Protective effect of apoptosis signal-regulating kinase1 inhibitor against mice liver injury

Objective:To explore the protective effect and its molecular mechanism of apoptosis signalregulating kinase 1(ASK1) inhibitor(GS-459679) on acetaminophen-induced liver injury in mice.Methods:The model of liver injury was established by administration of acetaminophen(APAP)(300 mg/kg,i.p.) on C57BL/6 mice.Forty-eight male C57BL/6 mice were randomly divided into four groups,consisting of control group,GS group(GS-459679,30 mg/kg,i.p.),APAPinduced group,and GS combined with APAP-induced group.For GS combined with APAPinduced group,mice were treated with GS 30 min prior to administration of APAP.After mice were euthanized at 6 h or 12 h.respectively,serum levels of alanine aminotransferase(ALT) and aspartate aminotransferase(AST) were analyzed,and mRNA levels of TNF- α,IL-6 and IL-1βwere tested.The activity of glutathione(GSH),oxidized GSH(GSSG) and malondialdehyde were quantified.In addition,ASK1,P-ASK1,JNK and P-JNK protein levels were tested in all groups.Results:The ASK1 and P-ASK1 levels were up-regulated in APAP-induced group.Compared to the control group,serum levels of ALT and AST.and mRNA levels of TNF- a,IL-6 and IL-1(3were increased in APAP-induced group.Meanwhile,the levels of MAD and GSSG.and the ratio of GSSG/GSH were higher and the JNK was activatedin APAP-induced group compared with that in control group.However,compared to APAP-induced group,GS combined with APAP-induced group displayed a decrease of protein expression levels of ASK 1,P-ASKI and P-JNK,a reduction of serum levels of ALT and AST,a decrease in TNF- a.IL-6 and IL-1(3 mRNA levels,and a low ration of GSSG/GSH.Conclusions:GS-459679 treatment effectively down-regulates ASK1 and P-ASK 1 expression.Addition of GS-459679 decreases the generation of liver metabolites and inflammatory factors,reduces oxidative stress reaction,inhibits JNK activation,and then protects the responsiveness to APAP-induced liver injury.

XAF1 mediates apoptosis through an extracellular signal-regulated kinase pathway in colon cancer

Background:XIAP-associated factor 1(XAF1)negatively regulates the function of the X-linked inhibitor of apoptosis protein(XIAP),a member of the IAP family that exerts antiapoptotic effects.The extracellular signal-regulated kinase(ERK)pathway is thought to increase cell proliferation and to protect cells from apoptosis.The aim of the study was to investigate the correlation between the ERK1/2 signaling pathway and XAF1 in colon cancer.Methods:Four human colon cancer cell lines,HCT1116 and Lovo(wildtype p53),DLD1 and SW1116(mutant p53),were used.Lovo stable transfectants with XAF1 sense and antisense were established.The effects of dominant-negative MEK1(DN-MEK1)and MEK-specific inhibitor U0126 on the ERK signaling pathway and expression of XAF1 and XIAP proteins were determined.The transcription activity of core XAF1 promoter was assessed by dual luciferase reporter assay.Cell proliferation was measured by MTT assay.Apoptosis was determined by Hoechst 33258 staining.Results:U0126 increased the expression of XAF1 in a time-and dose-dependent manner.A similar result was obtained in cells transfected with DN-MEK1 treatment.Conversely,the expression of XIAP was down-regulated.Activity of the putative promoter of the XAF1 gene was significantly increased by U0126 treatment and DN-MEK1 transient transfection.rhEGF-stimulated phosphorylation of ERK appeared to have little or no effect on XAF1 expression.Overexpression of XAF1 was more sensitive to U0126-induced apoptosis,whereas down-regulation of XAF1 by antisense reversed U0126-induced inhibition of cell proliferation.Conclusions:XAF1 expression was up-regulated by inhibition of the ERK1/2 pathway through transcriptional regulation,which required de novo protein synthesis.The results suggest that XAF1 mediates apoptosis induced by the ERK1/2 pathway in colon cancer.

