Leukotriene pathway genetics and pharmacogenetics in allergy

Qijiao Shengbai Capsule alleviated leukopenia by interfering leukotriene pathway: Integrated network study of multi-omics

BACKGROUND

Leukopenia could be induced by chemotherapy, which leads to bone marrow suppression and even affects the therapeutic progression of cancer. Qijiao Shengbai Capsule (QSC) has been used for the treatment of leukopenia in clinic, but its bioactive components and mechanisms have not yet been elucidated clearly.

PURPOSE

This study aimed to elucidate the molecular mechanisms of QSC in treating leukopenia.

STUDY DESIGN

Serum pharmacochemistry, multi-omics, network pharmacology, and validation experiment were combined to study the effect of QSC in murine leukopenia model.

METHODS

First, UPLC-QTOF-MS was used to clarify the absorbed components of QSC. Then, cyclophosphamide (CTX) was used to induce mice model with leukopenia, and the therapeutic efficacy of QSC was assessed by an integrative approach of multi-omics and network pharmacology strategy. Finally, molecular mechanisms and potential therapeutic targets were identified by validated experiments.

RESULTS

121 compounds absorbed in vivo were identified. QSC significantly increase the count of white blood cells (WBCs) in peripheral blood of leukopenia mice with 15 days treatment. Multi-omics and network pharmacology revealed that leukotriene pathway and MAPK signaling pathway played crucial roles during the treatment of leukopenia with QSC. Six targets (ALOX5, LTB4R, CYSLTR1, FOS, JUN, IL-1β) and 13 prototype compounds were supposed to be the key targets and potential active components, respectively. The validation experiment further confirmed that QSC could effectively inhibit the inflammatory response induced by leukopenia. The inhibitors of ALOX5 activity can significantly increase the number of WBCs in leukopenia mice. Molecular docking of ALOX5 suggested that calycosin, daidzein, and medicarpin were the potentially active compounds of QSC.

CONCLUSION

Leukotriene pathway was found for the first time to be a key role in the development of leukopenia, and ALOX5 was conformed as the potential target. QSC may inhibit the inflammatory response and interfere the leukotriene pathway, it is able to improve hematopoiesis and achieve therapeutic effects in the mice with leukopenia.

A critical role for Macrophage-derived Cysteinyl-Leukotrienes in HIV-1 induced neuronal injury

Macrophages (MΦ) infected with human immunodeficiency virus (HIV)-1 or activated by its envelope protein gp120 exert neurotoxicity. We found previously that signaling via p38 mitogen-activated protein kinase (p38 MAPK) is essential to the neurotoxicity of HIVgp120-stimulated MΦ. However, the associated downstream pathways remained elusive. Here we show that cysteinyl-leukotrienes (CysLT) released by HIV-infected or HIVgp120 stimulated MΦ downstream of p38 MAPK critically contribute to neurotoxicity. SiRNA-mediated or pharmacological inhibition of p38 MAPK deprives MΦ of CysLT synthase (LTC4S) and, pharmacological inhibition of the cysteinyl-leukotriene receptor 1 (CYSLTR1) protects cerebrocortical neurons against toxicity of both gp120-stimulated and HIV-infected MΦ. Components of the CysLT pathway are differentially regulated in brains of HIV-infected individuals and a transgenic mouse model of NeuroHIV (HIVgp120tg). Moreover, genetic ablation of LTC4S or CysLTR1 prevents neuronal damage and impairment of spatial memory in HIVgp120tg mice. Altogether, our findings suggest a novel critical role for cysteinyl-leukotrienes in HIV-associated brain injury.

Identification of biomarkers and immune infiltration characterization of lipid metabolism-associated genes in osteoarthritis based on machine learning algorithms

Osteoarthritis (OA) is a prevalent degenerative condition commonly observed in the elderly, leading to consequential disability. Despite notable advancements made in clinical strategies for OA, its pathogenesis remains uncertain. The intricate association between OA and metabolic processes has yet to receive comprehensive exploration. In our investigation, we leveraged public databases and applied machine learning algorithms, including WGCNA, LASSO, RF, immune infiltration analysis, and pathway enrichment analysis, to scrutinize the role of lipid metabolism-associated genes (LAGs) in the OA. Our findings identified three distinct biomarkers, and evaluated their expression to assess their diagnostic value in the OA patients. The exploration of immune infiltration in these patients revealed an intricate relationship between immune cells and the identified biomarkers. In addition, in vitro experiments, including qRT-PCR, Western blot, chondrocyte lipid droplets detection and mitochondrial fatty acid oxidation measurement, further verified abnormal expressions of selected LAGs in OA cartilage and confirmed the correlation between lipid metabolism and OA.

Extrinsic and intrinsic modulators of inflammation-resolution signaling in heart failure

Chronic and uncleared inflammation is the root cause of various cardiovascular diseases. Fundamentally, acute inflammation is supportive when overlapping with safe clearance of inflammation termed resolution; however, if the lifestyle-directed extrinsic factors such as diet, sleep, exercise, or physical activity are misaligned, that results in unresolved inflammation. Although genetics play a critical role in cardiovascular health, four extrinsic risk factors-unhealthy processed diet, sleep disruption or fragmentation, sedentary lifestyle, thereby, subsequent stress-have been identified as heterogeneous and polygenic triggers of heart failure (HF), which can result in several complications with indications of chronic inflammation. Extrinsic risk factors directly impact endogenous intrinsic factors, such as using fatty acids by immune-responsive enzymes [lipoxygenases (LOXs)/cyclooxygenases (COXs)/cytochromes-P450 (CYP450)] to form resolution mediators that activate specific resolution receptors. Thus, the balance of extrinsic factors such as diet, sleep, and physical activity feed-forward the coordination of intrinsic factors such as fatty acids-enzymes-bioactive lipid receptors that modulates the immune defense, metabolic health, inflammation-resolution signaling, and cardiac health. Future research on lifestyle- and aging-associated molecular patterns is warranted in the context of intrinsic and extrinsic factors, immune fitness, inflammation-resolution signaling, and cardiac health.

Association between Sex-Related ALOX5 Gene Polymorphisms and Lung Atopy Risk

Atopy is an exaggerated IgE-mediated immune response to foreign antigens in which metabolic abnormalities of the leukotrienes (LTs) pathway play a crucial role. Recent studies have described sex as a key variable in LT biosynthesis, partly explaining why treatment with anti-LT drugs in atopic subjects leads to better control of symptoms in women. In addition, variability in LT production is often associated with single nucleotide polymorphisms (SNPs) in the arachidonate 5-lipoxygenase (ALOX5) gene, which encodes the leukotriene-synthesizing enzyme machinery, 5-lipoxygenase (5-LO). This study aimed to investigate whether two SNPs of ALOX5 are implicated in sex differences in allergic diseases in a prospective cohort of 150 age- and sex-matched atopic and healthy subjects. Rs2029253 and rs2115819 were genotyped using allele-specific RT-PCR, and serum levels of 5-LO and LTB4 were measured by ELISA. Both polymorphisms are significantly more common in women than in men, and their influences on LT production vary as a function of sex, leading to a decrease in men's and an increase in women's serum levels of 5-LO and LTB4. These data represent a new resource for understanding sex-related differences in lung inflammatory diseases, partly explaining why women are more likely to develop allergic disorders than men.

Risk of Neuropsychiatric Diseases According to the use of a Leukotriene Receptor Antagonist in Middle-Aged and Older Adults with Asthma: a Nationwide Population-Based Study Using Health Claims Data in Korea

BACKGROUND

Although a leukotriene receptor antagonist (LTRA) is an effective drug for asthma, there has been increasing concern regarding neuropsychiatric (NP) adverse reactions. However, evidence for this association is not sufficient, especially in adults.

