Journals

Myocardin Regulates Vascular Smooth Muscle Cell Inflammatory Activation and Disease.

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Myocardin Regulates Vascular Smooth Muscle Cell Inflammatory Activation and Disease.

Arterioscler Thromb Vasc Biol. 2015 Jan 22;

Authors: Ackers-Johnson M, Talasila A, Sage AP, Long X, Bot I, Morrell NW, Bennett MR, Miano JM, Sinha S

Abstract

OBJECTIVE: Atherosclerosis, the cause of 50% of deaths in westernized societies, is widely regarded as a chronic vascular inflammatory disease. Vascular smooth muscle cell (VSMC) inflammatory activation in response to local proinflammatory stimuli contributes to disease progression and is a pervasive feature in developing atherosclerotic plaques. Therefore, it is of considerable therapeutic importance to identify mechanisms that regulate the VSMC inflammatory response.

APPROACH AND RESULTS: We report that myocardin, a powerful myogenic transcriptional coactivator, negatively regulates VSMC inflammatory activation and vascular disease. Myocardin levels are reduced during atherosclerosis, in association with phenotypic switching of smooth muscle cells. Myocardin deficiency accelerates atherogenesis in hypercholesterolemic apolipoprotein E(-/-) mice. Conversely, increased myocardin expression potently abrogates the induction of an array of inflammatory cytokines, chemokines, and adhesion molecules in VSMCs. Expression of myocardin in VSMCs reduces lipid uptake, macrophage interaction, chemotaxis, and macrophage-endothelial tethering in vitro, and attenuates monocyte accumulation within developing lesions in vivo. These results demonstrate that endogenous levels of myocardin are a critical regulator of vessel inflammation.

CONCLUSIONS: We propose myocardin as a guardian of the contractile, noninflammatory VSMC phenotype, with loss of myocardin representing a critical permissive step in the process of phenotypic transition and inflammatory activation, at the onset of vascular disease.

PMID: 25614278 [PubMed - as supplied by publisher]

Pivotal Role of Serum- and Glucocorticoid-Inducible Kinase 1 in Vascular Inflammation and Atherogenesis.

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Pivotal Role of Serum- and Glucocorticoid-Inducible Kinase 1 in Vascular Inflammation and Atherogenesis.

Arterioscler Thromb Vasc Biol. 2015 Jan 22;

Authors: Borst O, Schaub M, Walker B, Schmid E, Muenzer P, Voelkl J, Alesutan I, Rodríguez JM, Vogel S, Schoenberger T, Metzger K, Rath D, Umbach A, Kuhl D, Müller II, Seizer P, Geisler T, Gawaz M, Lang F

Abstract

OBJECTIVE: Atherosclerosis, an inflammatory disease of arterial vessel walls, requires migration and matrix metalloproteinase (MMP)-9-dependent invasion of monocytes/macrophages into the vascular wall. MMP-9 expression is stimulated by transcription factor nuclear factor-κB, which is regulated by inhibitor κB and thus inhibitor κB-kinase IκB kinase. Regulators of nuclear factor-κB include serum- and glucocorticoid-inducible kinase 1 (SGK1). The present study explored involvement of SGK1 in vascular inflammation and atherogenesis.

