126
|
Abstract
Immune cells called mast cells can hinder rather than help the body's response to dengue virus, which suggests that mast cell products could be used as biomarkers to identify severe forms of the disease.
Collapse
|
127
|
Luna-Gomes T, Bozza PT, Bandeira-Melo C. Eosinophil recruitment and activation: the role of lipid mediators. Front Pharmacol 2013; 4:27. [PMID: 23525348 PMCID: PMC3605515 DOI: 10.3389/fphar.2013.00027] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 02/23/2013] [Indexed: 01/05/2023] Open
Abstract
Eosinophils are effector cells that migrate toward several mediators released at inflammatory sites to perform their multiple functions. The mechanisms driving eosinophil selective accumulation in sites of allergic inflammation are well-established and involve several steps controlled by adhesion molecules, priming agents, chemotactic, and surviving factors. Even though the majority of studies focused on role of protein mediators like IL-5 and eotaxins, lipid mediators also participate in eosinophil recruitment and activation. Among the lipid mediators with distinguish eosinophil recruitment and activation capabilities are platelet activating factor and the eicosanoids, including leukotriene B4, cysteinyl leukotrienes, and prostaglandin D2. In this review, we focused on the role of these four lipid mediators in eosinophil recruitment and activation, since they are recognized as key mediators of eosinophilic inflammatory responses.
Collapse
|
128
|
Yu Z, Ricciotti E, Miwa T, Liu S, Ihida-Stansbury K, Landersberg G, Jones PL, Scalia R, Song W, Assoian RK, FitzGerald GA. Myeloid cell 5-lipoxygenase activating protein modulates the response to vascular injury. Circ Res 2013; 112:432-40. [PMID: 23250985 PMCID: PMC3565603 DOI: 10.1161/circresaha.112.300755] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 12/17/2012] [Indexed: 11/16/2022]
Abstract
RATIONALE Human genetics have implicated the 5-lipoxygenase enzyme in the pathogenesis of cardiovascular disease, and an inhibitor of the 5-lipoxygenase 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 mice and wild-type controls. Both neointimal hyperplasia and the intima/media ratio of the injured artery were significantly reduced in the FLAP knockouts, whereas endothelial integrity was preserved. Lesional myeloid cells were depleted and vascular smooth muscle cell (VSMC) proliferation, as reflected by bromodeoxyuridine incorporation, was markedly attenuated by FLAP deletion. Inflammatory cytokine release from FLAP knockout macrophages was depressed, and their restricted ability to induce VSMC migration ex vivo was rescued with leukotriene B(4). FLAP deletion restrained injury and attenuated upregulation of the extracellular matrix protein, tenascin C, 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-1 was also suppressed in FLAP knockout mice. Transplantation of FLAP-replete myeloid cells rescued the proliferative response to vascular injury. CONCLUSIONS Expression of lesional FLAP in myeloid cells promotes leukotriene B(4)-dependent VSMC phenotypic modulation, intimal migration, and proliferation.
Collapse
MESH Headings
- 5-Lipoxygenase-Activating Proteins/deficiency
- 5-Lipoxygenase-Activating Proteins/genetics
- 5-Lipoxygenase-Activating Proteins/metabolism
- Animals
- Bone Marrow Transplantation
- Cell Movement
- Cell Proliferation
- Cells, Cultured
- Cysteine/metabolism
- Disease Models, Animal
- Endothelial Cells/metabolism
- Endothelial Cells/pathology
- Femoral Artery/enzymology
- Femoral Artery/injuries
- Femoral Artery/pathology
- Genotype
- Hyperplasia
- Inflammation Mediators/metabolism
- Leukotriene B4/metabolism
- Leukotrienes/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/immunology
- Muscle, Smooth, Vascular/injuries
- Muscle, Smooth, Vascular/pathology
- Myeloid Cells/enzymology
- Myeloid Cells/immunology
- Myeloid Cells/transplantation
- Myocytes, Smooth Muscle/enzymology
- Myocytes, Smooth Muscle/immunology
- Myocytes, Smooth Muscle/pathology
- Neointima
- Phenotype
- Tenascin/metabolism
- Time Factors
- Vascular Cell Adhesion Molecule-1/metabolism
- Vascular System Injuries/enzymology
- Vascular System Injuries/genetics
- Vascular System Injuries/immunology
- Vascular System Injuries/pathology
- Vascular System Injuries/prevention & control
Collapse
|
129
|
Randomized placebo-controlled intervention with n-3 LC-PUFA-supplemented yoghurt: effects on circulating eicosanoids and cardiovascular risk factors. Clin Nutr 2012; 32:686-96. [PMID: 23332800 DOI: 10.1016/j.clnu.2012.12.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 11/22/2012] [Accepted: 12/05/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND & AIMS The study examined the value of n-3 LC-PUFA-enriched yogurt as means of improving cardiovascular health. DESIGN Fifty three mildly hypertriacylglycerolemic subjects (TAG ≥ 1.7 mmol/L) participated in a randomized, placebo-controlled, double-blind, parallel designed study. The subjects consumed 1) control yoghurt; 2) yoghurt enriched with 0.8 g n-3 LC-PUFA/d; or 3) yoghurt enriched with 3 g n-3 LC-PUFA/d for a period of 10 wks. Blood samples were taken at the beginning and the end of the study period. RESULTS Following daily intake of 3 g n-3 LC-PUFA for 10 weeks, n-3 LC-PUFA levels increased significantly in plasma and red blood cells (RBC) with concomitant increase in the EPA-derived mediators (PGE₃, 12-, 15-, 18-HEPE) in plasma whilst cardiovascular risk factors such as HDL, TAG, AA/EPA ratio, and n-3 index were improved (P < 0.05); the decrease of TAG and increase in HDL were associated with the CD36 genotype. CONCLUSION The observed increase of n-3 LC-PUFA in RBC and plasma lipids due to intake of n-3 LC-PUFA enriched yoghurt resulted in a reduction of cardiovascular risk factors and inflammatory mediators showing that daily consumption of n-3 PUFA enriched yoghurt can be an effective way of supplementing the daily diet and improving cardiovascular health.