OBJECTIVE

To investigate the association between the use of an LTRA and the risk of developing NP diseases in adults with asthma.

METHODS

We performed a nationwide, retrospective, cohort study using data from the National Health Insurance Service-Health Screening Cohort (NHIS-HEALS). We selected asthma patients with no previous use of an LTRA, and NP outcomes were defined by the registration of certain International Classification of Diseases, 10th Revision codes (F00-F59) during follow-up. We obtained the hazard ratio (HR) for NP diseases according to the use of an LTRA.

RESULTS

Overall, 61,571 asthma patients without LTRA experience were enrolled, and 12,168 of them took an LTRA during the follow-up period. In the adjusted model, the HR for newly diagnosed NP diseases showed no significant difference according to use of an LTRA (HR 1.01; 95% confidence interval 0.83-1.23; P = .952). Subgroup analysis for associations between duration of LTRA use and risk of NP disease indicated no significance for all groups (<6, 6 to <12, 12 to <24, and ≥24 months). Common NP diseases included dementia (75.4% vs 76.1%), mood disorders (12.68% vs 12.80%), and panic disorders (5.63% vs 3.53%) in LTRA users and non-LTRA users, respectively, and there was no significant difference in the prevalence of each NP disease in either group.

CONCLUSIONS

The current study showed the use or duration of LTRA exposure was not associated with the occurrence of NP diseases in Korean adult asthmatics.

Echinacea purpurea water extracts suppress the release of chemical mediators from mast cells

Histamine and leukotrienes (LTs), the chemical mediators released from mast cells, play an important role in type-I allergies such as hay fever. Echinacea purpurea (EP) has traditionally been used for herbal tea and has been reported to show biological functions. We evaluated the inhibitory activity of water extracts of EP petals, leaves, and stems against the chemical mediators released from mast cell lines. Petal and leaf extracts exhibited a significant inhibitory effect on histamine release from the stimulated cells, while the stem extract did not exert any effect. Activity of the petal extract was much stronger than that of the leaf extract. All the extracts significantly suppressed LTB4 production in the stimulated cells and displayed similar activities. The petal extract decreased Syk phosphorylation and Ca2+ influx associated with signal transduction in the stimulated cells. These results suggest that EP petal extract may have a relieving effect on allergic symptoms.

PCB52 induces hepatotoxicity in male offspring through aggravating loss of clearance capacity and activating the apoptosis: Sex-biased effects on rats

Polychlorinated biphenyls (PCBs), a kind of persistent organic pollutant, can induce hepatotoxicity in mammals. However, PCB-induced hepatotoxicity in offspring and the underlying mechanisms have been rarely studied. In the present study, Wistar rats were administered with corn oil or PCB52 (1 mg/kg body weight/day, by gavage) from gestational day 7 to postnatal day 21. In the PCB52-treated group, birth body lengths and weights were significantly decreased compared with the control group, suggesting developmental toxicity. Cytoplasmic injury in hepatocytes was observed in PCB52-treated male offspring, while no pathologic change was observed in female offspring, suggesting sex-biased hepatotoxicity. Furthermore, using an RNA-Seq method, coincided with the sexual bias, 454 differential expression genes (DEGs) were screened out in liver tissues of PCB52-treated male offspring, while 10 DEGs were screened out in female offspring. By KEGG annotation analysis, 4 in 12 significant pathways in male offspring were metabolism-related. In the present study, together with cytoplasmic injury of hepatocytes, decreased metabolic enzymes both at RNA and protein levels might aggravate loss of clearance capacity of hepatocytes and induce hepatotoxicity. Moreover, over-expressed peroxisome proliferator-activated receptor delta and mitogen-activated protein kinase 9 might activate apoptosis, which was verified by the augments of cleaved poly ADP-ribose polymerase 1 and caspase 3 in PCB52-treated male offspring. Taken together, PCB52 had developmental toxicity and induced sex-biased hepatotoxicity. The hepatotoxicity in male offspring might be attributed to the aggravated loss of clearance capacity and activation of apoptosis.

Spinacetin Suppresses the Mast Cell Activation and Passive Cutaneous Anaphylaxis in Mouse Model

We previously reported the anti-inflammatory and anti-asthmatic activities of the extract of the Inula japonica Thunb. Aiming for discovery of a novel anti-inflammatory compound, we isolated spinacetin from the extract and investigated its in vitro and in vivo anti-inflammatory effect and the related mechanism. Effect of spinacetin on the Syk signaling pathway was studied in bone marrow-derived mast cells (BMMCs), and that on the nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs) was investigated in Rat basophilic leukemia (RBL)-2H3 cells and human mast cell line (HMC-1). The in vivo anti-inflammatory activity was assessed with passive cutaneous anaphylaxis (PCA) reaction assay. Spinacetin significantly inhibited the release of histamine, and production of inflammatory mediators such as leukotriene C₄ (LTC₄) and interlukin-6 (IL-6) in IgE/Ag stimulated BMMCs. Analysis of the signaling pathways demonstrated that spinacetin inhibited activation of Syk, linker of activated T cells (LAT), phospholipase Cγ (PLCγ), cytosolic phospholipase A₂ (cPLA₂), MAPKs, Akt/NF-κB, and intracellular Ca²⁺ mobilization but with no effect on Fyn and Lyn. On the other hand, spinacetin suppressed IgE/Ag-induced activation of RBL-2H3 cells with inhibition against phosphorylation of extracellular signal regulated-protein kinase (ERK), c-Jun-NH₂-terminal kinase (JNK), p38 MAPKs, PLCγ, translocation of cPLA₂, and Akt/IκBα/NF-κB signal. However, spinacetin had no effect on PMA and A23187-induced activation of HMC-1. Furthermore, oral administration of spinacetin dose-dependently attenuated IgE/Ag-mediated PCA reaction in mouse model. Taken together, spinacetin showed the activities in preventing inflammatory processes, which might be at least partially attributed to the abolishment of Syk-dependent activation of IgE/Ag-mediated mast cells.

P2Y6 contributes to ovalbumin-induced allergic asthma by enhancing mast cell function in mice

Extracelluar nucleotides have been identified as regulatory factors in asthmatic pathogenesis by activating purinergic receptors. This research aimed to investigate the function of the purinergic receptor P2Y6 in mediating airway inflammation in allergic asthma. Wild-type (WT) and P2Y6-deficient mice were stimulated with ovalbumin (OVA) to construct asthmatic mouse models. Overexpression of P2Y6 and uridine 5'-diphosphate (UDP)-releasing were demonstrated in lung tissues in ovalbumin-induced asthmatic mice. The release of the cytokine IL-4, mast cell invasion, and the airway remodeling phenotypes were more severe following the application of UDP in asthmatic mice. However, P2Y6 deficiency reduced these asthmatic pathogeneticsymptoms markedly in a mouse model. In vitro, we found that P2Y6 in purified mast cells enhanced the functions of mast cells in the inflammatory response in the asthmatic process by triggering their capability for migration, cytokine secretion and granule release. Moreover, P2Y6 stimulated the function of mast cells through activation of the AKT signaling pathway. Our data provides evidence that P2Y6 contributes to allergic airway inflammation and remodeling by enhancing the functions of mast cells in ovalbumin-induced asthmatic mice.

Genetic and Epigenetic Components of Aspirin-Exacerbated Respiratory Disease

Aspirin-exacerbated respiratory disease (AERD) severity and its clinical phenotypes are characterized by genetic variation within pathways for arachidonic acid metabolism, inflammation, and immune responses. Epigenetic effects, including DNA methylation and histone protein modification, contribute to regulation of many genes that contribute to inflammatory states in AERD. The development of noninvasive, predictive clinical tests using data from genetic, epigenetic, pharmacogenetic, and biomarker studies will improve precision medicine efforts for AERD and asthma treatment.

