Mitogen-activated protein kinase phosphatase 1 protects PC12 cells from amyloid beta-induced neurotoxicity

The mitogen-activated protein kinase（MAPK） signaling pathway plays an important role in the regulation of cell growth, proliferation, differentiation, transformation and death. Mitogen-activated protein kinase phosphatase 1（MKP1） has an inhibitory effect on the p38 MAPK and JNK pathways, but it is unknown whether it plays a role in Aβ-induced oxidative stress and neuronal inflammation. In this study, PC12 cells were infected with MKP1 sh RNA, MKP1 lentivirus or control lentivirus for 12 hours, and then treated with 0.1, 1, 10 or 100 μM amyloid beta 42（Aβ42）. The cell survival rate was measured using the cell counting kit-8 assay. MKP1, tumor necrosis factor-alpha（TNF-α） and interleukin-1β（IL-1β） m RNA expression levels were analyzed using quantitative real time-polymerase chain reaction. MKP1 and phospho-c-Jun N-terminal kinase（JNK） expression levels were assessed using western blot assay. Reactive oxygen species（ROS） levels were detected using 2′,7′-dichlorofluorescein diacetate. Mitochondrial membrane potential was measured using flow cytometry. Superoxide dismutase activity and malondialdehyde levels were evaluated using the colorimetric method. Lactate dehydrogenase activity was measured using a microplate reader. Caspase-3 expression levels were assessed by enzyme-linked immunosorbent assay. Apoptosis was evaluated using the terminal deoxynucleotidyl transferase d UTP nick end labeling method. MKP1 overexpression inhibited Aβ-induced JNK phosphorylation and the increase in ROS levels. It also suppressed the Aβ-induced increase in TNF-α and IL-1β levels as well as apoptosis in PC12 cells. In contrast, MKP1 knockdown by RNA interference aggravated Aβ-induced oxidative stress, inflammation and cell damage in PC12 cells. Furthermore, the JNK-specific inhibitor SP600125 abolished this effect of MKP1 knockdown on Aβ-induced neurotoxicity. Collectively, these results show that MKP1 mitigates Aβ-induced apoptosis, oxidative stress and neuroinflammation by inhibiting the JNK signaling pathway, thereby playing a neuroprotective role.

Overexpression of mitogen-activated protein kinase phosphatase-1 in endothelial cells reduces blood-brain barrier injury in a mouse model of ischemic stroke

Ischemic stroke can cause blood-brain barrier(BBB)injury,which worsens brain damage induced by stroke.Abnormal expression of tight junction proteins in endothelial cells(ECs)can increase intracellular space and BBB leakage.Selective inhibition of mitogen-activated protein kinase,the negative regulatory substrate of mitogen-activated protein kinase phosphatase(MKP)-1,improves tight junction protein function in ECs,and genetic deletion of MKP-1 aggravates ischemic brain injury.However,whether the latter affects BBB integrity,and the cell type-specific mechanism underlying this process,remain unclear.In this study,we established an adult male mouse model of ischemic stroke by occluding the middle cerebral artery for 60 minutes and overexpressed MKP-1 in ECs on the injured side via lentiviral transfection before stroke.We found that overexpression of MKP-1 in ECs reduced infarct volume,reduced the level of inflammatory factors interleukin-1β,interleukin-6,and chemokine C-C motif ligand-2,inhibited vascular injury,and promoted the recovery of sensorimotor and memory/cognitive function.Overexpression of MKP-1 in ECs also inhibited the activation of cerebral ischemia-induced extracellular signal-regulated kinase(ERK)1/2 and the downregulation of occludin expression.Finally,to investigate the mechanism by which MKP-1 exerted these functions in ECs,we established an ischemic stroke model in vitro by depriving the primary endothelial cell of oxygen and glucose,and pharmacologically inhibited the activity of MKP-1 and ERK1/2.Our findings suggest that MKP-1 inhibition aggravates oxygen and glucose deprivation-induced cell death,cell monolayer leakage,and downregulation of occludin expression,and that inhibiting ERK1/2 can reverse these effects.In addition,co-inhibition of MKP-1 and ERK1/2 exhibited similar effects to inhibition of ERK1/2.These findings suggest that overexpression of MKP-1 in ECs can prevent ischemia-induced occludin downregulation and cell death via deactivating ERK1/2,thereby protecting the integrity of BBB,alleviating brain injury,and improving post-stroke prognosis.

