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Objective To investigate the effect and mechanism of acteoside (ACT) in inhibiting epithelial-mesenchymal transition (EMT) in human hepatoma HCCLM3 cells by regulating the ERK1/2 pathway. Methods CCK-8 assay was used to detect the effect of hepatocellular carcinoma cell proliferation. The invasion and migration of HCC cells were detected by scratch and Transwell tests. The mRNA and protein expression levels of the ERK1/2 signaling pathway and EMT-related genes (E-cadherin and N-cadherin) were detected by real-time PCR and Western blot analyses. Results ACT reduced the activity of HCCLM3 cells and inhibited the proliferation of HCC cells, and the effects had certain correlation with drug concentration and time. ACT inhibited the migration and invasion process of HCCLM3 cells in a concentration-dependent manner. ACT downregulated the mRNA and protein expression of genes related to the ERK1/2 signaling pathway. It increased the mRNA and protein expression levels of the EMT-related gene E-cadherin but decreased those of N-cadherin. Conclusion ACT could inhibit EMT and the invasion and migration of HCCLM3 cells in human hepatoma, and the underlying mechanism is closely related to the downregulation of the ERK1/2 signaling pathway.
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Abstract Bone morphogenetic protein-4 (BMP4) is a member of the bone morphogenetic protein family which plays an important role in bone formation, inflammation and cardiac hypertrophy. The aim of this study was to investigate the underlying molecular mechanism that BMP4-induced cardiomyocyte hypertrophy. H9c2 cells were used to measure cell surface area and protein synthesis. Western blot was used to examine hypertrophic marker brain natriuretic peptide (BNP) protein expression and phosphorylation of ERK1/2. The results exhibited that cell surface area, protein synthesis and BNP protein expression were increased with BMP4 treatment. While PD98059 inhibited these effects of BMP4. In addition, BMP4 treatment increased phosphorylation of ERK1/2 in a time- and dose-dependent manner. PD98059 treatment decreased phosphorylation of ERK1/2 that was increased by BMP4. These results suggest that BMP4 induces cardiomyocyte hypertrophy through the activation of ERK1/2 cell signaling pathway.
Subject(s)
Cardiomegaly/chemically induced , Bone Morphogenetic Protein 4/administration & dosage , Blotting, Western/instrumentation , Mitogen-Activated Protein Kinase 3 , Wnt Signaling PathwayABSTRACT
Objective To study the effects of osteopontin (OPN) on the nuclear mechanics of bone marrow-derived mesenchymal stem cells (BMSCs) as well as its involved mechanisms. Methods The BMSC migration was evaluated using the Transwell assay. An atomic force microscope (AFM) was used to determine the elastic modulus of the BMSC nucleus and analyze the changes in the nuclear mechanics of the BMSCs after treatment with OPN. The activation of focal adhesion kinase (FAK) and extracellular signal-regulated kinase1/2 (ERK1/2) was measured by Western blot. The role of the FAK-ERK1/2 signaling pathway in mediating the OPN-affected BMSC nuclear mechanics was investigated by employing a specific inhibitor. RT-PCR and Western blot were used to detect the expression of Lamin A/C at mRNA and protein levels in the BMSCs, respectively. Results The elastic modulus of the BMSC nucleus exhibited a significant decrease after OPN treatment compared with that of the control group. OPN could upregulate the phosphorylation level of FAK and ERK1/2, but the inhibitor of FAK or ERK1/2 restored the OPN-decreased elastic modulus of the BMSC nucleus and inhibited the BMSC migration significantly. After treatment with OPN, the expression of Lamin A/C in the BMSCs reduced significantly, and such a reduced expression could be suppressed by the inhibitor of FAK or ERK1/2. Conclusions OPN could probably downregulate the expression of Lamin A/C of the BMSCs via the FAK-ERK1/2 signaling pathway, decrease the stiffness of the BMSC nucleus, and promote the migration of the BMSCs. The research outcomes provide the experimental evidence for further understanding the mechanism of the OPN-regulated BMSC migration and its potential clinical application.