Pharmacogenetic and pharmacogenomic considerations of asthma treatment

INTRODUCTION

Pharmacogenetic and pharmacogenomic approaches are already utilized in some areas, such as oncology and cardiovascular disease, for selecting appropriate patients and/or establishing treatment and dosing guidelines. This is not true in asthma although many patients have different responses to drug treatment due to genetic factors. Areas covered: Several genetic factors that affect the pharmacotherapeutic responses to asthma medications, such as β₂-AR agonists, corticosteroids, and leukotriene modifiers and could contribute to significant between-person variability in response are described. Expert opinion: An expanding number of genetic loci have been associated with therapeutic responses to asthma drugs but the individual effect of one single-nucleotide polymorphism is partial. In fact, epigenetic changes can modify genetic effects in time-, environment-, and tissue-specific manners, genes interact together in networks, and nongenetic components such as environmental exposures, gender, nutrients, and lifestyle can significantly interact with genetics to determine the response to therapy. Therefore, well-designed randomized controlled trials or observational studies are now mandatory to define if response to asthma medications in individual patients can be improved by using pharmacogenetic predictors of treatment response. Meanwhile, routine implementation of pharmacogenetics and pharmacogenomics into clinical practice remains a futuristic, far-off challenge for many clinical practices.

Nrf2 Activation by 5-lipoxygenase Metabolites in Human Umbilical Vascular Endothelial Cells

5-hydroxyeicosatetraenoic acid (5-HETE) and 5-hydroxyeicosapentaenoic acid (5-HEPE) are major metabolites produced by 5-lipoxygenase (5-LOX) from arachidonic acid (AA) and eicosapentaenoic acid (EPA). Effects of hydroxides on endothelial cells are unclear, although 5-LOX is known to increase at arteriosclerotic lesions. To investigate the effects of hydroxides on human umbilical vein endothelial cells (HUVECs), the cells were treated with 50 μM each of AA, EPA, 5-HETE, and 5-HEPE. Treatment of HUVECs with 5-HETE and 5-HEPE, rather than with AA and EPA, increased the nuclear translocation of NF-E2 related factor 2 (Nrf2) and upregulated the expression of heme oxygenase-1 and cystine/glutamate transporter regulated by Nrf2. Reactive oxygen species (ROS) generation was markedly elevated in HUVECs after treatment with 5-HETE and 5-HEPE, and the pretreatment with α-tocopherol abrogated ROS levels similar to those in the vehicle control. However, ROS generation was independent of Nrf2 activation induced by 5-HETE and 5-HEPE. 5-HETE was converted to 5-oxo-eicosatetraenoic acid (5-oxo-ETE) in HUVECs, and 5-oxo-ETE increased Nrf2 activation. These results suggest that 5-HETE works as an Nrf2 activator through the metabolite 5-oxo-ETE in HUVECs. Similarly, 5-HEPE works in the same way, because 5-HEPE is metabolized to 5-oxo-eicosapentaenoic acid through the same pathway as that for 5-HETE.

Next-generation sequencing of the human TRPV1 gene and the regulating co-players LTB4R and LTB4R2 based on a custom AmpliSeq™ panel

Background

Transient receptor potential cation channel subfamily V member 1 (TRPV1) are sensitive to heat, capsaicin, pungent chemicals and other noxious stimuli. They play important roles in the pain pathway where in concert with proinflammatory factors such as leukotrienes they mediate sensitization and hyperalgesia. TRPV1 is the target of several novel analgesics drugs under development and therefore, TRPV1 genetic variants might represent promising candidates for pharmacogenetic modulators of drug effects.

Methods

A next-generation sequencing (NGS) panel was created for the human TRPV1 gene and in addition, for the leukotriene receptors BLT1 and BLT2 recently described to modulate TRPV1 mediated sensitisation processes rendering the coding genes LTB4R and LTB4R2 important co-players in pharmacogenetic approaches involving TRPV1. The NGS workflow was based on a custom AmpliSeq^™ panel and designed for sequencing of human genes on an Ion PGM^™ Sequencer. A cohort of 80 healthy subjects of Western European descent was screened to evaluate and validate the detection of exomic sequences of the coding genes with 25 base pair exon padding.

Results

The amplicons covered approximately 97% of the target sequence. A median of 2.81 x 10⁶ reads per run was obtained. This identified approximately 140 chromosome loci where nucleotides deviated from the reference sequence GRCh37 hg19 comprising the three genes TRPV1, LTB4R and LTB4R2. Correspondence between NGS and Sanger derived nucleotide sequences was 100%.

Conclusions

Results suggested that the NGS approach based on AmpliSeq^™ libraries and Ion Personal Genome Machine (PGM) sequencing is a highly efficient mutation detection method. It is suitable for large-scale sequencing of TRPV1 and functionally related genes. The method adds a large amount of genetic information as a basis for complete analysis of TRPV1 ion channel genetics and its functional consequences.

1,6-O,O-Diacetylbritannilactone suppresses activation of mast cell and airway hyper-responsiveness

Mast cells play critical roles in allergic disorders such as atopic dermatitis and allergic asthma. The aim of this study was to investigate the anti-inflammatory and anti-asthmatic activities of 1,6-O,O-diacetylbritannilactone (OODBL) isolated from Inula japonica Thunb. (I. japonica) in a murine asthma model and bone marrow-derived mast cells (BMMCs). In an ovalbumin-induced asthma model, OODBL administration attenuated the airway hyper-responsiveness induced by aerosolized methacholine and serum IgE level in asthmatic mice. In vitro system, we found that OODBL reduced leukotriene C₄ production and degranulation through the suppression of cytosolic phospholipase A₂ phosphorylation and phospholipase Cγ-mediated Ca²⁺ influx in IgE/antigen-stimulated BMMCs. Taken together, OODBL may have therapeutic potential in the treatment of allergic diseases such as asthma.

Unveiling genomic regions that underlie differences between Afec-Assaf sheep and its parental Awassi breed

BACKGROUND

Sheep production in Israel has improved by crossing the fat-tailed local Awassi breed with the East Friesian and later, with the Booroola Merino breed, which led to the formation of the highly prolific Afec-Assaf strain. This strain differs from its parental Awassi breed in morphological traits such as tail and horn size, coat pigmentation and wool characteristics, as well as in production, reproductive and health traits. To identify major genes associated with the formation of the Afec-Assaf strain, we genotyped 41 Awassi and 141 Afec-Assaf sheep using the Illumina Ovine SNP50 BeadChip array, and analyzed the results with PLINK and EMMAX software. The detected variable genomic regions that differed between Awassi and Afec-Assaf sheep (variable genomic regions; VGR) were compared to selection signatures that were reported in 48 published genome-wide association studies in sheep. Because the Afec-Assaf strain, but not the Awassi breed, carries the Booroola mutation, association analysis of BMPR1B used as the test gene was performed to evaluate the ability of this study to identify a VGR that includes such a major gene.

RESULTS

Of the 20 detected VGR, 12 were novel to this study. A ~7-Mb VGR was identified on Ovies aries chromosome OAR6 where the Booroola mutation is located. Similar to other studies, the most significant VGR was detected on OAR10, in a region that contains candidate genes affecting horn type (RXFP2), climate adaptation (ALOX5AP), fiber diameter (KATNAl1), coat pigmentation (FRY) and genes associated with fat distribution. The VGR on OAR2 included BNC2, which is also involved in controlling coat pigmentation in sheep. Six other VGR contained genes that were shown to be involved in coat pigmentation by analyzing their mammalian orthologues. Genes associated with fat distribution in humans, including GRB14 and COBLL1, were located in additional VGR. Sequencing DNA from Awassi and Afec-Assaf individuals revealed non-synonymous mutations in some of these candidate genes.