APPROACH AND RESULTS: Gene-targeted apolipoprotein E (ApoE)-deficient mice without (apoe(-/-)sgk1(+/+)) or with (apoe(-/-)sgk1(-/-)) additional SGK1 knockout received 16-week cholesterol-rich diet. According to immunohistochemistry atherosclerotic lesions in aorta and carotid artery, vascular CD45(+) leukocyte infiltration, Mac-3(+) macrophage infiltration, vascular smooth muscle cell content, MMP-2, and MMP-9 positive areas in atherosclerotic tissue were significantly less in apoe(-/-)sgk1(-/-)mice than in apoe(-/-)sgk1(+/+)mice. As determined by Boyden chamber, thioglycollate-induced peritonitis and air pouch model, migration of SGK1-deficient CD11b(+)F4/80(+) macrophages was significantly diminished in vitro and in vivo. Zymographic MMP-2 and MMP-9 production, MMP-9 activity and invasion through matrigel in vitro were significantly less in sgk1(-/-) than in sgk1(+/+)macrophages and in control plasmid-transfected or inactive (K127N)SGK1-transfected than in constitutively active (S422D)SGK1-transfected THP-1 cells. Confocal microscopy revealed reduced macrophage number and macrophage MMP-9 content in plaques of apoe(-/-)sgk1(-/-) mice. In THP-1 cells, MMP-inhibitor GM6001 (25 μmol/L) abrogated (S422D)SGK1-induced MMP-9 production and invasion. According to reverse transcription polymerase chain reaction, MMP-9 transcript levels were significantly reduced in sgk1(-/-)macrophages and strongly upregulated in (S422D)SGK1-transfected THP-1 cells compared with control plasmid-transfected or (K127N)SGK1-transfected THP-1 cells. According to immunoblotting and confocal microscopy, phosphorylation of IκB kinase and inhibitor κB and nuclear translocation of p50 were significantly lower in sgk1(-/-)macrophages than in sgk1(+/+)macrophages and significantly higher in (S422D)SGK1-transfected THP-1 cells than in control plasmid-transfected or (K127N)SGK1-transfected THP-1 cells. Treatment of (S422D)SGK1-transfected THP-1 cells with IκB kinase-inhibitor BMS-345541 (10 μmol/L) abolished (S422D)SGK1-induced increase of MMP-9 transcription and gelatinase activity.

CONCLUSIONS: SGK1 plays a pivotal role in vascular inflammation during atherogenesis. SGK1 participates in the regulation of monocyte/macrophage migration and MMP-9 transcription via regulation of nuclear factor-κB.

PMID: 25614279 [PubMed - as supplied by publisher]

Mipomersen, an Antisense Oligonucleotide to Apolipoprotein B-100, Reduces Lipoprotein(a) in Various Populations With Hypercholesterolemia: Results of 4 Phase III Trials.

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Mipomersen, an Antisense Oligonucleotide to Apolipoprotein B-100, Reduces Lipoprotein(a) in Various Populations With Hypercholesterolemia: Results of 4 Phase III Trials.

Arterioscler Thromb Vasc Biol. 2015 Jan 22;

Authors: Santos RD, Raal FJ, Catapano AL, Witztum JL, Steinhagen-Thiessen E, Tsimikas S

Abstract

OBJECTIVE: Lp(a) is an independent, causal, genetic risk factor for cardiovascular disease and aortic stenosis. Current pharmacological lipid-lowering therapies do not optimally lower Lp(a), particularly in patients with familial hypercholesterolemia (FH).

APPROACH AND RESULTS: In 4 phase III trials, 382 patients on maximally tolerated lipid-lowering therapy were randomized 2:1 to weekly subcutaneous mipomersen 200 mg (n=256) or placebo (n=126) for 26 weeks. Populations included homozygous FH, heterozygous FH with concomitant coronary artery disease (CAD), severe hypercholesterolemia, and hypercholesterolemia at high risk for CAD. Lp(a) was measured 8× between baseline and week 28 inclusive. Of the 382 patients, 57% and 44% had baseline Lp(a) levels >30 and >50 mg/dL, respectively. In the pooled analysis, the mean percent decrease (median, interquartile range in Lp(a) at 28 weeks was significantly greater in the mipomersen group compared with placebo (-26.4 [-42.8, -5.4] versus -0.0 [-10.7, 15.3]; P<0.001). In the mipomersen group in patients with Lp(a) levels >30 or >50 mg/dL, attainment of Lp(a) values ≤30 or ≤50 mg/dL was most frequent in homozygous FH and severe hypercholesterolemia patients. In the combined groups, modest correlations were present between percent change in apolipoprotein B-100 and Lp(a) (r=0.43; P<0.001) and low-density lipoprotein cholesterol and Lp(a) (r=0.36; P<0.001) plasma levels.

