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ABSTRACT: PGI2 signaling through IP inhibits allergen-induced inflammatory responses in mice. We reported previously that PGI2 analogs decreased proinflammatory cytokine and chemokine production by mature BMDCs. However, whether PGI2 modulates the function of immature DCs has not been investigated. We hypothesized that PGI2 negatively regulates immature DC function and investigated the effect of PGI2 analogs on immature BMDC antigen uptake and migration in vitro and in vivo. Immature BMDCs were obtained from WT and IPKO mice, both on a C57BL/6 background. The PGI2 analog cicaprost decreased FITC-OVA uptake by immature BMDCs. In addition, cicaprost increased immature BMDC podosome dissolution, pro-MMP-9 production, cell surface CCR7 expression, and chemotactic migration toward CCL19 and CCL21, as well as chemokinesis, in an IP-specific fashion. These in vitro results suggested that cicaprost promotes migration of immature DCs from mucosal surface to draining LNs. This concept was supported by the finding that migration of immature GFP(+) BMDCs to draining LNs was enhanced by pretreatment with cicaprost. Further, migration of immature lung DCs labeled with PKH26 was enhanced by intranasal cicaprost administration. Our results suggest PGI2-IP signaling increases immature DC migration to the draining LNs and may represent a novel mechanism by which this eicosanoid inhibits immune responses.
Journal of leukocyte biology 04/2013; · 4.99 Impact Factor
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Circulation Research 02/2013; 112(4):576-8. · 9.49 Impact Factor
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Santhi K Ganesh,
Vinicius Tragante,
Wei Guo,
Yiran Guo,
Matthew B Lanktree,
Erin N Smith,
Toby Johnson,
Berta Almoguera Castillo,
John Barnard,
Jens Baumert, [......],
Pim van der Harst,
Yvonne T van der Schouw,
Nilesh J Samani,
Andrew D Johnson,
Patricia B Munroe,
Paul I W de Bakker,
Xiaofeng Zhu,
Daniel Levy,
Brendan J Keating,
Folkert W Asselbergs
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ABSTRACT: Blood pressure (BP) is a heritable determinant of risk for cardiovascular disease. To investigate genetic associations with systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), and pulse pressure (PP), we genotyped ∼50,000 single nucleotide polymorphisms (SNPs) that capture variation in ∼2,100 candidate genes for cardiovascular phenotypes in 61,619 individuals of European ancestry from cohort studies in the US and Europe. We identified novel associations between rs347591 and SBP (chromosome 3p25.3, in an intron of HRH1) and between rs2169137 and DBP (chromosome1q32.1 in an intron of MDM4) and between rs2014408 and SBP (chromosome 11p15 in an intron of SOX6), previously reported to be associated with MAP. We also confirmed ten previously known loci associated with SBP, DBP, MAP, or PP (ADRB1, ATP2B1, SH2B3/ATXN2, CSK, CYP17A1, FURIN, HFE, LSP1, MTHFR, SOX6) at array-wide significance (P value<2.4 x 10(-6)). We then replicated these associations in an independent set of 65,886 individuals of European ancestry. Findings from eQTL analysis showed associations of SNPs in the MDM4 region with MDM4 expression. We did not find evidence of association of the two novel SNPs in MDM4 and HRH1 with sequelae of high BP including coronary artery disease, left ventricular hypertrophy, or stroke. In summary, we identified two novel loci associated with BP and confirmed multiple previously reported associations. Our findings extend our understanding of genes involved in BP regulation, some of which may eventually provide new targets for therapeutic intervention.
