sphingosine-1-phosphate and Asthma

Sphingolipid molecules have recently attracted attention as signaling molecules in allergic inflammation diseases. Sphingosine-1-phosphate (S1P) is synthesized by two isoforms of sphingosine kinases (SPHK 1 and SPHK2) and is known to be involved in various cellular processes. S1P levels reportedly increase in allergic inflammatory diseases, such as asthma and anaphylaxis. FcεRI signaling is necessary for allergic inflammation as it can activate the SPHKs and increase the S1P level; once S1P is secreted, it can bind to the S1P receptors (S1PRs). The role of S1P signaling in various allergic diseases is discussed. Increased levels of S1P are positively associated with asthma and anaphylaxis. S1P can either induce or suppress allergic skin diseases in a context-dependent manner. The crosstalk between FcεRI and S1P/SPHK/S1PRs is discussed. The roles of the microRNAs that regulate the expression of the components of S1P signaling in allergic inflammatory diseases are also discussed. Various reports suggest the role of S1P in FcεRI-mediated mast cell (MC) activation. Thus, S1P/SPHK/S1PRs signaling can be the target for developing anti-allergy drugs.

Topics: Anaphylaxis; Asthma; Humans; Inflammation; Receptors, IgE; Sphingosine

Sphingolipids are amphiphatic molecules ubiquitously expressed in all eukaryotic cell membranes. Initially characterized as structural components of cell membranes, sphingolipids have emerged as sources of important signalling molecules over the past decade. Sphingolipid metabolites, such as ceramide and S1P (sphingosine 1-phosphate), have been demonstrated to have roles as potent bioactive messengers involved in cell differentiation, proliferation, apoptosis, migration and angiogenesis. The importance of SphK (sphingosine kinase) and S1P in inflammation has been demonstrated extensively. The prevalence of asthma is increasing in many developed nations. Consequently, there is an urgent need for the development of new agents for the treatment of asthma, especially for patients who respond poorly to conventional therapy. Recent studies have demonstrated the important role of SphK and S1P in the development of asthma by regulating pro-inflammatory responses. These novel pathways represent exciting potential therapeutic targets in the treatment of asthma and are described in the present review.

Topics: Animals; Anti-Asthmatic Agents; Asthma; Cytokines; Disease Models, Animal; Epithelial Cells; Fingolimod Hydrochloride; Humans; Inflammation; Lung; Lysophospholipids; Mast Cells; Mice; Phosphotransferases (Alcohol Group Acceptor); Propylene Glycols; Receptors, Lysosphingolipid; Signal Transduction; Sphingolipids; Sphingosine

Sphingolipids are formed via the metabolism of sphingomyelin, a constituent of the plasma membrane, or by de novo synthesis. Enzymatic pathways result in the formation of several different lipid mediators, which are known to have important roles in many cellular processes, including proliferation, apoptosis and migration. Several studies now suggest that these sphingolipid mediators, including ceramide, ceramide 1-phosphate and sphingosine 1-phosphate (S1P), are likely to have an integral role in inflammation. This can involve, for example, activation of pro-inflammatory transcription factors in different cell types and induction of cyclooxygenase-2, leading to production of pro-inflammatory prostaglandins. The mode of action of each sphingolipid is different. Increased ceramide production leads to the formation of ceramide-rich areas of the membrane, which may assemble signalling complexes, whereas S1P acts via high-affinity G-protein-coupled S1P receptors on the plasma membrane. Recent studies have demonstrated that in vitro effects of sphingolipids on inflammation can translate into in vivo models. This review will highlight the areas of research where sphingolipids are involved in inflammation and the mechanisms of action of each mediator. In addition, the therapeutic potential of drugs that alter sphingolipid actions will be examined with reference to disease states, such as asthma and inflammatory bowel disease, which involve important inflammatory components. A significant body of research now indicates that sphingolipids are intimately involved in the inflammatory process and recent studies have demonstrated that these lipids, together with associated enzymes and receptors, can provide effective drug targets for the treatment of pathological inflammation.

Topics: Animals; Asthma; Ceramides; Humans; Inflammation; Inflammatory Bowel Diseases; Lysophospholipids; Prostaglandin-Endoperoxide Synthases; Sphingolipids; Sphingosine

The bioactive lipid sphingosine-1-phosphate (S1P) fulfils manifold tasks in the immune system acting in auto- and/or paracrine fashion. This includes regulation of apoptosis, migration and proliferation. Upon its generation by sphingosine kinases from plasma membrane sphingolipids, S1P can either act as a second messenger within cells or can be released from cells to occupy a family of specific G-protein-coupled receptors (S1P1-5). This diversity is reflected by the impact of S1P on macrophage biology and function. Over the last years it became apparent that the sphingosine kinase/S1P/S1P-receptor signalling axis in macrophages might play a central role in the pathogenesis of inflammatory diseases such as atherosclerosis, asthma, rheumatoid arthritis and cancer. Here, we summarize the current knowledge of the function of S1P in macrophage biology and discuss potential implications for pathology.

Topics: Animals; Arthritis, Rheumatoid; Asthma; Atherosclerosis; Humans; Inflammation; Lysophospholipids; Macrophage Activation; Macrophages; Neoplasms; Phosphotransferases (Alcohol Group Acceptor); Receptors, G-Protein-Coupled; Receptors, Lysosphingolipid; Signal Transduction; Sphingosine

One of the major lipid biology discoveries in last decade was the broad range of physiological activities of lysophospholipids that have been attributed to the actions of lysophospholipid receptors. The most well characterized lysophospholipids are lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P). Documented cellular effects of these lipid mediators include growth-factor-like effects on cells, such as proliferation, survival, migration, adhesion, and differentiation. The mechanisms for these actions are attributed to a growing family of 7-transmembrane, G protein-coupled receptors (GPCRs). Their pathophysiological actions include immune modulation, neuropathic pain modulation, platelet aggregation, wound healing, vasopressor activity, and angiogenesis. Here we provide a brief introduction to receptor-mediated lysophospholipid signaling and physiology, and then discuss potential therapeutic roles in human diseases.

