Products Of Arachidonic Acid Metabolism Research Articles

Cyclooxygenase products contribute to the exaggerated exercise pressor reflex evoked by static muscle contraction in male UCD-type 2 diabetes mellitus rats.

Cyclooxygenase (COX) products of arachidonic acid metabolism, specifically prostaglandins, play a role in evoking and transmitting the exercise pressor reflex in health and disease. Individuals with type 2 diabetes mellitus (T2DM) have an exaggerated exercise pressor reflex; however, the mechanisms for this exaggerated reflex are not fully understood. We aimed to determine the role played by COX products in the exaggerated exercise pressor reflex in T2DM rats. The exercise pressor reflex was evoked by static muscle contraction in unanesthetized, decerebrate, male, adult University of California Davis (UCD)-T2DM (n = 8) and healthy Sprague-Dawley (n = 8) rats. Changes (Δ) in peak mean arterial pressure (MAP) and heart rate (HR) during muscle contraction were compared before and after intra-arterial injection of indomethacin (1 mg/kg) into the contracting hindlimb. Data are presented as means ± SD. Inhibition of COX activity attenuated the exaggerated peak MAP (Before: Δ32 ± 13 mmHg and After: Δ18 ± 8 mmHg; P = 0.004) and blood pressor index (BPi) (Before: Δ683 ± 324 mmHg·s and After: Δ361 ± 222 mmHg·s; P = 0.006), but not HR (Before: Δ23 ± 8 beats/min and After Δ19 ± 10 beats/min; P = 0.452) responses to muscle contraction in T2DM rats. In healthy rats, COX activity inhibition did not affect MAP, HR, or BPi responses to muscle contraction. Inhibition of COX activity significantly reduced local production of prostaglandin E2 in T2DM and healthy rats. We conclude that peripheral inhibition of COX activity attenuates the pressor response to muscle contraction in T2DM rats, suggesting that COX products partially contribute to the exaggerated exercise pressor reflex in those with T2DM.NEW & NOTEWORTHY We compared the pressor and cardioaccelerator responses to static muscle contraction before and after inhibition of cyclooxygenase (COX) activity within the contracting hindlimb in decerebrate, unanesthetized type 2 diabetic mellitus (T2DM) and healthy rats. The pressor responses to muscle contraction were attenuated after peripheral inhibition of COX activity in T2DM but not in healthy rats. We concluded that COX products partially contribute to the exaggerated pressor reflex in those with T2DM.

Leukotrienes in the atherosclerotic cardiovascular diseases — a systematic review

Introduction: The role of inflammation in the pathogenesis of atherosclerotic diseases is strongly suggested. There are multiple studies indicating the possibility of a pathophysiological connection between atherosclerotic changes and leukotrienes (LTs) — the products of arachidonic acid metabolism. The goal of this systematic review, performed in line with the PRISMA statement, was to investigate the potential role of LTs in the pathophysiology of atherosclerotic cardiovascular diseases (CVD). Material and methods: The MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews were searched to identify the potentially eligible studies. Publications that contained information on any type of LTs identified in blood or urine were included in the review. A database search identified 2082 records. Reliable LTs identification in patients with CVD was used in 30 publications. Results: Stable and acute forms of coronary artery disease are characterized by the overproduction of different types of LTs. The level of LTB4 and LTC4 in the blood is elevated in patients with cerebral ischemia. Patients with acute and chronic peripheral artery disease have elevated levels of LTE4 in urine. Conclusions: The findings of this systematic review show that there is a clear tendency to indicate the association of cardiovascular atherosclerotic diseases with increased production of LTs. This dependency detailed characteristic remains unclear and the question on the impact of elevated leukotrienes on clinical atherosclerotic disease manifestations is still open.

Identification of AGR2 Gene-Specific Expression Patterns Associated with Epithelial-Mesenchymal Transition.