Human Molecular Genetics 01/2013; · 7.64 Impact Factor
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Proceedings of the National Academy of Sciences 01/2013; · 9.68 Impact Factor
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Zhou Yu,
Emanuela Ricciotti,
Takashi Miwa,
Shulin Liu,
Kaori Ihida-Stansbury,
Gavin Landersberg,
Peter Lloyd Jones,
Rosario Scalia,
Wenchao Song,
Richard K Assoian, Garret A Fitzgerald
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ABSTRACT: Rationale: Human genetics have implicated the 5- lipoxygenase (5-LO) enzyme in the pathogenesis of cardiovascular disease and an inhibitor of the 5-LO activating protein (FLAP) is in clinical development for asthma. Objective: Here we determined whether FLAP deletion modifies the response to vascular injury. Methods and Results: Vascular remodeling was characterized 4 weeks after femoral arterial injury in FLAP knockout (FLAP KO) mice and wild type (WT) controls. Both neointimal hyperplasia and the intima / media ratio of the injured artery were significantly reduced in the FLAP KOs while endothelial integrity was preserved. Lesional myeloid cells were depleted and vascular smooth muscle cell (VSMC) proliferation, as reflected by bromodeoxyuridine (BrdU) incorporation, was markedly attenuated by FLAP deletion. Inflammatory cytokine release from FLAP KO macrophages was depressed and their restricted ability to induce VSMC migration ex vivo was rescued with leukotriene B4 (LTB4). FLAP deletion restrained injury and attenuated upregulation of the extracellular matrix protein, tenascin C (TNC), which affords a scaffold for VSMC migration. Correspondingly, the phenotypic modulation of VSMC to a more synthetic phenotype, reflected by morphological change, loss of α-smooth muscle cell actin and upregulation of vascular cell adhesion molecule (VCAM) -1 was also suppressed in FLAP KO mice. Transplantation of FLAP replete myeloid cells rescued the proliferative response to vascular injury. Conclusions: Expression of lesional FLAP in myeloid cells promotes LTB4 dependent VSMC phenotypic modulation, intimal migration and proliferation.
Circulation Research 12/2012; · 9.49 Impact Factor
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ABSTRACT: BACKGROUND: Low dose aspirin reduces the secondary incidence of myocardial infarction and stroke. Drug resistance to aspirin might result in treatment failure. Despite this concern, no clear definition of "aspirin resistance" has emerged and estimates of its incidence have varied remarkably. We aimed to determine the commonality of a mechanistically consistent, stable and specific phenotype of true pharmacological resistance to aspirin - such as might be explained by genetic causes. METHODS AND RESULTS: Healthy volunteers (n=400) were screened for their response to a single oral dose of 325 mg immediate release or enteric coated aspirin. Response parameters reflected the activity of aspirin's molecular target, cyclooxygenase-1. Individuals who appeared "aspirin resistant" on one occasion underwent repeat testing and if still "resistant" were exposed to low dose enteric coated aspirin (81 mg) and clopidogrel (75 mg) for one week each. Variable absorption caused a high frequency of apparent resistance to a single dose of 325 mg enteric coated aspirin (up to 49%) but not to immediate release aspirin (0%). All individuals responded to aspirin upon repeated exposure, extension of the post dosing interval or addition of aspirin to their platelets ex vivo. CONCLUSIONS: Pharmacological resistance to aspirin is rare; this study failed to identify a single case of true drug resistance. Pseudoresistance, reflecting delayed and reduced drug absorption, complicates enteric coated but not immediate release aspirin administration. CLINICAL TRIAL REGISTRATION INFORMATION: clinicaltrials.gov. Identifier: NCT00948987.