Collapse
|
130
|
Consequences of essential fatty acids. Nutrients 2012; 4:1338-57. [PMID: 23112921 PMCID: PMC3475243 DOI: 10.3390/nu4091338] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 08/18/2012] [Accepted: 09/13/2012] [Indexed: 12/17/2022] Open
Abstract
Essential fatty acids (EFA) are nutrients that form an amazingly large array of bioactive mediators that act on a large family of selective receptors. Nearly every cell and tissue in the human body expresses at least one of these receptors, allowing EFA-based signaling to influence nearly every aspect of human physiology. In this way, the health consequences of specific gene-environment interactions with these nutrients are more extensive than often recognized. The metabolic transformations have similar competitive dynamics for the n-3 and n-6 homologs when converting dietary EFA from the external environment of foods into the highly unsaturated fatty acid (HUFA) esters that accumulate in the internal environment of cells and tissues. In contrast, the formation and action of bioactive mediators during tissue responses to stimuli tend to selectively create more intense consequences for n-6 than n-3 homologs. Both n-3 and n-6 nutrients have beneficial actions, but many common health disorders are undesired consequences of excessive actions of tissue n-6 HUFA which are preventable. This review considers the possibility of preventing imbalances in dietary n-3 and n-6 nutrients with informed voluntary food choices. That action may prevent the unintended consequences that come from eating imbalanced diets which support excessive chronic actions of n-6 mediators that harm human health. The consequences from preventing n-3 and n-6 nutrient imbalances on a nationwide scale may be very large, and they need careful evaluation and implementation to avoid further harmful consequences for the national economy.
Collapse
|
131
|
Gilbert NC, Rui Z, Neau DB, Waight MT, Bartlett SG, Boeglin WE, Brash AR, Newcomer ME. Conversion of human 5-lipoxygenase to a 15-lipoxygenase by a point mutation to mimic phosphorylation at Serine-663. FASEB J 2012; 26:3222-9. [PMID: 22516296 PMCID: PMC3405276 DOI: 10.1096/fj.12-205286] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 04/10/2012] [Indexed: 01/09/2023]
Abstract
The enzyme 5-lipoxygenase (5-LOX) initiates biosynthesis of the proinflammatory leukotriene lipid mediators and, together with 15-LOX, is also required for synthesis of the anti-inflammatory lipoxins. The catalytic activity of 5-LOX is regulated through multiple mechanisms, including Ca(2+)-targeted membrane binding and phosphorylation at specific serine residues. To investigate the consequences of phosphorylation at S663, we mutated the residue to the phosphorylation mimic Asp, providing a homogenous preparation suitable for catalytic and structural studies. The S663D enzyme exhibits robust 15-LOX activity, as determined by spectrophotometric and HPLC analyses, with only traces of 5-LOX activity remaining; synthesis of the anti-inflammatory lipoxin A(4) from arachidonic acid is also detected. The crystal structure of the S663D mutant in the absence and presence of arachidonic acid (in the context of the previously reported Stable-5-LOX) reveals substantial remodeling of helices that define the active site so that the once fully encapsulated catalytic machinery is solvent accessible. Our results suggest that phosphorylation of 5-LOX at S663 could not only down-regulate leukotriene synthesis but also stimulate lipoxin production in inflammatory cells that do not express 15-LOX, thus redirecting lipid mediator biosynthesis to the production of proresolving mediators of inflammation.
Collapse
|
132
|
Pillai PS, Leeson S, Porter TF, Owens CD, Kim JM, Conte MS, Serhan CN, Gelman S. Chemical mediators of inflammation and resolution in post-operative abdominal aortic aneurysm patients. Inflammation 2012; 35:98-113. [PMID: 21286796 PMCID: PMC3123666 DOI: 10.1007/s10753-011-9294-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Temporal-metabolomic studies of local mediators during inflammation and its resolution uncovered novel pathways and mediators, e.g., lipoxins, resolvins, and protectins that stimulate key resolution responses. Since these studies were carried out with isolated human cells and in animal models, it is important to determine in humans whether temporal profiles between pro-inflammatory mediators and pro-resolving mediators are demonstrable in vivo. To this end, we examined patients undergoing abdominal aortic aneurysm (AAA) surgery. Profiles of mediators including eicosanoids were assessed in addition to pro-resolving mediators. The results demonstrate temporal relationships for local-acting peptides (e.g., VEGF, IL-10, TGF(β)) and lipid mediators (leukotrienes and resolvins). In addition, profiles obtained for AAA patients divided into two groups based on their temporal profile: one group consistent with a pro-inflammatory and another with a resolving profile. Together, these translational metabolomic profiles demonstrate for the first time the temporal relationships between local mediators in humans relevant in inflammation resolution.
