Physiological roles of mitogen-activated-protein-kinase-activated p38-regulated/activated protein kinase

Mitogen-activated protein kinases(MAPKs)are a family of proteins that constitute signaling pathways involved in processes that control gene expression,cell division, cell survival,apoptosis,metabolism,differentiation and motility.The MAPK pathways can be divided into conventional and atypical MAPK pathways.The first group converts a signal into a cellular response through a relay of three consecutive phosphorylation events exerted by MAPK kinase kinases,MAPK kinase,and MAPK.Atypical MAPK pathways are not organized into this three-tiered cascade.MAPK that belongs to both conventional and atypical MAPK pathways can phosphorylate both non-protein kinase substrates and other protein kinases.The latter are referred to as MAPK-activated protein kinases.This review focuses on one such MAPK-activated protein kinase,MAPK-activated protein kinase 5(MK5)or p38-regulated/activated protein kinase(PRAK).This protein is highly conserved throughout the animal kingdom and seems to be the target of both conventional and atypical MAPK pathways.Recent findings on the regulation of the activity and subcellular localization,bona fide interaction partners and physiological roles of MK5/PRAK are discussed.

Influence of Ren and Du meridian electro-acupuncture on neural stem cell proliferation and extracellular signal-regulated kinase pathway in a rat model of focal cerebral ischemia injury

BACKGROUND： Studies have shown that electro-acupuncture at the Ren meridian could improve proliferation of subventricular zone neural stem cells in cerebral-ischemic rats. However, there are few reports on the influence of electro-acupuncture at the Du meridian on neural stem cell proliferation. OBJECTIVE： To observe the influence of electro-acupuncture at Ren and Du meridians on neural stem cell proliferation in the subventricular zone and altered signal transduction in cerebral ischemia rats. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Laboratory of Human Anatomy, Medical College of Sun Yat-sen University from May 2006 to February 2008. MATERIALS： Mouse anti-rat bromodeoxyuridine （BrdU） monoclonal antibody was provided by Sigma, USA; mouse anti-rat nestin monoclonal antibody and extracellular signal-regulated protein kinase （ERK） specific inhibitor PD98059 were provided by Calbiochem, Germany; acupuncture needle was provided by Suzhou Acupuncture Supplies, China. METHODS： A total of 126 rats were randomly assigned to four groups： model （n = 36）, Du meridian （n = 36）, Ren/Du meridian （n = 36）, and Ren/Du meridian ＋ PD98059 （n = 18）. Rats in the Ren/Du meridian ＋ PD98059 group were observed on days 7 （n = 6） and 14 （n = 12） after cerebral ischemia injury. Rats in the model, Du meridian, and Ren/Du meridian groups were observed on days 7, 14, and 28 after cerebral ischemia injury, with 12 rats per group at each time point. Thread occlusion was used to establish middle cerebral artery occlusion models. Electro-acupuncture was performed at Renzhong （DU 26） and Baihui （DU 20） acupoints in the Du meridian group, as well as Chengjiang （RN 24）, Guanyuan （RN 4）, Renzhong, and Baihuiacupoints in the Ren/Du meridian and Ren/Du meridian ＋ PD98059 groups 2 days after model establishment. In addition, electro-acupuncture stimulation with disperse-dense waves was performed, with 30 Hz disperse wave, 100 Hz dense wave, and 5 V intensity for 20 minutes. Rats in the Ren/Du meridian ＋ PD98059 group were treated with 0.2 pg PD98059 injection into the subventricular zone, 2 pL per rat. Rats in the model group were not treated with electro-acupuncture. MAIN OUTCOME MEASURES： BrdU/nestin immunofluorescent staining was used to detect proliferating neural stem cells in the subventricular zone of cerebral ischemia rats; Western blot was used to determine phosphorylated ERK1 and 2 （pERK1/2） expression in the subventricular zone. RESULTS： On days 14 and 28 after cerebral ischemia, there were significantly more BrdU-positive and BrdU/nestin-positive cells in the Ren/Du meridian group compared with the Du meridian group （P 〈 0.05）. PD98059 decreased the number of BrdU-positive and BrdU/nestin-positive cells induced by electro-acupuncture at the/：ten and Du meridians （P 〈 0.05）. On days 7, 14, and 28 after treatment, pERK1/2 expression was significantly greater in the Du meridian and Ren/Du meridian groups compared with the model group （P 〈 0.05）. The promoting effect of electro-acupuncture at Ren and Du meridians on ERK1/2 phosphorylation was superior to electro-acupuncture at the Du meridian alone on day 14 after model induction （P 〈 0.05）. However, PD98059 completely abolished the promoting effect of electro-acupuncture at Ren/Du meridians on pERK1/2 expression （P 〈 0.05）. CONCLUSION： Electro-acupuncture at Ren and Du meridians increased proliferation of subventricular zone neural stem cells, which was related to activation of the ERK pathway in a rat model of cerebral ischemia 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.

