心肌特异性丝裂原活化蛋白激酶激活的蛋白激酶2基因敲除对小鼠心肌缺血/再灌注损伤的影响及其机制

目的研究心肌特异性丝裂原活化蛋白激酶激活的蛋白激酶2(MK2)基因敲除对小鼠心肌缺血/再灌注(I/R)损伤的影响及其机制。方法将野生型C57BL/6J小鼠随机分为MK2^(+/+)组、MK2^(+/+)+I/R组,心肌特异性MK 2基因敲除的C57BL/6J小鼠随机分为MK2^(-/-)组、MK2^(-/-)+I/R组,每组12只。采用左冠状动脉前降支夹闭的方法建立小鼠心肌I/R损伤模型。比较各组小鼠心肌中MK2、磷酸化MK2(p-MK2)蛋白质相对表达量,心功能超声指标[左心室射血分数(LVEF)、左心室短轴缩短分数(LVFS)),血清心肌损伤标志物[心肌肌钙蛋白I(cTnI)、磷酸肌酸激酶同工酶(CK-MB)水平],心肌组织结构、心肌梗死面积[梗死区域(IA)面积/左心室(LV)面积],心肌细胞凋亡情况[心肌细胞凋亡率、裂解型含半胱氨酸的天冬氨酸蛋白水解酶-3(cleaved caspase-3)相对表达量],心肌组织炎症反应指标[NF-κB相对表达量及TNF-α、细胞间黏附分子-1(ICAM-1)含量]和氧化应激反应指标[活性氧(ROS)、超氧化物歧化酶(SOD)、丙二醛(MDA)含量]。结果MK2^(+/+)组与MK2^(+/+)+I/R组间小鼠心肌中MK2蛋白质相对表达量的差异无统计学意义(P>0.05),MK2^(+/+)+I/R组小鼠心肌中p-MK2蛋白质相对表达量显著高于MK2^(+/+)组(P<0.05),MK2^(-/-)组、MK2^(-/-)+I/R组小鼠心肌中均不表达MK2、p-MK2。与MK2^(+/+)组比较,MK2^(+/+)+I/R组小鼠的LVEF、LVFS均显著降低(P值均<0.05),血清cTnI、CK-MB水平均显著增高(P值均<0.05);与MK2^(+/+)+I/R组比较,MK2^(-/-)+I/R组小鼠的LVEF、LVFS均显著增高(P值均<0.05),血清cTnI、CK-MB水平均显著降低(P值均<0.05)。MK2^(+/+)组和MK2^(-/-)组小鼠心肌纤维排列整齐,细胞形态正常;MK2^(+/+)+I/R组和MK2^(-/-)+I/R组小鼠均有明显的心肌纤维断裂、细胞肿胀且排列混乱,但MK2^(-/-)+I/R组小鼠的病理改变程度较MK2^(+/+)+I/R组轻。MK2^(+/+)组及MK2^(-/-)组小鼠均无心肌梗死灶,MK2^(-/-)+I/R组小鼠的IA/LV值显著低于MK2^(+/+)+I/R组(P<0.05)。与MK2^(+/+)组比较,MK2^(+/+)+I/R组小鼠的心肌细胞凋亡率,心肌中leaved caspase-3、NF-κB蛋白质相对表达量及TNF-α、ICAM-1含量,以及心肌中ROS、MDA含量均显著增高(P值均<0.05),SOD含量显著降低(P<0.05);与MK2^(+/+)+I/R组小鼠比较,MK2^(-/-)+I/R组小鼠的心肌细胞凋亡率,心肌中cleaved caspase-3、NF-κB相对表达量及TNF-α、ICAM-1含量,以及心肌中ROS、MDA含量均显著降低(P值均<0.05),SOD含量显著增高(P<0.05)。结论MK2参与心肌I/R损伤的发生,敲除MK 2基因可显著减轻心肌I/R损伤,并减少细胞凋亡,减轻炎症反应和氧化应激反应。