Dual targeting of Polo-like kinase 1 and baculoviral inhibitor of apoptosis repeat-containing 5 in TP53-mutated hepatocellular carcinoma

BACKGROUND Hepatocellular carcinoma(HCC),often diagnosed at advanced stages without curative therapies,is the fifth most common malignant cancer and the second leading cause of cancer-related mortality.Polo-like kinase 1(PLK1)is activated in the late G2 phase of the cell cycle and is required for entry to mitosis.Interestingly,PLK1 is overexpressed in many HCC patients and is highly associated with poor clinical outcome.Baculoviral inhibitor of apoptosis repeatcontaining 5(BIRC5)is also highly overexpressed in HCC and plays key roles in this malignancy.AIM To determine the expression patterns of PLK1 and BIRC5,as well as their correlation with p53 mutation status and patient clinical outcome.METHODS The expression patterns of PLK1 and BIRC5,and their correlation with p53 mutation status or patient clinical outcome were analyzed using a TCGA HCC dataset.Cell viability,cell apoptosis,and cell cycle arrest assays were conducted to investigate the efficacy of the PLK1 inhibitors volasertib and GSK461364 and the BIRC5 inhibitor YM155,alone or in combination.The in vivo efficacy of volasertib and YM155,alone or in combination,was assessed in p53-mutated Huh7-derived xenograft models in immune-deficient NSIG mice.RESULTS Our bioinformatics analysis using a TCGA HCC dataset revealed that PLK1 and BIRC5 were overexpressed in the same patient subset and their expression was highly correlated.The overexpression of both PLK1 and BIRC5 was more frequently detected in HCC with p53 mutations.High PLK1 or BIRC5 expression significantly correlated with poor clinical outcome.PLK1 inhibitors(volasertib and GSK461364)or a BIRC5 inhibitor(YM155)selectively targeted Huh7 cells with mutated p53,but not HepG2 cells with wild-type p53.The combination treatment of volasertib and YM155 synergistically inhibited the viability of Huh7 cells via apoptotic pathway.The efficacy of volasertib and YM155,alone or in combination,was validated in vivo in a Huh7-derived xenograft model.CONCLUSION PLK1 and BIRC5 are highly co-expressed in p53-mutated HCC and inhibition of both PLK1 and BIRC5 synergistically compromises the viability of p53-mutated HCC cells in vitro and in vivo.

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.

Regulation of extracellular signal-regulated kinase 1/2 influences hippocampal neuronal survival in a rat model of diabetic cerebral ischemia

Activation of extracellular signal-regulated kinase 1/2 has been demonstrated in acute brain ischemia. We hypothesized that activated extracellular signal-regulated kinase 1/2 can protect hippocampal neurons from injury in a diabetic model after cerebral ischemia/reperfusion. In this study, transient whole-brain ischemia was induced by four-vessel occlusion in normal and diabetic rats, and extracellular signal-regulated kinase 1/2 inhibitor （U0126） was administered into diabetic rats 30 minutes before ischemia as a pretreatment. Results showed that the number of surviving neurons in the hippocampal CA1 region was reduced, extracellular signal-regulated kinase 1/2 phosphorylation and KuT0 activity were decreased, and pro-apoptotic Bax expression was upregulated after intervention using U0126. These findings demonstrate that inhibition of extracellular signal-regulated kinase 1/2 activity aggravated neuronal loss in the hippocampus in a diabetic rat after cerebral ischemia/reperfusion, further decreased DNA repairing ability and ac- celerated apoptosis in hippocampal neurons. Extracellular signal-regulated kinase 1/2 activation plays a neuroprotective role in hippocampal neurons in a diabetic rat after cerebral ischemia/ reperfusion.

Serine-threonine protein kinase activation may be an effective target for reducing neuronal apoptosis after spinal cord injury

