with estrogen. Application of 17${\beta}$-estradiol $(E_2)$ for 24 h and 48 h increased mRNA and protein expressions of inwardly rectifying $K^+$ channel (Kir) 6.2 and type 2 small conductance $K_{Ca}$ channel (SK2), respectively. Combined treatment of cells with 17${\beta}-E_2$ and ICI 182,780, a pure antiestrogen, suppressed 17${\beta}-E_2$-induced alterations of SK2 and Kir6.2 mRNA levels. In addition, treatment of cells with U0126, a specific inhibitor of extracellular receptor kinases (ERK)1/2, and SP600125, a specific inhibitor of c-jun N-terminal kinase (JNK) blocked the enhancing effects of 17${\beta}-E_2$ on SK2 and Kir6.2 protein expressions. On the other hand, blocking of p38 mitogen-activated protein kinase had no effect. Taken together, these results indicate that 17${\beta}-E_2$ modulates SK2 and Kir6.2 expressions through the estrogen receptor, involving ERK1/2 and JNK activations.

• Food Science and Biotechnology
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• 제18권5호
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• pp.1063-1070
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• 2009

Dangyuja (Citrus grandis Osbeck) is a native plant growing only on Jeju Island in Korea. In this study, antiinflammatory effect of dangyuja leaves on a murine macrophage cell line was investigated. RAW 264.7 murine macrophage cells were stimulated with lipopolysaccharide (LPS, $1{\mu}g/mL$) to induce expression of pro-inflammatory markers [interleukin (IL)-6 and inducible nitric oxide synthase (iNOS)]. The crude extract (80% MeOH Ex.) and solvent fractions (hexane, $CHCl_3$, EtOAc, BuOH, and $H_2O$ Ex.) were obtained from dangyuja leaves. The $CHCl_3$ fraction inhibited the nitric oxide (NO) and IL-6 production in a dose-dependent manner. Also, the $CHCl_3$ fraction inhibited mRNA expression and protein levels of iNOS in a dose-dependent manner. Furthermore, the $CHCl_3$ fraction inhibited LPS-induced nuclear factor (NF)-${\kappa}B$ activation and phosphorylation of mitogen-activated protein kinases (MAPKs: ERK, JNK, and p38). These results suggest that dangyuja leaves may inhibit LPS-induced production of inflammatory markers by blocking NF-${\kappa}B$ and MAPKs signaling in RAW 264.7 cells.

• Journal of Microbiology and Biotechnology
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• 제18권6호
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• pp.1170-1178
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• 2008

The cyclopentenone prostaglandins (cyPGs) prostaglandin $A_1$ ($PGA_1$) and 15-deoxy-${\Delta}^{12,14}$-prostaglandin $J_2$ (15d-$PGJ_2$) have been reported to exhibit antiinflammatory activity in activated monocytes/macrophages. However, the effects of these two cyPGs on the expression of cytokine genes may differ. In this study, we investigated the mechanism of action of $PGA_1$ in lipopolysaccharide (LPS)-induced expression of inter leu kin (IL)-10 mRNA in mouse peritoneal macrophages. 15d-$PGJ_2$ inhibited expression of LPS-induced IL-10, whereas $PGA_1$ increased LPS-induced IL-10 expression. This synergistic effect of $PGA_1$ on LPS-induced IL-10 expression reached a maximum as early as 2 h after simultaneous $PGA_1$ and LPS treatment ($PGA_1$/LPS), and did not require new protein synthesis. The synergistic effect of $PGA_1$ was inhibited by GW9662, a specific peroxisome proliferator-activated receptor ${\gamma}(PPAR{\gamma})$ antagonist, and Bay-11-7082, a NF-${\kappa}B$ inhibitor. The extracellular signal-regulated kinases (ERK) inhibitor PD98059 increased the expression of $PGA_1$/LPS-induced IL-10 mRNA, rather than inhibiting the IL-10 expression. Moreover, $PGA_1$ inhibited LPS-induced ERK phosphorylation. The synergistic effect of $PGA_1$ on LPS-induced IL-10 mRNA and protein production was inhibited by p38 inhibitor PD169316, and $PGA_1$ increased LPS-induced p38 phosphorylation. In the case of stress-activated protein kinase/c-Jun $NH_2$-terminal kinase (SAPK/JNK), the SAPK/JNK inhibitor SP600125 did not inhibit IL-10 mRNA synthesis but inhibited the production of IL-10 protein remarkably. These results suggest that the synergistic effect of $PGA_1$ on LPS-induced IL-10 expression is NF-${\kappa}B$-dependent and mediated by mitogen-activated protein (MAP) kinases, p38, and SAPK/JNK signaling pathways, and also associated with the $PPAR{\gamma}$ pathway. Our data may provide more insight into the diverse mechanisms of $PGA_1$ effects on the expression of cytokine genes.