丝裂原活化蛋白激酶激活的蛋白激酶2在心血管系统中的作用

心血管疾病的发生发展与慢性炎症有关。p38丝裂原活化蛋白激酶(MAPK)介导的信号通路在心血管细胞炎症、增殖、分化、迁移和代谢中起着重要作用。抑制p38MAPK可有效抑制炎症介质的表达,由于p38抑制剂在安全性方面不可接受,故研究其下游底物是很有必要的。丝裂原活化蛋白激酶激活的蛋白激酶2(MK2)是p38MAPK重要的下游底物且参与了心血管疾病的发生发展。因此抑制MK2的活性在心血管疾病的治疗及预防中具有重大的临床意义。文章主要对MK2的结构功能和在心血管疾病中的作用展开综述。

丝裂原活化蛋白激酶激活的蛋白激酶2的研究进展

丝裂原活化蛋白激酶激活的蛋白激酶2（mitogenactivated protein kinase activated protein kinase2，MK2）属于丝氨酸．苏氨酸蛋白激酶家族，是p38的底物之一。MK2参与体内许多生理功能的调控，包括应激与炎性反应、细胞迁移、肌动蛋白重构等，其对炎性因子的调节作用格外受到重视。研究表明，MK2参与了动脉粥样硬化、高血压、阿尔茨海默病、银屑病、关节炎和急性胰腺炎等疾病的炎性反应过程。因此，对MK2的研究将为上述疾病的防治提供新的方向。

MK2基因在高血压小鼠左心室重塑中的作用及机制研究

目的:研究丝裂原活化蛋白激酶激活的蛋白激酶2(MK2)基因在高血压小鼠左心室重塑中的作用及机制。方法:野生型C57BL/6J小鼠随机分为MK2^(+/+)组、MK2^(+/+)AAC组,MK2基因敲除C57BL/6J小鼠随机分为MK2^(-/-)组、MK2^(-/-)AAC组,采用腹主动脉缩窄术(AAC)建立高血压左心室重塑模型小鼠。检测各组小鼠的收缩压(SBP)、心脏超声指标舒张末期左室前壁厚度(LVAWd)、收缩末期左室前壁厚度(LVAWs)、舒张末期左室后壁厚度(LVPWd)、收缩末期左室后壁厚度(LVPWs)、心肌厚度、心脏/体质量(HW/BW)、心肌HE染色、Masson染色及心肌胶原容积分数(CVF)、血清中脑型脑钠肽(BNP)、血管紧张素Ⅱ(AngⅡ)、醛固酮(ALD)含量、心肌中Ⅰ型胶原(Col-Ⅰ)、Col-Ⅲ、α-平滑肌肌动蛋白(α-SMA)的mRNA表达水平、MK2、NF-κB、Cleaved caspase-3蛋白表达水平、活性氧簇(ROS)、TNF-α、IL-6、总抗氧化力(T-AOC)含量。结果:与MK2^(+/+)组比较,MK2^(+/+)AAC组小鼠的SBP、LVAWd、LVAWs、LVPWd、LVPWs、心肌厚度、HW/BW、CVF水平及心肌中MK2、NF-κB、Cleaved caspase-3蛋白表达水平、Col-Ⅰ、Col-Ⅲ、α-SMA mRNA表达水平、TNF-α、IL-6、ROS含量明显增加,心肌中T-AOC含量明显降低(P<0.05);MK2^(-/-)组各项指标差异均无统计学意义(P>0.05)。与MK2^(+/+)AAC组比较,MK2^(-/-)AAC组小鼠SBP水平无明显变化(P>0.05),LVAWd、LVAWs、LVPWd、LVPWs、心肌厚度、HW/BW、CVF水平及心肌中MK2、NF-κB、Cleaved caspase-3蛋白表达水平、Col-Ⅰ、Col-Ⅲ、α-SMA mRNA表达水平、TNF-α、IL-6、ROS含量明显降低,心肌中T-AOC含量明显增加(P<0.05)。结论:MK2基因高表达与高血压小鼠左心室重塑有关,激活MK2下游炎症反应、氧化应激反应、细胞凋亡是相关的分子机制。

