Apolipoprotein E enhances migration of endometrial cancer cells byactivating the ERK/MMP9 signaling pathway / 南方医科大学学报

OBJECTIVE@#To study the role of apolipoprotein E (APOE) in regulating endometrial cancer metastasis and explore the signaling pathway in the regulatory mechanism.@*METHODS@#Human endometrial cancer cell line HEC-1B was transfected with a control siRNA (siCtrl) or a specific siRNA targeting APOE (siAPOE) or with either pEGFP-N1 plasmid or an APOEoverexpressing plasmid. The changes in migration, proliferation, apoptosis and cell cycle of the transfected cells were examined using wound healing assay, Transwell migration assay, MTT assay, flow cytometry, and Hoechst staining. The activity of the ERK/MMP9 signaling pathway in the transfected cells was assessed using RT-qPCR and Western blotting. The expression level of APOE in clinical specimens of endometrial cancer tissues were detected using immunohistochemistry and its correlation with differentiation of endometrial cancer tissues was analyzed.@*RESULTS@#Wound healing assay and Transwell migration assay showed that compared with those in siCtrl group, HEC-1B cells transfected with siAPOE showed significantly reduced migration ability (P < 0.05), whereas APOE overexpression significantly promoted the migration of the cells (P < 0.05). Neither APOE knockdown nor overexpression produced significant effects on HEC-1B cell proliferation as shown by MTT assay and flow cytometry. Hoechst staining revealed that transfection with siAPOE did not significantly affect apoptosis of HEC-1B cells. APOE knockdown obviously reduced and APOE overexpression enhanced ERK phosphorylation and MMP9 expression in HEC-1B cells (P < 0.05). Treatment with U0126 partially reversed the effects of APOE overexpression on ERK phosphorylation, migration and MMP9 expression in HEC-1B cells (P < 0.05). APOE is highly expressed in clinical samples of endometrial cancer tissues as compared with the adjacent tissues.@*CONCLUSION@#APOE is highly expressed in endometrial cancer tissues to promote cancer cell migration by enhancing ERK phosphorylation and MMP9 expression.

Inhibition of activated K-opioid receptor to myocardical hypertrophy induced by ET-1 in neonatal rats by extracellular signal-regulated kinase pathway / 中国药理学通报

Aim To investigate the inhibitory effect of kappa-opioid receptor(κ-OR)stimulation on extracellular signal-regulated kinase pathway on ET-1-induced cardiomyocyte hypertrophy in vitro cultured myocardial cells from neonatal rats.Methods Myocardial cells of neonatal rats were cultured in vitro.The hypertrophic myocytes were induced by ET-1(10 nmol·L-1)before κ-OR agonist U50488H(1 μmol·L-1)was administered.The antihypertrophic effect of κ-OR stimulation was observed in the presence of U0126(1μmol·L-1), Ro-31-8220(50 nmol·L-1)and PTX(5 mg·L-1).The cardiomyocytes volume was measured by computer photographalysis system.The relative expression of ERK1/2 was determined by Western blot.The morphological changes in cardiomyocytes were observed under an inverted phase contrast microscope.The expression of mRNA of atrial natriuretic peptide(ANP)was determined by RT-PCR.Results Compared with normal control group, ET-1 could induced cardiomyocyte hypertrophy.Compared with ET-1 model group, U50488H(1 μmol·L-1)could obviously inhibit ET-1-induced increase of the cardiomyocytes volume, expression of ANPmRNA and expression of ERK1/2, which was similar to U0126(1 μmol·L-1)and Ro-31-8220(50 nmol·L-1); however, the inhibitory effects of U50488H were partly lost when preincubated with U0126(1 μmol·L-1)and Ro-31-8220(50 nmol·L-1); the inhibitory effects of U50488H, U0126(1 μmol·L-1)and Ro-31-8220(50 nmol·L-1)were lost when preincubated with NOR-BNI.Conclusion The stimulation of kappa-opiod can inhibit myocardial hypertrophy induced by ET-1, which is possibly via attenuating ERK1/2.