A role for mitogen-activated protein kinase phosphatase 1(MKP1) in neural cell development and survival

The mitogen-activated protein kinase（MAPK）pathways are a group of conserved intracellular signalling pathways present in most cells including neurons and glia.These pathways respond to a variety of stimuli including growth factors,cytokines and oxidative stress to generate appropriate cellular responses such as modulation of gene expression,cell proliferation,differentiation and survival as well as the stress response（Korhonen and Moilanen,2014）.

Retinoic Aacid Diminished the Expression of MMP-2 in Hyperoxia-exposed Premature Rat Lung Fibroblasts through Regulating Mitogen-activated Protein Kinases

This study examined the effects of retinoic acid （RA）, PD98059, SP600125 and SB203580 on the hyperoxia-induced expression and regulation of matrix metalloproteinase-2 （MMP-2） and metalloproteinase-2 （TIMP-2） in premature rat lung fibroblasts （LFs）. LFs were exposed to hyperoxia or room air for 12 h in the presence of RA and the kinase inhibitors PD98059 （ERK1/2）, SP600125 （JNK1/2） and SB203580 （p38） respectively. The expression levels of MMP-2 and TIMP-2 mRNA were detected by semi-quantitative reverse transcription polymerase chain reaction （RT-PCR）. MMP-2 activity was measured by zymography. The amount of p-ERK1/2, REK1/2, p-JNK1/2, JNK1/2, p-p38 and p38 was determined by Western blotting. The results showed that： （1） PD98059, SP600125 and SB203580 significantly inhibited p-ERK1/2, p-JNK1/2 and p-p38 respectively in LFs; （2） The expression of MMP-2 mRNA in LFs exposed to hyperoxia was decreased after treatment with RA, SP600125 and SB203580 respectively （P0.01 or 0.05）, but did not change after treatment with PD98059 （P0.05）. Meanwhile, RA, PD98059, SP600125 and SB203580 had no effect on the expression of TIMP-2 mRNA in LFs exposed to room air or hyperoxia （P0.05）; （3） The expression of pro- and active MMP-2 experienced no change after treatment with RA or SP600125 in LFs exposed to room air （P0.05）, but decreased remarkably after hyperoxia （P0.01 or 0.05）. SB203580 inhibited the expression of pro- and active MMP-2 either in room air or under hyperoxia （P0.01）. PD98059 exerted no effect on the expression of pro- and active MMP-2 （P0.05）. It was suggested that RA had a protective effect on hyperoxia-induced lung injury by down-regulating the expression of MMP-2 through decreasing the JNK and p38 activation in hyperoxia.

Bacteroides fragilis enterotoxin upregulates heme oxygenase-1 in dendritic cells via reactive oxygen species-,mitogen-activated protein kinase-,and Nrf2-dependent pathway

