Expression of Extracellular Signal-regulated Kinase and Angiotensin-converting Enzyme in Human Atria during Atrial Fibrillation

In order to investigate the changes in the expression of extracellular signal regulated kinase (ERK1/ERK2) and angiotensin converting enzyme (ACE) in the patients with atrial fibrillation (AF), 52 patients with rheumatic heart diseases were examined. Nineteen patients had chronic persistent AF (AF≥6 months, CAF), 12 patients had paroxymal AF (PAF) and 21 patients had no history of AF. The ERK expression was detected at the mRNA level by reverse transcription polymerase chain reaction, at the protein level by Western blotting and at atrial tissue level by immunohistochemistry. ERK activating kinases (MEK1/2) and ACE were determined by Western blotting techniques. The expression of ERK2 mRNA was increased in the patients with CAF (74±19 U vs sinus rhythm: 32±24 U, P <0.05). Activated ERK1/ERK2 and MEK1/2 were increased to more than 150 % in the patients with AF compared to those with sinus rhythm. No significant difference between CAF and PAF was found. The expression of ACE was three fold increased in the patients with CAF compared to those with sinus rhythm. Patients with AF showed an increased expression of ERK1/ERK2 in atrial interstitial cells and marked atrial fibrosis. An ACE dependent increase in the amounts of activated ERK1/ERK2 in atrial interstitial cells may be one of molecular mechanisms for the development of atrial fibrosis in the patients with AF. These findings may have important impact on the treatment of AF.

Optimized new Shengmai powder(优化新生脉散方) inhibits myocardial fibrosis in heart failure by regulating the rat sarcoma/rapidly accelerated fibrosarcoma/mitogen-activated protein kinase kinase/extracellular regulated protein kinases signaling pathway

OBJECTIVE: Exploring the effect of Optimized New Shengmai powder(优化新生脉散方, ONSMP) on myocardial fibrosis in heart failure(HF) based on rat sarcoma(RAS)/rapidly accelerated fibrosarcoma(RAF)/mitogen-activated protein kinase kinase(MEK)/extracellular regulated protein kinases(ERK) signaling pathway. METHODS: Randomized 70 Sprague-Dawley rats into sham(n = 10) and operation(n = 60) groups, then established the HF rat by ligating the left anterior descending branch of the coronary artery. We randomly divided the operation group rats into the model, ONSMP [including low(L), medium(M), and high(H) dose], and enalapril groups. After the 4-week drug intervention, echocardiography examines the cardiac function and calculates the ratios of the whole/left heart to the rat's body weight. Finally, we observed the degree of myocardial fibrosis by pathological sections, determined myocardium collagen(COL) Ⅰ and COL Ⅲ content by enzyme-linked immunosorbent assay, detected the m RNA levels of COL Ⅰ, COL Ⅲ, α-smooth muscle actin(α-SMA), and c-Fos proto-oncogene(c-Fos) by universal real-time, and detected the protein expression of p-RAS, p-RAF, p-MEK1/2, p-ERK1/2, p-ETS-like-1 transcription factor(p-ELK1), p-c-Fos, α-SMA, COL Ⅰ, and COL Ⅲ by Western blot. RESULTS: ONSMP can effectively improve HF rat's cardiac function, decrease cardiac organ coefficient, COL volume fraction, and COL Ⅰ/Ⅲ content, down-regulate the m RNA of COL Ⅰ/Ⅲ, α-SMA and c-Fos, and the protein of p-RAS, p-RAF, p-MEK1/2, p-ERK1/2, p-ELK1, c-Fos, COL Ⅰ/Ⅲ, and α-SMA. CONCLUSIONS: ONSMP can effectively reduce myocardial fibrosis in HF rats, and the mechanism may be related to the inhibition of the RAS/RAF/MEK/ERK signaling pathway.

