Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent studies have shown that the presence of tumor suppressors such as p53 or p16 account for the lack of transformation in primary cells. To investigate a potential role of active Ras in atherosclerosis, we infected bovine aortic endothelial cells with a replication-deficient, recombinant adenovirus containing the activated H-Ras61L gene. Ras overexpression led after 72 hours to G1- and G2/M-cell cycle arrest due to induction of p21(Cip1/Waf1). Treatment of Ras-infected endothelial cells with 40 ng/ml TNF-alpha for 20 hours augmented apoptosis 8-fold in comparison to Ad-Con (control virus with empty expression cassette) infected cells (36.2% vs. 4.3%, p < 0.001), while Ras itself did not cause any cell death. Furthermore, more than 58% of Ras-infected cells stained positive for senescence-associated beta-galactosidase activity as opposed to 2% in control vector-infected cells (p < 0.001), strongly suggesting a senescent phenotype in the Ras-infected population. We found further features of senescence in Ras-transduced endothelial cells, such as growth arrest and the lack of AP-1 serum inducibility. Finally, we evaluated the role of p21(Cip1/Waf1) in this process of senescence. Adenoviral overexpression of p21 led to growth arrest by induction of G1- and G2/M-cell cycle arrest. In addition, p21-overexpressing endothelial cells were highly sensitive for TNF-alpha induced-apoptosis. Surprisingly, senescence-associated beta-galactosidase activity was not apparant in p21-infected endothelial cells, suggesting further signaling events necessary for the senescent morphology of endothelial cells. Our results demonstrate a novel way to render primary endothelial cells senescent by overexpressing oncogenic Ras. Increased sensitivity of senescent endothelial cells for cytotoxic stimuli seemed to be due to Ras-induced upregulation of p21(Cip1/Waf1). Future studies have to investigate a potential role of Ras in human vascular biology.
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PMID:Oncogenic ras induces premature senescence in endothelial cells: role of p21(Cip1/Waf1). 1200 58

Vascular smooth muscle cell (VSMC) proliferation after arterial injury is playing a pivotal role in the pathogenesis of a number of vascular proliferative disorders including atherosclerosis and restenosis after balloon-mediated angioplasty. Thus, a better understanding of the molecular mechanisms underlying VSMC proliferation in response to injury would have important therapeutic implications. Cell proliferation is controlled by an intricate network of extracellular and intracellular signaling pathways which are processing various growth regulatory signals and integrating them into the basic cell-cycle regulatory machinery through control of cyclin dependent kinases (CDK). CDK are positively regulated by cyclins and negatively regulated by CDK inhibitory proteins (CKI). To dissect the role of CKI in VSMC proliferation, we prepared the replication-deficient adenovirus constructs expressing p21 family members (Ad-CKI), p21Waf1, p27Kip1 and p57Kip2, respectively, and investigated the effect of CKI overexpression on the proliferation of vascular smooth muscle cells. The overexpression of each CKI protein in cultured VSMC was confirmed by western blot analysis. Flowcytometric analysis revealed that the Ad-CKI infected VSMC were largely retained in G1 phase, and had significantly less G2/M fraction than control cells. The extent of DNA synthesis in VSMC was assessed by [3H]-thymidine uptake, and shown to be inhibited by Ad-CKI dose dependently. Among three CKIs tested in this study, p57Kip2 showed the most significant suppression of DNA synthesis. In order to investigate in vivo effect of p57Kip2 overexpression, Ad-p57 was locally delivered to the luminal wall of rabbit carotid arteries after balloon angioplasty. Histological examinations revealed that the local infection of Ad-p57 significantly suppressed the neointimal formation at the site of vascular injury. These results clearly demonstrated the antiproliferative role of p57Kip2 in VSMC, and also proposed a possibility of gene therapy approach for vascular proliferative disorders.
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PMID:Adenovirus-mediated overexpression of a cyclin-dependent kinase inhibitor, p57Kip2, suppressed vascular smooth muscle cell proliferation. 1205 49