CONCLUSIONS

Our results highlight VGR that differentiate the Awassi breed from the Afec-Assaf strain, some of which may include genes that confer an advantage to Afec-Assaf and Assaf over Awassi sheep with respect to intensive sheep production under Mediterranean conditions.

Montelukast, current indications and prospective future applications

INTRODUCTION

Montelukast is recommended for the treatment of asthma, exercise -induced bronchospasm and allergic rhinitis. Several trials demonstrated potential therapeutic effects in other respiratory conditions, and different animal-model-based studies explored potential pharmacological actions in non-respiratory conditions.

AREAS COVERED

Clinical investigations on the pharmacotherapeutic effects of montelukast, in addition to in-vivo studies on animal models of non-respiratory diseases. The data discussed in this review were mainly obtained from clinical randomized trials, real-life studies, and studies based on animal models as approve of concept. As a condition, all of the discussed articles were published in journals cited by Pubmed. Expert commentary: The current clinical data are in favor of montelukast use in the management of chronic asthma as an add-on or alternative therapy to the inhaled corticosteroids. Further clinical trials are required to confirm the effectiveness and feasibility of montelukast for the treatment of conditions other than the current clinical indications.

Cysteinyl leukotriene receptor antagonist epigenetically modulates cytokine expression and maturation of human myeloid dendritic cells

BACKGROUND

Cysteinyl leukotriene receptor antagonists are important controllers in treating asthma. Human myeloid DCs (mDCs) play critical roles in the pathogenesis of asthma. However, the effects of cysteinyl leukotriene receptor antagonist on human mDCs are unknown.

METHODS

To investigate the effects of cysteinyl leukotriene receptor antagonist on the function of human mDCs, circulating mDCs were isolated from six health subjects. Human mDCs were pretreated with montelukast and were stimulated with toll-like receptor (TLR) ligands lipopolysaccharide (LPS) or polyinosinic-polycytidylic acid (poly I:C). Tumor necrosis factor (TNF)-α and interleukin (IL)-10 were measured by ELISA. Intracellular signaling was investigated by pathway inhibitors, western blot and chromatin immunoprecipitation. Costimulatory molecules expression was investigated by flow cytometry. T cell polarization function of mDCs was investigated by measuring interferon (IFN)-γ, IL-13, IL-10 and IL-17A production by T cells using mDC/T cell coculture assay.

RESULTS

Montelukast suppressed TLR-mediated TNF-α expression via the NFκB-p65 and mitogen-activated protein kinase (MAPK)-JNK pathway, and enhanced TLR-mediated IL-10 expression via the MAPK-p38 pathway and epigenetic regulation by histone H3 acetylation. Montelukast suppressed LPS-induced CD80, CD86, CD40 and HLA-DR expression. Montelukast-treated mDCs suppressed IFN-γ and IL-13 production by T cells.

CONCLUSION

Cysteinyl leukotriene receptor antagonist alters the function of human mDCs by epigenetically modulating cytokine expression, suppressing costimulatory molecules expression and inhibiting the ability to initiate Th1/Th2 responses. The effects of cysteinyl leukotriene receptor antagonist on human mDCs can be an important mechanism in treating asthma.

Genome-wide association study of leukotriene modifier response in asthma

Heterogeneous therapeutic responses to leukotriene modifiers (LTMs) are likely due to variation in patient genetics. Although prior candidate gene studies implicated multiple pharmacogenetic loci, to date, no genome-wide association study (GWAS) of LTM response was reported. In this study, DNA and phenotypic information from two placebo-controlled trials (total N=526) of zileuton response were interrogated. Using a gene-environment (G × E) GWAS model, we evaluated 12-week change in forced expiratory volume in 1 second (ΔFEV1) following LTM treatment. The top 50 single-nucleotide polymorphism associations were replicated in an independent zileuton treatment cohort, and two additional cohorts of montelukast response. In a combined analysis (discovery+replication), rs12436663 in MRPP3 achieved genome-wide significance (P=6.28 × 10(-08)); homozygous rs12436663 carriers showed a significant reduction in mean ΔFEV1 following zileuton treatment. In addition, rs517020 in GLT1D1 was associated with worsening responses to both montelukast and zileuton (combined P=1.25 × 10(-07)). These findings implicate previously unreported loci in determining therapeutic responsiveness to LTMs.

Arresting supporters: targeting neutrophils in metastasis

It is becoming increasingly clear that leukocytes dynamically regulate cancer progression and metastasis, and among leukocytes, granulocytic cells abundantly accumulate in metastatic organs; however, their function in metastasis remains controversial. In a recent report in Nature, Wculek and Malanchi clarify the role of mature neutrophils as mediators of metastatic initiation and provide a targeted approach to prevent the pro-metastatic activity of neutrophils in breast cancer models.

Genetic variants in TNFα, TGFB1, PTGS1 and PTGS2 genes are associated with diisocyanate-induced asthma

Diisocyanates are the most common cause of occupational asthma, but risk factors are not well defined. A case-control study was conducted to investigate whether genetic variants in inflammatory response genes (TNFα, IL1α, IL1β, IL1RN, IL10, TGFB1, ADAM33, ALOX-5, PTGS1, PTGS2 and NAG-1/GDF15) are associated with increased susceptibility to diisocyanate asthma (DA). These genes were selected based on their role in asthmatic inflammatory processes and previously reported associations with asthma phenotypes. The main study population consisted of 237 Caucasian French Canadians from among a larger sample of 280 diisocyanate-exposed workers in two groups: workers with specific inhalation challenge (SIC) confirmed DA (DA(+), n = 95) and asymptomatic exposed workers (AW, n = 142). Genotyping was performed on genomic DNA, using a 5' nuclease PCR assay. After adjusting for potentially confounding variables of age, smoking status and duration of exposure, the PTGS1 rs5788 and TGFB1 rs1800469 single nucleotide polymorphisms (SNP) showed a protective effect under a dominant model (OR = 0.38; 95% CI = 0.17, 0.89 and OR = 0.38; 95% CI = 0.18, 0.74, respectively) while the TNFα rs1800629 SNP was associated with an increased risk of DA (OR = 2.08; 95% CI = 1.03, 4.17). Additionally, the PTGS2 rs20417 variant showed an association with increased risk of DA in a recessive genetic model (OR = 6.40; 95% CI = 1.06, 38.75). These results suggest that genetic variations in TNFα, TGFB1, PTGS1 and PTGS2 genes contribute to DA susceptibility.

The role of lipoxygenases in pathophysiology; new insights and future perspectives

Lipoxygenases (LOXs) are dioxygenases that catalyze the formation of corresponding hydroperoxides from polyunsaturated fatty acids such as linoleic acid and arachidonic acid. LOX enzymes are expressed in immune, epithelial, and tumor cells that display a variety of physiological functions, including inflammation, skin disorder, and tumorigenesis. In the humans and mice, six LOX isoforms have been known. 15-LOX, a prototypical enzyme originally found in reticulocytes shares the similarity of amino acid sequence as well as the biochemical property to plant LOX enzymes. 15-LOX-2, which is expressed in epithelial cells and leukocytes, has different substrate specificity in the humans and mice, therefore, the role of them in mammals has not been established. 12-LOX is an isoform expressed in epithelial cells and myeloid cells including platelets. Many mutations in this isoform are found in epithelial cancers, suggesting a potential link between 12-LOX and tumorigenesis. 12R-LOX can be found in the epithelial cells of the skin. Defects in this gene result in ichthyosis, a cutaneous disorder characterized by pathophysiologically dried skin due to abnormal loss of water from its epithelial cell layer. Similarly, eLOX-3, which is also expressed in the skin epithelial cells acting downstream 12R-LOX, is another causative factor for ichthyosis. 5-LOX is a distinct isoform playing an important role in asthma and inflammation. This isoform causes the constriction of bronchioles in response to cysteinyl leukotrienes such as LTC4, thus leading to asthma. It also induces neutrophilic inflammation by its recruitment in response to LTB4. Importantly, 5-LOX activity is strictly regulated by 5-LOX activating protein (FLAP) though the distribution of 5-LOX in the nucleus. Currently, pharmacological drugs targeting FLAP are actively developing. This review summarized these functions of LOX enzymes under pathophysiological conditions in mammals.

