High capacity for leukotriene biosynthesis in peripheral blood during pregnancy

Identification of 2,4-Dinitro-Biphenyl-Based Compounds as MAPEG Inhibitors

We identified 2,4-dinitro-biphenyl-based compounds as new inhibitors of leukotriene C₄ synthase (LTC₄ S) and 5-lipoxygenase-activating protein (FLAP), both members of the "Membrane Associated Proteins in Eicosanoid and Glutathione metabolism" (MAPEG) family involved in the biosynthesis of pro-inflammatory eicosanoids. By molecular docking we evaluated the putative binding against the targets of interest, and by applying cell-free and cell-based assays we assessed the inhibition of LTC₄ S and FLAP by the small molecules at low micromolar concentrations. The present results integrate the previously observed inhibitory profile of the tested compounds against another MAPEG member, i. e., microsomal prostaglandin E₂ synthase (mPGES)-1, suggesting that the 2,4-dinitro-biphenyl scaffold is a suitable molecular platform for a multitargeting approach to modulate pro-inflammatory mediators in inflammation and cancer treatment.

Pharmacological Validation for the Folklore Use of Ipomoea nil against Asthma: In Vivo and In Vitro Evaluation

Oxidative stress is the key factor that strengthens free radical generation which stimulates lung inflammation. The aim was to explore antioxidant, bronchodilatory along with anti-asthmatic potential of folkloric plants and the aqueous methanolic crude extract of Ipomoea nil (In.Cr) seeds which may demonstrate as more potent, economically affordable, having an improved antioxidant profile and providing evidence as exclusive therapeutic agents in respiratory pharmacology. In vitro antioxidant temperament was executed by DPPH, TFC, TPC and HPLC in addition to enzyme inhibition (cholinesterase) analysis; a bronchodilator assay on rabbit’s trachea as well as in vivo OVA-induced allergic asthmatic activity was performed on mice. In vitro analysis of 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH) expressed as % inhibition 86.28 ± 0.25 with IC50 17.22 ± 0.56 mol/L, TPC 115.5 ± 1.02 mg GAE/g of dry sample, TFC 50.44 ± 1.06 mg QE/g dry weight of sample, inhibition in cholinesterase levels for acetyl and butyryl with IC50 (0.60 ± 0.67 and 1.5 ± 0.04 mol/L) in comparison with standard 0.06 ± 0.002 and 0.30 ± 0.003, respectively, while HPLC characterization of In.Cr confirmed the existence with identification as well as quantification of various polyphenolics and flavonoids i.e., gallic acid, vanillic acid, chlorogenic acid, quercetin, kaempferol and others. However, oral gavage of In.Cr at different doses in rabbits showed a better brochodilation profile as compared to carbachol and K+-induced bronchospasm. More significant (p < 0.01) reduction in OVA-induced allergic hyper-responses i.e., inflammatory cells grade, antibody IgE as well as altered IFN-α in airways were observed at three different doses of In.Cr. It can be concluded that sound mechanistic basis i.e., the existence of antioxidants: various phenolic and flavonoids, calcium antagonist(s) as well as enzymes’ inhibition profile, validates folkloric consumptions of this traditionally used plant to treat ailments of respiration.

Integrated ONT Full-Length Transcriptome and Metabolism Reveal the Mechanism Affecting Ovulation in Muscovy Duck (Cairina moschata)

Ovulation is a complicated physiological process that is regulated by a multitude of different pathways. In comparison to mammalian studies, there are few reports of ovulation in Muscovy ducks, and the molecular mechanism of ovarian development remained unclear. In order to identify candidate genes and metabolites related to Muscovy duck follicular ovulation, the study combined Oxford Nanopore Technologies (ONT) full-length transcriptome and metabolomics to analyze the differences in gene expression and metabolite accumulation in the ovaries between pre-ovulation (PO) and consecutive ovulation (CO) Muscovy ducks. 83 differentially accumulated metabolites (DAMs) were identified using metabolomics analysis, 33 of which are related to lipids. Combined with data from previous transcriptomic analyses found that DEGs and DAMs were particularly enriched in processes including the regulation of glycerophospholipid metabolism pathway, arachidonic acid metabolic pathway and the steroid biosynthetic pathway. In summary, the novel potential mechanisms that affect ovulation in Muscovy ducks may be related to lipid metabolism, and the findings provide new insights into the mechanisms of ovulation in waterfowl and will contribute to a better understanding of changes in the waterfowl ovarian development regulatory network.

