酪氨酸蛋白激酶抑制剂对自发性高血压大鼠血管平滑肌细胞增殖肥大的影响

为明确自发性高血压大鼠血管平滑肌细胞（SHR－VSMC）增殖与血小板源生长因子－AA（PDGF－AA），PDGF-α受体表达的关系及酪氨酸蛋白激酶在其中的作用，我们在培养的血管平滑肌细胞中，采用免疫印迹（western blot)3H-TdR及3H－Leu掺入等方法，观察在不同来源大鼠（SHR／Wistar)血管平滑肌细胞中，PDGF－AA，PDGF－α受体及PDGF－β受体表达的差异性；在PDGF－AA刺激下细胞的增殖，肥大反应及酪氨酸蛋白激酶抑制剂(genistein)对其的影响，结果表明，在SHR－VSM中PDGF－AA，PDGF－α受体蛋白表达明显高于Wistar-VSMC，而DGF－β受体蛋白表达在SHR－VSMC与Wistar-VSMC无明显差异，在不同浓度PDGF－AA（2、5、10、20)ng/ml刺激下，SHR－VSMC中PCNA表达呈剂量依赖性增高P＜0．01，加入酪氨酸激酶抑制剂，SHR－VSMC中PCNA表达呈剂量依赖性显著减少P＜0．01，在不同浓度PDGF－AA（2、5、10、20）ng/ml刺激下，SHR－VSMC中3H－Leu,3H-TdR掺入率呈剂量依赖性增强；加入酪氨酸激酶抑制剂SHR－VSMC中3H－Leu,3H-TdR掺入率显著减少，PDGF与其受体结合后，可激活受体细胞膜内的酪氨酸蛋白激酶，导致蛋白分子磷酸化的级联反应，启动MAPK，PKC等信号转导通路，调节特定基因的表达或通过改变细胞内相应蛋白质的功能状态导致细胞的增殖肥大，本实验应用酪氨酸激酶抑制剂genistein阻断酪氨酸激酶活性，证实阻断PDGF－AA所介导的自发性高血压大鼠血管平滑肌细胞增殖肥大，关键是阻断酪氨酸蛋白激酶的活性，酪氨酸蛋白激酶介导的信号转导在其中发挥重要作用。β     

p38MAPK表达与血管平滑肌细胞增殖关系的研究

目的探讨丝裂素活化蛋白激酶p38(p38MAPK)的表达与血管平滑肌细胞(VSMC)增殖的关系以及检测p38MAPK反义寡核苷酸(AODN)对VSMC增殖的抑制作用。方法将培养大鼠胸主动脉VSMC,随机分为对照组、p38MAPKAODN组、正义寡核苷酸(SODN)组。采用噻唑蓝比色分析法(MTT)和流式细胞仪检测VSMC,用蛋白免疫印迹法测定p38MAPK蛋白量。结果p38MAPKAODN能减少p38MAPK蛋白表达,明显抑制VSMC增殖,其抑制作用与p38MAPK蛋白表达相关,呈剂量依赖性。结论p38MAPKAODN能抑制大鼠VSMC增殖,该信号分子与VSMC增殖密切相关,可能是VSMC增殖的信号途径。     

p38丝裂素活化蛋白激酶介导自发性高血压大鼠血管平滑肌细胞增殖

目的 研究p38丝裂素活化蛋白激酶(p38MAPK)信号传导通路在血管紧张素Ⅱ(Ang Ⅱ)与血小板源性生长因子-BB(PDGF-BB)诱导的自发性高血压大鼠(SHR)血管平滑肌细胞(VSMC)增殖中的作用.方法 本实验采用体外培养SHR胸主动脉平滑肌细胞,用3H-胸腺嘧啶核苷([3H]-TdR)掺入法测定细胞增殖状况.用特异性的Phospho-p38MAPK抗体的蛋白免疫印迹法(Western blot)检测p38MAPK的活性.结果 1)Ang Ⅱ、PDGF成剂量依赖性促进SHR血管平滑肌细胞[3H]-TdR掺入率,当Ang Ⅱ为10-7 mol/L、PDGF为10 ng/L时,[3H]-TdR掺入率显著增加[Ang Ⅱ组:(11 588±1322)比对照组(2546±207)计数/min;PDGF:(5279±391)比对照组(2587±230)计数/min,P＜0.05].p38MAPK选择性阻断剂SB202190(10-9～10-7 mol/L)呈浓度依赖性地降低Ang Ⅱ、PDGF诱导的VSMC增殖活度.2)Ang Ⅱ、PDGF对p38MAPK的磷酸化均有显著增强作用,此作用同样被SB202190抑制.3者作用都呈剂量依赖性.结论 Ang Ⅱ、PDGF能激活SHR血管平滑肌细胞的p38MAPK发生磷酸化,进而导致血管平滑肌细胞增殖.     