The signaling mechanisms underlying ischemia-induced nerve cell apoptosis are poorly understood. We investigated the effects of apoptosis-related signal transduction pathways following ischemic spinal cord injury, including extracellular signal-regulated kinase（ERK）, serine-threonine protein kinase（Akt） and c-Jun N-terminal kinase（JNK） signaling pathways. We established a rat model of acute spinal cord injury by inserting a catheter balloon in the left subclavian artery for 25 minutes. Rat models exhibited notable hindlimb dysfunction. Apoptotic cells were abundant in the anterior horn and central canal of the spinal cord. The number of apoptotic neurons was highest 48 hours post injury. The expression of phosphorylated Akt（pAkt） and phosphorylated ERK（p-ERK） increased immediately after reperfusion, peaked at 4 hours（p-Akt） or 2 hours（p-ERK）, decreased at 12 hours, and then increased at 24 hours. Phosphorylated JNK expression reduced after reperfusion, increased at 12 hours to near normal levels, and then showed a downward trend at 24 hours. Pearson linear correlation analysis also demonstrated that the number of apoptotic cells negatively correlated with p-Akt expression. These findings suggest that activation of Akt may be a key contributing factor in the delay of neuronal apoptosis after spinal cord ischemia, particularly at the stage of reperfusion, and thus may be a target for neuronal protection and reduction of neuronal apoptosis after spinal cord injury.

Dexamethasone suppresses DU145 cell proliferation and cell cycle through inhibition of the extracellular signal-regulated kinase 1 /2 pathway and cyclin D1 expression

Aim： To determine the mechanisms of glucocorticoids in inhibiting advanced prostate cancer growth. Methods： The cell proliferation and cell cycle of prostate cancer DU145 cells following dexamethasone treatment were determined by proliferation assay and fluorescence-activated cell sorter. Western blot analysis was carried out to evaluate the effects of dexamethasone on phosphorylation of extracellular signal-regulated kinase （ERK）1/2 and expression of cyclin D1 in DU145 cells with or without glucocorticoid receptor （GR） antagonist RU486. Reverse transcription- polymerase chain reaction verified the expression of GR mRNA in DU145 cells. Results： Dexamethasone significantly inhibited DU 145 cell proliferation at the G0/G1 phase. Westem blot analysis showed a dramatic reduction of ERK1/2 activity and cyclin D1 expression in dexamethasone-treated cells. The decreased phosphorylation of ERK1/2 in dexamethasone-treated cells was attenuated by GR blockade. Additionally, the effects of dexamethasone in inhibiting cyclin D1 expression were altered by GR blockade. Conclusion： Dexamethasone suppresses DU145 cell proliferation and cell cycle, and the underlying mechanisms are through the inhibition of phosphorylation of ERK1/2 and cyclin D1 expression. The inhibition of ERK1/2 phosphorylation and cyclin D1 expression is attenuated by GR blockade, suggesting that GR regulates ERK1/2 and cyclin D1 pathways. These observations suggest that dexamethasone has a potential clinical application in prostate cancer therapy.

Downregulation of Aquaporin 4 Expression through Extracellular Signal-regulated Kinases1/2 Activation in Cultured Astrocytes Following Scratch-injury

Objective 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. Methods 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. Results 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. Conclusion 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.

Adenosine monophosphate-activated protein kinase activation enhances embryonic neural stem cell apoptosis in a mouse model of amyotrophic lateral sclerosis

Alterations in embryonic neural stem cells play crucial roles in the pathogenesis of amyotrophic lateral sclerosis. We hypothesized that embryonic neural stem cells from SOD1G93A individuals might be more susceptible to oxidative injury, resulting in a propensity for neurodegeneration at later stages. In this study, embryonic neural stem cells obtained from human superoxide dis- mutase 1 mutant （SOD1G93A） and wild-type （SOD1wv） mouse models were exposed to H202. We assayed cell viability with mitochondrial succinic dehydrogenase colorimetric reagent, and measured cell apoptosis by flow cytometry. Moreover, we evaluated the expression of the adenos- ine monophosphate-activated protein kinase （AMPK） ct-subunit, paired box 3 （Pax3） protein, and p53 in western blot analyses. Compared with SOD1wr cells, SOD1~93A embryonic neural stem cells were more likely to undergo H202-induced apoptosis. Phosphorylation of AMPKct in SOD1G93A cells was higher than that in SOD1wr cells. Pax3 expression was inversely correlated with the phosphorylation levels of AMPKct. p53 protein levels were also correlated with AMPKct phosphorylation levels. Compound C, an inhibitor of AMPKa, attenuated the effects of H20~. These results suggest that embryonic neural stem cells from SOD1C93A mice are more susceptible to apoptosis in the presence of oxidative stress compared with those from wild-type controls, and the effects are mainly mediated by Pax3 and p53 in the AMPKa pathway.