Reactive oxygen species formation by phagocytes and subsequent modifications of vascular wall are involved in the early step of human atherogenesis. This study looked for the effect of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors on NADPH oxidase-dependent superoxide anion production in THP-1 cells, a monocyte-derived cell line, and on the translocation of p21 Rac 2 and p67. A 30-min incubation with simvastatin (50 micro M ) inhibited phorbol 12-myristate 13-acetate-induced superoxide anion production by monocytes (32%) and a maximum inhibition was obtained at 3 h of incubation (69.5%). In addition, after 3 h of incubation a dose-dependent inhibition was obtained in the range 10-50 micro M of simvastatin with a median inhibitory concentration of 36 +/- 2.3 micro M Mevalonic acid (100 and 300 micro M ) and geranylgeraniol (100 micro M ) totally prevented the simvastatin-induced inhibitory effect of superoxide production by monocytes whereas farnesyl PP (100 micro M ) partially prevented (50%) this effect. In addition, simvastatin inhibited the translocation of p21 rac 2 and p67, suggesting that geranylgeranylation is required for NADPH oxidase activation. In another set of experiments, the rank order of potency of different statins on NADPH oxidase was determined (pravastatin < cerivastatin < lovastatin < fluvastatin < simvastatin). In conclusion, inhibition of superoxide formation by HMG CoA reductase inhibitors is highly suitable to prevent or limit the oxidative stress involved in the atherosclerosis process.
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PMID:Statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, are able to reduce superoxide anion production by NADPH oxidase in THP-1-derived monocytes. 1235 24

Abnormal vascular smooth muscle (VSM) cell proliferation contributes to the development of atherosclerosis and its associated disorders, including angioplasty restenosis. The tumor-suppressor protein p53 has been linked to the development of atherosclerotic lesions, and its homolog, p73, is proving to have contrasting functions in a variety of tissues. As an outgrowth of our previous finding that p73 is increased in serum-stimulated VSM cells and human atherosclerotic tissue, we examined p73 overexpression in VSM cells to elucidate causality of p73 expression with growth response. Overexpression of p73 results in decreased cell cycle transit and is accompanied by apoptosis. The apoptotic changes in p73 overexpressing VSM cells are independent of p53 and are associated with a decrease in levels of p21(waf1/cip1). In conjunction with our previous data finding that p73 is increased in serum-stimulated VSM cells, this work suggests a role for p73 in vascular proliferative diseases.
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PMID:Overexpression of p73 causes apoptosis in vascular smooth muscle cells. 1238 4

Neointima formation, the leading cause of restenosis after catheter angioplasty, is a paradigm for vascular proliferative responses. Neointima formation is self-limiting after a variable degree of tissue growth, causing significant renarrowing in a substantial number of patients. To investigate the mechanisms that limit neointima formation we studied the role of the transcription factor IRF-1, which is a regulator of interferons and a tumor suppressor. We demonstrate that IRF-1 is highly regulated in human vascular lesions and exhibits a growth inhibitory function in coronary artery smooth muscle cells (CASMC). IRF-1 deficient mice display a high grade of susceptibility towards neointima formation following vessel injury. IRF-1 leads to G(1) cell cycle arrest in CASMC and induces the CDK inhibitor p21. In addition, IRF-1 induces NO production, which is known to attenuate endothelial dysfunction. Mitogen-mediated cellular migration is abrogated by IRF-1. In conclusion, IRF-1 displays pleiotropic anti-restenotic activities in vascular restenosis through transcriptional activation of several relevant mechanisms that limit neointima formation. These findings suggest an important role of this transcription factor as an endogenous inhibitor of neointimal growth following vessel injury and it is likely that IRF-1 regulation also plays a role in the pathophysiology of primary atherosclerosis. In addition, IRF-1 may be an interesting target for interventions to prevent neointimal hyperplasia.
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PMID:A central role of interferon regulatory factor-1 for the limitation of neointimal hyperplasia. 1249 98

