scholarly journals Puerarin Suppress Apoptosis of Human Osteoblasts via ERK Signaling Pathway

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Ling-juan Liu ◽  
Li-qun Liu ◽  
Tao Bo ◽  
Shi-jun Li ◽  
Zhen Zhu ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Chinese Herb ◽  
Inhibitory Effect ◽  
Erk Signaling ◽  
Control Group ◽  
Human Osteoblasts ◽  
Antiapoptotic Effect ◽  
Protein Levels ◽  
Bax Protein ◽  
Radix Puerariae

Puerarin, the main isoflavone glycoside extracted from Radix Puerariae, is an isoflavone traditional Chinese herb. Previous studies have demonstrated that puerarin could regulate osteoblast proliferation and differentiation to promote bone formation. However, the effect of puerarin on the process of human osteoblasts (hOBs) apoptosis is still unclear. In this study, we detected the function of puerarin on serum-free-induced cell apoptosis using ELISA and TUNEL arrays and then found that the mortality of hOBs was significantly decreased after exposure to 10−10–10−6 M puerarin and reached the maximal antiapoptotic effect at the concentration of 10−8 M. In addition, compared with the control group, puerarin notably increased the Bcl-2 protein levels while it decreased the Bax protein levels in the hOBs in a dose-dependent way. 10−7 M puerarin decreased the Bax/Bcl-2 ratio with a maximal decrease to 0.08. Moreover, puerarin activated ERK signaling pathways in hOBs, and the antiapoptotic effect induced by puerarin was abolished by incubation of ERK inhibitor PD98059. Similarly, the estrogen receptor antagonist ICI182780 also suppressed the inhibitory effect of puerarin on hOBs apoptosis. In conclusion, puerarin could prevent hOBs apoptosis via ERK signaling pathway, which might be effective in providing protection against bone loss and bone remolding associated with osteoporosis.

scholarly journals Extracellular signal-regulated kinases (ERK1/2) signaling pathway plays a role in cortisol secretion in the long-term hypoxic ovine fetal adrenal near term

2013 ◽  
Vol 304 (8) ◽  
pp. R636-R643 ◽  
Author(s):  
Vladimir E. Vargas ◽  
Kanchan M. Kaushal ◽  
Tshepo R. Monau ◽  
Dean A. Myers ◽  
Charles A. Ducsay
Keyword(s):  
Protein Kinase ◽  
Signaling Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Erk Signaling ◽  
Control Group ◽  
Cortisol Secretion ◽  
Protein Levels ◽  
Extracellular Signal ◽  
Acth Treatment

This study assessed the role of the extracellular signal-regulated kinase (ERK) signaling pathway on the previously observed enhanced cortisol secretion in response to adrenocorticotropic hormone (ACTH) treatment in fetal adrenocortical cells (FACs) from long-term hypoxic (LTH) ovine fetuses. Ewes were maintained at high altitude (3,820 m) from ∼40 to 138–141 days gestation when FACs were collected and challenged with either ACTH (10 nM) or 8-bromoadenosine 3′,5′-cyclic monophosphate (8-bromo-cAMP, 10 mM) in the presence or absence of the mitogen-activated protein kinase/extracellular signal-regulated protein kinase (MEK)/ERK inhibitor UO126 (10 μM). FACs from age-matched normoxic fetuses served as controls. Media and FACs were collected at selected time intervals after ACTH or 8-bromo-cAMP stimulation for cortisol measurement and Western analysis of ERK1/2 and phospho-ERK1 and -2 (pERK1/2). After ACTH or 8-bromo-cAMP treatment, cortisol production was greater in the LTH group compared with control ( P < 0.05). UO126 reduced ACTH and 8-bromo-cAMP-mediated cortisol output in both groups ( P < 0.01 vs. ACTH or 8-bromo-cAMP alone). Under basal conditions, ERK1/2 and pERK1/2 were not different between LTH and normoxic fetuses. In response to ACTH or 8-bromo-cAMP treatment, ERK1/2 were not different between groups; however, pERK1/2 were elevated in the LTH FACs compared with normoxic control FACs. ERK1/2 phosphorylation declined following ACTH treatment in the control group, but UO126 had no effect on ERK1/2 compared with untreated levels. Both ACTH and 8-bromo-cAMP treatment resulted in a decline of protein levels. UO126 pretreatment virtually eliminated pERK1/2 expression. We conclude that basal ERK signaling in FACs is necessary for normal cortisol production and sustained pERK in LTH adrenals enhances cortisol production.