CONCLUSIONS: Mipomersen consistently and effectively reduced Lp(a) levels in patients with a variety of lipid abnormalities and cardiovascular risk. Modest correlations were present between apolipoprotein B-100 and Lp(a) lowering but the mechanistic relevance mediating Lp(a) reduction is currently unknown.

PMID: 25614280 [PubMed - as supplied by publisher]

Gestational Diabetes Mellitus Impairs Fetal Endothelial Cell Functions Through a Mechanism Involving MicroRNA-101 and Histone Methyltransferase Enhancer of Zester Homolog-2.

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Gestational Diabetes Mellitus Impairs Fetal Endothelial Cell Functions Through a Mechanism Involving MicroRNA-101 and Histone Methyltransferase Enhancer of Zester Homolog-2.

Arterioscler Thromb Vasc Biol. 2015 Jan 22;

Authors: Floris I, Descamps B, Vardeu A, Mitić T, Posadino AM, Shantikumar S, Sala-Newby G, Capobianco G, Mangialardi G, Howard L, Dessole S, Urrutia R, Pintus G, Emanueli C

Abstract

OBJECTIVE: Gestational diabetes mellitus (GDM) produces fetal hyperglycemia with increased lifelong risks for the exposed offspring of cardiovascular and other diseases. Epigenetic mechanisms induce long-term gene expression changes in response to in utero environmental perturbations. Moreover, microRNAs (miRs) control the function of endothelial cells (ECs) under physiological and pathological conditions and can target the epigenetic machinery. We investigated the functional and expressional effect of GDM on human fetal ECs of the umbilical cord vein (HUVECs). We focused on miR-101 and 1 of its targets, enhancer of zester homolog-2 (EZH2), which trimethylates the lysine 27 of histone 3, thus repressing gene transcription. EZH2 exists as isoforms α and β APPROACH AND RESULTS: HUVECs were prepared from GDM or healthy pregnancies and tested in apoptosis, migration, and Matrigel assays. GDM-HUVECs demonstrated decreased functional capacities, increased miR-101 expression, and reduced EZH2- β and trimethylation of histone H3 on lysine 27 levels. MiR-101 inhibition increased EZH2 expression and improved GDM-HUVEC function. Healthy HUVECs were exposed to high or normal d-glucose concentration for 48 hours and then tested for miR-101 and EZH2 expression. Similar to GDM, high glucose increased miR-101 expression. Chromatin immunoprecipitation using an antibody for EZH2 followed by polymerase chain reaction analyses for miR-101 gene promoter regions showed that both GDM and high glucose concentration reduced EZH2 binding to the miR-101 locus in HUVECs. Moreover, EZH2-β overexpression inhibited miR-101 promoter activity in HUVECs.

CONCLUSIONS: GDM impairs HUVEC function via miR-101 upregulation. EZH2 is both a transcriptional inhibitor and a target gene of miR-101 in HUVECs, and it contributes to some of the miR-101-induced defects of GDM-HUVECs.

PMID: 25614281 [PubMed - as supplied by publisher]

Role of Oral Anticoagulants in Patients After Acute Coronary Syndrome.

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Role of Oral Anticoagulants in Patients After Acute Coronary Syndrome.

Arterioscler Thromb Vasc Biol. 2015 Jan 22;

Authors: Carreras E, Mega JL

Abstract

After an acute coronary syndrome, patients continue to be at risk of adverse cardiovascular events despite treatment with the current standard of antithrombotic therapy. The risk may be in part secondary to thrombin, which remains elevated after an acute coronary syndrome event. Several studies have investigated the utility of adding oral anticoagulation to post-acute coronary syndrome medical regimens, with the most promising results coming from the addition of low-dose nonvitamin K oral anticoagulants. Focusing on optimal dosing strategies and applying therapies to the appropriate populations provide the ability to maximize benefit and minimize risk.