Topics: Animals; Asthma; Autoimmune Diseases; Cardiovascular Diseases; Cell Adhesion; Cell Movement; Cell Proliferation; Cell Survival; Gap Junctions; Humans; Immunologic Factors; Lysophospholipids; Neoplasms; Receptors, G-Protein-Coupled; Receptors, Lysosphingolipid; Signal Transduction; Sphingosine

Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid metabolite that plays important roles in allergic responses, including asthma and anaphylaxis, the incidence of which is rising worldwide especially in industrialized urban populations. In this review, we will discuss how S1P is formed and released, and how it acts at many cellular levels, including mast cells, the airway epithelium, airway smooth muscle and many immune cells. Since the actions of S1P on all of these cells could exacerbate allergic responses, the proteins that synthesize, release and respond to S1P offer plausible targets for a new generation of antiinflammatory therapeutics.

Topics: Anaphylaxis; Animals; Asthma; Drug Delivery Systems; Humans; Lysophospholipids; Mast Cells; Receptors, Lysosphingolipid; Respiratory Mucosa; Sphingosine

Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid metabolite involved in many cellular processes, acting not only as an extracellular ligand to its specific G protein-coupled receptors, but also as a putative intracellular messenger with yet unidentified targets. Mast cells are tissue-dwelling pivotal early effectors of allergic responses, which produce and secrete S1P that can bind to its receptors present on mast cells to influence their activation and functions. In this review, we will first discuss the current knowledge of S1P production by two isozymes of sphingosine kinase (SphK). Mechanisms of SphK activation will be discussed, with an emphasis on experimental approaches developed to study their differential activation and biological roles in the context of mast cells. The relevance of mast cells in the etiology of allergic disorders, asthma and anaphylaxis is well established. In this review, this concept will be revisited, focusing on the contribution of S1P production and secretion to the symptoms associated with dysregulated inflammatory responses. To conclude, counteracting the proinflammatory effects of S1P could be envisioned as a therapeutic strategy to treat allergic disorders, exacerbated airway inflammation, and anaphylactic reactions, and various options will be discussed, such as the development of pharmacological tools to inhibit SphKs, S1P neutralizing monoclonal antibody, and S1P receptor antagonists.

Topics: Anaphylaxis; Animals; Antibodies, Monoclonal; Asthma; Drug Delivery Systems; Humans; Hypersensitivity; Lysophospholipids; Mast Cells; Receptors, Lysosphingolipid; Sphingosine

Dysregulation of vasomotor tone, endothelial barrier function and immune cell trafficking are central to the pathology of many lung diseases, including acute lung injury, adult respiratory distress syndrome, chronic obstructive pulmonary disease and asthma. There is increasing evidence that the serum sphingolipid sphingosine 1-phosphate and its G-protein-coupled receptors are pivotal not only in the regulation of lymphocyte migration, but also in the maintenance of vascular homeostasis and the preservation of permeability barriers that separate discrete compartments in the lung.

Topics: Animals; Asthma; Capillary Permeability; Endothelium, Vascular; Fingolimod Hydrochloride; Humans; Immunosuppressive Agents; Inflammation; Lung; Lysophospholipids; Mast Cells; Muscle, Smooth, Vascular; Propylene Glycols; Receptors, Lysosphingolipid; Respiratory Mucosa; Signal Transduction; Sphingosine; T-Lymphocytes; Vasoconstriction

Asthma is a complex condition in which exposure to environmental antigens induces inflammatory reactions in the airway characterized by activation of mast cells and eosinophils. Mast cells are known to be the main effector cells in eliciting IgE-mediated allergic response. These cells secrete various substances that perpetuate inflammation and provoke airway smooth muscle (ASM) contraction. A newly recognized addition to the repertoire of FcepsilonRI-mediated signaling events is the activation of sphingosine kinase leading to the generation of the potent sphingolipid mediator, sphingosine-1-phosphate (S1P) from sphingosine. S1P secretion by the lung significantly increases after challenge with an allergen, adding this sphingolipid metabolite to the variety of mediators that are released during an allergic reaction [FASEB J. 15 (2001) 1212]. Indeed, similar to previous reports, we found that FcepsilonRI cross-linking not only increased cellular levels of S1P, it also markedly enhanced its secretion from rat basophilic leukemia RBL-2H3 cells. Moreover, S1P induced degranulation of RBL and bone marrow derived mast cells (BMMCs) cells as determined by hexosaminidase release. Treatment of BMMCs with the sphingosine kinase inhibitors, DL-threo-dihydrosphingosine and dimethylsphingosine, reduced IgE/Ag stimulated histamine release. RT-PCR analysis demonstrated that these mast cells express S1P receptors EDG-1 and EDG-5 but not EDG-3, EDG-6 or EDG-8 transcripts. Further studies are needed to determine whether IgE triggering results in transactivation of EDG-1 or EDG-5 present on mast cells and whether this is a critical event for mast cell activation.

