Angiotensin II and serotonin potentiate endothelin-1-induced vascular smooth muscle cell proliferation

BACKGROUND: Vascular smooth muscle cell (VSMC) proliferation induced by various growth factors has been implicated in a wide variety of pathological processes, including hypertension, atherosclerosis and restenosis after angioplasty. OBJECTIVES: To investigate the interactions among well-known potent vasoconstrictor substances, endothelin-1 (ET-1), angiotensin II (Ang II), and serotonin (5-HT), on VSMC proliferation. METHODS: Growth-arrested rabbit VSMCs were incubated with different concentrations of ET-1 in the absence or presence of Ang II, 5-HT, or both. VSMC proliferation was examined by increases in incorporation of [3H]thymidine into DNA and in cell number. RESULTS: ET-1, Ang II and 5-HT stimulated DNA synthesis in a dose-dependent manner. ET-1 had a maximal effect at a concentration of 0.5 micromol/l (259% of control), Ang II at 1 micromol/l (173%), and 5-HT at 50 micromol/l (205%). When added together, ET-1 (0.1 micromol/l) and Ang II (1 micromol/l) synergistically induced DNA synthesis (341%). When the vasoconstrictors were tested in combination, even non-mitogenic concentrations of ET-1 (0.01 nmol/l) potentiated 5-HT (5 micromol/l)-induced DNA synthesis (404%). Co-incubation of ET-1 (0.01 micromol/l) with Ang II (1 micromol/l) and 5-HT (5 micromol/l) synergistically induced DNA synthesis (566%). These effects on DNA synthesis were paralleled by an increase in cell number. The ETA/B non-selective receptor antagonist, TAK044 (1 micromol/l) and the ETA receptor antagonist, BQ123 (1 micromol/l), but not the ETB receptor antagonist, BQ788 (1 micromol/l), inhibited the mitogenic effect of ET-1 and its interaction with Ang II or 5-HT. In addition, TAK044 (1 micromol/l) or BQ123 (1 micromol/l) along with the angiotensin II type 1 (AT1) receptor antagonist, candesartan (1 micromol/l), the 5-HT2A receptor antagonist, sarpogrelate (10 micromol/l), or both, inhibited the interactions of ET-1 with Ang II or 5-HT. CONCLUSIONS: Our results suggest that Ang II and 5-HT could potentiate ET-1-induced VSMC proliferation. Inhibition of ETA, AT1, and 5-HT2A may be effective in the treatment of VSMC proliferative disorders associated with hypertension, atherosclerosis and restenosis after angioplasty.     

Statins effect on smooth muscle cell proliferation

Clinical trials have firmly established that 3-hydroxy-3-methylglutaryl-coenzyme-A reductase inhibitors (statins) can induce regression of vascular atherosclerosis as well as reduction of cardiovascular-related morbidity and death in patients with and without coronary artery disease. These beneficial effects of statins are usually assumed to result from their ability to reduce cholesterol synthesis. However, because mevalonic acid is the precursor not only of cholesterol but also of many nonsteroidal isoprenoid compounds, inhibition of 3-hydroxy-3-methylglutaryl-coenzyme-A reductase may result in pleiotropic effects. Indeed, statins can interfere with major events involved in the formation and the evolution of atherosclerotic lesions, such as arterial myocyte migration and proliferation and cholesterol accumulation, independent of their hypolipidemic properties. The aim of this article is to focus on clinical and experimental data that show that statins possess effects beyond cholesterol lowering, particularly on arterial smooth muscle cell proliferation. The contribution of these direct vascular effects to the reduction of cardiovascular events observed in clinical trials with statins represents one of the major challenges for future studies to understand the antiatherosclerotic benefits of these agents.     

