Thioridazine reverses trastuzumab resistance in gastric cancer by inhibiting S-phase kinase associated protein 2-mediated aerobic glycolysis

BACKGROUND Trastuzumab constitutes the fundamental component of initial therapy for patients with advanced human epidermal growth factor receptor 2(HER-2)-positive gastric cancer(GC).However,the efficacy of this treatment is hindered by substantial challenges associated with both primary and acquired drug resistance.While S-phase kinase associated protein 2(Skp2)overexpression has been implicated in the malignant progression of GC,its role in regulating trastuzumab resistance in this context remains uncertain.Despite the numerous studies investigating Skp2 inhibitors among small molecule compounds and natural products,there has been a lack of successful commercialization of drugs specifically targeting Skp2.AIM To discover a Skp2 blocker among currently available medications and develop a therapeutic strategy for HER2-positive GC patients who have experienced progression following trastuzumab-based treatment.METHODS Skp2 exogenous overexpression plasmids and small interfering RNA vectors were utilized to investigate the correlation between Skp2 expression and trastuzumab resistance in GC cells.Q-PCR,western blot,and immunohistochemical analyses were conducted to evaluate the regulatory effect of thioridazine on Skp2 expression.A cell counting kit-8 assay,flow cytometry,a amplex red glucose/glucose oxidase assay kit,and a lactate assay kit were utilized to measure the proliferation,apoptosis,and glycolytic activity of GC cells in vitro.A xenograft model established with human GC in nude mice was used to assess thioridazine's effectiveness in vivo.RESULTS The expression of Skp2 exhibited a negative correlation with the sensitivity of HER2-positive GC cells to trastuzumab.Thioridazine demonstrated the ability to directly bind to Skp2,resulting in a reduction in Skp2 expression at both the transcriptional and translational levels.Moreover,thioridazine effectively inhibited cell proliferation,exhibited antiapoptotic properties,and decreased the glucose uptake rate and lactate production by suppressing Skp2/protein kinase B/mammalian target of rapamycin/glucose transporter type 1 signaling pathways.The combination of thioridazine with either trastuzumab or lapatinib exhibited a more pronounced anticancer effect in vivo,surpassing the efficacy of either monotherapy.CONCLUSION Thioridazine demonstrates promising outcomes in preclinical GC models and offers a novel therapeutic approach for addressing trastuzumab resistance,particularly when used in conjunction with lapatinib.This compound has potential benefits for patients with Skp2-proficient tumors.

Cyclic nucleotide phosphodiesterase 3B is connected to osteopontin and protein kinase CK2 in pancreatic <i>β</i>-cells

Islets from RIP-PDE3B mice, exhibiting β-cell specific overexpression of the cAMP/cGMP-degrading enzyme phosphodiesterase 3B (PDE3B) and dysregulated insulin secretion, were subjected to microarray analysis. We show that osteopontin (OPN) mRNA is increased in a dose-dependent manner in islets from RIP-PDE3B mice, as compared to wild-type islets. In addition, in silico analysis shows that PDE3B and OPN are interacting. Furthermore, OPN interacts with protein kinase CK2 ina distinct submodule of the protein-protein interaction network. We studied PDE3B and OPN proteins and, in some cases, also PDE1B and PDE4C, under conditions of relevance for insulin secretion. In the presence of forskolin, PDE inhibitors, insulin, or a protein kinase CK2 inhibitor, similar alterations in protein levels of PDE3B and OPN are shown. In summary, results from using a number of strategies demonstrate a connection between PDE3B and OPNas well as a role for protein kinase CK2 inpancreatic β-cells.

Protein kinase CK2 in the ER stress response

The endoplasmic reticulum is the central organelle within a eukaryotic cell where newly synthesized proteins are processed and properly folded. An excess of unfolded or mis-folded proteins induces ER stress signalling pathways. Usually this means a pro-survival strategy for the cell, whereas under extended stress conditions the ER stress signalling pathways have a pro-apoptotic function. CK2 plays a key role in the regulation of the pro-survival as well as the proapoptotic ER stress signalling by directly modulating the activities of members of the ER stress signalling pathways by phosphorylation, regulating the expression of the key factors of the signalling pathways or binding to regulator proteins. The present review will summarize the state of the art in this new emerging field.

