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1.  Loci influencing blood pressure identified using a cardiovascular gene-centric array 
Ganesh, Santhi K. | Tragante, Vinicius | Guo, Wei | Guo, Yiran | Lanktree, Matthew B. | Smith, Erin N. | Johnson, Toby | Castillo, Berta Almoguera | Barnard, John | Baumert, Jens | Chang, Yen-Pei Christy | Elbers, Clara C. | Farrall, Martin | Fischer, Mary E. | Franceschini, Nora | Gaunt, Tom R. | Gho, Johannes M.I.H. | Gieger, Christian | Gong, Yan | Isaacs, Aaron | Kleber, Marcus E. | Leach, Irene Mateo | McDonough, Caitrin W. | Meijs, Matthijs F.L. | Mellander, Olle | Molony, Cliona M. | Nolte, Ilja M. | Padmanabhan, Sandosh | Price, Tom S. | Rajagopalan, Ramakrishnan | Shaffer, Jonathan | Shah, Sonia | Shen, Haiqing | Soranzo, Nicole | van der Most, Peter J. | Van Iperen, Erik P.A. | Van Setten, Jessica | Vonk, Judith M. | Zhang, Li | Beitelshees, Amber L. | Berenson, Gerald S. | Bhatt, Deepak L. | Boer, Jolanda M.A. | Boerwinkle, Eric | Burkley, Ben | Burt, Amber | Chakravarti, Aravinda | Chen, Wei | Cooper-DeHoff, Rhonda M. | Curtis, Sean P. | Dreisbach, Albert | Duggan, David | Ehret, Georg B. | Fabsitz, Richard R. | Fornage, Myriam | Fox, Ervin | Furlong, Clement E. | Gansevoort, Ron T. | Hofker, Marten H. | Hovingh, G. Kees | Kirkland, Susan A. | Kottke-Marchant, Kandice | Kutlar, Abdullah | LaCroix, Andrea Z. | Langaee, Taimour Y. | Li, Yun R. | Lin, Honghuang | Liu, Kiang | Maiwald, Steffi | Malik, Rainer | Murugesan, Gurunathan | Newton-Cheh, Christopher | O'Connell, Jeffery R. | Onland-Moret, N. Charlotte | Ouwehand, Willem H. | Palmas, Walter | Penninx, Brenda W. | Pepine, Carl J. | Pettinger, Mary | Polak, Joseph F. | Ramachandran, Vasan S. | Ranchalis, Jane | Redline, Susan | Ridker, Paul M. | Rose, Lynda M. | Scharnag, Hubert | Schork, Nicholas J. | Shimbo, Daichi | Shuldiner, Alan R. | Srinivasan, Sathanur R. | Stolk, Ronald P. | Taylor, Herman A. | Thorand, Barbara | Trip, Mieke D. | van Duijn, Cornelia M. | Verschuren, W. Monique | Wijmenga, Cisca | Winkelmann, Bernhard R. | Wyatt, Sharon | Young, J. Hunter | Boehm, Bernhard O. | Caulfield, Mark J. | Chasman, Daniel I. | Davidson, Karina W. | Doevendans, Pieter A. | FitzGerald, Garret A. | Gums, John G. | Hakonarson, Hakon | Hillege, Hans L. | Illig, Thomas | Jarvik, Gail P. | Johnson, Julie A. | Kastelein, John J.P. | Koenig, Wolfgang | März, Winfried | Mitchell, Braxton D. | Murray, Sarah S. | Oldehinkel, Albertine J. | Rader, Daniel J. | Reilly, Muredach P. | Reiner, Alex P. | Schadt, Eric E. | Silverstein, Roy L. | Snieder, Harold | Stanton, Alice V. | Uitterlinden, André G. | van der Harst, Pim | van der Schouw, Yvonne T. | Samani, Nilesh J. | Johnson, Andrew D. | Munroe, Patricia B. | de Bakker, Paul I.W. | Zhu, Xiaofeng | Levy, Daniel | Keating, Brendan J. | Asselbergs, Folkert W.
