Extra-cellular signal regulated kinase (ERK) signal transduction is an important signaling pathway, involved in a variety of processes in cell and is closely related with the occurrence of human cancers. By the application of dynamic method, the ERK signal pathway activated by epidermal growth factor receptor (EGFR) was simulated and analyzed in this work. The influence of the mutation of adaptor protein on the expression of phosphorylated ERK signal was analyzed, and the complex coupling of the protein kinases and their kinetic function were analyzed. The obtained results are helpful to understanding the mechanism of tumor development and to finding out new target molecules in the ERK signaling system.
Computer Simulation ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Humans ; Models, Biological ; Phosphorylation ; Receptor, Epidermal Growth Factor ; metabolism ; Signal Transduction

OBJECTIVETo compare the phosphorylation and protein expression of extracellular-signal regulated protein kinase (ERK) and P38 mitogen activated protein kinase (P38 MAPK) in the ejaculated spermatozoa of healthy volunteers and asthenospermia males, and to explore the correlation of ERK and P38 MAPK with human sperm motility.

METHODSSemen samples were collected from 20 healthy volunteers (sperm concentration > or = 20 x 10(6)/ml, grade a sperm > or = 25% or grade a + b sperm > or = 50%) and 20 infertile males with asthenospermia (sperm concentration > or = 20 x 10(6)/ml, grade a sperm < 25% and grade a + b sperm < or = 40%) and classified as a control and an asthenospermia group. Total protein in spermatozoa was extracted from all the subjects, and Western blotting was used to detect phosphorylation and protein expression levels of ERK and P38 MAPK.

RESULTSCompared with the control group, the protein expression levels of ERK and P38 MAPK and the phosphorylation level of P38 MAPK were significantly increased in the asthenospermia group (P < 0.05), but there were no statistically significant differences in the phosphorylation level of ERK between the two groups (P > 0.05).

CONCLUSIONThe up-regulated protein expressions of ERK and P38MAPK and increased phosphorylation level of P38 MAPK in human sperm may be involved in the pathogenesis of asthenospermia.

Asthenozoospermia ; metabolism ; Case-Control Studies ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Humans ; Male ; Phosphorylation ; Signal Transduction ; Sperm Motility ; Spermatozoa ; metabolism ; Up-Regulation ; p38 Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVESTo investigate the effects of FAK-related non-kinase (FRNK) on the apoptosis of hepatic stellate cells (HSC) in vitro and on the extracellular signal-regulated kinase (ERK) signal transduction pathway.

METHODSHSC were stimulated by fibronectin (FN), and then they were transfected with FAK-related non-kinase (FRNK) plasmids mediated by cationic liposome. The apoptosis of FRNK-induced HSC was examined by annexin-V/propidium iodide double-labeled flow cytometry (FCM), gel electrophoresis and transmission electron microscopy. Levels of FRNK, FAK, p-FAK (Tyr397), ERK1 and p-ERK in HSC were assayed by Western blot on the protein level, and by RT-PCR on the mRNA level.

RESULTSThe expression of FRNK was enhanced after FRNK plasmids were transiently transfected into the HSC. The apoptotic rate of the HSC exposed to FRNK plasmids for 48 h was higher than that in the non-FRNK plasmid group (25.37%+/-1.92% vs 9.28%+/-1.05%, P less than 0.01), and was accompanied by a significantly higher activity of caspase-3 both in the protein and in the mRNA levels [(264.17+/-12.60 vs 185.82+/-9.69), P less than 0.01; (4.19+/-0.48 vs 1.07+/-0.27), P less than 0.01]. After exposure of HSC to FRNK plasmids, compared with the non-FRNK plasmid group, the expressions of p-FAK, ERK1 and p-ERK in protein and mRNA levels were lower; on the contrary, compared with the control group, the expressions of p-FAK, ERK1 and p-ERK in the FN group were higher.

