iNOS及ERK1/2信号转导通路在17β-雌二醇抑制血管平滑肌细胞增殖中的作用

目的: 观察诱导型一氧化氮合酶（inducible nitric oxide synthase,iNOS）及细胞外信号调节激酶1/2（ERK1/2）信号转导通路在17β-雌二醇（17β-estradiol,E2）抑制血管平滑肌细胞（vascular smooth muscle cells,VSMCs）增殖中的作用。方法: 采用MTT比色法和Western blot技术,检测E2预处理前后胎牛血清（fetal calf serum,FCS）对VSMCs中DNA合成、iNOS表达及磷酸化的ERK1/2蛋白表达的影响。结果: E2作用24 h,可明显抑制FCS诱导的VSMCs增殖。Western blot的结果显示,FCS孵育VSMCs后,iNOS蛋白的表达下降,磷酸化的ERK1/2蛋白表达增加。E2预处理后,可增加iNOS蛋白的表达,抑制磷酸化ERK1/2蛋白表达。若提前应用iNOS阻断剂L-精氨酸甲酯（L-NAME）孵育VSMCs,可部分逆转E2诱导的磷酸化的ERK1/2蛋白表达下降的效应。结论: E2可抑制FCS诱导的VSMCs增殖,其作用可能与增加iNOS蛋白的表达,抑制磷酸化的ERK1/2表达有关。     

醛固酮对肝星状细胞早期生长反应因子-1信号通路调控的体外研究

目的探讨醛固酮（Aldo）对肝星状细胞（HSC）早期生长反应因子-1（EGR1）信号传导通路的影响。方法采用HSC-T6细胞株，分别给予Aldo 1μmol／L处理10min、30min、1h、2h和3h，western blot检测磷酸化p42／44蛋白的表达。另外，观察细胞外信号调节激酶（ERK）1／2特异性阻断剂U0126、抗氧化剂N-乙酰半胱氨酸（NAC）（均预先处理60min，再给予Aldo刺激）和肿瘤坏死因子α对磷酸化p42／44蛋白表达的影响。此外，给予Aldo、U0126和NAC处理后，用电泳迁移率分析（EMSA）检测EGR-1 DNA结合活性的变化；western blot检测血小板衍生生长因子-B（PDGF-B）蛋白的表达。免疫细胞化学检测Aldo对HSC PDGF-B蛋白表达的影响。结果Aldo可诱导磷酸化p42／44的表达，U0126可抑制磷酸化p42／44的表达。EMSA结果显示：Aldo干预HSC 30min后EGR-1 DNA结合活性开始增加，1h达到峰值，然后逐渐减低；U0126可显著抑制Aldo诱导的EGR-1活性增强；NAC对Aldo诱导的EGR-1活性无抑制作用。Aldo可诱导HSC PDGF-B蛋白表达；U0126和NAC对PDGF—B表达无抑制作用。结论Aldo可经ERK1／2通路诱导HSC EGR-1活性增强。Aldo可经EGR—1通路调控PDGF—B的表达。     

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。     

反义MAPK寡核苷酸可抑制血管升压素诱导的心肌成纤维细胞一氧化氮合酶活性

目的探讨反义丝裂素活化蛋白激酶（MAPK）寡核苷酸对血管升压素（VP）诱导的心肌成纤维细胞（CFs）一氧化氮合酶（NOS）活性的抑制作用。方法分离培养SD仔鼠CFs,采用分光光度法和RT-PCR测定CFs NOS活性和诱导型一氧化氮合酶（iNOS）mRNA表达。结果VP显著提高CFs NOS活性和iNOS mRNA表达;反义MAPK寡核苷酸剂量依赖性地抑制VP诱导下CFs NOS活性增高和iNOS mRNA表达增强,其中0.2μmol/L和0.3μmol/L反义MAPK寡核苷酸可将VP诱导下CFs NOS活性和iNOS mRNA表达抑制到与对照组近似水平。结论MAPK参与了VP诱导下CFs NOS活性增高和iNOS mRNA表达增强。     