Effects of budesonide on proliferation and apoptosis of airway smooth muscle cells in asthmatic rats / 解剖学报

Objective To investigate the effect of budesonide ( BUD) inhalation on the proliferation and apoptosis of airway smooth muscle cells ( ASMCs) in asthmatic rats and its molecular biological mechanism. Methods Totally 40 SD rats were randomly divided into control group, asthma model group, low (0. 25 mg/kg) and high (2 mg/kg) BUD group. The rat asthma model was induced by ovalbumin (VOA) combined with aluminium hydroxide Gel sensitization stimulation. After sensitization, the intervention group inhaled different doses of BUD before stimulation. The related parameters of lung tissue and airway were measured and calculated by medical image analysis system, immunofluorescence was used to detect the expression of type I collagen ( Col I ) and Col III in rat airway smooth muscle ( ASM ), and the protein expressions of Bcl-2, Bax, Caspase-3, phosphorylated ERK 1 and 2(p-ERK 1 / 2), p-p38 MAPK were detected by Western blotting. The proliferation activity of ASMCs was detected by MTT method, and the apoptosis rate of ASMCs was detected by flow cytometry. Results Compared with the control group, airway remodeling occurred in the asthmatic model group, and the airway wall thickness ( WAt/Pbm ), inner wall thickness ( WAi/Pbm ) and smooth muscle thickness ( WAm/Pbm ) increased, compared with the model group, the airway remodeling was inhibited in BUD intervention group, and the tracheal WAt/Pbm, WAi/Pbm and WAm/Pbm decreased in bud treatment group. BUD could decrease the proliferation activity of ASMCs, increase the apoptosis rate of ASMCs, inhibit the expression of Col I and Col III, deregulate the expression of Bcl-2, upregulate the expression of Bax and Caspase-3 ( all P<0. 05), and inhibit the activity of ERK 1/2 and p38 MAPK signal pathway. Conclusion BUD can inhibit the proliferation and the promote apoptosis of ASMCs in asthmatic rats, which may be related to the inhibition of ERK 1/2 and p38 MAPK signal pathways.

Analgesic effect of gabapentin combined with agmatine on neuropathic pain in diabetic rats / 国际药学研究杂志

Objective: To investigate analgesic effect of gabapentin(GBP)combined with agmatine(AGM)on diabetic neuropathic pain(DNP)model rats and explore possible mechanism. Methods: SPF SD male rats were injected intraperitoneally with STZ 65 mg/kg to create a neuropathic pain model of diabetic rats. The model rats were randomly divided into 5 groups(n=8): the model group, low-dose GBP group(30 mg/kg, ip), high-dose GBP group(100 mg/kg, ip), AGM group(80 mg/kg, ig)and the GBP-AGM combined group(GBP 30 mg/kg, ip+AGM 80 mg/kg, ig). In addition, a control group was set with 8 randomly selected normal rats. The control group and the model group were intragastrically and intraperitoneally administered an equal volume of physiological saline, respectively, while the test groups were administered drugs with the given dose in the indicated manner, all for continuous 14 days. The rat body mass, tail vein blood glucose, mechanical withdrawal threshold(MWT)and thermal withdrawal latency(TWL) were measured on day 1 before STZ injection and every 7th day after STZ injection, and the plantar tenderness meter was used for the MWT and TWL measurement. The rats were sacrificed 24 h after the last administration, and the spinal cord tissues were harvested. Western blotting was used to detect the expression of p-ERK and c-Fos protein in spinal cord tissues. Results: Compared with the normal control group, the body mass was reduced, blood glucose increased, MWT decreased, and TWL shortened in the model group, all significantly(P0.05)in all of the drug-test groups, while the MWT was increased and the TWL was prolonged in the GBP 100 mg/kg group and the GBP-AGM combined group(both P<0.01). Western blotting results showed that the level of p-ERK and c-Fos protein in the spindal cord was significantly higher in the model group than in the control group(P<0.05). Further, the p-ERK and c-Fos protein level was significantly lower in the GBP+AGM combined group than in the model group(P<0.05)and there was no statistical difference between the GBP 100 mg/kg group and the GBP-AGM combination group. Conclusion: The combination of GBP 30 mg/kg with AGM 80 mg/kg could alleviate neuropathic pain in diabetic rats, which is similar to GBP 100mg/kg and the analgesic effect is likely related to the inhibition of ERK/c-Fos signaling pathway in the spina cord.

Advances in Study on Relationship Between Epithelial Sodium Channel and Inflammatory Bowel Disease / 胃肠病学

Inflammatory bowel disease (IBD)is an autoimmune disease leading to diarrhea,abdominal pain,and weight loss. The pathogenesis of diarrhea remains unclear,however,increasing evidence has shown that the epithelial sodium channel (ENaC)is associated with diarrhea. ENaC is crucial in the control of sodium homeostasis,extracellular fluid volume,blood pressure. This article reviewed advances in study on relationship between ENaC and IBD.