Determination of urinary levels of leukotriene B(4) using ad highly specific and sensitive methodology based on automatic MEPS combined with UHPLC-PDA analysis

Leukotriene B4 (LTB4) is a potent mediator of inflammation and plays a key function in the pathophysiology of chronic asthma. Detectable urinary levels of LTB4, arises from the activation of leukotriene pathways. In this study an ultra-fast, selective and sensitive analytical method based on semi-automatic microextraction by packed sorbents (MEPS) technique, using a new digitally controlled syringe (eVol®) combined with ultra-high pressure liquid chromatography (UHPLC), is proposed for the measurement of urinary LTB4 (U-LTB4) levels in a group of asthmatic patients (APs) and healthy controls (CTRL). Important parameters affecting MEPS performance, namely sorbent type, number of extraction cycles (extract-discard) and elution volume, were evaluated. The optimal experimental conditions among those investigated for the quantification of U-LTB4 in urine samples were as follows: porous graphitic carbon sorbent (PGC), 10 extractions cycle (10×250 μL of sample) and LTB4 elution with 100 μL of acetonitrile. The UHPLC optimum conditions resulted in a mobile phase consisting of 95% (v/v) of acid aqueous solution (v/v), and acetonitrile 5% (v/v); flow rate of 500 µL/min, and a column temperature of 37±0.1 °C. Under optimized conditions the proposed method exhibit good selectivity and sensitivity LOD (0.37 ng/mL) and LOQ (1.22 ng/mL). The recovery ranging from 86.4 to 101.1% for LTB4, with relative standard deviations (% RSD) no larger than 5%. In addition, the method also afforded good results in terms of linearity (r(2)>0.995) within the established concentration range, with a residual deviation for each calibration point below 6%, and intra- and inter-day repeatability in urine samples with RSD values lower than 4 and 5%, respectively. The application of the method to urine samples revealed a tendency towards the increased urinary LTB4 levels in APs (5.42±0.17 ng/mL) when compared to those of CTRL group (from ND to 1.9 ng/mL). Urinary measurement of LTB4 may be an interesting and non-invasive option to assess control of asthma.

Genome-Wide Association Study Identifies Novel Pharmacogenomic Loci For Therapeutic Response to Montelukast in Asthma

Background

Genome-wide association study (GWAS) is a powerful tool to identify novel pharmacogenetic single nucleotide polymorphisms (SNPs). Leukotriene receptor antagonists (LTRAs) are a major class of asthma medications, and genetic factors contribute to variable responses to these drugs. We used GWAS to identify novel SNPs associated with the response to the LTRA, montelukast, in asthmatics.

Methods

Using genome-wide genotype and phenotypic data available from American Lung Association - Asthma Clinical Research Center (ALA-ACRC) cohorts, we evaluated 8-week change in FEV₁ related to montelukast administration in a discovery population of 133 asthmatics. The top 200 SNPs from the discovery GWAS were then tested in 184 additional samples from two independent cohorts.

Results

Twenty-eight SNP associations from the discovery GWAS were replicated. Of these, rs6475448 achieved genome-wide significance (combined P = 1.97 x 10^-09), and subjects from all four studies who were homozygous for rs6475448 showed increased ΔFEV₁ from baseline in response to montelukast.

Conclusions

Through GWAS, we identified a novel pharmacogenomic locus related to improved montelukast response in asthmatics.

Anti-inflammatory constituents from Perovskia atriplicifolia

CONTEXT

Perovskia atriplicifolia Benth (Labiantae) has long been used as a traditional herbal medicine for anti-inflammation in Pakistan; this prompted us to isolate anti-inflammatory compounds from this plant.

OBJECTIVE

The objective of this study was to isolate and characterize the anti-inflammatory principles from Perovskia atriplicifolia.

MATERIALS AND METHODS

The CHCl3-soluble fraction of the methanol extract of the whole plant on column chromatography yielded compounds 1-6. The anti-inflammatory potential of the compounds 1-6 was evaluated by Leukotriene C4 (LTC4) Release Assay which was performed according to the established protocol. LTC4 in the supernatant of each well was measured using an ELISA kit (Cayman Chemical Co., Ann Arbor, MI).

RESULTS

The bioassay-guided phytochemical investigation of the CHCl3 soluble fraction of the methanol extract of Perovskia atriplicifolia furnished six compounds, abrotanone (1), abrotandiol (2), (+)-pinoresinol (3), (+)-syringaresinol (4), (+)-lariciresinol (5), and (+)-taxiresinol (6). The compounds (1-6) were evaluated for their inhibitory activities on LTC4 release. Among the tested compounds, (+)-taxiresinol (6) exhibited the most potent inhibition of LTC4 release with an IC50 value of 3.4 ± 0.09 µM followed by compounds 4, 5, 3, and 2 with an IC50 value ranging from 7.9 ± 0.04 to 17.2 ± 0.07 µM. Abrotanone (1) showed the lowest inhibition of LTC4 release with an IC50 value of 35.1 ± 0.05 µM (the positive control, zileuton, 0.77 ± 0.05 µM).

CONCLUSION

Compounds 1-6 were found to possess inhibitory activity and seem to have potential therapeutic effect on inflammatory diseases.

Hypersensitivity reactions to nonsteroidal anti-inflammatory drugs: from phenotyping to genotyping

PURPOSE OF REVIEW

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most frequent drugs involved in hypersensitivity drugs reactions. Both immunological and nonimmunological mechanisms can be involved. We describe the different phenotypes as well as analyze the genetic basis for NSAIDs hypersensitivity.

RECENT FINDINGS

Five major clinical entities are currently accepted in the classification of hypersensitivity reactions to NSAIDs. Three are mediated by nonspecific immunological mechanisms: NSAIDs-exacerbated respiratory disease, NSAIDs-exacerbated cutaneous disease and NSAIDs-induced urticaria/angioedema. Two are mediated by specific immunological mechanisms: single-NSAID-induced urticaria/angioedema or anaphylaxis and single-NSAID-induced delayed hypersensitivity reactions. The classification becomes more complex if we consider that in an important number of cases skin and airway involvement can occur, as well as the participation of other organs.

SUMMARY

Hypersensitivity reactions to NSAIDs are more complex than for other drugs like betalactams in terms of the number and types of reactions elicited, and mechanisms involved. As NSAIDs are the most frequent cause of drug hypersensitivity, it is feasible to gather a sufficient number of cases for undertaking pharmacogenetic studies.

Serum metabolomics study and eicosanoid analysis of childhood atopic dermatitis based on liquid chromatography-mass spectrometry

Atopic dermatitis (AD) is the most common inflammatory skin disease in children. In the study, ultra high performance liquid chromatography-mass spectrometry was used to investigate serum metabolic abnormalities of AD children. Two batch fasting sera were collected from AD children and healthy control; one of them was for nontargeted metabolomics analysis, the other for targeted eicosanoids analysis. AD children were divided into high immunoglobulin E (IgE) group and normal IgE group. On the basis of the two analysis approaches, it was found that the differential metabolites of AD, leukotriene B4, prostaglandins, conjugated bile acids, etc., were associated with inflammatory response and bile acids metabolism. Carnitines, free fatty acids, lactic acid, etc., increased in the AD group with high IgE, which revealed energy metabolism disorder. Amino acid metabolic abnormalities and increased levels of Cytochrome P450 epoxygenase metabolites were found in the AD group with normal IgE. The results provided a new perspective to understand the mechanism and find potential biomarkers of AD and may provide a new reference for personalized treatment.

