阿魏酸钠抑制内皮素-1介导高血压病血管平滑肌细胞增殖的研究

目的研究阿魏酸钠(SF)对高血压痛患者血管平滑肌细胞(VSMC)在体外培养条件下内皮素-1(ET-1)介导增殖的影响.方法采用体外培养的VSMC,选用3～8代VSMC分为:ET-1组;SF组;ET-1与SF组.在ET-1组中加入6个不同浓度的SF(0,20,40,80,100,120μg/ml),培养24h后用苔酚蓝法(MTT)和氚-胸腺嘧啶核苷(3H-TdR)掺入法测定细胞含量及其培养液中一氧化氮(NO).结果SF可使细胞MTT含量和3H-TdR掺入量明显减少,ET-1可使细胞MTT含量和3H-TdR掺入量明显增加.同时,SF可使ET-1所致的细胞MTT含量增加和3H-TdR掺入量增加明显减少,并随SF含量增加而NO升高.结论SF可抑制VSMC增殖,SF抑制ET-1诱导VSMC增殖,并呈剂量依赖型.其作用可能与通过拮抗ET-1、增高NO活性有关.     

Mac-1 and Fas activities are concurrently required for execution of smooth muscle cell death by M-CSF-stimulated macrophages

OBJECTIVE: We have previously shown that macrophage colony stimulating factor (M-CSF), a potent survival and mitogenic factor for monocytes/macrophages (MM), enables MM to induce vascular smooth muscle cell (VSMC) apoptosis. The killing requires the binding of MM to VSMC via Mac-1 (CD11b/CD18) on MM and intracellular adhesion molecule-1 (ICAM-1) on VSMC. We hypothesized that, in addition to Mac-1 binding, the killing process requires the activation of the Fas-death receptor pathway, which can be blocked at the level of Fas-Fas ligand interaction. METHODS AND RESULTS: Human peripheral blood monocytes and VSMC were isolated and cultured as previously described. Soluble Fas (sFas) was overexpressed in VSMC by transduction using adenovirus specifying soluble Fas (Ad3hsFas). M-CSF markedly increased the expression of ICAM-1 in VSMC, resulting in enhanced clustering of MM on the surface of VSMC (>/=3 MM per VSMC). MM, but not VSMC, expressed Fas-ligand (FasL), and VSMC apoptosis was inhibited by secretion of sFas by VSMC upon Ad3sFas transduction. CONCLUSIONS: MM and M-CSF-induced VSMC killing requires MM binding to VSMC mediated by Mac-1 and ICAM-1, and Fas-FasL interaction.     

Cross-linking of brain endothelial intercellular adhesion molecule (ICAM)-1 induces association of ICAM-1 with detergent-insoluble cytoskeletal fraction

Intercellular adhesion molecule (ICAM)-1 plays a vital role in the process of leukocyte transmigration through endothelial cell (EC) barriers and has been shown to mediate signal transduction events in ECs induced either by its cross-linking or by the binding of T lymphocytes. Immunoblotting of ICAM-1 of Triton X-100 detergent fractions demonstrated that the majority of ICAM-1 was contained within the detergent-soluble fraction (noncytoskeletal associated) under basal conditions. After cross-linking of endothelial ICAM-1 with monoclonal antibody or coculture with T lymphocytes, EC ICAM-1 was observed to partition with a Triton X-100-insoluble (cytoskeletal associated) fraction in a dose- and time-dependent manner. Redistribution of ICAM-1 was specific, inasmuch as no association with the Triton X-100-insoluble fraction was observed after cross-linking of vascular cell adhesion molecule-1, nor did cross-linking of ICAM-1 result in a redistribution of the platelet and EC adhesion molecule. ICAM-1 association with the endothelial cytoskeleton after cross-linking was unaffected after treatment of the cells with cytochalasin D, C3-transferase, removal of extracellular calcium ions, or chelation of intracellular calcium ions. These data show that ICAM-1 colocalizes with the endothelial cytoskeleton and associates with a detergent-insoluble fraction after cross-linking.     

