Inhibition of vascular smooth muscle cell proliferation in vitro and in vivo by c-myc antisense oligodeoxynucleotides.

Restenosis after angioplasty is due predominantly to accumulation of vascular smooth muscle cells (VSMCs). The resistance of restenosis to pharmacological treatment has prompted investigation of genes involved in VSMC proliferation. We have examined the effect on VSMC proliferation of blocking expression of the c-myc proto-oncogene with antisense oligodeoxynucleotides, both in vitro and in a rat carotid artery injury model of angioplasty restenosis. Antisense c-myc oligodeoxynucleotides reduced average cell levels of c-myc mRNA and protein by 50-55% and inhibited proliferation of VSMCs when mitogenically stimulated from quiescence or when proliferating logarithmically (IC50 = 10 micrograms/ml). Corresponding sense c-myc, two-base-pair mismatch antisense c-myc, antisense alpha-actin or glyceraldehyde phosphate dehydrogenase oligodeoxynucleotides did not suppress c-myc expression or inhibit VSMC proliferation. Antisense c-myc inhibition was relieved by overexpression of an exogenous c-myc gene. After balloon catheter injury, peak c-myc mRNA expression occurred at 2 h. Antisense c-myc applied in a pluronic gel to the arterial adventitia reduced peak c-myc expression by 75% and significantly reduced neointimal formation at 14 d, compared with sense c-myc and gel application alone. We conclude that c-myc expression is required for VSMC proliferation in vitro and in the vessel wall. C-myc is a therefore a potential target for adjunctive therapy to reduce angioplasty restenosis.     

In vivo transfer of human hepatocyte growth factor gene accelerates re-endothelialization and inhibits neointimal formation after balloon injury in rat model

Although most therapeutic strategies to prevent restenosis are designed to inhibit vascular smooth muscle cell (VSMC) proliferation directly, VSMC proliferation might be indirectly inhibited by re-endothelialization, as endothelial cells secrete antiproliferative and antithrombotic substances. We hypothesized that application of an endothelium-specific growth factor to balloon-injured arteries could accelerate re-endothelialization, thereby attenuating intimal hyperplasia. In this study, we investigated in vivo gene transfer of human HGF that exclusively stimulated endothelial cells without replication of VSMC growth into injured vessels. Transfection of human HGF gene into rat balloon-injured carotid artery resulted in significant inhibition of neointimal formation up to at least 8 weeks after transfection, accompanied by detection of human immunoreactive HGF. Induction of re-endothelialization induced by overexpression of human HGF gene transfer into balloon-injured vessels is supported by several lines of evidence: (1) Administration of HGF vector. but not control vector, markedly inhibited neointimal formation, accompanied by a significant increase in vascular human and rat HGF concentrations. (2) Planimetric analysis demonstrated a significant increase in re-endothelialized area in arteries transfected with human HGF vector. (3) Induction of NO content in balloon-injured vessels transfected with human HGF vector was observed in accordance with the recovery of endothelial vasodilator properties in response to acetylcholine. As endogenous HGF expression in balloon-injured vessels was significantly decreased as compared with normal vessels, the present study demonstrated the successful inhibition of neointimal formation by transfection of human HGF gene as 'cytokine supplement therapy' in a rat balloon injury model.     

血管内皮损伤后血管平滑肌细胞增殖的机制

目的 探讨血管内皮损伤后血管平滑肌细胞增殖的机制。方法 建立颈动脉血管内皮损伤的大鼠模型，行光镜和电镜观察；采用免疫组织化学法检测增殖细胞核抗原（PCNA）、Ⅰ型胶原和Ⅳ型胶原；采用原位杂交法检测成纤维细胞生长因子（FGF）、血小板源生长因子（PDGF）、Bcl-2、Bax和c-myc的表达并行TUNEL染色。结果 内皮损伤后血管管腔面积减少，平滑肌细胞（VSMC）增殖并呈激活状态细胞凋亡减少。PCNA、Ⅰ型胶原、Ⅳ胶原、PDGF、FGF、Bcl-2和c-myc的表达增高。而Bax表达降低。结论 血管内皮损伤后血管平滑肌细胞的迁移、增殖、凋亡及细胞外基质的分泌和堆积，受到多种细胞因子、生长因子和基因调控的介导，参与了局部血管重建和再塑过程。     

Adenovirus-mediated over-expression of the cyclin/cyclin-dependent kinase inhibitor, p21 inhibits vascular smooth muscle cell proliferation and neointima formation in the rat carotid artery model of balloon angioplasty.