BACKGROUND Enterotoxigenic Bacteroides fragilis(ETBF)causes colitis and diarrhea,and is considered a candidate pathogen in inflammatory bowel diseases as well as colorectal cancers.These diseases are dependent on ETBF-secreted toxin(BFT).Dendritic cells(DCs)play an important role in directing the nature of adaptive immune responses to bacterial infection and heme oxygenase-1(HO-1)is involved in the regulation of DC function.AIM To investigate the role of BFT in HO-1 expression in DCs.METHODS Murine DCs were generated from specific pathogen-free C57BL/6 and Nrf2−/−knockout mice.DCs were exposed to BFT,after which HO-1 expression and the related signaling factor activation were measured by quantitative RT-PCR,EMSA,fluorescent microscopy,immunoblot,and ELISA.RESULTS HO-1 expression was upregulated in DCs stimulated with BFT.Although BFT activated transcription factors such as NF-κB,AP-1,and Nrf2,activation of NF-κB and AP-1 was not involved in the induction of HO-1 expression in BFT-exposed DCs.Instead,upregulation of HO-1 expression was dependent on Nrf2 activation in DCs.Moreover,HO-1 expression via Nrf2 in DCs was regulated by mitogenactivated protein kinases such as ERK and p38.Furthermore,BFT enhanced the production of reactive oxygen species(ROS)and inhibition of ROS production resulted in a significant decrease of phospho-ERK,phospho-p38,Nrf2,and HO-1 CONCLUSION These results suggest that signaling pathways involving ROS-mediated ERK and p38 mitogen-activated protein kinases-Nrf2 activation in DCs are required for HO-1 induction during exposure to ETBF-produced BFT.

Regulation of Ikaros function by casein kinase 2 and protein phosphatase 1

The Ikaros gene encodes a zinc finger,DNA-binding protein that regulates gene transcription and chromatin remodeling.Ikaros is a master regulator of hematopoiesis and an established tumor suppressor.Moderate alteration of Ikaros activity (e.g.haploinsufficiency) appears to be sufficient to promote malignant transformation in human hematopoietic cells.This raises questions about the mechanisms that normally regulate Ikaros function and the potential of these mechanisms to contribute to the development of leukemia.The focus of this review is the regulation of Ikaros function by phosphorylation/dephosphorylation.Site-specific phosphorylation of Ikaros by casein kinase 2 (CK2) controls Ikaros DNA-binding ability and subcellular localization.As a consequence,the ability of Ikaros to regulate cell cycle progression,chromatin remodeling,target gene expression,and thymocyte differentiation are controlled by CK2.In addition,hyperphosphorylation of Ikaros by CK2 leads to decreased Ikaros levels due to ubiquitinmediated degradation.Dephosphorylation of Ikaros by protein phosphatase 1 (PP1) acts in opposition to CK2 to increase Ikaros stability and restore Ikaros DNA binding ability and pericentromeric localization.Thus,the CK2 and PP1 pathways act in concert to regulate Ikaros activity in hematopoiesis and as a tumor suppressor.This highlights the importance of these signal transduction pathways as potential mediators of leukemogenesis via their role in regulating the activities of Ikaros.

Phosphoprotein Phosphatase 1 Isoforms Alpha and Gamma Respond Differently to Prodigiosin Treatment and Present Alternative Kinase Targets in Melanoma Cells

Reversible protein phosphorylation is a central regulatory mechanism of cell function. Deregulation of the balanced actions of protein kinases and phosphatases has been frequently associated with several pathological conditions, including cancer. Many studies have already addressed the role of protein kinases misregulation in cancer. However, much less is known about protein phosphatases influence. Phosphoprotein Phosphatase 1 (PPP1) is one of the major serine/threonine protein phosphatases who has three catalytic isoforms: PPP1CA, PPP1CB, and PPP1CC. Its function is achieved by binding to regulatory subunits, known as PPP1-interacting proteins (PIPs), which may prefer a catalytic isoform. Also, some inhibitors/enhancers may exhibit isoform specificity. Here we show that, prodigiosin (PG), a molecule with anticancer properties, promotes the formation of PPP1CA-AKT complex and not of PPP1CC-MAPK complex. Both, AKT and MAPK, are well-known PIPs from two pathways that crosstalk and regulate melanoma cells survival. In addition, the analysis performed using surface plasmon resonance (SPR) technology indicates that PPP1 interacts with obatoclax (OBX), a drug that belongs to the same family of PG. Overall, these results suggest that PG might, at least in part, act through PPP1C/PIPs. Also, this study is pioneer in demonstrating PPP1 isoform-specific modulation by small molecules.