The TGF-β signaling pathway is involved in numerous cellular processes, and its deregulation may result in cancer development. One of the key processes in tumor progression and metastasis is epithelial to mesenchymal transition (EMT), in which TGF-β signaling plays important roles. Recently, AGR2 was identified as a crucial component of the cellular machinery responsible for maintaining the epithelial phenotype, thereby interfering with the induction of mesenchymal phenotype cells by TGF-β effects in cancer. Here, we performed transcriptomic profiling of A549 lung cancer cells with CRISPR-Cas9 mediated AGR2 knockout with and without TGF-β treatment. We identified significant changes in transcripts associated with focal adhesion and eicosanoid production, in particular arachidonic acid metabolism. Changes in transcripts associated with the focal adhesion pathway were validated by RT-qPCR of COL4A1, COL4A2, FLNA, VAV3, VEGFA, and VINC mRNAs. In addition, immunofluorescence showed the formation of stress fibers and vinculin foci in cells without AGR2 and in response to TGF-β treatment, with synergistic effects observed. These findings imply that both AGR2 downregulation and TGF-β have a role in focal adhesion formation and cancer cell migration and invasion. Transcripts associated with arachidonic acid metabolism were downregulated after both AGR2 knockout and TGF-β treatment and were validated by RT-qPCR of GPX2, PTGS2, and PLA2G4A. Since PGE2 is a product of arachidonic acid metabolism, its lowered concentration in media from AGR2-knockout cells was confirmed by ELISA. Together, our results demonstrate that AGR2 downregulation and TGF-β have an essential role in focal adhesion formation; moreover, we have identified AGR2 as an important component of the arachidonic acid metabolic pathway.

Genetic analyses of circulating PUFA-derived mediators identifies heritable dihydroxyeicosatrienoic acid species

Estimates of heritability are the first step in identifying a trait with substantial variation due to genetic factors. Large-scale genetic analyses can identify the DNA variants that influence the levels of circulating lipid species and the statistical technique Mendelian randomisation can use these DNA variants to address potential causality of these lipids in disease. We estimated the heritability of plasma eicosanoids, octadecanoids and docosanoids to identify those lipid species with substantial heritability. We analysed plasma lipid mediators in 31 White British families (196 participants) ascertained for high blood pressure and deeply clinically and biochemically phenotyped over a 25-year period. We found that the dihydroxyeicosatrienoic acid (DHET) species, 11,12-DHET and 14,15-DHET, products of arachidonic acid metabolism by cytochrome P450 (CYP) monooxygenase and soluble epoxide hydrolase (sEH), exhibited substantial heritability (h2 = 33%−37%; Padj<0.05). Identification of these two heritable bioactive lipid species allows for future large-scale, targeted, lipidomics-genomics analyses to address causality in cardiovascular and other diseases.

Arnika górska jako roślina lecznicza

The pharmacological properties of arnica flowers are mainly due to the action of sesquiterpene lactones and flavonoids. The mechanism of the anti-inflammatory action of Arnicae flos (in vitro studies) is based on the inhibition of the release of pro-inflammatory factors: NF-κB, NF-AT and metabolic products of arachidonic acid. This herbal substance is used only externally in blunt injuries (contusions, sprains, bruises), as well as in muscle and rheumatic pains. Strong antimicrobial properties, equal to the activity of antibiotics, justify the use of arnica flowers in dermatoses.

New Substituted 5-Benzylideno-2-Adamantylthiazol[3,2-b][1,2,4]Triazol-6(5H)ones as Possible Anti-Inflammatory Agents.

Background: Inflammation is a complex response to noxious stimuli promoted by the release of chemical mediators from the damaged cells. Metabolic products of arachidonic acid, produced by the action of cyclooxygenase and lipoxygenase, play important roles in this process. Several non-steroidal anti-inflammatory drugs act as cyclooxygenase inhibitors. However, almost all of them have undesired side effects. Methods: Prediction of the anti-inflammatory action of the compounds was performed using PASS Program. The anti-inflammatory activity was evaluated by the carrageenan paw edema test. COX and LOX inhibitory actions were tested using ovine COX-1, human recombinant COX-2 and soybean LOX-1, respectively. Docking analysis was performed using Autodock. Results: All designed derivatives had good prediction results according to PASS and were synthesized and experimentally evaluated. The compounds exhibited in vivo anti-inflammatory action with eleven being equal or better than indomethacin. Although, some of them had no or low inhibitory effect on COX-1/2 or LOX, certain compounds exhibited COX-1 inhibition much higher than naproxen and COX-2 inhibition, well explained by Docking analysis. Conclusions: A number of compounds with good anti-inflammatory action were obtained. Although, some exhibited remarkable COX inhibitory action this activity did not follow the anti-inflammatory results, indicating the implication of other mechanisms.