Vascular smooth muscle cell (VSMC) proliferation after arterial injury is important in the pathogenesis of a number of vascular proliferative disorders, including atherosclerosis and restenosis after balloon angioplasty. Thus, a better understanding of the molecular mechanisms underlying VSMC proliferation in response to arterial injury would have important therapeutic implications for patients with atherosclerotic vascular disease. The p21 protein is a negative regulator of mammalian cell cycle progression that functions both by inhibiting cyclin dependent kinases (CDKs) required for the initiation of S phase, and by binding to and inhibiting the DNA polymerase delta co-factor, proliferating cell nuclear antigen (PCNA). In this report, we show that adenovirus-mediated over-expression of human p21 inhibits growth factor-stimulated VSMC proliferation in vitro by efficiently arresting VSMCs in the G1 phase of the cell cycle. This p21-associated cell cycle arrest is associated both with significant inhibition of the phosphorylation of the retinoblastoma gene product (Rb) and with the formation of complexes between p21 and PCNA in VSMCs. In addition, we demonstrate that localized arterial infection with a p21-encoding adenovirus at the time of balloon angioplasty significantly reduced neointimal hyperplasia in the rat carotid artery model of restenosis. Taken together, these studies demonstrate the important role of p21 in regulating Rb phosphorylation and cell cycle progression in VSMC, and suggest a novel cytostatic gene therapy approach for restenosis and related vascular proliferative disorders.     

miRNA-146a调控血管平滑肌细胞增殖和凋亡的作用及机制

目的探究miRNA-146a调控血管平滑肌细胞增殖、凋亡的作用及相关机制。方法取SDP级健康雄性SD大鼠作为实验对象,取血管平滑肌细胞(VSMC)消化离心后,转染50nmol/L miRNA-146a反义寡核苷酸、错义链和同等剂量磷酸盐缓冲液(PBS),进行对照比较。结果实验组细胞在转染后48h内VSMC的数目和吸光度值均低于其他两组,细胞凋亡率明显高于其他两组,核因子κBp65、PCNA的表达水平低于其他两组,差异均具有统计学意义(P0.05)。结论miRNA-146a可促进VSMC的增殖,抑制细胞凋亡的进行,这一作用机制与核因子κBp65、PCNA表达水平增高有关。     

过氧化氢酶过度表达对血管平滑肌细胞增殖的影响

目的:探讨腺病毒载体介导的过氧化氢酶基因转染对体外培养的人血管平滑肌细胞增殖的影响。方法:用含过氧化氢酶基因的重组腺病毒(AdCat)转染人血管平滑肌细胞,应用四甲基偶氮唑蓝(MTT)方法观察血管平滑肌细胞的增殖活性,同时用流式细胞术观察血管平滑肌细胞细胞周期的变化。结果:MTT比色法分析显示AdCat组明显抑制细胞增殖,与对照组相比差异有显著性(P<0.05);细胞周期分析发现AdCat组G0/G1期分布百分率显著高于对照组,而S、G2/M期分布百分率显著低于对照组,细胞增殖能力下降(P<0.05)。结论:腺病毒载体介导的过氧化氢酶基因转染能抑制人血管平滑肌细胞的增殖。     

Oxido-reductive regulation of vascular remodeling by receptor tyrosine kinase ROS1