Collapse
|
133
|
Peres-Buzalaf C, de Paula L, Frantz F, Soares E, Medeiros A, Peters-Golden M, Silva C, Faccioli L. Control of experimental pulmonary tuberculosis depends more on immunostimulatory leukotrienes than on the absence of immunosuppressive prostaglandins. Prostaglandins Leukot Essent Fatty Acids 2011; 85:75-81. [PMID: 21621991 PMCID: PMC3397385 DOI: 10.1016/j.plefa.2011.04.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 04/11/2011] [Accepted: 04/20/2011] [Indexed: 11/30/2022]
Abstract
Prostaglandins (PGs) and leukotrienes (LTs) are produced in Mycobacterium tuberculosis (Mtb)-infected lungs and have immune suppressive and protective effects, respectively. Considering that both of these mediators are produced during mycobacterial infection, we investigated the specific and relative biological importance of each in regulating host response in experimental tuberculosis. Administration of celecoxib, which was found to reduce lung levels of PGE(2) and increase LTB(4), enhanced the 60-day survival of Mtb-infected mice in 14%. However administration of MK-886, which reduced levels of LTB(4) but did not enhance PGE(2), reduced 60-day survival from 86% to 43% in Mtb-infected mice, and increased lung bacterial burden. MK-886 plus celecoxib reduced survival to a lesser extent than MK-886 alone. MK-886- and MK-886 plus celecoxib-treated animals exhibited reduced levels of the protective interleukin-12 and gamma-interferon. Our findings indicate that in this model, the protective effect of LTs dominates over the suppressive effect of PGs.
Collapse
|
134
|
Montuschi P. Role of Leukotrienes and Leukotriene Modifiers in Asthma. Pharmaceuticals (Basel) 2010; 3:1792-1811. [PMID: 27713330 PMCID: PMC4033953 DOI: 10.3390/ph3061792] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 05/13/2010] [Accepted: 05/31/2010] [Indexed: 12/19/2022] Open
Abstract
Leukotrienes (LTs), including cysteinyl LTs (CysLTs) and LTB₄, are potent lipid mediators that are pivotal in the pathophysiology of asthma phenotypes. At least two receptor subtypes for CysLTs - CysLT1 and CysLT₂ - have been identified. Most of the pathophysiological effects of CysLTs in asthma, including increased airway smooth muscle activity, microvascular permeability and airway mucus secretion, are mediated by the activation of the CysLT1 receptor. LTB₄ may have a role in the development of airway hyperresponsiveness, severe asthma and asthma exacerbations. Although generally less effective than inhaled glucocorticoids, CysLT₁ receptor antagonists can be given orally as monotherapy in patients with persistent mild asthma. In patients with more severe asthma, CysLT₁ receptor antagonists can be combined with inhaled glucocorticoids. This therapeutic strategy improves asthma control and enables the dose of inhaled glucocorticoids to be reduced, while maintaining similar efficacy. The identification of subgroups of patients with asthma who respond to CysLT₁ receptor antagonists is relevant for asthma management, as the response to these drugs is variable. The potential anti-remodeling effect of CysLT₁ receptor antagonists might be important for preventing or reversing airway structural changes in patients with asthma. This review discusses the role of LTs in asthma and the therapeutic implications of the pharmacological modulation of the LT pathway for asthma.
Collapse
|
135
|
Pezzilli R, Morselli-Labate AM, Corinaldesi R. NSAIDs and Acute Pancreatitis: A Systematic Review. Pharmaceuticals (Basel) 2010; 3:558-571. [PMID: 27713268 PMCID: PMC4033969 DOI: 10.3390/ph3030558] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2010] [Revised: 02/11/2010] [Accepted: 03/09/2010] [Indexed: 12/14/2022] Open
Abstract
The resulting pain is the main symptom of acute pancreatitis and it should be alleviated as soon as possible. NSAIDs are the first line therapy for pain and they are generally administered to acute pancreatitis patients upon admission to the hospital. In addition, these drugs have also been used to prevent post-endoscopic cholangiopancreatography (ERCP) acute pancreatitis. On the other hand, there are several reports indicating that NSAIDs may be the actual cause of acute pancreatitis. We carried out a literature search on PubMed/MEDLINE; all full text papers published in from January 1966 to November 2009 on the use of NSAIDs in acute pancreatitis were collected; the literature search was also supplemented by a review of the bibliographies of the papers evaluated. Thus, in this article, we will systematically review the current literature in order to better illustrate the role of NSAIDs in acute pancreatitis, in particular: i) NSAIDs as a cause of acute pancreatitis; ii) their use to prevent post-retrograde ERCP pancreatitis and iii) their efficacy for pain relief in the acute illness of the pancreas.
