• BMB Reports
• /
• 제52권8호
• /
• pp.502-507
• /
• 2019

Translation is a costly, but inevitable, cell maintenance process. To reduce unnecessary ATP consumption in cells, a fine-tuning mechanism is needed for both ribosome biogenesis and translation. Previous studies have suggested that the ribosome functions as a hub for many cellular signals such as ribotoxic stress response, mammalian target of rapamycin (mTOR), and ribosomal S6 kinase (RSK) signaling. Therefore, we investigated the relationship between ribosomes and mitogen-activated protein kinase (MAPK) activation under ribotoxic stress conditions and found that the activation of c-Jun N-terminal kinases (JNKs) was suppressed by ribosomal protein knockdown but that of p38 was not. In addition, we found that JNK activation is driven by the association of inactive JNK in the 80S monosomes rather than the polysomes. Overall, these data suggest that the activation of JNKs by ribotoxic stress is attributable to 80S monosomes. These 80S monosomes are active ribosomes that are ready to initiate protein translation, rather than polysomes that are already acting ribosomes involved in translation elongation.

• 생약학회지
• /
• 제51권4호
• /
• pp.317-324
• /
• 2020

Mast cells play a key role in IgE-mediated allergic response. We investigated whether Swertia pseudochinensis Hara extract (SPE) inhibits IgE-mediated allergic response in mast cells and an allergic animal model. Additionally, we explored SPE's mechanism of action in mast cells. Our results showed that SPE inhibited both antigen-stimulated degranulation and the production of TNF-α and IL-4 in bone marrow-derived mast cells (BMMCs) and rat basophilic leukemia (RBL)-2H3 cells. SPE also suppressed allergic response in IgE-mediated passive cutaneous anaphylaxis (PCA) in mice. As for the mechanism of action of SPE in mast cells, it inhibited the activation of Syk kinase, a critical signaling protein in the FcεRI-mediated signaling pathway, and also the activation of LAT, a downstream adaptor protein of Syk. We further observed the reduced activation of mitogen-activated protein (MAP) kinases (P38, ERK1/2, and JNK) and Akt in mast cells. Our results described for the first time that SPE has an anti-allergic effect by suppressing mast cells through the inhibition of Syk kinase. Therefore, SPE may be useful for the treatment of type I allergic diseases.

• Toxicological Research
• /
• 제17권
• /
• pp.251-256
• /
• 2001

The expression of phase II detoxifying enzymes is affected by a variety of compounds and the induction of the enzymes plays an essential role in chemoprevention. A variety of phytochemicals such as sulfur-containing chemoprotective agents (SCC) may trigger cellular signals and activate phase II gene expression through ARE activation. see induces glutathione S-transferases. Studies were conducted to investigate the role of mitogen-activated protein (MAP) kinase and phosphatidylinositol 3-kinase (PI3-kinase) in the induction of GST (e.g. rGSTA2) by sec. We also studied the MAP kinase pathway responsible for the GST expression by see and compared that with the pathway activated by oxidative stress as a result of sulfur amino acids deprivation (SAAD). see inhibited phosphorylation of ERK1/2 although the effect of see on JNK and p38 MAP kinase was minimal. Wortmannin and LY294002. PI3-kinase inhibitors. abolished the increases in rGSTA2 mRNA and protein levels by SCC. Deprivation of cystine and methionine caused oxidative stress in H4IIE cells. as evidenced by a decrease in the reduced glutathione and an increase in prooxidant production. Electrophoretic mobility shift assay revealed that the ARE complex consisting of Nrf-1/2 and Maf proteins was activated 12~48 h. The rGSTA2 mRNA and protein levels were increased by SAAD. Activation of ARE and induction of rGSTA2 were both completely inhibited by PI3-kinase inhibitors. Inhibition of p38 MAP kinase by SB203580 prevented the ARE-mediated rGSTA2 induction. The results of this study showed that PI3-kinase might play an essential role in the ARE-mediated rGSTA2 induction by see or SAAD and that the dual MAP kinase pathways were responsible for the enzyme induction.

