Mitogen-activated protein kinase signaling pathway and invasion and metastasis of gastric cancer

The mortality rate of gastric cancer worldwide is as high as 70%, despite the development of novel therapeutic strategies. One reason for the high mortality is the rapid and uninhibited spread of the disease, such that the majority of patients are diagnosed at a stage when efficient therapeutic treatment is not available. Therefore, in-depth research is needed to investigate the mechanism of gastric cancer metastasis and invasion to improve outcomes and provide biomarkers for early diagnosis. The mitogen-activated protein kinase(MAPK) signaling pathway is widely expressed in multicellular organisms, with critical roles in multiple biological processes, such as cell proliferation, death, differentiation, migration, and invasion. The MAPK pathway typically responds to extracellular stimulation. However, the MAPK pathway is often involved in the occurrence and progression of cancer when abnormally regulated. Many studies have researched the relationship between the MAPK signaling pathway and cancer metastasis and invasion, but little is known about the important roles that the MAPK signaling pathway plays in gastric cancer. Based on an analysis of published data, this review aims to summarize the important role that the MAP kinases play in the invasion and metastasis of gastric cancer and attempts to provide potential directions for further research and clinical treatment.

Electroacupuncture reduces apoptotic index and inhibits p38 mitogen-activated protein kinase signaling pathway in the hippocampus of rats with cerebral ischemia/reperfusion injury

Electroacupuncture attenuates cerebral hypoxia and neuronal apoptosis induced by cerebral ischemia/reperfusion injury.To further identify the involved mechanisms,we assumed that electroacupuncture used to treat cerebral ischemia/reperfusion injury was associated with the p38 mitogen-activated protein kinase（MAPK） signaling pathway.We established rat models of cerebral ischemia/reperfusion injury using the modified Zea-Longa＇s method.At 30 minutes before model establishment,p38 MAPK blocker SB20358 was injected into the left lateral ventricles.At 1.5 hours after model establishment,electroacupuncture was administered at acupoints of Chize（LU5）,Hegu（LI4）,Zusanli（ST36）,and Sanyinjiao（SP6） for 20 minutes in the affected side.Results showed that the combination of EA and SB20358 injection significantly decreased neurologic impairment scores,but no significant differences were determined among different interventional groups.Hematoxylin-eosin staining also showed reduced brain tissue injuries.Compared with the SB20358 group,the cells were regularly arranged,the structures were complete,and the number of viable neurons was higher in the SB20358 ＋ electroacupuncture group.Terminal deoxynucleotidyl transferase（Td T）-mediated d UTP nick-end labeling assay showed a decreased apoptotic index in each group,with a significant decrease in the SB20358 ＋ electroacupuncture group.Immunohistochemistry revealed reduced phosphorylated p38 expression at 3 days in the electroacupuncture group and SB20358 ＋ electroacupuncture group compared with the ischemia/reperfusion group.There was no significant difference in phosphorylated p38 expression between the ischemia/reperfusion group and SB20358 group.These findings confirmed that the electroacupuncture effects on mitigating cerebral ischemia/reperfusion injury are possibly associated with the p38 MAPK signaling pathway.A time period of 3 days could promote the repair of ischemic cerebral nerves.

Effects of Dendrobium candidum polysaccharides on microRNA-125b and mitogen-activated protein kinase signaling pathways in diabetic cataract rats

Background:Diabetic cataract is a common complication and a lens disorder in diabetes.Moreover,Dendrobium officinale polysaccharide(DOP)is found to alleviate diabetes complications.Consequently,microRNA-125b and mitogen-activated protein kinase signaling pathways play significant roles in diabetes.However,the mechanism and the effect of DOP on diabetic cataract remains unknown.Methods:Wistar male rats were randomly assigned to the control,model,and DOP groups.Diabetes was induced with streptozotocin.Furthermore,DOP was orally given for 12 weeks.The Lens Opacities Classification System III was used to evaluate lens opacity by slit-lamp microscope.The lens was then harvested for testing the mRNA expression of microRNA-125b,ERK1,ERK2,Raf and Ras using reverse transcription-polymerase chain reaction.The protein expression of ERK1,ERK2,Raf,and Ras was detected using the Western blot analysis.The targets of microRNA-125b were predicted in miRWalk 2.0.These targets were obtained from the Kyoto Encyclopedia of Genes and Genomes pathway.Results:The lens opacities of the rats in the control group were almost at C0N0.Moreover,the majority of the lens opacities in the model group were C3 to C4 and N1 to N2,and were mostly at C1 to C2 and N0 to N1 in the DOP group.The difference was statistically significant(P<0.05).Furthermore,the microRNA-125b expression in the model group is significantly higher compared with the control group.Conversely,the microRNA-125b expression in the DOP group is significantly decreased(all P<0.05).The mRNA expression of ERK1,ERK2,Raf,and Ras in the model groups were upregulated compared with those of the control group.However,the ERK1 and Raf mRNA expressions of the DOP group were lower compared with the model group(all P<0.05).The protein expression of ERK1,Raf,and Ras in the model group was significantly increased compared with those of the control group.The protein expression of ERK1,Raf,and Ras in the DOP group was significantly lower compared with the model group(all P<0.05).Moreover,3,378 genes of the microRNA-125b target were gained from the miRWalk.After Kyoto Encyclopedia of Genes and Genomes pathways analysis in Gene Set Enrichment Analysis,246 items were gained including Ras(rno04014)and mitogen-activated protein kinase(rno04010)signaling pathways.A positive correlation exists between microRNA-125b and mRNA expression of ERK1,ERK2,Raf and Ras(r=0.940,0.841,0.666,and 0.768;all P<0.05).Conclusion:DOP can alleviate the severity of the opacity of the lens in diabetic cataract rats via microRNA-125b and mitogen-activated protein kinase signaling pathways.Thus,microRNA-125b has something to do with the mitogen-activated protein kinase signaling pathway.