多巴丝肼、普拉克索联合治疗帕金森病的效果及对PARK2、CKMT1A、Netrin-1的影响

目的探究多巴丝肼、普拉克索联合治疗帕金森病(PD)的效果及对人帕金森病蛋白2(PARK2)、线粒体肌酸激酶1A(CKMT1A)及神经轴突导向因子1(Netrin-1)的影响。方法选择2021年7月至2023年6月于新乡医学院第一附属医院治疗的PD患者108例为研究对象,依据随机数字表法分为试验组和对照组,每组54例。对照组行多巴丝肼治疗,试验组行多巴丝肼、普拉克索联合治疗。观察两组治疗前后PD严重程度,认知功能水平,睡眠障碍情况,血清PARK2、CKMT1A、Netrin-1水平和不良反应。结果治疗后,试验组统一PD评定量表(UPDRS)各分项得分及总分、匹兹堡睡眠质量指数量表(PSQI)评分均低于对照组(P<0.05),简易智力状态检查量表(MMSE)评分高于对照组(P<0.05)。试验组血清PARK2、Netrin-1水平均高于对照组(P<0.05),血清CKMT1A水平低于对照组(P<0.05)。试验组总有效率大于对照组(P<0.05)。两组不良反应发生率差异无统计学意义(P>0.05)。结论多巴丝肼、普拉克索联合治疗PD可缓解患者症状,提高其认知功能及睡眠质量,改善血清PARK2、CKMT1A、Netrin-1水平。

CKMT1A、CRABP2、PAX8在子宫内膜癌患者血清中的表达水平及其与临床病理参数和预后的关系

目的探讨线粒体肌酸激酶1A(CKMT1A)、细胞视黄酸结合蛋白2(CRABP2)、配对盒基因8(PAX8)在子宫内膜癌患者血清中的表达水平及其与临床病理参数和预后的关系。方法选取2021年5月至2022年5月唐山市妇幼保健院收治的107例子宫内膜癌患者作为研究组。并在治疗后进行1年定期随访,根据患者复发情况分为复发组和未复发组。另选取同时期在该院进行体检的86例健康者作为健康组。采用酶联免疫吸附试验检测各组血清CKMT1A、CRABP2、PAX8水平,比较不同临床病理指标的子宫内膜癌患者血清CKMT1A、CRABP2、PAX8水平。采用Pearson相关分析子宫内膜癌患者血清CKMT1A、CRABP2、PAX8水平的相关性。绘制受试者工作特征(ROC)曲线分析血清CKMT1A、CRABP2、PAX8单独及三者联合检测对子宫内膜癌复发的预测价值。结果研究组血清CKMT1A、CRABP2、PAX8水平均高于健康组,差异均有统计学意义(P<0.05)。Pearson相关分析结果显示,血清CKMT1A与CRABP2水平呈正相关(r=0.437,P<0.001),CKMT1A与PAX8水平呈正相关(r=0.526,P<0.001),CRABP2与PAX8水平呈正相关(r=0.493,P<0.001)。不同肌层浸润、分化程度、淋巴结转移情况等的子宫内膜癌患者血清CKMT1A、CRABP2、PAX8水平比较,差异均有统计学意义(P<0.05),且血清CKMT1A、CRABP2、PAX8水平随着分化程度的降低及淋巴结的转移而升高(P<0.05)。复发组纳入12例患者,非复发组纳入95例患者。复发组血清CKMT1A、CRABP2、PAX8水平均高于非复发组,差异均有统计学意义(P<0.05)。ROC曲线分析结果显示,血清CKMT1A、CRABP2和PAX8单独预测子宫内膜癌复发的曲线下面积分别为0.886、0.850、0.811,均低于三者联合检测的0.978(Z三者联合-CKMT1A=2.318,P=0.020;Z三者联合-CRABP2=2.030,P=0.042;Z三者联合-PAX8=2.955,P=0.003)。结论子宫内膜癌患者血清CKMT1A、CRABP2和PAX8水平均高表达,三者表达与病理类型、分化程度、淋巴结转移情况等临床病理参数以及预后有关,可以作为评估子宫内膜癌患者预后的生物学指标。