Circulation 12/2012; · 14.74 Impact Factor
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ABSTRACT: BACKGROUND: Global deletion of microsomal prostaglandin E synthase (mPGES) -1 in mice attenuates the response to vascular injury without a predisposition to thrombogenesis or hypertension. However, enzyme deletion results in cell specific differential utilization by prostaglandin (PG) synthases of the accumulated PGH(2) substrate. Here, we generated mice deficient in mPGES-1 in vascular smooth muscle cells (VSMCs), endothelial cells (ECs) and myeloid cells further to elucidate the cardiovascular function of this enzyme. METHODS AND RESULTS: VSMC and EC mPGES-1 deletion did not alter blood pressure at baseline or in response to a high salt diet. The propensity to evoked macrovascular and microvascular thrombogenesis was also unaltered. However, both VSMC and EC mPGES-1 deficient mice exhibited a markedly exaggerated neointimal hyperplastic response to wire injury of the femoral artery compared to their littermate controls. The hyperplasia was associated with increased proliferating cell nuclear antigen (PCNA) and tenascin-C (TN-C) expression. In contrast, the response to injury was markedly suppressed by myeloid cell depletion of mPGES-1 with decreased hyperplasia, leukocyte infiltration and expression of PCNA and TN-C. Conditioned medium derived from mPGES-1 deficient macrophages less potently induced VSMC proliferation and migration than that from wild type macrophages. CONCLUSION: Deletion of mPGES-1 in the vasculature and myeloid cells differentially modulates the response to vascular injury, implicating macrophage mPGES-1 as a cardiovascular drug target.
Circulation 11/2012; · 14.74 Impact Factor
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Georgios K Paschos,
Salam Ibrahim,
Wen-Liang Song,
Takeshige Kunieda,
Gregory Grant,
Teresa M Reyes,
Christopher A Bradfield,
Cheryl H Vaughan,
Michael Eiden,
Mojgan Masoodi,
Julian L Griffin,
Fenfen Wang,
John A Lawson, Garret A Fitzgerald
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ABSTRACT: Adipocytes store excess energy in the form of triglycerides and signal the levels of stored energy to the brain. Here we show that adipocyte-specific deletion of Arntl (also known as Bmal1), a gene encoding a core molecular clock component, results in obesity in mice with a shift in the diurnal rhythm of food intake, a result that is not seen when the gene is disrupted in hepatocytes or pancreatic islets. Changes in the expression of hypothalamic neuropeptides that regulate appetite are consistent with feedback from the adipocyte to the central nervous system to time feeding behavior. Ablation of the adipocyte clock is associated with a reduced number of polyunsaturated fatty acids in adipocyte triglycerides. This difference between mutant and wild-type mice is reflected in the circulating concentrations of polyunsaturated fatty acids and nonesterified polyunsaturated fatty acids in hypothalamic neurons that regulate food intake. Thus, this study reveals a role for the adipocyte clock in the temporal organization of energy regulation, highlights timing as a modulator of the adipocyte-hypothalamic axis and shows the impact of timing of food intake on body weight.
Nature medicine 11/2012; · 27.14 Impact Factor
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Andrew N Lowell,
Hui Qiao,
Ting Liu,
Takashi Ishikawa,
Hualei Zhang,
Sean Oriana,
Miao Wang,
Emanuela Ricciotti, Garret A Fitzgerald,
Rong Zhou,
Yoko Yamakoshi
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ABSTRACT: To allow visualization of macrophage-rich and miniature-sized atheromas by magnetic resonance (MR) imaging, we have converted low-density lipoprotein (LDL) into MR-active nanoparticles via the intercalation of a 1,4,7,10-tetraazacyclodecane-1,4,7-triacetic acid (DO3A) derivative and the subsequent coordination reaction with Gd3+. After careful removal of non-chelated Gd3+, an MR-active LDL (Gd3+-LDL) with a remarkably high payload of Gd3+ (in excess of 200 Gd3+ atoms per particle) and a high relaxivity (R1 = 20.1 s-1mM-1 per Gd3+ or 4040 s-1mM-1 per LDL) was obtained. Dynamic light-scattering photon correlation spectroscopy (DLS) and cryo transmission electron microscope (cryoTEM) images showed that Gd3+-LDL particles did not aggregate and remained a similar size (25-30 nm) to native LDL. Intravenous injection of Gd3+-LDL into an atherosclerotic mouse model (ApoE-/-) resulted in an extremely high enhancement of the atheroma-bearing aortic walls at 48 h after injection. Free Gd3+ dissociation from Gd3+-LDL was not detected over the imaging time window (96 h). Because autologous LDL can be isolated, modified, and returned to the same patient, our results suggest that MR-active LDL can potentially be used as a non-infectious and non-immunogenic imaging probe for the enhancement of atheroplaques presumably via the uptake into macrophages inside the plaque.
