Gremlin promotes vascular smooth muscle cell proliferation and migration

Recent reports highlight the importance of BMP in the vasculature. We investigated the expression pattern and role of the BMP antagonist gremlin in VSMC. We detected gremlin mRNA constitutive expression in adult and embryonic rat aortic VSMC, and in rat carotids. In vitro analysis demonstrated that angiotensin II, TGF-β1 and PDGF induced significant changes in gremlin mRNA expression. Gremlin stable overexpression in A7r5 cells blocked BMP signaling. BMP-induced reduction in VSMC DNA synthesis was markedly inhibited by gremlin overexpression. In fact, gremlin overexpression increased DNA synthesis and cell counts, and accelerated cell cycle progression of VSMC, through mechanisms that include p27^kip1 down-regulation. Gremlin also led to marked increments in VSMC migration. In addition, gremlin gene silencing promoted a significant blockade on cell proliferation and migration. In vivo studies disclosed increased gremlin protein expression in the neointima of balloon-injured carotid arteries. In summary, the BMP antagonist gremlin is constitutively expressed in the normal vasculature. Gremlin induces VSMC proliferation and migration and is significantly regulated by growth factors and injury. We postulate that gremlin plays a part in the development of pathological phenotypic changes of adult VSMC.     

Inflammatory stimuli upregulate Rho-kinase in human coronary vascular smooth muscle cells

Recent studies have demonstrated that upregulated Rho-kinase plays an important role in the pathogenesis of arteriosclerosis and vasospasm in both animals and humans. However, little is known about the molecular mechanism(s) involved in the Rho-kinase upregulation. Since inflammatory mechanisms have been implicated in the pathogenesis of arteriosclerosis and vasospasm, we examined whether inflammatory stimuli upregulate Rho-kinase in vitro and in vivo. In cultured human coronary vascular smooth muscle cells (hcVSMC), inflammatory stimuli, such as angiotensin II and interleukin-1beta, increased Rho-kinase expression (at both mRNA and protein levels) and function (as evaluated by the extent of the phosphorylation of the ERM (the ezrin/radixin/moesin) family, substrates of Rho-kinase) in a time- and concentration-dependent manner. The expression of Rho-kinase was inhibited by blockades of protein kinase C (PKC) (by either GF109253 or prolonged treatment with phorbol myristate acetate for 24 h) and an adenovirus-mediated gene transfer of dominant-active Ikappa-B, suggesting an involvement of PKC and NF-kappaB in the intracellular signal transduction pathway for the Rho-kinase expression. Furthermore, coronary vascular lesion formation (characterized by medial thickening and perivascular fibrosis) induced by a long-term administration of angiotensin II was markedly suppressed in NF-kappaB(-/-) mice with reduced expression and activity of Rho-kinase in vivo. These results indicate that the expression and function of Rho-kinase are upregulated by inflammatory stimuli (e.g. angiotensin II and IL-1beta) in hcVSMC with an involvement of PKC and NF-kappaB both in vitro and in vivo.     

Circulating soluble LR11, a novel marker of smooth muscle cell proliferation,is enhanced after coronary stenting in response to vascular injury

Objective

Restenosis after vascular intervention remains a major clinical problem. Circulating LR11 has been shown a novel marker of intimal smooth muscle cell (SMC) proliferation in human and animal studies. The present study was performed to clarify the clinical significance of circulating LR11 in patients with stable angina pectoris after coronary stenting.

Methods and results

We firstly investigated the circulating sLR11 levels for 28 days after arterial injury in mice, and then assessed time-dependent change in circulating sLR11 level after coronary stenting in a clinical study. Mouse sLR11 levels rapidly increased to 4.0-fold of the control value without cuff placement at postoperative day (POD) 14, and the levels gradually declined to 3.1-fold of the control value until POD 28 in mice. The circulating soluble LR11 levels were measured (before and at 14, 60 and 240 days after coronary stenting in a clinical study of 102 consecutive patients with stable angina pectoris who were treated with percutaneous coronary intervention. Circulating sLR11 levels were significantly increased on days 14 and 60 after the procedure and positively associated with the angiographic late loss index.