Activation of p38 mitogen-activated protein kinase contribute to BMP4-induced alkaline phosphatase expression in MC3T3-E1 preosteoblast

Bone morphogenetic proteins （BMPs） induce ectopic bone formation and promote osteoblast differentiation. It has been documented that Smad transcriptional factors function as primary mediators of BMPs activity. Receptor-regulated Smad （Smad1, 5, 8） could be phosphorylated by activated BMPR-I and form complex with Smad4. The Smad complex translocates to the nucleus and regulate target gene transcription. Recently, several reports suggested that Mitogen-Activated Protein Kinase （MAPK） signaling pathways could be initiated downstream of the BMP receptor complex. Alkaline phosphatase （ALP） is an early marker of osteoblast differentiation Both ALP activity and its mRNA expression level could be increased by BMP4 treatment. Previously, we demonstrated that mutation of ERK1/2 phosphorylation sites in Smad5 partially rescued Smad transcriptional activity. However, fibroblast growth factor2-suppressed ALP activity could not be rescued similarly by introduction of Smad5 mutant in MC3T3-E1. These results prompted us to further evaluate the effect of BMP4-stimulated Smad transcriptional activity on ALP expression in this study.

Involvement of MAPK/ERK kinase-ERK pathway in exogenous bFGF-induced Egr-1 binding activity enhancement in anoxia-reoxygenation injured astrocytes

Objective Intravenous administration of basic fibroblast growth factor （bFGF） is effective to reduce the volume of cerebral infract due to ischemia. This study was designed to investigate the molecular mechanism, especially the signal transduction pathways, involved in this protective role of bFGF. Methods Anoxia-reoxygenation treated atrocytes were used to study the role of mitogen-activated protein kinase/extracellular signal-regulated kinase kinase （MAPK/ERK kinase, MEK）-ERK signaling pathway after exogenous bFGF administration by Western blot. Electrophoretic mobile shift assay was used to detect the binding activity of early growth response factor-1 （Egr-1）, an important transcription factor for endogenous bFGF. Results bFGF could protect some signal transduction proteins from the oxygen-derived free radicals induced degradation. ERK1/2 was activated and involved in Egr-1 binding activity enhancement induced by exogenous bFGF. Conclusion MEK-ERK MAPK cascade may be an important signal transduction pathway contributed to bFGF induced enhancement of Egr-1 binding activity in anoxia-reoxygenation injured astrocytes.

Involvement of ERK1/2 and p38 MAPK in up-regulation of 14-3-3 protein induced by hydrogen peroxide preconditioning in PC12 cells

Objective To investigate the protective effects of hydrogen peroxide preconditioning （HPP） on the pheochromocytoma （PC12） cells treated with 1-methyl-4-phenylpyridinium （MPP^＋） and to explore the potential mechanisms. Methods The viability and apoptosis of PC 12 cells were determinded by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay and 4′,6′-diamidino-2-phenylindole （DAPI） staining, respectively. The expressions of 14-3-3 protein and phospholylated p38 mitogen-activated protein kinase （MAPK） were determined by Western blot. Enzyme-linked immunosorbent assay （ELISA） was used to measure the activity of extracellular signal-regulated protein kinase 1/2 （ERK1/2）. Results The cell viability decreased and the number of apoptotic cells increased dramatically in MPP^＋ group compared with that in Control group. HPP induced a significant increase in cell viability and a marked decrease in population of apoptotic cells of the MPP^＋- treated PC 12 cells, accompanied with up-regulation of 14-3-3 protein and increase of ERK 1/2 and p38 MAPK activities. The 14-3-3 protein expression was positively correlated with the phosphorylation of ERK1/2. Furthermore, inhibition of the ERK1/2 with PD98059 abolished the 14-3-3 protein up-regulation in PC 12 cells induced by HPP. Conclusion HPP protects PC 12 cells against MPP＋ toxicity by up-regulating 14-3-3 protein expression through the ERK1/2 and p38 MAPK signaling pathways.