特发性膜性肾病患者血清ROCK2、renalase水平及其诊断价值

目的探讨Rho相关卷曲螺旋形成蛋白激酶2(ROCK2)、肾胺酶(renalase)在特发性膜性肾病(IMN)患者血清中的表达变化及其对IMN的诊断价值。方法选取2019年1月—2020年11月河北以岭医院肾病科收治IMN患者120例为IMN组,另选取同期医院进行健康体检的志愿者120例为健康对照组。酶联免疫吸附法(ELISA)检测受试者血清ROCK2、renalase水平,Pearson法分析ROCK2、renalase水平与部分临床指标的相关性;采用受试者工作特征(ROC)曲线分析血清ROCK2、renalase及二者联合诊断IMN的价值。结果IMN组ROCK2、renalase水平均显著高于健康对照组(t/P=12.837/<0.001、11.066/<0.001)。Ⅰ期、Ⅱ期、Ⅲ期、Ⅳ期IMN患者血清ROCK2逐次升高(F/P=77.154/<0.001),而Ⅰ期、Ⅱ期、Ⅲ期血清renalase水平逐次升高,但Ⅳ期血清renalase水平低于Ⅲ期(F/P=163.042/<0.001)。Alb与血清ROCK2、renalase水平呈负相关(r/P=-0.302/0.009、-0.402/<0.001),PLA2R抗体、BUN、SCr、24 h尿蛋白与血清ROCK2、renalase水平均呈正相关(r/P=0.336/<0.001、0.264/0.011、0.315/0.007、0.320/<0.001,0.359/<0.001、0.284/0.010、0.420/<0.001、0.412/<0.001);ROC曲线显示:血清ROCK2、renalase及二者联合诊断IMN的AUC分别为0.908、0.907、0.965,二者联合优于各自单独预测效能(Z=3.597,3.755,P均<0.001)。结论ROCK2与renalase在IMN患者血清中均高表达,二者联合诊断IMN的价值较高。

miR-192-5p靶向CKIP-1促进骨质疏松患者骨髓间充质干细胞成骨分化

背景:酪蛋白激酶2结合蛋白1(casein kinase 2-interaction protein-1,CKIP-1)是一种重要的骨形成负调控基因,其敲除鼠骨质显著增强、骨形成和骨密度也显著提高。而miRNA作为较早发现的小分子调控物,对大多数编码基因具有调控作用,在成骨分化中发挥重要作用。目的:探讨miRNA/CKIP-1对骨质疏松患者骨髓间充质干细胞成骨分化的影响及其分子机制。方法:采用miRNA-Seq技术检测2022年3-6月在开封市中心医院骨外科就诊32例骨质疏松患者及同期体检中心健康人群骨髓间充质干细胞中miRNA的变化情况;利用Targetscan网站预测靶向调控CKIP-1的miRNA,利用荧光素酶报告基因实验检测miRNA与CKIP-1启动子区DNA的结合;在骨髓间充质干细胞中转染miR-192-5p类似物(miR-192-5p mimics)/阴性对照(NC mimics)或miR-192-5p抑制剂(miR-192-5p inhibitor)/阴性对照(NC inhibitor),成骨诱导后第7,14天,通过实时荧光定量PCR技术及茜素红染色检测成骨标志基因Runt相关转录因子2(Runx2)、骨钙素、抗骨桥蛋白、骨唾液蛋白及CKIP-1的表达水平和骨髓间充质干细胞向成骨细胞分化的情况;采用蛋白质免疫印迹实验及茜素红染色检测miR-192-5p/CKIP-1/轴对细胞成骨分化的的调控作用。结果与结论:与健康组相比,骨质疏松组有16个miRNA表达明显升高,53个miRNA表达明显降低(P<0.05);利用Targetscan网站预测,并通过荧光素酶报告基因实验验证,发现miR-192-5p与CKIP-1有互补的核苷酸序列(P<0.05);过表达miR-192-5p,Runx2、骨钙素、骨桥素和骨唾液蛋白的表达水平显著升高(P<0.05),抑制miR-192-5p,Runx2、骨钙素、骨桥素和骨唾液蛋白的表达水平显著降低(P<0.05),而沉默CKIP-1的表达后,Runx2、骨钙素及骨桥素的蛋白水平增加(P<0.05),逆转了敲低miR-192-5p对细胞成骨分化的抑制作用。上述结果证实,miR-192-5p在骨质疏松症中表达降低;miR-192-5p通过靶向抑制CKIP-1的表达,促进骨髓间充质干细胞成骨分化。