紫杉醇抑制大鼠血管平滑肌细胞增殖的实验研究

目的 以体外培养的大鼠血管平滑肌细胞为研究对象,探讨紫杉醇对平滑肌细胞增殖的作用.方法 SD大鼠腹腔注射麻醉后,解剖、分离其主动脉,仔细分离血管的平滑肌层并剪成小块置于培养瓶中培养.采用倒置像筹显微镜下观察及α平滑肌肌动蛋白免疫荧光检测对传4代～6代的细胞进行鉴定.根据加入的干预药物将平滑肌细胞分为无血清M199培养基组(A组)、1 nmol/L紫杉醇组(B组)、10 nmol/L紫杉醇组(C组)及100 nmol/L紫杉醇组(D组)共4组,每组均为5个样本.采用流式细胞仪检测不同干预组平滑肌细胞的生长周期,用增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)检测方法 检测细胞的PCNA阳性百分比.结果 培养约2周后出现大量细胞生长,可见致密的细胞层.倒置像差显微镜下观察,细胞呈梭形;随着细胞融合度的增加,可以看到平滑肌细胞特有的"峰-谷"生长现象.培养的血管平滑肌细胞α平滑肌肌动蛋白免疫荧光检测呈阳性,总阳性率大于90%.随着紫杉醇用量的增加,细胞的PCNA阳性百分比呈逐渐减少的趋势,与对照组(A组)比较,10 nmol/L(C组)和100 nmol/L(D组)两种浓度下的紫杉醇引起的PCNA阳性率明显减低.流式细胞仪检测显示,随着紫杉醇用量的增加,细胞S期百分比旱逐渐减少的趋势.与对照组相比,10 nmol/L(C组)和100 nmol/L(D组)两种浓度下的紫杉醇引起的S期百分比明显减低.结论 紫杉醇能够抑制大鼠血管平滑肌细胞的增殖.     

紫杉醇抑制大鼠血管平滑肌细胞增殖的实验研究

目的以体外培养的大鼠血管平滑肌细胞为研究对象,探讨紫杉醇对平滑肌细胞增殖的作用。方法SD大鼠腹腔注射麻醉后,解剖、分离其主动脉,仔细分离血管的平滑肌层并剪成小块置于培养瓶中培养。采用倒置像差显微镜下观察及α平滑肌肌动蛋白免疫荧光检测对传4代～6代的细胞进行鉴定。根据加入的干预药物将平滑肌细胞分为无血清M199培养基组（A组）、1nmol／L紫杉醇组（B组）、10nmol／L紫杉醇组（c组）及100nmol／L紫杉醇组（D组）共4组,每组均为5个样本。采用流式细胞仪检测不同干预组平滑肌细胞的生长周期,用增殖细胞核抗原（proliferating cell nuclear antigen,PCNA）检测方法检测细胞的PCNA阳性百分比。结果培养约2周后出现大量细胞生长,可见致密的细胞层。倒置像差显微镜下观察．细胞呈梭形：随着细胞融合度的增加,可以看到平滑肌细胞特有的“峰-谷”生长现象。培养的血管平滑肌细胞α平滑肌肌动蛋白免疫荧光检测呈阳性,总阳性率大于90％。随着紫杉醇用量的增加,细胞的PCNA阳性百分比呈逐渐减少的趋势,与对照组（A组）比较,10nmol／L（C组）和100nmol／L（D组）两种浓度下的紫杉醇引起的PCNA阳性率明显减低。流式细胞仪检测显示,随着紫杉醇用量的增加,细胞S期百分比呈逐渐减少的趋势。与对照组相比,10nmol／L（C组）和100nmol／L（D组）两种浓度下的紫杉醇引起的S期百分比明显减低。结论紫杉醇能够抑制大鼠向管平滑肌细朐的增殖．     

Serotonin potentiates angiotensin II--induced vascular smooth muscle cell proliferation.

Vascular smooth muscle cell (VSMC) proliferation is a key feature in the development of atherosclerosis and restenosis after angioplasty, which can occur in response to many different humoral and mechanical stimuli. We investigated the growth promoting activities of two potent vasoactive substances, angiotensin II (Ang II) and serotonin (5-HT), on cultured rabbit VSMCs. Growth-arrested VSMCs were incubated with serum-free medium containing different concentrations of Ang II in the presence or absence of 5-HT. [3H]thymidine incorporation into VSMC DNA was measured as an index of cell proliferation. Ang II and 5-HT stimulated DNA synthesis in a dose-dependent manner with a maximal effect at 1.75 microM for Ang II (202%) and 50 microM for 5-HT (205%). When added together, low concentrations of Ang II (1 microM) and 5-HT (5 microM) synergistically induced DNA synthesis (363%). Candesartan (1 microM), an AT(1) receptor antagonist, but not PD 123319 (1 microM), an AT(2) receptor antagonist, inhibited the mitogenic effect on Ang II and its interaction with 5-HT. Sarpogrelate (10 microM), a 5-HT(2A) receptor antagonist, and pertussis toxin (10 ng/ml) inhibited the mitogenic effect of 5-HT and its interaction with Ang II. The protein kinase C inhibitor Ro 31-8220 (0.1 microM), the Raf-1 inhibitor radicicol (10 microM), and the MAPK kinase inhibitor PD 098059 (10 microM) abolished mitogenic effects of Ang II and 5-HT, and also their synergistic interaction. The JAK2 inhibitor AG 490 (10 microM) had only a minimal inhibitory effect of Ang II-induced DNA synthesis but significantly inhibited the interaction of Ang II with 5-HT. The synergistic effect on Ang II (1 microM) with 5-HT (5 microM) on DNA synthesis was completely reversed by the combined use of both candesartan (1 microM) and sarpogrelate (10 microM). Our results suggest that Ang II and 5-HT exert a synergistic interaction on VSMC proliferation via AT(1) and 5-HT(2A) receptors. The activation of MAPK and JAK/STAT pathways may explain the synergistic interaction between Ang II and 5-HT.     