脂氧素A4抑制结缔组织生长因子诱导的系膜细胞产生Fractalkine

目的：检测结缔组织生长因子（connective tissue growth factor，CTGF）是否诱导肾小球系膜细胞产生Fractalkine；检测脂氧素A4（lipoxin A4，LXA4）是否调节CTGF对合成Fraetalkine的作用，并探讨其作用机制。方法：应用CTGF刺激培养的大鼠肾小球系膜细胞，应用逆转录多聚酶链反应测定Fractalkine mRNA表达，应用酶联免疫吸附试验测定上清液中Fractalkine蛋白表达。应用趋化试验测定上清液对单核细胞（THP-1）的趋化作用。应用Western blot测定分裂原激活的蛋白激酶（p42／44 mitogen-activated protein kinase，p42／44 MAPK）、磷脂酰肌醇3-激酶（phosphoinflsilide 3-kinase，PI3-K）、蛋白激酶B（protein kinase B，PKB）。应用凝胶电泳迁移率试验测定核因子-κB（nuclear factor-κB，NF-κB）。结果：CTGF刺激使系膜细胞Fractalkine mRNA表达与分泌量增加，增加磷酸化p42／44 MAPK、P-PI3-K、P-PKB及NF-κB表达。P-p42／44 MAPK抑制剂PD98059抑制CTGF诱导的p42／p44 MAPK磷酸化与Fractalkine分泌。PI3-K抑制剂LY294002抑制CTGF诱导的PI3-K、PKB、NF-κB活化与Fractalkine分泌。NF-κB抑制剂吡咯烷二硫氯基甲酸酯（pyrrolidine dithio-carbamate，PDTC）抑制CTGF诱导的NF-κB活化与Fractalkine分泌。LXA4呈剂量依赖性地抑制CTGF所致的上述变化。结论：LXA4可抑制CTGF引起的系膜细胞分泌Fractalkine，其机制依赖于抑制p42／p44 MAPK、PI3-K／PKB的磷酸化与NF-κB活化。     

醛固酮对肝星状细胞激活蛋白- 1通路调控的体外研究

目的 探讨醛固酮（Aldo）对肝星状细胞（HSC）激活蛋白-1（AP—1）信号转导通路的影响。方法 采用HSCT6细胞株，分别予Aldo 1μmol／L处理10、30、60、120、180min，蛋白质印迹法检测磷酸化P42／44蛋白的表达。另外，观察细胞外信号调节激酶（ERK）特异性抑制剂-U0126，抗氧化剂-乙酰半胱氨酸（NAC）（均先预处理60min，再予Aldo刺激）和肿瘤坏死因子α（TNFα）对磷酸化P42／44蛋白表达的影响。Aldo在干预30、60、120、240min后，电泳迁移率变更分析（EMSA）检测AP-1 DNA结合活性的变化；予U0126和NAC干预后，EMSA检测AP-1 DNA结合活性；逆转录聚合酶链反应检测α1-1型前胶原基因的表达。结果 Aldo可诱导磷酸化P42／44的表达，并呈时间依赖性，10min达到峰值，之后逐渐减低。U0126可抑制磷酸化P42／44的表达。Aldo可增强HSC的AP-1的DNA结合活性。U0126可以显著抑制Aldo诱导的AP—1的活化，NAC部分抑制Aldo诱导的AP-1的活化。Aldo可诱导α1-1型前胶原mRNA的表达。U0126和NAC可显著抑制Aldo诱导的α1-1型前胶原mRNA表达增强。结论 Aldo可经ERK通路诱导HSC AP-1结合活性增强。Aldo可经AP-1通路调控α1-1型前胶原基因的表达。     