ROCK2和KLF6在急性缺血性脑卒中的表达变化及其与病情程度和预后的相关性

目的探究Rho相关蛋白激酶2(ROCK2)和Krüppel样因子6(KLF6)在急性缺血性脑卒中(AIS)患者血清表达变化及其与病情程度和预后的相关性。方法选取2021年1月至2023年3月在我院确诊的117例AIS患者作为研究组,另选120例在我院同期体检健康者作为对照组。根据美国国立卫生院神经功能缺损(NIHSS)评分,将患者分为轻度(46例)、中度(40例)、重度(31例)组。根据改良Rankin量表将患者分为预后良好(74例)和预后不良(43例)组。酶联免疫吸附试验测定血清ROCK2和KLF6水平。Spearman分析ROCK2和KLF6水平与NIHSS评分的关系;多因素Logistic回归分析AIS患者预后不良的危险因素;受试者工作特征(ROC)曲线分析血清ROCK2和KLF6水平对AIS患者预后不良的预测价值。结果与对照组相比,研究组ROCK2和KLF6水平显著增加(P<0.05)。与轻度组相比,中度组和重度组ROCK2和KLF6水平及NIHSS评分显著增加(P<0.05),与中度组相比,重度组ROCK2和KLF6水平及NIHSS评分显著增加(P<0.05)。相关性分析结果显示,ROCK2和KLF6水平与NIHSS评分均呈正相关(r=0.605,0.632,P<0.001)。与预后良好组相比,预后不良组患者ROCK2和KLF6水平显著增加(P<0.05)。ROCK2、KLF6单独及联合预测AIS患者预后不良的曲线下面积(AUC)分别为0.886(95%CI 0.822~0.949)、0.850(95%CI 0.770~0.930)、0.954(95%CI 0.919~0.988)。预后良好组与预后不良组患者总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)水平及NIHSS评分比较差异具有统计学意义(P<0.05)。多因素Logistic回归分析结果显示TG水平、NIHSS评分、ROCK2和KLF6是AIS患者预后不良的独立危险因素(P<0.05)。结论AIS患者ROCK2和KLF6表达上调,其水平与病情程度及预后不良密切相关。

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.

AIM2,ROCK1在老年急性冠状动脉综合征患者中的表达及诊断、预后价值

目的探讨黑素瘤缺乏因子2(melanoma deficiency factor 2,AIM2)和Rho关联含卷曲螺旋蛋白激酶1(Rho associated coiled coil containing protein kinase 1,ROCK1)在老年急性冠状动脉综合征(acute coronary syn⁃drome,ACS)患者中的表达及诊断、预后价值。方法选取2019年12月至2022年12月海军军医大学第一附属医院95例老年ACS患者为ACS组,同期选取健康体检志愿者95名作为对照组。然后对老年ACS患者预后随访6个月,根据主要不良心血管事件(major adverse cardiac events,MACE)发生情况将其分为MACE组28例和未发生MACE组67例。采用酶联免疫吸附法(enzyme-linked immunosorbent assay,ELISA)检测AIM2和ROCK1的表达情况;多因素Logistic回归分析老年ACS患者发生MACE的影响因素;采用受试者工作特征曲线(receiver operating characteristic curve,ROC)分析AIM2、ROCK1对ACS的诊断效能及发生MACE的预测价值。结果与对照组相比,ACS组患者血清AIM2、ROCK1浓度均显著升高,差异有统计学意义(P<0.05)。血清AIM2、ROCK1浓度二者联合诊断ACS的曲线下面积(area under the curve,AUC)最高,优于血清AIM2、ROCK1各自单独诊断(Z二者联合-AIM2=3.308、P<0.001,Z二者联合-ROCK1=4.336、P<0.001)。与未发生MACE组相比,MACE组血清AIM2、ROCK1血清浓度高,且差异有统计学意义(P<0.05);有高血压史患者比例较高,差异有统计学意义(P<0.05)。根据多因素Logistic回归分析结果可以发现,AIM2、ROCK1、高血压史是影响MACE发生的危险因素(P<0.05)。血清AIM2、ROCK1二者联合预测发生MACE的AUC最高,优于血清AIM2、ROCK1各自单独预测(Z二者联合-AIM2=2.828、P=0.005,Z二者联合-ROCK1=2.072、P=0.038)。结论AIM2和ROCK1在老年ACS患者血清中呈高表达状态,且与患者发生MACE密切相关,通过检测AIM2和ROCK1的表达情况可能有助于早期诊断和评估老年ACS患者的预后。