Bioconjugate Chemistry 10/2012; · 4.93 Impact Factor
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Ying Yu,
Emanuela Ricciotti,
Rosario Scalia,
Soon Yew Tang,
Gregory Grant,
Zhou Yu,
Gavin Landesberg,
Irene Crichton,
Weichen Wu,
Ellen Puré,
Colin D Funk, Garret A FitzGerald
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ABSTRACT: Prostacyclin (PGI(2)) is a vasodilator and platelet inhibitor, properties consistent with cardioprotection. More than a decade ago, inhibition of cyclooxygenase-2 (COX-2) by the nonsteroidal anti-inflammatory drugs (NSAIDs) rofecoxib and celecoxib was found to reduce the amount of the major metabolite of PGI(2) (PGI-M) in the urine of healthy volunteers. This suggested that NSAIDs might cause adverse cardiovascular events by reducing production of cardioprotective PGI(2). This prediction was based on the assumption that the concentration of PGI-M in urine likely reflected vascular production of PGI(2) and that other cardioprotective mediators, especially nitric oxide (NO), were not able to compensate for the loss of PGI(2). Subsequently, eight placebo-controlled clinical trials showed that NSAIDs that block COX-2 increase adverse cardiovascular events. We connect tissue-specific effects of NSAID action and functional correlates in mice with clinical outcomes in humans by showing that deletion of COX-2 in the mouse vasculature reduces excretion of PGI-M in urine and predisposes the animals to both hypertension and thrombosis. Furthermore, vascular disruption of COX-2 depressed expression of endothelial NO synthase and the consequent release and function of NO. Thus, suppression of PGI(2) formation resulting from deletion of vascular COX-2 is sufficient to explain the cardiovascular hazard from NSAIDs, which is likely to be augmented by secondary mechanisms such as suppression of NO production.
Science translational medicine 05/2012; 4(132):132ra54. · 7.80 Impact Factor
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ABSTRACT: Suppression of cyclooxygenase 2 (COX-2)-derived prostacyclin (PGI(2)) is sufficient to explain most elements of the cardiovascular hazard from nonsteroidal antinflammatory drugs (NSAIDs). However, randomized trials are consistent with the emergence of cardiovascular risk during chronic dosing with NSAIDs. Although deletion of the PGI(2) receptor fosters atherogenesis, the importance of COX-2 during development has constrained the use of conventional knockout (KO) mice to address this question. We developed mice in which COX-2 was deleted postnatally, bypassing cardiorenal defects exhibited by conventional KOs. When crossed into ApoE-deficient hyperlipidemic mice, COX-2 deletion accelerated atherogenesis in both genders, with lesions exhibiting leukocyte infiltration and phenotypic modulation of vascular smooth muscle cells, as reflected by loss of α-smooth muscle cell actin and up-regulation of vascular cell adhesion molecule-1. Stimulated peritoneal macrophages revealed suppression of COX-2-derived prostanoids and augmented 5-lipoxygenase product formation, consistent with COX-2 substrate rediversion. Although deletion of the 5-lipoxygenase activating protein (FLAP) did not influence atherogenesis, it attenuated the proatherogeneic impact of COX-2 deletion in hyperlipidemic mice. Chronic administration of NSAIDs may increasingly confer a cardiovascular hazard on patients at low initial risk. Promotion of atherogenesis by postnatal COX-2 deletion affords a mechanistic explanation for this observation. Coincident inhibition of FLAP may offer an approach to attenuating such a risk from NSAIDs.