板蓝根抗内毒素机制研究

目的 :探讨板蓝根抗内毒素作用机制。方法 :将具有抗内毒素作用的板蓝根氯仿提取部位 (F0 2 )及该部位中的F0 2 2 组份配制成 1%水溶液 (样品液 )。用电子显微镜观察经样品液作用前后内毒素结构形态的变化 ;用显色基质法检测样品液对内毒素的破坏作用 ;用样品对脂多糖致鼠巨噬细胞分泌炎性因子的抑制作用、对脂多糖刺激鼠组织moesimRNA分子表达影响及对脂多糖诱导鼠体内蛋白激酶MAPKP38、TNFα、IL 6和NO的抑制作用等探讨板蓝根抗内毒素的分子机制。结果 :经板蓝根样品液作用后 ,长链状且相互交叉成网状的内毒素呈不规则的短片状或颗粒状 ;0 5ml1%F0 2 液可使 2 0EU内毒素降解为 0 0 2EU ,破坏率为 99% ;1%F0 2 液和 1%F0 2 2液 2 0ng/ml对浓度为 5 0和 10 0ng/ml的脂多糖刺激巨噬细胞分泌TNFα、IL 6的抑制率分别为 84 4 % ,4 9 0 % ,77 6 % ,4 2 4 %和 78 6 % ,4 1 7% ,85 9% ,39 6 % ;1%F0 2 2 液对脂多糖刺激鼠肝、肾、脾组织moesimRNA分子表达的抑制率分别为 93 5 %、88 6 %和 87 8% ,平均抑制率为 90 1% ;1%F0 2 2 液对脂多糖刺激鼠体内蛋白激酶MAPKP38、TNFα、IL 6和NO的抑制率分别为 93 2 % ,96 6 % ,95 8%和 93 0 %。结论 :板蓝根氯仿提取部位 (F0 2 )及其F0 2

MK2抑制剂PF-3644022对视网膜分支静脉阻塞模型大鼠的治疗作用

目的探讨MK2抑制剂PF-3644022对视网膜分支静脉阻塞(BRVO)模型大鼠的治疗作用。方法通过激光光凝建立BRVO模型大鼠,将BRVO模型大鼠随机分为5组(n=12)对照组、模型组、低剂量组、中剂量组和高剂量组。低、中和高剂量组大鼠分别按1 mg·kg^(-1)、5 mg·kg^(-1)、10 mg·kg^(-1)给予2 mL丝裂原活化蛋白激酶激活的蛋白激酶2(MK2)抑制剂PF-3644022灌胃,对照组和模型组大鼠给予2 mL蒸馏水或生理盐水灌胃,共治疗21 d。分别在治疗后1 d、7 d和14 d进行眼底照相、光学相干断层扫描(OCT)和荧光素眼底血管造影(FFA)检查,利用苏木精-伊红(HE)染色观察各组大鼠视网膜变化,采用免疫荧光染色及Western blot检测各组大鼠视网膜组织中MK2、p-MK2和血管内皮生长因子-α(VEGF-α)的表达。结果HE染色、眼底照相、FFA和OCT检查结果均显示,MK2抑制剂PF-3644022以剂量依赖性方式减轻BRVO模型大鼠视网膜水肿、血管排列紊乱和收缩、视盘陷凹消失等病理现象。Western blot检测结果显示,治疗后1 d,与模型组(1.00±0.05)相比,低剂量组(0.75±0.04)、中剂量组(0.52±0.03)和高剂量组(0.43±0.02)大鼠视网膜组织中VEGF-α蛋白的相对表达水平均显著降低,并呈剂量依赖性降低(均为P<0.05);治疗后21 d,各组大鼠视网膜组织中VEGF-α蛋白的表达均无明显差异(均为P>0.05)。治疗后1 d和21 d,与模型组(1.00±0.05、1.00±0.06)相比,低剂量组(0.51±0.03、0.47±0.02)、中剂量组(0.26±0.01、0.23±0.01)和高剂量组(0.22±0.01、0.21±0.01)大鼠视网膜组织中MK2蛋白的磷酸化水平均显著降低,并呈剂量依赖性降低(均为P<0.05)。结论MK2抑制剂PF-3644022通过减轻视网膜水肿、调节VEGF-α蛋白的表达、抑制MK2活性等作用对BRVO动物模型发挥治疗作用。