Lipoxygenase Inhibitory Activity of Korean Indigenous Mushroom Extracts and Isolation of an Active Compound from Phellinus baumii

We investigated a total of 335 samples of Korean native mushroom extracts as part of our lipoxygenase (LOX) inhibitor screening program. Among the mushroom-methanolic extracts we investigated, 35 exhibited an inhibitory activity greater than 30% against LOX at a concentration of 100 µg/mL. Especially, Collybia maculata, Tylopilus neofelleus, Strobilomyces confusus, Phellinus gilvus, P. linteus, P. baumii, and Inonotus mikadoi exhibited relatively potent LOX inhibitory activities of 73.3%, 51.6%, 52.4%, 66.7%, 59.5%, 100.0%, and 85.2%, respectively. Bioassay-guided fractionation led to the isolation of inoscavin A from the methanolic extract of P. baumii, which showed the most potent activity and was identified by spectroscopic methods. Specifically, inoscavin A exhibited potent LOX inhibitory activity with an IC50 value of 6.8 µM.

Differential DNA methylation analysis of breast cancer reveals the impact of immune signaling in radiation therapy

Radiotherapy (RT) is a central treatment modality for breast cancer patients. The purpose of our study was to investigate the DNA methylation changes in tumors following RT, and to identify epigenetic markers predicting treatment outcome. Paired biopsies from patients with inoperable breast cancer were collected both before irradiation (n = 20) and after receiving 10-24 Gray (Gy) (n = 19). DNA methylation analysis was performed by using Illumina Infinium 27K arrays. Fourteen genes were selected for technical validation by pyrosequencing. Eighty-two differentially methylated genes were identified in irradiated (n = 11) versus nonirradiated (n = 19) samples (false discovery rate, FDR = 1.1%). Methylation levels in pathways belonging to the immune system were most altered after RT. Based on methylation levels before irradiation, a panel of five genes (H2AFY, CTSA, LTC4S, IL5RA and RB1) were significantly associated with clinical response (p = 0.041). Furthermore, the degree of methylation changes for 2,516 probes correlated with the given radiation dose. Within the 2,516 probes, an enrichment for pathways involved in cellular immune response, proliferation and apoptosis was identified (FDR < 5%). Here, we observed clear differences in methylation levels induced by radiation, some associated with response to treatment. Our study adds knowledge on the molecular mechanisms behind radiation response.

Variants of CEP68 gene are associated with acute urticaria/angioedema induced by multiple non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most consumed drugs worldwide because of their efficacy and utility in the treatment of pain and inflammatory diseases. However, they are also responsible for an important number of adverse effects including hypersensitivity reactions. The most important group of these reactions is triggered by non-immunological, pharmacological mechanisms catalogued under the denomination of cross-intolerance (CRI), with acute urticaria/angioedema induced by multiple NSAIDs (MNSAID-UA) the most frequently associated clinical entity. A recent genome-wide association study identified the gene encoding the centrosomal protein of 68 KDa (CEP68) as the major locus associated with aspirin intolerance susceptibility in asthmatics. In this study, we aimed to assess the role of this locus in susceptibility to CRI to NSAIDs by examining 53 common gene variants in a total of 635 patients that were classified as MNSAID-UA (n = 399), airway exacerbations (n = 110) or blended pattern (n = 126), and 425 controls. We found in the MNSAID-UA group a number of variants (17) associated (lowest p-value = 1.13×10⁻⁶), including the non-synonymous Gly74Ser variant (rs7572857) previously associated with aspirin intolerance susceptibility in asthmatics. Although not being significant in the context of multiple testing, eight of these variants were also associated with exacerbated respiratory disease or blended reactions. Our results suggest that CEP68 gene variants may play an important role in MNSAID-UA susceptibility and, despite the different regulatory mechanisms involved depending on the specific affected organ, in the development of hypersensitivity reactions to NSAIDs.

Chronic urticaria in Chinese population: a hospital-based multicenter epidemiological study

BACKGROUND

The epidemiologic profiles of chronic urticaria (CU) vary considerably among regions, and few such data are available from China.

METHODS

We performed a multicenter open questionnaire investigation about the clinical and laboratory features of CU, defined as recurrent wheals with/without angioedema lasting for ≥6 weeks, among 3027 patients.

RESULTS

Female preponderance was observed (female/male ratio, 1.46 : 1). The mean age at diagnosis was 34.7 ± 13.8 years, and the mean disease duration was 18.5 ± 46.1 months (range, 1.5-127 months). Patients were classified as having chronic spontaneous urticaria (CSU, 61.0% of patients), physical urticaria (PU, 26.2%), or other urticaria types (OU, 2.3%). Nocturnal attacks were reported by 60% of cases. The Urticaria Activity Score (UAS) in patients with CSU was 3.8 ± 1.4. The mean Dermatology Life Quality Index was 7.3 ± 3.4 (range 0-30). Induction or exacerbation of wheals with alcohol drinking was reported by 55.7% of patients. Chronic hepatitis B was less prevalent in our CU patients compared with the general Chinese population (2.7% vs 7%). Positive autologous serum skin tests (ASSTs) were observed in 66.9% of patients. Patients with positive ASST had higher UAS, greater angioedema frequencies, longer disease durations, and poorer QoL compared with patients with negative ASST (P < 0.05).

CONCLUSION

In this Chinese population, CU usually affected youth, and CSU was the most common subtype. Autoreactivity and alcohol consumption were the top two triggers for CU, whereas latent infectious and chronic inflammatory diseases were not as common as in previous reports.

Predictors of asthma control and lung function responsiveness to step 3 therapy in children with uncontrolled asthma

BACKGROUND

Predictors of improvement in asthma control and lung function to step 3 therapy in children with persistent asthma have not been identified despite reported heterogeneity in responsiveness.

OBJECTIVE

We sought to evaluate potential predictors of asthma control and lung function responsiveness to step 3 therapy.

METHODS

A post hoc analysis from the Best Add-On Giving Effective Response (BADGER) study tested the association between baseline biological, asthma control, pulmonary function, and demographic markers and responsiveness to step-up to a higher dose of inhaled corticosteroid (ICS step-up therapy) or addition of leukotriene receptor antagonist (LTRA step-up therapy) or long-acting β₂-agonist (LABA step-up therapy).

RESULTS

In multivariate analyses higher impulse oscillometry reactance area was associated (P = .048) with a differential FEV₁ response favoring LABA over ICS step-up therapy, whereas higher urinary leukotriene E₄ levels were marginally (P = .053) related to a differential FEV₁ response favoring LTRA over LABA step-up therapy. Predictors of differential responses comparing ICS with LTRA step-up therapy were not apparent, probably because of suppression of allergic markers with low-dose ICS treatment. Minimal overlap was seen across FEV₁ and asthma control day predictors, suggesting distinct mechanisms related to lung function and asthma control day responses.

CONCLUSION

Levels of impulse oscillometry reactance area indicating peripheral airway obstruction and urinary leukotriene E₄ levels indicating cysteinyl leukotriene inflammation can differentiate LABA step-up responses from responses to LTRA or ICS step-up therapy. Further studies with physiologic, genetic, and biological markers related to these phenotypes will be needed to predict individual responses to LABA step-up therapy.

New efficacy of LTRAs (montelukast sodium): it possibly prevents food-induced abdominal symptoms during oral immunotherapy

BACKGROUND

The aim of the study was to elucidate whether leukotriene receptor antagonists (LTRAs) can prevent severe allergic reactions, which occur during oral immunotherapy (OIT) in children with food allergies.