Conclusions

Our study suggested that circulating sLR11 levels may be a potential marker for angiographic late loss in patients after coronary stenting. Further mechanistic studies are expected to know the clinical significance of sLR11 as a novel marker for intimal SMC.     

血管去内皮损伤后平滑肌细胞凋亡的实验观察

目的 了解血管去内皮损伤后新内膜形成及平滑肌细胞(SMCs)凋亡的时相变化。方法用氮气干燥剥脱大鼠颈动脉内皮复制血管损伤模型,HE染色光镜形态计量内膜/中膜比(I/M),末端脱氧核苷酸转移酶(TdT)介导的荧光素d-uTP缺口末端标记(TRNEL)方法观察不同时间新内膜形成(I/M)及VSMC凋亡。结果 血管去内皮后四天,在SMCs增生形成的新内膜中有TUNEL法证实的细胞凋亡,I/M加比,凋亡指数(TUNELI)分别为0.12±0.06,2.4±1.98。在七天,内膜明显增厚(I/M为0.6±0.15,与四天比,P<0.05),TUNELI达到最大值(为9.3±3.8,与四天比,P<0.05)。到第14天,内膜明显增厚约为中膜的1.25倍(I/M比1.25±0.14,与七天比,P<0.05),TUNELI逐渐减小(为8.75±4.01;与七天比,P>0.05)。损伤后21天,内膜开始变薄(I/M比为0.98±0.41,与14天比,P<0.05),凋亡水平进一步下降(TUNELI为6.58±3.97,但差异无显著性,P=NS)。结论 血管壁对损伤刺激诱发增生反应的同时激活凋亡机制。凋亡调节血管壁细胞数和内膜增厚演变。细胞凋亡的平衡失调可能是动脉粥样硬化(AS)、再狭窄(RS)等血管疾病发生的机制之一。     

葛根素对血管平滑肌细胞增殖及增殖细胞核抗原和凋亡抑制蛋白表达的影响

目的:通过观察葛根素对培养的脐动脉平滑肌细胞增殖细胞核抗原(PCNA)和凋亡抑制蛋白(Survivin)表达的影响,探讨葛根素抑制平滑肌细胞增殖的机制。方法:分离培养人脐动脉平滑肌细胞,加入不同浓度葛根素与细胞孵育,采用免疫组化法检测血管平滑肌细胞的PCNA表达;提取RNA,采用Rt-PCR检测Survivin表达水平,并经核苷酸序列分析验证,灰度扫描测定Survivin/GAPDH(s/G)比率。结果:葛根素抑制血管平滑肌细胞的PCNA表达(P=0.0000);葛根素组Survivin/磷酸甘油醛脱氢酶(GAPDH)(s/G)比率较对照组低。结论:葛根素具有抑制血管平滑肌细胞增殖的作用。     

The essential role of p21 in radiation-induced cell cycle arrest of vascular smooth muscle cell

The biologic mechanisms for the success and failure of intravascular radiation therapy after angioplasty have not been well studied. We investigated the molecular mechanism of radiation-induced cell cycle arrest in vascular smooth muscle cell (VSMC) and examined whether p21 knock-out is a cause of radiation failure. Using different dosages of gamma radiation, we evaluated the effect of radiation on VSMC apoptosis and cell cycle progression, and its action mechanism. Irradiation significantly retarded the growth of cultured VSMC, which was not due to induction of apoptosis but mainly due to cell cycle arrest. Radiation showed remarkable cell cycle arrest at G1 and G2 phase (G0/G1:S:G2/M phases = 61%:34%:5% with 0 Gy versus 61%:9%:30% with 16 Gy, 12 h after radiation). In immunoblot analysis and kinase assay, radiation increased the expression of p21 and decreased the expression and activity of CDK2 and 1. In contrast, radiation did not affect the expression and activity of CDK4 and 6, nor the expression of p27 and p16. When p21 was knocked out, cell cycle of VSMC was not arrested by radiation, leading to increased proliferation. These finding provide the evidence that radiation inhibits VSMC proliferation through cell cycle arrest by enhancing p21 expression and suppressing CDK1 and 2. This observation supports the key role of p21 in radiation-induced cell cycle arrest and the degree of p21 expression may be the possible mechanism of radiation failure and delayed restenosis.     