Electroacupuncture stimulating Zusanli(ST36),Sanyinjiao(SP6)in mice with collagen-induced arthritis leads to adenosine A2A receptor-mediated alteration of p38αmitogen-activated protein kinase signaling and inhibition of osteoclastogenesis

OBJECTIVE:To observe the effect of electroacupuncture(EA)stimulating Zusanli(ST36),Sanyinjiao(SP6)on inhibition of osteoclastogenesis and the role of the adenosine A2A receptor(A2AR)and the p38αMitogen-Activated Protein Kinase(MAPK)signaling pathway in mediating this effect.METHODS:Mice with collagen induced arthritis(CIA)received different treatments.Immunohistochemistry and western blotting were used to determine the levels of multiple signaling molecules in these joints[receptor activator of nuclear transcription factor-κB(NF-κB)ligand(RANKL),receptor activator of NF-κB(RANK),tumor necrosis factor receptor associated factor 6(TRAF6),p38α,NF-κB,and nuclear factor of activated T cells C1(NFATc1)].Osteoclasts were identified using tartrate-resistant acid phosphatase(TRAP)staining.RESULTS:The immunohistochemistry results indicated upregulation of p38α,NF-κB,and NFATc1 in the CIA-control and CIA-EA-SCH58261 groups,but reduced levels in the CIA-EA group.Western blotting indicated upregulation of RANKL,RANK,TRAF6,p38α,NF-κB,and NFATc1 in the CIA-control and CIA-EA-SCH58261 groups,but reduced expression in the CIA-EA group.Osteoclasts were more abundant in the CIA-control and CIA-EA-SCH58261 groups than in the CIA-EA group.CONCLUSIONS:EA treatment enhanced the A2AR activity and inhibited osteoclast formation by inhibition of RANKL,RANK,TRAF6,p38α,NF-κB,and NFATc1.SCH58261 reversed the effect of EA.These results suggest that EA regulated p38α-MAPK signaling by increasing A2AR activity,which inhibited osteoclastogenesis.

Pingchuan formula(平喘方) improves allergic asthma in mice through inhibiting nuclear factor-kappa B/mitogen-activated protein kinase signaling pathway

OBJECTIVE:To examine the role and decipher the mechanism of Pingchuan formula(平喘方,PCF)in treating allergic asthma.METHODS:The mice were treated with saline,dexamethasone(DXM)and PCF for 1 week after the asthma model was established and their respiratory function including respiratory resistance(RI),pulmonary dynamic compliance(Cdyn)and maximum voluntary ventilation(MVV)were measured.In addition,cellular changes in bronchoalveolar lavage fluid(BALF)and pathological changes in lung biopsy as well as the expression level ofα-smooth muscle actin(α-SMA),transforming growth factor-beta1(TGF-β1)in BALF and interleukin-5(IL-5),interleukin-13(IL-13),tumor necrosis factor-α(TNF-α),interferon-γ(IFN-γ),nuclear factor-kappa B-p65(NF-κBp65),inhibitor-αof nuclear transcription factorκB(IκBα),p38 mitogen-activated protein kinase(p38 MAPK),c-jun n-terminal kinase(JNK)and its phosphorylated proteins in lung tissue were also examined and compared among different groups.RESULTS:Our data suggested that the respiratory functions were significantly improved and the pathological changes ameliorated in the DXM group and the PCF group compared to the model group.Both DXM and PCF effectively decreased the number of eosinophils,lymphocytes,and neutrophils in BAL as well as the secretion ofα-SMA and TGF-β1,IL-5,IL-13,while increased the expression of TNF-αand IFN-γ.Furthermore,our study indicated that the NF-κBp65,IκBα,p38 MAPK and JNK pathways were inhibited under the treatment of PCF.CONCLUSION:Our data indicated that PCF can attenuate the inflammatory response in asthma through inhibiting the NF-κB/MAPK signaling pathway.This study not only supported the use of PCF in allergic asthma in clinic but also shed light upon afurther understanding of the disease pathogenesis.