scholarly journals Anti-Inflammatory Effect of Auranofin on Palmitic Acid and LPS-Induced Inflammatory Response by Modulating TLR4 and NOX4-Mediated NF-κB Signaling Pathway in RAW264.7 Macrophages

2021 ◽  
Vol 22 (11) ◽  
pp. 5920
Author(s):  
Hyun Hwangbo ◽  
Seon Yeong Ji ◽  
Min Yeong Kim ◽  
So Young Kim ◽  
Hyesook Lee ◽  
...  
Keyword(s):  
Palmitic Acid ◽  
Signaling Pathway ◽  
Chronic Inflammation ◽  
Inhibitory Effect ◽  
Simultaneous Treatment ◽  
Monocyte Chemoattractant Protein 1 ◽  
Protein Levels ◽  
Raw264.7 Macrophages ◽  
Anti Inflammatory ◽  
Factor Α

Chronic inflammation, which is promoted by the production and secretion of inflammatory mediators and cytokines in activated macrophages, is responsible for the development of many diseases. Auranofin is a Food and Drug Administration-approved gold-based compound for the treatment of rheumatoid arthritis, and evidence suggests that auranofin could be a potential therapeutic agent for inflammation. In this study, to demonstrate the inhibitory effect of auranofin on chronic inflammation, a saturated fatty acid, palmitic acid (PA), and a low concentration of lipopolysaccharide (LPS) were used to activate RAW264.7 macrophages. The results show that PA amplified LPS signals to produce nitric oxide (NO) and various cytokines. However, auranofin significantly inhibited the levels of NO, monocyte chemoattractant protein-1, and pro-inflammatory cytokines, such as interleukin (IL)-1β, tumor necrosis factor-α, and IL-6, which had been increased by co-treatment with PA and LPS. Moreover, the expression of inducible NO synthase, IL-1β, and IL-6 mRNA and protein levels increased by PA and LPS were reduced by auranofin. In particular, the upregulation of NADPH oxidase (NOX) 4 and the translocation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) induced by PA and LPS were suppressed by auranofin. The binding between the toll-like receptor (TLR) 4 and auranofin was also predicted, and the release of NO and cytokines was reduced more by simultaneous treatment with auranofin and TLR4 inhibitor than by auranofin alone. In conclusion, all these findings suggested that auranofin had anti-inflammatory effects in PA and LPS-induced macrophages by interacting with TLR4 and downregulating the NOX4-mediated NF-κB signaling pathway.

scholarly journals Mechanism of KLF4 Protection against Acute Liver Injury via Inhibition of Apelin Signaling

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Weitao Ji ◽  
Hongyun Shi ◽  
Hailin Shen ◽  
Jing Kong ◽  
Jiayi Song ◽  
...  
Keyword(s):  
Liver Injury ◽  
Signaling Pathway ◽  
Acute Liver Injury ◽  
Control Group ◽  
Necrosis Factor Alpha ◽  
Protein Levels ◽  
Klf4 Expression ◽  
Mrna And Protein Expression