ROLE OF ERK1/2 KINASE IN CISPLATIN-INDUCED APOPTOSIS IN HUMAN OVARIAN CARCINOMA CELLS

Objective To investigate the role of extracellular regulated kinase (ERK1/2) pathway in cisplatin-induced apoptosis in human ovarian carcinoma cells. Methods Cisplatin-induced apoptosis were stained with DAPI and was assessed microscopically in human epithelial adenocarcinoma ovarian cell line SKOV3 cells. ERK activation was determined by Western blotting using an anti-phospho-ERK antibody to detect ERK activity. The effect of PD98059 on ERK activity induced by cisplatin was detected by MTT assay. Results Marked apoptosis of SKOV3 cells resulted from 48 hours treatment with 20 μg/mL cisplatin. Strong activation of ERK was led to by 15 μg/mL cisplatin. Dose response and time course of cisplatin induced apoptosis in SKOV3 cells. Cisplatin-induced ERK activation occurred at 12 hours and increased to highest induction at 24 hours by Western blotting. The effect of PD 98059 on ERK activity induced by cisplatin at the concentration of 100 μmol/L PD 98059. Statistically significant decreased in cell survival were observed with 100 μmol/L PD 98059 at 15 and 20 μg/mL cisplatin (P< 0.05). Conclusions Cisplatin activates the ERK signaling pathway in ovarian cancer cell line SKOV3. Inhibition of ERK acti-vity enhances sensitivity to cisplatin cytotoxity in ovarian cancer cell line SKOV3. Evaluation of ERK activity could be useful in predicting which ovarian cancer will response most favorably to cisplatin therapy.

Sphingosine-1-Phosphate Protects Against the Development of Cardiac Remodeling via Sphingosine Kinase 2 and the S1PR2/ERK Pathway

Objective:Cardiac remodeling is a common pathological change in various cardiovascular diseases and can ultimately result in heart failure.Thus,there is an urgent need for more effective strategies to aid in cardiac protection.Our previous work found that sphingosine-1-phosphate(S1P)could ameliorate cardiac hypertrophy.In this study,we aimed to investigate whether S1P could prevent cardiac fibrosis and the associated mechanisms in cardiac remodeling.Methods:Eight-week-old male C57BL/6 mice were randomly divided into a sham,transverse aortic constriction(TAC)or a TAC+S1P treatment group.Results:We found that S1P treatment improved cardiac function in TAC mice and that the cardiac fibrosis ratio in the TAC+S1P group was significantly lower and was accompanied by a decrease inα-smooth muscle actin(α-SMA)and collagen type I(COL I)expression compared with the TAC group.We also found that one of the key S1P enzymes,sphingosine kinase 2(SphK2),which was mainly distributed in cytoblasts,was downregulated in the cardiac remodeling case and recovered after S1P treatment in vivo and in vitro.In addition,our in vitro results showed that S1P treatment activated extracellular regulated protein kinases(ERK)phosphorylation mainly through the S1P receptor 2(S1PR2)and spurred p-ERK transposition from the cytoplasm to cytoblast in H9c2 cells exposed to phenylephrine.Conclusion:These findings suggest that SphK2 and the S1PR2/ERK pathway may participate in the anti-remodeling effect of S1P on the heart.This work therefore uncovers a novel potential therapy for the prevention of cardiac remodeling.

Study on Effects of Extracts from Salvia Miltiorrhiza and Curcuma Longa in Inhibiting Phosphorylated Extracellular Signal Regulated Kinase Expression in Rat's Hepatic Stellate Cells

Objective： To study the effect of salvianolic acid B （SAB） and curcumin, the extracts of Solvie Miltiorrhize and Curcume Longe, on the proliferation and activation of hepatic stellate cell （HSC）, and the extracellular signal regulated kinase （ERK） expression in it. Methods： Rat＇s HSC-T6 were cultured and treated by SAB or curcumin. The inhibitory effect on cell proliferation was determined by 3-（4,5-dimthyl-2- 2thiazoly）-2,5-diphenyl-2H-tetrazolium bromide （MTT） colorimetry, and the expression levels of a smooth actin （a-SMA）, collagen type Ⅰ , and ERK were determined by Western blot. Results： SAB and curcumin inhibited the proliferation and activation of rat＇s HSC-T6 in dose-dependent fashion and significantly reduced the expression level of a-SMA （ P〈0.01 ）. Curcumin significantly reduced the expression of collagen type Ⅰ （P〈0.05）. Both SAB and curcumin showed insignificant effect on the ERK expression level, but they could significantly reduce the level of phosphorylated-ERK expression, showing significant difference as compared with that in the control group （ P〈0.01 and P〈0.05 respectively）. Conclusion： SAB and curcumin could significantly inhibit the proliferation, activation of HSC, and the production of type Ⅰ collagen in HSC, the mechanism may be associated with their inhibition on ERK phosphorylation.