Endoperoxide 4 receptor inhibition has no effect on the pressor response evoked during isolated mechanoreflex activation in rats with heart failure

BackgroundThe stimulation of primarily mechanically sensitive group III and primarily metabolically sensitive group IV muscle afferents during skeletal muscle contractions evokes reflex increases in blood pressure (i.e., the exercise pressor reflex) and facilitates exercise performance. Heart failure patients with reduced ejection fraction (HF‐rEF) exhibit an exaggerated exercise pressor reflex, leading to excessive peripheral vasoconstriction and impaired limb blood flow during exercise. The exaggerated exercise pressor reflex in HF‐rEF is attributed, at least in part, to an exaggeration of the mechanically sensitive portion of the reflex (i.e., the mechanoreflex). Furthermore, multiple lines of evidence suggest that, in HF‐rEF, the mechanoreflex sensitization is attributable to the cyclooxygenase products of arachidonic acid metabolism. For example, recent evidence in a rat model of HF‐rEF induced by myocardial infarction demonstrated that the exaggerated rise in renal sympathetic nerve activity during hindlimb muscle stretch (a model of mechanoreflex activation) was significantly reduced following inhibition of the COX‐2 isoform that predominately produces prostaglandin E2 (PGE2). However, the COX metabolite receptor on sensory neurons that mediated the PGE2‐induced mechanoreflex sensitization in HF‐rEF is not known.Purpose &amp; HypothesisOur purpose was to determine the effect of inhibition of the PGE2 receptor endoperoxide 4 (EP4) on mechanoreflex activation in rats with HF‐rEF. We hypothesized that hindlimb arterial injection of the EP4 receptor antagonist L‐161,982 would reduce the exaggerated increase in MAP during 30 s of static hindlimb muscle stretch in rats with HF‐rEF, but not in healthy control rats.MethodsWe utilized a rat model of HF‐rEF in which the left main coronary artery is ligated with 5‐0 suture to induce myocardial infarction (n=7). Control rats (n=3) were subjected to a sham ligation in which the suture was passed under the artery but not tied. At least four weeks after the initial surgery, in decerebrate, unanesthetized rats we compared (paired Student’s t‐tests) the pressor response (peak ΔMAP) evoked during muscle stretch before and after the injection of L‐161,982 (1 μg) into the arterial supply of the hindlimb circulation.ResultsEjection fraction determined via echocardiography was significantly reduced in HF‐rEF rats (35±6%) compared to sham rats (82±2%, p&lt;0.01, unpaired Student’s t‐test). We found that EP4 receptor inhibition had no effect during hindlimb muscle stretch on the peak ΔMAP in either HF‐rEF rats (pre: 24±4; post: 26±6mmHg; p=0.74) or sham rats (pre: 13±3; post: 11±2mmHg; p=0.23). Moreover, western blot analysis revealed no difference between HF‐rEF and sham rats in protein expression of EP4 receptor within the L4 and L5 dorsal root ganglia (unpaired Student’s t‐test; p=0.25).ConclusionsThe present data suggest that that EP4 receptors do not contribute to the exaggerated mechanoreflex evoked in rats with HF‐rEF. Our data enhance the understanding of the blood pressure control during exercise in the ~6 million Americans currently diagnosed with HF‐rEF.Support or Funding InformationNational Institutes of Health Grant HL‐142877 to SWC

Yunnan Baiyao diminishes lipopolysaccharide-induced inflammation in osteoclasts.