Inhibition of vascular smooth muscle cell proliferation by endothelium-dependent vasodilators.

This review considers the hypothesis that the endothelium-derived vasodilator agents, prostacyclin and nitric oxide, also function physiologically to inhibit vascular smooth muscle cell (VSMC) proliferation. The underlying biochemical mechanisms are also discussed. Prostacyclin and other agents that increase intracellular cAMP concentration are potent and effective inhibitors of the proliferation of isolated VSMC in culture. Such agents inhibit the initiation of proliferation in quiescent cells and the proliferation of logarithmically growing cells from a variety of sources, including man. The data implicate prostacyclin as an important regulator of VSMC proliferation, although there is little direct in vivo evidence. Nitric oxide-releasing drugs (and atriopeptins which increase intracellular cGMP concentration by a different mechanism) also inhibit proliferation of cultured VSMC. The effects are, however, partial and obtained at higher concentrations than those required for vasodilatation. Even allowing for the instability of the agents under tissue culture conditions, cGMP-elevating agents appear to be poorer at inhibiting proliferation than cAMP-elevating agents, despite similar or greater vasodilator potency. These data imply that nitric oxide is less likely than prostacyclin to be a physiological regulator of VSMC proliferation, although definitive experiments in vivo are again lacking. It also follows that nitrovasodilators are less attractive as therapy for VSMC proliferation than prostacyclin analogues or other cAMP-elevating agents, such as phosphodiesterase inhibitors. By analogy with the mechanisms of vasodilatation, inhibition of calcium mobilization and the subsequent activation of protein kinase C are considered as possible mechanisms underlying inhibition of proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lipid peroxidation product 4-hydroxy-2-nonenal acts synergistically with serotonin in inducing vascular smooth muscle cell proliferation

Formation of an atherosclerotic lesion is in part mediated by inflammatory and oxidative mechanisms including lipid peroxidation. To characterize the potential role of lipid peroxidation products in atherogenesis, we assessed the effect of 4-hydroxy-2-nonenal (HNE), a component of oxidatively modified lipids on vascular smooth muscle cells (VSMCs) proliferation, and its interaction with serotonin (5-hydroxytryptamine, 5-HT), a known mitogen for VSMCs. Growth-arrested rabbit VSMCs were incubated with different concentrations of HNE in the absence or presence of 5-HT. VSMCs proliferation was examined by increases in [3H]thymidine incorporation into DNA and cell number. HNE and 5-HT stimulated DNA synthesis in a dose-dependent manner. HNE had a maximal proliferative effect at a concentration of 1 microM (143% of the control) and 5-HT at 50 microM (211%). When added together, low concentrations of HNE (0.1 microM) and 5-HT (5 microM) synergistically induced DNA synthesis (273%). These effects on DNA synthesis were paralleled by an increase in cell number. A 5-HT2 receptor antagonist LY 281067 (10 microg/ml) and pertussis toxin (10 ng/ml) inhibited the mitogenic effect of 5-HT only. Protein tyrosine kinase inhibitor erbstatin A (10 microM) completely inhibited the mitogenic effect of HNE and partially that of 5-HT and the combined effect of HNE+5-HT. Protein kinase C inhibitor Ro 31-8220 (0.1 microM) completely inhibited mitogenic effects of both HNE and 5-HT, and also the combined effect of HNE+5-HT. The synergistic effect of HNE+5-HT on DNA synthesis was completely reversed by the combined use of LY 281067 (10 microg/ml) and antioxidants N-acetylcysteine (400 microM), vitamin C (200 microM), or vitamin E (20 microM). Our results suggest that HNE acts synergistically with 5-HT in inducing VSMCs proliferation. Combined use of both antiplatelet and antioxidant therapies may be useful for the prevention of VSMCs proliferative disorders associated with atherosclerosis and restenosis after angioplasty.     