Time-dependent effects of electroacupuncture at the Ren channel on extracellular signal-regulated kinases 1/2 expression in focal cerebral ischemia rats

BACKGROUND： The onset of focal cerebral ischemia activates extracellular signal-regulated kinases 1 and 2, regulates cell cycle, promotes cell proliferation and differentiation, and affects the normal stage and function of brain cells. OBJECTIVE： To observe the effects of electroacupuncture at the Ren channel on extracellular signal-regulated kinases 1/2 expression in the lateral cerebral ventricle wall of rats with focal cerebral ischemia. The effects were analyzed at different time points after intervention. DESIGN： Randomized controlled study. SETTING： Department of Anatomy, Sun Yat-Sen University. MATERIALS： A total of 60 healthy adult male Wistar rats weighing （250±10） g were provided by the Experimental Animal Center, Medical College of Sun Yat-Sen University. The animal experiment was conducted with confirmed consent by the local ethics committee. The GB6805-Ⅱ electric acupuncture apparatus was provided by Shanghai Medical Equipment High-techno Company. METHODS： The experiment was performed at the Laboratory of Anatomy, Sun Yat-Sen University, from February to July 2007. All experimental animals were randomly divided into the following groups： normal group （n = 6）, sham operation group （n = 18）, model group （n = 18）, and electroacupuncture group （n = 18）. Middle cerebral artery occlusion （MCAO） was performed in the model group and electroacupuncture group. Zea Longa＇s grading standard was used to assess neurological impairment after reperfusion; animals whose grades were between l and 4 were included in this study. The normal control group was not exposed to MCAO. In sham operation animals, the right common carotid artery （CCA） was isolated, and the external carotid artery （ECA） was damaged, but no embolism was induced. The electroacupuncture group was given acupuncture on the second day after surgery. The acupoint locations were chosen according to Experimental Acupuncture （People＇s Publishing House; 1997; First Edition）. The Chengjiang, Qihai, and Guanyuan acupoints were labeled and connected to a G6805 electroacupuncture apparatus with sparse-dense waves （sparse waves were 30 Hz, dense waves were 100 Hz）, with a frequency of 6-15 V. The duration was 20 minutes. Two days after surgery, the model and sham operation groups were placed with their backs on the operating table, but they received no acupuncture. However, the normal group received acupuncture. The experimental animals under anesthesia were sacrificed on days 7, 14, and 28 post-surgery. Western blot analysis was used to measure expression of extracellular signal-regulated kinases 1/2 in the inferior region of the lateral cerebral ventricle wall. Expression was measured in the normal group at time points corresponding to the sham operation group. MAIN OUTCOME MEASURES： Expression of extracellular signal-regulated kinases 1/2 in the inferior region of the lateral cerebral ventricle wall at different time points after intervention. RESULTS： All 60 rats were included in the final analysis, without any loss. Seven days after MCAO, there was no significant difference in extracellular signal-regulated kinases 1/2 expression in the electroacupuncture group compared to the model group （P 〉 0.05）. However, extracellular signal-regulated kinases 1/2 expression significantly increased in the model group at 14 and 28 days after treatment （P 〈 0.05）. CONCLUSION： Electroacupuncture at the Ren channel can enhance extracellular signal-regulated kinasesl/2 expression in the inferior region of the lateral cerebral ventricle wall of rats with focal cerebral ischemia. However, this effect is not apparent until 14 days after electroacupuncture intervention.

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.

三氧化二砷对结肠癌SW-480细胞凋亡及polo-like kinase-1基因表达的影响

目的观察三氧化二砷对人结肠癌细胞SW-480并探讨其作用机理。方法采用不同浓度的三氧化二砷作用结肠癌SW-480细胞后,采用MTT法检测细胞的恶性增殖,采用琼脂糖凝胶电泳和流式细胞仪检测凋亡及细胞周期情况,采用定量PCR检测polo-likekinase-1(PLK1)mRNA水平。结果三氧化二砷能抑制结肠癌细胞的恶性增殖,且与浓度相关。三氧化二砷能诱导结肠癌细胞凋亡,且呈浓度依赖性。流式细胞仪检测发现,三氧化二砷将细胞阻滞在G2/M期。三氧化二砷能下调结肠癌PLK1mRNA水平,且呈药物浓度和作用时间依赖性。结论三氧化二砷有效地抑制结肠癌SW-480细胞增殖,其机制可能与其下调PLK1表达,从而诱导凋亡有关。