CONCLUSIONThe expression of FRNK was enhanced and the phosphorylation of FAK was inhibited after FRNK was transiently transfected into HSC in vitro. FRNK induces apoptosis of HSC. FAK-ERK signal transduction pathway perhaps is involved in the process.

Apoptosis ; Cell Line ; Cell Proliferation ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Hepatic Stellate Cells ; metabolism ; pathology ; Humans ; Protein-Tyrosine Kinases ; genetics ; metabolism ; RNA, Messenger ; genetics ; Signal Transduction

OBJECTIVETo investigate the expression of JAK, ERK and Cyclin D proteins in squamous-cell carcinoma of tongue.

METHODSThe expression of JAK, ERK and Cyclin D1 proteins was determined with SP immunohistochemical method in 30 cases of lingual Squamous cell carcinoma, 20 of normal lingual mucosa, 10 of mild epithelial dysplasia and 20 of severe epithelial dysplasia.

RESULTSThe expression of pJAK in lingual squamous-cell carcinoma and epithelial dysplasia was stronger than that of normal lingual mucosa (chi2=37.54, P<0.01), and the expression of pJAK in lingual squamous-cell carcinoma was significantly higher than that of the epithelial dysplasia (chi2=6.83, P<0.05). pJAK expression in squamous-cell carcinoma of low-middle differentiation was stronger than that of high differentiation. There was no significant difference in pERK expression among lingual squamous-cell carcinoma, normal lingual mucosa and epithelial dysplasia. There was a significantly positive correlation between pJAK and Cyclin D1 expression in SCC (r=0.619, P<0.05). There was no significant correlation between the expression of pERK and Cyclin D1 (r=0.231, P>0.05).

CONCLUSIONOver-expression of pJAK and Cyclin D1 may be associated with the occurrence and development of squamous-cell carcinoma of the tongue.

Carcinoma, Squamous Cell ; metabolism ; pathology ; Cyclin D1 ; metabolism ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Humans ; Immunohistochemistry ; Janus Kinases ; metabolism ; Phosphorylation ; Tongue Neoplasms ; metabolism ; pathology

OBJECTIVETo explore the effects of advanced oxidation protein products (AOPP) on expressions of stromal cell-derived factor-1alpha (SDF-1alpha) in ECV304 cells and the signal pathway that mediated the effects.

METHODSAOPP-BSA was made from bovine serum albumin (BSA) and sodium hypochlorite. After treated with AOPP-BSA of different concentrations (50, 100, 200 micromol/L), the expressions of SDF-1alpha mRNA in ECV304 cells were measured by reverse transcription-polymerase chain reaction (RT-PCR) and the expressions of SDF-1alpha protein and the levels of phosphorylated extracellular signal-regulated kinase (ERK) in ECV304 cells were analyzed by Western blot. In inhibition test, U0126, the special inhibitor of ERK of different concentrations (0.1, 1, 10 rmol/L) were added into ECV304 cells culture media for 1 hour, then the cells were treated with AOPP-BSA for 24 hours, at last the protein levels in supernatant were detected by enzyme-linked immunosorbent assay (ELISA).

RESULTSAOPP-BSA obviously promoted the expressions of SDF-1alpha mRNA and increased the levels of SDF-1beta protein of ECV304 cells in dose-dependent manner (all P < 0.01), after 15 minutes treated with 200 micromol/L AOPP-BSA, the levels of phosphorylated ERK of ECV304 cells increased significantly (P < 0.01). When the ERK pathway was blocked by U0126, the promoting effects of AOPP-BSA on expressions of SDF-la protein in ECV304 cells were significantly inhibited in dose-dependent manner (P < 0.05).

CONCLUSIONAOPP induced the expression of SDF-la of ECV304 cells, ERK signal pathway is an important pathway that mediated the effects.

Advanced Oxidation Protein Products ; pharmacology ; Cell Line ; Chemokine CXCL12 ; metabolism ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Humans ; MAP Kinase Signaling System ; Oxidative Stress ; Phosphorylation ; RNA, Messenger ; genetics

OBJECTIVETo study the possible anti-apoptotic mechanism of ginsenoside Rg1 on the apoptosis of hippocampal neuron after cerebral ischemia/reperfusion (I/R) injury rats.