Preventive Effect of Caffeine on Alzheimer's Disease / 现代生物医学进展

Objective:To explore the effects of caffeine on the prevention of Alzheimer's disease (AD).Methods:Use Ethanol as a solvent to extract the caffeine in tea and then injecting 5％ D-galactose saline solution 1ml/d/kg to establish aging model mice.Divide mice randomly into experimental group (high-dose/low-dosecaffeine),positive control group,negative control group,and normal con-trol group (NS) and injecting appropriate drugs for consecutive four weeks.Test superoxyde dismutase (SOD) and malondialdehvde (MDA) periodically.Take mice's hippocampus and use Western blotting to detect the expression of brain derived neurotrophic factor (BDNF) and extracellular signal-regulated kinasesl/2 (p-ERK1/2).Results:The expression of BDNF and p-ERK1/2,negative control group is less than low-dose experimental group and positive control group (P＜0.01);The p-ERK1/2 expression of injecting D-galactose mice was significantly lower than normal group,negative control group compared weth the normal group,the differencd was significant (P＜0.05).The level of SOD in model group was significantly lower than that in normal control group,high,low dose caffeine group and positive control group (P＜0.01),but the level of MDA is opposite.Conclusions:Caffeine can delay aging process by increasing the level of SOD in aging mice,and enhancing the expression of BDNF and P-ERK1/2.Caffeine does a lot to prevent AD.

Sustained Intracellular Acidosis Triggers the Na⁺/H⁺ Exchager-1 Activation in Glutamate Excitotoxicity

The Na⁺/H⁺ exchanger-1 (NHE-1) is a ubiquitously expressed pH-regulatory membrane protein that functions in the brain, heart, and other organs. It is increased by intracellular acidosis through the interaction of intracellular H⁺ with an allosteric modifier site in the transport domain. In the previous study, we reported that glutamate-induced NHE-1 phosphorylation mediated by activation of protein kinase C-β (PKC-β) in cultured neuron cells via extracellular signal-regulated kinases (ERK)/p90 ribosomal s6 kinases (p90RSK) pathway results in NHE-1 activation. However, whether glutamate stimulates NHE-1 activity solely by the allosteric mechanism remains elusive. Cultured primary cortical neuronal cells were subjected to intracellular acidosis by exposure to 100 μM glutamate or 20 mM NH₄Cl. After the desired duration of intracellular acidosis, the phosphorylation and activation of PKC-β, ERK1/2 and p90RSK were determined by Western blotting. We investigated whether the duration of intracellular acidosis is controlled by glutamate exposure time. The NHE-1 activation increased while intracellular acidosis sustained for >3 min. To determine if sustained intracellular acidosis induced NHE-1 phosphorylation, we examined phosphorylation of NHE-1 induced by intracellular acidosis by transient exposure to NH₄Cl. Sustained intracellular acidosis led to activation and phosphorylation of NHE-1. In addition, sustained intracellular acidosis also activated the PKC-β, ERK1/2, and p90RSK in neuronal cells. We conclude that glutamate stimulates NHE-1 activity through sustained intracellular acidosis, which mediates NHE-1 phosphorylation regulated by PKC-β/ERK1/2/p90RSK pathway in neuronal cells.

Platelet Rich Plasma (PRP) Produces an Atherofibrotic Histophenotype During Craniofacial Bone Repair Due to Changes of Immunohistochemical Expression of Erk1/2, p38α /β, Adiponectin and Elevated Presence of Cells Exhibiting B-scavenger Receptor (CD36+)

Abstract The platelet-extracellular matrix interaction in platelet rich plasma (PRP) through thrombospondin receptor-CD36 induces the secretion of growth factors responsible for cellular proliferation and differentiation during the repair process. Since CD36 also acts as a class B-scavenger-receptor for development of foam-like cells and mitogen-activated kinases, such as Erk1/2 and p38α/β, are important proteins activated by platelet growth factor, the aim of this study was to evaluate the immunohistochemical presence of CD36, Erk1/2, p38α/β during the bone repair treated and non-treated with PRP and to compare these results with the histomorphometry of repair. Simultaneously, the immunopresence of adiponectin was analyzed, which may contribute to osteogenesis at the same time it inhibits fibrosis and impairs adipogenesis and foam cell formation in the medullary area. An artificial bone defect measuring 5×1 mm was produced in the calvaria of 56 Wistar rats. The defects were randomly treated with autograft, autograft+PRP, PRP alone and sham. The animals were euthanized at 2 and 6 weeks post-surgery. Data were analyzed by ANOVA followed by non-parametric test Student Newman-Keuls (p<0.05) for histomorphometric and immunohistochemical interpretation. The results revealed that in specimens that received PRP the immunopositivity for Erk1/2, p38α/β and CD36 proteins increased significantly while the immunohistochemical expression of adiponectin decreased simultaneously. There was also an accentuated reduction of bone matrix deposition and increase of the medullary area represented by fibrosis and/or presence of foam-like cells, which exhibited immunophenotype CD36+adiponectin. The findings of this study suggest that PRP acted as an inhibitor of osteogenesis during the craniofacial bone repair and induced a pathological condition that mimics an atherofibrotic condition.