Ca2+/calmodulin-dependent protein kinase II regulates colon cancer proliferation and migration via ERK1/2 and p38 pathways

AIM To investigate the role of calmodulin-dependent protein kinase Ⅱ(Ca MKⅡ) in colon cancer growth,migration and invasion.METHODS Ca MKⅡ expression in colon cancer and paracancerous tissues was evaluated via immunochemistry. Transcriptional and posttranscriptional levels of Ca MKⅡin tissue samples and MMP2,MMP9 and TIMP-1 expression in the human colon cancer cell line HCT116 were assessed by q RTPCR and western blot. Cell proliferation was detected with the MTT assay. Cancer cell migration and invasion were investigated with the Transwell culture system and woundhealing assay.RESULTS We first demonstrated that CaMK Ⅱ was ove rexpressed in human colon cancers and was associated with cancer differentiation. In the human colon cancer cell line HCT116,the Ca MKII-specific inhibitor KN93,but not its inactive analogue KN92,decreased cancer cell proliferation. Furthermore,KN93 also significantly prohibited HCT116 cell migration and invasion. The specific inhibition of ERK1/2 or p38 decreased the proliferation and migration of colon cancer cells.CONCLUSION Our findings highlight Ca MKⅡ as a potential critical mediator in human colon tumor development and metastasis.

Bcl-2 over-expression and activation of protein kinase C suppress the Trail-induced apoptosis in Jurkat T cells

Trail, a tumor necrosis factor-related apoptosis-inducing ligand, is a novel potent endogenous activator of the cell death pathway through the activation of cell surface death receptors Trail-R1 and Trail-R2. Its role, like FasL in activation-induced cell death (AICD), has been demonstrated in immune system. However the mechanism of Trail induced apoptosis remains unclear. In this report, the recombinant Trail protein was expressed and purified. The apoptosis-inducing activity and the regulation mechanism of recombinant Trail on Jurkat T cells were explored in vitro. Trypan blue exclusion assay demonstrated that the recombinant Trail protein actively killed Jurkat T cells in a dose-dependent manner. Trail-induced apoptosis in Jurkat T cells were remarkably reduced by Bcl-2 over expression in Bcl-2 gene transfected cells. Treatment with PMA (phorbol 12-myristate 13-acetate), a PKC activator, suppressed Trail-induced apoptosis in Jurkat T cells. The inhibition of apoptosis by PMA was abolished by pretreatment with Bis, a PKC inhibitor. Taken together, it was suggested that Bcl-2 over-expression and PMA activated PKC actively down-regulated the Trail-mediated apoptosis in Jurkat T cell.

Caffeic acid phenethyl ester up-regulates antioxidant levels in hepatic stellate cell line T6 via an Nrf2-mediated mitogen activated protein kinases pathway

AIM To investigate the antioxidant effect of caffeic acid phenethyl ester (CAPE) in hepatic stellate cell-T6 (HSC-T6) cells cultured in vitro and the potential mechanisms. METHODS HSC-T6 cells were cultured in vitro and treated with various concentrations of CAPE for 24, 48 and 72 h, respectively. Cell proliferation was investigated using the MTT assay, and cell ultrastructural alterations were observed by transmission electron microscopy. Flow cytometry was employed to investigate the effects of CAPE on apoptosis and the levels of reactive oxygen species in HSC-T6 cells cultured in vitro. An enzyme immunoassay instrument was used to evaluate antioxidant enzyme expression. The effect on alpha-smooth muscle actin was shown using immunofluorescence. Gene and protein levels of Nrf2, related factors, and mitogen activated protein kinases (MAPKs), in HSC-T6 cells were detected using RT-PCR and Western blot, respectively. RESULTS CAPE inhibited the proliferation and activation of HSC-T6 cells cultured in vitro. CAPE increased the antioxidant levels and the translocation of Nrf2 from the cytoplasm to the nucleus in HSC-T6 cells. Moreover, the phosphorylation of MAPKs in cells decreased in response to CAPE. Interestingly, CAPE-induced oxidative stress in the cells was significantly attenuated by pretreatment with MAPKs inhibitors. CONCLUSION CAPE inhibits cell proliferation and up-regulates the antioxidant levels in HSC-T6 cells partly through the Nrf2-MAPKs signaling pathway.