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.     

同型半胱氨酸促进血管平滑肌细胞增殖的机制及辛伐他汀的干预作用

目的:探讨同型半胱氨酸促进大鼠血管平滑肌细胞(VSMC)增殖的机制及辛伐他汀的干预作用。方法:贴壁培养的大鼠原代VSMC随机分为3组。(1)对照组:用含10%胎牛血清的DMEM培养基(完全培养基);(2)同型半胱氨酸组:在完全培养基中加入同型半胱氨酸(0.05 mmol/L);(3)辛伐他汀组:在完全培养基中加入同型半胱氨酸(0.05 mmol/L)和辛伐他汀(10μmol/L)。培养24 h后,光学显微镜下观察各组细胞的形态;采用半定量PCR法检测c-myc、P27kip1的mRNA水平;用Western blot检测细胞周期蛋白(cyclin)D1、cyclin E、cyclin A和核增殖抗原(PCNA)的蛋白表达水平。结果:与对照组相比,同型半胱氨酸组c-myc mRNA水平上调,P27kip1 mRNA水平下调,下游cyclin D1、cyclin E、cyclin A和PCNA蛋白表达增加。与同型半胱氨酸组相比,辛伐他汀组上述检测指标均得到逆转。结论:同型半胱氨酸可促进大鼠VSMC c-myc、cyclin D1、cyclin E、cyclin A等增殖相关基因的表达,抑制P27kip1表达。辛伐他汀可逆转上述效应。     

Mildly oxidized low-density lipoprotein acts synergistically with angiotensin II in inducing vascular smooth muscle cell proliferation

OBJECTIVES: Considerable attention has been focused on both mildly oxidized low-density lipoprotein (mox-LDL) and highly oxidized LDL (ox-LDL) as important risk factors for cardiovascular disease. Further, angiotensin II (Ang II) appears to play a crucial role in the development of hypertension and atherosclerosis. We assessed the effect of oxidatively modified LDL and its major oxidative components, i.e., hydrogen peroxide (H2O2), lysophosphatidylcholine (LPC), and 4-hydroxy-2-nonenal (HNE) and their interaction with Ang II on vascular smooth muscle cell (VSMC) DNA synthesis. METHODS: Growth-arrested rabbit VSMCs were incubated in serum-free medium with different concentrations of native LDL, mox-LDL, ox-LDL, H2O2, LPC, or HNE with or without Ang II. DNA synthesis in VSMCs was measured by [3H]thymidine incorporation. RESULTS: Ang II stimulated DNA synthesis in a dose-dependent manner with a maximal effect at a concentration of 1 micromol/l (173%). Ang II (0.5 micromol/l) amplified the effect of native LDL at 500 ng/ml, ox-LDL at 100 ng/ml, and mox-LDL at 50 ng/ml on DNA synthesis (108 to 234%, 124 to 399%, 129 to 433%, respectively). H2O2 had a maximal effect at a concentration of 5 micromol/l (177%), LPC at 15 micromol/l (156%), and HNE at 0.5 micromol/l (137%). Low concentrations of H2O2 (1 micromol/l), LPC (5 micromol/l), or HNE (0.1 micromol/l) also acted synergisitically with Ang II (0.5 micromol/l) in inducing DNA synthesis to 308, 304, or 238%, respectively. Synergistic interactions of Ang II (0.5 micromol/l) with mox-LDL, ox-LDL (both 50 ng/ml), H2O2 (1 micromol/l), LPC (5 micromol/l), or HNE (0.1 micromol/l) on DNA synthesis were completely reversed by the combined use of probucol (10 micromol/l), a potent antioxidant and candesartan (0.1 micromol/l), an AT1 receptor antagonist. CONCLUSIONS: Our results suggest that mox-LDL, ox-LDL, and their major components H2O2, LPC, and HNE act synergistically with Ang II in inducing VSMC DNA synthesis. A combination of antioxidants with AT1 receptor blockade may be effective in the treatment of VSMC proliferative disorders associated with hypertension and atherosclerosis.     