PMID: 25614282 [PubMed - as supplied by publisher]

Galectin-3 Predicts Long-Term Cardiovascular Death in High-Risk Patients With Coronary Artery Disease.

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Galectin-3 Predicts Long-Term Cardiovascular Death in High-Risk Patients With Coronary Artery Disease.

Arterioscler Thromb Vasc Biol. 2015 Jan 22;

Authors: Maiolino G, Rossitto G, Pedon L, Cesari M, Frigo AC, Azzolini M, Plebani M, Rossi GP

Abstract

OBJECTIVE: Galectin-3 (Gal-3) can affect atherogenesis by multiple mechanisms, but it remains scarcely known whether plasma Gal-3 levels predict cardiovascular events in patients with coronary artery disease. Therefore, we investigated whether Gal-3 predicts cardiovascular death in patients with coronary artery disease of the Genetic and ENvironmental factors In Coronary Artery disease study.

APPROACH AND RESULTS: In a prospective cohort study, we measured the plasma levels of Gal-3 in 1013 randomly selected patients who underwent coronary angiography and long-term follow-up to assess incident cardiovascular events. The primary end points were (1) cardiovascular death and (2) a composite of cardiovascular death, acute coronary syndrome, and stroke. Secondary end points entailed (1) acute myocardial infarction, (2) stroke, and (3) a composite fatal ischemic event including fatal myocardial infarction and stroke. The effect of Gal-3 on prognosis was assessed using Kaplan-Meier analysis and multivariate Cox’s regression. During long-term follow-up (median, 7.2 years), 115 cardiovascular deaths occurred (15.2%), more commonly in the high Gal-3 tertile (25.2%) than in the intermediate and the low tertiles (13.6% versus 7.5%, respectively; P<0.001). The adverse prognostic effect of high Gal-3 was confirmed in subgroup analysis of the patients with angiographically documented coronary artery disease and also of those with a normal left ventricular ejection fraction. At multivariate analysis, Gal-3 was a predictor of cardiovascular mortality (hazard ratio, 1.79; 95% confidence interval, 1.10-2.93; P=0.020) along with age, left ventricular ejection fraction, and coronary atherosclerotic burden.

CONCLUSIONS: In high cardiovascular risk patients referred for coronary angiography Gal-3 is a strong independent predictor of cardiovascular death.

PMID: 25614283 [PubMed - as supplied by publisher]

Fibrin, γ’-Fibrinogen, and Transclot Pressure Gradient Control Hemostatic Clot Growth During Human Blood Flow Over a Collagen/Tissue Factor Wound.

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Fibrin, γ’-Fibrinogen, and Transclot Pressure Gradient Control Hemostatic Clot Growth During Human Blood Flow Over a Collagen/Tissue Factor Wound.

Arterioscler Thromb Vasc Biol. 2015 Jan 22;

Authors: Muthard RW, Welsh JD, Brass LF, Diamond SL

Abstract

OBJECTIVE: Biological and physical factors interact to modulate blood response in a wounded vessel, resulting in a hemostatic clot or an occlusive thrombus. Flow and pressure differential (ΔP) across the wound from the lumen to the extravascular compartment may impact hemostasis and the observed core/shell architecture. We examined physical and biological factors responsible for regulating thrombin-mediated clot growth.

APPROACH AND RESULTS: Using factor XIIa-inhibited human whole blood perfused in a microfluidic device over collagen/tissue factor at controlled wall shear rate and ΔP, we found thrombin to be highly localized in the P-selectin(+) core of hemostatic clots. Increasing ΔP from 9 to 29 mm Hg (wall shear rate=400 s(-1)) reduced P-selectin(+) core size and total clot size because of enhanced extravasation of thrombin. Blockade of fibrin polymerization with 5 mmol/L Gly-Pro-Arg-Pro dysregulated hemostasis by enhancing both P-selectin(+) core size and clot size at 400 s(-1) (20 mm Hg). For whole-blood flow (no Gly-Pro-Arg-Pro), the thickness of the P-selectin-negative shell was reduced under arterial conditions (2000 s(-1), 20 mm Hg). Consistent with the antithrombin-1 activity of fibrin implicated with Gly-Pro-Arg-Pro, anti-γ’-fibrinogen antibody enhanced core-localized thrombin, core size, and overall clot size, especially at venous (100 s(-1)) but not arterial wall shear rates (2000 s(-1)). Pathological shear (15 000 s(-1)) and Gly-Pro-Arg-Pro synergized to exacerbate clot growth.