Shenmai Injection(参麦注射液) Inhibiting the Extracellular Signal Regulated Kinase-lnduced Human Airway Smooth Muscle Proliferation in Asthma

Objective： To investigate the relationship between the proliferation of sensitized human airway smooth muscle cells （HASMCs） and the expression of extracellular signal regulated kinase （ERK） and the effect of Shenmai Injection （参麦注射液, SMI） on HASMCs. Methods： The HASMCs cultured in vitro were divided into three groups： （1） control group; （2） sensitized group： containing 10% asthmatic serum; （3） SMI group： further divided into three different concentration subgroups interferred with 10 μL/mL, 50 μL/mL, and 100 μL/mL SMI, respectively. The proliferation of HASMCs was detected using MTT method, the expression of proliferating cell nucleus antigen （PCNA） in HASMCs was detected using immunocytochemical staining, and the expression of phosphoration-ERK1/2 （p-ERK1/2） protein was detected using Western-blot. Results： After passive sensitization, the optical density value （A49o value） of HASMCs was significantly increased from 0.366± 0.086 to 0.839 ± 0.168 （P〈0.05）. In addition, the expression of PCNA was significantly increased from 28.7% ± 5.9% in the control group to 69.8% ±7.5% in the sensitized group （P〈0.05）. At the same time, the expression of p-ERK1/2 in passively sensitized HASMCs was significantly increased compared with the control group （all P〈0.05）. Affer application of 10 μL/mL, 50 μL/mL, and 100 μL/mL SMI to the cultured media of passively sensitized group, the A570 value was significantly decreased from 0.839 ±0.168 to 0.612 ±0.100, 0.412 ± 0.092, and 0.339 ± 0.077, respectively （P〈0.05）. Moreover, the expression of PCNA was significantly decreased from 69.8% ±7.5% to 57.8% ± 6.2%, 40.7%±5.4%, and 26.1% ± 5.2%, respectively. At the same time, the expression of p-ERK1/2 in each SMI group was significantly decreased compared with the sensitized group （all ,P〈0.05）. Conclusion： ERK signal transduction pathway may be involved in the airway remodeling in asthma. The expression of ERK can be inhibited by SMI in a dose-dependent manner, thus preventing the proliferation of HASMCs.

Topical dihydroartemisinin inhibits suture-induced neovascularization in rat corneas through ERK1/2 and p38 pathways

AIM: To determine if topical instillation of dihydroartemisinin (DHA) inhibits corneal neovascularization (NV) in rats and to investigate the role of the extracellular regulated kinases (ERK) 1/2 and p38 pathways in this process. O METHODS: Suture-induced corneal NV was produced in rats and the eyes were topically treated with different concentrations of DHA (20mg/L, 10mg/L or 5mg/L) or normal saline 4 times a day for 7 days. The corneal NV was quantified as the proportion of NV area to the whole cornea. Western blot was used to determine the expressions of vascular endothelial growth factor (VEGF) and the phosphorylation status of VEGF receptor-2, ERK1/2 and p38 in the corneas. Immunofluorescent staining was used to determine the expressions of phospho-ERK1/2 and phospho-p38 in the corneal tissues from the eyes treated with 20 mg/L DHA (DHA group) or normal saline (control group). RESULTS: The proportion of corneal NV area in the eyes treated with normal saline or DHA at dosages of 20mg/L, 10mg/L or 5mg/L was (23.74 +/- 3.00)%, (15.73 +/- 2.88)%, (19.53 +/- 2.42)%, and (23.38 +/- 2.79)%, respectively. In the eyes treated with 20mg/L or 10mg/L DHA, the corneal NV area was significantly reduced when compared to that in eyes with normal saline (P < 0.05). Western blot analyses revealed that 20mg/L DHA significantly inhibited the expressions of VEGF and phospho-VEGFR-2. Both 20mg/L and 10mg/L DHA inhibited the expressions of phospho-ERK1/2 and phospho-p38. Immunofluorescent staining further demonstrated that 20mg/L DHA lowered the Expression levels of phospho-ERK1/2 and phospho-p38 in the corneas with suture-induced NV. O CONCLUSION: Suture-induced NV in rat corneas was significantly inhibited by topical treatment with 20mg/L and 10mg/L DHA. The results suggest that the effects could be partially dependent on the DHA-mediated inhibitions of the ERK1/2 and p38 pathways.