Phosphatidylinositol 3-kinase is required for insulin-like growth factor-I-induced vascular smooth muscle cell proliferation and migration

Insulin-like growth factor-I (IGF-I) plays an important role in regulating vascular smooth muscle cell (VSMC) proliferation and directed migration. The mitogenic and chemotactic actions of IGF-I are mediated through the IGF-I receptor, but how the activation of the IGF-I receptor leads to these biological responses is poorly understood. In this study, we examined the role of phosphatidylinositol 3-kinase (PI3 kinase) in mediating the mitogenic and chemotactic signals of IGF-I. IGF-I treatment resulted in a significant increase in phosphotyrosine-associated PI3 kinase activity in cultured primary VSMCs. To determine whether insulin receptor substrate (IRS)-1, -2, or both are involved in IGF-I signaling in VSMCs, cell lysates were immunoprecipitated with either an anti-IRS-1 or an anti-IRS-2 antibody, and the associated PI3 kinase activity was determined. IGF-I stimulation resulted in a significant increase in IRS-1- but not IRS-2-associated PI3 kinase activity, suggesting that IGF-I primarily utilizes IRS-1 to transmit its signal in VSMCs. The IGF-I-induced increase in IRS-I-associated PI3 kinase activity was concentration dependent. At the maximum concentration (50 ng/mL), IGF-I induced a 60-fold increase. This activation occurred within 5 minutes and was sustained at high levels for at least 6 hours. IGF-I also caused a concentration-dependent and long-lasting activation of protein kinase B (PKB/Akt). Inhibition of PI3 kinase activation by LY294002 or wortmannin abolished IGF-I-stimulated VSMC proliferation and reduced IGF-I-directed VSMC migration by approximately 60%. These results indicate that activation of PI3 kinase is required for both IGF-I-induced VSMC proliferation and migration.     

基质相互作用分子1基因敲除抑制血管平滑肌细胞增殖

目的探讨基质相互作用分子1(STIM1)基因敲除对血管平滑肌细胞内钙浓度和细胞增殖的调控作用。方法原代培养血管平滑肌细胞,用构建好的大鼠 STIM1干扰腺病毒载体(Ad-si/rSTIM1)和人重组 ST1M1腺病毒载体(Ad-hSTIM1)进行转染,Western blot 检测细胞 STIM1表达,~3H 胸腺嘧啶核苷(~3H-TdR)掺入法和细胞计数测定细胞增殖,激光共聚焦检测细胞内钙变化。结果 Ad-si/rSTIM1转染后48h 后细胞 STIMl表达与转染对照腺病毒载体比较明显降低(P<0.05),细胞内钙浓度也明显下降(P<0.05),细胞增殖被显著抑制(P<0.05);Ad-hSTIM1共转染后48 h 细胞 STIM1表达恢复到正常水平;细胞内钙浓度和细胞增殖恢复到正常水平。结论 STIM1调节血管平滑肌细胞内钙浓度,并进而参与对血管平滑肌细胞增殖的调控。     

Regulation of ICAM-1-mediated fibroblast-T cell reciprocal interaction: implications for modulation of gut inflammation.

BACKGROUND & AIMS: Immune-nonimmune cell interactions modulate mucosal immunity. We investigated the expression of adhesion molecules by intestinal fibroblasts, the effect of immune cell-derived factor on fibroblast binding of T cells, and the consequences of interfering with adhesion molecule expression on fibroblast-T cell interaction. METHODS: Expression of fibroblast intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 surface and messenger RNA (mRNA) was measured before and after exposure to immune cell-derived supernatants. Fibroblasts were treated with antibodies to ICAM-1 or VCAM-1, or ICAM-1 antisense oligonucleotide Isis 2302, before a T-cell adhesion assay. RESULTS: Fibroblast activation by immune cell-derived cytokines enhanced ICAM-1 and VCAM-1 surface expression and mRNA as well as adhesiveness for T cells. Blockade with neutralizing antibodies showed that binding was almost exclusively dependent on ICAM-1. Isis 2302 specifically reduced fibroblast ICAM-1 mRNA and dose-dependently inhibited ICAM-1 surface expression and T-cell binding. CONCLUSIONS: ICAM-1 is essential for intestinal fibroblast binding of T cells, a phenomenon that is efficiently and specifically disrupted by ICAM-1 antisense oligonucleotides. These observations emphasize the crucial regulatory role of fibroblasts in mucosal immunity and their potential as targets for therapeutic intervention in intestinal inflammation.     