Paracrine effect of human vascular endothelial cells on human vascular smooth muscle cell proliferation: Transmembrane co-culture method

Summary To investigate the role endothelial cells have on underlying smooth muscle cell proliferation, human aortic vascular smooth muscle cells were co-cultured with human aortic endothelial cells at different cell densities, using a transmembrane co-culture method. Subconfluent endothelial cells subseeded at low (0.5 × 10⁴ cells/well) and medium densities (2.0 × 10⁴ cells/well) stimulated smooth muscle cell proliferation by 43 ± 14% (P < 0.01) and 39 ± 8% (P < 0.02), respectively. However, this stimulatory effect on smooth muscle cell proliferation was not evident in confluent endothelial cells subseeded at high cell density (8.0 × 10⁴ cells/well). Treatment of smooth muscle cells with trapidil, at 10^–6M, for anti-platelet derived growth factor (PDGF) effect or with endothelin-1 receptor blocker FR 139317, at 10^–6M failed to inhibit this stimulatory effect. These results imply that subconfluent human endothelial cells are able to exert a stimulatory effect on human smooth muscle cell proliferation, and that this endothelial paracrine growth effect may not be mediated by endothelin or PDGF.     

Mechanisms of telomerase induction during vascular smooth muscle cell proliferation

Telomeres are primarily controlled by a highly specialized DNA polymerase termed telomerase. Recent studies have demonstrated that introduction of the telomerase catalytic component (TERT) into telomerase-negative cells activates telomerase and extends cell life span, whereas mice lacking telomerase activity revealed impaired cell proliferation in some organs as well as reduced tumorigenesis. These reports suggest that telomerase plays an important role in long-term cell viability and cell proliferation. However, the mechanism or mechanisms by which telomerase is induced or regulated remains to be elucidated. We report here that primary vascular smooth muscle cells (VSMCs) express telomerase and that increased telomerase activity correlates with cell proliferation. Inhibition of telomerase diminished growth of VSMCs, which suggests a crucial role for telomerase activation in the regulation of VSMC proliferation. We propose a novel model whereby telomerase is first activated in the cytoplasm before cell proliferation, followed by accumulation of activity in the nucleus during the logarithmic phase of cell growth. Activation of telomerase in VSMCs was linked to phosphorylation of TERT. The protein kinase inhibitor H7 suppressed the activation of telomerase in the cytoplasm and also inhibited the accumulation of TERT as well as telomerase activity in the nucleus. These data suggest that posttranslational modification of TERT by phosphorylation is important for activation and accumulation of telomerase into the nucleus in the process of VSMC proliferation.     

巨噬细胞集落刺激因子与血管平滑肌细胞增殖

目的一些以血管平滑肌细胞（ＶＳＭＣ）增殖为特点的血管疾病，在病变部位常有巨噬细胞浸润。本研究巨噬细胞集落刺激因子（ＭＣＳＦ）在ＶＳＭＣ生长调节中的作用。方法实验采用培养大鼠主动脉ＶＳＭＣ，细胞增殖观察指标采用氚标胸腺嘧啶核苷掺入法，并用Ｎｏｒｔｈｅｒｎｂｌｏｔ技术测定原癌基因表达。结果（１）Ｌ９２９细胞上清液（富含ＭＣＳＦ）及重组ＭＣＳＦ以剂量依赖关系刺激氚标胸腺嘧啶核苷掺入；（２）ＶＳＭＣ在接受刺激后表达某些原癌基因，如ｃｆｏｓ、ｃｍｙｃ、ｅｒｇ１和ＪｕｎＢ；（３）凝血酶、ＰＤＧＦ、ｂＦＧＦ与ＭＣＳＦ在促增殖作用上具有协同作用。结论ＭＣＳＦ与其它生长因子协同作用，通过自分泌／旁分泌机制调控ＶＳＭＣ增殖，从而可能在血管病变的形成和进展中起重要作用     

青蒿素对血管平滑肌细胞增殖的影响

目的 :观察青蒿素 (artemisinin ,Art)对体外培养大鼠主动脉平滑肌细胞 (VSMC)的增殖、DNA合成及细胞周期的影响 ,探讨作用机制。方法 :体外培养大鼠主动脉VSMC ,分为不同浓度的Art组及对照组。观察细胞生长曲线 ;四甲基偶氮唑盐微量酶反应 (MTT)法检测细胞活性 ;3H 胸腺嘧啶脱氧核苷(3H- TdR)掺入法观察其对DNA合成的影响 ;通过HE染色、DNA梯带检测和流式细胞术观察细胞的凋亡并测定细胞周期。结果 :与对照组相比 ,各浓度Art组VSMC计数不同程度减少 ,3H- TdR掺入率降低 ,细胞增殖受抑制 ,VSMC凋亡增加 ,并呈浓度依赖性 ;Art诱导细胞凋亡 ;使细胞周期阻滞于G0 / G1 期。结论 :Art对体外培养VSMC的增殖有抑制作用 ,可能通过抑制细胞DNA合成 ,诱导细胞凋亡及干扰细胞周期等途径发挥作用     