A new cell death program regulated by toll-like receptor 9 through p38 mitogen-activated protein kinase signaling pathway in a neonatal rat model with sepsis associated encephalopathy

Background:Sepsis,a serious condition with high mortality,usually causes sepsis associated encephalopathy(SAE)that involves neuronal cell death.However,the cell death programs involved and their underlying mechanisms are not clear.This study aimed to explore the regulatory mechanisms of different cell death programs in SAE.Methods:A neonatal rat model of SAE was established by cecal ligation and perforation.Survival rate and vital signs(mean arterial pressure and heart rate)were monitored,nerve reflexes were evaluated,and cortical pathological changes were observed by hematoxylin and eosin staining.The expression of pyroptosis,apoptosis,and necroptosis(PANoptosis)-related proteins,mitogen-activated protein kinase(MAPK),and its upstream regulator toll-like receptor 9(TLR9)were detected.The expression of TLR9 in neurons was observed by immunofluorescence staining.The ultrastructure of neurons was observed by transmission electron microscope.Results:First,PANoptosis was found in cortical nerve cells of the SAE rats.Meanwhile,the subunits of MAPKs,p38 MAPK,Jun N-terminal kinase,and extracellular signal-regulated kinase(ERK)were activated.After pharmacologically inhibiting each of the subunits,only p38 MAPK was found to be associated with PANoptosis.Furthermore,blocking the p38 MAPK signaling pathway activated necroptosis but inhibited apoptosis and pyroptosis.When necroptosis was pharmacologically inhibited,apoptosis and pyroptosis were reactivated.Finally,we found that the expression of TLR9,a regulator of MAPKs,was significantly increased in this model.After down-regulation of TLR9,p38 MAPK,and ERK signaling pathways were inhibited,which led to the inhibition of PANoptosis.Further analysis found that down-regulation of TLR9 improved the survival rate and reduced the pathological changes in SAE rats.Conclusions:Our study showed that the programs comprising PANoptosis are activated simultaneously in SAE rats.TLR9 activated PANoptosis through the p38 MAPK signaling pathway.TLR9 may work as a potential target for SAE treatment.

Genome-wide identification of the mitogen-activated protein kinase kinases in pear and their functional analysis in response to black spot

The mitogen-activated protein kinase(MAPK)cascade is crucial to plant growth,development,and stress responses.MAPK kinases(MAPKK)play a vital role in linking upstream MAPKK kinases(MAPKKK)with the downstream MAPK.Black spot is one of the most serious fungal diseases of pear which is an important part of the fruit industry in China.The MAPKK genes have been identified in many plants,however,none has been reported in pear(Pyrus bretschneideri).In order to explore whether MAPK gene of pear is related to black spot disease,we designed this experiment.The present study investigated eight putative PbrMAPKK genes obtained from the Chinese white pear genome.The phylogenetic analysis revealed that PbrMAPKK genes were divided into A,B,C,and D groups.These PbrMAPKK genes are randomly distributed on 7 out of 17 chromosomes and mainly originated from the whole-genome duplication(WGD)event.The expression analysis of PbrMAPKK genes in seven pear tissues and the leaves of susceptible and resistant varieties after Alternaria alternata infection by quantitative real-time PCR(qRT-PCR)identified seven candidate genes associated with resistance.Furthermore,virus-induced gene silencing(VIGS)indicated that PbrMAPKK6 gene enhanced resistance to pear black spot disease in pear.

Follistatin-Like 1 Promotes Bleomycin-lnduced Pulmonary Fibrosis through the Transforming Growth Factor Beta 1/Mitogen-Activated Protein Kinase Signaling Pathway