CONCLUSIONS: Hemostatic clotting was dependent on core-localized thrombin that (1) triggered platelet P-selectin display and (2) was highly regulated by fibrin and the transclot ΔP. Also, γ’-fibrinogen had a role in venous but not arterial conditions.

PMID: 25614284 [PubMed - as supplied by publisher]

Wnt16 Attenuates TGFβ-Induced Chondrogenic Transformation in Vascular Smooth Muscle.

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Wnt16 Attenuates TGFβ-Induced Chondrogenic Transformation in Vascular Smooth Muscle.

Arterioscler Thromb Vasc Biol. 2015 Jan 22;

Authors: Beazley KE, Nurminsky D, Lima F, Gandhi C, Nurminskaya MV

Abstract

OBJECTIVE: Phenotypic plasticity of vascular smooth muscle cells (VSMCs) contributes to cardiovascular disease. Chondrocyte-like transformation of VSMCs associates with vascular calcification and underlies the formation of aortic cartilaginous metaplasia induced in mice by genetic loss of matrix Gla protein (MGP). Previous microarray analysis identified a dramatic downregulation of Wnt16 in calcified MGP-null aortae, suggesting an antagonistic role for Wnt16 in the chondrogenic transformation of VSMCs.

APPROACH AND RESULTS: Wnt16 is significantly downregulated in MGP-null aortae, before the histological appearance of cartilaginous metaplasia, and in primary MGP-null VSMCs. In contrast, intrinsic TGFβ is activated in MGP-null VSMCs and is necessary for spontaneous chondrogenesis of these cells in high-density micromass cultures. TGFβ3-induced chondrogenic transformation in wild-type VSMCs associates with Smad2/3-dependent Wnt16 downregulation, but Wnt16 does not suppress TGFβ3-induced Smad activation. In addition, TGFβ3 inhibits Notch signaling in wild-type VSMCs, and this pathway is downregulated in MGP-null aortae. Exogenous Wnt16 stimulates Notch activity and attenuates TGFβ3-induced downregulation of Notch in wild-type VSMCs, prevents chondrogenesis in MGP-null and TGFβ3-treated wild-type VSMCs, and stabilizes expression of contractile markers of differentiated VSMCs.

CONCLUSIONS: We describe a novel TGFβ-Wnt16-Notch signaling conduit in the chondrocyte-like transformation of VSMCs and identify endogenous TGFβ activity in MGP-null VSMCs as a critical mediator of chondrogenesis. Our proposed model suggests that the activated TGFβ pathway inhibits expression of Wnt16, which is a positive regulator of Notch signaling and a stabilizer of VSMC phenotype. These data advance the comprehensive mechanistic understanding of VSMC transformation and may identify a novel potential therapeutic target in vascular calcification.

PMID: 25614285 [PubMed - as supplied by publisher]

Dimorphic Effects of Transforming Growth Factor-β Signaling During Aortic Aneurysm Progression in Mice Suggest a Combinatorial Therapy for Marfan Syndrome.

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Dimorphic Effects of Transforming Growth Factor-β Signaling During Aortic Aneurysm Progression in Mice Suggest a Combinatorial Therapy for Marfan Syndrome.