曲古菌素A对血管平滑肌细胞p27kip1表达的调控机制研究

目的探讨组蛋白去乙酰化酶抑制剂曲古菌素A（Trichostatin A，TSA）对血管平滑肌细胞（VSMC）的p27kip1表达的影响和调控机制。方法半定量逆转录聚合酶链反应（RT—PCR）检测p27kip1的mRNA水平，蛋白印迹测定p27kip1和S-phase kinase—associated protein-2（skp2）蛋白表达，荧光分光光度法测定20S蛋白酶体活性。结果100ng／ml TSA不影响VSMC中p27kip1的mRNA水平。100ng／ml TSA显著抑制血清诱导的p27kip1蛋白下调，并延长p27kip1蛋白的半衰期。100ng／mlTSA抑制血清诱导的skp2表达上调，且skp2表达与相应时点p27kip1蛋白呈负相关。100ng／ml TSA对20S蛋白酶体活性物影响。结论TSA对VSMC的p27kip1表达调控不是在转录水平上，而是通过翻译后机制抑制血清诱导VSMC的p27kip1蛋白降解，其机制可能与TSA抑制泛素连接酶亚单侍skp2表达有关．     

miR-145抑制VSMC增殖的作用及其相关信号通路研究

目的探讨miR-145对PDGF-BB诱导的大鼠原代血管平滑肌细胞(VSMC)的作用及丝裂原激活的蛋白激酶(MAPK)信号转导途径的作用。方法体外培养大鼠原代VSMC,再将细胞分为空白对照组、miR-NC组、PDGF-BB+miR-145组及PDGF-BB组。CCK-8法检测各组细胞的增殖情况;实时RT-PCR方法检测PCNA、c-Jun及SM22a的表达水平;Western印迹方法检测ERK1/2和p-ERK1/2的表达、JNK和p-JNK的表达以及p38MAPK和p-p38MAPK的表达。结果 miR-145过表达后能够抑制PDGF诱导的大鼠原代VSMC增殖,并下调VSMC增殖相关基因PCNA、c-Jun的表达、上调分化相关基因SM22a的表达;PDGF-BB诱导VSMC后,ERK、JNK、p38MAPK的磷酸化水平均明显上调,而转染miR-145慢病毒后再加PDGF刺激,ERK、JNK、p38MAPK的磷酸化水平均明显下调。结论 miR-145能够抑制去分化型VSMC中的MAPK信号通路,进而抑制VSMC的增殖。     

丝裂素活化蛋白激酶的激活和转核与大鼠 血管平滑肌细胞增殖关系的研究

目的 探讨丝裂素活化蛋白激酶（MAPK）激活、转核与血管紧张素Ⅱ（AngⅡ)刺激血管平滑肌细胞（VSMC）增殖间的关系。方法 本实验采用培养大鼠胸主动脉VSMC。用^3H-胸腺嘧啶核苷（^3H-TdR)掺入法测定DNA合成,用p43/p44磷酸化抗MAPK抗体的蛋白免疫印迹法测定MAPK蛋白量,用免疫细胞化学技术观察MAPK活化并转位入细胞核的过程。结果 （1）AngⅡt和PD98059的上述作用都呈剂量依赖性。（2）AngⅡ对MAPK蛋白表达有显著增强作用。此作用同样被PD98059以剂量依赖方式抑制。（3）AngⅡ刺激5min后,MAPK出现在VSMC的细胞浆中,30min时MAPK进入细胞核,3h后MAPK染色从核内消失,上述MAPK转核过程被PD98059抑制。结论 本实验证实人细胞核,3h后MAPK染色从核人消失,上述MAPK转核过程被PD98059抑制。结论 本实验证实AngⅡ能激活培养大鼠主动脉VSMC的MAPK,活化的MAPK从细胞浆转位进入细胞核导致VSMC增殖。     