Oxidized low-density lipoprotein (oxLDL) may be involved in atherosclerosis by stimulating proliferation of cells in the vessel wall. The purpose of this study was to identify the mechanism by which oxLDL induces proliferation. Quiescent human fibroblasts and rabbit smooth muscle cells were treated with 0, 10, or 50 microg/ml oxLDL for 24-48 h. This resulted in significant increases in total cell counts at both concentrations of oxLDL, at both time points, for both types of cells. Western blot analysis revealed that oxLDL-stimulated cell proliferation was associated with significant increases in the expression of proteins that regulate entry into and progression through the cell cycle [cell division cycle 2, cyclin-dependent kinase (cdk) 2, cdk 4, cyclin B1, cyclin D1, and PCNA]. Surprisingly, the expression of cell cycle inhibitors (p21 and p27) was stimulated by oxLDL as well, but this was to a lesser extent than the effects on cell cycle-activating proteins. OxLDL also induced nuclear localization of all cell cycle proteins examined. The similar effects of oxLDL on the translocation and expression of both cell cycle-activating and -inhibiting proteins may explain the controlled proliferative phenomenon observed in atherosclerosis as opposed to the more rapid proliferative event characteristic of cancer.
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PMID:OxLDL stimulates cell proliferation through a general induction of cell cycle proteins. 1252 57

Two phenotypes of rat carotid arterial smooth muscle cells (SMC) have been isolated in our laboratory, and their proteolytic and anti-proteolytic activities have been investigated in the presence or absence of various stimulating agents. We report here a comparative study of the cytotoxic effects of nitric oxide (NO) donors, sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP), towards the swirling-type and the epithelioid-type SMCs. The concentration- and time-dependence of NO donors' capacity to induce cell deaths was measured by an intracellular acid phosphatase activity assay and cell counting. The typical morphological features of apoptosis, such as cell blebbing and cytoplasm condensation, were observed by phase contrast microscopy and with a fluorescent DNA-binding dye. Apoptotic cell deaths were confirmed using DNA fragmentation and terminal deoxyribonucelotidyl transferase-mediated dUTP nick end labelling (TUNEL) methods. Western blots were used to investigate the protein expression of several known mediators of apoptosis. It was found that both NO donors induced cell deaths in the SMC phenotypes. Compared to the swirling SMCs, the epithelioid SMCs were much more sensitive to these agents. A time- and dose-dependent decrease of cell viability was observed at NO donor concentrations higher than 0.2 mmol/l. Microscopic methods revealed cell morphology of apoptotic cell deaths. The 180-bp DNA multimers typical of apoptosis were shown by DNA fragmentation. TUNEL technique confirmed that apoptosis occurred most readily in the epithelioid SMCs than the swirling SMCs. When epithelioid SMCs were treated with SNP, changes in p53, p21(WAF1), Bcl-2, caspase 3 and PARP protein expression were found. These protein levels were unchanged when swirling SMCs were similarly treated.
Atherosclerosis 2003 Feb
PMID:Cytotoxicity of nitric oxide donors in smooth muscle cells is dependent on phenotype, and mainly due to apoptosis. 1253 34

Epidemiological studies have shown that a diet rich in fruits and vegetables might reduce the risk of cardiovascular diseases and protect against cancer by mechanisms that have not been elucidated yet. This study was aimed to define the effect of delphinidin, a vasoactive polyphenol belonging to the class of anthocyanin, on bovine aortic endothelial cells (BAECs) proliferation. Delphinidin inhibited serum- and vascular endothelium growth factor-induced BAECs proliferation. This antiproliferative effect of delphinidin, is triggered by ERK-1/-2 activation, independent of nitric oxide pathway and is correlated with suppression of cell progression by blocking the cell cycle in G(0)/G(1) phase. Furthermore, suppression of cell cycle progression is associated with the modulation of the mitogenic signaling transduction cascade. This includes over-expression of caveolin-1 and p21(WAF1/Cip1) and down-expression of Ras and cyclin D1. In conclusion, the antiproliferative effect of delphinidin may be of importance in preventing both plaque development and stability in atherosclerosis and tumor dissemination in cancer.
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PMID:Delphinidin inhibits endothelial cell proliferation and cell cycle progression through a transient activation of ERK-1/-2. 1256 96