Thrombospondin-1 antagonizes nitric oxide-stimulated vascular smooth muscle cell responses

OBJECTIVE: Endothelial-derived nitric oxide (NO), by increasing cGMP, is a major physiological regulator of vascular tone and of vascular smooth muscle cell (VSMC) adhesion, chemotaxis, and proliferation. Thrombospondin-1 is a potent antagonist of NO/cGMP signaling in endothelial cells. Because endothelial and VSMC typically exhibit opposing responses to thrombospondin-1, we examined thrombospondin-1 effects on NO signaling in VSMC. METHODS: Effects of exogenous thrombospondin-1 on human VSMC adhesion, chemotaxis, proliferation, and cGMP signaling were examined. Endogenous thrombospondin-1 function was characterized by comparing NO signaling in VSMC from wild type and thrombospondin-1 null mice. RESULTS: Picomolar concentrations of exogenous thrombospondin-1 prevented adhesive, chemotactic, and proliferative responses of human aortic VSMC stimulated by low dose NO. A recombinant CD36-binding domain of thrombospondin-1 or antibody ligation of CD36 similarly inhibited NO-stimulated VSMC responses. Thrombospondin-1 and CD36 ligation inhibited NO responses in VSMC by preventing cGMP accumulation. Thrombospondin-1 null VSMC responses to NO and cGMP signaling were enhanced relative to wild type murine VSMC. CONCLUSIONS: In the presence of NO, thrombospondin-1 is converted from a weak stimulator to a potent inhibitor of VSMC responses. Both exogenous and endogenous thrombospondin-1 inhibit NO signaling in VSMC. This activity is mediated by the type 1 repeats and utilizes the same CD36-dependent cGMP signaling pathway in endothelial and VSMC.     

Decreased caveolin-1 in atheroma: loss of antiproliferative control of vascular smooth muscle cells in atherosclerosis

OBJECTIVE: Proliferation of vascular smooth muscle cells (VSMC) is involved in the pathogenesis of primary atherosclerosis and restenosis after angioplasty. On the background of the antiproliferative activities of caveolin-1, the present study focused on the expression of caveolin-1 in proliferating VSMC of human atheroma. METHODS: VSMC were isolated from wild-type (Wt) and caveolin-1 knockout mice (Cav-/-). Proliferation of Wt-VSMC after supplementation of serum or Cav-/-VSMC after adenoviral overexpression of caveolin-1 was documented by either Western blot analysis of the cyclin-dependent kinase (Cdk) inhibitor p27kip1 and the proliferating cell nuclear antigen (PCNA) or BrdU incorporation. Using immunohistochemistry the proliferation of VSMC derived from atheroma of human carotid vessels as well as the expression of caveolin-1 in these cells were investigated ex vivo. RESULTS: Supplementation of serum to Wt-VSMC resulted in an augmented cell cycle entry and a concomitant decrease of caveolin-1 expression. Inversely, adenoviral overexpression of caveolin-1 in Cav-/-VSMC inhibited cellular proliferation. Corresponding to these in vitro data, the expression of caveolin-1 was significantly decreased in proliferating VSMC of human atheroma. CONCLUSION: The proliferation of VSMC in vitro and in human atheroma is associated with a decrease of caveolin-1 expression. These data suggest that the loss of antiproliferative control by caveolin-1 plays a pivotal role in VSMC proliferation in atherosclerosis.     

Inhibition of vascular smooth muscle cell proliferation by a novel fibroblast growth factor receptor antagonist.

OBJECTIVE: One of the key events in post-angioplasty restenosis is the migration and proliferation of medial smooth muscle cells leading to neo-intima formation. This phase is mediated by several growth factors, mainly platelet-derived growth factor (PDGF), basic fibroblast growth factor (FGF2/bFGF) and heparin-binding epidermal growth factor (HB-EGF). In this study, we have focused on the role of FGF2, which requires heparan sulfate proteoglycans (HSPG) as cofactors for binding and activation of its cell surface tyrosine kinase receptor. The aim of this study was to identify and explore the effect of novel FGF antagonists on vascular smooth muscle cell (VSMC) proliferation. METHODS: We have recently identified a novel class of small, positively charged molecules sharing a porphyrin core as inhibitors of FGF2 and vascular endothelial growth factor (VEGF) activity. Here we investigated the inhibitory effect of these compounds on VSMC proliferation and their effect on heparin-induced FGF receptor activity. RESULTS: We found that these molecules exert a marked inhibitory effect on FGF2-mediated smooth muscle cell (SMC) proliferation, manifested by reduced cell growth and DNA synthesis, which occurred in a dose-dependent manner with an IC(50) of approximately 1 microM of inhibitor. We demonstrate that the molecule, 5, 10, 15, 20-tetrakis (methyl-4-pyridyl)-21H, 23H-porphine tetra-p-tosylate salt (TMPP), inhibits binding of radiolabeled FGF2 to SMCs and to soluble FGF receptor 1 (FGFR1) in a manner that interferes with both ligand and receptor interactions with heparin, thereby blocking growth factor mediated SMC proliferation. CONCLUSION: We have identified an FGF antagonist, which may serve in clinical practice as a preventive measure of restenosis.     