Human Molecular Genetics  2013;22(16):3394-3395.
doi:10.1093/hmg/ddt177
PMCID: PMC3888295
2.  Loci influencing blood pressure identified using a cardiovascular gene-centric array 
Ganesh, Santhi K. | Tragante, Vinicius | Guo, Wei | Guo, Yiran | Lanktree, Matthew B. | Smith, Erin N. | Johnson, Toby | Castillo, Berta Almoguera | Barnard, John | Baumert, Jens | Chang, Yen-Pei Christy | Elbers, Clara C. | Farrall, Martin | Fischer, Mary E. | Franceschini, Nora | Gaunt, Tom R. | Gho, Johannes M.I.H. | Gieger, Christian | Gong, Yan | Isaacs, Aaron | Kleber, Marcus E. | Leach, Irene Mateo | McDonough, Caitrin W. | Meijs, Matthijs F.L. | Mellander, Olle | Molony, Cliona M. | Nolte, Ilja M. | Padmanabhan, Sandosh | Price, Tom S. | Rajagopalan, Ramakrishnan | Shaffer, Jonathan | Shah, Sonia | Shen, Haiqing | Soranzo, Nicole | van der Most, Peter J. | Van Iperen, Erik P.A. | Van Setten, Jessic A. | Vonk, Judith M. | Zhang, Li | Beitelshees, Amber L. | Berenson, Gerald S. | Bhatt, Deepak L. | Boer, Jolanda M.A. | Boerwinkle, Eric | Burkley, Ben | Burt, Amber | Chakravarti, Aravinda | Chen, Wei | Cooper-DeHoff, Rhonda M. | Curtis, Sean P. | Dreisbach, Albert | Duggan, David | Ehret, Georg B. | Fabsitz, Richard R. | Fornage, Myriam | Fox, Ervin | Furlong, Clement E. | Gansevoort, Ron T. | Hofker, Marten H. | Hovingh, G. Kees | Kirkland, Susan A. | Kottke-Marchant, Kandice | Kutlar, Abdullah | LaCroix, Andrea Z. | Langaee, Taimour Y. | Li, Yun R. | Lin, Honghuang | Liu, Kiang | Maiwald, Steffi | Malik, Rainer | Murugesan, Gurunathan | Newton-Cheh, Christopher | O'Connell, Jeffery R. | Onland-Moret, N. Charlotte | Ouwehand, Willem H. | Palmas, Walter | Penninx, Brenda W. | Pepine, Carl J. | Pettinger, Mary | Polak, Joseph F. | Ramachandran, Vasan S. | Ranchalis, Jane | Redline, Susan | Ridker, Paul M. | Rose, Lynda M. | Scharnag, Hubert | Schork, Nicholas J. | Shimbo, Daichi | Shuldiner, Alan R. | Srinivasan, Sathanur R. | Stolk, Ronald P. | Taylor, Herman A. | Thorand, Barbara | Trip, Mieke D. | van Duijn, Cornelia M. | Verschuren, W. Monique | Wijmenga, Cisca | Winkelmann, Bernhard R. | Wyatt, Sharon | Young, J. Hunter | Boehm, Bernhard O. | Caulfield, Mark J. | Chasman, Daniel I. | Davidson, Karina W. | Doevendans, Pieter A. | FitzGerald, Garret A. | Gums, John G. | Hakonarson, Hakon | Hillege, Hans L. | Illig, Thomas | Jarvik, Gail P. | Johnson, Julie A. | Kastelein, John J.P. | Koenig, Wolfgang | März, Winfried | Mitchell, Braxton D. | Murray, Sarah S. | Oldehinkel, Albertine J. | Rader, Daniel J. | Reilly, Muredach P. | Reiner, Alex P. | Schadt, Eric E. | Silverstein, Roy L. | Snieder, Harold | Stanton, Alice V. | Uitterlinden, André G. | van der Harst, Pim | van der Schouw, Yvonne T. | Samani, Nilesh J. | Johnson, Andrew D. | Munroe, Patricia B. | de Bakker, Paul I.W. | Zhu, Xiaofeng | Levy, Daniel | Keating, Brendan J. | Asselbergs, Folkert W.