受体相互作用蛋白激酶1调节癌症进展和免疫反应的研究现状

受体相互作用蛋白激酶1(receptor-interacting protein kinase 1,RIPK1)是一种多结构域丝氨酸/苏氨酸蛋白激酶。它通过磷酸化特定的蛋白质,引起下游的信号转导和生物效应。近年来,随着对RIPK1的深入研究,学者发现其在自身免疫性疾病、神经退行性疾病,以及多种实体瘤和血液肿瘤中具有重要意义。一方面,RIPK1通过激活特定通路如核因子-κB(nuclear factor-κB,NF-κB)和丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)等促进细胞存活及炎症反应。另一方面,RIPK1通过与胱天蛋白酶-8(cysteinyl aspartate specific proteinase-8,caspase-8)作用促进凋亡,或与RIPK3和混合谱系激酶结构域样假激酶(mixed lineage kinase domain-like protein,MLKL)作用促进坏死性凋亡的发生。RIPK1作为上游信号在不同肿瘤患者中表达水平不同。其支架功能和激酶活性可以调节癌症进展,也可以启动机体适应性免疫,抑制肿瘤进展;此外,还能产生免疫抑制性肿瘤微环境而促进肿瘤的发展。其双重作用在调节癌症的发生、发展及机体免疫反应方面都有所展现,可以作为新的治疗靶点控制癌症进展。该文从RIPK1的结构入手,深入探讨其功能,特别是其在调节癌症进展和免疫反应方面的功能,为癌症靶向药物的开发提供新的思路。

EEF1A1对急性心肌梗死模型大鼠心肌细胞凋亡及Notch/AKT转导途径的影响

目的:探讨人类真核翻译延长因子(EEF1A1)对急性心肌梗死(AMI)模型大鼠心肌细胞凋亡及Notch/蛋白激酶B(AKT)转导途径的影响。方法:将30只SD雄性大鼠随机分为假手术组、模型组、干预组,每组10只,模型组、干预组于冠状动脉左前降支结扎建立AMI大鼠模型,对照组仅手术穿线处理不结扎。建模后24 h干预组于心肌梗死区原位注射EEF1A1腺病毒,模型组、对照组注射等量生理盐水。干预72 h后,心脏彩超测定大鼠心功能,采用脱氧核糖核苷酸末端转移酶介导的缺口末端标记(TUNEL)染色法评估心肌细胞凋亡,2,3,5-氯化三苯基四氮唑(TCC)染色法评估心肌梗死面积,采用实时定量聚合酶链式反应(RT-PCR)法测定EEF1A1 mRNA表达量,蛋白免疫印迹法(Western Blot)检测心肌组织EEF1A1蛋白以及Notch/AKT信号通路相关蛋白表达情况。结果:干预前,模型组、干预组左室射血分数(LVEF)明显低于假手术组(P<0.05),而左心室收缩末期内径(LVESD)、左心室舒张末期内径(LVEDD)明显高于假手术组(P<0.05);干预后3 d后,干预组LVEDD、LVESD明显降低,而LVEF明显增加,模型组LVEDD、LVESD明显增加,而LVEF明显降低,差异均有统计学意义(P<0.05)。干预组心肌组织EEF1A1蛋白及mRNA表达水平高于假手术组、模型组(P<0.05),而模型组心肌组织EEF1A1蛋白及mRNA表达水平高于假手术组(P<0.05)。干预组心肌梗死面积小于模型组(P<0.05)。干预组心肌细胞凋亡率明显高于假手术组(P<0.05),明显低于模型组(P<0.05)。干预组Notch1、Hes1、磷酸化AKT(p-AKT)/AKT相关蛋白表达明显高于模型组、假手术组,模型组Notch1、Hes1、p-AKT/AKT相关蛋白表达均明显高于假手术组(P<0.05)。结论:EEF1A1可抑制AMI大鼠心肌细胞损伤、凋亡,缩小心肌梗死面积,改善心脏功能,其作用机制可能与上调Notch/AKT转导途径有关。