Angioplasty and stenting is the primary treatment for flow-limiting atherosclerosis; however, this strategy is limited by pathological vascular remodeling. Using a systems approach, we identified a role for the network hub gene glutathione peroxidase-1 (GPX1) in pathological remodeling following human blood vessel stenting. Constitutive deletion of Gpx1 in atherosclerotic mice recapitulated this phenotype of increased vascular smooth muscle cell (VSMC) proliferation and plaque formation. In an independent patient cohort, gene variant pair analysis identified an interaction of GPX1 with the orphan protooncogene receptor tyrosine kinase ROS1. A meta-analysis of the only genome-wide association studies of human neointima-induced in-stent stenosis confirmed the association of the ROS1 variant with pathological remodeling. Decreased GPX1 expression in atherosclerotic mice led to reductive stress via a time-dependent increase in glutathione, corresponding to phosphorylation of the ROS1 kinase activation site Y2274. Loss of GPX1 function was associated with both oxidative and reductive stress, the latter driving ROS1 activity via s-glutathiolation of critical residues of the ROS1 tyrosine phosphatase SHP-2. ROS1 inhibition with crizotinib and deglutathiolation of SHP-2 abolished GPX1-mediated increases in VSMC proliferation while leaving endothelialization intact. Our results indicate that GPX1-dependent alterations in oxido-reductive stress promote ROS1 activation and mediate vascular remodeling.     

辛伐他汀含药血清对兔血管平滑肌细胞增殖及原癌基因表达的作用及意义

目的　探讨辛伐他汀对体外培养兔血管平滑肌细胞 (VSMC)增殖的影响及机制。方法　 16只雄性新西兰兔随机分为空白血清对照组和 3个不同剂量的辛伐他汀组 (5mg/kg、10mg/kg、15mg/kg) ,7d后采血并混合每组 4只兔血 ,无菌分离制备分组辛伐他汀含药血清。另采用内皮素 1刺激原代培养正常喂饲兔主动脉VSMC建立增殖模型 ,采用MTT及3 H TdR法检测分组辛伐他汀含药血清对VSMC增殖的作用 ,采用免疫细胞化学方法检测VSMCc myc、c fos抗原表达、RT PCR半定量检测c myc及c fosmRNA表达。结果　与对照组相比 ,不同分组辛伐他汀含药血清呈剂量依赖性抑制血管平滑肌细胞增殖 (P <0 0 5～ 0 0 1) ;免疫细胞化学及RT PCR结果表明 ,不同分组辛伐他汀含药血清呈剂量依赖方式抑制VSMCc fos和c mycmRNA表达(P <0 .0 5～ 0 .0 1)。结论　兔口服辛伐他汀后的血清抑制VSMC增殖 ,而辛伐他汀含药血清抑制c fos和c myc表达可能是其抑制VSMC增殖和抗动脉粥样硬化的机制之一。     

内皮型一氧化氮合酶基因转染对血管损伤后新生内膜增生的影响

背景：一氧化氮能够抑制血管平滑肌细胞的迁移和增殖,而一氧化氮合酶是其合成的关键酶,有关一氧化氮合酶基因体内转染对平滑肌细胞及动脉粥样硬化血管损伤后内膜增生影响少有报道。目的：观察内皮型一氧化氮合酶（endothelial nitric oxide synthase,eNOS）基因体内局部转染对动脉粥样硬化大鼠血管损伤后新生内膜增生的抑制作用。方法：建立动脉粥样硬化Wistar大鼠颈动脉球囊损伤模型,建模后随机分成空白对照组、AdCMV-lacz对照组和AdCMV-eNOS组,分别将PBS,AdCMV-lacz和AdCMV-eNOS体内转染至以上3组大鼠的损伤血管壁。转染2周后培养并鉴定损伤局部平滑肌细胞,并用RT-PCR法检测各组损伤及转染后血管平滑肌细胞eNOS mRNA的表达,同时观察转染后不同时期新生内膜增生的影响。结果与结论：AdCMV-eNOS组的颈总动脉血管平滑肌细胞可表达eNOS mRNA。3组大鼠转染后1和3个月,AdCMV-eNOS组内膜/中膜面积比值低于空白对照组和AdCMV-lacz对照组（P〈0.01）。结果显示,eNOS基因体内转染损伤后血管可以抑制血管新生内膜增生,减少再狭窄发生率。     

Taxol inhibits neointimal smooth muscle cell accumulation after angioplasty in the rat.