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To clarify the effects of Zuoguiwan containing serum on osteoblast proliferation and alkaline phosphatase(ALP) expression and its effects on the expression of β-catenin, ERK1, ERK2 mRNA and protein of osteoblast through ERK1/2, Wnt/β-catenin signaling pathway in models with osteoporosis(OP) kidney-Yang-deficiency, osteoporosis(OP) kidney-Yin-deficiency syndrome. Rat osteoporosis models were established by ovariectomy surgery, and 10 weeks after surgery, hydrocortisone was injected and thyroxine was administered by intragastric administration to establish OP kidney-Yang-deficiency rat model, and OP kidney-Yin-deficiency rat model. Osteoblasts were obtained from 24 h newborn rat skull and were identified by alkaline phosphatase and alizarin red staining. Zuoguiwan containing serum of OP, OP kidney-Yang-deficiency, and OP kidney-Yin-deficiency, as well as the blank serum were used to intervene the osteoblast, and the cells proliferation was detected by MTS. ELISA assay was used to detect ALP expression. RT-PCR assay was used to detect the mRNA expression of ERK1, ERK2, β-catenin and protein expression levels were detected by Western blot. The results showed that Zuoguiwan containing serum in OP kidney-Yin-deficiency model had stronger effect than OP kidney-Yang-deficiency in promoting osteoblast proliferation, ALP expression, osteoblast ERK1/2, Wnt/β-catenin signaling pathway related factors β-catenin, ERK1, ERK2 mRNA and protein expression levels. This was consistent with the TCM theory of "Zuoguiwan nourishes kidney Yin", providing a scientific basis for the clinical and dialectical treatment of osteoporosis. Zuoguiwan could regulate the proliferation and differentiation of bone cells by ERK1/2 and Wnt/β-catenin signaling pathway, which may be one of the mechanisms of Zuoguiwan for the prevention of osteoporosis.
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Objective To explore the neuroprotection and mechanisms of bone marrow mononuclear cells (BMMNCs),and evaluate whether ERK1/2 signaling pathway was involved in it.Methods384 healthy male SD rats,which were 6-8 week old,weighting 250-280 g,were selected.The middle cerebral artery occlusion (MCAO) model was established in SD rats using the suture method.The rats were randomly divided into sham operation group,model group,BMMNCs group and ERK1/2 inhibitor group,with 96 rats in each group.At the time of 24 h after the successful modeling,200 μl PBS solution was injected into the caudal vein of the rats in the model group,200 μl PBS solution containing 5×106 BMMNCs was injected into the rats in the BMMNCs group and the ERK1/2 inhibitor group.meanwhile,5 μl PD98059 was injected into the lateral ventricle of the brain of rats in the ERK1/2 inhibitor group.At the time points of 3 d,7 d and 14 d,the modified neurological severity scores (mNSS) was used to evaluate the neurological function,the volume of cerebral infarction was assessed by TTC staining,the pERK1/2,Bax,Bcl-2 and caspase-3 levels were detected by Western blot,and the effect of BMMNCs on activation of microglia was detected by immunofluorescence assay.Results(1)At each time point,the mNSS and the volume of cerebral infarction of the model group were significantly higher than those of the sham operation group (P0.05).(2)At each time point,the pERK1/2,Bcl-2,Bax and caspase-3 protein levels of the model group were significantly higher than those of the sham operation group (P0.05).(3) At each time point,microglia (Iba1 positive) in ischemic penumbra of the BMMNCs group was significantly more than those of the model group,and it was increased with the time extension (P0.05).ConclusionBMMNCs can reduce the apoptosis through ERK1/2 signaling pathway,thus improving the neurological function and reducing the infarct scope.