p38丝裂素活化蛋白激酶介导自发性高血压大鼠血管平滑肌细胞增殖

目的研究p38丝裂素活化蛋白激酶(p38MAPK)信号传导通路在血管紧张素Ⅱ(AngⅡ)与血小板源性生长因子-BB(PDGF-BB)诱导的自发性高血压大鼠(SHR)血管平滑肌细胞(VSMC)增殖中的作用。方法本实验采用体外培养SHR胸主动脉平滑肌细胞,用3H-胸腺嘧啶核苷([3H]-TdR)掺入法测定细胞增殖状况。用特异性的Phospho-p38MAPK抗体的蛋白免疫印迹法(Westernblot)检测p38MAPK的活性。结果1)AngⅡ、PDGF成剂量依赖性促进SHR血管平滑肌细胞[3H]-TdR掺入率,当AngⅡ为10-7mol/L、PDGF为10ng/L时,[3H]-TdR掺入率显著增加[AngⅡ组:(11588±1322)比对照组(2546±207)计数/min;PDGF:(5279±391)比对照组(2587±230)计数/min,P<0.05]。p38MAPK选择性阻断剂SB202190(10-9～10-7mol/L)呈浓度依赖性地降低AngⅡ、PDGF诱导的VSMC增殖活度。2)AngⅡ、PDGF对p38MAPK的磷酸化均有显著增强作用,此作用同样被SB202190抑制。3者作用都呈剂量依赖性。结论AngⅡ、PDGF能激活SHR血管平滑肌细胞的p38MAPK发生磷酸化,进而导致血管平滑肌细胞增殖。     

缬沙坦对血管平滑肌细胞迁移及丝裂原活化蛋白激酶的影响

目的观察缬沙坦（Val）对血管紧张素Ⅱ（AngⅡ）刺激下大鼠血管平滑肌细胞（VsMC）迁移及磷酸化42／44丝裂原活化蛋白激酶（p42／44MAPK）表达的影响。方法组织贴块法培养大鼠胸主动脉平滑肌细胞,tran-sweⅡ小室检测细胞的迁移能力,免疫印迹法检测p42／44MAPK蛋白表达的水平。结果（1）AngⅡ能明显促进VSMC迁移,该作用可被Val和MAPK激酶的特异性抑制剂PD98059所抑制。（2）AngⅡ刺激VSMC5min时,p42／44MAPK的表达量最大,该作用可被Val和PD98059所抑制。（3）Val单独作用于VSMC时,对细胞的迁移及p42／44MAPK的表达均无明显影响。结论Val抑制AngⅡ诱导的VSMC迁移与其抑制AngⅡ诱导的p42／44MAPK的表达相关。     

泽泻汤对氧化型低密度脂蛋白诱导血管平滑肌细胞增殖的影响

目的观察泽泻汤对血管平滑肌细胞(VSMC)周期蛋白Cyclin D1、Cyclin E、增殖细胞核抗原(PCNA)和p27表达的影响,探讨泽泻汤在氧化型低密度脂蛋白(ox-LDL)诱导的VSMC增殖中的作用和机制。方法通过体外50 mg/L ox-LDL诱导VSMC,建立VSMC增殖的动脉粥样硬化细胞模型;应用空白血清及20%泽泻汤含药血清干预。MTS法检测泽泻汤含药血清对VSMC增殖的影响;Western blot检测增殖相关蛋白Cyclin D1、Cyclin E、PCNA和p27表达水平。结果 50 mg/L ox-LDL可明显诱导VSMC增殖。与ox-LDL组比较,泽泻汤含药血清可显著抑制ox-LDL诱导的VSMC增殖,下调细胞Cyclin D1、Cyclin E和PCNA的表达,同时促进p27蛋白表达。结论泽泻汤具有抗VSMC增殖的作用,机制可能与上调p27蛋白和抑制Cyclin D1、Cyclin E、PCNA表达有关。     

血小板源生长因子和血管紧张素Ⅱ对血管平滑肌细胞中p57基因表达的影响

为观察血小板源生长因子BB和血管紧张素Ⅱ对血管平滑肌细胞p57蛋白和基因表达的影响及其在血管平滑肌细胞增殖增生中的作用。用贴壁法培养鼠胸主动脉平滑肌细胞,加入血小板源生长因子BB 20ug/L或血管紧张素Ⅱ 1umol/L刺激24h,用Western蛋白印迹法检测p57蛋白水平,用DNA芯片技术检测p57 mRNA的表达量,结果发现,血小板源生长因子BB刺激组p57 mRNA和p57蛋白表达量明显高于血管紧张素Ⅱ刺激组,分别为后者的2．47倍和1．7倍,而血管紧张素Ⅱ刺激组p57蛋白表达量与对照组接近,保持在较低水平,研究结果提示,在血小板源生长因子刺激引起的血管平滑肌细胞增殖过程中p57基因表达明显增高,p57基因的高表达可能起抑制血管平滑细胞过度增殖的作用。     

Potentiation of mitogenic activity of platelet-derived growth factor by physiological concentrations of insulin via the MAP kinase cascade in rat A10 vascular smooth muscle cells

