Sphingosine-1-phosphate induces pro-remodelling response in airway smooth muscle cells.

BACKGROUND: 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. OBJECTIVE: To investigate the effect of S1P on signalling and regulation of gene expression in ASM cells from healthy and asthmatic individuals. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Cooperative and redundant signaling of leukotriene B4 and leukotriene D4 in human monocytes.

BACKGROUND: Leukotriene B(4) (LTB(4)) and cysteinyl leukotrienes (cysLTs) are important immune mediators, often found concomitantly at sites of inflammation. Although some of the leukotriene-mediated actions are distinctive (e.g., bronchial constriction for cysLTs), many activities such as leukocyte recruitment to tissues and amplification of inflammatory responses are shared by both classes of leukotrienes. OBJECTIVE: We used human monocytes to characterize leukotriene-specific signaling, gene expression signatures, and functions and to identify interactions between LTB(4)- and cysLTs-induced pathways. METHODS: Responsiveness to leukotrienes was assessed using oligonucleotide microarrays, real-time PCR, calcium mobilization, kinase activation, and chemotaxis assays. RESULTS: Human monocytes were found to express mRNA for high- and low-affinity LTB(4) receptors, BLT(1) and BLT(2), but signal predominantly through BLT(1) in response to LTB(4) stimulation as shown using selective agonists, inhibitors, and gene knock down experiments. LTB(4) acting through BLT(1) coupled to G-protein α inhibitory subunit activated calcium signaling, p44/42 mitogen-activated protein kinase, gene expression, and chemotaxis. Twenty-seven genes, including immediate early genes (IEG), transcription factors, cytokines, and membrane receptors were significantly up-regulated by LTB(4). LTB(4) and LTD(4) had similar effects on signaling, gene expression, and chemotaxis indicating redundant cell activation pathways but costimulation with both lipid mediators was additive for many monocyte functions. CONCLUSION: Leukotriene B(4) and LTD(4) display both redundant and cooperative effects on intracellular signaling, gene expression, and chemotaxis in human monocytes. These findings suggest that therapies targeting either leukotriene alone may be less effective than approaches directed at both.

Beta2-ADR haplotypes/polymorphisms associate with bronchodilator response and total IgE in grass allergy.

Association and linkage studies of beta2-adrenergic receptor (beta2-ADR) polymorphisms in relation to the expression of asthmatic phenotypes and immune regulatory mechanisms have shown inconsistent results. In order to analyse the relevance of particular combinations of single nucleotide polymorphisms (SNPs) or haplotypes of beta2-ADR gene to bronchial asthma, bronchodilator response and total immunoglobulin E (IgE) we determined by direct DNA sequencing five SNPs (in positions: -47, -20, 46, 79, 252) in a group of 180 Caucasian subjects (110 patients with grass allergy and 70 nonatopic controls). The eight different beta2-ADR haplotypes were identified, with three the most common of them representing 92% of the studied cohort. Significantly higher (pcor = 0.0045) bronchodilator response was observed in patients with homozygotic genotype 46A/A in comparison with respective homo- and hetero-zygotes. There was no significant difference in bronchodilator response when beta2-ADR haplotypes were analysed. Significantly higher (pcor = 0.0005) total IgE levels were found in patients with beta2-ADR haplotype -47T/-20T/46A/79C/252G and homozygotic carriers of 46A (pcor = 0.0015) and 79C (pcor = 0.003) genotypes. No significant associations were found in regards to asthmatic phenotype and atopy. These results indicate that depending on phenotype studied, either an individual beta2-ADR SNP or beta2-ADR haplotype might affect disease manifestation.

Association of asthma and total IgE levels with human leucocyte antigen-DR in patients with grass allergy.

Exposure to grass pollens during the pollen season, reveals in sensitive patients symptoms of allergic rhinitis, conjunctivitis and/or bronchial asthma. It is not well understood why, in some patients, only symptoms of rhinitis occur while in others similar exposure causes symptoms of asthma and rhinitis. An association study is reported here, where the possible contribution of human leucocyte antigen (HLA)-DR gene polymorphisms to differential phenotypic expression of symptoms in patients with grass-pollen allergy was determined. HLA-DR genotyping was performed by the polymerase chain reaction with the sequence-specific primers method in 82 patients with symptoms of seasonal allergic rhinitis and/or bronchial asthma and 52 healthy nonatopic control subjects. A significant association was found between HLA-DRB1*02, B5* haplotype and asthma phenotype in patients with grass-pollen allergy when compared to patients with rhinitis only. Significantly higher total serum immunoglobulin E levels were observed in patients with HLA-DRB1*01 alleles in comparison to patients without these alleles. The data in this study suggest that human leucocyte antigen-DR locus, or other genes in linkage disequilibrium, may play an important role in asthma phenotype expression in patients with grass-pollen allergy as well as in determining total immunoglobulin E levels in these patients.

[Genetic polymorphism of beta 2-adrenoreceptor and its role in pathologic states]. / Polimorfizm genetyczny receptora beta 2-adrenergicznego i jego znaczenie w patologii.

A few polymorphic loci have recently been identified in the beta 2-adrenoceptor gene that significantly influence receptor expression and its functions. Gene structure, regulation of the receptor expression and functions in regards to genetic polymorphisms and pathology are described.

Diagnosis of pyrazolone drug sensitivity: clinical history versus skin testing and in vitro testing.