针对STAT3的siRNA抑制HepG2细胞增殖和p44/42MAPK蛋白的表达

目的研究STAT3信号传导通路对HepG2细胞p44/42MAPK蛋白表达和细胞生长的影响。方法将针对STAT3的siRNA转染入HepG2细胞以沉默STAT3基因的表达,采用MTT法检测细胞生长,采用Western blot法检测STAT3和p44/42MAPK蛋白的表达。结果对照组和lipofectamineTM2000处理组细胞生长无明显差异(q=0.97,P0.05),而siRNA处理组细胞生长被明显抑制(q=9.36,P0.05);SiRNA转染后24h、48h、72h和96h,细胞抑制率分别为33.2%、39.6%4、3.1%和33.9%s,iRNA在96h后抑制作用减弱,细胞开始重新繁殖;转染细胞72h和96h后,可见STAT3蛋白表达均被抑制(t=14.12,P0.05),p44/42MAPK蛋白表达未被抑制(F=3.99,P0.05),而p-p44/42MAPK蛋白表达增加(t=16.30,P0.05)。结论 STAT3信号传导通路可以影响细胞生长及p44/42MAPK蛋白质的磷酸化,而p-p44/42MAPK的表达增加可能代偿了沉默STAT3引起的细胞生长抑制,使细胞重新繁殖。     

诱导型一氧化氮合酶和解偶联蛋白-2对心肌缺血预适应的作用

目的 探讨诱导型一氧化氮合酶（inducible nitric oxide synthase,iNOS）和解偶联蛋白-2（uncoupling protein-2,UCP2）对大鼠心肌缺血预适应的保护机制。方法 结扎左冠状动脉复制大鼠心肌缺血再灌注模型。预适应组行3次缺血5min,再灌注10min的预处理,分别于预处理0,6,12,24和48h（分别为0,6,12,24和48h亚组）后行30min缺血及120min再灌注：对照组开胸后不结扎左冠状动脉,电镜观察心肌超微结构,据Rainio评分标准进行心肌超微结构损伤程度的半定量分析。采用Western Blot及比色法检测心肌UCP2活性及iNOS活性。结果 预适应各亚组UCP2活性均增高（P〈0．05）,0h亚组UCP2表达水平最高（P〈0．01）,24小时亚组和48小时亚组心肌iNOS活性显著升高（P〈0．05）。结论 UCP2和iNOS共同参与了大鼠心肌缺血预适应心肌保护作用。     

p38MAPK对肉豆蔻提取物干预的小胶质细胞CREB表达的影响

目的探讨肉豆蔻提取物对鼠性小胶质BV2细胞的调控作用。方法应用WST-8试剂盒和Westernblot技术,观察肉豆蔻提取物对体外培养的鼠性小胶质BV2细胞的生存率及脂多糖（LPS）诱导的p38MAPK、磷酸化p38MAPK和cAMP应答元件结合蛋白（CREB）表达的影响。结果肉豆蔻提取物对BV2细胞无毒性,且抑制LPS所诱导的磷酸化p38MAPK和CREB的表达。结论肉豆蔻提取物可抑制LPS所诱导的小胶质细胞p38MAPK磷酸化和CREB的表达。     

内分泌腺来源的血管内皮生长因子抑制胰腺癌细胞凋亡的信号转导机制研究

目的 探讨内分泌腺来源的血管内皮生长因子(EG-VEGF)在胰腺癌MiaPaCa细胞中抗凋亡作用及其相关分子机制.方法 以50、100、200 ng/ml EG-VEGF处理细胞,采用流式细胞仪检测细胞凋亡,蛋白质印迹法检测细胞p42/44MAPK、STAT3蛋白表达及其磷酸化,检测抗凋亡蛋白Mcl-1的表达.应用G蛋白耦联非特异受体阻断剂PTX、Rsa/ERK信号通路阻断剂PD98059和JAK/STAT3信号通路阻断剂AG490预处理细胞1 h,观察Mcl-1蛋白表达的变化.结果 100 ng/ml EG-VEGF可使MiaPaCa细胞的凋亡率从(28.4±4.6)%显著下降到(13.2±2.5)%(P<0.05).50 ng/ml的EG-VEGF处理后,MiaPaCaⅡ细胞p42/44MAPK的磷酸化增加(1.735 ±0.019)倍;STAT3的磷酸化增加(21.810±0.052)倍,均较对照组显著增加(P值均<0.05),但100、200 ng/ml EG-VEGF没有进一步增加蛋白的磷酸化.50 ng/ml的EG-VEGF处理后,Mcl-1蛋白的表达较对照组增加(3.460±0.002)倍,但100、200ng/ml EG-VEGF没有进一步增加蛋白的表达;应用PTX预处理后,Mcl-1蛋白表达的增加被完全抑制,用PD98059、AG490预处理后Mcl-1表达增加抑制率分别为52%和68%.结论 EG-VEGF可抑制MiaPaCa细胞的凋亡,其机制可能与激活Ras-MAPK和JAK-STAT3信号转导通路及增加Mcl-1蛋白的表达有关.     