Topics: Airway Obstruction; Animals; Asthma; Inflammation; Lung; Lysophospholipids; Mast Cells; Models, Immunological; Muscle, Smooth; Rats; Receptors, IgE; Signal Transduction; Sphingolipids; Sphingosine

It is clear that airway smooth muscle plays an important role in the hyperresponsiveness and remodelling that occur in the asthmatic airway. This is by virtue of its roles as a contractile cell, a cell that undergoes proliferation as part of the inflammatory response, a cell that actively participates in the inflammatory response via the production of cytokines and chemokines, and perhaps as a cell that undergoes migration. Now that airway smooth muscle cells cultured from asthmatic patients have been studied in vitro, it is apparent that there is an abnormality in the growth of these cells such that they grow more rapidly than cells derived from nonasthmatic patients. This raises the possibility of identifying the exact point(s) in the signal transduction pathways at which this abnormality occurs. To do this it is necessary to define precisely the mitogenic pathways that lead to proliferation in the airway smooth muscle cell, and this information is accumulating rapidly. The possibility is raised for new therapeutic targets that are aimed specifically at the airway smooth muscle, leading to an effective method for reversing or preventing the airway remodelling that accompanies chronic severe asthma.

Topics: Airway Obstruction; Asthma; Bronchi; Cell Movement; Cells, Cultured; Extracellular Matrix; Humans; Lysophospholipids; Muscle, Smooth; Receptor, PAR-2; Receptors, Thrombin; Sphingosine

Elongation of very-long-chain fatty acids protein 6 (ELOVL6), an enzyme regulating elongation of saturated and monounsaturated fatty acids with C12 to C16 to those with C18, has been recently indicated to affect various immune and inflammatory responses; however, the precise process by which ELOVL6-related lipid dysregulation affects allergic airway inflammation is unclear.. This study sought to evaluate the biological roles of ELOVL6 in allergic airway responses and investigate whether regulating lipid composition in the airways could be an alternative treatment for asthma.. Expressions of ELOVL6 and other isoforms were examined in the airways of patients who are severely asthmatic and in mouse models of asthma. Wild-type and ELOVL6-deficient (Elovl6. ELOVL6 expression was downregulated in the bronchial epithelium of patients who are severely asthmatic compared with controls. In asthmatic mice, ELOVL6 deficiency led to enhanced airway inflammation in which lymphocyte egress from lymph nodes was increased, and both type 2 and non-type 2 immune responses were upregulated. Lipidomic profiling revealed that the levels of palmitic acid, ceramides, and sphingosine-1-phosphate were higher in the lungs of ovalbumin-immunized Elovl6. This study illustrates a crucial role for ELOVL6 in controlling allergic airway inflammation via regulation of fatty acid composition and ceramide-sphingosine-1-phosphate biosynthesis and indicates that ELOVL6 may be a novel therapeutic target for asthma.

Topics: Animals; Asthma; Ceramides; Disease Models, Animal; Inflammation; Mice; Ovalbumin

The emerging role of sphingosine-1-phosphate (S1P) in regulating smooth muscle functions has led to the exploration of the possibility that this sphingolipid could represent a potential therapeutic target in asthma and other lung diseases. Several studies in animal surrogates have suggested a role for S1P-mediated signaling in the regulation of airway smooth muscle (ASM) contraction, airway hyperresponsiveness, and airway remodeling, but evidence from human studies is lacking.. We sought to compare the responsiveness of the airways to S1P in healthy and asthmatic individuals in vivo, in isolated human airways ex vivo, and in murine airways dissected from healthy and house dust mite (HDM)-sensitized animals.. Airway responsiveness was measured by spirometry during inhalation challenges and by wire myography in airways isolated from human and mouse lungs. Thymidine incorporation and calcium mobilization assays were used to study human ASM cell responses.. S1P did not induce contraction of airways isolated from healthy and HDM-exposed mice, nor in human airways. Similarly, there was no airway constriction observed in healthy and asthmatic subjects in response to increasing concentrations of inhaled S1P. However, a 30-minute exposure to S1P induced a significant concentration-dependent enhancement of airway reactivity to methacholine and to histamine in murine and human airways, respectively. HDM-sensitized mice demonstrated a significant increase in methacholine responsiveness, which was not further enhanced by S1P treatment. S1P also concentration-dependently enhanced proliferation of human ASM cells, an effect mediated through S1P receptor type 2, as shown by selective antagonism and S1P receptor type 2 small-interfering RNA knockdown.. Our data suggest that S1P released locally into the airways may be involved in the regulation of ASM hyperresponsiveness and hyperplasia, defining a novel target for future therapies.

Topics: Animals; Asthma; Cell Proliferation; Humans; Methacholine Chloride; Mice; Muscle, Smooth; Sphingosine-1-Phosphate Receptors

Airway remodelling is a critical feature of chronic lung diseases. Epithelial-mesenchymal transition (EMT) represents an important source of myofibroblasts, contributing to airway remodelling. Here, we investigated the sphingosine-1-phosphate (S1P) role in EMT and its involvement in asthma-related airway dysfunction.. A549 cells were used to assess the S1P effect on EMT and its interaction with TGF-β signalling. To assess the S1P role in vivo and its impact on lung function, two experimental models of asthma were used by exposing BALB/c mice to subcutaneous administration of either S1P or ovalbumin (OVA).. Following incubation with TGF-β or S1P, A549 acquire a fibroblast-like morphology associated with an increase of mesenchymal markers and down-regulation of the epithelial. These effects are reversed by treatment with the TGF-β receptor antagonist LY2109761. Systemic administration of S1P to BALB/c mice induces asthma-like disease characterized by mucous cell metaplasia and increased levels of TGF-β, IL-33 and FGF-2 within the lung. The bronchi harvested from S1P-treated mice display bronchial hyperresponsiveness associated with overexpression of the mesenchymal and fibrosis markers and reduction of the epithelial.The S1P-induced switch from the epithelial toward the mesenchymal pattern correlates to a significant increase of lung resistance and fibroblast activation. TGF-β blockade, in S1P-treated mice, abrogates these effects. Finally, inhibition of sphingosine kinases by SK1-II in OVA-sensitized mice, abrogates EMT, pulmonary TGF-β up-regulation, fibroblasts recruitment and airway hyperresponsiveness.. Targeting S1P/TGF-β axis may hold promise as a feasible therapeutic target to control airway dysfunction in asthma.

