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)

Cell-surface expression of endothelial P-selectin increases adhesion and migration of leukocytes and thus may participate in the pathogenesis of reperfusion injury and atherosclerosis. Angiotensin II (Ang II) is also thought to be involved in such disease states. Nitric oxide (NO) downregulates P-selectin expression, and bradykinin (BK) is known to stimulate NO release from endothelial cells. The objective of this study was to determine the effects of 10-min stimulation of cultured human umbilical endothelial cells (HUVECs) with Ang II, BK, or both on P-selectin expression. Ang II (10(-9)-10(-5) M) stimulated P-selectin expression in a concentration-dependent manner, exhibiting a significant effect at 10(-7) M and reaching a plateau at 5 x 10(-5) M. Pretreatment of HUVECs with the AT1 antagonist losartan and the AT1/AT2 antagonist saralasin but not the AT2 antagonist PD123319 (all at 10(-5) M) markedly attenuated the effect of 10(-7) M Ang II. The effects of Ang II on P-selectin expression were not affected by the presence of the NO synthase inhibitor nitro-L-arginine (L-NA, 5 x 10(-4) M) but were abolished by pretreatment with superoxide dismutase (SOD). BK (10(-6) M) abolished the effects of 10(-7) M Ang II on P-selectin expression but did not affect P-selectin expression induced by desmopressin (0.01-10 microM). L-NA obliterated the blunting effect of BK on the Ang II-induced P-selectin membrane expression. BK alone slightly stimulated P-selectin expression, but in the presence of L-NA, BK markedly enhanced P-selectin expression. The effects of BK in the presence of NA were not altered by SOD, indicating that at difference with Ang II, it acts by a mechanism other than superoxide generation. Thus, Ang II acting on AT1 receptors stimulates superoxide generation, which, in turn, induces expression of P-selectin on the endothelial cell surface. BK inhibits the effects of Ang II, likely acting via NO. We conclude that the balance between Ang II, BK, and NO can regulate P-selectin expression on the endothelial cell membrane, an important component of the cascade leading to leukocyte adhesion to the vascular endothelium.
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PMID:Angiotensin II and bradykinin regulate the expression of P-selectin on the surface of endothelial cells in culture. 975 92

Monocyte infiltration into the vessel wall, a key initial step in the process of atherosclerosis, is mediated in part by monocyte chemoattractant protein-1 (MCP-1). Hypertension, particularly in the presence of an activated renin-angiotensin system, is a major risk factor for the development of atherosclerosis. To investigate a potential molecular basis for a link between hypertension and atherosclerosis, we studied the effects of angiotensin II (Ang II) on MCP-1 gene expression in rat aortic smooth muscle cells. Rat smooth muscle cells treated with Ang II exhibited a dose-dependent increase in MCP-1 mRNA accumulation that was prevented by the AT1 receptor antagonist losartan. Ang II also activated MCP-1 gene transcription. Inhibition of NADH/NADPH oxidase, which generates superoxide and H2O2, with diphenylene iodonium or apocynin decreased Ang II-induced MCP-1 mRNA accumulation. Induction of MCP-1 gene expression by Ang II was inhibited by catalase, suggesting a second messenger role for H2O2. The tyrosine kinase inhibitor genistein and the mitogen-activated protein kinase kinase inhibitor PD098059 inhibited Ang II-induced MCP-1 gene expression, consistent with a mitogen-activated protein kinase-dependent signaling mechanism. Ang II may thus promote atherogenesis by direct activation of MCP-1 gene expression in vascular smooth muscle cells.
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PMID:Angiotensin II induces monocyte chemoattractant protein-1 gene expression in rat vascular smooth muscle cells. 979 45