Pyrazolone drug hypersensitivity (PDH) may manifest as angioedema, urticaria, and/or life threatening anaphylactic shock. Although it has been suggested that PDH is an immunologic, probably IgE-mediated reaction, the diagnosis of PDH is still based on clinical history because there is no reliable in vitro diagnostic method currently used in clinical practice. The goal of this study was to evaluate the reliability of various methods to confirm a diagnosis of PDH. Twenty-eight patients with prior history of 71 reactions to pyrazolone drugs were studied. In all patients, pyrazolone drugs induced urticaria and angioedema. In addition, laryngeal edema occurred in 14 patients and anaphylactic shock with loss of consciousness in five patients. Skin prick test and intradermal tests using increasing concentrations of noraminophenazone were performed in 25 patients. Sera of all 28 patients were negative for pyrazolone-specific IgE as determined by an immunoenzymatic method. Peripheral blood mononuclear cells proliferative responses to pyrazolone were studied by a lymphocyte proliferation test with 3H-thymidine incorporation. Incubation of peripheral blood mononuclear cells with increasing concentrations of noraminophenazone did not induce any significant proliferation responses. Our study demonstrated that 1) intradermal skin tests correlate poorly with the clinical history of hypersensitivity reaction; and 2) in vitro tests are not useful in establishing a diagnosis of PDH.

[CYP2D6 gene polymorphism in psychiatric patients resistant to standard pharmacotherapy]. / Polimorfizm genu CYP2D6 u pacjentów chorych psychicznie opornych na klasyczna farmakoterapie.

The debrisoquine polymorphism is a genetic variation in oxidative drug metabolism mediated by CYP2D6 gene, characterized by two phenotypes, the extensive metabolizer (EM) and poor metabolizer (PM). PM phenotype is inherited as autosomal recessive trait and occurs in 5-10% of Caucasian population. It is associated with the inefficient metabolism of over 30 drugs, including many psychotropic drugs. Clinical studies shown that PM are at higher risk than EM of adverse reactions to these drugs. We genotyped 22 psychiatric patients in whom standard pharmacotherapy had failed or drug adverse events occurred and in 14 patients in whom standard therapy was successful. CYP2D6 polymorphic alleles were identified using allele specific nested PCR reaction. The PM genotype was found in 4 of 22 (18%) patients resistant to standard pharmacotherapy and in none of 14 patients with improvement after standard therapy. Unsuccessful standard psychotropic drugs therapy in psychiatric patients may be associated with PM phenotype.

Association of pyrazolone drug hypersensitivity with HLA-DQ and DR antigens.

BACKGROUND: In sensitive patients pyrazolone drugs can precipitate adverse reactions ranging from urticaria and angioedema to anaphylactic shock, presumably by immunological, IgE-mediated mechanism. However, up to now no genetic factors influencing the development of allergic reaction have been reported in this type of hypersensitivity. OBJECTIVE: The aim of our study was the investigation whether the susceptibility to development of pyrazolone drugs hypersensitivity (PDH) reactions was associated with HLA class II antigens. METHODS: To test this hypothesis we studied the distribution of HLA-DR and DQ antigens in 26 pyrazolone sensitive patients and control groups including unselected general population and clearly defined atopic and non-atopic groups. RESULTS: Significantly higher frequencies of DQ 7 and DR11 antigens were found in PDH group as compared with control unselected population (RR= 16.48, P < 0.0001; P(cor)< 0.002 and RR = 4.57, P = 0.0002; Pcor = 0.003 for DQ and DR antigen respectively). Similarly, statistically significant increased frequencies of DQ 7 and DR11 in patients with PDH were observed compared with atopic control group (RR= 18.43, P < 0.0001; Pcor <0.002 and RR= 6.33, P= 0.0007; Pcor =0.01, for DQ and DR antigen respectively). However, in comparison to non-atopic control group only the frequency of DQ 7 antigen was significantly increased (RR = 15.42, P = 0.0001; Pcor = 0.0015). DQ 7 antigen was present in 46.1% of PDH patients compared with 4.9%, 4.4% and 5.3% in the general population, atopic and non-atopic groups respectively, suggesting pyrazolone hypersensitivity as a trait positively correlated with this HLA antigen. CONCLUSION: Our data suggest a genetic predisposition to pyrazolone hypersensitivity reactions, linked to HLA-DQ locus.

Comparison of serological and molecular (PCR-SSP) techniques of HLA-DR typing in clinical laboratory routine.

Advances in molecular biology techniques allowed for introduction of PCR-based methods for HLA typing. In routine HLA typing for organ transplantation serological method is still being used as a standard, although molecular techniques are applied more and more often. The aim of our study was to compare HLA-DR typing using traditional serological method and PCR-SSP methodology in routine clinical laboratory. HLA-DR typing was performed using standard microcytotoxicity assay and PCR-SSP method in 28 patients referred to our Transplantation Immunology Unit for HLA typing. Comparison of results obtained by both methods revealed no discrepancies in 5 patients, in 12 patients the PCR-SSP typing showed additional DR antigens or splits of antigens. In 11 patients serological typing turned out to be impossible because of technical problems. Molecular PCR typing allowed for precise antigen determination in all the patients. Comparing both methods we found PCR-SSP HLA typing method very useful in routine HLA-DR determination, especially valuable in patients, in whom some problems in serological testing are expected.