Angiotensin II increases the expression of lectin-like oxidized low-density lipoprotein receptor-1 in human vascular smooth muscle cells via a lipoxygenase-dependent pathway

BACKGROUND: Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a membrane protein that can act as a surface endocytosis receptor for oxidized LDL (ox-LDL). As increased cellular uptake of ox-LDL by macrophages and activated smooth muscle cells may transform these cells into foam cells, potential interactions among LDL oxidation, ox-LDL uptake, and regulators of vascular smooth muscle cell function are of obvious interest. The objective of this study was to examine the effect of angiotensin II (AII) on the expression of LOX-1 and ox-LDL degradation in human vascular smooth muscle cells (VSMC) METHODS: We performed in vitro experiments in a human VSMC line (T/G HA-VSMC) derived from normal aortic VSMC, using standards methods. RESULTS: We found that AII (10(-7) mol/L) increased the expression of LOX-1 (approximately 2.5-fold, P < .0001) in association with higher degradation of ox-LDL by HA-SMC (from 4019 +/- 529 ng/mg cell protein to 6207 +/- 287 ng/mg cell protein; P = .0033). AII also increased the expression of 12-lipoxygenase (12-LO) and 15-lipoxygenase (15-LO) by approximately 2.2-fold (P = .03) and approximately 3-fold (P = .006), respectively. In addition, AII (10(-7) mol/L) increased the release of 12- and 15-hydroxyeicosatetraenoic acid from VSMC within 10 min approximately 3-fold (P = .03) and 50% (P < .05), respectively. CONCLUSIONS: Our study findings provide evidence that angiotensin II upregulates LOX-1 and 12-LO and 15-LO expression in human VSMC, thereby potentially providing mechanisms for both accelerated LDL oxidation within the cell and the internalization of exogenous ox-LDL, two processes that could increase the susceptibility of human VSMC to further transformation into foam cells.     

Synergistic effect of urotensin II with serotonin on vascular smooth muscle cell proliferation.

BACKGROUND: Urotensin II (U-II), the most potent vasoconstrictor, and serotonin (5-HT) are known to play an important role in pulmonary hypertension. However, little is known about the effect of U-II and its interaction with 5-HT on vascular smooth muscle cell (VSMC) proliferation. OBJECTIVE: We assessed the interaction between U-II and 5-HT in inducing VSMC proliferation. METHODS: Growth-arrested rabbit VSMCs were incubated in serum-free medium with different concentrations of U-II and 5-HT. VSMC proliferation was examined by the increase in [3H]thymidine incorporation into DNA and cell number. RESULTS: U-II or 5-HT induced [3H]thymidine incorporation in a dose-dependent manner with a maximal effect at a concentration of 50 nmol/l (161%) or 50 micromol/l (205%), respectively. When added together, low concentrations of U-II (50 nmol/l) and 5-HT (1 micromol/l) interacted synergistically in inducing [3H]thymidine incorporation (382%). These effects on [3H]thymidine incorporation were paralleled by an increase in cell number. The G-protein inactivator GDP-beta-S (100 micromol/l), protein kinase C (PKC) inhibitor Ro31-8220 (0.1 micromol/l), Src family tyrosine kinase inhibitor PP2 (1 micromol/l), and mitogen-activated protein kinase (MAPK) kinase inhibitor PD098059 (10 micromol/l) inhibited the mitogenic effects of U-II and 5-HT and also their interaction in inducing [3H]thymidine incorporation. CONCLUSION: Our results suggest that U-II and 5-HT may induce the synergistic interaction in inducing VSMC proliferation via a G-protein-coupled receptor/PKC/Src tyrosine kinase/MAPK pathway, thus contributing to the relatively rapid development of atherosclerosis in hypertensive vascular disease.     

Cellular adhesion molecules on vascular smooth muscle cells.