Krüppel-like factor 4 (KLF4) is a key transcription factor that regulates genes involved in the proliferation or differentiation in different tissues. Apelin plays roles in cardiovascular functions, metabolic disease, and homeostatic disorder. However, the biological function of apelin in liver disease is still ongoing. In this study, we investigated the mechanism of KLF4-mediated protection against acute liver injury via the inhibition of the apelin signaling pathway. Mice were intraperitoneally injected with carbon tetrachloride (CCl4; 0.2 mL dissolved in 100 mL olive oil, 10 mL/kg) to establish an acute liver injury model. A KLF4 expression plasmid was injected through the tail vein 48 h before CCl4 treatment. In cultured LX-2 cells, pAd-KLF4 or siRNA KLF4 was overexpressed or knockdown, and the mRNA and protein levels of apelin were determined. The results showed that the apelin serum level in the CCl4-injected group was higher than that of control group, and the expression of apelin in the liver tissues was elevated while KLF4 expression was decreased in the CCl4-injected group compared to the KLF4-plasmid-injected group. HE staining revealed serious hepatocellular steatosis in the CCl4-injected mice, and KLF4 alleviated this steatosis in the mice injected with KLF4 plasmid. In vitro experiments showed that tumor necrosis factor-alpha (TNF-α) could downregulate the transcription and translation levels of apelin in LX-2 cells and also upregulate KLF4 mRNA and protein expression. RT-PCR and Western blotting showed that the overexpression of KLF4 markedly decreased basal apelin expression, but knockdown of KLF4 restored apelin expression in TNF-α-treated LX-2 cells. These in vivo and in vitro experiments suggest that KLF4 plays a key role in inhibiting hepatocellular steatosis in acute liver injury, and that its mechanism might be the inhibition of the apelin signaling pathway.

scholarly journals Liraglutide Promotes Osteoblastic Differentiation in MC3T3-E1 Cells by ERK5 Pathway

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yue Sun ◽  
Yuzhen Liang ◽  
Zhengming Li ◽  
Ning Xia
Keyword(s):  
Signaling Pathway ◽  
Osteoblastic Differentiation ◽  
Control Group ◽  
Activity Levels ◽  
Expression Levels ◽  
Protein Levels ◽  
Proliferation And Differentiation ◽  
Glucagon Like Peptide 1 ◽  
Differentiation And Proliferation

Liraglutide is a glucagon-like peptide-1 analogue widely used in the treatment of type 2 diabetes mellitus. However, the effects of liraglutide on osteoblast proliferation and differentiation in MC3T3-E1 cells have not been fully elucidated. In the present study, the promoting effects of liraglutide were investigated in MC3T3-E1 cells. The results indicated that cell viability was affected following the treatment of the cells with different concentrations of liraglutide (0, 10, 100, and 1000 nM) at different time periods of culture (24, 48, and 72 h). Moreover, the activity levels of alkaline phosphatase and the number of mineralized nodules in MC3T3-E1 cells were significantly increased following treatment with 100 nM liraglutide. The mRNA and protein levels of Col-1, OPG, and OCN in MC3T3-E1 cells were also markedly increased following 100 nM liraglutide treatment compared with those of the control group. The expression levels of the ERK5 signaling pathway key proteins (MEK5, p-ERK5, ERK5, and NUR77) were increased following liraglutide treatment in MC3T3-E1 cells, and the gene expression levels of the ERK5 signaling pathway were also elevated. Moreover, the ERK5 inhibitor XMD8-92 significantly decreased the expression levels of p-ERK5 and NUR77 as well as the proliferation of osteoblasts. However, these changes could be rescued by liraglutide to some extent. Therefore, these results revealed that liraglutide may promote osteoblastic differentiation and proliferation in MC3T3-E1 cells via the activation of the ERK5 signaling pathway.

scholarly journals Moxibustion Inhibits the ERK Signaling Pathway and Intestinal Fibrosis in Rats with Crohn’s Disease

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Xiaomei Wang ◽  
Yuan Lu ◽  
Luyi Wu ◽  
Chen Zhao ◽  
Chunbin Song ◽  
...  
Keyword(s):  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Signaling Pathway ◽  
Pathological Process ◽  
Erk Signaling ◽  
Control Group ◽  
Mrna Levels ◽  
Colon Tissue ◽  
Intestinal Fibrosis ◽  
Mild Moxibustion