脑源性神经营养因子对无血清培养的神经元保护机制的研究

目的探讨在无血清培养条件下脑源性神经营养因子(BDNF)对神经元样细胞存活的影响及其作用机制。方法在无血清条件下培养具有BDNF受体TrkB表达的神经母细胞瘤细胞SY5Y-TrkB,在培养液中单独加入BDNF,或联合加入磷脂酰肌醇3-激酶(PI3K)抑制剂/丝裂原活化蛋白激酶(MAPK)抑制剂进行细胞培养,利用细胞活性测定法(MTS)检测活细胞活性。结果与在10%胎牛血清(FBS)培养液中培养的细胞相比,无血清条件下培养24、48 72 h后,SY5Y-TrkB细胞的存活率分别为51%、38%、25%。若细胞在无血清条件下培养24 h,无处理因素的细胞存活率设定为100%,给予BDNF后的细胞存活率为154%;用10μmol/L PI3K抑制剂LY294002预处理1 h,再给予BDNF后的细胞存活率为100%;而应用80μmol/LMAPK抑制剂PD98059预处理1 h,再给予BDNF后的细胞存活率为158%。结论 BDNF通过PI3K信号通路保护SY5Y-TrkB细胞免受无血清培养引起的细胞死亡。

ERK_(1,2)抑制剂联合5-FU对B16细胞增殖和凋亡的影响

目的:观察ERK1,2抑制剂联合5-FU对B16细胞增殖和凋亡的影响,并探讨作用机制。方法:用MTT法观察ERK1,2抑制剂、5-FU和联合用药对细胞增殖的抑制作用,流式细胞仪检测细胞凋亡率,用RT-PCR观察ERK1,2抑制剂、5-FU和联合用药对bcl-2和caspase-9的表达的影响。结果:ERK1,2抑制剂联合5-FU组在抑制细胞增殖,诱导细胞凋亡,均较对照组、单独用药组作用增强,并且下调bcl-2和上调caspase-9的表达。结论:ERK1,2抑制剂联合5-FU有协同抑制B16细胞增殖,促进凋亡的作用,其机制可能与诱导细胞凋亡,下调bcl-2和上调caspase-9的表达有关。

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.

Epithelial-to-mesenchymal and mesenchymal-to-epithelial transitions in the colon

Epithelial-to-mesenchymal and mesenchymal-to-epi- thelial transitions are well established biological events which have an important role in not just normal tissue and organ development, but in the pathogenesis of diseases. Increasing evidence has established their presence in the human colon during colorectal carcinogenesis and cancer invasion, chronic inflammation-related fibrosis and in the course of mucosal healing. A large body of evidence supports the role for transforming growth factor-13 and its downstream Smad signaling, the phosphatidylinositol 3＇-kinase/Akt/mTOR axis, the Ras-mitogen-activated protein kinase/Snail/Slug and FOXC2 pathway, and Hedgehog signaling and microR- NAs in the development of colorectal cancers via epi- thelial-to-mesenchymal transition. C-met and Frizzled-7, among others, seem to be the principle effectors of mesenchymal-to-epithelial transition, hence have a role not just in mucosal regeneration but in the progression of colonic wall fibrosis. Here we discuss a role for these pathways in the initiation and development of the transition events. A better understanding of their induction and regulation may lead to the identification of pathways and factors that could be potent therapeu- tic targets. The inhibition of epithelial-to-mesenchymal transition using mTOR kinase inhibitors targeting theATP binding pocket and which inhibit both mTORC1 and mTORC2, RNA aptamers or peptide mimetics, such as a Wnt5A-mimetic, may all be useful in both cancer treatment and delaying fibrosis, while the induction of mesenchymal-to-epithelial transition in induced pluripotent stem cells may enhance epithelial healing in the case of severe mucosal damage. The preliminary results of the current studies are promising, but more clinical investigations are needed to develop new and safe therapeutic strategies for diseases of the colon.