红景天苷对类风湿关节炎患者血清脯氨酸羟化酶2及蛋白磷酸酯酶2A和丝裂原活化蛋白激酶表达水平的影响

目的分析红景天苷对类风湿关节炎(RA)患者血清脯氨酸羟化酶2(PHD2)及蛋白磷酸酯酶2A(PP2A)和丝裂原活化蛋白激酶(MAPK)表达水平的影响。方法选取青海省中医院2022年12月至2023年7月收治的RA患者96例。采用随机数字表法分为对照组和观察组,各48例。对照组采用常规西医治疗,观察组在常规西医治疗的同时予以红景天苷治疗,2组均治疗3个月。比较治疗前后2组中医证候评分、临床症状与体征、实验室检查指标[包括红细胞沉降率(ESR)、C反应蛋白(CRP)、类风湿因子(RF)、抗环瓜氨酸肽抗体(anti-CCP)]、临床疗效,健康状况评定量表(HAQ)与28个关节疾病活动度评估(DAS28)评分,血清PHD2、PP2A、MAPK水平与基因表达,不良反应。结果治疗后2组主症、次症评分均低于治疗前且观察组均低于对照组(均P<0.05)。治疗后观察组临床症状与体征均轻于对照组,ESR、CRP、RF和anti-CCP水平均低于对照组(均P<0.05)。观察组总有效率高于对照组[95.8%(46/48)比80.4%(37/46)](P=0.020)。治疗后观察组HAQ与DAS28评分均低于对照组[(5.0±1.0)分比(7.2±1.2)分、(3.1±0.5)分比(4.1±0.7)分](t=9.528、7.444,均P<0.001)。治疗后观察组PHD2、MAPK水平及基因表达均低于对照组,PP2A水平及基因表达均高于对照组,差异均有统计学意义(均P<0.05)。2组不良反应发生率差异无统计学意义(P=0.528)。结论红景天苷治疗RA可增强临床效果、减轻患者症状、改善实验室指标且安全。推测与降低PHD2和MAPK表达、增加PP2A表达有关。

Mitogen-activated protein kinase-dependent apoptosis in norcan-tharidin-treated A375-S2 cells is proceeded by the activation of protein kinase C

We have reported that norcantharidin (NCTD) induces human melanoma A375-S2cell apoptosis and that the activation of caspase and the mitochondrial pathway are involved in theapoptotic process. This study aimed at investigating the roles of mitogen-activated protein kinase(MAPK) and protein kinase C (PKC) in A375-S2 cell apoptosis induced by NCTD. We assessed theeffects of NCTD on cell growth inhibition using the 3-(4,5-dimethylthiazol-2-yl)-2 ,5-dipheyltetrazolium bromide ( MTT) assay, DNA fragmentation ( DNA agarose gel electrophoresis ) ,and MAPK protein levels (Western blot analysis) in A375-S2 cells. Photomicroscopic data were alsocollected. The NCTD inhibitory effect on A375-S2 cells was partially reversed by MAPK and PKCinhibitors. The expression of phosphorylated JNK and p38 also increased after the treatment withNCTD, and inhibitors of c-Jun NH2 - terminal kinase (JNK) and p38 ( SP600125 and SB203580,respectively) had significant inhibitory effects on the upregulation of phosphorylated JNK and p38expression. Simultaneously, the PKC inhibitor staurosporine blocked the upregulation ofphosphorylated JNK and phosphorylated p_(38), but had little effect on extracellularsignal-regulated kinase (ERK) expression. These results suggest that the activation of JNK andp_(38) MAPK promotes the process of NCTD-induced A375-S2 cell apoptosis and that PKC plays animportant regulation role in the activation of MAPKs.