Omega-6 and Omega-3 Fatty Acid-Derived Oxylipins from the Lipoxygenase Pathway in Maternal and Umbilical Cord Plasma at Delivery and Their Relationship with Infant Growth

Omega-3 and omega-6 fatty acids are important for neonatal development and health. One mechanism by which omega-3 and omega-6 fatty acids exert their effects is through their metabolism into oxylipins and specialized pro-resolving mediators. However, the influence of oxylipins on fetal growth is not well understood. Therefore, the objective of this study was to identify oxylipins present in maternal and umbilical cord plasma and investigate their relationship with infant growth. Liquid chromatography-tandem mass spectrometry was used to quantify oxylipin levels in plasma collected at the time of delivery. Spearman's correlations highlighted significant correlations between metabolite levels and infant growth. They were then adjusted for maternal obesity (normal body mass index (BMI: ≤30 kg/m²) vs. obese BMI (>30 kg/m²) and smoking status (never vs. current/former smoker) using linear regression modeling. A p-value < 0.05 was considered statistically significant. Our study demonstrated a diverse panel of oxylipins from the lipoxygenase pathway present at the time of delivery. In addition, both omega-3 and omega-6 oxylipins demonstrated potential influences on the birth length and weight percentiles. The oxylipins present during pregnancy may influence fetal growth and development, suggesting potential metabolites to be used as biomarkers for infant outcomes.

Olive Oil Extracts and Oleic Acid Attenuate the LPS-Induced Inflammatory Response in Murine RAW264.7 Macrophages but Induce the Release of Prostaglandin E2

Olive oil contains high amounts of oleic acid (OA). Although OA has been described to inhibit inflammatory processes, the effects of olive oil on cellular mechanisms remain poorly understood. Therefore, we compared the effects of major fatty acids (FA) from olive oil with those of olive oil extracts (OOE) on inflammatory mediators and alterations in the cellular phospholipid composition in murine macrophages. Upon treatment with different OOE, FA compositions of lipopolysaccharide (LPS)-stimulated murine RAW264.7 macrophages were analyzed using gas chromatography. Olive oil extracts and OA significantly reduced the LPS-induced expression of inducible nitric oxide synthase (iNos), cyclooxygenase (Cox2), and interleukin-6 mRNA. In addition, a significant decrease in Cox2 and iNos protein expression was observed. The formation of nitric oxide was significantly reduced, while the formation of prostaglandin (PG) E2 from arachidonic acid significantly increased after treatment with OOE or OA. The latter was associated with a shift in the phospholipid FA composition from arachidonic acid to OA, resulting in an elevated availability of arachidonic acid. Together, OOE and OA mediate anti-inflammatory effects in vitro but increase the release of arachidonic acid and hereinafter PGE2, likely due to elongation of OA and competitive incorporation of fatty acids into membrane phospholipids.

Inflammation with the participation of arachidonic (AA) and linoleic acid (LA) derivatives (HETEs and HODEs) is necessary in the course of a normal reproductive cycle and pregnancy

Data on arachidonic (AA) and linoleic (LA) acid derivatives and their role in the reproductive cycle are limited. In order to systematize these reports, 54 scientific investigations were analyzed, which revealed the important role of AA and LA in the planning and course of pregnancy. Ovulation, menstruation, pregnancy, and childbirth are strongly related to the occurrence of physiological inflammatory reactions. Ovulation and menstruation are cyclic tissue remodeling processes that cause changes in the synthesis of inflammation mediators, such as prostaglandins and leukotrienes. Thus, the cyclooxygenase (COX) and lipoxygenase-5 (5-LOX) pathway for AA transformation is activated. Only the absence of neutrophils during this process differentiates an embryo implantation from a standard inflammatory response. It has been found that in COX-2 deficiency conditions, incorrect embryo implantation and decidual reaction occur; therefore, the mechanism associated with the activation of the nuclear factor (NF)-κB pathway seems to play an important role in the course of embryo implantation. In addition, 12/15-LOX may be key modulators of uterine activity during the implantation process. According to the current state of knowledge, AA derivatives synthesized throughout the cytochrome P450 (CYP) and LOX pathways play a special role in the late pregnancy period. Decreased 5-HETE levels have been related to slowing down the progression of labor, while 11-HETE and 15-HETrE to its acceleration. It has been also proven that renal 20-HETE contents undergo significant changes in the late pregnancy period, which are caused by an increase in their adrenal medulla and vascular synthesis, leading to decrease of blood pressure and an increase of sodium excretion, finally conditioning a normal course of labor.