Collapse
|
136
|
Steinbrink SD, Pergola C, Bühring U, George S, Metzner J, Fischer AS, Häfner AK, Wisniewska JM, Geisslinger G, Werz O, Steinhilber D, Maier TJ. Sulindac sulfide suppresses 5-lipoxygenase at clinically relevant concentrations. Cell Mol Life Sci 2010; 67:797-806. [PMID: 20091083 PMCID: PMC11115735 DOI: 10.1007/s00018-009-0206-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Revised: 10/25/2009] [Accepted: 11/06/2009] [Indexed: 11/30/2022]
Abstract
Sulindac is a non-selective inhibitor of cyclooxygenases (COX) used to treat inflammation and pain. Additionally, non-COX targets may account for the drug's chemo-preventive efficacy against colorectal cancer and reduced gastrointestinal toxicity. Here, we demonstrate that the pharmacologically active metabolite of sulindac, sulindac sulfide (SSi), targets 5-lipoxygenase (5-LO), the key enzyme in the biosynthesis of proinflammatory leukotrienes (LTs). SSi inhibited 5-LO in ionophore A23187- and LPS/fMLP-stimulated human polymorphonuclear leukocytes (IC(50) approximately 8-10 microM). Importantly, SSi efficiently suppressed 5-LO in human whole blood at clinically relevant plasma levels (IC(50) = 18.7 microM). SSi was 5-LO-selective as no inhibition of related lipoxygenases (12-LO, 15-LO) was observed. The sulindac prodrug and the other metabolite, sulindac sulfone (SSo), failed to inhibit 5-LO. Mechanistic analysis demonstrated that SSi directly suppresses 5-LO with an IC(50) of 20 muM. Together, these findings may provide a novel molecular basis to explain the COX-independent pharmacological effects of sulindac under therapy.
Collapse
|
137
|
Carver TW. Exercise-induced asthma: critical analysis of the protective role of montelukast. J Asthma Allergy 2009; 2:93-103. [PMID: 21437147 PMCID: PMC3048606 DOI: 10.2147/jaa.s7321] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Indexed: 11/29/2022] Open
Abstract
Exercise-induced asthma/exercise-induced bronchospasm (EIA/EIB) is a prevalent and clinically important disease affecting young children through older adulthood. These terms are often used interchangeably and the differences are not clearly defined in the literature. The pathogenesis of EIA/EIB may be different in those with persistent asthma compared to those with exercise-induced symptoms only. The natural history of EIA is unclear and may be different for elite athletes. Leukotriene biology has helped the understanding of EIB. The type and intensity of exercise are important factors for EIB. Exercise participation is necessary for proper development and control of EIA is recommended. Symptoms of EIB should be confirmed by proper testing. Biologic markers may also be helpful in diagnosis. Not all exercise symptoms are from EIB. Many medication and nonpharmacologic treatments are available. Asthma education is an important component of managing EIA. Many medications have been tested and the comparisons are complicated. Montelukast is a US Food and Drug Administration-approved asthma and EIB controller and has a number of potential advantages to other asthma medications including short onset of action, ease of use, and lack of tolerance. Not all patients improve with montelukast and rescue medication should be available.
Collapse
|
138
|
Kemp JP. Exercise-induced bronchoconstriction: The effects of montelukast, a leukotriene receptor antagonist. Ther Clin Risk Manag 2009; 5:923-33. [PMID: 20011246 PMCID: PMC2789687 DOI: 10.2147/tcrm.s4830] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Exercise-induced bronchoconstriction (EIB) is very common in both patients with asthma and those who are otherwise thought to be normal. The intensity of exercise as well as the type of exercise is important in producing symptoms. This may make some types of exercise such as swimming more suitable and extended running more difficult for patients with this condition. A better understanding of EIB will allow the physician to direct the patient towards a type of exercise and medications that can result in a more active lifestyle without the same concern for resulting symptoms. This is especially important for schoolchildren who are usually enrolled in physical education classes and elite athletes who may desire to participate in competitive sports. Fortunately several medications (short- and long-acting beta(2)-agonists, cromolyn, nedocromil, inhaled corticosteroids, and more recently leukotriene modifiers) have been shown to be effective in preventing or attenuating the effects of exercise in many patients. In addition, inhaled beta(2)-agonists have been shown to quickly reverse the airway obstruction that develops in patients and continue to be the reliever medications of choice. Inhaled corticosteroids are increasingly being recommended as regular therapy now that the role of inflammation and airway injury has been identified in EIB. With the discovery that there is a release of mediators such as histamine and leukotrienes from cells in the airway following exercise with resulting airway obstruction in susceptible individuals, interest has turned to attenuating their effects with mediator antagonists especially those that block the effects of leukotrienes. Studies with an oral leukotriene antagonist, montelukast, have shown beneficial effects in adults and children aged as young as 6 years with EIB. These effects can be demonstrated as soon as two hours and as long as 24 hours after administration without a demonstrated loss of a protective effect after months of treatment. The studies leading up to and resulting in an approval of montelukast for EIB for patients aged 15 years and older are reviewed in this paper.