Human Molecular Genetics  2013;22(8):1663-1678.
Blood pressure (BP) is a heritable determinant of risk for cardiovascular disease (CVD). 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 ∼2100 candidate genes for cardiovascular phenotypes in 61 619 individuals of European ancestry from cohort studies in the USA 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 10 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 < 2.4 × 10−6). We then replicated these associations in an independent set of 65 886 individuals of European ancestry. The findings from expression QTL (eQTL) analysis showed associations of SNPs in the MDM4 region with MDM4 expression. We did not find any evidence of association of the two novel SNPs in MDM4 and HRH1 with sequelae of high BP including coronary artery disease (CAD), left ventricular hypertrophy (LVH) 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.
doi:10.1093/hmg/dds555
PMCID: PMC3657476  PMID: 23303523
4.  Myeloid Cell 5-Lipoxygenase Activating Protein Modulates the Response to Vascular Injury 
Circulation research  2012;112(3):432-440.
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.
Conclusion
Expression of lesional FLAP in myeloid cells promotes LTB4 dependent VSMC phenotypic modulation, intimal migration and proliferation.
doi:10.1161/CIRCRESAHA.112.300755
PMCID: PMC3565603  PMID: 23250985
Restenosis; vascular injury; leukotrienes; inflammation; angioplasty and stenting; smooth muscle cell; animal model of human disease remodeling
5.  Drug Resistance and Pseudoresistance: An Unintended Consequence of Enteric Coating Aspirin 
Circulation  2012;127(3):377-385.
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.
doi:10.1161/CIRCULATIONAHA.112.117283
PMCID: PMC3552520  PMID: 23212718
aspirin; pharmacology; platelets; thromboxane
6.  Cell Selective Cardiovascular Biology of Microsomal Prostaglandin E Synthase-1 
Circulation  2012;127(2):233-243.
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 PGH2 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.
doi:10.1161/CIRCULATIONAHA.112.119479
PMCID: PMC3546279  PMID: 23204105
mPGES-1; vascular injury; vascular smooth muscle cell; endothelial cell; macrophage
7.  Vascular COX-2 Modulates Blood Pressure and Thrombosis in Mice 
Science translational medicine  2012;4(132):10.1126/scitranslmed.3003787.
Prostacyclin (PGI2) 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 PGI2 (PGI-M) in the urine of healthy volunteers. This suggested that NSAIDs might cause adverse cardiovascular events by reducing production of cardioprotective PGI2. This prediction was based on the assumption that the concentration of PGI-M in urine likely reflected vascular production of PGI2 and that other cardioprotective mediators, especially nitric oxide (NO), were not able to compensate for the loss of PGI2. 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 PGI2 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.
doi:10.1126/scitranslmed.3003787
PMCID: PMC3882087  PMID: 22553252
8.  Historical Lessons in Translational Medicine: Cyclooxygenase Inhibition and P2Y12 Antagonism 
Circulation research  2013;112(1):174-194.
The development of drugs that inhibit platelets has been driven by a combination of clinical insights, fundamental science and sheer luck. The process has evolved as the days of stumbling upon therapeutic gems like aspirin have long passed and have been replaced by an arduous process where a drug is designed to target a specific protein implicated in a well-characterized pathophysiological process. Or so we would like to believe. The development of antiplatelet therapy illustrates the importance of understanding the mechanisms of disease and the pharmacology of the compounds we develop, coupled with careful clinical experimentation and observation. And yes, still, a fair bit of luck.