Intestinal fibrosis is the main pathological process in Crohn’s disease (CD); acupuncture and moxibustion can inhibit the process of fibrosis in CD rats, but the regulatory mechanism remains unknown. The present study observed the effect of moxibustion on the extracellular signal-regulated kinase (ERK) signaling pathway in the CD rat. The result shows that the phosphorylation of the Ras, Raf-1, MEK-1, and ERK-1/2 proteins and the expression of the corresponding mRNAs in the colon tissue of CD rat were significantly higher than the normal control group. Both treatments with mild moxibustion and with herb-separated moxibustion significantly reduced the expression of the Ras, Raf-1, MEK-1, and ERK-1/2 proteins and Ras and Raf-1 mRNA. MEK-1 and ERK-1/2 mRNA expression in each treatment group showed a downward trend, and the ERK-1/2 mRNA levels were significantly lower in the mild moxibustion group. It indicates that Ras, Raf-1, MEK-1, and ERK-1/2 are involved in the process of intestinal fibrosis in CD rats. Moxibustion can downregulate the abnormal expression of colonic Ras, Raf-1, MEK-1, and ERK-1/2 protein and mRNA levels in CD intestinal fibrosis in rats. Moxibustion may play a role in the treatment of CD intestinal fibrosis by regulating ERK signaling pathway.

Scutellarin Attenuates Human-Neutrophil-Elastase-Induced Mucus Production by Inhibiting the PKC-ERK Signaling Pathway in Vitro and in Vivo

2011 ◽  
Vol 39 (06) ◽  
pp. 1193-1206 ◽  
Author(s):  
De-Peng Jiang ◽  
Qi Li ◽  
Jie Yang ◽  
Juliy M. Perelman ◽  
Victor P. Kolosov ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Neutrophil Elastase ◽  
Human Neutrophil ◽  
Erk Signaling ◽  
Control Group ◽  
Human Neutrophil Elastase ◽  
Dependent Manner ◽  
Mucus Production

The aim of this study was to investigate the influence of scutellarin on mucus production induced by human neutrophil elastase (HNE) and the possible in vitro and in vivo mechanisms. To this purpose, cells were incubated with saline, scutellarin or gefitinib for 60 min and exposed to 0.1 μM HNE for 24 h. After being pretreated respectively with saline, scutellarin or gefitinib, rats were challenged intratracheally with HNE by means of nebulization for 30 days. The expression of mucin (MUC) 5AC, protein kinase C (PKC), and extracellular signal-regulated kinase 1/2 (ERK1/2) was assessed by ELISA, RT-PCR or Western blotting. The results showed that scutellarin inhibited MUC5AC mRNA and protein expressions induced by HNE in a concentration-dependent manner in vitro. In the in vivo model, scutellarin significantly attenuated MUC5AC mRNA expression and goblet cell hyperplasia in rats treated with HNE for 30 days, as well as decreased the phosporylation of PKC and ERK1/2 compared to the HNE control group. Therefore, our study showed that scutellarin could prevent mucus hypersecretion by inhibiting the PKC-ERK signaling pathway. Inhalation scutellarin may be valuable in the treatment of chronic inflammatory lung disease.

Vaspin attenuates the apoptosis of human osteoblasts through ERK signaling pathway

Amino Acids ◽  
2012 ◽  
Vol 44 (3) ◽  
pp. 961-968 ◽  
Author(s):  
Xiao Zhu ◽  
Yi Jiang ◽  
Peng-Fei Shan ◽  
Jie Shen ◽  
Qiu-Hua Liang ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Erk Signaling ◽  
Human Osteoblasts

scholarly journals EspH Suppresses Erk by Spatial Segregation from CD81 Tetraspanin Microdomains