Background： Follistatin-like I （FSTL 1） is a novel profibrogenic factor that induces pulmonary fibrosis （PF） through the transforming growth factor-beta 1 （TGF-[B 1 ）/Smad signaling. Little is known about its effects on PF through the non-Smad signaling, like the mitogen-activated protein kinase （MAPK） pathway. Therefore, this study aimed to investigate the role ofFSTL 1 in PF through the MAPK signaling pathway and its mechanisms in lung fibrogenesis. Methods： PF was induced in Fstll~ and wild-type （WT） C57BL/6 mice with bleomycin. After 14 days, the mice were sacrificed, and lung tissues were stained with hematoxylin and eosin; the hydroxyproline content was measured to confirm PF. The mRNA and protein level of FSTLI and the change of MAPK phosphorylation were measured by quantitative polymerase chain reaction and Western blotting. The effect of Fst11 deficiency on fibroblasts differentiation was measured by Western blotting and cell immunofluorescence. MAPK signaling activation was measured by Western blotting in Fst11＋/ and WT fibroblasts treated with recombinant human FSTLI protein. We pretreated mouse lung fibroblast cells with inhibitors of the extracellular signal-regulated kinase （ERK）, p38, and Jun N-terminal kinase （JNK） signaling and analyzed their differentiation, proliferation, migration, and invasion by Western blotting, 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide analysis, and transwell assays. The Student＇s t-test was used to compare the differences between two groups. Results： Fstll deficiency attenuated phosphorylation of the ERK, p38, and JNK signaling in bleomycin-induced fibrotic lung tissue 14 days after injury （0.67 ± 0.05 vs. 1.22 ± 0.03, t = 14.92, P = 0.0001; 0.41 ± 0.01 vs. 1.15 ± 0.07; t = 11.19; P = 0.0004; and 0.41 ± 0.01 vs. 1.07± 0.07, t = 8.92, P = 0.0009; respectively）, compared with WT lungs at the same time and in primary lung fibroblasts （0.82 ± 0.01 vs. 1.01 ±0.04, t = 4.06, P = 0.0150; 1.04 ±0.03 vs. 1.24 ± 0.03, t= 4.44, P = 0.0100： and 0.76 ±0.05 vs. 0.99± 0.05, t = 4.48, P = 0.0100; respectively）, compared with TGF-β1-stimulated WT group. Recombinant human FSTLI protein in lung fibroblasts enhanced TG F-β1 -mediated phosphorylation of the ERK （ 1.19± 0.08 vs, 0.55 ± 0.04, t = 6.99, P = 0.0020）, p38 （ 1.18 ±0.04 vs. 0.66 ± 0.03, t = 11.20, P = 0.0020）, and .INK （ 1,11± 0.01 vs. 0.84 ± 0.04, t = 6.53, P = 0.0030）, compared with the TGF-β1-stimulated WT group. Fstll-deficient fibroblasts showed reduced alpha-smooth muscle actin （α-SMA） expression （0.70 ± 0.06 vs. 1.28 ±0.11, t = 4.65, P = 0.0035, compared with the untreated WT group; 1.40 ± 0.05 vs. 1.76± 0.02, t = 6.31, P = 0.0007; compared with the TGF-β1-treated WT group）. Compared with the corresponding condition in the control group, the TGF-β1/FSTL 1-mediated α-SMA expression was significantly suppressed by pretreatment with an inhibitor of p38 （0.73± 0.01 vs. 1.13 ± 0.10, t = 3.92, P = 0.0078） and JNK （0.78 ± 0.03 vs. 1.08 ± 0.06, t = 4.40,P = 0.0046） signaling. The proliferation of mouse lung fibroblast cells （MLgs） significantly decreased after treatment of an inhibitor of p38 （0.30 ±0.01 vs. 0.46 ±0.03, t = 4.64, P = 0.0009）, JNK （0.30 ± 0.01 vs. 0.49 ± 0.01, t = 12.84, P = 0.0001）, and Smad2/3 （0.18 ± 0.02 vs. 0.46 ±0.02, t = 12.69, P = 0.0001） signaling compared with the dimethylsulibxide group. The migration and invasion cells of MLgs significantly decreased in medium pretreated with an inhibitor of p38 （70.17 ±3.28 vs. 116.30 ± 7.11, t = 5.89, P = 0.0042 for the migratory cells; 19.87 ± 0.84 vs. 32.70 i 0.95, t =10.14, P = 0.0005 for the invasive cells）, JNK （72.30 ±3.85 vs. 116.30 ± 7.11, t = 5.44, P = 0.0056 for the migratory cells; 18.03 ± 0.94 vs. 32.70 ± 0.95, t = 11.00, P = 0.0004 for the invasive cells）, and Smad2/3 （64.76 ± 1.41 vs. 116.30 ± 7.11, t = 7.11, P = 0.0021 for the migratory cells; 18.03 ± 0.94 vs. 32.70 ±0.95, t = 13.29, P = 0.0002 for the invasive cells） signaling compared with the corresponding condition in the dimethylsulfoxide group. Conclusion： FSTL1 affects lung fibroblast differentiation, proliferation, migration, and invasion through p38 and JNK signaling, and in this way, it might influence the development of PF.

Cyclovirobuxinum D Alleviates Cardiac Hypertrophy in Hyperthyroid Rats by Preventing Apoptosis of Cardiac Cells and Inhibiting the p38 Mitogen-Activated Protein Kinase Signaling Pathway

Objective： To investigate the underlying mechanisms of cyclovirobuxinum D（Cvb-D） on alleviating cardiac hypertrophy in rats. Methods： Sprague-Dawley rats were randomly divided into 5 groups： control group; levothyroxine-induced cardiac hypertrophy group（model）; levothyroxine-induced cardiac hypertrophy ＋ Cvb-D group（Cvb-D）; levothyroxine-induced cardiac hypertrophy ＋ captopril group（captopril）; levothyroxine-induced cardiac hypertrophy ＋ SB203580 group（SB203580）, n=10 for each group. Rats were daily administered the respective drugs continuously for14 days by gastric gavage. A rat model of cardiac hypertrophy was established by intraperitoneal injection of levothyroxine to investigate whether Cvb-D protects against cardiac hypertrophy by inhibiting the p38 mitogen-activated protein kinase（MAPK） signaling pathway and preventing apoptosis of cardiac cells. Results： Treatment with Cvb-D significantly deceased left ventricle hypertrophy, improved the histopathology, hemodynamic conditions, and cardiac function in rats with cardiac hypertrophy. Compared with the normal control group, in rats with cardiac hypertrophy, expression of bax in the heart and phospho-p38 MAPK protein levels were significantly up-regulated（P〈0.01 or 0.05）, whereas the bcl-2 protein level was downregulated（P〈0.01）. In contrast, Cvb-D treatment reversed the changes in bax and phospho-p38 MAPK protein levels but increased the bcl-2 protein level（P〈0.01 or 0.05）, and these effects were similar to those of captopril and SB203580（a specific p38 MAPK inhibitor） treatment. Furthermore, both Cvb-D, captopril and SB203580 reduced m RNA expression of p38α, p38β, c-fos, and c-jun m RNA, and Cvb-D had a stronger effect（P〈0.01）. Conclusion： These results demonstrate that Cvb-D protects against cardiac hypertrophy, which is possibly mediated by prevention of cardiac cell apoptosis and inhibition of the p38 MAPK signaling pathway.

