Distinct signaling pathways confer different vascular responses to VEGF 121 and VEGF 165

Vascular endothelial growth factor (VEGF) is a pleiotropic factor that regulates embryonal vasculogenesis, tumor angiogenesis and vascular permeability. Among eight differential isoforms, VEGF 121 mainly regulates vascular permeability, while VEGF 165 induces angiogenesis. Our previous studies have suggested that VEGF 121 and VEGF 165 are mainly detected in the lesions of psoriasis and atopic dermatitis, especially VEGF 121. VEGF 121 is the most predominant isoform, which plays a major role in the increased vascular permeability in the aforementioned skin lesions. Thus, the differential expression of VEGF isoforms may be critical in determining either an angiogenic or a hyper-permeable state. However, the distinct VEGF signaling pathways that induce angiogenesis and vascular hyper-permeability in endothelial cells have never been demonstrated. To clarify the differential effects elicited by VEGF 121 and VEGF 165, we compared the biological responses and the signaling pathways activated by VEGF 121 and VEGF 165 in human umbilical vein endothelial cells (HUVEC). VEGF 165 significantly increased the level of phosphorylation in the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway, whereas VEGF 121 had little to no effect. In contrast, VEGF 121 induced rapid activation of the Src pathway, while VEGF 165 showed a less pronounced and delayed activation of the Src pathway. Furthermore, the VEGF-induced hyper-permeability and cell proliferation of HUVEC were inhibited by a Src inhibitor (PP2) and a MEK inhibitor (PD98059), respectively. These results indicate that distinct signaling pathways confer different vascular responses to VEGF 121 and VEGF 165.     

Multiple proliferation signaling pathways are modulated by octacalcium phosphate in osteoblasts

Octacalcium phosphate (OCP), a type of bioactive ceramics, may be associated with dentine, tooth apatite, and especially bone generation, and promotes wound healing after fracture. Recently, commercial bone grafting products containing a large amount of OCP material have been released because OCP can be synthesized in large quantities. It is reported to increase cell proliferation, but the interaction between OCP and cell signaling pathways is still unclear. In this study, first, we demonstrated OCP mediated cell signaling pathways with only purified OCP materials. OCP regulated P38, JNK (c-Jun N-terminal kinase), Src, and AKT (protein kinase B) signaling pathways. OCP crystals appeared in the characteristic ribbon shape but varied by several tens of micrometers in size. The X-ray diffraction pattern was the same as previously reported. We studied two concentrations of OCP (10 mg/ml and 20 mg/ml) to understand whether the effect of OCP on cell signaling pathways is dose dependent. We confirmed that OCP treatment affected cell proliferation and alkaline phosphatase and disrupted Src phosphorylation but did not change the total protein level. P38 phosphorylation was activated with OCP treatment and inhibited by SB203580, but P38 total protein level did not change. OCP inhibited JNK phosphorylation signaling, whereas PD98509 inhibited JNK phosphorylation with or without OCP. Interestingly, the AKT total level decreased after OCP treatment, but AKT phosphorylation increased considerably. Our results demonstrate that OCP materials modulate cell signaling pathways and increase cell proliferation.     

PM2.5通过p38 MAPK信号通路影响血管平滑肌细胞增殖和迁移

目的:研究细颗粒物(PM2.5)对血管平滑肌细胞增殖和迁移的影响,以及p38 MAPK信号通路在其中的作用。方法:体外培养人血管平滑肌细胞,分为对照组和不同浓度PM2.5染毒组,分别用PBS及6.25、12.5和25 mg/L的PM2.5作用于细胞,用CCK-8法和EdU染色法检测细胞增殖能力的变化,用划痕实验和Transwell法检测细胞的迁移能力,然后根据结果选取PM2.5最强作用浓度染毒细胞,在不同时点用Western blot法检测p38MAPK信号分子的磷酸化改变,并观察用特异性抑制剂阻断p38 MAPK信号后细胞在PM2.5刺激下的增殖和迁移情况。结果:与对照组比较,PM2.5染毒可明显促进血管平滑肌细胞的增殖和迁移能力,在设定的浓度范围内以12.5 mg/L浓度组的作用最为明显(P<0.05)。Western blot结果显示,12.5 mg/L PM2.5染毒可上调血管平滑肌细胞p38 MAPK的磷酸化水平;而加入p38 MAPK抑制剂SB203580预处理后,PM2.5诱导的细胞增殖和迁移明显受到抑制,说明p38 MAPK可能介导PM2.5的毒性作用。结论:PM...     