Angiotensin II (Ang II) promotes vascular smooth muscle cell (VSMC) growth and migration, but the signaling pathways mediating these VSMC behaviors critical to restenosis and atherosclerosis are not completely known. The purpose of the present investigation was to define the role of mitogen-activated protein kinase (MAPK) in Ang II-induced DNA synthesis, migration, and c-fos induction in VSMCs. PD 98059, a synthetic inhibitor of MAPK kinase, or antisense oligodeoxynucleotides (ODNs) to deplete extracellular signal-regulated kinase (ERK)1 and ERK2 MAPKs, were used to inhibit MAPK signaling. PD 98059 at 30 micromol/L reduced Ang II-induced MAPK activity by 69% (P<0.01). Under these conditions, Ang II-induced DNA synthesis was completely inhibited (P<0.01), and Ang II-directed migration was attenuated by 76% (P<0.05). In contrast, induction of c-fos by Ang II was only partially suppressed (58% inhibition, P<0.01). Antisense ODNs against the initiation site of rat ERK1 and ERK2 MAPK mRNAs reduced corresponding protein levels by 63% (P<0.01) and completely inhibited MAPK activation by either Ang II (1 micromol/L) or 10% serum. Antisense ODNs (0.4 micromol/L) completely inhibited Ang II-induced DNA synthesis (P<0.01), decreased migration by 47% (P<0.01), and reduced c-fos induction by 40% (P<0.01 versus control ODN-transfected VSMCs). The Ang II type 1 (AT1)-receptor blocker irbesartan completely blocked DNA synthesis, migration, MAPK activation, and c-fos induction by Ang II in VSMCs. These results demonstrate that activation of MAPK plays a crucial role in Ang II-directed migration and DNA synthesis through the AT1 receptor. In contrast, Ang II-mediated c-fos induction and migration were only partially inhibited by either antisense ODNs or PD 98059, suggesting that other pathways in addition to the MAPK pathway may be involved in these actions of Ang II. We conclude that MAPK is a critical regulatory factor for Ang II-mediated migration and growth in VSMCs. Ang II-induced DNA synthesis showed a stronger MAPK dependence than did Ang II-directed migration or c-fos induction.
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PMID:Central role of the MAPK pathway in ang II-mediated DNA synthesis and migration in rat vascular smooth muscle cells. 988 69

Cross talk between oxidized LDL (ox-LDL) and angiotensin II (Ang II) may be relevant in atherosclerosis. In this study, we examined the presence of a specific endothelial receptor for ox-LDL (LOX-1) and Ang II receptors in human coronary artery endothelial cells (HCAECs). In addition, we studied the effect of Ang II on LOX-1 gene and protein expression. LOX-1 was consistently identified in HCAECs by reverse transcriptase-polymerase chain reaction (RT-PCR), cDNA sequence, Western blot, and 125I-labeled ox-LDL binding assay (Bmax, 29.7 ng/mg protein). The HCAECs also exhibited Ang II receptors (AT1>AT2), as determined by RT-PCR and 125I-labeled Ang II binding assay (Bmax, 2.21 and 1.19 fmol/mg protein, respectively). Incubation of HCAECs with Ang II markedly increased LOX-1 mRNA (RT-PCR) and protein (Western blot) expression. The increase in LOX-1 expression was dependent on Ang II concentration (10(-12) to 10(-6) mol/L). Ang II caused a concentration-dependent increase in 125I-labeled ox-LDL uptake by HCAECs and enhanced ox-LDL-mediated cell injury, as evident from an increase in LDH release and a decrease in cell viability. These effects of Ang II were completely blocked by pretreatment of HCAECs with losartan, a specific AT1 blocker, but not by PD123319, a specific AT2 blocker. These observations indicate the following: (1) HCAECs possess abundant LOX-1 as well as Ang II (AT1>AT2) receptors, (2) Ang II upregulates LOX-1 receptor and ox-LDL uptake, (3) the effects of Ang II are mediated by AT1 activation, and (4) Ang II enhances ox-LDL-mediated injury to HCAECs.
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PMID:Upregulation of endothelial receptor for oxidized low-density lipoprotein (LOX-1) in cultured human coronary artery endothelial cells by angiotensin II type 1 receptor activation. 1032 49