Specific contribution of estrogen receptors on mitogen-activated protein kinase pathways and vascular cell activation

Randomized clinical trials have not provided conclusive data that hormone replacement therapy confers cardioprotection against coronary artery disease in postmenopausal women. However, other studies have shown that estrogens can induce beneficial effects on the vasculature. Nevertheless, the specific contribution of estrogen receptors (ERs) alpha and beta on vascular cells is not well characterized. Therefore, we used an antisense gene therapy approach to investigate the contribution of ERalpha and ERbeta on p38 and p42/44 mitogen-activated protein kinase (MAPK) activation and on vascular cell responsiveness. Treatment of porcine smooth muscle cells (PSMCs) with platelet-derived growth factor-BB induced p38 and p42/44 MAPK activation and their migration and proliferation. These effects were prevented by pretreatment with 17beta-estradiol (17betaE). The inhibitory effects of 17betaE on PSMCs were abrogated by the downregulation of ERbeta protein expression with selective ERbeta mRNA antisense oligomers, whereas the downregulation of ERalpha had no effect. However, treatment of porcine aortic endothelial cells with 17betaE promoted p38 and p42/44 MAPK phosphorylation and their migration and proliferation. These effects were ERalpha dependent, as defined by antisense gene therapy. These results suggest that in PSMCs, 17betaE reduces p42/44 and p38 MAPK activity through ERbeta stimulation, whereas in contrast, in porcine aortic endothelial cells, 17betaE induces p42/44 and p38 MAPK through ERalpha activation. 17betaE may contribute to the vascular healing process and to the prevention of restenosis by improving reendothelialization through ERalpha activation and by decreasing smooth muscle cell migration and proliferation through ERbeta stimulation.     

Chlamydia pneumoniae and chlamydial heat shock protein 60 stimulate proliferation of human vascular smooth muscle cells via toll-like receptor 4 and p44/p42 mitogen-activated protein kinase activation

An early component of atherogenesis is abnormal vascular smooth muscle cell (VSMC) proliferation. The presence of Chlamydia pneumoniae in many atherosclerotic lesions raises the possibility that this organism plays a causal role in atherogenesis. In this study, C pneumoniae elementary bodies (EBs) rapidly activated p44/p42 mitogen-activated protein kinases (MAPKs) and stimulated proliferation of VSMCs in vitro. Exposure of VSMCs derived from human saphenous vein to C pneumoniae EBs (3x10(7) inclusion forming units/mL) enhanced bromodeoxyuridine (BrdU) incorporation 12+/-3-fold. UV- and heat-inactivated C pneumoniae EBs also stimulated VSMC proliferation, indicating a role of direct stimulation by chlamydial antigens. However, the mitogenic activity of C pneumoniae was heat-labile, thus excluding a role of lipopolysaccharide. Chlamydial hsp60 (25 microg/mL) replicated the effect of C pneumoniae, stimulating BrdU incorporation 7+/-3-fold. Exposure to C pneumoniae or chlamydial hsp60 rapidly activated p44/p42 MAPK, within 5 to 10 minutes of exposure. In addition, PD98059 and U0126, which are two distinct inhibitors of upstream MAPK kinase 1/2 (MEK1/2), abolished the mitogenic effect of C pneumoniae and chlamydial hsp60. Toll-like receptors (TLRs) act as sensors for microbial antigens and can signal via the p44/p42 MAPK pathway. Human VSMCs were shown to express TLR4 mRNA and protein, and a TLR4 antagonist abolished chlamydial hsp60-induced VSMC proliferation and attenuated C pneumoniae-induced MAPK activation and VSMC proliferation. Together these results indicate that C pneumoniae and chlamydial hsp60 are potent inducers of human VSMC proliferation and that these effects are mediated, at least in part, by rapid TLR4-mediated activation of p44/p42 MAPK.     