Abnormal vascular smooth muscle cell (VSMC) proliferation plays an important role in the pathogenesis of both atherosclerosis and restenosis. Recent studies suggest that high-dose salicylates, in addition to inhibiting cyclooxygenase activity, exert an antiproliferative effect on VSMC growth both in-vitro and in-vivo. However, whether all non-steroidal anti-inflammatory drugs (NSAIDs) exert similar antiproliferative effects on VSMCs, and do so via a common mechanism of action, remains to be shown. In this study, we demonstrate that the NSAIDs aspirin, sodium salicylate, diclofenac, ibuprofen, indometacin and sulindac induce a dose-dependent inhibition of proliferation in rat A10 VSMCs in the absence of significant cytotoxicity. Flow cytometric analyses showed that exposure of A10 cells to diclofenac, indometacin, ibuprofen and sulindac, in the presence of the mitotic inhibitor, nocodazole, led to a significant G0/G1 arrest. In contrast, the salicylates failed to induce a significant G1 arrest since flow cytometry profiles were not significantly different from control cells. Cyclin A levels were elevated, and hyperphosphorylated p107 was present at significant levels, in salicylate-treated A10 cells, consistent with a post-G1/S block, whereas cyclin A levels were low, and hypophosphorylated p107 was the dominant form, in cells treated with other NSAIDs consistent with a G1 arrest. The ubiquitously expressed cyclin-dependent kinase (CDK) inhibitors, p21 and p27, were increased in all NSAID-treated cells. Our results suggest that diclofenac, indometacin, ibuprofen and sulindac inhibit VSMC proliferation by arresting the cell cycle in the G1 phase, whereas the growth inhibitory effect of salicylates probably affects the late S and/or G2/M phases. Irrespective of mechanism, our results suggest that NSAIDs might be of benefit in the treatment of certain vasculoproliferative disorders.
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PMID:Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit vascular smooth muscle cell proliferation via differential effects on the cell cycle. 1280 74

Pyrrolidine dithiocarbamate (PDTC), a metal chelating compound, is known to induce cell death in vascular smooth muscle cells (VSMC). However, the molecular mechanism for PDTC-induced VSMC death is not well understood. Addition of PDTC reduced cell growth and DNA synthesis on VSMC in low density conditions. However, in serum depleted medium, PDTC did not affect the cell viability, suggesting that certain factors in serum may mediate the cytotoxic effect of PDTC. Several metal chelators prevented the cell death induced by PDTC. In a serum-deprived condition, addition of exogenous metals, copper, iron, and zinc, restored the cytotoxic effect of PDTC. These data indicate that metals such as copper, iron, and zinc in serum may mediate the cytotoxic effect of PDTC. At low VSMC density in 10% FBS, treatment of PDTC, which induced a cell-cycle block in G1-phase, induced down-regulation of cyclins and CDKs and up-regulation of the CDK inhibitor p21 expression, whereas up-regulation of p27 or p53 by PDTC was not observed. Finally, we determined PDTC-mediated signaling pathway involved in VSMC death. Among relevant pathways, PDTC induced marked activation of p38MAPK and JNK. Expression of dominant negative p38MAPK and SB203580, a p38MAPK specific inhibitor, blocked PDTC-dependent p38MAPK, growth inhibition, and p21 expression. These data demonstrate that the p38MAPK pathway participates in p21 induction, which consequently leads to decrease of cyclin D1/cdk4 and cyclin E/cdk2 complexes and PDTC-dependent VSMC growth inhibition. In conclusion, an understanding of the molecular mechanisms of PDTC in VSMC provides a theoretical basis for clinical approaches using antioxidant therapies in atherosclerosis.
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PMID:PDTC, metal chelating compound, induces G1 phase cell cycle arrest in vascular smooth muscle cells through inducing p21Cip1 expression: involvement of p38 mitogen activated protein kinase. 1460 33


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