Yunnan Baiyao (YNBY) has been refined for hundreds of years and has become a treasure of proprietary Chinese medicine that has significant curative effects in the field of hemostasis, blood circulation, and callus. In past years, YNBY has been demonstrated to play an anti-inflammatory role in bone-related diseases, such as rheumatoid arthritis and osteoporosis. However, the osteoclasts are multinucleated giant cells that resorb bone and participate in the occurrence, development, and progression of these bone-related diseases. Previous studies have reported that the inflammatory function is closely associated with arachidonic acid (AA) metabolism, as well as some inflammatory-related pathways, including the nuclear factor кB (NF-кB), mitogen-activated protein kinase (MAPK), and Wnt5a pathways. Therefore, we speculated that the anti-inflammatory effect of YNBY might be associated with the NF-кB, MAPK, and Wnt5a pathways. In order to further excavate the anti-inflammatory roles of YNBY, lipopolysaccharide (LPS) with an optimal concentration of 1,000pg/ml was used to induce inflammation in osteoclasts. Our results showed that YNBY with a time- and dose-dependent method decreased the concentration of pro-inflammatory cytokines and the expression levels of cyclooxygenase-1 (COX-1), COX-2, 5-lipoxygenase, and prostaglandin E2. Moreover, it was found that COX-2 was the target gene regulated by YNBY. Finally, using NF-кB and MAPK pathway inhibitors or miRNA101b (involved in the Wnt5a pathway) in tandem with YNBY and the results exhibited that these groups caused a reduction in COX-1 and COX-2 expression, indicating that the anti-inflammatory function of YNBY might directly affect the NF-кB, MAPK, and Wnt5a pathways. PRACTICAL APPLICATIONS: Yunnan Baiyao (YNBY) is mainly extracted from precious Chinese medicines such as Panax notoginseng, borneol, musk, and yam and has a wide range of clinical applications. It is not only used to treat various types of traumatic injuries, but also used for upper gastrointestinal bleeding and wound ulcers, neonatal umbilitis, recurrent oral ulcers, esophagitis, bacterial dysentery, and so on. Although the detailed mechanism of action is not clear at present, it is believed that this is related to its anti-inflammatory, hemostatic, and immune-enhancing effects. Many bone-related diseases, such as rheumatoid arthritis and osteoporosis, are regarded to be intimately related to the inflammatory reaction. Thus, this study aimed to explore the underlying mechanisms of YNBY at anti-inflammatory roles. And our results suggested that YNBY directly affected the inflammatory cytokines and AA metabolic products which referred to the NF-кB, MAPK, and Wnt5a pathways, as well as AA metabolism, respectively. Hence, the practical applications of YNBY are the anti-inflammatory effects used to treat for bone-related diseases.

PTUPB ameliorates high-fat diet-induced non-alcoholic fatty liver disease via inhibiting NLRP3 inflammasome activation in mice

Non-alcoholic fatty liver disease (NAFLD) affects 25% of the global adult population, and no effective pharmacological treatment has been found. Products of arachidonic acid metabolism have been developed into a novel therapy for metabolic syndrome and diabetes. It has been demonstrated that protective actions of a novel dual cyclooxygenase-2 (COX-2) and soluble epoxide hydrolase (sEH) inhibitor, PTUPB, on the metabolic abnormalities. Here, we investigated the effects of PTUPB on hepatic steatosis in high-fat diet (HFD)-induced obese mice, as well as in hepatocytes in vitro. We found that PTUPB treatment reduced body weight, liver weight, liver triglyceride and cholesterol content, and the expression of lipolytic/lipogenic and lipid uptake related genes (Acc, Cd36, and Cidec) in HFD mice. In addition, PTUPB treatment arrested fibrotic progression with a decrease of collagen deposition and expression of Col1a1, Col1a3, and α-SMA. In vitro, PTUPB decreased palmitic acid-induced lipid deposition and downregulation of lipolytic/lipogenic genes (Acc and Cd36) in hepatocytes. Additionally, we found that PTUPB reduced the production of pro-inflammatory cytokines and suppressed the NLRP3 inflammasome activation in HFD mice and hepatocytes. In conclusion, dual inhibition of COX-2/sEH attenuates hepatic steatosis by inhibiting the NLRP3 inflammasome activation. PTUPB might be a promising potential therapy for liver steatosis associated with obesity.

Markers of endothelial dysfunction: pathogenetic role and diagnostic significance.