Correlation between receptor-interacting protein 140 expression and directed differentiation of human embryonic stem cells into neural stem cells

Overexpression of receptor-interacting protein 140（RIP140） promotes neuronal differentiation of N2 a cells via extracellular regulated kinase 1/2（ERK1/2） signaling.However,involvement of RIP140 in human neural differentiation remains unclear.We found both RIP140 and ERK1/2 expression increased during neural differentiation of H1 human embryonic stem cells.Moreover,RIP140 negatively correlated with stem cell markers Oct4 and Sox2 during early stages of neural differentiation,and positively correlated with the neural stem cell marker Nestin during later stages.Thus,ERK1/2 signaling may provide the molecular mechanism by which RIP140 takes part in neural differentiation to eventually affect the number of neurons produced.

TRAIL-induced apoptosis of hepatocellular carcinoma cells is augmented by targeted therapies

AIM:To analyze the effect of chemotherapeutic drugs and specific kinase inhibitors,in combination with the death receptor ligand tumor necrosis factor-related apoptosis inducing ligand(TRAIL),on overcoming TRAIL resistance in hepatocellular carcinoma(HCC)and to study the efficacy of agonistic TRAIL antibodies,as well as the commitment of antiapoptotic BCL-2 proteins, in TRAIL-induced apoptosis. METHODS:Surface expression of TRAIL receptors (TRAIL-R1-4)and expression levels of the antiapoptotic BCL-2 proteins MCL-1 and BCL-xL were analyzed by flow cytometry and Western blotting,respectively. Knock-down of MCL-1 and BCL-xL was performed by transfecting specific small interfering RNAs.HCC cellswere treated with kinase inhibitors and chemotherapeutic drugs.Apoptosis induction and cell viability were analyzed via flow cytometry and 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. RESULTS:TRAIL-R1 and-R2 were profoundly expressed on the HCC cell lines Huh7 and Hep-G2. However,treatment of Huh7 and Hep-G2 with TRAIL and agonistic antibodies only induced minor apoptosis rates.Apoptosis resistance towards TRAIL could be considerably reduced by adding the chemotherapeutic drugs 5-fluorouracil and doxorubicin as well as the kinase inhibitors LY294002[inhibition of phosphoinositol- 3-kinase(PI3K)],AG1478(epidermal growth factor receptor kinase),PD98059(MEK1),rapamycin(mam- malian target of rapamycin)and the multi-kinase inhibitor Sorafenib.Furthermore,the antiapoptotic BCL-2 proteins MCL-1 and BCL-xL play a major role in TRAIL resistance:knock-down by RNA interference increased TRAIL-induced apoptosis of HCC cells.Additionally, knock-down of MCL-1 and BCL-xL led to a significant sensitization of HCC cells towards inhibition of both c-Jun N-terminal kinase and PI3K.CONCLUSION:Our data identify the blockage of survival kinases,combination with chemotherapeutic drugs and targeting of antiapoptotic BCL-2 proteins as promising ways to overcome TRAIL resistance in HCC.

Effect of lead on ERK activity and the protective function of bFGF in rat primary culture astroglia

Objective： To observe the effects of lead on levels ofphosphorylated extracellular signal regulated kinase （p-ERK） in the cytoplasm of primary cultures of rat astroglial cells and the possible protective effect of basic fibroblast growth factor （bFGF） on lead-induced effects. Methods： The primary astroglia cells from 1-6 d old Wistar rats were cultured. The cells pretreated with the MEK1 （mitogen-activated protein kinase kinase 1） inhibitor PD98059 and bFGF, respectively, were exposed to Pb acetate of different concentrations for different times. Western blotting and reverse transcription polymerase chain reaction （RT-PCR） methods were used to detect the protein and mRNA expressions of ERK. Results： mRNA expression for ERK peaked 15 min after initiation of lead exposure （P〈0.05） and protein expression of p-ERK peaked at 30 min （P〈0.05）. ERK mRNA levels and p-ERK protein levels returned to baseline after 60 and 120 min of lead exposure, respectively （P〉0.05）. The increase in p-ERK levels in lead-treated cells could be inhibited by PD098059. Activation of ERK in the cells by lead was prevented by pretreatment with bFGF. Total ERK protein levels did not change under the same experimental conditions （P〉0.05）. Conclusion： Low-level lead exposure resulted in transient activation of ERK through the MEK pathway, which then returned to basal levels in the continued presence of lead. Exogenous bFGF protected ERK signaling components in astroglia from lead poisoning.