Topics: Airway Remodeling; Animals; Asthma; Epithelial Cells; Epithelial-Mesenchymal Transition; Lysophospholipids; Mice; Mice, Inbred BALB C; Ovalbumin; Sphingosine; Transforming Growth Factor beta; Transforming Growth Factor beta1

Asthma is associated with inflammatory dysregulation, but the underlying metabolic signatures are unclear. This study aimed to classify asthma inflammatory phenotypes based on cellular and metabolic features.. To determine cellular and metabolic profiles, we assessed inflammatory cell markers using flow cytometry, sphingolipid (SL) metabolites using LC-MS/MS, and serum cytokines using ELISA. Targeted gene polymorphisms were determined to identify genetic predispositions related to the asthma inflammatory phenotype.

Topics: Asthma; Ceramides; Chromatography, Liquid; Eosinophils; Humans; Lysophospholipids; Phenotype; Sphingosine; Tandem Mass Spectrometry

Topics: Airway Remodeling; AMP-Activated Protein Kinases; Animals; Asthma; Cell Proliferation; Cells, Cultured; Lysophospholipids; Myocytes, Smooth Muscle; Rats; Rats, Sprague-Dawley; Respiratory System; Signal Transduction; Sphingosine; Sphingosine-1-Phosphate Receptors; STAT3 Transcription Factor; Up-Regulation

Sphingosine kinase phosphorylates sphingosine to generate sphingosine 1 phosphate (S1P) following stimulation of the five plasma membrane G-protein-coupled receptors. The objective of this study is to clarify the role of S1P and its receptors (S1PRs), especially S1PR3 in airway epithelial cells.. The effects of S1P on asthma-related genes expression were examined with the human bronchial epithelial cells BEAS-2B and Calu-3 using a transcriptome analysis and siRNA of S1PRs. To clarify the role of CCL20 in the airway inflammation, BALB/c mice were immunized with ovalbumin (OVA) and subsequently challenged with an OVA-containing aerosol to induce asthma with or without intraperitoneal administration of anti-CCL20. Finally, the anti-inflammatory effect of VPC 23019, S1PR1/3 antagonist, in the OVA-induced asthma was examined.. S1P induced the expression of some asthma-related genes, such as ADRB2, PTGER4, and CCL20, in the bronchial epithelial cells. The knock-down of SIPR3 suppressed the expression of S1P-inducing CCL20. Anti-CCL20 antibody significantly attenuated the eosinophil numbers in the bronchoalveolar lavage fluid (P<0.01). Upon OVA challenge, VPC23019 exhibited substantially attenuated eosinophilic inflammation.. S1P/S1PR3 pathways have a role in release of proinflammatory cytokines from bronchial epithelial cells. Our results suggest that S1P/S1PR3 may be a possible candidate for the treatment of bronchial asthma.

Topics: Animals; Anti-Inflammatory Agents; Asthma; Bronchi; Cell Line; Chemokine CCL20; Disease Models, Animal; Eosinophilia; Epithelial Cells; Female; Gene Expression; Gene Knockdown Techniques; Humans; Lysophospholipids; Mice; Mice, Inbred BALB C; Phosphoserine; Receptors, Adrenergic, beta-2; Receptors, Lysosphingolipid; Receptors, Prostaglandin E, EP4 Subtype; Sphingosine; Sphingosine-1-Phosphate Receptors

To observe the changes of serum sphingosine-1-phosphate (S1P) level in asthmatic patients with different severity of bronchial asthma, and to explore the evaluation value of S1P on the severity of asthma.. A prospective observational study was conducted. Fifty-two patients with asthma admitted to Department of Respiratory Medicine of the First Affiliated Hospital of Jiamusi University from November 2015 to January 2017 were enrolled. According to the severity of the disease, the patients were divided into mild, moderate and severe groups. In the same period, 25 healthy subjects were served as healthy control group. All the subjects got the peripheral venous blood collection in the morning fasting, the level of serum S1P was determined by enzyme linked immunosorbent assay (ELISA), the peripheral blood eosinophil (EOS) was counted, and the pulmonary function test was performed. The correlation among the parameters was analyzed by Pearson correlation analysis. Receiver operating characteristic curve (ROC) was plotted, and the value of serum S1P on evaluating the severity of asthma was analyzed.. During asthma attack, the serum S1P level was gradually increased with the exacerbation of the disease. Serum S1P level has significant evaluative effect on the severity of asthma.

Topics: Asthma; Humans; Lysophospholipids; Prospective Studies; Respiratory Function Tests; Severity of Illness Index; Sphingosine

Topics: Animals; Asthma; Bronchial Hyperreactivity; Ceramides; Humans; Lysophospholipids; Membrane Proteins; Mice; Mice, Transgenic; Sphingolipids; Sphingosine

In this study, we used cre-lox techniques to generate mice selectively deficient in ORMDL3 in airway epithelium (

Topics: Animals; Asthma; Disease Models, Animal; Lysophospholipids; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Polymerase Chain Reaction; Respiratory Hypersensitivity; Sphingosine

Compelling evidence suggests the involvement of sphingosine-1-phosphate (S1P) in the pathogenesis of asthma. The systemic administration of S1P causes asthma like features in the mouse involving mast cells. In this study we investigated whether disodium cromoglycate (DSCG), administered as a preventative treatment as in human therapy, could affect S1P effects on airways. BALB/c mice, treated with DSCG, received subcutaneous administration of S1P. Bronchi and pulmonary tissues were collected and functional, molecular and cellular studies were performed. DSCG inhibited S1P-induced airway hyper-reactivity as well as pulmonary inflammation. DSCG decreased the recruitment of solely mast cells and B cells in the lung. IgE serum levels, prostaglandin D