Hyperinsulinemia has been shown to be associated with diabetic angiopathy. Migration and proliferation of vascular smooth muscle cells (VSMC) are the processes required for the development of atherosclerosis. In this study, we attempted to determine whether insulin affects mitogenic signaling induced by platelet-derived growth factor (PDGF) in a rat VSMC cell line (A10 cells). PDGF stimulated DNA synthesis which was totally dependent on Ras, because transfection of dominant negative Ras resulted in complete loss of PDGF-stimulated DNA synthesis. Initiation of DNA synthesis was preceded by activation of Raf-1, MEK and MAP kinases (Erk 1 and Erk2). Treatment of the cells with PD98059, an inhibitor of MAPK kinase (MEK) attenuated but did not abolish PDGF-stimulated DNA synthesis, suggesting that MAPK is required but not essential for DNA synthesis. PDGF also stimulated phosphorylation of protein kinase B (Akt/PKB) and p70 S6Kinase (p70S6K) in a wortmannin-sensitive manner. Rapamycin, an inhibitor of p70S6K, markedly suppressed DNA synthesis. Low concentrations of insulin (1-10 nmol/l) alone showed little mitogenic activity and no significant effect on MAPK activity. However, the presence of insulin enhanced both DNA synthesis and MAPK activation by PDGF. The enhancing effect of insulin was not seen in cells treated with PD98059. Insulin was without effect on PDGF-stimulated activations of protein kinase B (Akt/PKB) and p70S6K. We conclude that insulin, at pathophysiologically relevant concentrations, potentiates the PDGF-stimulated DNA synthesis, at least in part, by potentiating activation of the MAPK cascade. These results are consistent with the notion that hyperinsulinemia is a risk factor for the development of atherosclerosis.     

大黄素通过p53途径抑制血管平滑肌细胞增殖的实验研究

目的探讨p53途径在大黄素抑制血管平滑肌细胞增殖作用中的地位。方法通过细胞计数、老化相关β-半乳糖苷酶染色、Annexin V标记等方法观察大黄素抑制血管平滑肌细胞增殖的特点。^3H-胸苷掺入法测定DNA合成、流式细胞仪了解细胞周期变化、Western blot检测p53蛋白表达变化、基因芯片观察mRNA表达水平。结果（1）1．6～3．1μg／ml大黄素延缓细胞生长,6．3～12．5μg／ml大黄素促进细胞老化,25．0μg／ml大黄素则可显著诱导细胞凋亡。（2）大黄素干预24h后,出现非计划性DNA合成现象,这是DNA损伤的敏感性标志。p53基因和蛋白表达水平呈大黄素浓度依赖性上调。除了细胞增殖基因表达下调,其他基因表达均上调,如细胞老化基因、细胞凋亡基因、DNA损伤修复基因。（3）大黄素能够迅速渗透进入细胞,在细胞内的分布具有明显的选择性,绝大多数以颗粒形态分布于细胞胞浆中,细胞核中也有少量分布。结论大黄素通过损伤DNA激活p53途径。随着大黄素浓度升高,p53途径激活程度也随之增强并产生多种细胞增殖抑制效应,即生长停滞、细胞老化和细胞凋亡。     

Kallistatin stimulates vascular smooth muscle cell proliferation and migration in vitro and neointima formation in balloon-injured rat artery

Kallistatin, a serine proteinase inhibitor (serpin), is expressed in the endothelial and smooth muscle cells of blood vessels. The potential function of kallistatin in vascular biology was investigated by studying its role in the proliferation and migration of cultured primary aortic vascular smooth muscle cells (VSMCs) in vitro and in neointima formation in rat artery after balloon angioplasty in vivo. Exogenous kallistatin induced a >2-fold increase of VSMC proliferation and cell growth as measured by [(3)H]thymidine incorporation and cell counts and a 2.3-fold increase of cell migration in modified Boyden chambers. In balloon-injured vessels, endogenous kallistatin mRNA and protein levels increased up to 10-fold as determined by competitive polymerase chain reaction and by ELISA. Intense staining of kallistatin mRNA was identified in the proliferating VSMCs of balloon-injured arteries during cell migration from media to neointima by in situ hybridization histochemistry and immunohistochemistry. We observed an induction of kallistatin expression by platelet-derived growth factor (PDGF) and upregulation of p42/44 mitogen-activated protein kinase (MAPK) activity by kallistatin in cultured VSMCs. Conversely, adenovirus-mediated transfer of kallistatin antisense cDNA into cultured VSMCs inhibited PDGF-induced p42/44 MAPK activity and cell proliferation. Furthermore, local delivery of adenovirus carrying kallistatin antisense cDNA significantly downregulated kallistatin mRNA levels and attenuated neointima formation in balloon-injured rat arteries in vivo. These results indicate that kallistatin may play an important role in mediating PDGF-induced MAPK pathway on VSMC proliferation and in neointima formation after balloon angioplasty.     