Resumo A interação da matriz extracelular-plaquetas no plasma rico em plaquetas (PRP) através de receptor trombospondina CD36 induz a secreção de fatores de crescimento responsáveis pela proliferação e diferenciação celular durante o processo de reparo. Uma vez que o CD36 também age como receptor scavenger de classe B para o desenvolvimento de células do tipo espuma, e as quinases ativadas por mitógenos, tais como ERK1/2 e p38α/β, são importantes proteínas ativadas por fator de crescimento das plaquetas, o objetivo deste estudo foi avaliar a presença imunoistoquímica de CD36, ERK1/2, p38α/β durante o reparo ósseo tratado e não-tratado com PRP e comparar estes resultados com a histomorfometria do reparo. Simultaneamente, analisou-se a imunopresença da adiponectina, que pode contribuir para osteogênese ao mesmo tempo que inibe a fibrose e prejudica a formação de células tipo espuma/xantomatosas na área medular. Um defeito artificial de osso medindo 5×1 mm foi produzido na calvária de 56 ratos Wistar. Os defeitos foram tratados aleatoriamente com auto-enxerto, enxerto autógeno+PRP, PRP apenas e sham. Os animais foram sacrificados 2 e 6 semanas pós-cirurgia. Os dados foram examinados por meio de ANOVA, seguido pelo teste não-paramétrico Student Newman-Keuls (p<0,05) para a interpretação histomorfométrica e imunoistoquímica. Os resultados revelaram que as amostras que receberam PRP aumentaram significativamente a imunopositividade para as proteínas ERK1/2, p38α/β e CD36, simultaneamente à diminuição de expressão imunoistoquímica da adiponectina. Houve também expressiva redução de deposição de matriz óssea e aumento da área medular representada por fibrose e/ou presença de células do tipo espuma que apresentaram imunofenótipo CD36 + adiponectina. Estes resultados sugerem que o PRP atuou como um inibidor da osteogênese durante o reparo ósseo craniofacial e induziu uma condição patológica que mimetiza uma condição aterofibrótica.

Mechanisms of ERK1/2 signaling pathway participate in inflammatory reaction caused by coronary heart disease / 天津医药

Objective To investigate the effects of ERK1/2 signaling pathway on coronary atherosclerosis-associated inflammatory reaction in autopsy cases. Methods Forty-five autopsy cases were divided into three groups:coronary arterydisease (CHD)-associated death group, CHD group and control group (n=15 for each group). The inflammatory cell infiltration in myocardial tissues was observed through staining leucocyte common antigen (CD45) by HE and immunohistochemistry method. The protein expression level and distribution in extracellular signal-regulated kinase 1/2 (t-ERK1/2) and phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2) of myocardial tissues were detected by immunohistochemistry and Western-blot assay. The expression level of tumor necrosis factor α (TNF-α) was determined using semiquantitative RT-PCR analysis. The activity of nuclear factor (NF)-κB was assessed using electrophoretic mobility shift assay (EMSA). Results Compared with CHD and control groups, myocardial inflammatory cell counts, phosphorylation of ERK1/2, TNF-α mRNA expression and NF-κB activation were significantly increased in CHD-associated death group (P < 0.05). Western blot analysis showed that the phosphorylation of ERK1/2 was positively correlated with expression of TNF-αmRNA and the number of inflammatory cells in CHD-associated death group (r=0.675, P<0.01;r=0.893, P<0.01). Conclusion Results reveal that the activation of ERK1/2 signaling pathway is considered as an important mechanism for coronary atherosclerosis caused myocardial inflammatory reaction, which indicates that the inhibition of ERK1/2 signal transduction pathway may become a potential new target for prevention and treatment of atherosclerotic coronary infarction.