Optimized new Shengmai powder(优化新生脉散方) inhibits myocardial fibrosis in heart failure by regulating the rat sarcoma/rapidly accelerated fibrosarcoma/mitogen-activated protein kinase kinase/extracellular regulated protein kinases signaling pathway

OBJECTIVE: Exploring the effect of Optimized New Shengmai powder(优化新生脉散方, ONSMP) on myocardial fibrosis in heart failure(HF) based on rat sarcoma(RAS)/rapidly accelerated fibrosarcoma(RAF)/mitogen-activated protein kinase kinase(MEK)/extracellular regulated protein kinases(ERK) signaling pathway. METHODS: Randomized 70 Sprague-Dawley rats into sham(n = 10) and operation(n = 60) groups, then established the HF rat by ligating the left anterior descending branch of the coronary artery. We randomly divided the operation group rats into the model, ONSMP [including low(L), medium(M), and high(H) dose], and enalapril groups. After the 4-week drug intervention, echocardiography examines the cardiac function and calculates the ratios of the whole/left heart to the rat's body weight. Finally, we observed the degree of myocardial fibrosis by pathological sections, determined myocardium collagen(COL) Ⅰ and COL Ⅲ content by enzyme-linked immunosorbent assay, detected the m RNA levels of COL Ⅰ, COL Ⅲ, α-smooth muscle actin(α-SMA), and c-Fos proto-oncogene(c-Fos) by universal real-time, and detected the protein expression of p-RAS, p-RAF, p-MEK1/2, p-ERK1/2, p-ETS-like-1 transcription factor(p-ELK1), p-c-Fos, α-SMA, COL Ⅰ, and COL Ⅲ by Western blot. RESULTS: ONSMP can effectively improve HF rat's cardiac function, decrease cardiac organ coefficient, COL volume fraction, and COL Ⅰ/Ⅲ content, down-regulate the m RNA of COL Ⅰ/Ⅲ, α-SMA and c-Fos, and the protein of p-RAS, p-RAF, p-MEK1/2, p-ERK1/2, p-ELK1, c-Fos, COL Ⅰ/Ⅲ, and α-SMA. CONCLUSIONS: ONSMP can effectively reduce myocardial fibrosis in HF rats, and the mechanism may be related to the inhibition of the RAS/RAF/MEK/ERK signaling pathway.

Ceramide from sphingomyelin hydrolysis differentially mediates mitogen-activated protein kinases (MAPKs) activation following cerebral ischemia in rat hippocampal CA1 subregion

Objective： To explore the role that ceramide plays in the activation of mitogen-activated protein kinases （MAPKs） during cerebral ischemia and reperfusion. Methods： Rats were subjected to ischemia by the fourvessel occlusion （4-VO） method. The sphingomyelinase inhibitor TPCK was administered to the CA1 subregion of the rat hippocampus before inducing ischemia. Western blot was used to examine the activity of extracellular- signal regulated kinase （ERK） and c-Jun N-terminal protein kinase （JNK） using antibodies against ERK, JNK and diphosphorylated ERK and JNK. Results： At lh reperfusion post-ischemia, JNK reached its peak activity while ERK was undergoing a sharp inactivation （P 〈 0.05）. The level of diphosphorylated JNK was significantly reduced but the sharp inactivation of ERK was visibly reversed （P 〈 0.05） by the sphingomyelinase inhibitor. Conclusion： The ceramide signaling pathway is up-regulated through sphingomyelin hydrolysis in brain ischemia, promoting JNK activation and suppressing ERK activation, culminating in the ischemic lesion.

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.

Response of Subcutaneous Xenografts of Endometrial Cancer in Nude Mice to Inhibitors of Phosphatidylinositol 3-Kinase/Akt and Mitogen-Activated Protein Kinase (MAPK) Pathways: An Effective Therapeutic Strategy for Endometrial Cancer