• Journal of Acupuncture Research
• /
• 제36권2호
• /
• pp.80-87
• /
• 2019

Background: This study investigated the anti-inflammatory effects of bee venom (BV) through the inhibition of nuclear factor kappa beta ($NF-{\kappa}B$) expression in macrophages and keratinocytes. Methods: Cell viability assays were performed to investigate the cytotoxicity of BV in activated macrophages [lipopolysaccharide (LPS)] and keratinocytes [interferon-gamma/tumor necrosis factor-alpha ($IFN-{\gamma}/TNF-{\alpha}$)]. A luciferase assay was performed to investigate the cellular expression of $NF-{\kappa}B$ in relation to BV dose. The expression of $NF-{\kappa}B$ inhibitors ($p-I{\kappa}B{\alpha}$, $I{\kappa}B{\alpha}$, and p50 and p65) were determined by Western Blot analysis, and the electromobility shift assay. A nitrite quantification assay was performed to investigate the effect of BV, and $NF-{\kappa}B$ inhibitor on nitric oxide (NO) production in macrophages. In addition, Western Blot analysis was performed to investigate the effect of BV on the expression of mitogen-activated protein kinases (MAPK) in activated macrophages and keratinocytes. Results: BV was not cytotoxic to activated macrophages and keratinocytes. Transcriptional activity of $NF-{\kappa}B$, and p50, p65, and $p-I{\kappa}B{\alpha}$ expression was reduced by treatment with BV in activated macrophages and keratinocytes. Treatment with BV and an $NF-{\kappa}B$ inhibitor, reduced the production of NO by activated macrophages, and also reduced $NF-{\kappa}B$ transcriptional activity in activated keratinocytes (compared with either BV, or $NF-{\kappa}B$ inhibitor treatment). Furthermore, BV decreased p38, p-p38, JNK, and p-JNK expression in LPS-activated macrophages and $IFN-{\gamma}/TNF-{\alpha}$-activated keratinocytes. Conclusion: BV blocked the signaling pathway of $NF-{\kappa}B$, which plays an important role in the inflammatory response in macrophages and keratinocytes. These findings provided the possibility of BV in the treatment of atopic dermatitis.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권15호
• /
• pp.6247-6251
• /
• 2014

Background: The aim of the present study was to investigate the involvement of emodin on the growth of human breast cancer MCF-7 and MDA-MB-231 cells and the estrogen (E2) signal pathway in vitro. Materials and Methods: MTT assays were used to detect the effects of emodin on E2 induced proliferation of MCF-7 and MDA-MB-231 cells. Flow cytometry (FCM) was applied to determine the effect of emodin on E2-induced apoptosis of MCF-7 cells. Western blotting allowed detection of the effects of emodin on the expression of estrogen receptor ${\alpha}$, cyclin D1 and B-cell lymphoma-2 (Bcl-2), mitogen-activated protein kinases (MAPK) and phosphatidylinostiol 3-kinases (PI3K). Luciferase assays were emplyed to assess transcriptional activity of $ER{\alpha}$. Results: Emodin could inhibit E2-induced MCF-7 cell proliferation and anti-apoptosis effects, and arrest the cell cycle in G0/G1 phase, further blocking the effect of E2 on expression and transcriptional activity of $ER{\alpha}$. Moreover, Emodin influenced the ER ${\alpha}$ genomic pathway via downregulation of cyclin D1 and Bcl-2 protein expression, and influenced the non-genomic pathway via decreased PI3K/Akt protein expression. Conclusions: These findings indicate that emodin exerts inhibitory effects on MCF-7 cell proliferation via inhibiting both non-genomic and genomic pathways.

• BMB Reports
• /
• 제42권6호
• /
• pp.380-386
• /
• 2009

In neurodegenerative diseases, such as Alzheimer' and Parkinson', microglial cell activation is thought to contribute to CNS injury by producing neurotoxic compounds. Prothrombin and kringle-2 increase levels of NO and the mRNA expression of iNOS, IL-1$\beta$, and TNF-$\alpha$ in microglial cells. In contrast, the human prothrombin kringle-2 derived peptide NSA9 inhibits NO release and the production of pro-inflammatory cytokines such as IL-1$\beta$, TNF-$\alpha$, and IL-6 in LPS-activated EOC2 microglia. In this study, we investigated the anti-inflammatory effects of NSA9 in human prothrombin- and kringle-2-stimulated EOC2 microglia. Treatment with 20-100 ${\mu}M$ of NSA9 attenuated both prothrombin- and kringle-2-induced microglial activation. NO production induced by MAPKs and NF-$\kappa$B was similarly reduced by inhibitors of ERK (PD98059), p38 (SB203580), NF-$\kappa$B (N-acetylcysteine), and NSA9. These results suggest that NSA9 acts independently as an inhibitor of microglial activation and that its effects in EOC2 microglia are not influenced by the presence of kringle-2.