Despite significant improvements in the primary success rate of the medical and surgical treatments for atherosclerotic disease, including angioplasty, bypass grafting, and endarterectomy, secondary failure due to late restenosis continues to occur in 30-50% of individuals. Restenosis and the later stages in atherosclerotic lesions are due to a complex series of fibroproliferative responses to vascular injury involving potent growth-regulatory molecules (such as platelet-derived growth factor and basic fibroblast growth factor) and resulting in vascular smooth muscle cell (VSMC) proliferation, migration, and neointimal accumulation. We show here, based on experiments with both taxol and deuterium oxide, that microtubules are necessary for VSMCs to undergo the multiple transformations contributing to the development of the neointimal fibroproliferative lesion. Taxol was found to interfere both with platelet-derived growth factor-stimulated VSMC migration and with VSMC migration and with VSMC proliferation, at nanomolar levels in vitro. In vivo, taxol prevented medial VSMC proliferation and the neointimal VSMC accumulation in the rat carotid artery after balloon dilatation and endothelial denudation injury. This effect occurred at plasma levels approximately two orders of magnitude lower than that used clinically to treat human malignancy (peak levels achieved in this model were approximately 50-60 nM). Taxol may therefore be of therapeutic value in preventing human restenosis with minimal toxicity.     

内皮型一氧化氮合酶基因转染对血管损伤后新生内膜增生的影响

背景:一氧化氮能够抑制血管平滑肌细胞的迁移和增殖,而一氧化氮合酶是其合成的关键酶,有关一氧化氮合酶基因体内转染对平滑肌细胞及动脉粥样硬化血管损伤后内膜增生影响少有报道。目的:观察内皮型一氧化氮合酶(endothelial nitric oxide synthase,eNOS)基因体内局部转染对动脉粥样硬化大鼠血管损伤后新生内膜增生的抑制作用。方法:建立动脉粥样硬化Wistar大鼠颈动脉球囊损伤模型,建模后随机分成空白对照组、AdCMV-lacz对照组和AdCMV-eNOS组,分别将PBS,AdCMV-lacz和AdCMV-eNOS体内转染至以上3组大鼠的损伤血管壁。转染2周后培养并鉴定损伤局部平滑肌细胞,并用RT-PCR法检测各组损伤及转染后血管平滑肌细胞eNOS mRNA的表达,同时观察转染后不同时期新生内膜增生的影响。结果与结论:AdCMV-eNOS组的颈总动脉血管平滑肌细胞可表达eNOS mRNA。3组大鼠转染后1和3个月,AdCMV-eNOS组内膜/中膜面积比值低于空白对照组和AdCMV-lacz对照组(P<0.01)。结果显示,eNOS基因体内转染损伤后血管可以抑制血管新生内膜增生,减少再狭窄发生率。     

Novel and effective gene transfer technique for study of vascular renin angiotensin system.

Vascular renin angiotensin system (RAS) has been reported to exist in vascular wall. However, there is no direct evidence whether the vascular RAS per se can modulate growth of vascular smooth muscle cells (VSMC), because there is no suitable method to investigate the effect of endogenously produced vasoactive substances on growth of these cells. In this study, we transferred angiotensin-converting enzyme (ACE) and/or renin cDNAs into cultured VSMC using the efficient Sendai virus (hemagglutinating virus of Japan) liposome-mediated gene transfer method, to examine their relative roles in VSMC growth in vitro. Within 35 min or 6 h, the transfection of ACE cDNA into VSMC by hemagglutinating virus of Japan method resulted in a twofold higher ACE activity than control vector, whereas a cationic liposome (Lipofectin)-mediated method failed to show any effect. This in vitro system provided us with the opportunity to investigate the influence of endogenous vascular RAS on VSMC growth. Transfection of ACE or renin cDNA resulted in increased DNA and RNA synthesis, which was inhibited with the specific angiotensin II receptor antagonist (DuP 753: 10(-6) M). Angiotensin I added to ACE-transfected VSMC increased RNA synthesis in a dose-dependent manner. Cotransfection of renin and ACE cDNAs stimulated further RNA synthesis as compared to ACE or renin cDNA alone. These results showed that transfected components of RAS can modulate VSMC growth through the endogenous production of vascular angiotensin II, and that ACE as well as renin are rate limiting in determining the VSMC RAS activity. We conclude that the hemagglutinating virus of Japan liposome-mediated gene transfer technique provides a new and useful tool for study of endogenous vascular modulators such as vascular RAS.     

Evidence for direct local effect of angiotensin in vascular hypertrophy. In vivo gene transfer of angiotensin converting enzyme.