Objective: This study was designed to explore whether inhibition of the extracellular-regulated kinase (ERK) and phosphatidylinositol-3-kinase (PI3K) signaling pathways can inhibit the growth of xenografts of endometrial cancer cell lines with different estrogen receptors (ER) profiles in vivo and to provide preliminary laboratory basis for the probability of endometrial adenocarcinoma treatment with blockage of the two pathways, especially to endometrial cancer with low ER status. Methods: Human endometrial cancer Ishikawa bearing ER and HEC-1Awith low ER status cells were subcutaneously injected into BALB/c nude mice to establish endometrial cancer xenograft tumor models. The effects of PI3K/Akt inhibitor LY294002, MAPK/ERK1/2 inhibitor PD-98059 and their combinations on the growth of the xenograft tumors and apoptotic state of Ishikawa and HEC-1Acells were tested in vivo using the inhibitory rate, the terminal deoxynucleotidyl transferase-mediated nick-end labeling assay, H/E-stain. Western blot analysis was used to detect the alterations of activated ERK (P-ERK) and AKT (P-AKT) during this process. Results: LY294002, a PI3K/Akt pathway inhibitor, induced significant suppression in the growth of both Ishikawa and HEC-1Acell xenograft tumors, concomitant with increased apoptosis in xenografts as evidenced by TUNEL. A similar effect was also observed when the MAPK/ERK1/2 signaling pathway was inhibited by PD98059. Concurrent inhibition of the PI3K/Akt and MAPK/ERK1/2 pathways showed enhanced anti-tumor effects in vivo as indicated by increased apoptosis. At the same time, the levels of P-ERK and P-AKT in both xenograft tumors decreased, and their levels in combination group was the lowest. Conclusions: PD98059, LY294002 and their combinations showed remarkable inhibitory effects on xenograft tumors of endometrial carcinoma cell lines with different expression status of ER in vivo through blockage of PI3K/Akt and MAPK/ERK1/2 signaling pathways. This suggests that targeting these pathways may be an effective therapeutic strategy against endometrial carcinomas, especially for ER-negative cancers which show poor response to endocrinal therapy.

SOX7靶向ERK1/2/PD-L1通路抑制结直肠癌血管生成

目的探讨性别决定区Y框蛋白7(SOX7)对结直肠癌血管生成的影响及潜在作用机制。方法应用免疫荧光检测结直肠癌患者组织样本中SOX7表达水平,之后通过裸鼠、转染SOX7 mimic的人结直肠癌细胞系SW480细胞和人脐静脉内皮细胞(HUVEC)共培养进一步研究。用Western-blot验证SOX7与ERK1/2/PD-L1对结直肠癌细胞的相关蛋白表达的影响。用CCK8检测SOX7与ERK1/2/PD-L1对HUVEC增殖的影响。通过体外内皮细胞成管实验测定SOX7与ERK1/2/PD-L1对肿瘤血管生成的影响。结果SOX7在人结直肠癌组织中表达被抑制(P<0.01),同时SOX7的过表达抑制了小鼠体内肿瘤生长(P<0.01)。SW480细胞中SOX7的过表达抑制了ERK1/2、c-Jun的表达,并在ERK1/2的激动剂Senkyunolide I的作用下上调了SW480细胞的ERK1/2、c-Jun蛋白表达(P<0.01),逆转了SOX7对SW480细胞中ERK1/2、c-Jun蛋白表达的影响(P<0.01)。HUVEC中SOX7抑制了PD-L1、V-EGFR2、p-PI3K、HIF-1α的蛋白表达,Senkyunolide I上调了HUVEC的PD-L1、V-EGFR2、p-PI3K、HIF-1α的蛋白表达,并逆转了SOX7对HUVEC中上述相关蛋白表达的影响(P<0.01)。PD-1/PD-L1 Inhibitor 3抑制了PD-L1、V-EGFR2、p-PI3K、HIF-1α的蛋白表达,SOX7过表达在PD-1/PD-L1 Inhibitor 3的影响下并没有表现出抑制作用。CCK8实验结果显示SOX7过表达显著抑制了HUVEC的增殖能力,Senkyunolide I作用下的两组HUVEC增殖能力较SOX7 NC组与SOX7 mimic组明显上升,PD-1/PD-L1 Inhibitor 3作用下的两组HUVEC增殖能力较SOX7 NC组与SOX7 mimic组明显下降,以上均有明显统计学差异(P<0.01)。成管实验结果显示SOX7过表达抑制了HUVEC的血管生成,Senkyunolide I强烈加速了血管生成,而PD-1/PD-L1 Inhibitor 3血管生成则被显著抑制,以上均有明显统计学差异(P<0.01)。结论SOX7通过ERK1/2/PD-L1通路抑制结直肠肿瘤的增殖和血管生成,SOX7可能是晚期CRC患者临床治疗中潜在的抗血管生成靶点。

Hepatitis B virus X protein up-regulates tumor necrosis factor-α expression in cultured mesangial cells via ERKs and NF-κB pathways

