Oncogenic transformation is associated with profound changes in cellular metabolism, but whether tracking these can improve disease stratification or influence therapy decision-making is largely unknown. Using the iKnife to sample the aerosol of cauterized specimens, we demonstrate a new mode of real-time diagnosis, coupling metabolic phenotype to mutant PIK3CA genotype. Oncogenic PIK3CA results in an increase in arachidonic acid and a concomitant overproduction of eicosanoids, acting to promote cell proliferation beyond a cell-autonomous manner. Mechanistically, mutant PIK3CA drives a multimodal signaling network involving mTORC2-PKCζ-mediated activation of the calcium-dependent phospholipase A2 (cPLA2). Notably, inhibiting cPLA2 synergizes with fatty acid-free diet to restore immunogenicity and selectively reduce mutant PIK3CA-induced tumorigenicity. Besides highlighting the potential for metabolic phenotyping in stratified medicine, this study reveals an important role for activated PI3K signaling in regulating arachidonic acid metabolism, uncovering a targetable metabolic vulnerability that largely depends on dietary fat restriction. VIDEO ABSTRACT.

Yangyinqingfei Decoction (YYQFD), a traditional Chinese prescription, is well known in the treatment of diphtheria and lung-related diseases in clinic. However, whether it can be used to block the lung injury caused by air pollutant remains unclear. In the present study, the effect of YYQFD was addressed using a PM2.5-induced lung injury mice model. It was shown that YYQFD significantly improved pulmonary functions of mice exposed to PM2.5, the levels of IL-6, TNF-α and MDA were decreased while SOD levels were increased in serum and bronchoalveolar fluid. The potential mechanism of YYQFD was then delved using metabolomic and proteomic techniques. The protein-metabolite joint analysis showed that YYQFD regulated the biosynthesis of unsaturated fatty acids, linoleic acid and arachidonic acid metabolism, causing a significant decrement of pro-inflammatory mediator arachidonic acid with its downstream metabolites like 20-HETE, prostaglandin E2, accompanied by the up-regulation of PTGES2, GPX2 and CBR3 in lung tissue. These data were used to construct a regulatory metabolic network map in terms of the therapeutic role of YYQFD in PM2.5-induced lung injury, thereby provided a novel insight into potential application in the respiratory diseases caused by air pollutants.

Abnormal lipoprotein metabolism is associated with a variety of diseases, cardiovascular disease in particular. Free fatty acids (FAs) and triglycerides (TGs) are the principal lipid species in adipocytes and are the major components of lipoproteins. However, in routine clinical laboratory testing, only the total plasma concentrations of FAs and TGs are typically measured.

Background: Dietary long chain polyunsaturated fatty acids (LCPUFA) such as arachidonic acid (ARA) and docosahexaenoic acid (DHA) play an important role in the development of the infant immune system. The role of LCPUFA in the T helper type 2 (Th2) biased immune system is unknown. We aimed to understand the effect of feeding LCPUFA during suckling and post-weaning on immune system development in Th2 bias Brown Norway rat offspring. Methods: Brown Norway dams were randomly assigned to nutritionally adequate maternal diet throughout the suckling period (0-3 weeks), namely, control diet (0% ARA, 0% DHA; n= 8) or ARA + DHA (0.45% ARA, 0.8% DHA; n = 10). At 3 weeks, offspring from each maternal diet group were randomized to either a control (0% ARA, 0% DHA; n = 19) or ARA+DHA post-weaning (0.5% ARA, 0.5% DHA; n = 18) diet. At 8 weeks, offspring were killed, and tissues were collected for immune cell function and fatty acid composition analyses. Results: ARA + DHA maternal diet resulted in higher (p < 0.05) DHA composition in breast milk (4×) without changing ARA levels. This resulted in more mature adaptive immune cells in spleen [T regulatory (Treg) cells and B cells], mesenteric lymph nodes (MLN, lower CD45RA+), and Peyer's patches (PP; higher IgG+, B cells) in the ARA+DHA group offspring at 8 weeks. ARA+DHA post-weaning diet (3-8 weeks) resulted in 2 × higher DHA in splenocyte phospholipids compared to control. This also resulted in higher Th1 cytokines, ~50% higher TNF-α and IFNγ, by PMAi stimulated splenocytes ex vivo, with no differences in Th2 cytokines (IL-4, IL-13, and IL-10) compared to controls. Conclusion: Feeding dams a diet higher in DHA during the suckling period resulted in adaptive immune cell maturation in offspring at 8 weeks. Providing ARA and DHA during the post-weaning period in a Th2 biased Brown Norway offspring model may support Th1 biased immune response development, which could be associated with a lower risk of developing atopic diseases.