doi:10.1161/CIRCRESAHA.111.300271
PMCID: PMC3572712  PMID: 23287454
Platelet; prostaglandin; aspirin
9.  Molecular Clocks in Pharmacology 
Circadian rhythms regulate a vast array of biological processes and play a fundamental role in mammalian physiology. As a result, considerable diurnal variation in the pharmacokinetics, efficacy, and side effect profiles of many therapeutics has been described. This variation has subsequently been tied to diurnal rhythms in absorption, distribution, metabolism, and excretion, as well as in pharmacodynamic variables, such as target expression. More recently, the molecular basis of circadian rhythmicity has been elucidated with the identification of clock genes, which oscillate in a circadian manner in most cells and tissues and regulate transcription of large sets of genes. Ongoing research efforts are beginning to reveal the critical role of circadian clock genes in the regulation of pharmacologic parameters, as well as the reciprocal impact of drugs on circadian clock function. This chapter will review the role of circadian clocks in the pharmacokinetics and pharmacodynamics of drug response, and provide several examples of the complex regulation of pharmacologic systems by components of the molecular circadian clock.
doi:10.1007/978-3-642-25950-0_10
PMCID: PMC3684693  PMID: 23604482
circadian clock; pharmacology; pharmacokinetics; pharmacodynamics; CLOCK; Bmal1
10.  Circadian clock proteins regulate neuronal redox homeostasis and neurodegeneration 
The Journal of Clinical Investigation  2013;123(12):5389-5400.
Brain aging is associated with diminished circadian clock output and decreased expression of the core clock proteins, which regulate many aspects of cellular biochemistry and metabolism. The genes encoding clock proteins are expressed throughout the brain, though it is unknown whether these proteins modulate brain homeostasis. We observed that deletion of circadian clock transcriptional activators aryl hydrocarbon receptor nuclear translocator–like (Bmal1) alone, or circadian locomotor output cycles kaput (Clock) in combination with neuronal PAS domain protein 2 (Npas2), induced severe age-dependent astrogliosis in the cortex and hippocampus. Mice lacking the clock gene repressors period circadian clock 1 (Per1) and period circadian clock 2 (Per2) had no observed astrogliosis. Bmal1 deletion caused the degeneration of synaptic terminals and impaired cortical functional connectivity, as well as neuronal oxidative damage and impaired expression of several redox defense genes. Targeted deletion of Bmal1 in neurons and glia caused similar neuropathology, despite the retention of intact circadian behavioral and sleep-wake rhythms. Reduction of Bmal1 expression promoted neuronal death in primary cultures and in mice treated with a chemical inducer of oxidative injury and striatal neurodegeneration. Our findings indicate that BMAL1 in a complex with CLOCK or NPAS2 regulates cerebral redox homeostasis and connects impaired clock gene function to neurodegeneration.
doi:10.1172/JCI70317
PMCID: PMC3859381  PMID: 24270424
11.  Microsomal Prostaglandin E2 Synthase-1 Modulates the Response to Vascular Injury 
Circulation  2011;123(6):10.1161/CIRCULATIONAHA.110.973685.
Background
Microsomal (m) prostaglandin (PG) E2 synthase (S)-1 catalyzes the formation of PGE2 from PGH2, a cyclooxygenase (COX) 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 COX-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.
Methods and Results
Mice were subjected to wire injury of the femoral artery. Both neointimal area and vascular stenosis were reduced significantly four weeks after injury in mPGES-1 knock out (KO) mice compared to wild type (WT) controls (65.6±5.7 vs 37.7±5.1×103 pixel area and 70.5±13.4% vs 47.7±17.4%, respectively; p < 0.01). Induction of tenascin C (TN-C) after injury, a pro-proliferative and promigratory extracellular matrix protein, was attenuated in the KOs. Consistent with in vivo rediversion of PG biosynthesis, mPGES-1 deleted vascular smooth muscle cells (VSMC) generated less PGE2, but more PGI2 and expressed reduced TN-C when compared with WT cells. Both suppression of PGE2 and augmentation of PGI2 attenuate TN-C expression, VSMC proliferation and migration in vitro.