In vitro studies have demonstrated that angiotensin (Ang) II directly stimulates vascular smooth muscle cell (VSMC) growth. However, it is still unclear if Ang II exerts a direct effect on vascular hypertrophy in vivo independent of its effect on blood pressure. In vivo gene transfer provides the opportunity to assess the effects of increased activity of the vascular angiotensin system in the intact animal while avoiding an increase in circulating angiotensin or in blood pressure. Accordingly, we transfected the human angiotensin converting enzyme (ACE) vector into intact rat carotid arteries by the hemagglutinating virus of Japan-liposome method. 3 d after transfection, we detected increased ACE activity in the transfected artery. Immunohistochemistry localized immunoreactive ACE in the medial VSMC as well as in the intimal endothelial cells. The increase in vascular ACE activity was associated with a parallel increase in DNA synthesis as assessed by BrdU (bromo-deoxyuridine) index and vascular DNA content. This increase in DNA synthesis was abolished by the in vivo administration of an Ang II receptor-specific antagonist (DuP 753). Morphometry at 2 wk after transfection revealed an increase in the wall to lumen ratio of the ACE-transfected blood vessel as compared with control vector transfected vessels. This was accompanied by increases in protein and DNA contents without an increase in cell number. Local transfection of ACE vector did not result in systemic effects such as increased blood pressure, heart rate, or serum ACE activity. These morphological changes were abolished by the administration of the Ang II receptor antagonist. In this study, we used in vivo gene transfer to increase local expression of vascular angiotensin converting enzyme and provided proof that increased autocrine/paracrine angiotensin can directly cause vascular hypertrophy independent of systemic factors and hemodynamic effects. This approach has important potentials for defining the role of autocrine/paracrine substances in vascular biology and hypertension.     

MiRNA-146a对血管平滑肌细胞凋亡的抑制作用

目的观察miRNA-146a对血管平滑肌细胞凋亡的作用并研究其机制。方法原代培养大鼠血管平滑肌细胞，分成inhibitor组、control组和normal组，采用脂质体2000分别转染miRNA-146ainhibitors（50μM）、错义链（50μM）、PBS，realtimePCR测定转染后miRNA-146a水平，流式细胞仪检测转染后血管平滑肌细胞凋亡，western blot检测转染后Bax蛋白水平。结果转染48h后，inhibitor组血管平滑肌细胞的miRNA-146a水平明显低于normal和control组（P〈O．01），inhibitor组血管平滑肌细胞的凋亡显著高于normal、control组（P〈0．05），且Bax蛋白表达水平增加（P〈O．05）。结论miRNA-146a可以抑制血管平滑肌细胞的凋亡，其机制与抑制Bax表达相关。     

Peroxisome proliferator-activated receptor ligands affect growth-related gene expression in human leukemic cells

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated nuclear receptors. Three subtypes of PPARs (alpha, beta, and gamma) have been identified in different tissues. PPAR alpha and PPAR gamma ligands inhibit cell proliferation and induce differentiation in several human cell models. We demonstrated that both PPAR alpha (clofibrate and ciprofibrate) and PPAR gamma ligands (troglitazone and 15 deoxy-prostaglandin J2, 15d-PGJ2) inhibited growth, induced the onset of monocytic-like differentiation, and increased the proportion of G0/G1 cells in the HL-60 leukemic cell line. Moreover, 3 days after the treatment with 2.5 microM 15d-PGJ2, an increase in sub-G0/G1 population occurred, compatible with an induction of programmed cell death. To clarify the mechanisms involved in HL-60 growth inhibition due to the effects of PPAR ligands, we investigated their action on the expression of some genes involved in the control of cell proliferation, differentiation, and cell cycle progression such as c-myc, c-myb, and cyclin D1 and D2. Clofibrate (50 microM), ciprofibrate (50 microM), and 15d-PGJ2 (2.5 microM) inhibited c-myb and cyclin D2 expression, whereas they did not affect c-myc and cyclin D1 expression. Only troglitazone (5 microM) decreased c-myc mRNA and protein levels, besides decreasing c-myb and cyclin D2. The down-regulations of c-myb and cyclin D2 expression represent the first evidence of the inhibitory effect exerted by PPAR ligands on these genes. Moreover, the inhibition of c-myc expression by troglitazone may depend on a PPAR-independent mechanism.