虫草素通过ERK1/2、Ezrin和Akt信号通路抑制胆囊癌细胞SNU-308的增殖和迁移

目的:探讨虫草素对胆囊癌细胞SNU-308增殖和迁移的影响及其分子机制。方法:MTT法和平板集落形成实验检测不同浓度虫草素对胆囊癌SNU-308细胞活力和集落形成能力的影响;Annexin V/PI双染法检测细胞凋亡率;Western blot法检测细胞凋亡和自噬相关蛋白以及Akt、ERK1/2和Ezrin蛋白的磷酸化水平;免疫荧光染色法检测细胞内LC3的表达水平;划痕愈合实验和Transwell实验检测虫草素对胆囊癌细胞迁移能力的影响;划痕实验检测Akt抑制剂和ERK1/2抑制剂及Ezrin基因沉默对细胞迁移能力的影响。结果:虫草素可显著抑制胆囊癌细胞的活力和集落形成能力(P0.05)。流式细胞术结果显示,虫草素可诱导胆囊癌细胞凋亡(P0.05)。Western blot结果显示,虫草素处理后Bcl-2表达降低,Bax、细胞色素C(Cyto C)、Fas、Fas L和cleaved caspase-3蛋白水平升高,自噬标识蛋白LC3-II/I比例和beclin 1表达上调(P0.05)。免疫荧光染色结果显示,虫草素处理后SNU-308细胞胞浆中LC3荧光颗粒的数量明显增多。划痕实验和Transwell实验结果显示虫草素可抑制细胞迁移(P0.05)。虫草素明显抑制Akt、ERK1/2和Ezrin蛋白的磷酸化水平(P0.05)。Ezrin基因沉默及Akti-1/2和GDC-0994均可抑制胆囊癌细胞的迁移作用(P0.05)。结论:虫草素通过诱导凋亡和自噬抑制胆囊癌细胞的增殖和迁移,其机制可能与调控ERK1/2,Ezrin和Akt信号通路有关。     

Distinct signaling mechanisms activate the target of rapamycin in response to different B-cell stimuli

Phosphoinositide 3-kinase (PI3K) and the mammalian target of rapamycin (mTOR), a downstream kinase, are both required for proliferation of splenic B cells. However, the functions of PI3K and mTOR in response to different stimuli and among B cell subsets have not been fully elucidated. We used flow cytometry and magnetic cell sorting to examine the requirement for PI3K and mTOR in responses of splenic B cell subsets to BCR and LPS stimulation. BCR-mediated phosphorylation of Akt and Erk is sensitive to the PI3K catalytic inhibitor wortmannin in both marginal zone (MZ) and follicular (FO) cells. BCR-mediated mTOR activation in both subsets is inhibited by wortmannin, though less strongly in MZ cells. In contrast, LPS-induced mTOR signaling is strikingly resistant to wortmannin in both subsets. Similarly, functional responses to LPS are partially wortmannin resistant yet sensitive to mTOR inhibition by rapamycin. We also observed mitogen-independent mTOR activity that is regulated by nutrient availability, and is significantly elevated in MZ cells relative to FO cells. These data define both similarities and differences in PI3K/mTOR signaling mechanisms in MZ and FO cells, and suggest that mTOR signaling can occur in the absence of PI3K activation to promote B cell responses to LPS.     