p28^GANK inhibits endoplasmic reticulum stress-induced cell death via enhancement of the endoplasmic reticulum adaptive capacity

It has been shown that oncoprotein p28GANK, which is consistently overexpressed in human hepatocellular carcinoma （HCC）, plays a critical role in tumorigenesis of HCC. However, the underlying mechanism remains unclear. Here, we demonstrated that p28GANK inhibits apoptosis in HCC cells induced by the endoplasmic reticulum （ER） stress. During ER stress, p28GANK enhances the unfolded protein response, promotes ER recovery from translational repression, and thereby facilitates cell＇s ability to cope with the stress conditions. Furthermore, p28GANK upregulates glucose-regulated protein 78 （GRP78）, a key ER chaperone protein, which subsequently enhances the ER folding capacity and promotes recovery from ER stress. We also demonstrated that p28GANK increases p38 mitogen-activated protein kinase and Akt phosphorylation, and inhibits nuclear factor kappa B （NF-κB） activation under ER stress, which in turn contributes to GRP78 upregulation. Taken together, our results indicate that p28GANK inhibits ER stress-induced apoptosis in HCC cells, at least in part, by enhancing the adaptive response and GRP78 expression. We propose that p28GANK has potential implications for HCC progression under the ER stress conditions.

Components of the mitogen-activated protein kinase cascade are activated in hepatic cells by Echinococcus multilocularis metacestode

AIM： To explore the effect of Echinococcusmultilocularis on the activation of mitogen-activated protein kinase （MAPK） signaling pathways and on livercell proliferation.METHODS： Changes in the phosphorylation of MAPKs and proliferating cell nuclear antigen （PCNA）expression were measured in the liver of patients withalveolar echinococcosis （AE）. MAPKs, MEK1/2 [MAPK/extracellular signal-regulated protein kinase （ERK）kinase] and ribosomal S6 kinase （RSK） phosphorylationwere detected in primary cultures of rat hepatocytesin contact in vitro with （1） E. multilocu/aris vesicle fluid（EmF）, （2）E. multilocularis-conditioned medium （EmCM）.RESULTS： In the liver of AE patients, ERK 1/2 andp38 MAPK were activated and PCNA expression wasincreased, especially in the vicinity of the metacestode.Upon exposure to EmF, p38, c-Jun N-terminal kinase（JNK） and ERK1/2 were also activated in hepatocytesin vitro, as well as MEK1/2 and RSK, in the absenceof any toxic effect. Upon exposure to EmCM, only JNKwas up-regulated.CONCLUSION： Previous studies have demonstratedan influence of the host on the MAPK cascade inE. multilocularis. Our data suggest that the reverse,i.e. parasite-derived signals efficiently acting onMAPK signaling pathways in host liver ceils, is actuallyoperating.

Reactive oxygen species: A double-edged sword in oncogenesis

Reactive oxygen species (ROS) are molecules or ions formed by the incomplete one-electron reduction of oxygen. Ofinterest, it seems that ROS manifest dual roles, cancer promoting or cancer suppressing, in tumorigenesis. ROS participate simultaneously in two signaling pathways that have inverse functions in tumorigenesis, Ras-Raf-MEK1/2-ERK1/2 signaling and the p38 mitogen-activated protein kinases (MAPK) pathway. It is well known that Ras-Raf-MEK1/2-ERK1/2 signaling is related to oncogenesis, while the p38 MAPK pathway contributes to cancer suppression, which involves oncogene-induced senescence, inflammationinduced cellular senescence, replicative senescence, contact inhibition and DNA-damage responses. Thus, ROS may not be an absolute carcinogenic factor or cancer suppressor. The purpose of the present review is to discuss the dual roles of ROS in the pathogenesis of cancer, and the signaling pathway mediating their role in tumorigenesis.