Objective:To investigate the effects of hepatitis B virus(HBV)X protein(HBx)on the expression of tumor necrosis factor-α(TNF-α)in glomerular mesangial cells(GMCs)and the underlying intracellular signal pathways.Methods:The plasmid pCI-neo-X that carries the X gene of hepatitis B virus was transfected into cultured GMCs.HBx expression in the transfected GMCs was assessed by Western-blot.TNF-αprotein and mRNA were assessed by ELISA and semi-quantitative RT-PCR,respectively.Three kinase inhibitors-U0126,an inhibitor of extracellular signal-regulated kinases(ERKs);lactacvstin,an inhibitor of nuclear factor-κB(NF-κB);and SB203580,a selective inhibitor of p38 MAP kinase(p38 MAPK)were used to determine which intracellular signal pathways may underlie the action of HBx on TNF-αexpression in transfected GMCs.Results:A significant increase in HBx expression in pCI-neo-X transfected GMCs was detected at 36 h and 48 h,which was not affected by any of those kinase inhibitors mentioned above.A similar increase in the expression of both TNF-αprotein and mRNA was also observed at 36 h and 48 h,which was significantly decreased in the presence of U0126 or lactacytin,but not SB203580.Conclusions:HBx upregulates TNF-αexpression in cultured GMCs,possibly through ERKs and NF-κB pathway,but not p38 MAPK pathway.

基于EGFR/MAPK/ERK信号通路探讨鳖甲煎丸对MHCC-97H肝癌细胞皮下瘤的抑瘤作用

目的基于表皮生长因子受体(epidermal growth factior receptor,EGFR)/丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)/细胞外信号调节激酶(extracellular signal-regulated kinase,ERK)信号通路探究鳖甲煎丸对MHCC-97H肝癌细胞皮下瘤的抑瘤作用及作用机制。方法选取30只雄性BLAB/c裸鼠,建立MHCC-97H肝癌细胞皮下瘤模型。造模成功后随机分为模型组,鳖甲煎丸低、中、高剂量组(0.55、1.1、2.2 g/kg),西药组(乐伐替尼4 mg/kg+吉非替尼80 mg/kg),每组6只。鳖甲煎丸低、中、高剂量组灌胃2次/d,西药组每周灌胃5 d,模型组予以等量生理盐水2次/d灌胃,每组连续干预2周。观察大鼠一般情况;计算各组大鼠抑瘤率;HE染色观察病理形态学变化;RT-qPCR检测瘤体组织中EGFR、丝裂原活化蛋白质激酶激酶(mitogen-activated protein kinase kinase,MEK)、ERK1、ERK2 mRNA表达水平;Western blot检测EGFR、磷酸化的EGFR(p-EGFR)、MEK、磷酸化的MEK(p-MEK)、ERK1、ERK2、磷酸化的ERK1/2(p-ERK1/2)、基质金属蛋白酶-1(matrix metalloproteinase-1,MMP-1)、细胞周期蛋白D1(cell cycle protein D1,Cyclin D1)、神经型钙黏附蛋白(N-cadherin)、上皮型钙黏附蛋白(E-cadherin)相对表达水平。结果与模型组比较,鳖甲煎丸低、中、高剂量组及西药组精神、反应、进食饮水等情况均明显改善。与第0天比较,各组第14天体质量明显降低(P<0.01)。与模型组、鳖甲煎丸低剂量组比较,鳖甲煎丸中、高剂量组和西药组瘤体质量减轻(P<0.05,P<0.01)。鳖甲煎丸低、中、高剂量组和西药组抑瘤率分别为20%、47.73%、55.91%、75.45%。与模型组比较,鳖甲煎丸低、中、高剂量组及西药组肿瘤细胞排列疏松,边界模糊,细胞核固缩、破裂,其中西药组最明显。与模型组比较,鳖甲煎丸低、中、高剂量组和西药组EGFR、MEK、ERK1、ERK2 mRNA表达水平明显下降(P<0.01);与鳖甲煎丸低剂量组比较,鳖甲煎丸高剂量组和西药组EGFR、MEK、ERK1、ERK2 mRNA表达水平显著降低(P<0.01),鳖甲煎丸中剂量组ERK1 mRNA表达水平显著降低(P<0.01);与鳖甲煎丸中剂量组比较,西药组EGFR、ERK2 mRNA表达水平降低(P<0.05,P<0.01)。与模型组比较,鳖甲煎丸中、高剂量组和西药组p-EGFR/EGFR、p-MEK/MEK、p-ERK1/ERK1、p-ERK2/ERK2、MMP-1、Cyclin D1、N-cadherin蛋白相对表达水平下降(P<0.05,P<0.01),E-cadherin蛋白相对表达水平明显升高(P<0.01)。与鳖甲煎丸高剂量组比较,西药组p-EGFR/EGFR、p-ERK1/ERK1、MMP-1、Cyclin D1、N-cadherin蛋白相对表达水平明显下降(P<0.01),E-cadherin蛋白相对表达水平升高(P<0.05)。结论鳖甲煎丸可能通过抑制EGFR/MAPK/ERK信号通路激活,从而下调MMP-1、Cyclin D1、N-cadherin蛋白,上调E-cadherin蛋白表达,进而对MHCC-97H肝癌细胞皮下瘤产生显著的抑制作用。