Collapse
|
139
|
Mans BJ, Ribeiro JMC. A novel clade of cysteinyl leukotriene scavengers in soft ticks. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2008; 38:862-70. [PMID: 18675910 PMCID: PMC2583325 DOI: 10.1016/j.ibmb.2008.06.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2008] [Revised: 06/26/2008] [Accepted: 06/27/2008] [Indexed: 05/08/2023]
Abstract
Inflammation is an important vertebrate defense mechanism against ecto-parasites for which ticks have evolved numerous mechanisms of modulation. AM-33 and TSGP4, related lipocalins from the soft ticks Argas monolakensis and Ornithodoros savignyi bind cysteinyl leukotrienes with high affinity as measured by isothermal titration calorimetry. This was confirmed in a smooth muscle bioassay that measured contraction of guinea pig ileum induced by leukotriene C4 where both proteins inhibited contraction effectively. Conservation of this function in two diverse soft tick genera suggests that scavenging of cysteinyl leukotrienes evolved in the ancestral soft tick lineage. In addition soft ticks also evolved mechanisms that target other mediators of inflammation that include scavenging of histamine, serotonin, leukotriene B4, thromboxane A2, ATP and inhibition of the complement cascade. Inhibitors of blood-coagulation and platelet aggregation were also present in the ancestral soft tick lineage. Because histamine and cysteinyl leukotrienes are mainly produced by mast cells and basophils, and these cells are important in the mediation of tick rejection reactions, these findings indicate an ancient antagonistic relationship between ticks and the immune system. As such, modulation of the hemostatic system as well as inflammation was important adaptive responses in the evolution of a blood-feeding lifestyle in soft ticks.
Collapse
|
140
|
Talukder JR, Kekuda R, Saha P, Sundaram U. Mechanism of leukotriene D4 inhibition of Na-alanine cotransport in intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2008; 295:G1-G6. [PMID: 18436626 PMCID: PMC2494717 DOI: 10.1152/ajpgi.00498.2007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Accepted: 04/17/2008] [Indexed: 01/31/2023]
Abstract
In a rabbit model of chronic intestinal inflammation, we previously demonstrated inhibition of neutral Na-amino acid cotransport. The mechanism of the inhibition was secondary to a decrease in the affinity for amino acid rather than the number of cotransporters. Since leukotriene (LT)D4 is known to be elevated in enterocytes during chronic intestinal inflammation, we used rat intestinal epithelial cell (IEC-18) monolayers to determine the mechanism of regulation of Na-alanine cotransport (alanine, serine, cysteine transporter 1: ASCT1) by LTD4. Na-alanine cotransport was inhibited by LTD4 in IEC-18 cells. The mechanism of inhibition of ASCT1 (solute carrier, SLC1A4) by LTD4 is secondary to a decrease in the affinity of the cotransporter for alanine without a significant change in cotransporter numbers and is not secondary to an alteration in the Na+ extruding capacity of the cells. Real-time quantitative PCR and Western blot analysis results indicate that ASCT1 message and protein levels are also unchanged in LTD4-treated IEC-18 cells. These results indicate that LTD4 inhibits Na-dependent neutral amino acid cotransport in IEC. The mechanism of inhibition is secondary to a decrease in the affinity for alanine, which is identical to that seen in villus cells from the chronically inflamed rabbit small intestine, where LTD4 levels are significantly increased.
Collapse
|
141
|
Urek MC, Kujundzić M, Banić M, Urek R, Veic TS, Kardum D. Leukotriene receptor antagonists as potential steroid sparing agents in a patient with serosal eosinophilic gastroenteritis. Gut 2006; 55:1363-4. [PMID: 16905705 PMCID: PMC1860023 DOI: 10.1136/gut.2006.099465] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|
142
|
Zeldin DC, Eggleston P, Chapman M, Piedimonte G, Renz H, Peden D. How exposures to biologics influence the induction and incidence of asthma. ENVIRONMENTAL HEALTH PERSPECTIVES 2006; 114:620-6. [PMID: 16581556 PMCID: PMC1440791 DOI: 10.1289/ehp.8379] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A number of environmental factors can affect the development and severity of allergy and asthma; however, it can be argued that the most significant inhaled agents that modulate the development of these conditions are biologics. Sensitization to environmental allergens is an important risk factor for the development of asthma. Innate immune responses are often mediated by receptors on mononuclear cells whose primary ligands arise from microorganisms. Many pathogens, especially viruses, target epithelial cells and affect the host immune response to those pathogens. The acquired immune response to an allergen is influenced by the nature of the innate immune system. Products of innate immune responses to microbes promote T(H)1-acquired responses. In the absence of T(H)1 responses, T(H)2 responses can dominate. Central to T(H)1/T(H)2 balance is the composition of contaminants that derive from microbes. In this review we examine the biology of the response to allergens, viruses, and bacterial products in the context of the development of allergy and asthma.