FINDINGS

Five children with food allergies [3 allergic to hen's egg (HE), 1 to wheat, and one to cow's milk (CM); aged between 7 and 12 years; median, 8.5 years] who were started on LTRAs during OIT were retrospectively selected from among 63 children undergoing OIT. In the rush phase, after the administration of the initial dose which was set in open food challenge test, the subsequent doses were increased by approximately 1.2 times of the previous dose and were administered every 2 hours, 4 times a day. The target doses of hen's egg, wheat (udon noodle), and cow's milk in the rush phase were 50 g, 200 g, and 200 ml, respectively. The ingestion of the target dose was continued at home every day for at least a year in the maintained phase.Four participants experienced intractable abdominal pain during the rush phase; therefore, the loading dose was not increased in these children. However, the administration of LTRAs prevented their symptoms, resulting in the completion of the rush phase. One participant also experienced intractable abdominal pain during the maintenance phase. After receiving LTRAs, the target dose was able to tolerated.

CONCLUSION

The findings from this retrospective study suggest that the administration of LTRAs is useful for the prevention of adverse allergic reactions such as abdominal pain during OIT.

A novel class of fungal lipoxygenases

Lipoxygenases (LOXs) are well-studied enzymes in plants and mammals. However, fungal LOXs are less studied. In this study, we have compared fungal LOX protein sequences to all known characterized LOXs. For this, a script was written using Shell commands to extract sequences from the NCBI database and to align the sequences obtained using Multiple Sequence Comparison by Log-Expectation. We constructed a phylogenetic tree with the use of Quicktree to visualize the relation of fungal LOXs towards other LOXs. These sequences were analyzed with respect to the signal sequence, C-terminal amino acid, the stereochemistry of the formed oxylipin, and the metal ion cofactor usage. This study shows fungal LOXs are divided into two groups, the Ile- and the Val-groups. The Ile-group has a conserved WRYAK sequence that appears to be characteristic for fungal LOXs and has as a C-terminal amino acid Ile. The Val-group has a highly conserved WL-L/F-AK sequence that is also found in LOXs of plant and animal origin. We found that fungal LOXs with this conserved sequence have a Val at the C-terminus in contrast to other LOXs of fungal origin. Also, these LOXs have signal sequences implying these LOXs will be expressed extracellularly. Our results show that in this group, in addition to the Gaeumannomyces graminis and the Magnaporthe salvinii LOXs, the Aspergillus fumigatus LOX uses manganese as a cofactor.

Genome-wide association study in NSAID-induced acute urticaria/angioedema in Spanish and Han Chinese populations

AIM

Acute urticaria/angioedema (AUA) induced by cross-intolerance to NSAIDs is the most frequent clinical entity in hypersensitivity reactions to drugs. In this work, we conducted a genome-wide association study in Spanish and Han Chinese patients suffering from NSAID-induced AUA.

MATERIALS & METHODS

A whole-genome scan was performed on a total of 232 cases (112 Spanish and 120 Han Chinese) with NSAID-induced AUA and 225 unrelated controls (124 Spanish and 101 Han Chinese).

RESULTS

Although no polymorphism reached genome-wide significance, we obtained suggestive associations for three clusters in the Spanish group (RIMS1, BICC1 and RAD51L 1) and one region in the Han Chinese population (ABI3BP). Five regions showed suggestive associations after meta-analysis: HLF, RAD51L1, COL24A1, GalNAc-T13 and FBXL7. A majority of these genes are related to Ca(2+), cAMP and/or P53 signaling pathways.

CONCLUSION

The associations described were different from those related to the metabolism of arachidonic acid and could provide new mechanisms underlying NSAID-induced AUA.

Genetic variation in antioxidant enzymes, cigarette smoking, and longitudinal change in lung function

Antioxidant enzymes play an important role in the defense against oxidative stress in the lung and in the pathogenesis of chronic obstructive pulmonary disease (COPD). Sequence variation in genes encoding antioxidant enzymes may alter susceptibility to COPD by affecting longitudinal change in lung function in adults. We genotyped 384 sequence variants in 56 candidate genes in 1281 African American and 1794 European American elderly adults in the Health, Aging, and Body Composition study. Single-marker associations and gene-by-smoking interactions with rate of change in FEV₁ and FEV₁/FVC were evaluated using linear mixed-effects models, stratified by race/ethnicity. In European Americans, rs17883901 in GCLC was statistically significantly associated with rate of change in FEV₁/FVC; the recessive genotype (TT) was associated with a 0.9% per year steeper decline (P = 4.50 × 10(-5)). Statistically significant gene-by-smoking interactions were observed for variants in two genes in European Americans: the minor allele of rs2297765 in mGST3 attenuated the accelerated decline in FEV₁/FVC in smokers by 0.45% per year (P = 1.13 × 10(-4)); for participants with greater baseline smoking pack-years, the minor allele of rs2073192 in IDH3B was associated with an accelerated decline in FEV₁/FVC (P = 2.10 × 10(-4)). For both genes, nominally significant interactions (P < 0.01) were observed at the gene level in African Americans (P = 0.007 and 4.60 × 10(-4), respectively). Nominally significant evidence of association was observed for variants in SOD3 and GLRX2 in multiple analyses. This study identifies two novel genes associated with longitudinal lung function phenotypes in both African and European Americans and confirms a prior finding for GCLC. These findings suggest novel mechanisms and molecular targets for future research and advance the understanding of genetic determinants of lung function and COPD risk.

Genetic variants of the arachidonic acid pathway in non-steroidal anti-inflammatory drug-induced acute urticaria

BACKGROUND

To date, genetic studies of hypersensitivity reactions to non-steroidal anti-inflammatory drugs (NSAIDs) have been carried out mainly in aspirin-induced asthma and to a lesser extent in chronic urticaria, with no studies in patients with acute urticaria (AU), the most common entity induced by these drugs.

OBJECTIVE

In this work, we analysed the association of common variants of 15 relevant genes encoding both enzymes and receptors from the arachidonic acid (AA) pathway with NSAID-induced AU.

METHODS

Patients were recruited in several Allergy Services that are integrated into the Spanish network RIRAAF, and diagnosed of AU induced by cross-intolerance (CRI) to NSAIDs. Genotyping was carried out by TaqMan allelic discrimination assays.

RESULTS

A total of 486 patients with AU induced by CRI to NSAIDs and 536 unrelated controls were included in this large Spanish case-control study. Seven variants from 31 tested in six genes were associated in a discovery study population from Malaga (0.0003 ≤ p-value ≤ 0.041). A follow-up analysis in an independent sample from Madrid replicated three of the SNPs from the ALOX15 (rs7220870), PTGDR (rs8004654) and CYSLTR1 (rs320095) genes (1.055x10(-6) ≤meta-analysis p-value ≤ 0.003).

CONCLUSIONS AND CLINICAL RELEVANCE

Genetic variants of the AA pathway may play an important role in NSAID-induced AU. These data may help understand the mechanism underlying this disease.

Integrative systems biology approaches in asthma pharmacogenomics

In order to improve therapeutic outcomes, there is a tremendous need to identify patients who are likely to respond to a given asthma treatment. Pharmacogenomic studies have explained a portion of the variability in drug response and provided an increasing list of candidate genes and SNPs. However, as phenotypic variation arises from a network of complex interactions among genetic and environmental factors, rather than individual genes or SNPs, a multidisciplinary, systems-level approach is required in order to understand the inter-relationships among these factors. Systems biology, which seeks to capture interactions between genetic factors and other variables, offers a promising approach to improved therapeutic outcomes in asthma. This aritcle will review and update progress in the pharmacogenomics of asthma and then discuss the application of systems biology approaches to asthma pharmacogenomics.