Endothelial dysfunction (ED) is considered one of the pathogenetic mechanisms of a whole range of diseases. Detection of specific biochemical markers in the blood is an effective way to ED diagnostics that characterize the vascular endothelium state. This review highlights the pathogenetic role of the factors synthesized by endotheliocytes whose level changes in biological fluids reflect violations of the endothelium basic physiological properties: vasomotor function, thromboresistance, angiogenesis regulation, barrier and adhesion functions. In particular, the participation of nitric oxide metabolites, asymmetric dimethylarginine, endothelin-1, metabolic products of arachidonic acid, von Willebrand factor, thrombomodulin, vascular endothelial growth factor, vasohibine-1 and adhesion molecules in the onset and development of ED are reviewed. The diagnostic significances of factors damaging endothelium, such as C-reactive protein, homocysteine and 8-hydroxy-2'-deoxyguanosine, are discussed. In addition, the literature data of recent years about the prospects of clinical implication the detection of the above-mentioned factors which indicates structural and functional endothelial cells damage are given. Particular attention is paid to the ED markers detection prognostic significance and the possibility of their practical use for the ED diagnosis. The search of literature for the current review was conducted in RSIC, CyberLeninka, Scopus, Web of Science, MedLine and PubMed databases from 2012 to 2018 using the following keywords: endothelial dysfunction, nitric oxide, asymmetric dimethylarginine, endothelin-1, prostacyclin, thromboxane A2, epoxyeicosatrienoic acids, von Willebrand factor, thrombomodulin, vascular endothelial growth factor, vasohibin-1, adhesive molecules, C-reactive protein, homocysteine, and 8-hydroxy-2-deoxyguanosine.

MARKERS OF ENDOTHELIAL DYSFUNCTION: PATHOGENETIC ROLE AND DIAGNOSTIC SIGNIFICANCE

Endothelial dysfunction (ED) is considered one of the pathogenetic mechanisms of a whole range of diseases. Detection of specific biochemical markers in the blood is an effective way to ED diagnostics that characterize the vascular endothelium state. This review highlights the pathogenetic role of the factors synthesized by endotheliocytes whose level changes in biological fluids reflect violations of the endothelium basic physiological properties: vasomotor function, thromboresistance, angiogenesis regulation, barrier and adhesion functions. In particular, the participation of nitric oxide metabolites, asymmetric dimethylarginine, endothelin-1, metabolic products of arachidonic acid, von Willebrand factor, thrombomodulin, vascular endothelial growth factor, vasohibine-1 and adhesion molecules in the onset and development of ED are reviewed. The diagnostic significances of factors damaging endothelium, such as C-reactive protein, homocysteine and 8-hydroxy-2’-deoxyguanosine, are discussed. In addition, the literature data of recent years about the prospects of clinical implication the detection of the above-mentioned factors which indicates structural and functional endothelial cells damage are given. Particular attention is paid to the ED markers detection prognostic significance and the possibility of their practical use for the ED diagnosis. The search of literature for the current review was conducted in RSIC, CyberLeninka, Scopus, Web of Science, MedLine and PubMed databases from 2012 to 2018 using the following keywords: endothelial dysfunction, nitric oxide, asymmetric dimethylarginine, endothelin-1, prostacyclin, thromboxane A2, epoxyeicosatrienoic acids, von Willebrand factor, thrombomodulin, vascular endothelial growth factor, vasohibin-1, adhesive molecules, C-reactive protein, homocysteine, and 8-hydroxy-2-deoxyguanosine.

Metabolomics profiling of haloperidol and validation of thromboxane-related signaling in the early development of zebrafish

Haloperidol is a common butyrophenone-derivative antipsychotic drug that is used clinically to treat schizophrenia and to control Tourette disorder. Haloperidol has been shown to be an embryonic toxicant and to cause a variety of adverse effects that affect human embryonic development. However, the pathway impaired by haloperidol during the developmental stages remains unclear. To elucidate the innate toxicological pathway of haloperidol, we investigated the lethality of haloperidol during the embryonic development of zebrafish. We observed that haloperidol caused serious morphological changes, with an LD50 of 9.7 x 10−6 ± 2.4 x 10−6 μg/L. Next, we established a systematic approach to perform metabolite profiling in embryonic zebrafish with various concentrations of haloperidol and analyzed the metabolites using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS). A total of 304 metabolites were identified and 86 metabolites were chosen to predict potential pathways. Among the metabolites, we found through prediction that numerous metabolomics-biological pathways are associated with haloperidol, including peroxisome-proliferator-activated receptor (ppar), thromboxane, and mTOR signaling. Quantitative real time-qPCR was then used to validate the gene expression potentially associated with the thromboxane, which is a metabolic product of arachidonic acid and considered to be important for cell proliferation and the inflammatory response. To sum up, analysis of metabolites in the zebrafish model provides a system for mining biomarkers that reflect biological significance and highlight the therapeutic potency in humans. In addition, it may show potential for application to other pharmaceuticals to identify their various activities and clarify functional mechanisms in the future.