Sorafenib inhibits growth and metastasis of hepatocellular carcinoma by blocking STAT3

AIM: To investigate the inhibitory role and the underlying mechanisms of sorafenib on signal transducer and activator of transcription 3 (STAT3) activity in hepatocellular carcinoma (HCC).METHODS: Human and rat HCC cell lines were treated with sorafenib. Proliferation and STAT3 dephosphorylation were assessed. Potential molecular mechanisms of STAT3 pathway inhibition by sorafenib were evaluated. In vivo antitumor action and STAT3 inhibition were investigated in an immunocompetent orthotopic rat HCC model.RESULTS: Sorafenib decreased STAT3 phosphorylationat the tyrosine and serine residues (Y705 and S727), but did not affect Janus kinase 2 (JAK2) and phosphatase shatterproof 2 (SHP2), which is associated with growth inhibition in HCC cells. Dephosphorylation of S727 was associated with attenuated extracellular signal-regulated kinase (ERK) phosphorylation, similar to the effects of a mitogen-activated protein kinase (MEK) inhibitor U0126, suggesting that sorafenib induced S727 dephosphorylation by inhibiting MEK/ERK signaling. Meanwhile, sorafenib could also inhibit Akt phosphorylation, and both the phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002 and Akt knockdown resulted in Y705 dephosphorylation, indicating that Y705 dephosphorylation by sorafenib was mediated by inhibiting the PI3K/Akt pathway. Finally, in the rat HCC model, sorafenib signifi cantly inhibited STAT3 activity, reducing tumor growth and metastasis.CONCLUSION: Sorafenib inhibits growth and metastasis of HCC in part by blocking the MEK/ERK/STAT3 and PI3K/Akt/STAT3 signaling pathways, but independent of JAK2 and SHP2 activation.

N2L,a novel lipoic acid-niacin dimer,attenu⁃ates ferroptosis and decreases lipid peroxida⁃tion in HT22 cells

OBJECTIVE N2L is a novel lipoic acid-niacin dimer regulating lipid metabolism with multifunction,including antioxidant effect.We investigated the protective effect of N2L and the underlying mechanisms under the ferroptosis inducer RAS-selective lethality 3(RSL3)treat⁃ment in HT22 cells.METHODS HT22 cells were pretreated with N2L and then were treated with RSL3 to establish a ferroptosis cell model.MTT assay was used to detect the cell survival rate.Free radical probe(dihydroethidium,DHE)and ferrous probe FerroOrange were used to detect the contents of free radicals and ferrous ions in cells.The ultrastructure of mitochondria of treat⁃ed cells was observed by transmission electron microscope.The expression of ferroptosis-relat⁃ed proteins acyl-CoA synthetase long-chain family member 4(ACSL4),glutathione peroxidase 4(GPX4),cyclooxygenase-2(COX-2),ferritin Heavy Chain 1(FTH1),nuclear factor E2-related factor 2/heme oxygenase-1,and phosphoryla⁃tion levels of the c-Jun N-terminal kinase(JNK)/extracellular regulated protein kinases(ERK)pathway were detected by Western blotting.RE⁃SULTS RSL3 decreased the cell viability and induced excessive accumulation of(reactive oxy⁃gen species)ROS in HT22 cells.N2L pretreat⁃ment effectively protected HT22 cells against lipid peroxidation.What′s more,N2L recovered GPX4 protein expression and blocked the increase of COX-2 and ACSL4 expressions.Moreover,N2L also significantly prevented FTH1 from downregulation and maintained iron homeo⁃stasis.Finally,N2L pretreatment could decrease JNK/ERK activation induced by RSL3.CON⁃CLUSION N2L is an excellent ferroptosis inhibi⁃tor,and its anti-ferroptosis mechanism may be related to the reduction of lipid peroxidation and the regulation of iron homeostasis.