山柰酚-3-O-芸香糖苷对血管平滑肌细胞增殖、迁移及TGFBR1信号通路活化的影响

目的:探索山柰酚-3-O-芸香糖苷(KR)对血管平滑肌细胞(VSMC)增殖、迁移及转化生长因子β受体1(TGFBR1)信号通路活化的影响。方法:将KR(10、20和40μmol/L)孵育大鼠VSMC细胞系A7R5 24 h,或将40μmol/L KR孵育A7 R5细胞24、48和72 h后,MTT法检测细胞活力,Ed U染色检测细胞增殖情况,Transwell小室实验检测细胞迁移能力的变化,Western blot检测细胞迁移相关蛋白基质金属蛋白酶2(MMP2)及基质金属蛋白酶9(MMP9)的表达;分子对接技术探索KR与TGFBR1之间的相互关系,Western blot检测TGFBR1及其下游的Smad2和Smad3的激活情况。结果 :KR剂量和时间依赖性地降低细胞活力,剂量依赖性地减少Ed U染色阳性细胞数量,降低迁移细胞数量,减少迁移相关蛋白MMP2和MMP9的表达(P0.05)。KR与TGFBR1发生分子对接的结合力为-9.804 kcal/mol,与TGBFR1的SER-280、ARG-215、ASP-290和LYS-335氨基酸残基形成氢键连接。KR剂量依赖性地降低TGFBR1及其下游Smad2和Smad3的激活(P0.05)。结论:KR能抑制VSMC的增殖和迁移,其机制可能与抑制TGFBR1信号通路相关。     

叶酸通过下调ERK1/2信号通路抑制血管平滑肌细胞增殖和迁移

目的:探讨叶酸(folic acid,FA)对血管平滑肌细胞(VSMCs)增殖和迁移的影响及其机制。方法:取SD大鼠的主动脉,采用组织贴块法培养VSMCs,随机分组进行实验。采用CCK-8和Ed U法检测叶酸对VSMCs活力和增殖能力的影响。采用划痕实验和Transwell法检测叶酸对VSMCs迁移和侵袭的影响。采用Western blot法检测细胞增殖核抗原(PCNA)蛋白表达以及血小板源性生长因子受体(PDGFR)和细胞外信号调节激酶1/2(ERK1/2)蛋白的磷酸化水平。结果:叶酸抑制血小板源性生长因子(PDGF)诱导的VSMCs的活力,并呈浓度依赖性(P0.05)。叶酸抑制PDGF诱导的VSMCs的迁移,并呈浓度依赖性(P0.05)。叶酸降低PCNA表达和PDGFR磷酸化水平,并抑制PDGF激活的ERK1/2信号通路。结论:叶酸降低PDGF诱导的VSMCs PCNA和p-PDGFR蛋白水平,下调ERK1/2信号通路,从而抑制VSMCs的增殖和迁移。     

Plakophilin-2 accelerates cell proliferation and migration through activating EGFR signaling in lung adenocarcinoma

BackgroundPlakophilin 2 (PKP2), encodes a plakophilin protein that belongs to the member of desmosomal proteins. It has been reported that high expression of PKP2 is associated with several types of cancer in humans. However, the role of PKP2 in lung cancer remains obscure.MethodsPKP2 expression was investigated in non-small cell lung cancer (NSCLC) tissues and non-tumor tissues by performing immunohistochemistry on a tissue microarray and using The Cancer Genome Atlas (TCGA) database. Kaplan-Meier survival analysis and multivariate Cox-regression analysis were performed to identify the clinical significance of PKP2. 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS), colony formation, Transwell and xenograft tumor growth/ metastasis assays were conducted to evaluate the biological function of PKP2 in vitro and in vivo. Gene set enrichment analysis (GSEA), WB and immunoprecipitation (IP) assay were utilized to explore the potential downstream signaling pathway and molecule mechanism of PKP2 in lung adenocarcinoma (LUAD).ResultsAnalysis of PKP2 expression and clinicopathological parameters reveals a significant correlation of PKP2 expression with gender (n = 1020, P < 0.001) and histological type (n = 1020, P < 0.001). Subsequently, our results demonstrated that high PKP2 expression is not associated with poor survival in different gender of lung cancer patients, and is an unfavorable and independent prognostic biomarker for LUAD patients, but not for LUSC patients. Gene set enrichment analysis (GSEA) revealed that PKP2 expression is positively associated with EGFR signaling in LUAD. Further, in vitro and in vivo assays revealed that PKP2 promotes cell proliferation, migration and invasion through activating EGFR signaling pathway in LUAD cells.ConclusionOur study provides the basis for further investigation of the function and molecular mechanism by which upregulation of PKP2 promotes the development and progression of LUAD. PKP2 may serve as a potential target for anticancer therapies.     