microRNA在动脉硬化闭塞症中调控血管平滑肌的作用机制

动脉硬化闭塞症已成为周围血管疾病的首要病症,严重危害人们身心健康,早期诊断及治疗尤为迫切和必要。近年来,随着非蛋白机制和转录后机制研究的逐渐清晰,部分研究聚焦于探索microRNA与动脉硬化闭塞症之间的关系。文章依据microRNA在动脉硬化闭塞症细胞模型、动物模型和患者水平中调控血管平滑肌细胞的增殖、迁移、分化、表型转换和凋亡等方面来进行学习和研究。microRNA的研究从基因调控方面更好地解释了动脉硬化闭塞症的发生与发展,但由于其中复杂的调控机制以及缺乏药代学和药效学研究数据、作用靶基因众多等因素,其临床应用仍然受到制约。展望未来,应用microRNA治疗药剂治疗血管疾病特别是下肢动脉硬化闭塞症将有效减少其带来的损害。     

阿托伐他汀对大鼠主动脉平滑肌细胞钙化的抑制作用

目的研究阿托伐他汀对体外大鼠主动脉平滑肌细胞钙化(VSMC)的作用。方法采用组织块培养法体外培养大鼠主动脉平滑肌细胞。细胞分5组,即正常组(常规细胞培养液)、钙化组(加入10 mmol／Lβ-磷酸甘油、1×10-7mol／L胰岛素及50μg／L维生素C钙化培养基)和阿托伐他汀(1μmol／L、5μmol／L和10μmol／L)组,后者在诱导血管平滑肌细胞钙化之前,分别给予阿托伐他汀1μmol／L、5μmol/L、10μmol／L预处理24 h后,再加入钙化培养基诱导细胞钙化,连续培养14 d。细胞爬片茜素红S染色观察VSMC钙化;比色法测定细胞Ca2+浓度和细胞蛋白质含量,两者之比作为细胞钙沉积含量;比色法测定细胞ALP活力;MTT法检测细胞增殖。结果阿托伐他汀各组钙结节计数减少,细胞钙沉积含量减少,ALP活力和细胞增殖均降低,并呈剂量依赖性。结论阿托伐他汀对大鼠主动脉平滑肌细胞体外钙化有抑制作用。     

血管平滑肌细胞自噬与血管钙化关系的研究进展

细胞自噬是细胞利用溶酶体进行自身降解的生物学过程,是一种进化上高度保守的分解代谢过程,对于维持细胞稳态起着重要作用。血管钙化是广泛存在于动脉粥样硬化、糖尿病、终末期肾病等多种疾病中的共同病理表现,是影响心血管疾病死亡率的独立危险因素,目前尚缺乏有效的治疗手段。近年来发现血管平滑肌细胞(VSMCs)自噬可通过调节其降解活动及平滑肌细胞的成骨样分化,从而在调控血管钙化中发挥重要作用。本文就VSMCs自噬与血管钙化的最新研究进展做一综述。     

高氟致血管内皮损伤及动脉硬化的病理形态学实验研究

目的应用新西兰白兔高氟模型,观察高氟对动脉血管内皮细胞损伤及致动脉硬化的病理学变化。方法 20只健康雄性新西兰白兔随机分为对照组,饮去离子水,饲基础饲料;高脂组,饮去离子水,饲基础饲料加0.5%胆固醇、7%蛋黄粉的高脂饲料;高氟组,饮含氟离子100mg/L高氟水,饲基础饲料;高氟高脂组,饮含氟离子100mg/L高氟水,饲基础饲料加0.5%胆固醇、7%蛋黄粉的高脂饲料。实验期6个月。于实验前、实验3、6个月取血测血氟含量;实验6个月取血测血脂、脂蛋白含量,取胸主动脉,观察主动脉病理及超微结构变化情况。结果新西兰白兔饮用高氟水6个月建立高氟模型,血氟升高,同时血胆固醇（TC）、甘油三脂（TG）;载脂蛋白低密度脂蛋白（LDL-c）升高;病理检测高氟白兔主动脉管壁弹性降低,主动脉内皮细胞结构以及细胞走向发生改变,有大量红细胞及纤维素沉着并存在少量脂滴。结论高氟引发兔机体脂质代谢紊乱;损伤主动脉内皮细胞,造成细胞结构异常,由此导致动脉硬化形成,在此过程中高氟与高脂具有一定协同作用。     