Role of epidermal growth factor in pathogenesis of uterine leiomyomas

Objective:To investigate the role of epidermal growth factor(EGF) in the pathogenesis of uterine leiomyomas.Methods:Human myometrial smooth muscle cells(HM-SMCs) and smooth muscle cells of human uterine leiomyomas(HL-SMCs) were separated from patients' specimens and cultured.After processed by EGF or PD98059(inhibitor of MKK/MEK) +EGF,the proliferation rate of both SMCs was detected by BrdU method and the phosphorylation level of p44/42 mitogen-activated protein kinase(MAPK) was determined by Western-blot.After different processing time by EGF,the phosphorylation levels of p44/42 MAPK and AKT and p27 expression level in both SMCs were detected by Western-blot.Results:EGF could significantly promote HL-SMCs proliferation and PD98059 could inhibit this effect(P0.05);besides,PD98059 could inhibit the increase of the phosphorylation level of p44/42 MAPK in both SMCs induced by EGF.When the processing time by EGF was over 15 min,the phosphorylation levels of p44/42 MAPK and AKT in both SMCs decreased sharply and were close to zero:p27 expression in HM-SMCs raised significantly while the upregulation in HL-SMCs was little.Conclusions:EGF could not cause activation of EGFR because of the dephosphorylation of p44/42 MAPK and AKT in HL-SMCs,which caused p27 expression insufficiently and cell cycle dysregulation.     

The inhibitory mechanisms of amlodipine in human vascular smooth muscle cell proliferation.

The abnormal proliferation of vascular smooth muscle cells (VSMCs) is closely related to vascular diseases. There is growing evidence that calcium antagonists inhibit VSMC growth/proliferation, yet their molecular mechanisms remain to be determined. Recent reports suggest that p42/p44 mitogen-activated protein kinases (MAPKs) play an important role in cell growth and proliferation induced by growth factors. This study was designed to determine whether these MAPKs are involved in VSMC proliferation induced by basic fibroblast growth factor (bFGF) and to examine the inhibitory effect of amlodipine. Human VSMCs were obtained from inner mammary artery. p42/p44 MAPKs activity was measured by immunoblotting assay using anti-p42/p44 phospho-MAPK antibody. 1) bFGF (20 ng/ml) significantly activated p42/p44 MAPKs with a peak time of 5-15 min, which was maintained for 3 h. PD98059 (100 nM-10 microM), a specific inhibitor of MAPK kinase, inhibited bFGF-induced p42/p44 MAPKs activation in a dose-dependent manner. 2) Amlodipine (1-100 nM) dose-dependently inhibited p42/p44 MAPKs activation by bFGF. 3) Amlodipine (10 nM) could inhibit both short-term and long-term p42/p44 MAPKs activation by bFGF. Our results indicate that bFGF could activate p42/p44 MAPKs. Amlodipine, which could inhibit bFGF-induced human VSMC proliferation, inhibited both short-term and sustained p42/p44 MAPKs activation by bFGF, suggesting that bFGF-induced VSMC proliferation may be related to p42/p44 MAPKs activation, and that the antiproliferative effect of amlodipine may be related to its inhibition of p42/p44 MAPKs activation.     

三七总皂甙对血管平滑肌细胞增殖及c-myc基因表达的影响

目的探讨三七总皂甙对血小板源生长因子刺激的血管平滑肌细胞增殖的影响及其可能机制。方法运用血小板源生长因子刺激兔体外血管平滑肌细胞增殖模型,通过四甲基偶氮唑盐比色法、流式细胞术及免疫细胞化学法观察三七总皂甙对其增殖活性、细胞周期及c-myc蛋白表达的影响。结果血小板源生长因子显著刺激血管平滑肌细胞增殖,三七总皂甙呈浓度依赖性抑制血管平滑肌细胞增殖,对血小板源生长因子诱导的血管平滑肌细胞增殖亦具有显著抑制作用;三七总皂甙作用下血管平滑肌细胞处于G1/G0期的细胞数增多,而G2/S期的细胞数显著减少,c-myc蛋白的表达亦降低。结论三七总皂甙对基础状态下及血小板源生长因子诱导的血管平滑肌细胞增殖均具有显著抑制作用,部分机制与其阻滞血管平滑肌细胞G1/G0期向S期转化以及下调c-myc基因表达有关。