体外重组表达血管生长因子VEGF165单克隆抗体的制备及鉴定

目的:研制人VEGF165单克隆抗体(mAb),为研究VEGF165的生物学活性提供基础.方法:应用RT-PCR从脐静脉内皮细胞中克隆人VEGF165基因,克隆人原核表达载体pGEX-6P1中获得重组表达载体pGEX-6P1 -VEGF165,转化大肠杆菌BL21,经IPTG诱导表达获得重组人VEGF165蛋白,将重组蛋白纯化后免疫BALB/c小鼠,通过杂交瘤技术,制备人VEGF165高效价的mAb.通过鸡胚血管形成抑制实验、HUVEC迁移抑制实验以及HUVEC血管形成抑制实验,对获得的人VEGF165特异性mAb进行进一步鉴定.结果:成功地从脐静脉血管内皮细胞中克隆出人VEGF165基因,并在大肠杆菌表达系统中获得高效表达,以纯化重组蛋白作为免疫原免疫小鼠,筛选获得5株分泌人VEGF165特异性mAb的杂交瘤细胞株,分别命名为5A6、3F5、6H3、7D10、7A10,其中5A6、3F5、6H3、7D10分泌的mAb亚类为IgG2a,7A10分泌的mAb亚类为IgG2b,抗体轻链均为κ链.5株mAb均能抑制鸡胚血管形成、抑制HUVEC迁移和及血管形成.结论:所获得的mAb具有效价高,活性强的优点,为抗肿瘤血管研究中进一步研究VEGF165的生物学作用提供了重要的基础.     

27-羟基胆固醇激活LXR信号通路调节肺癌细胞的增殖

目的:探讨胆固醇代谢产物27-羟基胆固醇(27-OHC)对肺癌细胞增殖的影响。方法:采用不同浓度(0、0.3125、0.625、1.25、2.5、5和10μmol/L)的27-OHC处理人肺癌A549细胞24～48 h,随后使用细胞计数试剂盒(CCK-8法)评估细胞活力,采用流式细胞术检测细胞周期,Ed U实验检测细胞增殖状况,采用总胆固醇检测试剂盒检测细胞内胆固醇水平,real-time PCR及Western blot法分别检测胆固醇代谢相关分子的表达。结果:27-OHC以剂量和时间依赖性显著降低A549肺癌细胞的活力(P 0.01),抑制细胞增殖(P 0.05)。27-OHC通过上调肝X受体(LXR)信号通路下游靶蛋白ATP结合盒转运蛋白A1(ABCA1)的表达,促进细胞内胆固醇的外排,同时下调低密度脂蛋白受体(LDLR)和3-羟基-3-甲基戊二酰辅酶A还原酶(HMG-CR)的表达,减少胆固醇的摄入和从头合成,导致细胞内胆固醇水平降低,细胞活力下降(P 0.01)。此外,LXR通路被5μmol/L GSK2033部分阻断后,27-OHC对A549细胞活力的抑制作用显著减弱(P 0.05)。结论:27-OHC通过激活LXR通路抑制A549细胞增殖。     

Growth factor signaling pathways in vascular development and disease

Angiogenic blood vessel growth is essential to ensure organs receive adequate blood supply to support normal organ function and homeostasis. Angiogenesis involves a complex series of cellular events through which new vessels grow out from existing vasculature. Growth factor signaling, layered over a range of other signaling inputs, orchestrates this process. The response of endothelial cells (ECs) to growth factor signals must be carefully controlled through feedback mechanisms to prevent excessive vessel growth, remodeling or destabilization. In this article, we summarize recent findings describing how ECs respond to growth factor signals during blood vessel development and homeostasis and how perturbation of these responses can lead to disease.     