Visceral fat accumulation is caused by over-nutrition and physical inactivity. Excess accumulation of visceral fat associates with atherosclerosis. Polyunsaturated fatty acids have an important role in human nutrition, but imbalance of dietary long-chain polyunsaturated fatty acids, especially low eicosapentaenoic acid (EPA) / arachidonic acid (AA) ratio, is associated with increased risk of cardiovascular disease. The present study investigated the correlation between EPA, docosahexaenoic acid (DHA), AA parameters and clinical features in male subjects.

Kidney damage is markedly accelerated by high-salt (HS) intake in stroke-prone spontaneously hypertensive rats (SHRSP). Epoxyeicosatrienoic acids (EETs) are epoxygenase products of arachidonic acid which possess vasodepressor, natriuretic, and anti-inflammatory activities. We examined whether up-regulation (clofibrate) or inhibition [N-methylsulfonyl-6-(2-propargyloxyphenyl)hexanamide (MS-PPOH)] of epoxygenase would alter systolic blood pressure (SBP) and/or renal pathology in SHRSP on HS intake (1% NaCl drinking solution). Three weeks of treatment with clofibrate induced renal cortical protein expression of CYP2C23 and increased urinary excretion of EETs compared with vehicle-treated SHRSP. SBP and urinary protein excretion (UPE) were significantly lowered with clofibrate treatment. Kidneys from vehicle-treated SHRSP, which were on HS intake for 3 weeks, demonstrated focal lesions of vascular fibrinoid degeneration, which were markedly attenuated with clofibrate treatment. In contrast, 2 weeks of treatment with the selective epoxygenase inhibitor, MS-PPOH, increased UPE without significantly altering neither urinary EET levels nor SBP. Kidneys from vehicle-treated SHRSP, which were on HS intake for 11 days, demonstrated occasional mild damage whereas kidneys from MS-PPOH-treated rats exhibited widespread malignant nephrosclerosis. These results suggest that pharmacological manipulation of epoxygenase results in divergent effects on renal damage and that interventions to increase EET levels may provide therapeutic strategies for treating salt-sensitive hypertension and renal damage.

The protein alpha-synuclein (αS) self-assembles into toxic beta-sheet aggregates in Parkinson's disease, while it is proposed that αS forms soluble alpha-helical multimers in healthy neurons. Here, we have made αS multimers in vitro using arachidonic acid (ARA), one of the most abundant fatty acids in the brain, and characterized them by a combination of bulk experiments and single-molecule Fӧrster resonance energy transfer (sm-FRET) measurements. The data suggest that ARA-induced oligomers are alpha-helical, resistant to fibril formation, more prone to disaggregation, enzymatic digestion and degradation by the 26S proteasome, and lead to lower neuronal damage and reduced activation of microglia compared to the oligomers formed in the absence of ARA. These multimers can be formed at physiologically-relevant concentrations, and pathological mutants of αS form less multimers than wild-type αS. Our work provides strong biophysical evidence for the formation of alpha-helical multimers of αS in the presence of a biologically relevant fatty acid, which may have a protective role with respect to the generation of beta-sheet toxic structures during αS fibrillation.

Arachidonic acid (ARA, C20:4, n-6), which belongs to the omega-6 series of polyunsaturated fatty acids and has a variety of biological activities, is commercially produced in Mortierella alpina. Dissolved oxygen or oxygen utilization efficiency is a critical factor for Mortierella alpina growth and arachidonic acid production in large-scale fermentation. Overexpression of the Vitreoscilla hemoglobin gene is thought to significantly increase the oxygen utilization efficiency of the cells.

Herein, we expand our previous work on the effects of long chain polyunsaturated fatty acids (LC-PUFA) on the murine hepatic transcriptome using novel statistical and bioinformatic approaches for evaluating microarray data. The analyses focuses on key differences in the transcriptomic response that will influence metabolism following consumption of FUNG (rich in 20:4n6), FISH (rich in 20:5n3, 22:5n3, and 22:6n3) and COMB, the combination of the two.