METHODSTotally 120 healthy male adult SD rats were randomly divided into the cerebral I/R model group (the model group), the low dose ginsenoside Rg1 group (10 mg/kg), the middle dose ginsenoside Rg1 group (20 mg/kg), the high dose ginsenoside Rg1 group (40 mg/kg), and the sham-operation group, 18 in each group. Rats received medication by peritoneal injection. Equal volume of normal saline was peritoneally injected to rats in the sham-operation group and the model group, once daily, for 7 successive days. The cerebral I/R injury model was prepared by 2-h middle cerebral artery occlusion (MCAO) followed by 24-h reperfusion. Rats in the sham-operation group received the same surgical procedure without the carotid arteries occluded. The neurofunction was assessed using Longa EZ method. The injury of hippocampal pyramidal cells was observed by Nissel staining and TUNEL assay. The nerve cell apoptosis rate was calculated. The protein expression levels of extracellular signal-regulated kinase 1/2 (ERK1/2), phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2), c-Jun N-terminal kinases (JNK), and phosphorylated c-Jun N-terminal kinase (p-JNK) were detected using Western blot.

RESULTSCompared with the sham-operation group, the score of neurofunction, the apoptosis rate, the expression levels of p-JNK and p-ERK1/2 increased, the survived number of pyramidal cells decreased in the model group (P < 0.05, P < 0.01). Compared with the model group, the score of neurofunction and the apoptosis rate decreased in each ginsenoside Rg1 group (P < 0.05, P < 0.01). The survived number of pyramidal cells increased in the high and middle dose ginsenoside Rg1 groups, the expression of p-JNK in the hippocampal CA1 region decreased, and the expression level of p-ERK1/2 increased (P < 0.05, P < 0.01). Compared with the low dose ginsenoside Rg1 group, the score of neurofunction, the apoptosis rate, the p-JNK protein expression decreased, the survived number of pyramidal cells increased, the expression of p-ERK1/2 increased in the high and middle dose ginsenoside Rg1 groups (P < 0.05, P < 0.01). Three to four layers of pyramidal cells were arranged tightly and compactly in the hippocampal CA1 region of the sham - operation group. The nucleus was big and round under high power lens, with 1 -2 kernel. After cerebral I/R injury, the hippocampal nerve cells were severely injured. Normal structure was lost in the CA1 region, with disarranged cell line and reduced cell amount. Partial neurons were shrunken, and the kernel was condensed and darkenedly stained. They were in triangular, long strip, fusiform, or irregular shape. The staining of nucleus was clustered and the kernel was not clear. Ginsenoside Rg1 (20 and 40 mg/kg) could improve the morphology of ischemic nerve cells, reduce their loss. Of them, stronger effects were shown in the high dose ginsenoside Rg1 group than in the middle dose ginsenoside Rg1 group. The JNK protein band was divided into two subzones, JNK1 (46 kD) and JNK2 (54 kD). ERK protein band was also divided into two subzones, ERK1 (44 kD) and ERK2 (42 kD).

CONCLUSIONThe protective effect of ginsenoside Rg1 on cerebral I/R injury was correlated with inhibiting the apoptosis of hippocampal neurons, regulating the expression levels of p-ERK1/2 and p-JNK.

Animals ; Brain Ischemia ; metabolism ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Ginsenosides ; pharmacology ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; metabolism

BACKGROUNDPreviously, we reported that dual-specificity phosphatase 1 (DUSP1) was differentially expressed in endometrioid adenocarcinoma (EEA). However, the role of DUSP1 in EEA progression and the relationship between DUSP1 and medroxyprogesterone (MPA) are still unclear.