Proceedings of the National Academy of Sciences 04/2012; 109(17):6727-32. · 9.68 Impact Factor
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Wen-Liang Song,
Jane Stubbe,
Emanuela Ricciotti,
Naji Alamuddin,
Salam Ibrahim,
Irene Crichton,
Maxwell Prempeh,
John A Lawson,
Robert L Wilensky,
Lars Melholt Rasmussen,
Ellen Puré, Garret A FitzGerald
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ABSTRACT: The clinical use of niacin to treat dyslipidemic conditions is limited by noxious side effects, most commonly facial flushing. In mice, niacin-induced flushing results from COX-1-dependent formation of PGD₂ and PGE₂ followed by COX-2-dependent production of PGE₂. Consistent with this, niacin-induced flushing in humans is attenuated when niacin is combined with an antagonist of the PGD₂ receptor DP1. NSAID-mediated suppression of COX-2-derived PGI₂ has negative cardiovascular consequences, yet little is known about the cardiovascular biology of PGD₂. Here, we show that PGD₂ biosynthesis is augmented during platelet activation in humans and, although vascular expression of DP1 is conserved between humans and mice, platelet DP1 is not present in mice. Despite this, DP1 deletion in mice augmented aneurysm formation and the hypertensive response to Ang II and accelerated atherogenesis and thrombogenesis. Furthermore, COX inhibitors in humans, as well as platelet depletion, COX-1 knockdown, and COX-2 deletion in mice, revealed that niacin evoked platelet COX-1-derived PGD₂ biosynthesis. Finally, ADP-induced spreading on fibrinogen was augmented by niacin in washed human platelets, coincident with increased thromboxane (Tx) formation. However, in platelet-rich plasma, where formation of both Tx and PGD₂ was increased, spreading was not as pronounced and was inhibited by DP1 activation. Thus, PGD₂, like PGI₂, may function as a homeostatic response to thrombogenic and hypertensive stimuli and may have particular relevance as a constraint on platelets during niacin therapy.
The Journal of clinical investigation 03/2012; 122(4):1459-68. · 15.39 Impact Factor
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Richa Saxena,
Clara C Elbers,
Yiran Guo,
Inga Peter,
Tom R Gaunt,
Jessica L Mega,
Matthew B Lanktree,
Archana Tare,
Berta Almoguera Castillo,
Yun R Li, [......],
Paul I W de Bakker,
Jeanne McCaffery,
Cisca Wijmenga,
Marc S Sabatine,
James G Wilson,
Alex Reiner,
Donald W Bowden,
Hakon Hakonarson,
David S Siscovick,
Brendan J Keating
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ABSTRACT: To identify genetic factors contributing to type 2 diabetes (T2D), we performed large-scale meta-analyses by using a custom ∼50,000 SNP genotyping array (the ITMAT-Broad-CARe array) with ∼2000 candidate genes in 39 multiethnic population-based studies, case-control studies, and clinical trials totaling 17,418 cases and 70,298 controls. First, meta-analysis of 25 studies comprising 14,073 cases and 57,489 controls of European descent confirmed eight established T2D loci at genome-wide significance. In silico follow-up analysis of putative association signals found in independent genome-wide association studies (including 8,130 cases and 38,987 controls) performed by the DIAGRAM consortium identified a T2D locus at genome-wide significance (GATAD2A/CILP2/PBX4; p = 5.7 × 10(-9)) and two loci exceeding study-wide significance (SREBF1, and TH/INS; p < 2.4 × 10(-6)). Second, meta-analyses of 1,986 cases and 7,695 controls from eight African-American studies identified study-wide-significant (p = 2.4 × 10(-7)) variants in HMGA2 and replicated variants in TCF7L2 (p = 5.1 × 10(-15)). Third, conditional analysis revealed multiple known and novel independent signals within five T2D-associated genes in samples of European ancestry and within HMGA2 in African-American samples. Fourth, a multiethnic meta-analysis of all 39 studies identified T2D-associated variants in BCL2 (p = 2.1 × 10(-8)). Finally, a composite genetic score of SNPs from new and established T2D signals was significantly associated with increased risk of diabetes in African-American, Hispanic, and Asian populations. In summary, large-scale meta-analysis involving a dense gene-centric approach has uncovered additional loci and variants that contribute to T2D risk and suggests substantial overlap of T2D association signals across multiple ethnic groups.