Acute inflammation is a common feature of many life-threatening pathologies, including septic shock. One hallmark of acute inflammation is the peroxidation of polyunsaturated fatty acids forming bioactive products that regulate inflammation. Myeloperoxidase (MPO) is an abundant phagocyte-derived hemoprotein released during phagocyte activation. Here, we investigated the role of MPO in modulating biologically active arachidonic acid (AA) and linoleic acid (LA) metabolites during acute inflammation. Wild-type and MPO-knockout (KO) mice were exposed to intraperitoneally injected endotoxin for 24 h, and plasma LA and AA oxidation products were comprehensively analyzed using a liquid chromatography-mass spectrometry method. Compared to wild-type mice, MPO-KO mice had significantly lower plasma levels of LA epoxides and corresponding LA- and AA-derived fatty acid diols. AA and LA hydroxy intermediates (hydroxyeicosatetraenoic and hydroxyoctadecadienoic acids) were also significantly lower in MPO-KO mice. Conversely, MPO-deficient mice had significantly higher plasma levels of cysteinyl-leukotrienes with well-known proinflammatory properties. In vitro experiments revealed significantly lower amounts of AA and LA epoxides, LA- and AA-derived fatty acid diols, and AA and LA hydroxy intermediates in stimulated polymorphonuclear neutrophils isolated from MPO-KO mice. Our results demonstrate that MPO modulates the balance of pro- and anti-inflammatory lipid mediators during acute inflammation and, in this way, may control acute inflammatory diseases.

Polyunsaturated fatty acids (PUFAs) have important functions in biological systems. The beneficial effects of dietary PUFAs against inflammatory diseases, cardiovascular diseases, and metabolic disorders have been shown. Studies using cancer cells have presented the anti-tumorigenic effects of docosahexaenoic acid (DHA), an n-3 PUFA, while arachidonic acid (AA), an n-6 PUFA, has been shown to elicit both pro- and anti-tumorigenic effects. In the current study, the anti-tumorigenic effects of AA were evaluated in HT-29 human colon cancer cells. Upon adding AA in the media, more than 90% of HT-29 cells died, while the MCF7 cells showed good proliferation. AA inhibited the expression of SREBP-1 and its target genes that encode enzymes involved in fatty acid synthesis. As HT-29 cells contained lower basal levels of fatty acid synthase, a target gene of SREBP-1, than that in MCF7 cells, the inhibitory effects of AA on the fatty acid synthase levels in HT-29 cells were much stronger than those in MCF-7 cells. When oleic acid (OA), a monounsaturated fatty acid that can be synthesized endogenously, was added along with AA, the HT-29 cells were able to proliferate. These results suggested that HT-29 cells could not synthesize enough fatty acids for cell division in the presence of AA because of the suppression of lipogenesis. HT-29 cells may incorporate more AA into their membrane phospholipids to proliferate, which resulted in ER stress, thereby inducing apoptosis. AA could be used as an anti-tumorigenic agent against cancer cells in which the basal fatty acid synthase levels are low.

Ultrasound assisted enzymatic method was applied to the degumming of arachidonic acid (ARA) oil produced by Mortierella alpina. The conditions of degumming process were optimized by response surface methodology with Box- Behnken design. A dephosphorization rate of 98.82% was achieved under optimum conditions of a 500 U/kg of Phospholipase A1 (PLA1) dosage, 2.8 mL/100 g of water volume, 120 min of ultrasonic time, and 135 W of ultrasonic power. The phosphorus content of ultrasonic assisted enzymatic degumming oil (UAEDO) was 4.79 mg/kg, which was significantly lower than that of enzymatic degumming oil (EDO, 17.98 mg/kg). Crude Oil (CO), EDO and UAEDO revealed the similar fatty acid compositions, and ARA was dominated (50.97 ~ 52.40%). The oxidation stability of UAEDO was equivalent to EDO and weaker than CO, while UAEDO presented the strongest thermal stability, followed by EDO and CO. Furthermore, aldehydes, acids and alcohols were identified the main volatile flavor components for the three oils. The proportions of major contributing components such as hexanal, nonanal, (E)-2-nonanal, (E, E)-2,4-decadienal, (E)-2-nonenal and aldehydes in UAEDO and EDO were all lower than CO. Overall, Ultrasound assisted enzymatic degumming proved to be an efficient and superior method for degumming of ARA oil.