哈蟆油酶解物激活MAPK/ERK信号凋亡途径修复皮质酮诱导HT-22细胞损伤作用

为研究哈蟆油(Oviductus Ranae,OR)对海马神经元细胞保护作用机制,该研究通过皮质酮(Corticosterone,CORT)诱导HT-22细胞损伤模型探究哈蟆油酶解物对小鼠海马神经元细胞(HT-22)细胞损伤模型的保护作用及其作用机制。采用CORT与HT-22细胞共同培养建立HT-22细胞损伤模型,给予哈蟆油酶解物再次孵育,将ERK信号通路抑制剂PD98059加入HT-22细胞中。采用MTT法、Hochest 33258染色、流式细胞术、Western blot技术检测HT-22细胞凋亡情况和相关蛋白表达以及MAPK/ERK信号通路蛋白表达。结果显示高水平CORT能够诱导HT-22细胞损伤,哈蟆油酶解物能够使CORT诱导的HT-22细胞活力提升62.5%~87.5%,凋亡比例降低50%~70%。哈蟆油酶解物能够上调BCL-2、P-ERK1/2蛋白表达,同时下调BAX、Caspase-3、Caspase-9的蛋白表达。上述结果表明,高水平CORT是通过抑制MAPK/ERK信号通路促进凋亡的发生从而诱导HT-22细胞损伤,哈蟆油酶解物能够通过激活MAPK/ERK信号通路调节BLC-2、BAX、Caspase-3、Caspase-9凋亡相关蛋白的表达进而抑制凋亡的发生减轻神经元损伤,该作用机制为哈蟆油发挥抗抑郁作用的关键途径之一。

Protein tyrosine phosphatase 1B regulates migration of ARPE-19 cells through EGFR/ERK signaling pathway

AIMTo evaluate whether protein tyrosine phosphatase 1B (PTP1B) contributed to initiate human retinal pigment epithelium cells (A)-19 migration and investigate the signaling pathways involved in this process.METHODSARPE-19 cells were cultured and treated with the siRNA-PTP1B. Expression of PTP1B was confirmed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). AG1478 [a selective inhibitor of epidermal growth factor receptor (EGFR)] and PD98059 (a specific inhibitor of the activation of mitogen-activated protein kinase) were used to help to determine the PTP1B signaling mechanism. Western blot analysis verified expression of EGFR and extracellular signal-regulated kinase (ERK) in ARPE-19 cells. The effect of siRNA-PTP1B on cell differentiation was confirmed by immunostaining for &#x003b1;-smooth muscle actin (&#x003b1;-SMA) and qRT-PCR. Cell migration ability was analyzed by transwell chamber assay.RESULTSThe mRNA levels of PTP1B were reduced by siRNA-PTP1B as determined by qRT-PCR assay. SiRNA-PTP1B activated EGFR and ERK phosphorylation. &#x003b1;-SMA staining and qRT-PCR assay demonstrated that siRNA-PTP1B induced retinal pigment epithelium (RPE) cells to differentiate toward better contractility and motility. Transwell chamber assay proved that PTP1B inhibition improved migration activity of RPE cells. Treatment with AG1478 and PD98059 abolished siRNA-PTP1B-induced activation of EGFR and ERK, &#x003b1;-SMA expression and cell migration.CONCLUSIONPTP1B inhibition promoted myofibroblast differentiation and migration of ARPE-19 cells, and EGFR/ERK signaling pathway played important role in migration process.

Sphingosine-1-Phosphate Protects Against the Development of Cardiac Remodeling via Sphingosine Kinase 2 and the S1PR2/ERK Pathway