Impact of Androgens on Inflammation-Related Lipid Mediator Biosynthesis in Innate Immune Cells

Rheumatoid arthritis, asthma, allergic rhinitis and many other disorders related to an aberrant immune response have a higher incidence and severity in women than in men. Emerging evidences from scientific studies indicate that the activity of the immune system is superior in females and that androgens may act as “immunosuppressive” molecules with inhibitory effects on inflammatory reactions. Among the multiple factors that contribute to the inflammatory response, lipid mediators (LM), produced from polyunsaturated fatty acids, represent a class of bioactive small molecules with pivotal roles in the onset, maintenance and resolution of inflammation. LM encompass pro-inflammatory eicosanoids and specialized pro-resolving mediators (SPM) that coexist in a tightly regulated balance necessary for the return to homeostasis. Innate immune cells including neutrophils, monocytes and macrophages possess high capacities to generate distinct LM. In the last decades it became more and more evident that sex represents an important variable in the regulation of inflammation where sex hormones play crucial roles. Recent findings showed that the biosynthesis of inflammation-related LM is sex-biased and that androgens impact LM formation with consequences not only for pathophysiology but also for pharmacotherapy. Here, we review the modulation of the inflammatory response by sex and androgens with a specific focus on LM pathways. In particular, we highlight the impact of androgens on the biosynthetic pathway of inflammation-related eicosanoids in innate immune cells.

Ginkgolic Acid is a Multi-Target Inhibitor of Key Enzymes in Pro-Inflammatory Lipid Mediator Biosynthesis

Introduction: Lipid mediators (LMs) comprise bioactive metabolites of polyunsaturated fatty acids, including pro-inflammatory prostaglandins (PGs), thromboxanes (TXs), and leukotrienes (LTs), as well as specialized pro-resolving mediators (SPMs). They are essentially biosynthesized via cyclooxygenase (COX) and lipoxygenase (LO) pathways in complex networks and regulate the progression as well as the resolution of inflammatory disorders including inflammation-triggered cancer. Ginkgolic acid (GA) is a phenolic acid contained in Ginkgo biloba L. with neuroprotective, antimicrobial, and antitumoral properties. Although LMs regulate microbial infections and tumor progression, whether GA affects LM biosynthesis is unknown and was investigated here in detail. Methods: Pharmacophore-based virtual screening was performed along with docking simulations. Activity assays were conducted for isolated human recombinant 5-LO, cytosolic phospholipase (PLA)2α, COX-2, and ovine COX-1. The activity of human mPGES-1 and thromboxane A2 synthase (TXAS) was determined in crude cellular fractions. Cellular LM formation was studied using human monocytes, neutrophils, platelets, and M1- and M2-like macrophages. LMs were identified after (ultra)high-performance liquid chromatography by UV detection or ESI-tandem mass spectrometry. Results: GA was identified as virtual hit in an mPGES-1 pharmacophore-based virtual screening. Cell-free assays revealed potent suppression of mPGES-1 activity (IC50 = 0.7 µM) that is fully reversible and essentially independent of the substrate concentration. Moreover, cell-free assays revealed COX-1 and TXAS as additional targets of GA with lower affinity (IC50 = 8.1 and 5.2 µM). Notably, 5-LO, the key enzyme in LT biosynthesis, was potently inhibited by GA (IC50 = 0.2 µM) in a reversible and substrate-independent manner. Docking simulations support the molecular interaction of GA with mPGES-1 and 5-LO and suggest concrete binding sites. Interestingly, interference of GA with mPGES-1, COX-1, TXAS, and 5-LO was evident also in intact cells with IC50 values of 2.1-3.8 µM; no radical scavenging or cytotoxic properties were obvious. Analysis of LM profiles from bacteria-stimulated human M1- and M2-like macrophages confirmed the multi-target features of GA and revealed LM redirection towards the formation of 12-/15-LO products including SPM. Conclusions: We reveal GA as potent multi-target inhibitor of key enzymes in the biosynthesis of pro-inflammatory LMs that contribute to the complex pharmacological and toxicological properties of GA.

Long-term effects of prior diets, dietary transition and pregnancy on adipose gene expression in dairy heifers

Adipose tissue is highly involved in whole-body metabolism and is the main site for lipid synthesis, storage and mobilization in ruminants. Therefore, knowledge about adipose tissue responses to different diets is important, especially in growing heifers as the feeding regimes of replacement heifers affect their future success as dairy cows. However, at gene expression level such knowledge is limited. As part of a larger feed trial, adipose tissue biopsies from 24 Norwegian Red heifers were collected at 12 months of age (12MO) and at month seven of gestation (PREG) and analyzed by next-generation mRNA sequencing. Between these two sampling points, all heifers had gone through a successful conception and a feed change from four dietary treatments of high or low energy (HE/LE) and protein (HP/LP) content (treatments LPHE, HPHE, LPLE and HPLE) to a low-energy, low-protein pregnancy feed given to all animals. Gene expression differences between different feed treatments at 12MO are described in an earlier publication from our group. The main objectives of this study were to investigate the long-term effects of diets differing in protein and energy density level on gene expression in adipose tissue of growing replacement dairy heifers. To achieve this, we examined the post-treatment effects between the treatment groups at month seven of gestation; 6 months after the termination of experimental feeding, and the long-term gene expression changes occurring in the adipose tissue between 12MO and PREG. Post-treatment group comparisons showed evidence of long-term effects of dietary treatment on adipose gene expression. Differences between protein treatments were smaller than between energy treatments. Adipose gene expression changes from 12MO to PREG were much larger for the HE than the LE treatments and seemed to mostly be explained by the characteristics of the diet change. 97 genes displayed a unidirectional expression change for all groups from 12MO to PREG, and are considered to be treatment-independent, possibly caused by pregnancy or increased age. This study provides candidate genes and key regulators for further studies on pregnancy preservation (TGFB1, CFD) and metabolic regulation and efficiency (PI3K, RICTOR, MAP4K4,) in dairy cattle.