Locally formed angiotensin II (Ang II) and mast cells may participate in the development of atherosclerosis. Chymase, which originates from mast cells, is the major Ang II-forming enzyme in the human heart and aorta in vitro. The aim of the present study was to investigate aortic Ang II-forming activity (AIIFA) and the histochemical localization of each Ang II-forming enzyme in the atheromatous human aorta. Specimens of normal (n=9), atherosclerotic (n=8), and aneurysmal (n=6) human aortas were obtained at autopsy or cardiovascular surgery from 23 subjects (16 men, 7 women). The total, angiotensin-converting enzyme (ACE)-dependent, and chymase-dependent AIIFAs in aortic specimens were determined. The histologic and cellular localization of chymase and ACE were determined by immunocytochemistry. Total AIIFA was significantly higher in atherosclerotic and aneurysmal lesions than in normal aortas. Most of AIIFA in the human aorta in vitro was chymase-dependent in both normal (82%) and atherosclerotic aortas (90%). Immunocytochemical staining of the corresponding aortic sections with antichymase, antitryptase or anti-ACE antibodies showed that chymase-positive mast cells were located in the tunica adventitia of normal and atheromatous aortas, whereas ACE-positive cells were localized in endothelial cells of normal aorta and in macrophages of atheromatous neointima. The density of chymase- and tryptase-positive mast cells in the atherosclerotic lesions was slightly but not significantly higher than that in the normal aortas, and the number of activated mast cells in the aneurysmal lesions (18%) was significantly higher than in atherosclerotic (5%) and normal (1%) aortas. Our results suggest that local Ang II formation is increased in atherosclerotic lesions and that chymase is primarily responsible for this increase. The histologic localization and potential roles of chymase in the development of atherosclerotic lesions appear to be different from those of ACE.
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PMID:Increased chymase-dependent angiotensin II formation in human atherosclerotic aorta. 1037 23

Recent studies suggest that atherosclerosis is a kind of inflammatory process and that cytokine plays important roles in this process. Although it is generally accepted that angiotensin II (Ang II) plays an important role in atherogenesis, the role of Ang II in cytokine production has not been explored. In this report, we investigated the effect of Ang II on the production of interleukin-6 (IL-6), which is a multifunctional proinflammatory cytokine in rat vascular smooth muscle cells. Ang II significantly increased the expression of IL-6 mRNA and protein in a dose-dependent manner (10(-10) to 10(-6) mol/L). The expression of IL-6 mRNA induced by Ang II showed 2 peaks at 30 minutes and 12 to 24 hours after stimulation. The effect of Ang II on IL-6 release and mRNA expression was completely blocked by an Ang II type 1 receptor antagonist, CV11974; however, an Ang II type 2 receptor antagonist, PD123319, showed no effect. Chelating of intracellular Ca(2+) with BAPTA-AM, inhibition of tyrosine kinase with genistein, and inhibition of mitogen-activated protein kinase kinase with PD98059 completely abolished the effect of Ang II. However, downregulation of protein kinase C by pretreatment with a phorbol ester for 24 hours or a specific protein kinase C inhibitor, calphostin C, did not affect the Ang II-induced expression of IL-6 mRNA. Deletion and mutational analysis of IL-6 gene promoter showed that cAMP-responsive element was important for Ang II-induced IL-6 gene expression. Gel mobility shift assay showed an increase of cAMP-responsive element binding protein by Ang II. These results provide new insights into Ang II signaling and the role of Ang II in the progression of inflammatory changes of blood vessels.
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PMID:Induction of interleukin-6 expression by angiotensin II in rat vascular smooth muscle cells. 1040 34

Platelet-derived growth factors (PDGFs) have been implicated in the pathogenesis of vascular proliferative disorders. Vascular smooth muscle cells (VSMCs) are one of the cell types that produce PDGF-B chain in proliferative lesions, although the mechanism of regulation of PDGF-B chain production in these cells is not well understood. In the present study, we demonstrate that angiotensin II (Ang II), which is also implicated in vascular stenosis after angioplasty and atherosclerosis, markedly stimulates PDGF-B chain mRNA expression in cultured newborn rat medial VSMCs and neointimal VSMCs via an AT(1), but not in adult rat VSMCs. In newborn rat VSMCs, Ang II activates extracellular signal-regulated protein kinase (ERK), c-Jun N-terminal protein kinase (JNK), and p38 mitogen-activated protein kinase. The mitogen-activated protein/ERK (MEK) inhibitor PD98059, but not the p38 inhibitor SB203580, abrogates Ang II-induced PDGF-B mRNA expression. Transient transfection analysis using a PDGF-B promoter-luciferase gene reporter construct reveals that Ang II induces transcriptional activation of PDGF-B chain gene, which is abolished by the expression of a dominant negative form of either ERK or JNK, but not of p38. The expression of a dominant negative form of Ras abolishes the stimulatory effects of Ang II on ERK activity and PDGF-B mRNA expression. In adult rat VSMCs, Ang II activates ERK and JNK, but weakly induces Egr-1, a transcription factor implicated in PDGF-B chain gene expression, compared with newborn VSMCs. These data indicate that Ang II activates PDGF-B chain gene expression in VSMCs through mechanisms involving Ras-ERK and JNK.
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PMID:Angiotensin II stimulates platelet-derived growth factor-B chain expression in newborn rat vascular smooth muscle cells and neointimal cells through Ras, extracellular signal-regulated protein kinase, and c-Jun N-terminal protein kinase mechanisms. 1050 81