MicroRNA-124抑制大鼠血管平滑肌细胞增殖及分子机制研究

目的探讨MicroRNA-124(miR-124)对大鼠血管平滑肌细胞增殖的作用及可能的调控机制。方法选择10只11周龄雄性SPF级自发性高血压大鼠(SHR)作为实验组及同龄的10只SPF级Wistar大鼠(WKY)为对照组。采用组织贴片法原代培养SHR和WKY主动脉平滑肌细胞。通过实时荧光定量PCR(qRT-PCR)技术检测miR-124在两组主动脉平滑肌细胞间的表达差异。将miR-124模拟物或模拟物阴性对照转染SHR主动脉平滑肌细胞,分析过表达miR-124对血管平滑肌细胞增殖的影响。通过数据库及生物信息学软件预测miR-124的靶基因,并利用双荧光素酶报告基因系统进行验证。通过qRT-PCR和Western blot检测靶基因Meox2 mRNA及蛋白表达变化。采用RNA干扰技术,观察敲低Meox2表达对血管平滑肌细胞增殖的影响。结果 MiR-124在SHR主动脉平滑肌细胞中的表达为WKY主动脉平滑肌细胞的0.22倍(P0.01)。体外过表达miR-124可明显抑制SHR主动脉平滑肌细胞的增殖。经生物信息学分析及体外双荧光素酶报告基因系统检测,证实Meox2是miR-124的靶基因。过表达miR-124后SHR主动脉平滑肌细胞中Meox2 mRNA的表达为阴性对照组的0.29倍(P0.01);Western blot结果显示,Meox2蛋白表达水平亦明显降低。干扰Meox2的表达亦可降低SHR主动脉平滑肌细胞的增殖。结论 MiR-124在SHR中表达下调,其可能通过介导Meox2调控主动脉平滑肌细胞的增殖进而抑制高血压病变的发生过程。     

Galectin 1 is involved in vascular smooth muscle cell proliferation

OBJECTIVE: Smooth muscle cell (SMC) migration and proliferation are the key steps in the development of atherosclerosis and restenosis. Matricellular proteins have been implicated in cell adhesion, migration and proliferation. Here we investigated the role of the matricellular protein galectin-1 (Gal-1), a beta-galactoside-binding lectin, in SMC proliferation in atheroma and DNA synthesis in cell culture. METHODS: Protein expression was visualised by tissue section immunostaining. RNA expression was analysed using Northern blot analysis. DNA synthesis of human vascular SMCs was determined by 3H-thymidine incorporation. Recombinant glutathione S-transferase-galectin-1 fusion protein (Gal FP) binding to extracellular matrix (ECM) proteins was measured by ELISA. Gal-1 binding to cells and ECM was estimated using 125I-labelled Gal FP. RESULTS: Prominent Gal-1 staining coincided with SMC proliferation in human coronary endarterectomy samples in organoid culture. In cell culture, Gal-1 mRNA was upregulated in growing SMCs. Gal FP increased serum-induced DNA synthesis of human SMCs on plastic or endogenous ECM, but not of a rat PAC1 SM cell line. Also, Gal FP slightly increased SMC adhesion to ECM. SMCs exhibited a complex pattern of receptor-ligand interactions with Gal FP. The Gal-1 binding to SMCs was much stronger than to ECM, produced by these SMCs. We identified new ECM proteins: thrombospondin, vitronectin and osteopontin, which bound to Gal FP in a dose- and beta-galactoside-dependent manner in ELISA. CONCLUSIONS: Gal-1 binding to SMCs was stronger than to ECM, although ECM of atherosclerotic blood vessels contained additional ECM proteins which bound to Gal-1. Gal-1 was upregulated during SMC growth and Gal FP enhanced serum-induced DNA synthesis in SMCs. Overall, Gal-1 upregulation is likely to provide a reinforcement of serum-induced events during vascular injury.