Objective:Cardiac remodeling is a common pathological change in various cardiovascular diseases and can ultimately result in heart failure.Thus,there is an urgent need for more effective strategies to aid in cardiac protection.Our previous work found that sphingosine-1-phosphate(S1P)could ameliorate cardiac hypertrophy.In this study,we aimed to investigate whether S1P could prevent cardiac fibrosis and the associated mechanisms in cardiac remodeling.Methods:Eight-week-old male C57BL/6 mice were randomly divided into a sham,transverse aortic constriction(TAC)or a TAC+S1P treatment group.Results:We found that S1P treatment improved cardiac function in TAC mice and that the cardiac fibrosis ratio in the TAC+S1P group was significantly lower and was accompanied by a decrease inα-smooth muscle actin(α-SMA)and collagen type I(COL I)expression compared with the TAC group.We also found that one of the key S1P enzymes,sphingosine kinase 2(SphK2),which was mainly distributed in cytoblasts,was downregulated in the cardiac remodeling case and recovered after S1P treatment in vivo and in vitro.In addition,our in vitro results showed that S1P treatment activated extracellular regulated protein kinases(ERK)phosphorylation mainly through the S1P receptor 2(S1PR2)and spurred p-ERK transposition from the cytoplasm to cytoblast in H9c2 cells exposed to phenylephrine.Conclusion:These findings suggest that SphK2 and the S1PR2/ERK pathway may participate in the anti-remodeling effect of S1P on the heart.This work therefore uncovers a novel potential therapy for the prevention of cardiac remodeling.

miRNA-7-EGFR/ERK通路用于卵巢癌治疗的研究进展

卵巢癌(OC)在女性生殖系统肿瘤中致死率最高,治疗多选择手术切除加辅助化疗,然而易出现耐药性,导致患者预后差。miRNA-7在卵巢癌细胞中低表达,通过靶向表皮生长因子受体(EGFR)/细胞外调节蛋白激酶(ERK)信号通路发挥抗肿瘤作用。本综述介绍miRNA-7-EGFR/ERK通路在卵巢癌治疗中的作用,为卵巢癌的治疗提供新的思路。

Calcitonin gene-related peptide induces proliferation and monocyte chemoattractant protein-1 expression via extracellular signal-regulated kinase activation in rat osteoblasts

Background Calcitonin gene-related peptide （CGRP）, a sensory neuropeptide, affects osteoblast proliferation and bone formation. However, the mechanisms are not fully understood. Monocyte chemoattractant protein-1 （MCP-1） is a chemokine that stimulates the migration of monocytes and plays important roles in regulating bone remolding during fracture repair. In this study, we investigated the effects of CGRP on proliferation and MCP-1 expression in cultured rat osteoblasts. Methods Primary rat osteoblasts were isolated from fetal rats calvariae. Cells were exposed to gradient concentrations （10^-9 to 10^-7 mol/L） of CGRP. Protein and mRNA levels of MCP-1 were quantified by Western blotting and semiquantitative reverse transcdption-polymerase chain reaction, respectively. The protein level of MCP-1 was investigated and compared in cell culture media by enzyme linked immunosorbent assay （ELISA）. Phospho-extracellular signal-regulated kinase （ERK） expression was detected by Western blotting. Cell proliferative activity was measured by 3-（4,5-dimethylthiazol-2-yl）-2, 5-diphenyl tetrazolium bromide （MTT） and BrdU assay. The effects of MAPK/ERK kinase （MEK）-inhibitor U0126 on CGRP-induced MCP-1 expression in primary rat osteoblasts were examined. Results CGRP effectively enhanced primary rat osteoblast proliferation and led to significant increases in the expression of MCP-1 mRNA and protein in time- and dose-dependent manners. CGRP activated the ERK pathway. Pretreatment of cultured rat osteoblasts with MEK inhibitor U0126 resulted in dose-dependent inhibitions of CGRP-induced MCP-1 mRNA and protein levels. Thus, CGRP promoted cell proliferation and stimulated MCP-1 expression in cultured rat osteoblasts. Conclusion These studies document novel links between CGRP and MCP-1 and illuminate the effects of CGRP in regulating bone remodeling.

Glucocorticoid modulation of extracellular signal-regulated protein kinase 1/2 and p38 in human ovarian cancer HO-8910 cells

Objective To investigate the signaling pathway through testing the effects of dexamethasone (Dex) on the activation of the extracellular signal-regulated protein kinase 1/2 (ERK1/2) and p38 kinase (p38) in HO-8910 cells.Methods Activation of the ERK1/2 and p38 was detected by Western blotting using the antibodies against the total ERK1/2 and p38 mitogen-activated protein kinases (MAPKs) protein and the phosphorylated forms of them. Results Dex could suppress the activation of ERK1/2, while enhance the activation of p38 rapidly and strongly in a dose- and time- dependent manner. Neither effect could be blocked by RU486, the antagonist of glucocorticoid receptor (GR).Conclusion Dex has rapid effects on the activation of ERK1/2 and p38, and these effects are not mediated by GR.