Effects of moxibustion pretreatment on extracellular signal-regulated kinase signaling transduction pathway in the gastric tissues of rats with gastric mucosal damage / 针灸推拿医学（英文版）

Objective: To observe the effects of moxibustion pretreatment on the protein expressions of epidermal growth factor receptor (EGFR), phosphorylation extracellular signal-regulated kinase 1/2 (p-ERK1/2) and activated protein-1 (AP-1), the key factors of extracellular signal-regulated kinase signaling transduction pathway in gastric tissue of rats with stress-induced gastric mucosal damage, and to discuss the mechanisms of moxibustion therapy in promoting the restoration of damaged gastric mucosa. Methods: Thirty Sprague-Dawley (SD) rats were randomly divided into a normal group, a model group, and a moxibustion group using the random digits table, 10 in each group. Except the rats in the normal group, rats in the other two groups were used to make stress-induced gastric mucosal damage model using restraint and cold stress. Before modeling, rats in the moxibustion group were alternately treated with moxibustion at Zusanli (ST 36) and Zhongwan (CV 12), or Pishu (BL 20) and Weishu (BL 21), once a day, for a total of 8 d. Histological changes of gastric mucosa were observed under the light microscopy, the expression of gastric tissue p-ERK1/2 was detected by immunohistochemistry assay, and the protein levels of EGFR and AP-1 were measured by Western blots. Results: Compared with rats in the normal group, gastric mucosal damage was more serious, and protein expressions of gastric tissue EGFR, p-ERK1/2 and AP-1 increased in the model group (P Conclusion:Moxibustion at Zusanli (ST 36), Zhongwan (CV 12), Pishu (BL 20) and Weishu (BL 21) couldincrease EGFR, p-ERK1/2 and AP-1 expression levels in gastric tissue of stress-induced gastric mucosal damage rats, maintain the information transfer function of ERK signaling transduction pathway, and promote restoration of gastric mucosal damage.

Protective Effect of an Isoflavone, Tectorigenin, Against Oxidative Stress-induced Cell Death via Catalase Activation

BACKGROUND: Isoflavones are biologically active compounds that occur naturally in a variety of plants, with relatively high levels in soybean. Tectorigenin, an isoflavone, protects against hydrogen peroxide (H2O2)-induced cell damage. However, the underlying mechanism is unknown. METHODS: The MTT assay was performed to determine cell viability. Catalase activity was assessed by determining the amount of enzyme required to degrade 1 μM H2O2. Protein expression of catalase, phospho-extracellular signal-regulated kinase (ERK), IκB-α, and NF-κB were evaluated by Western blot analysis. A mobility shift assay was performed to assess the DNA-binding ability of NF-κB. Transient transfection and a NF-κB luciferase assay were performed to assess transcriptional activity. RESULTS: Tectorigenin reduced H2O2-induced death of Chinese hamster lung fibroblasts (V79-4). In addition, tectorigenin increased the activity and protein expression of catalase. Blockade of catalase activity attenuated the protective effect of tectorigenin against oxidative stress. Furthermore, tectorigenin enhanced phosphorylation of ERK and nuclear expression of NF-κB, while inhibition of ERK and NF-κB attenuated the protective effect of tectorigenin against oxidative stress. CONCLUSIONS: Tectorigenin protects cells against oxidative damage by activating catalase and modulating the ERK and NF-κB signaling pathway.

STAT3 and ERK Signaling Pathways Are Implicated in the Invasion Activity by Oncostatin M through Induction of Matrix Metalloproteinases 2 and 9

PURPOSE: Our previous studies have shown that oncostatin M (OSM) promotes trophoblast invasion activity through increased enzyme activity of matrix metalloproteinase (MMP)-2 and -9. We further investigated OSM-induced intracellular signaling mechanisms associated with these events in the immortalized human trophoblast cell line HTR8/SVneo. MATERIALS AND METHODS: We investigated the effects of OSM on RNA and protein expression of MMP-2 and -9 in the first-trimester extravillous trophoblast cell line (HTR8/SVneo) via Western blot. The selective signal transducer and activator of transcription (STAT)3 inhibitor, stattic, STAT3 siRNA, and extracellular signal-regulated kinase (ERK) siRNA were used to investigate STAT3 and ERK activation by OSM. The effects of STAT3 and ERK inhibitors on OSM-induced enzymatic activities of MMP-2 and -9 and invasion activity were further determined via Western blot and gelatin zymography. RESULTS: OSM-induced MMP-2 and -9 protein expression was significantly suppressed by STAT3 inhibition with stattic and STAT3 siRNA silencing, whereas the ERK1/2 inhibitor (U0126) and ERK silencing significantly suppressed OSM-induced MMP-2 protein expression. OSM-induced MMP-2 and MMP-9 enzymatic activities were significantly decreased by stattic pretreatment. The increased invasion activity induced by OSM was significantly suppressed by STAT3 and ERK1/2 inhibition, though to a greater extent by STAT3 inhibition. CONCLUSION: Both STAT3 and ERK signaling pathways are involved in OSM-induced invasion activity of HTR8/SVneo cells. Activation of STAT3 appears to be critical for the OSM-mediated increase in invasiveness of HTR8/SVneo cells.