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Objective To further investigate direct effects of dipeptidyl peptidase-4(DPP4) on calcification and to identify responsible signaling pathways in human vascular smooth muscle cells (HVSMC). Methods The effect of DPP-4 on calcification of HVSMC was observed by alizarin red, and Western blot was used to detect whether DPP4 induced calcification-related protein expressions through extracellular signal-regulated kinases 1/2 (ERK1/2) pathway. Results The Alizarin red staining results showed that calcified nodules in DPP4 group were significantly increased as compared with control group, similar to calcification group.The protein expressions of osteoprotegerin (OPG), osteopontin (OPN), Runt-related transcription factor 2 (RUNX2), and bone morphogenetic protein 2 (BMP2) were stimulated by DPP4 in a concentration- and time-dependent manner. The phosphorylation level of ERK1/2 was significantly increased after DPP4 incubation for 15 min (P<0.05). PD98059, an ERK1/2 inhibitor, significantly lowered DPP4-stimulated expressions of calcification-related proteins (P<0.05). Conclusion DPP4 may promote the calcification of HVSMC through ERK1/2 signaling pathways.
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Aim To investigate the protective effect of allicin against EA. hy926 endothelial cell injury in-duced by PM2. 5 and the possible mechanism. Meth-ods The samples of fine particulate matter ( PM2. 5 ) were collected and made into suspension. Different concentrations of PM2. 5 ( 20 , 200 , 400 mg · L-1 ) were added to EA. hy926 cell. The viability and apop-tosis of EA. hy926 cell, the protein levels of p-ERK1/2, Bax and Bcl-2 in the EA. hy926 cell, the contents of tumor necrosis factor-α( TNF-α) , interleukin-6 ( IL-6 ) , and malonaldehyde ( MDA ) , the activities of su-peroxide dismutase ( SOD ) and lactic dehydrogenase ( LDH) in the EA. hy926 cell culture supernatant were measured by MTT assay, flow cytometry, Western blot, enzyme-linked immunosorbent assay ( ELISA ) and colorimetry, respectively. Allicin at different con-centrations(5,20,40 mg·L-1 ) or a specific inhibitor of ERK1/2 signaling pathway PD98059 ( 20 μmol · L-1 ) was added into the EA. hy926 cell to observe the effect of allicin. Results Compared with control group, PM2. 5 significantly increased the apoptosis, the contents of TNF-α, IL-6 and MDA, the activity of LDH, the protein levels of p-ERK1/2 and Bax/Bcl-2 ratio, but decreased the viability and SOD activity in the EA. hy926 cell(P<0. 05). Compared with PM2. 5 group, allicin significantly decreased the apoptosis, the contents of TNF-α, IL-6 and MDA, the activity of LDH, the protein levels of p-ERK1/2 and Bax/Bcl-2 ratio, but increased the viability and SOD activity in the EA. hy926 cell ( P <0. 05 ) . Conclusion Allicin displays a significant protective effect against EA. hy926 endothelial cell injury induced by PM2 . 5 and its mechanism may be related to the attenuations of in-flammation and oxidative stress via the inhibition of ERK1/2 pathway.