• Journal of Microbiology and Biotechnology
• /
• 제27권2호
• /
• pp.242-250
• /
• 2017

Anti-photoaging effects of standardized Siegesbeckia glabrescens extract (SGE) and its major active compound kirenol were investigated using Hs68 human dermal fibroblasts and hairless mice, respectively. UVB-irradiated hairless mice that received oral SGE (600 mg/kg/day) showed reduced wrinkle formation and skinfold thickness compared with the UVB-irradiated control. Furthermore, SGE treatment increased the mRNA levels of collagen synthesis genes (COL1A1, COL3A1, COL4A1, and COL7A1) and activated antioxidant enzyme (catalase), while suppressing matrix metalloproteinase (MMP-2, -3, -9, and -13) expression. In Hs68 fibroblasts, kirenol also significantly suppressed MMP expression while increasing the expression of COL1A1, COL3A1, and COL7A1. Collectively, our data demonstrate that both SGE and kirenol attenuated UVB-induced photoaging in hairless mice and fibroblasts through inhibition of the mitogen-activated protein kinases and nuclear factor kappa B pathways, suggesting that SGE has potential to serve as a natural anti-photoaging nutraceutical.

• International Journal of Oral Biology
• /
• 제42권4호
• /
• pp.149-153
• /
• 2017

Cyclooxygenase-2 (COX-2)-mediated prostaglandin $E_2$ ($PGE_2$) plays a key role in development and progression of inflammatory responses and Porphyromonas gingivalis is a common endodontic pathogen. In this study, we investigated induction of COX-2 and $PGE_2$ by P. gingivalis in human dental pulp cells (HDPCs). P. gingivalis increased expression of COX-2, but not that of COX-1. Increased levels of $PGE_2$ were released from P. gingivalis-infected HDPCs and this $PGE_2$ increase was blocked by celecoxib, a selective COX-2 inhibitor. P. gingivalis activated all three types of mitogen-activated protein kinases (MAPKs). P. gingivalis-induced activation of nuclear $factor-{\kappa}B$ ($NF-{\kappa}B$) was demonstrated by the results of phosphorylation of $NF-{\kappa}B$ p65 and degradation of inhibitor of ${\kappa}B-{\alpha}$ ($I{\kappa}B-{\alpha}$). Pharmacological inhibition of each of the three types of MAPKs and $NF-{\kappa}B$ substantially attenuated P. gingivalis-induced $PGE_2$ production. These results suggest that P. gingivalis should promote endodontic inflammation by stimulating dental pulp cells to produce $PGE_2$.

• BMB Reports
• /
• 제41권7호
• /
• pp.523-528
• /
• 2008

BMI-1026 is a synthetic aminopyrimidine compound that targets cyclin dependent kinases (cdks) and was initially designed as a potential anticancer drug. Even though it has been well documented that BMI-1026 is a potent cdk inhibitor, little is known about the cellular effects of this compound. In this study, we examined the effects of BMI-1026 treatment on inducing premature senescence and then evaluated the biochemical features of BMI-1026-induced premature senescence. From these experiments we determined that BMI-1026 treatment produced several biochemical features of premature senescence and also stimulated expression of mitogen activated protein kinase (MAPK) family proteins. BMI-1026 treatment caused nuclear translocation of activated Erk1/2 and the formation of senescence associated heterochromatin foci in 5 days. The heterochromatin foci formation was perturbed by inhibition of Erk1/2 activation.

• Journal of Microbiology and Biotechnology
• /
• 제29권1호
• /
• pp.11-20
• /
• 2019

Ecklonia cava, an edible marine brown alga (Laminariaceae), is a rich source of bioactive compounds such as fucoidan and phlorotannins. Ecklonia cava extract (ECE) was prepared using 70% ethanol extraction and ECE contained 67% and 10.6% of total phlorotannins and dieckol, respectively. ECE treatment significantly inhibited receptor activator of nuclear $factor-{\kappa}B$ ligand (RANKL)-induced osteoclast differentiation of RAW 264.7 cells and pit formation in bone resorption assay (p <0.05). Moreover, it suppressed RANKL-induced $NF-{\kappa}B$ and mitogen-activated protein kinase signaling in a dose dependent manner. Downregulated osteoclast-specific gene (tartrate-resistant acid phosphatase, cathepsin K, and matrix metalloproteinase-9) expression and osteoclast proliferative transcriptional factors (nuclear factor of activated T cells-1 and c-fos) confirmed ECE-mediated suppression of osteoclastogenesis. ECE treatment ($100{\mu}g/ml$) increased heme oxygenase-1 expression by 2.5-fold and decreased intercellular reactive oxygen species production during osteoclastogenesis. The effective inhibition of RANKL-stimulated osteoclast differentiation and oxidative stress by ECE suggest that ECE has therapeutic potential in alleviating osteoclast-associated disorders.