A cotton mitogen-activated protein kinase (GhMPK6) is involved in ABA-induced CAT1 expression and H_2O_2 production

The mitogen-activated protein kinase （MAPK） cascade is one of the a pivotal role in the regulation of stress and developmental signals in plants. major and evolutionally conserved signaling pathways and plays Here, we identified one gene, GhMPK6, encoding an MAPK protein in cotton. GFP fluorescence assay demonstrated that GhMAPK6 is a cytoplasm localized protein. Quantitative RT-PCR analysis revealed that mRNA accumulation of GhMPK6 was significantly promoted by abscisic acid （ABA）. Overexpression of GhMPK6 gene in the T-DNA insertion mutant atmkkl （SALK_015914） conferred a wild-type phenotype to the transgenic plants in response to ABA. Under ABA treatment, cotyledon greening/expansion in GhMPK6 transgenic lines and wild type was significantly inhibited, whereas the atmkkl mutant showed a relatively high cotyledon greening/expansion ratio. Furthermore, CAT1 expression and H2O2 levels in leaves of GhMPK6 transgenic lines and wild type were remarkably higher than those of atmkkl mutant with ABA treatment. Collectively, our results suggested that GhMPK6 may play an important role in ABA-induced CAT1 expression and H2O2 production.

Mitogen-activated protein kinase-activated protein kinase 2 regulates tumor necrosis factor-induced interleukin-6 expression via human antigen R

Background Human antigen R （HuR） is a ubiquitously expressed member of the ELAV family, and has relatively high cytoplasmic abundance in lung tissue regenerating after injury. In this study, we investigated whether mitogen-activated protein kinase （MAPK）-activated protein kinase 2 （MK2） and HuR participate in the tumor necrosis factor （TNF）-induced expression of interleukin-6 （IL-6）. Methods Human pulmonary microvascular endothelial cells were treated with TNF following short interfering RNAmediated knockdown of MK2 or HuR. Cell supernatants were collected to detect the mRNA and protein expression of IL-6 at different time points, The expression and half-life of IL-6 mRNA were then determined in cells that had been treated with actinomycin D. Finally, after knockdown of MK2, the cytoplasmic expression of HuR protein was analyzed using Western blotting. Results MK2 or HuR knockdown decreased both the mRNA and protein expression of IL-6 in TNF-stimulated cells. In MK2 knockdown cells, the half-life of IL-6 mRNA was reduced to 36 minutes, compared with 67 minutes in the control group. In HuR knockdown cells, the half-life of IL-6 mRNA decreased from 62 minutes to 24 minutes. Further analysis revealed that knockdown of MK2 resulted in reduced HuR protein expression in the cytoplasm. Conclusions MK2 regulates the TNF-induced expression of IL-6 by influencing the cytoplasmic levels of HuR.

Mechanisms mediating the effects of alcohol and HIV anti-retroviral agents on mTORC1,mTORC2 and protein synthesis in myocytes

Alcoholism and acquired immune deficiency syndrome are associated with severe muscle wasting.This impairment in nitrogen balance arises from increased protein degradation and a decreased rate of protein synthesis.The regulation of protein synthesis is a complex process involving alterations in the phosphorylation state and protein-protein interaction of various components of the translation machinery and mammalian target of rapamycin(mTOR) complexes.This review describes mechanisms that regulate protein synthesis in cultured C2C12 myocytes following exposure to either alcohol or human immunodeficiency virus antiretroviral drugs.Particular attention is given to the upstream regulators of mTOR complexes and the downstream targets which play an important role in translation.Gaining a better understanding of these molecular mechanisms could have important implications for preventing changes in lean body mass in patients with catabolic conditions or illnesses.

Association of Common Genetic Variants in Mitogen-activated Protein Kinase Kinase Kinase Kinase 4 with Type 2 Diabetes Mellitus in a Chinese Han Population