吡格列酮对瘦素诱导的血管平滑肌细胞PCNA及瘦素受体表达的影响

观察吡格列酮对瘦素诱导的血管平滑肌细胞(VSMCs)增殖的干预作用,分别检测VSMCs中增殖细胞核抗原(PCNA)和瘦素受体(OB-R)mRNA和蛋白表达水平的变化.结果 表明吡格列酮可抑制瘦素刺激的VSMCs增殖以及PCNA和OB-R的表达,抑制效应的最佳浓度为100 μmol/L(P<0.01).     

Myeloid lineage of high proliferative potential human smooth muscle outgrowth cells circulating in blood and vasculogenic smooth muscle-like cells in vivo

Emerging experimental data supports a circulating precursor origin for some smooth muscle cells that participate in vasculogenesis but uncertainty exists on the precise phenotype and lineage of these vascular precursors. We determined the lineage of human smooth muscle outgrowth cells (SOC) derived from circulating blood mononuclear cells and smooth muscle-like cells present in regions of vasculogenesis in diseased arteries. Immunophenotypic characterization of SOC was performed using FACS and immunofluorescence (IF). An SOC hierarchy was determined based on in vitro clonogenic and proliferative potential. Lineage of smooth muscle-like cells in vasculogenic regions in vivo was also determined by dual IF for myeloid and smooth muscle specific markers combined with FISH for the X and Y chromosome in diseased vessel of human subjects who had undergone gender mismatched cardiac transplantation. We show here that primary high proliferative potential smooth muscle outgrowth cells (HPP-SOC) expanded in culture from human peripheral blood mononuclear cells (PBMC) and recipient-derived chimeric smooth muscle cells participating in vasculogenesis in vivo share a myeloid phenotype (CD68 and CD14 positivity). Moreover, HPP-SOC in vitro are distinct in being negative for several myeloid markers such as CD11b, CD13 and CD33, and CD45 surface antigens and chimeric SMC in vivo show no evidence of cell fusion propensity. This study provides evidence of a possible myeloid subpopulation origin for smooth muscle outgrowth cells in blood and vasculogenic smooth muscle-like cells in the intima and adventitial microvasculature of diseased arteries. These data have significant implications for understanding the role myeloid cells play in smooth muscle cell biology and vascular remodelling.     

同型半胱氨酸促血管平滑肌细胞增殖的机制

目的　研究同型半胱氨酸 (HCY)对血管平滑肌细胞 (VSMC)细胞周期、细胞周期素和 P2 7蛋白表达的影响。方法　用流式细胞技术测定细胞周期、细胞周期素和 P2 7蛋白表达量。结果　 HCY促进 VSMC增殖和细胞 S期合成 ,同时使细胞周期素 D、E、A表达明显增加 ,P2 7蛋白表达下降。结论　 HCY促进 VSMC增殖和细胞 S期合成可能是通过增加细胞周期素 D、E、A的表达 ,抑制 VSMC中 P2 7蛋白的表达来实现的。     