问号钩端螺旋体在体外诱导细胞凋亡及相关信号通路的研究

目的 了解问号钩端螺旋体诱导不同宿主细胞凋亡的作用及相关胞内信号传导通路.方法 建立问号钩体黄疸出血群赖型赖株小鼠单核-巨噬样细胞J774A.1、人脐静脉内皮细胞EVC304和人Ⅱ型肺泡上皮细胞A549感染模型.采用FITC-Annexin V/PI荧光标记流式细胞术检测细胞凋亡或坏死情况.分别采用荧光比色法和Western blot检测感染的J774A.1细胞caspase-3,-8,-9活性和凋亡相关蛋白FADD(Fas-associated death domain)表达水平.结果 问号钩体赖株感染1～6 h后,36.70%～63.70%的J774A.1细胞可H{现明显的早期凋亡,感染12 h时转变为晚期凋亡或坏死为主(53.68%).78.52%问号钩体赖株感染的A549细胞仪出现晚期凋亡或坏死.问号钩体赖株感染的EVC304细胞无细胞凋亡或坏死现象.感染的J774A.1细胞caspase-3和-8最大活性分别为(1453.41±36.07)和(1402.15±59.09)Fu,是未感染细胞的16.38和29.99倍.感染的J774A.1细胞caspase-9虽略有升高为(89.42±5.08)Fu,但明显低于caspase-3和-8(P<0.001).随着感染时间的延长,感染的J774A.1细胞FADD蛋白表达量逐步增加.结论 问号钩体诱导宿主细胞凋亡的效应町因细胞种类不同而有明显差异,FADD→caspase-8→caspase-3是介导问号钩体感染J774A.1细胞凋亡的主要信号通路.     

曲古抑菌素A通过JNK/MAPK信号通路介导乳腺癌MDA-MB-231细胞的凋亡

目的　探讨TSA对乳腺癌MDA-MB-231细胞增殖、凋亡的影响及作用机制。 方法　采用MTT、克隆形成、流式细胞术检测TSA对乳腺癌MDA-MB-231细胞生物学功能的影响;Western Blot 和qRT-PCR 检测细胞增殖、凋亡和MAPK信号通路蛋白及mRNA 的表达水平的影响;抑制JNK通路检测可能的作用机制。 结果　TSA呈剂量依赖性抑制细胞增殖和诱导凋亡,使细胞阻滞于G1期;TSA可上调P21、Caspase-3、Bax、p-JNK蛋白及mRNA表达,下调Cyclin D1、Cdk4、Bcl-2蛋白及mRNA表达;抑制JNK通路后,p-JNK蛋白和细胞总凋亡率降低,Caspase-3、Bax蛋白及mRNA表达减少,Bcl-2蛋白及mRNA表达增多。 结论　TSA通过MAPK信号通路介导JNK的磷酸化,调控乳腺癌MDA-MB-231细胞的凋亡。     

山柰酚通过Wnt/β-catenin信号通路抑制HBx-HepG2细胞增殖、侵袭及迁移

目的:探讨山柰酚对HBx-HepG2细胞增殖、侵袭及迁移的影响,并研究其潜在分子作用机制。方法:利用实时荧光定量PCR检测相关基因的表达水平,利用蛋白印迹实验检测相关蛋白的水平,流式细胞术检测细胞的凋亡率,MTT实验和平板集落形成实验检测细胞的增殖,Transwell侵袭实验和划痕愈合实验检测细胞的侵袭和转移。结果:山柰酚(10~200μmol/L)能够剂量和时间依赖性地抑制HBx-HepG2细胞的增殖。山柰酚(100μmol/L)能显著抑制HBx-HepG2细胞的集落形成数量、细胞侵袭能力以及细胞愈合率,诱导HBx-HepG2细胞凋亡,引起cleaved caspase-3、cleaved caspase-9及Bax蛋白水平上升,Bcl-2蛋白水平下降,降低β-catenin、c-Myc和cyclin D1 mRNA及蛋白的表达水平。山柰酚(100μmol/L)同时能够降低p-GSK-3β蛋白水平以及细胞质和细胞核中的β-catenin蛋白水平,对GSK-3β蛋白水平没有影响。Li Cl处理能够反转山柰酚(100μmol/L)对HBx-HepG2细胞的增殖、侵袭以及迁移抑制作用。结论:山柰酚对HBx-HepG2细胞的增殖、侵袭及转移有显著的抑制作用,这种抑制作用很有可能是通过抑制Wnt/β-catenin信号通路的活性来实现的。     