HBx activates FasL and mediates HepG2 cell apoptosis through MLK3-MKK7-JNKs signal module

AIM： To investigate the possible mechanism by which hepatitis B virus X protein （HBx） mediates apoptosis of HepG2 cells. METHODS： HBx expression vector pcDNA3.1-X was transfected into HepG2 cells to establish an HBx high- expression cellular model as pcDNA3.1-X transfected group. The pcDNA3.1-X and pSilencer3.1-shHBX （HBx antagonist） were cotransfected into HepG2 cells to es- tablish an HBx low-expression model as RNAi group. Untransfected HepG2 cells and HepG2 cells transfected with negative control plasmid were used as controls. Apoptosis rate, the expression of Fas/FasL signaling pathway-related proteins and the phosphorylation lev- els of MLK3, MKK7 and JNKs, which are upstream molecules of death receptor pathways and belong to the family of mitogen-activated protein kinases （MAPKs）,were measured in each group RESULTS： Compared with HepG2 cell group and RNAi group, apoptosis rate, the expression of Fas and FasL proteins, and the activation of MLK3, MKK7 and 3NKs were increased in the pcDNA3.1-X transfected group. The activation of JNKs and expression of FasL protein were inhibited in the pcDNA3.1-X transfected group when treated with a known JNK inhibitor, SP600125. When authors treated pcDNA3.1-X transfected group with K252a, a known MLK3 inhibitor, the activation of MLK3, MKK7 and 3NKs as well as expression of FasL protein was inhibited. Furthermore, cell apoptosis rate was also significantly declined in the presence of K252a in the pcDNA3.1-X transfected group. CONCLUSION： HBx can induce HepG2 cell apoptosis via a novel active MLK3-MKK7-JNKs signaling module to upregulate FasL protein expression.

Effects of lysophosphatidic acid on human colon cancer cells and its mechanisms of action

AIM： To study the effects of lysophosphatidic acid （LPA） on proliferation, adhesion, migration, and apoptosis in the human colon cancer cell line, SW480, and its mechanisms of action. METHODS： Methyl tetrazolium assay was used to assess cell proliferation. Flow cytometry was employed to detect cell apoptosis. Cell migration was measured by using a Boyden transweU migration chamber. Cell adhesion assay was performed in 96-well plates according to protocol. RESULTS： LPA significantly stimulated SW480 cell proliferation in a dose-dependent and timeependent manner compared with the control group （P 〈 0.05） while the mitogen-activated protein kinase （MAPK） inhibitor, PD98059, significantly blocked the LPA stimulation effect on proliferation. LPA also significantly stimulated adhesion and migration of SW480 cells in a dosedependent manner （P 〈 0.05）. Rho kinase inhibitor, Y-27632, significantly inhibited the upegulatory effect of LPA on adhesion and migration （P 〈 0.05）. LPA significantly protected cells from apoptosis induced by the chemotherapeutic drugs, cisplatin and 5-FU （P 〈 0.05）, but the phosphoinositide 3-kinase （PI3K） inhibitor, LY294002, significantly blocked the protective effect of LPA on apoptosis. CONCLUSION： LPA stimulated proliferation, adhesion,migration of 5W480 cells, and protected from apoptosis. The Ras/Raf-MAPK, G12/13-Rho-RhoA and PI3K- AKT/PKB signal pathways may be involved.