Buyang Huanwu Tang(补阳还五汤) protects H_(2)O_(2)-induced RGC-5 cell against oxidative stress and apoptosis via reactive oxygen species-mitogen-activated protein kinase signaling pathway

OBJECTIVE: To study the molecular mechanism of Buyang Huanwu Tang( 补阳还五汤)(BHT) protecting retinal ganglion cells(RGCs) from oxygen induced oxidative stress and apoptosis after anterior ischemia. METHODS: In this study, the Chinese herbs of BHT were extracted by first boiling in water, then were filtered, concentrated, and freeze-dried. The chemical profile of BHT extract was determined by liquid chromatography mass spectrometry(LC-MS). H2O2-induced RGC-5 cells were used as a cell model to investigate the protective effect and mechanism of BHT on RGCs. RESULTS: The survival rate of damaged RGC-5 by BHT was significantly increased by the 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazolium-romid method. Fluorescence activating cell sorter(FACS analysis) showed that BHT could significantly reduce apoptosis induced by oxidative stress via the reactive oxygen species(ROS)-mitogen-activated protein kinase(MAPK)-Caspase-3 signal pathway. CONCLUSION: BHT possesses a high antioxidant capacity and could significantly reduce ROS levels of RGC-5 cells damaged by H2O2.Therefore, the present study has provided possible alternative strategies for the prevention and treatment of ischemic optic disease by using traditional Chinese herbal formulas.

Electroacupuncture attenuates chronic salpingitis via transforming growth factor-β1/p38 mitogen-activated protein kinase signaling pathway

OBJECTIVE:To explore the effect of electroacupuncture(EA)on rats with chronic fallopian tube inflammation and its potential mechanisms.METHODS:Thirty-six female Sprague-Dawley rats were divided into Control,Model and EA groups.The pathological morphology of the fallopian tubes was observed by hematoxylin-eosin(HE)and Masson staining.The results of transforming growth factor-β1(TGF-β1),P38 mitogen-activated protein kinase(MAPK),phosphorylation(p)-p38MAPK in rat oviduct tissues were detected by immunohistochemistry.Results of P38MAPK,p-P38MAPK and TGF-β1 in rat oviduct tissues were detected by immunofluorescence.The expression level of p38MAPK,p-P38MAPK,TGF-β1 protein in rats was detected by Western blot.Quantitative real-time polymerase chain reaction(RT-q PCR)was used to detect m RNA expression levels of TGF-β1.RESULTS:It found that collagen fibers counts decreased significantly in EA group compared to Model group.The phosphorylation of P38MAPK in EA group was significantly reduced compared to Model group.The serum TGF-β1 expressions in EA group increased decreased significantly.CONCLUSION:Electroacupuncture was able to attenuate chronic salpingitis through down-regulating TGF-β1/MAPK signaling pathway.

Neuroprotective Effects of Raloxifene on Aβ_(25-35)-induced Damages in PC12 Cells via Mitogen-activated Protein Kinase Signaling Pathway

Objective To investigate the neuroprotective effects and the mechanism of this protection of raloxifene （RLX）, a selective estrogen receptor modulator.Methods MTT assay and flow cytometry with annexin V-FITC/PI staining were performed to evaluate the neuroprotective effects of RLX on Aβ25-35-induced toxicity. The potential mechanisms were studied by Western blotting in cultured rat pheochromocytoma cells （PC12 cells）.Results RLX（1 000 nmol/L）, in combination with Aβ25-35 （30 llmol/L）, increased the cell viability （P 〈0.001）, and reduced the number of apoptotic cells （P 〈0.05）. RLX attenuated Aβ25-35-induced loss of △ψm （P 〈0.01）. The changing of △ψm was similar to the variation of apoptosis. PD98059 （inhibitor of ERK1/2） inhibited the effects of RLX on cell viability and phosphorylation of cleaved caspase-9. No significant difference of cell viability or phosphorylation of cleaved caspase-9 had been found when PC12 cells were incubated with SB203580 （inhibitor of p38MAPK） or SP600125 （inhibitor of JNK）. Afl25.35 induced a time-dependent phosphorylation of p38MAPK and JNK. In PC12 cells treated solely with RLX, ERK1/2 was activated （P〈0.01）. In PC12 cells treated with Aβ25-35 and RLX, Aβ2545-induced phosphorylation of p38MAPK and JNK were inhibited （P〈0.01 and P〈0.001, respectively）.Conclusion RLX inhibited Af125.35-induced cell apoptosis by activating the ERK1/2 pathway in PC12 cells. RLX also attenuated Aβ25-35-induced activation of p38MAPK and JNK. The mitochondria pathway Was involved in this inhibitory effect.