6-OHDA Induces Cycle Reentry and Apoptosis of PC12 Cells through Activation of ERK1/2 Signaling Pathway

This study investigated the effect and mechanism of cell cycle reentry induced by 6-hydrodopamine （6-OHDA） in PC12 cells. By using neural differentiated PC12 cells treated with 6-OHDA, the apoptosis model of dopaminergic neurons was established. Cell viability was measured by MTT. Cell apoptosis and the distribution of cell cycle were assessed by flow cytometry. Western blot was used to detect the activation of extracellular regulator kinasel/2 （ERK1/2） pathway and the phosphorylation of retinoblastoma protein （RB）. Our results showed that after PC12 cells were treated wtih 6-OHDA, the viability of PC12 cells was declined in a concentration-dependent manner. Flow cytornetry revealed that 6-OHDA could increase the apoptosis ratio of PC12 cells in a time-dependent manner. The percentage of ceils in G0/G1 phase of cell cycle was decreased and that in S phase and G2/M phase increased. Simultaneously, ERK1/2 pathway was activated and phosphorylated RB increased. It was concluded that 6-OHDA could induce cell cycle reentry of dopaminergic neurons through the activation of ERK1/2 pathway and RB phosphorylation. The aberrant cell cycle reentry contributes to the apoptosis of dopaminergic neurons.

SIGNAL MECHANISM OF INHIBITION OF BIFIDOBACTERIA ON GROWTH OF COLON CANCER

Objective: To explore the antitumor mechanisms of bifidobacteria adolescence in vivo. Methods: The content of extracellular signal regulated proteins (ERK)1/2, C-Jun N-terminal kinase (JNK), p38, c-fos and c-jun in nude mouse transplanted large bowel carcinoma was detected by using laser confocal microscopy. The expression of NF-κB was determined by immunohistochemistry. Results: After the nude mouse transplanted tumor was treated with bifidobacteria, the average fluorescent strength of ERK1/2, JNK, c-fos and c-jun was significantly lower than that in tumor control group (P<0.01). The average fluorescent strength of p38 was not obvious difference in the two groups (P>0.05). The positive cell density of NF-κB in large bowel carcinoma transplantation tumors in Bifidobacterium injection group was markedly lower than that in tumor group(P<0.01). Conclusion: bifidobacteria adolescence could markedly decrease the activity of ERK1/2 and JNK, the expression c-fos and c-jun, and the activity of NF-κB.

Effect of Artemisia decoction on liver function and pERK/eIF2a signaling pathway in rats with alcoholic liver fibrosis

Objective: To investigate the effects of Artemisia decoction on liver function and phosphorylation of extracellular regulated protein kinase/eukaryotic translation initiation factor 2α (pERK/eIF2a) signaling pathway in rats with alcoholic liver fibrosis. Methods: A total of 40 healthy Sprague-Dole (SD) rats were randomly divided into 4 groups: the normal group, the sham operation group, the model group and the Artemisia decoction group, with 10 rats in each group. Alcoholic liver fibrosis model was established by "alcohol-corn oil-pyrazole" combined with a 12-week high-fat diet. After successful modeling, the normal group was not treated, and the sham operation group was given saline. The model group and the Artemisia decoction group were given the same amount of wormwood soup at the same time. The serum hydroxyproline (HYP), hyaluronidase (HA), laminin (LN), type IV collagen (CIV), type III procollagen (PIIINP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), γ-glutamyltranspeptidase (γ-TG), total bile acid (TBA), total bilirubin (TB), albumin (ALB), total cholesterol (CHOL), triglyceride (TG), glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) levels were measured after 12 weeks of continuous treatment. The degree of liver fibrosis was observed by hematoxylin-eosin staining (HE). The expression of pERK/eIF2a signaling pathway in liver tissue was detected by enzyme-linked immunosorbent assay (ELISA). Results: Compared with the normal group, the levels of serum HYP, HA, LN, CIV, PIIINP, AST, ALT, γ-GT, ALP, TBL and TB in the sham operation group were not significantly changed (P>0.05), while these indexes in the model group were significantly elevated (P<0.01). After treatment with Artemisia decoction, the levels of serum HYP, HA, LN, CIV, PIIINP, AST, ALT, γ-GT, ALP, TBL and TB were significantly lower than those in the model group (P<0.01). The serum albumin, lipid metabolism and oxidative damage indicators showed that there was no significant change in serum ALB, CHOL, TG, GSH, SOD and MDA levels in the sham operation group compared with the normal group (P>0.01). The levels of GSH and SOD in the model group were significantly decreased (P<0.01), and the levels of CHOL, TG and MDA in the model group were significantly increased (P<0.01). Compared with the model group, the serum ALB, GSH and SOD levels were significantly increased (P<0.01), and CHOL, TG and MDA levels were significantly decreased after giving intervention with Artemisia decoction (P<0.01). The results of HE staining showed that compared with the control group, the morphology of the liver sections of the sham operation group was normal, while the liver sections of the model group showed obvious vacuolization changes. The liver sections of the rats treated with Artemisia decoction were significantly improved. The results of ELISA showed that there was no significant change in the levels of pERK and eIF2a in the liver tissue of the sham operation group compared with the normal group (P>0.05). The levels of pERK and eIF2a in the liver tissue of the model group were significantly increased (P<0.01). After treatment with Artemisia decoction, the levels of pERK and eIF2a in rat liver tissues were significantly lower than those in the model group (P<0.01). Conclusion: Artemisia decoction can effectively block the degree of liver fibrosis in rats with alcoholic liver fibrosis, reduce liver fibrosis index and improve hepatobiliary function. This effect may be related to inhibition of the pERK/eIF2a signaling pathway.