Topics: Administration, Cutaneous; Animals; Asthma; B-Lymphocytes; Bronchi; Cromolyn Sodium; Female; Humans; Immunoglobulin E; Lysophospholipids; Mast Cells; Mice; Mice, Inbred BALB C; Pneumonia; Receptors, IgE; Sphingosine; T-Lymphocytes

Sphingosine-1-phosphate (S1P) is a bioactive phospholipid that acts as a signal transducer by binding to S1P receptors (S1PR) 1 to 5. The S1P/S1PRs pathway has been associated with remodeling and allergic inflammation in asthma, but the expression pattern of S1PR and its effects on non-immune cells have not been completely clarified. The aim of this study was to examine the contribution of the signaling of S1P and S1PRs expressed in airway epithelial cells (ECs) to asthma responses in mice.. Bronchial asthma was experimentally induced in BALB/c mice by ovalbumin (OVA) sensitization followed by an OVA inhalation challenge. The effects of S1PR antagonists on the development of asthma were analyzed 24 h after the OVA challenge.. Immunohistological analysis revealed S1PR1-3 expression on mouse airway ECs. Quantitative real-time polymerase chain reaction demonstrated that S1P greatly stimulated the induction of CCL3 and TIMP2 mRNA in human airway ECs, i.e., BEAS-2B cells, in a dose-dependent manner. Pretreatment with the S1PR2 antagonist JTE013 inhibited the CCL3 gene expression in BEAS-2B cells. Immunohistological analysis also showed that the expression level of CCL3 was attenuated by JTE013 in asthmatic mice. Furthermore, JTE013 as well as anti-CCL3 antibody attenuated allergic responses. Intratracheal administration of JTE013 also attenuated eosinophilic reactions in bronchoalveolar lavage fluids. S1P induced transcription factor NFκB activation, while JTE013 greatly reduced the NFκB activation.. JTE013 attenuated allergic airway reactions by regulating CCL3 production from bronchial ECs. The intratracheal administration of JTE013 may be a promising therapeutic strategy for bronchial asthma.

Topics: Animals; Anti-Asthmatic Agents; Anti-Inflammatory Agents; Asthma; Bronchi; Chemokine CCL3; Cytokines; Disease Models, Animal; Epithelial Cells; Female; Inflammation Mediators; Lysophospholipids; Mice, Inbred BALB C; NF-kappa B; Ovalbumin; Pyrazoles; Pyridines; Receptors, Lysosphingolipid; Signal Transduction; Sphingosine; Sphingosine-1-Phosphate Receptors; STAT3 Transcription Factor; Tissue Inhibitor of Metalloproteinase-2

Increased proliferation of airway smooth muscle (ASM) cells leading to hyperplasia and increased ASM mass is one of the most characteristic features of airway remodelling in asthma. A bioactive lipid, sphingosine-1-phosphate (S1P), has been suggested to affect airway remodelling by stimulation of human ASM cell proliferation.. To investigate the effect of S1P on signalling and regulation of gene expression in ASM cells from healthy and asthmatic individuals.. Airway smooth muscle cells grown from bronchial biopsies of healthy and asthmatic individuals were exposed to S1P. Gene expression was analysed using microarray, real-time PCR and Western blotting. Receptor signalling and function were determined by mRNA knockdown and intracellular calcium mobilization experiments.. S1P potently regulated the expression of more than 80 genes in human ASM cells, including several genes known to be involved in the regulation of cell proliferation and airway remodelling (HBEGF, TGFB3, TXNIP, PLAUR, SERPINE1, RGS4). S1P acting through S1P2 and S1P3 receptors activated intracellular calcium mobilization and extracellular signal-regulated and Rho-associated kinases to regulate gene expression. S1P-induced responses were not inhibited by corticosteroids and did not differ significantly between ASM cells from healthy and asthmatic individuals.. S1P induces a steroid-resistant, pro-remodelling pathway in ASM cells. Targeting S1P or its receptors could be a novel treatment strategy for inhibiting airway remodelling in asthma.

Topics: Adrenal Cortex Hormones; Airway Remodeling; Asthma; Bronchi; Calcium; Case-Control Studies; Cells, Cultured; Cluster Analysis; Drug Resistance; Extracellular Signal-Regulated MAP Kinases; Gene Expression Profiling; Gene Expression Regulation; Humans; Lysophospholipids; Myocytes, Smooth Muscle; Receptors, Lysosphingolipid; rho-Associated Kinases; Signal Transduction; Sphingosine; Sphingosine-1-Phosphate Receptors

Sphingosine-1-phosphate (S1P), which is produced by 2 sphingosine kinase (SphK) isoenzymes, SphK1 and SphK2, has been implicated in IgE-mediated mast cell responses. However, studies of allergic inflammation in isotype-specific SphK knockout mice have not clarified their contribution, and the role that S1P plays in vivo in a mast cell- and IgE-dependent murine model of allergic asthma has not yet been examined.. We used an isoenzyme-specific SphK1 inhibitor, SK1-I, to investigate the contributions of S1P and SphK1 to mast cell-dependent airway hyperresponsiveness (AHR) and airway inflammation in mice.. Allergic airway inflammation and AHR were examined in a mast cell-dependent murine model of ovalbumin (OVA)-induced asthma. C57BL/6 mice received intranasal delivery of SK1-I before sensitization and challenge with OVA or only before challenge.. SK1-I inhibited antigen-dependent activation of human and murine mast cells and suppressed activation of nuclear factor κB (NF-κB), a master transcription factor that regulates the expression of proinflammatory cytokines. SK1-I treatment of mice sensitized to OVA in the absence of adjuvant, in which mast cell-dependent allergic inflammation develops, significantly reduced OVA-induced AHR to methacholine; decreased numbers of eosinophils and levels of the cytokines IL-4, IL-5, IL-6, IL-13, IFN-γ, and TNF-α and the chemokines eotaxin and CCL2 in bronchoalveolar lavage fluid; and decreased pulmonary inflammation, as well as activation of NF-κB in the lungs.. S1P and SphK1 play important roles in mast cell-dependent, OVA-induced allergic inflammation and AHR, in part by regulating the NF-κB pathway.