MicroRNA-370-5p inhibits pigmentation and cell proliferation by downregulating mitogen-activated protein kinase kinase kinase 8 expression in sheep melanocytes

In mammals,microRNAs(miRNAs)play key roles in multiple biological processes by regulating the expression of target genes.Studies have found that the levels of miR-370-5p expression differ significantly in the skins of sheep with different hair colors;however,its function remains unclear.In this study,we investigated the roles of miR-370-5p in sheep melanocytes and found that the overexpression of miR-370-5p significantly inhibited cell proliferation(P<0.01),tyrosinase activity(P=0.001)and significantly reduced(P<0.001)melanin production.Functional prediction revealed that the 3′-untranslated region(UTR)of MAP3K8 has a putative miR-370-5p binding site,and the interaction between these two molecules was confirmed using luciferase reporter assays.In situ hybridization assays revealed that MAP3K8 is expressed in the cytoplasm of melanocytes.The results of quantitative RT-PCR and Western blotting analyses revealed that overexpression of miR-370-5p in melanocytes significantly inhibits(P<0.01)MAP3K8 expression via direct targeting of its 3′UTR.Inhibition of MAP3K8 expression by siRNA-MAP3K8 transfection induced a significant inhibition(P<0.01)of melanocyte proliferation and significant reduction(P<0.001)in melanin production,which is consistent with our observations for miR-370-5p.Target gene rescue experiments indicated that the expression of MAP3K8 in melanocytes co-transfected with miR-370-5p and MAP3K8-cDNA(containing sites for the targeted binding to miR-370-5p)was significantly rescued(P≤0.001),which subsequently promoted significant increases in cell proliferation(P<0.001)and melanin production(P<0.01).Collectively,these findings indicate that miR-370-5p plays a functional role in inhibiting sheep melanocyte proliferation and melanogenesis by downregulating the expression of MAP3K8.

Xingshentongqiao Decoction Mediates Proliferation, Apoptosis, Orexin-A Receptor and Orexin-B Receptor Messenger Ribonucleic Acid Expression and Represses Mitogen-activated Protein Kinase Signaling

Background：Hypocretin （HCRT） signaling plays an important role in the pathogenesis of narcolepsy and can be significantly influenced by Chinese herbal therapy.Our previous study showed that xingshentongqiao decoction （XSTQ） is clinically effective for the treatment of narcolepsy.To determine whether XSTQ improves narcolepsy by modulating HCRT signaling,we investigated its effects on SH-SY5Y cell proliferation,apoptosis,and HCRT receptor 1/2 （orexin receptor 1 [OXl R] and orexin receptor 2 [OX2R]） expression.The signaling pathways involved in these processes were also assessed.Methods：The effects of XSTQ on proliferation and apoptosis in SH-SY5Y cells were assessed using cell counting kit-8 and annexin V-fluorescein isothiocyanate assays.OX1R and OX2R expression was assessed by quantitative real-time polymerase chain reaction analysis.Western blotting for mitogen-activated protein kinase （MAPK） pathway activation was performed to further assess the signaling mechanism of XSTQ.Results：XSTQ reduced the proliferation and induced apoptosis of SH-SY5Y cells.This effect was accompanied by the upregulation of OX 1R and OX2R expression and the reduced phosphorylation of extracellular signal-regulated kinase （Erk） 1/2,p38 MAPK and c-Jun N-terminal kinase （JNK）.Conclusions：XSTQ inhibits proliferation and induces apoptosis in SH-SY5Y cells.XSTQ also promotes OX1R and OX2R expression.These effects are associated with the repression of the Erkl/2,p38 MAPK,and JNK signaling pathways.These results define a molecular mechanism for XSTQ in regulating HCRT and MAPK activation,which may explain its ability to treat narcolepsy.

Osteopontin promotes gastric cancer progression via phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin signaling pathway

BACKGROUND Gastric cancer(GC)is one of the most common malignant tumors.Osteopontin(OPN)is thought to be closely related to the occurrence,metastasis and prognosis of many types of tumors.AIM To investigate the effects of OPN on the proliferation,invasion and migration of GC cells and its possible mechanism.METHODS The mRNA and protein expression of OPN in the GC cells were analyzed by realtime quantitative-reverse transcription polymerase chain reaction and western blotting,and observe the effect of varying degree expression OPN on the proliferation and other behaviors of GC.Next,the effects of OPN knockdown on GC cells migration and invasion were examined.The short hairpin RNA(shRNA)and negative control shRNA targeting OPN-shRNA were transfected into the cells according to the manufacturer’s instructions.Non transfected cells were classified as control in the identical transfecting process.24 h after RNA transfection cell proliferation activity was detected by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-diphenytetrazoliumromide assay,and cell invasiveness and migration were detected by Trans well assay.Meanwhile,the expression of protein kinase B(AKT),matrix metalloproteinase 2(MMP-2)and vascular endothelial growth factor(VEGF)in the human GC cell lines was detected by reverse transcription polymerase chain reaction and western blotting.RESULTS The results of this study revealed that OPN mRNA and protein expression levels were highly expressed in SGC-7901 cells.OPN knockdown by specific shRNA noticeably reduced the capabilities of proliferation,invasion and migration of SGC-7901 cells.Moreover,in the experiments of investigating the underlying mechanism,results showed that OPN knockdown could down-regulated the expression of MMP-2 and VEGF,it also decreased the phosphorylation of AKT.Meanwhile,the protein expression levels of MMP-2,VEGF and phosphorylated AKT was noticeable lower than that in control group in the GC cells after they were added to phosphatidylinositol-3-kinase(PI3K)inhibitor(LY294002).CONCLUSION These results suggested that OPN though PI3K/AKT/mammalian target of rapamycin signal pathway to upregulate MMP-2 and VEGF expression,which contribute SGC-7901 cells to proliferation,invasion and migration.Thus,our results demonstrate that OPN may serve as a novel prognostic biomarkers as well as a potential therapeutic targets for GC.