Angiotensin II (Ang II) was shown to be an important risk factor for accelerated atherosclerosis. Inhibition of Ang II action on the arterial wall by blocking its production with angiotensin converting enzyme (ACE) inhibitors, or by blocking binding to its receptors on cells with antagonists was shown to attenuate atherogenesis in animal model of atherosclerosis. We questioned whether Ang II atherogenicity is related to a stimulatory effect of Ang II on macrophage cholesterol biosynthesis. Angiotensin II injected intraperitoneally once a day (0.1 ml of 10(-7) M per mouse) for a period of 30 days, to the apolipoprotein E deficient mice increased the atherosclerotic lesion area by 95% (P < 0.01 vs. control), compared to placebo-injected mice, with no significant effect on blood pressure or on plasma cholesterol levels. On using mouse peritoneal macrophages (MPMs) that were harvested after intraperitoneally injection of Ang II, an increased rate of cellular cholesterol biosynthesis (measured as incorporation of [3H]acetate into cholesterol) by up to 90% (P < 0.01 vs. control) was observed. In mice treated with the ACE inhibitor, Fosinopril (25 mg/kg per day) a reduction in their MPM's cholesterol synthesis by up to 70% (P < 0.01 vs. control) was obtained. In vitro studies in human monocyte-derived macrophages (HMDM), in MPMs from control BALB/c mice, and in J-774 A.1 macrophage-like cell line demonstrated up to 44, 34 and 30% stimulation of macrophage cholesterol biosynthesis, respectively, following cell incubation with 10(-7) M Ang II for 18 h at 37 degrees C. The stimulatory effect of Ang II on macrophage cholesterol biosynthesis could be related to its interaction with the macrophage AT1 receptor, as Losartan (10(-5) M), an AT1 blocker, but not PD 123319 (10(-5) M), an AT2 blocker, prevented the stimulatory effect on macrophage cholesterol synthesis. Furthermore, in cells that lack the AT1 receptor (RAW macrophages), Ang II did not increase cellular cholesterol synthesis. Ang II increased macrophage 3-hydroxy-3-methyl glutaryl CoA (HMG CoA) reductase mRNA levels in a dose dependent manner in J-774 A.1 macrophages and in MPM. Losartan, the AT1 receptor antagonist clearly attenuated this mRNA induction. We thus conclude that Ang II stimulation of macrophage cholesterol biosynthesis is related to its interaction with the AT1 receptor, followed by stimulation of macrophage HMG CoA reductase gene expression, which leads to increased cellular cholesterol biosynthesis, and can possibly result in macrophage cholesterol accumulation and foam cell formation.
Atherosclerosis 1999 Oct
PMID:Angiotensin II atherogenicity in apolipoprotein E deficient mice is associated with increased cellular cholesterol biosynthesis. 1053 81