Novel benzoxanthene lignans that favorably modulate lipid mediator biosynthesis: A promising pharmacological strategy for anti-inflammatory therapy

Lipid mediators (LM) encompass pro-inflammatory prostaglandins (PG) and leukotrienes (LT) but also specialized pro-resolving mediators (SPM) which display pivotal bioactivities in health and disease. Pharmacological intervention with inflammatory disorders such as osteoarthritis and rheumatoid arthritis commonly employs anti-inflammatory drugs that can suppress PG and LT formation, which however, possess limited effectiveness and side effects. Here, we report on the discovery and characterization of the two novel benzoxanthene lignans 1 and 2 that modulate select LM biosynthetic enzymes enabling the switch from pro-inflammatory LT to SPM biosynthesis as potential pharmacological strategy to intervene with inflammation. In cell-free assays, compound 1 and 2 inhibit microsomal prostaglandin E₂ synthase-1 and leukotriene C₄ synthase (IC₅₀ ∼ 0.6-3.4 µM) and potently interfere with 5-lipoxygenase (5-LOX), the key enzyme in LT biosynthesis (IC₅₀ = 0.04 and 0.09 µM). In human neutrophils, monocytes and M1 and M2 macrophages, compound 1 and 2 efficiently suppress LT biosynthesis (IC₅₀ < 1 µM), accompanied by elevation of 15-LOX-derived LM including SPM. In zymosan-induced murine peritonitis, compound 1 and 2 ameliorated self-limited inflammation along with suppression of early LT formation and elevation of subsequent SPM biosynthesis in vivo. Together, these novel benzoxanthene lignans promote the LM class switch from pro-inflammatory towards pro-resolving LM to terminate inflammation, suggesting their suitability as novel leads for pharmacotherapy of arthritis and related inflammatory disorders.

Discovery of new potent molecular entities able to inhibit mPGES-1

mPGES-1, a glutathione-dependent membrane protein is involved in the last step of PGE₂ production and has been well recognized as a strategic target for the development of anti-inflammatory and anti-cancer agents. It has been proven to selectively control the PGE₂ levels induced by inflammatory stimuli, with neither affecting PGE₂ constitutively produced, nor homeostatic prostanoids, so that its modulation can represent a better strategy to control PGE₂ related disorders, compared to the use of the classical anti-inflammatory drugs, endowed with severe side effects. Despite the intensive research on the identification of potent mPGES-1 inhibitors as attractive candidates for drug development, none of the disclosed molecules, except for LY3023705, which recently entered clinical trials, are available for clinical use, therefore the discovery of new effective mPGES-1 inhibitors with increased drug-like properties are urgently needed. Continuing our work aimed at identifying new chemical platforms able to interact with this enzyme, here we describe the discovery of potent mPGES-1 modulators, featuring a 1-fluoro-2,4-dinitro-biphenyl-based scaffold, by processing and docking a small collection of synthetically accessible molecules, built around two main fragments, disclosed in our in silico screening. The top scoring hits obtained have been synthesized and tested, and five of the predicted compounds showed to potently inhibit mPGES-1 enzyme, without affecting COX enzymes activities.

Androgen-mediated sex bias impairs efficiency of leukotriene biosynthesis inhibitors in males

Proinflammatory leukotrienes (LTs) are produced by 5-lipoxygenase (5-LO) aided by 5-LO-activating protein (FLAP). LT biosynthesis inhibitors are currently under clinical investigation as treatments for respiratory and cardiovascular diseases. Here, we have revealed a sex bias in the efficiency of clinically relevant LT biosynthesis inhibitors, showing that their effects are superior in females. We found that androgens cause these sex differences by impeding the LT-biosynthetic 5-LO/FLAP complex assembly. Lower doses of the FLAP inhibitor MK886 were required to reduce LTB4 levels in exudates of female versus male mice and rats. Following platelet-activating factor-induced shock, MK886 increased survival exclusively in female mice, and this effect was abolished by testosterone administration. FLAP inhibitors and the novel-type 5-LO inhibitors licofelone and sulindac sulfide exhibited higher potencies in human blood from females, and bioactive 5-LO/FLAP complexes were formed in female, but not male, human and murine leukocytes. Supplementation of female blood or leukocytes with 5α-dihydrotestosterone abolished the observed sex differences. Our data suggest that females may benefit from anti-LT therapy to a greater extent than males, prompting consideration of sex issues in LT modifier development.