Huangqi decoction(黄芪汤) attenuates renal interstitial fibrosis via transforming growth factor-β1/mitogen-activated protein kinase signaling pathways in 5/6 nephrectomy mice

OBJECTIVE: To investigate the effect of Huangqi decoction( 黄芪汤) on renal interstitial fibrosis and its association with the transforming growth factor-β1(TGF-β1)/mitogen-activated protein kinase(MAPK) signaling pathway. METHODS: 120 C57/BL mice were randomly divided into six groups: sham group, Enalapril(20 mg/kg) group, 5/6 nephrectomy model group, and 5/6 nephrectomy model plus Huangqicoction(0.12, 0.36 and 1.08 g/kg respectively) groups. Detecting 24hours urinary protein, blood pressure, serum creatinine, urea nitrogen content changes. Periodic Acid-Schiff stain(PAS) and Masson’s trichrome staining was used to observe the renal tissue pathological changes. Protein expression of TGF-β1, Phosphorylated P38 mitogen activated protein kinases(P-P38), Phosphorylated c-jun N-terminal kinase(P-JNK), Phosphorylated extracellular regulated proteinhnase(PERK), Fibroblast-specific protein-1(FSP-1), Alpha smooth muscle actin(α-SMA), Type Ⅲ collagen(Collagen Ⅲ), Connective tissue growth factor(CTGF),Bcl-2 Assaciated X protein(Bax) and B cell lymphoma 2(Bcl-2) were measured with western blot and immunohistochemical. RESULTS: Both Huangqi decoction and Enalapril improved the kidney function, 24 h urinary protein and the fibrosis in 5/6 nephrectomy mice, Huangqi decoction downregulated the expressions of TGF-β1, FSP-1, α-SMA, Collagen Ⅲ and CTGF in a dose-dependent manner, and it has a significant difference(P < 0.01) compared with model group.Huangqi decoction downregulated the expressions of P-P38, P-JNK, P-ERK and Bcl-2 in a dose-dependent manner, while upregulated the expression of Bax. CONCLUSIONS: The protective effect of Huangqi decoction for renal interstitial fibrosis in 5/6 nephrectomized mice via the inhibition of EpithelialMesenchymal Transitions and downregulating the TGF-β1/MAPK signaling pathway.

Increased expression of mitogen-activated protein kinase and its upstream regulating signal in human gastric cancer

AIM: To investigate the expression of mitogen-activated protein kinases (MAPKs) and its upstream protein kinase in human gastric cancer and to evaluate the relationship between protein levels and clinicopathological parameters.METHODS: Westem blot was used to measure the expression of extracellular signal-regulated kinase (ERK)-1, ERK-2, ERK-3,p38 and mitogen or ERK activated protein kinaseMEK-1proteins in surgically resected gastric carcinoma, adjacent normal mucosa and metastatic lymph nodes from 42 patients.Immunohistochemistry was employed for their localization.RESULTS: Compared with normal tissues, the protein levels of ERK-1 (integral optical density value 159 526±65 760 vs122 807±65 515, P = 0.001), ERK-2 (168 471±95 051 vs120 469±72 874, P＜0.001), ERK-3 (118 651±71 513 vs70 934±68 058, P＜0.001), P38 (104 776±51 650 vs82 930±40 392, P= 0.048) and MEK-1(116 486±45 725 vs101 434±49 387, P = 0.027) were increased in gastric cancer tissues. Overexpression of ERK-3 was correlated to TNM staging [average ratio of integral optic density (IOD)tumor:IODnormal in TNM Ⅰ, Ⅱ, Ⅲ, Ⅳ tumors was 1.43±0.34,5.08±3.74, 4.99±1.08, 1.44±1.02, n = 42, P = 0.023] and serosa invasion (4.31±4.34 vs 2.00±2.03, P = 0.037). In poorly differentiated cancers (n = 33), the protein levels of ERK-1 and ERK-2 in stage Ⅲ and Ⅳ tumors were higher than those in stage Ⅰ and Ⅱ tumors (2.64±3.01 vs 1.01±0.33,P = 0.022; 2.05±1.54 vs 1.24±0.40, P = 0.030). Gastric cancer tissues with either lymph node involvement (2.49±2.91vs 1.03±0.36, P= 0.023; 1.98±1.49 vs 1.24±0.44, P= 0.036)or serosa invasion (2.39±2.82 vs 1.01±0.35, P = 0.022;1.95±1.44 vs 1.14±0.36, P = 0.015) expressed higher protein levels of ERK-1 and ERK-2. In Borrmann Ⅱ tumors,expression of ERK-2 and ERK-3 was increased compared with Borrmann Ⅲ tumors (2.57±1.86 vs 1.23±0.60, P = 0.022;5.50±5.05 vs 1.83±1.21, P = 0.014). Borrmann Ⅳ tumors expressed higher p38 protein levels. No statistically significant difference in expression of MAPKs was found when stratified to tumor size or histological grade (P＞0.05).Protein levels of ERK-2, ERK-3 and MEK-1 in metastatic lymph nodes were 2-7 folds higher than those in adjacent normal mucosa. The immunohistochemistry demonstrated that ERK-1, ERK-2, ERK-3, p38 and MEK-1 proteins were mainly localized in cytoplasm. The expression of MEK-1 in gastric cancer cells metastasized to lymph nodes was higher than that of the primary site.CONCLUSION: MAPKs, particularly ERK subclass are overexpressed in the majority of gastric cancers.Overexpression of ERKs is correlated to TNM staging, serosa invasion, and lymph node involvement. The overexpression of p38 most likely plays a prominent role in certain morphological subtypes of gastric cancers. MEK-1 is also overexpressed in gastric cancer, particularly in metastatic lymph nodes. Upregulation of MAPK signal transduction pathways may play an important role in tumorigenesis and metastatic potential of gastric cancer.