Arterioscler Thromb Vasc Biol. 2015 Jan 22;

Authors: Cook JR, Clayton NP, Carta L, Galatioto J, Chiu E, Smaldone S, Nelson CA, Cheng SH, Wentworth BM, Ramirez F

Abstract

OBJECTIVE: Studies of mice with mild Marfan syndrome (MFS) have correlated the development of thoracic aortic aneurysm (TAA) with improper stimulation of noncanonical (Erk-mediated) TGFβ signaling by the angiotensin type I receptor (AT1r). This correlation was largely based on comparable TAA modifications by either systemic TGFβ neutralization or AT1r antagonism. However, subsequent investigations have called into question some key aspects of this mechanism of arterial disease in MFS. To resolve these controversial points, here we made a head-to-head comparison of the therapeutic benefits of TGFβ neutralization and AT1r antagonism in mice with progressively severe MFS (Fbn1(mgR/mgR) mice).

APPROACH AND RESULTS: Aneurysm growth, media degeneration, aortic levels of phosphorylated Erk and Smad proteins and the average survival of Fbn1(mgR/mgR) mice were compared after a ≈3-month-long treatment with placebo and either the AT1r antagonist losartan or the TGFβ-neutralizing antibody 1D11. In contrast to the beneficial effect of losartan, TGFβ neutralization either exacerbated or mitigated TAA formation depending on whether treatment was initiated before (postnatal day 16; P16) or after (P45) aneurysm formation, respectively. Biochemical evidence-related aneurysm growth with Erk-mediated AT1r signaling, and medial degeneration with TGFβ hyperactivity that was in part AT1r dependent. Importantly, P16-initiated treatment with losartan combined with P45-initiated administration of 1D11 prevented death of Fbn1(mgR/mgR) mice from ruptured TAA.

CONCLUSIONS: By demonstrating that promiscuous AT1r and TGFβ drive partially overlapping processes of arterial disease in MFS mice, our study argues for a therapeutic strategy against TAA that targets both signaling pathways although sparing the early protective role of TGFβ.

PMID: 25614286 [PubMed - as supplied by publisher]

Impaired Integrin β3 Delays Endothelial Cell Regeneration and Contributes to Arteriovenous Graft Failure in Mice.

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Impaired Integrin β3 Delays Endothelial Cell Regeneration and Contributes to Arteriovenous Graft Failure in Mice.

Arterioscler Thromb Vasc Biol. 2015 Jan 22;

Authors: Liang M, Wang Y, Liang A, Dong JF, Du J, Cheng J

Abstract

OBJECTIVE: Neointima formation is associated with stenosis and subsequent thrombosis in arteriovenous grafts (AVGs). A role of integrin β3 in the neointima formation of AVGs remains poorly understood.

APPROACH AND RESULTS: In integrin β3(-/-) mice, we found significantly accelerated occlusion of AVGs compared with the wild-type mice. This is caused by the development of neointima and lack of endothelial regeneration. The latter is a direct consequence of impaired functions of circulating angiogenic cells (CACs) and platelets in integrin β3(-/-) mice. Evidence suggests the involvement of platelet regulating CAC homing to and differentiation at graft sites via transforming growth factor-β1 and Notch signaling pathway. First, CACs deficient of integrin β3 impaired adhesion activity toward exposed subendothelium. Second, platelets from integrin β3(-/-) mice failed to sufficiently stimulate CACs to differentiate into mature endothelial cells. Finally, we found that transforming growth factor-β1 level was increased in platelets from integrin β3(-/-) mice and resulted in enhanced Notch1 activation in CACs in AVGs. These results demonstrate that integrin β3 is critical for endothelial cell homing and differentiation. The increased transforming growth factor-β1 and Notch1 signaling mediates integrin β3(-/-)-induced AVG occlusion. This accelerated occlusion of AVGs was reversed in integrin β3(-/-) mice transplanted with the bone marrow from wild-type mice.

CONCLUSIONS: Our results suggest that boosting integrin β3 function in the endothelial cells and platelets could prevent neointima and thrombosis in AVGs.

PMID: 25614287 [PubMed - as supplied by publisher]