Molecular mechanism and functional consequences of lansoprazole-mediated heme oxygenase-1 induction

AIM： To investigate the molecular mechanism and functional consequences of heme oxygenase-1 （HO-1） activation by lansoprazole in endothelial cells and macrophages. METHODS： Expression of HO-1 mRNA was analyzed by Northern blotting. Western blotting was used to determine the HO-1 and ferritin protein levels. NADPH-dependent reactive oxygen species （ROS） formation was measured with lucigenin-enhanced chemiluminescence. HO-1 promoter activity in mouse fibroblasts, stably transfected with a 15-kb HO-1 gene that drives expression of the reporter gene luciferase, was assessed usingin vivo bioluminescence imaging. RESULTS： Lansoprazole levels in endothelial cells increased HO-1 mRNA and HO-1 protein levels in macrophages. In addition, lansoprazole-induced ferritin protein levels in both cell systems. Moreover, induction of the antioxidant proteins HO-1 and ferritin by lansoprazole was followed by a decrease in NADPH- mediated ROS formation. The radical scavenging properties of lansoprazole were diminished in the presence of the HO inhibitor, chromium mesoporphyrin IX. Induction of HO-1 gene expression by lansoprazole was not related to oxidative stress or to the activation of the mitogen-activated protein kinase pathway. However, the phosphatidylinositol 3-kinase inhibitor LY294002 showed a concentration-dependent inhibition of HO-1 mRNA and promoter activity.CONCLUSION： Activation of HO-1 and ferritin may account for the gastric protection of lansoprazole and is dependent on a pathway blocked by LY294002.

Effect of Yiguanjian decoction on cell differentiation and proliferation in CCl_4-treated mice

AIM： To investigate the cellular mechanisms of action of Yiguanjian （YGJ） decoction in treatment of chronic hepatic injury. METHODS： One group of mice was irradiated, and received enhanced green fluorescent protein （EGFP）- positive bone marrow transplants followed by 13 wk of CCh injection and 6 wk of oral YGJ administration. A second group of Institute for Cancer Research mice was treated with 13 wk of CCI4 injection and 6 wk of oral YGJadministration. Liver function, histological changes in the liver, and Hyp content were analyzed. The expres- sion of m-smooth muscle actin （α-SMA）, F4/80, albumin （AIb）, EGFP, mitogen-activated protein kinase-2 （PKM2）, Ki-67, fetoprotein （AFP）, monocyte chemotaxis pro- tein-1 and CC chemokine receptor 2 were assayed. RESULTS： As hepatic damage progressed, EGFP-po- sitive marrow cells migrated into the liver and were mainly distributed along the fibrous septa. They showed a conspicuous coexpression of EGFP with ^-SMA and F4/80 but no coexpression with AIb. Moreover, the expression of PKM2, AFP and Ki-67 was enhanced dy- namically and steadily over the course of liver injury. YGJ abrogated the increases in the number of bone marrow-derived fibrogenic cells in the liver, inhibited expression of both progenitor and mature hepatocyte markers, and reduced fibrogenesis. CONCLUSION： YGJ decoction improves liver fibrosis by inhibiting the migration of bone marrow cells into the liver as well as inhibiting their differentiation and suppressing the proliferation of both progenitors and hepatocytes in the injured liver.

Down-regulation of HIV-1 Infection by Inhibition of the MAPK Signaling Pathway

The human immunodeficiency virus type 1 （HIV-1） can interact with and exploit the host cellular machinery to replicate and propagate itself. Numerous studies have shown that the Mitogen-activated protein kinase （MAPK） signal pathway can positively regulate the replication of HIV-1, but exactly how each MAPK pathway affects HIV-1 infection and replication is not understood. In this study, we used the Extracellular signal-regulated kinase （ERK） pathway inhibitor, PD98059, the Jun N-terminal kinase （JNK） pathway inhibitor, SP600125, and the p38 pathway inhibitor, SB203580, to investigate the roles of these pathways in HIV-1 replication. We found that application of PD98059 results in a strong VSV-G pseudotyped HIV-1NL4-3 luciferase reporter virus and HIV-1NL4-3 virus inhibition activity. In addition, SB203580 and SP600125 also elicited marked VSV-G pseudotyped HIV-INL4-3 luciferase reporter virus inhibition activity but no HIV-1NL4-3 virus inhibition activity. We also found that SB203580 and SP600125 can enhance the HIV-1 inhibition activity of PD98059 when cells were treated with all three MAPK pathway inhibitors in combination. Finally, we show that HIV-1 virus inhibition activity of the MAPK pathway inhibitors was the result of the negative regulation of HIV-1 LTR promoter activity.