The American Journal of Human Genetics 02/2012; 90(3):410-25. · 10.60 Impact Factor
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Weisong Zhou,
Dustin R Dowell,
Matthew M Huckabee,
Dawn C Newcomb,
Madison G Boswell,
Kasia Goleniewska,
Matthew T Lotz,
Shinji Toki,
Huiyong Yin,
Songyi Yao,
Chandramohan Natarajan,
Pingsheng Wu,
Subramaniam Sriram,
Richard M Breyer, Garret A Fitzgerald,
R Stokes Peebles
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ABSTRACT: Prostaglandin I(2) (PGI(2)), a lipid mediator currently used in treatment of human disease, is a critical regulator of adaptive immune responses. Although PGI(2) signaling suppressed Th1 and Th2 immune responses, the role of PGI(2) in Th17 differentiation is not known.
In mouse CD4(+)CD62L(+) naïve T cell culture, the PGI(2) analogs iloprost and cicaprost increased IL-17A and IL-22 protein production and Th17 differentiation in vitro. This effect was augmented by IL-23 and was dependent on PGI(2) receptor IP signaling. In mouse bone marrow-derived CD11c(+) dendritic cells (BMDCs), PGI(2) analogs increased the ratio of IL-23/IL-12, which is correlated with increased ability of BMDCs to stimulate naïve T cells for IL-17A production. Moreover, IP knockout mice had delayed onset of a Th17-associated neurological disease, experimental autoimmune encephalomyelitis (EAE), and reduced infiltration of IL-17A-expressing mononuclear cells in the spinal cords compared to wild type mice. These results suggest that PGI(2) promotes in vivo Th17 responses.
The preferential stimulation of Th17 differentiation by IP signaling may have important clinical implications as PGI(2) and its analogs are commonly used to treat human pulmonary hypertension.
PLoS ONE 01/2012; 7(5):e33518. · 4.09 Impact Factor
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Garret A FitzGerald
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ABSTRACT: The rate of new drug approvals in the US has remained essentially constant since 1950, while the costs of drug development have soared. Many commentators question the sustainability of the current model of drug development, in which large pharmaceutical companies incur markedly escalating costs to deliver the same number of products to market. This Issue Brief summarizes the problem, describes ongoing governmental efforts to influence the process, and suggests changes in regulatory science and translational medicine that may promote more successful development of safe and effective therapeutics
LDI issue brief 10/2011; 17(2):1-4.
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ABSTRACT: Inhibition of cyclooxygenase (COX) 2, which is associated with >40% of breast cancers, decreases the risk of tumorigenesis and breast cancer recurrence. To study the role of COX-2 in breast cancer, we engineered mice that lack selectively mammary epithelial cell (MEC) COX-2 (COX-2 KO(MEC)). Compared with wild type (WT), MEC from COX-2 KO(MEC) mice expressed >90% less COX-2 messenger RNA (mRNA) and protein and produced 90% less of the dominant pro-oncogenic COX-2 product, prostaglandin (PG) E(2). We confirmed COX-2 as the principle source of PGE(2) in MEC treated with selective COX-2 and COX-1 inhibitors. Tumors were induced in mice using medroxyprogesterone acetate and 7,12-dimethylbenz[a]anthracene. Breast cancer onset was significantly delayed in COX-2 KO(MEC) compared with WT (P = 0.03), equivalent to the delay following systemic COX-2 inhibition with rofecoxib. Compared with WT, COX-2 KO(MEC) tumors showed increased mRNA for Caspase-3, Ki-67 and common markers for leukocytes (CD45) and macrophages (F4/80). Analysis of multiple markers/cytokines, namely CD86, inducible nitric oxide synthase (iNOS), interleukin-6, tumor necrosis factor α (TNFα) and Tim-3 indicated a shift toward antitumorigenic type 1 immune responses in COX-2 KO(MEC) tumors. Immunohistochemical analysis confirmed elevated expression of CD45, F4/80 and CD86 in COX-2 KO(MEC) tumors. Concordant with a role for COX-2 in restraining M1 macrophage polarization, CD86 and TNFα expression were offset by exogenous PGE(2) in bone marrow-derived macrophages polarized in vitro to the M1 phenotype. Our data reveal the importance of epithelial COX-2 in tumor promotion and indicate that deletion of epithelial COX-2 may skew tumor immunity toward type 1 responses, coincident with delayed tumor development.