Inhibition of DNA-dependent Protein Kinase Catalytic Subunit by Small Molecule Inhibitor NU7026 Sensitizes Human Leukemic K562 Cells to Benzene Metabolite-induced Apoptosis

Benzene is an established leukotoxin and leukemogen in humans. We have previously re- ported that exposure of workers to benzene and to benzene metabolite hydroquinone in cultured cells induced DNA-dependent protein kinase catalytic subunit （DNA-PKcs） to mediate the cellular response to DNA double strand break （DSB） caused by DNA-damaging metabolites. In this study, we used a new, small molecule, a selective inhibitor of DNA-PKcs, 2-（morpholin-4-yl）-benzo[h]chomen-4-one （NU7026）, as a probe to analyze the molecular events and pathways in hydroquinone-induced DNA DSB repair and apoptosis. Inhibition of DNA-PKcs by NU7026 markedly potentiated the apoptotic and growth inhibitory effects of hydroquinone in proerythroid leukemic K562 cells in a dose-dependent manner. Treatment with NU7026 did not alter the production of reactive oxygen species and oxidative stress by hydroquinone but repressed the protein level of DNA-PKcs and blocked the induction of the kinase mRNA and protein expression by hydroquinone. Moreover, hydroquinone increased the phos- phorylation of Akt to activate Akt, whereas co-treatment with NU7026 prevented the activation of Akt by hydroquinone. Lastly, hydroquinone and NU7026 exhibited synergistic effects on promoting apop- tosis by increasing the protein levels of pro-apoptotic proteins Bax and caspase-3 but decreasing the protein expression of anti-apoptotic protein Bcl-2. Taken together, the findings reveal a central role of DNA-PKcs in hydroquinone-induced hematotoxicity in which it coordinates DNA DSB repair, cell cycle progression, and apoptosis to regulate the response to hydroquinone-induced DNA damage.

Chronic stress causes protein kinase C epsilon-aldehyde dehydrogenase 2 signaling pathway perturbation in the rat hippocampus and prefrontal cortex,but not in the myocardium

Chronic stress is strongly associated with the occurrence and development of depression and cardiovascular disease.Stress can induce altered mitochondrial function and activation of apoptosis in the cardio-cerebral system.However,it is unknown whether the protein kinase C ε（PKCε）-aldehyde dehydrogenase 2（ALDH2） pathway is altered under chronic stress,and this study sought to address this question.A rat model of depression was established using a chronic unpredictable mild stress（CUMS） protocol.After experiencing CUMS for 4 weeks,the sucrose preference test and the forced swim test verified depressive-like behaviors.Enzyme linked immunosorbent assays showed that ALDH2 activity was decreased in the rat hippocampus and prefrontal cortex,but was not altered in the myocardium.Western blot assays demonstrated reduced levels of ALDH2 and PKCε,but increased levels of 4-hydroxy-2-nonenal（4 HNE） adducts.Caspase-3 expression did not obviously alter,but active forms of caspase-3 were increased in the hippocampus and prefrontal cortex.In the myocardium,expression of ALDH2,PKCε and 4 HNE adducts did not remarkably alter;while caspase-3 expression was reduced and the active forms of caspase-3 were upregulated.Pearson＇s correlation test demonstrated that expression of 4 HNE adducts was positively correlated with levels of the active forms of caspase-3 in the hippocampus and prefrontal cortex,but not in the myocardium.In conclusion,chronic stress can damage the PKCε-ALDH2 signaling pathway in the hippocampus and prefrontal cortex,but not in the myocardium.Moreover,4 HNE is associated with active forms of caspase-3 in the hippocampus and prefrontal cortex.

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.

Increased endothelin receptor B and G protein coupled kinase-2 in the mesentery of portal hypertensive rats