Jiawei Wendan decoction affects mitogen-activated protein kinase signal pathway in the hippocampus of depression rats

A previous study from our group showed that Jiawei Wendan decoction inhibits protein expression of interleukin-1β, 2, and 6, as well as plasma neuropeptide Y, P substance and somatostatin in the hippocampus of depression rat models. The present study analyzed the influence of Jiawei Wendan decoction on the mitogen-activated protein kinase signal transduction pathway in the hippocampus. Results demonstrated that Jiawei Wendan decoction effectively upregulated expression of small molecular G proteins, extracellular regulated kinase 1/2, and activated ribosomal S6 kinase protein in the rat hippocampus. In addition, Jiawei Wendan decoction exhibits antidepressant effects similar to fluoxetine. The underlying mechanisms were shown to be dependent on increased mitogen-activated protein kinase signal transduction pathway activity.

Influence of electroacupuncture on mitogen-activated protein kinase signal transduction in a rat model of cerebral ischemia/reperfusion

Following electroacupuncture at Baihui （DU 20） and Dazhui （DU 14） in a rat model of cerebral ischemia/reperfusion, extracellular-signal-regulated kinase expression in cerebral cortex and corpus striatum, serum glutathione reductase, glutathione peroxidase activity, and serum glutathione content were elevated, and neurobehavioral scores improved. However, these effects were antagonized by mitogen-activated protein kinase inhibitor PD98059. Results indicated that electroacupuncture reversed free radical chain reactions and oxidative stress injury caused by cerebral ischemia/reperfusion, thereby providing neuroprotection. This process could correlate with the mitogen-activated protein kinase signal transduction pathway.

Effects of Mitogen-activated Protein Kinase Signal Pathway on Heat Shock Protein 27 Expression in Human Lens Epithelial Cells Exposed to Sodium Salicylate in vitro

The roles of mitogen-activated protein kinase （MAPK） signal pathway in sodium salieylate-induced expression of heat shock protein 27 （HSP27） in human lens epithelial cells （HLECs-B3） in vitro were investigated. HLECs-B3 were incubated in the fresh media containing sodium salicylate at different concentrations for different durations, and allowed to be recovered in fresh medium without sodium salicylate for different durations with or without pretreatment with p38MAPK inhibitor （SB203580）, ERK1/2 inhibitor （PD98059） and JNK/SAPK inhibitor （SP600125）. The expression of P38MAPK, ERK1/2, JNK/SAPK, phosphorylated P38MAPK, phosphorylated ERK1/2, phosphorylated JNK/SAPK and HSP27 was detected by Western blot. The expression of HSP27 mRNA and protein was detected by RT-PCR and immunohistochemistry respectively. It was found there was only weak expression of HSP27 in normal HLECs. The expression of HSP27 was not detectable in HLECs-B3 that were exposed to sodium salicylate （55 retool/L） for 1-5 h. It was indicated that recovery from sodium salicylate （〉35 mmol/L） significantly increased the synthesis of HSP27. The expression of HSP27 was up-regulated in HLECs-B3 under sodium salicylate recovery for 3 h, reached the peak level for 6 h, and returned to the level of control cells by 24 h. Activation of P38MAPK from sodium salicylate stimulation occurred at 30th rain, and increased significantly at 1st h, then declined and renamed to baseline level at 3rd h under sodium salicylate recovery. Activation of ERK1/2 occurred at 1st h and reached the peak level at 6th h under sodium salicylate recovery. However, JNK/SAPK was inactivated by sodium salicylate. The expression of HSP27 could be down-regulated with the pretreatment of SB203580 and PD98059 jointly. It is concluded that sodium salicylate can induce the expression of HSP27 in HLECs-B3. The effects are mediated, at least in part, through the activation of P38MAPK and ERK1/2 signaling pathway.