Activation of glycine site and GluN2B subunit of NMDA receptors is necessary for ERK/CREB signaling cascade in rostral anterior cingulate cortex in rats:Implications for affective pain

Objective The rostral anterior cingulate cortex （rACC） is implicated in processing the emotional component of pain. N-methyl-D-aspartate receptors （NMDARs） are highly expressed in the rACC and mediate painrelated affect by activating a signaling pathway that involves cyclic adenosine monophosphate （cAMP）/protein ki- nase A （PKA） and/or extracellular regulated kinase （ERK）/cAMP-response element-binding protein （CREB）. The present study investigated the contributions of the NMDAR glycine site and GluN2B subunit to the activation of ERK and CREB both in vitro and in vivo in rat rACC. Methods Immunohistochemistry and Western blot analy- sis were used to separately assess the expression of phospho-ERK （pERK） and phospho-CREB （pCREB） in vitro and in vivo. Double immunostaining was also used to determine the colocalization of pERK and pCREB. Results Both bath application of NMDA in brain slices in vitro and intraplantar injection of formalin into the rat hindpaw in vivo induced significant up-regulation of pERK and pCREB in the rACC, which was inhibited by the NMDAR antago- nist DL-2-amino-5-phospho-novaleric acid. Selective blockade of the NMDAR GluN2B subunit and the glycine- binding site, or degradation of endogenous D-serine, a co-agonist for the glycine site, significantly decreased the up- regulation of pERK and pCREB expression in the rACC. Further, the activated ERK predominantly colocalized with CREB. Conclusion Either the glycine site or the GluN2B subunit of NMDARs participates in the phosphorylation of ERK and CREB induced by bath application of NMDA in brain slices or hindpaw injection of 5% formalin in rats, and these might be fundamental molecular mechanisms underlying pain affect.

1,5-dicaffeoylquinic acid protects primary neurons from amyloid β1-42-induced apoptosis via PI3K/Akt signaling pathway

Background Recently, 1,5-dicaffeoylquinic acid （1,5-DQA）, a caffeoylquinic acid derivative isolated from Aster scaber, was found to have neuroprotective effects. However, the protective mechanisms of 1,5-DQA have not yet been clearly identified. The purpose of this study was to explore the protective mechanisms of 1,5-DQA on neuronal culture. Methods We investigated the neuroprotective effects of 1,5-DQA against amyloid IB1-42 （Aβ42）-induced neurotoxicity in primary neuronal culture. To evaluate the neuroprotective effects of 1,5-DQA, primary cultured cortical neurons from neonate rats were pretreated with 1,5-DQA for 2 hours and then treated with 40 pmol/L Aβ42 for 6 hours. Cell counting kit-8, Hoechst staining and Western blotting were used for detecting the protective mechanism. Comparisons between two groups were evaluated by independent t test, and multiple comparisons were analyzed by one-way analysis of variance （ANOVA）. Results 1,5-DQA treated neurons showed increased neuronal cell viability against Aβ42 toxicity in a concentration- dependent manner, both phosphoinositide 3-kinase （PI3K）/Akt and extracellular regulated protein kinase 1/2 （Erkl/2） were activated by 1,5-DQA with stimulating their upstream tyrosine kinase A （Trk A）. However, the neuroprotective effects of 1,5-DQA were blocked by LY294002, a PI3K inhibitor, but not by PD98059, an inhibitor of mitogen-activated protein kinase kinase. Furthermore, 1,5-DQA＇s anti-apoptotic potential was related to the enhanced inactivating phosphorylation of glycogen synthase kinase 313 （GSK3β） and the modulation of expression of apoptosis-related protein Bcl-2/Bax. Conclusion These resutts suggest that 1,5-DQA prevents AI342-induced neurotoxicity through the activation of PI3K/Akt followed by the stimulation of Trk A, then the inhibition of GSK313 as well as the modulation of Bcl-2/Bax.