METHODSThe expression of DUSP1 in EEA specimens was detected by immunohistochemical analysis. The effect of DUSP1 on cell proliferation was analyzed by Cell Counting Kit 8 and colony formation assay, and cell migration was analyzed by transwell assay. MPA-induced DUSP1 expression in EEA cells was measured by Western blot.

RESULTSDUSP1 expression was deficient in advanced International Federation of Gynecology and Obstetrics stage, high-grade and myometrial invasive EEA. In EEA cell lines (Hec1A, Hec1B, RL952, and Ishikawa), the DUSP1 expression was substantially higher in Ishikawa cells than in other cell lines (P < 0.05). Knockdown of DUSP1 promoted Ishikawa cells proliferation, migration, and activation of mitogen-activated protein kinases/extracellular signal-regulated kinase (MAPK/Erk) pathway. MPA-induced DUSP1 expression and inhibited MAPK/Erk pathway in Ishikawa cells.

CONCLUSIONSOur data suggest that DUSP1 deficiency promotes EEA progression via MAPK/Erk pathway, which may be reversed by MPA, suggesting that DUSP1 may serve as a potential therapeutic target for the treatment of EEA.

Carcinoma, Endometrioid ; metabolism ; Cell Culture Techniques ; Cell Proliferation ; genetics ; physiology ; Dual-Specificity Phosphatases ; genetics ; metabolism ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Female ; Humans ; Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVEMicroRNAs (miRNAs or miRs) play critical roles in the fibrotic process in different organs. We summarized the latest research progress on the roles and mechanisms of miRNAs in the regulation of the molecular signaling pathways involved in fibrosis.

DATA SOURCESPapers published in English from January 2010 to August 2015 were selected from the PubMed and Web of Science databases using the search terms "microRNA", "miR", "transforming growth factor β", "tgf β", "mitogen-activated protein kinase", "mapk", "integrin", "p38", "c-Jun NH2-terminal kinase", "jnk", "extracellular signal-regulated kinase", "erk", and "fibrosis".

STUDY SELECTIONArticles were obtained and reviewed to analyze the regulatory effects of miRNAs on molecular signaling pathways involved in the fibrosis.

RESULTSRecent evidence has shown that miRNAs are involved in regulating fibrosis by targeting different substrates in the molecular processes that drive fibrosis, such as immune cell sensitization, effector cell activation, and extracellular matrix remodeling. Moreover, several important molecular signaling pathways involve in fibrosis, such as the transforming growth factor-beta (TGF-β) pathway, mitogen-activated protein kinase (MAPK) pathways, and the integrin pathway are regulated by miRNAs. Third, regulation of the fibrotic pathways induced by miRNAs is found in many other tissues in addition to the heart, lung, liver, and kidney. Interestingly, the actions of many drugs on the human body are also induced by miRNAs. It is encouraging that the fibrotic process can be blocked or reversed by targeting specific miRNAs and their signaling pathways, thereby protecting the structures and functions of different organs.

CONCLUSIONSmiRNAs not only regulate molecular signaling pathways in fibrosis but also serve as potential targets of novel therapeutic interventions for fibrosing diseases.

Animals ; Extracellular Signal-Regulated MAP Kinases ; genetics ; metabolism ; Fibrosis ; genetics ; metabolism ; Humans ; MicroRNAs ; genetics ; Mitogen-Activated Protein Kinases ; genetics ; metabolism ; Transforming Growth Factor beta ; genetics ; metabolism

OBJECTIVETo study the differentiation potential of human umbilical cord-derived mesenchymal stem cells (UCMSC) into human sweat gland cells (hSGC) and the role of extracellular signal-regulated kinase (ERK) pathway.