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.     

Role of p42/p44 mitogen-activated-protein kinase and p21waf1/cip1 in the regulation of vascular smooth muscle cell proliferation by nitric oxide

The purpose of this study was to determine the involvement of the p42/p44 mitogen-activated protein kinase (MAPK) pathway and induction of p21(waf1/cip1) in the antiproliferative effects of nitric oxide (NO) on rat aortic smooth muscle cells (RASMC). NO, like alpha-difluoromethylornithine (DFMO), interferes with cell proliferation by inhibiting ornithine decarboxylase (ODC) and, therefore, polyamine synthesis. S-nitroso-N-acetylpenicillamine or (Z)-1-[N-(2-aminoethyl)-N-(2-aminoethyl)-amino]-diazen-1-ium-1,2-diolate inhibited RASMC growth at concentrations as low as 3 microM, and DFMO elicited effects at concentrations of 100 microM or greater. The cytostatic effect of NO and DFMO was prevented by the MAPK kinase 1/2 inhibitors PD 098,059 or U0126. This finding suggests that the p42/p44 MAPK pathway is involved in the inhibition of RASMC proliferation by NO. Western blot analysis revealed that treatment of RASMC with NO or DFMO leads to activation of p42/p44 MAPK and induction of p21(waf1/cip1). This effect was prevented by MAPK kinase 1/2 inhibitors, suggesting that induction of p21(waf1/cip1) depended on activation of p42/p44. Moreover, activation of p42/p44 and induction of p21(waf1/cip1) were prevented by exogenous putrescine but not ornithine, suggesting this effect was due to the inhibition of ODC by NO or DFMO. Finally, activation of p42/p44 MAPK and induction of p21(waf1/cip1) were cGMP-independent. Neither 1H-(1,2,4)oxadiazolo[4,3-alpha]quinoxalin-1-one nor zaprinast influenced the cytostatic effect of NO or DFMO or their ability to activate these signal transduction pathways. These observations suggest that inhibition of ODC and accompanying putrescine production are the underlying mechanisms by which NO and DFMO activate the MAPK pathway to promote induction of p21(waf1/cip1) and consequent inhibition of cell proliferation.     

N-Acetyl-L-cysteine potentiates interleukin-1beta induction of nitric oxide synthase : role of p44/42 mitogen-activated protein kinases

We have reported previously that N-acetyl-L-cysteine facilitated interleukin-1beta-induced nitric oxide synthase (iNOS) expression in rat vascular smooth muscle cells. The present study compares the effect of N-acetyl-L-cysteine with other antioxidants and tested the possibility that N-acetyl-L-cysteine potentiates iNOS induction by a mechanism involving activation of p44/42 mitogen-activated protein kinases (MAPKs). The effect of N-acetyl-L-cysteine on potentiating interleukin-1beta-induced nitrite production and iNOS expression was mimicked either by the enantiomers, L-cysteine and D-cysteine, or by a non-thiol-containing antioxidant, L-ascorbic acid. Interleukin-1beta activated p44/42 MAPK, and this activation was enhanced in the presence of N-acetyl-L-cysteine. Inhibition of p44/42 MAPK phosphorylation by the selective inhibitor PD98059 clearly inhibited iNOS expression induced by interleukin-1beta either in the absence or in the presence of N-acetyl-L-cysteine. These observations, combined with previous results, indicate that p44/42 MAPK activation is required for interleukin-1beta induction of iNOS and that N-acetyl-L-cysteine may act as a reducing agent and facilitate interleukin-1beta-induced iNOS expression through a reduction/oxidation-related mechanism involving potentiation of cytokine activation of the p44/42 MAPK signaling pathway.     

Mitogen-activated protein kinase and nuclear factor kappaB together regulate interleukin-17-induced nitric oxide production in human osteoarthritic chondrocytes: possible role of transactivating factor mitogen-activated protein kinase-activated proten kinase (MAPKAPK).