Carcinogenesis 07/2011; 32(10):1441-9. · 5.70 Impact Factor
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ABSTRACT: Prostaglandins are lipid autacoids derived from arachidonic acid. They both sustain homeostatic functions and mediate pathogenic mechanisms, including the inflammatory response. They are generated from arachidonate by the action of cyclooxygenase isoenzymes, and their biosynthesis is blocked by nonsteroidal antiinflammatory drugs, including those selective for inhibition of cyclooxygenase-2. Despite the clinical efficacy of nonsteroidal antiinflammatory drugs, prostaglandins may function in both the promotion and resolution of inflammation. This review summarizes insights into the mechanisms of prostaglandin generation and the roles of individual mediators and their receptors in modulating the inflammatory response. Prostaglandin biology has potential clinical relevance for atherosclerosis, the response to vascular injury and aortic aneurysm.
Arteriosclerosis Thrombosis and Vascular Biology 05/2011; 31(5):986-1000. · 6.37 Impact Factor
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Miao Wang,
Kaori Ihida-Stansbury,
Devashish Kothapalli,
Mathieu C Tamby,
Zhou Yu,
Lihong Chen,
Gregory Grant,
Yan Cheng,
John A Lawson,
Richard K Assoian,
Peter L Jones, Garret A Fitzgerald
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ABSTRACT: Microsomal (m) prostaglandin (PG) E₂ synthase (S)-1 catalyzes the formation of PGE₂ from PGH₂, a cyclooxygenase product that is derived from arachidonic acid. Previous studies in mice suggest that targeting mPGES-1 may be less likely to cause hypertension or thrombosis than cyclooxygenase-2-selective inhibition or deletion in vivo. Indeed, deletion of mPGES-1 retards atherogenesis and angiotensin II-induced aortic aneurysm formation. The role of mPGES-1 in the response to vascular injury is unknown.
Mice were subjected to wire injury of the femoral artery. Both neointimal area and vascular stenosis were significantly reduced 4 weeks after injury in mPGES-1 knockout mice compared with wild-type controls (65.6 ± 5.7 versus 37.7 ± 5.1 × 10³ pixel area and 70.5 ± 13.4% versus 47.7 ± 17.4%, respectively; P < 0.01). Induction of tenascin-C, a proproliferative and promigratory extracellular matrix protein, after injury was attenuated in the knockouts. Consistent with in vivo rediversion of PG biosynthesis, mPGES-1-deleted vascular smooth muscle cells generated less PGE₂ but more PGI₂ and expressed reduced tenascin-C compared with wild-type cells. Both suppression of PGE₂ and augmentation of PGI₂ attenuate tenascin-C expression and vascular smooth muscle cell proliferation and migration in vitro.
Deletion of mPGES-1 in mice attenuates neointimal hyperplasia after vascular injury, in part by regulating tenascin-C expression. This raises for consideration the therapeutic potential of mPGES-1 inhibitors as adjuvant therapy for percutaneous coronary intervention.