紫草素调节NF-κB/ERK信号通路对膝关节骨性关节炎大鼠炎症反应的影响

目的:通过构建膝关节骨性关节炎大鼠模型,探究紫草素对膝关节骨性关节炎大鼠炎症反应、NF-κB/细胞外调节蛋白激酶(ERK)通路的影响,以及NF-κB/ERK信号通路作为紫草素作用新靶点的可能性。方法:选取72只SD雄性大鼠,随机分为假手术组、关节炎组、尼美舒利组、紫草素组、紫草素+ERK激活组、紫草素+NF-κB激活组,每组12只。构建膝关节骨性关节炎大鼠模型,评估各组大鼠关节炎指数,判断模型构建情况;番红固绿、HE染色观察各组大鼠膝关节软骨病理学情况;ELISA检测各组大鼠血清和软骨组织中IL-1β、IL-6、TNF-α水平;Western blot检测软骨组织中NF-κB p65、ERK、p-NF-κB p65、p-ERK蛋白表达量。结果:假手术组大鼠软骨组织无明显突起,番红染色全染;与假手术组相比,关节炎组大鼠软骨出现突起,染色完全失染,关节炎指数、血清和软骨组织中TNF-α、IL-6、IL-1β含量、软骨组织NF-κB p65、ERK蛋白磷酸化程度显著升高(P<0.05);与关节炎组相比,尼美舒利组、紫草素组大鼠软骨组织逐渐恢复,番红染色增多,关节炎指数、血清和软骨组织中TNF-α、IL-6、IL-1β含量、软骨组织NF-κB p65、ERK蛋白磷酸化程度显著降低(P<0.05);与紫草素组相比,紫草素+ERK激活组、紫草素+NF-κB激活组大鼠软骨组织恢复慢,番红染色失染严重,关节炎指数、血清和软骨组织中TNF-α、IL-6、IL-1β含量、软骨组织NF-κB p65、ERK蛋白磷酸化程度显著升高(P<0.05);紫草素组与尼美舒利组相比,各项指标差异无统计学意义(P>0.05)。结论:紫草素可通过调控NF-κB/ERK通路抑制相关蛋白激活,从而缓解膝关节骨性关节炎。

MicroRNA-133b调节FGFR1-ERK1/2-SOX2信号通路对裸鼠肺癌NCI-H1975细胞移植瘤生长的影响

目的探讨microRNA-133b(miR-133b)对裸鼠肺癌NCI-H1975细胞移植瘤生长的抑制作用以及对成纤维细胞生长因子受体1-细胞外信号调节激酶1/2-性别决定区Y-box蛋白2信号通路(FGFR1-ERK1/2-SOX2)的影响。方法q RT-PCR检测人肺成纤维细胞、肺癌细胞株miR-133b表达。miR-133b过表达NCIH1975细胞。将NCI-H1975细胞分为对照组、mimic NC组、miR-133b mimic组、miR-133b mimic+pcDNA3.1组、miR-133b mimic+pcDNA3.1 FGFR1组。CCK-8法检测NCI-H1975细胞增殖抑制率,Transwell实验观察NCI-H1975细胞侵袭、迁移情况。复制裸鼠移植瘤模型并分组,将裸鼠分为对照组、mimic NC组、miR-133b mimic组、miR-133b mimic+AZD4547组,观察各组裸鼠肿瘤体积与重量,HE染色观察各组裸鼠肿瘤组织变化,TUNEL检测肿瘤组织细胞凋亡情况,免疫组织化学法观察裸鼠肿瘤组织Ki-67、Cyclin D1、VEGF-A的表达,Western blotting检测各组肿瘤组织FGFR1、p-ERK1/2/ERK1/2、SOX2蛋白相对表达量。结果与人肺成纤维细胞HLF-α比较,肺癌细胞株NCI-H1975、A427、NGE-1、A549中miR-133b mRNA相对表达量降低(P<0.05),其中以NCI-H1975细胞中miR-133b mRNA相对表达量最低。miR-133b mimic组miR-133b mRNA相对表达量较对照组和mimic NC组升高(P<0.05)。miR-133b可通过负调控FGFR1抑制肺癌NCIH1975细胞增殖和迁移。miR-133b mimic组移植瘤重量较对照组降低、体积缩小,miR-133b mimic+AZD4547组移植瘤重量较miR-133b mimic组降低、体积缩小(P<0.05)。miR-133b mimic组空泡样变性程度较对照组、mimic NC组减轻(P<0.05),miR-133b mimic+AZD4547组空泡样变性程度较miR-133b mimic组减轻(P<0.05)。miR-133b mimic组肿瘤组织细胞凋亡率较对照组升高(P<0.05),miR-133b mimic+AZD4547组肿瘤组织细胞凋亡率较miR-133b mimic组升高(P<0.05)。miR-133b mimic组VEGF-A、Cyclin D、Ki-67阳性细胞比例较对照组降低(P<0.05),miR-133b mimic+AZD4547组VEGF-A、Cyclin D、Ki-67阳性细胞比例较miR-133b mimic组降低(P<0.05)。miR-133b mimic组FGFR1、p-ERK1/2/ERK1/2、SOX2蛋白相对表达量较对照组降低(P<0.05),miR-133b mimic+AZD4547组FGFR1、p-ERK1/2/ERK1/2、SOX2蛋白相对表达量较miR-133b mimic组降低(P<0.05)。结论miR-133b过表达可能通过抑制FGFR1-ERK1/2-SOX2轴,抑制裸鼠肺癌NCI-H1975细胞移植瘤生长。