Wnt/β-catenin通路与NF-κB通路互相调控在创面愈合中的作用

正Wnt/β-catenin信号通路和核因子κB(nuclear factor kappa B,NF-κB)信号通路都是相对保守的信号通路,贯穿哺乳类动物的一生并可以调节很多生物学进程。研究显示,Wnt/β-catenin通路与NF-κB通路之间存在交互作用,且共同参与多方面的调控。创面愈合是一个复杂而有序的过程,是涉及炎性细胞、细胞外基质和细胞因子等多种因素的级联反应。     

血管内皮生长因子_(165)和白细胞介素-8促兔动脉粥样硬化斑块形成作用的探讨

目的 :观察血管内皮生长因子1 6 5(VEGF1 6 5)和白介素 8(IL 8)对兔动脉粥样硬化斑块形成的影响。方法 :15只日本大耳白兔随机分为 3组 :A组为对照组 ,普通饲料喂养 ,B、C组为处理组 ,高胆固醇饲料喂养。至第 3周 ( 2 1天 ) ,A组和B组肌注白蛋白 ( 2ug/kg) ,C组肌注VEGF1 6 5( 2ug/kg) ,之后继续饲养 3周 (共 4 2天 )处死动物 ,测定各组血清IL 8和血脂 ,用计量组织学的方法测定动脉斑块内CD34的阳性细胞数。结果 :① 2 1天及 4 2天时B组和C组分别与A组相比 ,血清IL 8浓度均有显著性升高 (P <0 .0 5)。C组 4 2天与 2 1天相比 ,血清IL 8水平明显增高 (P <0 .0 1)。② 4 2天时 ,各组之间CD34阳性细胞数比较有显著差异 (P <0 .0 5)。③ 4 2天时B组和C组IL 8的水平与CD34的阳性细胞数之间呈正相关 (B组r=0 .6 4,C组r=0 .88)。④各处理组内血脂水平比较 ,2 1天与 0天相比有明显升高 (P <0 .0 1) ,4 2天与 2 1天相比无显著差异。结论 :VEGF1 6 5促进斑块内血管生成的作用可能与其促进炎性细胞分泌有关。     

Wnt信号通路抑制剂对人神经胶质瘤细胞增殖活力和生长迁移的影响

目的:探讨Wnt信号通路在胶质瘤细胞增殖和生长迁移中的可能作用。方法:建立U251胶质瘤细胞培养体系、并给予不同浓度Wnt信号通路的抑制剂(IWR-1 0,2.5,5.0,10μmol/L)处理后,MTT测定增殖活力、划痕实验测定生长迁移、Western Blot测定Wnt5a、β-catenin蛋白表达水平,分析IWR-1的生物作用与效应途径。结果:MTT表明胶质瘤细胞的IWR-1 5.0、10μmol/L处理24 h、48 h组,细胞增殖活力显著低于对照组(P0.05~0.01)。划痕检测表明IWR-1 5.0、10μmol/L处理48 h组胶质瘤细胞的生长迁移能力低于对照组(P0.05~0.01)。Western Blot表明IWR-1处理48 h组胶质瘤细胞的β-catenin蛋白表达水平低于对照组(P0.05~0.01)。结论:Wnt信号抑制剂IWR-1能够明显抑制人胶质瘤细胞增殖和生长迁移,提示Wnt/β-catenin信号途径可能具有胶质瘤干预治疗靶点的潜在价值。