Topics: Amino Alcohols; Animals; Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Cells, Cultured; Chemokine CCL2; Female; Goblet Cells; Humans; Hyperplasia; Immunoglobulin E; Inflammation; Interferon-gamma; Interleukins; Lung; Lysophospholipids; Mast Cells; Methacholine Chloride; Mice; Mice, Inbred C57BL; NF-kappa B; Ovalbumin; Phosphotransferases (Alcohol Group Acceptor); Sphingosine; Tumor Necrosis Factor-alpha

Sphingosine-1-phosphate (S1P) is an immunomodulatory lipid mediator that plays an important role in lymphocyte trafficking. Elevated levels of S1P are found in bronchoalveolar lavage (BAL) fluid of patients with asthma; however, its role in disease is not known. FTY720, a synthetic analog of S1P, has been shown to abrogate allergic inflammation and airway hyperresponsiveness following acute allergen challenge. However, its effects on asthmatic airway remodeling induced by repeated allergen exposure are unknown. Ovalbumin (OVA)-sensitized rats were challenged on days 14, 19, and 24 after sensitization. FTY720 or vehicle (PBS) therapy was administered 1 h prior to each challenge. BAL fluid and quantitative histological analysis were performed 48 h after the last challenge. FTY720 inhibited OVA-induced features of airway remodeling including increased airway smooth muscle mass and bronchial neovascularization, without affecting lymphocyte numbers in secondary lymphoid organs. Furthermore, CD3+ cells adjacent to airway smooth muscle bundles were increased in OVA-challenged rats but the increase was inhibited by FTY720. There was an expansion of bronchus-associated lymphoid tissue following FTY720 treatment of OVA-challenged animals. Real-time quantitative PCR revealed that Th2-associated transcription factors were inhibited following FTY720 therapy. Airway remodeling is a cardinal feature of severe asthma. These results demonstrate that allergen-driven airway remodeling can be inhibited by FTY720, offering potential new therapies for the treatment of severe asthma.

Topics: Airway Remodeling; Allergens; Animals; Anti-Asthmatic Agents; Asthma; Bronchi; Bronchoalveolar Lavage Fluid; CD3 Complex; Fingolimod Hydrochloride; Immunosuppressive Agents; Lysophospholipids; Male; Muscle, Smooth; Propylene Glycols; Rats; Severity of Illness Index; Sphingosine; Treatment Outcome

The correlation between inflammatory cells and airway smooth muscle plays fundamental roles in the pathophysiology of asthma. This study was designed to determine whether pre-exposure of airway smooth muscle to sphingosine-1-phosphate (S1P), which is released from mast cells by allergic reactions, causes a deterioration of β-adrenoceptor function.. Isometric tension and the ratio of fluorescence intensities at 340 and 380 nm (F(340)/F(380)), an indicator of intracellular Ca2+ levels, were simultaneously measured using fura-2 loaded guinea-pig tracheal tissues. Intracellular cAMP levels were also measured.. Pre-exposure to S1P caused a reduction in the inhibitory effects of 0.3μM isoprenaline, a β-adrenoceptor agonist, and 10μM forskolin, a direct activator of adenylyl cyclase, against 1μM methacholine-induced contraction in concentration- and time- dependent manners. In contrast, the values of F(340)/F(380) were not augmented under this experimental condition. After incubation with S1P in the presence of 0.001-1μM Y-27632, a Rho-kinase inhibitor, the reduced responsiveness to forskolin induced by S1P was reversed in a concentration-dependent manner. Moreover, pre-treatment with pertussis toxin (PTX), an inhibitor of G(i), suppressed the loss of forskolin-induced relaxation induced by S1P. Pre-exposure to S1P markedly inhibited the augmentation of cAMP accumulation induced by forskolin. However, addition of Y-27632 and pre-exposure to PTX returned forsokin-induced cAMP accumulation to the control level.. Pre-exposure to S1P causes heterologus desensitization of β-adrenoceptors by increasing the sensitivity of airway smooth muscle to intracellular Ca2+. Ca2+ sensitization regulated by G(i) and Rho-kinase is involved in this phenomenon.

Topics: Adrenergic beta-Agonists; Amides; Animals; Asthma; Calcium Signaling; Cells, Cultured; Guinea Pigs; Humans; Isoproterenol; Lysophospholipids; Myocytes, Smooth Muscle; Pertussis Toxin; Pyridines; Receptors, Adrenergic, beta; rho-Associated Kinases; Sphingosine; Trachea