Collapse
|
143
|
Abstract
Aspirin-induced asthma (AIA) and aspirin-induced urticaria/ angioedema (AIU) are two major aspirin-related allergies. We summarize recent findings related to their molecular genetic mechanisms in order to identify genetic susceptibility markers for differentiating AIU and AIA. The overproduction of cysteinyl leukotriene has been suggested as a mechanism in both AIU and AIA. Increased expression of CYSLTR1 with CYLSTR1 and CYSLTR2 polymorphisms are new findings in AIA, while the ALOX5 promoter polymorphism has been noted in AIU. An HLA study suggested that DPB1*0301 is a strong genetic marker for AIA, and that HLA DRB1*1302 and DQB1*0609 are markers for AIU susceptibility. Several single nucleotide polymorphisms (SNPs) in the promoters of EP2, TBX21, COX-2, Fc epsilon RIbeta, and TBXA2R were associated with AIA, while an Fc epsilon RIalpha promoter polymorphism was associated with AIU. The functional studies of the key genes involved in AIA and AIU are summarized. The identification and functional study of genetic markers for AIA and AIU susceptibility would further elucidate the pathogenic mechanisms and facilitate the development of early diagnostic markers to establish therapeutic targets.
Collapse
|
144
|
Kim SH, Choi JH, Holloway JW, Suh CH, Nahm DH, Ha EH, Park CS, Park HS. Leukotriene-related gene polymorphisms in patients with aspirin-intolerant urticaria and aspirin-intolerant asthma: differing contributions of ALOX5 polymorphism in Korean population. J Korean Med Sci 2005; 20:926-31. [PMID: 16361798 PMCID: PMC2779320 DOI: 10.3346/jkms.2005.20.6.926] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pathogenesis of aspirin (acetylsalicylic acid, ASA)-intolerant urticaria (AIU) is still poorly understood but it has recently been suggested that it is associated with the overproduction of leukotriene (LT). This is supported by evidence that cyclooxygenase 2 inhibitor is given safely to patients with AIU. The present study was designed to investigate the role of genetic polymorphism of LT related genes in the pathogenesis of AIU via a case-control study. We screened single nucleotide polymorphisms (SNPs) in genes encoding enzymes involved in leukotriene synthesis in the Korean population with AIU (n = 101), ASA-intolerant asthma (AIA, n = 95) and normal healthy controls (n = 123). Genotype was determined by primer extension reactions using the SNapShot ddNTP primer extension kit. Among 8 SNPs of four LT related genes, the polymorphism of ALOX5 at positions of -1708 G > A showed significant difference in genotype frequency between AIU and AIA (p = 0.01). Furthermore, there were significant differences observed in the frequencies of two ALOX5 haplotypes between the AIU group and AIA group (p < 0.05). However, there were no differences in allele, genotype, or haplotype frequencies of ALOX5 between the AIU group and the normal control group. These results suggested that ALOX5 has a differing contribution in two major clinical pathogenesis related to ASA-sensitivity.
Collapse
|
145
|
Caironi P, Ichinose F, Liu R, Jones RC, Bloch KD, Zapol WM. 5-Lipoxygenase deficiency prevents respiratory failure during ventilator-induced lung injury. Am J Respir Crit Care Med 2005; 172:334-43. [PMID: 15894604 PMCID: PMC2718472 DOI: 10.1164/rccm.200501-034oc] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2005] [Accepted: 05/04/2005] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Mechanical ventilation with high VT (HVT) progressively leads to lung injury and decreased efficiency of gas exchange. Hypoxic pulmonary vasoconstriction (HPV) directs blood flow to well-ventilated lung regions, preserving systemic oxygenation during pulmonary injury. Recent experimental studies have revealed an important role for leukotriene (LT) biosynthesis by 5-lipoxygenase (5LO) in the impairment of HPV by endotoxin. OBJECTIVES To investigate whether or not impairment of HPV contributes to the hypoxemia associated with HVT and to evaluate the role of LTs in ventilator-induced lung injury. METHODS We studied wild-type and 5LO-deficient mice ventilated for up to 10 hours with low VT (LVT) or HVT. RESULTS In wild-type mice, HVT, but not LVT, increased pulmonary vascular permeability and edema formation, impaired systemic oxygenation, and reduced survival. HPV, as reflected by the increase in left pulmonary vascular resistance induced by left mainstem bronchus occlusion, was markedly impaired in animals ventilated with HVT. HVT ventilation increased bronchoalveolar lavage levels of LTs and neutrophils. In 5LO-deficient mice, the HVT-induced increase of pulmonary vascular permeability and worsening of respiratory mechanics were markedly attenuated, systemic oxygenation was preserved, and survival increased. Moreover, in 5LO-deficient mice, HVT ventilation did not impair the ability of left mainstem bronchus occlusion to increase left pulmonary vascular resistance. Administration of MK886, a 5LO-activity inhibitor, or MK571, a selective cysteinyl-LT(1) receptor antagonist, largely prevented ventilator-induced lung injury. CONCLUSIONS These results indicate that LTs play a central role in the lung injury and impaired oxygenation induced by HVT ventilation.