Background： A study has identified several novel susceptibility variants of the mitogen-activated protein kinase kinase kinase kinase 4 （MAP4K4） gene for type 2 diabetes mellitus （T2DM） within the German population. Among the variants, five single nucleotide polymorphisms （SNPs） of MAP4K4 （rs1003376, rs1 1674694, rs2236935, rs2236936, and rs6543087） showed significant association with T2DM or diabetes-related quantitative traits. We aimed to evaluate whether common SNPs in the MAP4K4 gene were associated with T2DM in the Chinese population. Methods： Five candidate SNPs were genotyped in 996 patients newly diagnosed with T2DM and in 976 control subjects, using the SNPscanTM method. All subjects were recruited from the Second Affiliated Hospital, Harbin Medical University from October 2010 to September 2013. We evaluated the T2DM risk conferred by individual SNPs and haplotypes using logistic analysis, and the association between the five SNPs and metabolic traits in the subgroups. Results： Of the five variants, SNP rs2236935T/C was significantly associated with T2DM in this study population （odds ratio = 1.293; 95% confidence interval： 1.034-1.619, P= 0.025）. In addition, among the controls, rs1003376 was significantly associated with an increased body mass index （P = 0.045） and homeostatic model assessment-insulin resistance （P = 0.037）. Conclusions： MAP4K4 gene is associated with T2DM in a Chinese Han population, and MAP4K4 gene variants may contribute to the risk toward the development of T2DM.

基于UBA2/PTEN/PI3K/Akt通路探讨蔓荆子黄素对结直肠癌细胞增殖、迁移和侵袭的影响

目的 基于泛素样修饰激活酶2(UBA2)/磷酸酶及张力蛋白同源物(PTEN)/磷脂酰肌醇3-激酶(PI3K)/蛋白激酶B(Akt)通路探究蔓荆子黄素对结直肠癌SW480细胞增殖、迁移和侵袭的影响。方法 取对数生长期的SW480细胞,对照组细胞常规培养,蔓荆子黄素组细胞加入10μmol/L蔓荆子黄素培养,UBA2抑制剂组细胞加入0.5μmol/L UBA2抑制剂培养,蔓荆子黄素+UBA2抑制剂组细胞加入10μmol/L蔓荆子黄素和0.5μmol/L UBA2抑制剂共培养。CCK-8实验检测细胞增殖情况,克隆形成实验观察细胞的单克隆形成能力,划痕实验观察细胞的迁移能力,Transwell实验观察细胞的侵袭能力,Western blot法检测细胞中UBA2/PTEN/PI3K/Akt通路相关蛋白表达情况。结果 CCK-8实验和克隆形成实验显示,UBA2抑制剂组和蔓荆子黄素+UBA2抑制剂组培养72 h后的细胞增殖吸光度OD值明显低于蔓荆子黄素组(P均<0.05),细胞克隆形成数量均明显少于蔓荆子黄素组(P均<0.05),UBA2抑制剂组和蔓荆子黄素+UBA2抑制剂组培养不同时间的细胞增殖吸光度OD值和细胞克隆形成数量比较差异均无统计学意义(P均>0.05)。划痕实验和Transwell实验显示,UBA2抑制剂组和蔓荆子黄素+UBA2抑制剂组划痕间距均明显宽于蔓荆子黄素组(P均<0.05),穿膜细胞数量均明显少于蔓荆子黄素组(P均<0.05),UBA2抑制剂组和蔓荆子黄素+UBA2抑制剂组比较差异均无统计学意义(P均>0.05)。蔓荆子黄素组、UBA2抑制剂组和蔓荆子黄素+UBA2抑制剂组细胞中PTEN蛋白相对表达量均明显高于对照组(P均<0.05),UBA2、p-PI3K、p-Akt蛋白相对表达量均明显低于对照组(P均<0.05);UBA2抑制剂组和蔓荆子黄素+UBA2抑制剂组细胞中PTEN蛋白相对表达量均明显高于蔓荆子黄素组(P均<0.05),UBA2、p-PI3K、p-Akt蛋白相对表达量均明显低于蔓荆子黄素组(P均<0.05),UBA2抑制剂组和蔓荆子黄素+UBA2抑制剂组UBA2、PTEN、p-PI3K、p-Akt蛋白相对表达量比较差异均无统计学意义(P均>0.05)。结论 蔓荆子黄素可能通过抑制UBA2/PTEN/PI3K/Akt信号通路发挥抗结直肠癌SW480细胞增殖、迁移和侵袭的能力。

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.