12-HETE facilitates cell survival by activating the integrin-linked kinase/NF-κB pathway in ovarian cancer.

BackgroundThe dysfunction of cell apoptosis is an important event in the progression of cancer, and the growth of cancer cells is negatively regulated by cell apoptosis. In different types of cancers, inhibition of cellular apoptosis is often observed in the cancerous tissue, and increased resistance to apoptosis is a hallmark of cancer. Although previous studies have shown that 12-lipoxygenase (12-LOX)/12-hydroxyeicosatetraenoic acid (12-HETE) is activated and upregulated in different types of cancers, the consequences of 12-LOX/12-HETE upregulation and its precise roles in the survival of ovarian carcinoma cells are still unknown.MethodsMTT assays, caspase activity assays, lactate dehydrogenase (LDH) assays, and Western blot analysis were the methods used in this study.ResultsIn our study, we found that 12-HETE, a major metabolic product of arachidonic acid using 12-LOX catalysis, inhibited cell apoptosis in a dose-dependent manner and that the effects of 12-HETE on cell apoptosis were mediated by the integrin-linked kinase (ILK) pathway. Moreover, the downstream target of 12-HETE-activated ILK was nuclear factor kappa-B (NF-κB) in ovarian carcinoma. The inhibitory effects of 12-HETE on cell apoptosis were attenuated by the inhibition of the NF-κB pathway.ConclusionThese results indicate that 12-HETE participates in the inhibition of cell apoptosis by activating the ILK/NF-κB pathway, implying an important underlying mechanism that promotes the survival of ovarian cancer cells.

Lipoxin A4 inhibits UV radiation-induced skin inflammation and oxidative stress in mice

BackgroundLipoxin A4 (LXA4) is a metabolic product of arachidonic acid. Despite potent anti-inflammatory and pro-resolution activities, it remains to be determined if LXA4 has effect on ultraviolet (UV) radiation-induced skin inflammation. ObjectiveTo investigate the effects of systemic administration with LXA4 on UV radiation-induced inflammation and oxidative damage in the skin of mice. MethodsVaried parameters of inflammation and oxidative stress in the skin of mice were evaluated after UV radiation (4.14 J/cm2). ResultsPretreatment with LXA4 significantly inhibited UV radiation-induced skin edema and myeloperoxidase activity. LXA4 efficacy was enhanced by increasing the time of pre-treatment to up to 72 h. LXA4 reduced UV radiation-induced skin edema, neutrophil recruitment (myeloperoxidase activity and LysM-eGFP+ cells), MMP-9 activity, deposition of collagen fibers, epidermal thickness, sunburn cell counts, and production of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-33). Depending on the time point, LXA4 increased the levels of anti-inflammatory cytokines (TGF-β and IL-10). LXA4 significantly attenuated UV radiation-induced oxidative damage returning the oxidative status to baseline levels in parameters such as ferric reducing ability, scavenging of free radicals, GSH levels, catalase activity and superoxide anion production. LXA4 also reduced UV radiation-induced gp91phox [nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) subunit] mRNA expression and enhanced nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream target enzyme nicotinamide adenine dinucleotide (phosphate) quinone oxidoreductase (Nqo1) mRNA expression. ConclusionLXA4 inhibited UV radiation-induced skin inflammation by diminishing pro-inflammatory cytokine production and oxidative stress as well as inducing anti-inflammatory cytokines and Nrf2.