Collapse
|
146
|
McDanel DL, Muller BA. The linkage between Churg-Strauss syndrome and leukotriene receptor antagonists: fact or fiction? Ther Clin Risk Manag 2005; 1:125-40. [PMID: 18360552 PMCID: PMC1661620 DOI: 10.2147/tcrm.1.2.125.62913] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Epidemiologic evidence has shown that the worldwide prevalence of asthma is increasing. The leukotriene receptor antagonists (LTRAs) represent a new class of therapy for asthma. They have been developed in the last decade and play a pivotal steroid-sparing role in treating the inflammatory component of asthma. Consequently, reports of Churg-Strauss syndrome (CSS), a rare form of systemic vasculitis, have been recognized as a potential side effect in individuals with moderate to severe asthma on LTRA therapy. The serious nature of this disorder is worthy of prompt recognition by clinicians and aggressive therapy to avoid the subsequent longstanding effects of vasculitis. To validate the postulated linkage between the LTRAs and CSS, this review comprehensively evaluates reported cases in the literature and supports a pathophysiological relationship between the LTRAs and the development of CSS.
Collapse
|
147
|
Mayer K, Fegbeutel C, Hattar K, Sibelius U, Krämer HJ, Heuer KU, Temmesfeld-Wollbrück B, Gokorsch S, Grimminger F, Seeger W. Omega-3 vs. omega-6 lipid emulsions exert differential influence on neutrophils in septic shock patients: impact on plasma fatty acids and lipid mediator generation. Intensive Care Med 2003; 29:1472-81. [PMID: 12897994 PMCID: PMC7187949 DOI: 10.1007/s00134-003-1900-2] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2002] [Accepted: 06/03/2003] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To compare the effects of a conventional omega-6 lipid infusion and a fish oil based (omega-3) lipid infusion for parenteral nutrition on neutrophil function, lipid mediators, and plasma free fatty acids. DESIGN AND SETTING Open-label, randomized, pilot study in a university hospital medical intensive care unit and experimental laboratory. PATIENTS AND PARTICIPANTS Ten patients with septic shock and eight healthy controls. INTERVENTIONS Patients (five per group) requiring parenteral nutrition received intravenously either a omega-3 or a omega-6 lipid emulsion for a 10-day period. MEASUREMENTS AND RESULTS At baseline levels of plasma free fatty acids were elevated several-fold, including high concentrations of the omega-6 lipid precursor arachidonic acid (AA). Neutrophils isolated from septic patients displayed markedly reduced responsiveness to ex vivo stimulation, including lipid mediator generation [leukotrienes (LT), PAF], respiratory burst, and phosphoinositide hydrolysis signaling. Under the omega-6 lipid infusion regimen abnormalities in plasma free fatty acids and impairment of neutrophil functions persisted or worsened. In contrast, a rapid switch in the plasma free fatty acid fraction to predominance of the omega-3 acids eicosapentaenoic acid and docosahexaenoic acid over AA occurred in response to omega-3 lipid infusion. LTB(5), in addition to LTB(4), appeared upon neutrophil stimulation originating from these patients, and neutrophil function was significantly improved in the omega-3 lipid group. CONCLUSIONS omega-3 vs. omega-6 lipid emulsions differentially influence the plasma free fatty acid profile with impact on neutrophil functions. Lipid-based parenteral nutrition in septic patients may thus exert profound influence on sequelae and status of immunocompetence and inflammation.
Collapse
|
148
|
Murray J, Ward C, O'Flaherty JT, Dransfield I, Haslett C, Chilvers ER, Rossi AG. Role of leukotrienes in the regulation of human granulocyte behaviour: dissociation between agonist-induced activation and retardation of apoptosis. Br J Pharmacol 2003; 139:388-98. [PMID: 12770944 PMCID: PMC1573861 DOI: 10.1038/sj.bjp.0705265] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2003] [Revised: 02/17/2003] [Accepted: 02/26/2003] [Indexed: 12/15/2022] Open
Abstract
1 Since most inflammatory mediators that stimulate granulocyte responsiveness also delay apoptosis, it is often assumed that activation and longevity are causally related. Using isolated human peripheral blood neutrophils and eosinophils, we examined this association by exploiting the proinflammatory lipid mediators, the leukotrienes (LTs), and investigated granulocyte function and apoptosis. 2 LTB(4) induced elevation of intracellular free Ca(2+) concentration ([Ca(2+)](i)), cell polarisation and retardation of neutrophil apoptosis, although the antiapoptotic effect occurred only at concentrations > or =300 nM. LTB(4)-induced activation was attenuated by CP-105,696, a BLT1-specific antagonist suggesting classical LTB(4) receptor BLT1 involvement. 3 Despite demonstrating the presence of the neutrophil intracellular LTB(4) receptor peroxisome-proliferator activator receptor-alpha (PPARalpha) in neutrophils, the selective PPARalpha agonist WY-14,643 did not mimic LTB(4)-induced prosurvival effects. 4 LTB(4)-induced survival, however, also appeared to be mediated by BLT1 since CP-105,696 inhibited the LTB(4)-mediated antiapoptotic effect. Furthermore, based on studies with CP-105,696 and 5-lipoxygenase inhibitors, lipopolysaccharide (LPS)-, granulocyte-macrophage colony-stimulating factor (GM-CSF)-, dexamethasone- and dibutyryl-cAMP (db-cAMP)-induced delay of neutrophil apoptosis did not involve autocrine production of LTB(4). 5 Although LTB(4) and LTD(4) induced human eosinophil [Ca(2+)](i) elevation and polarization, these LTs did not influence eosinophil apoptosis. Furthermore, LTB(4)- and LTD(4)-induced eosinophil activation was attenuated by CP-105,696 and the Cys-LT(1) receptor antagonist montelukast, respectively, highlighting specific receptor dependency. 6 Thus, mediator-triggered granulocyte activation and antiapoptotic pathways are distinct events that can be differentially regulated.