METHODSUCMSC and hSGC were isolated and cultured in vitro. The former was identified with expression of CD14, CD29, CD34, CD44, CD45, CD105, cytokeratin 7 (CK7), CK19, and carcinoembryonic antigen (CEA), while the latter was identified with expression of CK19 and CEA. UCMSC with density of 5 x 10(4) cells per well placed in lower compartment of Transwell chamber were divided into control group (C, cultured with nutrient solution without any stimulation), thermal injury group (TI, treated with heat-shocked hSGC with density of 1 x 10(4) cells per well inoculated into the upper compartment of Transwell chamber for indirect co-culture), thermal injury + EGF group (TIE, treated with indirect co-culture as used in TI group, with addition of 50 ng/mL EGF), thermal injury + PD98059 group (TIP, treated with indirect co-culture as used in TI group, with addition of 10 nmol/mL ERK specific inhibitor PD98059) according to the random number table. One week after culture, the positive expression rates of CK7 and CK19 in UCMSC were detected by flow cytometry, the expression of CK19 and CEA in UCMSC were examined with immunohistochemical staining and the positive expression rate of CEA was calculated, and the expression level of phosphorylated ERK (pERK) was determined by Western blotting. Data were processed with one-way analysis of variance.

RESULTS(1) CD29, CD44, and CD105 were highly expressed in UCMSC, accompanied by low or negative expression of CD14, CD34, CD45, CK7, CK19, and CEA. The expression of CK19 and CEA were positive in hSGC. The two results showed that UCMSC and hSGC were pure. (2) Compared with those of C group [(2.2 +/- 1.5)%, (2.2 +/- 0.7)%, (3.3 +/- 0.7)%, 0.640 +/- 0.026], the expression levels of CK7, CK19, CEA, and pERK in UCSMC of TI group [(6.4 +/- 0.7)%, (5.7 +/- 0.3)%, (7.4 +/- 1.0)%, 0.790 +/- 0.049] and TIE group [(14.3 +/- 1.0)%, (12.6 +/- 1.1)%, (17.6 +/- 2.3)%, 1.200 +/- 0.032] were significantly increased (with F value respectively 78.49, 139.36, 87.13, and 191.74, P values all below 0.01), and those of TIE group were higher than those of TI group (with F value from 50.14 to 145.47, P values all below 0.01). There were no obvious difference in the 4 indexes between TIP group and C group (with F value from 0.00 to 0.13, P values all above 0.05).

CONCLUSIONSUCMSC co-cultured with heat-shocked hSGC can differentiate into hSGC, and ERK signal pathway participates in the process of differentiation of UCMSC into hSGC.

Cell Differentiation ; Cells, Cultured ; Extracellular Signal-Regulated MAP Kinases ; Flow Cytometry ; Humans ; Mesenchymal Stromal Cells ; cytology ; metabolism ; Signal Transduction ; Sweat Glands ; cytology ; metabolism ; Umbilical Cord ; cytology ; metabolism

Embryonic stem (ES) cells hold great promise in regenerative medicine and it is an urgent task to understand the underlying molecular mechanisms that control ES cell fate choice between self-renewal and differentiation. In mouse ES cells, extrinsic leukemia inhibitory factor (LIF) and bone morphogenetic protein (BMP) signaling pathways play pivotal roles in maintaining the self-renewal status under serum and feeder free culture conditions. Intrinsic extracellular-signal regulated kinase (ERK) activity is also important in determining mouse ES cell fate-low ERK activity keeps mouse ES cell self-renewal while high ERK activity drives differentiation. We recently found that while LIF signaling augments ERK activity, BMP signaling inhibits ERK activity in mouse ES cells via direct upregulation of an ERK phosphatase-dual-specificity phosphatase 9. The cooperative effects of LIF and BMP signaling keep appropriate ERK activity and maintain mouse ES cell self-renewal (Li et al., 2012). These findings shed light on how extrinsic signals converge to intrinsic signaling molecules to regulate cell fate determination. This perspective summarizes our recent new findings and discusses the current unsolved questions and future directions.
Animals ; Bone Morphogenetic Proteins ; metabolism ; Embryonic Stem Cells ; enzymology ; metabolism ; Extracellular Signal-Regulated MAP Kinases ; antagonists & inhibitors ; metabolism ; Humans ; Mice ; Signal Transduction