Several studies during the last years have shown that, in addition to endothelial cells, vascular smooth muscle cells also express the cellular adhesion molecules ICAM-1 and VCAM-1 in atherosclerosis, restenosis and transplant vasculopathy. In vitro studies have characterized stimulatory and inhibitory factors that regulate the expression of ICAM-1 and VCAM-1 on cultured smooth muscle cells. There is evidence for a role of adhesion molecules on smooth muscle cells for leukocyte accumulation and activation of mononuclear cells. Some recent data suggest that the expression of adhesion molecules on smooth muscle cells are cell cycle-dependent and influence smooth muscle cell proliferation and differentiation. Therefore, ICAM-1 and VCAM-1 on smooth muscle cells may contribute to the inflammatory reaction in the vascular wall and may actively be involved in the progression and stability of atherosclerotic plaques.     

PD098059及N-乙酰半胱氨酸在缓激肽引起血管平滑肌细胞增殖反应中的调节作用

目的 :研究丝裂原活化蛋白激酶 （MAPK ）信号途径在缓激肽 （BK）介导的大鼠血管平滑肌细胞 （VSMC）增殖中的作用。方法 :通过 3H -胸苷 （3H- Td R）掺入率与 SMC3H-亮氨酸掺入率分别反映 VSMC的 DNA代谢与蛋白质合成代谢速率 ;并通过给予 PD0 980 5 9及 N-乙酰半胱氨酸预处理 ,观察其对细胞增殖的影响。结果 :1BK（10 nm ol/L ）处理 30 min,VSMC3H-胸苷掺入率和 3H-亮氨酸掺入率均明显增高 ;2 BK增高 3H -胸苷掺入的作用可明显被PD0 980 5 9所抑制 ,对 3H -亮氨酸掺入的作用可部分被 PD0 980 5 9所抑制 ;3BK增高 3H -胸苷掺入和 3H -亮氨酸掺入的作用均可部分被 N-乙酰所抑制 ,完全被 N-乙酰 +PD0 980 5 9所抑制。结论 :细胞外信号调节激酶 （ERKs）激活在缓激肽介导的 VSMC增殖中具有重要作用 ,并可通过 ERKs信号途径的特异性抑制剂影响血管平滑肌细胞的增殖效应。     

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。     

Functional modulation of smooth muscle cells by the inflammatory mediator CAP37

CAP37, a neutrophil-derived protein, originally identified for its antimicrobial activity is now known to have strong immunoregulatory effects on host cells. Recently, we described its expression and localization within the vascular endothelium associated with atherosclerotic plaques. Since CAP37 is a potent activator of endothelial cells and monocytes, two of the key cellular components of the atherosclerotic plaque, this study was undertaken to determine whether CAP37 had functional effects on smooth muscle cells another important cellular participant in atherosclerosis. Sections from atherosclerotic lesions were stained for the presence of CAP37 and smooth muscle cell alpha actin. The effect of CAP37 on aorta smooth muscle cell migration and proliferation was investigated and the upregulation of adhesion molecules was determined. Immunocytochemistry indicated that CAP37 was present in a subset of smooth muscle cells within atherosclerotic lesions, but was absent in normal vessels. Flow cytometry using double labeling for the proliferation marker Ki-67 and CAP37 demonstrates that CAP37 is mainly expressed in proliferating smooth muscle cells. We show that CAP37 supports migration and proliferation of smooth muscle cells in vitro. Furthermore, CAP37-treated smooth muscle cells expressed higher levels of the cell adhesion molecule ICAM-1 when compared with untreated cells. We suggest that due to its localization to atherosclerotic plaques and its ability to modulate smooth muscle cells, CAP37 may play a role in the progression of this disease.     

Neutrophils infiltrate resistance-sized vessels of subcutaneous fat in women with preeclampsia