Hepatitis B virus X protein upregulates tumor necrosis factor-α expression of rat mesangial cell line via ERKs pathway

Hepatitis B virus X protein(HBx),a 17-kd protein encoded by X gene of hepatitis B virus(HBV),has been shown to function as a transcriptional trans-activator of a variety of viral and cellular promoter/enhancer elements.The aim of the study is to investigate the extracellular regulated protein kinases(ERKs)pathway of HBx on glomerular mesangial cell(GMC)proliferation and tumor necrosis factor-α(TNF-α)expression.The HBV X gene was amplified by polymerase chain reaction(PCR),inserted into the eukaryotic expression vector pCI-neo and confirmed by restriction endonuclease digestion and sequence analysis.PCI-neo containing HBV X gene(pCI-neo-X)was then transfected into cultured GMC line via liposome.GMC proliferation,TNF-αand its mRNA expression were compared in the condition of with or without U0126 in culture media.HBx,ERK1/2 and p-ERK1/2 expression in GMCs was assessed by Western blotting.TNF-αmRNA expression was assessed by semi-quantitative reverse transcription-PCR(RT-PCR).TNF-αlevel in supernatants was measured by ELISA.GMC proliferation was detected by 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide(MTT)kit.The results showed that HBx expression was found in transfected GMCs and became prominent at 36th and 48th h after transfection whether with or without U0126 in culture media.TNF-αmRNA expression was significantly decreased in U0126 group compared with U0126-free group.TNF-αlevels in supernatants in PCI-neo-X transfection without U0126 group were(189.0�18.1)and(172.3�24.3)pg/mL at 36th and 48th h after transfec-tion,respectively.In contrast,TNF-αlevels in supernatants with U0126 were(65.6�11.6)and(84.0�24.6)pg/mL at 36th and 48th h,respectively.The TNF-αlevels in the latter groups were significantly lower than those in the former groups(P<0.05).GMCs proliferation was also lower in added U0126 group at 36th and 48th h after transfection.From above,we can conclude that HBx could induce GMC proliferation and increase TNF-αmRNA expression and its protein production.HBx upregulates TNF-αexpression and induces cell proliferation of GMC line partly through ERK1/2 signal transduction pathway.

The regulatory effect of ERK1/2 signal pathway on production of TNFα induced by LPS in mice Kupffer cells

Objective: To study the rule of ERK1/2 activity and regulative effect of ERK1/2 pathway on the production of pro inflammatory cytokine TNFα in mice Kupffer cells (mKC) induced by LPS, and to exploring novel methods to prevent and treat clinical patients of endotoxemia. Methods: Immunoprecipitate kinase assay and Western blotting analysis were used to detect the phosphorylated ERK1/2 kinase activity in mKC stimulated by LPS, and ELISA was used to study the effect of ERK1/2 signaling cascade on LPS induced TNFα production in mKC. Results: In mKC, LPS treatment resulted in transient and rapid increase of kinase activity of ERK1/2 that phosphorylated their specific substrate ELK 1, with maximal value at 30 minutes and a return near to baseline within 2 hours, and LPS induced ERK1/2 activity from LPS concentration of 10 pg/ml to the top activity at 100 ng/ml . No activity was observed in unstimulated mKC. Inhibition of the ERK1/2 pathway using the specific ERK 1/2 signal pathway inhibitor PD98059 caused a marked and concentration dependent reduction of TNFα production. Conclusions: The results show that LPS can markedly activate ERK1/2 pathway in mKC. PD98059 causes a significant and concentration dependent reduction of TNFα production. ERK1/2 may be a novel target to treat clinical patient of endotoxemia.