2018 ◽  
Vol 86 (10) ◽  
Author(s):  
Rachana Pattani Ramachandran ◽  
Felipe Vences-Catalán ◽  
Dan Wiseman ◽  
Efrat Zlotkin-Rivkin ◽  
Eyal Shteyer ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Inhibitory Effect ◽  
Effector Proteins ◽  
Mitogen Activated Protein Kinase ◽  
Erk Signaling ◽  
Human Pathogens ◽  
Necrosis Factor Alpha ◽  
Content Type ◽  
C Terminus ◽  
Tnf Α

ABSTRACT Enteropathogenic Escherichia coli (EPEC) belongs to a group of enteric human pathogens known as attaching-and-effacing (A/E) pathogens, which utilize a type III secretion system (T3SS) to translocate a battery of effector proteins from their own cytoplasm into host intestinal epithelial cells. Here we identified EspH to be an effector that prompts the recruitment of the tetraspanin CD81 to infection sites. EspH was also shown to be an effector that suppresses the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (Erk) signaling pathway at longer infection times. The inhibitory effect was abrogated upon deletion of the last 38 amino acids located at the C terminus of the protein. The efficacy of EspH-dependent Erk suppression was higher in CD81-deficient cells, suggesting that CD81 may act as a positive regulator of Erk, counteracting Erk suppression by EspH. EspH was found within CD81 microdomains soon after infection but was largely excluded from these domains at a later time. Based on our results, we propose a mechanism whereby CD81 is initially recruited to infection sites in response to EspH translocation. At a later stage, EspH moves out of the CD81 clusters to facilitate effective Erk inhibition. Moreover, EspH selectively inhibits the tumor necrosis factor alpha (TNF-α)-induced Erk signaling pathway. Since Erk and TNF-α have been implicated in innate immunity and cell survival, our studies suggest a novel mechanism by which EPEC suppresses these processes to promote its own colonization and survival in the infected gut.

scholarly journals IL-38 restrains inflammatory response of collagen-induced arthritis in rats via SIRT1/HIF-1α signaling pathway

2020 ◽  
Vol 40 (5) ◽  
Author(s):  
Bing Pei ◽  
Keyan Chen ◽  
Shenglai Zhou ◽  
Dongyu Min ◽  
Weiguo Xiao
Keyword(s):  
Inflammatory Response ◽  
Signaling Pathway ◽  
Joint Damage ◽  
Inhibitory Effect ◽  
Angiogenic Factor ◽  
Inflammatory Factors ◽  
Control Group ◽  
Collagen Induced Arthritis ◽  
Related Proteins

Abstract Objective: To observe the restraining effect of IL-38 on inflammatory response in collagen-induced arthritis rats (CIA), and to explore the regulatory mechanism of SIRT1/HIF-1α signaling pathway. Methods: 40 SD rats were randomly divided into Control group, CIA group, CLL group and CLH group, with 10 rats in each group; CIA rat model was established. The effects of IL-38 on arthritis index, inflammatory response, osteogenic factor and angiogenic factor were observed by methods including HE staining, ELISA, immunohistochemical and immunofluorescence. Human synoviocytes were cultured in vitro, and SIRT1 inhibitors were added to detect the expression for relating factors of SIRT1/HIF-1α signaling pathway by Western blot. Results: IL-38 could alleviate CIA joint damage and restrain inflammatory response, could up-regulate the expression of OPG in CIA rats and could down-regulate the expression of RANKL and RANK. IL-38 could restrain the expression of VEGF, VEGFR1, VEGFR2 and HIF. Moreover, we found that IL-38 could up-regulate the SIRT1 expression and down-regulate the HIF-1α, TLR4 and NF-KB p65 expression in CLL and CLH groups. From the treatment of synoviocytes to simulate the CIA model and the treatment of SIRT1 inhibitors, we demonstrated that the inhibitory effect of IL-38 on inflammatory factors and regulation of SIRT1/HIF-1α signaling pathway-related proteins were inhibited. Conclusion: IL-38 can restrain the inflammatory response of CIA rats, can promote the expression of osteogenic factors, can inhibit neovascularization, and can alleviate joint damage in rats. The mechanism may be related to the regulation of SIRT1/HIF-1α signaling pathway.

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