Effect of inhibiting tyrosine kinase Src expression on protein phosphatase 2A and tau phosphorylation

The aim of this study is to investigate the effect of tyrosine kinase Src on Tyrosine 307(Y307)phosphor-ylation,protein phosphatase 2A(PP2A)activity,and on tau phosphorylation.Specific Src siRNA was transfected into cultured mouse neuroblastoma N2a cells to inhibit the expression of Src protein,and the phosphorylation levels of PP2A Y307 and tau at different sites,as well as PP2A activity were detected at different time points after siRNA transfection.Twelve hours after siRNA transfec-tion,the protein level of Src was dramatically decreased,with decreased PP2A Y307 phosphorylation.However,the total PP2A protein level was also decreased,together with a decreased PP2A activity.Tau was hyperpho-sphorylated at the Ser198/199/202 sites.Multiple factors may be involved in the cellular regulation of PP2A activ-ity.Inhibiting Src expression could induce inactivation of PP2A and tau hyperphosphorylation.

SHP2表达变化对四氯化碳诱导的肝纤维化大鼠肝组织中Akt表达的影响

目的 探讨含SH2结构域的蛋白酪氨酸磷酸酶2(SHP2)过表达及低表达对四氯化碳(CCl4)诱导的肝纤维化大鼠肝组织中蛋白激酶B(Akt)的影响。方法选取160只健康雄性SD大鼠,随机分为对照组、模型组、AdGFP组、Ad-SHP2组和Ad-shRNA/SHP2组,每组32只。采用腹腔注射CCl4法构建大鼠肝纤维化模型,经大鼠尾静脉分别将表达绿色荧光蛋白(GFP)的空病毒Ad-GFP、表达野生型SHP2及GFP的腺病毒Ad-SHP2、表达GFP并携带靶向SHP2的短发夹RNA(shRNA)的腺病毒Ad-shRNA/SHP2注入大鼠体内。各组分别于造模第2、4、6、8周随机选取8只大鼠,留取肝组织标本。采用实时荧光定量PCR法检测各组大鼠肝组织中SHP2、Akt的mRNA表达水平,采用蛋白质印迹法检测各组大鼠肝组织中SHP2、Akt及磷酸化Akt(p-Akt)的蛋白表达水平,采用H-E染色法观察各组大鼠肝组织的病理变化,采用Masson三色染色法观察各组大鼠肝组织的胶原沉积情况。结果 靶向SHP2的shRNA及外源性野生型SHP2基因成功导入肝纤维化大鼠体内,并使大鼠肝组织中SHP2呈低表达或过表达。与模型组及Ad-GFP组比较,Ad-SHP2组大鼠的肝纤维化程度加重,而Ad-shRNA/SHP2组大鼠的肝纤维化程度则减轻。在同一造模时间点(第2、4、6、8周)对各组大鼠肝组织中Akt的m RNA和蛋白表达水平,以及p-Akt蛋白表达水平进行比较,结果显示Ad-GFP组、Ad-SHP2组、Ad-shRNA/SHP2组及模型组均显著高于对照组(P均<0.05),而各时间点的Ad-GFP组、Ad-SHP2组、Ad-shRNA/SHP2组及模型组的Akt表达水平差异均无统计学意义(P均>0.05);与模型组及Ad-GFP组大鼠肝组织中p-Akt表达水平相比较,AdshRNA/SHP2组在各时间点均显著降低(P均<0.05),Ad-SHP2组在各时间点均显著升高(P均<0.05),模型组与Ad-GFP组的p-Akt表达水平差异均无统计学意义(P均>0.05)。结论 在CCl4诱导的大鼠肝纤维化病程中,肝组织中SHP2过表达可通过促进Akt磷酸化增强Akt的活性,而肝组织中SHP2低表达则可通过抑制Akt磷酸化减弱Akt的活性。