Promoting effect of botulinum neurotoxin serotype A heavy chain on neu-ritogenesis in cultured Neuro-2a cells / 中国病理生理杂志

AIM:To observe the neuritogenic actions of botulinum neurotoxin serotype A heavy chain ( BoNT/A HC) on cultured Neuro-2a cells and to investigate the related signaling mechanisms for the effect of BoNT /A HC. METHODS:Neuro-2a cells were treated with different doses of BoNT/A HC (0.01, 0.1, 1 and 10 nmol/L), and then the cells were harvested at 24 h, 48 h and 72 h of BoNT/A HC exposure for detecting the neurite length and the percen-tage of the cells with neuronal processes by immunofluorescence staining .The most efficient dose of BoNT/A HC was cho-sen for exposure to Neuro-2a cells as the above.Whole cell protein was harvested at different time points for detecting the protein levels of phosphorylated ERK 1/2 ( p-ERK1/2 ) and phosphorylated Akt ( p-Akt ) by Western blot .RESULTS:Low doses of BoNT/A HC stimulated the neurite outgrowth , and increased the percentage of the cells with neurites com-pared with the negative controls (P<0.05), especially in the group with 1 nmol/L of BoNT/A HC treatment.Meanwhile, the phosphorylation of ERK 1/2 and Akt was increased after treated with BoNT/A HC.There was an increasing tendency for the phosphorylation of ERK1/2 after the exposure of the cells to BoNT/A HC.The obvious increase in p-ERK1/2 was seen from 60 min to 5 h with 1 nmol/L of BoNT/A HC treatment ( P<0.05 ) , and the increased protein level of p-Akt was mainly observed at 15 min and 60 min ( P<0.05 ) .CONCLUSION: BoNT/A HC stimulates the neuritogenesis .The neuritogenic mechanism of BoNT/A HC on Neuro-2a cells might be realized by activation of the phosphorylation of ERK 1/2 and Akt.

Downregulation of Aquaporin 4 Expression through Extracellular Signal-regulated Kinases1/2 Activation in Cultured Astrocytes Following Scratch-injury / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the role of extracellular signal-regulated kinase1/2 (ERK1/2) pathway in the regulation of aquaporin 4 (AQP4) expression in cultured astrocytes after scratch-injury.</p><p><b>METHODS</b>The scratch-injury model was produced in cultured astrocytes of rat by a 10-μL plastic pipette tip. The morphological changes of astrocytes and lactate dehydrogenase (LDH) leakages were observed to assess the degree of scratch-injury. AQP4 expression was detected by immunofluorescence staining and Western blot, and phosphorylated-ERK1/2 (p-ERK1/2) expression was determined by Western blot. To explore the effect of ERK1/2 pathway on AQP4 expression in scratch-injured astrocytes, 10 µmol/L U0126 (ERK1/2 inhibitor) was incubated in the medium at 30 min before the scratch-injury in some groups.</p><p><b>RESULTS</b>Increases in LDH leakage were observed at 1, 12, and 24 h after scratch-injury, and AQP4 expression was reduced simultaneously. Decrease in AQP4 expression was associated with a significant increase in ERK1/2 activation. Furthermore, pretreatment with U0126 blocked both ERK1/2 activation and decrease in AQP4 expression induced by scratch-injury.</p><p><b>CONCLUSION</b>These results indicate that ERK1/2 pathway down-regulates AQP4 expression in scratch-injured astrocytes, and ERK1/2 pathway might be a novel therapeutic target in reversing the effects of astrocytes that contribute to traumatic brain edema.</p>

Research Development of ERK1/2 Pathway and Its Mediated Multiple Sclerosis / 世界科学技术-中医药现代化

Extracellular signal-regulated kinases 1 and 2 (ERK1/2) pathway, which was the first cell signal transduction pathway to be discovered, consisted of Ras, Raf, MEK1/2 and ERK1/2. After the activation of ERK1/2 pathway, extracellular signals can be transmitted from the cell membrane to the nucleus. It was involved in many physiological and pathological functions of cells, such as growth, proliferation, differentiation, apoptosis and etc. It was also related to the onset of many diseases, which included multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). The activation of ERK1/2 pathway can induce the activation of astrocyte, MG, T cell and macrophage, which released a variety of inflammatory cytokines. It caused myelin damage which induced MS/EAE onset. A number of studies indicated that inhibiting ERK1/2 pathway can reduce the releasing of inflammatory cytokines and myelin damage for MS/EAE alleviation. It provided an important target for the development of MS treatment medication.