AIM: To elucidate the mechanisms of mesenteric vasodilation in portal hypertension (PHT), with a focus on endothelin signaling. METHODS: PHT was induced in rats by common bile duct ligation (CBDL). Portal pressure (PP) was measured directly via catheters placed in the portal vein tract. The level of endothelin-1 (ET-1) in the mesenteric circulation was determined by radioimmunoassay, and the expression of the endothelin A receptor (ETAR) and endothelin B receptor (ETBR) was assessed by immunofluorescence and Western blot. Additionally, expression of G protein coupled kinase-2 (GRK2) and β-arrestin 2, which influence endothelin receptor sensitivity, were also studied by Western blot. RESULTS: PP of CBDL rats increased significantly (11.89 ± 1.38 mmHg vs 16.34 ± 1.63 mmHg). ET-1 expression decreased in the mesenteric circulation 2 and 4 wk after CBDL. ET-1 levels in the systemic circulation of CBDL rats were increased at 2 wk and decreased at 4 wk. There was no change in ETAR expression in response to CBDL; however, increased expression of ETBR in the endothelial cells of mesenteric arterioles and capillaries was observed. In sham-operated rats, ETBR was mainly expressed in the CD31+ endothelial cells of the arterioles. With development of PHT, in addition to the endothelial cells, ETBR expression was noticeably detectable in the SMA+ smooth muscle cells of arterioles and in the CD31+ capillaries. Following CBDL, increased expression of GRK2 was also found in mesenteric tissue, though there was no change in the level of β-arrestin 2. CONCLUSION: Decreased levels of ET-1 and increased ETBR expression in the mesenteric circulation following CBDL in rats may underlie mesenteric vasodilation in individuals with PHT. Mechanistically, increased GRK2 expression may lead to desensitization of ETAR, as well as other vasoconstrictors, promoting this vasodilatory effect.

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.

Role of Protein Kinase C in the Activation of Store-operated Ca^(2+) Entry in Airway Smooth Muscle Cells

Store-operated Ca2＋ channels （SOCs） are plasma membrane Ca2＋ permeable channels activated by depletion of intracellular Ca2＋ store. Ca2＋ entry through SOCs is known as store-operated Ca2＋ entry （SOCE）, which plays an important role in the functional regulation of airway smooth muscle cells （ASMCs）. Protein kinase C （PKC） has been shown to have an activating or inhibiting effect on SOCE, depending on cell types and PKC isoforms that are involved. In ASMCs, the effect of PKC on SOCE has not been elucidated so far. In this study, the role of PKC in the activation of SOCE in rat ASMCs was examined by using Ca2＋ fluorescence imaging technique. The results showed that acute application of PKC activators PMA and PDBu did not affect SOCE induced by the sarcoplasmic reticulum Ca2＋-ATPase （SERCA） inhibitor thapsigargin. The non-selective PKC inhibitor chelerythrine significantly inhibited thapsigargin- and bradykinin-induced SOCE. RT-PCR assay identified PKCα, δ and ε isoforms in rat ASMCs. PKCα-selective inhibitor G6976 and PKCε-inhibiting peptide Epsilon-V1-2 had no effect on SOCE; by contrast, PKCδ-selective inhibitor rottlerin attenuated SOCE dramatically, suggesting that PKCδ was the major PKC isoform involved in the activation of SOCE in ASMCs. Moreover, PKC down-regulation by extended exposure to high doses of PMA or PDBu also reduced SOCE, confirming the essential role of PKC in the activation of SOCE in ASMCs. In addition, PKC down-regulation did not influence the expression of stromal interaction molecule 1 （STIM1） and Orai1, two elementary molecules in the regulation and activation of SOCs. These results identified PKCδ as an essential PKC isoform involved in the activation of SOCE, and confirmed that PKC regulates the function of ASMCs in a SOCE-dependent manner.

Specific effects of c-Jun NH2-terminal kinaseinteracting protein 1 in neuronal axons

c-Jun NH2-terminal kinase（JNK）-interacting protein 3 plays an important role in brain-derived neurotrophic factor/tropomyosin-related kinase B（Trk B） anterograde axonal transport. It remains unclear whether JNK-interacting protein 1 mediates similar effects, or whether JNK-interacting protein 1 affects the regulation of Trk B anterograde axonal transport. In this study, we isolated rat embryonic hippocampus and cultured hippocampal neurons in vitro. Coimmunoprecipitation results demonstrated that JNK-interacting protein 1 formed Trk B complexes in vitro and in vivo. Immunocytochemistry results showed that when JNK-interacting protein 1 was highly expressed, the distribution of Trk B gradually increased in axon terminals. However, the distribution of Trk B reduced in axon terminals after knocking out JNK-interacting protein 1. In addition, there were differences in distribution of Trk B after JNK-interacting protein 1 was knocked out compared with not. However, knockout of JNK-interacting protein 1 did not affect the distribution of Trk B in dendrites. These findings confirm that JNK-interacting protein 1 can interact with Trk B in neuronal cells, and can regulate the transport of Trk B in axons, but not in dendrites.