Cyclooxygenase (COXs) and Lipoxygenase (LOXs) pathways are the two major enzymatic pathways in arachidonic acid (AA) metabolism. The term eicosanoid is used to describe biologically active lipid mediators including prostaglandins, thromboxanes, leukotrienes and other oxygenated derivatives, which are produced primarily from AA. Eicosanoids generated in a tissue specific manner play a key role in inflammation and cancer. As AA is the substrate common to variety of COXs and LOXs, inhibition of one pathway results in diversion of the substrate to other pathways, which often is responsible for undesirable side effects. Hence there is need for development of not only isozyme specific inhibitors but also dual/multi enzyme inhibitors. Understanding the interactions of AA and characterizing its binding sites in these enzymes therefore is crucial for developing enzyme specific and multi enzyme inhibitors for enhancing therapeutic efficacy and/or overcoming side effects.

Although some microorganisms can convert glycerol into valuable products such as polyunsaturated fatty acids, the yields are relative low due primarily to an inefficient assimilation of glycerol. Mortierella alpina is an oleaginous fungus which preferentially uses glucose over glycerol as the carbon source for fatty acid synthesis.

Previous studies have shown that lipoprotein apheresis can modify the plasma lipidome and pro-inflammatory and pro-thrombotic lipid mediators. This has not been examined for treatment with protein convertase subtilisin/kexin type 9 inhibitors such as evolocumab, which are increasingly used instead of lipoprotein apheresis in treatment-resistant familial hypercholesterolemia. The aim of this study was to compare the effects of evolocumab treatment and lipoprotein apheresis on the fatty acid profile and on formation of lipid mediators in blood samples.

Polyunsaturated fatty acids such as arachidonic acid (AA) exhibit inhibitory modulation of Kv4 potassium channels. Molecular docking approaches using a Kv4.2 homology model predicted a membrane-embedded binding pocket for AA comprised of the S4-S5 linker on one subunit and several hydrophobic residues within S3, S5 and S6 from an adjacent subunit. The pocket is conserved among Kv4 channels. We tested the hypothesis that modulatory effects of AA on Kv4.2/KChIP channels require access to this site. Targeted mutation of a polar residue (K318) and a nonpolar residue (G314) within the S4-S5 linker as well as a nonpolar residue in S3 (V261) significantly impaired the effects of AA on K (+) currents in Xenopus oocytes. These residues may be important in stabilizing (K318) or regulating access to (V261, G314) the negatively charged carboxylate moiety on the fatty acid. Structural specificity was supported by the lack of disruption of AA effects observed with mutations at residues located near, but not within the predicted binding pocket. Furthermore, we found that the crystal structure of the related Kv1.2/2.1 chimera lacks the structural features present in the proposed AA docking site of Kv4.2 and the Kv1.2/2.1 K (+) currents were unaffected by AA. We simulated the mutagenic substitutions in our Kv4.2 model to demonstrate how specific mutations may disrupt the putative AA binding pocket. We conclude that AA inhibits Kv4 channel currents and facilitates current decay by binding within a hydrophobic pocket in the channel in which K318 within the S4-S5 linker is a critical residue for AA interaction.

Preclinical studies indicate that arachidonic acid (AA)-derived eicosanoids contribute to hyperglycemia-induced kidney injury. We aimed to determine whether plasma and/or urinary levels of dihydroxyeicosatrienoic (DHETs) and 20-hydroxyeicosatetraenoic (20-HETE) acids are associated with diabetic kidney disease (DKD). A total of 334 subjects (132 DKD patients and 202 non-diabetic individuals) were studied. Plasma levels of 11,12-DHET, 14,15-DHET and 20-HETE were measured by LC/MS/MS. Urinary 20-HETE concentrations were determined by immunoenzymatic assay. Subjects with normoalbuminuria had larger 20-HETE-to-creatinine urinary ratios (20-HETE/Cr) than those with micro and macroalbuminuria (p=0.012). Likewise, participants with eGFR>60 ml/min/1.73 m2 had higher plasma levels of 14,15-DHET (p=0.039) and 20-HETE/Cr ratios (p=0.007). Concentrations of 14,15-DHET, 11,12-DHET and 20-HETE/Cr were significantly lower in DKD patients. Median values for non-diabetic vs. DKD were, respectively, 493 (351.0-691.5) vs. 358 (260.5-522) ng/L, p=3e-5; 262 (183.5-356.0) vs. 202 (141.5-278.0) ng/L, p=1e-4 and 5.26 (1.68-11.65) vs. 2.53 (1.01-6.28) ng/mgCr, p=0.010. In addition, 20-HETE/Cr ratios were higher in patients with non-proteinuric DKD than in those with typical DKD (p=0.020). When only individuals with impaired filtration were considered, 14,15-DHET and 11,12-DHET levels were still higher in non-diabetic subjects (p=0.002 and p=0.006, respectively). Our results indicate that AA-derived eicosanoids may play a relevant role in DKD.