Sex-biased eicosanoid biology: Impact for sex differences in inflammation and consequences for pharmacotherapy

The incidence, severity and progression of autoimmune diseases (e.g. scleroderma, multiple sclerosis, rheumatoid arthritis) and certain inflammatory diseases (e.g. asthma) are sex-biased where these pathologies dominate in women. However, other immune disorders such as sepsis, post-surgery infections and gout display higher incidence and severity in men. The molecular and cellular basis underlying this sex dimorphism remains incompletely elucidated but may provide important insights for sex-specific pharmacotherapy. Nevertheless, the sex as a variable in biochemical and preclinical research on inflammation is often neglected. Thus, respective animal studies are routinely performed with males, and experiments with isolated cells rarely report the sex of the donor. However, sex differences on the cellular level do exist, in particular related to inflammatory processes that prompt for sex-specific appreciation of inflammation research. For instance, the biosynthesis of pro-inflammatory eicosanoids is sex-biased where leukotriene (LT) formation is under control of testosterone that regulates the subcellular localization of the key enzyme 5-lipoxygenase, with possible implications for gender-tailored pharmacotherapy of LT-related disorders (i.e. asthma). Moreover, prostaglandin (PG) production is sex-biased, and sex-dependent efficacy of aspirin was evident in several clinical trials. Here, we highlight the sex bias in eicosanoid biology possibly underlying the obvious sex disparities in inflammation, stimulating scientists to take sex into account when studying the pathophysiology and pharmacotherapy of inflammatory diseases.

Anti-inflammatory and analgesic activity of carnosol and carnosic acid in vivo and in vitro and in silico analysis of their target interactions

BACKGROUND AND PURPOSE

The diterpenoids carnosol (CS) and carnosic acid (CA) from Salvia spp. exert prominent anti-inflammatory activities but their molecular mechanisms remained unclear. Here we investigated the effectiveness of CS and CA in inflammatory pain and the cellular interference with their putative molecular targets.

EXPERIMENTAL APPROACH

The effects of CS and CA in different models of inflammatory pain were investigated. The inhibition of key enzymes in eicosanoid biosynthesis, namely microsomal prostaglandin E2 synthase-1 (mPGES-1) and 5-lipoxygenase (5-LO) was confirmed by CS and CA, and we determined the consequence on the eicosanoid network in activated human primary monocytes and neutrophils. Molecular interactions and binding modes of CS and CA to target enzymes were analyzed by docking studies.

KEY RESULTS

CS and CA displayed significant and dose-dependent anti-inflammatory and anti-nociceptive effects in carrageenan-induced mouse hyperalgesia 4 h post injection of the stimuli, and also inhibited the analgesic response in the late phase of the formalin test. Moreover, both compounds potently inhibited cell-free mPGES-1 and 5-LO activity and preferentially suppressed the formation of mPGES-1 and 5-LO-derived products in cellular studies. Our in silico analysis for mPGES-1 and 5-LO supports that CS and CA are dual 5-LO/mPGES-1 inhibitors.

CONCLUSION AND IMPLICATIONS

In summary, we propose that the combined inhibition of mPGES-1 and 5-LO by CS and CA essentially contributes to the bioactivity of these diterpenoids. Our findings pave the way for a rational use of Salvia spp., traditionally used as anti-inflammatory remedy, in the continuous expanding context of nutraceuticals.

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

Human cells involved in atherosclerosis have a sex

The influence of sex has been largely described in cardiovascular diseases. Atherosclerosis is a complex process that involves many cell types such as vessel cells, immune cells and endothelial progenitor cells; however, many, if not all, studies do not report the sex of the cells. This review focuses on sex differences in human cells involved in the atherosclerotic process, emphasizing the role of sex hormones. Furthermore, we report sex differences and issues related to the processes that determine the fate of the cells such as apoptotic and autophagic mechanisms. The analysis of the data reveals that there are still many gaps in our knowledge regarding sex influences in atherosclerosis, largely for the cell types that have not been well studied, stressing the urgent need for a clear definition of experimental conditions and the inclusion of both sexes in preclinical studies.