Genetic polymorphisms and associated susceptibility to asthma

As complex common diseases, asthma and allergic diseases are caused by the interaction of multiple genetic variants with a variety of environmental factors. Candidate-gene studies have examined the involvement of a very large list of genes in asthma and allergy, demonstrating a role for more than 100 loci. These studies have elucidated several themes in the biology and pathogenesis of these diseases. A small number of genes have been associated with asthma or allergy through traditional linkage analyses. The publication of the first asthma-focused genome-wide association (GWA) study in 2007 has been followed by nearly 30 reports of GWA studies targeting asthma, allergy, or associated phenotypes and quantitative traits. GWA studies have confirmed several candidate genes and have identified new, unsuspected, and occasionally uncharacterized genes as asthma susceptibility loci. Issues of results replication persist, complicating interpretation and making conclusions difficult to draw, and much of the heritability of these diseases remains undiscovered. In the coming years studies of complex diseases like asthma and allergy will probably involve the use of high-throughput next-generation sequencing, which will bring a tremendous influx of new information as well as new problems in dealing with vast datasets.

Secretion of two novel enzymes, manganese 9S-lipoxygenase and epoxy alcohol synthase, by the rice pathogen Magnaporthe salvinii

The mycelium of the rice stem pathogen, Magnaporthe salvinii, secreted linoleate 9S-lipoxygenase (9S-LOX) and epoxy alcohol synthase (EAS). The EAS rapidly transformed 9S-hydroperoxy-octadeca-10E,12Z-dienoic acid (9S-HPODE) to threo 10 (11)-epoxy-9S-hydroxy-12Z-octadecenoic acid, but other hydroperoxy FAs were poor substrates. 9S-LOX was expressed in Pichia pastoris. Recombinant 9S-LOX oxidized 18:2n-6 directly to 9S-HPODE, the end product, and also to two intermediates, 11S-hydroperoxy-9Z,12Z-octadecenoic acid (11S-HPODE; ∼5%) and 13R-hydroperoxy-9Z,11E-octadecadienoic acid (13R-HPODE; ∼1%). 11S- and 13R-HPODE were isomerized to 9S-HPODE, probably after oxidation to peroxyl radicals, β-fragmentation, and oxygen insertion at C-9. The 18:3n-3 was oxidized at C-9, C-11, and C-13, and to 9,16-dihydroxy-10E,12,14E-octadecatrienoic acid. 9S-LOX contained catalytic manganese (Mn:protein ∼0.2:1; Mn/Fe, 1:0.05), and its sequence could be aligned with 77% identity to 13R-LOX with catalytic manganese lipoxygenase (13R-MnLOX) of the Take-all fungus. The Leu350Met mutant of 9S-LOX shifted oxidation of 18:2n-6 from C-9 to C-13, and the Phe347Leu, Phe347Val, and Phe347Ala mutants of 13R-MnLOX from C-13 to C-9. In conclusion, M. salvinii secretes 9S-LOX with catalytic manganese along with a specific EAS. Alterations in the Sloane determinant of 9S-LOX and 13R-MnLOX with larger and smaller hydrophobic residues interconverted the regiospecific oxidation of 18:2n-6, presumably by altering the substrate position in relation to oxygen insertion.

Nordihydroguaiaretic acid inhibition of NFATc1 suppresses osteoclastogenesis and arthritis bone destruction in rats

Nordihydroguaiaretic acid (NDGA) is known to have prominent anticancer activity against several cancers, and is also known to be an inhibitor of 5-lipoxygenase (5-LO). In this study, we investigated the regulatory function of NDGA on inflammatory bone destruction mediated by osteoclasts. NDGA markedly inhibited receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-induced formation of osteoclasts in cultures of murine osteoclast precursor cell line RAW-D cells and primary bone marrow-derived macrophages culture systems. The inhibitory effect of NDGA on osteoclastogenesis did not arise from the inhibition of 5-LO activity. NDGA did not affect MAPKs, such as p38, JNK, and NF-κB, but significantly inhibited the induction of NFATc1, a key transcription factor for osteoclastogenesis. NDGA also suppressed activation of ERK in osteoclast precursors. RANKL-induced calcium oscillation observed in osteoclast precursors was completely diminished by the addition of NDGA. In mature osteoclasts, RANKL-induced nuclear translocation of NFATc1 was clearly inhibited by NDGA treatment. Finally, in vivo studies demonstrated that administration of NDGA significantly reduced severe bone destruction and osteoclast recruitment in the ankle joint of rats with adjuvant-induced arthritis. These results indicate the potential utility of NDGA as a therapeutic agent for ameliorating inflammatory bone destruction in rheumatoid arthritis.

Leukotriene B4 receptor locus gene characterisation and association studies in asthma

BACKGROUND

Polymorphisms spanning genes involved in the production of leukotriene B4 (LTB4) e.g. ALOX5AP and LTA4H are associated with asthma susceptibility, suggesting a role for LTB4 in disease. The contribution of LTB4receptor polymorphism is currently unknown. The aim of this study was to characterise the genes for the two pivotal LTB4 receptors, LTB4R1 and LTB4R2 in lung tissue and determine if polymorphisms spanning these genes are associated with asthma and disease severity.

METHODS

Rapid amplification of cDNA ends (RACE) was used to characterise the LTB4R1 and LTB4R2 gene structure in lung. The LTB4R1/2 locus on chromosome 14q11.2 was screened for polymorphic variation. Six LTB4R single nucleotide polymorphisms (SNPs) were genotyped in 370 Caucasian asthma families and 299 Adult Asthma Individuals (n=1877 total) and were evaluated for association with asthma and severity (BTS) outcome measures using Family Based Association Test, linear regression and chi square.

RESULTS

LTB4R1 has complex mRNA arrangement including multiple 5'-untranslated exons, suggesting additional levels of regulation. Three potential promoter regions across the LTB4R1/2 locus were identified with some airway cell specificity. 22 SNPs (MAF>0.01) were validated across the LTB4R locus in the Caucasian population. LTB4R1 and LTB4R2 SNPs were not associated with asthma susceptibility, FEV1 or severity.

CONCLUSIONS

LTB4R1 and LTB4R2 shows splice variation in the 5'-untranslated region and multiple promoter regions. The functional significance of this is yet to be determined. Both receptor genes were shown to be polymorphic. LTB4R polymorphisms do not appear to be susceptibility markers for the development of asthma in Caucasian subjects.

Association between arachidonate 5-lipoxygenase-activating protein (ALOX5AP) and lung function in a Korean population

Arachidonate 5-lipoxygenase-activating protein (ALOX5AP) plays a role in the 5-lipoxygenase (LO) pathway, which includes the LTC(4), LTD(4), LTE(4) and LTB(4). These leukotrienes are known causative factors of asthma, allergy, atopy and cardiovascular diseases. ALOX5AP lacks enzyme activity and acts by helping 5-LO function. In this study, healthy and general subjects who live in rural and urban areas of Korea were tested for the association of ALOX5AP polymorphisms with lung function. Lung function was also estimated by calculating the predicted values for forced expiratory volume in one second (FEV(1) _%PRED) and the proportion of the forced vital capacity exhaled in the first second (FEV(1) /FVC_PRED). The linear regression was adjusted for residence area, gender, age, height and smoking status. The analysis revealed associations between FEV(1) and the single-nucleotide polymorphism (SNP) rs9506352 and the haplotype TCAC (permuted P-value < 0.05). The linkage disequilibrium block that included the significant SNPs overlapped with SNPs that were revealed previously to associate with myocardial infarction and asthma and to affect lung function. This study is the first to demonstrate the association between lung function and ALOX5AP polymorphisms in a healthy and general population.