Collapse
|
149
|
Walch L, Norel X, Bäck M, Gascard JP, Dahlén SE, Brink C. Pharmacological evidence for a novel cysteinyl-leukotriene receptor subtype in human pulmonary artery smooth muscle. Br J Pharmacol 2002; 137:1339-45. [PMID: 12466244 PMCID: PMC1573615 DOI: 10.1038/sj.bjp.0704991] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. To characterize the cysteinyl-leukotriene receptors (CysLT receptors) in isolated human pulmonary arteries, ring preparations were contracted with leukotriene C(4) (LTC(4)) and leukotriene D(4) (LTD(4)) in either the absence or presence of the selective CysLT(1) receptor antagonists, ICI 198615, MK 571 or the dual CysLT(1)/CysLT(2) receptor antagonist, BAY u9773. 2. Since the contractions induced by the cysteinyl-leukotrienes (cysLTs) in intact preparations failed to attain a plateau response over the concentration range studied, the endothelium was removed and the tissue treated continuously with indomethacin (Rubbed+INDO). In these latter preparations, the pEC(50) for LTC(4) and LTD(4) were not significantly different (7.61+/-0.07, n=20 and 7.96+/-0.09, n=22, respectively). However, the LTC(4) and LTD(4) contractions were markedly potentiated when compared with data from intact tissues. 3. Leukotriene E(4) (LTE(4)) did not contract human isolated pulmonary arterial preparations. In addition, treatment of preparations with LTE(4) (1 microM; 30 min) did not modify either the LTC(4) or LTD(4) contractions. 4. Treatment of preparations with the S-conjugated glutathione (S-hexyl-GSH; 100 microM, 30 min), an inhibitor of the metabolism of LTC(4) to LTD(4), did not modify LTC(4) contractions. 5. The pEC(50) values for LTC(4) were significantly reduced by treatment of the preparations with either ICI 198615, MK 571 or BAY u9773 and the pK(B) values were: 7.20, 7.02 and 6.26, respectively. In contrast, these antagonists did not modify the LTD(4) pEC(50) values. 6. These findings suggest the presence of two CysLT receptors on human pulmonary arterial vascular smooth muscle. A CysLT(1) receptor with a low affinity for CysLT(1) antagonists and a novel CysLT receptor subtype, both responsible for vasoconstriction. Activation of this latter receptor by LTC(4) and LTD(4) induced a contractile response which was resistant to the selective CysLT(1) antagonists (ICI 198615 and MK 571) as well as the non-selective (CysLT(1)/CysLT(2)) antagonist, BAY u9773.
Collapse
|
150
|
Gray PA, Warner TD, Vojnovic I, Del Soldato P, Parikh A, Scadding GK, Mitchell JA. Effects of non-steroidal anti-inflammatory drugs on cyclo-oxygenase and lipoxygenase activity in whole blood from aspirin-sensitive asthmatics vs healthy donors. Br J Pharmacol 2002; 137:1031-8. [PMID: 12429575 PMCID: PMC1573571 DOI: 10.1038/sj.bjp.0704927] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Cyclo-oxygenase (COX) and lipoxygenase (LO) share a common substrate, arachidonic acid. Aspirin and related drugs inhibit COX activity. In a subset of patients with asthma aspirin induces clinical symptoms associated with increased levels of certain LO products, a phenomenon known as aspirin-sensitive asthma. The pharmacological pathways regulating such responses are not known. 2. Here COX-1 and LO activity were measured respectively by the formation of thromboxane B(2) (TXB(2)) or leukotrienes (LT) C(4), D(4) and E(4) in whole blood stimulated with A23187. COX-2 activity was measured by the formation of prostaglandin E(2) (PGE(2)) in blood stimulated with lipopolysaccharide (LPS) for 18 h. 3. No differences in the levels of COX-1, COX-2 or LO products or the potency of drugs were found in blood from aspirin sensitive vs aspirin tolerant patients. Aspirin, indomethacin and nimesulide inhibited COX-1 activity, without altering LO activity. Indomethacin, nimesulide and the COX-2 selective inhibitor DFP [5,5-dimethyl-3-(2-isopropoxy)-4-(4-methanesulfonylphenyl)-2(5H)-furanone] inhibited COX-2 activity. NO-aspirin, like aspirin inhibited COX-1 activity in blood from both groups. However, NO-aspirin also reduced LO activity in the blood from both patient groups. Sodium salicylate was an ineffective inhibitor of COX-1, COX-2 or LO activity in blood from both aspirin-sensitive and tolerant patients. 4. Thus, when COX activity in the blood of aspirin-sensitive asthmatics is blocked there is no associated increase in LO products. Moreover, NO-aspirin, unlike other NSAIDs tested, inhibited LO activity in the blood from both aspirin sensitive and aspirin tolerant individuals. This suggests that NO-aspirin may be better tolerated than aspirin by aspirin-sensitive asthmatics.
Collapse
|