There is a need to better understand the mechanism of airway hyper-reactivity, a key feature of asthma. Evidence suggests that sphingosine-1-phosphate (S1P) could be a major player in this phenomenon. The purpose of this work was to define the S1P receptor responsible for this phenomenon. We have studied, in the rat, the effect of two S1P synthetic receptor ligands, 2-amino-2-[2-(4-octylphenyl)ethyl]propane-1,3-diol (FTY720) (which in its phosphorylated form is a potent agonist at each S1P receptor except S1P(2)) and 3-[[2-[4-phenyl-3-(trifluoromethyl)phenyl]-1-benzothiophen-5-yl]methylamino]propanoic acid (AUY954) (a selective S1P(1) agonist) on lung function in vivo. This was complemented by in vitro studies using isolated trachea from the rat, the S1P(3) receptor-deficient mouse, and its wild-type counterpart. After oral administration, FTY720 induced a generalized airway hyper-reactivity to a range of contractile stimuli. This was observed as early as 1 h postdosing, lasted for at least 24 h, and was not subject to desensitization. In both rat and wild-type mouse isolated trachea, preincubation with the active phosphorylated metabolite of FTY720 induced hyper-responsiveness to 5-hydroxytryptamine. This effect was not seen in the isolated tracheas from S1P(3) receptor-deficient mice. AUY954, did not mimic the effect of FTY720 either in vivo or in vitro. Our data are consistent with activation of the S1P pathway inducing a generalized airway hyper-reactivity in rats and mice that is mediated by the S1P(3) receptor. S1P(3) receptor antagonists might prove to be useful as new therapeutic strategies aimed at blocking the airway hyper-reactivity observed in asthma.

Topics: Albuterol; Animals; Asthma; beta-Alanine; Bronchial Hyperreactivity; Bronchoconstriction; Fingolimod Hydrochloride; Lung; Lysophospholipids; Male; Mice; Mice, Inbred C57BL; Propylene Glycols; Rats; Rats, Inbred BN; Receptors, Lysosphingolipid; Sphingosine; Sphingosine-1-Phosphate Receptors; Tachyphylaxis; Thiophenes; Trachea

To determine whether or not sphingosine-1-phosphate (S1P) is involved in the augmented bronchial smooth muscle (BSM) contractility, one of the causes of airway hyperresponsiveness in asthmatics, the effects of S1P on BSM tone were investigated in control and repeatedly antigen-challenged mice. Both in the control and antigen-challenged animals, S1P had no effect on basal tone of the isolated BSM tissues. However, in the BSMs pre-depolarized by 60mM K(+), S1P caused a significant increase in tension in the control mice. The S1P-mediated contraction was abolished by JTE-013, a selective S1P receptor 2 (S1PR2) antagonist, but not by W123, a selective S1PR1 antagonist, and BML-241, a selective S1PR3 antagonist. The S1P-mediated contraction observed in BSMs of the control mice was also inhibited by Y-27632, a Rho-kinase inhibitor, suggesting that the contraction is mediated via activations of S1PR2 and probably its downstream Rho-kinase. On the other hand, interestingly, the S1P-mediated contraction was not observed at all in BSMs of the repeatedly antigen-challenged mice. A marked and significant downregulation of mRNA for S1PR2 was also observed in BSM tissues of the diseased animals. In conclusion, S1P could augment the BSM contraction via activations of its JTE-013-sensitive receptor, probably S1PR2, and the RhoA/Rho-kinase signaling in normal mice. In BSMs of the repeatedly antigen-challenged mice, the expression level of S1PR2 was much decreased, resulting in a loss of the S1P-mediated contraction.

Topics: Animals; Asthma; Bronchi; Down-Regulation; Lysophospholipids; Male; Mice; Mice, Inbred BALB C; Muscle Contraction; Muscle, Smooth; Pyrazoles; Pyridines; Receptors, Lysosphingolipid; rho-Associated Kinases; RNA, Messenger; Sphingosine; Sphingosine-1-Phosphate Receptors; Thiazolidines

To determine if endogenously generated sphingosine-1-phosphate (S1P) is involved in the development of allergic bronchial asthma, the effects of systemic treatments with SKI-II, a specific inhibitor of sphingosine kinase, on antigen-induced bronchial smooth muscle (BSM) hyperresponsiveness and airway inflammation were examined in mice. Male BALB/c mice were actively sensitized with ovalbumin (OA) antigen and were repeatedly challenged with aerosolized antigen. Animals also received intraperitoneal injections with SKI-II (50 mg/kg) 1 h prior to each antigen challenge. The acetylcholine (ACh)-induced contraction of BSM isolated from the repeatedly antigen-challenged mice was significantly augmented, that is, BSM hyperresponsiveness, as compared with that from the control animals (P < 0.05). The BSM hyperresponsiveness induced by antigen exposure was ameliorated by the systemic treatment with SKI-II, whereas the treatments had no effect on BSM responsiveness to ACh in control animals. On the other hand, the systemic treatments with SKI-II had no effect on antigen-induced inflammatory signs, such as increase in cell counts in bronchoalveolar lavage fluids (BALFs) and change in airway histology; upregulation of BALF cytokines, such as interleukin-4 (IL-4) and IL-13; and elevation of total and OA-specific immunoglobulin E (IgE) in sera. These findings suggest that sphingosine kinase inhibitors such as SKI-II have an ability to prevent the development of BSM hyperresponsiveness, but not of allergic airway inflammation. The endogenously generated S1P might be one of the exacerbating factors for the airway hyperresponsiveness, one of the characteristic features of allergic bronchial asthma.