Conclusions
Deletion of mPGES-1 in mice attenuates neointimal hyperplasia after vascular injury, in part by regulating TN-C expression. This raises for consideration the therapeutic potential of mPGES-1 inhibitors as adjuvant therapy for percutaneous coronary intervention.
doi:10.1161/CIRCULATIONAHA.110.973685
PMCID: PMC3827687  PMID: 21282500
Injury; percutaneous transluminal coronary angioplasty; prostacyclin; prostaglandins; vascular response
12.  Prostaglandin D2 inhibits wound-induced hair follicle neogenesis through the receptor, Gpr44 
Prostaglandins (PGs) are key inflammatory mediators involved in wound healing and regulating hair growth; however, their role in skin regeneration after injury is unknown. Using wound-induced hair follicle neogenesis (WIHN) as a marker of skin regeneration, we hypothesized that PGD2 decreases follicle neogenesis. PGE2 and PGD2 were elevated early and late respectively during wound healing. The levels of WIHN, lipocalin-type prostaglandin D2 synthase (Ptgds) and its product PGD2 each varied significantly among background strains of mice after wounding and all correlated such that the highest Ptgds and PGD2 levels were associated with the lowest amount of regeneration. Additionally, an alternatively spliced transcript variant of Ptgds missing exon 3 correlated with high regeneration in mice. Exogenous application of PGD2 decreased WIHN in wild type mice and PGD2 receptor Gpr44 null mice showed increased WIHN compared to strain-matched control mice. Furthermore, Gpr44 null mice were resistant to PGD2-induced inhibition of follicle neogenesis. In all, these findings demonstrate that PGD2 inhibits hair follicle regeneration through the Gpr44 receptor and imply that inhibition of PGD2 production or Gpr44 signaling will promote skin regeneration.
doi:10.1038/jid.2012.398
PMCID: PMC3593761  PMID: 23190891
13.  Obesity in mice with adipocyte-specific deletion of clock component Arntl 
Nature medicine  2012;18(12):1768-1777.
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.
doi:10.1038/nm.2979
PMCID: PMC3782286  PMID: 23142819
14.  Prostaglandin I2 promotes the development of IL-17-producing γδ T cells that associate with the epithelium during allergic lung inflammation 
γδ T cells rapidly produce cytokines and represent a first line of defence against microbes and other environmental insults at mucosal tissues and are thus thought to play a local immunoregulatory role. We show that allergic airway inflammation was associated with an increase in innate IL-17-producing γδ T (γδ-17) cells that expressed the αEβ7 integrin and were closely associated with the airway epithelium. Importantly, prostaglandin (PG)I2 and its receptor IP, which downregulated airway eosinophilic inflammation, promoted the emergence of these intraepithelial γδ-17 cells into the airways by enhancing IL-6 production by lung eosinophils and dendritic cells. Accordingly, a pronounced reduction of γδ-17 cells was observed in the thymus of naïve mice lacking the PGI2 receptor IP, as well as in the lungs during allergic inflammation, implying a critical role for PGI2 in the programming of “natural” γδ-17 cells. Conversely, iloprost, a stable analog of PGI2, augmented IL-17 production by γδ T cells but significantly reduced the airway inflammation. Together, these findings suggest that PGI2 plays a key immunoregulatory role by promoting the development of innate intraepithelial γδ-17 cells through an IL-6-dependent mechanism. By enhancing γδ-17 cell responses, stable analogs of PGI2 may be exploited in the development of new immunotherapeutic approaches.
doi:10.4049/jimmunol.1101261
PMCID: PMC3208053  PMID: 21976777
Lung; inflammation; Th2 cells; γδ T cells; IL-17
15.  Deletion of cyclooxygenase 2 in mouse mammary epithelial cells delays breast cancer onset through augmentation of type 1 immune responses in tumors 
Carcinogenesis  2011;32(10):1441-1449.