We examined if there is systemic vascular inflammation and neutrophil infiltration in women with preeclampsia. Resistance-sized vessels (10 to 200 microm) of subcutaneous fat were evaluated from normal nonpregnant women, normal pregnant women, and preeclamptic women. Immunohistochemical staining was performed for: (1) interleukin-8 (IL-8), a potent neutrophil chemokine; (2) intercellular adhesion molecule-1 (ICAM-1; CD54), an endothelial cell adhesion molecule; and (3) CD66b, a neutrophil antigen. Vessels of preeclamptic patients had intense IL-8 staining in the endothelium and vascular smooth muscle, as compared with little or no staining for normal pregnant and normal nonpregnant patients. ICAM-1 was expressed on the endothelium of all patient groups. In preeclamptic patients, ICAM-1 was also expressed on vascular smooth muscle. Vessels of preeclamptic patients had significantly more CD66b staining of neutrophils than did normal pregnant or normal nonpregnant patients. There were significantly more vessels stained, more vessels with neutrophils flattened and adhered to endothelium, more vessels with neutrophils infiltrated into the intima, and more neutrophils per vessel. In conclusion, in women with preeclampsia, there was significant infiltration of neutrophils into maternal systemic vasculature associated with inflammation of the vascular smooth muscle indicated by increased expression of IL-8 and ICAM-1. Neutrophil infiltration provides a reasonable explanation for endothelial and vascular smooth muscle dysfunction in preeclampsia because neutrophils produce toxic substances, which may explain clinical symptoms.     

Both estrogen and raloxifene cause G1 arrest of vascular smooth muscle cells

The proliferation of vascular smooth muscle cells (VSMC) is a crucial pathophysiological process in the development of atherosclerosis. Although estrogen is known to inhibit the proliferation of VSMC, the mechanism responsible for this effect remains to be elucidated. In addition, the effect of raloxifene on VSMC remains unknown. We have shown here that 17beta-estradiol (E(2)) and raloxifene significantly inhibited the platelet-derived growth factor (PDGF)-stimulated proliferation of cultured human VSMC. Flow cytometry demonstrated that PDGF-stimulated S-phase progression of the cell cycle in VSMC was also suppressed by E(2) or raloxifene. We found that PDGF-induced phosphorylation of retinoblastoma protein (pRb), whose hyperphosphorylation is a hallmark of the G1-S transition in the cell cycle, was significantly inhibited by E(2) and raloxifene. These effects were associated with a decrease in cyclin D1 expression, without a change in cyclin-dependent kinase 4 or cyclin-dependent kinase inhibitor, p27(kip1) expression. ICI 182,780 abolished the inhibitory effects of E(2) and raloxifene on PDGF-induced pRb phosphorylation. Next, we examined which estrogen receptor (ER) is necessary for these effects of E(2) and raloxifene. Since VSMC express both ERalpha and ERbeta, A10, a rat aortic smooth muscle cell line that expresses ERbeta but not ERalpha, was used. The dose-dependent stimulation of A10 cell proliferation by PDGF was not inhibited by E(2) or raloxifene in contrast to the results obtained in VSMC. Moreover, E(2) and raloxifene significantly inhibited the PDGF-induced cyclin D1 promoter activity in A10 cells transfected with cDNA for ERalpha but not in the parental cells. These results suggested that E(2) and raloxifene exert an antiproliferative effect in VSMC treated with PDGF, at least in part through inhibition of pRb phosphorylation, and that the inhibitory effects of E(2) and raloxifene may be mainly mediated by ERalpha.     

Effects of C-reactive protein on human pulmonary vascular cells in chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterised by proximal pulmonary vascular obstruction by thrombo-fibrotic material, the origin of which has not been elucidated. Enhanced inflammation could contribute to persistent obstruction by impairing pulmonary vascular cell function in CTEPH. We investigated C-reactive protein (CRP) effects on pulmonary vascular cell function in vitro. Primary cultures of proximal pulmonary endothelial cells (ECs) and smooth muscle cells (SMCs) from CTEPH and nonthromboembolic pulmonary hypertension (PH) patients were established. Recombinant CRP effects on mitogenic activity, adhesion capacity, endothelin-1 and von Willebrand factor (vWF) secretion and intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule-1 expression were investigated in ECs and/or SMCs. Expression of the CRP receptor, lectin-like oxidised low-density lipoprotein receptor (LOX)-1, was evaluated in proximal pulmonary arterial tissue and cells by Western blotting and immunofluorescence. CRP increased CTEPH-SMC proliferation by 250%. CRP increased adhesion capacity, endothelin-1 and vWF secretion by CTEPH-ECs by 37%, 129% and 694%, respectively. CRP-induced adhesion of CTEPH-ECs to monocytes was mediated by ICAM-1. CRP had no effect on cells from nonthromboembolic PH patients, probably because of overexpression of LOX-1 in CTEPH. Local expression of CRP was detected in ECs and SMCs within pulmonary arterial tissue. CRP may contribute to persistent obstruction of proximal pulmonary arteries in CTEPH by promoting vascular remodelling, endothelial dysfunction and in situ thrombosis.