BRP-187: A potent inhibitor of leukotriene biosynthesis that acts through impeding the dynamic 5-lipoxygenase/5-lipoxygenase-activating protein (FLAP) complex assembly

The pro-inflammatory leukotrienes (LTs) are formed from arachidonic acid (AA) in activated leukocytes, where 5-lipoxygenase (5-LO) translocates to the nuclear envelope to assemble a functional complex with the integral nuclear membrane protein 5-LO-activating protein (FLAP). FLAP, a MAPEG family member, facilitates AA transfer to 5-LO for efficient conversion, and LT biosynthesis critically depends on FLAP. Here we show that the novel LT biosynthesis inhibitor BRP-187 prevents the 5-LO/FLAP interaction at the nuclear envelope of human leukocytes without blocking 5-LO nuclear redistribution. BRP-187 inhibited 5-LO product formation in human monocytes and polymorphonuclear leukocytes stimulated by lipopolysaccharide plus N-formyl-methionyl-leucyl-phenylalanine (IC₅₀=7-10nM), and upon activation by ionophore A23187 (IC₅₀=10-60nM). Excess of exogenous AA markedly impaired the potency of BRP-187. Direct 5-LO inhibition in cell-free assays was evident only at >35-fold higher concentrations, which was reversible and not improved under reducing conditions. BRP-187 prevented A23187-induced 5-LO/FLAP complex assembly in leukocytes but failed to block 5-LO nuclear translocation, features that were shared with the FLAP inhibitor MK886. Whereas AA release, cyclooxygenases and related LOs were unaffected, BRP-187 also potently inhibited microsomal prostaglandin E₂ synthase-1 (IC₅₀=0.2μM), another MAPEG member. In vivo, BRP-187 (10mg/kg) exhibited significant effectiveness in zymosan-induced murine peritonitis, suppressing LT levels in peritoneal exudates as well as vascular permeability and neutrophil infiltration. Together, BRP-187 potently inhibits LT biosynthesis in vitro and in vivo, which seemingly is caused by preventing the 5-LO/FLAP complex assembly and warrants further preclinical evaluation.

Development of smart cell-free and cell-based assay systems for investigation of leukotriene C4 synthase activity and evaluation of inhibitors

Cysteinyl leukotrienes (cys-LTs) cause bronchoconstriction in anaphylaxis and asthma. They are formed by 5-lipoxygenase (5-LOX) from arachidonic acid (AA) yielding the unstable leukotriene A₄ (LTA₄) that is subsequently conjugated with glutathione (GSH) by LTC₄ synthase (LTC₄S). Cys-LT receptor antagonists and LTC₄S inhibitors have been developed, but only the former have reached the market. High structural homology to related enzymes and lack of convenient test systems due to instability of added LTA₄ have hampered the development of LTC₄S inhibitors. We present smart cell-free and cell-based assay systems based on in situ-generated LTA₄ that allow studying LTC₄S activity and investigating LTC₄S inhibitors. Co-incubations of microsomes from HEK293 cells expressing LTC₄S with isolated 5-LOX efficiently converted exogenous AA to LTC₄ (~1.3μg/200μg protein). Stimulation of HEK293 cells co-expressing 5-LOX and LTC₄S with Ca²⁺-ionophore A23187 and 20μM AA resulted in strong LTC₄ formation (~250ng/10⁶ cells). MK-886, a well-known 5-LOX activating protein (FLAP) inhibitor that also acts on LTC₄S, consistently inhibited LTC₄ formation in all assay types (IC₅₀=3.1-3.5μM) and we successfully confirmed TK04a as potent LTC₄S inhibitor in these assay systems (IC₅₀=17 and 300nM, respectively). We demonstrated transcellular LTC₄ biosynthesis between neutrophils or 5-LOX-expressing HEK293 cells that produce LTA₄ from AA and HEK293 cells expressing LTC₄S that transform LTA₄ to LTC₄. In conclusion, our assay approaches are advantageous as the substrate LTA₄ is generated in situ and are suitable for studying enzymatic functionality of LTC₄S including site-directed mutations and evaluation of LTC₄S inhibitors.

Synthesis and biological evaluation of C(5)-substituted derivatives of leukotriene biosynthesis inhibitor BRP-7

Pharmacological intervention with 5-lipoxygenase (5-LO) pathway leading to suppression of leukotriene (LT) biosynthesis is a clinically validated strategy for treatment of respiratory and cardiovascular diseases such as asthma and atherosclerosis. Here we describe the synthesis of a series of C(5)-substituted analogues of the previously described 5-LO-activating protein (FLAP) inhibitor BRP-7 (IC50 = 0.31 μM) to explore the effects of substitution at the C(5)-benzimidazole (BI) ring as a strategy to increase the potency against FLAP-mediated 5-LO product formation. Incorporation of polar substituents on the C(5) position of the BI core, exemplified by compound 11 with a C(5)-nitrile substituent, significantly enhances the potency for suppression of 5-LO product synthesis in human neutrophils (IC50 = 0.07 μM) and monocytes (IC50 = 0.026 μM).