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 KOMEC). Compared with wild type (WT), MEC from COX-2 KOMEC 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) E2. We confirmed COX-2 as the principle source of PGE2 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 KOMEC compared with WT (P = 0.03), equivalent to the delay following systemic COX-2 inhibition with rofecoxib. Compared with WT, COX-2 KOMEC 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 KOMEC tumors. Immunohistochemical analysis confirmed elevated expression of CD45, F4/80 and CD86 in COX-2 KOMEC tumors. Concordant with a role for COX-2 in restraining M1 macrophage polarization, CD86 and TNFα expression were offset by exogenous PGE2 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.
doi:10.1093/carcin/bgr134
PMCID: PMC3975167  PMID: 21771729
16.  Prostaglandin I2 Signaling Drives Th17 Differentiation and Exacerbates Experimental Autoimmune Encephalomyelitis 
PLoS ONE  2012;7(5):e33518.
Background
Prostaglandin I2 (PGI2), a lipid mediator currently used in treatment of human disease, is a critical regulator of adaptive immune responses. Although PGI2 signaling suppressed Th1 and Th2 immune responses, the role of PGI2 in Th17 differentiation is not known.
Methodology/Principal Findings
In mouse CD4+CD62L+ naïve T cell culture, the PGI2 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 PGI2 receptor IP signaling. In mouse bone marrow-derived CD11c+ dendritic cells (BMDCs), PGI2 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 PGI2 promotes in vivo Th17 responses.
Conclusion
The preferential stimulation of Th17 differentiation by IP signaling may have important clinical implications as PGI2 and its analogs are commonly used to treat human pulmonary hypertension.
doi:10.1371/journal.pone.0033518
PMCID: PMC3349674  PMID: 22590492
17.  Prostaglandins and Inflammation 
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 (COX) isoenzymes and their biosynthesis is blocked by nonsteroidal anti-inflammatory drugs (NSAIDs), including those selective for inhibition of COX-2. Despite the clinical efficacy of NSAIDs, 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.
doi:10.1161/ATVBAHA.110.207449
PMCID: PMC3081099  PMID: 21508345
18.  Prostaglandin D2 Inhibits Hair Growth and Is Elevated in Bald Scalp of Men with Androgenetic Alopecia 
Science Translational Medicine  2012;4(126):126ra34.
Testosterone is necessary for the development of male pattern baldness, known as androgenetic alopecia (AGA); yet, the mechanisms for decreased hair growth in this disorder are unclear. We show that prostaglandin D2 synthase (PTGDS) is elevated at the mRNA and protein levels in bald scalp compared to haired scalp of men with AGA. The product of PTGDS enzyme activity, prostaglandin D2 (PGD2), is similarly elevated in bald scalp. During normal follicle cycling in mice, Ptgds and PGD2 levels increase immediately preceding the regression phase, suggesting an inhibitory effect on hair growth. We show that PGD2 inhibits hair growth in explanted human hair follicles and when applied topically to mice. Hair growth inhibition requires the PGD2 receptor G protein (heterotrimeric guanine nucleotide)–coupled receptor 44 (GPR44), but not the PGD2 receptor 1 (PTGDR). Furthermore, we find that a transgenic mouse, K14-Ptgs2, which targets prostaglandin-endoperoxide synthase 2 expression to the skin, demonstrates elevated levels of PGD2 in the skin and develops alopecia, follicular miniaturization, and sebaceous gland hyperplasia, which are all hallmarks of human AGA. These results define PGD2 as an inhibitor of hair growth in AGA and suggest the PGD2-GPR44 pathway as a potential target for treatment.
doi:10.1126/scitranslmed.3003122
PMCID: PMC3319975  PMID: 22440736
19.  Niacin and biosynthesis of PGD2 by platelet COX-1 in mice and humans  
The Journal of Clinical Investigation  2012;122(4):1459-1468.