miRNA-126调控自噬减轻高糖诱导血管内皮细胞损伤的作用机制

目的探讨miRNA-126对高糖诱导的内皮细胞自噬与凋亡的影响及分子机制。方法采用高糖(HG)诱导HUVECs模型,随机分为4组,即正常葡萄糖(5.5 mmo/L)对照组,HG模型组,miRNA-126-5p mimics组(转染miRNA-126-5p mmics组),miRNA-126-5p inhibitor组(转染miRNA-126 inhibitor组)。HG模型组即终浓度为33.3 mmol/L的葡萄糖诱导24 h,miRNA-126-5p mimics组是miRNA-126-5p mimics转染至HUVECs细胞,48 h后在培养基中加入33.3 mmol/L(终浓度)葡萄糖,培养24 h。miRNA-126-5p inhibitor组是miRNA-126-5p inhibitor转染至HUVECs细胞,48 h后在培养基中加入33.3 mmol/L(终浓度)的葡萄糖,培养24 h。再利用miRNA-126-5p mimics组模型,分别予自噬抑制剂3-甲基腺嘌呤(3-methyl adenine,3-MA)5 mmol/L、ERK通路抑制剂(U-0126)10 mmol/L干预24 h。RT-qPCR检测细胞中miRNA-126-5p的表达水平,CCK-8检测细胞活性,划痕实验检测细胞迁移能力,Westernblot检测细胞培养液中血管内皮生长因子(VEGF)和肝细胞生长因子(HGF),p-ERK、ERK蛋白,p-AKT、AKT蛋白,Bax、Bcl-2蛋白,cleaved-caspase-3蛋白,Beclin-1和Lc3蛋白含量。结果与正常组比较,HG模型细胞中miRNA-126水平,p-ERK/ERK蛋白水平低于正常对照组(P<0.05);与HG模型组相比较,miRNA-126-5p mimics组细胞中miRNA-126、p-ERK/ERK蛋白表达明显升高(P<0.01),细胞中Bax/Bcl-2蛋白,cleaved caspase-3蛋白表达下降(P<0.05),Beclin-1和Lc3蛋白的表达水平升高(P<0.01),细胞活性增强(P<0.01),细胞迁移率提高(P<0.01),VEGF水平升高(P<0.05);与miRNA-126-5p inhibitor组比较,miRNA-126-5p mimics组细胞中miRNA-126、pERK/ERK蛋白表达升高(P<0.01),细胞中Bax/Bcl-2蛋白,cleaved caspase-3蛋白表达下降(P<0.05),Beclin-1和Lc3蛋白表达水平升高(P<0.01),细胞活性增强(P<0.05),细胞迁移率提高(P<0.05),VEGF水平升高(P<0.01);在miRNA-126-5p mimics组中加入3-MA后凋亡蛋白表达明显下降(P<0.01),加入ERK抑制剂后,自噬蛋白表达明显下降(P<0.01)。结论miRNA-126可通过激活ERK信号通路促进细胞的自噬并抑制细胞凋亡,减轻HG诱导的内皮细胞损伤。

Neuroprotective effects of cold-inducible RNA-binding protein during mild hypothermia on traumatic brain injury

Cold-inducible RNA-binding protein（CIRP）, a key regulatory protein, could be facilitated by mild hypothermia in the brain, heart and liver. This study observed the effects of mild hypothermia at 31 ± 0.5℃ on traumatic brain injury in rats. Results demonstrated that mild hypothermia suppressed apoptosis in the cortex, hippocampus and hypothalamus, facilitated CIRP m RNA and protein expression in these regions, especially in the hypothalamus. The anti-apoptotic effect of mild hypothermia disappeared after CIRP silencing. There was no correlation between mitogen-activated extracellular signal-regulated kinase activation and CIRP silencing. CIRP silencing inhibited extracellular signal-regulated kinase-1/2 activation. These indicate that CIRP inhibits apoptosis by affecting extracellular signal-regulated kinase-1/2 activation, and exerts a neuroprotective effect during mild hypothermia for traumatic brain injury.