Cardiovascular mortality, mainly due to the rupture of unstable atherosclerotic plaques, is reduced by 3-hydroxy-methyl-glutaryl-coenzyme A (HMG-CoA) reductase inhibitors. Inflammatory cells, attracted to the vascular lesion by chemokines, have been implicated in the process of the plaque rupture. In cultured vascular smooth muscle cells (VSMC) and U937 mononuclear cells we have studied the effect of Atorvastatin (Atv) on nuclear factor kappaB (NF-kappaB) activity, an inducer of the mRNA expression of chemokines such as interferon-inducible protein 10 (IP-10) and monocyte chemoattractant protein 1 (MCP-1). Angiotensin II (Ang II) and tumor necrosis factor alpha (TNF-alpha) increased NF-kappaB activity in VSMC (2 and 5-fold, respectively). Preincubation of cells with 10(-7) mol/l Atv diminished this activation (44 and 53%). The inhibition was reversed by mevalonate, farnesylpyrophosphate (FPP) and geranylgeranylpyrophosphate (GGPP), but not by other isoprenoids. Coinciding with the NF-kappaB activation in VSMC, there was a diminution of cytoplasmic IkappaB levels that was recovered by pretreatment with Atv. Ang II and TNF-alpha induced the expression of IP-10 (1.5 and 3.4-fold) and MCP-1 (2.4 and 4-fold) in VSMC. Atv reduced this overexpression around 38 and 35% (IP-10), and 54 and 39% (MCP-1), respectively. Our results strongly suggest that Atv, through the inhibition of NF-kappaB activity and chemokine gene expression, could reduce the inflammation within the atherosclerotic lesion and play a role in the stabilization of the lesion.
Atherosclerosis 1999 Dec
PMID:Atorvastatin reduces NF-kappaB activation and chemokine expression in vascular smooth muscle cells and mononuclear cells. 1055 11

This study was conducted to investigate whether the novel orally active nonpeptide angiotensin II (Ang II) AT(1) receptor antagonist irbesartan interacts with the thromboxane A(2)/prostaglandin endoperoxide H(2) (TxA(2)/PGH(2)) receptor in canine coronary arteries and human platelets. Coronary artery rings were isolated from male dog hearts (n = 18) and isometric tension of vascular rings was measured continuously at optimal basal tension in organ chambers. Autoradiographic binding of [(3)H]SQ29,548, a TxA(2) receptor antagonist, in canine coronary sections was determined. Blood for platelet aggregation studies was collected by venous puncture from healthy human volunteers (n = 6) who were free of aspirin-like agents for at least 2 weeks. Vascular reactivity and platelet aggregation in response to the TxA(2) analogs U46619 and autoradioagraphic receptor binding to the TxA(2) receptor antagonist [(3)H]SQ29,548 were studied with and without irbesartan. The TxA(2) analog U46619 produced dose-dependent vasoconstriction in coronary rings (EC(50) = 11.6 +/- 1.5 nM). Pretreatment with irbesartan inhibited U46619-induced vasoconstriction, and the dose-response curve was shifted to the right in a dose-dependent manner. The EC(50) of U46619 was increased 6- and 35-fold in the presence of 1 and 10 microM of irbesartan without a change of maximal contraction. At 1 microM, irbesartan is 2-fold more potent than the AT(1) receptor antagonist losartan in the inhibition of U46619-induced vasoconstriction in canine coronary arteries. In contrast, neither AT(1) receptor antagonists (CV11974 and valsartan), the AT(2) receptor antagonist PD123319, nor the angiotensin converting enzyme inhibitor lisinopril had any effect on U46619-induced coronary vasoconstriction. Irbesartan did not change potassium chloride-induced vasoconstriction; however, irbesartan did inhibit the vasoconstriction mediated by another TxA(2)/PGH(2) receptor agonist prostaglandin F(2alpha) (PGF(2alpha)). Neither the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester nor the cyclooxygenase inhibitor indomethacin had any effect on irbesartan's attenuation of U46619-induced vasoconstriction. Irbesartan specifically reversed U46619-preconstricted coronary artery rings with and without endothelium in a dose-dependent manner. Irbesartan at high concentrations significantly competed for [(3)H]SQ29,548 binding in canine coronary sections. U46619 stimulated dose-dependent human platelet aggregation of platelet-rich plasma. Preincubation with irbesartan significantly inhibited platelet aggregation in a concentration-dependent manner. In conclusion, the dual antagonistic actions of irbesartan by acting at both the AT(1) and TxA(2) receptors in blood vessels and platelets may overall enhance its therapeutic profile in the treatment of hypertension, atherosclerosis, and arterial thrombosis.
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PMID:Novel angiotensin II AT(1) receptor antagonist irbesartan prevents thromboxane A(2)-induced vasoconstriction in canine coronary arteries and human platelet aggregation. 1060 53


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