球囊扩张术对血管平滑肌细胞COX-2表达的影响及其增殖凋亡分子机制研究

目的研究球囊扩张术后血管平滑肌细胞(VSMC)中环氧化酶2(COX-2)mRNA表达及选择性COX-2抑制剂处理VSMC后,细胞周期蛋白D1(Cyclin D1)、凋亡蛋白Bcl-2的变化,明确COX-2表达与VSMC增殖凋亡分子机制的相关性。方法用RT-PCR检测20只兔腹主动脉球囊拉伤前后VSMC中COX-2的mRNA表达水平；体外实验将选择性COX-2抑制剂NS-398,作用于兔VSMCs,运用MTF法分别于0,24h,48h,72h检测细胞增殖状态；流式细胞仪观察NS-398对细胞凋亡的影响,进一步采用Western blot检测药物作用前后Cyclin D1、Bcl-2的表达。结果兔腹主动脉球囊拉伤后VSMC COX-2mRNA的表达水平明显高于正常VSMC(P＜0．01),为正常组2．42倍；对照组S及G2/M期DNA百分含量与处理组比值分别为1．31,1．62(P＜0．01),NS-398呈时间、剂量依赖性方式抑制VSMC增殖,促进其凋亡。同时,72h时空白组与NS-398(75μmol/L)处理组Cyclin D1、Bcl- 2表达水平比值分别为2．37和3．81(P＜0．01),故两者表达水平随作用时间延长而下降。结论COX-2在球囊扩张术后血管平滑肌细胞中高表达可能在VSMC过度增殖、凋亡受阻中起重要作用。选择性COX-2抑制剂NS-398可能通过Cyclin D1,Bcl-2影响VSMC的增殖与凋亡,提示COX-2抑制剂可作为预防血管成形术后再狭窄新的候选药物。     

高迁移率族蛋白1及其受体促进人主动脉血管平滑肌细胞增殖及迁移的作用研究

目的研究高迁移率族蛋白1(HMGB1)及其受体对体外人主动脉血管平滑肌细胞(VSMC)增殖及迁移的影响。方法体外培养人VSMC株,50、100、200μg/L HMGB1作用细胞24 h后,CCK法检测VSMC的增殖情况;细胞划痕修复及Transwell小室实验检测VSMC迁移情况;Real-time PCR及Western blot检测细胞晚期糖基化终产物受体(RAGE)干扰效率;CCK法及Transwell小室实验检测沉默RAGE后HMGB1对细胞增殖及迁移的影响;Western blot检测核因子(NF-κB)蛋白表达水平。结果 HMGB1作用VSMC后可明显促进细胞增殖及迁移(P0.05);转染si RNA-RAGE后,RAGE的m RNA及蛋白表达水平明显下降(P0.05);与HMGB1组相比,si RNA-RAGE可抑制HMGB1诱导的细胞增殖、迁移及NF-κB蛋白表达(P0.05)。结论 HMGB1可促进VSMC增殖及迁移,机制可能与HMGB1和RAGE结合后激活NF-κB表达有关。     

Gamma-interferon regulates vascular smooth muscle proliferation and Ia antigen expression in vivo and in vitro

A significant fraction of the arterial smooth muscle cells in atherosclerotic plaques and injury-induced intimal thickenings express class II major histocompatibility complex (Ia) antigens. This might be the consequence of gamma-interferon secretion by T lymphocytes also present in these lesions. We have therefore analyzed the effects of gamma-interferon on cultured rat aortic smooth muscle cells. Recombinant gamma-interferon inhibited smooth muscle proliferation in vitro in a dose-response relation; inhibition was detectable down to a concentration of 1 unit/ml. In similar concentrations, gamma-interferon also induced Ia expression by the cells. This suggested that Ia antigens might be selectively expressed by nonproliferating smooth muscle cells. In vivo, there was a strong negative correlation between Ia expression and 3H-thymidine labeling of smooth muscle cells in intimal thickenings induced by balloon catheter injury. In rats receiving continuous infusions of 3H-thymidine for two weeks after injury, Ia-positive 3H-positive cells had undergone fewer rounds of replication than Ia-negative ones. This indicates that Ia-expression both in vivo and in vitro is associated with a reduced proliferative capacity. These results suggest that gamma-interferon, a secretory product of activated T lymphocytes, acts as a natural regulator of smooth muscle cell growth and Ia expression in injury-induced intimal thickenings and atherosclerotic plaques.