Pharmacotherapy options to treat asthma during pregnancy

INTRODUCTION

Pregnancy may be complicated by new onset or pre-existing asthma. This article reviews the recognition and management of asthma during pregnancy, paying close attention to the general principles of asthma medication use during pregnancy. Asthma is one of the most common potentially serious medical problems to complicate pregnancy, and asthma may adversely affect both maternal quality of life and perinatal outcomes. Therefore, optimal management of asthma during pregnancy is important for both mother and baby. This article reviews asthma pharmacotherapy during pregnancy, with an emphasis on gestational safety of commonly used medications.

AREAS COVERED

In this review of asthma pharmacotherapy during pregnancy, the most pertinent recent publications are reported. Electronic databases such as PubMed were searched for terms pregnan* or perinat* or obstet* and asthma or wheeze and treatment.

EXPERT OPINION

Although retrospective data have been reassuring, since pregnant women are generally excluded from clinical trials, there is a lack of adequate safety information for most medications taken during pregnancy. One of the most important needs for the future is the availability of further safety information for asthma medications used during pregnancy that can also account for asthma control.

α-Tocopherol long-chain metabolite α-13'-COOH affects the inflammatory response of lipopolysaccharide-activated murine RAW264.7 macrophages

SCOPE

Inflammatory response of macrophages is regulated by vitamin E forms. The long-chain metabolite α-13'-carboxychromanol (α-13'-COOH) is formed by hepatic α-tocopherol (α-TOH) catabolism and acts as a regulatory metabolite via pathways that are different from its metabolic precursor.

METHODS AND RESULTS

Using semisynthetically-derived α-13'-COOH we profiled its action on LPS-induced expression of pro- and anti-inflammatory genes using RT-qPCR and of key proteins by Western blotting. Effects on inflammatory response were assessed by measuring production of nitric oxide and prostaglandin (PG) E2 , PGD2 , and PGF2α. α-13'-COOH inhibits proinflammatory pathways in LPS-stimulated RAW264.7 macrophages more efficiently than α-TOH. Profiling inflammation-related genes showed significant blocking of interleukin (Il)1β by the metabolite and its precursor as well, while upregulation of Il6 was not impaired. However, induction of Il10, cyclooxygenase 2 (Cox2) and inducible nitric oxide synthase (iNos) by LPS and consequently the formation of nitric oxide and PG was significantly reduced by α-13'-COOH. Interestingly, α-13'-COOH acted independently from translocation of NFκB subunit p65.

CONCLUSION

Our study sheds new light on the mode of action of α-TOH on the inflammatory response in macrophages, which may be mediated in vivo at least in part by its metabolite α-13'-COOH. Our data show that α-13'-COOH is a potent anti-inflammatory molecule.

Risk of acute appendicitis in and around pregnancy: a population-based cohort study from England

OBJECTIVE

To determine the absolute and relative risk of acute appendicitis during the antepartum and postpartum periods compared with the time outside pregnancy among women of childbearing age.

BACKGROUND

Acute appendicitis is the most common nonobstetric surgical emergency during pregnancy. Estimates of the incidence of acute appendicitis in pregnancy remain imprecise and inconsistent.

METHODS

All potential fertile women aged 15 to 44 years registered within Clinical Practice Research Datalink with linkages to the Hospital Episodes Statistics between 1997 and 2012 were identified. Absolute rates of acute appendicitis were calculated during the antepartum and postpartum periods and were compared with the time outside pregnancy in terms of incidence rate ratio (IRR) using a Poisson regression model.

RESULTS

Among 1,624,804 women, there were 362,219 pregnancies resulting in live or stillbirths. Compared with the time outside pregnancy, the rate of acute appendicitis was 35% lower during the antepartum period [IRR, 0.65; 95% confidence interval (CI), 0.55-0.76], with the lowest rate reported during the third trimester (IRR, 0.47; 95% CI, 0.35-0.64) for all ages; no increased risk of acute appendicitis was observed in the postpartum period compared with the time outside pregnancy among women aged 15 to 34 years but an 84% increased risk for women older than 35 years (IRR, 1.84; 95% CI, 1.18-2.86). The highest and lowest rates of negative appendectomy were encountered in the second and the third trimesters, respectively.

CONCLUSIONS

Pregnant women are less likely to be diagnosed with acute appendicitis than nonpregnant women, with the lowest risk reported during the third trimester.