Constipation is a common gastrointestinal disorder without effective treatment approach. Buzhongyiqi decoction (BZYQD) is a classical formula that has been commonly used for gastrointestinal disorders for nearly 1,000 years. In this study, we aimed to investigate the protective effect of BZYQD against loperamide-induced constipation and its potential mechanism. Rats with loperamide-induced constipation were orally administered BZYQD. BZYQD treatment obviously increased the small intestinal transit rate and alleviated colon tissue pathological damage. Subsequently, serum metabolomics study was performed to identify the metabolites affected by BZYQD. Metabolomics identified that the levels of 17 serum metabolites, including prostaglandin E2 (PGE2), arachidonic acid (AA), and inositol, were significantly changed in BZYQD-treated group compared with those in the loperamide-induced group. Pathway analysis revealed that those metabolites were mainly associated with arachidonic acid metabolism, biosynthesis of unsaturated fatty acids, ascorbate and aldarate metabolism, inositol phosphate metabolism. Additionally, BZYQD treatment down-regulated the cyclooxygenase-2 expression and decrease production of the proinflammatory mediator PGE2. Further study revealed that BZYQD administration decreased serum levels of the inflammatory factors IL-1β and TNF-α, inhibited phosphorylation of the nuclear transcription factor NF-κB, and down-regulated expression of the inflammatory factors IL-1β and IL-6 in the constipated rat colon. Moreover, BZYQD treatment also increased serum levels of inositol, motilin and gastrin, and promoted gastrointestinal motility. In conclusion, the present study suggested that BZYQD exerted a protective effect against loperamide-induced constipation, which may be associated with its role in regulation of multiple metabolic pathways.

Dietary fatty acids may modulate inflammation in macrophages of the atherosclerotic plaque, affecting its stability. The n-6 polyunsaturated fatty acid (PUFA) arachidonic acid (AA) generally promotes inflammation, while the PUFAs of the n-3 series eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) are considered anti-inflammatory. We determined how these PUFAs influence MMP-9 expression and secretion by the human monocytic cell line (MonoMac 6) at baseline and after 24-hour exposure. MMP-9 protein was measured by zymography and relative levels of MMP-9 mRNA were determined using quantitative real time PCR.

Arachidonic acid is 1 of only 2 unsaturated fatty acids retained in the ovaries of crustaceans and an inhibitor of HR97g, a nuclear receptor expressed in adult ovaries. The authors hypothesized that, as a key fatty acid, arachidonic acid may be associated with reproduction and potentially environmental sex determination in Daphnia. Reproduction assays with arachidonic acid indicate that it alters female:male sex ratios by increasing female production. This reproductive effect only occurred during a restricted Pseudokirchneriella subcapitata diet. Next, the authors tested whether enriching a poorer algal diet (Chlorella vulgaris) with arachidonic acid enhances overall reproduction and sex ratios. Arachidonic acid enrichment of a C. vulgaris diet also enhances fecundity at 1.0 µM and 4.0 µM by 30% to 40% in the presence and absence of pyriproxyfen. This indicates that arachidonic acid is crucial in reproduction regardless of environmental sex determination. Furthermore, the data indicate that P. subcapitata may provide a threshold concentration of arachidonic acid needed for reproduction. Diet-switch experiments from P. subcapitata to C. vulgaris mitigate some, but not all, of arachidonic acid's effects when compared with a C. vulgaris-only diet, suggesting that some arachidonic acid provided by P. subcapitata is retained. In summary, arachidonic acid supplementation increases reproduction and represses pyriproxyfen-induced environmental sex determination in D. magna in restricted diets. A diet rich in arachidonic acid may provide protection from some reproductive toxicants such as the juvenile hormone agonist pyriproxyfen. Environ Toxicol Chem 2015;34:527-535. © 2014 SETAC.