PIM1基因对急性髓系白血病U937细胞增殖、凋亡及JAK2/STAT3信号通路的影响

目的:探讨PIM1基因对急性髓系白血病(AML)U937细胞增殖、凋亡的影响,以及对JAK2/STAT3通路的调控作用。方法:收集初诊成人AML患者和单纯缺铁性贫血患者的骨髓单个核细胞,荧光定量PCR检测PIM1 mRNA表达。将AML细胞系U937细胞分为:U937组(U937细胞正常培养)、Si-PIM1组(U937细胞转染含PIM1 mRNA的低表达腺病毒载体)、Si-NC组(U937细胞转染不含PIM1 mRNA的低表达腺病毒载体)、CoA1组(U937细胞中加入浓度为20μmol/L的JAK2激活剂CoA1)、Si-PIM1+CoA1组(U937细胞转染含PIM1 mRNA低表达的腺病毒载体并加入浓度为20μmol/L的CoA1)。培养24 h。荧光定量PCR和蛋白印迹法检测U937细胞PIM1 mRNA和蛋白、JAK2/STAT3通路、细胞周期、凋亡相关蛋白表达;噻唑蓝法检测细胞增殖活性;流式细胞术检测细胞周期变化及凋亡率。结果:AML患者骨髓单个核细胞中PIM1 mRNA表达水平高于单纯缺铁性贫血患者(P<0.05)。与U937组相比,Si-PIM1组细胞PIM1 mRNA和蛋白、p-JAK2/JAK2、p-STAT3/STAT3、Cyclin D1、CDK2蛋白、细胞增殖活性、S期比例、G2/M期比例降低(均P<0.05),p27、Caspase-3蛋白、G0/G1期、凋亡率升高(均P<0.05),而CoA1组上述指标的变化情况与Si-PIM1组正好相反,CoA1可逆转Si-PIM1对U937细胞的作用效果。U937组、Si-PIM1+CoA1组、Si-NC组U937细胞上述指标差异无统计学意义(P>0.05)。结论:敲低PIM1基因表达可抑制U937细胞增殖、促进凋亡,缓解ALM进程,且上述作用可能与抑制JAK2/STAT3通路活化有关。

RNAi沉默Polo-like kinase-1基因表达对胰腺癌细胞增殖的影响

目的:探讨polo-like kinase-1(PLK1)基因在胰腺癌细胞中的作用.方法:采用PLK1小干扰核糖核酸分子(small interfering RNA,siRNA)转染人胰腺癌Mi- aPaCa-2细胞后,分别采用实时定量PCR和Western blot检测PLK1基因mRNA和蛋白表达水平,观察PLK1 siRNA转染对胰腺癌细胞体内外增殖的影响.于转染不同时间后收集细胞,分别采用琼脂糖凝胶电泳和TUNEL方法检测胰腺癌细胞凋亡情况.结果:胰腺癌MiaPaCa-2细胞经siRNA转染处理后,PLK1 mRNA和蛋白表达水平明显下降(P<0.05).PLK1基因siRNA可明显抑制癌细胞体外生长(P<0.05)和体内裸鼠模型增殖(P<0.05).细胞凋亡检测发现,DNA电泳出现明显的梯度图谱,且与浓度相关(r=0.836,P<0.05).TUNEL结果显示,转染组癌细胞凋亡指数明显增加,且呈时间和浓度依赖性(r= 0.875,P<0.05).结论:PLK1 siRNA转染可明显抑制胰腺癌细胞增殖,其机制可能与诱导细胞凋亡有关.