The effect of C-terminal fragment of JNK2 on the stability of p53 and cell proliferation

The basal activity of JNK is low in normal growing cells and inactivated JNK targets p53 for ubiquitination. To elucidate if the C-terminal part of JNK is responsible for its binding to p53, the low background tet-off inducible NIH3T3 cell line was selected by luciferase reporter gene and a double stable C-JNK Aa (203-424) cell line was established. After withdrawing tetracycline, the C-JNK fragment expression was induced and cell growth was dramati- cally inhibited 24 h later. However, the expresion of p53 was found to be increased after the induction of C-JNK fragment, evaluated by transfecting p21waf-luciferase reporter genes. Our further studies showed that C-JNK fragment could form complex with p53 both in vivo and in vitro. Induction of C-JNK fragment in vivo can increase p53 stability by inhibiting p53 ubiquitination.

Lentiviral vector-mediated down-regulation of IL-17A receptor in hepatic stellate cells results in decreased secretion of IL-6

AIM: To investigate the mechanism of interleukin (IL)-6 secretion through blocking the IL-17A/IL-17A recepto (IL-17RA) signaling pathway with a short hairpin RNA (shRNA) in hepatic stellate cells (HSCs) in vitro . METHODS: HSCs were derived from the livers of adul male Sprague-Dawley rats. IL-6 expression was evalu ated using real-time quantitative polymerase chain reaction and enzyme linked immunosorbent assay. The phosphorylation activity of p38 mitogen activated pro tein kinases (MAPK) and extracellular regulated pro tein kinases (ERK) 1/2 upon induction by IL-17A and suppression by IL-17RA shRNA were examined using Western blotting.RESULTS: IL-6 expression induced by IL-17A was significantly increased compared to control in HSCs (P < 0.01 in a dose-dependent manner). Suppression of IL17RA using lentiviral-mediated shRNA inhibited IL-6 expression induced by IL-17A compared to group with only IL-17A treatment (1.44 ± 0.17 vs 4.07 ± 0.43, P < 0.01). IL-17A induced rapid phosphorylation of p38 MAPK and ERK1/2 after 5 min exposure, and showed the strongest levels of phosphorylation of p38 MAPK and ERK1/2 at 15 min in IL-17A-treated HSCs. IL-6 mRNA expression induced by IL-17A (100 ng/mL) for 3 h exposure was inhibited by preincubation with specific inhibitors of p38 MAPK (SB-203580) and ERK1/2 (PD-98059) compared to groups without inhibitors preincubation (1.67 ± 0.24, 2.01 ± 0.10 vs 4.08 ± 0.59, P < 0.01). Moreover, lentiviral-mediated IL-17RA shRNA 1 inhibited IL-17A-induced IL-6 mRNA expression compared to random shRNA in HSCs (1.44 ± 0.17 vs 3.98 ± 0.68, P < 0.01). Lentiviral-mediated IL17RA shRNA 1 inhibited phosphorylation of p38 MAPK and ERK1/2 induced by 15 min IL-17A (100 ng/mL) exposure. CONCLUSION: Down-regulation of the IL-17RA receptor by shRNA decreased IL-6 expression induced by IL-17A via p38 MAPK and ERK1/2 phosphorylation in HSCs. Suppression of IL-17RA expression may be a strategy to reduce the inflammatory response induced by IL-17A in the liver.