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Objective To investigate the effect of mitogen activated protein kinase / extracellular signal-regulated kinase (MEK / ERK)1 / 2 signaling pathway on early brain injury (EBI)following experimental subarachnoid hemorrhage (SAH)in rats. Methods Sixty male SD rats were randomly divided into a control group and a 1,6,12,24,48,or 72 h group after SAH modeling. SAH + MEK inhibitor U0126 was used to intervene the 24,48,and 72 h groups (a total of 10 groups;n = 6 in each group). In addition to the control group,blood was injected into the cisterna magna of the rats to induce a SAH model in another 9groups. The blood samples were taken from infraorbital venous plexus. Enzyme-linked immune sorbent assay (ELISA)was used to detect the levels of interleukin-6 (IL-6),IL-1β,and tumor necrosis factor α(TNF-α)in each group. Evans blue content in brain tissue was used to evaluate the blood-brain barrier damage. Western blot was used to detect the levels of phosphorylated extracellular signal-regulated kinase (p-ERK1/ 2)and matrix metalloproteinase-9 (MMP-9)proteins in basilar artery tissue,and compared them. Results Compared with the control group at the same time points,there were significant differences in the levels of IL-6 and IL-1β at 6,12,24,48,and 72h after modeling in the SAH group (all P <0. 05). At 12,24, 48,and 72 h after modeling,the expression levels of p-ERK1/ 2 protein of the basilar artery tissue of the SAH group were 0. 73 ± 0. 09,0. 85 ± 0. 12,0. 94 ± 0. 09,and 0. 96 ± 0. 09,respectively,they were significantly higher than those of the control group (all P < 0. 05). At 48 and 72 h after modeling in the SAH group,the level of MMP-9 protein was significantly higher than that in the control group (1. 27 ± 0. 15 vs. 0. 68 ± 0. 08,2. 41 ± 0. 11 vs. 0. 71 ± 0. 14). At 72 h after modeling,the Evans blue content in brain tissue of the SAH group was significantly higher than that of the control group (15. 3 ± 2. 2 μg/ g vs. 2. 7 ± 0. 4 μg/ g). After giving the MEK inhibitor U0126 intervention,the levels of serum IL-6,IL-1β,and TNF-α at 24,48, and 72 h after modeling,and the expression levels of p-ERK1 / 2 and MMP-9 proteins at 48 and 72 h (p-ERK1 / 2:0. 76 ± 0. 07,0. 81 ± 0. 06;MMP-9:0. 92 ± 0. 14,1. 79 ± 0. 16),and the Evans blue content (8. 9 ± 1. 7 μg / g)in brain tissue at 72 h after modeling were significantly lower than those of the SAH group (P < 0. 05). Conclusion The MEK/ ERK1/ 2 signal pathway may be closely associated with the inflammatory reaction and blood-brain barrier damage after SAH,which suggests that the intervention of the MEK/ ERK1 / 2 signal pathway may be a potential target for the prevention of early brain injury after SAH.
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Objective To investigate the inhibitory effect and associated mechanism of rapamycin on proliferation and extracellular matrix (ECM) secretion in myofibroblasts stimulated by connective tissue growth factor (CTGF). Methods Primary cultivated myofibroblasts were divided into 6 groups: control, CTGF (100 μg/L), rapamycin 20 μg/L+CTGF 100 μg/L, rapamycin 40 μg/L +CTGF 100 μg/L, rapamycin 20 μg/L, and rapamycin 40 μg/L alone. 5'-bromodeoxyuridine (BrdU) incorporation assay was used to detect the myofibroblast proliferation.Western blot was used to analysis the secretory FN protein in the supernatant medium of cultured myofibroblasts and the ERK1/2 phosphorylation in myofibroblasts. Results CTGF (100 μg/L)incubation significantly increased the number of Brdu positive myofibroblasts(P<0.01) and the level of FN protein secretory (P<0.05) in cell supernatant medium compared with control group,respectively. The number of Brdu positive myofibroblasts markedly decreased by 62% and 70% (P <0.05) in rapamycin 20 μg/L+CTGF 100 μg/L and rapamycin 40 μg/L+CTGF 100 μg/L groups, respectively. The FN protein levels in supernatant were decreased by 15% and 44% compared with CTGF 100 μg/L group, respectively; but the difference of FN protein levels was significant only in rapamycin 40 μg/L group (P<0.05). CTGF could activate ERK1/2 at 10 minutes; but as myofibroblasts were pretreated with rapamycin 40 μg/L for 30 min, it abolished CTGF-induced ERK1/2 phosphoralation. PD98059, the specific inhibitor of ERK1/2, could block the effect of CTGF-induced proliferation (7%±5% vs 85%±7%, P<0.01) and FN secretion (1.0±0.1 vs 1.6±0.3, P<0.05). Conclusions Rapamycin partially suppresses the proliferation and ECM secretion of myofibroblasts induced by CTGF. Its effect may be through inhibiting CTGF-induced activation of ERKI/2 signaling pathway.