MAPK immunoreactivity in streptozotocin-induced diabetic rat testis

PURPOSE: To evaluate the alterations of two mitogen-activated protein kinases (MAPK)s, extracellular signal regulated kinase (ERK) and c-Jun NH2 terminal kinase (JNK), in the testes of male rats with experimental diabetes. METHODS: Twenty males Sprague-Dawley rats were randomly divided into a control group (n=8) and a diabetes group (administration of 40 mg/kg/day streptozotocin (STZ) for five sequential days, n=12). After six weeks, testicular biopsy samples were obtained for light microscopy and immunohistochemical methods. RESULTS: The PCNA (proliferating cell nuclear antigen) index was significantly decreased in the diabetes group (p=0.004) when compared to the control group. Both total (t)-ERK and phosphor (p)-ERK immunoreactivities were significantly decreased in the diabetes group (p=0.004, p<0.001, respectively). The t-JNK immunoreactivity was unchanged in both groups (p=0.125), while p-JNK immunoreactivity was significantly increased in the diabetic group (p=0.002). CONCLUSIONS: The decrease of androgen levels in the course of diabetes may contribute to the decrease of the immunoreactivities of t-ERK and p-ERK. JNK may be activated due to the changes in various cytokines and chemochines that participate in the oxidative stress process of diabetes. Therefore, testicular apoptosis may occur and lead to infertility associated with diabetes. .

Effects of ursolic acid on NADPH oxidase subunit p47Phoxexpression and ERKL/2 pathway activation in rat hepatic stellate cells / 第二军医大学学报

Objective To investigate the effects of ursolic acid (UA) on leptin-induced NADPH oxidase (NOX) subunits p47Phox expression and ERKl/2 pathway activation of rat hepatic stellate cells (HSC-T6), and to observe the cells proliferation and collagen I synthesis. Methods Culture-activated HSC-T6 cells were divided into six groups: normal control group received no treatment; leptin group received recombinant rat leptin (100 ng/ml); the four intervention groups were pretreated with UA(50 μmol/L), JAK inhibitor AG490 (50 μmol/L), NOX inhibitor DPI(20 μmol/L), and ERK inhibitor PD98059 (30 μmol/L) for 30 min, and then stimulated with leptin for different time periods. Western blotting analysis was used to examined the expression of p47Phox protein translocation to the cell membrane, total cellular p47Phox protein and phosphorylated ERKl/2 (p-ERKl/2) protein. Collagen I mRNA expression was detected by RT-PCR and cell proliferation was examined by MTT assay. Results Expression of p47Phox membrane protein was significantly increased compared with the normal control 30 min after leptin stumulation (P<0. 01), and p-ERKl/2 protein expression was also significantly increased correspondingly (P<0. 05). UA, AG490, DPI and PD98059 inhibited the p47Phox protein translocation to membrane and ERKl/2 protein phosphorylation in HSC-T6 cells. Compared with normal control group, leptin stimulation for 12 h significantly up-regulated collagen I mRNA expression in HSC-T6 cells (P<0. 01); UA, AG490, DPI and PD98059 treatment inhibited collagen I mRNA expression in HSC-T6 cells compared with the leptin group (P<0. 01). Proliferation rates of HSC-T6 cells were significantly higher at 12, 24 and 48 h after leptin stimulation compared with the control group (all P<0. 01); UA, AG490, DPI and PD98059 treatment inhibited leptin-induced cell proliferation at different time points (all P<0. 01), with the inhibitory effect of UA being significantly weaker than that of DPI (P<0. 01). Conclusion UA can inhibit leptin-induced proliferation of HSC-T6 cells and collagen I expression, which might be associated with the inhibition of NOX subunit p47Phox translocation to the cell membrane and the ERK1/2 pathway activation.

Sorafenib inhibits the growth of human non-small cell lung cancer cells and induces their apoptosis / 肿瘤

Objective: To observe the effects of sorafenib on the proliferation and apoptosis of human non-small cell lung cancer (NSCLC) A549 and H1299 cells and to explore their possible mechanisms. Methods: The A549 and H1299 cells were treated with sorafenib at different concentrations. The inhibitory rate of cell proliferation was assessed by cell counting kit-8 (CCK-8). The apoptosis and the cell cycle distribution were analyzed by flow cytometry (FCM). The expression levels of phosphorylated extracellular signal-regulated kinase (p-ERK) and phosphorylated-Akt (p-Akt) proteins in A549 and H1299 cells were examined by Western blotting. Results: The proliferation of A549 and H1299 cells was inhibited via treatment with different concentrations of sorafenib in a dose-dependent manner (P<0.05). Sorafenib can induce apoptosis. The percentage of cells at G0/G1 phase was significantly increased, and which at S phase was significantly decreased in sorafenib-treated group, as compared with those in the control group (P<0.05). The expression level of p-ERK protein in A549 and H1299 cells treated with sorafenib was lower than that in the untreated control group (P<0.05). Conclusion: Sorafenib can inhibit the proliferation of human NSCLC A549 and H1299 cells and induce the apoptosis. This effect may be associated with the block of ERK signaling pathway. Copyright© 2011 by TUMOR.