Progesterone rapidly down-regulates the biosynthesis of 5-lipoxygenase products in human primary monocytes

5-Lipoxygenase (5-LO), the key enzyme in the biosynthesis of pro-inflammatory leukotrienes (LTs) from arachidonic acid, is regulated by androgens in human neutrophils and monocytes accounting for sex differences in LT formation. Here we show that progesterone suppresses the synthesis of 5-LO metabolites in human primary monocytes. 5-LO product formation in monocytes stimulated with Ca(2+)-ionophore A23187 or with lipopolysaccharide/formyl peptide was suppressed by progesterone at concentrations of 10-100 nM in cells from females and at 1 μM in cells from males. Progesterone down-regulated 5-LO product formation in a rapid and reversible manner, but did not significantly inhibit 5-LO activity in cell-free assays using monocyte homogenates. Also, arachidonic acid release and its metabolism to other eicosanoids in monocytes were not significantly reduced by progesterone. The inhibitory effect of progesterone on LTs was still observed when mitogen-activated protein kinases were pharmacologically blocked, stimulatory 1-oleoyl-2-acetyl-sn-glycerol was exogenously supplied, or extracellular Ca(2+) was removed by chelation. Instead, suppression of PKA by means of two different pharmacological approaches (i.e. H89 and a cell-permeable PKA inhibitor peptide) prevented inhibition of 5-LO product generation by progesterone, to a similar extent as observed for the PKA activators prostaglandin E2 and 8-Br-cAMP, suggesting the involvement of PKA. In summary, progesterone affects the capacity of human primary monocytes to generate 5-LO products and, in addition to androgens, may account for sex-specific effects on pro-inflammatory LTs.

Safety of therapeutic options for treating asthma in pregnancy

INTRODUCTION

Pregnancy may be complicated by new onset or preexisting asthma. Asthma is one of the most common potentially serious medical problems to complicate pregnancy, and it may adversely affect both maternal quality of life and perinatal outcomes. Optimal management of asthma during pregnancy is thus important for both mother and baby.

AREAS COVERED

This article reviews the recognition and management of asthma during pregnancy, paying close attention to the general principles of asthma medication use during pregnancy. Further, the article reviews the safety of asthma medications commonly used during pregnancy. In this article, the most pertinent recent publications are reported. Electronic databases, such as PUBMED, were searched for terms pregnan* or perinat* or obstet* and asthma or wheeze and treatment.

EXPERT OPINION

Because pregnant women are generally excluded from clinical trials, there is a lack of adequate safety information for most medications taken during pregnancy. One of the most important requirements for the future is the availability of further safety information for asthma medications used during pregnancy that can also account for asthma control.

In-vitro and in-vivo validation of ethnopharmacological uses of methanol extract of Isodon rugosus Wall. ex Benth. (Lamiaceae)

BACKGROUND

Isodon rugosus is used in folk Pakistan traditional practices to cure ailments related to gastrointestinal, respiratory and cardiovascular problems. Present study was undertaken to validate these folkloric uses.

METHODS

A crude methanol extract of the aerial parts of Isodon rugosus (Ir.Cr.) was used for both in vitro and in vivo experiments. The plant extract was tested on isolated rabbit jejunum preparations for possible presence of spasmolytic activity. Moreover, isolated rabbit tracheal and aorta preparations were used to ascertain the relaxant effects of the extract. Acetylcholinesterase and butyrylcholinesterase inhibitory activities of Ir.Cr were also determined as well as its antioxidant activity. The in vivo antiemetic activity of the extract was evaluated by using the chick emesis model, while the analgesic and antipyretic activities were conducted on albino mice.

RESULTS

The application of the crude extract of I. rugosus to isolated rabbit jejunum preparations exhibited relaxant effect (0.01-0.3 mg/ml). The Ir.Cr also relaxed K+(80 m M)-induced spastic contractions in isolated rabbit jejunum preparations and shifted the Ca+2 concentration response curves towards right (0.01-0.3 mg/ml). Similarly, the extract, when applied to the isolated rabbit tracheal preparations relaxed the carbachol (1 μM)--as well as K+ (80 mM)-induced contractions in a concentration range of 0.01-1.0 mg/ml. Moreover, it also relaxed (0.01-3.0 mg/ml) the phenylephrine (1 μM)- and K+ (80 mM)-induced contractions in isolated rabbit aorta preparations. The Ir.Cr (80 mg/kg) demonstrated antipyretic activity on pyrogen-induced pyrexia in rabbits as compared to aspirin as standard drug. The Ir.Cr also exhibited anti-oxidant as well as inhibitory effect on acetyl- and butyryl-cholinesterase and lipoxygenase (0.5 mg/ml).

CONCLUSIONS

The observed relaxant effect on isolated rabbit jejunum, trachea and aorta preparations caused by Ir.Cr is possibly to be mediated through Ca+2 channel blockade and therefore may provided scientific basis to validate the folkloric uses of the plant in the management of gastrointestinal, respiratory and cardiovascular ailments. The observed antioxidant activity as well as the lipoxygenase inhibitory activity may validate its traditional use in pain and inflammations.