Topics: Animals; Antigens; Asthma; Bronchi; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Immunoglobulin E; Interleukin-13; Interleukin-4; Lysophospholipids; Male; Mice; Mice, Inbred BALB C; Muscle, Smooth; Phosphotransferases (Alcohol Group Acceptor); Sphingosine; Thiazoles

Sphingosine 1-phosphate (S1P) produced by sphingosine kinase (SPHK) is implicated in acute immunoresponses, however, mechanisms of SPHK/S1P signaling in the pathogenesis of bronchial asthma are poorly understood. In this study, we hypothesized that SPHK inhibition could ameliorate lung inflammation in ovalbumin (OVA)-challenged mouse lungs. Six- to eight-week-old C57BL/6J mice were sensitized and exposed to OVA for 3 consecutive days. Twenty-four hours later, mice lungs and bronchoalveolar lavage (BAL) fluid were analyzed. For an inhibitory effect, either of the two different SPHK inhibitors, N,N-dimethylsphingosine (DMS) or SPHK inhibitor [SK-I; 2-(p-hydroxyanilino)-4-(p-chlorophenyl) thiazole], was nebulized for 30 min before OVA inhalation. OVA inhalation caused S1P release into BAL fluid and high expression of SPHK1 around bronchial epithelial walls and inflammatory areas. DMS or SK-I inhalation resulted in a decrease in S1P amounts in BAL fluid to basal levels, accompanied by decreased eosinophil infiltration and peroxidase activity. The extent of inhibition caused by DMS inhalation was higher than that caused by SK-I. Like T helper 2 (Th2) cytokine release, OVA inhalation-induced increase in eotaxin expression was significantly suppressed by DMS pretreatment both at protein level in BAL fluid and at mRNA level in lung homogenates. Moreover, bronchial hyperresponsiveness to inhaled methacholine and goblet cell hyperplasia were improved by SPHK inhibitors. These data suggest that the inhibition of SPHK affected acute eosinophilic inflammation induced in antigen-challenged mouse model and that targeting SPHK may provide a novel therapeutic tool to treat bronchial asthma.

Topics: Administration, Inhalation; Aniline Compounds; Animals; Asthma; Bronchoalveolar Lavage Fluid; Cells, Cultured; Chemokines, CC; Disease Models, Animal; Enzyme Inhibitors; Goblet Cells; Humans; Hyperplasia; Interleukins; Lysophospholipids; Mice; Mice, Inbred C57BL; Ovalbumin; Phosphotransferases (Alcohol Group Acceptor); Respiratory Mucosa; Sphingosine; Thiazoles

Cytosolic phospholipase A(2)alpha (cPLA(2)alpha) activation is a regulatory step in the control of arachidonic acid (AA) liberation for eicosanoid formation. Sphingosine 1-phosphate (S1P) is a bioactive lipid mediator involved in the regulation of many important proinflammatory processes and has been found in the airways of asthmatic subjects. We investigated the mechanism of S1P-induced AA release and determined the involvement of cPLA(2)alpha in these events in A549 human lung epithelial cells. S1P induced AA release rapidly within 5 min in a dose- and time-dependent manner. S1P-induced AA release was inhibited by the cPLA(2)alpha inhibitors methyl arachidonyl fluorophosphonate (MAFP) and pyrrolidine derivative, by small interfering RNA-mediated downregulation of cPLA(2)alpha, and by inhibition of S1P-induced calcium flux, suggesting a significant role of cPLA(2)alpha in S1P-mediated AA release. Knockdown of the S1P3 receptor, the major S1P receptor expressed on A549 cells, inhibited S1P-induced calcium flux and AA release. The S1P-induced calcium flux and AA release was associated with sphingosine kinase 1 (Sphk1) expression and activity. Furthermore, Rho-associated kinase, downstream of S1P3, was crucial for S1P-induced cPLA(2)alpha activation. Our data suggest that S1P acting through S1P3, calcium flux, and Rho kinase activates cPLA(2)alpha and releases AA in lung epithelial cells. An understanding of S1P-induced cPLA(2)alpha activation mechanisms in epithelial cells may provide potential targets to control inflammatory processes in the lung.

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Asthma; Calcium; Calcium Signaling; Cell Line; Eicosanoids; Enzyme Activation; Enzyme Inhibitors; Gene Expression Regulation, Enzymologic; Group IV Phospholipases A2; Humans; Lung; Lysophospholipids; Organophosphonates; Phosphotransferases (Alcohol Group Acceptor); Receptors, Lysosphingolipid; Respiratory Mucosa; rho-Associated Kinases; RNA, Small Interfering; Sphingosine

Airway DCs play a crucial role in the pathogenesis of allergic asthma, and interfering with their function could constitute a novel form of therapy. The sphingosine 1-phosphate receptor agonist FTY720 is an oral immunosuppressant that retains lymphocytes in lymph nodes and spleen, thus preventing lymphocyte migration to inflammatory sites. The accompanying lymphopenia could be a serious side effect that would preclude the use of FTY720 as an antiasthmatic drug. Here we show in a murine asthma model that local application of FTY720 via inhalation prior to or during ongoing allergen challenge suppresses Th2-dependent eosinophilic airway inflammation and bronchial hyperresponsiveness without causing lymphopenia and T cell retention in the lymph nodes. Effectiveness of local treatment was achieved by inhibition of the migration of lung DCs to the mediastinal lymph nodes, which in turn inhibited the formation of allergen-specific Th2 cells in lymph nodes. Also, FTY720-treated DCs were intrinsically less potent in activating naive and effector Th2 cells due to a reduced capacity to form stable interactions with T cells and thus to form an immunological synapse. These data support the concept that targeting the function of airway DCs with locally acting drugs is a powerful new strategy in the treatment of asthma.

Topics: Administration, Inhalation; Allergens; Animals; Asthma; Cell Differentiation; Cell Movement; Cell Polarity; Dendritic Cells; Disease Models, Animal; Fingolimod Hydrochloride; Gene Expression Regulation; Heart; Lymph Nodes; Lymphocytes; Lysophospholipids; Mice; Propylene Glycols; Receptors, Lysosphingolipid; Sphingosine

Topics: Asthma; Bronchi; Bronchial Provocation Tests; Bronchoalveolar Lavage Fluid; Cells, Cultured; Chemokine CCL5; Humans; Interleukin-6; Lysophospholipids; Models, Biological; Muscle, Smooth; Signal Transduction; Sphingosine; Tumor Necrosis Factor-alpha