AB074. Genetic variation in CYP2U1, CYP4A11 and CYP4F2 involved in the biosynthesis of hydroxyeicosatetraenoic acids and susceptibility to hypertension and atherosclerosis of various locations

Background: 20-hydroxyeicosatetraenoic acids (20-HETE), products of arachidonic acid metabolism, possess a wide spectrum of important functions in the cardiovascular system and thereby may contribute to the development of many cardiovascular diseases (CVD). CYP2U1, CYP4A11 and CYP4F2 are important enzymes involved in the biosynthesis of 20-HETE and their genetic polymorphisms became attractive markers for testing of the genetic susceptibility to CVD. The present study investigated association between single nucleotide polymorphisms (SNP) of genes coding CYP2U1 (rs1493131), CYP4A11 (rs3890011, rs9332978, rs9333029), CYP4F2 (rs3093098, rs1558139), enzymes involved in the 20-HETE metabolism, and risk of various CVDs.

Polymorphisms of CYP2C8, CYP2C9 and CYP2C19 and risk of coronary heart disease in Russian population

Epoxyeicosatrienoic acids (EETs) are important vasoactive products of arachidonic acid metabolism with a wide range of biological actions in the cardiovascular system. The present study investigated whether single nucleotide polymorphisms (SNP) of genes coding cytochrome P450 2C subfamily, enzymes involved in biosynthesis of EETs, are associated with the risk of coronary heart disease (CHD). A total of 1255 unrelated Russian subjects comprising 561 patients with angiographically diagnosed CHD and 694 age- and sex-matched healthy subjects were included in the study. DNA samples from all study participants were genotyped for six common SNPs rs7909236, rs1934953 of CYP2C8, rs9332242, rs4918758 and rs61886769 of CYP2C9 and rs4244285 of CYP2C19 using by the Mass-ARRAY 4 system. SNP rs4918758 of CYP2C9 was associated with decreased risk of CHD (codominant model) at a borderline significance with odds ratio adjusted for sex and age 0.61 (95% CI: 0.41–0.92, P=0.038, Q=0.20). SNP rs9332242 of CYP2C9 showed a trend towards association with increased CHD risk in cigarette smokers (P=0.049, Q=0.29). Log-likelihood ratio test (LRT) pointed out epistatic interactions between rs9332242 and rs61886769 of CYP2C9 (codominant model, Pinteraction=0.02), however, this P-value did not survive after correction for multiple tests. Bioinformatic analysis revealed a regulatory potential for a majority of the investigated SNPs. Our preliminary results demonstrate that polymorphisms of genes encoding CYP2C subfamily represent potential genetic markers of CHD susceptibility. Further studies are required to substantiate the contribution of these genes to the disease risk.

Recent progress of lipoxins in inflammatory signal pathway

Lipoxins are metabolic products of arachidonic acid, which possess a wide spectrum of adjustment function for various inflammatory cell function and the expression of inflammatory related genes.It is known as stop signals or braking signals of inflammatory response, which can promote the regression of inflammation through regulating a variety of inflammatory signaling pathway.Now, the progress in the regulation of multiple signal pathways by lipoxins and its anti-inflammatory mechanism are reviewed. Key words: Lipoxins; Inflammation; Signaling pathway

Lipoxin A4 suppresses osteoclastogenesis in RAW264.7 cells and prevents ovariectomy-induced bone loss

Lipoxin A4 (LXA4; 5S, 6R, 15Strihydroxy- 7,9,13-trans-11-eicosatetraenoic acid) is a metabolic product of arachidonic acid under the action of lipoxidase. This lipid molecule plays important roles in several biological functions, especially inflammatory processes. In vivo, LXA4 regulates the inflammatory response through several signaling pathways. Its mechanism suggests that it might have an effect on osteoclastogenesis and bone loss. Using both in vitro and in vivo studies, it was here observed that LXA4 could significantly inhibit the formation and function of osteoclasts and these effects could be blocked by Boc-2, the specific inhibitor of FPR2/ALX (the receptor of LXA4). Meanwhile, LXA4 reduce the amount of ovariectomy-induced bone loss. These protective effects was found to be associated with inhibition of nuclear factor-κB (NF-κB), activator protein-1 (AP-1), PI3K-AKT, and p-38, ERK, and JNK in MAPKs. The expression of the receptor activator of the NF-κB ligand RANKL:osteoprotegerin ratio and serum levels of TNF-α, IL-1β, and IL-6 were decreased by LXA4. Moreover, LXA4 prevented the production of reactive oxygen species (ROS), the expression of osteoclast-specific genes, including tartrate-resistant acid phosphatase (TRAP), cathepsin K (CK), matrix metalloproteinase (MMP)-9, RANK, and osteoclastic related transcription factors of c-Fos, NFATc1 could also be significantly inhibited by LXA4 in a dose-dependent manner. Studies have demonstrated that LXA4 can inhibit the formation and function of osteoclasts through modulation of several pathways both upstream and downstream of RANKL signaling and FPR2/ALX wasinvolved in the procedures. This shows that LXA4 may be used as a new strategy for the treatment of osteoclast-related diseases.