OBJECTIVE: To explore the signaling pathways by which the proinflammatory cytokine interleukin-17 (IL-17) may contribute to cartilage catabolism in osteoarthritis (OA) by inducing inducible nitric oxide synthase (iNOS) expression in chondrocytes. METHODS: We examined the IL-17-induced NO production in human OA chondrocytes, in combination with the proinflammatory cytokines IL-1beta, tumor necrosis factor alpha (TNF alpha), and leukemia inhibitory factor (LIF); the antiinflammatory cytokines IL-4, IL-10, and IL-13; and IL-1 receptor antagonist (IL-1Ra). Further, we explored the major intracellular signaling pathways through which IL-17 induced iNOS expression and NO production. RESULTS: Treatment with IL-17 induced a dose-dependent increase in the level of NO. When IL-17 was combined with the above factors, it resulted in a synergistic effect with TNF alpha, an additive effect with LIF, and no further effect than when used alone with IL-1beta. IL-4, IL-10, IL-13, and IL-1Ra had no true effect on IL-17-induced NO production. The cAMP mimetics, 3-isobutyl-1-methyl xanthine plus forskolin, completely blocked IL-17-induced NO production. KT-5720, genistein, and Calphostin C, inhibitors of protein kinase A (PKA), tyrosine kinase, and protein kinase C, respectively, reduced the IL-17-induced NO production by 72%, 56%, and 42%, respectively. Within minutes, IL-17 induced the phosphorylation of mitogen-activated protein kinase kinase-1/2 (MEK-1/2), -3/6 (MKK-3/6), p44/42, p38, and inhibitor of nuclear factor kappaB (I kappaB)-alpha, as well as the activation of mitogen-activated protein kinase-activated protein kinase-1 and -2 (MAPKAPK-1 and -2). Interestingly, IL-17 induced phosphorylation of the stress-activated protein kinase/Jun N-terminal kinase (SAPK/JNK) (p54/46) only when PKA was inhibited. Specific protein kinase inhibitors for MEK-1/2 (PD98059), p38 (SB202190), and nuclear factor kappaB (NF-kappaB) (pyrrolidine dithiocarbamate) each markedly decreased the IL-17-increased iNOS level and NO production. Inhibiting MAPK, including MEK-1/2 and p38, had no effect on the IL-17-induced activation of IkappaB-alpha, but reversed the IL-17 activation of MAPKAPK-1 and -2, respectively. CONCLUSION: These findings show that the stimulation of NO production by IL-17 is mediated mainly by a complex activation of kinases, especially PKA, NF-kappaB, and MAPK. NF-kappaB appears to require MAPK activation, with downstream activation of MAPKAPK probably acting as a transactivating factor, to induce iNOS expression.     

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。     

Inhibition of non-Ras protein farnesylation reduces in-stent restenosis

Ras has a key role in relation to cell proliferation, survival and migration and requires farnesylation for full activity. The effects of a Ras farnesyl transferase inhibitor, FPT III on human atherosclerotic vascular smooth muscle (VSM) cells proliferation and p42/p44 mitogen-activated protein kinase (p42/p44 MAPK) activity was measured. In addition the ability of FPT III to modify the development of neointimal growth was tested in cultured human arteries and in a rabbit model of in-stent restenosis. In human VSM cells FPT III (25 microM) inhibited FCS-stimulated cell proliferation through a ras-dependent mechanism (after 18 h exposure) and also a novel ras-independent mechanism (following 15 min exposure). FPT III incubation (18 h) inhibited platelet-derived growth factor (PDGF)-stimulated p42/p44 MAPK activation and p21 Ras membrane localization, whereas 15 min incubation had no effect on the activation of p42/p44 MAPK in response to PDGF (added at 18 h) or on membrane p21 Ras localization (measured at 18 h). In cultured human atherosclerotic arteries, the presence of 25 microM FPT III significantly reduced neointimal growth. In vivo, 15 min local infusion of 25 microM FPT III significantly reduced in-stent restenosis 28 days later without affecting vascular function in normal rabbit artery. This study demonstrates that brief administration of a farnesyl transferase inhibitor reduced in-stent restenosis in a rabbit model without deleterious effects on vascular function or endothelial regrowth. Acute application of FPT III was found to act through a novel mechanism to inhibit smooth muscle cell proliferation via a non-ras pathway, which may contribute to the prevention of in-stent restenosis.