ERK Phosphorylation and Indirect Activation of EGFR Induced by Homocysteine in Cerebellar Granule Neuron / 中国医科大学学报

Objective To study the relationship between extracellular signal-regulated kinases（ERK）phosphorylation and indirect activa-tion of the epidermal growth factor receptor（EGFR）in cultured cerebellar granule neurons induced by homocysteine.Methods We pri-marily cultured 7-day-old CD-1 mouse cerebellar granule neurons for 7 days and treated with different agents（saline,AG1478,Hcy and AG1478＋Hcy）.The phosphorylation of ERK was analyzed by Western blot,and apoptotic rate by flow cytometry.Results Compared with saline and AG1478 groups,the phosphorylation of ERK was increased in Hcy group（P 〈 0.05）.When we pretreated the cells with tyr-phostin AG1478,an inhibitor of EGFR,there was no difference in the activation of ERK compared with the control group.We found obvious neuronal apoptosis when 7-day-old CD-1 mouse cerebellar granule neurons were cultured for 7 days and treated with Hcy for 6 hours,and the apoptosis induced by Hcy was aggravated when the neurons were pretreated with AG1478（P 〈 0.05）.No apoptosis was found in the saline and AG1478 groups.Conclusion The role of Hcy on ERK activation suggests the involvement of an indirect activation process of EGFR,which has neural potentially protective effect.

Role of extracellular regulated kinase signal transduction pathway in the pathogenesis of acute necrotizing pancreatitis / 中华胰腺病杂志

Objective To investigate the changes of extraceUular regulated kinase 1/2 (ERK1/2) phosphorylation and assess the effects of blocking the ERK1/2 phosphorylation on rats with acute necrotizing pancreatitis (ANP). Methods The ANP model was induced by retrograde injection of 5% sodium tanrocholate into the biliary and pancreatic duct. 5 rats were treated as normal control. Other 75 Sprague-Dawley (SD) rots were randomly divided into sham operations(SO) group (n =25), ANP group (n =25) and PD98059 group (n =25). The rats were sacrificed at 15 min, 30 min, 1 h, 3 h and 6 h after ANP induction, the blood and pancreatic sample were taken. Pathological changes of pancreas were observed with light microscope and scored. The serum level of TNF-α and IL-1β was determined by ELISA. MPO activities in pancreas were measured by enzyme chemistry assay. Western blotting was performed to determine the phosphorylations of ERK1/2 in the pancreas homogenates. Results There was no significant pathologic changes in rats of SO group;but significant injuries occurred in ANP group, the pathologic score at 3 h was 9.9 ± 0.4;the extent of injuries attenuated in PD98059 group, the pathologic score at 3 h was 4.0 ± 0.4 (P < 0.05). The serum levels of TNF-α at 3 h in SO, ANP and PD98059 groups were (65.8 ± 20.5) pg/ml, (286.5 ± 50.3) pg/ml, (180.4±32.9)pg/ml, respectively;the serum levels of IL-1β at 3 h in SO, ANP and PD98059groups were (85.8 ± 25.5) pg/ml, (293.8 ± 46.3) pg/ml, (200. 5 ± 33.6) pg/ml, respectively;MPOactivities in pancreas were (0. 19 ± 0.02)U/g, (0.61±0.05)U/g, (0.52±0.03) U/g, and the values in ANP and PD98059 groups were significantly higher than those in SO group, while the values in PD98059 group were significantly lower than those in ANP group (P < 0.01). The expression of ERK1/2 phosphorylation in normal pancreas was 1100 ± 141, the expressions of ERK1/2 phosphorylation in ANP group at 15 min, 30 min were 5300 ± 486, 5621 ± 384, respectively;the expressions began to decrease 1 h later and returned the similar level as SO group at 6 h;the expressions of ERK1/2 phosphorylation in PD98059 group at 15 min, 30 rain were 4200 ± 370, 3600 ± 290, respectively;which were signifieanfly lower than those in ANP group (all P value < 0. 01). Conclusions The ERK1/2 signal transduetion pathway plays an important role in the pathogenesis of ANP. Inhibition of ERK1/2 phosphorylation by PD98059 may decrease the production of IL-1β, TNF-α and pancreatic MPO, attenuate the extent of pancreatic pathologic injuries.