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.
doi:10.1172/JCI59262
PMCID: PMC3314457  PMID: 22406532
20.  The cardiovascular biology of microsomal prostaglandin E synthase-1 
Trends in cardiovascular medicine  2010;20(6):189-195.
Both traditional and purpose designed nonsteroidal anti-inflammatory drugs (NSAIDs), selective for inhibition of cyclooxygenase (COX) -2 alleviate pain and inflammation but confer a cardiovascular hazard, attributable to inhibition of COX-2 derived prostacyclin (PGI2). Deletion of microsomal PGE synthase–1 (mPGES-1), the dominant enzyme that converts the COX derived intermediate product, PGH2, to form PGE2, modulates inflammatory pain in rodents. By contrast with COX-2 deletion or inhibition, PGI2 formation is augmented in mPGES-1−/− mice an effect which may confer cardiovascular benefit, yet undermine the analgesic potential of inhibitors of this enzyme. This review will consider the cardiovascular biology of mPGES1, and the complex challenge of developing inhibitors of this enzyme.
doi:10.1016/j.tcm.2011.04.002
PMCID: PMC3235702  PMID: 22137640
Prostaglandin; prostacyclin; PGE synthase–1; cyclooxygenase; cardiovascular; inflammation
21.  Targeted Deletions of COX-2 and Atherogenesis in Mice 
Circulation  2010;121(24):2654-2660.
Background
While the dominant product of vascular cyclooxygenase (COX)-2, prostacyclin (PGI2), restrains atherogenesis, inhibition and deletion of COX-2 have yielded conflicting results in mouse models of atherosclerosis. Floxed mice were used to parse distinct cellular contributions of COX-2 in macrophages (Mac) and T cells (TC) to atherogenesis.
Methods and Results
Deletion of Mac COX-2 (MacKO) was attained using LysMCre mice and suppressed completely lipopolysaccharide (LPS) stimulated Mac prostaglandin (PG) formation and LPS evoked systemic PG biosynthesis by ∼ 30%. LPS stimulated COX-2 expression was suppressed in polymorphonuclear leucocytes (PMN) isolated from MacKOs, but PG formation was not even detected in PMN supernatants from control mice. Atherogenesis was attenuated when MacKOs were crossed into hyperlipidemic LdlR KOs. Deletion of Mac COX-2 appeared to remove a restraint on COX-2 expression in lesional non-leukocyte (CD45 and CD11b negative) vascular cells that express vascular cell adhesion molecule and variably, α-smooth muscle actin and vimentin, portending a shift in PG profile and consequent atheroprotection. Basal expression of COX-2 was minimal in TCs, but use of CD4Cre to generate TC knockouts (TCKOs) depressed its modest upregulation by anti-CD3ε. However, biosynthesis of PGs, TC composition in lymphatic organs and atherogenesis in LDLR KOs were unaltered in TCKOs.
Conclusions
Mac COX-2, primarily a source of thromboxane A2 and PGE2, promotes atherogenesis and exerts a restraint on enzyme expression by lesional cells suggestive of vascular smooth muscle cells, a prominent source of atheroprotective PGI2. TC COX-2 does not influence detectably TC development or function nor atherogenesis in mice.
doi:10.1161/CIRCULATIONAHA.109.910687
PMCID: PMC2909762  PMID: 20530000
Atherosclerosis; Inflammation; Prostaglandins
22.  Circadian clocks and vascular function 
Circulation research  2010;106(5):833-841.