Regulating effect of glycyrrhetinic acid on bronchial asthma smooth muscle proliferation and apoptosis as well as inflammatory factor expression through ERK1/2 signaling pathway

Objective: To study the influence of glycyrrhetinic acid(GA) on bronchial asthma(BA)smooth muscle proliferation and apoptosis as well as inflammatory factor expression and its molecular mechanism.Methods: Male SD guinea pigs were selected and made into asthma models, bronchial asthma smooth muscle cells were cultured and divided into BA group, GA group and GA + LM group that were treated with serum-free RPMI1640 culture medium, serumfree RPMI1640 culture medium containing 50 ng/mL glycyrrhetinic acid, serum-free RPMI1640 culture medium containing 50 ng/mL glycyrrhetinic acid and 100 ng/mL LM22B-10 respectively; normal guinea pigs were collected and bronchial smooth muscle cells were cultured as control group. The cell proliferation activity as well as the expression of proliferation and apoptosis genes, inflammatory factors and p-ERK1/2 was determined.Results: Proliferation activity value and m RNA expression of Bcl-2, TNF-α, IL-4, IL-6,YKL-40, protein expression of p-ERK1/2 of airway smooth muscle cell in BA group were significantly higher than those of control group while m RNA expression levels of Bax,caspase-9 as well as caspase-3 were significantly lower than that of control group(P < 0.05); proliferation activity value and m RNA expression of Bcl-2, TNF-α, IL-4, IL-6, YKL-40, protein expression of p-ERK1/2 of airway smooth muscle cell in GA group were significantly lower than those of BA group(P < 0.05) while the m RNA expression levels of Bax, caspase-9 as well as caspase-3 were significantly higher than those of BA group(P < 0.05); proliferation activity value and m RNA expression of Bcl-2, TNF-α, IL-4, IL-6, YKL-40 of airway smooth muscle cell in GA + LM group were significantly higher than those of GA group(P < 0.05) while m RNA expression levels of Bax, caspase-9 as well as caspase-3 were significantly lower that of GA group(P < 0.05).Conclusion: GA can inhibit the proliferation of bronchial smooth muscle cells and reduce the expression of inflammatory factors by inhibiting the phosphorylation of ERK1/2.

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.

Effects of Oxymatrine on the Apoptosis of Human Esophageal Carcinoma Eca109 Cell Line and Its Mechanism

The effects of Oxymatrine （Oxy） on the proliferation and apoptosis of human esophageal carcinoma Ecal09 cell line and the mechanism were investigated. The human esophageal carcinoma Eca 109 celis were cultured in vitro. The Oxy-induced apoptosis of Eca 109 cells was assayed by using flow cytometry. The expressions of p-ERKII2, Cyclin D1, p21^waf/cipl, Bax and Bcl-2 were detected by Western blot. Flow cytometry revealed that Oxy could induce the apoptosis of Eca l09 cells. Western blot showed that Oxy of different concentrations suppressed the expressions of p-ERK1/2, Cyclin D1 and Bcl-2, but up-regulated the expression of p21waf/cip1 and Bax, and the ratio of Bax/Bcl-2 was increased. It was suggested the Oxy could induce the apoptosis of Eca l09 cells, which might be related to the upregulation of p21waf/cip1 and the downregulation of p-ERK1/2, Cyclin D1 and p21^waf/cip1. The possible pathway may be related to Bcl-2/Bax.

Activation of extracellular signal-related kinases 1 and 2 in Sertoli cells in experimentally cryptorchid rhesus monkeys

Aim： To assess the spatiotemporal changes in the expression of extracellular signal-regulated kinases 1 and 2 （ERK1/ 2）, c-Jun N-terminal kinases （JNK） and p38 mitogen-activated protein kinases （MAPK） in response to heat stress in the cryptorchid testis, and to investigate a possible relation to Sertoli cell dedifferentiation. Methods： Immunohistochemistry and western blot were used to examine the expression and activation of ERK1/2, p38 and JNK in the cryptorchid testis at various stages after experimental cryptorchidism. Results： The abdominal temperature did not obviously change the total ERK1/2 expression but significantly activated phospho-ERK1/2 in the Sertoli cells of the cryptorchid testis. Heat stress increased total JNK expression in the Sertoli cells of the cryptorchid testis but did not activate phospho-JNK. Neither total p38 nor phospho-p38 was induced by heat stress in the Sertoli cells of the cryptorchid testis. Changes in the spatiotemporal expression of cytokeratin 18 （CK18）, a marker of immature or undifferentiated Sertoli cells, were induced in the cryptorchid testis in a pattern similar to the activation of ERK1/2. Condusion： The activation of ERK1/2 in the testis may be related to dedifferentiation of Sertoli cells under heat stress induced by experimental cryptorchidism.