Impact of high dose vitamin C on platelet function.

AIMTo examine the effect of high doses of vitamin C (VitC) on ex vivo human platelets (PLTs).METHODSPlatelet concentrates collected for therapeutic or prophylactic transfusions were exposed to: (1) normal saline (control); (2) 0.3 mmol/L VitC (Lo VitC); or (3) 3 mmol/L VitC (Hi VitC, final concentrations) and stored appropriately. The VitC additive was preservative-free buffered ascorbic acid in water, pH 5.5 to 7.0, adjusted with sodium bicarbonate and sodium hydroxide. The doses of VitC used here correspond to plasma VitC levels reported in recently completed clinical trials. Prior to supplementation, a baseline sample was collected for analysis. PLTs were sampled again on days 2, 5 and 8 and assayed for changes in PLT function by: Thromboelastography (TEG), for changes in viscoelastic properties; aggregometry, for PLT aggregation and adenosine triphosphate (ATP) secretion in response to collagen or adenosine diphosphate (ADP); and flow cytometry, for changes in expression of CD-31, CD41a, CD62p and CD63. In addition, PLT intracellular VitC content was measured using a fluorimetric assay for ascorbic acid and PLT poor plasma was used for plasma coagulation tests [prothrombin time (PT), partial thrombplastin time (PTT), functional fibrinogen] and Lipidomics analysis (UPLC ESI-MS/MS).RESULTSVitC supplementation significantly increased PLTs intracellular ascorbic acid levels from 1.2 mmol/L at baseline to 3.2 mmol/L (Lo VitC) and 15.7 mmol/L (Hi VitC, P < 0.05). VitC supplementation did not significantly change PT and PTT values, or functional fibrinogen levels over the 8 d exposure period (P > 0.05). PLT function assayed by TEG, aggregometry and flow cytometry was not significantly altered by Lo or Hi VitC for up to 5 d. However, PLTs exposed to 3 mmol/L VitC for 8 d demonstrated significantly increased R and K times by TEG and a decrease in the α-angle (P < 0.05). There was also a fall of 20 mm in maximum amplitude associated with the Hi VitC compared to both baseline and day 8 saline controls. Platelet aggregation studies, showed uniform declines in collagen and ADP-induced platelet aggregations over the 8-d study period in all three groups (P > 0.05). Collagen and ADP-induced ATP secretion was also not different between the three groups (P > 0.05). Finally, VitC at the higher dose (3 mmol/L) also induced the release of several eicosanoids including thromboxane B2 and prostaglandin E2, as well as products of arachidonic acid metabolism via the lipoxygenases pathway such as 11-/12-/15-hydroxyicosatetraenoic acid (P < 0.05).CONCLUSIONAlterations in PLT function by exposure to 3 mmol/L VitC for 8 d suggest that caution should be exerted with prolonged use of intravenous high dose VitC.

Adding Lyso-Lipids to Arachidonate Metabolism Sets the Stage for New Biology

Prostaglandins have been characterized as the metabolic products of arachidonic acid released from glycerophospholipids following hydrolysis by phospholipase A2s and enzymatic oxidation by the COX1 and COX2. In this issue of Cell Chemical Biology, Liu etal. (2016) examine the metabolism of 2-arachidonoyl-lyso-phosphatidylcholine and 2-arachidonoyl-lyso-phosphatidylethanolamine by COX2 and conversion to glycerolipid linked prostanoids, raising a series of interesting and important questions.