The circadian clock regulates many aspects of physiology including cardiovascular function. Internal oscillators exist in endothelial, smooth muscle cells and fibroblasts of the vasculature. Vascular tone and thrombus formation – two key elements of vascular function in regard to adverse cardiovascular events - exhibit diurnal rhythmicity. In this review, we describe changes in vascular function that result from genetic disruption of discrete elements of the circadian clock.
doi:10.1161/CIRCRESAHA.109.211706
PMCID: PMC2848505  PMID: 20299673
circadian; vasculature; thrombogenesis; vasoreaction
23.  Reengineering the National Clinical and Translational Research Enterprise: The Strategic Plan of the National Clinical and Translational Science Awards Consortium 
Advances in human health require the efficient and rapid translation of scientific discoveries into effective clinical treatments; this process in turn depends upon observational data gathered from patients, communities, and public-health research that can be used to guide basic scientific investigation. Such bidirectional translational science, however, faces unprecedented challenges due to the rapid pace of scientific and technological development, as well as the difficulties of negotiating increasingly complex regulatory and commercial environments that overlap the research domain. Further, numerous barriers to translational science have emerged among the nation’s academic research centers, including basic structural and cultural impediments to innovation and collaboration, shortages of trained investigators, and inadequate funding.
To address these serious and systemic problems, in 2006, the National Institutes of Health created the Clinical and Translational Science Awards (CTSA) program, which aims to catalyze the transformation of biomedical research at a national level, speeding the discovery and development of therapies, fostering collaboration, engaging communities, and training succeeding generations of clinical and translational researchers. The authors report in detail on the planning process, begun in 2008, that was used to engage stakeholders and to identify, refine, and ultimately implement the CTSA program’s overarching strategic goals. They also discuss the implications and likely impact of this strategic planning process as it is applied among the nation’s academic health centers.
doi:10.1097/ACM.0b013e3181ccc877
PMCID: PMC2829722  PMID: 20182119
24.  COX-2 Dependent Prostacyclin Formation and Blood Pressure Homeostasis: Targeted Exchange of COX Isoforms in Mice 
Circulation research  2009;106(2):337.
Rationale
Cyclooxygenase (COX)-derived prostanoids (PGs) are involved in blood pressure (BP) homeostasis. Both traditional(t) nonsteroidal anti-inflammatory drugs (NSAIDs) that inhibit COX-1 and COX-2 and NSAIDs designed to be selective for inhibition of COX-2 cause sodium retention and elevate BP.
Objective
To elucidate the role of COX-2 in BP homeostasis using COX-1>COX-2 mice, in which the COX-1 expression is controlled by COX-2 regulatory elements.
Methods and Results
COX-1>COX-2 mice developed systolic hypertension relative to WTs on a high salt diet (HSD); this was attenuated by a PGI2 receptor (IP) agonist. HSD increased expression of COX-2 in WT mice and of COX-1 in COX-1>COX-2 mice in the inner renal medulla (IM). The HSD augmented in all strains urinary prostanoid metabolite excretion, with the exception of the major PGI2 metabolite that was suppressed on regular chow and unaltered by the HSD in both mutants. Furthermore, IM expression of the receptor for PGI2, but not for other prostanoids, was depressed by HSD in WT and even more so in both mutant strains. Increasing osmolarity augmented expression of COX-2 in WT renal medullary interstitial cells and again the increase in formation of PGI2 observed in WTs was suppressed in cells derived from both mutants. Intramedullary infusion of the IP agonist increased urine volume and sodium excretion in mice.
Conclusion
These studies suggest that dysregulated expression of the COX-2 dependent, PGI2 biosynthesis/response pathway in the IM undermines the homeostatic response to a HSD. Inhibition of this pathway may contribute directly to the hypertensive response to NSAIDs.
doi:10.1161/CIRCRESAHA.109.204529
PMCID: PMC2818801  PMID: 19940265
Cyclooxygenase-2; Nonsteroidal anti-inflammatory drugs; Hypertension; Prostacyclin; IP receptor
25.  Dietary α-linolenic acid diminishes experimental atherogenesis and restricts T cell-driven inflammation 
European Heart Journal  2011;32(20):2573-2584.
Aims
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.
Methods and results
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.
Conclusion
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.
doi:10.1093/eurheartj/ehq501
PMCID: PMC3195262  PMID: 21285075
α-Linolenic acid; Atherosclerosis; Inflammation; Polyunsaturated fatty acids

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