Circulation 02/2011; 123(6):631-9. · 14.74 Impact Factor
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Stephan Winnik,
Christine Lohmann,
Eva K Richter,
Nicola Schäfer,
Wen-Liang Song,
Florian Leiber,
Pavani Mocharla,
Janin Hofmann,
Roland Klingenberg,
Jan Borén,
Burkhard Becher, Garret A Fitzgerald,
Thomas F Lüscher,
Christian M Matter,
Jürg H Beer
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ABSTRACT: Epidemiological studies report an inverse association between plant-derived dietary α-linolenic acid (ALA) and cardiovascular events. However, little is known about the mechanism of this protection. We assessed the cellular and molecular mechanisms of dietary ALA (flaxseed) on atherosclerosis in a mouse model.
Eight-week-old male apolipoprotein E knockout (ApoE(-/-)) mice were fed a 0.21 % (w/w) cholesterol diet for 16 weeks containing either a high ALA [7.3 % (w/w); n = 10] or low ALA content [0.03 % (w/w); n = 10]. Bioavailability, chain elongation, and fatty acid metabolism were measured by gas chromatography of tissue lysates and urine. Plaques were assessed using immunohistochemistry. T cell proliferation was investigated in primary murine CD3-positive lymphocytes. T cell differentiation and activation was assessed by expression analyses of interferon-γ, interleukin-4, and tumour necrosis factor α (TNFα) using quantitative PCR and ELISA. Dietary ALA increased aortic tissue levels of ALA as well as of the n-3 long chain fatty acids (LC n-3 FA) eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid. The high ALA diet reduced plaque area by 50% and decreased plaque T cell content as well as expression of vascular cell adhesion molecule-1 and TNFα. Both dietary ALA and direct ALA exposure restricted T cell proliferation, differentiation, and inflammatory activity. Dietary ALA shifted prostaglandin and isoprostane formation towards 3-series compounds, potentially contributing to the atheroprotective effects of ALA.
Dietary ALA diminishes experimental atherogenesis and restricts T cell-driven inflammation, thus providing the proof-of-principle that plant-derived ALA may provide a valuable alternative to marine LC n-3 FA.
European Heart Journal 02/2011; 32(20):2573-84. · 10.48 Impact Factor
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Matthew B Lanktree,
Yiran Guo,
Muhammed Murtaza,
Joseph T Glessner,
Swneke D Bailey,
N Charlotte Onland-Moret,
Guillaume Lettre,
Halit Ongen,
Ramakrishnan Rajagopalan,
Toby Johnson, [......],
Wolfgang Koenig,
Tom R Gaunt,
Sonia S Anand,
Yvonne T van der Schouw,
Nicole Soranzo, Garret A Fitzgerald,
Alex Reiner,
Robert A Hegele,
Hakon Hakonarson,
Brendan J Keating
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ABSTRACT: Height is a classic complex trait with common variants in a growing list of genes known to contribute to the phenotype. Using a genecentric genotyping array targeted toward cardiovascular-related loci, comprising 49,320 SNPs across approximately 2000 loci, we evaluated the association of common and uncommon SNPs with adult height in 114,223 individuals from 47 studies and six ethnicities. A total of 64 loci contained a SNP associated with height at array-wide significance (p < 2.4 × 10(-6)), with 42 loci surpassing the conventional genome-wide significance threshold (p < 5 × 10(-8)). Common variants with minor allele frequencies greater than 5% were observed to be associated with height in 37 previously reported loci. In individuals of European ancestry, uncommon SNPs in IL11 and SMAD3, which would not be genotyped with the use of standard genome-wide genotyping arrays, were strongly associated with height (p < 3 × 10(-11)). Conditional analysis within associated regions revealed five additional variants associated with height independent of lead SNPs within the locus, suggesting allelic heterogeneity. Although underpowered to replicate findings from individuals of European ancestry, the direction of effect of associated variants was largely consistent in African American, South Asian, and Hispanic populations. Overall, we show that dense coverage of genes for uncommon SNPs, coupled with large-scale meta-analysis, can successfully identify additional variants associated with a common complex trait.
The American Journal of Human Genetics 01/2011; 88(1):6-18. · 10.60 Impact Factor
